Master bibliography

This is the master bibliography for the H2 Sensing Compendium: a single, deduplicated, citable reference list pooled from the References sections of all 35 modality, foundations, and field pages. Each page carries its own locally numbered reference list (the [1], [2]… you see cited in the body of that page); this master list flattens all of those into one alphabetical index, merges works that several pages cite in common, and records every citing page under each entry. To trace a specific in-text citation, read the number on its own page and match it there — the numbering here is not the per-page numbering. Where a work is cited on more than one page, it appears once below with all of its citing pages listed after “Cited by.” Link-status and reliability notes carried over from the source pages (for example “link dead” or “unverified”) are preserved verbatim.

Coverage: 1148 unique works pooled from 35 pages, with 1448 page-level “Cited by” links. Authored works are listed A–Z by first-author surname; standards, datasheets, vendor documents, and uncredited web resources (which have no personal author) follow at the end, grouped by organization.

ABCDEFGHIJKLMNOPQRSTVWXYZStandards & datasheets

A

• Abgrall, Roueff, Launay, Roncin, Subtil (1989). Wavelengths, oscillator strengths and transition probabilities of the H2 molecule for the Lyman and Werner systems. A&AS 79, 313. ui.adsabs.harvard.edu. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• S. Acharya, B. Srinivasan, D. Shanahan, U. Roedig, A. O’Riordan, V. S. Nagaraja (2025). Surface Acoustic Wave Gas Sensors: Innovations in Functional Materials, Sensing Dynamics, and Signal Analysis. arXiv:2510.04940, Tyndall National Institute, University College Cork. arxiv.org. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Adjie, N., Bordes, C., Brito, D., Nasri, D., Normandin, É. (Université de Pau et des Pays de l’Adour, CNRS/LFCR-IPREM) (2025). In-soil hydrogen concentration monitoring using MONHyTOR: application for natural hydrogen exploration. Advances in Geosciences 67, 57. adgeo.copernicus.org. — Cited by: Why hydrogen is hard to sense, Metal-oxide (MOX) chemiresistors, Palladium resistive & nanomaterial sensors, Electrochemical cells (amperometric & potentiometric), Plasmonic & metamaterial sensors, Gas chromatography (lab, micro, and field GC), Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design, Sensor arrays, e-noses & machine-learning selectivity.
• Alter, M.D., Steiof, M. (2005). Optimized method for dissolved hydrogen sampling in groundwater. Journal of Contaminant Hydrology 78(1–2), 71–86. sciencedirect.com; pubmed.ncbi.nlm.nih.gov. — Cited by: Dissolved H2 in groundwater & formation water.
• Arachchige, C. M.; Muller, A. (2025). Portable Raman hydrogen concentration mapping with parts-per-billion sensitivity. Applied Optics 64(13), 3646–3654. 10.1364/AO.558965 opg.optica.org. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Artursson, T. et al. (2000). Drift correction for gas sensors using multivariate methods. Journal of Chemometrics 14, 711–723. analyticalsciencejournals.onlinelibrary.wiley.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Avetisov, V., Bjørøy, Ø., Wang, J., Geiser, P., Paulsen, K.G. (2019). Hydrogen Sensor Based on Tunable Diode Laser Absorption Spectroscopy. Sensors 19(23), 5313. 10.3390/s19235313 pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense, IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

B

• Baer, D.S., Paul, J.B., Gupta, M., O’Keefe, A. (2002). Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy. Appl. Phys. B 75, 261–265. ui.adsabs.harvard.edu. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Banks, E.W., Smith, J.M.C., Hatch, M., Burk, D., Suckow, A. (2017). Sampling Dissolved Gases in Groundwater at in Situ Pressure: A Simple Method for Reducing Uncertainty in Hydrogeological Studies of Coal Seam Gas Exploration. Environmental Science & Technology Letters 4(12), 535–539. 10.1021/acs.estlett.7b00457 pubs.acs.org. — Cited by: Dissolved H2 in groundwater & formation water.
• Bannenberg, L. J. et al. (2021). Tantalum–Palladium: Hysteresis-Free Optical Hydrogen Sensor Over 7 Orders of Magnitude in Pressure with Sub-Second Response. Advanced Functional Materials. 10.1002/adfm.202010483 advanced.onlinelibrary.wiley.com. — Cited by: Plasmonic & metamaterial sensors.
• Baranzahi, A. et al. (n.d.). Pd- and Pt-SiC Schottky diodes for detection of H2 and CH4 at high temperature. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Barnes, D.H. et al. (2003). Hydrogen in the atmosphere: Observations above a forest canopy in a polluted environment. J. Geophys. Res. Atmos.. agupubs.onlinelibrary.wiley.com. — Cited by: Why hydrogen is hard to sense.
• Barsan, N.; Weimar, U. (2001). Conduction Model of Metal Oxide Gas Sensors. Journal of Electroceramics 7, 143–167. link.springer.com. — Cited by: Metal-oxide (MOX) chemiresistors, How the sensor families actually differ: a transduction decoder.
• D. R. Baselt, B. Fruhberger, E. Klaassen, S. Cemalovic, C. L. Britton, S. V. Patel, T. E. Mlsna, D. McCorkle, B. Warmack (2003). Design and performance of a microcantilever-based hydrogen sensor. Sensors and Actuators B: Chemical 88(2):120–131. 10.1016/S0925-4005(02)00315-5. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Bertagni, M.B. et al. (2021). Moisture Fluctuations Modulate Abiotic and Biotic Limitations of H2 Soil Uptake. Global Biogeochemical Cycles. agupubs.onlinelibrary.wiley.com. — Cited by: Environmental covariance & signal interpretation.
• Bjornstad, B.N., McKinley, J.P., Stevens, T.O., Rawson, S.A., Fredrickson, J.K., Long, P.E. (1994). Generation of Hydrogen Gas as a Result of Drilling Within the Saturated Zone. Groundwater Monitoring & Remediation 14(3), 140–147. 10.1111/j.1745-6592.1994.tb00492.x ngwa.onlinelibrary.wiley.com. — Cited by: Mud-gas logging for H2 while drilling.
• Blake, A.J. (1979). An atmospheric absorption model for the Schumann-Runge bands of oxygen. J. Geophys. Res. Space Phys.. agupubs.onlinelibrary.wiley.com. — Cited by: Why hydrogen is hard to sense.
• Boon-Brett, L.; Bousek, J.; Black, G.; Moretto, P.; Castello, P.; Hübert, T.; Banach, U. (2010). Identifying performance gaps in hydrogen safety sensor technology for automotive and stationary applications. Int. J. Hydrogen Energy 35, 373–384. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Boysen, D.A.; Uda, T.; Chisholm, C.R.; Haile, S.M. (2004). High-Performance Solid Acid Fuel Cells through Humidity Stabilization. Science 303, 68–70. 10.1126/science.1090920. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• M. S. Brennwald et al. (2016). A Portable and Autonomous Mass Spectrometric System for On-Site Environmental Gas Analysis. Environmental Science & Technology 50(24), 13455. pubs.acs.org. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Brennwald, M.S., Rinaldi, A.P., Gisiger, J., Zappone, A., Kipfer, R. (2024). Gas equilibrium membrane inlet mass spectrometry (GE-MIMS) for water at high pressure. Geoscientific Instrumentation, Methods and Data Systems 13, 1–16. gi.copernicus.org. — Cited by: Dissolved H2 in groundwater & formation water.
• Brokaw, R.S. (1965). Viscosity and Thermal Conductivity of Gas Mixtures. Accuracy of Some Empirical Formulas. Journal of Chemical Physics 42(7), 2533 (Wassiljewa equation performance for binary vs. multicomponent gas mixtures). ui.adsabs.harvard.edu. — Cited by: Environmental covariance & signal interpretation.
• Brosha, E.L.; Garzon, F.H.; Glass, R.S.; Kreller, C.; Mukundan, R.; Padro, C.G.; Woo, L. (2012). VIII.8 Leak Detection and H₂ Sensor Development for Hydrogen Applications. DOE Hydrogen and Fuel Cells Program FY 2012 Annual Progress Report, pp. VIII-36–41. hydrogen.energy.gov. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Butler, M.A. (1984). Optical fiber hydrogen sensor. Applied Physics Letters 45, 1007. pubs.aip.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Butler, M.A. & Ginley, D.S. (1988). Hydrogen sensing with palladium-coated optical fibers. Journal of Applied Physics 64, 3706. pubs.aip.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Buttner, W., Rivkin, C., Burgess, R., Hartmann, K., Bloomfield, I., Bubar, M., Post, M., Boon-Brett, L., Weidner, E., Moretto, P. (n.d.). Hydrogen Monitoring Requirements in the Global Technical Regulation on Hydrogen and Fuel Cell Vehicles. NREL / EC Joint Research Centre, OSTI 1353421. osti.gov. — Cited by: Standards, regulations & certification.

C

• Chabab, S., Théveneau, P., Coquelet, C., Corvisier, J., Paricaud, P. (2020). Measurements and predictive models of high-pressure H2 solubility in brine (H2O+NaCl) for underground hydrogen storage application. International Journal of Hydrogen Energy 45, 32206–32220. sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Chapelle, F.H. et al. (1995). Deducing the Distribution of Terminal Electron-Accepting Processes in Hydrologically Diverse Ground Water Systems. Water Resources Research 31(2), 359–371. agupubs.onlinelibrary.wiley.com. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Chapelle, F.H., Vroblesky, D.A., Woodward, J.C., Lovley, D.R. (1997). Practical Considerations for Measuring Hydrogen Concentrations in Groundwater. Environmental Science & Technology 31(10), 2873–2877. 10.1021/es970085c usgs.gov. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Chatton, E., Labasque, T., de La Bernardie, J., Guihéneuf, N., Bour, O., Aquilina, L. (2017). Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow. Environmental Science & Technology 51(2), 846–854. 10.1021/acs.est.6b03706. — Cited by: Dissolved H2 in groundwater & formation water.
• Cho, S.-Y., Koh, H.-J., Yoo, H.-W., Jung, H.-T. (2017). Tunable Chemical Sensing Performance of Black Phosphorus by Controlled Functionalization with Noble Metals. Chemistry of Materials 29(17), 7197–7205. pubs.acs.org. — Cited by: 2D-material & nanostructure FET sensors.
• Cipriano, D., Capelli, L. (2019). Evolution of Electronic Noses from Research Objects to Engineered Environmental Odour Monitoring Systems: A Review of Standardization Approaches. Biosensors 9(2), 75. 10.3390/bios9020075 pmc.ncbi.nlm.nih.gov. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Coddington, I., Newbury, N., Swann, W. (2016). Dual-comb spectroscopy. Optica 3, 414–426. nist.gov; pmc.ncbi.nlm.nih.gov. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• I. Constantinoiu, D. Miu, C. Viespe (2022). SAW Hydrogen Sensors with Pd/SnO2 Layers. Materials 15(22):8012, INFLPR Romania / Politehnica Bucharest. 10.3390/ma15228012 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Coveney, R.M. et al. (1987). Serpentinization and the origin of hydrogen gas in Kansas. AAPG Bulletin 71(1), 39–48. archives.datapages.com; osti.gov. — Cited by: Isotopic & genetic fingerprinting.
• Crozier, T.E., Yamamoto, S. (1974). Solubility of hydrogen in water, sea water, and sodium chloride solutions. Journal of Chemical & Engineering Data 19(3), 242–244. 10.1021/je60062a007. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• B. Cui, L. Cheng, X. Xue, J. Jin, L. Huang, Y. Liang, W. Wang (2026). High sensitivity SAW hydrogen gas sensor based on thermal conductivity effect. Microsystems & Nanoengineering, Institute of Acoustics, Chinese Academy of Sciences. nature.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

D

• Dąbrowski, A.; Kuczyński, S.; Barbacki, J.; Włodek, T.; Smulski, R.; Nagy, S. (2019). Downhole measurements and determination of natural gas composition using Raman spectroscopy. Journal of Natural Gas Science and Engineering 65, 25–31. sciencedirect.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Davies, K. et al. (2024). A natural hydrogen seep in Western Australia: Observed characteristics and controls. Science and Technology for Energy Transition. 10.2516/stet/2024043 stet-review.org. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Helium, noble gases & co-tracers, Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Davies, K., Esteban, L., Keshavarz, A., Iglauer, S. (2024). Advancing Natural Hydrogen Exploration: Headspace Gas Analysis in Water-Logged Environments. Energy & Fuels. 10.1021/acs.energyfuels.3c04562 pubs.acs.org. — Cited by: Soil-gas surveys: hardware, protocols & survey design, Dissolved H2 in groundwater & formation water.
• Davies, K., Haines, P.W., Thomas, C., Normore, L. (2025). Natural hydrogen soil gas emissions near Harvey, Perth Basin: a comparative study of survey methods. Sci. Technol. Energy Transition 80, 46. 10.2516/stet/2025026 stet-review.org (does not itemize the iBrid Mx6/GA5000 internal sensor technology). — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Raman spectroscopy (spontaneous, gas phase), Catalytic pellistors, Metal-oxide (MOX) chemiresistors, Palladium resistive & nanomaterial sensors, Mass spectrometry (portable, membrane-inlet, isotopes), Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• Davies, K., Josse, R., Frery, E., Esteban, L., Keshavarz, A., Iglauer, S. (2025). Distinguishing drilling-induced artifacts from naturally occurring hydrogen in soil gas surveys: Insights from sub-circular depressions. International Journal of Hydrogen Energy 109, 1230–1240. ro.ecu.edu.au; sciencedirect.com. — Cited by: Electrochemical cells (amperometric & potentiometric), Downhole & borehole H2 sensing, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• de Groot, W. A. (NYMA, Inc., for NASA Lewis Research Center). (1994). The Use of Spontaneous Raman Scattering for Hydrogen Leak Detection. AIAA-1994-2983; NASA-CR-195373; NASA Technical Reports Server 19950004589. ntrs.nasa.gov. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• de Lima Leon, J.A., Penteado, H.L.B., Ellis, G.S., Milkov, A.V., Mendonça Filho, J.G. (2024). Recognition of Artificial Gases Formed during Drill-Bit Metamorphism Using Advanced Mud Gas. Energies 17(17), 4383. 10.3390/en17174383 mdpi.com. — Cited by: Mud-gas logging for H2 while drilling.
• de Lima Leon, J.A. et al. (2025). Machine Learning Approach to Support Mud Gas Evaluation and Detect DBM in Oil Wells. First EAGE Workshop on Surface Logging, 2025. 10.3997/2214-4609.202535038 earthdoc.org. — Cited by: Mud-gas logging for H2 while drilling.
• Dennler, N.; Rastogi, S.; Fonollosa, J.; van Schaik, A.; Schmuker, M. (n.d.). Drift in a Popular Metal Oxide Sensor Dataset Reveals Limitations for Gas Classification Benchmarks. arXiv:2108.08793. arxiv.org. — Cited by: Metal-oxide (MOX) chemiresistors, Sensor arrays, e-noses & machine-learning selectivity.
• J. Devkota, P. R. Ohodnicki, D. W. Greve (2017). SAW Sensors for Chemical Vapors and Gases. Sensors 17(4):801, NETL/CMU. 10.3390/s17040801 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• J. Devkota, E. Mao, D. W. Greve, P. R. Ohodnicki, J. Baltrus (2022). A Surface Acoustic Wave Hydrogen Sensor with Tin Doped Indium Oxide Layers for Intermediate Temperatures. Sensors and Actuators B: Chemical 354, 131229, NETL/Carnegie Mellon University. osti.gov; sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Draine, B.T. & Bertoldi, F. (1996). Structure of Stationary Photodissociation Fronts. ApJ 468, 269; arXiv:astro-ph/9603032. arxiv.org; see also citing/using discussion in Wolcott-Green, Haiman & Bryan, “Photodissociation of H2 in Protogalaxies,” MNRAS 418, 838 (2011), arXiv:1106.3523. arxiv.org (Note: the specific numeric fitting-formula coefficients commonly attributed to Draine & Bertoldi 1996 were not independently re-verified from the primary text in this session and are therefore not reproduced here; the qualitative self-shielding behavior is asserted with confidence, but the specific column-density thresholds attributed to [6] are unverified — see the note on reference [6].). — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Duan, C.; Tong, J.; Shang, M.; Nikodemski, S.; Sanders, M.; Ricote, S.; Almansoori, A.; O’Hayre, R. (2015). Readily processed protonic ceramic fuel cells with high performance at low temperatures. Science 349(6254), 1321–1326. 10.1126/science.aab3987. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

E

• Ebert, J.N.; Jennings, D.; Schäfer, L.-A.; Sebold, D.; Rheinheimer, W. (2024). Bulk and grain boundary conductivity in doped BaZrO3: Bulk contribution dominates at operating temperatures. Scripta Materialia 241, 115852. sciencedirect.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Ehhalt, D.H., Rohrer, F. (2013). Deposition velocity of H2: a new algorithm for its dependence on soil moisture and temperature. Tellus B: Chemical and Physical Meteorology 65(1), 19904. 10.3402/tellusb.v65i0.19904 b.tellusjournals.se. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• K. L. Ekinci, Y. T. Yang, X. M. H. Huang, M. L. Roukes et al. (2005). Nanomechanical hydrogen sensing. Applied Physics Letters 86, 143104. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Emperhoff, S., Eberl, M., Dwertmann, T., Wöllenstein, J. (2024). On the Influence of Humidity on a Thermal Conductivity Sensor for the Detection of Hydrogen. Sensors 24(9), 2697. 10.3390/s24092697 pmc.ncbi.nlm.nih.gov. — Cited by: Environmental covariance & signal interpretation.
• Eriksson, M., Lundström, I., Ekedahl, L.-G. (1997). A model of the Temkin isotherm behavior for hydrogen adsorption at Pd–SiO2 interfaces. J. Appl. Phys. 82(6), 3143–3146, pubs.aip.org. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, How the sensor families actually differ: a transduction decoder.

F

• Favier, F.; Walter, E. C.; Zach, M. P.; Benter, T.; Penner, R. M. (2001). Hydrogen Sensors and Switches from Electrodeposited Palladium Mesowire Arrays. Science 293(5538), 2227–2231. 10.1126/science.1063189 science.org. — Cited by: Palladium resistive & nanomaterial sensors, How the sensor families actually differ: a transduction decoder.
• Fernandez, L., Yan, J., Fonollosa, J., Burgués, J., Gutierrez, A., Marco, S. (2018). A Practical Method to Estimate the Resolving Power of a Chemical Sensor Array: Application to Feature Selection. Frontiers in Chemistry 6, 209. 10.3389/fchem.2018.00209 frontiersin.org. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Fiber-enhanced Raman spectroscopy for highly sensitive H2 and SO2 sensing with a hollow-core anti-resonant fiber, Wang et al., Optics Express 29(20):32296, 2021 (2021). opg.optica.org; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Firth, J.G., Jones, A., Jones, T.A. (1973). The principles of the detection of flammable atmospheres by catalytic devices. Combustion and Flame, Vol. 20, Issue 3, pp. 303–311, as cited in Clairair [4]; journal record: sciencedirect.com. — Cited by: Catalytic pellistors.
• B. Fisher (n.d.). Surface Acoustic Wave (SAW) Cryogenic Liquid And Hydrogen Gas Sensors. PhD dissertation, University of Central Florida (D. C. Malocha group). stars.library.ucf.edu. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Fleurbaey, H., Kassi, S., Campargue, A. (2024). Room temperature detection of the (H2)2 dimer. Phys. Chem. Chem. Phys. 26, 21974–21981. 10.1039/D4CP02605E pubs.rsc.org. — Cited by: Why hydrogen is hard to sense.
• Fogelberg, Eriksson, Dannetun, Petersson (1995). J. Appl. Phys. 78, 988. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Fonollosa, J., Fernández, L., Gutiérrez-Gálvez, A., Huerta, R., Marco, S. (2016). Calibration transfer and drift counteraction in chemical sensor arrays using Direct Standardization. Sensors and Actuators B: Chemical 236, 1044–1053. sciencedirect.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Fredriksson, H.; Alaverdyan, Y.; Dmitriev, A.; Langhammer, C.; Sutherland, D. S.; Zäch, M.; Kasemo, B. (2007). Hole–Mask Colloidal Lithography. Advanced Materials 19(23), 4297–4302. 10.1002/adma.200700680 advanced.onlinelibrary.wiley.com. — Cited by: Plasmonic & metamaterial sensors.
• Fujimoto et al. (2012). Development of Laser-Produced Tin Plasma-Based EUV Light Source Technology for HVM EUV Lithography. Physics Research International 249495. onlinelibrary.wiley.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

G

• Gardner, J.W., Bartlett, P.N. (1994). A brief history of electronic noses. Sensors and Actuators B: Chemical 18–19, 210–211. sciencedirect.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• S. Garrett (2008). Sonic gas analyzer for hydrogen and methane. Acoustics’08 Paris proceedings paper 000614, conforg.fr (fetch unsuccessful — 404; content sourced via Acoustical Society of America press summary, see [19]); also indexed at J. Acoust. Soc. Am. 123, 3372, pubs.aip.org and ResearchGate researchgate.net. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Garzon, F.H.; Mukundan, R.; Brosha, E.L. (2000). Solid state mixed potential gas sensors: theory, experiments and challenges. Solid State Ionics 136–137, 633–638. sciencedirect.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Gelman, S.E., Hearon, J.S., Ellis, G.S. (2025). Prospectivity Mapping for Geologic Hydrogen. U.S. Geological Survey Professional Paper 1900. 10.3133/pp1900 pubs.usgs.gov. — Cited by: Mud-gas logging for H2 while drilling, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• Gies et al. (1982). The Schumann-Runge continuum of oxygen at wavelengths greater than 175 nm. JGR 87, A10, 8307 — cross section context “>10⁻¹⁷ cm², comparable to the ionization continuum.” ui.adsabs.harvard.edu. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Giglio, M., Patimisco, P. et al. (2015). Allan Deviation Plot as a Tool for Quartz-Enhanced Photoacoustic Sensors Noise Analysis. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (PubMed 26529758). pubmed.ncbi.nlm.nih.gov. — Cited by: Reading a sensor datasheet.
• Giorgetta, F., et al. (2021). Open-Path Dual-Comb Spectroscopy for Multispecies Trace Gas Detection in the 4.5–5 µm Spectral Region. Laser Photonics Rev. 15, 2000583. onlinelibrary.wiley.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• G. Giubilei, F. Ben Ayed, Y. Sautriot, A. Venditti, K. Zhang, S. D. Calisgan, P. Simeoni, Z. Qian, M. Rinaldi (2025). Palladium-Coated Laterally Vibrating Resonators (LVRs) for Hydrogen Sensing. arXiv:2509.04511, Institute for NanoSystems Innovation, Northeastern University. arxiv.org. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Gorbova, E.; Balkourani, G.; Molochas, C.; Sidiropoulos, D.; Brouzgou, A.; Demin, A.; Tsiakaras, P. (2022). Brief Review on High-Temperature Electrochemical Hydrogen Sensors. Catalysts 12(12), 1647. 10.3390/catal12121647. — Cited by: Electrochemical cells (amperometric & potentiometric), Solid-electrolyte & high-temperature electrochemical sensors.
• Gordon, I.E., Rothman, L.S., Hargreaves, R.J., et al. (2022). The HITRAN2020 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Transfer 277, 107949. 10.1016/j.jqsrt.2021.107949 sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Guélard, J. et al. (2017). Natural H2 in Kansas: Deep or shallow origin? Geochemistry, Geophysics, Geosystems 18(5). 10.1002/2016GC006544. — Cited by: Dissolved H2 in groundwater & formation water.
• Guo, J.; Luo, Z.; Liu, Q.; Yang, D.; Dong, H.; Huang, S.; Kong, A.; Wu, L. (2021). High-Sensitivity Raman Gas Probe for In Situ Multi-Component Gas Detection. Sensors 21(10), 3539. 10.3390/s21103539 pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).

H

• Halas, P., Dupuy, A., Franceschi, M., Bordmann, V., Fleury, J-M., Duclerc, D. (2021). Hydrogen gas in circular depressions in South Gironde, France: Flux, stock, or artefact?. Applied Geochemistry 127, 104928. 10.1016/j.apgeochem.2021.104928 sciencedirect.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.
• Halley, D.; Sleight, J.; Ramaiyan, K.P.; Tsui, L.-K.; Garzon, F. (2022). A review of zirconia oxygen, NOx, and mixed potential gas sensors – History and current trends. Sensors and Actuators B: Chemical 370, 132363. 10.1016/j.snb.2022.132363. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• S. S. Harilal, E. J. Kautz (2024). Analysis of hydrogen and lithium isotopes using Laser-Induced Breakdown Spectroscopy. Proc. SPIE High-Power Laser Ablation VIII; PNNL publication record. pnnl.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Hecht, E. S. (2020). Hydrogen detection via Raman scattering. SAND2020-11172PE, Sandia National Laboratories, October 2020. osti.gov. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Herzberg, G. (1949). Quadrupole Rotation-Vibration Spectrum of the Hydrogen Molecule. Nature 163, 170. ui.adsabs.harvard.edu. — Cited by: Why hydrogen is hard to sense, IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Hinojo, R., Soriano, L., Abellà, J., Colominas, S. (2020). Evaluation of High-Temperature Hydrogen Sensors Based on BaCe0.6Zr0.3Y0.1O3-α and Sr(Ce0.9Zr0.1)0.95Yb0.05O3-α Perovskites for Industrial Applications. Sensors 20(24), 7258. 10.3390/s20247258 pmc.ncbi.nlm.nih.gov. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors, Downhole & borehole H2 sensing.
• Hodgkinson, J., Tatam, R.P. (2013). Optical gas sensing: a review. Meas. Sci. Technol. 24, 012004. 10.1088/0957-0233/24/1/012004. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Hoehler, T.M. (1998). Thermodynamic control on hydrogen concentrations in anoxic sediments. Geochimica et Cosmochimica Acta 62(10), 1745–1756. sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Hoehler, T.M. et al. (2001). Apparent minimum free energy requirements for methanogenic Archaea and sulfate-reducing bacteria in an anoxic marine sediment. FEMS Microbiology Ecology 38(1), 33–41. academic.oup.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Y. S. Huang, Y. Y. Chen, T.-T. Wu (2010). A passive wireless hydrogen surface acoustic wave sensor based on Pt-coated ZnO nanorods. Nanotechnology 21, 095503. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Huber, M. L. and Harvey, A. H. (n.d.). Thermal Conductivity of Gases. NIST/CRC Handbook reference table. tsapps.nist.gov. — Cited by: Gas chromatography (lab, micro, and field GC).
• Hübert, T., Boon-Brett, L., Black, G., Banach, U. (2011). Hydrogen sensors – A review. Sensors and Actuators B: Chemical 157, 329–352. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors, Solid-electrolyte & high-temperature electrochemical sensors.
• Hübert, T., Majewski, J., Banach, U., Detjens, M., Tiebe, C. (2017). Response Time Measurement of Hydrogen Sensors. BAM Federal Institute for Materials Research and Testing / Lublin University of Technology. hysafe.info. — Cited by: Standards, regulations & certification.
• Hughes, R. C.; Schubert, W. K. (1994). Extended range chemical sensing apparatus. US Patent 5,279,795. patents.google.com. — Cited by: Palladium resistive & nanomaterial sensors.
• Hughes, R. C.; Schubert, W. K.; Buss, R. J. (1995). Solid-State Hydrogen Sensors Using Palladium-Nickel Alloys: Effect of Alloy Composition on Sensor Response. Journal of The Electrochemical Society 142(1), 249. 10.1149/1.2043887 iopscience.iop.org. — Cited by: Palladium resistive & nanomaterial sensors.

I

• Iwahara, H.; Uchida, H.; Ogaki, K.; Nagato, H. (1991). Nernstian Hydrogen Sensor Using BaCeO₃-Based, Proton-Conducting Ceramics Operative at 200–900 °C. J. Electrochem. Soc. 138, 295–299. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

J

• Jordan, A. & Steinberg, B. (2011). Calibration of atmospheric hydrogen measurements. Atmospheric Measurement Techniques 4, 509–521. amt.copernicus.org. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• D. S. Ballantine Jr., R. M. White, S. J. Martin, A. J. Ricco, E. T. Zellers, G. C. Frye, H. Wohltjen (1997). Acoustic Wave Sensors: Theory, Design, and Physico-Chemical Applications, Academic Press, 1997. ISBN 0-12-077460-7. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

K

• Kassi, S., Campargue, A. (2012). The absorption spectrum of H2: CRDS measurements of the (2-0) band, review of the literature data and accurate ab initio line list up to 35 000 cm−1. Phys. Chem. Chem. Phys.. pubs.rsc.org (PDF: fuw.edu.pl). — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Kim, K.-H.; et al. (2024). Long-term reliable wireless H2 gas sensor via repeatable thermal refreshing of palladium nanowire. Nature Communications 15, 8761. 10.1038/s41467-024-53080-0 pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors, Palladium resistive & nanomaterial sensors.
• Kong, J., Chapline, M.G., Dai, H. (2001). Functionalized Carbon Nanotubes for Molecular Hydrogen Sensors. Advanced Materials 13(18), 1384–1386. advanced.onlinelibrary.wiley.com13:18%3C1384::AID-ADMA1384%3E3.0.CO;2-8. — Cited by: 2D-material & nanostructure FET sensors.
• Korotcenkov, G.; Han, S.D.; Stetter, J.R. (2009). Review of Electrochemical Hydrogen Sensors. Chem. Rev. 109(3), 1402–1433. 10.1021/cr800339k. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Kosterev, A.A., Tittel, F.K., et al. (2005). Applications of quartz tuning forks in spectroscopic gas sensing. Rev. Sci. Instrum. 76, 043105. ui.adsabs.harvard.edu. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

L

• U.S. EPA (National Risk Management Research Laboratory / National Exposure Research Laboratory). (n.d.). Leak, Purge, and Gas Permeability Testing to Support Active Soil Gas Sampling. cfpub.epa.gov (see also related EPA record “Evaluation of Vapor Equilibration and Impact of Purge Volume on Soil-Gas Sampling Results,” cfpub.epa.gov). — Cited by: Soil-gas surveys: hardware, protocols & survey design.
• LaConti, A. G. & Maget, H. J. R. (1971). Electrochemical Detection of H₂, CO and Hydrocarbons in Inert or Oxygen Atmospheres. Journal of the Electrochemical Society 118(3), 1971. — Cited by: Electrochemical cells (amperometric & potentiometric), How the sensor families actually differ: a transduction decoder.
• Langhammer, C.; Yuan, Z.; Zorić, I.; Kasemo, B. (2007). Hydrogen storage in Pd nanodisks characterized with a novel nanoplasmonic sensing scheme. PubMed ID: 17850168. pubmed.ncbi.nlm.nih.gov. — Cited by: Plasmonic & metamaterial sensors.
• Langhammer, C.; Larsson, E. M.; Kasemo, B.; Zorić, I. (2010). Indirect Nanoplasmonic Sensing: Ultrasensitive Experimental Platform for Nanomaterials Science and Optical Nanocalorimetry. Nano Letters 10(9), 3529–3538. 10.1021/nl101727b pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Le, V-H., Caumon, M-C., Pironon, J., de Donato, P., Piedevache, M., Randi, A., Lorgeoux, C., Barres, O. (2023). Quantitative monitoring of dissolved gases in a flooded borehole: calibration of the analytical tools. Science and Technology for Energy Transition 78, 21. 10.2516/stet/2023017 stet-review.org. — Cited by: Downhole & borehole H2 sensing.
• Lee, J.S. et al. (2015). Wireless Hydrogen Smart Sensor Based on Pt/Graphene-Immobilized Radio-Frequency Identification Tag. ACS Nano 9(8). 10.1021/acsnano.5b02024 pubs.acs.org. — Cited by: 2D-material & nanostructure FET sensors.
• Lévy, D. et al. (2023). Natural H2 exploration: tools and workflows to characterize a play. Science and Technology for Energy Transition 78, 27. 10.2516/stet/2023021 stet-review.org. — Cited by: Why hydrogen is hard to sense, Fiber-optic & chemochromic hydrogen sensors, Mass spectrometry (portable, membrane-inlet, isotopes), Geologic context: the measurement problem in H2 exploration, Helium, noble gases & co-tracers, Isotopic & genetic fingerprinting.
• Li, L.; Zhang, X.; Luan, Z.; Du, Z.; Xi, S.; Wang, B.; Cao, L.; Lian, C.; Yan, J. (2018). Raman vibrational spectral characteristics and quantitative analysis of H2 up to 400 °C and 40 MPa. J. Raman Spectrosc. 49(10), 1722–1731. 10.1002/jrs.5420. — Cited by: Why hydrogen is hard to sense, Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Lin, L.-H., Slater, G.F., Sherwood Lollar, B., Lacrampe-Couloume, G., Onstott, T.C. (2005). The yield and isotopic composition of radiolytic H2, a potential energy source for the deep subsurface biosphere. Geochimica et Cosmochimica Acta 69(4), 893–903. sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• J. Liu, D. K. T. Ng, Y. Koh, S. Samanta, W. Chen, M. H. K. Md Husni, M. Srinivas, Q. Zhang, F. M. Kai, P. H. K. Chang, Y. Zhu (2025). High-Performance Piezoelectric Micro Diaphragm Hydrogen Sensor. ACS Sensors, IME and NMC, A*STAR Singapore. 10.1021/acssensors.4c03069 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Lloyd Spetz, A. (2001). SiC Based Field Effect Gas Sensors for Industrial Applications. physica status solidi (a) 185(1), 15; SenSiC, sensic.se. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Lopez-Lazaro, C., Bachaud, P., Moretti, I., Ferrando, N. (2019). Predicting the phase behavior of hydrogen in NaCl brines by molecular simulation for geological applications. BSGF - Earth Sciences Bulletin, 2019. 10.1051/bsgf/2019008 bsgf.fr. — Cited by: Downhole & borehole H2 sensing.
• Lovley, D.R., Goodwin, S. (1988). Hydrogen concentrations as an indicator of the predominant terminal electron-accepting reactions in aquatic sediments. Geochimica et Cosmochimica Acta 52(12), 2993–3003. pubs.usgs.gov; sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Lovley, D.R., Chapelle, F.H., Woodward, J.C. (1994). Use of Dissolved H2 Concentrations To Determine Distribution of Microbially Catalyzed Redox Reactions in Anoxic Groundwater. Environmental Science & Technology 28(7), 1205–1210. pubs.acs.org. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.
• Lundström, I., Shivaraman, S., Svensson, C., Lundkvist, L. (1975). A hydrogen-sensitive MOS field-effect transistor. Applied Physics Letters 26, 55–57, DOI 10.1063/1.88053. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, How the sensor families actually differ: a transduction decoder.
• Lundström, I. et al. (2007). Twenty-five years of field effect gas sensor research in Linköping. Sensors and Actuators B 121(1), 247–262, DOI 10.1016/j.snb.2006.09.046. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.

M

• Ma, E., Xu, Z., Sun, A., Yang, S., Jiang, J. (2025). High-Performance Hydrogen Gas Sensor Based on Pd-Doped MoS2/Si Heterojunction. Sensors 25(15), 4753. 10.3390/s25154753 pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Maiga, O., Deville, E., Laval, J., Prinzhofer, A., Diallo, A.B. (2023). Characterization of the spontaneously recharging natural hydrogen reservoirs of Bourakebougou in Mali. Scientific Reports 13, 11876. 10.1038/s41598-023-38977-y pmc.ncbi.nlm.nih.gov. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Helium, noble gases & co-tracers, Dissolved H2 in groundwater & formation water.
• A. Marcu, C. Viespe (2017). Surface Acoustic Wave Sensors for Hydrogen and Deuterium Detection. Sensors 17(6):1417, INFLPR Romania. pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Martvall, V.; Klein Moberg, H.; et al. (2025). Accelerating Plasmonic Hydrogen Sensors for Inert Gas Environments by Transformer-Based Deep Learning. ACS Sensors. 10.1021/acssensors.4c02616 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Massman, W.J. (1998). A review of the molecular diffusivities of H2O, CO2, CH4, CO, O3, SO2, NH3, N2O, NO, and NO2 in air, O2 and N2 near STP. Atmospheric Environment. sciencedirect.com. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• Matuschek, M. et al. (2018). Chiral Plasmonic Hydrogen Sensors. Small 14(7), 1702990. 10.1002/smll.201702990 onlinelibrary.wiley.com. — Cited by: Plasmonic & metamaterial sensors.
• McCarthy, J.H. Jr., Cunningham, K.I., Roberts, A.A., Dietrich, J.A. (1986). Soil gas studies around hydrogen-rich natural gas wells in northern Kansas. U.S. Geological Survey Open-File Report 86-461. pubs.usgs.gov. — Cited by: Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• McInnes, D., Kampbell, D.H. (2000). The Bubble Stripping Method for Determining Dissolved Hydrogen (H2) in Well Water. Field Analytical Chemistry and Technology 4(6), 283–296, EPA/600/J-01/088. cfpub.epa.gov. — Cited by: Dissolved H2 in groundwater & formation water.
• Menon, S. K.; Kumar, A.; Mondal, S. (2025). Advancements in hydrogen gas leakage detection sensor technologies and safety measures. Clean Energy 9(1), 263–277. 10.1093/ce/zkae122 academic.oup.com. — Cited by: Palladium resistive & nanomaterial sensors.
• A. V. Milkov (2022). Molecular hydrogen in surface and subsurface natural gases: Abundance, origins and ideas for deliberate exploration. Earth-Science Reviews 230, 104063. sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Helium, noble gases & co-tracers, Isotopic & genetic fingerprinting, Dissolved H2 in groundwater & formation water.
• Milkov, A.V., Etiope, G. (2018). Revised genetic diagrams for natural gases based on a global dataset of >20,000 samples. Organic Geochemistry 125, 109–120. sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• D. Miu, R. Bîrjega, C. Viespe (2018). Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO3 Bilayers. Sensors 18(11):3636, INFLPR Romania. 10.3390/s18113636 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Miura, N.; Sato, T.; Anggraini, S.A.; Ikeda, H.; Zhuiykov, S. (2014). A review of mixed-potential type zirconia-based gas sensors. Ionics 20, 901–925. 10.1007/s11581-014-1140-1. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Molofsky, L.J. et al. (2016). Effect of Different Sampling Methodologies on Measured Methane Concentrations in Groundwater Samples. Groundwater 54(5), 669–680. 10.1111/gwat.12415. — Cited by: Dissolved H2 in groundwater & formation water.
• Moretti, I., Prinzhofer, A., Françolin, J., Rosanne, M., Rupin, F., Mertens, J. (2021). Long-term monitoring of natural hydrogen superficial emissions in a brazilian cratonic environment. Sporadic large pulses versus daily periodic emissions. International Journal of Hydrogen Energy 46(5), 3615–3628. 10.1016/j.ijhydene.2020.11.026 sciencedirect.com. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• Morita, M., Nakamura, K., Kim, J.-H. (1996). Langmuir analysis on hydrogen gas response of palladium-gate FET. Sensors and Actuators B 33, sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• A. Mujahid, A. Afzal, F. L. Dickert (2019). An Overview of High Frequency Acoustic Sensors—QCMs, SAWs and FBARs—Chemical and Biochemical Applications. Sensors 19(20):4395. 10.3390/s19204395 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Multiple Gas Detection by Cavity-Enhanced Raman Spectroscopy with Sub-ppm Sensitivity, Yang et al., Analytical Chemistry, 2023 (finesse >2500, ~1 kW circulating power from ~240 mW PDH-locked input) (2023). pubs.acs.org; author-hosted PDF: staff.ustc.edu.cn. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Muradov, N. et al. (n.d.). Methods of forming visual hydrogen detector with variable reversibility. US Patent 8,623,662 B1. patents.google.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Myagkiy, A., Moretti, I., Brunet, F. (2020). Space and time distribution of subsurface H2 concentration in so-called ‘fairy circles’: Insight from a conceptual 2-D transport model. BSGF — Earth Sciences Bulletin 191, 13. bsgf.fr; Science.org (2024 news), “How hydrogen-leaking ‘fairy circles’ might form.” science.org. — Cited by: Geologic context: the measurement problem in H2 exploration.

N

• Nahon et al. (2012). DESIRS: a state-of-the-art VUV beamline featuring high resolution and variable polarization for spectroscopy and dichroism at SOLEIL. J. Synchrotron Rad.. PubMed record: pubmed.ncbi.nlm.nih.gov. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Nauer, P.A., Chiri, E., Jirapanjawat, T., Greening, C., Cook, P.L.M. (2021). Technical note: Inexpensive modification of Exetainers for the reliable storage of trace-level hydrogen and carbon monoxide gas samples. Biogeosciences 18, 729–737. 10.5194/bg-18-729-2021 bg.copernicus.org. — Cited by: Gas chromatography (lab, micro, and field GC), Soil-gas surveys: hardware, protocols & survey design.
• Ndaya, C. C.; Javahiraly, N.; Brioude, A. (2019). Recent Advances in Palladium Nanoparticles-Based Hydrogen Sensors for Leak Detection. Sensors 19(20), 4478. 10.3390/s19204478 pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense, Fiber-optic & chemochromic hydrogen sensors, Palladium resistive & nanomaterial sensors.
• Ngo, T. A.; Magar, A. T.; Pham, M. T.; et al. (2025). Fullerene-decorated PdCo nano-resistor network hydrogen sensors with sub-second response and parts-per-billion detection at room temperature. Nature Communications 17. 10.1038/s41467-025-67708-2 pmc.ncbi.nlm.nih.gov. — Cited by: Palladium resistive & nanomaterial sensors, Environmental covariance & signal interpretation.
• Niemi, K., Schulz-von der Gathen, V., Döbele, H.F. (2001). Absolute calibration of atomic density measurements by laser-induced fluorescence spectroscopy with two-photon excitation. J. Phys. D: Appl. Phys. 34, 2330. pureadmin.qub.ac.uk. — Cited by: Why hydrogen is hard to sense.
• Nienhaus, H., Gergen, B., Weinberg, W.H., McFarland, E.W. et al. (n.d.). Detection of chemically induced hot charge carriers with ultrathin metal film Schottky contacts. Surface Science, sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Novelli, P.C., Lang, P.M., Masarie, K.A., Hurst, D.F., Myers, R., Elkins, J.W. (1999). Molecular hydrogen in the troposphere: Global distribution and budget. J. Geophys. Res. Atmos. 104(D23), 30427–30444. 10.1029/1999JD900788 agupubs.onlinelibrary.wiley.com. — Cited by: Why hydrogen is hard to sense, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• Nugroho, F. A. A.; Darmadi, I.; Cusinato, L.; Susarrey-Arce, A.; Schreuders, H.; Bannenberg, L. J.; Fanta, A. B. da Silva; Kadkhodazadeh, S.; Wagner, J. B.; Antosiewicz, T. J.; Hellman, A.; Zhdanov, V. P.; Dam, B.; Langhammer, C. (2019). Metal–polymer hybrid nanomaterials for plasmonic ultrafast hydrogen detection. Nature Materials 18, 489–495. 10.1038/s41563-019-0325-4 nature.com. — Cited by: Plasmonic & metamaterial sensors.
• Nugroho, F. A. A.; Bai, P.; Darmadi, I.; Castellanos, G. W.; Fritzsche, J.; Langhammer, C.; Gómez Rivas, J.; Baldi, A. (2022). Inverse designed plasmonic metasurface with parts per billion optical hydrogen detection. Nature Communications 13, 5737. 10.1038/s41467-022-33466-8 nature.com. — Cited by: Plasmonic & metamaterial sensors.

O

• Oliver, B.M. et al. (1984). Helium concentration in the Earth’s lower atmosphere. Geochimica et Cosmochimica Acta 48(9), 1759–1767. sciencedirect.com; ntrs.nasa.gov. — Cited by: Helium, noble gases & co-tracers, Reading a sensor datasheet.
• A. K. Ottens, W. W. Harrison, T. P. Griffin, W. R. Helms (2002). Real-Time Quantitative Analysis of H2, He, O2, and Ar by Quadrupole Ion Trap Mass Spectrometry. Analytical Chemistry. pubmed.ncbi.nlm.nih.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).

P

• Padilla, M. et al. (n.d.). Drift compensation of gas sensor array data by Orthogonal Signal Correction. Chemometrics and Intelligent Laboratory Systems. sciencedirect.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Pak, Y.; et al. (2019). Highly Stable and Ultrafast Hydrogen Gas Sensor Based on 15 nm Nanogaps Switching in a Palladium–Gold Nanoribbons Array. Advanced Materials Interfaces. 10.1002/admi.201801442 advanced.onlinelibrary.wiley.com. — Cited by: Palladium resistive & nanomaterial sensors.
• Palmisano, V., Weidner, E., Boon-Brett, L., Bonato, C., Harskamp, F., Moretto, P., Post, M.B., Burgess, R., Rivkin, C., Buttner, W.J. (2015). Selectivity and resistance to poisons of commercial hydrogen sensors. International Journal of Hydrogen Energy, 40 11740–11747. 10.1016/j.ijhydene.2015.02.120. — Cited by: Catalytic pellistors, Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Helium, noble gases & co-tracers, Reading a sensor datasheet.
• Palmisano, V., Boon-Brett, L., Bonato, C., Harskamp, F., Buttner, W.J., Post, M.B., Burgess, R., Rivkin, C. (2013). Evaluation of Selectivity of Commercial Hydrogen Sensors. Proc. International Conference on Hydrogen Safety (ICHS) 2013, JRC-IET/NREL. hysafe.info. — Cited by: Standards, regulations & certification.
• C. G. Parigger (n.d.). Self-Absorption Corrections to Hydrogen and Aluminum. Univ. of Auburn/IRAMP. auburn.edu. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Patimisco, P., Scamarcio, G., Tittel, F.K., Spagnolo, V. (2014). Quartz-Enhanced Photoacoustic Spectroscopy: A Review. Sensors 14, 6165–6206. ncbi.nlm.nih.gov. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Patino, C., Piedrahita, D., Colorado, E., Aristizabal, K., Moretti, I. (2024). Natural H2 Transfer in Soil: Insights from Soil Gas Measurements at Varying Depths. Geosciences 14(11), 296. mdpi.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors, Geologic context: the measurement problem in H2 exploration.
• Patiño, C. et al. (Ecopetrol); Strąpoć, D. (corresponding, SLB) et al. (2024). First downhole sampling of a natural hydrogen reservoir in Colombia. Frontiers in Energy Research, 19 December 2024. 10.3389/fenrg.2024.1443269 frontiersin.org. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing, Dissolved H2 in groundwater & formation water.
• Paulot, F., Pétron, G., Crotwell, A.M., Bertagni, M.B. (2024). Reanalysis of NOAA H2 observations: implications for the H2 budget. Atmospheric Chemistry and Physics 24, 4217–4229. 10.5194/acp-24-4217-2024 acp.copernicus.org. — Cited by: Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• E. R. Peck, S. Huang (1977). Refractivity and dispersion of hydrogen in the visible and near infrared. J. Opt. Soc. Am. 67(11), 1550; dispersion formula summarized via refractiveindex.info. opg.optica.org; refractiveindex.info. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Pengg, A., Misch, D., Tari, G., Sachsenhofer, R.F., Zach, C., Stranzl, C. (2025). Drilling-induced hydrogen: A challenge for natural hydrogen exploration. International Journal of Hydrogen Energy, vol. 149, art. 150091. Author list confirmed via independent cross-referencing (ResearchGate listing and Montanuniversität Leoben author-affiliation records) during 2026-07 citation verification; not directly visible on the paywalled ScienceDirect abstract page. sciencedirect.com. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• Persaud, K., Dodd, G. (1982). Analysis of discrimination mechanisms in the mammalian olfactory system using a model nose. Nature 299, 352–355. nature.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Peruski, K. M.; Vestal, B. K.; Vick, M.; Cobble, C.; Johnson, K. R.; McFarlane, J. (2023). On-line Measurement of Hydrogen Gas using Raman Spectroscopy for Process Gas Systems. ORNL/TM-2023/2949, Oak Ridge National Laboratory, July 2023. info.ornl.gov; osti.gov. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Prinzhofer, A., Tahara Cissé, C.S., Diallo, A.B. (2018). Discovery of a large accumulation of natural hydrogen in Bourakebougou (Mali). International Journal of Hydrogen Energy 43(42), 19315–19326. 10.1016/j.ijhydene.2018.08.193 sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Downhole & borehole H2 sensing, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design, Helium, noble gases & co-tracers.
• Prinzhofer, A., Moretti, I., Francolin, J., Pacheco, C., D’Agostino, A., Werly, J., Rupin, F. (2019). Natural hydrogen continuous emission from sedimentary basins: The example of a Brazilian H2-emitting structure. International Journal of Hydrogen Energy 44, 5676–5685. 10.1016/j.ijhydene.2019.01.119 sciencedirect.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.
• Privalov, V. E.; Shemanin, V. G. (2023). Lidar Measurement of the Raman Differential Cross Section by Hydrogen Molecules. Optical Memory and Neural Networks 32, 34–38. link.springer.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Q

• S. M. M. Quintero, S. W. O. Figueiredo, V. L. Takahashi, R. A. W. Llerena, A. M. B. Braga (2017). Passive Downhole Pressure Sensor Based on Surface Acoustic Wave Technology. Sensors 17(7):1635, PUC-Rio, Shell Brazil-funded. pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

R

• Rahn, T., Eiler, J.M., Boering, K.A. et al. (2003). Extreme deuterium enrichment in stratospheric hydrogen and the global atmospheric budget of H2. Nature 424, 918–921. nature.com. — Cited by: Isotopic & genetic fingerprinting.
• Ramaiyan, K.P.; Mukundan, R. (2020). Editors’ Choice—Review—Recent Advances in Mixed Potential Sensors. J. Electrochem. Soc. 167, 037547. osti.gov. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Range Complex / U.S. Army Environmental Command (2001). Soil Gas Survey Introduction. (Camp Stanley Storage Activity, TX). stanley.army.mil. — Cited by: Soil-gas surveys: hardware, protocols & survey design.
• D. Rapp and P. Englander-Golden (1965). Total Cross Sections for Ionization and Attachment in Gases by Electron Impact. I. Positive Ionization. J. Chem. Phys. 43, 1464. dydaktyka.fizyka.umk.pl%201464.pdf. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Recum, P., Hirsch, T. (2024). Graphene-based chemiresistive gas sensors. Nanoscale Advances, RSC. 10.1039/D3NA00423F pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Reid, J., Labrie, D. (1981). Second-harmonic detection with tunable diode lasers — Comparison of experiment and theory. Appl. Phys. B 26, 203–210. link.springer.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Reji, L., Bertagni, M.B., Paulot, F., Qin, Q., Zhang, X. (2025). Global implications of a low soil moisture threshold for microbial hydrogen uptake. Nature Communications. 10.1038/s41467-025-67208-3 pmc.ncbi.nlm.nih.gov. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.
• Roberson, L., Captain, J., Williams, M., Smith, T., Tate, L.C. (2012). Chemochromic detector for sensing gas leakage and process for producing the same. US Patent 8,293,178 B2. image-ppubs.uspto.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.

S

• Saffell, J.R., Martin, N.A. (2024). Measurements of the Limit of Detection for Electrochemical Gas Sensors. Journal of Testing and Evaluation 52(5), 2675–2684. 10.1520/JTE20230675. — Cited by: Reading a sensor datasheet, How the sensor families actually differ: a transduction decoder, Figures of merit: how to compare any two H2 sensors honestly.
• Salter, R.; Chu, J.; Hippler, M. (2012). Cavity-enhanced Raman spectroscopy with optical feedback cw diode lasers for gas phase analysis and spectroscopy. Analyst 137(20), 4669–4676. pubs.rsc.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Sander, R. (2015). Compilation of Henry’s law constants (version 4.0) for water as solvent. Atmospheric Chemistry and Physics 15, 4399–4981. 10.5194/acp-15-4399-2015 acp.copernicus.org. — Cited by: Gas-phase vs. aqueous-phase H2 sensing.
• Sano, Y., Wakita, H. (1985). Geographical Distribution of ³He/⁴He Ratios in Japan. eri.u-tokyo.ac.jp. — Cited by: Helium, noble gases & co-tracers.
• Sauerbrey, G. (1959). Verwendung von Schwingquarzen zur Wägung dünner Schichten und zur Mikrowägung. Zeitschrift für Physik 155(2), 206–222. — Cited by: How the sensor families actually differ: a transduction decoder, Figures of merit: how to compare any two H2 sensors honestly.
• Saunders, L. & Horrocks, B. R. (2025). Review—Aspects of Electrochemical Gas Sensor Technologies. ECS Sensors Plus 4(3), 034601. 10.1149/2754-2726/adf2b9. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Schedin, F., Geim, A.K., Morozov, S.V., Hill, E.W., Blake, P., Katsnelson, M.I., Novoselov, K.S. (2007). Detection of individual gas molecules adsorbed on graphene. Nature Materials 6, 652–655. 10.1038/nmat1967 nature.com. — Cited by: 2D-material & nanostructure FET sensors.
• Schrötter, H. W.; Klöckner, H. W. (1979). Raman Scattering Cross Sections in Gases and Liquids. In Raman Spectroscopy of Gases and Liquids (Topics in Current Physics, vol. 11), ed. A. Weber, Springer, Berlin/Heidelberg, 1979, pp. 123–166. link.springer.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Sekhar, P.K.; Brosha, E.L.; Mukundan, R.; Nelson, M.A.; Garzon, F.H. (2009). Application of Commercial Automotive Sensor Manufacturing Methods for NOx/NH3 Mixed Potential Sensors for Emission Control. ECS Trans. 19, 45–49. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Shegai, T.; Johansson, P.; Langhammer, C.; Käll, M. (2012). Directional Scattering and Hydrogen Sensing by Bimetallic Pd–Au Nanoantennas. Nano Letters 12(5), 2464–2469. 10.1021/nl300558h pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• M. Singleton and G. Hudson (2005). Membrane Inlet Mass Spectrometry for Measuring Dissolved Gases. Lawrence Livermore National Laboratory Technical Report, OSTI ID 877829. 10.2172/877829. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Dissolved H2 in groundwater & formation water.
• Singor, A. J. C.; Scarlett, L. H.; Zammit, M. C.; Bray, I.; Fursa, D. V. (2024). Rovibrationally resolved Rayleigh and Raman scattering cross sections for molecular hydrogen. J. Chem. Phys. 161, 244304. 10.1063/5.0235703 pubs.aip.org; PubMed: pubmed.ncbi.nlm.nih.gov. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Snavely, K. & Subramaniam, B. (1998). Thermal Conductivity Detector Analysis of Hydrogen Using Helium Carrier Gas and HayeSep® D Columns. Journal of Chromatographic Science 36(4), 191. academic.oup.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC), Calibration, drift & QA/QC for H2 field programs, Helium, noble gases & co-tracers.
• Somogyi, W., Yurchenko, S.N., Yachmenev, A. (2021). Calculation of electric quadrupole linestrengths for diatomic molecules: Application to the H2, CO, HF and O2 molecules. J. Chem. Phys. 155, 214303. 10.1063/5.0063256 pubs.aip.org. — Cited by: Why hydrogen is hard to sense, IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, How the sensor families actually differ: a transduction decoder.
• Song, J., Lu, W., Flynn, J.S., Brandes, G.R. (2005). Pt−AlGaN/GaN Schottky diodes operated at 800 °C for hydrogen sensing. Applied Physics Letters 87, 133501, DOI 10.1063/1.2058227. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Sood, S. et al. (2020). Development and test of a highly sensitive and selective hydrogen sensor system. J. Sens. Sens. Syst. 9, 309–317. 10.5194/jsss-9-309-2020. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Spalding, B.P., Watson, D.B. (2006). Measurement of dissolved H2, O2, and CO2 in groundwater using passive samplers for gas chromatographic analyses. Environmental Science & Technology 40(24), 7861–7867. pubmed.ncbi.nlm.nih.gov. — Cited by: Dissolved H2 in groundwater & formation water.
• Spear, J.R., Walker, J.J., McCollom, T.M., Pace, N.R. (2005). Hydrogen and bioenergetics in the Yellowstone geothermal ecosystem. Proceedings of the National Academy of Sciences 102(7), 2555–2560. 10.1073/pnas.0409574102. — Cited by: Dissolved H2 in groundwater & formation water.
• Stolper, D.A. et al. (2014). Formation temperatures of thermogenic and biogenic methane. Science 344(6191), 1500–1503. science.org. — Cited by: Isotopic & genetic fingerprinting.
• Strapoc, D., Ammar, M., Abolins, N., Gligorijevic, A. (2022). Key Role of Regearing Mud Gas Logging For Natural H2 Exploration. SPWLA 63rd Annual Logging Symposium, SPWLA-2022-0008. onepetro.org. — Cited by: Gas chromatography (lab, micro, and field GC), Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing, Standards, regulations & certification.
• Strapoc, D., Abolins, N.I., Ammar, M., Gligorijevic, A., Suarez, J., Fowlow, H. (Schlumberger). (2023). Mud logging of natural hydrogen. Patent WO2023192219A1, filed March 28, 2023, published October 5, 2023. patents.google.com. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing.
• R. L. Summers (1969). Empirical Observations on the Sensitivity of Hot Cathode Ionization Type Vacuum Gauges. NASA Technical Report NASA-TN-D-5285, as cited/tabulated in [2]. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• U.S. Geological Survey (2024). The Potential for Geologic Hydrogen for Next-Generation Energy. usgs.gov. — Cited by: Geologic context: the measurement problem in H2 exploration.
• Sutapun, B., Tabib-Azar, M. & Kazemi, A. (1999). Pd-coated elastooptic fiber optic Bragg grating sensors for multiplexed hydrogen sensing. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.

T

• Tanichev, A. S.; Petrov, D. V. (2025). Helium Detection in Natural Gas Using Raman Spectroscopy. Applied Spectroscopy 79(5), 784–796. 10.1177/00037028241282669 pubmed.ncbi.nlm.nih.gov. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Thapa, J.; Buric, M. P.; Chorpening, B. T. (2025). Real-time hydrogen gas blend composition measurement with waveguide-enhanced Raman gas analyzer. Proc. SPIE 13467, Optical Waveguide and Laser Sensors IV, 134670G. 10.1117/12.3053587 spiedigitallibrary.org. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• N. H. Thomas et al. (2018). Characterization of Hydrogen in Basaltic Materials With Laser-Induced Breakdown Spectroscopy (LIBS) for Application to MSL ChemCam Data. J. Geophys. Res. Planets 123(8). agupubs.onlinelibrary.wiley.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Tomeček, D.; Klein Moberg, H.; Nilsson, S.; Theodoridis, A.; Darmadi, I.; Midtvedt, D.; Volpe, G.; Andersson, O.; Langhammer, C. (2024). Neural network enabled nanoplasmonic hydrogen sensors with 100 ppm limit of detection in humid air. Nature Communications 15, 1208. 10.1038/s41467-024-45484-9 pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Plasmonic & metamaterial sensors.

V

• Vergara, A., Vembu, S., Ayhan, T., Ryan, M.A., Homer, M.L., Huerta, R. (2012). Chemical gas sensor drift compensation using classifier ensembles. Sensors and Actuators B: Chemical 166–167, 320–329. 10.1016/j.snb.2012.01.074. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Vroblesky, D.A. (n.d.). A simple pore water hydrogen diffusion syringe sampler. U.S. Geological Survey. usgs.gov; ncbi.nlm.nih.gov. — Cited by: Dissolved H2 in groundwater & formation water.

W

• Wadell, C.; Nugroho, F. A. A.; Lidström, E.; Iandolo, B.; Wagner, J. B.; Langhammer, C. (2015). Hysteresis-Free Nanoplasmonic Pd–Au Alloy Hydrogen Sensors. Nano Letters 15(5), 3563–3570. 10.1021/acs.nanolett.5b01053 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• W. Wang, X. Liu, S. Mei, M. Liu, C. Lu, M. Lu (2019). Development of a High Stability Pd-Ni Alloy Thin-Film Coated SAW Device for Sensing Hydrogen. Sensors 19(16):3560. 10.3390/s19163560 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Wang, P.; Chen, W.; Wang, J.; Zhou, F.; Hu, J.; Zhang, Z.; Wan, F. (2021). Hazardous Gas Detection by Cavity-Enhanced Raman Spectroscopy for Environmental Safety Monitoring. Anal. Chem. 93(46), 15474–15481. 10.1021/acs.analchem.1c03499. — Cited by: Raman spectroscopy (spontaneous, gas phase).
• Wang, R.; Zhang, X.; et al. (2025). Stabilizing PdAu hydrogen sensors: Mechanistic insights into metastable PdO and dual strategies of refresh and plasma treatment. Chemical Engineering Journal 514, 163420. sciencedirect.com. — Cited by: Palladium resistive & nanomaterial sensors.
• Wenger, L.M., Pottorf, R.J., Macleod, G., Otten, G., Dreyfus, S., Justwan, H., Wood, E.S. (2009). Drill-Bit Metamorphism: Recognition and Impact on Show Evaluation. SPE-125218-MS, SPE Annual Technical Conference and Exhibition, New Orleans, 2009. onepetro.org. — Cited by: Mud-gas logging for H2 while drilling.
• Werle, P., Mücke, R., Slemr, F. (1993). The limits of signal averaging in atmospheric trace-gas monitoring by tunable diode-laser absorption spectroscopy (TDLAS). Applied Physics B 57, 131–139. link.springer.com. — Cited by: Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.
• Whiticar, M.J. (1999). Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane. Chemical Geology 161, 291–314. sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Wiersberg, T. et al. (2007). A helium isotope cross-section study through the San Andreas Fault at seismogenic depths. Geochemistry, Geophysics, Geosystems 8(6). agupubs.onlinelibrary.wiley.com. — Cited by: Isotopic & genetic fingerprinting.
• Wörner, J., Eimler, J., Pein-Hackelbusch, M. (2025). Long-term drift behavior in metal oxide gas sensor arrays: a one-year dataset from an electronic nose. Scientific Data 12, 1628. 10.1038/s41597-025-05993-8 pmc.ncbi.nlm.nih.gov. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

X

• Xiao, M., Liang, S., Han, J., Zhong, D., Liu, J., Zhang, Z., Peng, L. (2018). Batch Fabrication of Ultrasensitive Carbon Nanotube Hydrogen Sensors with Sub-ppm Detection Limit. ACS Sensors 3(4), 749–756. 10.1021/acssensors.8b00006 pubs.acs.org. — Cited by: 2D-material & nanostructure FET sensors.
• Xu, F., Li, L., Jing, P., Yu, Z., Zhang, J., Liu, S. (2024). Experimental Study on the Characterization of Aging Resistance Properties of Optical Cables in the Hydrogen-Containing Downhole Environment. Sensors 24(5), 1655. 10.3390/s24051655 pmc.ncbi.nlm.nih.gov. — Cited by: Downhole & borehole H2 sensing.

Y

• Yamazoe, N.; Shimanoe, K. (2008). Theory of power laws for semiconductor gas sensors. Sensors and Actuators B: Chemical 128(2), 566–573. 10.1016/j.snb.2007.07.036 sciencedirect.com. — Cited by: Metal-oxide (MOX) chemiresistors, Figures of merit: how to compare any two H2 sensors honestly.
• Yan, S., Cao, Y., Su, Y., Huang, B., Chen, C., Yu, X., Xu, A., Wu, T. (2025). Hydrogen Sensors Based on Pd-Based Materials: A Review. Sensors 25(11), 3402. 10.3390/s25113402 pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense, Fiber-optic & chemochromic hydrogen sensors, Palladium resistive & nanomaterial sensors, Environmental covariance & signal interpretation.
• Yang, et al. (2025). H2S Sensing with SnO2-Based Gas Sensors: Sulfur Poisoning Mechanism Revealed by Operando DRIFTS and DFT Calculations. Angewandte Chemie International Edition. PMC12124429. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors, Solid-electrolyte & high-temperature electrochemical sensors.
• Ye, Z., Liu, Y., Li, Q. (2021). Recent Progress in Smart Electronic Nose Technologies Enabled with Machine Learning Methods. Sensors 21(22), 7620. 10.3390/s21227620 pmc.ncbi.nlm.nih.gov. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Yunusa, Z., Hamidon, M.N., Kaiser, A., Awang, Z. (2014). Gas Sensors: A Review. Sensors & Transducers, Vol. 168, Issue 4, April 2014, pp. 61–75. sensorsportal.com. — Cited by: Catalytic pellistors.
• Z. Yunusa, M. N. Hamidon, A. Ismail, M. Mohd Isa, M. H. Yaacob, S. Rahmanian, S. A. Ibrahim, A. A. A. Shabaneh (2015). Development of a Hydrogen Gas Sensor Using a Double SAW Resonator System at Room Temperature. Sensors 15(3):4749. 10.3390/s150304749 pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Yver, C., Schmidt, M., Bousquet, P., Ramonet, M. (2011). Measurements of molecular hydrogen and carbon monoxide on the Trainou tall tower. Tellus B: Chemical and Physical Meteorology 63(2) (seasonal amplitude ~45 ppb, nighttime depletion, radon-tracer-method deposition velocity ~2.6×10⁻² cm/s). 10.1111/j.1600-0889.2010.00520.x b.tellusjournals.se. — Cited by: Environmental covariance & signal interpretation.

Z

• Zhai, Z., Liu, Y., Li, C., Wang, D., Wu, H. (2024). Electronic Noses: From Gas-Sensitive Components and Practical Applications to Data Processing. Sensors 24(15), 4806. 10.3390/s24154806 pmc.ncbi.nlm.nih.gov. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• H. Zhang et al. (2023). 1ppm-detectable hydrogen gas sensors by using highly sensitive P+/N+ single-crystalline silicon thermopiles. Microsystems & Nanoengineering, nature.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Zhang, W., Hu, S., Zhang, Z., Zheng, Y., Wang, Q.J., Lin, Z. (2024). Unsupervised Attention-Based Multi-Source Domain Adaptation Framework for Drift Compensation in Electronic Nose Systems. arXiv:2409.13167. arxiv.org. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Zhu, Z., Liu, C., Jiang, F., Liu, J., Ma, X., Liu, P., Xu, J., Wang, L., Huang, R. (2020). Flexible and lightweight Ti3C2Tx MXene@Pd colloidal nanoclusters paper film as novel H2 sensor. Journal of Hazardous Materials 399, 123054. 10.1016/j.jhazmat.2020.123054 sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors.

Standards, datasheets & web resources

Works with no personal author — standards, vendor datasheets, product and application notes, encyclopedic and other web resources — grouped by issuing organization.

AAPG Explorer

• Does This Finally Settle the Age-Old Debate over Abiotic Methane? (2022). aapg.org (argues the reversed δ¹³C ordering reflects high thermal maturity, not abiogenesis). — Cited by: Isotopic & genetic fingerprinting.

AAPG Wiki

• Density-neutron log porosity. wiki.aapg.org. — Cited by: Downhole & borehole H2 sensing.
• Mudlogging: gas extraction and monitoring. wiki.aapg.org. — Cited by: Catalytic pellistors, Mud-gas logging for H2 while drilling.

ABB

• Katharometers Series 6517. library.e.abb.com (title/series confirmed; PDF text not machine-readable in this session). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• OA-ICOS Laser Gas Analyzers — LGR-ICOS Technology. new.abb.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Academia.edu

• An ultrasonic sensor for the analysis of binary gas mixtures. academia.edu (title-level reference). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Acoustical Society of America

• press summary of Garrett sonic gas analyzer, acoustics.org (fetched 2026-07-04); resonance frequency stability ~0.02 Hz / ~30 ppm resolution and <350 ppm system stability figures via search synthesis of the same work (ScienceDaily, sciencedaily.com phys.org, phys.org). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

ACS Publications

• Comparison of Experimental vs Theoretical Abundances of 13CH3D and 12CH2D2 for Isotopically Equilibrated Systems from 1 to 500 °C. ACS Earth and Space Chemistry (2019). pubs.acs.org. — Cited by: Isotopic & genetic fingerprinting.

Aeris Technologies

• MIRA Pico. aerissensors.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Agilent Technologies

• 990 Mobile Micro GC User Manual / datasheet. agilent.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Helium Impurity Analysis Using the Agilent 990 Micro GC. Application Note 5994-2140EN. agilent.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Hydrogen Detection with a TCD using Mixed Carrier Gas on the Agilent Micro GC. Application Note 5991-3199EN. gcms.labrulez.com; original agilent.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC), Mud-gas logging for H2 while drilling.
• Hydrogen Impurity Analysis Using the Agilent 990 Micro GC. Application Note 5994-2138EN. agilent.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Switch to Hydrogen or Nitrogen as Alternate Carrier Gas. agilent.com (page concerns converting from helium to hydrogen or nitrogen carrier gas; does not discuss switching to argon for accurate H2/He quantification). — Cited by: Helium, noble gases & co-tracers.
• 490 Micro GC Natural Gas Analyzers, datasheet 5991-0301EN and application note 5991-0275EN (µTCD, requires argon carrier for He/Ne/H2). agilent.com; agilent.com. — Cited by: Helium, noble gases & co-tracers.

AGU (American Geophysical Union)

• Modeling the photochemical origins of the extreme deuterium enrichment in stratospheric H2. Journal of Geophysical Research: Atmospheres (2007). agupubs.onlinelibrary.wiley.com. — Cited by: Isotopic & genetic fingerprinting.

Air Liquide UK

• ALPHAGAZ speciality gases and calibration mixtures. uk.airliquide.com; “Calibration and analysis.” uk.airliquide.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.

AirGradient

• Krause, A.; Brooke, E. How Accurate is the Sensirion SGP41 TVOC Sensor? (Dec. 10, 2024). airgradient.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

Airpressa

• What is Nm3? How is It Different from m3? (Nm³/scf reference-condition variability). airpressa.com (states only the single 0 °C/1 atm convention). — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.

Alkor

• Lithium Fluoride LiF windows and lenses. (~40% transmission at 121 nm). alkor.net. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Alphasense Ltd

• Hydrogen Sensors (H2). product line and H2-AF specification. alphasense.com; store.alphasense.com; co2meter.com. — Cited by: Why hydrogen is hard to sense, Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.

American Petroleum Institute (API)

• API RP 500: 4th Edition announcement; API RP 505 record (classification of locations at petroleum facilities). api.org. — Cited by: Standards, regulations & certification.

AMETEK

• ta3000R Reduction Gas Analyzer — Specifications. asap.nl. — Cited by: Gas chromatography (lab, micro, and field GC), Dissolved H2 in groundwater & formation water.

Amphenol Advanced Sensors

• Gas Sensor Measurement Setup: How to Get Accurate Data. blog.amphenol-sensors.com. — Cited by: Reading a sensor datasheet.

AMS, Inc

• Gas Vapor Probe Retract-A-Tip. product page (materials, tubing dimensions, SKU 210.01, price). ams-samplers.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Analog Devices

• Overcoming the Technical Challenges of Electrochemical Gas Sensing. analog.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

ANCORP

• Magnesium Fluoride (MgF2) Viewports. ancorp.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Archer Materials Biochip

• Archer Materials completes proof-of-concept biochip graphene sensor technology. Graphene-Info, graphene-info.com. — Cited by: 2D-material & nanostructure FET sensors.

ARPA-E

• H2SENSE Exploratory Topic — Project Descriptions. arpa-e.energy.gov. — Cited by: Plasmonic & metamaterial sensors.

Aryballe

• NeOse Advance, product page. aryballe.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

ASTM International

• D1945-14(2019) Standard Test Method for Analysis of Natural Gas by Gas Chromatography (He, H2, O2, N2, CO2, hydrocarbons, H2S). astm.org; h2tools.org. — Cited by: Helium, noble gases & co-tracers.

Axetris (Leister Group)

• OEM Gas Sensing Module LGD Compact-A Series — Product Datasheet Rev J. cdn-assets.leister.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Axiom Sensing

• Home / Soil Gas Survey Services (WHALI system description). axiomsensing.com; axiomsensing.com. — Cited by: Geologic context: the measurement problem in H2 exploration.
• WHALI/EVA autonomous logger system description and field-deployment figures. axiomsensing.com; researchgate.net. — Cited by: Environmental covariance & signal interpretation.

AZoM / tec5USA

• Using In-Line Raman Spectroscopy for Natural Gas Monitoring. azom.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

AZoOptics

• Vacuum Ultraviolet Monochromator - Model 234/302 from McPherson. azooptics.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Baker Hughes

• Hydrogen purity in hydrogen-cooled generators. bakerhughes.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Baker Hughes / Panametrics

• XMTCpro. bakerhughes.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Balluff

• How to understand the difference between resolution, accuracy, and repeatability / precision. balluff.com. — Cited by: Reading a sensor datasheet.

BeamQ Laser

• Excimer lasers 193 nm, 248 nm, 308 nm, and 351 nm. product listing (~$195,000). beamq.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Blackline Safety

• Pellistor (Catalytic Bead) Sensor Technical Notes. Live URL now redirects to the help-center homepage (link dead as of 2026-07); archived copy: web.archive.org. — Cited by: Catalytic pellistors.

Bosch

• BME688 4-in-1 environmental sensor unit with AI. product flyer BST-BME688-FL000. bosch-sensortec.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• Sensors for fuel cell-electric systems. bosch-mobility.com. — Cited by: Palladium resistive & nanomaterial sensors.
• BME688 gas sensor: datasheet (BST-BME688-DS000), product page, and BME AI-Studio documentation. bosch-sensortec.com; bosch-sensortec.com; bosch-sensortec.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

BSEE

• Hydrogen Sulfide (H2S) — IDLH and alarm thresholds. bsee.gov; bsee.gov. — Cited by: Helium, noble gases & co-tracers.

C2Sense

• C2Sense wins award for ‘Selective CNT Gas Sensors’. Safar Partners, safar.partners; MIT STEX profile, startupexchange.mit.edu. — Cited by: 2D-material & nanostructure FET sensors.

Cambridge University Press

• Ammonium fixation during illite-smectite diagenesis in Upper Jurassic shale, North Sea. Clay Minerals, Cambridge Core. cambridge.org. — Cited by: Helium, noble gases & co-tracers.

CCOHS

• Converting Occupational Exposure Limits from mg/m³ to ppm (ppm = mg/m³ × 24.45 / MW). ccohs.ca. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.

CEA-Leti

• Aryballe offers a universal electronic nose, news article. leti-cea.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

Chemistry LibreTexts

• Standard Reduction Potential (O2 + 4H⁺ + 4e⁻ → 2H2O, E° = +1.229 V vs. SHE at 25 °C). chem.libretexts.org. — Cited by: How the sensor families actually differ: a transduction decoder.

Chromatotec

• CHROMA DID. product page. chromatotec.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• ChromaTCD Permanent Gases Analyzer. product page. chromatotec.com. — Cited by: Gas chromatography (lab, micro, and field GC).

Chromservis

• GA5000 analyser for measurement of CH4/CO2/O2/H2 (1000 ppm), bluetooth. Product page. chromservis.eu. — Cited by: Electrochemical cells (amperometric & potentiometric).

Clairair Ltd

• A Discussion on Pellistor Gas Sensor Responses. clairair.co.uk (mirror: chromatographytoday.com). — Cited by: Catalytic pellistors.

Critical Environment Technologies

• Electrochemical Gas Sensors & Factors Affecting Life Expectancy. critical-environment.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Crowcon Detection Instruments

• Knowing Cross Sensitivities. crowcon.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Crystran

• Magnesium Fluoride MgF2 - Optical Materials. crystran.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

CSA Group

• An overview of CSA Group standards, codes, and activities for the hydrogen ecosystem. csagroup.org. — Cited by: Standards, regulations & certification.

DD-Scientific

• GS+7H2 Hydrogen (H2) Sensor. Product page. ddscientific.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Del Mar Photonics

• LiF windows VUV grade. (transmission at Lyman-alpha, solarization/color-center degradation). delmarphotonics.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Desert Mountain Energy

• Desert Mountain Energy Advances Helium and Hydrogen Opportunities and Partnerships. PR Newswire. prnewswire.com. — Cited by: Helium, noble gases & co-tracers.

DetecTape

• detectape.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.

DieselNet

• NOx Sensors. technical reference page. dieselnet.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

DigiKey

• Bosch Sensortec BME688 product/pricing listing. digikey.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• STC31/STC31-C product listings, digikey.com and digikey.com (prices via search synthesis: STC31-C-R3 $33.41, STC31-C-R5 $23.91, STC31-R3 $64.25). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Posifa PGS1000/PGS1004 listing and specifications, digikey.com (fetched 2026-07-04): I2C interface, −25 to 85 °C, 4.75–5.25 V, 8 mA, ±6% accuracy, $35–45 (1–100 unit price breaks). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

DirectIndustry eMagazine

• Affordable Handheld Device Allows Analysis of Lithium in Soils and Minerals. (context on handheld LIBS/portable analyzer pricing, €40,000–55,000 range for specialized units). emag.directindustry.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Distran

• Ultrasound Imaging Technology for Gas Leak Detection. and company technology pages. distran.swiss; distran.swiss. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Dräger

• Catalytic Ex Sensors. product page. draeger.com. — Cited by: Catalytic pellistors.
• X-am 8000. product page and “Sensor XXS H2 HC 0-4 Vol.-%” product listing. draeger.com; hazmatresource.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Drilling Manual

• Drilled Gas In Mud Logging. (mud logging unit equipment and formation gas). drillingmanual.com. — Cited by: Mud-gas logging for H2 while drilling.

drillingforgas.com

• Mud Log Gas (background, drilled, swab, connection, trip). drillingforgas.com (does not support the lag-time/pump-stroke/lag-marker claim). — Cited by: Mud-gas logging for H2 while drilling.

DURRIDGE

• RAD7 Radon Detector, and RAD7 Product Brief. durridge.com; durridge.com (vendor page currently states 0.1–20,000 pCi/L). — Cited by: Helium, noble gases & co-tracers.
• Soil Gas Probes. durridge.com. — Cited by: Helium, noble gases & co-tracers.

E/One Utility Systems

• Hydrogen Gas Purity Analyzer (Generator Gas Analyzer, GGA). eone.com (fetched 2026-07-04). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

EAS Laboratories

• Tedlar Bag Information. easlab.com (does not support the claim). — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Eastern Controls, Inc

• Kaiser Optical RamanRXn1 Analyzer. easterncontrols.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Eaton (MTL)

• K1550 hydrogen/helium/argon/xenon gas analyser and general gas analyser brochure, eaton.com and mtl-inst.com (title-level). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• K522 Thermal Conductivity (TCD) Gas Sensor for Hydrogen (H2), Helium (He), Nitrogen and Argon. mtl-inst.com and eaton.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Thermal conductivity & acoustic (speed of sound) sensors, Helium, noble gases & co-tracers.

Eawag

• A Mass Spectrometric System for the Analysis of Noble Gases and Tritium in Water. eawag.ch. — Cited by: Isotopic & genetic fingerprinting.

EC Sense

• ES4-H2-1000-01 Hydrogen Gas Sensor Datasheet V1.4. (2025-02-28). ecsense.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• ES4-H2-5000-01 Hydrogen Gas Sensor Datasheet V1.4. (2025-02-28). ecsense.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Edge Impulse

• Sniffing Out Industrial Chemicals Using tinyML. edgeimpulse.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

Edmund Optics

• 532 nm, 25 mm Dia, OD 6.0 Blocking Notch Filter. (representative notch-filter spec). edmundoptics.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Electronics Cooling

• The Thermal Conductivity of Gases. electronics-cooling.com. — Cited by: Gas chromatography (lab, micro, and field GC).

Elementar

• isoprime precisION stable isotope mass spectrometer, product page. elementar.com. — Cited by: Isotopic & genetic fingerprinting.

Emerson

• Hydrogen Measurement with Ultrasonic Flow Meters. emerson.com (title-level via search). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• UV/IRS-H2 & UVS-H2 Flame Detectors. product data sheet BCR-0040-00-011; Instrumart product listing. instrumart.com; datasheet: instrumart.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Endress+Hauser

• Hydrogen-enriched gas measurement with ultrasonic flowmeters. endress.com FLOWSIC610 product info via us.endress.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Raman Rxn5 process analyzer. and “Raman Rxn2 analyzer” product/technical-information pages. us.endress.com; endress.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).

ENGIE Innovation

• PARHyS. (Permanent Analyses of Renewable Hydrogen with Sensors). innovation.engie.com; hnatsummit.com (link dead — domain does not resolve). — Cited by: Geologic context: the measurement problem in H2 exploration.

ENGIE Research & Innovation

• Is natural hydrogen of the ‘fairy circles’ the new eldorado?. (PARHyS deployment description, ~100 units, São Francisco basin, Brazil). innovation.engie.com. — Cited by: Environmental covariance & signal interpretation.

Engineering ToolBox

• Hydrogen - Thermophysical Properties. (thermal conductivity, sound velocity). engineeringtoolbox.com. — Cited by: Why hydrogen is hard to sense.

Entech Instruments

• SUMMA Canisters. product page. entechinst.com (does not support the claim). — Cited by: Soil-gas surveys: hardware, protocols & survey design.

ENVCO Global

• AMS Retract-A-Tip. catalog page (retract mechanism, mesh-screen description, reuse/decontamination). envcoglobal.com; AMS, Inc. “Gas Vapor Probe Samplers” overview. ams-samplers.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Environics

• Gas Dilution - Gas Divider Systems, Series 4040. environics.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.

Environmental Science & Technology Ltd

• LEL Correction Factor Guide. (RAE Systems LEL-1/LEL-2 sensor data) — unverified against a primary RAE Systems source; RAE’s own Technical Note TN-156 shows different hydrogen correction factors under different product-family names, and no “LEL-1”/“LEL-2” cartridge naming was located. environst.com. — Cited by: Catalytic pellistors.

ETI Geochemistry

• Helium and Hydrogen Soil Gas Anomalies Associated with Deep or Active Faults. eti-geochemistry.com. — Cited by: Helium, noble gases & co-tracers.

Evikon MCI

• %LEL, %LFL, % vol, ppm – different units in gas detection. (H2 LEL ≈4% confirmed on this page; UEL ≈75–77% does not appear on this page). evikon.eu. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.

Excellence Logging (Exlog)

• Fluid Logging. service page. exlog.com. — Cited by: Mud-gas logging for H2 while drilling.

EXREG

• ATEX Categories 1, 2, 3 & EPL (Ga/Gb/Gc) Explained. ex-reg.com. — Cited by: Standards, regulations & certification.

Extorr

• Introduction to Residual Gas Analyzers. extorr.com (does not itself state helium’s 24.6 eV ionization potential or discuss m/z=4 specifically). — Cited by: Helium, noble gases & co-tracers.

Fibercore/Humanetics

• Fiber Optic Sensing for Downhole Monitoring in Oil & Gas. (hydrogen darkening, hermetic/carbon coatings, temperature ratings). fibercore.humaneticsgroup.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Calibration, drift & QA/QC for H2 field programs, Downhole & borehole H2 sensing.

Figaro Engineering

• TGS 2600 – for the detection of Air Contaminants. product information sheet. figaro.co.jp. — Cited by: Metal-oxide (MOX) chemiresistors, Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.
• TGS 2616-C01 – for the detection of Hydrogen. product information sheet. figarosensor.comrev00.pdf. — Cited by: Metal-oxide (MOX) chemiresistors.
• TGS 821 – Special Sensor for Hydrogen Gas. product datasheet. figarosensor.com. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, How the sensor families actually differ: a transduction decoder.
• TGS6812-D00. product page. figarosensor.com. — Cited by: Catalytic pellistors.
• TGS8100. product datasheet. figarosensor.com.pdf. — Cited by: Metal-oxide (MOX) chemiresistors.
• TGS 6812 and FECS-H20 Catalytic and TGS 2616 MOS Hydrogen sensors and their application. sensor-test.de. — Cited by: Metal-oxide (MOX) chemiresistors.
• General Information for TGS Sensors: Technical Information on Usage of TGS Sensors for Toxic and Explosive Gas Leak Detectors. electronicaembajadores.com. — Cited by: Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.

Firebird Optics

• Magnesium Fluoride (MgF2) Viewports for Vacuum Systems. firebirdoptics.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Fluke

• ii910 Acoustic Imaging Camera: Precision Acoustic Imager. product page and technical datasheet. fluke.com; datasheet: fluke-direct.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Fraunhofer IPM

• Raman spectroscopy on gases. “Sensors for safe use of hydrogen” (TransHyDE project hydrogen Raman sensor). ipm.fraunhofer.de; ipm.fraunhofer.de. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Frontiers

• Review: Influences of Semiconductor Metal Oxide Properties on Gas Sensing Characteristics. frontiersin.org. — Cited by: Why hydrogen is hard to sense.
• A Review of H2, CH4, and Hydrocarbon Formation in Experimental Serpentinization Using Network Analysis. Frontiers in Earth Science (2020). frontiersin.org. — Cited by: Helium, noble gases & co-tracers.
• The Use of Noble Gases to Constrain Subsurface Fluid Dynamics / Using Radiogenic Noble Gases to Trace the Conditions of Crustal Fluid Migration. Frontiers in Earth Science (2022). frontiersin.org; sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• An Improved Cr-EA-IRMS Method for the Effective Determination of the Hydrogen Isotopes in Coal Samples. Frontiers in Chemistry (2022), PMC9021440. pmc.ncbi.nlm.nih.gov. — Cited by: Isotopic & genetic fingerprinting.
• H2 Kinetic Isotope Fractionation Superimposed by Equilibrium Isotope Fractionation During Hydrogenase Activity of D. vulgaris Strain Miyazaki. Frontiers in Microbiology (2019), PMC6636216. pmc.ncbi.nlm.nih.gov (supports the kinetic+equilibrium superposition claim; does not support the two-orders-of-magnitude carbon-KIE comparison). — Cited by: Isotopic & genetic fingerprinting.
• Analysis of safety technical standards for hydrogen storage in fuel cell vehicles. Frontiers in Energy Research (2024). frontiersin.org. — Cited by: Standards, regulations & certification.

FuelCellsWorks

• Insplorion Secures Three New Orders for NPS-P2 Hydrogen Sensors. (Oct 2024). fuelcellsworks.com. — Cited by: Plasmonic & metamaterial sensors.
• Gold Hydrogen Confirms Up to 97% Purity at Ramsay 3 Well as South Australia Drilling Completes. fuelcellsworks.com. — Cited by: Mud-gas logging for H2 while drilling.
• Insplorion and MannTek Sign LOI to Integrate Hydrogen Sensing Tech Into Refueling Nozzles. (Oct 2025). fuelcellsworks.com. — Cited by: Plasmonic & metamaterial sensors.
• Insplorion to Sell Hydrogen Sensor Business to Manntek. (March 2026). fuelcellsworks.com. — Cited by: Plasmonic & metamaterial sensors.

FUTEK

• Sensor Resolution vs Accuracy vs Repeatability. futek.com. — Cited by: Reading a sensor datasheet.

Gasmet Technologies Oy

• DX4000 FTIR Gas Analyzer Technical Data v1.6. anatrac.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• GT6000 Mobilis – Portable Gas Analyzer (gas list; explicit H2S exclusion). gasmet.com. — Cited by: Helium, noble gases & co-tracers.

Gasometrix

• miniRUEDI Portable Mass Spectrometer. (product page). gasometrix.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).

Geolog

• Representative Formation Gas extraction and accurate quantification. (product/technical literature). geolog.com. — Cited by: Mud-gas logging for H2 while drilling.

Geotech / QED

• BIOGAS 5000. product pages (optional H₂ 0–1,000 ppm cell). norrscope.com; diamondsci.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Geotech / QED Environmental Systems

• GA5000 Portable Gas Analyzer. product specification page. qedenv.com; Van Walt / ERE Inc. distributor specification pages. vanwalt.com; ereinc.com. — Cited by: Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration.

Gigaphoton

• 193nm High Power Laser for Drilling with High Aspect Ratio into Wide Bandgap Materials. (GT40A, 45 W). gigaphoton.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Global O-Ring and Seal

• Viton® O-Rings: Extreme Durability. (rapid gas decompression context). globaloring.com. — Cited by: Downhole & borehole H2 sensing.

Gold Hydrogen

• Significant Concentrations of Hydrogen and Helium Detected in the Ramsay 1 Well. (ASX release, October 31, 2023). goldhydrogen.com.au. — Cited by: Mud-gas logging for H2 while drilling, Helium, noble gases & co-tracers.

Gold Hydrogen Ltd

• Ramsay Project. page. goldhydrogen.com.au. — Cited by: Geologic context: the measurement problem in H2 exploration, Helium, noble gases & co-tracers.

Gold Hydrogen Ltd / CSIRO

• Soil Gas Survey Information Sheet — Yorke Peninsula Soil Gas Survey. goldhydrogen.com.au. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Google Patents. US5498960A

• NMR logging of natural gas in reservoirs. patents.google.com. — Cited by: Downhole & borehole H2 sensing.

Grapheal company/product information

• Grapheal raises €1.9m to develop graphene-based biosensors. Silicon Republic, siliconrepublic.com; “New product for seamless graphene biosensing,” Graphenea, graphenea.com. — Cited by: 2D-material & nanostructure FET sensors.

H2scan

• Frequently Asked Questions for H2scan Hydrogen Sensors and Products. h2scan.com. — Cited by: Palladium resistive & nanomaterial sensors.
• H2scan Introduces Intrinsically Safe Gen 5 Hydrogen Sensor Family for Hazardous Location Applications. (press release). h2scan.com. — Cited by: Palladium resistive & nanomaterial sensors.
• H2scan is proud to introduce the HY-OPTIMA 2710, a new hydrogen analyzer specifically designed to provide high accuracy measurements at low hydrogen concentrations. h2scan.com. — Cited by: Geologic context: the measurement problem in H2 exploration.
• HY-OPTIMA 700B Series Process Hydrogen Analyzer. h2scan.com. — Cited by: Why hydrogen is hard to sense.
• HY-OPTIMA In-Line Hydrogen Process Monitor. (product-family overview). h2scan.com. — Cited by: Palladium resistive & nanomaterial sensors.
• HY-OPTIMA Series In-Line Hydrogen Process Monitor. product/FAQ pages (Sieverts partial-pressure device, 1 ATM calibration, pressure-compensation guidance, per-model CO/H2S tolerance). h2scan.com; h2scan.com. — Cited by: Palladium resistive & nanomaterial sensors, Environmental covariance & signal interpretation.
• Hydrogen Detection Systems for Safer Processing. h2scan.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Solid-State Area Hydrogen Monitor HY-ALERTA 5021. (product page). h2scan.com. — Cited by: Why hydrogen is hard to sense, Palladium resistive & nanomaterial sensors.
• Tech Talk: The Future of Nuclear Safety — Innovative Hydrogen Sensors That Work Where Others Fail. h2scan.com. — Cited by: Palladium resistive & nanomaterial sensors.
• The Principles of Hydrogen Detection in Hydrogen Sensors. / “The Critical Importance of Hydrogen-Based Monitoring Across Utility and Industrial Applications.” h2scan.com (does not support the “Lundström-type” work-function terminology attributed to it above). — Cited by: Palladium resistive & nanomaterial sensors, Solid-electrolyte & high-temperature electrochemical sensors.
• h2scan.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.

H2Tools.org

• Hydrogen Diffusion in Air. (H2 Tools FAQ). h2tools.org. — Cited by: Why hydrogen is hard to sense.
• IEC 60079-29-1 Explosive atmospheres. (search-snippet summary; full page returned 403 on direct fetch); general t90/drift-requirement summary corroborated via search results for IEC 60079-29-1 Ed. 2.1. h2tools.org. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification.
• ISO 26142 Hydrogen Detection Apparatus – Stationary applications. (search-snippet summary; full page returned 403 on direct fetch). h2tools.org. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification, Reading a sensor datasheet.
• IEC 60079-29-2 Explosive atmospheres – Part 29-2: Gas detectors – Selection, installation, use and maintenance of detectors for flammable gases and oxygen. h2tools.org. — Cited by: Standards, regulations & certification.

Halliburton

• Surface data logging / GasFACTS advanced gas analysis service materials. halliburton.com. — Cited by: Mud-gas logging for H2 while drilling.

Hamamatsu Photonics

• Deuterium Lamps (D2 Lamps). technical datasheet TLS1017E. hamamatsu.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Deuterium Lamps for Photoionization. L7293/L13301 datasheet TLS1019E. hamamatsu.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Flame sensor (UV TRON) R2868. product/datasheet page. hamamatsu.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Photomultiplier Tube R821. datasheet TPMH1210E (Cs-Te photocathode, ~160–320 nm spectral response). hamamatsu.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Topic: Hydrogen flame detection. UVTRON application note. hamamatsu.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Hart Energy

• Downhole electronics: How hot can you go?. hartenergy.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

HazlocDirectory

• Temperature class (T-class) vs Auto-ignition Temperature (AIT). hazlocdirectory.com; SST Sensing, “Hazardous Area Gas Groups and Temperature Classifications” sstsensing.com. — Cited by: Standards, regulations & certification.

HCPCF Technology

• Glophotonics. glophotonics.fr; Photonic Microcell & Hollow Core Photonic Crystal Fiber. glophotonics.fr. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

Hermann Sewerin GmbH

• VARIOTEC 460 Tracergas. product page and technical documentation. sewerin.com. — Cited by: Geologic context: the measurement problem in H2 exploration.

HexlonEx

• What Is ATEX vs. IECEx? Key Differences, Zones, and When Each Applies. hexlonex.com. — Cited by: Standards, regulations & certification.

Hiden Analytical

• QGA 2.0 — Next Generation Gas Analyser. hidenanalytical.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• HPR-40 DSA: Membrane Inlet Mass Spectrometers for Dissolved Species Analysis. Brochure TDS 171/3. hideninc.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Dissolved H2 in groundwater & formation water.
• Mass Spectrometers for Residual Gas Analysis Applications (RGA), catalogue TDS-188-9. hidenanalytical.com. — Cited by: Helium, noble gases & co-tracers.

High-Sensitivity

• High-Resolution Stimulated Raman Photoacoustic Spectroscopy Enabled by Continuous-Wave Intracavity Pump-Stokes Beams, Nie et al, Laser & Photonics Reviews, 2024/2025. onlinelibrary.wiley.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

Honeywell

• 4 Series Gas Sensors. (CiTiceL 4HYT hydrogen sensor). automation.honeywell.com; datasheet PDF (fetch unsuccessful in this session): prod-edam.honeywell.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• CAT 25 CiTipeL® Combustible Gas Sensor — Product Data Sheet. Doc. Ref. cat25.indd, ECN I 4643, Issue 4, 14 Nov 2016. prod-edam.honeywell.com. — Cited by: Catalytic pellistors, How the sensor families actually differ: a transduction decoder, Figures of merit: how to compare any two H2 sensors honestly.
• Correction Factors for Combustible Gas (LEL) Sensors, technical note. automation.honeywell.com. — Cited by: Reading a sensor datasheet.

Horiba

• Hydrogen Flame Ionization Detection Method (FID). horiba.com. — Cited by: Mud-gas logging for H2 while drilling.
• Thermal Conductivity Detector Method (TCD) for Measuring Hydrogen. horiba.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Calibration, drift & QA/QC for H2 field programs.

HyTerra Ltd

• Projects. (Nemaha Project, Kansas; Geneva Project, Nebraska — well composition results; this landing page confirms Nemaha “up to 96% H2, 5% He” and Geneva “44% H2, 13% He,” but does not itself display the more granular Sue Duroche-3 96.1% H2 or McCoy 1 83% H2 figures cited alongside this reference in the Vendors table — those are independently verifiable via HyTerra’s ASX announcements). hyterra.com. — Cited by: Mud-gas logging for H2 while drilling, Geologic context: the measurement problem in H2 exploration, Helium, noble gases & co-tracers.

Ibsen Photonics

• The effect of cooling CCD detectors for spectroscopy. ibsen.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

IDAES documentation

• Wassiljewa-Mason-Saxena Method for Low-pressure Gas Mixture Thermal Conductivity. idaes-pse.readthedocs.io. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC), Environmental covariance & signal interpretation.

IEC

• IEC 60079-29-1 Ed. 2.1 b:2020 — Explosive atmospheres – Part 29-1: Gas detectors – Performance requirements of detectors for flammable gases. webstore.iec.ch. webstore.iec.ch (link corrected — publication/642 resolves to the withdrawn first edition, 2007); summary: nenvitech.com. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification, Figures of merit: how to compare any two H2 sensors honestly.
• IEC 60079-29-4 Ed.1.0 b:2009 — Explosive atmospheres — Part 29-4: Gas detectors — Performance requirements of open path detectors for flammable gases. webstore.ansi.org. — Cited by: Standards, regulations & certification.
• Ingress Protection (IP) ratings. iec.ch; Industrial Scientific, “Gas Detector IP Ratings: Why do they Matter?” indsci.com. — Cited by: Standards, regulations & certification.

IECEx

• Certified equipment scheme. iecex.com. — Cited by: Standards, regulations & certification.

Illinois EPA

• Soil Gas Sampling Protocol. epa.illinois.gov. — Cited by: Gas chromatography (lab, micro, and field GC).

Industrial Monitor Direct

• Hydrogen Gas LEL Limits and Exposure Safety for Industrial Facilities. (comparative ignition-energy/burning-velocity figures). industrialmonitordirect.com. — Cited by: Why hydrogen is hard to sense, Downhole & borehole H2 sensing, Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.

Industrial Safety Services

• Dräger XXS Electrochemical Sensor — Hydrogen H2. product page. isssafety.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Industrial Scientific

• Electrochemical Gas Sensor Cross Interference Table. indsci.com. — Cited by: Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation.
• LEL Sensors Compared: Catalytic Bead, IR, and MPS™. indsci.com. — Cited by: Catalytic pellistors.
• Ventis® MX4. product page (CO/H2-low electrochemical sensor option). indsci.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• What You Need to Know about Sensor Poisons and Inhibitors. indsci.com. — Cited by: Geologic context: the measurement problem in H2 exploration.
• MX6 iBrid 6-Gas Monitor (0–2,000 ppm electrochemical H2 channel, 1 ppm resolution). indsci.com. — Cited by: Dissolved H2 in groundwater & formation water.

INFICON

• Datasheet Micro GC Fusion® — Hydrogen in Natural Gas. inficon.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Micro GC Fusion Gas Analyzer. product page and “Monitoring H2 in Pipeline-Quality Natural Gas with Micro GC Fusion” application note. inficon.com; inficon.com. — Cited by: Gas chromatography (lab, micro, and field GC), Downhole & borehole H2 sensing, Soil-gas surveys: hardware, protocols & survey design.
• Monitoring H2 in Pipeline-Quality Natural Gas with Micro GC Fusion. inficon.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Protec P3000(XL) Helium Leak Detector. inficon.com. — Cited by: Helium, noble gases & co-tracers.
• UL3000 Fab Series — Helium Leak Detectors. inficon.com (the fetched page does not state the “2 ppm sniffer sensitivity” or “5×10⁻⁶ mbar·L/s at 90% RH” figures — real product, unconfirmed specifics). — Cited by: Helium, noble gases & co-tracers.

Infineon Technologies

• XENSIV™ TCI H2 sensor: Hydrogen sensor based on thermal conductivity principle. infineon.com. — Cited by: Why hydrogen is hard to sense.

Insplorion AB

• About us: We are NanoPlasmonic Sensing. insplorion.com. — Cited by: Plasmonic & metamaterial sensors.
• Hydrogen detection: improved safety & reliable applications. (NPS-P2 product page). insplorion.com. — Cited by: Plasmonic & metamaterial sensors.
• Insplorion officially launches the Insplorion NPS-P2 hydrogen detector. insplorion.com. — Cited by: Plasmonic & metamaterial sensors.
• Instrument: Insplorion M8 8-Channel Analyser. insplorion.com. — Cited by: Plasmonic & metamaterial sensors.
• Quarterly report Q2 2025. insplorion.com. — Cited by: Plasmonic & metamaterial sensors.
• Insplorion has completed its strategic review and entered into an agreement in principle regarding the sale of its hydrogen sensor business to Mann Teknik AB for SEK 5.5 million. (Feb 2026). insplorion.com. — Cited by: Plasmonic & metamaterial sensors.

International Gas Detectors

• BS EN 60079-29-1 – Explosive Atmospheres. internationalgasdetectors.com. — Cited by: Standards, regulations & certification.

IntrinsicallySafeStore

• Class 1 Division 1 Explained: Safety in Hazardous Locations. intrinsicallysafestore.com (supports general Class I Div 1 discussion but not the specific Group B seal-interval/listed-fittings claim). — Cited by: Standards, regulations & certification.

IOPscience

• Discrimination of Binary Gas Mixture Using CMUT Based Sound Attenuation Spectrum Gas Sensor. iopscience.iop.org (title-level). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Rovibrationally Resolved Direct Photodissociation Through the Lyman and Werner Transitions of H2 for FUV/X-ray-Irradiated Environments. ApJ 746, 78. iopscience.iop.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Measurement of minimum ignition energy in hydrogen-air mixtures. Journal of Physics: Conference Series 301, 012039. iopscience.iop.org (actual title Kumamoto et al., “…hydrogen-oxygen-nitrogen premixed gas by spark discharge”; supports H2 MIE ≈0.017 mJ but not the cited methane/propane comparison). — Cited by: Standards, regulations & certification.

ISA

• ISA12.13, Performance Requirements for Combustible Gas Detectors (committee page); ANSI/ISA-12.13.01-2013 record. isa.org. — Cited by: Standards, regulations & certification.

ISO

• ISO 26142:2010 — Hydrogen detection apparatus — Stationary applications. iso.org. iso.org. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification, Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.
• ISO 6142-1:2015 — Gas analysis — Preparation of calibration gas mixtures — Part 1: Gravimetric method for Class I mixtures. and “ISO 6142-2:2024 — Part 2: Gravimetric method for Class II mixtures.” iso.org; iso.org. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification.
• ISO 19229:2019 — Gas analysis — Purity analysis and the treatment of purity data. iso.org. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• ISO 6143:2001 / ISO 6143:2025 — Gas analysis — Comparison methods for determining and checking the composition of calibration gas mixtures. iso.org. — Cited by: Standards, regulations & certification.
• ISO 19880-1:2020 — Gaseous hydrogen — Fuelling stations — Part 1: General requirements. iso.org. — Cited by: Standards, regulations & certification.

Isotech Laboratories

• Gas Analyses — compositional + stable-isotope gas analysis service (Basic GC, Full GC, offline/online GC-IRMS; He/H2 25 ppm–100%). isotechlabs.com. — Cited by: Helium, noble gases & co-tracers, Isotopic & genetic fingerprinting.
• Natural-gas analytical service page. isotechlabs.com. — Cited by: Helium, noble gases & co-tracers.
• Water Analyses — DG-1/DG-2/DG-3 dissolved-gas packages (hydrogen not listed among standard dissolved-gas analytes). isotechlabs.com. — Cited by: Dissolved H2 in groundwater & formation water.

IUPAC

• limit of detection (L03540). IUPAC Compendium of Chemical Terminology (Gold Book). goldbook.iupac.org. — Cited by: Reading a sensor datasheet, How the sensor families actually differ: a transduction decoder, Figures of merit: how to compare any two H2 sensors honestly.
• faradaic current (F02321). IUPAC Compendium of Chemical Terminology (Gold Book). goldbook.iupac.org. — Cited by: How the sensor families actually differ: a transduction decoder.
• electrochemical method of detection (E01944). IUPAC Compendium of Chemical Terminology (Gold Book). goldbook.iupac.org. — Cited by: How the sensor families actually differ: a transduction decoder.
• amount concentration (A00295). IUPAC Compendium of Chemical Terminology (Gold Book). goldbook.iupac.org. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• potentiometric selectivity coefficient (P04791). IUPAC Compendium of Chemical Terminology (Gold Book). goldbook.iupac.org. — Cited by: Figures of merit: how to compare any two H2 sensors honestly.

JMS Consultants

• Catalytic Gas Sensor Poisoning: A Silent Threat to Safety. resources.jmsconsultants.co.uk. — Cited by: Catalytic pellistors, Reading a sensor datasheet.
• The Requirement of Oxygen for Catalytic Sensors. resources.jmsconsultants.co.uk. — Cited by: Catalytic pellistors.

KIN-TEK Analytical

• Trace Source™ Disposable/Refillable Permeation Tubes. kin-tek.com; kin-tek.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.

KMLabs

• High Harmonic Generation | HHG | XUUS. product/technology page. kmlabs.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Koloma. Company

• Koloma raises $50M more in quest to find natural hydrogen underground. Canary Media. canarymedia.com. — Cited by: Downhole & borehole H2 sensing.

La Française de l’Énergie

• FDE Announces the Discovery of Natural Hydrogen in the Lorraine Mining Basin. (15% H2 at 1,093 m; ~98% estimated at ~3,000 m; downhole measurement program led by P. de Donato and J. Pironon, GeoRessources/CNRS/Université de Lorraine). francaisedelenergie.fr. — Cited by: Downhole & borehole H2 sensing, Geologic context: the measurement problem in H2 exploration.

Lab-Club

• L1835 high-intensity VUV deuterium lamp, water-cooled, 115-400 nm. lab-club.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

LabX

• Buy SRI Instruments 8610C, New & Used Prices. labx.com. — Cited by: Gas chromatography (lab, micro, and field GC).

Larson Electronics

• Understanding Class, Divisions, Groups and Zones in NEC and the CEC Hazardous Locations. larsonelectronics.com. — Cited by: Standards, regulations & certification.

LCGC/Chromatography Online

• The Flame Ionization Detector. chromatographyonline.com. — Cited by: Gas chromatography (lab, micro, and field GC).

LCSC Electronics

• VQ548ZD. product/price listing. lcsc.com. — Cited by: Catalytic pellistors.

LegalClarity

• Class I Hazardous Locations: Divisions, Zones & Equipment. legalclarity.org. — Cited by: Standards, regulations & certification.

Leutert

• Geothermal Fluid Sampler. leutert.com. — Cited by: Downhole & borehole H2 sensing.
• Positive Displacement Sampler PDSshort. leutert.com. — Cited by: Downhole & borehole H2 sensing.

Leybold

• PHOENIX Portable Helium leak detectors. leybold.com. — Cited by: Helium, noble gases & co-tracers.
• Helium leak detection, and how spray and sniffer techniques are used for local leak tests. leybold.com; leybold.com. — Cited by: Helium, noble gases & co-tracers.

LI-COR Biosciences

• LI-7810 CH4/CO2/H2O Trace Gas Analyzer Specifications. Doc 982-17412 (03/2023). ekotechnika.cz. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Linde

• Linde Specialty Gas Mixtures. lindedirect.com; “Quality control and quality assurance in specialty gases,” Linde. linde-gas.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.

Los Gatos Research / ABB

• Ultraportable Greenhouse Gas Analyzer (CH4, CO2, H2O) Datasheet. lgrinc.ru. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Lotus Instruments

• Operating Parameters for the Thermal Conductivity Detector. lotusinstruments.com (title-level via search). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Lyell Collection

• Generation, migration and accumulation of natural hydrogen and helium in the intracratonic São Francisco Basin, eastern Brazil. Geoenergy (2024). lyellcollection.org. — Cited by: Helium, noble gases & co-tracers.
• The principles of helium exploration. Petroleum Geoscience (2021). lyellcollection.org. — Cited by: Isotopic & genetic fingerprinting.

Malvern Panalytical

• Handheld LIBS analyzers. product category page. malvernpanalytical.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Marco Rubber & Plastics

• O-Ring Permeation Chart. marcorubber.com. — Cited by: Downhole & borehole H2 sensing.

McPherson

• VUV and Deep Ultraviolet Spectrometer. Model 234/302. mcphersoninc.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• MgF2 Window Deuterium. light source, Model 632/634 datasheet (115 nm–visible, 30 W, 2000 h lifetime, no flowing gas/coolant/pump required). mcphersoninc.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

MDPI

• Development of a Table-Top High-Power, High-Stability, High-Harmonic-Generation Extreme-Ultraviolet Laser Source. Photonics 12, 942. mdpi.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Migration of Natural Hydrogen from Deep-Seated Sources in the São Francisco Basin, Brazil. Geosciences 10(9), 346 (2020). mdpi.com. — Cited by: Helium, noble gases & co-tracers.
• An Accurate Model for Estimating H2 Solubility in Pure Water and Aqueous NaCl Solutions. Energies 15(14), 5021 (2022). mdpi.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Comparison of Transfer Learning and Established Calibration Transfer Methods for Metal Oxide Semiconductor Gas Sensors. Atmosphere 14(7), 1123 (2023). mdpi.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Utilization of a Low-Cost Sensor Array for Mobile Methane Monitoring. Sensors 24(2), 519 (2024). mdpi.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• A Gas Leakage Detection Device Based on the Technology of TinyML. Technologies (MDPI) 11(2), 45 (2023). mdpi.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Precision and Limits of Detection for Selected Commercially Available, Low-Cost Carbon Dioxide and Methane Gas Sensors. Sensors 19(14), 3157 (2019). mdpi.com; pmc.ncbi.nlm.nih.gov. — Cited by: Reading a sensor datasheet.
• Overcoming the Slow Recovery of MOX Gas Sensors through a System Modeling Approach. Sensors 12(10), 13664 (2012). mdpi.com. — Cited by: Reading a sensor datasheet.
• Improved Hydrogen-Sensing of TiO2 Schottky Device Through Schottky Barrier Height Modulation. Sensors 26(4), 1400 (2026). mdpi.com (does not support the claims as cited — Pt electrodes not Au, barrier modulated via annealing not bias). — Cited by: How the sensor families actually differ: a transduction decoder.

MeasureMonitorControl

• Understanding ATEX Codes. measuremonitorcontrol.com. — Cited by: Standards, regulations & certification.

Membrapor AG

• Hydrogen Gas Sensor H2/C-40000. datasheet. membrapor.ch (link corrected — original URL 404s; verified specs: 0–40,000 ppm range, 80,000 ppm overload, 4 ± 3 nA/ppm, T90 < 45 s). — Cited by: Electrochemical cells (amperometric & potentiometric).
• Hydrogen Gas Sensor H2/CA-1000. datasheet. membrapor.ch. — Cited by: Electrochemical cells (amperometric & potentiometric), How the sensor families actually differ: a transduction decoder.
• Hydrogen Gas Sensor H2/CB-1000. datasheet. membrapor.ch. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Hydrogen Gas Sensor H2/M-1000. datasheet (zero shift specification, 18 ppm over +20…+40 °C, per search-indexed content). membrapor.ch. — Cited by: Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation, Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.

MetricGate

• Limit of Detection (LOD) and LOQ. metricgate.com. — Cited by: Figures of merit: how to compare any two H2 sensors honestly.

Metrohm

• 2060 Raman Analyzer. product page. metrohm.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Midstream Calculator

• Gas Chromatograph Calibration — GPA 2261, ISO 6974. (general GC calibration/carryover practice context). midstreamcalculator.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.

MinEx CRC

• Pre-commercial product brochure: Laser-induced Breakdown Spectroscopy (LIBS). downhole logging tool. minexcrc.com.au. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

mirSense

• Compact OEM gas analyser modules based on quantum cascade laser technology. Envirotech Online. envirotech-online.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Industry & Environment. mirsense.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

Molecular Hydrogen Institute

• Concentration and Solubility of H2 (saturation ≈1.6 mg/L at 1 atm/25 °C; conventional-water background ≈8.65×10⁻⁷ mg/L). molecularhydrogeninstitute.org. — Cited by: Dissolved H2 in groundwater & formation water, Gas-phase vs. aqueous-phase H2 sensing.

Mordor Intelligence

• Gas Detectors Market – Companies & Report. (market-size/price commentary; does not support the specific US$500–3,000 fixed-point-system figure attributed to it — that report cites $500–1,500 for portable units and >US$1M for refinery-scale fixed installs). mordorintelligence.com. — Cited by: Catalytic pellistors.

MSA Safety

• Carbon Monoxide Sensor Cross-Sensitivities: Alcohols, VOCs & Hydrogen. technical bulletin. s7d9.scene7.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Hydrogen Flame Detector — FL500-H2 (UV/IR Flame Detector for Hydrogen Applications). product and specifications pages. us.msasafety.com; specifications: docs.msasafety.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Rethinking Gas Leak Detection with Ultrasonic Technology. (operational pressure threshold context, ≥2 bar/29 psi for reliable ultrasonic leak generation). blog.msasafety.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• SAW MiniCAD mk II Miniature Chemical Agent Detector. product datasheet. media.msanet.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Ultrasonic Leak Detector Observer-I — Acoustic Gas Detection. product page. us.msasafety.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Nano Environmental Technology S.r.l

• Katharometer gas technology. nenvitech.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

NASA

• Enhanced Aluminum reflecting and solar-blind filter coatings for the [FUV]. ntrs.nasa.gov. — Cited by: Why hydrogen is hard to sense.
• Technology Readiness Levels Demystified. nasa.gov. — Cited by: Plasmonic & metamaterial sensors, Reading a sensor datasheet.

NASA ADS

• Hydrogen generation during serpentinisation in ophiolite complexes: A comparison of H2-rich gases from Oman, Philippines and Turkey. EGU General Assembly abstract (2013). ui.adsabs.harvard.edu. — Cited by: Isotopic & genetic fingerprinting.

NatH2investing

• HyTerra’s McCoy 1 well intersects hydrogen up to 83% and helium up to 5% in Kansas. nath2investing.com. — Cited by: Helium, noble gases & co-tracers.

National Energy Technology Laboratory

• Raman Gas Analyzer. R&D Fact Sheet R-D106 (June 2022) and “Raman Gas Analyzer for Natural Gas and Syngas Applications.” netl.doe.gov (link dead); netl.doe.gov. — Cited by: Why hydrogen is hard to sense, Raman spectroscopy (spontaneous, gas phase).

National K Works

• Vacuum Flask | Downhole Tools. nationalkworks.com. — Cited by: Downhole & borehole H2 sensing.

National Renewable Energy Laboratory

• High-Temperature Electronics and Packaging. NREL Geothermal Research. nrel.gov. — Cited by: Downhole & borehole H2 sensing.

Nature

• Natural hydrogen resource accumulation in the continental crust. Nature Reviews Earth & Environment (2025). nature.com. — Cited by: Helium, noble gases & co-tracers.
• A global dataset of helium isotopic data in tectonically and hydrothermally active geological environments. Scientific Data (2025). nature.com. — Cited by: Helium, noble gases & co-tracers.

Nature Scientific Reports

• Gas discrimination by simultaneous sound velocity and attenuation measurements using uncoated capacitive micromachined ultrasonic transducers. nature.com (title/topic confirmed via search synthesis; full text behind login redirect in this session). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Neroxis

• MTCS 2601 — Gas — Micro Thermal Conductivity Sensor. brochure, neroxis.ch (specs via search synthesis: Pirani range 10⁻⁴–1000 mbar, <6 mW). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

NETL

• Harsh Environment Electronics Packaging for Downhole Oil & Gas Exploration. netl.doe.gov. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

Nevada Nanotech

• Catalytic Bead Gas Sensor Limitations. nevadanano.com. — Cited by: Catalytic pellistors, Calibration, drift & QA/QC for H2 field programs.
• MPS Flammable Gas Sensor. nevadanano.com and nevadanano.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• NDIR Sensor: Are There Disadvantages to Consider?. nevadanano.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• nevadanano.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.

New Jersey Department of Health

• Right-to-Know Hazardous Substance Fact Sheet: Hydrogen (simple asphyxiant; no substance-specific OSHA PEL or ACGIH TLV). nj.gov. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.

Newark/element14

• Amphenol SGX Sensortech MiCS-5914 product/pricing listing. newark.com. — Cited by: Metal-oxide (MOX) chemiresistors.

Newcastle Safety Servicing

• Gas Monitor t90 Response Time. newcastlesafetyservicing.com. — Cited by: Reading a sensor datasheet.

NFPA

• NFPA 2, Hydrogen Technologies Code (2026 edition). nfpa.org. — Cited by: Standards, regulations & certification.

Nissha FIS

• Inc. Hydrogen sensor (catalytic-combustion, FH2-HY series) product page. connect.nissha.com. — Cited by: Metal-oxide (MOX) chemiresistors.

Nissha FIS, Inc

• FIS Gas Sensor SB-19-00 for Hydrogen Detection. specifications (SP1900E). fisinc.co.jp. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation.
• FIS Gas Sensor SP-19-01 for Hydrogen Detection. specifications (SP1901E_P). fisinc.co.jp. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation.

NIST

• BEB Electron-Impact Ionization Cross Section Graph for Hydrogen Molecule (H2). Electron-Impact Cross Sections for Ionization and Excitation Database. physics.nist.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Dielectric Permittivity of Eight Gases Measured with Cross Capacitors. Int. J. Thermophys. nist.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• NIST Traceable Reference Material Program for Gas Standards. nist.gov; NIST SP 260-126, “The NIST Traceable Reference Material Program for Gas Standards.” nvlpubs.nist.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• The 3-0 Quadrupole Band in H2 by Cavity Ring-Down Spectroscopy. nist.gov. — Cited by: Why hydrogen is hard to sense.
• Traceable Calibration Gases: SRMs, NTRMs, and Protocol Gases. nist.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification.
• NIST Chemistry WebBook, Hydrogen (C1333740): molecular weight (2.01588 g/mol) and Henry’s-law constant data (k°H ≈ 7.8×10⁻⁴ mol kg⁻¹ bar⁻¹). webbook.nist.gov; webbook.nist.gov. — Cited by: Dissolved H2 in groundwater & formation water, Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure, Gas-phase vs. aqueous-phase H2 sensing.
• NIST Chemistry WebBook, Water (C7732185): standard enthalpy of formation, gas phase, Δ_fH° = −241.83 kJ/mol. webbook.nist.gov. — Cited by: How the sensor families actually differ: a transduction decoder.
• CODATA recommended values of the fundamental physical constants (2019 SI redefinition): molar gas constant R = 8.314462618 J mol⁻¹ K⁻¹, Faraday constant F, elementary charge e, Avogadro constant N_A, Boltzmann constant k. physics.nist.gov; physics.nist.gov; physics.nist.gov; physics.nist.gov; physics.nist.gov. — Cited by: How the sensor families actually differ: a transduction decoder, Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure, Gas-phase vs. aqueous-phase H2 sensing.

NOAA

• CCL – Services. gml.noaa.gov/ccl/services.html. gml.noaa.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Scales for WMO GAW CCL. gml.noaa.gov/ccl/scales.html. gml.noaa.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Adoption of the WMO Scale for H2 Measurements. gml.noaa.gov (original gmd-int.cmdl.noaa.gov link dead — TLS certificate no longer matches; corrected to current gml.noaa.gov host). — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Atmospheric H2 observations from the NOAA Cooperative Global Air Sampling Network. Atmospheric Measurement Techniques 17, 4803–4824. amt.copernicus.org (see also OSTI record: osti.gov and MPI repository copy: pure.mpg.de). — Cited by: Gas chromatography (lab, micro, and field GC), Calibration, drift & QA/QC for H2 field programs, Soil-gas surveys: hardware, protocols & survey design, Standards, regulations & certification, Reading a sensor datasheet, Figures of merit: how to compare any two H2 sensors honestly.

NPL (National Physical Laboratory)

• Hydrogen primary reference gas mixtures. npl.co.uk. — Cited by: Standards, regulations & certification.

NSF PAR

• A review of genetic identification of natural gas. NSF Public Access Repository. par.nsf.gov. — Cited by: Helium, noble gases & co-tracers.

NSW Resources Regulator

• Safety alert: Response times of gas detectors (SA17-10). resources.nsw.gov.au. — Cited by: Reading a sensor datasheet.

Ocean Drilling Program (Texas A&M)

• C. Borehole Fluid Sampling with WSTP and Kuster Tools. Technical Note 10. www-odp.tamu.edu. — Cited by: Downhole & borehole H2 sensing.

Ogawa

• Absorption coefficients of O2 at the Lyman-alpha line and its vicinity. JGR 73, 21, 6759. agupubs.onlinelibrary.wiley.com; search-result synthesis on the O2 transmission-window minimum near 1216 Å and mesospheric Lyman-alpha penetration to 70–75 km via cross sections ≤10⁻²¹–10⁻²⁰ cm². — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Oil & Gas

• Tornado Spectral Systems (link dead — Tornado was acquired by Bruker in Jan 2024 and this URL now redirects to a generic Bruker Raman-process page that does not mention Tornado, oil & gas/LNG, or homonuclear-diatomic detection; no live replacement page with equivalent content was located). tornado-spectral.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

OSTI

• Dewarless Logging Tool – 1st Generation. (Technical Report, Sandia National Laboratories). osti.gov; osti.gov. — Cited by: Downhole & borehole H2 sensing.

PatSnap Eureka

• Limit of Detection (LOD) Calculations: 3σ Method vs IUPAC Guidelines. eureka.patsnap.com. — Cited by: Reading a sensor datasheet.

Peak Laboratories

• Peak Performer 1 RCP (Reducing Compound Photometer). product specifications. puregasproducts.com; see also peaklaboratories.com and gasanalysisservices.com. — Cited by: Gas chromatography (lab, micro, and field GC), Dissolved H2 in groundwater & formation water.

Pfeiffer Vacuum / Instrument Specialists

• OmniStar / ThermoStar — The New Gas Analysis Systems. instrument-specialists.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• ASM 306S helium/hydrogen sniffer leak detector — sniffer-mode sensitivity floor set by ~5 ppm atmospheric He, and startup/response-time specifications (via reseller product listings). ajvs.com; subzeroscientific.com (quoted “~5 ppm in air” claim not located verbatim on the cited pages). — Cited by: Helium, noble gases & co-tracers.
• PRISMA pro (QMA 250) quadrupole mass spectrometer — minimum detection limit (search-synthesized). pfeiffer-vacuum.com. — Cited by: Helium, noble gases & co-tracers.

Picarro

• G2201-i Analyzer Datasheet. picarro.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• G2401 CO2, CO, CH4 and H2O Gas Concentration Analyzer Datasheet. picarro.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• GasScouter G4302 CH4, C2H6 and H2O Analyzer Datasheet. picarro.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.

PMC (PubMed Central)

• Mantle-Derived Helium Distribution and Tectonic Implications in the Sichuan–Yunnan Block, China. PMC8600645. pmc.ncbi.nlm.nih.gov. — Cited by: Helium, noble gases & co-tracers.
• H2-rich fluids from serpentinization: Geochemical and biotic implications. PMC516479. pmc.ncbi.nlm.nih.gov. — Cited by: Helium, noble gases & co-tracers.
• The H2/CH4 ratio during serpentinization cannot reliably identify biological signatures. PMC5036043. ncbi.nlm.nih.gov. — Cited by: Helium, noble gases & co-tracers, Isotopic & genetic fingerprinting.
• Rapid High-Sensitivity Analysis of Methane Clumped Isotopes (Δ13CH3D and Δ12CH2D2) Using Mid-Infrared Laser Spectroscopy. PMC11755397 (2025). ncbi.nlm.nih.gov. — Cited by: Isotopic & genetic fingerprinting.
• Correction to “Rapid High-Sensitivity Analysis of Methane Clumped Isotopes (Δ13CH3D and Δ12CH2D2) Using Mid-Infrared Laser Spectroscopy.” PMC12120809 (2025). ncbi.nlm.nih.gov. — Cited by: Isotopic & genetic fingerprinting.
• Recent Advances and Prospects in Design of Hydrogen Permeation Barrier Materials for Energy Applications—A Review. PMC9570512 (2022). pmc.ncbi.nlm.nih.gov. — Cited by: Isotopic & genetic fingerprinting.
• Recent Advances and Challenges of Nanomaterials-Based Hydrogen Sensors. PMC8626019. pmc.ncbi.nlm.nih.gov. — Cited by: Standards, regulations & certification.
• Transport Properties of NaCl in Aqueous Solution and Hydrogen Solubility in Brine. Journal of Physical Chemistry B (2023), PMC10591480. pmc.ncbi.nlm.nih.gov. — Cited by: Dissolved H2 in groundwater & formation water.
• Towards standardized microbial hydrogen consumption testing in the subsurface: harmonized field sampling and enrichment approaches. World Journal of Microbiology and Biotechnology (2025), PMC12464130. pmc.ncbi.nlm.nih.gov. — Cited by: Dissolved H2 in groundwater & formation water.
• Highly sensitive hydrogen sensor based on graphite-InP or graphite-GaN Schottky barrier with electrophoretically deposited Pd nanoparticles. PMC3212005. ncbi.nlm.nih.gov (current-change ratio ≈7×10⁵ at 0.1% H2, not “more than a millionfold”). — Cited by: How the sensor families actually differ: a transduction decoder.

PNAS

• Abiotic methane formation during experimental serpentinization of olivine. Proceedings of the National Academy of Sciences (2016). pnas.org; pmc.ncbi.nlm.nih.gov. — Cited by: Helium, noble gases & co-tracers.

Posifa Technologies

• Hydrogen Sensor for fuel cell and safety applications — PGS1000. (thermal-conductivity type; cited as contrast to Pd-resistive). posifatech.com. — Cited by: Why hydrogen is hard to sense, Palladium resistive & nanomaterial sensors.
• PGS1000 Hydrogen Sensor. posifatech.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• PGS4100 datasheet specifications via search synthesis (resolution 10 ppm analog/2 ppm digital, range 0–4 vol%, accuracy 1200 ppm 0–20,000 ppm and 6% above, temperature drift 1000 ppm, long-term stability 1200 ppm/5 yr, response 1 s, warm-up 1 s, op. temp −40 to 85 °C), posifatech.com (link updated 2026-07-04; original 2023/03 path returned 404) and posifatech.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

PowerLink

• Glophotonics product page. glophotonics.fr. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

Praxair

• Hydrogen Compressed Gas. Safety Data Sheet (LEL 4%, UEL 75%). dept.harpercollege.edu. — Cited by: Why hydrogen is hard to sense.

Precise Downhole Solutions

• Technologies. (PureLight™ Fiber Optic Pressure Gauge; sapphire/quartz gauges). precisedhs.com. — Cited by: Downhole & borehole H2 sensing.

Proserv

• Downhole Sampling. proserv.com; Proserv Downhole Sampling Equipment Catalog. s3.us-west-1.wasabisys.com. — Cited by: Downhole & borehole H2 sensing.

Pumpport

• ATEX Directive 2014/34/EU – Equipment Categories and Ex Protection Types. pumpport.com. — Cited by: Standards, regulations & certification.

QED Environmental Systems Ltd

• GA5000 Technical Specifications. datasheet, DS45-Issue.15. wiserenvironment.co.uk. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

QIMC

• RETRANSMISSION: QIMC Reports Multi-Component Hydrocarbon and Helium Soil-Gas Anomalies in the New-Salem Area, Cumberland Basin Project, Nova Scotia. newsfilecorp.com. — Cited by: Helium, noble gases & co-tracers.

Raman Hydrogen Sensor

• Phase 1, Spectral Sciences Inc, DTIC ADA273783 (historical SBIR/AEDC program; 0.0013 atm LOD, 0.3 s response, 18 mW). apps.dtic.mil. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

Renesas Electronics

• ZMOD4410 Gas Sensor Module for TVOC and Indoor Air Quality. datasheet and product page. renesas.com. — Cited by: Metal-oxide (MOX) chemiresistors, Sensor arrays, e-noses & machine-learning selectivity.
• ZMOD4510 Gas Sensor Module for Nitrogen Dioxide and Ozone. datasheet. renesas.com. — Cited by: Metal-oxide (MOX) chemiresistors, Sensor arrays, e-noses & machine-learning selectivity.

ResearchGate

• Radon: A Tracer for Geochemical Exploration. researchgate.net. — Cited by: Helium, noble gases & co-tracers.
• Which Carrier gas (Ar or He) will be suitable in GC TCD detector to determine hydrogen evolution from a photocatalytic reactor? (discussion thread). researchgate.net. — Cited by: Helium, noble gases & co-tracers.
• Correction of H3+ Contributions in Hydrogen Isotope Ratio Monitoring Mass Spectrometry. researchgate.net. — Cited by: Isotopic & genetic fingerprinting.

ResearchGate figure

• Measured reflectance of an Al+MgF2 mirror from 310 Å to 1600 Å. researchgate.net. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Restek

• Molecular Sieve 5A and 13X Packed GC Columns for Permanent Gas Separations. discover.restek.com (supports the general 5A-vs-13X retention/CO-detection distinction; does not support the specific pore-size figures, the PLOT-format-dominance claim, or the H2/He/Ne void-resolution claim cited to it above). — Cited by: Gas chromatography (lab, micro, and field GC).

SAE International

• J2578_202301: Recommended Practice for General Fuel Cell Vehicle Safety. saemobilus.sae.org. — Cited by: Standards, regulations & certification.
• J2579_202301: Standard for Fuel Systems in Fuel Cell and Other Hydrogen Vehicles. saemobilus.sae.org. — Cited by: Standards, regulations & certification.

SAFCell

• Inc. company/technology background (Haile group, Caltech; founded by Calum Chisholm, 2009; ~250 °C solid-acid fuel cells and hydrogen generation/purification licensing from Caltech/Northwestern). safcell.com (link dead as of 2026-07; company/technology background corroborated via NASA Spinoff: spinoff.nasa.gov). — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

Sandfort

• Goldschmidt, Wöllenstein & Palzer, Cavity-Enhanced Raman Spectroscopy for Food Chain Management, Sensors 18(3):709, 2018, PMC5876629 (Fraunhofer IPM PDH/high-finesse CERS approach; not the Hippler group). ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).

Sandia National Laboratories

• Sandia sensor follows unusual tech transfer path. news release, October 16, 2007. newsreleases.sandia.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

SciAps

• Making a case for handheld LIBS in mineral exploration. (company blog/application article). sciaps.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Z-Series LIBS Analyzers. product page (Z-903: 190–950 nm range, detects H–U; PULSAR laser 5–6 mJ/pulse, up to 50 Hz, 1 ns pulses; ~4 lb with battery). sciaps.com; Malvern Panalytical, “SciAps Z-903 Handheld LIBS Analyzer.” malvernpanalytical.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging, UV/EUV electronic transitions & fluorescence — the physics veto.

ScienceDirect

• Photodissociation dynamics of water at Lyman alpha (121.6 nm). sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Nitrogen isotopes of released gas from rock crushing and implications to origins of molecular nitrogen in Lower Cambrian overmature shale gas in South China. sciencedirect.com. — Cited by: Helium, noble gases & co-tracers.
• Nitrogen speciation in mantle and crustal fluids (2014). sciencedirect.com. — Cited by: Helium, noble gases & co-tracers.
• Application of radon (²²²Rn) as an environmental tracer in hydrogeological and geological investigations: An overview. sciencedirect.com. — Cited by: Helium, noble gases & co-tracers.
• Radon as a tracer for helium exploration in geothermal areas. sciencedirect.com. — Cited by: Helium, noble gases & co-tracers.
• Extreme methane deuterium, nitrogen and helium enrichment in natural gas from the Homorod seep (Romania) (2010). sciencedirect.com. — Cited by: Helium, noble gases & co-tracers.
• Soil geochemistry of hydrogen and other gases along the San Andreas fault. International Journal of Hydrogen Energy (2023). sciencedirect.com; EarthArxiv preprint eartharxiv.org. — Cited by: Helium, noble gases & co-tracers.
• Comment on “Molecular hydrogen in surface and subsurface natural gases: Abundance, origins and ideas for deliberate exploration” by Alexei V. Milkov. Earth-Science Reviews (2023). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Kinetics of D/H isotope fractionation between molecular hydrogen and water. Geochimica et Cosmochimica Acta (2018). sciencedirect.com; osti.gov. — Cited by: Isotopic & genetic fingerprinting.
• Experimental determination of hydrogen isotopic equilibrium in the system H2O(l)-H2(g) from 3 to 90 °C. Geochimica et Cosmochimica Acta (2025). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Natural hydrogen (white hydrogen) exploration methods and identification of sources: A comprehensive overview (2026). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Application of an absolute reference frame for methane clumped-isotope analyses. Chemical Geology 646, 121922 (2024). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Multiple origins of methane at the Lost City Hydrothermal Field. Earth and Planetary Science Letters (2010). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Reduced gas seepages in ophiolitic complexes: Evidences for multiple origins of the H2-CH4-N2 gas mixtures. Geochimica et Cosmochimica Acta (2017). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Mantle helium in Sacramento basin natural gas wells. Geochimica et Cosmochimica Acta (1986). sciencedirect.com. — Cited by: Isotopic & genetic fingerprinting.
• Solubility of hydrogen in sodium chloride brine at high pressures. Fluid Phase Equilibria (2021). sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Solubility of H2 in water and NaCl brine under subsurface storage conditions: Measurements and thermodynamic modeling. International Journal of Hydrogen Energy (2023–2024). sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Effects of temperature and pressure on Henry’s law constant for hydrogen in the primary water of a simulated pressurized-water reactor. Progress in Nuclear Energy (2017). sciencedirect.com. — Cited by: Dissolved H2 in groundwater & formation water.
• Comparison of analytical methods and calibration methods for correction of detector response drift in arrays of carbon black-polymer composite vapor detectors. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• OdorNet: A lightweight odor recognition method for TinyML in handheld electronic noses using spatiotemporal pseudo-images. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.
• Field and laboratory performance evaluations of 28 gas-phase air quality sensors by the AQ-SPEC program. Atmospheric Environment (2019). sciencedirect.com. — Cited by: Reading a sensor datasheet.
• Quantitative Study of the Resolving Power of Arrays of Carbon Black−Polymer Composites in Various Vapor-Sensing Tasks. Analytical Chemistry. pubs.acs.org. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

ScienceDirect Topics

• Flame Ionization Detector. sciencedirect.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Schumann-Runge Band. overview (175–204 nm structured band system). sciencedirect.com. — Cited by: Why hydrogen is hard to sense, UV/EUV electronic transitions & fluorescence — the physics veto.

Scion Instruments

• The Different Types of GC Detectors. scioninstruments.com. — Cited by: Helium, noble gases & co-tracers.
• Refinery Gas Analysis using the SCION Rapid RGA Analyzer (ASTM D1945 component sensitivity 0.01 mol% general, 0.3 mol% for H2S). scioninstruments.com. — Cited by: Helium, noble gases & co-tracers.

SemeaTech Inc

• 4-Series H2-1000 Sensor. datasheet. eoc-inc.com. — Cited by: Electrochemical cells (amperometric & potentiometric).

Sensirion

• Datasheet STC31 - CO2 Sensor Based on Thermal Conductivity Measurement Principle. and STC31-C design guide (RH/O2 low-cross-sensitivity mode). sensirion.com; sensirion.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Environmental covariance & signal interpretation.
• Hydrogen for Fuel Cells sensors. sensirion.com. — Cited by: Palladium resistive & nanomaterial sensors.
• What is a metal oxide (MOX) sensor?. Information note. sensirion.com. — Cited by: Metal-oxide (MOX) chemiresistors, Calibration, drift & QA/QC for H2 field programs, Sensor arrays, e-noses & machine-learning selectivity.
• SGP41 gas sensor product page and open-source Gas Index Algorithm. sensirion.com; github.com. — Cited by: Sensor arrays, e-noses & machine-learning selectivity.

SensorsONE

• Compensated Temperature Range. sensorsone.com. — Cited by: Reading a sensor datasheet.

Servomex

• Zirconia Gas Analyzer Technology. servomex.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

SGX Sensortech

• TC-1326 MEMS - Thermal Conductivity Sensor Elements. sgxsensortech.com. — Cited by: Why hydrogen is hard to sense.
• VQ series thermal conductivity sensor family, sgx.cdistore.com and related VQ-series distributor listings (title-level via search synthesis). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• MiCS-2714. datasheet. sgxsensortech.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• MiCS-5524. datasheet, 1084 rev 8. sgxsensortech.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• MiCS-5914. datasheet, 1108 rev 4. sgxsensortech.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• MP-7217 Datasheet. DS-0165 Issue 5, 03-May-2016. sgxsensortech.com. — Cited by: Catalytic pellistors, Figures of merit: how to compare any two H2 sensors honestly.
• VQ500 Series Datasheet. DS-0223 Issue 2, 10-May-2016. sgxsensortech.com. — Cited by: Catalytic pellistors.
• TC-1326-A/TC-1326-AS MEMS Thermal Conductivity Sensor Elements. sgxsensortech.com (title-level; PDF text not machine-readable in this session). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Pulsed Power Operation of the MPEL MEMS Pellistor. Application Note MiCS-MP-7217, 2047 rev 0. sgxsensortech.com. — Cited by: Catalytic pellistors.

SLB

• DQ1000 Wellsite Mass Spectrometer Gas Analyzer. slb.com; “dq1000 – Mass Spectrometer Wellsite Gas Analyzer.” Continental Laboratories. continentallabs.com. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing.
• FlairFlex Advanced Real-Time Fluid Logging and Analysis Service. (product page). slb.com. — Cited by: Mud-gas logging for H2 while drilling.
• InSitu Fluid Analyzer System. slb.com. — Cited by: Downhole & borehole H2 sensing.
• MDT Forte and MDT Forte-HT Testers. slb.com. — Cited by: Downhole & borehole H2 sensing.
• The Defining Series: Mud Logging. (Oilfield Review). slb.com. — Cited by: Mud-gas logging for H2 while drilling.

SLB Energy Glossary

• hydrogen index. glossary.slb.com. — Cited by: Downhole & borehole H2 sensing.
• neutron porosity. glossary.slb.com. — Cited by: Downhole & borehole H2 sensing.

SLB Oilfield Glossary

• hydrogen index. glossary.oilfield.slb.com. — Cited by: Downhole & borehole H2 sensing.

SOT (Singapore Optics Technology)

• Lithium Fluoride (LiF) Optical Crystal | UV to IR Windows. (transparency 105 nm–6 µm). sot.com.sg. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

South Australian Department for Energy and Mining

• Natural hydrogen (CSIRO noble-gas laboratory groundwater helium purity results, 20–25%, trace ³He). energymining.sa.gov.au (unverified — page blocked fetch access; the specific 20–25% figure could not be independently located). — Cited by: Helium, noble gases & co-tracers.

SPE Energy Stream

• Drilling Challenges in Exploration for Subsurface Natural Geologic Hydrogen. (webinar). streaming.spe.org. — Cited by: Mud-gas logging for H2 while drilling.

SPIE

• ArF excimer laser for 193-nm lithography. spiedigitallibrary.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

Springer

• Vacuum-ultraviolet photodetectors. PhotoniX — general VUV instrumentation context. link.springer.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

SRI Instruments

• Model 8610C Gas Chromatograph. product page. srigc.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Natural Gas Analyzer GC. and “310 Soil Gas GC System” product pages (these two pages do not themselves list hydrogen as a target analyte or confirm TCD detection of H2 for these specific models — does not support the H2-detection claim made for them in this page’s tables). srigc.com; srigc.com; and “Surprising concentrations of hydrogen and non-geological methane and carbon dioxide in the soil,” Fuel/ScienceDirect. sciencedirect.com. — Cited by: Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• Operating the SRI RGD (Reduction Gas Detector). operation manual. srigc.com. — Cited by: Gas chromatography (lab, micro, and field GC), Dissolved H2 in groundwater & formation water.
• RGD – Reduction Gas Detector. sri-instruments-europe.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• 2023 Price List. srigc.com. — Cited by: Gas chromatography (lab, micro, and field GC).

SST Sensing

• Zirconia Oxygen Sensor System. product page. sstsensing.com. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.

Stanford Research Systems

• Gas Correction Factors for Bayard-Alpert Ionization Gauges. Application Note. thinksrs.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• QCM100 – Quartz Crystal Microbalance Theory and Calibration. application note. thinksrs.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers), Figures of merit: how to compare any two H2 sensors honestly.
• QCM200 product page. thinksrs.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Models RGA100, RGA200, and RGA300 Residual Gas Analyzer: Operating Manual and Programming Reference. Rev. 1.8. thinksrs.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Figures of merit: how to compare any two H2 sensors honestly.

StockTitan

• Primary Hydrogen (HNATF) finds 665 ppm and 531 ppm H2 in NL soil gas survey. stocktitan.net. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Gas chromatography (lab, micro, and field GC).

Storyplace.org.au

• A Necessary Invention. (history of the Zeiss ZGL 2505 interferometer at Teralba Colliery, NSW). storyplace.org.au. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Stratum Reservoir

• The ALL NEW IsoTube: The Industry Standard for Gas Sampling. stratumreservoir.com. — Cited by: Isotopic & genetic fingerprinting.

Studylib

• IEC 60079-29-1: Gas Detectors for Flammable Gases Performance Requirements. studylib.net. — Cited by: Reading a sensor datasheet.

Swagelok

• Know Your Process Analyzers: Raman Analyzers. swagelok.com. — Cited by: Raman spectroscopy (spontaneous, gas phase).

Taylor & Francis

• TCD – Knowledge and References. taylorandfrancis.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Teledyne FLIR

• FLIR GF343 Optical Gas Imaging Camera. (discontinued) and “Avoid an outage with new hydrogen leak detection technology” application note (CO₂ tracer-gas method for H₂ leak visualization). flir.com; flir.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.

Thermo Fisher Scientific

• EA-IRMS: Fast and Precise Isotope Analysis of Liquids. documents.thermofisher.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• GA5000 Portable Gas Analyser. datasheet (±0.5% FS CH4/CO2, ±1% O2 accuracy claim). documents.thermofisher.com. — Cited by: Electrochemical cells (amperometric & potentiometric), Calibration, drift & QA/QC for H2 field programs.
• Gas Isotope Ratio Mass Spectrometry (IRMS). thermofisher.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Niton Apollo Handheld LIBS Analyzer. product page. thermofisher.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• 253 Plus IRMS brochure (gas-source magnetic-sector IRMS; hydrogen continuous-flow capability). documents.thermofisher.com. — Cited by: Isotopic & genetic fingerprinting.
• MAT 253: The Gold Standard for Isotope Ratio MS, brochure. documents.thermofisher.com. — Cited by: Isotopic & genetic fingerprinting.
• 253 Ultra High Resolution Isotope Ratio MS brochure (clumped-isotope work). assets.thermofisher.com. — Cited by: Isotopic & genetic fingerprinting.

ToolGrit

• Gas Detector Cross-Sensitivity Guide. toolgrit.com. — Cited by: Reading a sensor datasheet.

Transense Technologies plc

• SAW Technology. product/technology page. transense.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

TSI Inc

• Photo-Ionization Detection (PID) Technology. Application Note TSI-147 (10.6 eV krypton lamp principle; major/minor air components have IP >12.0 eV so don’t interfere with VOC PID measurement). tsi.com; Wikipedia, “Photoionization detector.” en.wikipedia.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

UC Davis Stable Isotope Facility

• Homepage and sunset notice (continuous-flow IRMS services, H/C/N/O/S; announced sunset effective July 2026). stableisotopefacility.ucdavis.edu. — Cited by: Isotopic & genetic fingerprinting.

UL Standards & Engagement

• UL 2075 — Gas and Vapor Detectors and Sensors. (scope summary via search results). shopulstandards.com; H2tools summary: h2tools.org. — Cited by: Calibration, drift & QA/QC for H2 field programs, Standards, regulations & certification.

Unisense A/S

• H2 microsensor (Clark-type amperometric): product specifications, measurement principles, and “New and improved H2 microsensor” (0.3 µM LOD; 0–2,000 µM; t90 <15 s). unisense.com; unisense.com; unisense.com. — Cited by: Dissolved H2 in groundwater & formation water.

University of Toronto

• Sherwood Lollar, B., faculty profile, Department of Earth Sciences. es.utoronto.ca. — Cited by: Isotopic & genetic fingerprinting.

UNT Digital Library / OSTI

• Elimination of Heat-Shielding for Geothermal Tools Operating Up To 300 Degrees Celsius. digital.library.unt.edu; osti.gov. — Cited by: Downhole & borehole H2 sensing.

US EPA

• EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards. epa.gov; vendor copy: airgas.com (link corrected — original URL without the CDN token now returns 400). — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Distinguishing the source of natural gas accumulations with a combined gas geochemistry approach. epa.gov. — Cited by: Helium, noble gases & co-tracers.
• RSKSOP-175, Sample Preparation and Calculations for Dissolved Gas Analysis in Water Samples (GC headspace-equilibration technique). archive.epa.gov. — Cited by: Dissolved H2 in groundwater & formation water.

US Patent 11,680,476

• High temperature and high pressure AlGaN/GaN electronics. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 4,411,867

• Reduction gas detector. image-ppubs.uspto.gov. — Cited by: Gas chromatography (lab, micro, and field GC).

US Patent 6,853,798

• Downhole geothermal well sensors comprising a hydrogen-resistant optical fiber. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 6,939,717

• Hydrogen sulphide detection method and apparatus. Schlumberger Technology Corporation. freepatentsonline.com. — Cited by: Downhole & borehole H2 sensing.

US Patent 7,173,239

• Method and apparatus for downhole quantification of methane using near infrared spectroscopy. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 7,219,541

• Method and apparatus for downhole fluid analysis for reservoir fluid characterization. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 7,268,662

• Passive SAW-based hydrogen sensor and system. image-ppubs.uspto.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

US Patent 7,274,082 B2

• Chemical sensor using chemically induced electron-hole production at a Schottky barrier. patents.google.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.

US Patent 8,276,459

• High temperature transducer using SOI electronics. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 8,518,702

• Downhole spectroscopic hydrogen sulfide detection. Schlumberger Technology Corporation. freepatentsonline.com. — Cited by: Downhole & borehole H2 sensing.

US Patent 8,536,524

• Fast mud gas logging using tandem mass spectroscopy. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 8,646,968

• Method for performing optical distributed temperature sensing (DTS) measurements in hydrogen environments. image-ppubs.uspto.gov. — Cited by: Downhole & borehole H2 sensing.

US Patent 9,383,340

• Passive, wireless, surface acoustic wave identification tag with hydrogen gas sensor. image-ppubs.uspto.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).

USGS

• 3H/3He Dating Background. water.usgs.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Isotopic & genetic fingerprinting.
• Helium isotopes carry messages from the mantle. USGS Yellowstone Volcano Observatory. usgs.gov. — Cited by: Helium, noble gases & co-tracers.
• National assessment of helium resources within known natural gas reservoirs. Scientific Investigations Report 2021-5085. pubs.usgs.gov. — Cited by: Helium, noble gases & co-tracers.
• 3H/3He Noble Gas Sampling. USGS Groundwater Dating Laboratory. water.usgs.gov. — Cited by: Isotopic & genetic fingerprinting.
• Analytical Services and Prices. Reston Stable Isotope Laboratory. usgs.gov. — Cited by: Isotopic & genetic fingerprinting.
• Geologic Hydrogen. USGS Central Energy Resources Science Center. usgs.gov. — Cited by: Standards, regulations & certification.

USPTO patent document

• Molecular fluorine laser. (F2 laser 157 nm technical background). image-ppubs.uspto.gov. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.

VICI (Valco Instruments)

• VICI pulsed discharge detectors. product literature. vici.com. — Cited by: Gas chromatography (lab, micro, and field GC).

WatchGas

• Combustible Gas Sensors. technical note. watchgas.com; Blackline Safety, “Pellistor (Catalytic Bead) Sensor Technical Notes.” support.blacklinesafety.com (link dead — redirects to generic Blackline Safety help-center homepage; no working replacement located). — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Application Note 4 — Sensor Technical Data Summaries. Carbon Monoxide (CO) – Low Hydrogen Interference table (T-dependent false readings, 18/36/54 ppm at 10/20/30 °C for 900 ppm H2). Corrected during 2026-07 citation verification — the MSA Safety bulletin previously cited here does not contain this data. watchgas.com. — Cited by: Environmental covariance & signal interpretation.

West Systems s.r.l

• The West Systems Portable Fluxmeter — Diffuse Flux. portablefluxmeter.com. — Cited by: Soil-gas surveys: hardware, protocols & survey design.

Wikipedia

• Balmer series. en.wikipedia.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Catalytic bead sensor. en.wikipedia.org. — Cited by: Catalytic pellistors.
• Cavity ring-down spectroscopy. en.wikipedia.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Formation evaluation neutron porosity. en.wikipedia.org. — Cited by: Downhole & borehole H2 sensing.
• Hydrogen sensor. Wikipedia, The Free Encyclopedia. en.wikipedia.org. — Cited by: Palladium resistive & nanomaterial sensors.
• List of refractive indices. (n(H₂) = 1.000132, n(air) = 1.000293, both at 0 °C/1 atm, 589.29 nm). en.wikipedia.org. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• List of thermal conductivities. en.wikipedia.org. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Helium, noble gases & co-tracers.
• Lyman-alpha. (121.567 nm, 10.2 eV, strong atmospheric absorption, requires vacuum spectroscopy or satellite observation). en.wikipedia.org. — Cited by: Why hydrogen is hard to sense, UV/EUV electronic transitions & fluorescence — the physics veto.
• Lyman–Werner photons. en.wikipedia.org. — Cited by: Why hydrogen is hard to sense.
• Mud logging. en.wikipedia.org (does not support the capital-cost claim). — Cited by: Mud-gas logging for H2 while drilling.
• Palladium hydride. Wikipedia, The Free Encyclopedia. en.wikipedia.org. — Cited by: Palladium resistive & nanomaterial sensors, How the sensor families actually differ: a transduction decoder.
• Pulsed discharge ionization detector. en.wikipedia.org. — Cited by: Gas chromatography (lab, micro, and field GC), Helium, noble gases & co-tracers.
• Resonance-enhanced multiphoton ionization. en.wikipedia.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Speed of sound. en.wikipedia.org. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Thermal conductivity detector. applications section, en.wikipedia.org (see also [8]). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC).
• Van Deemter equation. en.wikipedia.org. — Cited by: Gas chromatography (lab, micro, and field GC).
• Hydrogen-cooled turbo generator. en.wikipedia.org and handwiki.org (λ_H2 ≈ 0.168 W/(m·K) cited in this source, slightly different from the 0.187 brief value, reflecting normal cross-source spread — accessed via search synthesis 2026-07-04). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Radon-222. en.wikipedia.org (half-life 3.82146 days; alpha decay to ²¹⁸Po; member of the U-238 decay series); corroborating ScienceDirect Topics “Radon 222” and RadiaCode isotope reference radiacode.com. — Cited by: Helium, noble gases & co-tracers.
• Helium production in the United States (0.3% He economic cutoff; helium-lean/helium-rich reservoir terminology). en.wikipedia.org. — Cited by: Helium, noble gases & co-tracers.
• Hydrogen isotope biogeochemistry (citing Hoefs, J., 2009, Stable Isotope Geochemistry). en.wikipedia.org. — Cited by: Isotopic & genetic fingerprinting.
• Density of air — molar mass of dry air ≈ 0.0289652 kg/mol, citing the CIPM/Picard et al. moist-air density formulation. en.wikipedia.org. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• Mole fraction — IUPAC “amount fraction” terminology; ideal-gas volume-fraction/mole-fraction equivalence via Avogadro’s law. en.wikipedia.org. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• Henry’s law — dimensionless/volatility/solubility Henry’s-constant forms; Bunsen and Ostwald coefficient definitions. en.wikipedia.org. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• Air pollutant concentrations — ppmv vs. mg/Nm³ reporting conventions in emissions regulation. en.wikipedia.org. — Cited by: Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• Technology readiness level. en.wikipedia.org. — Cited by: Reading a sensor datasheet.

Winsen

• Catalytic Bead Hydrogen Sensors: Principles, Features, and Applications. winsen-sensor.com; Blackline Safety, “Pellistor (Catalytic Bead) Sensor Technical Notes.” support.blacklinesafety.com (link dead — redirects to generic help.blacklinesafety.com homepage). — Cited by: Why hydrogen is hard to sense, Catalytic pellistors, Geologic context: the measurement problem in H2 exploration.
• Catalytic Sensors: Principles, Applications, and Performance. winsen-sensor.com. — Cited by: Catalytic pellistors.
• Electrochemical Hydrogen Sensor Module ZE07-H2. Product page. winsen-sensor.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Electrochemical Hydrogen Sensors: Principles, Applications, and Advantages. winsen-sensor.com. — Cited by: Why hydrogen is hard to sense, Geologic context: the measurement problem in H2 exploration.
• Flammable Gas Sensor (Model: MQ-8). manual v1.3. cdn.sparkfun.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• H2 sensor. product-line overview (ME3-H2 / ZE03-H2 / ZE07-H2). winsen-sensor.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• MC105 Catalytic Flammable Gas Sensor User’s Manual. winsen-sensor.com. — Cited by: Catalytic pellistors.
• ME3-H2 Electrochemical Hydrogen Gas Sensor. Product page / manual. winsen-sensor.com. — Cited by: Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation.
• ME3-H2S datasheet specification summary (zero-current drift <±0.5 µA/month) via alldatasheet.com listing. alldatasheet.com (link corrected — original URL pointed to the ME3-H2 sensor datasheet, a different product from the ME3-H2S this citation describes); product page: winsen-sensor.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• ME4-H2 Hydrogen Gas Sensor. Product page. winsen-sensor.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• MQ-8 Hydrogen Sensor. product page. winsen-sensor.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• ZE03 Electrochemical H2 Gas Sensor Module. product page. winsen-sensor.com. — Cited by: Metal-oxide (MOX) chemiresistors.
• Pellistor Application Note 6 — Pellistor Poisoning. sgxsensortech.com. — Cited by: Why hydrogen is hard to sense, Reading a sensor datasheet.

Xensor Integration

• Thermal Conductivity Gauge XEN-TCG3880. datasheet, isweek.com (title/summary via search synthesis; PDF text not machine-readable in this session). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• XEN-5310/XEN-5320 datasheets, xensor.nl xensor.nl and xensor.nl (specs via search synthesis of these documents, including 9 ms/36 ms time constants, 1–3% FS accuracy, −40 to +85 °C, ~1200 ppm/yr drift, 5–8 V/~20 mA). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.

Yamazoe, N

• Receptor Function and Response of Semiconductor Gas Sensor. Journal of Sensors 2009, Article 875704. 10.1155/2009/875704 onlinelibrary.wiley.com. — Cited by: Metal-oxide (MOX) chemiresistors, How the sensor families actually differ: a transduction decoder.

Zgonnik, V

• The occurrence and geoscience of natural hydrogen: A comprehensive review. Earth-Science Reviews 203, 103140. sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Geologic context: the measurement problem in H2 exploration.

Uncredited & general web resources

• 3D Fractals as SERS Active Platforms: Preparation and Evaluation for Gas Phase Detection of G-Nerve Agents. PMC6187359. ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• A Catalytic-Plasmonic Pt Nanoparticle Sensor for Hydrogen Detection in High-Humidity Environments. ACS Sensors. 10.1021/acssensors.5c03166 pmc.ncbi.nlm.nih.gov. — Cited by: Plasmonic & metamaterial sensors.
• A combined ultrasonic flow meter and binary vapour mixture analyzer for the ATLAS silicon tracker. arxiv.org (title-level; PDF text not extractable in this session). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• A compact hydrogen sensor based on the fiber-optic Fabry-Perot interferometer. Optics and Lasers in Engineering. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• A High-Precision Hydrogen Sensor Array Based on Pt-Modified SnO2 for Suppressing Humidity and Oxygen Interference. Chemosensors 13(8), 294 (MDPI). 10.3390/chemosensors13080294. — Cited by: Why hydrogen is hard to sense.
• A Highly Sensitive Hydrogen Sensor with Gas Selectivity Using a PMMA Membrane-Coated Pd Nanoparticle/Single-Layer Graphene Hybrid. ACS Applied Materials & Interfaces. 10.1021/am5073645 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• A MEMS Pirani Vacuum Gauge Based on Porous Silicon. MDPI Micromachines / PMC11946229, pmc.ncbi.nlm.nih.gov (title/topic-level via search synthesis). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• A New Gas Analysis Method Based on Single-Beam Excitation Stimulated Raman Scattering in Hollow Core Photonic Crystal Fiber Enhanced Raman Spectroscopy (does not support the Dicke-narrowing/gain-coefficient claim it is cited for in Mechanism & physics). pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• A Quadrupole Mass Spectrometer for Resolution of Low Mass Isotopes. University of Liverpool Mass Spectrometry (preprint/reprint PDF); abstract at ScienceDirect. liverpool.ac.uk; sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• A Review of Distributed Fiber–Optic Sensing in the Oil and Gas Industry. IEEE Journals & Magazine. ieeexplore.ieee.org. — Cited by: Downhole & borehole H2 sensing.
• A review of piezoelectric MEMS sensors and actuators for gas detection application. PMC9971541, ncbi.nlm.nih.gov (title-level, CMUT/FBAR context). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• A Review of Quartz Crystal Microbalance for Chemical and Biological Sensing Applications. Sensing and Imaging. pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• A Robust Miniaturized Gas Sensor for H2 and CO2 Detection Based on the 3ω Method. PMC8780541, pmc.ncbi.nlm.nih.gov; also MDPI Sensors 22(2):485, mdpi.com (Note: does not support the 60 °C/two-orders-of-magnitude temperature-interference figure cited alongside it in the Environmental covariance & cross-sensitivity section.). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Environmental covariance & signal interpretation.
• A route to detect H2 in ambient conditions using a sensor based on reduced graphene oxide. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors.
• A safe and high-precision detection method for hydrogen leakage analysis of underground gas storage based on stimulated Raman spectroscopy of micro-nanofiber. Fuel. sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• A Short Review of Cavity-Enhanced Raman Spectroscopy for Gas Analysis, Sensors 21(5):1698, 2021. mdpi.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• A study on MIS Schottky diode based hydrogen sensor using La2O3 as gate insulator. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• A Versatile Capacitive Sensing Platform for the Assessment of the Composition in Gas Mixtures. Micromachines 11(2), 116; PMC7074232. pmc.ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• A World First for Xcalibur Smart Mapping: 3D Hydrogen Plume Mapping with Quantum Raman Spectrometer. xcaliburmp.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• About Us. Intelligent Optical Systems, Inc. intopsys.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Absolute absorption cross-section measurements of Schumann–Runge continuum of O2 at 90 and 295 K. J. Mol. Spectrosc.; ADS record 2005JMoSp.229.238Y. ui.adsabs.harvard.edu; ScienceDirect abstract: sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Absolute Raman Scattering Cross-Section of Molecular Hydrogen. ui.adsabs.harvard.edu; researchgate.net. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Absolute rotational Raman cross sections for N2, O2, and CO2 (JOSA, 1974) and Raman cross section of some simple gases (JOSA, 1973) — values for N2 absolute backscatter cross-section (1.64×10⁻²⁹ cm²/sr) and H2 relative cross-section (2.2× N2 at 5145 Å). opg.optica.org; opg.optica.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Absorption cross section measurements of water vapor in the wavelength region 120 to 188 nm. Chem. Phys. 211, 387; ADS record. ui.adsabs.harvard.edu. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Activation process of reversible Pd thin film hydrogen sensors. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Advanced Mud Gas Logging Techniques for Hydrogen Exploration. SPE Middle East Oil and Gas Show and Conference, OnePetro, onepetro.org (title-level; abstract 403 in this session); “Key Role of Regearing Mud Gas Logging For Natural H2 Exploration,” SPWLA Annual Logging Symposium, onepetro.org (title-level). — Cited by: Raman spectroscopy (spontaneous, gas phase), Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC), Mass spectrometry (portable, membrane-inlet, isotopes), Mud-gas logging for H2 while drilling, Standards, regulations & certification.
• Advances in Chromatographic Analysis of Hydrocarbon Gases in Drilling Fluids — The Application of Semi-Permeable Membrane Technology to High Speed TCD Gas Chromatography. SPWLA Annual Logging Symposium (SPWLA-2005). onepetro.org. — Cited by: Mud-gas logging for H2 while drilling.
• Air Stable Nickel-Decorated Black Phosphorus and Its Room-Temperature Chemiresistive Gas Sensor Capabilities. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Airborne Gravity Gradiometry — Xcalibur Smart Mapping (FALCON AGG description). xcaliburmp.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• AlGaN/GaN Schottky diode hydrogen sensor performance at high temperatures with different catalytic metals. ScienceDirect. sciencedirect.com. — Cited by: Downhole & borehole H2 sensing.
• Alibaba distributor listing, XEN-TCG3880, price range referenced via search synthesis (US$10–20/unit, MOQ 2). alibaba.com. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• All-digital Sensor System for Distributed Downhole Pressure Monitoring in Unconventional Fields. OSTI Technical Report. osti.gov. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• All-fiber hydrogen sensor based on stimulated Raman gain spectroscopy with a 1550 nm hollow-core fiber (17 ppm LOD, 250 s). arxiv.org; IEEE conference version ieeexplore.ieee.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• All-Fiber Multicomponent Gas Raman Probe Based on Platinum-Coated Capillary Enhanced Raman Spectroscopy, ACS Sensors, 2025. pubs.acs.org; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• AMOF (Atmospheric Measurement and Observation Facility). WAO / Reduction Gas Analyser – H2 Monitor. amof.ac.uk. — Cited by: Gas chromatography (lab, micro, and field GC).
• An explanation of hysteresis of electrical resistance–composition relationship in the Pd–H(D) and Pd alloy–H(D) systems measured by a gas phase method. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Palladium resistive & nanomaterial sensors, Figures of merit: how to compare any two H2 sensors honestly.
• An optical fiber hydrogen concentration sensor based on Mach-Zehnder interferometer coated with a film of palladium. IEEE. ieeexplore.ieee.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• An Optical Fiber Hydrogen Sensor Using a Palladium-Coated Ball Lens. Journal of Lightwave Technology 33(12), 2535. opg.optica.org. — Cited by: Plasmonic & metamaterial sensors.
• An Ultra-Compact MEMS Pirani Sensor for In-Situ Pressure Distribution Monitoring. PMC9611872, pmc.ncbi.nlm.nih.gov (title-level). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Application of Advanced Mud Gas Logging for Improved Hydrocarbon Phase Determination in a Highly Depleted Reservoir. IPTC, OnePetro. onepetro.org. — Cited by: Downhole & borehole H2 sensing.
• AppliedSensor/ams HLS-440 family: Tracxn. tracxn.com (link dead); datasheet, datasheets.globalspec.com NREL FCEV crash-test report, docs.nrel.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Arrays of Regenerated Fiber Bragg Gratings in Non-Hydrogen-Loaded Photosensitive Fibers for High-Temperature Sensor Networks. PMC. ncbi.nlm.nih.gov. — Cited by: Downhole & borehole H2 sensing.
• Assessing the Portable Gas Analyzer GA5000 for Accurate H2 Monitoring in Geological Exploration. 2024/2025 preprint, HAL open archive. hal.science (summary via search snippet and ResearchGate listing: researchgate.net). — Cited by: Why hydrogen is hard to sense, Electrochemical cells (amperometric & potentiometric), Plasmonic & metamaterial sensors, Calibration, drift & QA/QC for H2 field programs, Environmental covariance & signal interpretation, Geologic context: the measurement problem in H2 exploration, Soil-gas surveys: hardware, protocols & survey design.
• ATEX-Certified, FPGA-Based Three-Channel Quantum Cascade Laser Sensor for Sulfur Species Detection in Petrochemical Process Streams. Sensors 25(3), 635. mdpi.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Atmospheric composition and climate impacts of a future hydrogen economy. (preprint). Atmospheric Chemistry and Physics (Copernicus), cited for the ~0.53 ppmv present-day tropospheric H2 background. acp.copernicus.org. — Cited by: Plasmonic & metamaterial sensors.
• Aura — characterising gases using Raman, IS-Instruments Ltd product page. is-instruments.com; Hollow core microstructured fibre optics for Raman analysis of gas. is-instruments.com; Patent awarded for gas phase Raman instrument. is-instruments.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Barometric-pumping controls fugitive gas emissions from a vadose zone natural gas release. PMC6773692. ncbi.nlm.nih.gov. — Cited by: Environmental covariance & signal interpretation.
• Best Practices and Operational Excellence of Well Integrity Surveillance in Oil and Gas Fields. SPE Middle East Oil and Gas Show and Conference, OnePetro. onepetro.org. — Cited by: Downhole & borehole H2 sensing.
• Calibration of MOX gas sensors in open sampling systems based on Gaussian Processes. (search-snippet summary). researchgate.net; “Drift in a popular metal oxide sensor dataset reveals limitations for gas classification benchmarks,” Sensors and Actuators B. sciencedirect.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Calorimetric Thermoelectric Gas Sensor for the Detection of Hydrogen, Methane and Mixed Gases. PMC4063010. ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Carbon Nanotube-Based Chemiresistive Sensors. Sensors 17(4), 882. pmc.ncbi.nlm.nih.gov; mdpi.com. — Cited by: 2D-material & nanostructure FET sensors.
• CARS Concentration Sensitivity With and Without Nonresonant Background Suppression, Eckbreth & Hall, Combustion Science and Technology 25(5-6), 1981. tandfonline.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Catalytic IR thermal imaging-based hydrogen detection. Sens. Actuators B. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Cavity ring-down spectroscopy of the electric quadrupole transitions of H2 in the 784–852 nm region. J. Mol. Spectrosc. sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Cavity-Enhanced Raman Spectroscopy for Detection of Trace Gaseous Impurities in Hydrogen for Fuel Cells, Analytical Chemistry, 2023 (0.5 ppm H2 LOD at 200 s, sub-ppm/ppb impurities at 0.1–2.5 MPa). pubs.acs.org; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Cavity-Enhanced Raman Spectroscopy in the Biosciences: In Situ, Multicomponent, and Isotope Selective Gas Measurements To Study Hydrogen Production and Consumption by Escherichia coli, Smith & Hippler, Analytical Chemistry, 2017 (also. PMC7006961 for related follow-on work). pubs.acs.org; pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Cavity-Enhanced Raman Spectroscopy of Natural Gas with Optical Feedback cw-Diode Lasers, Salter, Chu, Hippler, Analytical Chemistry 87(15), 2015. pubs.acs.org; open-access version: eprints.whiterose.ac.uk; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Change in the crystalline structure during the phase transition of the palladium–hydrogen system. Physical Chemistry Chemical Physics. pubs.rsc.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Chemically deposited palladium nanoparticles on graphene for hydrogen sensor applications. Scientific Reports. nature.com. — Cited by: 2D-material & nanostructure FET sensors.
• Cloudline and Xcalibur Smart Mapping to trial airship-based Raman LiDAR for airborne gas concentration mapping. xcaliburmp.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• CMOS Compatible Hydrogen Sensor Using Platinum Gate and ALD–Aluminum Oxide. Sensors 24(10), 3020, DOI 10.3390/s24103020. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Collision Enhanced Raman Scattering (CERS): An Ultra-High Efficient Raman Enhancement Technique for Hollow Core Photonic Crystal Fiber Based Raman Spectroscopy Gas Analyzer. pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Colloidally Engineered Pd and Pt Catalysts Distinguish Surface- and Vapor-Mediated Deactivation Mechanisms. ACS Catalysis (general Pt/Pd sintering mechanism background, not pellistor-specific). pubs.acs.org. — Cited by: Catalytic pellistors.
• Color Changing Hydrogen Sensors. NASA Technical Reports Server, 20150023595. ntrs.nasa.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Color Changing Material for Hydrogen Leak Detection. NASA Technical Reports Server, 20140012641. ntrs.nasa.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Comparative Experimental Study of a High-Temperature Raman-Based Distributed Optical Fiber Sensor with Different Special Fibers. PMC. pmc.ncbi.nlm.nih.gov; pv magazine Australia, “‘Active natural hydrogen field’ confirmed in SA’s Yorke Peninsula.” pv-magazine-australia.com. — Cited by: Geologic context: the measurement problem in H2 exploration.
• Computational Design of Alloy Nanostructures for Optical Sensing of Hydrogen. ACS Applied Nano Materials. 10.1021/acsanm.2c01189 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Considerations of Thermodynamics and Kinetics for the Effects of Relative Humidity on the Electrolyte in Electrochemical Toxic Gas Sensors. ACS Sensors. 10.1021/acssensors.1c01339. — Cited by: Electrochemical cells (amperometric & potentiometric), Environmental covariance & signal interpretation.
• Correction Model for Metal Oxide Sensor Drift Caused by Ambient Temperature and Humidity. PMC9101743. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation.
• Correlation between laser-induced breakdown spectroscopy signal and moisture content. Spectrochim. Acta B. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Cuttings-Lag Distribution in Directional Wells Affects Depth Resolution of Mud Logging. Journal of Petroleum Technology / SPE. jpt.spe.org. — Cited by: Mud-gas logging for H2 while drilling.
• Data-Driven Molecular Dynamics and TEM Analysis of Crystal Growth and Hydrogen Sensing in Pt-Functionalized Graphene Chemiresistive Sensors. arXiv:2504.05438. arxiv.org. — Cited by: 2D-material & nanostructure FET sensors.
• Deconvolution and compensation of mass spectrometric overlap interferences with the miniRUEDI portable mass spectrometer. PMC7490835. pmc.ncbi.nlm.nih.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Delegated Regressor, A Robust Approach for Automated Anomaly Detection in the Soil Radon Time Series Data. PMC7033208. ncbi.nlm.nih.gov. — Cited by: Environmental covariance & signal interpretation.
• Demystifying Raman analyzers: A comprehensive guide. Swagelok / PI Process Instrumentation. piprocessinstrumentation.com. — Cited by: Why hydrogen is hard to sense.
• Density-Neutron Log Porosity Guide. Infinita Lab. infinitalab.com. — Cited by: Downhole & borehole H2 sensing.
• Design and fabrication of MOSFET type hydrogen gas sensor using MEMS process. researchgate.net. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Design Principles for Sensitivity Optimization in Plasmonic Hydrogen Sensors. ACS Sensors. 10.1021/acssensors.9b02436 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• DetecTape® H2 Visual Hydrogen Leak Detector Tape. Element One / DetecTape product page. detectape.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Detection systems and methods using coherent anti-Stokes Raman spectroscopy (patent, background discussion of CARS nonresonant interference). image-ppubs.uspto.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Determination of permeation properties of hydrogen gas in sealing rubbers using thermal desorption analysis gas chromatography. Scientific Reports. nature.com. — Cited by: Gas chromatography (lab, micro, and field GC).
• Determining Absolute Neutrino Mass using Quantum Technologies. arXiv:2412.06338 (does not support the claim; this paper concerns cyclotron radiation emission spectroscopy and Rydberg-atom quantum magnetometry for neutrino-mass measurement and does not discuss REMPI). arxiv.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Developing Relative Humidity and Temperature Corrections for Low-Cost Sensors Using Machine Learning. 2021 (PMC). ncbi.nlm.nih.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Development of a subsurface LIBS sensor for in situ groundwater quality monitoring with applications in CO2 leak sensing in carbon sequestration. PMC6418306. pmc.ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Development of Long-Term Stable MXene-Based Gas Sensing Material. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Devkota et al. sputtered-InOx SAW H₂ sensor (12–124 MHz, 11.83 kHz/400 ppm, ~100 ppm LOD), cited via Acharya et al. review [33]; related. SAW-based gas sensors with rf sputtered InOx and PECVD SiNx films: Response to H2 and O3 gases. sciencedirect.com (does not support the 128°YX-LiNbO₃ substrate claim in the table above — the related paper uses 36°YX-LiTaO₃). — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Direct Comparison of PdAu Alloy Thin Films and Nanoparticles upon Hydrogen Exposure. ACS Applied Materials & Interfaces. 10.1021/acsami.8b22455 pmc.ncbi.nlm.nih.gov. — Cited by: Plasmonic & metamaterial sensors.
• Direct Measurement of Intrinsic Dirac Point and Fermi level at Graphene/Oxide interface and Its Band Alignment by Cavity Enhanced Internal Photoemission. NIST. nist.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Dislocations, texture and stress development in hydrogen-cycled Pd thin films: An in-situ X-ray diffraction study. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Distran / distributor product pages for Ultra Pro and Ultra Pro Max sensitivity and range specifications. keysfortomorrow.com; en.gazdetect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Downhole Electronic Components: Achieving Performance Reliability. JPT (SPE). jpt.spe.org. — Cited by: Why hydrogen is hard to sense.
• Drift-corrected nanoplasmonic hydrogen sensing by polarization. Nanoscale 7, 10963. 10.1039/C5NR01818H pubs.rsc.org. — Cited by: Plasmonic & metamaterial sensors.
• Early Detection of Hydrogen Leakage Using Fiber Optic Hydrogen Sensor Based on WO3-PdPt-Pt Nanocomposite Films. Sensors. pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• EERE Success Story - Element One Reduces Cost of Hydrogen Leak Detection Systems. U.S. Department of Energy. energy.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Effect of hydrogen gas on FBG-based optical fiber sensors for downhole pressure and temperature monitoring. ResearchGate / Academia.edu. researchgate.net; academia.edu. — Cited by: Downhole & borehole H2 sensing.
• Effect of Sintering Temperature on Adhesion Property and Electrochemical Activity of Pt/YSZ Electrode. Materials 2022, 15(10), 3471. pmc.ncbi.nlm.nih.gov. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Effects of poisoning gases on and restoration of PdCuSi metallic glass in a capacitive MEMS hydrogen sensor. sciencedirect.com. — Cited by: Why hydrogen is hard to sense.
• Effects of temperature and humidity on the performance of a PECH polymer coated SAW sensor. PMC9053706. pmc.ncbi.nlm.nih.gov. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Electric quadrupole transitions and collision-induced absorption in the region of the first overtone band of H2 near 1.25 μm. J. Mol. Spectrosc. sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Electrical percolation thresholds of semiconducting single-walled carbon nanotube networks in field-effect transistors. Physical Chemistry Chemical Physics, RSC. pubs.rsc.org. — Cited by: 2D-material & nanostructure FET sensors.
• Electrical resistivity of PdHx: I. Residual resistivity. Solid State Communications. sciencedirect.com. — Cited by: Palladium resistive & nanomaterial sensors, Figures of merit: how to compare any two H2 sensors honestly.
• Electrochemical quartz crystal microbalance studies of hydrogen absorption/desorption in Pd and Pd–Ag films. In situ monitoring of hydrogen absorption–desorption in Pd and Pd77Ag23 films by an electrochemical quartz crystal microbalance. sciencedirect.com; “Electrochemical quartz crystal microbalance study on hydrogen absorption and desorption into/from palladium and palladium–noble metal alloys,” sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Electrochemical Sensor for Hydrogen Leakage Detection at Room Temperature. pmc.ncbi.nlm.nih.gov (does not support the claim). — Cited by: Why hydrogen is hard to sense.
• Electrochemical Sensors. (biennial fundamental-reviews article covering potentiometric, voltammetric, and gas sensors), Analytical Chemistry; hosted at NIH PMC2883720. pmc.ncbi.nlm.nih.gov. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Engineering-oriented thermal conductivity discussion, ScienceDirect Topics. Thermal Conductivity of Gases — an overview. sciencedirect.com general Eucken-relation context. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Helium, noble gases & co-tracers.
• Enhanced performance of AlGaN solar-blind ultraviolet avalanche photodiodes through electric field optimization. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Enhanced sensitivity of fiber Bragg grating hydrogen sensor using flexible substrate. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Estimation of Porosity and Fluid Constituents from Neutron and Density Logs Using an Interactive Matrix Scale. SPWLA Annual Logging Symposium, OnePetro. onepetro.org. — Cited by: Downhole & borehole H2 sensing.
• Evaluation of in-situ optical loss of polyimide-coated optical fiber under hydrothermal environments. Geothermics. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Evaluation of the pulsed discharge helium ionization detector for the analysis of hydrogen and methane in breath. PubMed. pubmed.ncbi.nlm.nih.gov. — Cited by: Gas chromatography (lab, micro, and field GC).
• Evolution analysis of EUV radiation from laser-produced tin plasmas based on a radiation hydrodynamics model. Sci. Rep. 7, 45212. nature.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Experimental Comparison of Functionality between the Main Types of Methane Measurement Sensors in Mines. Energies 16(5), 2207, 10.3390/en16052207 (interferometric-sensor reliability/cross-sensitivity claim sourced from search-result snippet of this paper; direct full-text fetch was blocked in this research pass). mdpi.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Experimental speed-of-sound data and a fundamental equation of state for normal hydrogen optimized for flow measurements. ScienceDirect, sciencedirect.com (title/abstract-level; full text not retrievable in this session — 403). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Experimental Study on Active Thermal Protection for Electronic Devices Used in Deep−Downhole−Environment Exploration. Energies 16(3), 1231. mdpi.com. — Cited by: Downhole & borehole H2 sensing.
• Exploring natural hydrogen hotspots: a review and soil-gas survey design for identifying seepage. Geoenergy / Lyell Collection, lyellcollection.org (title-level; full text 403 in this session; multi-gas co-occurrence context via ResearchGate summary researchgate.net). — Cited by: Fiber-optic & chemochromic hydrogen sensors, IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies, Raman spectroscopy (spontaneous, gas phase), Catalytic pellistors, Thermal conductivity & acoustic (speed of sound) sensors, Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Gas chromatography (lab, micro, and field GC), Soil-gas surveys: hardware, protocols & survey design.
• Eye-readable plasmonic hydrogen sensor based on Au@Pd nanoparticle aggregation. ACS Sensors. 10.1021/acssensors.2c01471 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Fabry–Pérot Cavities with Suspended Palladium Membranes on Optical Fibers for Highly Sensitive Hydrogen Sensing. Molecules. pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Fast hydrogen detection via plasmonic metal-insulator-metal technology. Applied Optics, opg.optica.org. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• FBG Arrays for Quasi-Distributed Sensing: A Review. Photonic Sensors. link.springer.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Femtosecond laser fabricated micro Mach-Zehnder interferometer with Pd film as sensing materials for hydrogen sensing. Optics Letters 37(11), 1940. opg.optica.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Femtosecond two-photon laser-induced fluorescence imaging of atomic hydrogen in a laminar methane–air flame assisted by nanosecond repetitively pulsed discharges. Plasma Sources Sci. Technol.. iopscience.iop.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Femtosecond two-photon LIF imaging of atomic hydrogen in high-pressure methane-air flames. Proc. Combust. Inst.. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Fiber for Remote Sensing: Downhole sensing applications enhanced by specialty optical fibers, Laser Focus World. laserfocusworld.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Fiber optic hydrogen sensor based on a Fabry–Perot interferometer with a fiber Bragg grating and a nanofilm. Lab on a Chip. pubs.rsc.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Fiber optic hydrogen sensor based on an etched Bragg grating coated with palladium. Applied Optics 54(35), 10342. opg.optica.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Fiber Optical Hydrogen Sensor Based on WO3-Pd2Pt-Pt Nanocomposite Films. Nanomaterials 11(1), 128. ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• FIBER OPTICS: Overcoming Hydrogen Darkening. Journal of Petroleum Technology / SPE. jpt.spe.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Fiber-Enhanced Raman Spectroscopy for Trace-Gas Sensing in the High-Concentration Gas Background With an Anti-Resonant Hollow Core Fiber, Frontiers in Physics, 2022. frontiersin.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Fiber-optic evanescent-wave hydrogen gas sensor using palladium-supported tungsten oxide. Sensors and Actuators B: Chemical. researchgate.net. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Fiber-tip Fabry–Pérot interferometer with a graphene–Au–Pd cantilever for trace hydrogen sensing. Lab on a Chip. pubs.rsc.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Field calibration of a cluster of low-cost commercially available sensors for air quality monitoring. Part B: NO, CO and CO2. Sensors and Actuators B (2017, search-snippet summary re: multi-linear regression bias reduction). sciencedirect.com; complementary despiking/QC methodology: Mazama Science AirSensor package documentation, “Outlier Detection with the Hampel Filter.” mazamascience.github.io; “Baseline Drift Estimation for Air Quality Data Using Quantile Trend Filtering” (arXiv, 2019). arxiv.org. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Field-Effect Transistors for Gas Sensing. IntechOpen, intechopen.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• First detection of industrial hydrogen emissions using high precision mobile measurements in ambient air. Scientific Reports / PMC11480439, pmc.ncbi.nlm.nih.gov (fetched 2026-07-04): background H₂ mole fraction ~0.5 ppm / ~530 ppb, GC-PDHID precision <2 ppb. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Environmental covariance & signal interpretation.
• Fluke ii910 retail pricing (new unit, $28,549.99). business.walmart.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Fully eco-friendly H2 sensing device based on Pd-decorated graphene. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors.
• Gas and vapor phase detection of chemical threats on cooled SERS substrates, Talanta/related, 2024–2025 (sub-ppm HCN/Tabun on cooled substrate; 100 ppm general vapor-phase SERS ceiling; film-oxidation lifetime limit). sciencedirect.com; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Gas detection sensitivity of hybrid fs/ps and fs/ns CARS, Optics Letters 47(6):1470, 2022. opg.optica.org; OSTI record osti.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Gas permeable chemochromic compositions for hydrogen sensing. US Patent Application 20070224081A1. patents.google.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Gas Sensor Based on Surface Enhanced Raman Scattering, Sensors, 2021 (ethanol vapor SERS, Si/Ag NP substrate, FDTD enhancement 10⁶–10⁸). pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Gas-Liquid Separation Processes for Mud Logging Systems. ResearchGate record. researchgate.net. — Cited by: Mud-gas logging for H2 while drilling.
• General palladium hydrogen-absorption/solubility background. US Patent 9,618,465. image-ppubs.uspto.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• General permeation-tube generation performance summary (0.1–200 ppm, ~±1% precision/accuracy) via search-result synthesis of permeation-device literature, e.g. ASTM STP on trace gas calibration systems using permeation devices. store.astm.org. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Geologic hydrogen: a review of resource potential, subsurface dynamics, exploration, production, transportation, and research opportunities. Energy & Environmental Science, RSC Publishing, 10.1039/D5EE02910D pubs.rsc.org (title-level; full text 403 in this session; downhole electronics temperature-limit claim, ~175 °C Si/SiC vs. ~400 °C target, via search synthesis of this source). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Graphene-Based Hydrogen Gas Sensors: A Review. Processes 8(5), 633, MDPI. mdpi.com. — Cited by: 2D-material & nanostructure FET sensors.
• Greatly etched fiber Bragg grating hydrogen sensor with Pd/Ni composite film as sensing material. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Grolltex graphene gas sensor applications. grolltex.com; grolltex.com. — Cited by: 2D-material & nanostructure FET sensors.
• H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions. (background atmospheric H2 context, ~500–550 ppb consistent with 0.53 ppm figure). pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors, Palladium resistive & nanomaterial sensors.
• H2S Scavenging Capacity and Rheological Properties of Water-Based Drilling Muds. PMC. pmc.ncbi.nlm.nih.gov. — Cited by: Mud-gas logging for H2 while drilling.
• High conductivity graphite paste for radio frequency identification tag with wireless hydrogen sensor based on CeO2–Fe2O3–graphene oxide. RSC Advances. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• High photon flux table-top coherent extreme-ultraviolet source. Nature Photonics. nature.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• High-density fiber Bragg grating array enabling fully distributed sensing with sub-millimeter spatial resolution. Optics Letters 51(1), 117. opg.optica.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• High-performance hydrogen detection of nanoarrays based on plasmonic enhancement mechanism, Scientific Reports, 2025 (LSPR-based Pd hydrogen sensing, not Raman). nature.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• High-Performance Nanostructured Palladium-Based Hydrogen Sensors—Current Limitations and Strategies for Their Mitigation. ACS Sensors 5(11). pmc.ncbi.nlm.nih.gov (citing U.S. DOE EERE Fuel Cell Technologies Office, Multi-Year Research, Development, and Demonstration Plan, 2011–2020, for the DOE hydrogen safety-sensor performance targets). — Cited by: Why hydrogen is hard to sense, 2D-material & nanostructure FET sensors, Palladium resistive & nanomaterial sensors, Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Plasmonic & metamaterial sensors, Environmental covariance & signal interpretation.
• High-performance solar-blind AlGaN photodetectors. Bilkent University repository PDF. repository.bilkent.edu.tr. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• High-precision gas refractometer by comb-mode-resolved spectral interferometry. PMC6219595. ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• High-Precision Trace Hydrogen Sensing by Multipass Raman Scattering, Singh & Muller, Sensors 23(11):5171, 2023, DOI 10.3390/s23115171 (comparison Table 1: chemiresistor 0.01 ppm LOD/~20 s; Schottky diode 0.1 ppm/~10 s; MEMS 0.1 ppm/~2 s; IR absorption 1000 ppm/1 s; PARS 3.4 ppm/~10 s; FERS 4.7 ppm/1–100 s; CERS 0.069 ppm & other values/500–2500 s; this-work multipass cavity 0.06 ppm/600 s). pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• High-sensitivity and fast-response fiber-tip Fabry–Pérot hydrogen sensor with suspended palladium-decorated graphene. Nanoscale. pubs.rsc.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• High-temperature (1000–7000 K) collision-induced absorption of H2 pairs computed from first principles, with application to cool and dense stellar atmospheres. sciencedirect.com. — Cited by: Why hydrogen is hard to sense.
• High-Temperature SAW Wireless Strain Sensor with Langasite. Sensors 15(11):28531, PMC4701294. pmc.ncbi.nlm.nih.gov (does not establish the langasite TCF ≈−0.84 to −1 ppm/°C or >1000 °C wired-operation claims cited elsewhere on this page). — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Highly accurate transition frequencies in the H2 Lyman and Werner absorption bands. (Academia.edu PDF). academia.edu. — Cited by: Why hydrogen is hard to sense, UV/EUV electronic transitions & fluorescence — the physics veto.
• Highly accurate transition frequencies in the H2 Werner and Lyman absorption bands. (ResearchGate PDF). researchgate.net. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Highly Fast Response of Pd/Ta2O5/SiC and Pd/Ta2O5/Si Schottky Diode-Based Hydrogen Sensors. PMC. ncbi.nlm.nih.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Downhole & borehole H2 sensing.
• Highly responsive hydrogen sensor based on Pd nanoparticle-decorated transfer-free 3D graphene. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors.
• Highly Sensitive Dissolved Hydrogen Sensor Based on Side-Polished Fiber Bragg Grating. IEEE. ieeexplore.ieee.org. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Highly sensitive hydrogen sensor based on an in-fiber Mach-Zehnder interferometer with polymer infiltration and Pt-loaded WO3 coating. Optics Express 29(3), 4147. opg.optica.org. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging, Fiber-optic & chemochromic hydrogen sensors.
• Highly Sensitive Optical Sensor for Hydrogen Gas Based on a Polymer Microcylinder Ring Resonator. Sens. Actuators B, and related microbottle-resonator Pd-WO₃/PDMS hydrogen-sensor synthesis (0.0312–1% H₂ range, up to 140 pm/% sensitivity, ~60 ppm LOD reported for one design). sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Highly sensitive two-dimensional MoS2 gas sensor decorated with Pt nanoparticles. Royal Society Open Science 5(12), 181462. royalsocietypublishing.org (does not support the claim; this paper reports NH3/H2S sensing only, not H2). — Cited by: 2D-material & nanostructure FET sensors.
• HITRAN isotopologue metadata (H2, CH4 abundances / partition functions). hitran.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Hnat 2024 — Pioneering Aerial Natural Hydrogen Detection: Xcalibur Smart Mapping’s Breakthrough with Raman LiDAR Technology (link dead — URL now returns 404; page was indexed by search engines with matching title/content as of this review, but no live mirror or archived copy could be retrieved). hnatworldsummit.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Hole-mask colloidal nanolithography combined with tilted-angle-rotation evaporation: A versatile method for fabrication of low-cost and large-area complex plasmonic nanostructures and metamaterials. Beilstein Journal of Nanotechnology 5, 682–691. pmc.ncbi.nlm.nih.gov. — Cited by: Plasmonic & metamaterial sensors.
• How to measure hydrogen in natural gas with Raman spectroscopy, Endress+Hauser process-automation article. endressprocessautomation.com. — Cited by: Why hydrogen is hard to sense, Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering for high-speed gas-phase thermometry. researchgate.net. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Hydride formation thermodynamics and hysteresis in individual Pd nanocrystals. livrepository.liverpool.ac.uk. — Cited by: Plasmonic & metamaterial sensors.
• Hydrogen Balmer α line behavior in Laser-Induced Breakdown Spectroscopy depth scans of Au, Cu, Mn, Pb targets in air. Spectrochim. Acta B. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Hydrogen Darkening. distributedsensing.net. distributedsensing.net. — Cited by: Fiber-optic & chemochromic hydrogen sensors, Downhole & borehole H2 sensing.
• Hydrogen detection method using gas sensor having a metal oxide layer. US Patent, image-ppubs.uspto.gov (does not support the claim). — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Hydrogen Detection Tape Saves Time and Lives. NASA Spinoff 2016. spinoff.nasa.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Hydrogen diffusion and solubility in palladium thin films. University of Kentucky. scholars.uky.edu. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Hydrogen effects on the mechanical properties of nanocrystalline free-standing Palladium thin films. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Hydrogen Gas Detection by Mini-Raman Lidar. IntechOpen chapter (the chapter’s DPSS-laser compact-lidar sub-system is reported at 1–100% H₂ concentration range and <50 m detectable distance; the mini-Raman lidar variant specifically is reported at 20–30 m range) — cited here only to distinguish Raman lidar (selective, vibrational) from Rayleigh-scattering approaches (non-selective); full Raman physics covered in Raman spectroscopy. intechopen.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Hydrogen gas sensitive semiconductor sensor. US Patent, image-ppubs.uspto.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, How the sensor families actually differ: a transduction decoder.
• Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures. PMC3386698. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors.
• Hydrogen Leak Detection Using Laser-Induced Breakdown Spectroscopy. Appl. Spectrosc. 59(3), 348–353; PubMed 15901317. pubmed.ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Hydrogen leakage diagnosis and visualization of density and pressure using Background Oriented Schlieren with Dual-Channel MGR-Net. Int. J. Hydrogen Energy. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Hydrogen Sensing at Room Temperature Using Flame-Synthesized Palladium-Decorated Crumpled Reduced Graphene Oxide Nanocomposites. ACS Sensors. 10.1021/acssensors.0c01040 pubs.acs.org. — Cited by: 2D-material & nanostructure FET sensors.
• Hydrogen Sensing Mechanism of WS2 Gas Sensors Analyzed with DFT and NAP-XPS. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Hydrogen Sensing Using Thin-Film Perfect Light Absorber. ACS Photonics. 10.1021/acsphotonics.9b00764 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Hydrogen Sensors Based on Flexible Carbon Nanotube-Palladium Composite Sheets Integrated with Ripstop Fabric. ACS Omega (2019/2020). pmc.ncbi.nlm.nih.gov; pubs.acs.org. — Cited by: 2D-material & nanostructure FET sensors.
• Hydrogen signatures in the Bourakebougou field, Mali: A petrophysical log analysis. ScienceDirect. sciencedirect.com. — Cited by: Downhole & borehole H2 sensing.
• Hydrogen solubility in water and brine: A simplified Henry’s law method verified against experimental data. Fuel. 10.1016/j.fuel.2026.139371 sciencedirect.com. — Cited by: Mud-gas logging for H2 while drilling, Downhole & borehole H2 sensing.
• HyTerra provide update on Nemaha Project. Global Hydrogen Review. globalhydrogenreview.com. — Cited by: Mud-gas logging for H2 while drilling.
• Improved performance of fiber-optic hydrogen sensor of porous Pt/WO3 based on ZIF-8. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Improvement of the Detection Sensitivity for Tunable Diode Laser Absorption Spectroscopy: A Review. Front. Phys. 10, 853966. frontiersin.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Improving Hydrogen Selectivity in Semiconductor Metal Oxide Gas Sensors with Cellulose Nanocrystal Membranes. PMC12670992. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors.
• Improving the Detection Limit in a Capillary Raman System for In Situ Gas Analysis by Means of Fluorescence Reduction, Sensors 15(9):23110, 2015. pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Improving the efficiency of gasochromic response by using a dual sample system with WO3 thin films with Pd and Pt catalysts. Scientific Reports. nature.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• In-line Mach-Zehnder Interferometer and FBG with Pd film for simultaneous hydrogen and temperature detection. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging, Fiber-optic & chemochromic hydrogen sensors.
• In-Well Degassing Issues for Measurements of Dissolved Gases in Groundwater. PubMed. pubmed.ncbi.nlm.nih.gov. — Cited by: Downhole & borehole H2 sensing.
• Industrial hydrogen safety references on flammability. What’s LEL? Lower Explosive Limit Guide for Safety Pros. hseblog.com; Industrial Monitor Direct, “Hydrogen Gas LEL Limits & Exposure Safety.” industrialmonitordirect.com. — Cited by: Geologic context: the measurement problem in H2 exploration, Concentration units: ppm, ppb, %LEL, mg/m³, and partial pressure.
• Innovative Hydrogen Leak Detection Tape Earns Prestigious Awards. NASA. nasa.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Intelligent Optical to Develop Hydrogen Sensor for Ford’s Fuel Cell. Photonics.com. photonics.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Interface pinning causes the hysteresis of the hydride. OSTI technical report (critical-point values). osti.gov. — Cited by: Palladium resistive & nanomaterial sensors.
• International Association for Hydrogen Safety. Small Burning Hydrogen Leaks in Industrial Plants: A Comparison of UV and IR Remote Imaging Detection. Hydrogen Safety journal, article 10.58895/hysafe.39 hysafejournal.org. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Intrinsically Safe Optical Fiber Hydrogen Sensor Using Pt-SiO2 Coated Long-Period Fiber Grating. Nanomaterials 16(2), 95. mdpi.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Ionization Cross Sections of Hydrogen Molecule by Electron and Positron Impact. PMC10970707. ncbi.nlm.nih.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Ionization Quantum Yields and Absorption Coefficients of Selected Compounds at 58.4 and 73.6–74.4 nm. PMC. pmc.ncbi.nlm.nih.gov; NIST, “Atomic Data for Helium (He)” (IP 24.587387 eV). physics.nist.gov. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Is Nebraska Geologic Hydrogen Site a Black Swan for Clean Energy?. thinc.blog. thinc.blog. — Cited by: Mud-gas logging for H2 while drilling.
• ISEA (International Safety Equipment Association) guidance as summarized in PK Safety / MSA blog sources (ref. 17); calibration-interval synthesis. gasdetection.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• ISEA / safety-industry guidance as summarized in. What Are Calibration and Bump Tests for Portable Gas Detectors. blog.msasafety.com; PK Safety, “OSHA Gas Meter Calibration Requirements.” pksafety.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Joint Committee for Guides in Metrology (JCGM). Evaluation of measurement data — Guide to the expression of uncertainty in measurement. (GUM), JCGM 100:2008. bipm.org; full text: ncc.nesdis.noaa.gov. — Cited by: Calibration, drift & QA/QC for H2 field programs, Figures of merit: how to compare any two H2 sensors honestly.
• Laboratory and field evaluation of a low-cost methane sensor and key environmental factors for sensor calibration. PMC10100561. ncbi.nlm.nih.gov. — Cited by: Environmental covariance & signal interpretation, Reading a sensor datasheet.
• Lag Time for Drilling Business and How to Calculate Theoretical Lag Time. Drilling Formulas. drillingformulas.com; “Lag Time In Drilling | Actual & Calculations.” Drilling Manual. drillingmanual.com. — Cited by: Downhole & borehole H2 sensing.
• Langasite as Piezoelectric Substrate for Sensors in Harsh Environments: Investigation of Surface Degradation under High-Temperature Air Atmosphere. PMC8434677. pmc.ncbi.nlm.nih.gov (does not establish the langasite TCF ≈−0.84 to −1 ppm/°C or >1000 °C wired-operation claims cited elsewhere on this page). — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Laser plasma diagnostics and self-absorption measurements of the Hβ Balmer series line. Spectrochim. Acta B. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Laser-induced breakdown spectroscopy for the measurement of air humidity using spectral line intensity ratio. RSC Advances. pubs.rsc.org; PMC full text: ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging, UV/EUV electronic transitions & fluorescence — the physics veto.
• Laser-induced fluorescence of hydrogen via the E,F¹Σg⁺→B¹Σu⁺ transition: Rotational-state-dependent collisional quenching. Chem. Phys. Lett.. sciencedirect.com. — Cited by: Why hydrogen is hard to sense, UV/EUV electronic transitions & fluorescence — the physics veto.
• Long-term drift behavior in metal oxide gas sensor arrays: a one-year dataset from an electronic nose. Scientific Data. nature.com. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation.
• Low profile, high temperature, hydrogen tolerant optical sensing cable (patent; describes H2-induced fiber loss mechanism and reversibility). image-ppubs.uspto.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Low-Cost Hydrogen Sensor in the ppm Range with Purely Optical Readout. ACS Sensors. 10.1021/acssensors.9b02314 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Measurement of Palladium Hydride and Palladium Deuteride Isotherms Between 130 K and 393 K. researchgate.net. — Cited by: Environmental covariance & signal interpretation.
• Measurement of the concentration distribution of hydrogen jets using adaptive stream stripe-background oriented schlieren (ASS-BOS). Int. J. Hydrogen Energy. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Measurements of refractive-index dispersion in gases with a two-wavelength one-path interferometer. J. Opt. Soc. Am. 73(12), 1836. opg.optica.org. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Membrane Inlet Mass Spectrometer for the Quasi-Continuous On-Site Analysis of Dissolved Gases in Groundwater. Environmental Science & Technology 46(15), 8288. pubs.acs.org; pubmed.ncbi.nlm.nih.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Dissolved H2 in groundwater & formation water.
• MEMS based highly sensitive dual FET gas sensor using graphene decorated Pd-Ag alloy nanoparticles for H2 detection. Scientific Reports. nature.com; pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• MEMS hydrogen gas sensor with wireless quartz crystal resonator. Sensors and Actuators B: Chemical, Tohoku University group. sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Metal Oxide Gas Sensors, a Survey of Selectivity Issues Addressed at the SENSOR Lab, Brescia (Italy). PMC5421674. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors, Sensor arrays, e-noses & machine-learning selectivity.
• Metal Oxide Gas Sensors: Sensitivity and Influencing Factors. PMC3264469. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors.
• Metal-insulator-metal sensors monitoring charge flow during thermal desorption. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Methane infrared absorption. (HITRAN-derived CH4 ν3-band line intensity, via hitran.ioa.ru). climateauditor.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Methods of operation of electrochemical gas sensors. (patent document containing the capillary-limited diffusion current derivation, $i_L = nFADC_\infty/l$). image-ppubs.uspto.gov. — Cited by: Electrochemical cells (amperometric & potentiometric), Figures of merit: how to compare any two H2 sensors honestly.
• Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber. ncbi.nlm.nih.gov; Ultra-low background Raman sensing using a negative-curvature fibre and no distal optics, PMC7065639. pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Micromachined Thermal Gas Sensors — A Review. PMC9860855, pmc.ncbi.nlm.nih.gov. — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Miniature and Fieldable Mass Spectrometers: Recent Advances. PMC5364034. pmc.ncbi.nlm.nih.gov. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Minimum Detection Concentration of Hydrogen in Air Depending on Substrate Type and Design of the 3ω Sensor. PMC10648048 (see [10]) — substrate comparison data (SiO₂ ~18%, polyimide 3–4%, suspended 0.3–0.35%, theoretical floor ~1400 ppm). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Mitsubishi Heavy Industries Invests in Koloma, a US-Based Geologic Hydrogen Exploration Startup. Mitsubishi Heavy Industries, 2024. mhi.com. — Cited by: Downhole & borehole H2 sensing.
• Mixed potential type hydrogen sensor. Ionics, Springer. link.springer.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Modeling Interfacial Interaction between Gas Molecules and Semiconductor Metal Oxides: A New View Angle on Gas Sensing. PMC9685467. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors.
• Molecular hydrogen in atmosphere. (tropospheric H2 background ~0.53 ppmv). researchgate.net; Weybourne Atmospheric Observatory H2 record: tandfonline.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Monitoring the chemical changes in Pd induced by hydrogen absorption using microcantilevers. PubMed 12801698. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• MOSFE-Capacitor Silicon Carbide-Based Hydrogen Gas Sensors. PMC, ncbi.nlm.nih.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Mud gas isotope logging (MGIL) assists in oil and gas drilling operations. Oil & Gas Journal. ogj.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Multigas Analysis by Cavity-Enhanced Raman Spectroscopy for Power Transformer Diagnosis, Analytical Chemistry, 2020 (Z-shaped four-mirror dense multipass cavity description). pubs.acs.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Multipass Gas Cells — Pfund, White, Herriott, circular multipass cells, RP Photonics Encyclopedia. rp-photonics.com; Thorlabs Herriott Cells product page. thorlabs.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• N2-cooled THz quartz-enhanced photoacoustic sensor operating in pulsed mode for hydrogen sulfide detection in the part-per-billion concentration range. researchgate.net. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Nanofiber enhanced stimulated Raman spectroscopy for ultra-fast, ultra-sensitive hydrogen detection with ultra-wide dynamic range. Optica 6(5), 570. opg.optica.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• nanoplus Nanosystems and Technologies GmbH. Distributed Feedback Lasers 2200 nm – 2600 nm. nanoplus.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Nanoscale Analysis of Sulfur Poisoning Effects on Hydrogen Sorption in Single Pd Nanoparticles. ACS Nano. pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense, Enhanced Raman (CERS, fiber, SERS & coherent Raman), Fiber-optic & chemochromic hydrogen sensors, Plasmonic & metamaterial sensors.
• Nanostructured Pd–Au based fiber optic sensors for probing hydrogen concentrations in gas mixtures. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• NASA Awards Intelligent Optical Systems Inc. $600,000 Follow-On Contract to Develop Fiber Optic Hydrogen Leak Detection System. SpaceNews. spacenews.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• NASA Technical Reports Server record of the same paper. ntrs.nasa.gov. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Natural Hydrogen Breakthrough: HyTerra Reports 83% Concentration in Kansas Drilling. Hydrogen Industry Leaders. hydrogenindustryleaders.com. — Cited by: Mud-gas logging for H2 while drilling.
• Natural Hydrogen — Xcalibur Smart Mapping (H-MAS description, Raman Scattering Spectroscopy mechanism, FALCON AGG integration). xcaliburmp.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Natural isotope fingerprinting of produced hydrogen and its potential applications to the hydrogen economy. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Isotopic & genetic fingerprinting.
• NETL and Partners Develops Novel Embedded Sensors for Subsurface Wellbore Integrity. National Energy Technology Laboratory. netl.doe.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• NETL Patents Fiber Optic Sensor Technology for Hydrogen Leak Detection. NETL. netl.doe.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• New experimental measurements of the Collision Induced Absorptions of H2-H2 and H2-He in the 3600–5500 cm−1 spectral range from 120 to 500 K. sciencedirect.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• New method for calibration of a quadrupole mass spectrometer for hydrogen isotopes measurements. Fusion Engineering and Design. sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Novel Calibration Approach for Monitoring Aerosol Hydrogen Isotopes Using Laser-Induced Breakdown Spectroscopy for Molten Salt Reactor Off-Gas Streams. Sensors 23(24), 9797; PMC10747517. ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Numerical Modeling and Experimental Validation by Calorimetric Detection of Energetic Materials Using Thermal Bimorph Microcantilever Array. Sensors 15(9):21785. mdpi.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Odour Samples Degradation During Detention in Tedlar® Bags. PMC. pmc.ncbi.nlm.nih.gov. — Cited by: Gas chromatography (lab, micro, and field GC).
• On the determination of plasma electron number density from Stark broadened hydrogen Balmer series lines in Laser-Induced Breakdown Spectroscopy experiments. Spectrochim. Acta B. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• On the Polarizability of the Hydrogen Molecule. researchgate.net. — Cited by: Why hydrogen is hard to sense.
• On-chip ultrasensitive and rapid hydrogen sensing based on plasmon-induced hot electron–molecule interaction. Light: Science & Applications. 10.1038/s41377-023-01123-4 nature.com. — Cited by: Plasmonic & metamaterial sensors.
• On-line multi-gas component measurement in the mud logging process based on Raman spectroscopy combined with a CNN-LSTM-AM hybrid model. PubMed. pubmed.ncbi.nlm.nih.gov. — Cited by: Mud-gas logging for H2 while drilling.
• Optical Fiber Grating Hydrogen Sensors: A Review. Sensors 17(3), 577. pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense, Fiber-optic & chemochromic hydrogen sensors, Figures of merit: how to compare any two H2 sensors honestly.
• Optical Fiber Hydrogen Sensor Based on π-Phase-Shifted Grating and Sputtered Pd/Hf Composite Film. Photonic Sensors. link.springer.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Optical fibers present opportunities and challenges for geophysical applications. Offshore Magazine. offshore-mag.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Optical hydrogen sensing with high-Q guided-mode resonance of Al2O3/WO3/Pd nanostructure. Scientific Reports. nature.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Optimization of the Composition of PdAuCu Ternary Alloy Nanoparticles for Plasmonic Hydrogen Sensing. ACS Applied Nano Materials. 10.1021/acsanm.1c01242 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Optimizing Helium Exploration: Noble Gas Isotopes as Probes for Migration–Enrichment Processes. Energies 18(16), 4218. mdpi.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Helium, noble gases & co-tracers, Isotopic & genetic fingerprinting.
• Origin of Baseline Drift in Metal Oxide Gas Sensors: Effects of Bulk Equilibration. Chemosensors (MDPI) 10(5), 171. mdpi.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Oxygen effect on the operation of the MOS-structure-based hydrogen sensor. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Ozone Hartley band peak cross section values (1.1476×10⁻¹⁷ cm² Hearn 1961; 1.145×10⁻¹⁷ cm² HITRAN 2016 at 253.65 nm; 1.1329×10⁻¹⁷ cm² consensus). Recommendation of a consensus value of the ozone absorption cross-section at 253.65 nm. Metrologia. iopscience.iop.org; AMT, “Accurate measurements of ozone absorption cross-sections in the Hartley band” (2015). amt.copernicus.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Palladium (Pd) coated fiber optic hydrogen sensors: A review. Optics & Laser Technology. sciencedirect.com. — Cited by: Palladium resistive & nanomaterial sensors.
• Palladium nanoparticle-decorated multi-layer Ti3C2Tx dual-functioning as a highly sensitive hydrogen gas sensor and hydrogen storage. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Palladium-based optical fiber Bragg grating hydrogen sensors: A comprehensive review. Optics & Laser Technology (ScienceDirect), 2024. sciencedirect.com. — Cited by: Why hydrogen is hard to sense, Downhole & borehole H2 sensing.
• Palladium-Based Plasmonic Perfect Absorber in the Visible Wavelength Range and Its Application to Hydrogen Sensing. Nano Letters. 10.1021/nl202489g pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Palladium/Graphene Oxide Nanocomposite for Hydrogen Gas Sensing Applications Based on Tapered Optical Fiber. Sensors. ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Paragraf GHS (Graphene Hall Sensor) product line:. paragraf.com; store.paragraf.com; GHS-series brochure: paragraf.com. — Cited by: 2D-material & nanostructure FET sensors.
• Passivation Strategies for Far-Ultraviolet Al Mirrors Using Plasma-Based AlF3 Processing. Chem. Mater.. pmc.ncbi.nlm.nih.gov. — Cited by: Why hydrogen is hard to sense.
• Passive Leak Detection Using Commercial Hydrogen Colorimetric Indicator. NREL/OSTI Technical Report. osti.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Pd films on soft substrates: a visual, high-contrast and low-cost optical hydrogen sensor. Light: Science & Applications 7, 8. 10.1038/s41377-018-0114-x nature.com. — Cited by: Plasmonic & metamaterial sensors.
• Pd nanocube-decorated MoS2 hybrid nanostructures for fast and reliable room-temperature hydrogen detection. International Journal of Hydrogen Energy. sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors.
• Pd-Nanoparticle-Decorated Multilayered MoS2 Sheets for Highly Sensitive Hydrogen Sensing. Chemosensors 11(11), 550. mdpi.com. — Cited by: 2D-material & nanostructure FET sensors.
• Pd/Ag coated fiber Bragg grating sensor for hydrogen monitoring in power transformers. PubMed. pubmed.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Pd/Au nanofilms based tilted fiber Bragg grating hydrogen sensor. Optics Communications. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Performance Degradations of MISFET-Based Hydrogen Sensors with a Pd-Ta2O5-SiO2-Si Structure During Long-Term Operation. Sensors 19(8), 1855, DOI 10.3390/s19081855. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Performance of fiber Bragg grating hydrogen sensor coated with Pt-loaded WO3 coating. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Performance of Intrinsic and Modified Graphene for the Adsorption of H2S and CH4: A DFT Study. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Photoresponsive and Gas Sensing Field-Effect Transistors based on Multilayer WS2 Nanoflakes. Scientific Reports (srep05209). nature.com. — Cited by: 2D-material & nanostructure FET sensors.
• Picocavity-enhanced Raman Spectroscopy of Physisorbed H2 and D2 Molecules, Shiotari, Liu, Trenins, Sugimoto, Wolf, Rossi, Kumagai, arXiv:2411.10994, 2024 (Fritz Haber Institute; 10 K, sub-nm Ag tip–Ag(111) gap, single-molecule detection). arxiv.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• PLL-Based Readout Circuit for SiC-MOS Capacitor Hydrogen Sensors in Industrial Environments. PMC, ncbi.nlm.nih.gov. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Polarizability of molecular hydrogen and gas metrology. Phys. Rev. A 111, 012801. link.aps.org. — Cited by: Why hydrogen is hard to sense.
• Potentiometric hydrogen sensors based on yttria-stabilized zirconia electrolyte (YSZ) and CdWO4 interface. ScienceDirect. sciencedirect.com. — Cited by: Downhole & borehole H2 sensing.
• Precise multispecies agricultural gas flux determined using broadband open-path dual-comb spectroscopy. Sci. Adv. pmc.ncbi.nlm.nih.gov. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Preparation of low-concentration H2 test gas mixtures in ambient air for calibration of H2 sensors. Atmospheric Measurement Techniques 17, 4081–. amt.copernicus.org. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Pressure-induced infrared absorption of hydrogen and hydrogen–foreign gas mixtures. cdnsciencepub.com. — Cited by: Why hydrogen is hard to sense.
• Production of 13.5 nm light with 5% conversion efficiency from 2 µm laser-driven tin microdroplet plasma. Appl. Phys. Lett. 123, 234101. pubs.aip.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Progress on AlGaN-based solar-blind ultraviolet photodetectors and focal plane arrays. Light: Sci. Appl. 10, 94. nature.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Propagating and localized surface plasmon resonance sensing — A critical comparison based on measurements and theory. Sensing and Bio-Sensing Research. sciencedirect.com. — Cited by: Plasmonic & metamaterial sensors.
• Pt and Pd as catalyst deposited by hydrogen reduction of metal salts on WO3 films for gasochromic application. Solar Energy Materials and Solar Cells. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Pt/GaN, Pt-AlGaN/GaN, and Pd/AlGaN/GaN HEMT hydrogen-sensing performance data. Sensitivity Factor 14,685. or “50 ppb” claims attributed to it elsewhere on this page. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• PubMed record of the same paper. pubmed.ncbi.nlm.nih.gov. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• QIMC Announces Major Natural Hydrogen Discovery in Nova Scotia. Record 5,558 ppm. Resource World Magazine. resourceworld.com. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Quality Isotope Analysis at the Wellsite: Two Case Studies that Validate GC-C-IRMS Mud Gas Isotope Logging for Deepwater Exploration and Development. SPE Annual Technical Conference and Exhibition. onepetro.org. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Quantification of the surface stress in microcantilever biosensors: Revisiting Stoney’s equation. researchgate.net. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Quantitative analysis of hydrogen isotope gas mixtures by low resolution quadrupole mass spectrometer. sciencedirect.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Quantitative determination of H2, HD, and D2 internal-state distributions by (2+1) resonance-enhanced multiphoton ionization. NASA Technical Reports Server. ntrs.nasa.gov. — Cited by: Why hydrogen is hard to sense.
• Quantitative Gas Analysis with Hiden’s QGA. AZoCleantech. azocleantech.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Quantitative measurement of atomic hydrogen in low-pressure methane flames using two-photon LIF calibrated by krypton. Combustion and Flame. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Quantitative Raman Spectroscopic Determination of the Composition, Pressure, and Density of CO2-CH4 Gas Mixtures, Chen et al, Journal of Spectroscopy, 2022 (pressure-dependent peak-position/broadening methodology directly analogous to H2 fluid-inclusion work). onlinelibrary.wiley.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Raman Gas Analysis with External Power Build-Up Cavity of Line-Narrowed 407-nm Laser Diode, Sensors 25(15):4600, 2025. mdpi.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Raman Gas Analyzer for Real-Time Gas Composition Monitoring, Chorpening, Thapa & Buric, NETL, DOE Hydrogen Program 2023 Annual Merit Review (AMR Project ID FE018) (link re-verified live as of 2026-07-04; content confirmed to match — NETL Raman Gas Analyzer, real-time H2 fuel-blend composition monitoring to 1000 psi, >1000x optical-waveguide Raman signal boost, US Patent 8,674,306; the. source PDF 404’d. caveat in the Vendors & products section above predates this re-check and is stale). hydrogen.energy.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Raman Gas Sensor Based on Metal-Coated Capillary Cell, Bulletin of the Russian Academy of Sciences: Physics, 2023. link.springer.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Raman line positions in molecular hydrogen: H2, HD, HT, D2, DT, and T2, Journal of Molecular Spectroscopy. sciencedirect.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Raman Natural Gas Analyzer: Effects of Composition on Measurement Precision, Petrov, Matrosov, Zaripov, Tanichev, Sensors 22(9), 2022 (532 nm 1.5 W laser, Hamamatsu S10141 CCD, H2 LOD 4.2 ppm at 25 atm/300 K, alkane cross-sensitivity quantification). pmc.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Raman Rxn4 analyzer powered by Kaiser Raman technology, Endress+Hauser. us.endress.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Raman Spectroscopy Instrument Pricing: A Comprehensive Guide (general market price banding, $20k–$200k new / $10k–$100k used / >$500k custom). excedr.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman), Raman spectroscopy (spontaneous, gas phase).
• Ramsay 1 and Ramsay 2, learnings from the first natural hydrogen exploration wells in Australia. The APPEA Journal, CSIRO Publishing, EP23119. publish.csiro.au. — Cited by: Mud-gas logging for H2 while drilling.
• Rapid ppb-Level Methane Detection Based on Quartz-Enhanced Photoacoustic Spectroscopy. Anal. Chem.. pubs.acs.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Rationally Designed PdAuCu Ternary Alloy Nanoparticles for Intrinsically Deactivation-Resistant Ultrafast Plasmonic Hydrogen Sensing. ACS Sensors. 10.1021/acssensors.9b00610 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Reactions of hydrogen at the interface of palladium-titanium dioxide Schottky diodes as hydrogen sensors. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Recent Advances in Chemoresistive Gas Sensors Using Two-Dimensional Materials. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Record 96.1% Hydrogen Found in HyTerra’s Kansas Well. Discovery Alert. discoveryalert.com.au. — Cited by: Mud-gas logging for H2 while drilling.
• Redesigning protonic ceramic electrochemical cells to lower the operating temperature. Science Advances 2025. science.org. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• Reducing Humidity Response of Gas Sensors for Medical Applications: Use of Spark Discharge Synthesis of Metal Oxide Nanoparticles. PMC6111941. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors, Environmental covariance & signal interpretation.
• Reference measurements of hydrogen’s dielectric permittivity. Molecular Physics 107(15); NIST publication record. nist.gov; tandfonline.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil. Sensors. pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• ResearchGate search-result summary of H2 Lyman/Werner band literature (band origins below 112 nm; B¹Σu⁺−X¹Σg⁺ and C¹Πu−X¹Σg⁺ assignments), incl. The Lyman and Werner bands of H2. researchgate.net. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Reversible doping of graphene field effect transistors by molecular hydrogen: the role of the metal/graphene interface. 2D Materials (2019/2020). 10.1088/2053-1583/ab0b23 Preprint: arxiv.org (does not support the ≈0.16 e Pd3-cluster→graphene charge-transfer figure cited to it in the Characteristic Numbers table). — Cited by: 2D-material & nanostructure FET sensors.
• Review of noble metal and metal-oxide-semiconductor based chemiresistive hydrogen sensors. sciencedirect.com. — Cited by: Why hydrogen is hard to sense.
• Review of SERS Substrates for Chemical Sensing. PMC5485789. ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Review of the Application of Schlieren Systems in the Field of Hydrogen and Hydrogen Blends. Energies 19(7), 1691, 10.3390/en19071691 (full text behind access restrictions in this research pass; cited for title/existence and topical scope only). mdpi.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• Review of the Status and Prospects of Fiber Optic Hydrogen Sensing Technology. Photonics 11(9), 473. mdpi.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Review on Hollow-Core Fiber Based Multi-Gas Sensing Using Raman Spectroscopy, Photonic Sensors, 2024 (700× enhancement of HC-PBGF vs. bulk Raman detection). link.springer.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Revision of ISO 19229 to support the certification of calibration gases for purity. Accreditation and Quality Assurance (2019, arXiv preprint). arxiv.org; link.springer.com. — Cited by: Calibration, drift & QA/QC for H2 field programs.
• Road Map of Semiconductor Metal-Oxide-Based Sensors: A Review. PMC10422562. pmc.ncbi.nlm.nih.gov. — Cited by: Metal-oxide (MOX) chemiresistors.
• Robust Colloidal Synthesis of Palladium–Gold Alloy Nanoparticles for Hydrogen Sensing. ACS Applied Materials & Interfaces. 10.1021/acsami.1c15315 pubs.acs.org. — Cited by: Plasmonic & metamaterial sensors.
• Room temperature operated hydrogen sensor using palladium coated on tapered optical fiber. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Rototranslational collision-induced absorption by H2-H2 pairs at temperatures from 600 to 7000 K. NASA Technical Reports Server. ntrs.nasa.gov. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Roughness effects on the hydrogen signal in laser-induced breakdown spectroscopy. Spectrochim. Acta B. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Same paper, open-access PMC version. pmc.ncbi.nlm.nih.gov (fetched 2026-07-04). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Sapphire-Derived Fiber Bragg Gratings for High Temperature Sensing. Crystals 11(8), 946, MDPI. mdpi.com. — Cited by: Downhole & borehole H2 sensing.
• SAW sensor based on highly sensitive nanoporous palladium thin film for hydrogen detection. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• SciAps / Malvern Panalytical Z-901 product documentation (element exclusion list including H). sciaps.com (link fixed — original German SciAps Z-series URL no longer resolves). — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• SciAps Z-903+ handheld LIBS rental listing (pricing context: $1,990/week, $3,990/2 weeks, $5,990/month). shop.xrfcompany.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• SciAps Z200c+ LIBS Analyzer. Golden Analyzer Supply product listing (price $4,755 as listed on the cited page at time of verification; comparable Z-902C+/Z-200C+ configurations are listed elsewhere at $13,900–$15,090 — price unresolved). goldenanalyzersupply.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Selective H2 Sensing Through Use of Palladium and Platinum-based Nanoparticle Functional Sensor Layers Integrated with Engineered Filter Layers. NETL. netl.doe.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Sensing Electronics for Downhole Drilling in Extreme Environments. labpartnering.org US Patent 11,680,476, image-ppubs.uspto.gov. — Cited by: Why hydrogen is hard to sense, Metal-oxide (MOX) chemiresistors, Thermal conductivity & acoustic (speed of sound) sensors, Work-function devices: MIS, MIM, Schottky diodes & GasFETs, Downhole & borehole H2 sensing.
• Sensing Hydrogen Seeps in the Subsurface for Natural Hydrogen Exploration. MDPI Applied Sciences 12(13):6383, mdpi.com (title-level; full text 403 in this session); selectivity (K > 1000) and stability (<1 ppm/day) criteria and GA5000 field methodology via search synthesis, also summarized at ResearchGate researchgate.net. — Cited by: Why hydrogen is hard to sense, Thermal conductivity & acoustic (speed of sound) sensors, Electrochemical cells (amperometric & potentiometric), Calibration, drift & QA/QC for H2 field programs, Soil-gas surveys: hardware, protocols & survey design.
• Sensing mechanism of non-equilibrium solid-electrolyte-based chemical sensors. Journal of Solid State Electrochemistry, Springer. link.springer.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Sensing properties of palladium-gate MOS (Pd-MOS) hydrogen sensor based on plasma grown silicon dioxide. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs, How the sensor families actually differ: a transduction decoder.
• Sensitivity enhancement in high resolution stimulated Raman spectroscopy of gases with hollow-core photonic crystal fibers, Optics Letters 38(20):4074. opg.optica.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Short-term variability of atmospheric helium revealed through a cryo-enrichment method. Atmospheric Measurement Techniques 16, 1551. amt.copernicus.org (supports the 5.24 ppmv Glückauf figure; does not support the 5.222 ± 0.017 ppmv isotope-dilution figure also cited on this page). — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes), Helium, noble gases & co-tracers.
• Siloxane treatment of metal oxide semiconductor gas sensors in temperature-cycled operation – sensitivity and selectivity. Journal of Sensors and Sensor Systems 9, 283–292. jsss.copernicus.org. — Cited by: Metal-oxide (MOX) chemiresistors.
• SnO2 modified CsH2PO4 (CDP) protonic electrolyte for an electrochemical hydrogen pump. Energy Advances (RSC) 2025. 10.1039/D4YA00606B. — Cited by: Solid-electrolyte & high-temperature electrochemical sensors.
• SnO2-Co3O4 nanocomposite sensor: Achieving ultra-selective hydrogen detection in mixed gas environments. Sensors and Actuators B: Chemical. sciencedirect.com. — Cited by: Metal-oxide (MOX) chemiresistors, Sensor arrays, e-noses & machine-learning selectivity.
• Solid electrolyte gas sensors based on mixed potential principle – A review. sciencedirect.com. — Cited by: Electrochemical cells (amperometric & potentiometric).
• Solubility of H2-CH4 mixtures in brine at underground hydrogen storage thermodynamic conditions. Frontiers in Energy Research, 2024. 10.3389/fenrg.2024.1356491 frontiersin.org. — Cited by: Downhole & borehole H2 sensing.
• Standardization of surface potential measurements of graphene domains. Scientific Reports, srep02597. nature.com; and atmospheric H2 background (~0.5–0.53 ppmv): “Hydrogen in the atmosphere: Observations above a forest canopy in a polluted environment,” J. Geophys. Res. Atmos. (2003), agupubs.onlinelibrary.wiley.com; NOAA Global Monitoring Laboratory context, gml.noaa.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Start-up breaks temperature barrier in directional drilling, a challenge pursued for years. World Oil, 2026. worldoil.com. — Cited by: Downhole & borehole H2 sensing.
• Stimulated Raman Scattering in Hydrogen-Filled Hollow-Core Photonic Crystal Fiber, Benabid et al, Science 298(5592), 2002. science.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Stimulated Raman scattering metrology of molecular hydrogen, Communications Physics, 2023. nature.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Structure and Technological Parameters’ Effect on MISFET-Based Hydrogen Sensors’ Characteristics. MDPI, DOI 10.3390/s23063273. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Study of n value and α/β palladium hydride phase transition within the ultra-thin palladium composite membrane. Journal of Membrane Science. sciencedirect.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Sub-10 parts per billion detection of hydrogen with floating gate transistors built on semiconducting carbon nanotube film. Carbon. sciencedirect.com. — Cited by: 2D-material & nanostructure FET sensors, Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• Synergistic multicomponent Pd alloy films for high-performance hydrogen detection. ScienceDirect. sciencedirect.com. — Cited by: Downhole & borehole H2 sensing.
• T910 Hydrogen Detection Sensor. Technica Optical Components, LLC. technicasa.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Tapered Optical Fiber Functionalized with Palladium Nanoparticles by Drop Casting and Laser Radiation for H2 and Volatile Organic Compounds Sensing Purposes. Sensors. pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Technica Optical Components, LLC. company profile. RP Photonics. rp-photonics.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Temperature dependent characterization of optical fibres for distributed temperature sensing in hot geothermal wells. arXiv:1206.1853. arxiv.org. — Cited by: IR absorption spectroscopy (NDIR, TDLAS, CRDS, FTIR) & sensing proxies.
• Temperature-dependent work function shifts of hydrogenated/deuteriated palladium. sciencedirect.com. — Cited by: Work-function devices: MIS, MIM, Schottky diodes & GasFETs.
• The evolution of the hydrogen signal during GC-TCD analysis with helium carrier gas and PLOT columns. International Journal of Hydrogen Energy, sciencedirect.com (title-level via search). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors, Gas chromatography (lab, micro, and field GC).
• The Functionalized Single-Walled Carbon Nanotubes Gas Sensor With Pd Nanoparticles for Hydrogen Detection in the High-Voltage Transformers. Frontiers in Chemistry. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• The H Lyman-Alpha actinic flux in the middle atmosphere. researchgate.net. — Cited by: Why hydrogen is hard to sense.
• The high-accuracy spectroscopy of H2 rovibrational transitions in the (2-0) band near 1.2 μm. Phys. Chem. Chem. Phys.. pubs.rsc.org. — Cited by: Why hydrogen is hard to sense.
• The high-resolution absorption spectroscopy branch on the VUV beamline DESIRS at SOLEIL. J. Synchrotron Rad.. journals.iucr.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• The road ahead for ultrawide bandgap solar-blind UV photodetectors. J. Appl. Phys. 131, 150901. pubs.aip.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Theoretical Prediction of Electrical Conductivity Percolation of Poly(lactic acid)—Carbon Nanotube Composites in DC and RF Regime. ncbi.nlm.nih.gov (does not support the claim). — Cited by: 2D-material & nanostructure FET sensors.
• Theoretical Study of CO, NO, NO2, Cl2, and H2S Adsorption Interactions with PdO–Graphene Composites for Gas Sensor Applications. pmc.ncbi.nlm.nih.gov. — Cited by: 2D-material & nanostructure FET sensors.
• Thermal management of downhole electronics cooling in oil & gas well logging at high temperature. IEEE Conference Publication. ieeexplore.ieee.org. — Cited by: Electrochemical cells (amperometric & potentiometric), Downhole & borehole H2 sensing.
• Thermal Management of Downhole Oil and Gas Logging Sensors for HTHP Applications Using Nanoporous Materials. ASME ENIC2007, asmedigitalcollection.asme.org (title-level via search). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Thermal management systems for electronics using in deep downhole environment: A review. Applied Thermal Engineering (ScienceDirect), 2022. sciencedirect.com. — Cited by: Downhole & borehole H2 sensing.
• ThermoStar GSD 320 T2, 1–200 amu. datasheet excerpt. yumpu.com. — Cited by: Mass spectrometry (portable, membrane-inlet, isotopes).
• Tilted Fiber Bragg Grating Sensor Using Chemical Plating of a Palladium Membrane for the Detection of Hydrogen Leakage. Sensors 18(12), 4478 (MDPI, 2018). mdpi.com. — Cited by: Why hydrogen is hard to sense, Fiber-optic & chemochromic hydrogen sensors.
• Towards wafer-scale 2D material sensors. 2D Materials. 10.1088/2053-1583/adac73 iopscience.iop.org. — Cited by: 2D-material & nanostructure FET sensors.
• Trace gas detection of molecular hydrogen H2 by photoacoustic stimulated Raman spectroscopy (PARS), Analyst, 2012 (review of historical 1979-era 40 ppm and dye-laser 4.6 ppm PARS H2 demonstrations). pubs.rsc.org; PubMed pubmed.ncbi.nlm.nih.gov. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Trace Gas Monitoring by Hollow-Core Anti-Resonant Fiber-Enhanced Raman Spectroscopy with Sub-ppm Sensitivity, Photonics 12(11):1133, 2025. mdpi.com. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Two-dimensional imaging of molecular hydrogen in H2–air diffusion flames using two-photon laser-induced fluorescence. Opt. Lett. 16, 9, 660. opg.optica.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Two-Photon 205-nm Excitation of Atomic Hydrogen in Flames: Stimulated Emission, Time-Resolved Fluorescence, and Doppler-Free Excitation. in Twenty-Fifth Symposium (International) on Combustion. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Ultra-low power hydrogen sensing based on a palladium-coated nanomechanical beam resonator. Nanoscale, PubMed 22767251. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Ultra-low power palladium-coated MEMS resonators for hydrogen detection under ambient conditions. EPFL / TRANSDUCERS 2011. infoscience.epfl.ch. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Ultra-Weak Fiber Bragg Grating Sensing Network Coated with Sensitive Material for Multi-Parameter Measurements. Sensors. ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Ultrasensitive and fast single wavelength plasmonic hydrogen sensing with anisotropic nanostructured Pd films (LSPR-based, not SERS). arxiv.org. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Ultrasensitive Detection of Hydrogen Molecules by (2+1) REMPI. eScholarship. escholarship.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Ultrasensitive detection of low-ppm H2S gases based on palladium-doped porous silicon sensors. pmc.ncbi.nlm.nih.gov. — Cited by: Palladium resistive & nanomaterial sensors.
• Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer. Sensors 20(4), 1191; PMC7070851. pmc.ncbi.nlm.nih.gov. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• University of Toronto Scarborough TraceS Lab. Thermal Conductivity Detector (TCD). utsc.utoronto.ca (title-level via search). — Cited by: Thermal conductivity & acoustic (speed of sound) sensors.
• Unveiling the potential of Ti3C2Tx MXene for gas sensing: recent developments and future perspectives. Materials Advances (RSC). 10.1039/D3MA00631J. pubs.rsc.org. — Cited by: 2D-material & nanostructure FET sensors.
• Vacuum ultraviolet high-reflectance aluminum mirrors on copper substrate for application in noble liquid time projection chambers. sciencedirect.com. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Vacuum-UV spectroscopy of interstellar ice analogs. II. Absorption cross-sections of nonpolar ice molecules. A&A; arXiv:1405.7802 (CH4 cross section 5.7×10⁻¹⁸ cm², 120–160 nm); search-result synthesis on H2S VUV absorption bands (40–160 nm major, 160–250 nm minor). arxiv.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Vibrational-rotational Raman spectrum of hydrogen (Q-branch line assignments at 4126/4143/4155/4161 cm⁻¹). researchgate.net. — Cited by: Enhanced Raman (CERS, fiber, SERS & coherent Raman).
• Visual Hydrogen Detection. Element One. elem1.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Visual hydrogen detector with variable reversibility. NASA Technical Reports Server, 20120014374. ntrs.nasa.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Visualization of hydrogen leak for electro-hydrogen coupled system based on Background Oriented Schlieren. Process Saf. Environ. Prot. 175, 437. sciencedirect.com. — Cited by: Exotic optical approaches: LIBS, interferometry, flame UV & imaging.
• VUV-absorption cross section of carbon dioxide from 150 to 800 K and applications to warm exoplanetary atmospheres. A&A 609, A34; arXiv:1709.08415 (corrected — arXiv:1502.07620 is a different, earlier Venot et al. preprint, “VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres,” not the cited A&A 2018 paper). aanda.org. — Cited by: UV/EUV electronic transitions & fluorescence — the physics veto.
• Water photolysis effect on the long-term stability of a fiber optic hydrogen sensor with Pt/WO3. Scientific Reports. nature.com. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• WO3 Thin-Film Optical Gas Sensors Based on Gasochromic Effect towards Low Hydrogen Concentrations. Materials 16(10), 3831. pmc.ncbi.nlm.nih.gov. — Cited by: Fiber-optic & chemochromic hydrogen sensors.
• Young’s modulus and hardness of Pd thin films. Thin Solid Films. sciencedirect.com. — Cited by: Acoustic-wave & MEMS mechanical sensors (SAW, QCM, cantilevers).
• Subterranean production of neutrons, ³⁹Ar and ²¹Ne: Rates and uncertainties. arXiv:1509.07436 (per-chain alpha yields U-238 = 8, U-235 = 7, Th-232 = 6; mean alpha energies 5.4–6.0 MeV). arxiv.org. — Cited by: Helium, noble gases & co-tracers.