Abstract: In various embodiments, both very high speed and very high sensitivity hydrogen detection is achieved by controlling water vapor concentration over the catalyst used to convert hydrogen in sample gas (e.g., ambient air) to water vapor, to provide a substantially stable water vapor mixing level at a target mixing ratio. The naturally-occurring water vapor in the sample gas, without further steps, typically would vary over time within a wide range (e.g., due to changing atmospheric conditions). By controlling a level of water vapor over the catalyst to be substantially equal to a target mixing ratio that is not too low as to impair response time, and not too high as to impair sensitivity, both very high speed and very high sensitivity can be provided.

Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.

Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by in a detector that divides sample gas into two flows by dividing the sample gas before dampening variation and converting hydrogen to water vapor at two different points. For example, a detector may receive sample gas that includes ambient water vapor and hydrogen, divide the sample gas into a chemical conversion flow and bypass flow, perform a first chemical conversion of hydrogen in the chemical conversion flow to water vapor, alternate between drying the converted chemical conversion flow or the bypass flow to produce a modulated flow, perform a second chemical conversion of hydrogen in the modulated flow to water vapor, measure water vapor in the converted modulated flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based thereon.

Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by chemically converting hydrogen to water vapor and then detecting the water vapor as a surrogate for the hydrogen. Detection may be enhanced by dampening variation in ambient water vapor and rapidly actively modulating a hydrogen-derived water vapor component. For example, the detector may receive sample gas that includes ambient water vapor and hydrogen, dry the sample gas to dampen variation in the ambient water vapor, divide the sample gas into a chemical conversion flow and a bypass flow, chemically convert hydrogen in the chemical conversion flow to water vapor, alternate between measuring water vapor in the converted chemical conversion flow or the bypass flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based on the hydrogen-derived water vapor signal.

Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.