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AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsMichael E. Webber, Ronald K. Hanson, Jay B. Jeffries
Estimating the term…
A system and method utilizing a radiation source with a wavelength near 2 μm (preferably 1993 nm) to measure the presence of ammonia, carbon dioxide and water vapor using spectroscopic techniques and a reduced measurement pressure is provided. Using radiation substantially near 2 μm enables one to interrogate the PP3(3)s ammonia transition at a frequency of 5016.977 cm−1, which is isolated from water and carbon dioxide interference; the P(32) carbon dioxide transition at 5017.030 cm−1, which is isolated from both ammonia and water interference, and a water transition at 5017.100 cm−1. Moreover, a tunable radiation source that can sweep over the aforementioned ammonia and carbon dioxide and water features can measure the concentrations of all three species simultaneously. Using a sub-atmospheric pressure substantially near 100 Torr decreases the pressure broadening of different spectroscopic transitions, thereby isolating different absorption features, enabling species-specific measurements without interference, yet retaining sufficient peak absorption.
A sensor system for measuring ammonia in an environment containing carbon dioxide and water vapor, comprising a radiation source to spectrally interrogate the PP3(3)s ammonia transition which occurs at a frequency substantially close to 5016.977 inverse centimeters and which is substantially isolated from interfering absorption from said carbon dioxide and said water vapor.
A method for measuring ammonia in an environment containing carbon dioxide and water vapor, comprising the steps of:
A sensor system having a single radiation source operating at a wavelength of substantially near 2 μm for simultaneously measuring a plurality of species along a single optical path in a gas mixture containing said plurality of species, including at least ammonia, carbon dioxide and water vapor, wherein the absorption transitions to be interrogated for said plurality of species are proximate in frequency such that the radiation source can be scanned or stepped in wavelength across the absorption transitions of said plurality of species within a single measurement cycle and wherein each one of said absorption transitions, including the PP3(3)s ammonia transition, a carbon dioxide transition, and a water vapor transition, is substantially isolated from interfering absorption of other species of said plurality of species.
A method for simultaneously measuring with a single radiation source operating at a wavelength of substantially near 2 μm a plurality of species along a single optical path in a gas mixture containing said plurality of species, including at least ammonia, carbon dioxide and water vapor, wherein the absorption transitions to be interrogated for said plurality of species are proximate in frequency such that the radiation source can be scanned or stepped in said wavelength across the absorption transitions of said plurality of species within a single measurement cycle and wherein each one of said absorption transitions, including the PP3(3)s ammonia transition, a carbon dioxide transition, and a water vapor transition, is substantially isolated from interfering absorption of other species of said plurality of species.
Dependencies are inferred from the claim text.