Optical monitor for water vapor concentration
Abstract
A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field ormore »
- Inventors:
-
- Acton, MA
- Issue Date:
- Research Org.:
- Aerodyne Research, Inc. (Billerica, MA)
- OSTI Identifier:
- 871600
- Patent Number(s):
- 5760895
- Assignee:
- Aerodyne Research, Inc. (Billerica, MA)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- DOE Contract Number:
- FG02-95ER81915
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- optical; monitor; water; vapor; concentration; measuring; monitoring; sample; light; source; argon; discharge; lamp; inherently; emits; spectral; line; close; absorption; preferred; embodiment; split; magnetic; field; parallel; direction; propagation; sets; components; downshifted; upshifted; frequencies; approximately; 1575; gauss; centered; readily; absorbed; moved; minimally; polarization; modulator; alternately; selects; passes; selected; transmission; transmitted; intensity; component; varies; result; determines; based; differences; alternative; embodiments; alternate; selection; achieved; selectively; reversing; polarity; supplying; emitting; plasma; emits light; alternative embodiments; selectively supplying; spectral line; discharge lamp; water vapor; light source; magnetic field; preferred embodiment; alternative embodiment; transmitted intensity; absorption line; vapor concentration; optical monitor; selected components; monitoring water; light propagation; line varies; inherently emits; selected component; polarization modulator; argon discharge; /356/250/
Citation Formats
Kebabian, Paul. Optical monitor for water vapor concentration. United States: N. p., 1998.
Web.
Kebabian, Paul. Optical monitor for water vapor concentration. United States.
Kebabian, Paul. Thu .
"Optical monitor for water vapor concentration". United States. https://www.osti.gov/servlets/purl/871600.
@article{osti_871600,
title = {Optical monitor for water vapor concentration},
author = {Kebabian, Paul},
abstractNote = {A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1998},
month = {Thu Jan 01 00:00:00 EST 1998}
}