Optical oxygen concentration monitor

Patent · Wed Jan 01 00:00:00 EST 1997

OSTI ID:871064

Kebabian, Paul ^[1]

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1. Acton, MA

A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen's A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest.

• Research Organization: Aerodyne Research, Inc., Billerica, MA (United States)
• DOE Contract Number: FG02-93ER81522
• Assignee: Aerodyne Research (Billerica, MA)
• Patent Number(s): US 5650845
• OSTI ID: 871064
• Country of Publication: United States
• Language: English

Related Subjects

optical
oxygen
concentration
monitor
measuring
monitoring
light
source
argon
discharge
lamp
inherently
emits
spectral
line
close
a-band
absorption
lines
preferred
embodiment
split
sets
components
shorter
wavelengths
magnetic
field
approximately
2000
gauss
parallel
propagation
wavelength
centered
readily
absorbed
moved
minimally
polarization
modulator
alternately
selects
set
upshifted
downshifted
passes
selected
environment
transmission
path
transmitted
flux
varies
result
differential
determines
based
changes
alternative
embodiments
modulation
achieved
selectively
reversing
polarity
supplying
emitting
plasma
emits light
differential absorption
alternative embodiments
selectively supplying
spectral line
oxygen concentration
discharge lamp
light source
magnetic field
preferred embodiment
alternative embodiment
shorter wavelength
absorption line
transmitted optical
concentration monitor
light propagation
line varies
inherently emits
polarization modulator
argon discharge
/356/250/