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Title: Self-tuning method for monitoring the density of a gas vapor component using a tunable laser

The present invention relates to a vapor density monitor and laser atomic absorption spectroscopy method for highly accurate, continuous monitoring of vapor densities, composition, flow velocity, internal and kinetic temperatures and constituent distributions. The vapor density monitor employs a diode laser, preferably of an external cavity design. By using a diode laser, the vapor density monitor is significantly less expensive and more reliable than prior art vapor density monitoring devices. In addition, the compact size of diode lasers enables the vapor density monitor to be portable. According to the method of the present invention, the density of a component of a gas vapor is calculated by tuning the diode laser to a frequency at which the amount of light absorbed by the component is at a minimum or a maximum within about 50 MHz of that frequency. Laser light from the diode laser is then transmitted at the determined frequency across a predetermined pathlength of the gas vapor. By comparing the amount of light transmitted by the diode laser to the amount of light transmitted after the laser light passes through the gas vapor, the density of the component can be determined using Beer`s law. 6 figs.
Inventors:
; ; ;
Issue Date:
OSTI Identifier:
372579
Assignee:
Dept. of Energy, Washington, DC (United States) PTO; SCA: 400800; PA: EDB-96:144539; SN: 96001644969
Patent Number(s):
US 5,550,636/A/
Application Number:
PAN: 8-425,681
Contract Number:
W-7405-ENG-48
Resource Relation:
Other Information: PBD: 27 Aug 1996
Research Org:
University of California
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; VAPORS; MONITORING; DENSITY; MONITORS; DESIGN; SEMICONDUCTOR LASERS