|국가/구분||United States(US) Patent 등록|
|미국특허분류(USC)||356/440 ; 356/437|
|발명자 / 주소|
|출원인 / 주소|
|대리인 / 주소||
|인용정보||피인용 횟수 : 61 인용 특허 : 42|
A method and apparatus for in situ measurement of the concentration of a gas with a frequency modulated tunable diode laser is disclosed. The sampling cell, which is mounted in the flow of gases to be measured, is a Herriott cell. Gas enters the sampling cell through sintered metal filters that prevent entrance of particulates. Signals from a sample detector and a null detector are compared to eliminate interference patterns from the laser optics. High accuracy dynamic calibration of the apparatus is also disclosed.
[ What is claimed is:] [1.] Apparatus for measuring concentration of a gas comprising:a tunable diode laser, said laser being tuned to project a laser beam at the wavelength of a spectral feature of said gas, said laser beam being modulated;a sampling cavity having a first end and a second end, said first and second ends having opposed interior reflecting surfaces;a lens attached to said first end, said laser beam being projected onto said lens, said lens splitting said laser beam, deflecting a first surface reflection of said laser beam and projecting s...