Title:
GAS MEASURING INSTRUMENT AND ISOTOPIC CONCENTRATION RATIO MEASURING INSTRUMENT
Document Type and Number:
Japanese Patent JP3304846
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To perform the measurement of isotopic concentration ratios with high sensitivity by utilizing the absorption of laser beams.
SOLUTION: In order to measure the isotopic concentration ratio between 12CO2 and 13CO2, a laser device 10 utilizing 13CO2 and another laser device 12 utilizing 12CO2 are used. The laser beams from the devices 10 and 12 are introduced to an external resonator 20 filled up with a sample gas (the breath of a patient after the patient is does with a reagent) and another external resonator filled up with a reference gas (a normal CO2 gas or the breath of the patient before the patient is dosed with the reagent). The difference between the isotopic concentration ratio of the reference gas and that of the sample gas is observed at the output level of a differential amplifier. In the resonators 20 and 22, the absorption of the laser beams caused by the gases can be detected with high sensitivity by utilizing the resonance of the laser beams.
Inventors:
Yoshio Zhang
Tomofumi Matsushima
Hosomi Shohei
Hiroshi Maekawa
Junichi Kawanabe
Tomofumi Matsushima
Hosomi Shohei
Hiroshi Maekawa
Junichi Kawanabe
Application Number:
JP25046997A
Publication Date:
July 22, 2002
Filing Date:
September 16, 1997
Export Citation:
Assignee:
Aloka Co., Ltd.
International Classes:
G01N33/497; G01N21/35; G01N21/3504; (IPC1-7): G01N21/35; G01N33/497
Domestic Patent References:
| JP8261922A | ||||
| JP7270308A | ||||
| JP1194737A | ||||
| JP1194738A | ||||
| JP1194739A | ||||
| JP1194740A | ||||
| JP7294418A | ||||
| JP52114390A | ||||
| JP52100276A | ||||
| JP5298578A |
Attorney, Agent or Firm:
Kenji Yoshida (2 outside)