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公开(公告)号：EP0977028A4
公开(公告)日：2001-05-23
申请号：EP99901876
申请日：1999-01-27
申请人： NIPPON OXYGEN CO LTD
发明人： WU SHANG-QIAN , MORISHITA JUN-ICHI
CPC分类号： G01N21/39 , G01N2021/391
摘要： An absorption spectrochemical analysis using frequency-modulated laser produced by a semiconductor laser device. To measure absorption spectra, the semiconductor laser device is operated by injection current in a range between the lower limit (B) where the change in laser intensity as the increase in injection current becomes close to a minimum and the higher limit (C) where the change in laser wavelength as the increase in injection current becomes close to a minimum. This method allows minute impurity in gas to be measured with high sensitivity and accuracy.
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公开(公告)号：EP0706042A4
公开(公告)日：1998-11-04
申请号：EP95913317
申请日：1995-03-22
申请人： NIPPON OXYGEN CO LTD
CPC分类号： G01N21/39 , G01J3/433 , G01N21/3504 , G01N21/3554 , G01N2021/399
摘要： A method and apparatus for measuring the concentration of a very small amount of impurities in an object gas by an infrared spectroscopic analysis using a semiconductor laser. In order to carry out the analysis with a high sensitivity and a high accuracy, an object gas is introduced into a sample cell (5) and the cell is evacuated by a vacuum pump (16). An infrared beam of a wavelength in a region in which a high absorption peak due to impurities appears is emitted from a semiconductor laser (1) and passed through the sample cell (5) and a reference sample cell (8) in which impurities alone are sealed to measure a differential value absorption spectrum. The impurities are identified by comparing the spectrum of the object gas with that of impurities alone and determining a plurality of absorption peaks concerning the impurities, and the quantity of the impurities is determined on the basis of the absorption intensity at the highest peak. When impurity gas molecules form clusters in the object gas, the light of not less than 0.5 eV is applied to the clusters to dissociate the same, and the analysis of the gas is then carried out. This invention is suitably utilized, especially, for analyzing a very small amount of impurities in a semiconductor material gas.
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