Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
  • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers

Definitions

• the present invention relates to a method and an apparatus for isotopomer absorption spectroscopy, and particularly to laser spectroscopy.
• FIG. 1 is a schematic view of a conventional isotopomer absorption spectrometer.
• 1 is a semiconductor laser
• 2 is a Peltier device
• 3 is a laser controller
• 4 is a current controller
• 5 and 9 are reflection mirrors
• 24 is a measurement gas cell
• 25 is a measurement gas cell
• 26 is a set of reflecting mirrors
• 25 A is a hole formed in the reflecting mirror
• 21 is a beam splitter
• 22 is a gas cell for stabilizing wavelength
• 10 and 23 are photoelectric conversion elements
• 1 test sample e.g., unknown presence ratio of H 2 16 ⁇ and H 2 18 0
• 32 standard samples e.g., abundance ratio of H 2 16 0 and H 2 18 0 is known
• 33, 34 and 35 are opening / closing control valves.
• conventional absorption spectroscopy analyzers use a long optical path cell as the measurement gas cell 24 to increase the level of the absorption signal for measurement in order to measure a substance having a relatively low concentration, and to use an absorption line.
• a wavelength stabilizing gas cell 22 containing a high-purity measurement substance was used.
• the conventional absorption spectrometer measures a substance with a relatively high concentration in order to make the absorption signal level comparable when the concentration difference between the substances to be measured is large. To do so, the optical path length was relatively short. As a result, there is no problem if the optical path length can be shortened. However, as in the case of isotopomer analysis of water vapor, there is no difference between the semiconductor laser 1 and the measurement gas cell 24 or between the measurement gas cell 24 and the photoelectric conversion element 10. In order to perform measurement using an absorption line with a large absorption coefficient because the water vapor existing between the cells affects the measurement, the optical path excluding the measurement gas cell 24 is placed in a container, and the inside of the container is replaced with a dry gas (air or nitrogen). Or a vacuum inside the container.
• a dry gas air or nitrogen
• the output of this photoelectric conversion element is photoelectrically converted.
• the number of optical elements such as a beam splitter and a photoelectric conversion element should be reduced as much as possible.
• the present invention has been made in view of the above circumstances, and provides an isotopomer absorption spectroscopy method and apparatus capable of accurately measuring the isotope ratio with a simple configuration even when the concentration difference between the measurement substances is large. Aim.
• the combination of absorption lines used for laser absorption spectroscopy is so low that the absorption signal levels of a plurality of substances with very different concentrations existing in the same measurement gas cell are made equal.
• Analysis of isotopomers which are molecular species containing isotopes in their molecules, can be performed by selecting a smaller absorption coefficient of the analyte at a higher concentration than the analyte at a lower concentration than at the analyte at a lower concentration. Is performed.
• the absorption coefficient of the high concentration of the measurement substance is selected smaller than that of the low concentration of the measurement substance.
• a wavelength stabilizing / measuring gas cell that serves both as a gas cell and a measuring gas cell is provided.
• the wavelength stabilization gas cell and the measurement gas cell used for control may be used. This is because the controllability of wavelength stabilization is not different from the case where a gas cell for wavelength stabilization is separately provided, since the concentration fluctuation is small at a high concentration.
• FIG. 1 is a schematic diagram of a conventional isotopomer-absorption spectrometer.
• FIG. 2 is a schematic view of an isotoboma-absorption spectrometer showing an embodiment of the present invention.
• FIG. 2 is a schematic view of an isotopomer absorption spectroscopy analyzer showing an embodiment of the present invention.
• 6 is a wavelength stabilizing and measuring gas cell
• 7 and 8 are a set of reflecting mirrors
• 7A is a hole formed in the reflecting mirror 7, and the other parts are shown in FIG. It is the same as the one above, and their explanation is omitted.
• the wavelength stabilizing and measuring gas cell 6 is arranged such that the wavelength stabilizing gas cell 22 and the measuring gas cell 24 used for the control shown in FIG. 1 are also used. . This is because the controllability of the wavelength stabilization is different from the case where the wavelength stabilization cell 22 is provided separately because the concentration fluctuation is small at a high concentration. Because there is no.
• the conventional isotopomer absorption spectrometer required the video that was necessary.
• the absorption signal level can be made comparable for different isotope species, and the isotope abundance ratio Can be accurately measured.
• the present invention by using a gas cell for wavelength stabilization and a gas cell for measurement, it is not necessary to use a cell equivalent to a long optical path cell required for measurement, and the effect is remarkable.
• the isotopomer absorption spectroscopy has been described.
• the present invention can be widely applied to spectroscopy of gas having a concentration difference.
• it can be applied to laser spectroscopy when a high-purity gas contains a trace amount of impurity gas.
• the present invention is not limited to the above embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention. As described above, according to the present invention, the following effects can be obtained.
• the absorption signal levels of multiple substances with significantly different concentrations existing in the same measurement gas cell are made uniform to the same level, and Analysis of isotopomer, a molecular species containing.
• the absorption coefficient of the high-concentration test substance compared to the low-concentration test substance is selected to be smaller than that of the low-concentration test substance so as to obtain the same level, and wavelength stabilization control in the measurement is selected.
• Cell for wavelength stabilization and measurement A gas cell can also be used.
• isotopomer-absorption spectroscopy analysis quantitative analysis is performed by precisely measuring isotopomers, which are molecular species containing isotopes in the molecule, to estimate the origin and history of the molecule. It can be applied to environmental measurement, science, and medical fields for diagnostic purposes.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Analytical Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Optics & Photonics (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Optical Measuring Cells (AREA)

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• 2000
  • 2000-08-31 JP JP2000263086A patent/JP2002071557A/ja active Pending
• 2001
  • 2001-06-05 AU AU2001262694A patent/AU2001262694A1/en not_active Abandoned
  • 2001-06-05 WO PCT/JP2001/004736 patent/WO2002018918A1/ja active Application Filing

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