Carbon isotope analysis device and carbon isotope analysis method

A carbon isotope analysis device comprising:

• a carbon dioxide isotope generator provided with a combustion unit that generates gas containing carbon dioxide isotope from carbon isotope, and a carbon dioxide isotope purifying unit, the carbon dioxide isotope purifying unit comprising a gaseous contaminant separating unit, a concentrating unit of the carbon dioxide isotope, and a dehumidifying unit;
• a spectrometer comprising an optical resonator having a pair of mirrors and a cooler for prevention of noise generation, and a photodetector that determines intensity of light transmitted from the optical resonator;
• a carbon dioxide trap comprising a cooler for freezing the carbon dioxide isotope, the carbon dioxide trap being disposed between the carbon dioxide isotope generator and the spectrometer;
• and
• a light generator.

A carbon isotope analysis method, comprising the steps of:

• generating carbon dioxide isotope from carbon isotope;
• cooling a carbon dioxide trap to 0° C. or less;
• sending the carbon dioxide isotope and gas containing carrier gas lower in freezing point than the carbon dioxide isotope, into the carbon dioxide trap, thereby condensing the carbon dioxide isotope;
• removing gas in the carbon dioxide trap;
• heating the carbon dioxide trap with the carbon dioxide trap being shielded from the outside, thereby gasifying the condensed carbon dioxide isotope;
• filling an optical resonator with the gasified carbon dioxide isotope;
• generating a mid-infrared optical frequency comb of a wavelength range from 4.5 μm to 4.8 μm, as irradiation light at an absorption wavelength of the carbon dioxide isotope;
• measuring the intensity of the transmitted light generated by resonance of the carbon dioxide isotope excited by the irradiation light;
• and
• calculating the concentration of the carbon isotope from the intensity of the transmitted light.