researcherA new method based on tunable infrared laser direct absorption spectroscopy has been proposed，Used for precise measurement of double in methanereplace同Voxel body13CH3DAnd use it for methane isotope thermometer research. MakeuseTILDASInstrument equipped with two continuous wave quantum cascade lasers（QCLs）A laser is tuned to8.6 μm, used for measurement13CH3DThe12CH3Dand12CH4；Another laser is tuned to7.5 μm，for measuring13CH4，choice8.6 μmBand（ν4Avoid specific absorption lines from major isotopes (such as12CH4）The interference，利用HITRANdatabase（High resolution transmission molecular absorption databaseRecord specific information on the absorption of light in different spectral bands of various important molecules in the atmosphereDetermine absorption line parameters，Ensure low interference and low temperature dependence.adoptVoigtlinear（Considering both temperature and pressure effects comprehensively，Optimize the matching of experimentally measured spectral curves）Perform least squares spectral fitting and calculate the number density of each isotope body，By using the equilibrium constantK(T)andΔ13CH3Ddefinition，correlation13CH3DAbundance andFormation temperature.

This method is effective for10 mL STP(Standard temperature and pressure)methanesampleΔ13CH3DThe measurement accuracy reaches0.2‰（2s）Accuracy0.7‰（2s）, small sample（0.5 mL STP）Measurable, but with low accuracy（±0.6‰），Uncertainty in temperature estimation:±7°C（25°CWhen) and±20°C（200°CAt that time,Commercial high-purity methane andMITNatural gas samplesΔ13CH3DValue corresponds to apparent temperature151–212°C, with thermogenic methane“Gas Window”agreement,proofTILDASCan distinguish between biogenic sources and heat sources of methanecausesource.

the aboveunder studyThe equipment used isTILDASdual lasermethaneCluster isotopemeasurement systemIts core consists of two separately tuned to8.6 μmand7.5 μmContinuous wave quantum cascade laser in the wavelength range, with an effective optical path length of up to76Mi's astigmatic multi-channel Herriot absorption cell, as well as a highly stable temperature control and static injection system. This device precisely controls the sample pressure and temperature, and performs absorption lines on specific wavelengths of methane isotopesVoigtLinear spectral fitting，Realized the identification of highly low abundance dual substituted methane isotopes13CH3DNon destructive, high-precision direct measurement.

fromAustralian worksThe company's agentAerodynemethaneCluster Isotope Measurement SystemFast and high-precision measurementmethaneCluster isotope.The technology of this productadvantageAs follows:

Ø avoidSame quantitydifferentVoxel interference：TILDASTechnology detects the unique infrared vibrational spectra of molecules rather thanmass-to-charge ratioFundamentally avoiding the interference of isoquanta in mass spectrometry. Through precise selection¹³CH ₃DExclusive absorption line and measurement，It can directly and selectively obtain its concentration information without worrying about other ions with the same mass number (such as...)¹²CH ₂D₂⁺Or added ions)Causing interference.

Ø high-precision measurement：60minMeasurement time and5mlThe standard sample has better accuracy than0.2‰（1s）, comparable toIRMS，while maintaininghigh precisionUnder the premise,methaneCluster isotope measurement system requires less sample size and faster analysis speed，High resolution traceability of trace precious samples has been achieved，Improved the constraint capability of methane source apportionment model，More accurate assessment of the proportion of biogenic, thermogenic, and abiotic sources, thereby achieving greater precisionaccountingcarbonflux.