快速测量Xe稳定同位素丰度及其质量歧视校正

Rapid Measurement of Xe Stable Isotope Abundance and Mass Discrimination Correction

为准确测量Xe同位素丰度,本研究针对Xe同位素电离后各离子在磁场中的运动特征设定了MAT253型质谱计法拉第杯的位置,并用其快速测量了天然Xe的9种同位素丰度。MAT253作为一种磁质谱计,为解决测量同位素丰度时的质量歧视效应问题,采用内标法,利用幂函数、指数和平衡校正规律对Xe同位素丰度的质量歧视进行校正。测量结果的相对标准偏差≤0.13%,而以131 Xe/132 Xe做为内标的幂校正方法,得到的Xe同位素丰度更接近于参考值。校正后各同位素与参考值的偏差均≤1.46%,且各同位素的标准不确定度均≤0.21%(k=2)。

In this study,the position of Faraday Cup of MAT253 mass spectrometer was set according to the motion characteristics of ions in magnetic field after Xe isotope ionization,and the abundance of nine Xe isotopes were measured,in order to accurately measure the Xe isotopic abundance.As a magnetic mass spectrometer,MAT253 has mass discrimination effect when measuring isotope abundance.To address this issue,the internal standard method was used to correct the mass discrimination of Xe isotope abundance values by using power function,exponential function and equilibrium correction law.The relative standard deviation of measurement results was less than or equal to 0.13%,and the Xe isotope abundances obtained by the power fuction correction with 131 Xe/132 Xe as internal standard were closer to the natural values.The corrected deviation of each isotope from the reference values were within 1.46%,and the standard uncertainty of each isotope was within 0.21%(k=2).