电子倍增器歧视效应和质量分馏效应的修正及其应用

The Corrections for Mass Fractionation and Electron Multiplier Discrimination

文章介绍了电子倍增器测量引入的质量相关偏差和离子束流强度相关偏差的修正方法,给出了正确的计算公式;叙述了用同位素比值对关系线归一法修正样品蒸发和电离引入的质量分馏效应的方法,给出了计算分馏效应修正因子和计算修正值的公式。用上述方法分别对天然镁和天然锗样品的同位素丰度比值或同位素丰度进行修正后,天然镁同位素的丰度比值为:^(26)Mg/^(24)Mg=0.13938,^(25)Mg/^(24)Mg=0.12660;天然锗的同位素丰度为:^(70)Ge=20.50,^(72)Ge=27.48,^(73)Ge=7.76,^(74)Ge=36.51,和^(76)Ge=7.75。天然样品的分析结果与文献标定值相符。

The measured accuracy of magnesium and germanium isotope ratios by electron multiplier is limited by biases related to the differences in mass and intensity of the ion beams being measured. The accuracy is also subjected to the error resource from mass fractionation. The methods and general equations corrected for the biases in the isotopic ratios measured by electron multiplier were given in this paper. The methods and equations corrected for the mass fractionation by normalizind method based on the correlative line between isotopic ratio and ratio were also described. Finally. the results obtained from nature-magnesium isotopic ratios and nature-germanium abundances are ^(26)Mg/^(24)Mg=0.13938, ^(25)Mg/^(24)Mg=0.12660; ^(70)Ge=20.50, ^(72)Ge=27.48, ^(73)Ge=7.76, ^(74)Ge=36.51, and ^(76)Ge=7.75, respectively.