Highly Accurate Measurements of Xenon Stable Isotope Abundance on Static Gas Mass Spectrometer

Abstract

A high accuracy method for Xenon isotope abundance measurements was developed on a Helix MC Plus static gas mass spectrometer，in order to solve the problem that the mass difference of the nine stable isotopes of Xe is large (about 9.6%) and the mass spectrometry detector is difficult to accept, for get the abundance of all the stable isotopes of Xe quickly and accurately. The gas sample containing Xenon was purified and separated before introduced into the mass spectrometer analyzing chamber firstly, which helps reducing the influence on Xenon isotopic measurement brought by other noble gases and active components. Then, a measurement method combining peak hopping and multi reception was used to achieve high precision measurement of all stable isotopes of Xe at extremely small sample amount based on the Helix MC Plus static gas mass spectrometer. The measured data were corrected by referring to the Xenon isotopic reference gas finally. Results show that, under the condition of small sample amount (approximately 1.12×10-12 mol), the relative standard deviation (RSD) of the measured 129Xe/132Xe, 130Xe/132Xe, 131Xe/132Xe, 134Xe/132Xe, 136Xe/132Xe were within 0.24% by Faraday, and 124Xe/132Xe, 126Xe/132Xe were within 0.22% and 0.39% by counting method separately. This method achieves abundance ratio analysis of trace Xe stable isotopes with good stability and high accuracy.

Keywords

• xenon isotope
• static mass spectrometer
• abundance measurements
• separation and purification