A new method to measure the concentration of argon-xenon gas mixture

Background RGAs are widely used in molecular component examination, impurity analysis, leak detection and test of vacuum system performance. However, RGAs have different sensitivities to different gases, and the sensitivities can change quickly and depend on so many parameters, which make its ability severely limited.
Methods In this work we established a new practical method to precisely measure noble gas ratio of argon -xenon gas mixture. Gaseous argon and xenon were controlled, respectively, by two mass flow controller (MFC). A variable leak valve (VLV) was used to introduce the gas mixture sample into the RGA measurement chamber. Gas mixtures with xenon concentration from 200ppm to 20000ppm (by mass) were introduced and tested by RGA.
Results The time stability of RGA-measurement system was optimized to 2.1%. A good linearity of MFC-RGA response was achieved, verifying the reliability of RGA in measuring noble gas mixture with component concentration down to several hundred ppm level.
Conclusions Since the approach we used in our experiment is gas-species independent, we believe that it can be popularized to other gas species when properly applied.