1. Description of a purification cabinet

1.1 Requirements

The chambers in which noble gas purification takes place are designed to reduce the sources of external contamination (degassing, permeation, backscattering, etc.) that can affect the accuracy of isotope ratio measurements and/or elemental fractionation analysis. In fact, there are many species, most often organic, which interfere with noble gases in a non-resolved way during mass spectrometry measurements, and whose impact must be minimized. It is therefore advisable to design purification chambers entirely in stainless steel, as this material has the advantage of being non-porous, even with helium, and of offering extremely low outgassing rates, compatible with ultra-high vacuum. The enclosure, initially at atmospheric pressure during assembly, must be designed to...