A Chromatographic Method for Determination of Trace Impurities in Grade-A Helium.

Simple Technique for the Ultrapurification of Helium

“…2 /g) at random temperatures ranging from approximately 30° to 175 OK. For these experiments, a charcoal trap was suspended at varying heights above boiling liquid helium or nitrogen in a conventional glass dewar. The composition of the effluent gas from the trap was checked periodically on a modified gas chromatograph with a detectable limit for neon of 0.2 ppm [2]. From these runs it was determined that charcoal should be kept below 50 0 K to ensure removal of all impurities from a large volume of Grade-A helium.…”

“…Trace-impurity analyses of regasified liquid helium produced by an ADL-Collins helium liquefier [1] were made by a chromatographic method described in the literature [2]. The results indicated a helium of the desired purity (at least 99.9999 mol.…”