High Sensitivity Mass Spectrometer for Noble Gas Analysis

Abstract

A high-sensitivity mass spectrometer for noble gas analysis is described in detail. Ultra-high vacuum techniques have been used throughout so that small rare gas samples can be closed off within the spectrometer envelope and analyzed statically. This procedure is of considerable advantage in analyzing argon and lighter rare gases. The background spectrum when the spectrometer pressure is 5×1010 mm Hg is described. Sensitivity data are presented. The detectability of the instrument for xenon atoms (any isotope) is 0.5×106 atoms; for A36, the detectability is 14×106 atoms.