THE USE OF A HELIUM MASS SPECTROMETER LEAK DETECTOR

摘要

This document describes some fundamental theoretical and practical applications of the helium mass spectrometer leak detector in relation to vacuum chambers and particularly to items to be leak checked inside vacuum chambers. Of the three basic methods of leak detection-pressure testing, vacuum testing, and pressure-vacuum testing—only the latter is treated extensively. The leak detector output is derived as a function of the pressure of the helium or helium mixture behind the leak, as a function of helium concentration, and as a function of time. The results are discussed both quantitatively and qualitatively.