ASTM E 493 - 97. Standard Test Methods for Leaks Using the Mass Spectrometer Leak Detector in the Inside-Out Testing Mode

American Society for Testing and Materials (ASTM). 1997, 3 pages.
These test methods cover procedures for testing devices that are sealed prior to testing, such as semiconductors, hermetically enclosed relays, pyrotechnic devices, etc., for leakage through the walls of the enclosure. They may be used with various degrees of sensitivity (depending on the internal volume, the strength of the enclosure, the time available for preparation of test, and on the sorption characteristics of the enclosure material for helium). In general practice the sensitivity
limits are from 4.4 3 10−15 to 4.4 3 10−11 moles/s (10−9standard cm3/s to 10−5 standard cm3/s at 0°C) for helium, although these limits may be exceeded by several decades in
either direction in some circumstances