scope:

Specifies terms and procedures for the characterization of mass spectrometer leak detectors (MSLD). It is not intended to give a complete set of specifications for an acceptance test but a description of procedures that can be used without particular calibration equipment. An MSLD has an integral high vacuum system for maintaining the sensing element (mass spectrometer) at low operating pressure and for establishing a partial pressure related to the incoming gas flow. This pressure is measured quantitatively by the mass spectrometer. Such instruments are able to selectively measure the flow of a tracer gas. In most cases the tracer gas will be helium, flowing in/out of an object through a leak.