Vacuum system for a mass spectrometer

Abstract

A mass and/or ion mobility spectrometer comprising: an ion source enclosure; a first vacuum chamber in fluid communication with said ion source enclosure via a first orifice; an isolation valve for at least partially closing said first orifice; a first pump for evacuating the ion source enclosure when the isolation valve is closed; and control circuitry configured to operate the spectrometer in a first mode in which the first pump evacuates the ion source enclosure through a conduit having a gas passage therethrough that is relatively restricted, and to then subsequently operate in a second mode in which the first pump evacuates the ion source enclosure through a conduit having a gas passage therethrough that is less restricted.

Dependencies are inferred from the claim text.