SAMPLE GAS CONTROL FOR ION-TRAP MASS SPECTROMETER USED IN CHEMICAL IONIZATION MODE

摘要

PURPOSE: To provide a gas flow control system for feeding a sample gas to an ion-trap mass spectrometer, with an ability to make the sample gas flow and stop it, without generating pressure surge in an ion trap. ;CONSTITUTION: A sample gas flow control system is used, along with an ion-trap mass spectrometer. The sample gas flows through a first gas flow restrictor 70 from a gas source 5. The first gas flow restrictor 70 is connected to second and third gas flow restrictors 80, 90. The second restrictor 80 is connected to an ion trap 10, where the sample gas is used, and output of the third restrictor 90 is connected to a vacuum pump which may be a roughing vacuum pump 20 used by the ion trap. At least one of three restrictors is a variable restrictor. A simple, inexpensive element can therefore be used for accurate flow control.;COPYRIGHT: (C)1994,JPO