Patent ID: 6768108
Filing Date: 2004-07-27
Classification: H01J

Abstract:
An ion attachment mass spectrometry apparatus, comprising:a first chamber and a second chamber; a partition separating the first chamber and the second chamber, the partition having an aperture; a sample gas introduction mechanism for introducing a sample gas having molecules into the first chamber; an emitter for generating positive metal ions to attach to the molecules of said sample gas to obtain positive ions; a mass spectrometer for analyzing a mass of said sample gas attached with said metal ions; a vacuum pump for reducing the pressure of at least said second chamber; and a controller for controlling the apparatus so that a supersonic jet region is formed in said second chamber by making the Knudsen number &lgr;/D (where &lgr; is length of mean free path of the gas in the first chamber and D is the diameter of said aperture) of said aperture not more than 0.01, for making the pressure of said second chamber not more than {fraction (1/10)}th of that of said first chamber, for making the gas of said sample of said first chamber be blown out from said aperture to said second chamber, and for injecting the gas of said sample gas and said metal ions into said supersonic jet region to make said metal ions attach to the molecules of said sample gas at said supersonic jet region.