SYSTEM AND METHOD FOR APPLYING CURTAIN GAS FLOW IN A MASS SPECTROMETER

摘要

A system of mass spectrometry is disclosed having an ion source for generating ions at substantially atmospheric pressure. The system has a sampling member with an orifice disposed therein. The sampling member forms a vacuum chamber with a mass spectrometer. The system also has a curtain plate between the ion source and the sampling member. The curtain plate has an aperture therein, having a cross-section and being spaced from the sampling member to define a flow passage between the curtain plate and the sampling member, and to define an annular gap between the orifice and the aperture. The area of the annular gap is less than the cross-sectional area of the aperture. The system also has a power supply for applying a voltage to the curtain plate, and a curtain gas flow mechanism for directing a curtain gas into the flow passage and the annular gap.