Apparatus for control of gas flow into a mass spectrometer using a series of small orifices

摘要

A gas sampling and inlet device for a mass spectrometer has a hollow housing sleeve with an open inside region and a hollow inner sleeve with an open inside region, with the inner sleeve coaxial to the housing sleeve. One end of the housing sleeve and one end of the inner sleeve are connected with a single first end cap. The second end of the housing sleeve has a second end cap, but the second end of the inner sleeve is open such that the inside of the inner sleeve is open to the inside of the housing sleeve. The first end cap has a small diameter orifice adapted to receive a gaseous fluid. The second end cap is connected to a mass spectrometer. The second end cap has an orifice adapted to receive a gaseous fluid into the mass spectrometer that is substantially smaller in diameter than the orifice in the first end cap. The housing sleeve has a vacuum pump port to allow a vacuum to be created in the interior of the inlet device.