Aperture gas flow restriction

摘要

A mass spectrometer is disclosed comprising two vacuum chambers maintained at different pressures. The two vacuum chambers are interconnected by a differential pumping aperture. The effective area of the opening between the two vacuum chambers may be varied by rotating a disk having an aperture in front of the differential pumping aperture so as to vary the gas flow rate through the opening and between the two chambers.

主权项

1. A mass spectrometer comprising:
two chambers to be maintained at different pressures in use, wherein both of said chambers comprise a vacuum chamber and are connected to a vacuum pump for maintaining the chambers at said different pressures, wherein the two chambers are interconnected by an opening for transmitting ions from one of the chambers to the other of the chambers; a first device for varying an area of the opening so as to vary a gas flow rate through the opening and between the chambers in use, wherein the area of the opening can be varied from a relatively large area to a relatively small area or from the relatively small area to the relatively large area wherein a high gas flow rate is permitted between the chambers when the area of the opening is of the relatively large area and a low gas flow rate is permitted between the chambers when the area is of the relatively small area; and an ion storage device for pulsing ions towards and through said opening, said ion storage device being synchronised with the opening such that ions are pulsed through the opening when the opening is of the relatively large area and ions are accumulated within the ion storage device and not pulsed through the opening when the opening is of the relatively small area or is closed.