CPC H01J 49/067 (2013.01) [H01J 49/0031 (2013.01); H01J 49/4225 (2013.01); H01J 49/426 (2013.01)] | 23 Claims |
1. Apparatus for reducing contamination in a mass spectrometer comprising:
an ionization chamber for generating a beam of ions;
an ion guide having a plurality of rods arranged in a multipole configuration and spaced from one another to provide a channel through which an ion stream comprising ions generated in the ionization chamber can be transmitted to one or more downstream mass analyzers, the ion guide channel comprising a guide inlet aperture in communication with said ionization chamber and a guide exit aperture for passing ions to said downstream mass analyzers,
a power supply for providing voltage to one or more of said plurality of rods for confining the ions within an internal volume of the ion guide channel;
a curtain gas inlet for introducing an internal curtain gas into the ion guide channel at a volumetric flow rate of at least 0.1 standard liter per minute (slpm) flowing in a contra flow direction to the ion stream, such that the internal curtain gas flow facilitates removal of neutral molecules from the ion stream.
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