Bandpass mass filter

Abstract

A bandpass mass filter comprising: a multipole ion guide; a first RF voltage supply configured to apply a first RF voltage to electrodes of the multipole ion guide for generating an electric field for radially confining ions within the multipole ion guide; and a second RF voltage supply configured to apply a second, different RF voltage to electrodes of the bandpass mass filter, wherein a first phase of the second RF voltage is applied to a first pair of opposing electrodes and a second, different phase of the second RF voltage is applied to a second pair of opposing electrodes; wherein the frequency of the second RF voltage is at least 20 times lower than the frequency of the first RF voltage; and wherein the bandpass mass filter is configured to be maintained at a pressure of ≥10−4 mbar.

Dependencies are inferred from the claim text.