Patent ID: 9230788
Filing Date: 2016-01-05
CPC Classification: H01J

Claim Text:
1. A mass spectrometer comprising an ion guide in which 2n (where n is an integer equal to or larger than 3) rod-like or plate-like electrodes extending along an ion optical axis are arranged so as to surround the ion optical axis, the mass spectrometer further comprising: a) voltage generating means for generating a first radio-frequency voltage and a second radio-frequency voltage having a same amplitude as and an inverted phase from the first radio-frequency voltage, as voltages for forming a radio-frequency electric field in a space surrounded by the respective electrodes of the ion guide; and b) electrical connecting means for electrically connecting the voltage generating means and the respective electrodes of the ion guide such that the first radio-frequency voltage is applied to m (where m is an integer equal to or larger than 2 and equal to or less than 2n−1) electrodes adjacent to each other around the ion optical axis among the 2n electrodes constituting the ion guide, and the second radio-frequency voltage is applied to at least one of the other 2n−m electrodes; the arrangement of the respective electrodes being rotationally symmetrical about the ion optical axis.