Patent ID: 8563925

Claim:
A mass spectroscope comprising: a sample introduction chamber for introducing therein a sample; an ionization chamber for ionizing the sample which has been introduced into the sample introduction chamber; an ion trap section for separating the sample ionized in the ionization chamber according to the mass of the ions; a detector for detecting ions having predetermined mass among the ions separated in the ion trap section; and a data processing unit for processing data obtained as the result of detecting the ions by the detector, wherein: the ion trap section includes: a rod electrode section having two pairs of rod electrodes (four rod electrodes in total), each pair of rod electrodes being disposed in such a manner that the rod electrodes of the pair face each other; an RF signal source for generating an RF signal; a resonance circuit unit for resonating and amplifying the RF signal generated by the RF signal source to generate a high-voltage RF signal, applying the high-voltage RF signal to one of the two rod electrode pairs, and applying the high-voltage RF signal, the phase of which is reversed from that of the high-voltage RF signal applied to the one of the two rod electrode pairs, to the other of the two rod electrode pairs, the rod electrodes of each rod electrode pair facing each other with respect to the central axis of the four rod electrodes of the rod electrode section; a resonance frequency/amplitude difference measuring unit for measuring an amplitude difference between the high-voltage RF signal applied to the one of the two rod electrode pairs and the reversed-phase high-voltage RF signal applied to the other of the two rod electrode pairs, and measuring a resonance frequency of the resonance circuit unit; and a control unit for adjusting the resonance circuit unit on the basis of information about the amplitude difference between the high-voltage RF signals and the resonance frequency of the resonance circuit unit; the resonance circuit unit includes: a frequency synchronizing section for synchronizing the drive frequency of the RF signal source and the resonance frequency of the resonance circuit with each other; and an amplitude difference adjustment section for adjusting the amplitude difference between the high-voltage RF signals to a predetermined value; and the control unit controls the amplitude difference adjustment section of the resonance circuit unit to perform adjustment in such a manner that the amplitude difference between the high-voltage RF signals decreases, and controls the frequency synchronizing section of the resonance circuit unit to perform adjustment in such a manner that the resonance frequency of the resonance circuit is aligned with the drive frequency of the RF signal source, on the basis of the information about the amplitude difference between the high-voltage RF signals and the resonance frequency of the resonance circuit unit.