STROMVERSORGUNG FÜR MULTIPOLAR-MASSENFILTER

摘要

PCT No. PCT/GB92/01961 Sec. 371 Date Jun. 2, 1993 Sec. 102(e) Date Jun. 2, 1993 PCT Filed Oct. 26, 1992 PCT Pub. No. WO93/08590 PCT Pub. Date Apr. 29, 1993.A quadrupole mass filter (1) includes a controllable RF oscillator (7) which follows any drift in the resonant frequency of a resonant circuit means (8), this circuit means (8) amplifying an alternating RF potential from the oscillator (7) and supplying it to the filter electrodes (2, 3, 4, 5). To ensure that the charge to mass ratio of the particles transmitted by the filter remains constant, a signal for controlling the amplitude of the oscillator (7) is corrected in response to any resonant frequency shift. This signal is also fed to DC supply means (12, 13, 15), to ensure that the amplitude of the DC potential applied to the electrodes (2, 3, 4, 5) remains in the correct ratio to the RF potential amplitude so that the filter resolution remains constant.