Mass spectrometer

摘要

A mass spectrometer is disclosed comprising an ion beam attenuator (6) which attenuates an ion beam (1a) repeatedly switching between a zero transmission mode of operation during a time period 4T1 and a non-zero transmission mode of operation during a time period ”T 2 . The degree of attenuation of the ion beam can be varied by varying the mark space ratio ”T 2 /”T 1 . The ion beam attenuator (6) may release ions in packets or pulses but the packets or pulses of ions may be converted into a continuous ion beam by a relatively high pressure ion guide or gas collision cell arranged downstream of the ion beam attenuator.