MASS SPECTROMETER

摘要

A mass spectrometer is disclosed comprising an ion beam attenuator which attenuates an ion beam repeatedly switching between a zero transmission mode of operation during a time period .DELTA.T1 and a non-zero transmission mode of operation during a time period .DELTA.T2. The degree of attenuation of th e ion beam can be varied by varying the mark space ratio .DELTA.T2/.DELTA.T1. The ion beam attenuator may release ions in packets or pulses but the packet s or pulses of ions may be converted into a continuous ion beam by a relativel y high pressure ion guide or gas collision cell arranged downstream of the ion beam attenuator.