A mass spectrometer system can include a mass analyzer operable to mass transmit streams of ions to a detector in a mass dependent fashion for measurement of ion flux intensity. An ion attenuator can be located in the extraction region between the mass analyzer and detector, downstream of the mass analyzer, and can be operable to provide selective attenuation of the ion beam by attenuating ion flux intensity also in mass dependent fashion. Higher concentration ions can be selected and attenuated, while other lower concentration ions can be left unattenuated. Different ions can be attenuated to different degrees. Locating the ion attenuator downstream of the mass analyzer so that the ion beam is already mass differentiated when attenuated can avoid mass discriminatory effects associated with ion beam attenuators. Selective attenuation of only certain ions but not others can extend the dynamic range of the detector without necessarily sacrificing detector sensitivity.