A mass spectrometer is described that includes a multipole configured to pass an ion stream, the ion stream comprising an abundance of one or more ion species within stability boundaries defined by (a, q) values. A detector formed by a plurality of dynodes is configured to detect the spatial and temporal properties of the abundance of ions, where each dynode arranged such that it is struck by ions in a known spatial relationship with the ion stream. The detector also includes a plurality of charged particle detectors, each associated with one or more of the plurality of dynodes. A processing system is configured to record and store a pattern of detection of ions in the abundance of ions by the dynodes in the detector.