Ion detection

摘要

A mass analyzer in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyzer; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

主权项

1. An ion detector for a mass analyzer in which ions are caused to form ion packets that oscillate with a period, the ion detector comprising:
a detection arrangement, comprising: a plurality of detection electrodes configured to detect a plurality of image current signals from ions in the mass analyzer; and a preamplifier, wherein the preamplifier is arranged to provide an output signal based on the plurality of detected image current signals, the output signal having a signal-to-noise ratio; and compensation circuitry, arranged to provide at least one compensation signal, each compensation signal being provided to a respective compensatory part of the detection arrangement and being based on one or more of the plurality of detected image current signals; and wherein there is a capacitance between each of the compensatory parts of the detection arrangement and a respective signal-carrying part of the detection arrangement, affecting the signal-to-noise ratio of the preamplifier output signal.