ABSTRACT
This chapter looks at the detection system—an important area of the mass spectrometer that detects and quantifies the number of ions emerging from the mass analyzer. Since inductively coupled plasma mass spectrometry (ICP-MS) was first introduced in the early 1980s, a number of different ion detection designs have been utilized, the most popular being electron multipliers for low ion count rates and Faraday collectors for high count rates. Another technique that was used on some of the early ICP-MS instrumentation was to utilize two detectors, such as a channel electron multiplier and a Faraday cup, to extend the dynamic range. The operating principles of the channel electron multiplier are similar to those of a photomultiplier tube used in inductively coupled plasma optical emission spectrometry. For some applications, where ultra trace detection limits are not required, the ion beam from the mass analyzer is directed into a simple metal electrode or Faraday cup.
