The ideal detector

Focal plane detectors (FPDs) offer a very large increase in collection efficiency of ions compared with the traditional single-slit detector. Several types of FPD are in existence. The integration of a complete high resolution discrete detector FPD system including computer interface on a silicon chip is in line with developments in 'smart' sensors and the device inherits many of the characteristics (e.g. cheapness, reliability, smallness, elimination of cable and instrument clutter, etc.) which have led to the domination of integrated circuits (ICs) in many areas. FPD integration leads not only to miniaturization but also to performance improvement. Use of a fully integrated FPD would be difficult without an associated computer but most modern mass spectrometers rely on computer supervision and the additional task of FPD control is a natural step in miniaturization and simplification of a mass spectrometer. In this paper it is argued that the performance of a discrete detector FPD, fully integrated on silicon excels in most respects over other one-dimensional FPDs and should dominate in the detection of spatially dispersed photons (of wavelength > 200nm), ions, and electrons (collectively called particles) where the high performance of particle counting is required. This conclusion is based on two simple arguments: (a) a high resolution array of counters requires much associated electronics. There is no rase for non-integrated electronics. Non-integrated electronics can only mean greater complexity, cost, size and power consumption with no compensating advantages. (b) continuing high investment in silicon technology will lead to lower costs and increasingly high specification. Performance issues are examined and the current status of research into integrated FPDs is discussed.