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 inter face 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, e tc.) 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 di fficult without an associated computer but most modern mass spectromet ers rely on computer supervision and the additional task of FPD contro l is a natural step in miniaturization and simplification of a mass sp ectrometer. In this paper it is argued that the performance of a discr ete detector FPD, fully integrated on silicon excels in most respects over other one-dimensional FPDs and should dominate in the detection o f spatially dispersed photons (of wavelength >200nm), ions, and electr ons (collectively called particles) where the high performance of part icle counting is required. This conclusion is based on two simple argu ments: (a) a high resolution array of counters requires much associate d electronics, There is no case for non-integrated electronics, Non-in tegrated 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 increas ingly high specification. Performance issues are examined and the curr ent status of research into integrated FPDs is discussed.