The Gas Electron Multiplier (GEM) has been recently developed to cope with
the severe requirements of high luminosity particle physics experimentation
. With excellent position accuracy and very high rate capability, GEM devic
es are robust and easy to manufacture. The possibility of cascading two or
more multipliers permits to achieve larger gains and more stable operation.
We discuss major performances of the new detectors, particularly in view o
f possible use for high rate portal imaging and medical diagnostics. (C) 20
01 Elsevier Science B.V. All rights reserved.