Advances in gas avalanche photomultipliers

Gas avalanche detectors, combining solid photocathodes with fast electron m ultipliers, provide an attractive solution for photon localization over ver y large sensitive areas and under high illumination flux. They offer single -photon sensitivity and the possibility of operation under very intense mag netic fields. We discuss the principal factors governing the operation of g as avalanche photomultipliers. We summarize the recent progress made in alk ali-halide and CVD-diamond UV-photocathodes, capable of operation under gas multiplication, and novel thin-film protected alkali-antimonide photocatho des, providing, for the rat time, the possibility of operating gas photomul tipliers in the visible range. Electron multipliers, adequate for these pho ton detectors, are proposed and some applications are briefly discussed. (C ) 2000 Elsevier Science B.V. All rights reserved.