Advances in gas avalanche photomultipliers

Gas avalanche detectors, combining solid photocathodes with fast electron multipliers, provide an attractive solution for photon localization over very large sensitive areas and under high illumination #ux. They o!er single-photon sensitivity and the possibility of operation under very intense magnetic "elds. We discuss the principal factors governing the operation of gas avalanche photomultipliers. We summarize the recent progress made in alkali-halide and CVDdiamond UV-photocathodes, capable of operation under gas multiplication, and novel thin-"lm protected alkaliantimonide photocathodes, providing, for the "rst time, the possibility of operating gas photomultipliers in the visible range. Electron multipliers, adequate for these photon detectors, are proposed and some applications are brie#y discussed. ( 2000 Elsevier Science B.V. All rights reserved.