GB1470162A - Electron multiplying arrangements - Google Patents

Abstract

1470162 Electron multipliers; electron beam apparatus EMI Ltd 7 Feb 1974 [27 Feb 1973] 9747/73 Heading H1D An electron multiplier has a plurality of parallel plates slit to form parallel elements, alternate ones of which are twisted out of the plane of the plates so as to be perpendicular thereto, the twisted elements in successive plates being- staggered to form separate zig-zag channels. Fig. 1 also includes photocathode 2, transparent electrode 3, electron collecting electrodes 4 and focusing electrode 15 to direct electrons into respective channels. Plates 15 are electrically-conductive, secondary emissive material and may be Be-Cu or Ag-Mg alloys. The lower webs (11), Fig. 2, not shown), of each plate have holes (12), (13), (14), through which insulating support pillars (not shown) are inserted and are secured at either end of the envelope. The upper webs are similarly constructed. Plates 5 may all be formed from a single sheet. The construction ensures secondary electrons are focused at each stage, strike at large angles of incidence, and that light and ion feedback is negligible. Fig. 3 (not shown) includes fibre optic faceplate (16), photocathode (2), support (18) for bundles (17) of fibre optic elements for conducting light from an X-ray machine, and apertured mask (19) whose apertures correspond to the multiplying channels. Multiplication may be of electrons from sources other than photo-emitters.