GB1049533A - Improvements in or relating to electron multiplier devices - Google Patents

Abstract

1,049,533. Electron multipliers. ELECTRIC & MUSICAL INDUSTRIES Ltd. Aug. 13, 1963 [Sept. 4, 1962], No. 33779/62. Heading H1D. An electron multiplier includes a target electrode which has a first surface spaced from and facing an electron source and a second surface which is electron emissive in response to electrons incident on the first surface, and a plurality of dynodes, with respective secondary electron emissive surfaces facing in the same direction as the target second surface, and arranged such that electrons can be directed to them from the target, in succession in cycloidal paths by a magnetic field. Electrons emitted by photocathode 1 are focused by electrodes 2 and 3 upon target electrode 13, which thereby emits from its further surface electrons which pursue cycloidal paths along the dynode array 4 to collector and mesh electrodes 5 and 10, under the influence of the electrode 6 and a crossed magnetic field produced by a permanent or electromagnet mounted outside the square section 8 of the tube; section 7 of the tube is surrounded by magnetic shield 23. Target electrode 13 may include a self-supporting, or wire-mesh-supported, aluminium oxide or magnesium oxide film bearing, on the surface directed away from the photocathode, an aluminium layer and a potassium chloride coating; alternatively, the electrode includes a transparent support bearing a luminescent screen and an electron permeable aluminium layer on the side facing the photocathode, and a phot o emissive layer on the other side.