GB514938A - Improvements in and relating to electron discharge devices - Google Patents

Abstract

514,938. Electron multipliers. RADIOAKT.- GES. D. S. LOEWE. Feb. 14, 1938, No. 4542. Convention date, Feb. 17, 1937. [Class 39 (i)] The final stages of an electron multiplier, preferably used in combination .with a series of multiplying grids of the ordinary type, consist of semi-cylindrical grid, opposed to a solid, semicylinder of the same diameter and a rod co-axial with them, the collecting electrode being a cylindrical grid, the diameter of which is preferably the geometric mean of those of the rod and the outer electro 19, the object being to diminish capacity in the last stages. Electrons which may be obtained as shown from a photoelectric cathode 9 pass after multiplication at the grids 2 to the system according to the invention which is mounted within a screen 3 which may be at the same potential, as the cathode 9. The system consists of a semicylindrical multiplying grid 1 from which electrons are drawn by the positive potentials on the rod 5, grid 6, and plate 4. The potentials of these four electrodes are respectively 100, 200, 400 and 300 volts, but the grid 6 is of wide mesh and most of the electrons pass through to the secondary emitting surface 4, whence they are drawn back by the grid 6, through which they again pass to the rod 5. This emits further secondary electrons which are collected by the output electrode 6. The lead from the collecting grid 6 is brought out separately from those to the other electrodes and may be connected to an amplifying valve 11.