GB503359A - Improvements in or relating to electron multipliers - Google Patents

Abstract

503,359. Electron - oscillators. FARNSWORTH TELEVISION, Inc. Feb. 28, 1938, No. 6213. Convention date, March 22,1937. [Class 39 (i)] In electron multipliers, the cloud of electrons is oscillated against and from a secondary electron emitting cathode, and a part of the cloud is utilized to maintain the oscillation while another part is withdrawn into an equipotential space in an external work circuit. In the construction shown in the Figure, a cylindrical cathode 4, treated to have secondary electron emission on its inner surface, and a concentric anode 5 formed of fine refractory wire 6 wound on supports 7 are mounted in an envelope 1. At one point, preferably midway of its length, the cathode has an opening 9 covered with a screen, and on the other side of the opening, in a lateral extension 11 of the envelope, is disposed the open end of a tubular collecting electrode 10 which is closed at its other end. A resonant circuit 14 is connected between the anode 6 and the earth, and the cathode has a radio frequency earth through the condenser 15. Collecting electrode is maintained at a relatively high potential by a source of potential 16 in series with a resonant circuit 17, thus providing very little coupling between 10 and 6. In a modification, Fig. 3 (not shown), the electrode 10 is fed by the high potential source 16 through a radio frequency choke and a lead which passes into the envelope through the side wall. A tubular conductor is-slipped over the end of the envelope extension 11 and is capacitatively coupled with the electrode 10.