GB1334527A - Gas filled thyratron type switching discharge tubes - Google Patents

Abstract

1334527 Gas filled thermionic valves ENGLISH ELECTRIC VALVE CO Ltd 13 Feb 1973 46213/70 Heading H1D A gas filled thyratron comprises a cathode, an anode and a control grid; the anode including two electrodes between which a plasma is generated. The anode arrangement prevents damage by positive ion bombardment when the current through the thyratron is reversed. The thyratron is symmetrical about a plane I-I. Each half comprises an anode/cathode 18 including a thermionic cathode 22 with a heater 24 and heat shield 26 and a discharge electrode 28. A control grid 32 comprises a cylindrical section 34, a pair of apertured plates 36, 38 and a member 40 partially filling the apertures. Electrodes 90, 84 of similar construction and with cooling members 42 are maintained at intermediate potential to prevent voltage breakdown. The envelope consists of sections 10, 10a, 10b and is filled with hydrogen, deuterium and tritium. A H 2 reservoir 50 is mounted adjacent the electrode structure and is heated to maintain the gas pressure. A plasma discharge between cathode 22 and electrode 28 is produced by applying a positive potential to electrode 28. The thyratron acts as a switch in an oscillator circuit. A negative potential applied to grid 32 via a transformer 63 prevents firing until a pulse is applied to the transformer. This renders the grid positive, electrons are attracted from the plasma and the gas filling becomes ionized. Positive ions are absorbed in the plasma of the cathode.