GB565864A - Improvements in and relating to magnetic induction accelerators - Google Patents

Abstract

565,864. Discharge apparatus. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 15, 1943, No. 759. Convention date, Jan. 20, 1942. [Class 39 (i)] A magnetic induction accelerator or " betatron " has means responsive to the strength of the cyclically varying magnetic field to switch on electron-injecting means and orbitdispersing means at appropriate points-in the cycle. The means may comprise an electronic switch 40, Fig. 1, disposed in the fringing field of polepieces 15, 16 and consisting of cathode 42, Fig. 4, concentrating electrode 43, accelerating electrode 45 connected to apertured screen 54, deflecting plates 51, 52 and 59, 60 and collecting anodes 56, 64. The electron beam, as its deflection by the rising magnetic field increases, strikes successively anode 56, to energize the electron-injector circuit (Fig. 6), and anode 64 to energize the orbit-dispersing circuit (Fig. 7). Both circuits use gas-discharge relays 72 which, when rendered conducting, connect a charged condenser 74 either to resistor 75 which energizes electron gun 28, 29, 30, or to series connected coils 90-93 ; of the latter, 90, 91 are the orbit-dispersing coils and 92, 93 are coils compensating induction effects and wound outside the orbit, as shown in Fig. 1. The timing of the switch is effected by (1) manually adjusting of the whole switch within the fringing field by screw 122, (2) varying the current in auxiliary coil 135 wound on the envelope; (3) adjusting bias of deflecting plates 51, 52 and 59, 60.