GB671335A - Circuit for the introduction of electrons into an electron accelerator - Google Patents

Abstract

671,335. Magnetic-induction accelerators. AKT.-GES. BROWN, BOVERI, & CIE. Sept. 22, 1948 [Sept. 23, 1947], No. 24822/48. Class 39 (i). In an electron accelerator with at least one electron injector, the cathode of the injector has for a short period a voltage applied to it which is derived from a saturated current transformer, the primary winding of which is in the circuit formed by the accelerator winding, the starting instant being adjustable by means of an additional current flowing through the saturated current transformer which is displaced in phase relative to the excitation current of the accelerator, and the impedance of the circuit of the additional current being large. The additional current for adjusting the starting instant of the peaked voltage applied to the electrodes of the injector 6, 7, is supplied by a transformer 9 through a resistor 8 to the winding 4 of the saturated current transformer 3. The magnetizing current in the winding 1 of the accelerator is compensated by condensers 2. The currents in the windings 1 and resistance 8 are displaced in phase by about 90 degrees and give an adjustment in phase of the resultant current. In one modification the accelerator is connected across two terminals and the transformer is supplied from a voltage source displaced by 90 degrees in phase from that across the terminals and has an adjustable winding in series with a choke coil which replaces the adjustable resistance of Fig. 1. The choke coil has an inductance at least five times that of the current transformer and a low capacitance winding with a small number of turns. A capacity may replace the choke coil. In Fig. 3 there are two electron injectors 6, 7 and 6<SP>1</SP>, 7<SP>1</SP> with a phase displacement of 180 degrees introducing beams into the accelerator in opposite directions. Thyratrons 14, 14<SP>1</SP> are controlled by the voltage peaks of transformers 3, 3<SP>1</SP> and connect condensers 2 to oscillation circuits including capacities 16, 161 and inductance 17. The starting instant for the voltage peaks can be adjusted by means of the resistors 8, 81. The additional current may flow in a third winding on the saturated current transformers 3, 31.