GB919006A - Improvements in or relating to the control of a pulsed beam of charged particles - Google Patents

Abstract

919,006. Cathode-ray tube circuits. ZEISSSTIFTUNG, CARL, [trading as ZEISS, C. [Firm of]]. April 13, 1961 [April 14, 1960], No. 13248/61. Class 40 (7). [Also in Group XL (a)] In an electron beam generator, the anode 4, Fig. 1, is grounded, a bias is established between the cathode 2 and control electrode 3 to prevent beam generation, intermittent acceleration pulses are applied to both the cathode and the control electrode, and intermittent control pulses are applied between the cathode and control electrode to overcome the bias during a selected portion of each acceleration pulse. The control pulses are keyed to the frequency of the acceleration pulses and are shorter than the acceleration pulses. As shown, bias source 8 and control pulse generator 10 are serially coupled between cathode 2 and control electrode 3 and are energized through isolating transformers 9, 11. Generator 10 is coupled to acceleration pulse generator 7 through a delay line 12 and capacitor 13. In an alternative arrangement, the acceleration pulse generator 17, Fig. 2, is coupled to the primary winding 16 of a transformer having first or second bifilar secondary windings 18, 19. Winding 19 has one terminal coupled to control electrode 3 and the other to ground, and winding 18 has one terminal coupled to cathode 2, the control pulse generator 21 and bias source 20 being serially connected between the other terminal and ground. Generator 21 is coupled to generator 17 through delay line 22. The beam generator may be employed for electron microscopes or for boring, drilling, soldering, welding or other heat treatment of materials.