The ALS Electron gun is a grid cathode assembly, HEY-171, made by Varian, Eimac Division. The cathode is the dispenser type with a 1 square cm area capable of producing 1.5A peak current. The gun socket was designed and assembled with commercially available components with a grounded grid configuration. The grounding of the grid is implemented using eight chip capacitors arranged in a circular pattern. The cathode is driven by a gated phase locked burst of 125MHz sinusoidal voltage whose amplitude is adjustable to control the cathode current pulse amplitude.

Page contents:

1. Block diagram of the gun electronics system

2. Block diagram of the ground level RF Gate Generator

3. Operation of the Gun Gate Generator

4. Block diagram of the Hot deck RF receiver                                       

5. Photograph of the Ground Level RF Gate Generator

6. Gun socket schematic diagram

7. Photograph of the gun socket

Paper on this subject:

C.C. Lo, The ALS Gun Electronics System, Proceedings of 1993 IEEE PAC, Vol. 4, pp. 3058-3060, LBL 33189

    This block diagram illustrates the operation of the ALS gun electronics system. The key signal for operation is the 125MHz signal derived from dividing 500MHz by a factor of 4. The complex part of the electronics is implemented at ground level. The drive signal is then sent up to the 125kV hot deck via optical fibers.

Front Panel of ground level gun electronics module