학술논문

High voltage processing of the SLC polarized electron gun
Document Type
Conference
Source
Proceedings of International Conference on Particle Accelerators Particle accelerator Particle Accelerator Conference, 1993., Proceedings of the 1993. :3033-3035 vol.4 1993
Subject
Fields, Waves and Electromagnetics
Engineered Materials, Dielectrics and Plasmas
Nuclear Engineering
Robotics and Control Systems
Voltage
Polarization
Electrons
Dark current
Surface cleaning
Protection
Cathodes
Power supplies
Surface contamination
Spectroscopy
Language
Abstract
The SLC polarized electron gun operates at 120 kV with very low dark current to maintain the ultra high vacuum (UHV). This strict requirement protects the extremely sensitive photocathode from contaminants caused by high voltage (HV) activity. Thorough HV processing thus required. An X-ray sensitive photographic film, a nanoammeter in series with the gun power supply, a radiation meter, a sensitive residual gas analyzer and surface X-ray spectrometry were used to study areas in the gun where HV activity occurred. By reducing the electric field gradients, carefully preparing the HV surfaces and adhering to very strict clean assembly procedures, we found it possible to process the gun so as to reduce both the dark current at the operating voltage and the probability of HV discharge. These HV preparation and processing techniques are described.ETX