Electrostatic design and conditioning of a triple point junction shield for a –200 kV DC high voltage photogun [Electrostatic design of a triple point junction shield for a -200 kV DC high voltage photogun using COMSOL]
Nuclear physics experiments performed at the Continuous Electron Beam Accelerator Facility (CEBAF) at the Jefferson Lab require a DC high voltage photogun to generate polarized electron beams from GaAs photocathodes. The photogun uses a tapered ceramic insulator that extends into the vacuum chamber and mechanically holds the cathode electrode. Increasing the operating voltage from nominal –130 kV to –200 kV will provide lower beam emittance, better transmission through injector apertures, and improved photocathode lifetime. This desire to increase the photogun operating voltage led to the design of a triple-point-junction shield electrode which minimizes the electric field at the delicate insulator-metal-vacuum interface and linearizes the potential across the insulator, thus reducing the risk of arcing along the ceramic insulator. Furthermore, this work describes the results obtained using COMSOL® electrostatic-field simulation software and presents the high voltage conditioning results of the upgraded –200 kV CEBAF photogun.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- Grant/Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1489811
- Alternate ID(s):
- OSTI ID: 1475477
- Report Number(s):
- JLAB-ACC-18-2842; DOE/OR/23177-4563
- Journal Information:
- Review of Scientific Instruments, Vol. 89, Issue 10; ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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