Document Type

Article

Publication Date

10-2018

DOI

10.1063/1.5048700

Publication Title

Review of Scientific Instruments

Volume

89

Pages

104703 (6 pages)

Abstract

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. 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. Published by AIP Publishing.

Comments

NOTE: Publishers version/PDF may be used on author's personal website, arXiv, institutional website, institutional repository, funders designated repository or private forums on social academic network after 12 months embargo.

Original Publication Citation

Palacios-Serrano, G., Hannon, F., Hernandez-Garcia, C., Poelker, M., & Baumgart, H. (2018). Electrostatic design and conditioning of a triple point junction shield for a -200 kV DC high voltage photogun. Review of Scientific Instruments, 89, 104703. doi:10.1063/1.5048700

ORCID

0000-0002-5331-6127 (Palacios-Serrono)

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