Arcing phenomena on CEBAF RF-windows at cryogenic temperatures

Author

Powers, Tom ; Kneisel, Peter ; Allen, Ray

Author_Institution

CEBAF, Newport News, VA, USA

Volume

3

fYear

1995

fDate

1-5 May 1995

Firstpage

1645

Abstract

During the CEBAF commissioning tests some of the superconducting cavities had light emitting discharges (arcing) which were observed in the guard vacuum space between a warm polymeric RF window and the cold ceramic RF window. A dedicated off-line test system was implemented to investigate the conditions under which arcing may occur and to gain some understanding of the mechanisms leading to this phenomenon through optical spectral analysis. This paper reports on the photoemission spectra observed during the dedicated tests on a single cell 1500 MHz niobium cavity with a ceramic window operated at 10 MV/m and 2 K. The light emission was detected using a spectrometer with an intensified photodiode array. The effect of moving the window away from the beam line using a waveguide elbow is reported

Keywords

accelerator RF systems; accelerator cavities; arcs (electric); electron accelerators; photoelectron spectra; photoemission; storage rings; superconducting cavity resonators; waveguide components; 1500 MHz; 2 K; CEBAF; Nb; Nb cavity; RF-windows; arcing; ceramic RF window; cryogenic temperatures; light emission; photoemission spectra; polymeric RF window; superconducting cavities; Ceramics; Cryogenics; Optical polymers; Photoelectricity; Radio frequency; Spectral analysis; Stimulated emission; System testing; Temperature; Vacuum arcs;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 1995., Proceedings of the 1995

Conference_Location

Dallas, TX

Print_ISBN

0-7803-2934-1

Type

conf

DOI

10.1109/PAC.1995.505314

Filename

505314