SIMULATION, GENERATION, AND CHARACTERIZATION OF HIGH BRIGHTNESS ELECTRON SOURCE AT 1GV/M GRADIENT.
This paper describes computer simulations and measurements on an electron bunch from a pulsed, high gradient gap. MAFIA and PBGUNS were used to calculate the emittance, brightness and energy spread of the electron beam for peak currents ranging from 10A to 1 kA and pulse durations ranging from 0.3 ps to 10 ps. Under optimum conditions, normalized emittance of 10{sup -7} {pi} m-rad, beam brightness of 3 x 10{sup 15} A/(m-rad){sup 2} and energy spread of 0.15% were obtained. A pulsed high voltage with 1 MV amplitude, and {approx}1 ns duration was applied to the diode with an interelectrode gap ranging from 2 mm to 0.5 mm. Copper cathodes with three different surface preparations; diamond polished, diamond turned and chemically cleaned, have been tested for their voltage hold-off properties under this high gradient and the Fowler-Nordheim plots were generated. The diamond polished OFC class II copper was shown to consistently produce lower dark current and higher hold-off voltage. Photoemission studies have been made using light from a KrF excimer. The field enhancement factor for photoemission was calculated to be 5, an order of magnitude smaller than the dark current beta for a similar surface.
- Research Organization:
- BROOKHAVEN NATIONAL LABORATORY (US)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 15016662
- Report Number(s):
- BNL-66464; R&D Project: LS04; KA0403; TRN: US0502793
- Resource Relation:
- Conference: 1999 PARTICLE ACCELERATOR CONFERENCE, NEW YORK, NY (US), 03/29/1999--04/02/1999; Other Information: PBD: 29 Mar 1999
- Country of Publication:
- United States
- Language:
- English
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