CERN Accelerating science

Article
Title	JAERI 200 kV Electron Gun with an NEA-GaAs Photocathode
Author(s)	Nishitani, Tomohiro ; Hajima, Ryoichi ; Kikuzawa, Nobuhiro ; John Minehara, Eisuke ; Nagai, Ryoji ; Nishimori, Nobuyuki ; Sawamura, Masaru ; Yamauchi, T
Affiliation	(JAERI/FEL, Ibaraki-ken)
Publication	2004
In:	26th International Free Electron Laser Conference and 11th FEL User Workshop 2004, Trieste, Italy, 29 Aug - 3 Sep 2004, pp.e-proc. THPOS23
Subject category	Accelerators and Storage Rings
Abstract	The GaAs photocathode with negative electron affinity surface (NEA-GaAs) has been expected to be low emittance (<0.5 &#960;mm&#12539;mrad) electron beam source. In order to generate low emittance electron beam required from ERL-FEL, we have started the developmental program of a 200keV electron gun with the NEA-GaAs photocathode for the first time in JAERI. An NEA surface has the problem that lifetime is limited by gun vacuum condition and by ion back bombardment between anode- and cathode-electrode. In order to long an NEA surface lifetime, the JAERI 200keV electron gun system consists of a 200kV DC-gun chamber on extreme high vacuum condition and an NEA activation chamber with load-lock system.