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Nishimori, Nobuyuki; Hajima, Ryoichi; Iijima, Hokuto; Nagai, Ryoji; Nishitani, Tomohiro*
Proceedings of 41st Advanced ICFA Beam Dynamics Workshop on Energy Recovery Linacs (ERL '07) (CD-ROM), p.11 - 14, 2007/05
An electron gun has been developed at Japan Atomic Energy Agency (JAEA) for the ERL light source project jointly launched by JAEA, KEK, and the Institute for Solid State Physics (ISSP) of the University of Tokyo. The electron bunch is generated from a NEA photocathode upon illumination of a drive laser pulse and is accelerated to 250keV by the DC high voltage applied between the cathode and anode. We have finished high voltage terminal test and started to assemble a preparation chamber for the photocathode. We have also measured life time and quantum efficiency of AlGaAs to find a photocathode having longer life time, higher quantum efficiency and smaller emittance than GaAs. In our preliminary test, AlGaAs has shown twice higher QE and 10 times longer life time than GaAs. In this talk, our current status of the gun development is presented.
Sakai, Hiroshi*; Shinoe, Kenji*; Furuya, Takaaki*; Sakanaka, Shogo*; Suwada, Tsuyoshi*; Takahashi, Takeshi*; Umemori, Kensei*; Sawamura, Masaru
Proceedings of 41st Advanced ICFA Beam Dynamics Workshop on Energy Recovery Linacs (ERL '07) (CD-ROM), p.56 - 61, 2007/05
For the energy recovery linacs (ERLs), strong higherorder-mode (HOM) damping is necessary to achieve high current operations. For this purpose, we have newly designed a 1.3 GHz 9-cell superconducting cavity. The cell shape of this cavity is designed and optimized for the high current ERL operation. The HOMs are extracted through the beam pipes and damped with RF absorbers. Furthermore, an idea of eccentric-fluted beam pipe (EFB) is proposed in order to extract the quadrupole HOMs. In this paper, strategy for the HOM suppression to optimise for the ERL operation and estimated HOM characteristics are described. Other important R&D items are also reported.
