JAEA/ERL, Ibaraki
Energy Recovery Linacs (ERL) have been successfully operated in three high-power FEL facilities, Jefferson Laboratory (JLAB) IR FEL Upgrade, Japan Atomic Energy Agency (JAEA) FEL and Budker Institute of Nuclear Physics (BINP) THz FEL. The ERLs are now considered a promising candidate for uses as high-power FELs, synchrotron radiation sources, electron cooling devices, electron-ion colliders and Compton X/gamma-ray sources. All these applications are based on the excellent feature of the ERL that is simultaneous attainment of multiple beam parameters: small emittance, short bunch duration and high-average current. In order to overcome technological challenges and realize the above future ERL applications, several R&D efforts have been launched in the world. In this paper, we overview the current status of these R&D programs and envision the future of ERLs.
KEK, Ibaraki
JAEA/ERL, Ibaraki
The compact ERL, cERL, is a project to test an energy recovery linac (ERL) with 60 MeV and 100 mA electron beam to generate synchrotron radiation with smaller emittance and shorter pulse length. The design work of the cERL injector has been carried out using a space charge simulation code. The injector consists of 500 kV photo cathode DC gun, two solenoid magnets, buncher cavity, three super conducting RF cavities and merger section to return pass. It generates an electron beam with -77 pC bunch charge and 1.3 GHz repetition rate. Our target value of emittance is less than 1 mm mrad with the bunch length of 1 mm at the exit of the injector. The parameter optimization of the injector using the multi objected method has been carried out to obtain the minimum emittance. The simulation results will be presented in detail.
JAEA/ERL, Ibaraki
KEK, Ibaraki
A 250-kV, 50-mA electron gun has been developed at JAEA for establishing fundamental technologies to generate and evaluate a ultra-small emittance beam, which is required for future ERLs such as a coherent X-ray source and a high-flux gamma-ray source. The gun has been assembled and the first photo-current was obtained from a cathode of NEA-GaAs. Apparatuses for beam measurements has been installed. We plan to measure the transverse emittance by a double-slit configuration and the temporal profile with a deflecting cavity.
KEK, Ibaraki
JAEA/ERL, Ibaraki
JASRI/SPring-8, Hyogo-ken
ISSP/SRL, Chiba
UVSOR, Okazaki
HU/AdSM, Higashi-Hiroshima
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
AIST, Tsukuba
Future synchrotron light source project using an energy recovery linac (ERL) is under proposal at the High Energy Accelerator Research Organization (KEK) in collaboration with several Japanese institutes such as the JAEA and the ISSP. We are on the way to develop such key technologies as the super-brilliant DC photo-injector and superconducting cavities that are suitable for both CW and high-current operations. We are also promoting the construction of the Compact ERL for demonstrating such key technologies. We report the latest status of our project, including update results from our photo-injector and from both superconducting cavities for the injector and the main linac, as well as the progress in the design and preparations for constructing the Compact ERL.
ISSP/SRL, Chiba
JAEA/ERL, Ibaraki
KEK, Ibaraki
A compact ERL (energy recovery linac) is planned in Japan in order to demonstrate excellent ERL performances and to test key components such as low-emittance photocathode gun and superconducting RF cavity. We studied and optimized the compact ERL optics (except the injector part) to generate a subpico-second bunch in bunch compression mode and to preserve the beam emittance in normal and low-emittance mode. As a result, we could obtain a very short bunch of about 50 fs with a charge of 77 pC in bunch compression mode and almost keep the normalized emittance of 0.1 mm mrad with a charge of 7.7 pC in low-emittance mode. We also designed it to achieve efficient energy recovery at the superconducting RF cavities and to transport the beam to the dump section without serious loss. The design study of the compact ERL optics was carried out with the simulation code Elegant, including CSR(coherent synchrotron radiation) effects. In this paper, we will present the results of the beam optics study for the compact ERL.
JAEA/FEL, Ibaraki-ken
KEK, Ibaraki
JAEA/ERL, Ibaraki
HU/AdSM, Higashi-Hiroshima
Nagoya University, Nagoya
A 500-kV, 10-mA photocathode DC gun has been designed and is now under fabrication by the collaboration efforts of JAEA, KEK, Hiroshima Univ. and Nagoya Univ. The Cockcroft-Walton generator and the ceramic insulator are installed upright in the SF6 tank. We have adopted a multiple-stacked cylindrical ceramic insulator, because this type of ceramic insulator has shown good stability and robustness at the 200-kV Nagoya polarized gun and the 250-kV JAEA FEL gun. All the vacuum chambers are made of titanium alloy with very low out-gassing. The Cockcroft-Walton generator, the ceramic insulator, the vacuum chambers will be fabricated by April 2009 and a high-voltage test will be started soon later. Up-to-date status of the gun development will be presented in detail.