BNL, Upton, Long Island, New York
A prototype ampere-class superconducting energy recovery linac (ERL) is under advanced construction at BNL. The ERL facility is comprised of a five-cell SC Linac plus a half-cell SC photo-injector RF electron gun, both operating at 703.75 MHz. The facility is designed for either a high-current mode of operation up to 0.5 A at 703.75 MHz or a high-bunch-charge mode of 5 nC at 10 MHz bunch frequency. The R&D facility serves a test bed for an envisioned electron-hadron collider, eRHIC. The high-current, high-charge operating parameters make effective higher-order-mode (HOM) damping mandatory, and requires to determination of HOM tolerances for a cavity upgrade. The niobium cavity has been tested at superconducting temperatures and has provided measured dipole shunt impedances for the estimate of a beam breakup instability. The facility will be assembled with a highly flexible lattice covering a vast operational parameter space for verification of the estimates and to serve as a test bed for the concepts directed at future projects.
PKU/IHIP, Beijing
Peking University is striving for constructing a superconducting radio-frequency accelerator test facility (PKU-SETF) to provide coherent radiations [1]. A cryomodule consisting of a China made 9-cell TESLA type cavity was designed and constructed for this purpose, which is expected to provide 15-20 MeV energy gain at an operating temperature of 2K. Some technical issues in the manufacturing progress are reported, including the tungsten inert gas (TIG) welding of the LHe vessel and the superconducting cavity, the demagnetization of the vacuum vessel made of pure iron, and the manufacturing of the main power coupler.