Superconducting RF activities at Peking University

The RF superconducting group at the Institute of Heavy Ion Physics of Peking University is developing Nb cavities for high-brightness electron sources. A series of efforts has been made since fall 1988 to construct a class 100 laboratory suitable for processing and assembling Nb cavities, as well as to develop equipment and techniques for the design surface treatment and RF test of superconducting cavities. The fields of fundamental and high-order modes, as well as wakefield potentials, were studied using the SUPERFISH, URMEL, and TBCI codes during design. The preparation of the Nb cavity and the structure of the cryostat are described and preliminary results of Q versus temperature are presented and discussed. An accelerating field of 8.6 MV/m was obtained with a Q/sub 0/ of 6.5*10/sup 8/ at 2.25 K. In addition, coaxial and pillbox cavities were designed and constructed to test the RF properties of high-T/sub c/ YBaCuO samples.<>