The fabrication of bepcii 500 mhz superconducting cavities

Since Nov. 2006, the 500MHz SRF system of Beijing electron positron collider upgrade (BEPCII) has been running stably. But there’s a hidden danger for no spare cavity is existed. If there’s any serious trouble happened on either one of the two operating cavities and cannot be recovered in time, it will affect the operation of BEPCII facility. Spare cavities began to be investigated since 2009. Now three cavities are developed and two of them have been vertical tested at Jan and July 2011, respectively. This paper will briefly present the manufacturing, post-processing and vertical test performance of the cavity.