CRYOGENIC SYSTEM FOR BEPCII SUPERCONDUCTING CAVITIES

In order to improve the luminosity of the Beijing electron positron collider, two KEKB type 500MHz superconducting cavities are adopted in the upgrade project which is named as BEPCII. These two cavities are installed in e+ and e- ring, respectively. They are cooled in liquid helium bath contained in a vacuum insulated vessel. Cryogenic system is designed and constructed to provide the superconducting operating circumstance for the cavities. This paper is dedicated to briefly introduce the BEPCII rf side cryogenic system.