Vacuum System Design for BL11B Front End of SSRF

The front end vacuum system of the beamline in the synchrotron radiation facility can not only transfer the different working vacuum environment of each beamline equipment to the ultra-high vacuum state of the storage ring, but also protect the vacuum of the storage ring from damage when necessary through the vacuum interlock. This paper introduces the design and commissioning method of the front end vacuum system for the hard X ray spectroscopy beamline(BL11B), mainly extended from the aspects of vacuum material selection, equipment configuration, gas load analysis, system layout and pressure distribution calculation, vacuum interlock and the way for commissioning. The static and dynamic pressure distribution of the front end was simulated, and the pressure results of the pump station at the interface with the storage ring were 1.5×10^-8 Pa(static) and 9×10^-8 Pa(dynamic),both of which were equal or superior to the design indexes. It is proved that the method is reliable in the project implementation.