Paper VT-TuA8
APS-Upgrade Storage Ring Vacuum System Design using SynRad/MolFlow+ with Photon Scattering

Tuesday, October 20, 2015, 4:40 pm, Room 230B

The SynRad/MolFlow+ vacuum simulation package from CERN has been used to evaluate a conceptual design of a storage ring vacuum system for the APS-Upgrade project. The design requirements call for a system that can reach sufficiently low pressures within a reasonable commissioning time in order to achieve required beam lifetimes. A SynRad/MolFlow+ simulation of the storage ring vacuum system pressures has been computed which includes photon scattering and predicts photon stimulated desorption outgassing rates from the irradiated vacuum surfaces. The vacuum system design incorporates two important analyses. Synchrotron radiation absorbers are located at critical lattice sites in order to both mitigate high heat loads and to localize the high predicted gas loads so that they can be efficiently removed with discrete pumps. In addition, the residual gas species are calculated to identify regions with high molecular gas concentrations. Vacuum pumping is then designed to mitigate the high mass gas loads and increase beam lifetimes.