The vacuum system design for the APS Upgrade storage ring is subject to a number of challenging performance requirements and interface constraints. Maintaining adequately low residual gas pressure is, of course, crucial but the system has other important functions. These include: management of a substantial amount of unwanted bending magnet radiation, providing exceptional mechanical stability for rf beam position monitors, and being sufficiently robust and maintainable to support beam availability to users on par with that of the existing APS machine. A design which confidently addresses these objectives is nontrivial given the limited space allowed inside of magnets and beam impedance considerations; however, a reasonable solution appears to be at hand. The preliminary design for the vacuum system will be presented along with expected pressure performance given some open design options. Computational tools being used to develop the design and the r&d program that is being conducted to refine and build confidence in the design will also be discussed.
Preliminary Design of the Storage Ring Vacuum System for the APS Upgrade