Collimators and beam dumps for the APS-upgrade storage ring - 25478

Argonne's Advanced Photon Source is planning a major upgrade that will increase the storage ring current from the present 100 mA to 200 mA and decrease the beam lifetime due to high charge-per-bunch and substantially smaller transverse beam size. Collimators in the horizontal plane around the storage ring will be used to control beam losses. These collimators will also serve as whole beam dumps in cases where the stored beam must be dumped for machine protection. Another feature of the Upgrade is swap-out injection, in which a stored electron bunch will be extracted to a dedicated swap-out dump when its charge falls to about 90% of the initial value and immediately replaced with a new bunch. Since particle losses will be concentrated in these collimators and beam dumps, there is the potential for high dose rates around these locations and for activation of nearby accelerator components. This paper contains a brief summary of the APS Upgrade, discusses electron losses in the storage ring, and presents calculations of dose rates and induced activity around the collimators and beam dumps. (authors)