Estimate of Dose and Residual Activity in the SNS Ring Collimation Straight

The collimation system in the SNS ring includes a two‐stage collimator consisting of a halo scraper and an appropriate fixed aperture collimator. This unit is placed between the first quadru‐pole and the first doublet in the collimation straight section of the ring. The entire structure is surrounded by an outer shield structure. The downstream dose to the doublet and the attached corrector magnet will be estimated for normal operating conditions. In addition, the activities of cooling water, tunnel air, and dose to cables will be estimated. The dose at the flange locations will be estimated following machine shutdown. Finally, the implied dose to surroundings during the removal of an exposed collimator will be made.