SNS Beam-in-Gap Cleaning and Collimation

The Spallation Neutron Source (SNS) under construc- tion at Oak Ridge National Laboratory will operate with very high beam power and very strict beam loss require- ments. A two stage collimation system will be used in the accumulator ring to localize beam loss and keep residual ra- diation to a level that will allow for hands-on maintenance of the machine. The collimators will also be used in con- junction with a set of fast kickers to remove the beam from the gap before the rise of the extraction kickers. We have installed a full-scale collimation package into the ORBIT particle-in-cell tracking code, and have used it optimize both the collimation system and the beam-in-gap cleaning process. Results of the studies are presented here.