Simulations for SNS ring commissioning

In preparation for SNS ring commissioning, a number of operational issues have been studied using the ORBIT Code and other simulations. These include beam injection without the use of time-dependent painting, detailed tracking through the extraction septum and ring-to-target transfer line (RTBT) with fully correct geometry, a worst case scenario for beam intensity at the target and extraction dump, quadrupole current constraints in the RTBT, quadrupole settings for RTBT fault studies, and studies of H⁰, H^-, and circulating beam trajectories in the injection region. All the ORBIT studies incorporated detailed physics models including beam-foil interactions, symplectic single particle tracking, space charge and impedances, and losses due to apertures and collimation.