Accumulator ring H^- injection optimization studies

H^- ion injection into an accumulator ring is a limiting process for future high-intensity pulsed spallation neutron sources. To facilitate the injection design process, a method has been developed to access a tracking code, ACCSIM, from within an optimization package. The optimization tool is a C++ interactive driver with steepest decent and genetic algorithm optimization methods and parallel computing capabilities. Some injection parameters varied in the optimization process are the H^- beam size and position, the foil configuration and thickness, and the horizontal and vertical bump time profiles. Constraints and figures-of-merit include maximum allowed foil temperature, maximum allowed space charge tune shifts, maximum allowed foil traversals, and maximum allowed beam losses. Application of this method to accumulator ring injection in the proposed National Spallation Neutron Source (NSNS) is presented.