Effects of injection beam parameters and foil scattering for CSNS/RCS

The China Spallation Neutron Source （CSNS） uses H- stripping and phase space painting metnocl co fill a large ring acceptance with a small emittance linac beam. The dependence of the painting beam on the injection beam parameters was studied for the Rapid Cycling Synchrotron （RCS）. The simulation study was done for injection with different momentum spreads, different rms emittances of the injection beam, and different matching conditions. Then, the beam loss, 99% and rms emittances were obtained, and the optimized injection beam parameters were given. The interaction between H- beam and stripping foil was studied, and the effect of foil scattering was simulated. The stripping efficiency was calculated and the suitable thickness of stripping foil was obtained. In addition, the energy deposition on the foil and the beam loss due to the foil scattering were also studied.