Optimization of the parameters in the RHIC single crystal heavy ion collimation

In the framework of the project to design and test a collimation system prototype using a bent channeling crystal for cleaning of the RHIC heavy ion beam halo, we have studied the optimal length and bending angle of a silicon [110] single crystal proposed to be a primary element situated upstream of the traditional heavy amorphous collimator. Besides the matters of the channeling and collimation efficiency, we also looked into the impact the crystal may have on the non-channeled particles that go on circulating in the ring, so as to reduce the momentum offset of the particles scattered of the crystal.