New high power linacs and beam physics

New high-power proton linacs must be designed to control beam loss, which can lead to radioactivation of the accelerator. The threat of beam loss is increased significantly by the formation of beam halo. Numerical simulation studies have identified the space-charge interactions, especially those that occur in rms mismatched beams, as a major concern for halo growth. The maximum-amplitude predictions of the simulation codes must be subjected to independent tests to confirm the validity of the results. Consequently, we compare predictions from the particle-core halo models with computer simulations to test our understanding of the halo mechanisms that are incorporated in the computer codes. We present and discuss scaling laws that provide guidance for high-power linac design.