Halo Simulation in a Realistic Proton Linac Design

A critical part of the design of a high intensity linear accelerator is to keep activation caused by particle loss below an acceptable limit. For bunch currents up to 200 mA it is possible to make a technical layout of a proton linac which allows operation in a non-space charge dominated regime. As a consequence almost no rms emittance increase is obtained in all three planes and the production of halo particles is reduced. A cylindrical bunch stays cylindrical. To examine the process of particles moving from the core into the halo, Monte Carlo simulations with a large number of macroparticles are necessary. Strong transverse-longitudinal coupling is observed. The simulation results are used also to study the effect of halo scraping.