Rosalie Dantinne¶
Fast extraction beam losses at the CERN proton synchrotron
Abstract¶
Radiation and machine protection considerations are becoming more critical, as the energy reached by particle accelerator beams increases. Among all beam manipulations, extraction is one of the most challenging. The losses it induces must be reduced to the lowest possible level and the associated dose depositions understood to improve shielding infrastructure. Simulations of both beam tracking and particle-matter interactions by Monte Carlo methods are necessary to accurately determine beam loss patterns and their associated secondary radiation. Beam Delivery Simulation (BDSIM) addresses this need by offering a code that combines the simulation of primary and secondary particle tracking within accelerator-based systems and their interactions with matter. Default beamline elements are provided by BDSIM to simplify the construction of a machine model. However, the possibility of building a custom geometry-based model remains to better represent the material mass distribution. In this work, an existing CERN Proton Synchrotron (PS) model dedicated to the simulation of the fast beam extraction towards the Neutron Time-of-Flight (n-TOF) facility is improved. The integration of custom geometries for the 100 main magnet units, previously initiated, is completed by correcting their associated trajectory problems. The actual apertures of the beampipe components are specified. A comparison with a experimentally validated MAD-X model allows the optical validation of the BDSIM model. The PS model enables the fast extraction beam loss study using BDSIM to be carried out. Putting in perspective simulation results with real PS Beam Loss Monitors (BLM) measurements suggests model improvement and adaptations that could increase its realism and allow its predictions to be compared with experimental data.