Bill Ndhihokubwayo¶
Mixed beam-matter interactions and transport simulations
Applications to the MYRRHA linear accelerator and to the CERN Proton Synchrotron
Abstract¶
The detailed understanding of the beam-matter interactions and their adverse consequences at large-scale accelerator facilities is of crucial importance as they put strong constraints on the performances of the machines and limit the operational margins. For high-intensity machines, such as the Multi-purpose hYbrid Research Reactor for High-tech Application (MYRRHA) facility, the beam losses must be reduced to the lowest possible level and the detailed loss pattern in the machine must be understood to improve the shielding design. For high-energy machines such as the CERN Proton Synchrotron (PS), the detailed study of the beam losses is necessary to reduce the activation of the machine elements and allow long-term operation, safe maintenance, and ultimately a high machine availability. Although the particle-matter interaction processes are well understood and modeled by specialized Monte-Carlo codes, most studies so far make use of multiple simulation codes where the particle tracking is decoupled from the beam-matter interactions, leading to inconsistent or duplicated models and hard-to-maintain analysis codes. In this work Beam Delivery Simulation (BDSIM), an accelerator tracking and particle interaction code, based on Geant4, is used to alleviate these issues while benefiting from state-of-the-art particle tracking and description of beam-matter interactions. A BDSIM model of the MYRRHA linear accelerator is developed and validated, including both the effects of acceleration and beam focusing. For the first time, BDSIM is applied to a realistic model of the CERN PS to form a novel self-consistent approach. The model is used to study the internal beam-dump process and is validated against the MAD-X tracking code. Our initial results confirm prior studies performed for the beam-dump renovation. We obtain new results for the multi-turn beam loss patterns, a significant observable which will be compared with experimental data once the machine operation resumes. A complete and consistent description of the beam-dump mechanisms is derived from these simulations and the results are discussed in detail.