Magnetic and optics modeling of accelerator's main magnets and validation via beam-based measurements: a case study at the CERN Proton Synchrotron

Digital twins of main accelerator magnets play a vital role in the design, operation, and development of particle accelerators, as well as in optimizingbeam performance. This involves the development of accurate magnetic models to predict the field distribution within the magnet aperture, along with optics models to predict the beam dynamics around the machine. The CERN Proton Synchrotron (PS) accelerator features 100 combined-function Main Unit (MU) magnets, generating the main magnetic field in the machine. The modeling of these magnetic units is a unique challenge, aiming to capture the multipolar field distribution within the aperture and the non-linearities from saturation of the iron yoke and the presence of air gaps between consecutive iron blocks within the same unit. Over the past decades, various e!orts have aimed to create accurate digital twins of the PS-MU, striving to incorporate the complexities of their magnetic and optical behavior. Operation and optics modeling of the PS-MUs have been historically carried out with empirical beam-based studies. This thesis proposes to evaluate whether, starting from a proper magnetic model and using the predicted harmonics as input to optics simulations, it is possible to accurately predict the beam dynamics behavior in the PS. The predictions from the combined magnetic and optics models are later benchmarked with dedicated beam-based measurements. This work also explores the implications of magnetic length saturation elects on momentum computation, providing valuable operational insights into the interplay between magnetic and beam optics modelling, showing the potential of the developed PS-MU digital twins to optimize machine performance.