Electromagnetic FEM analysis of the CERN Proton Synchrotron main magnetic unit

The knowledge of the magnetic field generated by the main magnets of the CERN Proton Synchrotron (PS) is essential for getting better control over optical parameters of the beam. However, it is not possible in practice to predict the synchrotron working point for every set of linear and nonlinear magnetic field. A finite element analysis of the field was used for this purpose. The ANSYS software was used to perform 2D and 3D calculations of the magnetic field. The influence of the iron packing factor on results was investigated and the 2D solution for various currents sets was compared with the experimental data. The 3D model was used for analysing the field along the beam trajectory. Finally, the magnetic field obtained with the 2D analysis was decomposed into multipolar terms and applied in an accelerators design software, MAD, in order to recreate the basic parameters of the accelerator optics. Several limiting factors that could caused discrepancies compared to measured parameters were identified.