Prediction of the Field Distribution in CERN-PS Magnets

The CERN Proton Synchrotron (PS) has a circumference of 628m and operates at an energy of up to 26 GeV. It uses one hundred combined function magnets, with pole shapes designed to create a dipolar and a quadrupolar field component. Each magnet is equipped with a main current circuit and five auxiliary current-circuits, which allows controlling the linear and non-linear magnetic fields. These magnets were installed in the 1950s, and part of the compensating circuits have been added or modified since then, resulting in the fact that detailed measurements of the field distribution in each individual magnet as a function of the six currents are not available. This study is performed to estimate, through deterministic and stochastic calculations, the expected mean value and standard deviation of the field harmonics of the installed magnets as input for beam dynamics simulations. The relevant results can be used to design correction schemes to minimise beam losses in the PS and to enable the acceleration of higher brightness beams required to reach the foreseen Large Hadron Collider (LHC) luminosity targets.