Three dimensional field calculations compared to magnetic measurements for CERN PSB-CPS transfer line magnets

The transfer line PSB-CPS recombines the four beams from the CERN PS Booster (PSB) into one beam, which is injected into the CERN 26 GeV Proton Synchrotron (CPS). As part of the "PS conversion for LHC" project, some of the magnets in this transfer line have been replaced by new magnets with laminated yokes and higher maximum current. The magnets were built and magnetically measured by TRIUMF as part of a Canadian contribution to the CERN LHC project. Detailed three dimensional mathematical models have been developed for two types of bending magnets. The models are compared to magnetic measurements and it is shown that the integrated homogeneity curves can be calculated from the 3D model with a precision significantly better than one per mill. The mathematical model is then used to predict the influence of shims on the magnetic field.