Development of a Method for Measuring the Radial Component of the Magnetic Field in AVF Cyclotrons

In AVF cyclotrons the median plane of the magnetic field rather often does not coincide with the mid-plane of their magnetic system. To measure the radial component of the magnetic field, equipment based on search coils is developed and used to correct the median plane of the magnetic field. The equipment for Br mapping is described. The Br mapping and shimming results are presented for two proton therapy IBA C230 cyclotrons.