The Design of Magnetic Field Measurements System for CYCIAE-100

The CYCIAE-100 Cyclotron is the main part of the BRIF project at China Institute of Atomic Energy. It is an isochronous compact cyclotron for the acceleration of H-, and it will provide proton beam of 75 MeV ~ 100 MeV with an intensity of 200 ??A ~ 500 ??A. The magnetic pole has the radius of 2000 mm and the magnetic gap is changing gradually from inner radius to outer radius. The maximum filed is 1.3 T and required average isochronous field accuracy is less than 10^-4. The difficulties for the design of the magnetic filed measurements device is increased not only due to the field accuracy but also due to the very small space for the compact cyclotron compared with normal machine. This paper describes the field measuring system based on the Hall-probe that has been used for the mapping of field and provides the data for shimming of the cyclotron magnet. The azimuthal and radial position of hall probes will be obtained by optical encoder and linear grating, respective. The overall measurement was estimated to be in the range of ??0.01%.