Vertical focusing study in the central region of the CYCIAE-100 cyclotron

The vertical focusing is one of the primary problems in the central region of cyclotrons. This focusing effect brought about by the magnetic field is inclined to be weak near the center of the machine due to the fact that the flutter is small, while the electric focusing forces incurred from the dee gaps become very strong. Since the electric focusing effect is dependent on the RF phase, we have proceeded to carry out analytical calculations and numerical simulation about the vertical focusing in the central region of CYCIAE100, including magnetic focusing, electric focusing and the defocusing effect from the space charge effect. All the results have been used for the design of the central region for CYCIAE-100 and a good vertical focusing has been obtained.