Design And Development Of A7MeV/U Heavy Ion Cyclotron

A7MeV/U compact heavy ion cyclotron has being under developing at Institute of Modern Physics. The thesis works on the design and development of the cyclotron. Focus on the physical design of the cyclotron and the beam dynamical studies.The design of the cyclotron is based on the electromagnetic fields. The single particle tracking and multi-particle tracking as well as transport matrix method have been used in the design. The design of the cyclotron has been composed by3parts, the central region design, the extraction system design and the axial injection line design. The design of the cyclotron aims on the improvement of the transmission efficiency and the beam qualities. The miniaturization and simplification of the accelerator structures has been considered as well as the running reliability and stability of the accelerator.The design of the central region includes the electrode geometry and the spiral inflector. The beam has been centralized by optimizing the shape of the electrode. The centralization in the central region is better than2mm. The design also insures the axial beam focusing and lager acceptance of phase space. The spiral inflector bends the beam from axil motion to the median plane motion. The design of the spiral inflector focuses on higher transfer efficiency and better beam optics.The design of the extraction system is based on the isochronous fields. Theextraction elements and its’ basic parameters are determined by single particletracking. The parameters are optimized by multi-particle tracking, the beamparameters of extracted beam are also got from multi-particle tracking. Thedifficulties in the design of the extraction system come from the compact space,which makes the design of the extraction elements very difficult for they shouldhave high electromagnetic fields. Meanwhile the beam is extracted from the edge ofthe sector, where the magnetic field changes very quickly, so the extractionefficiency is very low, and extracted beam quality is poor. In order to improve theextraction efficiency and extracted beam quality, a magnetic field gradient correctorwhich composed of a c-iron and a coil is introduced at the edge of sector，then theextraction efficiency increases from28%to47%.The design of the axial injection beam line includes the design of beam analysissystem, the design of the beam transmit system, the design of the optics matchingsystem and the design of the beam modulation system. TRACE3D code is used inthe preliminary design. Beam simulation code SNOP is used to check the design ofthe beam line.The manufacture of the cyclotron components is completed. Some of the testworks of the components are completed. The installation of the cyclotron and thetune of cyclotron components are progressing. Beam commissioning of thecyclotron will soon be.