紧凑型回旋加速器物理问题及调束技术

Physical problems and beam test of compact cyclotron

介绍了紧凑型回旋加速器CYCIAE-100的特点及设计过程中重点考虑的一些物理问题,如紧凑型直边扇磁铁结构的轴向聚焦、异性高频谐振腔的设计、空间电荷效应等。研究了该加速器的调束技术,包括调束方案、诊断设备布局及径向靶测量的束流信息、物理图像。CYCIAE-100的主磁铁设计中,为降低磁铁和高频腔的加工难度而采用直边扇形磁极,为解决直边扇形磁极在大半径处的轴向聚焦力下降的问题,采用变气隙技术,从而有效提高轴向聚焦力。采用自行开发的基于PIC技术的宏离子模拟程序OPAL-CYCL进行了空间电荷效应的研究,结果表明,CYCIAE-100的极限流强为10mA。

This paper introduces the features of the compact cyclotron CYCIAE-100 and some key physical issues in the de- sign, including the vertical focusing of straight sector magnet structure, design of the special-shape RF resonator, space charge effect, etc. For the main magnet of CYCIAE-100, the straight sector magnet is adopted in the design to reduce the difficulties of fabricating the magnet as well as the RF cavity. Meanwhile, given the fact that the vertical focusing decreases at large radii for the straight sector magnet, the variable hill gap technology is adopted to effectively improve the vertical focusing. Space charge effect study have been carried out with the independently developed code OPAL-CYCL based on the PIC technology, and the result shows that the current limit for CYCIAE-100 is 10 mA. In-depth study results on the beam test of the machine are also described in the paper, including the tuning scheme, diagnostics device layout, beam data measured from the radial probe, and physical figures.