近代物理研究所针对改善兰州重离子加速装置注入器(HIRFL-SFC)引出束流的品质, 将主要考虑改进高频系统以提高Dee盒的加速电压、增加一个相位狭缝和采用平顶波加速等。其中采用平顶波加速可以有效地减小扇形聚焦回旋加速器(SFC)引出束流的能散并且提高其自身的传输效率。采用回旋加速器束流模拟程序AGORA对SFC进行模拟计算, 并比较有无平顶波加速系统下束流品质的变化。结果表明, 采用平顶波加速后, SFC的引出束流能散明显减小, 而且在引出偏转板入口处束流的径向尺寸及圈间距满足单圈引出的条件。

It is planned to upgrade the HIRFL-SFC system for improving the quality of extracting beam and making it matched with the separated sector cyclotron (SSC) of the downstream accelerator. The methods mainly include increasing the accelerating voltage of Dee, equipping phase slit or using flattop acceleration system. The flattop acceleration system is a key method to reduce the energy spread and enhance the transmission efficiency. This paper calculates the beam quality of sector-focused cyclotron (SFC) using the cyclotron beam simulation program AGORA and compares the results obtained with and without flattop acceleration system. The results show that the energy spread reduces sharply with flattop system. The beam width in the radial direction and the turn separation meet the requirements of single turn extraction at the entrance of extraction deflector.