Abstract: Using RFQ as the main accelerator is a possible way to make AMS more compact. It is most important to reduce the energy spread of RFQ accelerator. Based on a theoretical analysis of the energy spread of RFQ shaper section, simulation by using computer code RFQDYN shows that an energy spread of 0.4% can be obtained by optimizing RFQ parameters.

Key words: RFQ accelerator, AMS, energy spread

摘要： 将RFQ作为加速器质谱系统（AMS）的加速器是AMS小型化的一条可能途径,减小RFQ加速器的输出束流能散是实现这一途径的关键。对RFQ加速器成形段部分对束流输出能散影响的分析表明，在减小调制系数、极间电压、同步相位，使各参数匹配的同时，适当地增大纵向聚焦力可显著降低RFQ输出束流能散。利用变参量RFQ动力学模拟程序RFQDYN进行模拟优化，得到输出束流能散为0.4%的RFQ加速器物理设计。

关键词: 射频四极场（RFQ）加速器, 加速器质谱, 能散