APTR质子同步加速器RFQ直线注入器的优化设计

Upgrade of RFQ injector system for proton synchrotron at Shanghai Advanced Proton Therapy Facility

为实现质子治疗装置的国产化和小型化,基于已完成安装调试的上海先进质子治疗装置(APTR),开展质子治疗注入器系统的升级设计研究,利用PARMTEQM设计软件和快聚束策略,针对APTR同步加速器RFQ直线注入器进行动力学设计模拟。RFQ工作频率为325 MHz,流强18 mA,对从离子源引出的低能质子束流进行匹配俘获、横向聚焦、纵向聚束和预加速,引出能量为3.0 MeV。通过优化预注入器RFQ动力学设计方案和极头参数,有效避免参数共振,减小束流损失,使其整体传输效率达到98.0%,在水平和垂直方向上的发射度增长分别为1.2%和3.3%,出口束流满足下一级腔体的注入需求,开展设计模拟验证和相关冗余度分析,为质子同步加速器的治疗设备和直线注入系统提供参照依据。

The Shanghai Advanced Proton Therapy Facility(APTR)project,proposed by the Shanghai Institute of Applied Physics(SINAP)of Chinese Academy of Sciences,has finished in the commissioning stage.As the key component of APTR complex,the injector system is upgraded to accelerate proton beam to 7.0 MeV in the context of comprehensive localization and miniaturization.To pre-accelerate,longitudinally bunch and transversely focus the lowenergy proton beam from ion source,a pre-injecting system Radio-Frequency Quadruple(RFQ)was designed.Based on fast bunching strategy,this RFQ,operated at 325 MHz,accelerates proton particles to 3.0 MeV.The phase advance has been taken into consideration,and parametric resonance has been carefully avoided by adjusting the vane parameters.The whole transmission efficiency has been optimized to 98.0% to meet the machining requirements and the emittance growth in horizontal and vertical directions are about 1.2%,3.3% along the entire cavity.This paper mainly introduces the beam dynamics design schemes,main parameter selections,simulation results and tolerance analysis.It can provide important theoretical base for linear injection system of proton synchrotron-based therapy facility.