18 MeV自引出回旋加速器关键技术

Key technologies of 18 MeV self-extraction cyclotron

设计了一台18 MeV的自引出强流回旋加速器,对于自引出系统提供一种可行的设计方案.对于主磁铁,通过“三个判定”约束主磁场的参数变化,完成对主磁铁的设计;对于自引出系统,通过注入相空间来扫描适合粒子引出的相空间,利用梯度校正磁铁增大引出束流的接受度;对于谐波线圈,通过磁场二次谐波变化,分析束流特性并确定谐波线圈的位置,在扫描不同的谐波线圈面电流情况下,得到束流的引出情况,进而将束流的相空间推送到接受度以内.为了让打靶束流的径向和轴向尺寸匹配同时引出更强的束流,选择doublet结构的磁通道并给出设计思路.最终束流的尺寸为30.5 mm×12.9 mm,能够引出的粒子占成功加速粒子的82.62%.

In this work,an 18 MeV self extraction high current cyclotron is designed,which provides a feasible design scheme for the self extraction system.For the main magnet,it is designed by restricting the parameter change of the main magnetic field through“three judgments”.For the self extraction system,the phase space suitable for particle extraction is scanned by injecting the phase space,and the gradient correction magnet is used to increase the acceptance of the extracted beam.For the harmonic coil,through the second harmonic change of the magnetic field,the beam characteristics are analyzed and the position of the harmonic coil is determined.Under the condition of scanning different harmonic coil surface currents,the extraction of the beam is obtained,and then the phase space of the beam is pushed to the acceptance.In order to match the radial dimension and the axial dimension of the target beam and obtain a stronger beam,the magnetic channel of the double structure is selected and the related design idea is given.The final beam size is 30.5 mm×12.9 mm,the particles that can be extracted account for 82.62%of the successfully accelerated particles.