Magnetic fields and beam optics studies of a 250 MeV superconducting proton radiotherapy cyclotron
Magnetic fields and beam optics studies of a 250 MeV superconducting proton radiotherapy cyclotron
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DOI：
10.1016/j.nima.2007.08.237
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发表时间：
2007-11
影响因子：
1.4
通讯作者：
Jongwon Kim
中科院分区：
文献类型：
--
作者：
Jongwon Kim
250 MeV质子放射治疗超导回旋加速器是密歇根州立大学（MSU）为Paul Scherrer研究所设计的。这项工作是基于1994年在密歇根州立大学进行的概念设计。对以前的设计进行了改进，以最终确定磁体配置，并为实际结构优化回旋加速器元件。柱子的螺旋角减小了，引入了新的山边和山谷。使用涉及示意性匀场方案的最小二乘拟合例程对磁场进行高度等时化。由此产生的参考场对于光束光学的精细研究是足够的。光学模拟预测，对于初始相位宽度为20°的光束，可以实现80%以上的提取效率。研究了位于中心区域的垂直偏转器，通过跟踪光束相空间来控制光束强度。实验结果与光学实验结果吻合较好。
A 250MeV superconducting cyclotron for the proton radiation therapy was designed at the Michigan State University (MSU) for use at the Paul Scherrer Institut. This work was based on the conceptual design carried out at the MSU in 1994. The previous design was refined to finalize the magnet configuration and to optimally arrange cyclotron elements for the actual construction. The spiral angle of the pole was reduced, the new hill-edges and valley shims being introduced. The magnetic fields were highly isochronized using a least square fitting routine involving a schematic shimming scheme. The resulting reference field was adequate for the elaborate study of beam optics. The optics simulation predicted that extraction efficiency of above 80% was achievable for a beam with the initial phase width of 20°. The vertical deflector was investigated located in the central region to control the beam intensity with tracking of beam phase spaces. Some measurement results for the constructed cyclotron were found in a good agreement with those of the optics study.