Evolution of a beam dynamics model for the transport line in a proton therapy facility
Evolution of a beam dynamics model for the transport line in a proton therapy facility
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DOI：
10.1103/physrevaccelbeams.20.124702
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发表时间：
2017-12-11
影响因子：
1.7
通讯作者：
Schippers, J. M.
中科院分区：
文献类型：
--
作者：
Rizzoglio, V.;Adelmann, A.;Schippers, J. M.
在加速器或束流线的概念设计过程中，一阶束流动力学模型是研究束流特性所必需的。然而，它们只能产生近似的结果。在调试期间，将这些近似结果与测量结果进行比较，如果模型不包括相关物理，则很少会吻合。因此，必须将这个线性模型扩展到包括高阶效应。本文将粒子-物质相互作用的影响纳入瑞士保罗·谢勒研究所（PSI）质子治疗装置的输运线模型。这些光束线的一阶模型提供了光束尺寸、能量损失和传输的近似估计。为了提高设备的性能，需要一个更精确的模型，并利用OPAL（面向对象的并行加速器库）开发了一个多粒子开放源代码束流动力学代码。在OPAL中，库仑散射和能量损失的蒙特卡罗模拟与粒子跟踪是无缝的。除了线性光学外，该模型还分析了无源元件（如衰减器、准直器、散射箔和气隙）对光束发射度和能量扩散的影响。这可以显著提高光束传输和光束特性预测的精度。OPAL模型的准确性已被大量测量证实。
During the conceptual design of an accelerator or beamline, first-order beam dynamics models are essential for studying beam properties. However, they can only produce approximate results. During commissioning, these approximate results are compared to measurements, which will rarely coincide if the model does not include the relevant physics. It is therefore essential that this linear model is extended to include higher-order effects. In this paper, the effects of particle-matter interaction have been included in the model of the transport lines in the proton therapy facility at the Paul Scherrer Institut (PSI) in Switzerland. The first-order models of these beamlines provide an approximated estimation of beam size, energy loss and transmission. To improve the performance of the facility, a more precise model was required and has been developed with OPAL (Object Oriented Parallel Accelerator Library), a multiparticle open source beam dynamics code. In OPAL, the Monte Carlo simulations of Coulomb scattering and energy loss are performed seamless with the particle tracking. Beside the linear optics, the influence of the passive elements (e.g., degrader, collimators, scattering foils, and air gaps) on the beam emittance and energy spread can be analyzed in the new model. This allows for a significantly improved precision in the prediction of beam transmission and beam properties. The accuracy of the OPAL model has been confirmed by numerous measurements.