Characterization of the PTB ultra-high pulse dose rate reference electron beam
Characterization of the PTB ultra-high pulse dose rate reference electron beam
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DOI：
10.1088/1361-6560/ac5de8
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发表时间：
2022-04-21
影响因子：
3.5
通讯作者：
Kapsch, Ralf-Peter
中科院分区：
文献类型：
--
作者：
Bourgouin, Alexandra;Knyziak, Adrian;Kapsch, Ralf-Peter
目的。本研究旨在展示德国 PTB 设施的超高脉冲剂量率 (UHPDR) 电子束的表征和优化。蒙特卡罗射束模型已开发用于剂量学研究，用于未来 FLASH 放射治疗的研究，并将予以介绍。材料和方法。研究直线加速器产生的 20 MeV 电子束已通过轮廓监视器和磁力谱仪在束线内以及通过金刚石探测器原型在水中进行了表征。蒙特卡罗模型已用于研究六种不同的设置，以在水中实现不同的每脉冲剂量 (DPP) 范围和光束尺寸。水中电子辐射场的特性也通过光束尺寸、质量规格 R (50) 和平坦度来表征。还研究了梁的稳定性。结果。蒙特卡罗模拟和测量的 R (50) 之间的差异小于 0.5 mm。模拟的光束尺寸与测量的光束尺寸一致在 2 mm 以内。已经确定了两种合适的装置用于提供参考 UHPDR 电子束。第一个的特点是 SSD 为 70 厘米，而第二个则为 90 厘米的 SSD 与 2 毫米的铝散射板结合使用。这两种装置安装起来既快速又简单，并且实现了每脉冲 0.13 Gy 至 6.7 Gy 的预期总体 DPP 范围。结论。 PTB 研究加速器产生的电子束在本次调查的四个月期间保持稳定。蒙特卡罗模型已证明在光束尺寸和深度剂量方面具有良好的一致性，并且在光束平坦度方面的一致性在 1% 以内。金刚石探测器原型已被证明是一种很有前途的工具，可用于 UHPDR 电子束的相对测量。
Purpose. This investigation aims to present the characterisation and optimisation of an ultra-high pulse dose rate (UHPDR) electron beam at the PTB facility in Germany. A Monte Carlo beam model has been developed for dosimetry study for future investigation in FLASH radiotherapy and will be presented. Material and methods. The 20 MeV electron beams generated by the research linear accelerator has been characterised both in-beamline with profile monitors and magnet spectrometer, and in-water with a diamond detector prototype. The Monte Carlo model has been used to investigate six different setups to enable different dose per pulse (DPP) ranges and beam sizes in water. The properties of the electron radiation field in water have also been characterised in terms of beam size, quality specifier R (50) and flatness. The beam stability has also been studied. Results. The difference between the Monte-Carlo simulated and measured R (50) was smaller than 0.5 mm. The simulated beam sizes agreed with the measured ones within 2 mm. Two suitable setups have been identified for delivering reference UHPDR electron beams. The first one is characterised by a SSD of 70 cm, while in the second one an SSD of 90 cm is used in combination with a 2 mm aluminium scattering plates. The two set-ups are quick and simple to install and enable an expected overall DPP range from 0.13 Gy up to 6.7 Gy per pulse. Conclusion. The electron beams generated by the PTB research accelerator have shown to be stable throughout the four-months length of this investigation. The Monte Carlo models have shown to be in good agreement for beam size and depth dose and within 1% for the beam flatness. The diamond detector prototype has shown to be a promising tool to be used for relative measurements in UHPDR electron beams.