Demonstration of tailored energy deposition in a laser proton accelerator
Jungao Zhu, Minjian Wu, Kejun Zhu, Yixing Geng, Qing Liao, Dongyang Li, Tong Yang, Matthew Easton, C. C. Li, Xiaohan Xu, Yinren Shou, Jinqing Yu, Zheng Gong, Yuan Zhao, Pengjie Wang, D. H. Wang, Li Tao, C. E. Chen, Wenjun Ma, Haiyang Lu, T. Tajima, G. Mourou, Chen Lin, X. Q. Yan
Abstract
In order to implement radiotherapy based on a laser accelerator, it is necessary to precisely control the spatial distribution and energy spectrum of the proton beams to meet the requirements of the radiation dose distribution in the three-dimensional biological target. A compact laser plasma accelerator has been built at Peking University, which can reliably generate and transport MeV-energy protons with a specified energy onto the irradiation platform. In this paper, we discuss several technologies for the accurate control of a laser-accelerated proton beam with large divergence angle and broad energy spread, including the determination of the beam source position with micron accuracy, a tuning algorithm for the transport line which we refer to as ``matching-image-point two-dimensional energy analysis'' to realize accurate energy selection, and the control of beam distribution uniformity. In the prototype experiment with low energy protons and 0.5-Hz irradiation rate, a tailored energy deposition is demonstrated, which shows the potential feasibility of future irradiation based on laser-accelerated proton beams.