Simulation on distributed target material impacted by high intensity current multi-pulse electron beam

计算了多脉冲相对论强流电子束入射钽-石墨叠靶的能量沉积和轫致辐射谱.能量沉积采用Geant4程序计算,轫致辐射谱根据基本的辐射理论和蒙特卡罗方法计算.结果显示,各层的热区能量沉积呈由大到小的递减分布,截面轫致辐射分布和电子束径向分布主要受钽层的影响.石墨层的低能量沉积率和高热容能改善叠靶的性能.对于单脉冲,钽-石墨层厚比为1∶1时,石墨能全部吸收相邻钽层的热沉积,轫致辐射效率为35.4％;4脉冲情况下,钽-石墨层厚比应为1∶13,总轫致辐射效率降到19.9％.考虑轫致辐射剂量和质量,钽-石墨两者的厚度比为1∶5时,钽层的总厚度应为1.2 mm;当钽-石墨层厚比为1:10时,钽层的总厚应降到0.7 mm.The bremsstrahlung and energy deposition of multi-pulse high intensity relativistic electron beam injecting into multi-layer tantalum-graphite target are investigated. The energy deposition is calculated by Geant4 code, and the bremsstrahlung by fundamental radiation theory and Monte-Carlo method. The calculated results show the energy deposition in the hotspot of each layer decreases. The emittance and the radial distribution of the bremsstrahlung and electron beam are mostly affected by the tantalum layers. The low energy deposition rate and high heat capacity of graphite layers can improve the thermodynamic properties of the target. For a single pulse, at the tantalum-graphite thickness ratio 1:1, the graphite can absorb all heat deposition of the neighboring tantalum layers, and the bremsstrahlung efficiency is 35.4%. With 4 pulses, the ratio should be 1:13, and the total bremsstrahlung efficiency decreases to 19.9%. Considering the requirement of bremsstrahlung X-ray quantity and quality, the total thickness of tantalum should be 1.2 mm if the Ta-C thickness ratio is 1:5, and 0.7 mm if the ratio is 1:10.国家自然科学基金委员会-中国工程物理研究院联合基金资助项目; 中国工程物理研究院科学技术发展基金; 国家自然科学基金项目EI中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)082125-21292