高能多脉冲辐射照相的复合靶物理分析

Design analysis on composite target of high energy multi-pulse radiography

介绍了电子束与钽靶相互作用的能量沉积解析理论和（钽-碳）复合靶的设计。单靶的某个区域内形成的高温等离子体沿轴的2个方向（±z）溅射而使单靶穿孔，大焦斑束形成较小的孔，小焦斑下靶孔较大而相对光滑。复合靶或修正复合靶可以经受2～3个束脉冲的连续照射。蒙卡模拟计算表明，复合靶或修正复合靶的焦斑尺寸与单靶相同，可用于多脉冲闪光照相。

The analytic theory of the energy deposition of electron beam on the conversion target and the design approach for the composite target are presented. The high temperature plasma formed in the simple target would eject along positive and negative axial directions and make the target perforated. In the same beam energy, the beam with larger focal spot makes smaller ablated cavities with curl edge in the target, hut the beam with smaller spot makes larger ones with relativly smooth edge. The com- posite target and the modified composite target can bear continuous strikes of 2 ～ 3 beam pulses. The Monte Carlo simulation shows that the spot size of bremsstrahlung sources are the same as the electron beam spot size on the target, thus the composite target can be used in the multi-pulse radiography.