多束脉冲作用下韧致辐射转换靶照射量模拟

20MeV的强流脉冲电子束经加速聚焦后轰击韧致辐射转换靶，在产生脉冲X光的同时将大量能量沉积在靶内，导致靶材迅速膨胀飞散。在多个束脉冲作用下，后续脉冲由于靶材密度的降低可能无法产生足够的X光照射量。本文采用Monte-Carlo软件MCNP以及流体动力学软件ANSYSAUTODYN对靶材的动力学响应以及各脉冲所能产生的照射量进行了数值模拟，结果表明，在3个间隔500ns的20MeV、2kA、70ns、束斑1.5mm（FWHM）的电子束脉冲作用下，X光照射量无明显降低。

Simulation of X-ray Dose Produced by Multi-pulse Electron Beam Impacting on Bremsstrahlung Conversion Target

When high-current pulse electron beam of 20 MeV is focused onto the bremsstrahlung conversion target, high intensity pulse X-rays are produced. At the same time, a large amount of energy is deposited into the target, which results in the target material expansion and blowing off. X-rays doses may be reduced significantly when multi-pulse beam interacting with the conversion target, because the density of the target material decreases during the beam pulses. In the paper, the Monte-Carlo code MCNP and hydrodynamic code ANSYS AUTODYN were used to simulate the hydro-response of the target material and the X-rays dose of each pulse. The results show that X-ray doses are only slightly reduced when 3 pulses (20 MeV, 2 kA, 70 ns, spot size 1.5 mm (FWHM) and 500 ns separation) impacting on the conversion target.