基于Z箍缩X射线源的热-力学效应实验

材料或结构对强脉冲X射线的响应如热激波的传播和喷射冲量等，统称为X射线热-力学效应，在抗辐射加固研究、天体物理、行星科学等领域具有重要应用。利用驱动电流近10 MA脉冲功率装置上的丝阵Z箍缩X射线源开展了初步的热-力学效应实验。采用20 mm直径的双层铝丝阵产生了约230 kJ的X射线总辐射能，其中铝的K壳层产额约为30 kJ，距离源中心5 cm处的样品上的X射线能注量为732 J/cm2。受辐照样品为厚度2 mm、直径10 mm的铝制圆盘，其背面设置有铝衬套，样品与衬套的总质量为585 mg。采用全光纤光子多普勒测速（PDV）系统来测量受辐照样品后表面的运动过程。PDV测量的样品后表面速度历程显示，当热激波到达后表面时的自由面速度为2.12 km/s，样品最终的整体运动速度为180 m/s。根据冲击波关系式以及动量守恒原理，推导出X射线在样品中产生的热激波应力为19.2 GPa，单位面积上的喷射冲量为1341 Pa·s，进而由喷射冲量和X射线能注量测量结果可以推出冲量耦合系数为1.83 Pa·s·cm2/J。同时，对实验测量结果的可靠性和不确定度进行了讨论和分析。这些实验结果初步验证了将PDV技术应用于热-力学效应研究的可行性。

Experiments for thermomechanical effects based on Z-pinch X-ray sources

Responses of materials and structures to intense pulsed X-ray radiation, such as thermal shock wave propagation and blowoff impulse generation are referred to collectively as X-ray thermomechanical effects, which have been applied to radiation hardening, astrophysics, and planetary science. Preliminary experiments for thermomechanical effects have been performed utilizing wire array Z-pinch X-ray sources on a pulsed power facility with a drive current of about 10 MA. A total X-ray radiation energy of about 230 kJ was produced by a nested aluminum wire array of 20 mm in outer diameter, and theK-shell yield of about 30 kJ for aluminum was measured. An X-ray energy fluence up to 732 J/cm2 was produced on an irradiated target which was positioned at 5 cm away from the X-ray source center. The irradiated target was an aluminum disk 2 mm in thickness and 10 mm in diameter, backed by an aluminum liner. The total weight of the disk and liner was 585 mg. An all-fiber photonic Doppler velocimeter (PDV) was used to monitor the motion of the rear surface of the irradiated target. The velocity history measured by PDV suggested a free-face velocity of 2.12 km/s when the shock wave arrived at the rear surface of the target, and the final velocity of the target is 180 m/s. Based on the Hugoniot relationships and the law of momentum conservation, a stress of the thermal shock wave of 19.2 GPa and a blowoff impulse per unit target area of 1341 Pa·s were deduced. Furthermore, a consequent coupling coefficient of 1.83 Pa·s·cm2/J was estimated from the measurements of blowoff impulse and the X-ray energy fluence. Finally, discussions on the reliability and uncertainty of the measurement were presented. These experimental results described here preliminarily validated the feasibility of the application of PDV to the research of X-ray thermomechanical effect.