Design of high-energy X-ray conversion target based on linear electron accelerator.

High-energy X-rays can be employed to inspect fuel elements, even weld seams, cracks, and internal structural deformations of the components due to their density-sensitive characteristics and strong penetration capabilities. The quality of these X-rays is determined by various factors such as the X-ray conversion target, the cooling system for the conversion target, and the filter type, thereby influencing the detection accuracy. This study was conducted using an electron linear accelerator with an energy of 10 MeV and an average current of 150 μA. Firstly, we designed the conversion target material and geometry structure by Monte Carlo method. The results indicate that the optimal target material is tungsten and the optimum shape of the conversion target is a cylinder with dimensions of Φ 40 × 2.2 mm. Second, finite element analysis was applied to design the conversion target cooling system. After 60 min of electron beam irradiation, the local maximum temperature of the conversion target is approximately 1330 °C. Lastly, theoretical analysis and Monte Carlo simulations were used to design the X-ray filters. The result demonstrates that a double-layer filter consisting of 8 mm bismuth and 4 mm iron can increase the proportion of high-energy X-rays by 13.89 ± 0.05 %. Finally, the results of using the attenuation method to measure the X-ray energy spectrum produced by an electron linear accelerator indicate that without a filter 78.81 % of the X-rays are above 1 MeV and with a filter this proportion increases to 80.55 %.