用于高能微焦点工业CT的旋转式辐射转换靶研究  

Research on Rotatable Radiation Conversion Target Used in High-energy Microfocus Industrial CT

作　　者：刘宇[1] 肖德鑫[1] 李鹏[1] 周征 周奎[1] 单李军[1] 张鹏[1] 沈旭明[1] 胡栋材[1] 王建新[1] 吴岱[1] 杨兴繁[1] 黎明[1] 金晓[1] LIU Yu;XIAO Dexin;LI Peng;ZHOU Zheng;ZHOU Kui;SHAN Lijun;ZHANG Peng;SHEN Xuming;HU Dongcai;WANG Jianxin;WU Dai;YANG Xingfan;LI Ming;JIN Xiao(Institute of Applied Electronics,China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]中国工程物理研究院应用电子学研究所,四川绵阳621900

出　　处：《原子能科学技术》2022年第7期1465-1472,共8页Atomic Energy Science and Technology

摘　　要：转换效率高、散热性能优异的辐射转换靶是高能微焦点工业CT的关键部件,本文设计了一种适用于高能(6 MeV)微焦点(直径约100μm)工业CT的先进旋转式辐射转换靶。通过模拟分析辐射转换靶X射线转换效率和热沉积,确定最优转换靶厚度,从而设计、加工出旋转式辐射转化靶,并成功应用于中国工程物理研究院应用电子学研究所高能微焦点工业CT验证装置。对比实验结果显示,在相同工况(电子束能量6 MeV,宏脉冲长度5 ms,宏脉冲流强1.5 mA,焦斑直径100μm)下,固定靶被电子束熔融,而旋转靶则能够承受电子束的轰击,验证了旋转式辐射转换靶的有效性和可靠性。The radiation conversion target with high conversion efficiency and excellent heat dissipation performance is the key component of high-energy microfocus industrial CT.In order to produce high-flux,microfocus X-rays via bremsstrahlung,very high beam power will be deposited in a small area on this conversion target.For the static conversion target used in the common industrial CT,there is a great chance that this target will be melted under the hitting of high energy and high average current beams.Therefore,an advanced rotatable radiation conversion target suitable for high-energy(6 MeV)microfocus(with diameter of 100μm)industrial CT was designed to settle this bottleneck problem in this paper.By simulating and analyzing the X-ray conversion efficiency and residual electron beam energy,the optimal thickness of the conversion target was determined,which is 3 mm.Further thermal analysis shows that,under the operation condition of electron beams(with electron beam energy of 6 MeV,macro pulse length of 5 ms,macro pulse current of 1.5 mA and focal spot diameter of 100μm),static target will be melted after few macro pulses.Using a rotatable radiation conversion target with 2000 r/min,the transient temperature rise is only 137°for one macro pulse,and the steady state temperature is 197°,which is much lower than the melting point of tungsten material.Based on these simulation results,a rotatable radiation conversion target was designed and fabricated.In addition,a special design of in-situ ultra-small beam size measurement system was realized in this conversion target system,which is mainly composed of a retractable ultra-thin YAG screen and a 45°reflecting mirror.Finally,the rotatable radiation conversion target was successfully installed and applied to the high-energy microfocus industry CT verification device of the Institute of Applied Electronics,China Academy of Engineering Physics.In beam experiment,the rotating target can indeed withstand the bombardment of the electron beam under operation condition of elect

关 键 词：高能微焦点工业CT 辐射转化效率分析 热沉积分析 原位测量 辐射转换靶 

分 类 号：TL503.92[核科学技术—核技术及应用]