基于单次全反射椭球单玻璃管X射线聚焦镜表征光源参数

摘要

为了正确表征X射线光源参数,本文利用单次全反射椭球单玻璃管X射线聚焦镜,设计了一种测量X射线光源焦斑尺寸和焦深的方法.该方法利用椭球单玻璃管X射线聚焦镜具有单次全反射成像能力的特点,对多个已知焦斑尺寸的多毛细管X光透镜模拟光源的焦斑成像尺寸和椭球聚焦镜的面形误差进行表征,从而确定光源焦斑尺寸和经过椭球聚焦镜后的焦斑成像尺寸以及椭球聚焦镜的面型误差之间的通用数学关系.然后,通过分析待测光源焦斑经过椭球聚焦镜所成像的尺寸来得到被测量光源的焦斑尺寸.利用该法也同样可以得到光源焦深的大小.为了验证设计方法的可行性,测量了实验室微焦斑X射线光源的焦斑和焦深参数.测试显示:对于焦斑直径约为50μm、焦深约为20 m m的光源,文中方法得到的算术平均值标准偏差分别为1.5μm和0.7mm.结果表明:本文设计的光源参数表征方法可以实现对微焦斑源焦斑尺寸和焦深的同时测量,在X射线源的研制和应用领域具有潜在应用.%To exactly characterize X-ray light resource parameters ,a measuring method for the focal spot size and focal depth of an X-ray source was proposed by using a single-bounce ellipsoidal monocapillary X-ray condenser (SBEMXRC) .The SBEMXRC was a kind of X-ray reflective imaging optics and characterized by its single total reflection imaging capability .The universal relationship among the focal spot size of the X-ray source ,image size of focal spot of the X-ray source and the slope errors of the SBEMXRC was determined by the X-ray sources with known spot sizes simulated by a polycapillary X-ray lens . The focal spot size of the X-ray source with a unknown spot size was accordingly obtained by analyzing image size of the focal spot .The focal depth of the X-ray source could also be measured by the designed method .To verify the feasibility of the designed method ,the spot size and the focal depth of a microfocus X-ray source in our lab were measured .The experimental results show that the arithmetic mean standard deviations of the measurement are 1 .5μm and 0 .7 mm for the X-ray source with a spot size about 50 μm and a focal depth about 20 mm ,respectively .The results demonstrate that the focal spot size and focal depth of the X-ray source could be simultaneously measured with the designed method . This method has potential applications in the field of X-ray sources .