高能X射线聚焦组合透镜的理论研究

Theory of the Compound X-Ray Lenses for Focusing High Energy X-Ray Radiation

X射线聚焦组合透镜是一种利用折射效应对X射线辐射聚焦的新型元件。针对X射线波段的特性 ,综合考虑折射和吸收效应得出组合透镜的衍射屏函数 ,并利用衍射理论推导出X射线组合透镜的设计理论。利用统计学理论中一阶、二阶原点矩表征像面处的光学性能 ,使设计更简洁。该理论方法可方便地推广到双凹折射单元情况。通过数值计算分析了像面处强度分布的二阶中心矩以及焦点处辐射强度随组合透镜结构参量的变化关系 ,给出了一种铝基X射线组合透镜的结构参量设计结果。对于设计的组合透镜结构参量 ,计算了当X射线辐射能量分别为 0 .93keV ,9.89keV和 2 9.78keV时 。

The X-ray compound lens is a novel optical device that focuses X-ray radiation by refraction effect. The theoretical and numerical study of such a device is reported, including the derivations of the diffractive screen function of the compound lens and the equations of the intensity distribution in the focus plane by considering both refraction and absorption effect and diffraction theory. The first-order and the second-order origin moments are used to describe the optical performances of the device at the image plane. This theoretical method can be easily generalized to the case of the compound X-ray lens with a double-concave shape. The structural parameters of an X-ray compound lens with Al material are designed. The second-order central moment of the intensity distribution at the image plane and dependence of the radiation intensity at the focus on the structural parameters of the compound lens are analyzed by using numerical calculationm at the focal plane after X-ray radiation passes the compound lens is calculated as X-ray raidation energy is 0.93 keV, 9.89 keV and 29.78 keV, respectively.