Thin X ray Lens Design And Simulation

A proposal of thin sandwich mirror array lens for X-ray telescope Wolter type lens is discussed. We discussed a process of design, fabrication of this thin X-ray lens and conducted a simulation and provided a measurement method for lens focal quality. The lens consists of two connected layers of arrays of rings of mirrors, one is of parabolic mirror and another is of hyperbolic mirrors. In each layer, the mirror coating is deposited on a substrate and next substrate in turn is deposited on this mirror film, leaving no air gap. Repeat this process to form an array of mirrors. Hence form a solid thin disc sandwich mirror lens and each ring of mirror can be curved precisely by polishing process. X ray travels into the transparent substrate and grazes on the surface of the mirror coating facing the substrate. Using geometrical optics ray tracing, we conducted simulation with two artificial distance stars as the source objects, a virtual lens of mirror array and a disc placed at the focal plane as the receiver CCD. Simulation shows that the star located off optical axis forms corn shape patterns by its ray crossing pointa on CCD disc. Those patterns may provide the baseline pattern for further image deconvolution or aberration reducing algorithm. The corn pattern is related to the dimensional structure of the lens and the space location of the star; hence, it contains some information about space location of the star. A simulation of ray tracing video is made as well. The thin sandwich lens we discussed in this paper may provide a way to build a large aperture telescope X ray lens