Researches On KBA X-ray Microscope

In the latest years, x-ray imaging technology has developed fast in order to meet the need of x-ray photo-etching, spatial exploration technology, high-energy physics, procedure diagnosis of inertial confinement fusion (ICF) etc. Since refractive index of materials in the x-ray region is lower than 1, and x-ray is strongly absorbed by the materials, it is very difficult to image objects in the x-ray region. Conventional imaging methods are hardly suitable to x-ray range. Generally, grazing reflective imaging and coding aperture imaging methods have been adopted more and more. In this article, the non-coaxial KBA x-ray microscope working at grazing incidence is discussed in detail. In view of the special structure of KBA microscope, we have compiled an optical computing program for the system. Using this program, we trace a large number of rays. From the point of view of optical design, we make analysis of the structure, aberrations, imaging quality and tolerance of KBA microscope. We provide a large number of computation data of KBA microscope, and these data are the basis for machining and mounting KBA microscope. In this paper, main works are as follow: (1) Analysis of KBA microscope structure. Focal length, imaging and reflecting characteristics of KBA microscope are studied. Rationality of KBA structure is analyzed, and program for it is compiled. (2) Analysis of KBA aberrations. Astigmatism, field obliquity, spherical aberration and coma are analyzed using the progam to trace numerous rays. The results show that KBA is anastigmatic and field obliquity becomes severe with field altering larger in image space. Since there are no variations for correctiong aberrations, sperical aberration and coma still exist. However comparing to KB, aberrations are reduced greatly. (3) Analysis of KBA microscope imaging quality. The results of complete evaluation and analysis of imaging useing spot diagram, encircled energy and MTF illustrate that this system conforms to the requirements, and satisfies the resolution of the need. (4) Analysis of KBA microscope parameters error. Changing of system parameters such as mirror radius, angle between bimirror, grazing incident angle affect gauss parameters and aberrations (such as imaging distance, astigmatism, blur diagram, multiple and MTF). The alterings of these parameters reduce imaging quality. Fabrication and assembly tolerances are made according to the allowed quality reduction of the user. (5) Analysis of KBA reflectivity. Within soft x-ray range, through calculation KBA microscope reflectivity of two selective fabrication methods, the effect of roughness on reflectivity at grzing incedent is analyzed. It can be the theoretical dependence of KBA fabricaton. Analysis shows that KBA microscope is an...