Optimization of a Wolter type I mirror for a soft X-ray microscope

The demand for an X-ray microscope has received much attention because of the desire to study living cells under high resolution. A Wolter type I mirror used for soft X-ray microscope optics has a number of advantages. Although much progress has been made, it is still not easy to fabricate this mirror and satisfy the surface roughness and figure error requirements. From the mirror fabrication point of view, it is necessary to see the mirror design and the tolerance budget, especially with respect to the surface roughness and the figure errors. This paper deals with the design and optimization of a Wolter type I microscope mirror. The optimization was carried out by choosing an optimum central grazing incidence angle for which a merit function had the maximum value. The image quality of the mirror was also examined. A smaller diameter gave better image quality because of the Abbe sine condition. Finally, the figure errors for the axial and the radial directions were simulated by sinusoidal deformation waves, and the figure tolerance was obtained.