Tolerance analysis on nested conical Wolter-I X-ray telescope

The degradation of image quality of the nested conical Wolter-I X-ray telescope mainly results from mirror-position tolerance, alignment-bar tolerance and surface-figure tolerance. The analytical approach of the three kinds of tolerance was presented in this paper. Based on the predetermined initial structure, we analyzed and compared image qualities with different tolerances. Furthermore, we simulated the distribution of the spot diagrams and calculated the spatial resolution of the entire system. Shift along the optical axis (Z axis) and rotation around it have no effects on the image quality for position tolerances. However, shift along X, Y directions and rotation around X, Y axes change the distribution of spot diagrams and decrease the spatial resolution. For higher resolution, we should control the alignment-bar tolerance by placing a displacement sensor at the end of the alignment bar. The angular resolution increases from 1' to 13 '' as the alignment-bar tolerance decreased from +/- 15um to +/- 3um. With respect to surface-figure tolerance, we simulated image qualities by inserting Zernike polynomial to the surface.