Patent Number: 051630788
Section: claims

1. A multilayer film reflecting mirror comprising layers of a plurality of substances constructed on a substrate, suited for X rays having wavelengths of 100 .ANG. and less, wherein a deviation .DELTA. from a standard value of thickness of each layer is within a range defined by ##EQU11## where .theta. is the grazing angle of an X ray incident on the reflecting mirror and .lambda. is the wavelength of the X ray. 2. The reflecting mirror according to claim 1, wherein said plurality of substances is comprised of Ni and Sc, and said layers are alternately laminated on the substrate so that a multilayer film is fabricated. 3. The reflecting mirror according to claim 1, wherein said plurality of substances is comprised of Re and Al, and said layers are alternately laminated on the substrate so that a multilayer film is fabricated. 4. The reflecting mirror according to claim 1, wherein said plurality of substances is comprised of W and C, and said layers are alternately laminated on the substrate so that a multilayer film is fabricated. 5. The reflecting mirror according to claim 1, wherein at least one of said plurality of substances is comprised of Ni, and said layers are alternately laminated on the substrate so that a multilayer film is fabricated. 6. The reflecting mirror according to claim 1, wherein said substrate has a curvature. 7. The reflecting mirror according to claim 1, wherein said reflecting mirror constitutes a Schwarzschild optical system. 8. The reflecting mirror according to claim 1, wherein said reflecting mirror constitutes a Walter optical system.