This specification discloses a measuring apparatus for measuring the wavefront aberration of an optical system for a soft X-ray which can highly accurately measure the wavefront aberration of the optical system without using the soft X-ray. This measuring apparatus has a light source for supplying light...http://www.google.de/patents/US7081962?utm_source=gb-gplus-sharePatent US7081962 - Aberration measuring apparatus for an optical system utilizing soft x-rays
