Determination of the optical quality of a fluoride monocrystal by irradiating a volume element with hard X-rays following a given family of crystalline planes

摘要

Determination of the optical quality of a fluoride monocrystal comprises: (a) irradiation of at least one volume element of the monocrystal, following at least one family of crystalline planes by a beam of hard X-rays to obtain a diffraction image in transmission mode of the X-rays crossing the volume element along the family of crystalline planes; (b) studying the image produced; (c) calculating the mosaicity of the volume element along the family of crystalline planes from this study. An Independent claim is also included for an optical element for utilization in projection systems operating at wavelengths of between 100 and 200 nm using a fluoride monocrystal with a mosaicity of less than 10 s.