Bent crystals as high-reflectivity components for a Laue lens: Basic concepts and experimental techniques

For fabrication of crystals with curved diffracting planes, several techniques have been worked out. Amongst curved crystals, special interest is given to those that are being bent due to internal forces. Surface grooving is proposed as an efficient method to reproducibly obtain self-standing bent crystals. Silicon or germanium plates can be plastically deformed by grooving one of their major surfaces with very good control of the curvature. We present a systematic experimental study and a model based on the theory of elasticity. The technique enables the fabrication, in a very reproducible fashion, of curved crystals for the realization of an high-efficiency hard X-ray concentrator (Laue lens). © 2012 SPIE.