This reliable and well proven sagittal bender is recommended for use with the standard FMB Oxford double crystal monochromator. The system was co-designed in the optics group of the ESRF and at the CNRS Laboratoire de Cristallographie, Grenoble, and is based on the principle of flexure hinges which accurately guide the thin, ribbed crystal to form a cylindrical diffraction surface, minimising twist and anticlastic bend.

We offer two enhancements to the basic design. Firstly, the minimum bend radius can be lowered to less than 1.8m (the crystal can bend down to 1.2m before there is a danger of brittle fracture) if gearboxes are fitted to the motors to allow a greater force to be applied to the flexure hinges. Secondly, using Linear Variable Differential Transformer non-contact, high resolution encoders, it is possible to obtain a measure of the degree of bending outside the optical hutch.