Optimization of dynamically bent crystals for X-ray focusing monochromators

It is well known that one can use a sagittally bent second crystal in order to increase horizontal angular acceptance of a double crystal monochromato r. A dynamically bent second crystal in such a monochromator with 6 mrad ho rizontal acceptance has been studied and the anticlastic distortions were c alculated by means of finite element modeling. It was decided that in order to decrease the undesirable bending of the crystal in the meridional direc tion, stiffening ribs would be cut on its non-working surface. The design o f the second monochromator crystal was optimized with respect to the calcul ated performance and also to the crystal manufacturing process. The optimum design was found to be a crystal with seven stiffening ribs on its non-wor king surface, which was duly manufactured. (C) 2001 Elsevier Science B.V. A ll rights reserved.