Experimental shape optimization of bent crystals

We report on first results obtained with a novel, x-ray- based method that permits to correct residual slope errors of curved crystals to (mu) rad accuracy. It consists of two steps. The first is to measure the slope error very precisely, the second to shape the sides of the crystal plate to be bent according to the correction calculated from simple bending theory and thus to achieve a substantial improvement of the lattice plane slope error. The same technique can be applied to elastically bent mirrors or multilayers.