Corrective optics for diffraction of γ-rays

A new method to correct imperfect bending of curved crystals used for γ-ray diffraction spectroscopy is presented. It relies on using position-sensitive segmented Ge-detectors and permits the determination of the emission area of each γ-ray from the crystals and therefore an off-line correction of bending imperfections as if the crystals were divided into independent 2×2 mm2 bent crystals. A first experiment using the GAMS-5 spectrometer (Institut Laue-Langevin) shows proof of the principle of the method.