High resolution monochromatic synchrotron X-radiation diffraction imaging of triglycine sulfate (TGS) crystals

In order to shed light on the principal irregularities found in various optical crystals for infrared detectors, their origins, and their influence on device performance, we have carried out high resolution monochromatic synchrotron X-ray diffraction imaging of triglycine sulfate (TGS) crystals. Images of crystals grown during the First International Microgravity Laboratory (IML-1) flight in 1992 were taken and compared with others of terrestrially-grown crystals. The local acceptance angle for diffraction from the uncut TGS crystal grown on the IML-1 mission was found to be 1-2 arc seconds, indicating extraordinary crystal uniformity. The only inclusions visible in the topographs were polystyrene particles intentionally introduced into the growth solution of the space crystal. No demarcation was seen between the terrestrial seed and the new growth of the crystal grown in space. TGS crystals grown on the ground were found to have edge dislocations near the cleaved surface. The results of the topographic studies of the space- and ground-grown crystals are discussed and their implications identified.