A back-reflection Laue camera with three rotation axes and three orthogonal translation axes is described. This camera allows the alignment of large single crystals with a precision of plus or minus 0.25 deg . The degree of single crystallinity of a specimen may be examined. In addition it is possible to accurately mark a crystal for subsequent utilization. (auth)

Techniques are described for obtaining x ray diffraction information on active metals at high temperatures. One method is used to 1000 deg C with rare earths; the other method is used to 2200 deg C with tungsten, and to 1400 deg C with some f the higher melting rare earths. The latter approach permits simultaneous measurement of resistance of the specimens vs temperature and the diffraction pattern, which facilitates the characterizing of the high temperature forms of the metals. (auth)