Number 262 (Story #2), March 14, 1996 by Phillip F. Schewe and Ben Stein THE FIRST X-RAY HOLOGRAM WITH ATOMIC RESOLUTION has been made by scientists at the Research Institute for Solid State Physics in Budapest, Hungary. They sent a beam of 17-keV x rays into a perovskite crystal (SrTiO3). Some of the x rays strike strontium atoms, where they eject inner-core electrons. Filling this vacancy results in the emission of 14-keV "fluorescence" x rays. Part of this x-ray wave scatters from other atoms, while part emerges unscattered. The interference of the two waves can be monitored in a solid-state detector at many angles. The ensuing hologram provides a direct three-dimensional image of the strontium atoms in the crystal. In effect, the use of such an atomic localized source of x rays is less ambiguous in determining the internal structure of the solid than are conventional x-ray diffraction techniques. (Miklos Tegze and Gyula Faigel, Nature, 7 March 1996.)