Investigation of icosahedral quasicrystals by the kossel technique

X-ray Kossel patterns from icosahedral quasicrystals have been observed for the first time by exciting fluorescence radiation inside the i-Al 70 Pd 20 Mn 10 and i-Zn 50 Mg 45 Y 5 quasicrystals, using a 30 keV electron beam and white synchrotron radiation, respectively. The reflections detected allowed a determination of the lattice parameters and the crystal orientation. Some Kossel lines possess a light-dark or a dark-light fine structure, which depends on the intensity of absorption effects inside the crystal. This behaviour is due to dynamical X-ray diffraction.