INVESTIGATION OF ICOSAHEDRAL QUASI-CRYSTALS BY THE KOSSEL TECHNIQUE

X-ray Kossel patterns from icosahedral quasicrystals have been observe d for the first time by exciting fluorescence radiation inside the i-A l70Pd20Mn10 and i-Zn50Mg45Y5 quasicrystals, using a 30 keV electron be am and white synchrotron radiation, respectively, The reflections dete cted allowed a determination of the lattice parameters and the crystal orientation. Some Kossel lines possess a ''light-dark'' or a ''dark-l ight'' fine structure, which depends on the intensify of absorption ef fects inside the crystal. This behaviour is due to dynamical X-ray dif fraction.