SEMINAR       Wednesday, December 10th 2003 - h. 15:00  Aula Touschek     N.F. Shul'ga (ITP NSC KhIPT, Kharkov)        "Mechanisms of scattering and radiation by electrons and positrons with energy of the order of some hundred MeV in oriented crystals"           Abstract - Coherent radiation (CB) and channeling radiation (CR): history, validity conditions... - The motion of relativistic electrons and positrons in periodical field of crystal atomic strings, dynamical chaos phenomenon at channeling and scattering of the particles in crystal, Levy flights in crystal. - Influence of the motion types on coherent radiation (CB at dynamical chaos conditions, ...), X-ray coherent radiation, simulation of spectrum and polarization of coherent radiation, radiation by relativistic electrons and positrons in oriented crystals, theory and Kharkov experiment for 1 GeV electron energy, new experiment proposals on CB and CR at Frascati. Additional questions (if it will be interesting): - Parametric X-ray in crystal (line width for electrons and positrons). - Radiation in pre-wave zone, influence of transfer target size on tranition radiation. - Coherent radiation at collisions of short bunches of relativistic particles.