INVESTIGATION OF THE PRODUCTION MECHANISM OF PARAMETRIC X-RAY-RADIATION

Parametric x-ray Radiation (PXR) in the energy range from 5 to 20 keV produced by 855 MeV electrons using a single Si crystal was studied at the Mainz Microtron MAMI. The production mechanism was investigated b y measuring the angular distributions for several orders of PXR and it s dependence from the crystal thickness. A silicon crystal shaped in s teps with thicknesses ranging from 100 mu m to 600 mu m was used. The experiments were carried out using LN2-cooled PIN photodiodes with an energy resolution of 950 eV. The absolute photon flux was measured for the (111)-, (220)- and (224)-reflection planes and are in very good a greement with a kinematical model. The angular distributions are well reproduced by an ansatz, which incoherently adds to the PXR a portion of diffracted bremsstrahlung and diffracted transition radiation.