X-RAY LUMINESCENT COMPOSITES BASED ON POLYCRYSTALLINE DIAMOND WITH INTEGRATED NAGDF4:EU NANOPARTICLES FOR PHOTONICS by Sergey V. Kuznetsov, Vadim S. Sedov, Artem K. Martyanov, Vera Yu. Proydakova, Viktor G. Ralchenko, Sergey Kh. Batygov, Valeriy V. Voronov, Alexey D. Yapryntsev, Vladimir K. Ivanov, Pavel P. Fedorov