Dr Sergey Uglov (Tomsk Polytechnic University)
The dynamics of changing the form of angular distribution and intensity of EUV radiation emitted from a multilayer Mo/Si mirror with changing the angle of grazing incidence o of 5.7 MeV electrons on the mirror surface has been investigated. Two series of angular distributions of radiation have been measured in the region of detection angle 60o< D <160o with and without use a 1 μm Al absorption filter. The Mo/Si mirror consisted of 50 Mo/Si bi-layers with the thicknesses of 11.32 nm was used in the experiment. The measured results have shown that the maximum intensity of EUV radiation in the angular distributions measured without the Al filter decreases at increase of the angle o, while the similar characteristic measured with the Al filter increases. Comparison of the observed tendencies of changing the maximum intensity of the angular distributions of EUV radiation with the results of model calculations of a back transition radiation  and diffracted transition radiation  has shown that in the experiment the contribution of narrow-directed quasimonochromatic component in the spectrum of radiation emitted in the Bragg direction has been observed. Earlier, the observation of such type of EUV radiation was carried out on the base of simple comparison of the intensities of radiations generated in a homogeneous target and a multilayer mirror . The demonstration of existence of quasimonochromatic EUV component in radiation generated in multilayer mirror carried out in this work is more reliable because the used approach is based on the analysis of behavior of the spectral-angular characteristics of radiation that is specific namely for coherent radiation generated by charged particles in periodic structures . This work was partially supported by the Russian Ministry of Education and Science program ``Nauka'', Grant 2456, and by the Russian Foundation for Basic Research, Grant 14-02-01032. References 1. V.E. Pafomov, 1971 Proceedings of the P.N. Lebedev Physics Institute 44, ed. by D.V. Skolbel'tsyn (New York: Consultants Bureau) 25. здесь год есть? 2. N.N. Nasonov, V.V. Kaplin, S.R. Uglov, M. Piestrup, C. Gary, Phys. Rev. E 68 (2003) 036504. 3. S.R. Uglov, V.V. Kaplin, et al., Jour. of Phys.: Conf. Ser. 517 (2014) 012009. 4. Ter-Mikaelian M.L. Y. High-Energy Electromagnetic Processes in Condensed Media, Wiley-Interscience, New York, 1972.