Development of field emitter non-adiabatic electron optic system for the spectroscopic 263 GHz/CW gyrotronV.N. Manuilov, G.G. Sominskii, E.P. Taradaev, T.A. Tumareva and M.Yu. GlyavinEPJ Web Conf., 149 (2017) 04036DOI: https://doi.org/10.1051/epjconf/201714904036