Observation of coherent Cherenkov radiation of electron bunches from a partially dielectric loaded waveguide

The results of experimental observation of coherent Cherenkov radiation from picosecond electron bunches traveling along the axis of a dielectric loaded cylindrical waveguide are presented. Experiments have been performed at the AREAL linear accelerator at the CANDLE Synchrotron Research Institute. The angular distribution of radiation from 3.7 MeV electron bunches passing through cylindrical quartz sample is investigated. In the second part of the paper we argue that, by tuning the ratio of the distance between the bunches crossing the plate inside the waveguide and the radius of the waveguide, one can further increase the intensity of quasicoherent Cherenkov radiation on several neighboring modes.