On the Influence of Electron Energy on Characteristics of the Cherenkov Radiation and Cathodoluminescence

Аннотация

A review of the results of investigations of the Cherenkov radiation (CR) and pulsed cathodoluminescence during irradiation of different crystals and polymethylmethacrylate (PMMA) with subnanosecond and nanosecond beams is made. The calculations demonstrating the influence of the electron energy and refractive index of a material on the CR intensity and spectrum, as well as its spatial characteristics are performed. The experimental data on the CR observation at the electron energy E up to 400 keV are presented. It is shown that an increase in E allows detecting the CR in diamond, leucosapphire, and quartz KU-1 crystals using a standard spectrometer. It is found out that is more difficult to register the CR in PMMA because of the radiation absorption in the region of wavelengths shorter than 300–350 nm and an internal breakdown of the specimens due to the accumulation of electrons in them at high beam current densities or (and) pulse durations, even with a monochromator and a PMT. Some recommendations are given for designing detectors of runaway electrons in tokomak-type facilities.