Influence of the Orientation of the Metal-Ceramic Plates on the Distribution of the Beam Current Density at the Anode

Abstract

In technological applications of electron accelerators, the homogeneity of the electron beams current density distribution on the anode is of great importance, since it determines the non-uniformity of the absorbed dose distribution on the irradiated product. For URT-type accelerators, metal-ceramic (MC) cathodes have been developed that have a sufficiently high homogeneity of the electron beam current density distribution on the anode (inhomogeneity <10%). The aim of this work was to study the influence of the MC plate arrangement direction in the cathode holder (along and across), as well as the distance of the MC plate extension beyond the screen cut on the electron beam current density distribution on the anode. The studies were carried out on the URT-1M accelerator with a 420 mm wide cathode with 4 MC plates. During the experiments, the beam current and accelerating voltage (channel resolution <7 ns) and the electron beam current density distribution on the anode were measured using the luminescence method. The experimental results showed that by changing the MC plate arrangement direction and the distance of the MC plate extension beyond the screen cut, it is possible to control not only the shape of the electron beam current density distribution on the anode, but also its amplitude.