INTENSE ELECTRON-BEAM PROPAGATION IN A DIELECTRIC GUIDE

Intense electron-beam propagation in a dielectric guide, without external magnetic fields, has been studied for 30-100-keV beams with ν/γ≃1. The electron beam was injected into an evacuated cavity lined by dielectric materials with a thickness exceeding the electron range. The beam did not propagate until it was charge neutralized by ions removed from the dielectric following surface flashover caused by electron bombardment. The charge transported was a linear function of the cylindrical guide length, and the beam could be focused by a conical guide. Transport efficiency was reduced for dielectrics made of SiO2 compared to various plastics.