A Multiple-Cavity Linear Electron Accelerator

Abstract

A linear accelerator comprising 5 cylindrical cavities operating in the TM₀₁₀ mode on the divided power of a 10‐cm magnetron (nominally 1 megawatt) has produced electron beams up to 1.4 Mev. The first cavity is a phase buncher; the remaining ones, accelerators. Power is fed to the cavities through series tee connections to a master wave guide which is loaded with dielectric rods for adjusting the relative phases. The fields are of the order of 100 kilovolts per cm. The maximum output has been 0.25 microampere average, 5 percent of the injected current. The accelerated electrons consist of a high energy bunch containing 50 percent of the total output current, with the remainder of the electrons spread over the lower energies. The energy of the bunched component can be varied widely by changing the magnetron voltage and by operating with fewer cavities. This accelerator has proven a reliable research tool in a study of secondary electron emission of solids as a function of primary electron voltage over the range of 18 kilovolts to 1.4 Mev.