Design of Linear Electron Accelerators with Beam Loading

Abstract

The optimum design of linear electron accelerators depends upon the degree of beam loading, i.e., the fraction of the radio‐frequency power which is converted into beam power. With very light loading, the product of the radio‐frequency attenuation constant I, and the accelerator length L should be approximately 1.26 for maximum beam energy in a given length. For heavier loading the product IL must be reduced to produce maximum electron energy and maximum conversion efficiency from radio‐frequency power to electron beam power. The attenuation constant I can be chosen by the proper selection of the dimensions of the accelerating structure. Expressions and design curves are given for the optimum values of IL to maximize electron beam energy and electron beam power as a function of beam loading.