Computer Program for a High-Current Electron Accelerator

Abstract

A comprehensive computer program for a high-current accelerator operating in the 100 ampere/ 10 MeV range has been developed. The accelerator is a narrow-bandwidth, coupled-cavity device with or without feedback between input and output cavities. Equations for the transient behavior of both the pumped or buildup pnase and the accelerator phase have been programmed to allow for a wide range of design parameters such as number of cavities, cavity-cavity coupling, beam-cavity coupling, cavity loss or Q, stagger tuned cavities, input-output cavity coupling, and injected current as a function of timne. The sinusoidal electric field in each cavity is expanded with the resonant modes, excited by the beam and boundary-matching magnetic current on the center holes. The irrotational field is computed as the unretarded Coulomb field of the beam as a collection of discs and their images. Feedback and feedforward waves in a waveguide which couples input and output cavities are represented by cutoff and propagating waveguide modes decomposed into Fourier components. Some computational properties of the program are discussed.