Control of energy sweep and transverse beam motion in induction linacs

Recent data and the advances that have made improved beam quality possible are discussed. The most important advances are: understanding of focusing magnetic field errors and improvements in alignment of the magnetic axis, a redesign of the high-voltage pulse distribution system between the magnetic compression modulators and the accelerator cells, and exploitation of a beam tuning algorithm for minimizing transverse beam motion. A brief description is also given of the prospects for increasing the pulse repetition frequency to the range of 5 kHz and a delayed feedback method of regulating beam energy over very long pulse bursts, thus making average power megawatt-level microwave sources at 140 GHz and above a possibility.<>