Beam Breakup Instability in Dielectric Structures

The single bunch-beam-breakup instability (BBU) is a potentially serious limitation on the performance of advanced accelerators, particularly those based on the wakefield principle. This project will develop mitigation techniques for BBU, using both experimental and high performance simulation tools. Three representative high performance wakefield devices will be studied experimentally at the Argonne Wakefield Accelerator using new diagnostics. An advanced simulation code to model these experiments will be developed. The combined results from the experiments and simulations will enable the design of focusing systems to control BBU in wakefield devices. Phase I will develop new software for rapid, efficient simulation of beam breakup effects in advanced linear accelerators. Simulations of beam breakup experiments (including a 26 GHz high power extractor, transformer ratio enhancement, and high gradient device experiments) will be performed. Two different beam diagnostics will be developed: a heterodyne differential probe and a beam spot moment diagnostic. Commercial Applications and other Benefits as described by the awardee: The tools should enable the design and operation of high performance wakefield accelerators, primarily for physics research, but also for industry and medical applications.