U.S. Particle Accelerator School

Microwave Sources course

Sponsoring University:

College of William and Mary


Microwave Sources


Bruce Carlsten and Steve Russell, LANL

This course will be taught at a level suitable for a first-year graduate student. The purpose of this course will be to provide a solid foundation for understanding how common microwave devices work, particularly those associated with driving accelerators, and how to predict device gain and efficiency. Three general topics will be covered - (1) beam physics relevant for microwave tubes, (2) standing-wave amplifiers, and (3) traveling-wave amplifiers. The beam physics material will include topics on magnetic focusing and space-charge forces, such as Busch's Theorem, solenoidal and PPM focusing, diamagnetic effects, potential depression, space-charge waves, balanced flow, confined flow, and Brillioun flow. A paraxial optical theory for halo description will be given, and stable sheet beam transport will be included in these discussions. A detailed analysis of how a klystron works will be used as an example of a standing-wave amplifier. A beam/cavity interaction model based on induced current will be presented. Students will have an opportunity to write a simplified klystron simulation code (neglecting space-charge effects) in the computer lab. A Pierce-type traveling-wave tube analysis will be presented, which will be used to describe a common helix traveling-wave tube, a sheet beam traveling-wave tube, and a dielectric Cherenkov maser, and a free-electron laser. Selected unconventional sources and non-accelerator applications will be surveyed. Prerequisites: a course in Electromagnetism and Calculus.