U.S. Particle Accelerator School

Course Materials - University of New Mexico - June 2009

Superconducting RF for Storage Rings, ERLs and Linac-Based FELs

S. Belomestnykh (Cornell University)
Teaching Assistant: D. Meidlinger (Cornell University)

Purpose and Audience
This graduate level course covers application of superconducting radio frequency (SRF) technology to contemporary electron accelerators: storage rings, energy recovery linacs (ERLs) and linac-based free electron lasers (FELs). The course will address physics and engineering aspects of using SRF in accelerators. It will cover beam-cavity interactions issues specific to superconducting cavities, a systems approach to designing SRF systems and engineering of superconducting cavity cryomodules. The course is intended for graduate students pursuing accelerator physics and graduate engineers and physicists who want to familiarize themselves with superconducting RF systems.

Prerequisites
Classical mechanics, thermodynamics, electrodynamics, and physical or engineering mathematics, all at entrance graduate level.

Objectives
Upon completion of this course, the students are expected to understand the physics underlying RF superconductivity and its application to accelerators, the advantages and limitations of SRF technology. The aim is to provide students with ideas and approaches enabling them to evaluate and solve problems related to application of superconducting cavities to accelerators, as well actively participate in engineering of SRF systems for various accelerators.

Instruction Method
This course includes a series of lectures and exercise sessions. Homework problems will be assigned which will be graded and answers provided in the exercise sessions. There will be an open-book, "take-home" final exam at the conclusion of the course.

Course Content
The course will include a brief introduction of the basic concepts of microwave cavities and the basic concepts of RF superconductivity. The main body of the course will consist of two parts. The first part will cover the beam-cavity interaction issues: wake fields and higher-order modes (HOMs) in superconducting structures, associated with them bunched beam instabilities and approaches to deal with these instabilities (HOM absorbers and couplers, polarized cavities, etc.), bunch length manipulation with SRF cavities, beam loading effects, etc. In the second part we will discuss a systems approach and its application to engineering of SRF systems for accelerators including design of cryostats, cavities and auxiliary components such as input couplers, HOM loads, and frequency tuners.

Reading Requirements
"RF Superconductivity for Accelerators", by H. Padamsee, J. Knobloch, and T. Hays, John Wiley & Sons, 2nd edition (2008) (to be provided by USPAS).

It is recommended that students re-familiarize themselves with the fundamentals of electrodynamics at the level of "Fields and Waves in Communication Electronics" (Chapters 1 through 11) by S. Ramo, J. R. Whinnery, and T. Van Duzer, John Wiley & Sons, 3rd edition (1994) or "Classical Electrodynamics" (Chapters 1 through 8) by J. D. Jackson, John Wiley & Sons, 3rd edition (1999).

Additional suggested references (not provided):

"Handbook of Accelerator Physics and Engineering", edited by A. W. Chao and M. Tigner, World Scientific, 3rd print (2006).

"Introduction to Wakefields and Wake Potentials" by P. B. Wilson, SLAC-PUB-4547 (1989).

"High Energy Electron Linacs: Application to Storage Ring RF Systems and Linear Colliders" by P. B. Wilson, SLAC-PUB-2884 (1982).

"Fundamental-Mode RF Design in e+e- Storage Ring Factories" by P. B. Wilson, SLAC-PUB-6062 (1993).

Homework problems and solutions:

Monday

Tuesday

Wednesday

Thursday

Friday

Final Exam