RF Superconductivity for Particle Accelerators
Sergey Belomestnykh and Alexander Romanenko
Fermi National Accelerator Laboratory
Two-week course at USPAS 2017, Lisle, IL
June 12-23, 2017
Purpose and Audience
The two-week course will cover the science fundamentals and practical manufacturing, processing, and operational aspects of the superconducting RF cavities – the state-of-the-art technology used for both pulsed and CW particle acceleration. The course is intended to give a comprehensive introduction to the field for students, engineers, and physicists interested in entering this field, as well as to deepen understanding of the technology for those already exposed to some aspects of SRF.
Basic knowledge of electromagnetism, microwave techniques, and solid state/condensed matter physics at an undergraduate level.
Upon completion of the course students are expected to have a clear understanding of the advantages, basic underlying physics, open questions, and domain of applicability of SRF technology, as well as state-of-the-art infrastructure and techniques required for successful implementation of SRF-based accelerators.
The course will include lectures, computer lab, practical laboratory demonstrations, and instructional lab exercises performed at the extensive Fermilab SRF infrastructure. Homework problems will be assigned during the course, and a final exam at the end of the course will be given.
The course lectures will start from an introduction to the principles of RF acceleration and a general mathematical description of microwave cavities. The phenomenon of superconductivity, and the advantages it brings for RF cavities will then be discussed in detail. In-depth coverage of principles of RF superconductivity and various types of SRF cavities used for different applications will follow. Extrinsic phenomena adversely affecting the performance will be discussed including multipacting, field emission, hydrogen Q-disease. Modern cavity manufacturing, processing, and basic measurement techniques will then be reviewed. Key steps and challenges in engineering and operating of complete SRF cryomodules (cryostats, cavities, input couplers, higher order mode couplers and loads, frequency tuners) will be fully discussed. Beam-cavity interaction issues in operation will also be reviewed. Overview of the recent scientific progress and future outlook with standing challenges and promising research directions will conclude the course. Several practical exercises and demonstration for key topics will be integrated in the course. The practical exercises will utilize world-class SRF facilities at Fermilab.
Reading Requirements and Suggestions
The following textbook provided by USPAS will be extensively used during the course:
H. Padamsee, J. Knobloch, and T. Hays, RF Superconductivity for Accelerators, John Wiley and Sons, 2nd edition (2008)
It is recommended that students refresh their knowledge of the fundamentals of electrodynamics at the level of one of the following textbooks:
S. Ramo, J. R. Whinnery, and T. Van Duzer, Fields and Waves in Communication Electronics (Chapters 1 through 11), John Wiley & Sons, 3rd edition (1994)
J. D. Jackson, Classical Electrodynamics (Chapters 1 through 8), John Wiley & Sons, 3rd edition (1999)
R. E. Collins, Foundations for Microwave Engineering (Chapters 1 through 8), John Wiley & Sons (2001)
and their knowledge of condensed matter physics/superconductivity at the level of:
N. W. Ashcroft and N. D. Mermin, Solid State Physics (Chapter 34-Superconductivity), Cengage Learning (1976)
M. Tinkham, Introduction to superconductivity: second edition (Chapters 1-2), Dover Books on Physics (2004)
Additional suggested reference books:
Handbook of Accelerator Physics and Engineering, edited by A. W. Chao, K. H. Mess, M. Tigner and F. Zimmermann, World Scientific, 2nd Edition (2013)
H. Padamsee, RF Superconductivity: Science, Technology, and Applications, Wiley-VCH (2009).
Reference materials on wakefileds, wake potentials and beam loading:
"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).
Students will be evaluated based on the following performances: final exam (40%), homework assignments and class participation (35%) and lab exercises (25%).
Computer Lab and Codes
During the Computer Lab sessions students will be working on a project using computer codes ABCI and SUPERFISH. The codes will be installed on the USPAS computers. The other codes that will be available on the USPAS computers are: MATLAB, Microsoft Office.
Please keep in mind that commercial software (MATLAB, Microsoft Office) will not be available for installation on students' laptops due to licensing issues. Students will have to use USPAS computers to have access to these software packages if they do not have it. However, it will be sufficient to use LibreOffice or Google Docs instead.
ABCI code and documentation can be downloaded from the ABCI Home Page. It is available in Windows and Linux versions.
SUPERFISH can be downloaded from the LANL Accelerator Code Group Download Area for Poisson Superfish. It has only Windows version.
Computer Lab Project
Lecture Notes and Homework Problems
Monday, June 12
Lecture 1: Introduction: Advantages and limitations of SRF technology (S. Belomestnykh)
Lecture 2: Fundamentals of RF and microwave engineering (S. Belomestnykh)
Lecture 3: Basic concepts of RF superconductivity (A. Romanenko) - 2-hour lecture
Lecture 5: Cavity testing techniques (S. Belomestnykh)
Tuesday, June 13
Lecture 6: SRF systems: Requirements and challenges (S. Belomestnykh)
Computer Lab: Introduction
Derivation of the RF power formula for a beam loaded cavity can be found in RF_power_with_beam_loading.pdf
Wednesday, June 14
Lecture 9: Cavity design and optimization (A. Romanenko)
Lecture 10: Cryomodule design (S. Belomestnykh)
Lecture 11: Case study: LCLS-II (A. Romanenko)
Thursday, June 15
Friday, June 16
Hands-on experience day at Fermilab
RF measurements (M. Hassan and P. Berrutti)
Vertical cavity testing (A. Melnychuk and M. Checchin)
Monday, June 19
Tuesday, June 20
Lecture 15: Cavity fabrication and preparation techniques (A. Romanenko)
Lecture 16: Cryomodule production cycle (A. Romanenko)
Lecture 17: High-power RF systems (S. Belomestnykh)
Computer Lab - 2 hours
Wednesday, June 21
Hands-on experience day at Fermilab
Materials science (Y. Trenikhina and Z. Sung)
Clean room and chemical facilities (D. Bice, A. Rowe and C. Crawford)
Thursday, June 22
Lecture 18-19 (2 hours): Basic SRF science puzzles (A. Romanenko)
Final exam intro
Friday, June 23
Final exam Q&A
Lecture 20: Remaining challenges and outlook (S. Belomestnykh)
Students' feedback, general discussion