Multipactor in Accelerating Cavities

This book is written by two world-recognized experts in radio frequency (RF) systems for particle accelerators and is based on many years of experience in dealing with the multipactor phenomenon. The authors introduce and review multipactor in RF cavities for scientists and engineers working in the field of accelerator physics and technology. The multipactor phenomenon of unintended electron avalanches occurs in the RF cavities commonly and quite often is a performance-limiting factor. The book starts with an Introductory Overview which contains historical observations and brief description of most common aspects of the phenomenon. Part I deals with the multipactor in a flat gap. It starts with description of the dynamics of electrons, derivation of the stability condition and analyzing influence of several factors on the multipactor. Then, the initial considerations are extended to derive a generalized phase stability and finally a particular case, called ping-pong multipacting, is considered. The part one is concluded with a brief review of computer codes used in multipactor simulations. Part II is dedicated to the multipactor in crossed RF fields, the typical situation in accelerating cavities. Two cases of MP are considered: a two-point multipactor near the cavity equator in elliptical cavities and a one-point multipactor. Part III describes optimization of the cavity shapes geared toward designing multipactor-free structures. The book will serve as an importance reference on multipactor for those involved in developing and operating radio frequency cavities for particle accelerators.

Offers a comprehensive description of multipactor in accelerating cavities for scientists and engineers Provides theoretical treatment of the phenomenon, ties it up with experimental results, and provides insights on developing multipactor-free accelerating cavities Includes historical overview of advances in understanding multipactor

Auteur

Dr. Valery Shemelin received his M.S. degree from Novosibirsk State Technical University and his Ph.D. degree from Budker Institute of Nuclear Physics (Novosibirsk, Russia) where he worked for many years on accelerator projects. Dr. Shemelin joined Cornell University's Laboratory for Elementary Particle Physics in 2000 where he stayed until retirement in 2014. His research interests are concentrated mainly around designing accelerating structures and cavities, optimization of their geometries, studying multipactor discharge, along with simulations and measurements of RF properties of various material at room and cryogenic temperatures. In particular, he made significant contributions to developing superconducting radio frequency cavities and higher order mode absorbers for Energy Recovery Linac (ERL) project at Cornell.
Dr. Sergey Belomestnykh is a Senior Scientist, Chief Technology Officer and Head of Applied Physics and Superconducting Technology Division at Fermi National Accelerator Laboratory (Fermilab). He received his M.S. degree from Novosibirsk State Technical University and his Ph.D. degree from Budker Institute of Nuclear Physics (Novosibirsk, Russia) where he worked for many years and was involved in several accelerator projects developing radio frequency (RF) systems. He joined Cornell University's Laboratory for Elementary Particle Physics in 1994, working on developing superconducting RF (SRF) systems for Cornell Electron Storage Ring (CESR) and Cornell ERL as a CESR RF group leader. In 2010, he joined Brookhaven National Laboratory. In his capacity as a Scientists and Superconducting RF group leader, Dr. Belomestnykh led development of SRF and RF systems for several projects. Since 2015, he is with Fermilab overseeing research and operations of a large Division and coordination technology development throughout the laboratory. He is an Adjunct Professor at the Department of Physics and Astronomy, Stony Brook University. Dr. Belomestnykh is a Fellow of the American Physical Society and a recipient of the 2015 IEEE NPSS Particle Accelerator Science and Technology Award "for achievements in the science and technology of RF and SRF for particle accelerators.

Contenu
Part 1. Multipactor in a planar gap.- Chapter 1. Existence zones for multipactor discharge.- Chapter 2. Generalized phase stability in multipacting.- Chapter 3. Ping-pong modes.- Chapter 4. Numerical simulations of multipactor.- Part 2.. Multipactor in crossed RF fields.- Chapter 5. Introduction of accelerating RF cavities.- Chapter 6. Effect of RF cavity magnetic field on multipactor in a gap.- Chapter 7. Multipactor near the cavity equator.- Chapter 8. One-point multipactor in crossed fields of RF cavities.- Part 3. Multipacting-free cavities and transitions between cavities and beam pipes.- Chapter 9. Optimized shape cavities free of multipacting.- Chapter 10. Multipacting-free transitions between cavities and beam pipes. Theorem of minimal electric field.