Table Of ContentPhv s i cs
Tech no Io g LJ.,
of Linear Accelerator Systems
Phpics
J Technology
of Linear Accelerator Systems
Proceedings of the 2002
J o i n t U S PAS - C A S - J a p an - R u s s i a
Accelerator School
Long Beach, California 6 - 14 November 2002
editors
Helmut Wiedemann
Stanford University, USA
Daniel Brandt
C ER N. Switzerland
Eugene A Perevedentsev
The Budker Institute of Nuclear Physics, Russia
S hin-ic h i Ku ro kawa
KEK, Japan
r pW orld Scientific
N E W J E R S E Y L O N D O N * S I N G A P O R E S H A N G H A I * HONG KONG T A I P E I * C H E N N A I
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PHYSICS AND TECHNOLOGY OF LINEAR ACCELERATOR SYSTEMS
Proceedings of the 2002 Joint USPAS-CAS-Japan-Russia Accelerator School
Copyright 0 2004 by World Scientific Publishing Co. Pte. Ltd.
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PREFACE
Following a long tradition we organized a biannual Joint Particle Accelerator
School, JAS2002. These schools started in 1985 as ajoint venture between the
CERN and the US Particle Accelerator Schools. Each school is dedicated to a
particular Particle Accelerator topic addressing status and ongoing developments
within that theme. The first five schools were:
Nonlinear Dynamics, Santa Margherita di Pula, Sardinia, Italy, 1985
New Acceleration Methods and Techniques, South Padre Island, USA, 1986
Observation, Diagnosis and Correction, Anacapri, Italy, 1988
Beam Intensity Limitations, Hilton Head Island, SC, USA, 1990
Factories with e+ e- Rings. Benelmadena, Spain, 1992
Proceedings of these five schools were published in the Lecture Notes in
Physics series by Springer as volumes 247,296,343,400a nd 425.
In 1993 the KEK Particle Accelerator School (KEKPAS) joined and resulted
in the following schools:
Frontiers of Accelerator Technology, Maui, Hawaii, USA, 1994
Radio Frequency Engineering for Particle Accelerator Physics,
Hayama and Tsukuba, Japan, 1996
Proceedings for these two schools were published by the World Scientific
Publishing Company.
Finally in 1996 the Russia Accelerator School joined and the location of these
schools rotates now within those four regions:
Beam Measurement, Montreux and CERN, Switzerland, 1998
World Scientific Publishing Company.
High Quality Beams, St. Petersburg and JINR, Dubna, 2000
AIP Conference Proceedings #592
Linear Accelerator, Long Beach, CA, USA, 2002
World Scientific Publishing Company.
V
vi
On behalf of the JAS2002 we express our sincere thanks to S.Y. Lee, M. Paul
and S. Winchester of the US Particle Accelerator School for the excellent
planning and execution of the school. We also thank David Sutter from the US
Department of Energy and F. Bernthal from the Universities Research
Association (URA) for their financial support, and the regional Accelerator
School organizations (CAS, KEKPAS, RAS) for their continued support and
encouragement. Our special thanks goes to the lecturers who agreed to share
their intellectual experience at the school and document their lectures in these
proceedings. We appreciate the editing skills of Margaret Dienes who has
supported our efforts to produce quality proceedings since 1985. Last but not
least we thank all the participants for their attendance and participation at the
lectures.
D. Brandt, CAS, Geneva, Switzerland
S.I. Kurokawa, KEKPAS, Tsukuba, Japan
E. Perevedentsev, Russia Accelerator School, Novosibirsk, Russia
H. Wiedemann, USPAS, Stanford, CA, USA
October 15,2003
CONTENTS
Preface v
Ion Linacs 1
T. P. Wangler
Modern Trends in Induction Accelerator Technology 24
G. J . Caporaso
RFQ - Accelerators 60
A. Schempp
RF Structures (Design) 79
H. Henke
Fabrication and Testing of RF Structures 130
E. Jensen
Computational Tools for RF Structure Design 155
E. Jensen
Wakefields and Instabilities in Linacs 180
G. Stupakov
Beam Manipulation and Diagnostic Techniques in Linacs 213
P. Logatchov
Space Charge and Beam Halos in Proton Linacs 257
F. Gerigk
Power Sources for Accelerators beyond X-Band 289
E. R. Colby
Recirculated and Energy Recovered Linacs 30 1
G. A . Krafst
Muon Colliders and Neutrino Factories: Basics and Prospects 322
A. Skrinsky
vii
Members of the Organizing Institutions
US Particle Accelerator School (USPAS)
H. Wiedemann, S.Y. Lee, M. Paul, S. Winchester
CERN, Accelerator School (CAS)
D. Brandt, E.J.N. Wilson, S. von Wartburg
KEK Accelerator School (KEKPAS)
S.I. Kurokawa, Y. Hayashi
Russia Accelerator S c h d
E.A. Perevedentsev
Program Committee
USPAS: A. Chao, G. Krafft, S.Y. Lee, R. Ryne, M. Syphers
CAS: J. Miles, E.J.N. Wilson,
Japan Acc.Schoo1: S.I. Kurokawa, H. Matsumoto, K. Nakajima, S. Ohsawa
Russia AccSchool: I.N. Meshkov, E.A. Perevedentsev, Y.M. Shatunov
Sponsors
USDOE, CERN, KEK, Budker Institute, URA
...
Vlll
Ion Linacs
Thomas P. Wangler
Los Alamos National Laboratory
Los Alamos, New Mexico 87545
An overview is presented of accelerator physics and technology of ion linear accelerators. Topics
include early history, basic principles, medium- and high-velocity accelerating structures, the
radiofrequency quadrupole (RFQ), modem ion-linac architecture,l ongitudinal and transverse single-
particle beam dynamics, multiparticle dynamics and space charge, and recent results on beam halo.
1. Introduction and Early History of Ion Linacs
We begin our discussion of ion linacs with some general observations about
linacs. In a radiofrequency (RF) linac, the beam is accelerated by radiofrequency
electromagnetic fields with a harmonic time dependence. The RF linear
accelerator is classified as a resonance accelerator. Because both ends of the
structure are grounded, a linac can easily be constructed as a modular array of
accelerating structures, and there is no physical limit to the energy gain in a
linac. The first formal proposal and experimental test of a linac was by Rolf
Wideroe in 1928,' but linear accelerators that were useful for research in nuclear
and elementary particle research did not appear until after the developments of
microwave technology during World War 11, stimulated by radar programs.
Since then, the progress has been rapid, and today the linac is not only a useful
research tool but is also being developed for many other important applications.
A main advantage of the linear accelerator is its capability for producing
high-energy, and high-intensity charged-particle beams of high beam quality,
where beam quality can be related to a capability for producing a small beam
diameter or small angular spread, and small time spread of the beam pulses or
small energy spread. Other attractive characteristics include the following: (a)
strong focusing can easily be provided to confine a high-intensity beam; (b) the
beam traverses the structure in a single pass, and therefore repetitive error
conditions causing destructive beam resonances are avoided; (c) because the
beam travels in a straight line, there is no power loss from synchrotron radiation,
which is a limitation for high-energy electron beams in circular accelerators; (d)
injection and extraction are simpler than in circular accelerators, since the
natural orbit of the linac is open at each end; special techniques for efficient
beam injection and extraction are unnecessary; (e) the Iinac can operate at any
duty factor, all the way to 100% duty or a continuous-wave (CW).
For proton and deuteron linacs, modern applications include: (a) injectors to
high-energy synchrotrons for elementary-particle-physics research, (b) high-
energy linacs for CW spoliation neutron sources used for condensed matter and
materials research, production of nuclear fuel, transmutation of nuclear wastes,
and accelerator-driven fission-reactor concepts, (c) CW neutron sources for
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