Table Of ContentNew Techniques for
Future Accelerators
ETTORE MAJORANA
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New Techniques for
Future Accelerators
Edited by
Mario Puglisi
Pavia University
Pavia, Italy
stanislao Stipcich
INFN, Frascati National Laboratory
Frascati, Italy
and
Gabriele Torelli
Pisa University
Pisa, Italy
Plenum Press • New York and london
Library of Congress Cataloging in Publication Data
Seminar on New Techniques for Future Accelerators (1986: Erice, Sicily)
New techniques for future accelerators.
(Ettore Majorana international science series. Physical sciences)
Proceedings of the first workshop of the INFN eloisatron project: Seminar on New
Techniques for Future Accelerators, held May 11-17, 1986, in Erice, Trapani, Sicily.
Bibliography: p.
Includes index.
1. Particle accelerators-Congresses. I. Puglisi, Mario. II. Stipcich, Stanislao. III.
Torelli, Gabriele. IV. Instituto nazionale di fisica nucleare. V. Title. VI. Series.
aC787.P3S46 1986 539.713 87-20248
ISBN 978-1-4684-9116-6 ISBN 978-1-4684-9114-2 (eBook)
001 10.1007/978-1-4684-9114-2
Proceedings of the First Workshop of the INFN Eloisatron Project: Seminar on New
Techniques for Future Accelerators, held May 11-17, 1986, in Erice, Trapani, Sicily.
© 1987 Plenum Press, New York
Softcover reprint ofthe hardcover 15t edition 1987
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
PREFACE
This Seminar has been organized in Erice, in the frame of the
Eloisatron project activities, with the special purpose of bringing
together an interdisciplinary group of distinguished physicists
with prominent interest in the development of the accelerators.
Listening to the invited lectures, examining the new topics and
reviewing ideas for the acceleration of particles to energies beyond
those attainable in machines whose construction is under way or is
now contemplated are all important moments of this Seminar that will
offer to the Italian Physicists a very important opening over the
scenario of the accelerators.
In connection with the Eloisatron project developments future
Workshop-Seminars are now envisioned, each one aimed to a very
specific topic in the field of the particle accelerators.
The Editors
v
CONTENTS
Overview of Linear Collider Studies ..................•............
K. Johnsen
Principles of Beat-Wave Accelerators .............................. 15
U. de Angelis, R. Fedele and V.G. Vaccaro
Wake Field Acceleration........................................... 29
W. Bialowons, H.D. Bremer, F.-J. Decker, M. v. Hartrott,
H.C. Lewin, G.-A. Voss, T. Weiland, P. Wilhelm, Xiao
Chengde and K. Yokoya
Energy Efficiency and Choice of Parameters for Linear Colliders ... 45
J. Clauss
A Two-Stage RF Linear Colliders using a Superconducting Drive
Linac . ........ .•........ .•..... ..... ............ ... ..•....•• 67
Schne 11
\~.
The Micro Lasertron. An Efficient Switched-Power Source of mm
Wave 1e ngth Radi at ion ••.•..•.....................•.•...•...•. 89
R.B. Palmer
Collider Scaling and Cost Estimation ............................•• 105
R.B. Palmer
Cooling Rings for TeV Colliders ...............••............•..... 121
R.B. Palmer
Linear Colliders Driven by a Superconducting Linac-FEL System ... 139
U. Amaldi and C. Pellegrini
Low Technology FELs and IFELs: How can a small Laboratory
contri bute ..........................••..•..•......•.......•. 163
G. Dattoli and E. Sabia
Developments in the Physics of High Current Linear Ion
Acce 1e rators ................••......................•••.•... 181
T.P. Wangler
vii
RFQ Application 201
A. Schempp
High Power 35 GHz Testing of a Free-Electron Laser and Two-Beam
Acce 1e rator Structures •••..•••••.••••••.•••••••••••••..••••• 219
D.B. Hopkins, R.W. Kuenning, F.B. Selph, A.M. Sessler,
J.C. Clark, W.M. Fawley, T.J. Orzechowski, A.C. Paul,
D.Prosnitz, E.T. Scharlemann, S.M. Yarema and
B.R. Anderson
Acceleration of Electrons by the Field of Proton Bunches ....• 241
\~ake
A.G. Ruggiero
Analytic Tools for solving Nonlinear Problems in Particle
Accelerators; A Review and an Example ..•.•..............••.• 249
S.P. Petracca and I.M. Pinto
Approximate Solutions of the Equation for the Longitudinal
Motion of Particles in an RFQ Accelerator .......••••......•• 259
M. Leo, R.A. Leo, M. Puglisi, C. Rossi, G. Soliani and
G. Torelli
A of Four Rods RFQ ..•.............••..........•....•........ 265
I~odel
A. Fabris, A. Massarotti and M. Vretenar
RFQ Field Stabilization using Dipole Suppressors 271
M. Vretenar
Participants...................................................... 277
Subject Index ........••.......•....•..•.•.•.•••...•...•........••. 281
viii
OVERVIEW OF LINEAR COLLIDER STUDIES
K. Johnsen
CERN
Geneva, Switzerland
ABSTRACT
Against the background of the well-known Livingston diagram, the current
status and complementarity of the hadron collider projects SSC, LHC and
E10isatron, the lepton collider projects LEP and $LC, and the hybrid co1-
lider HERA are reviewed. Whereas future hadron colliders have no clear
technological limit, lepton colliders are at an turning point and
i~ortant
the search for new techniques in the direction of linear colliders is in
full flood. A natural approach is to extrapolate parameters for normal con
ducting structures to fit the special requirements of linear colliders.
Superconducting accelerating structures, the use of pulsed rather than har
monic RF power with optoe1ectric SWitches, wake fields and the plasma beat
wave scheme are some of the new ideas which are reviewed in this paper.
Much of what is included comes from the findings of the Long Range Planning
Committee established by the CERN Council under the chairmanship of
C. Rubbia.
1. INTROOUCTI ON
Particle accelerators becilllE! an tool for experimental nuclear physics from around
i~ortant
1930. Since then there has been tremendous progress in the construction of such accelerators with an
increase of about one and a half orders of magnitude in beam energy per decade, as illustrated by the
Livingston plot shown in Fig. 1. In spite of this energy increase of eight orders of magnitude the
cost of a typical accelerator installation has only gone up by one order of magnitude if inflation is
corrected for.
It is interesting to look a little more closely at how this has happened. The progress of each
type of accelerator has saturated fairly quickly, whereas new ideas have been proposed regularly and
have been the main contributors to the rapid advance. Two startling examples can be pointed out:
the invention of the alternating gradient focusing in the early fifties and the application of col
liding beams in the sixties and onwards. Fo!" the future the technological development within such
1 P ...V
100r.. .v ENERGY GRCMlTH
OF ACCELERATORS
10r.. . v
ISO
n ... v
>-
~100 G. .. V
w
z SolED
w
2: 10G. .. V
<{
w
Cl
o0:: lG...v Proton 1l.n.c
I-
<{
0::
~100MeV
w
u
u
<{ 10 MeV
1M eV
100 keY
LI ----'------'----'---"------'---.....
1930 1940 1950 ~60 1970 1980
Fig. 1 Livingston plot showing the maximum energy as a function of year
for various accelerator techniques
fields as superconductivity will be of great significance. And to satisfy the far-reaching visions
of high-energy physics in the more distant future, we may have to rely upon new inventions and
developments. This talk will be speculative on how this development will continue in the future in
order to satisfy the desires of the high-energy physics community for ever higher energy and at the
scrne time, increased luminosity. Another interesting observation can be made with reference to
Fig. 1. The highest energies attainable at present are already far beyond what can ever be reached
by fixed-target machines. In other words, when we talk about future facilities we are only talking
about accelerators that can function as colliding beam machines.
For hadron colliders there is no clear technological limit. For this reason future plans for
such colliders are based on known principles, but extended in energy and luminosity as far as one can
possibly hope to reach within assumed financial limits.
2
For electron colliders the situation is very different. The difficulties created by the radia
tion from electrons in circular machines severely limits the further development of circular electron
colliders to such an extent that it is considered unlikely that such colliders will be constructed
beyond the LEP energies. New ways must therefore be sought.
2. STUDIES OF FUTURE HADRON COLLIDERS
The highest energy hadron colliders are the proton-antiproton collider (SppS) at CERN of about
2 x 300 GeV energy and the proton-antiproton collider (Tevatron I) at Fermilab of about 2 x 800 GeV.
The former has been operational since 1982, the latter had a trial run in October, 1985, and will
operate for physics experimentation from late 1986. Both wi 11 always have inherently modest
luminosities, although these are incredibly high when we take into account how they are achieved.
The next natural step is to put proton rings with the highest possible magnetic field into the
LEP tunnel (see Fig. 2). Indeed, such considerations formed part of the arguments that determined
the radius and size of the LEP tunnel. A range of possibilities exists for such a collider. The
conceptually Simplest option would be a pp ring with a single beam channel, preferably with the
highest possible guide field. The luminosity would, however, be relatively low because antiproton
sources are not very intense. Furthermore, in order to make provision for bunch separation at
unwanted crossings, the aperture must be somewhat enlarged compared with a Single-beam machine.
Another, and probably more interesting, option would be two beam-channels side by side. For
space reasons, it is, in that case, an advantage to use the so-called "2 in I" solution to the magnet
design, i.e. the two channels within the same magnet yoke and the same cryostat. The two-channel
approach will allow high-luminosity pp collisions with many bunches. For this reason this approach
has formed the basis of some studies within ECFA and CERN of such a project. The main parameters
that have come out of these studies are listed in Tables 1 and 2.
Fig. 2 Large hadron collider in the LEP tunnel
3
