cern accelerator school superconductivity in particle accelerators

366 Pages·2005·10.66 MB·English

CERN 96-03
May 1996
XC97FF998
ORGANISATION EUROPEEWNE POUR LA RECHERCHE NUCLEAIRE
C E RN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
CERN ACCELERATOR SCHOOL
SUPERCONDUCTIVITY IN PARTICLE ACCELERATORS
Haus Rissen, Hamburg, Germany
17-24 May 1995
PROCEEDINGS
Editor: S. Turner
GENEVA
1996
2 9 if 2 4
CERN-Service d'information scientifique-RD/964-2500-mai 1996
Copyright CERN, Geneve, 1996
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ISSN 0007-8328
ISBN 92-9083-084-0
HI
ABSTRACT
These proceedings present the lectures given at the ninth specialized course organized by
the CERN Accelerator School (CAS), the topic this time being 'Superconductivity in Particle
Accelerators'. This course is basically a repeat of that given at the same location in 1988 whose
proceedings were published as CERN 89-04. However, the opportunity was taken to improve
the presentation of the various topics and to introduce the latest developments in this rapidly
expanding field. First the basic theory of superconductivity is introduced. A review of the
materials used for sc magnets is followed by magnet design requirements, the influence of eddy
and persistent currents, and the methods used to provide quench protection. Next follows the
basic theory of sc cavities, their materials, high-gradient limitations, the problem of field
emission and then their power couplers. After an introduction to cryogenics and cryoplants, the
theory of superfluidity is presented followed by a review of the use of superfluid helium.
Finally, two seminars detail the impact of superconductors on the design of the LHC and LEP2
accelerators.
CERN ACCELERATOR SCHOOL
DEUTSCHES ELEKTRONEN SYNCHROTRON
will jointly organise a course on
SUPERCONDUCTIVITY IN
PARTICLE ACCELERATORS
17-24 May 1995
at Haus Rissen, Hamburg
I
I'linlo louiiMiius Anlnili II unhiiff (nnl>H
Lectures: Cryogenics Seminars:
Superconductivity Superfluidity Impact of superconductors on LHC design
Ginsburg-Landau theory I.8K techniques Operating HERA with SC magnets
Fields, forces and mechanics of SC magnets Basic properties of cavities SC detector magnets
Survey of SC materials Materials for cavities Impact of SC cavities on LEP 2 design
Practical superconductors for magnets Quest for high RF fields Recirculating linacs
Persistent and eddy currents and their impact Field emission in cavities
on accelerator performance Couplers for cavities Visit:
Quench protection High-temperature superconductors DESY-HERA
For further information and application forms please contact:
Mrs. S. von Warlbuig,
CERN Accelerator School, E-Mail: CASDESY @ CERNVM.CERN.CH
AC Division, Fax: + 41 22 7824836 (until 15 Jan 1995)
CH-121I Geneva 23 + 41 22 7675460 (from 16 Jan 1995)
CLOSING DATE FOR APPLICATIONS: 1 MARCH 1995
PROGRAMME FOR THE CERN ACCELERATOR SCHOOL COURSE on Superconductivity in Particle Accelerators
Hamburg, 17 to 24 May 1995.
Wednesday Thursday Friday Saturday j Sunday Monday Tuesday Wednesday
Time 17 May 18 May 19 May 20 May j 21 May 22 May 23 May 24 May
BREAKFAST
09.00 Superconductivitv Superconductivity Superconductivity Ginsburg-Landau Superfluidity 1.8K High-temperature
I n III theory superconductors
10.00 P. Schmuser P. Schmuser P. Schmuser M. Cyrot W.F. Vinen P. Lebrun G. Mailer
C O F F EE C O F F EE
10.20 Fields, forces and Fields, forces and Survey of SC Practical E Persistent and Impact of Couplers for
mechanics of SC mechanics of SC materials superconductors eddy currents persistent arid eddy cavities
magnets magnets for magnets currents on II
I II X accelerator
performances
11.20 R. Perin R. Perin M. Wilson M. Wilson ! A. Devred B. Holzer E. Haebel
MDD MORNING BREAK C MID-MORNING BREAK
11.30 Cryogenics Cryogenics Basic properties of Quest for high r.f. Field emission for Couplers for TESLA
I n SC cavities field cavities cavities
u
n I
12.30 J. Schmid J. Schmid W. Weingarten D. Proch R B. Bonin E. Haebel B. Wiik
L U IS C H L U N CH
14.00 Basic properties of Poster session Operating HERA Materials for Quench protection
SC cavities with S cavities TRANSPORT
I sq>erconductiflg
:3F;; :. magnets TO
I
15.00 W. Weingarten R E.J.N. Wilson F. Willeke B. Bonin K.-R Mess AIRPORT
TEA TEA TEA
o
15.30 Impact of SC detector DESY Impact of Recirculating
superconductors magnets superconducting linacs
on LHC design E VISIT cavities on LEP2
N design
+ Buffet supper
17.00 J. Gareyte A.Dael D. Boussard D. Graf
17.30 COCKTAIL BOAT TRIP
18.30 DINNER DINNER GALA DINNER

Vll
FOREWORD
The aim of the CERN Accelerator School to collect, preserve and disseminate the
knowledge accumulated in the world's accelerator laboratories applies not only to accelerators
and storage rings, but also to the related sub-systems, equipment and technologies. This wider
aim is being achieved by means of the specialized courses listed in the Table below. The latest
of these was on the topic of Superconductivity in Particle Accelerators' and was held at Haus
Rissen, Hamburg, Germany, 17-24 May 1995, its proceedings forming the present volume.
List of specialized CAS courses and their proceedings
Year Course Proceedings
1983 Antiprotons for colliding beam facilities CERN 84-15 (1984)
1986 Applied Geodesy for particle accelerators CERN 87-01 (1987) also
Lecture Notes in Earth Sciences 12,
(Springer Verlag, 1987)
1988 Superconductivity in particle accelerators CERN 89-04 (1989)
1989 Synchrotron radiation and free-electron lasers CERN 90-03 (1990)
1990 Power converters for particle accelerators CERN 90-07 (1990)
1991 RF engineering for particle accelerators CERN 92-03 (1992)
1992 Magnetic measurement and alignment CERN 92-05 (1992)
1993 RF engineering for particle accelerators -
(repeat of the 1991 course)
1994 Cyclotrons, linacs and their applications CERN 96-02 (1996)
1995 Superconductivity in particle accelerators Present volume
Over the last few years, the importance of superconductivity in the construction of
particle accelerators and their detection systems, and in medical imaging and other measuring
devices has grown tremendously. Superconductivity has made it possible to reduce the cost,
size and power requirements of magnets, while permitting higher-energy accelerators to be
constructed within the physical constraints of existing sites, typical examples being the
TEVATRON at Fermilab and HERA at DESY. Machines constructed more recently such as
RHIC at Brookhaven or planned for the near future, particularly the LHC at CERN, would
hardly have been feasible without the use of superconductivity for both their magnets and their
RF accelerating cavities. While the accelerator applications have been the prime promoter of
recent superconductivity technology, the magnet size and cost reductions have made it possible
for many hospitals to install imaging devices to the extent that they are presently the major user
of superconducting materials. Meanwhile, serious development of the recently discovered high-
temperature superconductors promises very exciting possibilities for their use in the future.
With such a vigorous programme of superconducting applications and developments there was
every reason not only to repeat the CAS course given on this topic in 1988 but also to publish
these new proceedings.
Vlll
Organization of this course required the good will and considerable effort of many
people. In particular, CAS thanks the DESY and CERN Directorates for their financial and
moral support, the CAS Advisory Committee for its guidance, and the Programme and Local
Organizing Committees for the great attention to detail which ensured that the course was so
successful. Very special thanks must go to the lecturers at the course for their enthusiasm and
very considerable work in preparing, presenting and writing up their topics. The effort made by
the Haus Rissen staff during our stay with them was most appreciated. Finally, we thank the
participants at the course for their support and encouragement
S. Turner
Editor
IX
CONTENTS
Page no.
FOREWORD vii
P. Schmtiser
Superconductivity 1
Introduction 1
Meissner-Ochsenfeld effect and London equations 3
Thermodynamic properties of superconductors 7
Basic concepts and results of the BCS theory 14
The vector potential in quantum theory 23
Quantisation of magnetic flux 27
Hard superconductors 30
Josephson effects 36
Af. Cyrot
Ginsburg-Landau Theory
Chapter not submitted
M. Wilson
Superconducting materials for magnets 47
Introduction 47
Survey of materials 48
Conductors for use in magnets 54
Man ufacture of m agnet conductors 63
Concluding remarks 68
R. Perin
Field, forces and mechanics of superconducting magnets 71
Introduction 71
Categories of superconducting magnets for accelerators 73
Magnetic design 73
Field quality 82
Forces and mechanics 86
A. Devred and T. Ogitsu
Influence of eddy currents in superconducting particle
accelerator magnets using Rutherford-type cables 93
Introduction 93
Eddy-current sources 94
Computing the transport-current field 95
Model for intra-strand eddy currents 98
Model for inter-strand eddy currents 106
Conclusion 119
B.J. Holzer
Impact of persistent currents on accelerator performance 123
Introduction 123
Persistent currents 123
Multipole contributions of persistent currents 124
Persistent-current effects during acceleration 131
The HERA multipole correction scheme 133
Impact of persistent currents on accelerator performance 138
Correction of the persistent-current effects 139