CAS, CERN Accelerator School : synchrotron radiation and free electron lasers : proceedings, President Hotel, Grenoble, France, 22-27 April 1996

372 Pages·2003·14 MB·English

by  S Turner

CERN–2005–012
12November2005
ORGANISATION EUROP(cid:131)ENNE POUR LA RECHERCHE NUCL(cid:131)AIRE
CERN
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
CERN Accelerator School
Synchrotron radiation and free-electron lasers
Brunnen, Switzerland
2–9 July 2003
Proceedings
Editor: D. Brandt
GENEVA
2005
CERN–290copiesprinted–November2005
Abstract
TheseproceedingspresentthelecturesgivenattheseventeenthspecializedcourseorganizedbytheCERN
AcceleratorSchool(CAS),thetopicbeing‘SynchrotronRadiationandFree-ElectronLasers’. Similarcourses
have already been given at Chester, UK, in 1989 and at Grenoble, France, in 1996, with the proceedings
publishedasCERN90–03andCERN98–04,respectively. However, progressinthisfieldwassorapidthatit
becameimperativetoproducearevisedversionofthecourse. Afterbasicrecapitulationofbeamdynamics,the
physicsanddynamicsofelectronsisthenaddressed. Followingthisintroductorypart,amoreglobaloverview
of the field is introduced, including insertion devices, beam current and brightness limits, dedicated lattices,
current limitations, beam lifetime and quality, diagnostics and beam stability. Finally, lectures on linac free-
electronlasersandenergyrecoverylinacsarepresented. Specialemphasisisgiventhroughouttoreviewingthe
actualstateoftheartandhighlightingthelatestdevelopmentsinthefield.
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iv
Foreword
The aim of the CERN Accelerator School (CAS) to collect, preserve, and disseminate the knowledge ac-
cumulated in the world’s accelerator laboratories applies not only to general accelerator physics, but also to
relatedsub-systems,equipment,andtechnologies. Thiswideraimisachievedbymeansofspecializedcourses.
For 2003, the topic of this course was Synchrotron Radiation and Free-Electron Lasers and it was held at the
SeehotelWaldstaetterhof,Brunnen,Switzerland,from2–9July2003.
‘SynchrotronRadiationandFree-ElectronLasers’havealreadybeentreatedtwiceintheframeworkofCAS
courses,namelyin1989(Chester,UK)and1996(Grenoble,France). However,withtheenormousprogressin
the design of sources and in their range of applications, it was unanimously felt that there was an urgent need
topresentanupdatedversionofthepreviouscourses. Thisisparticularlytruewhenconsideringthenumberof
sourcesoperatedaroundtheworld,theintensityandthebrightnessachieved,thelatestdevelopmentsappliedto
insertiondevicesand,lastbutnotleast,thelargenumberofprojectsdedicatedtotheuseoffree-electronlasers.
This course was made possible by the active support of several laboratories and many individuals. In
particular, the help and encouragement of the Paul Scherrer Institute (PSI) management and staff, especially
theDirector,Prof. R.Eichler,andtheChairmanoftheLocalOrganizingCommittee,Dr. L.Rivkin,weremost
invaluable.
ThegenerousfinancialsupportprovidedbyPSIallowedCASandtheLocalOrganizingCommitteetooffer
scholarshipstohighlydeservingyoungstudents,whowouldotherwisenothavebeenabletoattendtheschool.
As always, the backing of the CERN management, the guidance of the CAS Advisory and Programme
Committees, the attention to detail of the Local Organizing Committee and the management and staff of the
SeehotelWaldstaetterhofensuredthattheschoolwasheldunderoptimumconditions.
Veryspecialthanksmustgotothelecturersfortheenormoustaskofpreparing,presenting,andwritingup
theirtopics.
Finally, the enthusiasm of the participants who came from more than 20 different countries around the
worldwasconvincingproofoftheusefulnessandsuccessofthecourse.
This school in Brunnen was my first contribution to the CAS series. I really appreciated it and would like
to thank most sincerely all the persons who helped me to make it a success, including the team of the CERN
DesktopPublishingServicefortheirdedicationandcommitmenttotheproductionofthisdocument.
DanielBrandt
CERNAcceleratorSchool
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0
June 20 Wednesday 9 July Beam Diagnostics with S.R. A. Hofmann Seminar III Shining Light on Matter F. van der Veen Students Feedback and Closing Talk
2-9 July 2003) Tuesday 8 July Diagnostics II M. Minty Linac FELs II J. Rossbach COFFEE ERLs S. Werin LUNCH New Ideas for Future Sources T. Shintake Tutorial Instabilities A Small Emittance Sources/Guns T.Shintake Demo SR Simulator DINNER
N E
RS (BRUNNE Monday 7 July Diagnostics I M. Minty Lifetime and Beam Quality III C. Bocchetta Beam Instabilities II A. Hofmann Linac FELs I J. Rossbach Tutorial Lattices and Emittances TSeminar II Fun with Formulas W. Joho Guided Study Instabilities SPECIAL
E
S
A
ME TRON L Sunday 6 July E X C U R S I O N
MC
RALE
PROGN AND FREE-E Saturday 5 July Beam Instabilities I A. Hofmann Lifetime and Beam Quality II C. Bocchetta COFFEE Insertion Devices II P. Elleaume LUNCH/POSTER Insertion Devices III P. Elleaume Tutorial Electron Dynamics Current and Brightness Limits V. Suller Guided Study Lattices and Emittances POSTERS DINNER
ON RADIATIO Friday 4 July P S I 14:00 – 14:45 Orbit Feedback M. Boege 14:45 – 15:30 Vacuum Aspects L. Schulz A 16:00 – 16:45 Mechanical Aspects S. Zelenika Dinner on the way back to Brunnen
SYNCHROTR Thursday 3 July Electron Dynamics II L. Rivkin Insertion Devices I P. Elleaume FEE Lifetime and Beam Quality I C. Bocchetta CH Lattices and Emittances II A. Streun Intro to Beam Instabilities A. Hofmann TESeminar I Experiments with Syn. Rad.: Basic Facts & Challenges for Acc. Science G. MargaritondoGuided Study Electron Dynamics DINNER
Wednesday 2 July 08:30 – 09:00 Opening Talk 09:00 – 10:00 Introduction to Relativity E. Wilson COF10:30 – 11:30 Transverse Focusing E. Wilson LUNPhase Stability J. Le Duff Physics of S.R. L. Rivkin Electron Dynamics I L. Rivkin Lattices and Emittances I A. Streun Cocktail 19:30 DINNER
Time 08 :30 09 :30 09:30 10:30 11:00 12:00 14:00 15:00 15:00 16:00 16:30 17:30 17:30 18:15 18:30 19:15

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Contents
Foreword
D.Brandt ...................................................................................... v
Specialrelativity
E.J.N.Wilson ................................................................................... 1
Transversemotion
E.J.N.Wilson .................................................................................. 17
Phasestability
J.LeDuff ..................................................................................... 41
Latticesforlightsources
A.Streun ...................................................................................... 55
Insertiondevices
P.Elleaume ................................................................................... 83
Introductiontocurrentandbrightnesslimits
V.P.Suller .................................................................................... 121
Beaminstabilities
A.Hofmann .................................................................................. 139
Linac-basedfree-electronlaser
J.Rossbach .................................................................................. 187
Energyrecoverylinacs
S.Werin ..................................................................................... 227
Diagnostics
M.Minty ..................................................................................... 239
Diagnosticswithsynchrotronradiation
A.Hofmann .................................................................................. 295
Vacuumaspects
L.Schulz ..................................................................................... 325
Mechanicalaspectsofthedesignofthird-generationsynchrotron-lightsources
S.Zelenika ................................................................................... 337
ListofParticipants .............................................................................. 363
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SPECIAL RELATIVITY
E. J. N. Wilson
CERN, Geneva
Abstract
Particles in the beams of modern accelerators travel close to the
velocity of light. A working knowledge of the Einstein’s theory of
special relativity is essential if one is to understand their behaviour. The
essentials of Special Relativity are presented in this paper in the order
in which they were discovered – from the questions raised by
Maxwell’s theory and the Michelson Morley experiment to their final
resolution in Einstein’s theory which is one of the cornerstones of
modern physics.
INTRODUCTION
If you ask a random collection of first year students, “What do you know about
relativity?” the answers might be:

“All is relative?”
“It all depends on your frame of reference.”
“You will never measure an absolute velocity unless you look into space.”
“Wasn’t it invented by the same guy that gave us the atom bomb?”

Of course none of these answers are correct and if we turn to Einstein’s rather
philosophical definition it does not give us a clue as to how to apply the principle.

The laws of physics in two systems moving with a relative velocity one to another
are equivalent.
The speed of light is finite and independent of the motion of the source.

The principle of relativity, coming after Maxwell’s equations and before quantum
theory is one of the three great discoveries upon which modern physics is based. The best
way to understand it is to follow the series of puzzles which confronted physics at the end
of the eighteenth century and see how this principle pointed to their solution.

OBSERVERS AND THEIR FRAMES OF REFERENCE

Before plunging back into history we should have a clear idea of what is meant by a
“frame of reference” and imagine the definition of the world as seen by two observers
each using their own frame of reference. It helps to think of these observers as real
people with eyes and ears and carrying clocks and rulers to measure and observe in their
respective frames of reference. We shall call them, Joe, an observer in the “laboratory”
frame of reference or coordinate system which to us appears to us stationary, and Moe, a
moving observer rooted in a frame of reference whose relative velocity to Joe is a
1
E.J.N. WILSON
vector,υ. In Figure 1 we have chosen the case where the motion is parallel to the xaxis
of both coordinate systems. Of course Moe thinks his frame of reference is stationary and
would see Joe as moving with velocity, −υ. If both Joe and Moe were to describe the
position of the same point, P, in their frames of reference, Joe in the lab would write
′ ′ ′
down three numbers x,y,z while moving Moe would write down x ,y ,z .

Fig 1:. Joe is an observer in the laboratory while Moe is traveling to the right with a
velocity,u . They describe the same point P with different coordinates x,y,z and
′ ′ ′
x ,y ,z

Fig 2:. The Michelson and Morley experiment
2