Introduction to Accelerators
Rende Steerenberg - CERN - Beams Department
CERN Accelerator School Introduction to Accelerator Physics 2 – 14 October 2016 Budapest – Hungary Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Some ways of usingAccelerators The MainIngredientsof anAccelerator A very Brief HistoricOverview Why Accelerators Collidersand ? Contents CAS Budapest - 3 October 2014 2014 October 3 - Hungary 2 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Some ways of usingAccelerators The MainIngredientsof anAccelerator A very Brief HistoricOverview Why Accelerators and Colliders ? CAS Budapest - 3 October 2014 2014 October 3 - Hungary 3 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN In our accelerators we provideenergy to In thedetectors we observe matter the E =mc the particle the particle we accelerate. 2 Matter versus Energy CAS During the Big Bang Energy was Budapest - 3 October 2014 2014 October 3 transformed in matter - Hungary 4 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN λ Visiblelight = λ 400 = Looking toLooking smaller dimensions h c 700 nm 700 E λ = Increasing the energy will reduce the 0.01 X CAS - Budapest ray - 3 October 2014 2014 October 3 10 nm - Hungary wavelength Particle accelerators λ < 0.01 nm < 0.01 5 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN the target and onlypart results in usablesecondary particles Much of theenergy is lost in E Fixed Target µ Fixed Target vs. Colliders E b e a m CAS Budapest - 3 October 2014 2014 October 3 - Hungary All energy will beavailable for E = particle production E b Collider e a m 1 + E b e a m 6 2 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN improve the Verify and Standard Model Search for physics beyond the Standard Model Such Such as dark matter and dark energy The Aim CAS Budapest - 3 October 2014 2014 October 3 - Hungary Discover the boson Higgs 7 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Some ways of usingAccelerators The MainIngredientsof anAccelerator A very Brief Historic Overview Why Accelerators Collidersand ? CAS Budapest - 3 October 2014 2014 October 3 - Hungary 8 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN The The large majority Medicalapplications:10’000 ~ Industrialapplications: ~ 20’000 Accelerators Use andTheir Accelerator Science andTechnology * and and Source: World Scientific Reviews of Today:~ medicine is used in isused 30’000 industry A.W. Chao a ccelerators CAS Budapest * * - 3 October 2014 2014 October 3 - Hungary operationalworld Les than a fraction a of for research Lin. & Circ.Lin. accelerators/Colliders Synchrotronlight sources (e Cyclotrons Synchrotrons FFAG and discovery and science - wide * percent is used isused - ) 9 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • Limited by the high voltage needed Static voltage accelerator 1932: First accelerator Cockroft & Walton / van de CAS Budapest - – 3 October 2014 2014 October 3 single passage 160 - Hungary Graaff - 700 keV 10 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • • In 1939 Lawrence received the relativistic effects. D Increasing particle orbitradius Alternatingvoltage the two betweenD’s Constant field magnetic 1932: 1.2 MeV Noble prize for hiswork. evelopmentlead tothe – 1940: 20 MeV ( 20MeV 1940: Cyclotron synchro CAS Budapest - 3 October 2014 2014 October 3 E.O.Lawrence, M.S. - - Hungary cyclotron tocope the with Livingston) 11 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • A deflectingA electrodeto is use deflect theparticlefor extraction. toaccelerate them. magnetic usedtofield is bend theelectronsThe in acircle, but also winding. actuallyIt is atransformerelectrons of secondary beamas with a 1940: Kerst 2.3 MeV and very2.3 MeVquickly 300 MeV Betatron CAS Budapest - 3 October 2014 2014 October 3 - Hungary 12 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Source of Source particles . . . . . Limitedbyenergy dueto length and singlepass. Today stillfirst the stagein many accelerator complexes. high frequencypower supplies for radar technology. Developmentwas by also the progresshelped highon power made Main developmenttook placebetween 1931 and 1946. Many peopleinvolved: l 1 Linear Accelerator l 2 l 3 Wideroe Metalic drift tubes drift Metalic CAS Budapest - l 3 October 2014 2014 October 3 4 , Sloan, Lawrence,Sloan, , Alvarez,…. - Hungary l 5 l 6 ~ l 7 RF frequency with generator fixed 13 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • • • • • memo to the UK Atomic Energy directorate 1943: M. Oliphant described his synchrotron invention ina Paved way the to colliders physics Providing for beam fixed target (Courant Important focusing of particle beams Phase stability frequency Varying magnetic field andradio Fixed radius for particle orbit 1959: CERN – Snyder) - PS and BNL S ynchrotrons - AGS CAS Budapest - 3 October 2014 2014 October 3 - Hungary 14 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Some ways of usingAccelerators The Main Ingredients of an Accelerator A very Brief HistoricOverview Why Accelerators Collidersand ? CAS Budapest - 3 October 2014 2014 October 3 - Hungary 15 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN c velocity Newton: Towards Relativity E “ 1 2 Relativity mv 2 CAS Budapest not velocity mass Einstein: - 3 October 2014 2014 October 3 ” by W. Herr - Hungary increases } E energy mc 2 16 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN “ Synchrotron Light Machines &FEL Friday Tuesday The CERN Accelerator Complex Mostly Circular Machines “Luminosity & Colliders “ Linear Accelerators “ “ Cyclotrons Sources “ FFAG CAS Budapest ” by S. Sheehy ” by D. Faircloth - 3 October 2014 2014 October 3 ” by M. Seidel - Hungary ” by D. ” by G. ” by L. Alesini Papotti Rivkin Friday Wednesday . 17 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • Lets havelook at a asynchrotron: seen fromseen top,the even it isrunning. when examplean As Itookat amachine CERNthat can be • Briefly addresstheirfunction I dentifyprocessesand main componentsthe L ow A Guided A Guided Tour E nergy CAS Budapest LEIR - 3 October 2014 2014 October 3 - Hungary I on R ing 18 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN CERN - LEIR as an ExampleLEIR asan CAS Budapest - 3 October 2014 2014 October 3 - Hungary 19 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • • The particlebeam: l i “circular” machine i i arrives through a transfer line from aLINAC eaves through a transfer line s extracted s accelerated and guided overmany turns ina s injected Increase magneticfield of LEIR as an ExampleLEIR asan Acceleration & CAS Budapest Injection(s) - 3 October 2014 2014 October 3 - Hungary Extraction 20 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN The CERN LINACprovides 3 The CERN different to speciesion LEIR lines in the frontin lines transferand measurementand (Alvarez)the image back of the in acceleratingthe with structures downstreamThe LINAC part ofthe LINAC3, injector ofLEIR CAS Budapest - 3 October 2014 2014 October 3 - Hungary followbyLINAC behind the spectrometerthe with front,the in cagesource the blue ionThe in 21 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN LINACAccelerating The CERN LINACdrifttube 4 The CERN CAS Budapest - 3 October 2014 2014 October 3 - Hungary S tructure 22 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Injection Injection Injecting Injecting & Extracting Particles Extraction CAS Budapest - 3 October 2014 2014 October 3 - Hungary Extraction 23 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Circulatingbeam No magnetic field No magnetic Incomingbeam Injecting Septum Magnet Septum Magneticfield & Extracting Particles CAS Budapest - 3 October 2014 2014 October 3 - Hungary KickerMagnet Injectedbeam 24 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Circulatingbeam No magnetic field No magnetic Extractedbeam “ Kicker, Septa TransferandBeam Injecting Injecting & “ Injection andExtraction Septum Magnet Septum Magneticfield CAS Extracting Budapest - 3 October 2014 2014 October 3 - Hungary ” by M.Fraser KickerMagnet ” by M. Fraser Particles Beam extractedBeam to be 25 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Septum and Kicker Magnets CAS Budapest - 3 October 2014 2014 October 3 - Hungary 26 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Make Particles Circulate Main Main Dipoles Dipoles CAS Budapest - 3 October 2014 2014 October 3 - Hungary 27 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Lorentzforce: Charged Particlesaredeviated in magnetic fields L 2 Charged Particles Deviated 2 CAS Budapest - 3 October 2014 2014 October 3 - Hungary homogeneous homogeneous magnetic field Two charged Particlesin a ParticleB ParticleA 28 Introduction to Accelerators – CERN Accelerator School
Rende Steerenberg, CERN Horizontal homogeneousmagnetic will field cause oscillatory motion inthe Horizontal motion displacement 0 Different particles with differentinitial conditions in a Machine circumferenceMachine Oscillatory Motion ofParticles horizontal plane ParticleB CAS Budapest - 3 October 2014 2014 October 3 ParticleA Betatron - Hungary 2π Oscillations 29 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN vertical ? plane horizontalThe motion toseems be “stable”…. What about the
Vertical Many manyparticles initial Saturday displacement Many differentangles conditions “ Oscillatory Motion ofParticles Transverse Beam Dynamics “ Power Converters “ Warm Magnets s CAS Budapest Force on particles - 3 October 2014 2014 October 3 - ” by G. de Hungary ” by J. ” by B. - P. Burnet Focusing particles, Rijk a bit a bit likelight Holzer Friday 30 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Focusing the Particles Main Main Dipoles Dipoles Quadrupoles CAS Budapest - 3 October 2014 2014 October 3 - Hungary 31 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Accelerating Particles CAS Budapest - 3 October 2014 2014 October 3 - Hungary Accelerating Cavity 32 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Net result: (ceramic) Insulator No AccelerationNo + + + Accelerating Beams CAS Budapest - 3 October 2014 2014 October 3 - Hungary Then again attracted Firstattracted chamber Vacuum Deceleration Acceleration 33 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN “ Longitudinal Dynamics Beam in Circular Machines (ceramic) Insulator + + + Accelerating Beams “ RF Systems CAS Budapest - 3 October 2014 2014 October 3 ” by F. - Hungary Tecker Then repelled Firstattracted chamber Vacuum Acceleration Acceleration F RF ” by F. = h × Tecker F rev 34 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN They also make up for lostenergy in case of leptonmachines. • • • RF cavitiesare not only used to accelerate beams,but also to thebeam: shape Bunch spacing, shaping, etc. shaping, Bunch spacing, Number of bunches Longitudinal (Superconducting) in the LHC Fixed frequency cavities emittance Some RF CavitiesSome RF and feedbacks CAS Budapest - 3 October 2014 2014 October 3 - Hungary conducting) conducting) in the CERN PS Variablefrequency cavities(normal 35 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN position dataposition and Beam phase Beam Beam Position Monitor RF Beam RF Beam Control RadialPosition CAS Budapest regulation regulation - 3 October 2014 2014 October 3 Phase Beam - Hungary Radiofrequency phase (frequency) data (frequency)phase Cavity voltage and Cavity 36 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Measuring Measuring Beam Characteristics Beam Beam position/orbit measurement: • • Beam intensity or current measurement: The beam beam acts winding asa The primary Working as classical transformer Correcting orbit using automated beam steering CAS Budapest - 3 October 2014 2014 October 3 - Hungary 37 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Any many more beam properties….. Measuring Measuring Beam Characteristics • • Transverse profile/size measurement: “ (Fast) Wire scanners Secondary Emission Grids Beam Beam Instrumentation “Beam Diagnostics”“Beam • Longitudinal beam profile/size measurement: • Tomogram using wall current monitor data Use synchrotron motion for reconstruction CAS Budapest - 3 October 2014 2014 October 3 - Hungary by E. ” by ” Holzer E Holzer 38 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN resulting in Parallel moving particles create parallel currents, + These effectsThese can degrade beam quality increaseand losses attracting or repelling magnetic fields + Possible Limitations Neighbouring charges with the same polarity experience and thesystem can cause Same phase andfrequency for driving force aligned with infinite precision Machines and elements cannot bebuiltand CAS Budapest - 3 October 2014 2014 October 3 - Hungary repelling forces resonances 39 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN electric electric and magnetic acting fields back on orthe bunch beam I nduced currentsnduced in thevacuum chamber Saturday Thursday “ Non “ Possible Limitations Collective effects - Linear Linear Dynamics Beam “ Linear Imperfection CAS Budapest - 3 October 2014 2014 October 3 - Hungary ” by G. ” by A. Franchetti ( Coupled BunchInstabilities impedance) impedance) can result in ” Wolski 40 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Super conducting magnets, with 8 T or even11 T instead of 2 T Ever increasing energies intensities,and beam require specials High stored beam energies require sophisticated machine protection systems to prevent beam damage induced for normal conducting magnets, requiring cryogenics “ Beam Beam andMachine Losses Protection Special SystemsSpecial “ SC Magnets techniques CAS Budapest - 3 October 2014 2014 October 3 ” by - Hungary G. de Rijk ” by I. Strasik 41 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Some ways ofusing Accelerators The MainIngredientsof anAccelerator A very Brief HistoricOverview Why Accelerators Collidersand ? CAS Budapest - 3 October 2014 2014 October 3 - Hungary 42 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Collider Collider Physics: Light Sources: Fixed Target Physics: made between: characteristics are important. However,a major division can be For differentaccelerators and experiments differentbeam Figures of Meritinaccelerators CAS Budapest - 3 October 2014 2014 October 3 - Hungary 43 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Just a few examples among many: • • • • • Spallation Neutron Source (SNS) Oak Ridge Previously CERN to CNGS FermiLab J Neutrino physics and Spallation sources: - • • PARC High beam High beam High beam – Japan - USA F ixed Target energy intensity and /or high CAS Budapest with small sizebeam - – 3 October 2014 2014 October 3 Europe - Hungary P repetition rate hysics high - USA beam beam power 44 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • ( CERN ( Just a few examples among many: nTOF determined/selected momentum of neutrons can be With the time of flight over200 m the few MeV to several in a wide range ofenergies (from a Large amount of neutrons produced low repetition rate on a spallation target with a rather Very short ): neutron) Time offlight intense F ixed Target pulse GeV ) CAS Budapest of protons - facility 3 October 2014 2014 October 3 - Hungary P hysics 45 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • Test beamlines: Just a few examples among many: Uses often several beam lines secondary particles are The selected distributed and over of energies are produced within a rangewide energy different of particles types From single protonprimary beam intermediate intensity Preferably of low longperiods to resonant slow extraction F ixed Target CAS Budapest - 3 October 2014 2014 October 3 - Hungary P over several seconds hysics 46 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • • • Just a few examples among many: Super PhotonSuper Ring ( National Synchrotron Light Source (NSLS II) European Synchrotron Radiation Facility (ESRF) Swiss Light Source (SLS) Photon frombeam stored (highly relativistic) electron beam • • Use of High Synchrotron Light Sources electron beam intensity (Accelerator & Storage Ring) undulators SPRing to photon enhance emission – CAS Budapest Europe ) - 3 October 2014 2014 October 3 – Japan Japan - Hungary …… . And many. And more – USA – Europe … . 47 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • Beams in clockwise and anti individual eventsin thedetectors (avoid pile collisions at the same time in order to allow disentangling of aim The is to have ahigh duty cycle of collision, but not too many Electron Proton – – Proton Positron or Proton Collider 2 separate rings CAS - Budapest clockwise direction: - 3 October 2014 2014 October 3 – - Hungary Antiproton P hysics - up) single ring 48 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN • • • For collider physics the integrated luminosity is the figuremerit of The LHC The produced in2016 for ATLAS and CMS each > 30 fb Integrating this overtime results intheintegrated luminosity. of surface persecond [cm instantaneousThe luminosity is the amount of events perunit Intensity per bunch dimensions Note: Cross section is expressed in units of barns (1 barn = 10 Beam Collider Luminosity CAS Budapest - 2 - s 3 October 2014 2014 October 3 - 1 ] - Hungary Number of Number bunches Correction factors - - 1 28 49 m 2 ) Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN Use crab cavities to reduce the crossing angle effect (s) Reduce the β*( Increase ofbunches number Increase the beam brightness from the injectors (N and • • • • Tilt tothe bunches have more head Stronger focusing around the interaction points Higher harmonic RF systems More particle in smaller beams (increase brightness) Ways to Increase Luminosity Without crabbingWithout σ ) CAS Budapest - 3 October 2014 2014 October 3 - Hungary - on collision effect Withcrabbing σ ) 50 Introduction to Accelerators – CERN Accelerator School Rende Steerenberg, CERN future if we are satisfied with all those which those with all satisfied if weare future “ We shall have no better conditions in the conditions We better no have shall E. Lawrence who inventedwho LawrenceE. the cyclotronthe in 1929 we have at present.” at we have ……. much hassincethen…. changed CAS Budapest - 3 October 2014 2014 October 3 - Hungary The LHC Today LHC The Inventor andbusinessman, 1874 EdisonA. Thomas … 51 – 1931