Introduction to Accelerator Physics Scientific Tools for High Energy Physics, Synchrotron Radiation Research and Medicine Alications Pedro Castro / Accelerator Physics Grou (MPY) Introduction to Accelerator Physics DESY, 0th July 011 Alications of Accelerators (1) Particle colliders for High Energy Physics (HEP) exeriments fix target exeriments: two beams collision exeriments: Pedro Castro Introduction to Accelerators 0 th July 011 Page 1
Alications of Accelerators (1) Particle colliders for High Energy Physics (HEP) exeriments fix target exeriments: HEP detector two beams collision exeriments: Pedro Castro Introduction to Accelerators 0 th July 011 Page 3 Alications of Accelerators (1) Particle colliders for High Energy Physics exeriments Examle: the Large Hadron Collider (LHC) at CERN Lake Geneva Mont Blanc Geneva 8.6 km suerconducting magnets (inside a cryostat) Pedro Castro Introduction to Accelerators 0 th July 011 Page 4
Alications of Accelerators () Light sources for biology, hysics, chemistry exeriments Electromagnet B structural analysis of crystalline materials Xray crystallograhy (of roteins) Xray microscoy Xray absortion (or emission) sectroscoy Pedro Castro Introduction to Accelerators 0 th July 011 Page 5 Examle: DoelRingSeicher (DORIS) double ring store at DESY built between 1969 and 1974 HEP ex. until 1983 synchrotron rad. since 1980 synchrotron DORIS injection e/e exerimental stations e/e beam synchrotron light Pedro Castro Introduction to Accelerators 0 th July 011 Page 6 3
Alications of Accelerators () Xray crystallograhy Ribosome Xrays Ada Yonath Leader of MPG Ribosome Structure Grou at DESY 1986004 = 009 Nobel Prize of Chemistry together with T. Steitz and V. Ramakrishnan Pedro Castro Introduction to Accelerators 0 th July 011 Page 7 Examle: DoelRingSeicher (DORIS) double ring store at DESY history built between 1969 and 1974 HEP ex. until 1983 synchrotron rad. since 1980 synchrotron acceleratordoris control room injection e/e future synchrotron rad. until 01 HEP exerimental ex. from 01 stations e/e beam synchrotron light Pedro Castro Introduction to Accelerators 0 th July 011 Page 8 4
> About 10 accelerators for research in nuclear and article hysics > About 70 electron storage rings and electron linear accelerators used as light sources (socalled synchrotron radiation sources ) > More than 7,000 accelerators for medicine radiotheray (>7,500), radioisotoe roduction (00) > More than 18,000 industrial accelerators ion imlantation (>9,000), electron cutting and welding (>4,000) Pedro Castro Introduction to Accelerators 0 th July 011 Page 9 > About 10 accelerators for research in nuclear and article hysics > About 70 electron storage rings and electron linear accelerators used as light sources (socalled synchrotron radiation sources ) > More than 7,000 accelerators for medicine radiotheray (>7,500), radioisotoe roduction (00) < 1% > More than 18,000 industrial accelerators ion imlantation (>9,000), electron cutting and welding (>4,000) Pedro Castro Introduction to Accelerators 0 th July 011 Page 10 5
Alications of Accelerators (3) Medical alications For radioisotoe roduction roton beam stable isotoe transmutation radioactive isotoe For radiotheray and radiosurgery: xrays and gammarays ions (from rotons to atoms with atomic number u to 18, Argon) neutrons Pedro Castro Introduction to Accelerators 0 th July 011 Page 11 Alications of Accelerators (3) Medical alications For radioisotoe roduction For examle: target 18 MeV roton accelerator Oxygen18 (stable) (transmutation) Fluorine18 (halflife time = 110 min.) 97% of decays Oxygen18 ositron Pedro Castro Introduction to Accelerators 0 th July 011 Page 1 6
Alications of Accelerators (3) Medical alications For radioisotoe roduction For examle: target 18 MeV roton accelerator Oxygen18 (transmutation) Fluorine18 (halflife time = 110 min.) Fludeoxyglucose ( 18 F) Pedro Castro Introduction to Accelerators 0 th July 011 Page 13 Alications of Accelerators (3) Medical alications detectors g g Positron Emission Tomograhy (PET) Pedro Castro Introduction to Accelerators 0 th July 011 Page 14 7
Alications of Accelerators (4) For industrial alications: Alication Ion imlantation ~ 9500 Electron cutting and welding ~ 4500 Electron beam and xray irradiators ~ 000 Ion beam analysis (including AMS) ~ 00 Radioisotoe roduction (including PET) ~ 900 Nondestructive testing (including security) ~ 650 Neutron generators (including sealed tubes) ~ 1000 with energies u to 15 MeV arox. numbers from 007 (worldwide) Pedro Castro Introduction to Accelerators 0 th July 011 Page 15 Alications of Accelerators (4) For industrial alications: an examle: electron beam welding acceleration u to 6000 kev electron beam magnets as focusing lenses as well as deflectors u to 15 cm dee welding effect Pedro Castro Introduction to Accelerators 0 th July 011 Page 16 8
Alications of Accelerators (5) Many millions of television sets, oscilloscoes using CRTs (Cathode Ray Tube) TV CRT (Cathode Ray Tube) oscilloscoe Pedro Castro Introduction to Accelerators 0 th July 011 Page 17 Alications of Accelerators (5) Many millions of television sets, oscilloscoes using CRTs (Cathode Ray Tube) acceleration 5 frames / s magnets as focusing lenses as well as deflectors 65 lines Pedro Castro Introduction to Accelerators 0 th July 011 Page 18 9
GeigerMarsden exeriment: the gold foil exeriment (1909) alha articles Thomson model of the atom (1904) exected result 1 in 8000 reflected with θ > 90 shooting with 10000 km/s, a few coming back! Rutherford model of the atom (1911) Pedro Castro Introduction to Accelerators 0 th July 011 Page 19 GeigerMarsden exeriment: the gold foil exeriment (1909) alha articles Rutherford model of the atom (1911) N(θ) Thomsonmodel rediction Measurement and Rutherfordmodel rediction scattering angle θ Pedro Castro Introduction to Accelerators 0 th July 011 Page 0 10
Acceleration with an electrostatic field CockcroftWalton generator (193) DC 400 kev Lithium7 AC maximum voltage < 1 MV voltage multilier maximum voltage ~ 5 MV Van de Graaff generator Pedro Castro Introduction to Accelerators 0 th July 011 Page 1 Acceleration with an electrostatic field Van der Graaff generator: invented in 199 Pedro Castro Introduction to Accelerators 0 th July 011 Page 11
Acceleration with an electrostatic field beam V=0 V=1 MV V=0 V=0 V=0 Tandem Van der Graaff accelerator tandem = two things laced one behind the other Pedro Castro Introduction to Accelerators 0 th July 011 Page 3 Acceleration with an electrostatic field 0 MVTandem at Daresbury, UK 1 MVTandem Van de Graaff Accelerator at MPI Heidelberg, GE Pedro Castro Introduction to Accelerators 0 th July 011 Page 4 1
Limitation of electrostatic fields breakdown Pedro Castro Introduction to Accelerators 0 th July 011 Page 5 Relica of the Widerøe accelerator Pedro Castro Introduction to Accelerators 0 th July 011 Page 6 13
Acceleration using RadioFrequency (RF) generators Widerøe (198): aly acceleration voltage several times to article beam charged article E RFgenerator metallic hollow cylinders Pedro Castro Introduction to Accelerators 0 th July 011 Page 7 Acceleration using RadioFrequency (RF) generators Widerøe (198): aly acceleration voltage several times to article beam charged article E RFgenerator half a eriod later: E RFgenerator Pedro Castro Introduction to Accelerators 0 th July 011 Page 8 14
Restrictions of RF > articles travel in grous called bunches > bunches are travelling synchronous with RF cycles > ΔE Δv Pedro Castro Introduction to Accelerators 0 th July 011 Page 9 Acceleration using RadioFrequency (RF) generators β < 1 RFgenerator v T RF = v λrf c λ = β RF original Widerøe drifttube rincile relativistic β Pedro Castro Introduction to Accelerators 0 th July 011 Page 30 15
Acceleration using RadioFrequency (RF) generators β 1 (ultra relativistic articles) RFgenerator λ RF Limitations of drift tube accelerators: > only low freq. (<10 MHz) can be used L λ c drift tubes are imracticable for ultrarelativistic articles (β=1) only for very low β articles / RF tube = β = β 30 m for β=1 and f=10 MHz f RF Pedro Castro Introduction to Accelerators 0 th July 011 Page 31 Alvarez drifttube (1946) structure Widerøe drifttube rincile Cyclotron (199), E. Lawrence Pedro Castro Introduction to Accelerators 0 th July 011 Page 3 16
Resonant cavities Alvarez drifttube (1946) structure: RF resonator E E Pedro Castro Introduction to Accelerators 0 th July 011 Page 33 Examles DESY roton linac (LINAC III) Ekin β 0.3 = 50 MeV GSI Unilac (GSI: Heavy Ion Research Center) Darmstadt, Germany Protons/Ions E 0 MeV er nucleon β 0.04 0. Pedro Castro Introduction to Accelerators 0 th July 011 Page 34 17
Widerøe drifttube E RFgenerator Alvarez drifttube E Pedro Castro Introduction to Accelerators 0 th July 011 Page 35 Charges, currents and electromagnetic fields Alvarez drifttube LC circuit (or resonant circuit) analogy: L E C a quarter of a eriod later: a quarter of a eriod later: L B I C. B.. I Pedro Castro Introduction to Accelerators 0 th July 011 Page 36 18
Charges, currents and electromagnetic fields half a eriod later: L C 3 quarters of a eriod later: L half a eriod later: E 3 quarters of a eriod later: B Alvarez drifttube I C B I Pedro Castro Introduction to Accelerators 0 th July 011 Page 37 Resonant cavities Alvarez drifttube structure: RF resonator βλ RF twice longer tubes voltage between tubes V higher frequencies ossible shorter accelerator min. length of the tube t referred solution for ions and rotons u to few hundred MeV Pedro Castro Introduction to Accelerators 0 th July 011 Page 38 19
Examles Pedro Castro Introduction to Accelerators 0 th July 011 Page 39 Acceleration using RadioFrequency (RF) generators original Widerøe drifttube rincile RFgenerator first concet of the cyclotron (199) (from E. Lawrence) drifttube linac rolled u Pedro Castro Introduction to Accelerators 0 th July 011 Page 40 0
Acceleration using RadioFrequency (RF) generators original Widerøe drifttube rincile RFgenerator B first concet of the cyclotron (199) (from E. Lawrence) drifttube linac rolled u Pedro Castro Introduction to Accelerators 0 th July 011 Page 41 Cyclotron two hollow metallic Dees B ion source deflector RFgenerator accelerated ions Pedro Castro Introduction to Accelerators 0 th July 011 Page 4 1
. B (erendicular)..... R............ r r d F = dt r r = q v B momentum charge velocity of the article magnetic field circular motion: r r v B v F = q v B = m R = R m v q B π R v m q B time for one revolution: T = = π = const. Pedro Castro Introduction to Accelerators 0 th July 011 Page 43 Cyclotron in a uniform constant magnetic field: m T = π = const. (for nonrelativistic velocities) q B cyclotron frequency: ω = π = T q m B = const. rotons u to 15 MeV (β = 0.1) Pedro Castro Introduction to Accelerators 0 th July 011 Page 44
Velocity as function of energy β as function of γ Newton: E kin = 1 mv Einstein: E = E o E kin = γmc = mc 1 β v β = c relativistic relativistic γ = 3 :.8 GeV rotron 1.5 MeV electron Pedro Castro Introduction to Accelerators 0 th July 011 Page 45 Cyclotron at Fermilab, Chicago IL, USA Pedro Castro Introduction to Accelerators 0 th July 011 Page 46 3
Circular accelerators injector accelerating device straight sections magnet vacuum chamber r r v B v F = q v B = m R = R m v q B synchrotron: R is constant, increase B synchronously with E of article Pedro Castro Introduction to Accelerators 0 th July 011 Page 47 Circular accelerators Low Energy Antiroton Ring (LEAR) at CERN Pedro Castro Introduction to Accelerators 0 th July 011 Page 48 4
DESY (Deutsches Elektronen Synchrotron) DESY: German electron synchrotron, 1964, 7.4 GeV Pedro Castro Introduction to Accelerators 0 th July 011 Page 49 DESY (Deutsches Elektronen Synchrotron) DESY: German electron synchrotron, 1964, 7.4 GeV accelerator control room Pedro Castro Introduction to Accelerators 0 th July 011 Page 50 5
Electromagnet ermeability of iron = 300 10000 larger than air Pedro Castro Introduction to Accelerators 0 th July 011 Page 51 Diole magnet beam flux lines beam air ga Pedro Castro Introduction to Accelerators 0 th July 011 Page 5 6
Diole magnet cross section Max. B max. current large conductor cables Power dissiated: P = R I Pedro Castro Introduction to Accelerators 0 th July 011 Page 53 Diole magnet cross section water cooling channels Pedro Castro Introduction to Accelerators 0 th July 011 Page 54 7
Diole magnet cross section Pedro Castro Introduction to Accelerators 0 th July 011 Page 55 Diole magnet iron beam current loos Pedro Castro Introduction to Accelerators 0 th July 011 Page 56 8
Diole magnet cross section C magnet C magnet = H magnet Pedro Castro Introduction to Accelerators 0 th July 011 Page 57 Diole magnet cross section (another design) force beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 58 9
Diole magnet cross section (another design) beam beam water cooling tubes Power dissiated: current leads P = R I Pedro Castro Introduction to Accelerators 0 th July 011 Page 59 Suerconducting diole magnets LHC suerconducting dioles HERA Pedro Castro Introduction to Accelerators 0 th July 011 Page 60 30
Suerconductivity 1.5 ka normal conducting cables 1.5 ka suerconducting cable Pedro Castro Introduction to Accelerators 0 th July 011 Page 61 Suerconductivity resistance critical temerature (Tc): Pedro Castro Introduction to Accelerators 0 th July 011 Page 6 31
Diole field from conductors J = uniform current density Amere s law: r r B ds = μ0 I r B J B ds = current through the circle μ J π rb = μ0π r J B = r 0 r B B x μ J = 0 r sinθ θ μ J B y = 0 r cosθ Pedro Castro Introduction to Accelerators 0 th July 011 Page 63 Diole field from conductors J = uniform current density r B J B J Pedro Castro Introduction to Accelerators 0 th July 011 Page 64 3
Diole field from conductors J = uniform current density J. J = 0 J Pedro Castro Introduction to Accelerators 0 th July 011 Page 65 Diole field from conductors J = uniform current density B μ 0 = Jr B x μ J = μ J B y = 0 r 0 r sinθ cosθ. J J = 0 J B x μ J = 0 ( r1 sinθ1 r sinθ) 0 = μ J 0J B y = 0 ( r1 cosθ1 r cosθ) = μ d r 1 r θ θ 1 h = r = d = r1 cosθ1 ( r cosθ) 1 sinθ1 r sin θ Pedro Castro Introduction to Accelerators 0 th July 011 Page 66 33
Diole field from conductors. J B J beam constant vertical field Pedro Castro Introduction to Accelerators 0 th July 011 Page 67 From the rincile to the reality. B 15 mm x mm Aluminium collar Pedro Castro Introduction to Accelerators 0 th July 011 Page 68 34
LHC cables 1 cable houses 36 strands 1 strand = 0.85 mm diameter houses 6300 filaments cross section Coer is the insulation material between two filaments (around each filament: 0.5 µm Cu) 1 filament = 6 µm Pedro Castro Introduction to Accelerators 0 th July 011 Page 69 Comuted magnetic field B 56 mm Pedro Castro Introduction to Accelerators 0 th July 011 Page 70 35
LHC diole coils in 3D beam beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 71 LHC diole coils in 3D I B beam beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 7 36
LHC diole magnet (crosssection) ferromagnetic iron nonmagnetic collars suerconducting coils beam tubes steel container for He insulation vacuum vacuum tank suorts Pedro Castro Introduction to Accelerators 0 th July 011 Page 73 Suerconducting diole magnets LHC diole magnet interconnection: Pedro Castro Introduction to Accelerators 0 th July 011 Page 74 37
Diole antenna Pedro Castro Introduction to Accelerators 0 th July 011 Page 75 Radiation of a diole antenna Radiation of an oscillating diole Radiation of a moving oscillating diole v Lorentzcontraction Pedro Castro Introduction to Accelerators 0 th July 011 Page 76 38
Radiation of a oscillating diole under relativistic conditions diole radiation: electron trajectory DORIS: γ = 8900 PETRA: γ = 1000 Lorentzcontraction electron trajectory v = 0. 5c v = 0. 9c γ 1.15 γ. 3 electron trajectory Pedro Castro Introduction to Accelerators 0 th July 011 Page 77 Synchrotron radiation Diole magnet Power radiated by one electron in a diole field: vacuum ermitivity 4 c q γ P = 6π ε r 0 E γ = m c 0 1 q B r = Pedro Castro Introduction to Accelerators 0 th July 011 Page 78 39
Synchrotron radiation Total energy loss after one full turn: ΔE turn q = 3ε 0 4 γ r ΔE turn [GeV] = 6.03 10 18 4 γ r[m] B Pedro Castro Introduction to Accelerators 0 th July 011 Page 79 Synchrotron radiation Total energy loss after one full turn: ΔE turn q = 3ε 0 4 γ r ΔE turn [GeV] = 6.03 10 18 4 γ r[m] HERA electron ring: r = 580 m E = 7.5 GeV γ = 54000 Δ E turn same = 87 MeV (0.3%) HERA roton ring: r = 580 m E = 90 GeV γ = 980 Δ E turn 10 ev (10 9 %) need acceleration = 87 MV er turn Pedro Castro Introduction to Accelerators 0 th July 011 Page 80 40
Synchrotron radiation Total energy loss after one full turn: ΔE turn q = 3ε 0 4 γ r ΔE turn [GeV] = 6.03 10 18 4 γ r[m] HERA electron ring: r = 580 m E = 7.5 GeV γ = 54000 Δ E turn same = 87 MeV (0.3%) need acceleration = 87 MV er turn HERA roton ring: r = 580 m E = 90 GeV γ = 980 9 the limit ΔEis the turn max. 10 ev diole (10 field %) = 5.5 Tesla 1 qb r = Pedro Castro Introduction to Accelerators 0 th July 011 Page 81 Synchrotron radiation Total energy loss after one full turn: ΔE turn q = 3ε 0 4 γ r ΔE turn [GeV] = 6.03 10 18 4 γ r[m] HERA electron ring: r = 580 m E = 7.5 GeV γ = 54000 Δ E turn x5 = 87 MeV (0.3%) LEP collider: r = 800 m E = 105 GeV γ = 05000 ΔE turn 4 GeV (4%) need acceleration = 87 MV er turn need 4 GV er turn!! Pedro Castro Introduction to Accelerators 0 th July 011 Page 8 41
Synchrotron radiation Total energy loss after one full turn: ΔE turn q = 3ε 0 4 γ r ΔE turn [GeV] = 6.03 10 18 4 γ r[m] HERA electron ring: r = 580 m E = 7.5 GeV γ = 54000 Δ E turn x5 = 87 MeV (0.3%) LEP collider: r = 800 m E = 105 GeV γ = 05000 ΔE turn 4 GeV (4%) need acceleration = 87 MV er turn need 4 GV er turn!! Pedro Castro Introduction to Accelerators 0 th July 011 Page 83 Project for a future ee collider: ILC The International Linear Collider e e 15 km Colliding beams with E = 500 GeV eelc lecture on Monday, by J. Timmermans more: htt://www.linearcollider.org/ Pedro Castro Introduction to Accelerators 0 th July 011 Page 84 4
Suerconducting cavities for acceleration International Linear Collider (ILC) (future roject) Euroean Xray FreeElectron Laser (XFEL) (in construction) Freeelectron LASer in Hamburg (FLASH) (in oeration) Pedro Castro Introduction to Accelerators 0 th July 011 Page 85 RF cavity basics: the ill box cavity ill boxes Pedro Castro Introduction to Accelerators 0 th July 011 Page 86 43
Alvarez drifttube E a quarter of a eriod later: E a quarter of a eriod later: B. B.. I B.... Pedro Castro Introduction to Accelerators 0 th July 011 Page 87 I RF cavity basics: the ill box cavity E a quarter of a eriod later: B.... I B L L I C C Pedro Castro Introduction to Accelerators 0 th July 011 Page 88 44
Pill box cavity: 3D visualisation of E and B E B beam beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 89 Suerconducting cavity used in FLASH and in XFEL Suerconducting cavity used in FLASH (0.3 km) and in XFEL (3 km) 1 m RF inut ort called inut couler or ower couler beam ill box called cell Higher Order Modes ort (unwanted modes) beam RF inut ort called inut couler Pedro Castro Introduction to Accelerators 0 th July 011 Page 90 45
Accelerating field ma Simulation of the fundamental mode: electric field lines beam E Higher Order Modes ort (unwanted modes) beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 91 Advantages of RF suerconductivity resistance for DC currents! critical temerature (Tc): at radiofrequencies, there is a microwave surface resistance which tyically is 5 orders of magnitude lower than R of coer Pedro Castro Introduction to Accelerators 0 th July 011 Page 9 46
nd law of Thermodynamics Heat cannot sontaneously flow from a colder location to a hotter location max. efficiency most common alications TH T ηc = T H C thermal ower stations, cars, Carnot efficiency: TC ηc = T T H C air conditioners, refrigerators, Pedro Castro Introduction to Accelerators 0 th July 011 Page 93 Advantages of RF suerconductivity Examle: comarison of 500 MHz cavities: suerconducting cavity normal conducting cavity for E = 1 MV/m 1.5 W / m 56 kw / m at K dissiated at the cavity walls T Carnot efficiency: ηc = = 0. 007 300 T x cryogenics efficiency 030% for E = 1 MV/m 1 kw / m 56 kw / m for E = 1 MV/m 1 kw / m 11 kw / m including RF generation efficiency (50%) >100 (electrical) ower reduction factor Pedro Castro Introduction to Accelerators 0 th July 011 Page 94 47
1 m beam Number of cavities 8 Cavity length 1.038 m Oerating frequency 1.3 GHz Oerating temerature K Accelerating Gradient 3..35 MV/m beam Pedro Castro Introduction to Accelerators 0 th July 011 Page 95 Cavities inside of a cryostat beam module installation in FLASH (004) Pedro Castro Introduction to Accelerators 0 th July 011 Page 96 48
Freeelectron LASer in Hamburg (FLASH) ~300 m accelerator control room Pedro Castro Introduction to Accelerators 0 th July 011 Page 97 Euroean XRay Free Electron Laser (XFEL) Pedro Castro Introduction to Accelerators 0 th July 011 Page 98 49
First summingu Alications: HEP (examle: LHC) light source (examle: DORIS, Ribosome) medicine (examle: PET) industry (examle: electron beam welding) cathode ray tubes (examle: TV) Electrostatic accelerators: CockcroftWalton generator Tandem Van der Graaff accelerator Radiofrequency accelerators: Widerøe drifttube Pedro Castro Introduction to Accelerators 0 th July 011 Page 99 Second summingu Linear accelerators: Alvarez drifttube structure Circular accelerators: Cyclotron, E. Lawrence Synchrotron normal conducting dioles Diole magnets: suerconducting dioles Pedro Castro Introduction to Accelerators 0 th July 011 Page 100 50
Third summingu Circular colliders (synchrotrons with R=const.): limitation roton synchrotrons diole magnet electron synchrotrons synchrotron radiation Linear accelerators: International Linear Collider (ILC) Euroean Xray FreeElectron Laser (XFEL) Freeelectron LASer in Hamburg (FLASH) based on S.C. cavities Pedro Castro Introduction to Accelerators 0 th July 011 Page 101 Thank you for your attention edro.castro@desy.de Pedro Castro Introduction to Accelerators 0 th July 011 Page 10 51