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Particle Accelerators: An introduction . Lenny Rivkin Swiss Institute of Technology Lausanne (EPFL) Paul Scherrer Institute (PSI) Switzerland. PSI. EPFL. CERN. PSI. EPFL. CERN. PSI. EPFL. CERN. PSI. EPFL. CERN. The Role of Accelerators in Physical and Life Sciences
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Particle Accelerators: An introduction Lenny Rivkin Swiss Institute of Technology Lausanne (EPFL) Paul Scherrer Institute (PSI) Switzerland
PSI EPFL CERN
PSI EPFL CERN
PSI EPFL CERN
PSI EPFL CERN
The Role of Accelerators in Physical and Life Sciences “It is an historical fact that scientific revolutions are more often driven by new tools than by new concepts” Freeman Dyson
Particle beams: main uses(protons, electrons, photons, neutrons, muons, neutrinos etc.) • Research in basic subatomic physics • Analysis of physical, chemical and biological samples • Modification of physical, chemical and biological properties of matter
Accelerators in the world New Applications Total number ~ 30’000 growing at about 10% per year New technologies
ACCELERATORS: INSTRUMENTS FOR PARTICLE PHYSICS • High energy frontier • High luminosity frontier • High precision measurements
Energy available in collisions (center-of-mass energy) • Fixed target geometry • Colliding beams • or for unequal energies
Livingston plotEquivalent energy of a fixed target accelerator
COLLIDER CIRCULAR BECAME THE MOST POWERFUL ACCELERATOR FOR RESEARCH IN PARTICLE PHYSICS IP IP COLLISION AT THE IP (Interaction Point)
Luminosity Interaction rate
Point cross-section Unit: barn = 10 -24 cm2 1 pb 1 fb
History of luminosity in the world 1034cm-2s-1=10 /nb/s
Scaling of high energy proton rings LEP tunnel: 1 TeV per 1 Tesla
Scaling of high energy electron rings • Electrons emit synchrotron radiation
RF in RF out 30 – 40 km E particles “surf” the electromagnetic wave Linear Colliders damping ring rf power source e- e+ main linac beam delivery
Tunnel implementations (laser straight) Central MDI & Interaction Region
Beyound LHC? An 80 km tunnel? John Osborne (CERN), Caroline Waaijer (CERN)
Cosmic accelerators • Constellation Pictor: Pictor A X-ray image • X-ray jet originating near a giant black hole 800‘000 light years Chandra X-Ray Observatory
Useful books and references • H. Wiedemann, Particle Accelerator Physics I and IISpringer Study Edition, 2003 • K. Wille, The physics of Particle Accelerators: An IntroductionOxford University Press, 2001 • D. A. Edwards, M. J. Syphers, An Introduction to the Physics of High Energy AcceleratorsJohn Wiley & Sons, Inc. 1993 • E.J.N. Wilson, An Introduction to Particle AcceleratorsOxford University Press, 2001 • A. W. Chao, M. Tigner, Handbook of Accelerator Physics and Engineering, World Scientific 1999 • CERN Accelerator School (CAS) proceedings • E. D. Courant and H. S. Snyder, Annals of Physics: 3, 1 - 48 (1958) • M. Sands, SLAC-121
24 Nobel Prizes in Physics that had direct contribution from accelerators
19 Nobels with X-rays • Chemistry • 1936: Peter Debye • 1962: Max Purutz and Sir John Kendrew • 1976 William Lipscomb • 1985 Herbert Hauptman and Jerome Karle • 1988 Johann Deisenhofer, Robert Huber and Hartmut Michel • 1997 Paul D. Boyer and John E. Walker • 2003 Peter Agre and Roderick Mackinnon • 2009 V. Ramakrishnan, Th. A. Steitz, A. E. Yonath Physics 1901 Wilhem Rontgen 1914 Max von Laue 1915 Sir William Bragg and son 1917 Charles Barkla 1924 Karl Siegbahn 1927 Arthur Compton 1981 Kai Siegbahn Medicine 1946 Hermann Muller 1962 Frances Crick, James Watson and Maurice Wilkins 1979 Alan Cormack and Godfrey Hounsfield
Source area, S Angular divergence, W Flux, F F Brightness = constant x _________ S x W The “brightness” of a light source:
the second wave SLSSOLEIL (F)DIAMOND (UK) … ESRF SPring8 APS Moore’s Law for semiconductors XFEL 1021 1015 109 Undulators Wigglers Bending magnets Steep rise in brightness Rotating anode 1900 1950 2000 Bertha Roentgen’s hand (exposure: 20 min)
Source area, S Angular divergence, W The brightness depends on the geometry of the source, i.e., on the electron beam emittance The electron beam “emittance”: Emittance = S x W
Protons – treatment of tumors improved radiation therapy > 800 patients treated with deep-seated tumors> 5800 patients treated with eye tumors > 50 % of patients are below 40 years old
BRAGG PEAK PROTON BEAM … ALLOWS THE TREATMENT OF DEEP INSIDE LYING TUMORS WITH BEST PROTECTION OF THE SURROUNDING
Comparison of Characteristics of Photons und Protons for Radiation Therapy Dose Tumor Depth (cm)
ENERGY POSITION SPOT SCANNING
Protons IMRT -Photons Aim of proton therapy: Dose concentrated in the tumor volume,low dose or no dose to healthy tissues
CATHODE - + U Electrostatic linear accelerator • SLS DC electron gun: U = 90 kV, Ek = 90 keV COCKROFT WALTON VAN DE GRAFF TANDEM PELLETRON non-relativistic approxim.
Going beyond 1 MV • Can we repeat the process of DC acceleration? • Need time varying fields
Acceleration of slow ions Ion source Drift tubes Wideroe Linac 1928 Beam RF Transmitter fRF ~ 1–7 MHz
CATHODE - + U FOR THE SAME ENERGY EXTRACTED FROM THE FIELD, A PARTICLE WITH LOWER MASS IS MORE RELATIVISTIC v/c e p eU[MeV]
ALAVAREZ DTL FERMILAB The drift tubes are enclosed in a single resonant tank in order to avoid large radiative energy losses at higher frequencies (e.g. 200 MHz) ALVAREZ LINACS WORK UP TO b ~ 0.4 A NEW STRUCTURE IS REQUIRED FOR RELATIVISTIC PARTICLES !