Glenn Patrick Rutherford Appleton Laboratory
http://hepwww.rl.ac.uk/pust/masterclass.htm
INTRODUCTIONA Very Brief Guide
to Accelerators
RAL Masterclasses 2009
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Microscopes & Telescopes ~ 400 Years Ago
Galileo’s telescope, ~1609, FlorenceMagnification ~30
Compound microscope
~1670, Glasgow
Magnification ~30
Siderius Nuncius,Galileo Galilei, 1610
MicrographiaRobert Hooke, 1665
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Small Scales and Large Scales - Today
Hubble Ultra Deep Field (2004)
Large Hadron Collider (2009)
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E = mc2E = mc2
E kTE kT
Particle Physics
Astronomy
5
Probing Matter
p
h
Higher energies means shorter wavelengths.
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Cosmic Particles
Accelerators!
Interactions in the atmosphereLow flux of particlesDifficult to identify/control
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Force on charged particle is given by the Lorentz Force
BvqEqF
Charged Particle Beams
Electric FieldAcceleration Magnetic Field
Bending
Cathode(-) Anode(+)
e-
p+
e+ e-
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John Cockroft & Ernest Walton Voltage Multiplier
Cavendish Laboratory, 1932.
1897 – J.J. Thomson
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Cockroft/WaltonPre-Injectors
750kV FermiLab
665 kV ISIS, RAL(replaced 2004)
1010
Fermilab (400 MeV)
+ - ++ + --Alternating RF voltage. Each step gives a small energy increase to the particle.
LINEAR ACCELERATORS
1111
2 mile Linear Accelerator, SLAC, Stanford
Wor
ld’s
long
est b
uild
ing
World’s stra
ightest build
ing
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Cyclotron
First circular particle accelerator built by Ernest O. Lawrence & Stanley
Livingston at Berkeley in 1930.
Energy = 80 keV, Diameter = 13cm
Circular Accelerators
13 cm
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Principal Components of a Synchrotron
In a Collider, bunches of particles/antiparticlescirculate in opposite directions.
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Super Proton Synchrotron CERN, Geneva
(6km circumference)
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Radio Frequency Cavities
Large Electron Positron Collider (LEP) 1989-2000
27 km circumference
3,000 bending magnets
800 focussing magnets
11,000 revolutions/sec
LEP (CERN)
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Electromagnetic waves accelerate particles in the same way that waves propel surfers.
Timing is vital!
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Sextupole (LEP)Correction of chromatic spread.
Focussing Magnets
Quadrupole (LEP)
Strong FocussingBeam alternatelyfocussed in horizand vert planes.
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HERA – Electron Proton Collider (6.3 km)
p
920 GeV protons
27.5 GeV electrons/positrons
e
ɣproton
Hamburg, 1992-2007Hamburg, 1992-2007
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Tevatron, FermiLab, Chicago
Collides protons and anti-protonsEnergy = 1 TeV (1000 GeV)
4 mile circumference
Main injector
Tevatron
2020
Synchrotron RadiationDiamond Light Source
Started operation Feb 2007. Uses synchrotron radiation for studies at
molecular/atomic level.
e
4
0
1
m
E
RE
You are here
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International Linear Collider
~31 km
250 GeV electrons colliding with 250 GeV positrons
8 February 2007 Reference Design Report2010 – 2012 Technical Design Phase? Construction/Operation
The Next Generation?
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Masterclass Programme09:30 Arrival, Coffee and Doughnuts (R18)
10:00 Welcome Caroline Callard10:05 A Very Brief Guide to Accelerators Dr. Glenn Patrick
10:20 Fundamentals of Particle Physics Dr. Stefania Ricciardi11:00 Introducing Diamond Dr. David Price11:15 Introducing ISIS Dr. Martyn Bull
11:35 Group A: Visit to ISIS or Diamond Group B: Computer Session Drs. Tricoli & Wielers
12:30 Buffet Lunch (R18)
13:30 The Large Hadron Collider Dr. Kristian Harder
14:15 Group B: Visit to ISIS or DiamondGroup A: Computer Session Drs. Tricoli & Wielers
15:15 Tea
15:30 Applications of Particle Accelerators Dr. Rob Edgecock
16:00 Question and Answer Session16:15+ End
Material can be found at: http://hepwww.rl.ac.uk/pust/masterclass.htm
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Energy Units!
1 eV = 1 electron VoltEnergy to ionise hydrogen = 13.6 eV
1 keV(kilo) = 1,000 eV = 103 eVMedical X-ray ~ 200 keV
1 MeV(Mega) = 1,000,000 eV = 106 eVAlpha particle decay of uranium 4.2 MeV
1 GeV(Giga) = 1,000,000,000 eV = 109 eVLEP collider beam (1989-200) = 45 GeV
1 TeV(Tera) = 1,000,000,000,000 eV = 1012 eVHighest energy accelerator in world = 1 TeV (Tevatron)
Electron Volt – Energy gained by an electron when accelerated in an electric field through a potential difference of 1 volt.
Highest energiesfound in cosmic rays (>1020 eV)