applications of accelerators
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Applications of Accelerators. Philip Burrows John Adams Institute for Accelerator Science Oxford University. 1. Lecture 2 outline. Application of accelerators for fundamental discoveries A bit of history Colliders Large Hadron Collider After the Large Hadron Collider. 2. - PowerPoint PPT PresentationTRANSCRIPT
Philip Burrows
John Adams Institute for Accelerator Science
Oxford University
Applications of Accelerators
1
Lecture 2 outline
2
• Application of accelerators for fundamental discoveries
• A bit of history
• Colliders
• Large Hadron Collider
• After the Large Hadron Collider
Scientific importance of accelerators
3
• 30% of physics Nobel Prizes
awarded for work based
on accelerators
• Increasing number of non-physics
Nobel Prizes being awarded
for work reliant on accelerators!
Accelerator-related Physics Nobel Prizes
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• 1901 Roentgen: X rays• 1905 Lenard: cathode rays• 1906 JJ Thomson: electron• 1914 von Laue: X-ray diffraction• 1915 WH+WL Bragg: X-ray crystallography• 1925 Franck, Hertz: laws of impact of e on atoms• 1927 Compton: X-ray scattering• 1937 Davisson, Germer: diffraction of electrons• 1939 Lawrence: cyclotron
Accelerator-related Physics Nobel Prizes
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• 1943 Stern: magnetic moment of proton• 1951 Cockcroft, Walton: artificial acceleration• 1959 Segre, Chamberlain: antiproton discovery• 1961 Hofstadter: structure of nucleons• 1968 Alvarez: discovery of particle resonances• 1969 Gell-Mann: classification of el. particles• 1976 Richter, Ting: charmed quark• 1979 Glashow, Salam, Weinberg: Standard Model• 1980 Cronin, Fitch: symmetry violation in kaons
Accelerator-related Physics Nobel Prizes
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• 1984 Rubbia, van der Meer: W + Z particles • 1986 Ruska: electron microscope• 1988 Ledermann, Schwartz, Steinerger: mu nu• 1990 Friedmann, Kendall, Taylor: quarks• 1992 Charpak: multi-wire proportional chamber• 1994 Brockhouse, Shull: neutron scattering• 1995 Perl: tau lepton discovery• 2004 Gross, Pollitzer, Wilczek: asymptotic freedom• 2008 Nambu, Kobayashi, Maskawa: broken symm.
Particle Physics Periodic Table
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Particle Physics Periodic Table
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Composition of the universe
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Dark Matter
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Composition of the universe
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Dark Energy
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Recreating conditions of early universe
Older ….. larger … colder ….less energetic
nowBig Bang
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Telescopes to the early universe
Older ….. larger … colder ….less energetic
nowBig Bang
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Large Hadron Collider (LHC)
Best window
we have on
matter in the
universe, at
ultra-early
times and at
ultra-small scales
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Interesting speculations
All eyes on collider as it comes to life
Will atom smasher signal end of the world?
Le LHC, un succès européen à célébrer
Large Hadron Collider e International Linear Collider a caccia del bosone di Higgs
Wir stoßen die Tür zum dunklen Universum auf
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For physics studies seeHeavy ion physics (Barbara Jacak)
Standard Model (Harald Fritzsch)
The LHC and the Standard Model (Albert de Roeck)
Beyond the Standard Model (John Ellis)
CP violation (Yosef Nir)
Detectors (Emmanuel Tsesmelis)
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Accelerators
• Want to see what matter is made of
• Smash matter apart and look for the building blocks
• Take small pieces of matter:
accelerate them to very high energy
crash them into one another
• LHC: protons crashing into protons head-on
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High energy is critical
Size of structure we can probe with a collider like LHC= h / p (de Broglie, 1924)
h = Planck’s constant = 6.63 x 10**-34 Jsp = momentum of protons
The larger the momentum (energy), the smaller the size
LHC exploring structure of matter at 10**20 m scale
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Why build colliders?
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Why build colliders?
60 mph stationary
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Why build colliders?
60 mph stationary
30 mph 30 mph
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Why build colliders?
60 mph stationary
30 mph 30 mph
For speeds
well below
light speed:
same damage!
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Why build colliders?
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Why build colliders?
Now try this with protons moving near light speed
stationary
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Why build colliders?
Now try this with protons moving near light speed
stationary
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Why build colliders?
stationary
For the same physics,
14,000 times the energy
of each proton in the LHC
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Why colliders?
Most of the energy goes into carrying the momentum forward
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Why colliders?
All the energy available for smashing up the protons
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Large Hadron Collider (LHC)
Largest,
highest-energy
particle
accelerator
CERN,
Geneva
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The fastest racetrack on the planet
The protons will
reach
99.9999991%
speed of light,
and go round the
27km ring 11,000
times per second
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The coldest places in the galaxy
The LHC operates at -271 C (1.9K),
colder than outer space.
A total of 36,800 tonnes are cooled to this temperature.
The largest refrigerator ever
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The emptiest vacuum in the solar system
Ten times more atmosphere on the Moon than inside LHC beam pipes
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The hottest spots in the galaxy
When the two beams of protons collide, they will generate temperatures
1000 million times hotter than the heart of the sun,
but in a minuscule space
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LHC Beams
• Each beam contains 3000 ‘bunches’ of protons
• Each bunch contains 200 billion protons
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Stored Beam Energy
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Stored Beam Energy Equivalents
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Machine Protection System
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LHC Magnets
• 27km tunnel is 50 – 150 m below ground
• Two beams of protons circulating in opposite directions
• Beams controlled by 1800 superconducting magnets, dipoles are of field strength about 8 Tesla
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Stored Magnet Energy
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LHC dipole magnets
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When Magnet Energy Escapes
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Dipole removal from tunnel
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Dipole repair on surface
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Last repaired dipole descending
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Large Hadron Collider (LHC)Back on November 20th 2009
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At last!
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Highest energy subatomic collisions
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Highest energy nuclear collisions
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Luminosity
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N number of particles in each bunchn_b number of bunches per beamf_rep repetition frequency of bunches
Number of particles passing per unit timesigma_x * sigma_ytransverse area of bunches
Number passing per unit time per unit area(‘flux’)
Event rate
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The LHC design luminosity is c. 10**34 / cm**2 / s
Number of events per second
= luminosity * cross section
600 million proton-proton collisions per second
The biggest detectors ever built
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The biggest detectors ever built
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Data rate
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About 10 Petabytes of data per year (at design luminosity)
The most extensive computer system
To analyse the data
tens of thousands of computers
around the world are being harnessed in the Grid
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After LHC?
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?
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LEP:
c. 100 GeV
per beam
Before LHC
Synchrotron radiation
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Power lost due to synchrotron radiation P ~ gamma ** 4 / r**2
gamma = E / mr = radius of trajectory
For LEP each electron loses ~ 3 GeV per turn
P = 10**-6 Watts/electron 18 MW total
Must be compensated by accelerating cavities
Synchrotron radiation
60
Suppose we increase LEP beam energy (100 GeV) by factor 5: E 500 GeV, in the same tunnel
P ~ gamma ** 4 / r**2
gamma increases by 5, so P increases by 5**4
this would give P = 5 **4 * 18 MW = 11 GW!
Compensate by increasing radius r?Need 10 x r to reduce P by 100 270km tunnel!
Synchrotron radiation
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What about LHC?
m_proton ~ 2000 * m_electron
for same E, gamma_electron ~ 2000 * gamma_proton
P_electron ~ 2000**4 * P_proton
Even for LHC, E = 70 * LEP, each proton loses only 5 keV per turn
SLAC Linear Collider
c. 50 GeV
per beam
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International Linear Collider
31 km
c. 250 GeV / beam
Philip Burrows IoP Divisional Conference, Glasgow 6//4/1164
Drive Beam Generation Complex
Main Beam Generation Complex
Delahaye
Compact Linear Collider (CLIC)
1.5 TeV / beam
Concept for beam-driven Plasma Wake Field TeV Linear Collider
Drive beam accelerator
DR e- DR e+ main beam e- injector
main beam e+ injector
Beam Delivery and IR
PWFA cells
RF gun
RF separator bunch compressor
Drive beam distribution
PWFA cells
Wim Leemans and Eric Esarey, Physics Today, March 2009
Concept of TeV e+e- collider based on laser-plasma acceleration
Engineering challenges (1)
Civil:
tunnelling, hydrology, stabilisation, survey, metrology, alignment …
Mechanical:
supports, vacuum, materials, surfaces, stability, shielding, personnel protection, remote handling, cooling systems, cryogenics, thermal management …
Electrical:
site power + distribution, powering the beams, magnets, pulsers, power supplies, amplifiers, beam dumps …
Engineering challenges (2)
Controls:
beam position, size, energy, beam orbit steering, feedback to maintain collisions, control system, data acquisition
Systems:
redundancy, reliability, efficiency, machine protection …
Human:
maintenance + repairs, operator interface, remote operation
…
Resume of lecture 2
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• Importance of accelerators for fundamental discoveries
• Why colliders + how they work
• The Large Hadron Collider is amazing
• Future high-energy colliders