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Philip Burrows Otago University, Dunedin 13/10/081
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Making subatomic particles go very fast!
Philip Burrows
John Adams Institute, Oxford University
Visiting Oxford Fellow, Canterbury University
Particle Accelerators
Philip Burrows Otago University, Dunedin 13/10/082
Large Hadron Collider (LHC)
Largest,
highest-energy
particle
collider
CERN,
Geneva
Philip Burrows Otago University, Dunedin 13/10/083
In case you missed it …
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
Philip Burrows Otago University, Dunedin 13/10/084
Large Hadron Collider (LHC)
Largest,
highest-energy
particle
collider
CERN,
Geneva
First protons September 10th
Philip Burrows Otago University, Dunedin 13/10/085
Philip Burrows Otago University, Dunedin 13/10/086
Large Hadron Collider (LHC)
Largest,
highest-energy
particle
collider
CERN,
Geneva
Philip Burrows Otago University, Dunedin 13/10/087
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
Philip Burrows Otago University, Dunedin 13/10/088
The emptiest vacuum in the solar system
Ten times more atmosphere on the Moon than inside LHC beam pipes
Philip Burrows Otago University, Dunedin 13/10/089
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
Philip Burrows Otago University, Dunedin 13/10/0810
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
Philip Burrows Otago University, Dunedin 13/10/0811
The biggest detectors ever built
Philip Burrows Otago University, Dunedin 13/10/0812
The biggest detectors ever built
To sample and record the debris from up to
600 million proton collisions per second,
we are building gargantuan devices
to measure particles with micron precision.
Philip Burrows Otago University, Dunedin 13/10/0813
The most extensive computer system
To analyse the data
tens of thousands of computers
around the world are being harnessed in the Grid
Philip Burrows Otago University, Dunedin 13/10/0814
First event 10 September 2008
Philip Burrows Otago University, Dunedin 13/10/0815
Why build accelerators?
Philip Burrows Otago University, Dunedin 13/10/0816
Uncovering the origin of the universe
Older ….. larger … colder ….less energetic
nowBig Bang
Philip Burrows Otago University, Dunedin 13/10/0817
Telescopes to the early universe
Older ….. larger … colder ….less energetic
nowBig Bang
Philip Burrows Otago University, Dunedin 13/10/0818
Composition of the universe
Philip Burrows Otago University, Dunedin 13/10/0819
Why build 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
Philip Burrows Otago University, Dunedin 13/10/0820
Why colliders?
The higher the energy, the smaller the pieces we can reveal in the collisions
Philip Burrows Otago University, Dunedin 13/10/0821
Why colliders?
The higher the energy, the smaller the pieces we can reveal in the collisions
60 mph stationary
Philip Burrows Otago University, Dunedin 13/10/0822
Why colliders?
The higher the energy, the smaller the pieces we can reveal in the collisions
60 mph stationary
30 mph 30 mph
Philip Burrows Otago University, Dunedin 13/10/0823
Why colliders?
The higher the energy, the smaller the pieces we can reveal in the collisions
60 mph stationary
30 mph 30 mph
For speeds
well below
light speed:
same damage!
Philip Burrows Otago University, Dunedin 13/10/0824
Why colliders?
Philip Burrows Otago University, Dunedin 13/10/0825
Why colliders?
Now try this with protons moving near light speed
stationary
Philip Burrows Otago University, Dunedin 13/10/0826
Why colliders?
Now try this with protons moving near light speed
stationary
Philip Burrows Otago University, Dunedin 13/10/0827
Why colliders?
stationary
For the same physics,
14,000 times the energy
of each proton in the LHC
Philip Burrows Otago University, Dunedin 13/10/0828
Why colliders?
Most of the energy goes into carrying the momentum forward
Philip Burrows Otago University, Dunedin 13/10/0829
Why colliders?
All the energy available for smashing up the protons
Philip Burrows Otago University, Dunedin 13/10/0830
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
Philip Burrows Otago University, Dunedin 13/10/0831
How to accelerate protons to high energies?
protons carry electric CHARGE feel electric force
proton
Philip Burrows Otago University, Dunedin 13/10/0832
Accelerating protons
Apply an electric field accelerate!
Philip Burrows Otago University, Dunedin 13/10/0833
Accelerating protons
Apply an electric field accelerate!
Philip Burrows Otago University, Dunedin 13/10/0834
Accelerating protons
Apply an electric field accelerate!
+ -
V
Philip Burrows Otago University, Dunedin 13/10/0835
Accelerating protons
Apply an electric field accelerate!
+ -
V
Philip Burrows Otago University, Dunedin 13/10/0836
Accelerating protons
Apply an electric field accelerate!
+ -
V
Philip Burrows Otago University, Dunedin 13/10/0837
Accelerating electrons
+ -
V
Philip Burrows Otago University, Dunedin 13/10/0838
Accelerating electrons
+ -
V
Philip Burrows Otago University, Dunedin 13/10/0839
Accelerating electrons
+ -
V
Energy ~ voltage
Philip Burrows Otago University, Dunedin 13/10/0840
The early days
Philip Burrows Otago University, Dunedin 13/10/0841
The early days
+-
Philip Burrows Otago University, Dunedin 13/10/0842
The early days
X-rays
Philip Burrows Otago University, Dunedin 13/10/0843
First use of an accelerator in medicine!
Mrs. Roentgen’s
hand
Philip Burrows Otago University, Dunedin 13/10/0844
Cockcroft – Walton Accelerator
800,000 Volts
Philip Burrows Otago University, Dunedin 13/10/0845
Van de Graaff Accelerator
1500,000 Volts
Philip Burrows Otago University, Dunedin 13/10/0846
How many Volts???
Voltage [Volts] Size probed [metres]
Philip Burrows Otago University, Dunedin 13/10/0847
How many Volts???
Voltage [Volts]
1000,000 (Mega)
Size probed [metres]
0.000 000 000 000 1
Philip Burrows Otago University, Dunedin 13/10/0848
How many Volts???
Voltage [Volts]
1000,000 (Mega)
1000,000,000 (Giga)
Size probed [metres]
0.000 000 000 000 1
0.000 000 000 000 000 1
Philip Burrows Otago University, Dunedin 13/10/0849
How many Volts???
Voltage [Volts]
1000,000 (Mega)
1000,000,000 (Giga)
1000,000,000,000 (Tera)
Size probed [metres]
0.000 000 000 000 1
0.000 000 000 000 000 1
0.000 000 000 000 000 000 1
Philip Burrows Otago University, Dunedin 13/10/0850
How many Volts???
Voltage [Volts]
1000,000 (Mega)
1000,000,000 (Giga)
1000,000,000,000 (Tera)
LHC:
7000,000,000,000
7 trillion Volts
Size probed [metres]
0.000 000 000 000 1
0.000 000 000 000 000 1
0.000 000 000 000 000 000 1
0.000 000 000 000 000 000 01
10**-20 metres
Philip Burrows Otago University, Dunedin 13/10/0851
How to reach LHC energies?
• We need 7000,000,000,000 Volts /proton beam
How to do this??
Philip Burrows Otago University, Dunedin 13/10/0852
How to reach LHC energies?
• We need 7000,000,000,000 Volts /proton beam
How to do this??
?
Philip Burrows Otago University, Dunedin 13/10/0853
How to reach LHC energies?
• We need 7000,000,000,000 Volts /proton beam
How to do this??
?• Would need 10,000,000,000,000 AA batteries
Philip Burrows Otago University, Dunedin 13/10/0854
How to reach LHC energies?
• We need 7000,000,000,000 Volts
How to do this??
?• Would need 10,000,000,000,000 AA batteries• 5 x 10**11 m = 3 x Earth’s orbit radius around Sun
Philip Burrows Otago University, Dunedin 13/10/0855
How to reach LHC energies?
• We need 7000,000,000,000 Volts
How to do this??
?• Would need 10,000,000,000,000 AA batteries• 5 x 10**11 m = 3 x Earth’s orbit radius around Sun• $30,000,000,000,000 – discount for bulk buy?!
Philip Burrows Otago University, Dunedin 13/10/0856
Accelerating Technology
• Batteries have too low voltage per metre:
1.5 Volts per 5 cm = 30 Volts / m (‘gradient’)
Philip Burrows Otago University, Dunedin 13/10/0857
Accelerating Technology
• Batteries have too low voltage per metre:
1.5 Volts per 5 cm = 30 Volts / m (‘gradient’)
• Forefront accelerating gradients ~ 30 MILLION Volts / m
• Hence largest accelerator (LHC) is **ONLY** 27 km long!
Philip Burrows Otago University, Dunedin 13/10/0858
Accelerating Technology
• Batteries have too low voltage per metre:
1.5 Volts per 5 cm = 30 Volts / m (‘gradient’)
• Forefront accelerating gradients ~ 30 MILLION Volts / m
• Hence largest accelerator (LHC) is **ONLY** 27 km long!
• Accelerate using radio-frequency EM waves launched
into metal cavities …
• Protons gain energy by ‘surfing’ the waves
Philip Burrows Otago University, Dunedin 13/10/0859
Niobium Accelerating Structures
Philip Burrows Otago University, Dunedin 13/10/0860
Human surfer
Philip Burrows Otago University, Dunedin 13/10/0861
Subatomic surfer
+
-
+
Electro-
magnetic wave
E
Philip Burrows Otago University, Dunedin 13/10/0862
Large Hadron Collider (LHC)
Philip Burrows Otago University, Dunedin 13/10/0863
More about LHC
• 27km tunnel is 50 – 150 m below ground
Philip Burrows Otago University, Dunedin 13/10/0864
More about LHC
• 27km tunnel is 50 – 150 m below ground
• Two beams of protons circulating in opposite directions
• Beams controlled by 1800 superconducting magnets (8 T)
Philip Burrows Otago University, Dunedin 13/10/0865
More about LHC
• 27km tunnel is 50 – 150 m below ground
• Two beams of protons circulating in opposite directions
• Beams controlled by 1800 superconducting magnets (8 T)
• Each beam contains 3000 ‘bunches’ of protons
• Each bunch contains 200 billion protons
Philip Burrows Otago University, Dunedin 13/10/0866
More about LHC
• 27km tunnel is 50 – 150 m below ground
• Two beams of protons circulating in opposite directions
• Beams controlled by 1800 superconducting magnets (8 T)
• Each beam contains 3000 ‘bunches’ of protons
• Each bunch contains 200 billion protons
• 600 million proton-proton collisions per second
Philip Burrows Otago University, Dunedin 13/10/0867
Large Hadron Collider (LHC)
Will give us a first look at
new physics landscape.
Panoramic view,
but with low resolution:
‘broad-band’ survey:
A precision microscope (‘narrow-band’ instrument) is
needed to illuminate the features in the new landscape …
Philip Burrows Otago University, Dunedin 13/10/0868
International Linear Collider
31 km
Philip Burrows Otago University, Dunedin 13/10/0869
Linear Colliders for electrons + positrons
Stanford
Linear
Accelerator
Center
(California)
Philip Burrows Otago University, Dunedin 13/10/0870
Accelerators Worldwide
• High-energy accelerators 120
• Synchrotron radiation X-ray sources 100
Philip Burrows Otago University, Dunedin 13/10/0871
Diamond: synchrotron source of X-rays
Philip Burrows Otago University, Dunedin 13/10/0872
Accelerators Worldwide
• High-energy accelerators 120
• Synchrotron radiation X-ray sources 100
• Radiotherapy7700
• Biomedical research 1000
Philip Burrows Otago University, Dunedin 13/10/0873
Clatterbridge: cancer treatment w protons
Philip Burrows Otago University, Dunedin 13/10/0874
Accelerators Worldwide
• High-energy accelerators 120
• Synchrotron radiation X-ray sources 100
• Radiotherapy 7700
• Biomedical research 1000
• Industrial processing 1500
• Ion implanters, surface modification 7000
Total 17,500
Philip Burrows Otago University, Dunedin 13/10/0875
Large Hadron Collider (LHC)