The Large Hadron Collider By Kathleen McKay

What is the LHC? The most powerful particle accelerator in the world. A synchrotron (ring-shaped particle accelerator) Built by the European Organization for Nuclear Research (CERN) A part of the CERN accelerator complex The most powerful particle accelerator in the world. A synchrotron (ring-shaped particle accelerator) Built by the European Organization for Nuclear Research (CERN) A part of the CERN accelerator complex

History of the LHC The LEP (Large Electron-Positron Collider) – Built in the tunnels the LEP used to occupy Approved by CERN Council in 1994 Built Opened April 5 th 2008 Technical difficulties – Magnetic failures and a helium leak 2010 first successful experiment The LEP (Large Electron-Positron Collider) – Built in the tunnels the LEP used to occupy Approved by CERN Council in 1994 Built Opened April 5 th 2008 Technical difficulties – Magnetic failures and a helium leak 2010 first successful experiment

What does it do? It accelerates two beams of hadrons at 99% the speed of light. – Particles of Matter Uses 9,600 magnets to collide the two beams at six sites around its circumference. Observes and studies the collisions. It accelerates two beams of hadrons at 99% the speed of light. – Particles of Matter Uses 9,600 magnets to collide the two beams at six sites around its circumference. Observes and studies the collisions.

What it’s looking for… A mini Big Bang – Atomic subparticles – Matter v. Antimatter Dark Matter The Standard Model – Higgs Boson Particle String Theory – 11 dimensions – Supersymmetry

Six Collision Sites ATLAS A Toroidal LHC ApparatuS 46m long, 25m tall, 25m wide Inner tracker – Detect & analyze momentum Calorimeter – Measures energy by absorption, shows path Moun spectrometer – Measures momentum of particles too heavy to be caught by calorimeter CMS Compact Moun Solenoid General purpose Contained inside solenoid magnet – Field is 100,000 times stronger than Earth’s

Six Collision Sites cont. ALICE A Large Ion Collider Experiment Studies the collisions of iron ions Moun spectrometer Time Projection Chamber (TPC) – Tracks particle trajectories LHCb Large Hadron Collider beauty Search for antimatter – Beauty/bottom quarks 20 meters of detectors around the site to catch the quarks

The Two Small Collision Sites TOTEM TOTal Elastic and diffractive cross section Measurement Measures the size of protons Measures luminosity (how precisely an accelerator produces collisions) LHCf Large Hadron Collider forward Stimulates cosmic rays Tries to make experiments where naturally occurring cosmic rays can be observed and studied

27 km circumference 100 m underground 8 arches, 8 insertions Insertions- long straight sections, control coming and going of particles – Injection – Beam dumping – Beam cleaning 3 vacuum systems – Beam vacuum – Insulation for cryomagnets – Insulation for helium distribution line 27 km circumference 100 m underground 8 arches, 8 insertions Insertions- long straight sections, control coming and going of particles – Injection – Beam dumping – Beam cleaning 3 vacuum systems – Beam vacuum – Insulation for cryomagnets – Insulation for helium distribution line How It Works

Magnets 9,600 magnets Guides the particle beams into collisions and through insertions. 3 Kinds Quadrupole- focuses beam Accelerating Cavities- accelerate particles and keep them at constant speed Dipole- keep the beams going in a circle 8.33 T 9,600 magnets Guides the particle beams into collisions and through insertions. 3 Kinds Quadrupole- focuses beam Accelerating Cavities- accelerate particles and keep them at constant speed Dipole- keep the beams going in a circle 8.33 T

Cooling System Designed so that the magnets can conduct electricity with almost no resistance and generate a high enough magnetic field. 120 tons of super fluid helium 5 cryogenic ‘islands’ Colder than outer space: 1.9 K ( F)

Strip electrons from hydrogen atoms or lead ions to produce protons. Protons enter LINAC 2 then the PS Booster. Use radio frequency cavities to accelerate the protons to form beams. Control is transferred from the radio-frequency electric fields to the magnets. Sent to the Super Proton Synchotron (SPS). Accelerated and divided into bunches 2808 bunches in a beam, 1.1 x protons in a bunch. Then takes 20 minutes for beams to reach top speed of 11,245 trips around the LHC per second. Beams are positioned to collide at one of the six collision sites. Particle Process

Collision Results Quarks- subatomic particles Gluon- mitigating force Photons- particles of light Positrons- the anti-particles to electrons Muons- negatively charged, heavier version of electrons Quarks- subatomic particles Gluon- mitigating force Photons- particles of light Positrons- the anti-particles to electrons Muons- negatively charged, heavier version of electrons

LHC Computing Grid Tier 0 CERN’s computing system Processes information and divides it into chunks for the other two tiers. Tier 1 12 sites in various countries Receives data over dedicated computer connections at 10 gigabytes per second. Divides the information again. Tier 2 Thousands of computers at universities all over the world. Receives data through standard network connection. Processes and analyzes the data. Sends data back through the tiers to CERN. 150 million sensors in the LHC 700 megabytes of data per second 15 petabytes per year EDG (European Data Grid project) EGEE (Enabling Grid for E-sciencE) Divides the data into chunks to be analyzed separately Uses midware Uses identification and authorization procedures to keep the information safe. 150 million sensors in the LHC 700 megabytes of data per second 15 petabytes per year EDG (European Data Grid project) EGEE (Enabling Grid for E-sciencE) Divides the data into chunks to be analyzed separately Uses midware Uses identification and authorization procedures to keep the information safe.

Question 1 What does LHC stand for? 1.Luminosity Higgs Controller 2.Large Higgs Chamber 3.Low Helium Cryomagnet 4.Large Hadron Collider

Question 2 Who created the LHC? 1.CMS 2.CERN 3.TOTEM 4.EDG

Question 3 What are the names of the six detector sites? 1.CMS, ALICE, TPS, TOTEM, LEP, LHCb 2.LHCf, LEP, CMS, ATLAS, LHCb, SPS 3.ATLAS, CMS, ALICE, LHCb, TOTEM, LHCf 4.EDG, ATLAS, SPS, LEP, LHCf, CMS

Question 4 What does the LHC do? 1.Measures momentum of particles too heavy to be caught by calorimeter. 2.Guides the particle beams into collisions and through insertions. 3.Collides two beams of particles. 4.Measures energy of particles through absorption.

Question 5 What temperature are the magnets cooled to? K C K F