Large Hadron Collider

1. Large Hadron Collider Abigail Bickley, Dept of Chemistry, July 25, 2008

2. Where is the LHC? Abigail Bickley, PAN 2008

3. Where is the LHC? Switzerland Circumference: 27km = 16.8miles France Abigail Bickley, PAN 2008

4. Where is the LHC? Abigail Bickley, PAN 2008

5. Deconstructing a Name • Collider: • Two beams of particles circulate in opposite directions around the ring • Beams intersect at 4 locations • These locations are where the collisions occur and are observed by warehouse sized detectors • Hadron • Large Abigail Bickley, PAN 2008

6. Deconstructing a Name u u d 10-15 m 10-10 m 10-9 m • Collider • Hadron: • General category for the type of particles accelerated (protons and heavy nuclei) • Hadrons (from the Greek ‘adros’ meaning ‘bulky’) are particles composed of quarks. The protons and neutrons that atomic nuclei are made of belong to this family. On the other hand, leptons are particles that are not made of quarks. Electrons and muons are examples of leptons (from the Greek ‘leptos’ meaning ‘thin’). • Large Abigail Bickley, PAN 2008

7. Deconstructing a Name • Large: • The size of an accelerator is related to the maximum beam energy obtainable. • This is a function of the radius of the machine and the strength of the dipole magnetic field that keeps particles in their orbits. • The LHC re-uses the 27‑km circumference tunnel that was built for the previous big accelerator, LEP. • The size of the tunnel, magnets, cavities and other essential elements of the machine, represent themain constraints that determine the design energy of 7 TeV per proton beam. Abigail Bickley, PAN 2008

8. Colliders vs Cyclotrons • Cyclotrons: • Produces a single beam of ions that are directed towards a stationary target • Maximum beam energy is dependent upon the radius of the cyclotron • Colliders: • When two beams collide, the energy of the collision is the sum of the energies of the two beams. • A beam of the same energy that hits a fixed target would produce a collision of much less energy. Abigail Bickley, PAN 2008

9. Recipe for Creating an Ion Beam • Ion Source: • All protons accelerated at CERN are obtained from standard hydrogen. • Protons are isolated by stripping orbiting electrons off of hydrogen atoms. • Although proton beams at the LHC are very intense, only 2 nanograms of hydrogen are accelerated each day. • It would take the LHC about 1 million years to accelerate 1 gram of hydrogen. Abigail Bickley, PAN 2008

10. Recipe for Creating an Ion Beam • Multi-Stage Acceleration: • The accelerator complex is a succession of machines with increasingly higher energies. • Each machine injects the beam into the next one, which brings the beam to an even higher energy. 7000 GeV 450 GeV 1.4 GeV 25 GeV 0.050 GeV Abigail Bickley, PAN 2008

11. Recipe for Creating an Ion Beam • LHC = Final Acceleration • Protons at full energy in the LHC will be traveling at 0.999999991 times the speed of light. • Each proton will go round the 27 km ring more than 11,000 times a second. • Entire acceleration process takes ~30min Abigail Bickley, PAN 2008

12. Recipe for Creating an Ion Beam • Collision Tuning: • Beam is produced in “bunches” not a continuous stream of particles. • A filled ring contains 2808 bunches. • Each bunch contains 1.1x1011 protons • Arrival of bunches from both beams at the interaction region must be timed perfectly to create collisions • 600M collisions per second Abigail Bickley, PAN 2008

13. Power Consumption • Annual operation requires 800,000 MWh • Equivalent to the entire state of Geneva • Machine only operates 270 days/year • Cooling of the superconducting magnets consumes the majority of the power (9593 total magnets) • Electricity is provided by France • 20% of French electricity is generated in nuclear power plants Abigail Bickley, PAN 2008

14. CERN Price Tag Annual energy cost: $30M Abigail Bickley, PAN 2008

15. Existing Colliders/Accelerators RHIC from space Abigail Bickley, PAN 2008

16. Why Collide Nuclei? Abigail Bickley, PAN 2008

17. Evolution of the Universe LHC equivalent to t = 10-25seconds. As time progressed the universe expanded and cooled. Free quarks and gluons became confined. Abigail Bickley, PAN 2008

18. The Particle Zoo Proton • The nucleus of an atom is composed of protons & neutrons • But these particles also have a quark substructure • Proton = uud • Neutron = udd • The antimatter equivalent to the proton is the antiproton (uud) Abigail Bickley, PAN 2008

19. The Particle Zoo Abigail Bickley, PAN 2008

20. Scientific Goals of LHC: Higgs Boson http://www.oufusion.org.uk/newssummer01/fusionnewssummer01.htm ‘Well, either we've found the Higgs boson, or Fred's just put the kettle on’ • The Higgs boson is a hypothesised particle which, if it exists, would give the mechanism by which particles acquire mass. • Referred to in the lay press as the “God particle” • Higgs proposed that the whole of space is permeated by a field, similar in some ways to the electromagnetic field. • As particles move through space they travel through this field, and if they interact with it they acquire what appears to be mass. • This is similar to the action of viscous forces felt by particles moving through any thick liquid. the larger the interaction of the particles with the field, the more mass they appear to have. • Force carrier of the Higgs field is the Higgs boson. Abigail Bickley, PAN 2008

21. Scientific Goals of LHC • What is dark matter? • Observations of visible matter accounts for only 4% of the Universe. • The search is open for particles or phenomena responsible for dark matter (23%) and dark energy (73%). • A very popular idea is that dark matter is made of neutral but still • undiscovered supersymmetric particles. • The gravitational effect of dark matter may make galaxies spin faster • than expected • The gravitational field of dark matter deviates the light of objects • behind it. Abigail Bickley, PAN 2008

22. Common Misconceptions Massive Black Hole • Public concern exists about the possibility of black hole creation at LHC • Macroscopic Black Holes: • Massive black holes are formed in nature as a result of star collapse • Results in a very large amount of matter being confined to a very small volume • Microscopic Black Holes: • Theoretical existence • Created in high energy collisions of particles such as the protons • Public concern is that the energy of the collisions at the LHC will be sufficient to create microscopic black holes • Scientific Rebuttal: • Cosmic rays are particles produced in outer space that are accelerated to energies far exceeding those of the LHC. • Cosmic rays travel throughout the Universe, and have been bombarding the Earth’s atmosphere continually since its formation 4.5 billion years ago. • Since the much higher-energy collisions provided by nature for billions of years have not harmed the Earth, there is no reason to think that any phenomenon produced by the LHC will do so. Abigail Bickley, PAN 2008

23. Watching a Collision Time ~6x10-24s ~21x10-24s >21x10-24s 0 fm/c ~2 fm/c ~7 fm/c >7fm/c • Microscopic view Remember: E=mc2 so lots of energy means lots of mass!!! Abigail Bickley, PAN 2008

24. Watching a Collision Abigail Bickley, PAN 2008

25. The Detectors: CMS • Compact Muon Solenoid • Cylindrical detector • 69ft long • 52ft diameter • 25,000,000lbs • Cost: • $480M • Collaboration: • ~2600 people • 180 institutions • 38 countries Scientific Goal: general‑purpose detector designed to cover the widest possible range of physics, from the search for the Higgs boson to supersymmetry (SUSY) and extra dimensions Abigail Bickley, PAN 2008

26. The Detectors: CMS • Compact Muon Solenoid • Cylindrical detector • 69ft long • 52ft diameter • 25,000,000lbs • Cost: • $480M • Collaboration: • ~2600 people • 180 institutions • 38 countries Scientific Goal: general‑purpose detector designed to cover the widest possible range of physics, from the search for the Higgs boson to supersymmetry (SUSY) and extra dimensions Abigail Bickley, PAN 2008

27. The Detectors: ATLAS • No acronym • Dimensions • 151ft long • 82ft diameter • 7,000,000lbs • Cost: • $520M • Collaboration: • 1900 people • 164 institutions • 35 countries Scientific Goal: general‑purpose detector designed to cover the widest possible range of physics, from the search for the Higgs boson to supersymmetry (SUSY) and extra dimensions Abigail Bickley, PAN 2008

28. The Detectors: ATLAS • No acronym • Dimensions • 151ft long • 82ft diameter • 7,000,000lbs • Cost: • $520M • Collaboration: • 1900 people • 164 institutions • 35 countries Scientific Goal: general‑purpose detector designed to cover the widest possible range of physics, from the search for the Higgs boson to supersymmetry (SUSY) and extra dimensions Abigail Bickley, PAN 2008

29. The Detectors: ALICE • A Large Ion Collider Experiment • Cylindrical detector • 85ft long • 52ft diameter • 10,000,000lbs • Cost: • $110M • Collaboration: • 1500 people • 104 institutions • 31 countries Scientific Goal: specialized in analysing lead-ion collisions. It will study the properties of quark-gluon plasma, a state of matter where quarks and gluons, under conditions of very high temperatures and densities, are no longer confined inside hadrons. Such a state of matter probably existed just after the Big Bang, before Particles such as protons and neutrons were formed. Abigail Bickley, PAN 2008

30. The Detectors: ALICE • A Large Ion Collider Experiment • Cylindrical detector • 85ft long • 52ft diameter • 10,000,000lbs • Cost: • $110M • Collaboration: • 1500 people • 104 institutions • 31 countries Scientific Goal: specialized in analysing lead-ion collisions. It will study the properties of quark-gluon plasma, a state of matter where quarks and gluons, under conditions of very high temperatures and densities, are no longer confined inside hadrons. Such a state of matter probably existed just after the Big Bang, before Particles such as protons and neutrons were formed. Abigail Bickley, PAN 2008

31. The Detectors: ALICE • A Large Ion Collider Experiment • Cylindrical detector • 85ft long • 52ft diameter • 10,000,000lbs • Cost: • $110M • Collaboration: • 1500 people • 104 institutions • 31 countries ALICE Virtual Tour Scientific Goal: specialized in analysing lead-ion collisions. It will study the properties of quark-gluon plasma, a state of matter where quarks and gluons, under conditions of very high temperatures and densities, are no longer confined inside hadrons. Such a state of matter probably existed just after the Big Bang, before Particles such as protons and neutrons were formed. Abigail Bickley, PAN 2008

32. The Detectors: LHCb • Large Hadron Collider beauty • Dimensions • 69ft long • 33ft high • 43ft wide • 5,600,000lbs • Cost: • $520M • Collaboration: • 650 people • 47 institutions • 14 countries Scientific Goal: specializes in the study of the slight asymmetry between matter and antimatter present in interactions of B-particles (particles containing the b quark). Understanding it should prove invaluable in answering the question: “Why is our Universe made of the matter we observe?” Abigail Bickley, PAN 2008

33. The Detectors: LHCb • Large Hadron Collider beauty • Dimensions • 69ft long • 33ft high • 43ft wide • 5,600,000lbs • Cost: • $520M • Collaboration: • 650 people • 47 institutions • 14 countries Scientific Goal: specializes in the study of the slight asymmetry between matter and antimatter present in interactions of B-particles (particles containing the b quark). Understanding it should prove invaluable in answering the question: “Why is our Universe made of the matter we observe?” Abigail Bickley, PAN 2008

34. Data Rates and Volume 18.6miles 12.4miles 9.3miles 3miles • Raw Rate: • 150M sensors record data at 40M/s • Filtered Rate: • 100 collisions per sec • Annual Data: • 15PB = 15,000,000GB • 100,000 DVDs per year Abigail Bickley, PAN 2008

35. The Grid • Data access required for all collaborators • Geographically dispersed globally • The creation of a "virtual supercomputer" composed of a network of loosely-coupled computers, acting in concert to perform very large tasks. Abigail Bickley, PAN 2008

36. Countdown…. http://www.symmetrymagazine.org/breaking/2008/04/14/what-can-we-expect-from-the-lhc/ • June 16th, 2008: beam pipe completed • August 2008: beam injection into LHC • October 2008: beam circulation • December: first collisions???!!! Abigail Bickley, PAN 2008

37. Stay Tuned…. Abigail Bickley, PAN 2008

38. Resources • LHC Homepage • http://lhc.web.cern.ch/lhc/ • LHC Status & Schedule • http://www.lhcountdown.com/ • US LHC • http://www.uslhc.us/LHC_Science • LHC Safety • http://public.web.cern.ch/Public/en/LHC/Safety-en.html • CERN Web • http://public.web.cern.ch/Public/en/LHC/WhyLHC-en.html Abigail Bickley, PAN 2008