Taking a closer look at LHC
Major events for CERN.
1949 - During the European Cultural Conference at Lausanne, the French physicist and Nobel prize-winner Louis de Broglie proposes the creation of a European science laboratory.
1950 - At the 5th General Conference of UNESCO held in Florence, the American physicist and Nobel prize-winner Isidore Rabi puts forward a resolution, which is unanimously adopted, authorising the Director General of UNESCO, "to assist and encourage the formation and organization of regional centres and laboratories in order to increase and make more fruitful the international collaboration of scientists ...".
1952 - After two UNESCO Conferences are held on the subject, 11 European governments sign an agreement setting up a provisional ‘Conseil européen pour la Recherche nucléaire' (CERN). At a meeting of the CERN council in Amsterdam, a site near Geneva is selected for the planned laboratory.
1954 - The European Organization for Nuclear Research is formally created on 29 September.Its 12 founding members were Belgium, Britain, Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland and Yugoslavia. Austria and Spain join CERN in 1959 and 1961 respectively.Yugoslavia leaves the Organization in 1961 for financial reasons. Spain leaves the Organization in 1969 but rejoins in 1983. Finland and Poland join in 1991, Hungary in 1992, the Czech and Slovak Republics in 1993, and Bulgaria in 1999 bringing the number of Member States to 20.
1957 - The 600 MeV Synchrocyclotron, CERN's first accelerator, was built to provide beams for particle and nuclear physics experiments. It was subsequently used in nuclear physics, astrophysics and medical physics.
1959 - Proton Synchrotron (PS) -28 GeV- dedicated to particle physics accelerated protons for the first time in November 1959.
1963 - First bubble chamber pictures of neutrino interactions are taken. Neutrino physics benefits greatly from fast ejection of protons from the Synchrotron, which is achieved for the first time ever during May this year.
1965 - Agreement with French authorities is signed in September on extending the CERN site over the French border. In December, the Council approves the construction of the Intersecting Storage Rings (ISR) on this extension of the site.
1967 - CERN commissions one of the world's finest facilities for the study of very short-lived nuclei-the Isotope Separator On-line (ISOLDE). An agreement between CERN, France and Germany covers the construction of a 3.7 metre hydrogen bubble chamber equipped with the largest superconducting magnet in the world. During its working life from 1973 to 1984, the ‘Big European Bubble Chamber' (BEBC) takes over 6 million photographs.
1968 - CERN scientist Georges Charpak develops a gas-filled box known as a "multiwire proportional chamber" that counted particles one thousand times better than previous detectors.Georges Charpak is awarded the Nobel Prize for Physics in 1992 for this invention.
1971 - The Intersecting Storage Rings produced the first-ever proton-proton collisions, a precursor to CERN's colliding-beam projects.
1972 - A four ring 800 MeV Booster is completed to increase the injection energy of the PS. With the booster and a new Linac, which starts operation in 1978, the PS machine exceeds its design intensity by more than a thousand times.
1973 - CERN announces an experiment in its Gargamelle bubble chamber shows the existence of neutral currents, a major advance in understanding the particles of matter and how they interact. In particular, it gives strong support to the theory that attempts to unite our understanding of the weak force-governing such phenomena as radioactivity-with the familiar electromagnetic force.
1976 - The Super Proton Synchrotron, with a circumference of 7 km is built, providing beams to large experimental areas of CERN. Scientists using those beams in 1983 discover the two charged particles, called W, and their neutral counterpart Z. The Super Proton Synchrotron is now the last link in the chain providing beams for the Large Hadron Collider.
1978 - Experiments at CERN show how beam quality and intensity can be improved using the ‘stochastic cooling technique', enabling intense beams of antiprotons to be accelerated and stored.
1981 - Conversion of the SPS into a proton-antiproton collider and the building of two experimental areas (UA-1 and UA-2) where data from the collisions can be taken. From then on, the operation of the SPS is divided between this collider mode and fixed-target physics. The first proton-antiproton collisions at an energy of 2 x 270 GeV are seen in July 1981, a few months after the start-up of the new Antiproton Accumulator ring (AA), where stochastic cooling is applied to produce the antiproton beam.
1981 - The Member States authorise construction of the Large Electron-Positron collider (LEP) for an initial operating energy of 50 GeV per beam.
1983 - Scientists using beams from SPS discover the two charged particles, called W± and their neutral counterpart Z (the carriers of the weak nuclear force). These discoveries confirmed the Electroweak Theory.
1984 - Carlo Rubbia and Simon van der Meer receive the Nobel Prize for Physics for their experimental work on proton-antiproton collisions that culminated in the discovery of the W boson and Z boson at CERN in 1983.
1989 - The Large Electron-Positron collider (LEP) is the largest electron-positron accelerator ever built with a circumference of 27 km (16.8 miles). The excavation of the tunnel to house it was Europe's largest civil engineering project before the Channel Tunnel. Its experiments proved there are three generations of particles of matter. The four LEP detectors are ALEPH, DELPHI, L3 and OPAL. 1989: The determination of the number of light neutrino families is reached in LEP, operating on the Z boson peak.
1990 - CERN scientist Tim Berners-Lee invents the worldwide web to meet demands for information-sharing between scientists. Berners-Lee defined basic concepts like the URL, http and html and also wrote the first browser and server software.
1994 - The CERN governing Council approves construction of the Large Hadron Collider, the world's largest particle accelerator with an eventual project cost of 10 billion Swiss francs (€ 7,4 billion).
1995 - Team at CERN's Low Energy Antiproton Ring facility creates atoms of anti-hydrogen, the first time that anti-matter particles were brought together to make complete atoms (the first creation of antihydrogen atoms in the PS210 experiment), helping explain the universe's asymmetry between matter and anti-matter.
1996 - LEP is upgraded to run at the W pair production threshold of 163 GeV. Further upgrades will take LEP energy to 200 GeV by 1999.
1997 - After agreeing to provide significant financial contributions to the LHC, the USA becomes an observer at CERN Council.
1999 - The discovery of direct CP violation in the NA48 experiment.
2000 - LEP was closed in 2000, after running for 11 years, to allow for the construction of the Large Hadron Collider in the same tunnel. A final burst of excitement occurred a few months prior to the scheduled shut down when one collaboration reported findings of a Higgs boson signal; however, it was not enough evidence to keep LEP in operation.
2001 - The European DataGrid project (EDG) is launched two years after the idea was born in Annapolis, USA. The project tests a networking infrastructure for the future computing grid. The Grid must connect tens of thousands of computers worldwide to serve scientific projects like the LHC.
2002 - Two CERN experiments create and trap thousands of atoms of anti-matter in a "cold" state, meaning the atoms are slow-moving and can exist for long enough to be studied before they meet ordinary matter and annihilate.
2002 - The first octupole correction magnet is delivered. In addition to the 1232 main dipole magnets that will curve the trajectory of the protons and the 400 focussing quadrupoles, the LHC will be equipped with some 5000 corrector magnets. The last piece of LEP goes up to the surface. In 14 months of dismantling, 40000 tonnes of material were removed from the 27-kilometre tunnel.
2003 -2008 - The assembly of LHC machine and its detectors takes place. During this time period a long number of milestones will be achieved in many different fields (electronics, cryogenics, magnets, computing, superconductivity, engeneering, infrastructures...).
2003 - A record for backing up data on tapes is beaten with a rate transfer of 1.1 gigabytes per second over a period of several hours. That is equivalent to recording a whole film stored on DVD every four seconds.
A data transfer record is set. One terabyte of data was sent more than 10 000 km from CERN to California in just over an hour, at a rate of 2.38 gigabits per second. This is equivalent to sending 200 DVD films a quarter of the way around the world in an hour.
2004 - The European project EGEE (Enabling Grids for E-sciencE) is launched. Co-ordinated by CERN and financed by the European Commission, it aims at setting up an infrastructure for a world computing grid for science.
The SPS accelerator, which will have to feed the LHC, beats an intensity record with 50 thousand billion protons accelerated in its 7 kilometre loop.
2005 - The LHC Computing Grid, which must meet enormous storage and data-processing needs, reaches more than 100 centres in 31 countries. It is the largest international scientific computing grid.
A cryogenics unit cools to 1.8 kelvin (‑271.4°C) for the first time. This is the operating temperature of the LHC.
A new step toward the Computing Grid: For 10 days, eight data-processing centres transfer a continuous data flow, with a medium flow of 600 megabytes a second. Five hundred terabytes are transferred, which would require 250 years with a connection of 512 kilobits a second.
2006 - The new CERN Control Centre, which combines all the control rooms for the accelerators, the cryogenics and the technical infrastructure, starts operation. The LHC will be controlled from here.
2007 - The biometric control to access the LHC is being set up. An iris recognition system will ensure the security of the entrances to the accelerator with special vestibules.
2008 - The Large Hadron Collider starts up. Its experiments are expected to address questions such as what gives matter its mass, why nature prefers matter to anti-matter, and how matter evolved from the first instants of the universe's existence.
Nine days after it is switched on, the LHC is shut down because of overheating due to problems in the super-conducting cable connecting two cooling magnets. Repairs cost up to $30 million.
2009 - After restarting the Large Hadron Collider after more than a year of repairs, LHC sets new world record. CERN‟s Large Hadron Collider has become the world‟s highest energy particle accelerator, having accelerated its twin beams of protons to an energy of 1.18 TeV in the early hours of the morning. This exceeds the previous world record of 0.98 TeV, which had been held by the US Fermi National Accelerator Laboratory‟s Tevatron collider since 2001.
2010 - LHC sets new record. Two 3.5 TeV proton beams successfully circulated in the Large Hadron Collider for the first time. This is the highest energy yet achieved in a particle accelerator, and an important step on the way to the start of the LHC research programme.
Four days is all it took for the LHC operations team at CERN to complete the transition from protons to lead ions in the LHC. After extracting the final proton beam first collisions were recorded on 7 November.
The isolation of 38 atoms of antihydrogen.
2011 -Standard Model Higgs boson mass constrained to the range 115-130 GeV.In a seminar held at CERN On December 13th, the ATLAS and CMS experiments presented the status of their searches for the Standard Model Higgs boson.
Maintaining antihydrogen for over 15 minutes.
2012. LHC are running with a beam energy of 4 TeV. The strategy is to optimise LHC running to deliver the maximum possible amount of data in 2012 before the LHC goes into a long shutdown to prepare for higher energy running. The schedule is to run beams through to November. There will then be a long technical stop of around 20 months, with the LHC restarting close to its full design energy late in 2014 and operating for physics at the new high energy in early 2015.
A Particle consistent with Higgs boson. The ATLAS and CMS experiments see strong indications for the presence of a new particle, which could be the Higgs boson, in the mass region around 126 gigaelectronvolts (GeV).
The LHCb experiment discovered two excited states for the Λb beauty particle, and measured of one of the rarest processes so far observed in particle physics, the decay of a Bs meson into two muons. ALICE performed detailed studies of the quark-gluon plasma, the matter of the primordial universe, and measurements from the TOTEM experiment are giving insights on the structure of the proton and provide input to the analyses of the other LHC experiments.
There were also exciting results from the antimatter hall as ALPHA made the first spectroscopic measurements of antihydrogen; and CERN celebrated several anniversaries: the Proton Synchrotron Booster celebrated its 40th birthday and to mark 100 years of research in cosmic rays the laboratory welcomed the astronauts who placed the Alpha Magnetic Spectrometer on the International Space Station.
2013. LHC run for 4 weeks with p-Pb collisions Shutdown, before a Long Shutdown.
The Nobel prize in Physics 2013 was awarded to François Englert and Peter W. Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider."
2013/14. Long Shutdown (LS) for the whole accelerator complex (LS1) LS1 was started as the project for the repair of the magnet interconnects to allow operating LHC at 14 TeV cms.
2015. An important achievement with Run I data was the first observation (CMS + LHCb experiments) of the very rare decay of the B0s particle into two muon particles: B0→µ+µ−. These decays are studied as they could open a window to theories beyond the Standard Model, such as supersymmetry.
LHC experiments are back in business at a new record energy -13 TeV- almost double the collision energy of its first run. This marks the start of season 2 at the LHC, opening the way to new discoveries. The LHC will now run round the clock for the next three years.
CERN’s LHCb experiment reports observation of exotic pentaquark particles. The pentaquark is not just any new particle. It represents a way to aggregate quarks in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.
The LHC collides ions at new record energy. Colliding lead ions allows the LHC experiments to study a state of matter that existed shortly after the big bang, reaching a temperature of several trillion degrees.
CERN Director-General Rolf Heuer passes the baton to Fabiola Gianotti. Geneva, 18 December 2015: the 178th session of the CERN Council today saw the handover ceremony from Rolf Heuer, CERN1’s Director-General for the past seven years, to Fabiola Gianotti, who will take up her functions at the head of the Organization on 1 January 2016.
2016. Chicago sees floods of LHC data and new results at the ICHEP 2016 conference . Particle physicists are showcasing a wealth of brand new results from the Large Hadron Collider (LHC) experiments at CERN at the “ICHEP 2016”2 conference in Chicago. With a flood of new data, the experiment collaborations can now dive in and explore at the new energy frontier of 13 TeV, following last year’s first glimpse of physics at this unprecedented energy level. LHC collaborations are presenting more than 100 different new results, including many analyses based on newly taken 2016 data. In particular, the intriguing hint of a possible resonance at 750 GeV decaying into photon pairs, which caused considerable interest from the 2015 data, has not reappeared in the much larger 2016 data set and thus appears to be a statistical fluctuation.
The LHC MoEDAL experiment publishes its first paper on its search for magnetic monopoles. the MoEDAL experiment at CERN1 narrows the window of where to search for a hypothetical particle, the magnetic monopole. Over the last decades, experiments have been trying to find evidence for magnetic monopoles at accelerators, including at CERN’s Large Hadron Collider. Such particles were first predicted by physicist Paul Dirac in the 1930s but have never been observed so far.
CERN welcomes Romania as its twenty-second Member State. On Monday, 5 September 2016, the Romanian flag was raised in front of CERN for the first time, marking the country’s accession to Membership of the Organization.
16 Dec 2016 — Following the notification of the completion of its internal approval procedures, Slovenia will join Cyprus and Serbia as an Associate Member State
19 Dec 2016 — In a Nature paper, the ALPHA collaboration reports the first ever measurement on the optical spectrum of an antimatter atom.
2017. 16 Jan 2017: Official notification that India has ratified the Association Agreement with CERN today
28 April 2017, the LHC once again began circulating beams of protons, for the first time this year. This follows a 17-week-long extended technical stop. The aim for 2017 is to reach an integrated luminosity of 45 fb-1 and preferably go beyond.
6 July 2017, at the EPS Conference on High Energy Physics in Venice, the LHCb experiment at CERN’s Large Hadron Collider has reported the observation of Ξcc++(Xicc++) a new particle containing two charm quarks and one up quark.
12 October 2017, for eight hours, LHC was accelerating and colliding Xenon nuclei, allowing the large LHC experiments, ATLAS, ALICE, CMS and LHCb, to record xenon collisions for the first time.
— In October 2017 the CERN data centre broke its own record for data storage when it collected 12.3 petabytes of data over a single month.
— CERN celebrates 25 years since the beginning of the LHC experimental programme
2018.— CERN has been officially notified that Lithuania's internal procedures have been approved, following the Agreement signed in June 2017
— After two decades of design and construction, CERN’s newest accelerator, Linac4, is on its way to join the LHC injection chain
19 Mar 2018 — ATLAS and CMS present new measurements of the properties of the Higgs boson in Moriond Conference (10 and 24 March 2018 in La Thuile in the Aosta Valley in Italy).
4 April 2018. The ALPHA collaboration has reported the most precise direct measurement of antimatter ever made, revealing the spectral structure of the antihydrogen atom in unprecedented colour. The result, published today in Nature, is the culmination of three decades of research and development at CERN, and opens a completely new era of high-precision tests between matter and antimatter.
25 July 2018, for the very first time, operators injected not just atomic nuclei but lead “atoms” containing a single electron into the LHC. This was one of the first proof-of-principle tests for a new idea called the Gamma Factory, part of CERN’s Physics Beyond Colliders project.
October 24th, protons performed their last lap of the track. At 6 a.m., the beams from fill number 7334 were ejected towards the beam dumps. It was the LHC’s last proton run from now until 2021, as CERN’s accelerator complex will be shut down from 10 December to undergo a full renovation. For the next weeks the collider will master lead ions (lead atoms that have been ionised, meaning they have had their electrons removed). The collisions of lead ions allow studies to be conducted on quark-gluon plasma, a state of matter that is thought to have existed a few millionths of a second after the Big Bang.
(*) For the bibliography used when writing this Section please go to the References Section
Xabier Cid Vidal, PhD in experimental Particle Physics for Santiago University (USC). Research Fellow in experimental Particle Physics at CERN from January 2013 to Decembre 2015. Currently, he is in USC Particle Physics Department ("Ramon y Cajal", Spanish Postdoctoral Senior Grants).
Ramon Cid Manzano, secondary school Physics Teacher at IES de SAR (Santiago - Spain), and part-time Lecturer (Profesor Asociado) in Faculty of Education at the University of Santiago (Spain). He has a Degree in Physics and in Chemistry, and is PhD for Santiago University (USC).
CERN and the Environment
For the bibliography used when writing this Section please go to the References Section