The ATLAS Collaboration submits the technical proposal of the experiment to the LHC Experiments Committee. Approval to proceed with technical design reports would be granted in early 1996, followed by the submission of the first report on 15 December of the same year. A long series of Technical Design Reports follow.
The first prototype bending-magnet for the LHC reaches a field of 8.73 Tesla, which is higher than the 8.4 Tesla field at which the LHC will operate in 2012.
Superconducting magnets must be "trained" so that they can maintain the superconducting state necessary to achieve such high fields. Any abnormal termination of the superconducting state, which switches the magnet back to its normal, resistive state, is called a "quench."
LHC Director Lyn Evans receives a hand-written note as he sits in a Finance Committee meeting. It reads:
Message de J.P Goubier et R.Perin à L Evans
on a attaint 8,73 tesla
They mean "sans quench" - a pun on the French word "cent" or "one hundred", which is pronounced the same as the word for "without".
On 3 December 1993, the Akeno Giant Air Shower Array (AGASA) recorded a cosmic ray with an energy of 2x1020 eV. This was a particularly well-measured event because the cosmic rays fell completely inside the detector array and arrived from a nearly vertical direction. This was the highest energy cosmic ray observed at AGASA and greatly exceeded that of any known source.
AGASA consists of 111 particle detectors dispersed about a kilometer apart over a 100 square kilometer area. Each detector is roughly 2.2 square kilometers in size. AGASA was completed in 1991 and has been measuring cosmic rays ever since.
Due to concerns linked to rising costs, the US government votes to cancel the Superconducting Super Collider project. The LHC becomes the sole candidate for a new high-energy hadron collider.
The Czech Republic joins
Statement of the government of the Czech Republic on questions of membership in International Governmental Organizations:
In connection with the dissolution of the Czech and Slovak Federal Republic on December 31, 1992, the Government of the Czech Republic declares the interest of the Czech Republic to be, after January 1, 1993, a fully-fledged member of the following international governmental organizations in the activities of which it has so far participated within the membership of the Czech and Slovak Federal Republic: [CERN is listed along with 51 other international organizations.]
The Czech Republic joined CERN as a member state on 1 July 1993.
The Slovak Republic joins
From CERN council minutes, 17 March 1993:
At its 297th meeting on 17 March 1993 Committee of Council discussed the accession of the Slovak Republic. Delegations indicated their unanimous support for the proposal of the accession.
The Slovak Republic joined CERN as a member state on 1 July 1993.
On 30 April 1993 CERN issued a statement putting the Web into the public domain, ensuring that it would remain an open standard. The organization released the source code of Berners-Lee's hypertext project, WorldWideWeb, into the public domain the same day. WorldWideWeb became free software, available to all. The move had an immediate effect on the spread of the web. By late 1993 there are over 500 known web servers, and the web accounts for 1% of internet traffic.
Berners-Lee moved to the Massachusetts Institute of Technology (MIT), from where he still runs the World Wide Web Consortium (W3C). By the end of 1994, the Web had 10,000 servers - of which 2000 were commercial - and 10 million users. Traffic was equivalent to shipping the collected works of Shakespeare every second.
The collaboration for A Large Ion Collider Experiment (ALICE) propose to build a detector at the LHC to study heavy-ion collisions. The letter of intent marks the first official use of the name ALICE.
By a letter dated 16 December 1992, the Permanent Mission of the Czech and Slovak Federal Republic (CSFR) to the United Nations in Geneva informed CERN that the Czech and Slovak Federal Republic would cease to exist on 31 December 1992 and that two new states – the Czech Republic and the Slovak Republic – would succeed it as from 1 January 1993.
The letter states:
It is the understanding, readiness and agreement of the both (sic) Czech and Slovak Republics that they will smoothly assume the total obligations of the CSFR with CERN after December 31, 1992 – develop the (sic) cooperation with CERN practically under the same conditions as the CSFR – and become full-fledged members of CERN.
The Toroidal LHC Apparatus collaboration propose to build a multipurpose detector at the LHC. The letter of intent they submit to the LHC Experiments Committee marks the first official use of the name ATLAS. Two collaborations called ASCOT and EAGLE combine to form ATLAS.
The Compact Muon Solenoid (CMS) collaboration proposes to build a multipurpose detector at the LHC. The letter of intent they submit to the LHC Experiments Committee marks the first official use of the name CMS.
The ATLAS Collaboration proposes the construction of a general-purpose detector at the Large Hadron Collider. The Letter of Intent was submitted to the LHC Experiments Committee, which marked the first official use of the name ATLAS. The Letter identified a number of conceptual and technical design options, including a superconducting toroid magnet system.
Hungary joined CERN in 1992, but Hungarian groups have participated in numerous experiments at CERN almost since its foundation. From the beginning, these collaborations were coordinated by the KFKI Research Institute for Particle and Nuclear Physics (RMKI) of the Hungarian Academy of Sciences, with the participation of physicists and engineers of the Institute of Nuclear Research (ATOMKI) of the Hungarian Academy of Sciences, of the Institute of Experimental Physics of the University of Debrecen, and of the Departments of Atomic and Theoretical Physics of Loránd Eötvös University in Budapest. High-energy physics thus has two centres in Hungary: Budapest and Debrecen, and their researchers form joint groups in all related activities. Hungarian research groups have contributed to many experiments at the Super Proton Synchrotron and the Large Electron-Positron collider.
Today, Hungarian participation in CERN concentrates on high-energy proton-proton and heavy-ion collisions in the framework of the CMS, ALICE and TOTEM collaborations at the LHC. Hungarian physicists are also involved in testing matter-antimatter symmetry in the ASACUSA experiment at the CERN Antiproton Decelerator. An important asset for the experimental activities is the Budapest site of the LHC Computing Grid system located at RMKI, which is to serve as the Tier-2 centre for Hungarian high-energy physics and also for other, interdisciplinary applications.
The Czech and Slovak Federal Republic
From council minutes on 20 December 1991:
In June 1991 the Director-General informed the Scientific Policy Committee and the Committee of Council of the wish of the Czech and Slovak Federal Republic to accede to CERN. Subsequently, in a letter dated 29 August 1991, the Czechoslovak Deputy Prime Minister and Minister of Foreign Affairs formally requested that the Czech and Slovak Federal Republic become a Member State of the Organization.
This letter was communicated to the Delegations by the President of Council on 10 September 1991. Official negotiations were conducted on 25 October 1991 and resulted in an "Aide-Mémoire", dated 25 October 1991, between CERN and the Czech and Slovak Federal Republic. At its 203rd meeting on 18 and 19 December 1991 the Committee of Council considered the document and decided to recommend to Council the terms and conditions for the accession of the Czech and Slovak Federal Republic.
The Czech and Slovak Federal Republic joined CERN as a member state on 1 July 1992.
First experiment at the ISOLDE Proton-Synchrotron Booster.
The first experiment was carried out on June 26, where the beta-proton decay of the neon isotope with mass number 17 was studied. This experiment was relevant for the understanding of nuclear halo structure, first proposed at ISOLDE.
The new ISOLDE PSB Facility has two isotope separators, a general-purpose separator with one magnet (GPS) and a high-resolution separator with two magnets, similar to the ISOLDE III design. The target handling in the facility is fully automatized with robots.
The first web server outside of Europe was installed on 12 December 1991 at the Stanford Linear Accelerator Center (SLAC) in California. In 1993, the National Center for Supercomputing Applications (NCSA) at the University of Illinois released its Mosaic browser, which was easy to run and install on ordinary PCs and Macintosh computers. The steady trickle of new websites became a flood. The world’s First International World-Wide Web conference, held at CERN in May, was hailed as the “Woodstock of the web”.
The Fly's Eye Mirrors (Image: Courtesy of University of Utah)
On 15 October 1991 the HiRes Fly's Eye cosmic-ray detector in Utah, US, recorded the highest-energy cosmic ray ever detected. Located in the desert in Dugway Proving Grounds 120 kilometres southwest of Salt Lake City, the Fly's Eye detects cosmic rays by observing the light that they cause when they strike the atmosphere.
Cosmic rays are mainly (89%) protons – nuclei of hydrogen, the lightest and most common element in the universe – but they also include nuclei of helium (10%) and heavier nuclei (1%), all the way up to uranium. When they arrive at Earth, they collide with the nuclei of atoms in the upper atmosphere, creating more particles, which start a cascade of charged particles that can produce light as they fly through the atmosphere.
The charged particles of a cosmic ray air shower travel together at very nearly the speed of light, so the Utah detectors see a fluorescent spot move rapidly along a line through the atmosphere. By measuring how much light comes from each stage of the air shower, one can infer not only the energy of the cosmic ray but also whether it was more likely a simple proton or a heavier nucleus. The Utah researchers measured the energy of the unusual cosmic ray event in 1991 to be 3.2x1020 eV.
On 15 October 1991 the Fly's Eye cosmic-ray detector in Utah, US, recorded the highest-energy cosmic ray ever detected. Located in the desert in Dugway Proving Grounds 120 kilometres southwest of Salt Lake City, the Fly's Eye detects cosmic rays by observing the light that they cause when they strike the atmosphere.
Cosmic rays are mainly (89%) protons – nuclei of hydrogen, the lightest and most common element in the universe – but they also include nuclei of helium (10%) and heavier nuclei (1%), all the way up to uranium. When they arrive at Earth, they collide with the nuclei of atoms in the upper atmosphere, creating more particles, which start a cascade of charged particles that can produce light as they fly through the atmosphere.
The charged particles of a cosmic ray air shower travel together at very nearly the speed of light, so the Utah detectors see a fluorescent spot move rapidly along a line through the atmosphere. By measuring how much light comes from each stage of the air shower, one can infer not only the energy of the cosmic ray but also whether it was more likely a simple proton or a heavier nucleus. The Utah researchers measured the energy of the unusual cosmic ray event in 1991 to be 3.2 × 1020 electronvolts (eV).
On 6 August 1991, Tim Berners-Lee posted a summary of the World Wide Web project on several internet newsgroups, including alt.hypertext, which was for hypertext enthusiasts. The move marked the debut of the web as a publicly available service on the internet.
The first contacts between Poland and CERN were established in 1959 when several scholarships were awarded to young Polish physicists from Cracow and Warsaw. This soon developed into a wider collaboration between CERN and Polish institutes. In 1964 Poland became an observer state at CERN, the only country from Eastern Europe to accede to this status. In 1991, Poland became the 16th member of CERN, and thus the first member state from the former Eastern block.
Today, high-energy physics in Poland is concentrated in six higher educational establishments and two research institutes. The biggest groups are active in Cracow and Warsaw. Polish groups have a widely recognized technical experience and good computing resources, and are well integrated in the international particle and astroparticle physics community. Strong groups participate in all LHC experiments building important parts of the equipment, such as radiation resistant silicon detectors and electronics for the inner tracking detector in the ATLAS experiment, electronics for the muon trigger in the CMS detector, straw trackers for the LHCb Outer Detector, and contributions to the lead-tungstate crystals for the photon spectrometer (PHOS) on the ALICE detector.
More than 100 Polish engineers and technicians from Cracow and Wroclaw participated in the commissioning of the LHC. Polish industry was also involved in the construction of the LHC and its experiments.
In 1991, an early WWW system was released to the high-energy-physics community via the CERN program library. It included the simple browser, web server software and a library, implementing the essential functions for developers to build their own software. A wide range of universities and research laboratories started to use it. A little later it was made generally available via the internet, especially to the community of people working on hypertext systems.
On 1 January 1991, Finland joined CERN as the organization's 15th member state. The Finnish government ratified the CERN convention and deposited the formal accession papers with the Director-General of UNESCO on 28 December 1990. On 28 January 1991 a full delegation of Finnish politicians and scientists came to Geneva to celebrate the official hoisting of the Finnish flag in front of the CERN entrance. The Finnish delegation was led by Jaakko Numminen, Secretary-General of the Finnish Ministry of Education and Science, and Antti Hynninen, Finnish Ambassador to the United Nations.
Finland has a long-standing tradition of research in theoretical high-energy physics. Since the beginning of the 1980s, experimental research has focused on key experiments at the high-energy frontier. These activities range from the UA1 experiment at the CERN proton-antiproton collider, the DELPHI experiment at LEP and the CDF experiment at the Fermilab Tevatron to significant contributions to three LHC experiments: ALICE, CMS and TOTEM. In parallel, Finnish research groups participate in experiments at the ISOLDE facility. It was therefore logical that Finland joined CERN as a member state in 1991.
Present and future experimental activities are based on four cornerstones: the Helsinki Institute of Physics, which coordinates experimental HEP activities in Finland; a good laboratory infrastructure for semiconductor and gas detector construction and development; a strong local link between phenomenology and experiment, especially in the fields of new physics and quantum chromodynamics; and a good university education system. With the exception of CDF, all experimental and a large part of the phenomenological research are linked to CERN activities.
The highest priority of the Finnish high-energy-physics community is a successful completion of the approved Large Hadron Collider (LHC) programme. In parallel, it pursues a strong interest in a physics programme with a high-luminosity upgrade of the LHC, and post-LHC facilities such as a linear electron-positron collider or a neutrino factory.
By Christmas 1990, Berners-Lee had defined the Web’s basic concepts, the URL, http and html, and he had written the first browser and server software. Info.cern.ch was the address of the world's first website and web server, running on a NeXT computer at CERN. The world's first web page address was http://info.cern.ch/hypertext/WWW/TheProject.html, which centred on information regarding the WWW project. Visitors could learn more about hypertext, technical details for creating their own webpage, and even an explanation on how to search the Web for information. There are no screenshots of this original page and, in any case, changes were made daily to the information available on the page as the WWW project developed. You may find a later copy (1992) on the World Wide Web Consortium website.
You can see the orginal NeXT computer at the Microcosm exhibit at CERN, still bearing the label, hand-written in red ink: "This machine is a server. DO NOT POWER DOWN!!"
On 19 December 1990, at noon, the beam from the Synchrocyclotron (SC) is stopped. At the end of the eighties the decision was taken to shut down the SC.
The ISOLDE programme should, however, continue at CERN and new facility will be built for an external beam from the Proton Synchrotron Booster.
(image: The basic principle of the RILIS technique: Two laser beams tuned to transitions between atomic levels - blue and yellow arrows - excite the atoms and a third beam induces the ionization)
The traditional ion sources used at ISOLDE were based on surface ionization and ionization in a plasma. These techniques together with different target matrices gave a large variety of beams for more than 20 years. A major step in improving the purity of and the number of available elements came in 1989 with a new technique based on laser ionization.
A combination of laser beams at wavelengths tuned to the sequence of atomic transitions enables highly efficient resonance excitation and ionization of selected atoms. Isotopes of other elements of the same mass do not interact with the laser radiation. This type of ion source is referred to as a Resonance Ionization Laser Ion Source (RILIS) and is a very powerful tool for the efficient and selective production of radioactive ion beams. The initial off-line RILIS development is then followed by its successful on-line application for laser ionization of ytterbium isotopes at ISOLDE-III on 10 October 1990.
This photo was taken on 13 November 1989 at the inauguration of the Large Electron-Positron (LEP) collider. From the left, Princess Margriet of the Netherlands, King Carl Gustav of Sweden, CERN Council President Josef Rembser, President Francois Mitterand of France, President Jean-Pascal Delamuraz of Switzerland, Carlo Rubbia, Director-General of CERN at the time.
The OPAL experiment recorded the very first collision at about five past midnight on 13 August 1989 and the other three experiments followed soon after. The first fully-fledged physics run began on 20 September and continued for three months. During this time, the experiments each recorded around 30,000 Z particles, enough for the first data analysis to get under way.
By the time LEP was officially inaugurated on 13 November 1989, in the presence of some 1500 guests including heads of state and ministers from all of CERN’s Member States, the first results had already been announced – the experiments had confirmed that only three types of neutrinos exist, and hence only three generations of matter particles.
With its 27-kilometre circumference, the Large Electron-Positron (LEP) collider was – and still is – the largest electron-positron accelerator ever built. LEP consisted of 5176 magnets and 128 accelerating cavities. CERN’s accelerator complex provided the particles and four enormous detectors, ALEPH, DELPHI, L3 and OPAL, observed the collisions.
LEP was commissioned in July 1989 and the first beam circulated in the collider on 14 July. The picture above shows physicists grouped around a screen in the LEP control room at the moment of start-up. Carlo Rubbia, Director-General of CERN at the time, is in the centre and former Director-General Herwig Schopper is on his left. For seven years, the accelerator operated at 100 GeV, producing 17 million Z particles, uncharged carriers of the weak force. It was then upgraded for a second operation phase, with as many as 288 superconducting accelerating cavities added to double the energy and produce W bosons, also carriers of the weak force. LEP collider energy eventually topped 209 GeV in the year 2000.
During 11 years of research, LEP and its experiments provided a detailed study of the electroweak interaction based on solid experimental foundations. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the LHC in the same tunnel.
Astrophysicists detected pulsed gamma-ray emissions from the Crab pulsar with energies that exceed 100 billion electronvolts (GeV). A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The Whipple Observatory 10-metre reflector, operating a 37-pixel camera, was used to observe the Crab Nebula in TeV gamma rays. The paper announcing their finding was published on July 1 1989.
The Crab pulsar is a rapidly spinning neutron star that exploded in a supernova in the year 1054 to leave behind the Crab Nebula. The Nebula rotates at about 30 times a second and the pulsar has a co-rotating magnetic field from which it emits beams of radiation.
Read more: "Observation of TeV gamma rays from the Crab nebula using the atmospheric Cerenkov imaging technique" – Astrophysical Journal, Part 1, 342 (1989) 379-395
In March 1989, CERN scientist Tim Berners-Lee wrote a proposal to develop a distributed information system for the laboratory. “Vague, but exciting” was the comment that his supervisor, Mike Sendall, wrote on the cover, and with those words, gave the green light to an information revolution.
Tim Berners-Lee made a first proposal for information management at CERN in March 1989 (no exact date is given). A later version was written in 1990, but this early document is particularly interesting because it includes annotations by his boss, Mike Sendall, whose general comment was ‘Vague but exciting…’! The project eventually grew to become the World Wide Web.
In this document Berners-Lee outlined the problems of losing information at CERN, the advantages of linked information and hypertext and the practical requirements of his idea. He proposed ‘a universal linked information system, in which generality and portability are more important than fancy graphics techniques and complex extra facilities. The aim of the project would be to allow a place to be found for putting any information or reference which one felt was important, and a way of finding it afterwards.’ With the help of Robert Cailliau and others he was able to make the dream a reality.
The excavation of the tunnel for the Large Electron-Positron Collider – Europe’s largest civil-engineering project prior to the Channel Tunnel – is completed on 8 February 1988. The two ends of the 27-kilometre ring come together with just one centimetre of error. The picture above shows a tunneling crew after completing a section of the tunnel between points 2 and 3 on the LEP ring.
With US President Ronald Reagan’s support, American physicists begin in-depth preparations to build the largest particle collider ever. The Superconducting Super Collider (SSC) – a circular accelerator with an 87-kilometre circumference – is designed to smash particles together at 40 TeV centre-of-mass energy. This would make the accelerator far more powerful than CERN's planned Large Hadron Collider (LHC). Construction begins in 1991 near Waxahachie, Texas. To some, the existence of the SSC project puts the need to build the LHC into doubt. Director-General Carlo Rubbia has to push to keep the LHC project alive.
Just after the big bang the universe was too hot and dense for the existence of familiar particles such as protons and neutrons. Instead, their constituents – the quarks and gluons – roamed freely in a "particle soup" called quark-gluon plasma.
In 1986 CERN began to accelerate heavy ions – nuclei containing many neutrons and protons – in the Super Proton Synchrotron (SPS) to study the possibility that quark gluon-plasma was more than just a theory. The aim was to "deconfine" quarks – set them free from their confinement within atoms - by smashing the heavy ions into appropriate targets.
The first experiments used relatively light nuclei such as oxygen and sulphur, and produced results consistent with the quark-gluon plasma theory, but no real proof. In 1994 a second generation of experiments began with lead ions, and by 2000 there was compelling evidence that a new state of matter had been seen.
Portugal joined CERN as a member state in 1986. The Laboratório de Instrumentação e Física Experimental de Partículas (LIP) was created at the same time to carry out all activities related to experimental particle physics, involving researchers from universities as well as LIP’s own scientific staff.
LIP's commitment to CERN programmes is presently based on LHC experiments and technologies (ATLAS, CMS and LCG), and the COMPASS collaboration. The Portuguese Institute for Nuclear Technologies (ITN) is leading the activity of a research team using the CERN ISOLDE facility.
The discovery of the W boson is so important that the two key physicists behind the discovery receive the Nobel prize in physics in 1984. The prize goes to Carlo Rubbia (pictured, left), instigator of the accelerator’s conversion and spokesperson of the UA1 experiment, and to Simon van der Meer (pictured, right), whose technology is vital to the collider’s operation.
The discovery of the W boson is a significant achievement in physics that further validates the electroweak theory. It also helps to secure the decision to build CERN’s next big accelerator, the Large Electron Positron Collider, whose job is to mass-produce Z and W bosons for further studies.
CERN and the European Committee for Future Accelerators (ECFA) hold a workshop in Lausanne, Switzerland and at CERN from the 21-27 March 1984. The event, Large Hadron Collider in the LEP Tunnel, marks the first official recognition of the concept of the LHC. Attendees consider topics such as what types of particles to collide and the challenges inherent to high-energy collisions. The image above shows one proposal from the workshop – adding the LHC in with the existing LEP machine – that was later scrapped.
CERN staff and their families were joined by numerous distinguished guests for the official ceremony that launched civil engineering work for the Large Electron-Positron (LEP) collider project on 13 September 1983. Speeches by Herwig Schopper (CERN’s Director-General) and Presidents François Mitterrand and Pierre Aubert were followed by an inaugural ceremony, then music and celebrations on the lawn.
With a circumference of 27 kilometres, LEP was the largest electron-positron accelerator ever built, and excavation of the LEP tunnel was Europe's largest civil-engineering project prior to the Channel Tunnel. LEP operated for 11 years from July 1989 until its closure on 2 November 2000 to make way for construction of the Large Hadron Collider (LHC) in the same tunnel.
The presidents of CERN’s two host countries, François Mitterrand of France and Pierre Aubert of Switzerland, symbolically broke the ground and laid a plaque commemorating the inauguration of the Large Electron-Positron collider (LEP) on 13 September 1983.
Although much of the necessary infrastructure for the new accelerator was already in place (such as CERN’s existing accelerator complex to pre-accelerate the electrons and positrons for LEP), many new facilities were needed. The most obvious of these was the 27-kilometre tunnel that housed the machine, along with the experimental halls and surface buildings. Transfer tunnels joining the Super Proton Synchrotron to LEP were also needed, as were buildings to house a linear accelerator (linac) and storage rings to make and accumulate electrons and positrons. Despite the huge scale of the undertaking, progress was impressive. By the end of 1984, the buildings for the linac and the electron-positron accumulator were complete and 10 of the 18 access shafts had been excavated.
CERN is a centre for scientific research, but also a place for exchanges between science and other fields of human culture and understanding. The visit of His Holiness the Dalai Lama on 30 August 1983 provided just such an opportunity. In the morning he and his delegation of monks toured some of CERN’s facilities, including UA1, where the recent discovery of the W and Z bosons had taken place. After joining the visitors for lunch, some of CERN’s physicists gave short presentations on various aspects of CERN’s work, and a discussion explored the different viewpoints of Buddhists and physicists on a range of topics of mutual interest.
To maximize the use of the Synchrocyclotron (SC) beam time and to meet the requests from the growing physics community using ISOLDE, the ISOLDE collaboration decides to build a second isotope separator of ultra-modern design. The separator design uses a two-stage separation (one 60 degree and one 90 degree magnet) in order to obtain a very high resolution. The target is placed in the SC vault and after the second magnet, the ion beam enters the proton hall, which serves as the new experimental area.
ISOLDE III, is approved at the CERN Research Board session in June 1983 and the final approval to start building the new separator is taken on 10 November of the same year.
In a press conference on 25 January, CERN announces news of the discovery of the W boson to the world. The UA2 team reserves judgment at this stage but further analysis soon convinces them. From their results both teams estimate the boson's mass at around 80 GeV, which is in excellent agreement with predictions from electroweak theory.
In 1979, CERN decided to convert the Super Proton Synchrotron (SPS) into a proton–antiproton collider. A technique called stochastic cooling was vital to the project's success as it allowed enough antiprotons to be collected to make a beam.
The first proton–antiproton collisions were achieved just two years after the project was approved, and two experiments, UA1 and UA2, started to search the collision debris for signs of W and Z particles, carriers of the weak interaction between particles.
In 1983, CERN announced the discovery of the W and Z particles.The image above shows the the first detection of a Z0 particle, as seen by the UA1 experiment on 30 April 1983. The Z0 itself decays very quickly so cannot be seen, but an electron-proton pair produced in the decay appear in blue. UA1 observed proton-antiproton collisions on the SPS between 1981 and 1993 to look for the Z and W bosons, which mediate the weak fundamental force.
Carlo Rubbia and Simon van der Meer, key scientists behind the work, received the Nobel Prize in physics only a year after the discovery. Rubbia instigated conversion of the SPS accelerator into a proton-antiproton collider and was spokesperson of the UA1 experiment while Van der Meer invented the stochastic cooling technique vital to the collider’s operation.
The tension at CERN becomes electric, culminating in two seminars, from Carlo Rubbia (for UA1) on 20 January 1983 and Luigi Di Lella (for UA2) the following afternoon, both with the CERN auditorium packed to the roof. UA1 announces six candidate W events; UA2 announces four. The presentations are still tentative and qualified.
At the Topical Workshop on Proton-Antiproton Collider Physics in Rome from 12-14 January 1983, the first tentative evidence for observations of the W particle by the UA1 and UA2 collaborations is presented.
Out of the several thousand million collisions recorded, a handful give signals, which could correspond to the production of a W in the high-energy collision and its subsequent decay into an electron (or positron if the W is positively charged) and a neutrino
The return to CERN as a member state in 1983 marked the renaissance of high-energy physics in Spain. In the same year, a special programme for particle physics was created within the framework of the Spanish National Plan for research and development. The continuation of the original programme serves today to coordinate and fund most of the experimental and theoretical particle and astroparticle physics research in Spain.
A substantial part of the experimental high-energy physics activities in Spain is carried out at research institutes. Centro de Investigaciones Energeticas Medioambientales y Teconologicas (CIEMAT) in Madrid, Institut de Fisica d'Altes Energies (IFAE) in Barcelona and Consejo Superior de Investigaciones Científicas (CSIC) in Valencia play leading roles in detector construction and research-and-development activities. This effort is complemented by the activities of several other university groups such as Santander, Santiago de Compostela and Zaragoza, and research centres. Additional support to all groups is provided by the National Centre for Particle, Astroparticle and Nuclear Physics (CPAN). Several theory groups are very active in particle physics, studying a wide range of topics from phenomenology to mathematical physics. Spain also actively participates in most European Grid activities.
Spanish industry has participated in the construction of the LHC and its detectors, and has benefitted from an important transfer of technologies from CERN to Spain.
The first person outside CERN to be informed of the imminent discovery of the W boson is Margaret Thatcher, then Prime Minister of the United Kingdom, who paid a visit to CERN in August 1982. [See a video of the visit]. During her visit Thatcher asked the then Director-General of CERN Herwig Schopper to keep her updated on the progress of the search for the carriers of the weak force, the W and Z bosons.
In a confidential letter dated 20 December 1982, Schopper wrote:
"I am ever mindful of the promise I made on the occasion of your visit to CERN…that I would report to you immediately and directly on the day CERN obtained confirmed experimental evidence of the 'intermediate boson' (W+, W- and Z0) for which we are actively searching. …I am…pleased to inform you, in strict confidence, that the results recently obtained point to the imminence of such a discovery…"
Carlo Rubbia delays his departure to the Lisbon High Energy Physics Conference by a day so that on 10 July 1981, he is able to announce that the UA1 detector has seen its first proton-antiproton collisions. UA2 takes its first data in December this same year.
The Super Proton Synchrotron (SPS) accelerates its first pulse of antiprotons to 270 GeV. Two days later, with a proton beam orbiting in the opposite direction, there is the first evidence of proton-antiproton collisions. In August, the antiproton count reaches 109 and the UA1 calorimeter records some 4000 events. In October, the first visual evidence of the collisions is recorded in the streamer chambers of the UA5 detector (a precursor to UA2).
In the late 1970s physicists from CERN member states were discussing the long-term future of high-energy physics in Europe. A new picture of fundamental processes – unification – was emerging and the Large Electron Positron collider (LEP) would be the machine to study it. After a history built on proton accelerators, the idea of an electron-positron collider was a break with tradition for CERN. But since the results of electron and positron collisions are far easier to interpret than collisions between protons and antiprotons (which were on CERN’s more immediate horizon with the UA1 and UA2 experiments), the LEP proposal won through.
Presenting the project to CERN council, CERN Director-General Herwig Schopper reviewed the scientific justifications, budget and construction timetable for LEP. He concluded that:
Very rarely in the past has there been so much unanimity and so much consensus amongst the European Scientific Community on the validity of a research instrument.
The accelerator was formally approved on 22 May 1981.
The Intersecting Storage Rings produced the world’s first proton-antiproton collisions on 4 April 1981, paving the way for proton-antiproton collisions in the Super Proton Synchrotron (SPS), and the Nobel prize for Simon van der Meer and Carlo Rubbia.
The ISR proved to be an excellent instrument for particle physics. By the time the machine closed down in 1984, it had produced many important results, including indications that protons contain smaller constituents, ultimately identified as quarks and gluons.
Proton beams are injected and stored for the first time in the Antiproton Accumulator – a storage ring invented by CERN physicist Simon van der Meer where stochastic cooling produces intense antiproton beams. It took only two years from authorization of the machine to the announcement of first operation at the International Accelerator Conference at CERN, in July 1980. Within days, magnet polarities are reversed and antiprotons are injected and cooled.
Three physicists, Steven Weinberg, Abdus Salam and Sheldon Glashow, receive the Nobel prize in physics for proposing the electroweak theory. They believe that two of the four fundamental forces – the electromagnetic force and the weak force – are in fact different facets of the same force. Under high-energy conditions such as those in a particle accelerator, the two would merge into the electroweak force. But three hypothetical force-carrier particles described by the theory have yet to be confirmed in experiments: the W+, W- and Z0 bosons. These are heavy particles; so finding them would require an accelerator that could reach an unprecedented level of energy.
Official 25th anniversary celebrations were held on 25 June, but the fun and games happened on CERN’s real birthday, 29 September. As well as sports, sideshows, films, and Genevan Pipes and Drums, there was Happy Birthday, CERN, written and recorded for the occasion at Fermilab.
Verse three goes like this:
“Here's the toast we're proposing:
may your future be greater,
And the budget imposing for your
May your staff be effective and
your beams full of pep,
May you gain your objective of
constructing the LEP!”
If you can bear to read more, scroll down to page four here - and take a look at one of one of the star attractions at the same time: the Fire Brigade’s 20-metre rescue chute.
CERN issues a press release announcing the first storage of antiprotons. It reads:
Antimatter, in the form of antiprotons, has been stored for the first time in history.
This scientific first occurred at CERN, the European Organisation for Nuclear Research, at the end of July during tests conducted in view of using the SPS European accelerator as a colliding device between protons and antiprotons.
Several hundred antiprotons of 2.1 GeV/c were produced by protons from the PS accelerator and were kept circulating in a machine called ICE (Intial Cooling Experiment) for a period of 85 hours i.e. about 300, 000 seconds (3 × 105). The previous best experimental measurement of antiproton lifetime, acquired during bubble chamber experiments, was about 10-4 second, i.e. a ten-thousandth of a second.
CERN physicist Carlo Rubbia pulls together a team to put forward a proposal for an experiment code-named UA1, for "Underground Area 1", since its location on the SPS requires a large cavern to be excavated. The team grows to involve some 130 physicists from 13 research centres – Aachen, Annecy LAPP, Birmingham, CERN, Helsinki, Queen Mary College London, Collège de France Paris, Riverside, Rome, Rutherford, Saclay, Vienna and Wisconsin. On 29 June 1978, the CERN Research Board accepts the proposal for a huge "general purpose" detector to record proton-antiproton collisions at 540 GeV.
On 7 may 1977 Europe inaugurated the world’s largest accelerator – the Super Proton Synchrotron; you can read all about it in the CERN Courier.
But what was happening behind the scenes? Did you know that organising secretary, Miss Steel, set up a massive card index to keep track of the guests, entering all the details on 6,000 colour-coded cards? She also insisted on sending reply cards to the VIPs, even though treating them like ordinary mortals was considered infra dig; she said the higher you go in a hierarchy, the less legible signatures become, and she wanted to know who the replies came from. Logistics were further complicated by differing conceptions between the different countries as to what constituted an “official delegate”. Her unofficial report makes interesting reading too.
At 2.2 kilometres in diameter the Super Proton Synchrotron is Europe's largest particle accelerator. Commissioning of the accelerator begins in mid-March 1976 using beams of protons. Then on 17 June 1976 the SPS accelerates a beam of protons at its design energy of 400 GeV for the first time. The machine is ready to supply beams to experiments.
At the International Neutrino Conference in Aachen, Germany, (8-12 June 1976) physicists Carlo Rubbia, Peter McIntyre and David Cline suggest modifying the Super Proton Synchrotron (SPS) from a one-beam accelerator into a two-beam collider. The two-beam configuration would collide a beam of protons with a beam of antiprotons, greatly increasing the available energy in comparison with a single beam colliding against a fixed target.
Their paper on the subject, Producing Massive Neutral Intermediate Vector Bosons with Existing Accelerators is published in the conference proceedings the following year.
The Super Proton Synchrotron (SPS) became the workhorse of CERN’s particle physics programme when it switched on in 1976. The first beam of protons circulated the full 7 kilometres of the accelerator on 3 May 1976. The picture above shows the SPS control room on 17 June 1976, when the machine accelerated protons to 400 GeV for the first time. Research using SPS beams has probed the inner structure of protons, investigated nature’s preference for matter over antimatter, looked for matter as it might have been in the first instants of the universe and searched for exotic forms of matter. A major highlight came in 1983 with the Nobel-prize-winning discovery of W and Z particles, with the SPS running as a proton-antiproton collider.
The SPS operates at up to 450 GeV. It has 1317 conventional (room-temperature) electromagnets, including 744 dipoles to bend the beams round the ring. The accelerator has handled many different kinds of particles: sulphur and oxygen nuclei, electrons, positrons, protons and antiprotons.
New experiments are installed at ISOLDE II and placed at the three main beam-lines. The photo shows the underground hall UR8 on April 6 1976, which only housed experimental installations. The control desk could be found one floor above.
A trip to China in September 1975 helped pave the way for increased contact between the scientific communities. Scientists from the People's Republic of China had visited CERN in July 1973, and the reciprocal invitation two years later included social and scientific exchanges plus the traditional group photo at the National People’s Congress Palace. The schedule underwent several changes, you can see a draft here.
The visitors assured their hosts that Chinese physicists and engineers would be welcome at CERN for longer periods. ”At first, their reaction was polite agreement as to the desirability of such visits,” reported Viktor Weisskopf. “On September 14, we were received by a high government official: Wu Lein-fu, Vice Chairman of the Standing Committee of the National Congress [centre front of photo]. This man supported the proposal of extended visits of Chinese physicists and engineers to CERN, by quoting a Chinese proverb: "One eye is better than a hundred ears”. I had the impression that, from then on, the Chinese physicists talked much more about extended visits to CERN." You can read more about it in the October 1975 issue of the CERN Courier.
A Data Handling Division report by Philipe Bloch states:
Around the CERN sites more than 150 computers of widely varying sizes are installed. They vary from small mini-computers (PDP8, HP2115A) via larger mini's and control computers (PDP11/45, HP4100, Nord-10, IBM1800, Modular One, Ferranti Argus 500) over medium sized computers such as PDP-10, IBM-360/44, CII 10070 and CDC 3200 to very large computers (CDC 6600, CDC 7600) in the Computer Centre itself. Many mini-computers are used by experimenters for data collection but accelerator control, remote batch stations and process control application use most of these. The medium sized computers are normally dedicated to particular types of processing for individual groups or divisions: measurements of bubble chamber pictures (CDC 3200, ERASME on the PDP-10), support for data collection for the OMEGA spectrometer and the Split Field Magent (CII 10070).
The Computer Centre is part of the Data Handling Division and provides a general purpose scientific computing service to both Laboratories... About 700-800 different users run approximately 15,000-20,000 jobs per week on the main computers and mount about 4000 tape reels from a total tape library of more than 6000 reels. Remote batch and terminal services as well as high-speed data links and a delivery service make computing easily accessible practically everywhere on the site round the clock.
A few months after the signature of the agreement giving the go-ahead for the expansion of CERN into French territory, work began on the Super Proton Synchrotron (SPS). Two years later, on 31 July 1974, the Robbins tunnel-boring machine excavating the SPS tunnel returned to its starting point (see photograph). It had excavated a tunnel with a circumference of 7 kilometres, at an average depth of 40 metres below the surface. The tunnel straddled the Franco-Swiss border, making the SPS the first cross-border accelerator. More than a thousand magnets were needed to equip the ring. The civil engineering and installation work was completed in record time after only four years.
A team photo celebrates the completion of the SPS tunnel in July 1974. The Super Proton Synchrotron (SPS) was the first of CERN’s giant accelerators. It was also the first cross-border accelerator. Excavation took around two years, and on 31 July 1974 the Robbins tunnel-boring machine returned to its starting point having crossed the Franco-Swiss border and excavated a tunnel with a circumference of 7 kilometres and an average depth of 40 metres below the surface.
The SPS was commissioned in 1976, and a highlight of its career came in 1983 with the announcement of the Nobel prize-winning discovery of W and Z particles.
(image: The ISOLDE II experimental area)
In March 1974, the SC improvement programme is completed and the first beams are directed towards the ISOLDE targets.
The intensity increase of the external beam up to 1 μA together with new target designs hold their promises and give a considerable increase in the number of isotopes available for experiments.
A new target design and a new layout of the isotope separator is implemented. The target-ion-source unit is placed in the proton beam and the magnet of the isotope separator is placed close to the target. The separated isotopes are then directed towards the experimental setups via a switchyard, which allows researchers to experiment with isotopes of different mass numbers simultaneously.
The first experiment at the reconstructed ISOLDE Facility was performed on March 11, where a target-ion-source system for production of neutron deficient Cs isotopes was used to detect combined beta-delayed proton and alpha emission for the neutron deficient Cs isotopes with mass numbers 118 and 120.
(image: The Synchrocyclotron with the rotating condenser )
The Synchrocyclotron (SC) is shut down for a major reconstruction in 1972, called the SC Improvement Programme (SCIP). An important part of the upgrade of the SC is to change the frequency system from one based on a tuning fork to a rotating condenser. The extraction system of the beam to ISOLDE is also improved, which means a beam intensity of about two orders higher can be delivered to the ISOLDE target.
Simon van der Meer at CERN writes a paper describing a technique he had first though of in 1968 to reduce the energy spread and angular divergence of a beam of charged particles. During this process of "stochastic cooling", the particles are "compressed" into a finer beam with less energy spread and less angular divergence. By increasing the particle density to close to the required energy, this technique improved the beam quality and, among other things, brings the discovery of the W boson within reach.
What is a computer? Why does CERN need the new ‘number crunchers’ anyway? These are some of the questions Lew Kowarski tries to answer in a special issue of the CERN Courier devoted to computing at CERN in 1972.
In his introduction he explains that high-energy physics is not just about hunting down and photographing strange particles, as though they were so many rare animals. Other articles give details of electronics experiments, bubble chamber experiments, data acquisition and analysis, mathematical computing applications in theoretical studies and more. But it is perhaps the advertisements that really capture the state of the art nearly half a century ago.
A “modest ceremony” marked the opening of a new training centre for CERN’s apprentices in December 1971. The converted barrack was fitted with a range of equipment, enabling them to practice their skills and spend more time learning together before heading around the laboratory for further training.
The apprenticeship programme had been set up in conjunction with the Geneva authorities to take advantage of the extraordinary range of specialist skills found at CERN. It began in 1966 with the enrolment of five young people, two in design office work, one as a laboratory assistant and two in administration. Starting at around the age of 15, they spent three or four years at CERN before moving on to further education or directly into employment.
The Super Proton Synchrotron is designed to provide protons at 400 GeV for fixed-target experiments. Construction for this underground synchrotron begins on 19 February 1971.
Seven kilometres in circumference, the Super Proton Synchrotron (SPS) was the first of CERN’s giant underground rings. It was also the first accelerator to cross the Franco–Swiss border.
Eleven of CERN's member states approved the construction of the SPS in February 1971, and it was switched on for the first time on 17 June 1976, two years ahead of schedule. The SPS quickly became the workhorse of CERN’s particle physics programme, providing beams to two large experimental areas. Advances in technology during the building period meant that not only was construction finished early, it was able to operate with a beam energy of 400 GeV - 100 GeV higher than the original design energy.
The SPS operates today at up to 450 GeV, and has handled many different kinds of particles. Research using SPS beams has probed the inner structure of protons, investigated nature’s preference for matter over antimatter, looked for matter as it might have been in the first instants of the universe and searched for exotic forms of matter.
By the late 1950s, physicists knew that a huge gain in collision energy would come from colliding particle beams head on, rather than by using a single beam and a stationary target. At CERN, accelerator experts conceived the idea to use the Proton Synchrotron (PS) to feed two interconnected rings where two intense proton beams could be built up and then made to collide. The project for the Intersecting Storage Rings (ISR) was formally approved in 1965.
On 27 January 1971 Kjell Johnsen (pictured), who led the construction team for the Intersecting Storage Rings (ISR), announced that the world's first interactions from colliding protons had been recorded. Pictured on the left are Franco Bonaudi, who was responsible for the civil engineering and Dirk Neet, who later took charge of ISR operations.
For the next 13 years the machine provided a unique view of the minuscule world of particle physics. It also allowed CERN to gain valuable knowledge and expertise for subsequent colliding-beam projects, and ultimately the Large Hadron Collider. For example, it was here that Simon van der Meer’s ideas to produce intense beams by a process called "stochastic cooling" were first demonstrated.
The scene is the control room of the Intersecting Storage Rings (ISR) on 27 January 1971. Kjell Johnsen, leader of the ISR construction team, has just announced successful recording of the first ever interactions from colliding proton beams. It was a triumphant moment, not least because the ISR had been an ambitious and highly controversial project, with several years of heated debate preceding its final unanimous approval by the CERN council in June 1965.
The interconnected rings, 300 metres in diameter and fed from the Proton Synchrotron (PS), ran from March 1971 until December 1983. At the official inauguration on 16 October 1871, Werner Heisenberg handed the President of the CERN council, Edoardo Amaldi, a golden key that controlled the transfer of protons from the PS to the ISR, symbolizing their hopes that the new machine would be the key to a thorough understanding of the world of elementary particle physics. He said such a symbolic key should first be in the hands of the experimentalists. At the closure ceremony on 26 June 1984, the key was formally handed back to the theorists, in the person of Viktor Weisskopf.
A new group set up at CERN in the 1970s had rather different objectives to those of the rest of the laboratory. Their main task was to build a 3.6 metre telescope to be sent to Chile, following signature of a collaboration agreement between the ESO and CERN on 16 September 1970.
The first meeting of the coordinating committee two years later reviewed progress and confirmed that ESO’s Sky Atlas Laboratory was also welcome to continue their work of mapping the southern sky at CERN. The groups relocated to the ESO’s new premises at Garching, Germany, in 1980. See the committee report, read the press release and Professor Blaauw’s article in the August 1970 CERN Courier, or enjoy some more photos of the teams at work.
Astronaut Rusty Schweickart’s visit to CERN on 4 June 1969 was a big hit. The auditorium was packed, and his talk on The Flight of Apollo 9 and the Future of Space Exploration was screened to other equally crowded rooms around CERN. Just three months earlier he had been the Lunar Module pilot on the Apollo 9 mission, which carried out a series of tests in earth orbit paving the way for the landing of the first man on the moon on 20 July. The Lunar Excursion Module was the small spacecraft that would separate from the parent capsule in lunar orbit to carry two astronauts down to the surface of the moon and back.
In the two days following Rusty’s talk a further 1,250 people watched the Apollo 9 film, and Rusty was able to return incognito for a good look round CERN. More photos and an audio recording of part of the question and answer session are available if you’d like to know more.
The CDC 6400 was upgraded to a CDC 6500 in 1969. This image, taken on 12 February 1974, shows a general view of the remote input/output station installed in building 112, used for submitting jobs to the CDC 6500 and 6600. The card reader on the left and the line printer on the right are operated by programmers on a self-service basis.
The Canton of Geneva bought the CDC 3800 from CERN, and installed it at the University of Geneva. At CERN, the CDC 3800 was replaced by a CDC 6400.
At the request of the Spanish government, Spanish contributions to the CERN budget for 1964, 1965 and 1966 were reduced by 50%, 35% and 20% respectively. In a letter on 21 September 1996 to the Director-General the government asked for a further reduction of 35% from 1967 onwards. The CERN finance committee rejected the request.
Minutes of the CERN council, 19-20 June, 1969:
At the 40th Session of council last year, Spain asked that her notice of withdrawal from the organization contained in her letters of 8 August and 30 October should be held in suspense whilst her authorities studied further the possibility of her remaining in CERN.
By letter of 2 June 1969, Spain notified the Director-General that no solution had been found possible and that consequently her withdrawal from the organization would take effect as from 31 December 1968.
The council is now invited to take note of the withdrawal of Spain from the organization.
Spain formally withdrew from CERN on 31 December 1968.
Summer at CERN means summer students – and a succession of distinguished speakers from within and outside the organization who share their knowledge with young scientists each year. This photo shows Nobel Prize-winner T. D. Lee explaining symmetry principles in physics to the 1968 intake.
The summer student programme was set up in 1962 as an extension of the existing fellows and visitors scheme. In its first year, 70 students were selected from around 500 applicants; they stayed for 6–8 weeks, lodging at the University in Geneva or in temporary barracks on the CERN site. Since then the programme has continued to grow, and the combination of work experience, lectures, discussions and workshops – and an active social life – remains just as popular.
Dialling zero for an outside line could be frustrating in 1965. With just 17 lines serving 1,000 CERN extensions, callers faced long waits – and if the overloaded battery failed no-one could got through at all. Phone traffic had increased by 70% between 1963 and 1965, complaints were frequent and the exchange staff were feeling overloaded too.
No more lines, extensions or operators’ desks could be added to existing exchange, so a new one was commissioned. Stop-gap measures until it was ready in August 1968 included pleas for patience and strict rationing of the only 140 new internal phone numbers remaining at CERN.
CERN’s internal magazine carried detailed instructions about closed roads, blocked entrances, and suggested detours. Staff were invited to respect the parking ban and to obey police instructions, but plenty of them took the opportunity to pile outside and watch as well. On 19 July 1968 the Tour de France came right past CERN’s main entrance!
CERN staff joined fans lining the route to encourage riders on Stage 20, which took the riders 242.5 km from Sallanches to Besançon, over the Faucille pass in the nearby Jura mountains. This was the last year that the Tour ran on a national team format; stage 20 was won by Jozef Huysmans (Belgium A), who finished 32nd overall when the race ended two days later.
In March 1968 staff were invited to watch the new documentary film about CERN. They probably enjoyed themselves, as Guido Franco’s aim was to inform the public through entertainment. He sought to engage an audience’s attention and make them want to learn, rather than forcing information on them. If that sounds uncontentious, you might be surprised at the strength of feeling the film aroused.
Despite considerable editing at the end of 1967 to meet criticisms of the first version, opinion still varied widely. Some were enthusiastic, feeling it captured the spirit and excitement of particle physics research; others found it frivolous, mocking scientists and portraying them as playboys having a wonderful time at the taxpayers’ expense. Even the fiercest critics thought it reflected great credit on Franco as a film-maker, however, they just feared it could do untold damage to the reputation of CERN.
In the 1960s, detection in particle physics mainly involved examining millions of photographs from bubble chambers or spark chambers. This was slow, labour-intensive and unsuitable for studies into rare phenomena.
Then came a revolution in transistor amplifiers. While a camera can detect a spark, a detector wire connected to an amplifier can detect a much smaller effect. In 1968, Georges Charpak developed the “multiwire proportional chamber”, a gas-filled box with a large number of parallel detector wires, each connected to individual amplifiers. Linked to a computer, it could achieve a counting rate a thousand times better than existing detectors. The invention revolutionized particle detection, which passed from the manual to the electronic era.
Charpak, who joined CERN in 1959, was awarded the 1992 Nobel prize in physics "for his invention and development of particle detectors, in particular the multiwire proportional chamber".
Today practically every experiment in particle physics uses some track detector based on the principle of the multiwire proportional chamber. Charpak has also actively contributed to the use of this technology in other fields that use ionizing radiation such as biology, radiology and nuclear medicine.
(image: ISOLDE experimental hall. The magnet of the ISOTOPE separator, the collection chamber and the control desk were placed in the same area as most of the experiments.)
The underground hall for ISOLDE is ready in 1967 and the first proton beam bombards the target on October 16. The first experiments are successful and prove that the online technique meets the expectations of the experimentalists. During the next year, a number of experiments produce short-lived isotopes of a several elements. The first paper is published early in 1969 and presents results for short-lived isotopes of the noble gases Ar, Kr, Xe and Rn and several other elements like Ag, Cd, I, Pt, Au, Hg, Po and Fr.
At its 81st meeting on 16 February 1967, CERN's Finance Committee authorized the purchase of the CDC 6400 computer, a small CDC 3100, and four magnetic tape units. The costs exceeded the funds available in the 1967 budget by 7-8 million Swiss francs. In its next meeting the Committee recommended the use of CERN's own funds for the purchase, "only raising a bank overdraft if this is necessary to cover the cash requirements".
The CDC 6400 was installed at CERN later that year.
The 3800 was a member of the 3000 series Control Data Corporation family of computers, incompatible with the 6000 series machines. The 3800 had a 48-bit architecture. Its 64 Kword core memory was replaced by a faster, 800-nanosecond memory during its stay at CERN. This machine was eventually acquired by the State of Geneva and installed at the local University of Geneva. At CERN it was replaced by a CDC 6400. It is worth noting that CERN acquired other machines of the 3000 series, such as a 3100 for the FOCUS project offering semi-interactive facilities and quick sampling of experimental data at the central computers, and a 3200 for interactive graphics applications.
(image: excavation work for ISOLDE underground hall in 1966)
On 8 May 1966, the CERN Synchrocyclotron begins a long shutdown until mid-July. During this time major modifications are carried out as part of a programme to improve the capacity of the machine and its associated facilities. One of the main items of work during the shutdown is the construction of a new tunnel for an external proton beam line to the new underground hall for the ISOLDE experiments. This tunnel is constructed underground to keep external radiation levels down and the existing proton room is kept for experiments that use beams of lower intensity.
On 21 February 1966 the Swiss Postal Authorities issued a 50 centime postage stamp in honour of CERN. Five Swiss artists visited CERN and were shown around the site, then each presented two designs. The judges selected a design by H. Kumpel showing the flags of the thirteen Member States of CERN superimposed on a bubble chamber photograph. The flags are arranged to represent the approximate outline of the Swiss border.
A further commemorative stamp was produced by France in 1977 for the inauguration of the Super Proton Synchrotron, and another Swiss stamp marked CERN’s 50th anniversary in 2004.
A suggestion to ease parking problems on the CERN site by allocating spaces didn’t go down well in 1965. Possibly the priority given to senior staff, and remarks about the benefits of an invigorating walk, gave offence. In any case, an alternative was proposed:
‘May I suggest instead that “senior administrators, division leaders" and the like, be provided with sedan-chairs or palanquins, in which they could be transported swiftly and effortlessly from corner to corner of the site. Other members of the staff would of course function as bearers. This would not only provide them with invigorating exercise, but also inculcate a due sense of their social position.’
A worried prospective bearer suggested motor scooters, as used by nuns on the wards of an Illinois hospital, instead. To prevent congestion indoors, use of the corridors could be limited to senior staff. Other people would get from office to office via the window ledges, not only enjoying healthful exercise but also freeing up more parking spaces as staffing levels gradually decreased when they fell off. The suggestion does not seem to have been adopted, but remains on file.
By 1965, all three particles that make up atoms (electrons, protons and neutrons) were known to each have an antiparticle. So if particles, bound together in atoms, are the basic units of matter, it is natural to think that antiparticles, bound together in antiatoms, are the basic units of antimatter.
But are matter and antimatter exactly equal and opposite, or symmetric, as Dirac had implied? The next important step was to test this symmetry. Physicists wanted to know how subatomic antiparticles behave when they come together. Would an antiproton and an antineutron stick together to form an antinucleus, just as protons and neutrons stick together to form the nucleus of an atom?
The answer to the antinuclei question was found in 1965 with the observation of the antideuteron, a nucleus of antimatter made out of an antiproton plus an antineutron (while a deuteron – the nucleus of the deuterium atom – is made of a proton plus a neutron). The goal was simultaneously achieved by two teams of physicists, one led by Antonino Zichichi using the Proton Synchrotron at CERN, and the other led by Leon Lederman, using the Alternating Gradient Synchrotron (AGS) accelerator at the Brookhaven National Laboratory, New York.
The CERN paper, Experimental Observation of Antideuteron Production was published in the Italian particle-physics journal Il nuovo cimento on 1 September 1965 (the journal ended when it was merged into the European Physical Journal in 1999.
The CDC 6600, made by the Control Data Corporation, arrived at CERN on 14 January 1965. It was the first multi-programmed machine in the CERN Computer Centre, with about 10 times the processing capacity of the IBM 7090.
The 6600 was used to analyse the 2-3 million photographs of bubble-chamber tracks that CERN experiments were producing every year. Human operators recorded significant observations from frames of bubble-chamber film onto punched cards. A machine called a Hough-Powell digitizer (HPD) scanned the cards and sent the information to the 6600. A device called YEP also measured significant tracks on bubble-chamber photographs, coded them onto paper tape, and sent this information to the computer. A third device – "Luciole" – provided the 6600 with fully automated measurements of spark-chamber film.
The CDC 6600 filled a large room. It consisted of 12 data channels, 10 peripheral processors, a central magentic-core memory and a central processor. Devices such as the HPD were connected directly to the computer by data channels. The 6600 was also connected to card readers that ran about 500 FORTRAN problems per day, and to two online computers – the SDS920 and the IBM 1800 – via CERN-made data links. The results of calculations on the 6600 were printed on paper or punched onto cards for further study.
The change-over from the IBM 7090 was planned to take 3 months starting in January 1965. Major engineering overhauls were needed during the first few years, which led to a 2-month shut-down in 1968 to modify the 6600: CERN's pre-production model needed to incorporate the logic and packaging improvements that had been introduced in CDC's production machines. During this period of struggling with hardware instability and software development, computing work at CERN was done partly by sending jobs to outside computers and partly by processing data on a CDC 3400, and later on a 3800, temporarily made available by the Control Data Corporation.
Find out more
- Video: The Control Data 6600 arrives at CERN
- For a more technical account, see "35 years ago – the Control Data 6600"
CDC 6600, serial number 3 (pre-production series machine)
On 10 April 1963, a number of European nuclear physicists meet at CERN to discuss the isotope separator project. A first outline is presented in an internal nuclear physics division report.
A Working Party is set up and a series of meetings are held from May to September. In a memorandum dated 26 October 1964 the chairman of the Nuclear Structure Committee Torleif Ericson recommends the on-line isotope separator project to CERN and on 9 November the Working Party submit a formal proposal.
On 17 December 1964 the Director-General gives formal permission to the groups behind the proposal to carry out the experiment.
The tradition of holding a Christmas party for CERN children began in the first year of CERN’s existence and still continues. In the early 1960s it was decided to hold two parties, so there would be room to invite non-CERN children from the neighbouring districts as well. In 1964 (on December 6 for those with names from A to K, and December 13 for the rest) children aged between four and twelve years old enjoyed a film, a conjurer and musical clowns, followed by refreshments. Transport was arranged for those requiring it, and parents were informed that although they would not be admitted to the party itself, arrangement had been made to keep the bar open for those wishing to remain during the festivities - Happy Christmas!
British physicist Peter Higgs, and independently Robert Brout and Francois Englert publish papers describing a mechanism which explains how particles could get mass. Higgs calls the hypothetical particle the "Higgs boson" in his paper Broken Symmetries and the Masses of Gauge Bosons, published on 19 October 1964 in the journal Physical Review Letters.
In 1964, James Cronin and Val Fitch at Brookhaven National Laboratory in the US did an experiment with particles called neutral K-mesons, or "kaons". The types of kaons they chose to study can be regarded to consist of one half ordinary matter and the other half antimatter. They started with two types of kaon that had seemingly identical masses but different lifetimes. Kaons of the long-lived type exist for 5.2 × 10-8 seconds before each decays into 3 pions. Kaons of the short-lived type exist for only 0.89 × 10-10 seconds before each decays into 2 pions.
Cronin and Fitch shot the two types of kaon down a 17-metre beamline and detected the resulting pion-decays at the other end.
Given the different lifetimes of the kaon types and the length of the beamline, you would expect only to see decays from the long-lived kaon type at the detector. Cronin and Fitch expected the short-lived kaon type to decay long before it reached the end of the beamline, and so its decay products would not be detected. In other words you would expect to detect only 3-pion decays and no 2-pion decays at all.
But in their experiment, Cronin and Fitch did detect 2-pion decays: 45 of them, out of a total of 22,700 decay events – a ratio of about 1 in 500. The result violated a fundamental principle of physics – the symmetry between matter and antimatter.
The pair announced their result in the paper "Evidence for the 2-pion Decay of the K Meson", published in the journal Physical Review Letters on 27 July 1964. They shared the 1980 Nobel prize in physics "for the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons."
If you were one of the estimated 70,000 visitors to CERN during the 2013 Open Days – or one of the 2,000+ volunteers busily organizing visits, games and all manner of weird and wonderful activities – you might not recognize this photo! Fifty years ago CERN’s Open Days were conducted on a much more modest scale.
Limited to families and guests of staff, CERN’s third Open Day on 25 April 1964 welcomed 1,100 visitors. Various CERN departments displayed their laboratories and equipment, and a kindergarten looked after the youngest visitors while their parents toured the site. A technical press day was also arranged on 19 May, with 36 visiting journalists. CERN’s Public Information Office reported good coverage of CERN’s activities during the year, despite “the general disinterest of the daily press in basic science”.
The IBM 7090 was installed at CERN in 1963. It was about four times more powerful than the 709. The computer was connected to a device call a Hough-Powell digitizer (HPD) – a machine that scanned films from bubble chambers, measured important tracks, and sent the information directly to the 7090. A second device, "Luciole", was also connected to the computer, providing fully automatic measurements from spark-bubble chambers. Over 300,000 frames of spark-chamber film were automatically scanned and measured in this way, beginning the trend towards online use of computers for processing experimental data.
Ran at CERN 1963 to 1965
Transistorized second-generation machine with a 2.18-microsecond clock cycle
Core storage: 32K words of 36 bits, 4.36-microsecond access time
Card 1/0, Tape units wrote on 7 tracks at 112.5 inches per second, 200 to 556 bytes per inch
8 data channels
Basic monitor operating system (IBSYS)
Connected online to flying-spot digitizers (HPD and Luciole) to measure bubble and spark chamber films
This remarkable photo, used on the cover of the May 1963 CERN Courier, captures the passage of protons extracted from CERN’s Proton Synchrotron (PS).
Initially, the PS had operated with internal targets, but when a beam of higher intensity was needed the fast ejection system was developed to eject the beam towards external targets. During the afternoon of Sunday 12 May 1963 the PS became the source of the world's first beam of 25 GeV protons to travel freely in air.
This photo was taken the following day by members of CERN’s Public Information Office. They placed blocks of plastic scintillator along the path of the beam and set up a camera to record the effect. As expected, the scintillators glowed brightly as the beam passed through them.
A buzz of excitement marked the start of neutrino experiments at CERN in 1963. As many years of hard work were about to be put to the test, this spoof advertisement appeared on the concrete shielding near the heavy liquid bubble chamber.
CERN inventions such as the fast ejection system, proposed in 1959 by Berend Kuiper and Günther Plass, and the magnetic horn, which earned Simon van der Meer his share of the Nobel prize for physics in 1984, had enabled CERN to produce the most intense beam of neutrinos in the world. The first run in June was anxiously awaited, but everything ran smoothly. During seven weeks a total of 4000 events were observed in the spark chamber and 360 in the bubble chamber, comparing very favourably with the 56 spark chamber events found in the previous neutrino experiment in Brookhaven.