View of a short-model magnet for the High Luminosity LHC quadrupole. (Image: Robert Hradil, Monika Majer/ProStudio22.ch)
While the Large Hadron Collider (LHC) is at the start of a new season of data taking, scientists and engineers around the world are already looking ahead, and working hard to develop its upgrade, the High-Luminosity LHC. This upgrade is planned to start operation in 2026, when it will increase the number of collisions by a factor of five to ten. Physicists will be able to take full advantage of this increased number of collisions to study the phenomena discovered at the LHC in greater detail.
This major upgrade to the machine requires installation of new equipment in 1.2 kilometres of the 27km-long-accelerator. Among the key components that will be installed are a set of new magnets: around 100 magnets of 11 new types are being developed.
More powerful superconducting quadrupole magnets will be installed at each side of the ATLAS and CMS detectors. Their purpose is to squeeze the particles closer, increasing the probability of collisions at the centre of the two experiments. These focusing magnets will exploit an innovative superconducting technology, based on the niobium-tin compound, which makes the quadrupoles’ magnetic field far greater, 50% higher than current LHC superconducting magnets based on niobium-titanium.
The magnets are now in the prototype phase – shorter models, on which tests are run to assess the stability of the design and the mechanical structure. Last year, two 1.5 metre-long short model quadrupoles were tested at CERN and at Fermilab, in the US. A third short model will soon be tested at CERN.
In January 2017, a full-length 4.5 metre-long coil – a world record-breaking length, for that kind of magnet – has been tested at the US Brookhaven National Laboratory and reached the nominal field value of 13.4 T. Meanwhile at CERN, winding the 7.15-metre-long coils for the final magnets has already begun.
The new magnets are being developed through a collaboration between CERN and the LHC-AUP (LHC Accelerator Upgrade Project) consortium, which involves three US laboratories.
This article is an excerpt from a feature article published here.
Watch the video!
(Video: Noemi Caraban Gonzalez/CERN)
This is an RF Cavity in the Recycler Ring in Fermilab’s Main Injector Tunnel, its most powerful particle accelerator (Image: Reidar Hahn/Fermilab)
Fifty years ago, physicists in the US established a new laboratory and with it a new approach to carrying out frontier research in high-energy physics. It began in the 1960's, when Cornell physicist Robert Rathbun Wilson saw early plans for a new accelerator in the US to rival Brookhaven National Laboratory in New York, and CERN in Switzerland, he considered them too conservative, unimaginative and too expensive. Wilson, being a modest yet proud man, thought he could design a better accelerator for less money and let his thoughts be known. By September 1965, he had proposed an alternative, innovative, less costly (approximately $90 million cheaper than the original) design. It was approved.
This period coincided with the Vietnam war, so the US Congress hoped to contain costs. Yet the discovery of the omega baryon particle at Brookhaven in 1964 meant high-energy physicists felt that a new high-energy accelerator was crucial to exploring new physics. Simultaneously, physicists were expressing frustration with the geographic situation of US high-energy physics facilities.
Groundbreaking in October 1969 for the new 200 GeV Synchrotron (Image: Fermilab)
Against this backdrop arose a major movement to accommodate physicists in the centre of the country and offer more equal access. Columbia University experimental physicist Leon Lederman championed “the truly national laboratory” that would allow any qualifying proposal to be conducted at a national, rather than a regional, facility. In 1965, a consortium of major US research universities, Universities Research Association (URA), Inc., was established to manage and operate the accelerator laboratory for the AEC (and its successor agencies the Energy Research and Development Administration (ERDA) and the Department of Energy (DOE)) and address the need for a more national laboratory.
Today, Wilson Hall, the central laboratory building, is the heart of the 6,800-acre Fermilab site. Following an architectural design competition among the DUSAF firms, it was built between 1971 and 1974. The design was acknowledged in 1975 with an award from the Society of American Registered Architects, and the building was named for Robert Rathbun Wilson on September 18, 1980. (Image: Reidar Hahn/ Fermilab)
Following a nationwide competition organised by the National Academy of Sciences, in December 1966 a 6800 acre site in Weston, Illinois, around 50 km west of Chicago, was selected. Another suburban Chicago site, north of Weston in affluent South Barrington, had withdrawn when local residents “feared that the influx of physicists would ‘disturb the moral fibre of their community’”. President Lyndon Johnson signed the bill authorising funding for the National Accelerator Laboratory on 21 November 1967.Science dedicated to human rights
“The formation of the Laboratory shall be a positive force…toward open housing…[and] make a real contribution toward providing employment opportunities for minority groups”
Robert Wilson, Director of Fermilab
Fermilab’s Betz Prairie was once the largest prairie reconstruction project on the planet. The site now hosts about 1,000 acres of restored prairie and is also home to a herd of bison, a symbol of Fermilab’s place on the frontier of physics. (Image: Fermilab)
It wasn’t easy to recruit scientific staff to the new laboratory in open cornfields and farmland with few cultural amenities. That picture lies in stark contrast to today, with the lab encircled by suburban sprawl encouraged by highway construction and development of a high-tech corridor with neighbours including Bell Labs/AT&T and Amoco. Wilson encouraged people to join him in his challenge, promising higher energy and more experimental capability than originally planned. He and his wife, Jane, imbued the new laboratory with enthusiasm and hospitality, just as they had experienced in the isolated setting of wartime-era Los Alamos while Wilson carried out his work on the Manhattan Project.
Wilson and colleagues worked on the social conscience of the laboratory and in March 1968, a time of racial unrest in the US, they released a policy statement on human rights.
They intended to: “seek the achievement of its scientific goals within a framework of equal employment opportunity and of a deep dedication to the fundamental tenets of human rights and dignity…The formation of the Laboratory shall be a positive force…toward open housing…[and] make a real contribution toward providing employment opportunities for minority groups…Special opportunity must be provided to the educationally deprived…to exploit their inherent potential to contribute to and to benefit from the development of our Laboratory. Prejudice has no place in the pursuit of knowledge…It is essential that the Laboratory provide an environment in which both its staff and its visitors can live and work with pride and dignity. In any conflict between technical expediency and human rights we shall stand firmly on the side of human rights. This stand is taken because of, rather than in spite of, a dedication to science.”
The campus brought inner-city youth out to the suburbs for employment, training them for many technical jobs. Congress supported this effort and was pleased to recognise it during the civil-rights movement of the late 1960s. Its affirmative spirit endures today.
Aerial view of Weston, the site for the National Accelerator laboratory in 1966 (Image: Fermilab)
Fermilab in 1977, showing the Main Ring accelerator (top) and Wilson Hall next to it. (Image: Fermilab)
By the 1970's experimentalists from Europe and Asia flocked to propose research at the new frontier facility in the US, forging larger collaborations with American colleagues. Its forefront position and philosophy attracted the top physicists of the world, with Russian physicists making news working on the first approved experiment at Fermilab in the height of the Cold War. Congress was pleased and the scientists were overjoyed with more experimental areas than originally planned and with higher energy, as the magnets were improved to attain higher and higher energies within two years. The higher energy in a fixed-target accelerator complex allowed more innovative experiments, in particular enabling the discovery of the bottom quark in 1977.
Fermilab has had many successes over the past fifty years, including the discovery of the bottom quark in 1977. (Image: Fermilab)
Superconducting-magnet technology was the future for high-energy physics, and was championed by Wilson, and a new director to take this forward was sought. Lederman, champion of the "national laboratory", spokesperson of the Fermilab study that discovered the bottom quark, and later a Nobel Prize winner for the discovery of the muon, accepted the position in late 1978 and immediately set out to win support for Wilson’s energy doubler - a colliding-beams accelerator, which would employ superconductivity. Experts from Brookhaven and CERN, as well as the former USSR, shared ideas with Fermilab physicists to bring superconducting-magnet technology to fruition at Fermilab. This led to a trailblazing era during which Fermilab’s accelerator complex, now called the Tevatron, would lead the world in high-energy physics experiments.
By 1985 the Tevatron had achieved 800 GeV in fixed-target experiments and 1.6 TeV in colliding-beam experiments, and by the time of its closure in 2011 it had reached 1.96 TeV in the centre of mass – just shy of its original goal of 2 TeV.
A Remote Operations Center in Wilson Hall and a special US Observer agreement allowed Fermilab physicists to co-operate with CERN on LHC research and participate in the CMS experiment. (Image: Maximilien Brice/CERN)
Lederman also expanded the laboratory’s mission to include science education, offering programmes to local high-school students and teachers, and in 1980 opened the first children’s centre for employees of any DOE facility. Lederman also reached out to many regions including Latin America and partnered with businesses to support the lab’s research and encourage technology transfer. The latter included Wilson’s early Fermilab initiative of neutron therapy for certain cancers, which later would see Fermilab build the 70–250 MeV proton synchrotron for the Loma Linda Medical Center in California.
A time-lapse of the Fermilab muon g-2 ring being installed and prepped, from June 27, 2014 to June 5, 2015. Replay Animation (Image: Fermilab)
In 1999, experimentalist and former Fermilab user Michael Witherell of the University of California at Santa Barbara became Fermilab’s fourth director. Mirroring the spirt of US–European competition of the 1960s, this period saw CERN begin construction of the Large Hadron Collider (LHC) to search for the Higgs boson. Accordingly, the luminosity of the Tevatron became a priority, as did discussions about a possible future international linear collider. After launching the Neutrinos at the Main Injector (NuMI) research programme, including sending the underground particle beam off-site to the MINOS detector in Minnesota, Witherell returned to Santa Barbara in 2005. Physicist Piermaria Oddone from Lawrence Berkeley Laboratory became Fermilab’s fifth director in 2005. He pursued the renewal of the Tevatron in order to exploit the intensity frontier and explore new physics with a plan called “Project X”, part of the “Proton Improvement Plan”. A Remote Operations Center in Wilson Hall and a special US Observer agreement allowed Fermilab physicists to co-operate with CERN on LHC research and participate in the CMS experiment. The Higgs boson was duly discovered at CERN in 2012 and Oddone retired the following year.
Under its sixth director, Nigel Lockyer, Fermilab now looks to shine once more through continued exploration of the intensity frontier and understanding the properties of neutrinos. In the next few years, Fermilab’s Long-Baseline Neutrino Facility (LBNF) will send neutrinos to the underground DUNE experiment 1300 km away in South Dakota, prototype detectors for which are currently being built at CERN. Meanwhile, Fermilab’s Short-Baseline Neutrino programme has just taken delivery of the 760 tonne cryostat for its ICARUS experiment after its recent refurbishment at CERN, while a major experiment called Muon g-2 is about to take its first results.
This suite of experiments, with co-operation with CERN and other international labs, puts Fermilab at the leading edge of the intensity frontier and continues Wilson’s dreams of exploration and discovery.
This article is a condensed excerpt from a feature article by Adrienne Kolb, published in The CERN Courier June 2017 issue, which you can read in full here.
One of the teams who won Beamline for Schools 2016 perform their experiment using a CERN accelerator beam (Image: Noemi Caraban Gonzalez/CERN)
CERN today announced the winners of its 2017 Beamline for Schools competition. “Charging Cavaliers” from Canada and “TCO-ASA” from Italy were selected from a total of 180 teams from 43 countries around the world, adding up to about 1500 high-school students. The winners have been selected to come to CERN in September to carry out their own experiments using a CERN accelerator beam.
With the Beamline for Schools competition, high-school students are enabled to run an experiment on a fully-equipped CERN beamline, in the same way that researchers do at the Large Hadron Collider and other CERN facilities. Students had to submit a written proposal and video explaining why they wanted to come to CERN, what they hoped to take away from the experience and initial thoughts of how they would use the particle beam for their experiment. Taking into consideration creativity, motivation, feasibility and scientific method, CERN experts evaluated the proposals. A final selection was presented to the CERN scientific committee responsible for assigning beam time to experiments, who chose two winning teams to carry out their experiments together at CERN.
“The quality and creativity of the proposals is inspiring. It shows the remarkable talent and commitment of the new generation of potential scientists and engineers. I congratulate all who have taken part this year; they can all be proud of their achievements. We very much look forward to welcoming the two winning teams and seeing the outcome of their experiments” CERN Director for International Relations, Charlotte Warakaulle
“Charging Cavaliers” are thirteen students (6 boys and 7 girls) from the “École secondaire catholique Père-René-de-Galinée” in Cambridge, Canada. Their project is the search for elementary particles with a fractional charge, by observing their light emission in the same type of liquid scintillator as that used in the SNO+ experiment at SNOLAB. With this proposal, they are questioning the Standard Model of particle physics and trying to get a glimpse at a yet unexplored territory.
“I still can’t believe what happened. I feel incredibly privileged to be given this opportunity. It’s a once a lifetime opportunity It opens so many doors to a knowledge otherwise inaccessible to me. It represents the hard work our team has done. There’s just no words to describe it. Of course, I’m looking forward to putting our theory into practice in the hope of discovering fractionally charged particles, but most of all to expanding my knowledge of physics.” said Denisa Logojan from the Charging Cavaliers.
Watch the Charging Cavaliers's proposal video here (Video: Charging Cavaliers/Beamline for Schools/CERN)
“TCO-ASA” is a team from the “Liceo Scientifico Statale "T.C. Onesti"” in Fermo, Italy, and comprises 8 students (6 boys and 2 girls). They have taken the initiative to build a Cherenkov detector at their school. This detector has the potential of observing the effects of elementary particles moving faster than light does in the surrounding medium. Their plan is to test this detector, which is entirely made from low-cost and easily available materials, in the beam line at CERN.
“I'm really excited about our win, because I've never had an experience like this. Fermo is a small city and I've never had the opportunity to be in a physics laboratory with scientists that study every day to discover something new. I think that this experience will bring me a bit closer to my choices for my future” said Roberta Barbieri from TCO-ASA team.
The eight students from Italy sent their video proposal for their project, A blue light in the darkness (Video: TCo-ASA/Beamline for Schools/CERN)
The first Beamline for Schools competition was launched three years ago on the occasion of CERN’s 60th anniversary. To date, winners from the Netherlands, Greece, Italy, South Africa Poland and the United Kingdom have performed their experiments at CERN. This year, short-listed teams2 each receive a Cosmic-Pi detector for their school that will allow them to detect cosmic-ray particles coming from outer space.
“After four editions, the Beamline for Schools competition has well established itself as an important outreach and education activity of CERN. This competition has the power to inspire thousands of young and curious minds to think about the role of science and technology in our society. Many of the proposals that we have received this year would have merited an invitation to CERN.”, said Markus Joos, Beamline for School project leader.
Beamline for Schools is an education and outreach project supported by the CERN & Society Foundation, funded by individuals, foundations and companies. The project was funded in 2017 in part by the Arconic Foundation; additional contributions were received by the Motorola Solutions Foundation, as well as from National Instruments. CERN would like to thank all the supporters for their generous contributions that have made the 2017 competition possible.
ICARUS has been at CERN for refurbishment before it makes its way to Fermilab over the next few months (Image: Maximilien Brice/CERN)
It’s lived in two different countries and is about to make its way to a third. It’s the largest machine of its kind, designed to find extremely elusive particles and tell us more about them. Its pioneering technology is the blueprint for some of the most advanced science experiments in the world. And this summer, it will travel across the Atlantic Ocean to its new home (and its new mission) at the U.S. Department of Energy’s Fermi National Accelerator Laboratory.
We'll be hosting a Facebook live today to tell you more about the ICARUS story, sign up to watch it live on Facebook.
The ICARUS detector measures 18 meters (60 feet) long and weighs 120 tons. It began its scientific life under a mountain at the Italian National Institute for Nuclear Physics’ (INFN) Gran Sasso National Laboratory in Italy in 2010, recording data from a beam of particles called neutrinos sent by CERN [LINK]. The detector was shipped to CERN in 2014, where it has been upgraded and refurbished in preparation for its overseas trek.
“We are very pleased and proud that CERN has been able to contribute to the refurbishment of the ICARUS detector and we are looking forward to first results from the Fermilab short-baseline neutrino programme in the coming years,” said Fabiola Gianotti, Director-General of CERN.
When it arrives at Fermilab, the massive machine will take its place as part of a suite of three detectors dedicated to searching for a new type of neutrino beyond the three that have been found. Discovering this so-called “sterile” neutrino, should it exist, would rewrite scientists’ picture of the universe and the particles that make it up.
“Nailing down the question of whether sterile neutrinos exist or not is an important scientific goal, and ICARUS will help us achieve that,” said Fermilab Director Nigel Lockyer. “But it’s also a significant step in Fermilab’s plan to host a truly international neutrino facility, with the help of our partners around the world.”
First, however, the detector has to get there. Next week it will begin its journey from CERN in Geneva, Switzerland to a port in Antwerp, Belgium. From there the detector, separated into two identical pieces, will travel on a ship to Burns Harbor, Indiana, in the United States, and from there will be driven by truck to Fermilab, one piece at a time. The full trip is expected to take roughly six weeks.
The detector uses liquid-argon time projection technology – essentially a method of taking a 3-D snapshot of the particles produced when a neutrino interacts with an argon atom – which was developed by the ICARUS collaboration, and now is the technology of choice for the international Deep Underground Neutrino Experiment (DUNE), prototypes of which are currently being built at CERN.
"More than 25 years ago Nobel Prize winner, and a previous CERN Director-General, Carlo Rubbia started a visionary effort with the help and resources of INFN to make use of liquid argon as a particle detector, with the visual power of a bubble chamber but with the speed and efficiency of an electronic detector,” said Fernando Ferroni, president of INFN. “A long series of steps demonstrated the power of this technology that has been chosen for the gigantic future experiment DUNE in the U.S., scaling up the 760 tons of argon for ICARUS to 70,000 tons for DUNE. In the meantime, ICARUS will be at the core of an experiment at Fermilab looking for the possible existence of a new type of neutrino. Long life to ICARUS!”
This research is supported by the DOE Office of Science, CERN and INFN, in partnership with institutions around the world.
International Archives Day, 9 June, is an opportunity to discover treasures from our shared heritage. The CERN archives contain some 1000 metres of shelves filled with letters, notes and reports. CERN also preserves a large number of films, photos, videos and objects. These precious nuggets contain 63 years of CERN’s history and are a chapter in the unique story that is scientific adventure.
CERN also owns the scientific archive of 1945 Nobel prize-winning physicist, Wolfgang Pauli. This small, but historically valuable, collection was donated by Pauli’s widow who, with the help of friends, tracked down originals or copies of his letters. His correspondence, with Bohr, Heisenberg, Einstein and others, provides an invaluable resource and insight into the development of 20th century science.
Read more about CERN archives here.
This image shows a simulation of the electron clouds development when the proton beam passes through the vacuum chamber. (Image: CERN)
Protons are jostling for space in the Large Hadron Collider. Since the start of the physics run on 23 May, the operators of the huge accelerator have been increasing the intensity of the beams, injecting more and more protons in order to increase the number of collisions.
“Trains” of proton bunches have been circulating in the machine for the past week. Consisting of up to 288 bunches, each containing more than 100 billion protons, the trains are formed by the accelerator chain and then sent into the large ring. They are then accelerated to a speed close to that of light for around twenty minutes, before they collide with each other in the centre of each experiment. Recently, 600 bunches have been circulating in each direction. The aim is to reach 2500 bunches in each beam within a few weeks.
To achieve this, the machine specialists must first improve the surface conditions of the vacuum chambers in which the protons circulate. Obtaining the best possible vacuum is an essential prerequisite to make an accelerator work. Molecules remaining in the vacuum chamber are obstacles to the circulation of the protons – it is like sending Formula 1 cars around a track full of parked cars. Hence, before starting up the accelerator, the vacuum specialists pump the air out of the beam pipes, obtaining a high-quality vacuum, almost as good as on the surface of the moon (10-10 or even 10-11 millibar). This is enough to allow the circulation of a few hundred proton bunches, but beyond that, things get harder.
Despite the ultra-high vacuum, residual gas molecules and electrons remain trapped on the walls of the vacuum chambers. When the beam circulates, these electrons are liberated from the surface of the walls due to the impact of lost particles or photons emitted by the LHC proton beams. They are accelerated by the beam’s electrical field and hit the walls on the opposite side of the chamber, detaching trapped molecules and freeing more electrons. If the number of liberated electrons is larger than the number of impacting electrons, it may initiate an avalanche of electrons, which will destabilise the beam. This phenomenon, known as the “electron cloud”, is amplified by the large number of proton bunches and the short distance between the bunches in the beam.
To mitigate the impact of these clouds, the vacuum chamber can be conditioned with the beam itself. Increasing the number of circulating bunches frees as many molecules of gas as can be sustained and causes a massive release of electron clouds. Experience has shown that, once this operation, called "scrubbing", has been carried out, the production rate of gas molecules and electrons progressively falls. This allows the beam intensity to be increased stepwise until the LHC can be filled completely.
So it’s time for spring cleaning at the LHC. For five days, starting today, the LHC operators will carry out scrubbing of the vacuum chambers with beam. The physics run will take a short break, starting again in much better conditions mid-June.
The first students participating in the High-School Students Internship Programme (HSSIP) during their visit to SM18 (Image: Julien Marius Ordan/CERN)
At CERN, you can see student interns all year round, but this year you may also spot the first participants of the official High-School Students Internship Programme (HSSIP). HSSIP is a programme developed by the ECO group’s Teacher and Student Programmes section to engage students from a young age with scientific research and innovation.
The HSSIP was launched in May 2017 with the arrival of a group of 22 Hungarian students, aged between 16 and 19. They were offered an intense two-week internship at CERN, during which they took part in many diverse activities. Accompanied by mentors of the same nationality, the students got a deeper insight into particle physics by working on their own projects, through a variety of visits, and through a cloud chamber workshop at CERN’s S’Cool Lab. The students also participated as a team in the CERN Relay Race – the annual running competition held on CERN’s campus – and finished second.
The students were selected by a national committee headed by Dezsö Horváth – Professor Emeritus at Wigner Research Centre for Physics in Budapest. High-school physics teachers were asked to propose their best students to take part in the programme. “More than 50 applications were received and the selection of the final students was a challenging task. We paid special attention to diversity and finally we selected students from 21 different high schools in Hungary,” says Peter Jurcso, who is responsible for the Hungarian Programme at CERN.
“Participating in the programme had many benefits for me. I learned a little bit of programming and how to work efficiently in a team. The people here are great – I can talk to anybody and I can ask anything. I definitely want to come back here one day as engineer,” said Daniel Nagy, one of the students who took part.
“It is wonderful to get out of the classroom where everything is in theory and to see how things are happening in the real world. It is amazing for me to see how every physicist programmes, and how managing big data requires such types of knowledge as well,” commented Balazs Mehes, also part of the group.
The Hungarians had the opportunity to discover science, technology, engineering, and mathematics in the CERN context and environment, to strengthen their understanding of science and to develop their skills in a high-tech environment. “We are delighted that the HSSIP is now officially included among our various educational offerings,” commented Sascha Schmeling, head of the Teacher and Student Programmes section at CERN.
Hungary is one of the five pilot states – Bulgaria, France, Hungary, Norway and Portugal – that will participate in the programme. Hopefully, in coming years, the programme will be made available to all CERN Member States. The internship is held in one of the national languages of the Member State concerned.
More information about the upcoming programmes can be found here.
CERN also runs highly successful educational programmes for teachers and students. In 2016 a milestone was reached when the 10,000th teacher came to CERN as part of the International High School Teacher (HST) programme.
An image of a proton–proton collision taken in the LHCb detector on 23 May. (Image: LHCb/CERN)
Physics at the LHC has kicked off for another season. Today, the Large Hadron Collider shifted up a gear, allowing the experiments to start taking data for the first time in 2017. Operations are starting gradually, with just a few proton bunches per beam. The operators who control the most powerful collider in the world will gradually increase the number of bunches circulating and will also reduce the size of the beams at the interaction points. In a few weeks’ time, over a billion collisions will be produced every second at the heart of the experiments.
Last year, the LHC produced an impressive amount of data, no fewer than 6.5 million billion collisions, representing an integrated luminosity over the course of the year of almost 40 inverse femtobarns. Luminosity, which corresponds to the number of potential collisions per surface unit in a given time period, is a crucial indicator of an accelerator’s performance. In 2017, the operators are hoping to produce the same number of collisions as in 2016, but over a shorter period, since the LHC has started up a month later due to the extended year-end technical stop.
“Over the first two years of operation at a collision energy of 13 TeV, we built up an excellent understanding of how the LHC works, which will allow us to optimise its operation even further in the third year,” says Frédérick Bordry, Director for Accelerators and Technology at CERN. “Our goal is to increase the peak luminosity even further and to maintain the LHC’s excellent availability, which in itself would be a great achievement.”
An image of a proton–proton collision taken in the CMS detector on 23 May. (Image: CMS/CERN)
Particle physics relies on the statistical analysis of various phenomena, so the size of the samples is crucial. In other words, the greater the number of collisions that reveal a certain phenomenon, the more reliable the result is. The experiments intend to take advantage of the large quantity of data supplied by the LHC to continue their exploration of physics at the highest energy ever obtained by an accelerator.
“The LHC experiments are well prepared to double their statistics compared to what they obtained in 2016 at 13 TeV. Thanks to the new data, they will be able to reduce the uncertainties that surround their observations every time we enter unchartered territory,” says Eckhard Elsen, Director for Research and Computing.
The LHC physicists are working on two different broad areas: improving their knowledge of known phenomena and probing the unknown. The known phenomena constitute the Standard Model of Particles and Forces, a theory that encompasses all our current knowledge of elementary particles. The Higgs boson, discovered in 2012, plays a key role in the Standard Model. It is also a scalar particle, fundamentally different to the other elementary particles. In 2017, ATLAS and CMS will continue to work on determining the characteristics of this particle. These two large general-purpose experiments will observe its decay modes and how it interacts with other particles. Their measurements may provide indications of possible new physics beyond the Standard Model. The experiments will also carry out precise measurements of other processes of the Standard Model, in particular those involving the top quark, the elementary particle with the greatest mass.
Physicists hope to be able to identify disparities between their measurements and the Standard Model. This is one of the ways in which the unknown can be probed. Although it describes a lot of the phenomena of the infinitely small precisely, the Standard Model leaves many questions unanswered. For example, it describes only 5% of the universe; the rest is formed of dark matter and dark energy, the nature of which are as yet unknown.
Every discrepancy with regard to the theory could direct physicists towards a larger theoretical framework of new physics that might resolve the enigmas we face.
One of the early collision events with stable beams recorded by ATLAS on 23 May 2017, with a reconstructed muon candidate. The upper panes show transverse views of the detector and the muon spectrometer, while the lower panes show ATLAS in longitudinal cross-section and a view of the energy deposits in the cells of the ATLAS calorimeters. (Image: ATLAS/CERN)
ATLAS, CMS and LHCb measure processes precisely to detect anomalies. ATLAS and CMS are also looking for new particles, such as those predicted by the theory of supersymmetry, which could be the components of dark matter.
LHCb is also interested in the imbalance between matter and antimatter. Both of these would have been created in equal quantities at the time of the Big Bang, but antimatter is now practically absent from the universe. LHCb is tracking the phenomenon known as “charge-parity violation” which is thought to be at least partly responsible for this imbalance.
No lead ion collisions, which are the ALICE experiment’s specialist subject, are planned at the LHC this year. ALICE will continue its analysis of the 2016 data and will record proton-proton collisions, which will also allow it to study the strong force. On the basis of the proton-proton collisions from 2016, ALICE recently announced that it had observed a state of matter resembling quark-gluon plasma. Quark-gluon plasma is the state of matter that existed a few millionths of a second after the Big Bang.
Finally, several days of physics running with de-squeezed beams are planned for the TOTEM and ATLAS/ALFA experiments.
To find out more about physics at the LHC, you can watch our Facebook Live event tomorrow Wednesday 24 May at 4 pm CEST.
Astronaut Peggy Whitson during the 200th spacewalk from the International Space Station (Image credit: NASA)
The 200th spacewalk at the International Space Station (ISS) included a new installation on the Alpha Magnetic Spectrometer (AMS) – a particle-physics detector that was assembled at CERN.
On 12 May, Commander Peggy Whitson and Flight Engineer Jack Fischer of NASA conducted the four-hour spacewalk, while ESA astronaut Thomas Pesquet stayed inside the ISS to drive the station arm that positions the two astronauts.
One of their tasks involved replacing a cable with a bus terminator – a type of connector – to carry data between AMS and the space shuttle. During the spacewalk, the AMS team stationed at CERN in the experiment’s Payload and Operations Control Centre (POCC), were able to check that the bus terminator was properly functioning. This connection will be used from 2018, when a new thermal cooling system for the AMS silicon tracker is put into place.
The AMS cooling pump system was developed by the collaboration at CERN, and a similar system is now also used by some of the LHC experiments to cool their trackers. Despite only needing one pump, AMS was flown to space with four. Now, three of the four pumps are no longer functioning and so multiple spacewalks are planned for 2018 to replace these with a new cooling system, which would extend the life of AMS in space by 12 years.
AMS was launched in 2011 on the penultimate flight of the Space Shuttle and has been collecting data during the last six years. It is a particle-physics detector looking for dark matter, antimatter and missing matter and also performs precision measurements of cosmic rays. It reached the milestone of recording 100 billion cosmic ray events on 8 May.
His Majesty King Abdullah II following the opening of SESAME, flanked by Heads of the delegations of the SESAME Members and Directors of International Organisations that have supported SESAME**. (Image: Noemi Caraban Gonzalez/CERN)
Allan, Jordan, 16 May 2017. The SESAME light source was today officially opened by His Majesty King Abdullah II. An intergovernmental organization, SESAME is the first regional laboratory for the Middle East and neighbouring regions The laboratory’s official opening ushers in a new era of research covering fields ranging from medicine and biology, through materials science, physics and chemistry to healthcare, the environment, agriculture and archaeology.
Speaking at the opening ceremony, the President of the SESAME Council, Professor Sir Chris Llewellyn Smith said: “Today sees the fulfilment of many hopes and dreams. The hope that a group of initially inexperienced young people could build SESAME and make it work - they have: three weeks ago SESAME reached its full design energy. The hope that, nurtured by SESAME’s training programme, large numbers of scientists in the region would become interested in using SESAME – they have: 55 proposals to use the first two beamlines have already been submitted. And the hope that the diverse Members could work together harmoniously. As well as being a day for celebration, the opening is an occasion to look forward to the science that SESAME will produce, using photons provided by what will soon be the world’s first accelerator powered solely by renewable energy.”
SESAME, which stands for Synchrotron-light for Experimental Science and Applications in the Middle East, is a particle accelerator-based facility that uses electromagnetic radiation emitted by circulating electron beams to study a range of properties of matter. Its initial research programme is about to get underway: three beamlines will be operational this year, and a fourth in 2019. Among the subjects likely to be studied in early experiments are pollution in the Jordan River valley with a view to improving public health in the area, as well as studies aimed at identifying new drugs for cancer therapy, and cultural heritage studies ranging from bioarcheology – the study of our ancestors – to investigations of ancient manuscripts. Professor Khaled Toukan the Director of SESAME, said “In building SESAME we had to overcome major financial, technological and political challenges, but – with the help and encouragement of many supporters in Jordan and around the world – the staff, the Directors and the Council did a superb job. Today we are at the end of the beginning. Many challenges lie ahead – including building up the user community, and constructing additional beamlines and supporting facilities. However, I am confident that - with the help of all of you here today, including especially Rolf Heuer, who will take over from Chris Llewellyn Smith as President of the Council tomorrow (and like Chris and his predecessor Herwig Schopper is a former Director General of CERN) - these challenges will be met.”
The opening ceremony was an occasion for representatives of SESAME’s Members and Observers to come together to celebrate the establishment of a competitive regional facility, building regional capacity in science and technology.
**To the KIng’s left, HRH Princess Sumaya of Jordan, who headed the Jordanian delegation, and Fabiola Gianotti, Director General of CERN; to the right, Irena Bokova, Director Generla of UNESCO, and Carlos Moedas, European research commissioner.
One of the first proton-proton collisions seen by the ALICE experiment in 2017, on May 13, during the LHC beam commissioning phase. ALICE used these first collisions to fine-tune its equipment and get ready for the new physics season of LHC. (Image: CERN)
Last week, the detectors of the Large Hadron Collider (LHC) witnessed their first collisions of 2017. These test collisions were not for physics research, instead they were produced as part of the process of restarting the LHC. But have patience, data taking for physics will start in another few days.
Since particles began circulating in the large ring once more, the LHC’s operators have been testing and adjusting 24 hours a day to turn the LHC into a veritable collision factory. Their work involves forming trains of bunches, building them up over the next few weeks to several hundred and then several thousand bunches per beam.
To establish this production line of particles, all of the accelerator’s systems must be perfectly adjusted. The LHC is an extremely complex machine comprising thousands of subsystems and it takes weeks to adjust them all.
This image shows a beam splash, as observed by the ATLAS experiment on 29 April, the day of the LHC restart. The beam splashes are generated by aiming beams at the collimators near to the experiments, in this case 140 metres from the ATLAS interaction point. Once the LHC is back in operation, the experiments use the beam splashes to synchronise their sub-detectors with the accelerator’s clock. (Image: CERN)
The first particles circulated on 29 April 2017 and, soon after, the operators started work on their long list of adjustments. They tested the radiofrequency system, which accelerates the particles. They brought the beam energy up to its operating value of 6.5 TeV. They tested the beam dump system, which ejects the particles into a block of graphite if required. They tested and aligned all the collimators – jaw-like devices that close around the beam to absorb stray particles. They carried out proton bunch ramp and squeeze cycles. Finally, they performed fine adjustments of the hundreds of corrector magnets, adjusting the trajectory of the beam to a precision of one micron at the collision points.
Last Wednesday, they started to collide the beams to be able to adjust the interaction points at the heart of the experiments. This step is carried out with so-called “pilot” beams, containing fewer than ten bunches and fewer protons than during the physics runs. These first collisions also allow the experiments to adjust their detectors.
In the coming days, the operators will continue to adjust and align the equipment. Once all of these steps are complete, they will be able to announce “stable beams”, the long-awaited signal for the start of the new data-taking season for the experiments.
A beam splash, as observed by the CMS experiment on 29 April. In contrast to proton-proton collisions where the particles come from the center of the detector, in splash events particles traverse the detector horizontally, from one side to the other. (Image: CERN)
On Friday 12 May at 4:30pm CEST, we will be live from the CERN Data Centre with three European astronauts:
- Helen Sharman - the first Brit in space, and first woman to visit the MIR orbital complex (Soviet space station).
- Samantha Cristoforetti holds the record for the longest continuous time in space for an ESA astronaut and female astronauts in general.
- Claude Nicollier - first ESA astronaut selection, with 4 space missions on the Space Shuttle, one of them devoted to repair the Hubble Space Telescope. He was also the first European to undertake a spacewalk
CERN is not just the home of the Large Hadron Collider - it hosts a variety of experiments, control centres and services related to space. The Alpha Magnetic Spectrometer (AMS-02) is a particle physics detector that looks for dark matter, antimatter and missing matter from a module attached to the outside of the International Space Station (ISS). It was assembled at CERN and physicists receive and analyse the data sent by AMS at the AMS Payload Operations Control Centre (POCC) at CERN. Also UNOSAT, which has been hosted by CERN’s IT department since its inception in 2001, relies on the Laboratory’s IT infrastructure to produce extremely precise maps of regions of the world affected or threatened by natural disaster or conflict, based on very high resolution satellite images.
Join us live in the CERN Data Centre, where the astronauts will be answering your questions, so post them in the comments section of the live.
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A new piece of free, online software, called SHINE3D, has been developed by researchers at CERN’s NA61/SHINE experiment to show the physics data they’re creating in 3D.
The software allows anybody to visualise exactly the tracks particles leave as they fly through the detector inside the experiment, and will help to explain the physics as well as provide scientists with a new way of analysing the data.
“We wanted it to be accessible and understandable for everyone, so even a child could see how interesting it is. This is a very important task for all of the experiments at CERN - to bring science closer to people,” explains Filip Michalski who created the website with his colleague Taras Palayda at the University of Wrocław.
While the 3D visualisations can be explored on any web browser, the software also allows anyone with virtual reality goggles to get even closer to the raw data.
Try the website for yourself here:
(Image: Maximillien Brice/ CERN)
World class champion for drone freestyle driving and racing, Chad Nowak, came to CERN to record acrobatic footage. Watch this acrobatic video to get a glimpse of the CERN data centre: the heart of CERN’s entire scientific, administrative, and computing infrastructure.
Racing drone tours CERN data centre (Video: Chad Nowak/ CERN)
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At a ceremony today, CERN inaugurated its linear accelerator, Linac 4, the newest accelerator acquisition since the Large Hadron Collider (LHC) (Image: Maximilien Brice/ CERN)
At a ceremony today, CERN inaugurated its linear accelerator, Linac 4, the newest accelerator acquisition since the Large Hadron Collider (LHC). Linac 4 is due to feed the CERN accelerator complex with particle beams of higher energy, which will allow the LHC to reach higher luminosity by 2021. After an extensive testing period, Linac 4 will be connected to CERN’s accelerator complex during the upcoming long technical shut down in 2019-20. Linac 4 will replace Linac 2, which has been in service since 1978. It will become the first step in CERN’s accelerator chain, delivering proton beams to a wide range of experiments.
“We are delighted to celebrate this remarkable accomplishment. Linac 4 is a modern injector and the first key element of our ambitious upgrade programme, leading up to the High-Luminosity LHC. This high-luminosity phase will considerably increase the potential of the LHC experiments for discovering new physics and measuring the properties of the Higgs particle in more detail,” said CERN Director General, Fabiola Gianotti.
“This is an achievement not only for CERN, but also for the partners from many countries who contributed to designing and building this new machine,” said CERN Director for Accelerators and Technology, Frédérick Bordry. “Today, we also celebrate and thank the wide international collaboration that led this project, demonstrating once again what can be accomplished by bringing together the efforts of many nations.”
The linear accelerator is the first essential element of an accelerator chain. In the linear accelerator, the particles are produced and receive the initial acceleration; the density and intensity of the particle beams are also shaped in the linac. Linac 4 is an almost 90-metre-long machine sitting 12 metres below the ground. It took nearly 10 years to build.
Linac 4 will send negative hydrogen ions, consisting of a hydrogen atom with two electrons, to CERN’s Proton Synchrotron Booster (PSB), which further accelerates the negative ions and removes the electrons. Linac 4 will bring the beam up to 160 MeV energy, more than three times the energy of its predecessor. The increase in energy, together with the use of hydrogen ions, will enable double the beam intensity to be delivered to the LHC, thus contributing to an increase in the luminosity of the LHC.
Luminosity is a parameter indicating the number of particles colliding within a defined amount of time. The peak luminosity of the LHC is planned to be increased by a factor of five by 2025. This will make it possible for the experiments to accumulate about 10 times more data over the period 2025 to 2035 than before. The High-Luminosity LHC will therefore provide more accurate measurements of fundamental particles than today, as well as the possibility of observing rare processes that occur beyond the machine’s present sensitivity level.
CAST, CERN's axion solar telescope, moves on its rail to follow the Sun (Image: Max Brice/CERN)
In a paper published today in Nature Physics, the CAST experiment at CERN presented new results on the properties of axions – hypothetical particles that would interact very weakly with ordinary matter and therefore could explain the mysterious dark matter that appears to make up most of the matter in the universe.
Axions were postulated by theorists decades ago, initially to solve an important issue in the Standard Model of particle physics related to the differences between matter and antimatter. The particle was named after a brand of washing detergent, since its existence would allow the theory to be “cleaned up”.
A variety of Earth- and space-based observatories are searching possible locations where axions could be produced, ranging from the inner Earth to the galactic centre and right back to the Big Bang.
The CERN Axion Solar Telescope (CAST) experiment is looking for axions from the sun using a special telescope called a helioscope constructed from a test magnet originally built for the Large Hadron Collider. The 10-metre-long superconducting magnet acts like a viewing tube and is pointed directly at the sun: any solar axions entering the tube would be converted by its strong magnetic field into X-ray photons, which would be detected at either end of the magnet by specialised detectors. Since 2003, the CAST helioscope, mounted on a movable platform, has tracked the movement of the sun for an hour and a half at dawn and an hour and a half at dusk, over several months each year. The detector is aligned with the sun with a precision of about one hundredth of a degree.
In the paper published today, based on data recorded between 2012 and 2015, CAST finds no evidence for solar axions. This has allowed the collaboration to set the best limits to date on the strength of the coupling between axions and photons for all possible axion masses to which CAST is sensitive. “The limits concern a part of the axion parameter space that is still favoured by current theoretical predictions and is very difficult to explore experimentally,” explains the deputy spokesperson for CAST, Igor Garcia Irastorza. “For the first time, we have been able to set limits that are similar to the more restrictive constraints set by astrophysical observations,” he says.
Since 2015, CAST has broadened its research at the low-energy frontier to include searches for other weakly-interacting particles from the dark energy sector, such as “solar chameleons”. The experience gained by CAST over the past 15 years will also help physicists define the detection technologies suitable for a proposed, much larger, next-generation axion helioscope called IAXO.
“Even though we have not been able to observe the ubiquitous axion yet, CAST has surpassed even the sensitivity originally expected, thanks to CERN’s support and unrelenting work by CASTers,” says CAST spokesperson Konstantin Zioutas. “CAST’s results are still a point of reference in our field.”
More information on the results can be found in the scientific paper.
Timelapse video of CAST following the Sun in the morning and in the evening (Video: Madalin-Mihai Rosu/CERN)
Final tests were performed in the LHC at the end of April, ready for the restart this weekend (Image: Maximilien Brice/ CERN)
Today, the LHC once again began circulating beams of protons, for the first time this year. This follows a 17-week-long extended technical stop.
Over the past month, after the completion of the maintenance work that began in December 2016, each of the machines in the accelerator chain have, in turn, been switched on and checked until this weekend when the LHC, the final machine in the chain, could be restarted by the Operations team.
“It’s like an orchestra, everything has to be timed and working very nicely together. Once each of the parts is working properly, that’s when the beam goes in, in phases from one machine to the next all the way up to the LHC,” explains Rende Steerenberg, who leads the operations group responsible for the whole accelerator complex, including the LHC.
Each year, the machines shut down over the winter break to enable technicians and engineers to perform essential repairs and upgrades, but this year the stop was scheduled to run longer, allowing more complex work to take place. This year included the replacement of a superconducting magnet in the LHC, the installation of a new beam dump in the Super Proton Synchrotron and a massive cable removal campaign.
Among other things, these upgrades will allow the collider to reach a higher integrated luminosity – the higher the luminosity, the more data the experiments can gather to allow them to observe rare processes.
“Our aim for 2017 is to reach an integrated luminosity of 45 fb-1 [they reached 40 fb-1 last year] and preferably go beyond. The big challenge is that, while you can increase luminosity in different ways – you can put more bunches in the machine, you can increase the intensity per bunch and you can also increase the density of the beam – the main factor is actually the amount of time you stay in stable beams,” explains Steerenberg.
In 2016, the machine was able to run with stable beams – beams from which the researchers can collect data – for around 49 per cent of the time, compared to just 35 per cent the previous year. The challenge the team faces this year is to maintain this or (preferably) increase it further.
The team will also be using the 2017 run to test new optics settings – which provide the potential for even higher luminosity and more collisions.
“We’re changing how we squeeze the beam to its small size in the experiments, initially to the same value as last year, but with the possibility to go to even smaller sizes later, which means we can push the limits of the machine further. With the new SPS beam dump and the improvements to the LHC injector kickers, we can inject more particles per bunch and more bunches, hence more collisions,” he concludes.
For the first few weeks only, a few bunches of particles will be circulating in the LHC to debug and validate the machine. Bunches will gradually increase over the coming weeks until there are enough particles in the machine to begin collisions and to start collecting physics data.
Learn more about the restart:
Rende Steerenberg is in charge of the Operations teams, who today are back in the CERN Control Centre as the LHC is turned on with beam for the first time in 2017 (Image: Sophia Bennett/CERN)
Rende Steerenberg is affectionately known around CERN as the man who pushes the button to restart the LHC, but he is emphatic that this isn’t the case.
“It’s not just my job, and it’s not just one button,” he grins, after hearing the accolade. Rende’s real job title is leader of the Operations group – a team that make sure the LHC and the accelerator chain, together with the technical infrastructure, are running smoothly.
Today, the Large Hadron Collider restarted after almost five months of maintenance and upgrades. And the reason Rende (rightly) claims it’s not just one button, is because starting up the LHC requires a slow process of switching on each individual part of the accelerator chain in turn, until it gets to the final, biggest machine.
“I did a lot of Alpinism before the kids were born. It’s quite dangerous so I stopped once they were around, but we still go hiking with them in the mountains a lot,” says Rende Steerenberg, who runs the Operations group at CERN. “Like in my private life, in our daily work we have to take responsibility for our actions.” (Image: Sophia Bennett/CERN)
“To get things done here you have to run the accelerator but you can’t work alone. There are many people working day and night to run the accelerators. And you have to be in contact with the Proton Synchroton operator, who has to be in contact with the SPS or the Booster operator, and if something is not right they all have to work together.”
Giving credit where it’s due is crucial to Rende’s role as a manager, and something he enjoys so much he believes that even if he hadn’t ended up in a science role, he’d have been in management somehow, working in a team.
“As the Group Leader I have to manage the group and the resources and make sure everything can work, that people have the right tools, hiring, etc. It all takes a lot of my time. But I’m still very closely involved in the running of the machines, discussions about increasing the performance of the injectors, producing brighter beams, increasing the LHC’s integrated luminosity, it’s all still part of my job, which is fortunate as that’s a very interesting part of it too.” – Rende Steerenberg speaking about managing the teams who meet in the CCC shown above (Image: Sophia Bennett/CERN)
The operations teams work in shifts at CERN’s Control Centre (the CCC), where each corner of the room is an island of computer screens devoted to a specific machine. It’s in the CCC that the social, team-building nature of Rende’s group becomes clear.
“My favourite bit of my working day is coming into the CCC in the morning. I scan through the logbooks over breakfast but then I come in and listen to the people who run the machines about how the night went. What were the issues, and the successes?” shares Rende.
“It’s a hugely well-functioning dynamic, people bring pasta to night shifts!” – Rende Steerenberg
For him, it’s made even more enjoyable when it’s a point of shift turnover, when different people are passing through the CCC. Working in shifts, seeing people bring in shared pasta dishes to sustain them through long nights, is what Rende, among other things, thinks gives the team such a well-functioning dynamic.
“It’s a different life in a control room to working in an office. If we had an argument, you might hide in your office, me in mine and one of us would call and say, ‘Can we discuss it again over coffee?’ But that might take days. In the control room that can’t happen, you have to meet up the next night when no-one else is around, you have to sit next to each other and you have to work out issues in the same island. It’s a special atmosphere, more family like.”
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The European Organization for Nuclear Research (CERN1) and the American Physical Society (APS2) signed an agreement today for SCOAP3(link is external) – the Sponsoring Consortium for Open Access Publishing in Particle Physics. Under this agreement, high-energy physics articles published in three leading journals of the APS will be open access as from January 2018.
All authors worldwide will be able to publish their high-energy physics articles in Physical Review C, Physical Review D and Physical Review Letters at no direct cost. This will allow free and unrestricted exchange of scientific information within the global scientific community and beyond, for the advancement of science.
“Open access reflects values and goals that have been enshrined in CERN’s Convention for more than sixty years, such as the widest dissemination of scientific results. We are very pleased that the APS is joining SCOAP3 and we look forward to welcoming more partners for the long-term success of this initiative”, said Fabiola Gianotti, CERN’s Director General.
APS CEO Kate Kirby commented that, “APS has long supported the principles of open access to the benefit of the scientific enterprise. As a non-profit society publisher and the largest international publisher of high-energy physics content, APS has chosen to participate in the SCOAP3 initiative in support of this community.”
With this new agreement between CERN and the APS, SCOAP3 will cover about 90 percent of the journal literature in the field of high-energy physics.
Convened and managed by CERN, SCOAP3 is the largest scale global open access initiative ever built. It involves a global consortium of 3,000 libraries and research institutes from 44 countries, with the additional support of eight research funding agencies. Since its launch in 2014, it has made 15 000 articles by about 20 000 scientists from 100 countries accessible to anyone.
The initiative is possible through funds made available from the redirection of former subscription money. Publishers reduce subscription prices for journals participating in the initiative, and those savings are pooled by SCOAP3 partners to pay for the open access costs, for the wider benefit of the community.