NEWS
LHC: progress in commissioning proton beams. After becoming the world’s highest energy particle accelerator, the LHC is now making progress in commissioning stable beams and providing more collisions at the four points for several hours at a time. For the first time, beams have circulated with more than one bunch of protons, thus increasing the intensity.
On the evening of Tuesday, 8 December, two bunches per beam circulated for the first time at 1.18 TeV for a short period and ATLAS recorded its first collisions at the record energy of 2.36 TeV (centre of mass).
CERN – THE BULLETIN December 2009.LHC sets new world record. Geneva, 30 November 2009. CERN’s Large Hadron Collider has today become the world’s highest energy particle accelerator, having accelerated its twin beams of protons to an energy of 1.18 TeV in the early hours of the morning. This exceeds the previous world record of 0.98 TeV, which had been held by the US Fermi National Accelerator Laboratory’s Tevatron collider since 2001. It marks another important milestone on the road to first physics at the LHC in 2010. CERN PRESS RELEASE, November 2009. The LHC is back. Geneva, 20 November 2009. Particle beams are once again circulating in the world’s most powerful particle accelerator, CERN1’s Large Hadron Collider (LHC). This news comes after the machine was handed over for operation on Wednesday morning. A clockwise circulating beam was established at ten o'clock this evening. This is an important milestone on the road towards first physics at the LHC, expected in 2010. CERN PRESS RELEASE. November 20, 2009.
Half way round the LHC. Particles are smoothly making their way around the 27 km circumference of the LHC. Last weekend (7-8 November), the first bunches of injection energy protons completed their journey (anti-clockwise) through three octants of the LHC’s circumference and were dumped in a collimator just before entering the CMS cavern. Six of the eight sectors of the LHC have now been hardware commissioned to allow the passage of beams at 1.2 TeV. The remaining two (Sectors 3-4 and 8-1) will be powered up in the coming week. If all goes well, in just over one week from now, the beams could circulate in both pipes of the LHC. The first low-energy collisions should follow shortly after. CERN Bulletin November 2009.
…while the LHC gets colder and colder. The cool-down and commissioning of the LHC continues to progress well. Six of the eight sectors were at a nominal temperature of 1.9 K by the end of the first week of October, and the final two sectors, 3-4 and 6-7, were on course to be fully cold two weeks later. Teams are starting to power the magnets as each sector reaches 1.9 K, so the machine should be fully powered soon after the cool-down is completed. reparations are thus continuing towards the planned restart, with the injection of the first bunches of protons into the machine scheduled for mid-November. The procedure will be to establish stable beam initially in each direction, clockwise and anticlockwise, This will be followed by a short period of collisions at the injection energy of 450 GeV per beam. Commissioning will then begin on ramping the energy to 3.5 TeV, again working first with each beam in turn. After this, LHC physics will finally begin with collisions at this energy. CERN Courier. October 30, 2009. Towards the big chill. During the weekend of 25-29 September, particles (protons and ions) were injected into the transfer lines that link the SPS to the LHC. These crucial tests showed that the whole injection chain is ready.
Furthermore, six out of the eight LHC sectors are at operating temperature.
And the new Quench Detection System and the energy extraction system have both been tested and are performing well. CERN Bulletin, October 2009.Making more space for more people. The upcoming operation of the LHC is attracting and will continue to attract more and more researchers. To ensure that we are able to cope with this influx, our technical services have been busy increasing the office space available on the CERN site. On 9 September, an important milestone in this process was passed when we laid the foundation stone of Building 42, which will provide 300 additional workstations for scientists analysing the LHC data, in addition to the 800 already available in the adjoining Building 40. CERN BULLETIN September 2009. The Latest from the LHC: Switching on the magnets. The architecture of the LHC, which is partitioned into eight cryogenically and electrically independent sectors, allows the commissioning of the machine on a sector-by-sector basis. When a sector reaches nominal cryogenic conditions (-271.3 °C or 1.9 K), and provided that the control systems (Quench Detection System and Powering Interlock Controllers) work correctly and give the clearance, powering tests can be performed on the magnets. Currently, three sectors are at nominal cryogenic temperature and powering tests are being carried out in all three of them.
Current began to flow in the magnets of Sector 1-2 at the end of August. This week, the sector was the first to be powered with the new, recently installed Quench Detection System (QDS).
Magnet powering tests have also started in two other sectors, namely Sectors 5-6 and 7-8, where the new QDS is being installed. The two sectors are now ready for tests with higher current – the so-called Powering Phase II. CERN BULLETIN September 2009.LHC to run at 3.5 TeV for early part of 2009-2010 run rising later. Large Hadron Collider will initially run at an energy of 3.5 TeV per beam. The LHC will run at 3.5 TeV per beam, when it starts up in November this year, until a significant data sample has been collected and the operations team has gained experience in running the machine. Thereafter, with the benefit of that experience, the energy will be taken towards 5 TeV per beam. At the end of 2010, the LHC will be run with lead ions for the first time. After that, the LHC will shut down and work will begin on moving the machine towards 7 TeV per beam. CERN Press Release, August 2009. ALICE & LHCb: refinements for the restart. Following the previous issue, the Bulletin (CERN) continues its series to find out what the six LHC experiments have been up to since last September, and how they are preparing for the restart. Previously we looked at CMS and ATLAS; this issue we will round up the past 10 months of activity at ALICE and LHCb. CERN Bulletin. August 3rd 2009. Not a moment to lose at the LHC. But even with the accelerator shut down, there has been no time to relax. Physicists not involved in major repairs to the collider have been busy upgrading both equipment and software, making minor fixes that originally had been scheduled for the LHC's first winter shutdown, and repairing nagging problems that cropped up during years of construction. Symmetry, August 2009. LHCb have a new brochure. July 2009. Knocking on the door again. The LHC's anti-clockwise beam transfer system was tested on 6 and 7 June. Particle bunches were sent from the SPS through the 2.8 km transfer line towards the LHC where it intersects just before the LHCb cavern. The beam went down the transfer line and stopped just before reaching the LHC tunnel, where a beam stopper – 4 m of graphite – is physically placed in the beam line to prevent the beam from taking the last step into the LHC. Part of the LHCb detector was turned on during the beam test, allowing the reconstruction of tracks through the Vertex Locator. CERN Courier, July 2009. LHC Experiments: refinements for the restart. As the LHC restart draws closer, the Bulletin will be taking a look at how the six LHC experiments are preparing and what they have been up to since last September. In this issue we start with a roundup of the past 10 months of activity at CMS and ATLAS, both technical work and outreach activities. CERN Bulletin. July 20th 2009. All repairs in Sector 3-4 completed. All repairs in Sector 3-4, the sector damaged during the incident last September, have been completed and the sector has been closed up. After the last electrical interconnection was brazed, the final ‘W bellow’ - the large accordion-shaped sleeve that covers the interconnections between two magnets - was closed on 23 June. The teams have now started to pump the air out in order to leak-test the insulation vacuum. Once all the vacuum tests and electrical tests have been completed the sector will be ready to start the cool-down process. The Bulletin (CERN) June 2009. Final magnet for sector 3-4 goes underground. With all of the necessary magnets now underground, work in the tunnel will continue to connect them together. In total 53 magnets were removed from sector 3-4 following the incident on 19 September 2008. Of these, 16 magnets had sustained minimal damage and so were refurbished and put back into the tunnel; the remaining 37 were replaced by spares, depleting the number of reserve magnets to nearly zero. Work will continue on the surface to repair the remaining damaged magnets to replenish the pool of spares. CERN Courier. Jun 2009 First sector is closer to cool down. Installation of the new helium pressure-release system for the LHC is progressing well. The first sector to be fully completed is 5-6, with all 168 individual pressure-release ports now in place. These ports will allow a greater rate of helium escape in the event of a sudden increase in temperature. Cern Courier May 2009. ALICE prepares for jet measurements. The ALICE experiment has reached another milestone with the successful installation of the first two supermodules of the electromagnetic calorimeter (EMCal). ALICE is designed to study matter produced in high-energy nuclear collisions at the LHC, in particular using lead ions. The goal is to investigate thoroughly the characteristics of hot, dense matter as it is thought to have existed in the early universe. Cern Courier May 2009. LHC consolidation work proceeds apace. The new schedule foresees first beams in the LHC at the end of September 2009, with collisions in late October. A short technical stop has also been foreseen over the Christmas period. The LHC will then run through to the following autumn to ensure that the experiments have adequate data to carry out their first new-physics analyses and have results to announce in 2010. The new schedule also permits the possibility of lead-ion collisions in 2010. CERN Courier April, 2009. Fermilab Putting the Squeeze on Higgs Boson.
Scientists at the Department of Energy’s Fermi National Accelerator Laboratory have achieved the world’s most precise measurement of the mass of the W boson by a single experiment. Combined with other measurements, a tighter understanding of the W boson mass will also lead researchers closer to the mass of the elusive Higgs boson particle. The territory where the Higgs boson may be found continues to shrink. The latest analysis of data from the CDF and DZero collider experiments at the U.S. Department of Energy's Fermilab now excludes a significant fraction of the allowed Higgs mass range established by earlier measurements. Those experiments predict that the Higgs particle should have a mass between 114 and 185 GeV/c2. Now the CDF and DZero results carve out a section in the middle of this range and establish that it cannot have a mass in between 160 and 170 GeV/c2. Read more.
CERN launches new youth site on Web's 20th anniversary.
Geneva, 13 March 2009. Web veteran Robert Cailliau today launched CERNland, a new website for young people, on the occasion of the Web's 20th anniversary. CERNland has been developed to bring the excitement of CERN*'s research to a young audience aged 7 to 12 through a range of films, games and multimedia applications. It is available at http://www.cern.ch/cernland.Work continues apace on the repairs at the LHC. The crucial improvement since the incident in sector 3-4 is a new resistance-measurement system which can detect nano-ohm resistances in the joints. This new system would have prevented September’s incident and will prevent all imaginable failures of a superconducting joint in the future. For any "unimaginable" failure of a joint, the installation of new pressure-relief valves will reduce the amount of damage that occurs, compared with last year. CERN Courier March 2009 CERN management confirms new LHC restart schedule. CERN management confirmed the restart schedule for the Large Hadron Collider (LHC) resulting from the recommendations from 2 to 6 February 2009 Chamonix workshop. The new schedule foresees first beams in the LHC at the end of September this year, with collisions following in late October. A short technical stop has also been foreseen over the Christmas period. The LHC will then run through to autumn next year, ensuring that the experiments have adequate data to carry out their first new physics analyses and have results to announce in 2010. The new schedule also permits the possible collisions of lead ions in 2010. CERN February 2009. Mobilizing for the LHC. Investigations following the incident in Sector 3-4 of the LHC on 19 September have confirmed that the cause was a faulty electrical connection between two magnets. This resulted in mechanical damage and the release of helium from the magnet cold masses. CERN has published two reports on the incident and confirmed that the accelerator will be restarted in summer this year. CERN Courier January/February Volume 49 Issue 1. For the two reports, see more . Phenomenon of the Year. The Large Hadron Collider has been dubbed the "Phenomenon of the Year" by the editors of the prestigious journal Science. Science 19 December 2008. (LHC) will restart in the summer of 2009. CERN today confirmed today (December 8th ) that the Large Hadron Collider (LHC) will restart in the summer of 2009. A total of 53 magnet units have to be removed from the tunnel for cleaning or repair, of these, 28 have already been brought to the surface and the first two replacement units have been installed in the tunnel. The current schedule foresees the final magnet being reinstalled by the end of March 2009, with the LHC being cold and ready for powering tests by the end of June 2009. www.physorg.com December 2008. Breaking ground for Linac 4. Civil engineering work has started on Linac 4, a major new renovation project for the CERN accelerator complex. It will replace Linac 2 as the first link in the proton-injector chain after commissioning is completed, which is scheduled for 2013. CERN Courier. December 2008.
Large particle collider repairs to cost 16 million euro. Fixing the world's largest atom smasher will cost at least 25 million francs ($21 million) and may take until early summer, its operator said Monday. An electrical failure shut down the Large Hadron Collider on Sept. 19, nine days after the $10 billion machine started up with great fanfare.The Guardian, November 2008. CDF Ghost Muons. The CDF Collaboration, at Fermilab’s Tevatron accelerator, has submitted for publication a new paper describing a subsample of proton-antiproton collision events in which there is at least one muon produced far from the primary proton-antiproton interaction. This subsample is not yet described by known processes, including the effects of detector/reconstruction failures, and is starting to cause somewhat of a sensation in the high energy physics community. If these events were also produced in the forward direction, LHCb would be able to measure these quite well. Cosmic Variance. Novembre 2008. CERN releases analysis of LHC incident. Investigations at CERN1 following a large helium leak into sector 3-4 of the Large Hadron Collider (LHC) tunnel have confirmed that cause of the incident was a faulty electrical connection between two of the accelerator’s magnets. This resulted in mechanical damage and release of helium from the magnet cold mass into the tunnel. CERN Press Release. October 2008. The Nobel Prize in Physics 2008: Yoichiro Nambú (USA) / Makoto Kobayashi (Japan) and Toshihide Maskawa (Japan): "For the discovery of the mechanism of spontaneous broken symmetry in subatomic physics" and "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature". Nobel Prize.org, Octobre 2008. Update on the LHC. Preliminary investigations revealed that a problem in an electrical connection between two magnets caused a helium leak. Between one and two tonnes of liquid helium, of the 15 tonnes in the sector, spilled into the tunnel according to Lyn Evans, Project Leader of the LHC, when he spoke at the LHCC meeting on September 24th.
The investigative team believes that a faulty connection between two superconducting cables, called a bus bar splice, is to blame. These connections must be able to pass 12,000 amperes of current.
Dr Engelen is quick to point out that nothing can be known for certain until the magnets have been warmed to room temperature and opened for full inspection. While it hasn’t yet been confirmed, accelerator scientists have identified a likely scenario for the cause of the helium leak. The spliced region warmed so quickly that the superfluid helium system could not keep up with the cooling demand, causing the bus bar to melt or create an electric arc – either of which could have created a hole in the helium tube. ATLAS e-News. October 2008.
Let the number-crunching begin: the Worldwide LHC Computing Grid celebrates first data
Today (October 3rd) , three weeks after the first particle beams were injected into the Large Hadron Collider—the world’s largest particle accelerator—the Worldwide LHC Computing Grid celebrates the start of its crucial data challenge: the analysis and management of more than 15 million Gigabytes of data every year, to be produced from the hundreds of millions of subatomic collisions expected inside the LHC every second. This data-handling feat marks an essential stage in the process of enabling researchers to discover new physics. CERN Press Release. Geneve, October 2008.LHC re-start scheduled for 2009. . Investigations at CERN following a large helium leak into sector 3-4 of the Large Hadron Collider (LHC) tunnel have indicated that the most likely cause of the incident was a faulty electrical connection between two of the accelerator’s magnets.Geneva, 23 Sep 2008. CERN Press release. Incident in LHC sector 34. During commissioning (without beam) of the final LHC sector (sector 34) at high current for operation at 5 TeV, an incident occurred at mid-day on Friday 19 September resulting in a large helium leak into the tunnel.Geneva, 20 September 2008. CERN Website. First beam in the LHC - accelerating science. The first beam in the Large Hadron Collider at CERN was successfully steered around the full 27 kilometres of the world’s most powerful particle accelerator at 10h28 this morning. This historic event marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. Geneva, 10 September 2008. CERN PRESS RELEASE.
Fingers Crossed, Physicists Are Ready for Collider to Roll. At roughly 3:30 a.m. Eastern time, scientists at CERN, the European Organization for Nuclear Research, say they will try to send the first beam of protons around a 17-mile-long racetrack known as the Large Hadron Collider, 300 feet underneath the Swiss-French border outside Geneva. NEW YORK TIMES. September, 2008.
If the boson of Higgs did not exist, I would never understand anything any more. PETER HIGGS, British Physicist. Le Monde. September, 2008.
CERN fires up new atom smasher to near Big Bang. Europeans fire up new particle collider to see matter at birth of universe. NEWSWEEK, September, 2008.
Final LHC Synchronization Test a Success. CERN has today, 25 August 2008, announced the success of the second and final test of the Large Hadron Collider’s beam synchronization systems which will allow the LHC operations team to inject the first beam into the LHC. Friday evening 22 August, a single bunch of a few particles travelled down the transfer line from the Super Proton Synchrotron (SPS) accelerator to the LHC. (LHC First Beam. August, 2008).
LHC synchronization test successful. The synchronization of the LHC's clockwise beam transfer system and the rest of CERN's accelerator chain was successfully achieved last weekend. Tests began on Friday 8 August when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. (LHC First Beam. August 2008). CERN has today announced that the first attempt to circulate a beam in the Large Hadron Collider (LHC) will be made on 10 September. This news comes as the cool down phase of commissioning CERN’s new particle accelerator reaches a successful conclusion. Television coverage of the start-up will be made available through Eurovision.(CERN Press Release, August 2008). LHC collisions present no danger and that there are no reasons for concern. In the light of new experimental data and theoretical understanding, the LHC Safety Assessment Group (LSAG) has updated a review of the analysis made in 2003 by the LHC Safety Study Group, a group of independent scientists. LSAG reaffirms and extends the conclusions of the 2003 report that LHC collisions present no danger and that there are no reasons for concern. (CERN 2008. July 2008).
Recent measurements of the bizarre properties of B-mesons hint at the existence of new fundamental particles. Tim Gershon describes how the LHCb detector at CERN’s Large Hadron Collider could soon establish beyond doubt whether the effect is real. (Physicsworld.com June 2008).
Earth Will Survive After All, Physicists Say. That black hole that was going to eat the Earth? Forget about it, and keep making the mortgage payments — those of you who still have them. (New York Times June 2008).
Beam pipe installation. The very heart of any LHC experiment is not a pixel detector, nor or a vertex locator but a beam pipe. It is the site of each collision and the boundary where the machine and experiment meet. As an element of complex design and manufacture the CMS beam pipe was fifteen years in the making and finally fully installed on Tuesday 10th June. (CMS Times. June 2008).LHCb measures its first cosmic-ray muons. The LHCb team has for the first time measured cosmic rays passing through three of the experiment’s subdetectors simultaneously, selected by muon triggers. (CERN, Courier Jun 2008)
The Large Hadron Collider runs on woman power. Paola Catapano went in search of some of the women working on the LHC project, to find out about their work at CERN and talk about life in a mainly male environment. (CERN, Courier May 2008) Particle physics proves that arsenic didn't kill Napoleon. A meticulous new examination performed at the INFN laboratories in Milano-Bicocca and Pavia in Italy has shown that arsenic poisoning did not kill Napoleon. The researchers demonstrated that there is no evidence of a significant increase in the levels of arsenic in the emperor's hair during the final period of his life. (CERN, Courier May 2008) LHC hardware commissioning continues to make solid progress. Commissioning the LHC is making steady progress towards the target of achieving a complete cool down by the middle of June, allowing the first injection of beams soon after. This will come almost exactly 19 years after the start up of LEP, the machine that previously occupied the same tunnel. The LHC's first collisions will follow later. (CERN, Courier May 2008) Italian researchers claim they are first to have found dark matter. Researchers led by Dr Rita Bernabei at the University of Rome claim that a giant detector inside the mountain laboratory has picked up signs of dark matter. The signal suggests that it could be made of theoretical particles known as axions. The discovery was announced at a physics conference in Venice. The experiment was designed to detect dark matter in space as Earth flies through it. (The Guardian Thursday April 24 2008). Will new collider create black holes that destroy us all? Protons are actually pretty complicated objects, made of little bits and pieces, and in a collision of two protons it can happen that two of the little pieces find themselves very close together. Those pieces carry a lot of energy, and due to Einstein's equation one might imagine that a lot of mass in a little space could lead to a black hole. (Boston Globe April 21, 2008).
Cosmic tracks were recorded in the calorimeter system and the outer tracker of LHCb detector. Because LHCb is set up with the detectors aligned in vertical planes, it is not easy to record the tracks of cosmic rays. However, there are rare cosmic rays that travel almost horizontally at a rate of a fraction of a hertz through LHCb. (CERN, Courier Apr 2008). ALICE detector is already underway at CERN, and researchers are scrambling to add an electromagnetic calorimeter to capture jet-quenching, the newest way to look inside the quark-gluon plasma — the hot, dense state of matter that filled the earliest universe, which the Large Hadron Collider will soon recreate by slamming lead nuclei into one another. (Sciencie@Berkeley Lab, February 15, 2008). CERN recently celebrated the lowering of the 15th and last piece of the Compact Muon Solenoid (CMS) detector, an endcap of 1,430t, 100m underground on 10 March 2008. (HOIST , March 2008, Issue 69) New starter kit for CMS. It can take weeks to get into the groove of analyzing data from an unfamiliar detector. With a new starter kit, physicists at the Compact Muon Solenoid can cut that time to hours. (SYMMETRY, Vol 05, Januery/February 08) LHCb : un détecteur de toute beauté. Le but de LHCb est d’étudier la physique des particules contenant un quark b. LHCb prendra la suite d’expériences actuellement en fonctionnement au Japon (BELLE) et aux États-Unis (BABAR). (ELEMENTAIRE. Equinoxe d'été 2007). Asking a Judge to Save the World, and Maybe a Whole Lot More. Walter L. Wagner and Luis Sancho contend that scientists at CERN, have played down the chances that the collider could produce, among other horrors, a tiny black hole, which, they say, could eat the Eart. (The New York Times , March 29, 2008).
