Latest LHC News

July 2011

The Large Hadron Collider has exceeded the anticipated performance for 2011. At the end of June the number of LHC experimental collisions exceeded 100 million million, which had been the objective set for the whole of 2011. This performance bodes well for further advances over the coming months. At present, the spacing between the bunches in the LHC is 50 ns, with some bigger gaps here and there to allow the injection and extraction kickers to do their job. The maximum number of bunches that we can inject in the machine with a 50 ns spacing is 1380, and this has been achieved setting world records for the number of collisions/second. A nominal LHC bunch contains around 1.15x10¹¹ protons. The 1380 nominal bunches now in use gives a total of 1.6x10¹⁴ protons per beam and a combined energy of around 89 MJ at 3.5 TeV/beam.

Results are being presented at a major meeting in Grenoble and include a wide range of searches for new physics and precise measurements of Standard Model processes. Major extensions to our knowledge have already been achieved.

Geneva, November 8th, 2010

First operation of the LHC with lead ions accelerated to the full energy of 287 TeV per beam. This energy is much higher than for proton beams because lead ions contain 82 protons. The three experiments recording data with lead ions, ALICE, ATLAS and CMS can now look forward to continuous lead-ion running until CERN's winter technical stop begins on 6 December.

Lead-ion running opens up an entirely new avenue of exploration for the LHC programme, probing matter as it would have been in the first instants of the Universe's existence. One of the main objectives for lead-ion running is to produce tiny quantities of such matter, which is known as quark-gluon plasma, and to study its evolution into the kind of matter that makes up the Universe today. This exploration will shed further light on the properties of the strong interaction, which binds the particles called quarks, into bigger objects, such as protons and neutrons.

Following the winter technical stop, operation of the collider will start again with protons in February, and physics runs will continue through 2011.

Geneva, November 4th, 2010

The LHC began a month long operation to collide lead ions to study the physics of the early Universe a billionth of a second after the Big Bang.

Geneva, November 1st, 2010

The LHC completed its 2010 data taking with proton proton collisions at 7 TeV. The accelerator and detectors performed flawlessly setting world records for accelerators and opening up a new energy regime for exploration. There was not sufficient data for new discoveries, but previously discovered high mass particles were visible as well as intriguing hints of new phenomena to be explored in 2011.

Geneva, August 20th, 2010

Over the past two weeks the LHC operations team has pushed into new territory in terms of stored beam power. Moving to 25 bunches per beam at the end of July meant operation with a stored energy in each beam of more than 1 MJ (One million joules). This corresponds to the current record for stored beam energy in existing hadron accelerators (e.g. CERN’s SPS and Fermilab’s Tevatron) and it marks an energy regime where a sudden loss of beam or operational errors can result in serious damage to equipment: an energy of 1 MJ is sufficient to melt 2 kg of copper. . This effort has resulted in record results for the LHC performance in terms of delivered luminosity. For the first time the peak luminosity surpassed 4x1030 cm-2 s-1 and the total integrated luminosity delivered to the experiments passed the milestone of 1 inverse picobarn (1 pb-1 or 1000 nb-1) over the weekend 7-8 August.

The number of bunches in each beam was increased from 25 to 49 on Thursday 19 August. This will be followed by a change to operation with bunch trains in September. Operating the machine with bunch trains will open the door for increasing the total number of bunches in successive steps, so improving the LHC’s luminosity over the coming months by another factor of 10 to 100.

Geneva, March 30th, 2010

On March 30th 2010 the LHC achieved collisions with counter rotating proton beams of 3.5 TeV for a total energy of 7 TeV. This energy is 3.5 times larger than the collisions at Fermilab, the worlds previous highest energy accelerator. The LHC has opened a new energy frontier where major discoveries are expected.

The LHC is expected to run at this energy until the end of 2011. In 2012 upgrades will be made so that in 2013 the energy can be increased to 13 TeV.

Geneva, November 2009

First beam circulated in the Large Hadron Collider on 20 November 2009, and first collisions at 900 GeV (450 GeV per beam) followed on 23 November. The LHC set a world record for beam energy on 29 November, accelerating beams to energies of 1.18 TeV. These are important milestones on the road towards first physics at the LHC, which will begin with collisions at 7 TeV (3.5 TeV per beam). The first high energy collisions will most likely occur in the first quarter of 2010.

This is the start of a fantastic era of physics and discoveries after 20 years' work by the international community to build a machine and detectors of unprecedented complexity and performance

You can follow the progress of the LHC and interact with the physicists by using twitter and YouTube.http://www.twitter.com/cern

http://www.youtube.com/cern In addition the Quantum diaries web site allows you to follow physicists as they chronicle their lives in real time.

http://www.quantumdiaries.org

15 May, 2009

On May 15, 2009, Sony Pictures Entertainment released Angels & Demons, starring Tom Hanks. The film focuses on an apparent plot to destroy the Vatican using antimatter stolen from the European particle physics laboratory CERN.

Through a series of public lectures, scientists are using this opportunity to tell the world about the real science of antimatter, the Large Hadron Collider and the excitement of particle physics research. CERN has invited Tom Hanks to return late in 2009 and throw the switch to restart the LHC.

Public Lectures

Angels & Demons - The Science Revealed

Geneva, 30 April 2009

The 53rd and final replacement magnet for CERN’s Large Hadron Collider (LHC) was lowered into the accelerator’s tunnel today, marking the end of repair work above ground following the incident in September last year that brought LHC operations to a halt. Underground, the magnets are being interconnected, and new systems installed to prevent similar incidents happening again. The LHC is scheduled to restart in the autumn, and to run continuously until sufficient data have been accumulated for the LHC experiments to announce their first results.The final magnet, a quadrupole designed to focus the beam, was lowered this afternoon and has started its journey to Sector 3-4, scene of the September incident. With all the magnets now underground, work in the tunnel will focus on connecting the magnets together and installing new safety systems, while on the surface, teams will shift their attention to replenishing the LHC's supply of spare magnets.

In total 53 magnets were removed from Sector 3-4. Sixteen that sustained minimal damage were refurbished and put back into the tunnel. The remaining 37 were replaced by spares and will themselves be refurbished to provide spares for the future.CERN is publishing regular updates on the LHC in its internal Bulletin, available at http://www.cern.ch/bulletin , as well as via twitter and

YouTube at http://www.twitter.com/cern and http://www.youtube.com/cern

Geneva, 5 December 2008

LHC to restart in 2009CERN has conducted a detailed analysis of the problem that occurred and has now issued a new schedule for LHC operation. It is expected that beams will be circulated and collisions occur in late summer 2009. You can read the press release and see some images of the damage at http://press.web.cern.ch/press/PressReleases/Releases2008/PR17.08E.html

Geneva, 16 October 2008.

Analysis of the Large Hadron Collider Incident

On the 19th of September an electrical connection failed as current was being increased in the magnets that guide the proton beams. There is now a detailed analysis of the cause of the failurehttp://press.web.cern.ch/press/PressReleases/Releases2008/PR14.08E.htmlAs yet there is no definite time table for the LHC to circulate beam but the earliest date would be May 2009.

Geneva, Tuesday September 23rd, 2008

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. Before a full understanding of the incident can be established the sector has to be brought to room temperature and the magnets involved opened up for inspection. This will take three to four weeks. Full details of this investigation will be made available once it is complete.

"Coming immediately after the very successful start of LHC operation on 10 September, this is undoubtedly a psychological blow," said CERN Director General Robert Aymar."Nevertheless, the success of the LHC’s first operation with beam is testimony to years of painstaking preparation and the skill of the teams involved in building and running CERN’s accelerator complex. I have no doubt that we will overcome this setback with same degree of rigor and application."The time necessary for the investigation and repairs precludes a restart before CERN’sobligatory winter maintenance period, bringing the date for restart of the accelerator complex to early spring 2009. LHC beams will then follow.Particle accelerators such as the LHC are unique machines, built at the cutting edge of technology. Each is its own prototype, and teething troubles at the start-up phase are always possible.

Explanation
Handling and storing liquid Helium and the complicated procedures necessary for warm up and cool down set the time for warm up to a few weeks and a total time of two months providing any repair is straightforward. The total complex at CERN involves many accelerators and a number of other experiments and a shutdown from early December until March was always part of the schedule and cannot be changed.

Monday September 22nd, 2008

At the following link you can find a special issue of the CMS time which is a special edition to commemorate the first circulation of beam in the LHC and its first trip through the CMS detector. http://cmsinfo.cern.ch/outreach/CMSTimes.html

Friday September 19th, 2008

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. Preliminary investigations indicate that the most likely cause of the problem was a faulty electrical connection between two magnets which probably melted at high current leading to mechanical failure. CERN's strict safety regulations ensured that at no time was there any risk to people. A full investigation is underway, but it is already clear that the sector will have to be warmed up for repairs to take place. This implies a minimum of two months down time for the LHC operation. For the same fault, not uncommon in a normally conducting machine, the repair time would be a matter of days.

Explanation
The magnets in the LHC produce a force on the circulating protons which provides the centripetal force to keep the protons moving in a circular path of radius ~ 2.7 miles. Protons are injected into the LHC at low energy and then accelerated. As the energy (and speed) increases the magnet field has to increase to keep the protons at a fixed radius and therefore the current in the coils of the magnets has to be increased. During the test of high current operation a component failed. As in the case of any normal conductor heat is produced as a current flows (e.g. a toaster) in the failure this heat caused a connection to melt.