The First LHC Protons Run Ends with New Milestone

“This new achievement augurs well for the next LHC run starting in 2015,” said CERN’s Director for Accelerators and Technology, Steve Myers, “High intensity beams are vital for the success of the LHC programme. More intense beams mean more collisions and a better chance of observing rare phenomena.”

To put this into context, of the 6 million billion proton-proton collisions generated by the LHC, the ATLAS and CMS experiments have each recorded around 5 billion collisions of interest over the last three years. Of these, only around 400 produced results compatible with the Higgs-like particle whose discovery was announced in July.

A beam in the LHC is not a continuous string of particles, but is divided into hundreds of bunches, each a few tens of centimetres long. Each bunch contains more than a hundred billion protons. During the last few days, the space between bunches has been successfully halved, achieving the design specification of 25 nanoseconds rather than the 50 nanoseconds used so far. Halving the bunch spacing allows the number of bunches in the beam to be doubled. A record number of 2748 bunches was recorded in each beam last weekend, almost twice as many as the maximum reached previously in 2012, but at the injection energy of 450 GeV and without collisions. Several hours of physics were then performed with up to 396 bunches in each beam, spaced by 25 nanoseconds, each beam being accelerated to the energy of 4 TeV.

“The LHC’s performance has exceeded all expectations over the last three years,” said Steve Myers, “The accelerator delivered more than 6 million billion collisions and the luminosity has continuously increased. It’s a fantastic achievement, and I’m incredibly proud of my team.”

The luminosity, a crucial parameter measuring the rate of collisions of an accelerator, has reached a value of 7.7x1033cm-2s-1, more than twice the maximum value obtained in 2011 (3.5x1033cm-2s-1). The collision energy was increased from 7 TeV in 2011 to 8 TeV in 2012.

This year-on-year improvement in performance has allowed the LHC experiments to obtain important results quicker than expected. In addition to the spectacular discovery of a Higgs-like particle announced in July, the experiments have led to many other studies improving our understanding of fundamental matter.

At the beginning of 2013, the LHC will collide protons with lead ions before going into a long maintenance stop until the end of 2014. Running will resume in 2015 with increased collision energy of 13 TeV and another increase in luminosity.

1. CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its member states are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. Cyprus, Israel and Serbia are associate members in the pre-stage to membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have observer status.

Media Contact

Press office Newswise

More Information:

http://www.cern.ch

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors