December 18, 2012
CERN Announces Large Hadron Collider Will Now Sleep Until 2015
Lee Rannals for redOrbit.com — Your Universe Online
LHC completed its first three years of proton runs, and CERN said it will be giving the world's largest and most powerful particle accelerator a break.
The first three years of the LHC's proton-on-proton beam collision experiments have produced important finds, including the potential discovery of the Higgs boson, or "God particle."
CERN also said that the space between proton bunches in the beams was halved to further increase beam intensity during the three year run.
“This new achievement augurs well for the next LHC run starting in 2015,” CERN´s Director for Accelerators and Technology, Steve Myers, said in a statement. “High intensity beams are vital for the success of the LHC program. More intense beams mean more collisions and a better chance of observing rare phenomena.”
A beam in the LHC is not a continuous string of particles, but is divided into hundreds of proton bunches. Each of these bunches contains more than a hundred billion protons. CERN said that during the final days, the space between bunches had been successfully halved, achieving the design specification of 25 nanoseconds rather than the 50 nanoseconds.
Halving the bunch spacing allows the number of bunches in the beam to be doubled. A record number of 2,748 bunches was recorded in each beam last weekend, almost twice as many as the maximum reached in 2012.
CERN said several hours of physics were then performed with up to 396 bunches in each beam, spaced by 25 nanoseconds.
“The LHC´s performance has exceeded all expectations over the last three years,” Myers said. “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 has reached a value of more than twice the maximum value obtained in 2011, and the collision energy was increased by 7 TeV in 2011, to 8 TeV in 2012.
This improvement has allowed the LHC experiment to obtain important results quicker than expected.
CERN said 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. The organization said that LHC will resume activities in 2015 with an increased collision energy of 13 TeV, and another increase in luminosity.