LHC restart update
LHC run 2 is coming ever closer. Seven of the machine's eight sectors have successfully been commissioned to the 2015 operating energy of 6.5 TeV per beam, and the eighth is not far behind. There will, however, be no circulating beam in the LHC this week. An intermittent short circuit to ground in one of the machine's magnet circuits was identified on 21 March and is under investigation. It is a well understood issue, but one that could take time to resolve since it is in a cold section of the machine and repair may therefore require warming up and re-cooling after repair. "Any cryogenic machine is a time amplifier," said CERN's Director for Accelerators, Frédérick Bordry, "so what would have taken hours in a warm machine could end up taking us weeks."
Current indications suggest a delay of between a few days and several weeks. A full assessment is on going, and a revised schedule will be announced as soon as it is known. Whatever the case, the impact on LHC operation will be minimal: 2015 is a year for fully understanding the performance of the upgraded machine with a view to full-scale physics running in 2016-2018.
"All the signs are good for a great run 2," said CERN Director General Rolf Heuer. "In the grand scheme of things, a few weeks delay in humankind's quest to understand our universe is little more than the blink of an eye."
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, Israel, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a Candidate for Accession. Serbia is an Associate Member in the pre-stage to Membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Union, JINR and UNESCO have Observer Status.