The Large Hadron Collider particle accelerator at Cern, just outside Geneva, has been immobilised temporarily after a short circuit - caused by a weasel.
“The Large Hadron Collider (LHC) is on standby mode, following technical issues in the last 24 hours, including a power cut due to the passage of a weasel on a 66 kV/18kV electrical transformer,” European Organization for Nuclear Research (Cern) spokesman Arnaud Marsollier told swissinfo.ch on Friday.
He said the affected part of the LHC stopped immediately and safely, though some connections were slightly damaged due to an electrical arc.
The incident took place in the early hours of Friday morning. The weasel did not survive the encounter.
Marsollier said it may take a few days to repair the damage, but that such events had happened a few times in the past and were part of the life of such a large installation.
“Operators and technicians are at work to resume the LHC operation commissioning and start the 2016 physics campaign at the LHC,” he said in an email.
In 2009 the LHC had a small short circuit caused by what was suspected to be bread dropped by a bird.
The Cern daily summary for Friday April 29 concludes: "Not the best week for LHC!"