The LHC’s quench: stop for 2 months

News from the CERN of Geneva. On the 20th September at 11:27 am (Local Time) another accident in the cooling-plant of the LHC will stop the experiments for at least two months. Last Wednesday a break-down in an electric transformer caused a short pause of the works, but on Thursday it has been replaced and made functional. Then yesterday a leak of helium, always in the cooling-plant, caused by the bad functioning of the connection between two magnets, raised the temperatures from -271C to -268C, which has switched the security system on.

Scientists assure: “No danger for people”

Italian Umberto Dosselli, Vice-president of the National Institute of Nuclear Physics says that the fault is “quite easy to repair, but it needs a very long time”. That’s because, to accomplish it, the temperatures must be raised and then lowered again, and this can’t be done in a short time. At the moment of the accident the used energy was of 5 teV (teraelettronvolt, that is to say 10^12 elettronvolt), a little more than a third of the one which is going to be used in 2009 to realize the most important experiments. So low temperature (less than outer space) are very near to the absolute zero (0 Kelvin), and they make the superconductivity of the magnets possible. The loss of this property, caused when the temperatures raised up, has delayed the first protons collisions, which should have been done on next week.

Fortunately there hasn’t been any wounded among the staff, as it is forbidden to enter the sectors when the system is in function.

The fear of the people for the possible risks of the LHC, even if the physics keep on saying that there are not, are increased by the facts of the last week, which the scientists had not foreseen. Today the bosses of the CERN have given a meeting to analyze the situation.