Helium hole hiccup halts Hadron

Problem-prone particle project postponed

Leaks have been found in the vacuum of the Large Hadron Collider's insulating layer, causing yet another postponement of its restart from October to November.

The £2.7bn LHC machine - a particle accelerator in a 17 mile-long tunnel under the French and Swiss borders at Geneva - was set to restart in October, after a previous failure in its cooling systems caused serious damage when it was initially started up in September last year.

CERN (European Organisation for Nuclear Research) said that the damage was caused by a faulty splice in the high-current superconducting cable between two magnets in LHC sector 3-4. An internal CERN bulletin said that the latest delay has been caused by: "Vacuum leaks... found in two "cold" sectors of the LHC. The leaks were found in Sectors 8-1 and 2-3 while they were being prepared for... electrical tests... the leak is from the helium circuit to the insulating vacuum."

The bulletin says: "The repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector "floats" in temperature and the remainder of the sector is kept at 80 K (-316 degrees Fahrenheit) – a process that will require several weeks to complete)... the intervention will have an impact on the schedule for the restart. It is now foreseen that the LHC will be closed and ready for beam injection by mid-November."

Since the September shutdown, Austria has said it will withdraw from CERN involvement. The decision was later reversed. At the time, any suggestion that the UK might pull out was downplayed by CERN. Since then the scale of the black hole in UK government finances has emerged, as has the beginnings of a realisation that several years of public expenditure cuts may be needed to get finances back to normal. The government says it wants to preserve front line services, and the risk that UK funding of CERN may have to be scaled back is becoming greater. ®