Sunday, 2 March 2008


I'm spending this week in La Thuile - a ski resort in the Italian Alps. This is where the electroweak session of Rencontres de Moriond takes place. In Moriond, the ethical dilemma Tommaso once wrote about is most accute. The conference venue is just 50 meters from the ski lift and theres is a discount on skipass for the participants. This year, however, the snow conditions are pretty bad, so I'm actually attending to some of the talks.

The useful thing about going 100 kilometers south and one kilometer up from Geneva is that I could learn something about the LHC. Lyn Evans, who is the alpha and the omega of the LHC project, gave a talk this morning about the construction progress. He showed the new cooldown schedule which looks like this

It seems that the delay is not as bad as some of us feared. Sector 45 will be the last to be completed because it needs to be warmed up for the installation of the inner triplet magnet. Still, it is expected to be cold again in the middle of June. This is the earliest when beam commissioning may start. The current plan is to get first collisions by the end of August. This, of course, depends on a number of unpredictable factors, yet it is reassuring that so far no major problems have arisen. Another interesting thing Lyn said is that the preferred option at the moment is to run the machine at 5-6 TeV (10-12 TeV in the center of mass frame, instead of 14 TeV) in the first year.

The new schedule should soon appear on the LHC homepage. The link to Lyn's talk is here.


Peter Woit said...

I'm very confused about this. This schedule just shows the cooldown. Previous schedules show, after cooldown, for each sector, a 2-3 month period for powering tests before beam commissioning begins. These have only now been done for one sector (4-5). According to this document

"the earliest that the machine could be ready for beam commissioning to 7 TeV is late August".

I gather that running the machine at 5 rather than 7 TeV allows them to bypass some of what was planned for the period of powering tests, but does this really mean that if they only go to 5 TeV they can start beam commissioning in late June rather than late August??

Jester said...

I'm not very familiar with all the technical details involved. All I can say is that Lyn pointed to August as the realistic date of first collisions. I'm not competent to say anything beyond that.