LHC portal

Here is the latest on the Hump from Evian
http://indico.cern.ch/getFile.py/access ... fId=107310

The UPS is now the prime suspect.

Interesting and optimistic Reuters report on prospects for next year

http://feeds.reuters.com/~r/reuters/sci ... QU20101115

The reason for going back to proton physics is that the source of lead ions ran dry. It will take a couple of days to fill it so in the meantime they can do a bit more proton MD. They will return to ion physics on Friday but I guess they might run again and get another three days for protons.

Z means the atomic number which is 82 for lead, so the energy per ion is 3.5 x 82 TeV

It now says the energy is 3.5 Z TeV. Z is the atomic number which is 82 so the energy per beam is 3.5x82 = 287 TeV. Since there are 208 nucleons in the ion, the energy per nucleon is 287/208 = 1.38 TeV and the centre of mass energy per nucleon is 3x1.38 = 2.76 TeV. That was the number they were talk...

The latest planning chart shows ion setup starting on 3rd, 4th or 5th of Novemeber depending on how quickly they can collect pp data. Ion physics is due to run from 11th November until 6th December. Obviously these dates can change depending on how things go.

On Nov 5th they stop proton physics and switch to heavy Ion physics. Then on 6th Dec they close down for the winter until February. There will be meetings in Evian and Chamonix to thrash out a plan for next year.

Kasuha wrote: LHC is designed for as low as 50 ns spacing but getting there will take some time.

The nominal spacing is 25ns, and 50ns spacing may start this week.

I think AFS stands for Active Filling Scheme

There was a lot more info about the UFOs on Myers' recent talk http://indico.cern.ch/conferenceDisplay ... fId=105780 slides 22-27 but see the video for the full story.

To put more than 384 bunches in they need to decrease the separation again. That would require more setting up and there isnt time for it. It is better to run as much as possible with 384 bunches to get as much data as possible before they have to stop.

They are now on the third good run with 104 bunches, which qualifies them to go to the next step. They seem to keep changing their mind about how long to make the bunch trains. Last week the plan was to start with 8 bunches per train, then 12 then 24. They wanted to keep the number of injections bel...

ALICE is designed to study the heavy ion collisions that will run in Novemeber, so it does not need high luminosity now. They have configured the fill to give it just 8 bunch collisions per turn compared to 93 for the others, plus they have offset the beams so they only just collide.

Last fill was a bit rubbishy, but it doesn't seem to matter. Next fill 104 bunches ...

20/μb/s at peak, that's twice the previous record.