Search found 135 matches

by PhilG
Fri Dec 10, 2010 10:05 am
Forum: The Accelerator
Topic: The Hump
Replies: 20
Views: 12769

Re: The Hump

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.
by PhilG
Tue Nov 16, 2010 9:50 am
Forum: The Accelerator
Topic: Prospects for 2011 (via reuters)
Replies: 12
Views: 6111

Prospects for 2011 (via reuters)

Interesting and optimistic Reuters report on prospects for next year

http://feeds.reuters.com/~r/reuters/sci ... QU20101115
by PhilG
Tue Nov 16, 2010 9:48 am
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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.
by PhilG
Sun Nov 07, 2010 7:21 pm
Forum: The Accelerator
Topic: What to ask the LHC team about its operations or displays
Replies: 25
Views: 11342

Re: What to ask the LHC team about its operations or displays

Z means the atomic number which is 82 for lead, so the energy per ion is 3.5 x 82 TeV
by PhilG
Sun Nov 07, 2010 6:23 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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...
by PhilG
Tue Oct 26, 2010 7:26 am
Forum: The Accelerator
Topic: LHC to shut down for a whole year
Replies: 8
Views: 4872

Re: LHC to shut down for a whole year

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.
by PhilG
Mon Oct 25, 2010 9:42 am
Forum: The Accelerator
Topic: LHC to shut down for a whole year
Replies: 8
Views: 4872

Re: LHC to shut down for a whole year

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.
by PhilG
Mon Oct 25, 2010 9:34 am
Forum: The Accelerator
Topic: What to ask the LHC team about its operations or displays
Replies: 25
Views: 11342

Re: What to ask the LHC team about its operations or displays

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.
by PhilG
Sun Oct 24, 2010 6:51 am
Forum: The Accelerator
Topic: What to ask the LHC team about its operations or displays
Replies: 25
Views: 11342

Re: What to ask the LHC team about its operations or displays

I think AFS stands for Active Filling Scheme
by PhilG
Sun Oct 03, 2010 7:56 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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.
by PhilG
Tue Sep 28, 2010 4:30 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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.
by PhilG
Tue Sep 28, 2010 6:44 am
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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...
by PhilG
Sun Sep 26, 2010 7:06 am
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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.
by PhilG
Sat Sep 25, 2010 11:20 am
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

Last fill was a bit rubbishy, but it doesn't seem to matter. Next fill 104 bunches ...
by PhilG
Thu Sep 23, 2010 5:34 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 193150

Re: Current Events Discussion

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