Search found 135 matches

by PhilG
Sat Aug 11, 2012 6:19 pm
Forum: The Accelerator
Topic: 2012 Events Discussion
Replies: 100
Views: 80556

Re: 2012 Events Discussion

If I understood the latest news correctly CMS lost the current in its solenoid and temperature went up to 70K. It will take 5 days to get back to normal so they will not be doing physics runs much until it is sorted.

If anyone knows more please fill us in.
by PhilG
Sat Apr 28, 2012 2:17 pm
Forum: The Accelerator
Topic: amazing luminosity?
Replies: 1
Views: 1311

Re: amazing luminosity?

The figure is roughly correct although the luminosity still needs calibration
Even last year they got to 123000/nb in one fill, but it took 15 hours. This new record was done in under 10.
by PhilG
Fri Apr 27, 2012 6:18 pm
Forum: New Users Start Here
Topic: Have they ...?
Replies: 5
Views: 2365

Re: Have they ...?

A) These are emergent particles, collective behaviour in condensed matter systems. They can't exist in this form outside if spin ice. Real fundamental magnetic monopoles may well exist according to some GUT theories. They are expected to be too heavy to produce at the LHC but the experiments still s...
by PhilG
Sat Apr 21, 2012 7:12 am
Forum: The Accelerator
Topic: Why is there a difference in the Cms and Atlas luminosities?
Replies: 9
Views: 2920

Re: Why is there a difference in the Cms and Atlas luminosit

PhilG wrote:Not overnight but maybe over a couple of nights. They are aiming for 1.45 E11 now!
They didn't get it to work but nice try.
by PhilG
Fri Apr 20, 2012 9:49 pm
Forum: The Accelerator
Topic: Why is there a difference in the Cms and Atlas luminosities?
Replies: 9
Views: 2920

Re: Why is there a difference in the Cms and Atlas luminosit

Not overnight but maybe over a couple of nights. They are aiming for 1.45 E11 now!
by PhilG
Thu Apr 19, 2012 6:13 am
Forum: The Accelerator
Topic: Why is there a difference in the Cms and Atlas luminosities?
Replies: 9
Views: 2920

Re: Why is there a difference in the Cms and Atlas luminosit

Last year they reached 3.5/nb/s with beta* = 1.0 so with beta* = 0.6 they should expect 3.5/0.6 = 5.8/nb/s assuming intensity and emittance are the same. So the CMS figure looks better.
by PhilG
Wed Apr 18, 2012 9:21 pm
Forum: The Accelerator
Topic: Why is there a difference in the Cms and Atlas luminosities?
Replies: 9
Views: 2920

Re: Why is there a difference in the Cms and Atlas luminosit

It could simply be that they have not finished analysing the scans yet
by PhilG
Tue Apr 17, 2012 9:14 am
Forum: The Accelerator
Topic: 2012 Events Discussion
Replies: 100
Views: 80556

Re: 2012 Events Discussion

@adam_jeff, your point is valid but even taking that into account the stability and turn-round times have been exceptionally good compared to last year. The beams have been dumped at around 50% of peak lumi as they often were in 2011 if they lasted. This is quicker now because the luminosity half-li...
by PhilG
Fri Jan 06, 2012 8:19 pm
Forum: Science
Topic: The Hunt for Higgs: A Horizon Special
Replies: 2
Views: 1568

The Hunt for Higgs: A Horizon Special

If you are in the UK, dont miss this on Monday 9th Jan 21:00 BBC2 and BBC HD.

http://www.bbc.co.uk/programmes/b019h7t0
by PhilG
Sun Oct 30, 2011 8:04 am
Forum: The Accelerator
Topic: LHC Proton Physics runs for 2011 now complete.
Replies: 5
Views: 2524

Re: LHC Proton Physics runs for 2011 now complete.

There is one more proton physics run in progress now, possibly the last this year. For detailed summaries look our for EVIAN 2011 Beam Operation Workshop http://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=155520 Mike Lamont will also be delivering the John Adams Lecture on 18th Novem...
by PhilG
Sat Oct 29, 2011 8:01 am
Forum: The Accelerator
Topic: LHC Proton Physics runs for 2011 now complete.
Replies: 5
Views: 2524

Re: LHC Proton Physics runs for 2011 now complete.

They still plan some more proton physics until sunday afternoon
by PhilG
Wed Oct 12, 2011 6:27 am
Forum: The Accelerator
Topic: High pile-up MD
Replies: 2
Views: 3720

Re: High pile-up MD

Hopefully they will not have to use luminosity leveling until much later except for LHCb and ALICE that already use it. The pile-up MD will collide a small number of high intensity bunches to increase the pile-up. This will give CMS and ATLAS some data to test and improve their reconstruction algori...
by PhilG
Fri Sep 16, 2011 8:47 pm
Forum: The Accelerator
Topic: Presentation for the Grid for UK Particle Physics
Replies: 5
Views: 2190

Re: Presentation for the Grid for UK Particle Physics

Talking of LHC status reports, next week there is an LHCC open session which starts with an LHC status report by someone familiar http://indico.cern.ch/conferenceDisplay ... fId=153317
by PhilG
Fri Sep 16, 2011 5:07 pm
Forum: The Accelerator
Topic: What's the maximum bunch intensity they can go for?
Replies: 5
Views: 3000

Re: What's the maximum bunch intensity they can go for?

For now the main limiting factor is actually the cryogenics. With 50ns spacing they can go to about 1.7E11 before the cooling rate required from the cryogenics is too much. The exact amount may depend on the e-cloud build-up and such. They injected bunches with over 2E11 during MD so the injectors a...