Search found 67 matches

by pcatom
Tue Aug 02, 2011 10:43 am
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

The portal points to an older version. The current schedule (and any updates to it) can be found at:

https://espace.cern.ch/be-dep/BEDepartm ... hedule.pdf
by pcatom
Thu Jun 09, 2011 6:53 pm
Forum: The Accelerator
Topic: Are the LHC team pleased with current performance reached?
Replies: 2
Views: 2584

Re: Are the LHC team pleased with current performance reache

So would I be right in saying that things are very successful at the moment, even if they are still sorting out current problems?
In short - yes!

To reach such a level of performance so quickly and with such a complex machine is impressive.
by pcatom
Sat May 28, 2011 8:46 pm
Forum: The Accelerator
Topic: Clock Distribution
Replies: 4
Views: 3564

Re: Clock Distribution

For the machine there are 2 timing systems, slow and fast ... the terms are relative ;) The slow system allows synchronization of events at the millisecond level. Here the Signals are broadcast - with tof delays built in (but not really so significant), the whole system is kept in synchronization wi...
by pcatom
Sat May 28, 2011 8:36 pm
Forum: The Accelerator
Topic: Are all interfaces to the ring optically coupled?
Replies: 9
Views: 4987

Re: Are all interfaces to the ring optically coupled?

Does anyone know if all the interfaces to the LHC ring are optically coupled? Because of the enormous changing magnetic field, I'd like to know how they deal with induced pick up. It appears that one of the PLCs had to be replaced that controls the cryogenics and perhaps a voltage spike killed it. ...
by pcatom
Sat May 28, 2011 8:28 pm
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

The 1092 filling scheme uses 108b per injection. It is pretty much the maximum that can be fitted in with 108b injection. The next step after that will be the same number of bunches with 144 bunch injection .... then onward and upward.
by pcatom
Thu May 26, 2011 5:00 pm
Forum: The Accelerator
Topic: The cost of days without runs
Replies: 5
Views: 3452

Re: The cost of days without runs

... a lot ...
by pcatom
Sun May 15, 2011 11:02 am
Forum: The Accelerator
Topic: The cryogenics at the LHC
Replies: 2
Views: 3393

Re: The cryogenics at the LHC

Over the past few weeks I've noticed that they might lose between 1/2-1 days on the cyrogenics failing. How good are the cryogenics at the LHC compared to the Tevatron? What are the problems with cryogenics upto now and how difficult have they been to fix? Which part of the tunnel is the least acce...
by pcatom
Thu May 12, 2011 4:46 pm
Forum: The Accelerator
Topic: Improved performance after MD and TS?
Replies: 11
Views: 5835

Re: Improved performance after MD and TS?

At the Tevatron, they've managed to limit 1 quench to around 20 fills. Do you know what the figure is for the LHC and if they have a realistic chance of reducing it? They were also managing to get remarkable fill times of 70% so I'm curious to know if the guys at Tevatron are consulting the LHC guy...
by pcatom
Tue May 10, 2011 6:34 pm
Forum: The Accelerator
Topic: Improved performance after MD and TS?
Replies: 11
Views: 5835

Re: Improved performance after MD and TS?

Dude your awesome! I just have one question, do have any information on the ATS studies they did. how are they differnt from the normal squeez operation? The minimum Beta* in the high luminosity IP's is limited by the aperture in the triplets, but also by the chromatic aberrations introduced by the...
by pcatom
Mon May 09, 2011 8:23 pm
Forum: The Accelerator
Topic: Improved performance after MD and TS?
Replies: 11
Views: 5835

Re: Improved performance after MD and TS?

I don't have any inside info and the planning meetings are restricted access now, but I understand that the plan is to keep stepping up bunches until they reach about 1380 using 50ns. There has not been much info about how all the MD tests will affect that plan. It was noticed that they tried out h...
by pcatom
Mon May 02, 2011 6:36 pm
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

Does anybody know what the "unsqueeze"-tests are good for?

Currently, b* is about 90m in CMS... (but with no beam in the machine)


Report this post
The 90m beta* optics is requested for Totem and Alfa. The first studies (with beam) will take place during the MD session starting on Wednesday.
by pcatom
Wed Apr 27, 2011 8:13 pm
Forum: The Accelerator
Topic: Newbie: Lumi difference between Atlas and CMS
Replies: 10
Views: 5631

Re: Newbie: Lumi difference between Atlas and CMS

It is suspected that Atlas are presently reading a little high. To calibrate the luminosity correctly the experiments need to do Van de Meer scans. This involves scanning the beams through each other over a wide range to establish the full luminous region as well as a good knowledge of the intensity...
by pcatom
Tue Apr 19, 2011 7:29 pm
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

Jose Barroso, President of the European Commission.
by pcatom
Sun Mar 20, 2011 3:16 pm
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

Thanks for all your comment and input. This forum is a great place for sharing information. Hope they can keep up the same production rates in the future. If so will make for a great year of data collection. We are hoping for a much higher production rate ... a factor 15 higher luminosity than at p...
by pcatom
Sun Mar 20, 2011 12:39 pm
Forum: The Accelerator
Topic: 2011 Events Discussion
Replies: 184
Views: 83570

Re: 2011 Events Discussion

The next step will be 136 bunches - hopefully this evening. This will use 24 bunch injection (plus a couple of 8 bunch injections). After that would be around 200 bunches. However, the plan is now to get the 1.38 TeV run out of the way before the technical stop. Expect a change to running like this ...