LHC portal

The cryogenics page now indicates green status for all sectors while the coordination page indicates hardware commissioning and machine checkout are in progress until 21st Feb when we expect first beams for 2011, oh it just changed to "Prepare LHC for beam" with more details for next week: http://op-webtools.web.cern.ch/op-webto ... r=LHCCOORD

There was a summary session on 9th Feb following the Chamonix workshop that descirbes how they intend to proceed see http://indico.cern.ch/getFile.py/access ... fId=126218

As we all now know they will stick with 3.5TeV this year but they also say "Thermal amplifier to be developped during 2011 to allow measurements during Christmas shutdown for a deterministic decision on a possible energy increase for 2012."

Bunch spacing for physics is expected to be 75ns compared to 150ns last year. They will use 50ns for scrubbing runs to try and remove the UFOs and e-clouds. If that works really well they may even use 50ns for physics later. Beta* for the squeeze could go down to 1.5m compared with last years 3.5m. That seems ambitious given that they are sticking at 3.5TeV which makes the squeeze harder. These changes imply an improvement in luminosity by a factor of 7 maximum. Realistically they want to get back to last years record of 0.2/nb/s as quickly as possible and then build up slowly to 1.0/nb/s. They hope for 124 days of high luminosity. If they can run at 30% efficiency for those days with 1.0/nb/s they will collect 3/fb during 2011. The official target remains at 1/fb but 3/fb is not unrealistic. Observation of new physics is quite possible but not guaranteed with this much data. A similar amount collected during 2012 should be enough to get some indication of where Higgs lives.

CERN has a new blog at quantum diaries: http://www.quantumdiaries.org/author/cern/
Other best blogs to follow for LHC news are:
viXra Log: http://blog.vixra.org/
the reference frame: http://motls.blogspot.com/
US LHC: http://www.uslhc.us/
Quantum Diaries Survivor: http://www.science20.com/quantum_diaries_survivor
Resonaaces: http://resonaances.blogspot.com/

Not to mention this forum and of course there are lots of useful links on The Portal.

The portal's LHC "Progress" link needs to be updated. The new link is:

http://lhc-commissioning.web.cern.ch/lh ... -news.html

great post phill i have been looking for a summary like that for a while now. You get

First beam planned for 18th according to the CERN Bulletin.

http://cdsweb.cern.ch/journal/CERNBulle ... es/1327612

Beam Mode = Setup !

Getting closer . .

According to the coordination page they have injection studies this afternoon and first circulating beams tomorrow (Sunday 20th Feb)

Need to fix link on LHC Progress.
http://lhc-commissioning.web.cern.ch/lh ... -news.html

Can get to it noow by LHC->Corrdination->2011 LHC Operation Latest News

There's beam in the machines !!

DCWhitworth wrote:There's beam in the machines !!

Over the weekend they succeeded in squeezing down to beta* of 1.5m . Remember last year they only went to 3.5m so this is a big step forward. It will at least double the luminosity. According to the Sunday morning meeting report there were some problems with changes in the crossing angle bump during the squeeze in LHCb which could make life difficult.

They've squeezed to 1.5m but there are still issues to overcome if I understand the morning meeting notes.

Nice to see they've identified the cause of the debunch issue, that looked a little worrying for a bit.

I noticed that the squeez to 1.5 meters isonly in Atlas and CMS i know Alice is useing differnt settings but why is the squeez in Lhcb only 3 meters? have they not gotten to it yet, or is 3m its maximum value?

Alice may not need that much of squeezing. For LHCb I guess they are not there yet.

The choice of Beta* for Alice and LHCb is optimized for their required luminosities. There is a maximum luminosity that LHCb can cope with - 2-3x10+32. When the potential performance exceeds this, separation will be used to keep the luminosity at around this value. Having a lower Beta* would just mean that more separation would be needed to keep the luminosity reasonable. In fact the separation can be changed as a fill goes on in such a way as to keep an almost constant luminosity.

Similar arguments apply to Alice - except that their luminosity limit is 100 times smaller! Staying at 10m Beta* therefore makes sense. The only down side here is that a squeeze for Alice will have to be commissioned as part of the set-up for the ion run at the end of the year.

so, 1.5,10,1.5,3 are the nominal Beta* for this year in physics.

Thanks pcatom that clears things up nicely for me