2011 Events Discussion

The place to discuss the LHC. Commissioning, operation, issues, events ....
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PhilG
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Re: 2011 Events Discussion

Post by PhilG » Thu Jun 16, 2011 2:58 pm

zaim wrote:Just now the LHC surpassed 0.5 fb^-1 integrated luminosity delivered to CMS.
Current fill of 32 pb^-1 plus the 468 ps^-1 stated here https://twiki.cern.ch/twiki/bin/view/CM ... licResults
Just 17 days later and they have doubled that to 1/fb
https://lhc-statistics.web.cern.ch/LHC-Statistics/

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Bornerdogge
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Re: 2011 Events Discussion

Post by Bornerdogge » Sat Jun 18, 2011 9:47 am

Looks like they're going for the next step - 1236b - this afternoon, at last!

tomey36
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Re: 2011 Events Discussion

Post by tomey36 » Tue Jun 21, 2011 4:24 am

or not :( i was excited aswell, i guess they wanted to do one more run to check for any problems after the cryo loss. hoping for tomorrow :)

oldboson
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Re: 2011 Events Discussion

Post by oldboson » Tue Jun 21, 2011 4:10 pm

New production record on a single fill here... #1883 ATLAS yield >47 pb-1 and counting...

Kinda they postponed dumping (15pm, then 18pm, now 18.30pm...) to get a new record, well done guys, the machine is running smoothly!
Oldboson.

conrad
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Re: 2011 Events Discussion

Post by conrad » Tue Jun 21, 2011 5:55 pm

What are -RF problems? What does RF stand for? Why, after 18 hours to prepare, can't the SPS have a beam? a newbie.

Kasuha
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Re: 2011 Events Discussion

Post by Kasuha » Tue Jun 21, 2011 6:49 pm

conrad wrote:What are -RF problems? What does RF stand for? Why, after 18 hours to prepare, can't the SPS have a beam? a newbie.
RF stands for "Radio Frequency" I believe and it means the high frequency cavities (klystrons) which are accelerating the beam and keeping it organized in bunches.

Postponing beam dump in case there is technical problem on SPS is normal - without SPS they cannot refill.

pjotertje
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Re: 2011 Events Discussion

Post by pjotertje » Wed Jun 22, 2011 9:49 am

Now.
Protestation movement
no beam, no access

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Wed Jun 22, 2011 12:13 pm

pjotertje wrote:Now.
Protestation movement
no beam, no access
Ummm, what ? Page 1 says access ongoing.
DC

The LHC - One ring to rule them all !

pjotertje
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Re: 2011 Events Discussion

Post by pjotertje » Wed Jun 22, 2011 12:42 pm

DCWhitworth wrote:
pjotertje wrote:Now.
Protestation movement
no beam, no access
Ummm, what ? Page 1 says access ongoing.
That was this morning on CPS page!!

StevieB
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Re: 2011 Events Discussion

Post by StevieB » Wed Jun 22, 2011 1:18 pm

pjotertje wrote:
DCWhitworth wrote:
pjotertje wrote:Now.
Protestation movement
no beam, no access
Ummm, what ? Page 1 says access ongoing.
That was this morning on CPS page!!

Something to do with this maybe?

http://cdsweb.cern.ch/journal/CERNBulle ... 7595?ln=en

adam_jeff
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Re: 2011 Events Discussion

Post by adam_jeff » Wed Jun 22, 2011 3:14 pm

pjotertje wrote:
DCWhitworth wrote:
pjotertje wrote:Now.
Protestation movement
no beam, no access
Ummm, what ? Page 1 says access ongoing.
That was this morning on CPS page!!
There was a 4 hour work stoppage by CERN staff this morning in protest at proposed changes to their pension scheme. I don't know how many people took part or what effect it had on the operation of the various machines though.

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Fri Jun 24, 2011 8:07 am

Now filling with 1236 bunches - at last ! :dance:
DC

The LHC - One ring to rule them all !

jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Fri Jun 24, 2011 6:03 pm

DCWhitworth wrote:Now filling with 1236 bunches - at last ! :dance:
Watch for the spikes in the beam size when filling. It's usually a good indication of things being amiss.

conrad
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Re: 2011 Events Discussion

Post by conrad » Sun Jun 26, 2011 4:37 pm

In the last 24 hours there were 5 successful fills for physics. The average run was about 2 hours. Things kept going wrong. Is this just bad luck?

jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Sun Jun 26, 2011 6:18 pm

conrad wrote:In the last 24 hours there were 5 successful fills for physics. The average run was about 2 hours. Things kept going wrong. Is this just bad luck?
They had problems with vacuum in B2 IR4 dumping the beam three times before changing the threshold. I don't think it's anything to do with bad luck as such, but what happens when a large machine is being commissioned in unknown territory.

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