2011 Events Discussion

The place to discuss the LHC. Commissioning, operation, issues, events ....
jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Mon Jul 18, 2011 8:52 pm

josch222 wrote:Dump! Arrgh, shit!, that would have been a record fill.
I saw very short a luminosity something about 1350Hz/µb and they had 100MJ/beam in,
obviously with more bunch intensity than the last fills.
I hope this was not an UFO, they only waited for 1/2h between injection and ramp this
time.
And the one after, fill 1958, got dumped as well, with a lower bunch intensity yet the instantaneous luminosity looks as if it got to above 1600Hz/ub! Maybe they lowered the emittance this time.

Where can I see the value for emittance?

josch222
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Re: 2011 Events Discussion

Post by josch222 » Mon Jul 18, 2011 9:35 pm

I have not seen a value in any of the Vistars or elsewhere for the running fiill
but here is a "supertable" with really a lot of parameters. I haven't looked at it in detail.
https://j2eeps.cern.ch/test-supertable/
You can export and download it as excel file and do your own statistics.

tomey36
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Re: 2011 Events Discussion

Post by tomey36 » Sat Jul 30, 2011 9:56 am

Man they were so close to 2000/ubs. It seems like every fill gives a little bit more luminoisty, i hope they can keep it up :)

tomey36
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Re: 2011 Events Discussion

Post by tomey36 » Sat Jul 30, 2011 9:22 pm

looks like they did manage 2000/ubs good stuff!

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Tim Bergel
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Re: 2011 Events Discussion

Post by Tim Bergel » Tue Aug 02, 2011 8:35 am

Has the schedule (as available from the portal) been revised? Unless I'm reading it incorrectly, we should be in the middle of a technical stop right now...

pcatom
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Re: 2011 Events Discussion

Post by pcatom » Tue Aug 02, 2011 10:43 am

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

pcatom
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Re: 2011 Events Discussion

Post by pcatom » Tue Aug 02, 2011 10:47 am

looks like they did manage 2000/ubs good stuff!
Record Peak luminosity is now around 2050 ub-1s-1

jmc2000
Posts: 153
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Re: 2011 Events Discussion

Post by jmc2000 » Wed Aug 03, 2011 3:14 pm

pcatom wrote:
looks like they did manage 2000/ubs good stuff!
Record Peak luminosity is now around 2050 ub-1s-1
And looks as if the machine is tuned to perfection right now, managing a turn around after an electrical glitch of just 2 hours, and a integrated luminosity within 24 hours of over 100/pb.

I'm amazed they've managed this by just reducing emittance which was supposed to have brought the luminosity up to 1300 ub/s at most.

Do you know if the problems with increased bunch intensity are understood, and to what level an increase might be possible?

There's also the reduction in beta* at the next technical stop which will increase the luminosity by 1.5 so what sort of luminosities will the machine be going for over the remaining year?

bgab001
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Re: 2011 Events Discussion

Post by bgab001 » Thu Aug 04, 2011 8:36 pm

Hi
I was watching the fill 2000 yesterday evening, and it did beat "a few" records again ! :clap:
- Max luminosity in one fill (90.78 pb-1 in Atlas)
- Max luminosity in one day (97.4)
- Max luminosity in 7 days (307.37)
- Longest fill (21.5 h)
- Longest time with stable beams in one day (21.9h)
- Fastest turnaround time (2.12h)

Too bad it didn't have the highest peak luminosity, it could have had even more record ;-)
And too bad these records won't even hold more than a few months again (at best) :-P

Well done!
B.

josch222
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Re: 2011 Events Discussion

Post by josch222 » Fri Aug 05, 2011 8:25 am

In the last minutes Atlas passed the 2 fb^-1 integrated Lumi.

Harbles
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Re: 2011 Events Discussion

Post by Harbles » Sat Aug 06, 2011 8:55 pm

And another record Fill #2006 One minute shy of 26 hours with over 100 (pb)^-1 integrated luminosity.
http://lhc-statistics.web.cern.ch/LHC-S ... index.html#

String 10 of those together and there's another inverse femto-barn!

jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Sat Aug 06, 2011 9:27 pm

Harbles wrote:And another record Fill #2006 One minute shy of 26 hours with over 100 (pb)^-1 integrated luminosity.
http://lhc-statistics.web.cern.ch/LHC-S ... index.html#

String 10 of those together and there's another inverse femto-barn!
Getting 3/fb looks on the cards over the next 2 weeks - what an achievement if they do it!, providing they don't go mad with pushing beam intensity and destabilising the running. I'm not sure why the're leaving it for so long in fill when the beam half life is 14 hours. Stringing along 12.5 18 hour 80/pb fills rather than 10 26 hour 100/pb fills would seem to be more efficient.

josch222
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Re: 2011 Events Discussion

Post by josch222 » Sat Aug 06, 2011 10:33 pm

There are some reason why they keep the fills for a long time:
Every filling process has its own risks, it seems to be not very stable at the moment.
A turn around time of 2h is a rare exception, usually they need much longer.
In the last weeks they had so much short fills, I think they are very happy to have
some lasting fills now to produce luminosity til the next MD/TS.
I think the experiments are not interested in fiddling the last bit of peak lumi
out of the machine too (that's what MD is for), they want stable beams to record
data.

Another reason may be some problems with SPS lately and the next one will be addressed
next week: They have to change a magnet (due to a vacuum leak) and this will last
20h. So I think it is good to have some experience in keeping long fills to bridge the time
without beam from SPS.

tomey36
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Re: 2011 Events Discussion

Post by tomey36 » Mon Aug 08, 2011 8:02 am

Well that was an exciting week, over 400 picobarns of data, and they broke pretty much every record they had. Lets hope they can keep it up!!!!

tomey36
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Re: 2011 Events Discussion

Post by tomey36 » Thu Sep 22, 2011 9:37 pm

Any one know why Atlas has been recording less collision data than CMS? In the last fill Atlas had 2 pb and CMS had over 40 pb.

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