2018 Operation

The place to discuss the LHC. Commissioning, operation, issues, events ....
andrewp
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Re: 2018 Operation

Post by andrewp » Thu May 17, 2018 9:15 am

I raise my beer to the unsung Operator heroes!

andrewp
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Re: 2018 Operation

Post by andrewp » Sun May 20, 2018 6:05 am

16L2 wreaking havoc once more. Maybe clean it out for good?

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trobbins
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Re: 2018 Operation

Post by trobbins » Wed May 23, 2018 7:38 am

Performance is certainly trending sky high:
https://twiki.cern.ch/twiki/bin/view/CM ... year_plots

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Tau
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Re: 2018 Operation

Post by Tau » Wed May 23, 2018 12:46 pm

Here you can see that they are at about twice the predicted performance... not bad. (That was at the time I posted this, which was May. The updated graph will of course change, and I can't predict what it looks like when you read this.)
https://twiki.cern.ch/twiki/pub/LhcMach ... -model.png
This picture is from the coordination page (scroll down to find it):
https://twiki.cern.ch/twiki/bin/view/Lh ... nationMain
- Tau

andrewp
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Re: 2018 Operation

Post by andrewp » Sun Jun 03, 2018 5:49 pm

There have since been a raft of subsequent faults, all different in nature. The latest is a pair of cryo failures.

jmc2000
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Re: 2018 Operation

Post by jmc2000 » Sun Jun 03, 2018 11:42 pm

134th LHCC Meeting - Agenda OPEN Session
https://indico.cern.ch/event/726320/

Aiming for ~60\fb for 2018

JMc

dukwon
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Re: 2018 Operation

Post by dukwon » Mon Jun 04, 2018 11:11 am

gruffalo.png
gruffalo.png (168.8 KiB) Viewed 893 times
The gruffalo with his hand on the beam dump switch

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Tau
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Re: 2018 Operation

Post by Tau » Tue Jun 05, 2018 6:51 am

Aha, so that causes unexpected dumps!
Looks a lot more plausible than birds dropping sandwiches in ventilation ducts https://cds.cern.ch/journal/CERNBulleti ... es/1221806 or a hump https://vixra.wordpress.com/2010/07/16/ ... erference/.
- Tau

jlourenc
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Re: 2018 Operation

Post by jlourenc » Thu Jun 07, 2018 8:06 am

Hi
Can anyone explain why Atlas isn’t getting the same lumi as CMS and shed some light into what happened with the magnet?
Thanks
Joao

dukwon
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Re: 2018 Operation

Post by dukwon » Thu Jun 07, 2018 8:52 am

ATLAS requested the lower lumi. I'm guessing there's little point stressing the computing resources collecting high-pileup data with the magnet off. I'll try to find out what the problem with the magnet is, although I'm sure mfb will tell us soon enough.

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Re: 2018 Operation

Post by dukwon » Thu Jun 07, 2018 9:14 am

From what I've heard, it was shut down on purpose to do a special run for the liquid argon calorimeter. I'm not sure I believe that.
Last edited by dukwon on Fri Jun 08, 2018 8:02 am, edited 1 time in total.

dukwon
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Re: 2018 Operation

Post by dukwon » Thu Jun 07, 2018 2:44 pm

8 quenches in S34. 12–15 hours to wait for cryo recovery :(

andrewp
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Re: 2018 Operation

Post by andrewp » Sat Jun 09, 2018 4:42 pm

andrewp wrote:
Sat May 12, 2018 10:09 pm
Looks like the current run (#6675) will smash all previous LHC records for sustainable integrated lumi per 24 hour period - at least 1/fb. :dance:

Notionally this consists of 2 switchovers (time of dump to time of next stable beams) and 2 runs. The switchovers can be 2 hours each and the runs can be 10 hours each. Each run can deliver 0.5/fb.
This performance has not been repeated since - yet. Fingers crossed.

andrewp
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Re: 2018 Operation

Post by andrewp » Sun Jun 10, 2018 9:59 pm

New switchover record! Run #6773->6774 took 1h23m !! (dump->SB).
Good lumi too, so we shall see...

dukwon
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Re: 2018 Operation

Post by dukwon » Mon Jun 11, 2018 9:08 am

21:39 to 23:55 is 2 hours, 16 minutes. I believe the theoretical minimum turnaround time is about 1h45m.

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