2016 operation

The place to discuss the LHC. Commissioning, operation, issues, events ....
jmc2000
Posts: 152
Joined: Sun May 08, 2011 2:51 pm

Re: 2016 operation

Post by jmc2000 » Mon Sep 26, 2016 4:14 pm

Record luminosities for Atlas: 13.75 Hz/nb, CMS: 14.5 Hz/nb !!

The latest LHCC meeting makes for interesting reading:
https://indico.cern.ch/event/563488/

page 14: https://indico.cern.ch/event/563488/con ... 1_LHCC.pdf

"~40-45 fb-1/year in 2017 and 2018 (goals fixed at Chamonix 2017)
- max peak luminosity ~1.7e34 cm-2s^-1
limited by inner triplets"

JMc

mfb
Posts: 168
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2016 operation

Post by mfb » Mon Sep 26, 2016 11:36 pm

The machine operators have shown a lot of creativity to improve the luminosity this year, despite various limitations (SPS beam dump, injection, ...). And the availability is just amazing.

With 35-40/fb this year and 40-45 in 2017 and 2018 we get ~1/4 more than the earlier plan of 100/fb for run 2.

mfb
Posts: 168
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2016 operation

Post by mfb » Sun Oct 09, 2016 2:48 pm

The last MD block is over, 17 more days for pp physics until the LHC switches to heavy ions. CMS quotes 34.1/fb delivered, ATLAS 31.9/fb. Looks like both experiments will end up with more than 35/fb, with CMS potentially reaching 40/fb. We'll see how much of this difference is just calibration and how much is an actual difference in collisions. Luminosity is excellent again.

Edit Oct15: ~130% design lumi for ATLAS, ~150% for CMS.

mfb
Posts: 168
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2016 operation

Post by mfb » Sat Oct 15, 2016 11:39 am

They made a high pileup test yesterday. Bunch trains with ~50 collisions per interaction, and a few individual bunches with 90-95 collisions. That is about 4 times the design value, and not far away from the HL-LHC conditions (140, maybe up to 200).

470/510 /pb after 16 hours so far, injector problems and still above 50% design luminosity. Could become another record if the injector problems persist (to beat: 720/pb in a fill), otherwise they'll dump and re-fill which is more efficient.

Edit 20:05 CERN time: Dumped. 567/616 /pb after nearly 24 hours (new 24h-record maybe?), down to 38% design luminosity at the end.

23:40: Back to stable beams, 124%/136% design luminosity.

jmc2000
Posts: 152
Joined: Sun May 08, 2011 2:51 pm

Re: 2016 operation

Post by jmc2000 » Mon Oct 17, 2016 12:15 am

mfb wrote:They made a high pileup test yesterday. Bunch trains with ~50 collisions per interaction, and a few individual bunches with 90-95 collisions. That is about 4 times the design value, and not far away from the HL-LHC conditions (140, maybe up to 200).
Has anything been published about this?

JMc


mfb
Posts: 168
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2016 operation

Post by mfb » Fri Oct 21, 2016 8:51 pm

The LHC now tests lumi levelling for ATLAS and CMS.

"That won't work for LHCb and disturb the beams for our own measurements" -> "Well, let's try, it might work" -> "Okay that works for LHCb, fine" -> "Hmm, that could be interesting for us" -> "We also want it" ;)

mfb
Posts: 168
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2016 operation

Post by mfb » Wed Oct 26, 2016 9:45 pm

And done.... last run with proton-proton collisions was dumped half an hour ago. 40/fb (CMS quotes 41.5, ATLAS 38.5) for the high-pileup experiments, 1.9/fb for LHCb. The dataset not shown at ICHEP exceeds the datasets of everything shown up to ICHEP for nearly every analysis in all three mentioned experiments.

Two weeks of MD/TS/Ion setup, then three weeks of proton-lead collisions at a record energy, then extended end-of-year shutdown, with proton-proton collisions resuming in May.

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