What are the current records for LHC fills?

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sciing
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Re: What are the current records for LHC fills?

Post by sciing » Wed Jun 15, 2016 8:44 pm

Reading the article, I just wonder which data will be used for the summer conferences, when will be the deadline?
With 3 >400/pb runs in a row, I guess at the end of the week they will far above 5/fb. They will run than 5 other weeks without longer stops. At the actual great pace (I guess some people at CERN can't stop grining at moment), they could even achieve 15/fb till then.
Quite a bunch of data to confirm the 750GeV signal;-)

jmc2000
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Re: What are the current records for LHC fills?

Post by jmc2000 » Wed Jun 15, 2016 11:17 pm

sciing wrote:Reading the article, I just wonder which data will be used for the summer conferences, when will be the deadline?
With 3 >400/pb runs in a row, I guess at the end of the week they will far above 5/fb. They will run than 5 other weeks without longer stops. At the actual great pace (I guess some people at CERN can't stop grining at moment), they could even achieve 15/fb till then.
Quite a bunch of data to confirm the 750GeV signal;-)
The aim is to get as much integrated luminosity as possible by July 15th so the data can be analyzed and presented in time for ICHEP in early August:

https://profmattstrassler.com/2016/06/0 ... s-the-lhc/

I thought the 2/fb/week record was a fluke, and things would quickly settle down to a more realistic 1.5/fb/week; but it looks as if the LHC is indeed managing to stay in SB for >60% of time compared to 30% last year giving 2/fb/week. Amazing!

JMc

mfb
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Re: What are the current records for LHC fills?

Post by mfb » Fri Jun 17, 2016 1:55 pm

Note that the July 15 is just the guess of this theorist. The experimental collaborations will have to see how much data they can include while keeping enough time for a proper analysis. We have two relevant data-points:
- The Higgs discovery included data taken two weeks before the presentation was given, but not in every channel presented - that was THE high-profile analysis for both ATLAS and CMS, so they probably pushed for every day they can include.
- The December 2015 presentation was scheduled for 6 weeks after the end of data-taking, which means both collaborations expected to have preliminary results with many searches by then.

6 weeks before ICHEP would be next week, 2 weeks before ICHEP would be July 19. The answer is probably somewhere in between, and depending on the analysis, in general analyses that are considered to be more important will include more data with more manpower.

sciing
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Re: What are the current records for LHC fills?

Post by sciing » Sat Jun 18, 2016 7:48 am

https://indico.cern.ch/event/442390/con ... P16_EM.pdf
Mid july was just mentioned this week on the LHCP with a target of >5/fb, mission accomplished today and still 3-4 weeks to go. So I think it is not unrealistic to see recorded 15/fb used (combined with 2015) at ICHEP.

mfb
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Re: What are the current records for LHC fills?

Post by mfb » Sat Jun 18, 2016 12:37 pm

~3 last year, 5 this year, would be 7 to go in a month or less. Not impossible, but not easy either. But independent of the final number, it should be sufficient to see what happens to the diphoton excess.

Some LINAC2 issues lead to a lower luminosity for the current fill, let's hope they fix that soon.

tomey36
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Re: What are the current records for LHC fills?

Post by tomey36 » Sun Jun 19, 2016 10:27 am

Does anyone know why they didn't record the integrated luminosity for fill 5024? They are missing about 200pb for Atlas and CMS. It just seems strange they didn't enter it.

Also what an awesome week of running, I hope things continue on this way :)

mfb
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Re: What are the current records for LHC fills?

Post by mfb » Mon Jun 20, 2016 11:17 pm

Huh? It is in the overview and also in the supertable for me.

~6.1/fb so far, 1.5 times the 2015 dataset. The combined 10/fb also mean that we should surpass the statistics of nearly every 8 TeV result now, as most cross sections increase by a factor of 2 or more.

ATLAS shows 450/pb for the current run and the luminosity is still good, probably gives another 0.5/fb+ run.

tomey36
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Re: What are the current records for LHC fills?

Post by tomey36 » Mon Jun 20, 2016 11:40 pm

I swear i am not crazy, as of yesterday it wasn't included. How are you getting 6.1fb? The overview page shows 5.85fb for Atlas. If you include the current fill it would be ~6.3 fb. Just curious in case you know of a more accurate place for lumi data than the statistics page.

sciing
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Re: What are the current records for LHC fills?

Post by sciing » Tue Jun 21, 2016 4:54 am

Quite actual online lumi
https://lpc.web.cern.ch/lumiplots_2016_pp.htm

CMS, also plots with corrected (offline) lumi, but slower update.
https://twiki.cern.ch/twiki/bin/view/CM ... licResults

BTW: 5030 is going to be a new record fill, past 525/pb for Atlas and almost 500/pb for CMS.

mfb
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Re: What are the current records for LHC fills?

Post by mfb » Wed Jun 22, 2016 12:38 pm

tomey36 wrote:I swear i am not crazy, as of yesterday it wasn't included. How are you getting 6.1fb? The overview page shows 5.85fb for Atlas. If you include the current fill it would be ~6.3 fb. Just curious in case you know of a more accurate place for lumi data than the statistics page.
I included the (then) current run and averaged over the CMS and ATLAS values. The true luminosity is probably between the two values, both experiments should have very similar actual luminosities.

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Tau
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Re: What are the current records for LHC fills?

Post by Tau » Sun Jun 26, 2016 6:04 am

And, after some "interesting" troubles last week, we are getting another record fill: 5043. As I write this, we already have .55/fb.

Reading tip, not for the faint of heart: if you are not afraid of some though math, this article shows exactly what are the troubles of the ADJUST phase (I never understood why this takes so long). The way the beams interact with each other is more complicated than I thought.
https://infoscience.epfl.ch/record/2046 ... TH6321.pdf
Tip: read "accelerators for pedestrians" first, otherwise you won't get very far.
- Tau

sciing
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Re: What are the current records for LHC fills?

Post by sciing » Mon Jun 27, 2016 7:31 am

New lumi record, Atlas 1.08 e34, design target reached.

tomey36
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Re: What are the current records for LHC fills?

Post by tomey36 » Mon Jun 27, 2016 10:11 am

so what happens when they reach 2088 bunches injected.

mfb
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Re: What are the current records for LHC fills?

Post by mfb » Mon Jun 27, 2016 11:29 am

sciing wrote:New lumi record, Atlas 1.08 e34, design target reached.
Even the average between ATLAS and CMS was slightly (~1%) above 1E34. They changed the SPS injection a bit, instead of one train with 72 bunches they injected two trains with 48 bunches each, that reduced the heat load on the LHC dipole magnets, which allowed to put more protons in each bunch.

The design value is 2808 bunches, ~2750 are possible with LHC limitations, so we still have ~35% possible improvement just from the number of bunches, if (a) the SPS vacuum leak gets fixed and (b) the heat load in the dipole magnets goes down sufficiently. Everything beyond that will need some clever tricks from the operators, or hardware upgrades.
It has BBQ data (Figure 5.3)


The current run is at 0.5/fb already, and still at 50% the design luminosity. Chances are good that we get another record (breaking the 0.58/fb run record from yesterday in 4-5 hours). See slide 22 of today's morning meeting: the plan is to beat all records!

Edit 17:30: 567/pb for ATLAS, 540/pb for CMS, 43% design luminosity after about 24 hours. Given the excellent performance with the last few turnaround times, it might be more efficient to dump and refill.
Edit 18:30: 583/pb for ATLAS, 556/pb for CMS, new records, 42% design luminosity.

jmc2000
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Re: What are the current records for LHC fills?

Post by jmc2000 » Mon Jun 27, 2016 4:50 pm

mfb wrote:
sciing wrote:New lumi record, Atlas 1.08 e34, design target reached.
Even the average between ATLAS and CMS was slightly (~1%) above 1E34. They changed the SPS injection a bit, instead of one train with 72 bunches they injected two trains with 48 bunches each, that reduced the heat load on the LHC dipole magnets, which allowed to put more protons in each bunch.
What would be the effect of increasing the bunches to 144 and 288 on the heat load?

Regards,

JMc

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