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LuminosityPublicResultsRun2

Introduction

Here any results related to ATLAS luminosity measurements in Run-2 are given. For Run-1 results, please see Luminosity Results for Run-1 (2010-2012).

Publications and Conference Results

Luminosity:

Satellite Bunches:

Luminosity summary plots for 2015 data taking

These plots show the estimated integrated luminosity with the most recent offline calibration. (July 2015)

Total Integrated Luminosity in 2015
Cumulative luminosity versus time delivered to (green) and recorded by ATLAS (yellow) during stable beams for pp collisions at 13 TeV centre-of-mass energy in 2015. The delivered luminosity accounts for luminosity delivered from the start of stable beams until the LHC requests ATLAS to put the detector in a safe standby mode to allow for a beam dump or beam studies. The recorded luminosity reflects the DAQ inefficiency, as well as the inefficiency of the so-called ‘warm start’: when the stable beam flag is raised, the tracking detectors undergo a ramp of the high-voltage and, for the pixel system, turning on the preamplifiers. Shown is the luminosity as determined from counting rates measured by the luminosity detectors. These detectors have been calibrated with the use of the van-der-Meer beam-separation method, where the two beams are scanned against each other in the horizontal and vertical planes to measure their overlap function. The luminosity shown represents the preliminary 13 TeV luminosity calibration.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/sumLumiByDay.png
pdf file
Integrated Luminosity by Day in 2015
Integrated luminosity per day time delivered to (green) and recorded by ATLAS (yellow) during stable beams for pp collisions at 13 TeV centre-of-mass energy in 2015. The data shown is identical to the data shown above, except not cumulative over the year.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/lumiByDay.png
pdf file
Peak Luminosity per Fill in 2015
The peak instantaneous luminosity delivered to ATLAS during stable beams for pp collisions at 13 TeV centre-of-mass energy is shown for each LHC fill as a function of time in 2015. The luminosity is determined using counting rates measured by the luminosity detectors, and is based on a preliminary 13 TeV calibration determined using van-der-Meer beam-separation scans.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/peakLumiByFill.png
pdf file
Peak Interactions per Crossing in 2015
The maximum number of inelastic collisions per beam crossing (µ) during stable beams for pp collisions at 13 TeV centre-of-mass energy is shown for each fill in 2015. The online luminosity measurement is used to determine the number of interactions per beam crossing as µ = Lbunch x σinel / fr where Lbunch is the per-bunch instantaneous luminosity, σinel is the inelastic cross-section at 13 TeV, which is taken to be 80 mb, and fr is the LHC revolution frequency of 11.245 kHz. The number of interactions shown is averaged over all colliding bunch pairs, and only the peak value per fill during stable beams is shown.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/peakMuByFill.png
pdf file

Annual plots

They are based on the online luminosity determination

2015 pp Collisions

Pileup Interactions and Data Taking Efficiency

Number of Interactions per Crossing
Shown is the luminosity-weighted distribution of the mean number of interactions per crossing for the 2015 pp collision data recorded from 3 June - 20 July at 13 TeV centre-of-mass energy. All data delivered to ATLAS during stable beams is shown, and the integrated luminosity and the mean mu value are given in the figure. The mean number of interactions per crossing corresponds to the mean of the poisson distribution of the number of interactions per crossing calculated for each bunch. It is calculated from the instantaneous per bunch luminosity as μ=Lbunch x σinel / fr where Lbunch is the per bunch instantaneous luminosity, σinel is the inelastic cross section which we take to be 80 mb for 13 TeV collisions, and fr is the LHC revolution frequency.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/mu_2015.png
pdf file
eps file
Data Taking Efficiency per Day
ATLAS data taking efficiency in 2015. The denominator is the luminosity delivered between the declaration of stable beams and the LHC request to turn the sensitive detectors off to allow a beam dump or beam studies. The numerator is the luminosity recorded by ATLAS. Each bin represents one day. The empty bins are due to days in which no stable beams were delivered by the LHC. The inefficiency accounts for the time needed to turn on the high-voltage of the Pixel, SCT, and some of the muon detectors at the start of an LHC fill and any inefficiencies due to deadtime or due to individual problems with a given sub detector that prevents the ATLAS data taking to proceed.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/recEffByDay.png
pdf file
Data Taking Efficiency per Week
Same as above but per week.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/recEffByWeek.png
pdf file

Detailed Additional Luminosity related Information


Major updates:
-- EricTorrence - 2015-07-20

Responsible: EricTorrence
Subject: public

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Topic revision: r3 - 2015-07-22 - EricTorrence
 
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