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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 2016 pp data taking

These plots show the estimated integrated luminosity with the initial online calibration.

Total Integrated Luminosity in 2016
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 2016. 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. The initial calibration for these detectors for 2016 is taken from the previous year as determined in December 2015.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2016/DataSummary/figs/sumLumiByDay.png
pdf file
Integrated Luminosity by Day in 2016
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 2016. 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/2016/DataSummary/figs/lumiByDay.png
pdf file
Peak Luminosity per Fill in 2016
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 2016. The luminosity is determined using counting rates measured by the luminosity detectors, and is based on an initial 13 TeV calibration determined using the December 2015 result from the previous year.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2016/DataSummary/figs/peakLumiByFill.png
pdf file
Peak Interactions per Crossing in 2016
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 2016. The preliminary 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/2016/DataSummary/figs/peakMuByFill.png
pdf file

Luminosity summary plots for 2015 pp data taking

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

Total Integrated Luminosity and Data Quality in 2015
Cumulative luminosity versus time delivered to ATLAS (green), recorded by ATLAS (yellow), and certified to be good quality data (blue) during stable beams for pp collisions at 13 TeV centre-of-mass energy in 2015. The delivered luminosity accounts for the luminosity delivered from the start of stable beams until the LHC requests ATLAS to put the detector in a safe standby mode to allow 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. The data quality assessment shown corresponds to the All Good efficiency shown in the 2015 EOYE Dataset DQ table here. The All Good Data Quality criteria require all reconstructed physics objects to be of good data quality. The IBL was turned off for two runs, corresponding to 0.2 fb-1 and analyses that don’t rely on the IBL can use 3.4 fb-1 of data with a corresponding DQ efficiency of 93.1%. The luminosity shown represents the preliminary 13 TeV luminosity calibration which was updated in December 2015.

The table corresponds to the DQ tag DetStatus-v73-pro19-08 with lumi tag OflLumi-13TeV-003.

https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/intlumivstime2015DQ.png
pdf file
For animations: delivered (png) delivered (pdf) recorded (png) recorded (pdf)
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 which was updated in December 2015.
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 preliminary 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
Run-to-run Stability
Run-to-run stability of ATLAS luminometers for the 2015 proton-proton dataset at sqrt(s)=13 TeV, excluding dedicated low luminosity data taking periods. The calorimeter (Tile, FCal, EMEC) and track counting algorithms are cross-calibrated to a LUCID measurement of the integrated luminosity in the reference fill indicated by the arrow. Each point shows the mean fractional difference in integrated luminosity for a single ATLAS run, between the indicated algorithm and the reference LUCID luminosity algorithm. The plot demonstrates the relative stability of ATLAS luminometers at the +-2.5% level.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/OfficialPlots_Stability_ATLASStyle_py_PRELIMINARY.png
pdf file
van der Meer Calibration
Visible interaction rate for the LUCID algorithm (lucBiEvtA), that provides the ATLAS luminosity, in one bunch crossing and per unit bunch population, versus nominal beam separation during horizontal scan 1 in the August 2015 luminosity-calibration session. The total rate measured for a single colliding bunch pair at position 891 in the fill pattern is shown as red circles, and the background-subtracted rate as magenta squares. The background is dominated by random counts from the radioactive Bismuth source used for phototube gain calibration (blue triangles), as estimated from the rate measured in the preceding unfilled bunch slot. Also shown is the beam-gas background (green triangles) measured using non-colliding bunches. The background subtracted rate is fitted by a Gaussian multiplied by a sixth-order polynomial (dashed curve). The error bars are statistical only.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/lucBi_preliminary.png
pdf file

Luminosity summary plots for 2015 5 TeV pp data taking

These plots show the estimated integrated luminosity of the 5 TeV reference data with the online calibration.

Total Integrated Luminosity in 2015
Cumulative luminosity versus time delivered to (green) and recorded by ATLAS (yellow) during stable beams for pp collisions at 5 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. An online calibration based on Monte Carlo estimates has been used to set the luminosity scale.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015hipp/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 5 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/2015hipp/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 5 TeV centre-of-mass energy is shown for each LHC fill as a function of time in 2015. An online calibration based on Monte Carlo estimates has been used to set the luminosity scale.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015hipp/DataSummary/figs/peakLumiByFill.png
pdf file

Luminosity summary plots for 2015 PbPb data taking

These plots show the estimated integrated luminosity of the PbPb collisions at 5 TeV per nucleon. The luminosity shown is the online calibration based on preliminary Monte Carlo estimates.

Total Integrated Luminosity in 2015
Cumulative luminosity versus time delivered to (dark blue) and recorded by ATLAS (light blue) during stable beams for PbPb collisions at 5 TeV centre-of-mass energy per nucleon 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. An online calibration based on Monte Carlo estimates has been used to set the luminosity scale.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015hi/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 PbPb collisions at 5 TeV centre-of-mass energy per nucleon 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/2015hi/DataSummary/figs/lumiByDay.png
pdf file
Peak Luminosity per Fill in 2015
The peak instantaneous luminosity delivered to ATLAS during stable beams for PbPb collisions at 5 TeV centre-of-mass energy per nucleon is shown for each LHC fill as a function of time in 2015. An online calibration based on Monte Carlo estimates has been used to set the luminosity scale.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015hi/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 PbPb collisions at 5 TeV centre-of-mass energy per nucleon is shown for each fill in 2015. The preliminary 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 PbPb cross-section at 5 TeV, which is taken to be 7.7 barns, 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/2015hi/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 - 3 November 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. The luminosity shown represents the preliminary 13 TeV luminosity calibration which was updated in December 2015.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/mu_2015.png
pdf file
eps file
Number of Interactions per Crossing
Same as above, but with data delivered in fills with 50ns and 25ns bunch spacing shown separately.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/mu_2015_2550.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

Pileup Interactions - LHCP dataset

Number of Interactions per Crossing - LHCP Dataset
Shown is the luminosity-weighted distribution of the mean number of interactions per crossing for the 2015 pp collision data recorded from 3 June - 25 August at 13 TeV centre-of-mass energy (LHCP dataset). 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_lhcp.png
pdf file
eps file
Number of Interactions per Crossing - LHCP Dataset
Same as above, but with data delivered in fills with 50ns and 25ns bunch spacing shown separately.
https://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/2015/DataSummary/figs/mu_2015_2550_lhcp.png
pdf file
eps file

Detailed Additional Luminosity related Information


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

Responsible: EricTorrence
Subject: public

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Topic revision: r14 - 2016-05-12 - PaulLaycock
 
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