This form provides a restricted interface to the luminosity calculator iLumiCalc.exe. A Good Run List appropriate for your processed data sample is required as an input.

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LumiCalc News

If your request seems to hang and you eventually see a Proxy Error after clicking Calculate Luminosity, this is annoying but not fatal. Just reload the page and your job should be running fine.

Recommendations

Data SampleRecommended
Luminosity Tag
Recommended
Livefraction Trigger
Comments
data18_hiOflLumi-HI-009
(OflLumi-HI-007 or later)
L1_EM12Preliminary 2018 calibration
data18_900GeVOflLumi-900GeV-002L1_ALFA_ELAST15Preliminary 2018 calibration
data18_13TeVOflLumi-13TeV-010L1_EM24VHIPreliminary 2018 calibration
2017/18 13TeV low-muOflLumi-13TeV-010-lowmuL1_EM24VHIPreliminary 2017/18 low-mu data calibration
data17_5TeVOflLumi-5TeV-003L1_EM24VHIPreliminary 2017 5 TeV calibration
data17_13TeVOflLumi-13TeV-010L1_EM24VHIPreliminary 2017 calibration
data16_13TeVOflLumi-13TeV-010
(OflLumi-13TeV-009 or later)
L1_EM12Final 2016 calibration
data16_hip8TeVOflLumi-HI-009
(OflLumi-HI-006 or later)
L1_EM12Updated calibrations (Winter 2019)
data16_hip5TeVOflLumi-HI-009
(OflLumi-HI-004 or later)
L1_EM12Online calibration
data15_13TeVOflLumi-13TeV-010
(OflLumi-13TeV-004 or later)
L1_EM12Final 2015 vdM calibration
data15_hiOflLumi-HI-009L1_EM12Final 2015 vdM estimate
data15_5TeVOflLumi-5TeV-003L1_EM12Final vdM calibration
data13_hipOflLumi-HI-003L1_LUCID_A_CFinal vdM calibration
data13_2p76TeVOflLumi-2p76TeV-002L1_LUCID_A_CFinal 2.76 lumi
data12_8TeVOflLumi-8TeV-004L1_EM30Final 2012 vdM calibration
data11_7TeVOflLumi-7TeV-004L1_EM30Final 2011 results
(with beam-beam corrections)
data10_7TeVOflLumi-7TeV-004L1_MBTS_2Final 2010 results
(with beam-beam corrections)
data11_2p76OflLumi-2p76TeV-002L1_LUCID_A_CFinal 2.76 lumi
data10_hiOflLumi-HI-000L1_LUCID_A_COnline estimate

Luminosity Calculator

See below for a synopsis of these quantities.

GRL XML File: GRL XML file which defines the data sample of interest. See below for information how to specify a subset of a GRL.
Luminosity Tag: Tag which defines the specific version of the luminosity measurement. Only use --online for diagnostic checks.
Live Fraction Trigger: This trigger is only used to compute the L1 live fraction. Any high rate L1 trigger can be used. Please see below for recommendations.
Physics Trigger: This trigger is used to compute the prescale correction. It is possible to use a L1 trigger, but if that trigger is prescaled at the HLT, you will get the wrong result! Specify None to assume a prescale of 1 for all luminosity blocks.
LAr EventVeto Tag: Tag which defines the LAr Event Veto information. Must be used to assess LAr Event Veto inefficiency. Use None to turn this off. See below or here for details.
Other Options: Calculate BGRP7 luminosity (--lumichannel=17)
Require online beamspot (--beamspot)
Create output plots and ntuples (--plots)
Verbose output (--verbose)
Additional options
Add any additional options here. Use --help, or just click the Calculate Luminosity button below with no GRL specified, to find other possibilities.

Remember, this process can take considerable time (minutes) for large data samples. Pushing the button again will only make things worse. Please be patient!

Definitions

Good Run List

A Good Run List (GRL) is an ATLAS standard XML file format which defines a list of Run and Luminosity Blocks to be considered. The only officially supported source of GRLs is through the Good Runs List Generator. There is also a growing list of pre-computed standard GRLs available.

To specify a subset of an entire GRL, you can use the the run specifier in the Other Options box. For example, -r 180614-180776,182726-183462 will only process runs in the XML file found in that run range. This happens to correspond to periods E and G. You can use a single run, a range, an open-ended range (e.g.: -r 182726-), or combine any of these into a comma separated list. A run which satisfies any of these run-range criteria will be processed.

Luminosity Tag

The luminosity tag specifies the tag of the offline luminosity folder in COOL to use. Details on the available tags can be found at the Offline Luminosity Tags TWiki page.

Live Fraction Trigger

Technically a question of trigger efficiency, for convenience the luminosity calculator also will compute the L1 live fraction, which is the fraction of delivered luminosity which ATLAS actually recorded. Triggered events can be ignored (vetoed) for a number of reasons, including DAQ deadtime, HLT or SFO backpressure, or because the DAQ is paused. Currently, the method for measuring the L1 live fraction is to count the number of triggers before and after veto which is stored independently in COOL. In typical operations, all triggers in a given bunch group should observe an identical veto rate (and hence share the same live fraction). The best trigger to use to make this determination is a trigger which has a high rate after prescale, so that the statistical uncertainty per luminosity block is low.

The recommended live fraction triggers are:

One can also check the livefraction using any L1 physics trigger and similar results should be obtained. Problems can be found if the prescaled trigger has a low enough rate to be in the range of Poisson statistics per lumi block, although summed over many luminosity blocks, the overall livefraction rate should still be accurate.

Physics Trigger

As another convenience, the luminosity calculator can also incorporate any trigger prescale into the definition of luminosity, but similar to the live fraction this is really a measure of the trigger efficiency. It is important to always specify the ultimate EF trigger, as the relevant prescale factor is the product of L1, L2, and EF prescales. Even though a given L1 trigger may be unprescaled, it doesn't mean that the HLT hasn't been configured to throw events away. The luminosity calculation divides the delivered luminosity per lumi block by the total prescale factor to arrive at the luminosity after prescale. The column reporting Lumi-weighted prescale is simply the ratio of total luminosity with and without this correction. If you prefer to deal with the prescales somewhere else in your analysis, simply specify None and a prescale of 1 will be assumed.

If the specified trigger item doesn't exist or is disabled for a given luminosity block (indicated in TrigConf by a prescale of -1), the luminosity calculator will treat this as an infinite prescale. This means this lumi block will not contribute to the delivered luminosity after prescale. In addition, this luminosity block will be marked as 'Bad' in the accounting of Good/Bad luminosity blocks. The other reason why a lumi block will be flagged as bad is if the luminosity value is known to be invalid. No lumi block with a Green LUMI DQ flag should contain invalid data.

Please note that the random trigger rates are not currently accounted for by the luminosity calculator. Any random-seeded trigger will typically have a luminosity reported which is much larger than the true luminosity.

LAr Event Veto

Starting with the Release 17 reprocessing (Summer 2011) and all data taken from September 2011 onwards, certain LAr defects (noise bursts) are not rejected at the GRL stage. Users must reject specific events instead, as more fully described on the LArEventVetoRel17 TWiki. The loss of luminosity from applying these event vetos is calculated by determining what fraction of a given luminosity block has fallen into one of these LAr EventVeto periods. The LAr event veto database is versioned, and one must use the DB tag which matches the version of the data being processed. Please consult the LArEventVetoRel17 TWiki for the latest recommendation. For 2017, the data reconstructed at the Tier0 (t0pro21_v01 containers) needs LARBadChannelsOflEventVeto-RUN2-UPD4-06, while the reprocessed data will use LARBadChannelsOflEventVeto-RUN2-UPD4-08. Either tag is fine for Run2 data before 2017. As of 2018, LARBadChannelsOflEventVeto-RUN2-UPD4-10 contains the best information for all running periods.

If you want to specify a tag not present in the pop-up list, specify none, and in the Other Options box use --lar --lartag=TAG.

Other Options

Additional options can be specified in the text box, or by using the handy check boxes for commonly used options. For triggers which use BGRP7, you must specify channel 17 to get the BGRP7 luminosity. For triggers which include b-jet triggers, you must require the online beamspot status to be valid to get the correct livefraction.