Fast Simulation: How to tune HCAL noise

We tune the HCAL noise and thresholds by matching the energy at RecHit level with FullSim using a simulated sample of single neutrinos of fixed energy.

The content of this page has been tested in CMSSW_5_2_0.

What to tune

HCAL noise (divided by subdetector: HB, HE, HO, HF) is taken from database (same as FullSim).
Further correction factors are applied in FastSim to absorb several differences with respect to FullSim, including those arising at digi/reco level (there is no real digitizer in FastSim, as of CMSSW_5_2_X.)

The file FastSimulation/CaloRecHitsProducer/python/CaloRecHits_cff.py contains the parameters NoiseCorrectionFactor and Threshold for each calorimeter type in CMS.

Practical recipe to tune at RecHit level

  • Neutrino gun in FullSim: Validation/CaloTowers/test/runNoise_NZS_cfg.py
  • Neutrino gun in FastSim: FastSimulation/Calorimetry/test/neutrinogun_fastsim_cfg.py
  • Comparison macro: FastSimulation/Calorimetry/test/noise_plots.C

Validating with standard events at jets level

Same recipe as in FastSimTuningHCALSignal

In principle you expect to see an effect only for very low-pt jets.

-- AndreaGiammanco - 08-Mar-2012

Edit | Attach | Watch | Print version | History: r2 < r1 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r2 - 2012-03-20 - AndreaGiammanco
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    CMSPublic All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback