CaltechAUTHORS
Published July 15, 2008 | Version public
Journal Article Open

Fast shower simulation in the ATLAS calorimeter

Creators

  • 1. ROR icon University of Melbourne
  • 2. ROR icon University of Pittsburgh
  • 3. ROR icon SLAC National Accelerator Laboratory
  • 4. ROR icon University of Toronto
  • 5. ROR icon European Organization for Nuclear Research
  • 6. ROR icon Universität Hamburg
  • 7. ROR icon Deutsches Elektronen-Synchrotron DESY
  • 8. ROR icon California Institute of Technology
  • 9. ROR icon Columbia University
  • 10. ROR icon University of Pavia
  • 11. ROR icon University of Sydney

Abstract

The time to simulate pp collisions in the ATLAS detector is largely dominated by the showering of electromagnetic particles in the heavy parts of the detector, especially the electromagnetic barrel and endcap calorimeters. Two procedures have been developed to accelerate the processing time of electromagnetic particles in these regions: (1) a fast shower parameterisation and (2) a frozen shower library. Both work by generating the response of the calorimeter to electrons and positrons with Geant 4, and then reintroduce the response into the simulation at runtime. In the fast shower parameterisation technique, a parameterisation is tuned to single electrons and used later by simulation. In the frozen shower technique, actual showers from low-energy particles are used in the simulation. Full Geant 4 simulation is used to develop showers down to ~1 GeV, at which point the shower is terminated by substituting a frozen shower. Judicious use of both techniques over the entire electromagnetic portion of the ATLAS calorimeter produces an important improvement of CPU time. We discuss the algorithms and their performance in this paper.

Additional Information

Accepted papers received: 23 June 2008. Published online: 31 July 2008. © 2008 IOP Publishing Ltd. International Conference on Computing in High Energy and Nuclear Physics (CHEP '07) Victoria, BC, Canada, 2-7 September 2007.

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Eprint ID
13539
Resolver ID
CaltechAUTHORS:BARjpcs08

Dates

Created
2009-06-17
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Updated
2022-07-12
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