Speaker
Wolfgang Ehrenfeld
(Univ. of Hamburg/DESY)
Description
The simulation of 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 EM particles in these regions: (1) a fast shower
parameterization and (2) a frozen shower library. Both work by
generating the response of the calorimeter to electrons and positrons
with Geant 4, and then re-importing the response into the simulation
at run-time.
In the fast shower parameterization technique, a parameterization is
tuned to single electrons and used later by simulation. In the frozen
shower technique, actual showers from low-energy particles are imported
into the simulation. Simulation in the presence of frozen showers is
then required to develop the shower 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 talk.
| Submitted on behalf of Collaboration (ex, BaBar, ATLAS) | ATLAS |
|---|
Primary author
Wolfgang Ehrenfeld
(Univ. of Hamburg/DESY)
