Speaker
Norman Anthony Graf
(SLAC National Accelerator Laboratory (US))
Description
slic: Geant4 simulation program
As the complexity and resolution of particle detectors increases,
the need for detailed simulation of the experimental setup also
increases. Designing experiments requires efficient tools to
simulate detector response and optimize the cost-benefit ratio
for design options. We have developed efficient and flexible
tools for detailed physics and detector response simulation which
builds on the power of the Geant4 toolkit but frees the end user
from any C++ coding. The primary goal has been to develop a software
toolkit and computing infrastructure to allow physicists from
universities and labs to quickly and easily contribute to detector
design without requiring either coding expertise or experience with
Geant4.
Geant4 is the de facto high-energy physics standard for simulating
the interaction of particles with fields and materials. However, the
end user is required to write their own C++ program, and the learning
curve for setting up the detector geometry and defining sensitive
elements and readout can be quite daunting. We have developed the
Geant4-based detector simulation program, slic, which employs generic
IO formats as well as a textual detector description. Extending the
pure geometric capabilities of GDML, LCDD enables fields, regions,
sensitive detector readout elements, etc. to be fully described at
runtime using an xml file. We also describe how more complex geometries,
such as those from CAD programs, can be seamlessly incorporated into
the xml files. We provide executable programs for Windows,
Mac OSX and Linux, allowing physicists to design detectors within minutes.
We present the architecture as well as the implementation for several
candidate ILC, CLIC and Muon Collider detector designs. We also describe
the implementation of a fixed target experiment (HPS at JLab) and a
proton computed tomography (pCT) implementation, demonstrating
both the flexibility and the power of the system.
org.lcsim: event reconstruction and analysis
Maximizing the physics performance of detectors being designed for the ILC,
while remaining sensitive to cost constraints, requires a powerful, efficient,
and flexible simulation, reconstruction and analysis environment to study
the capabilities of a large number of different detector designs. The
preparation of Letters Of Intent for the ILC involved the detailed study of
dozens of detector options, layouts and readout technologies; the final
physics benchmarking studies required the reconstruction and analysis of
hundreds of millions of events.
We describe the Java-based software toolkit (org.lcsim) which was used for
full event reconstruction and analysis. The components are fully modular
and are available for tasks from digitization of tracking detector signals
through to cluster finding, pattern recognition, track-fitting, calorimeter
clustering, individual particle reconstruction, jet-finding, and analysis.
The detector is defined by the same xml input files used for the detector
response simulation, ensuring the simulation and reconstruction geometries
are always commensurate by construction. We discuss the architecture as
well as the performance.
In addition to the ILC LOI studies, we describe the use of the org.lcsim
software at CERN for CLiC physics and detector studies which culmintaed in
the successful completion of their CDR, its application for dual-readout
crystal calorimeter detector R&D at Fermilab, and detector design and event
reconstruction, including an online trigger, for the proposed “heavy photon”
experiment HPS at JLAB.
Authors
Jeremy McCormick
(Unknown)
Norman Anthony Graf
(SLAC National Accelerator Laboratory (US))
