Gabriele Cosmo
117 lines
4.2 KiB
Plaintext
117 lines
4.2 KiB
Plaintext
=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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FissionFragment Example
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B.Wendt
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brycen.linn.wendt@cern.ch
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This example demonstrates an application of the fission fragment model in the
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NeutronHP model. This example is capable of using both models, but is designed
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around the Wendt Fission Model. A warning will be shown if the environment
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variable that enables the Wendt fission model is not set.
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1 - EXECUTION
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A - ENVIRONMENT
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G4NEUTRONHP_PRODUCE_FISSION_FRAGMENTS - REQUIRED
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The example requires this enviroment variable to be set. An error will be
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displayed and the example will terminate if this environment variable is
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not set.
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G4NEUTRON_HP_USE_WENDT_FISSION_MODEL - OPTIONAL
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This environment variable enables the Wendt fission model contained
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within the NeutronHP model for simulating fission events. The default model
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will be used otherwise. A warning will be displayed if this environment
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variable is not set.
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B - COMMAND LINE ARGUMENTS
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The example can be run without any input arguments. However, a few options
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are available:
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-i ARG : run in batch mode from script file ARG
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-o ARG : write output to file ARG
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(defaults to FF_Neutron_HP.out)
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-n ARG : multithreading with ARG number of threads
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(only works if Geant4 was compiled with multithreading
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enabled)
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No output is currently generated, although the argument is provided. It is
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anticipated that future versions will provide some form of output
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summarizing the results of the simulation.
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C - INTERACTIVE
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No specialized UI commands are currently provided.
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To run the simulation, use the standard UI command:
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/run/beamOn
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2 - GEOMETRY
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The geometry is constructed in the FFDetectorConstruction class. The setup is
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based on a subcritical assembly design.
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A - MATERIALS
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This example requires a number of materials. They are loaded or constructed
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in the "DefineMaterials" function. A few of the materials are obtained from
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the NIST database (ref. Geant4 User's Guide for Application Developers,
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Appendix: Geant4 Materials Database). These materials are:
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- Air
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- Aluminum
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- Graphite
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- Polyethylene
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- Stainless steel
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- Water
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Not all of the necessary materials were available from the NIST database,
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and were constructed manually from the estimated isotopics. These materials
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are:
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- 20% U235 enriched uranium
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- 93% B10 enriched BF3
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B - Volumes
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The world is composed of air instead of a vacuum to provide room return.
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The subcritical assembly is a water-filled aluminum tank.
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The fuel plates are composed of aluminum-clad uranium meat, and are
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completely submersed in the water of the subcritical assembly.
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An AmBe neutron source is placed in the exact center of the fuel plate
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loading configuration. The material is currently modeled as steel until
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more exact specifics of the AmBe isotopics can be obtained.
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The subcritical assembly rests on top of a graphite pile for moderation and
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shielding.
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3 - PHYSICS LIST
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The particle's type and the physic processes which will be available
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in this example are set in the QGSP_BIC_HP physics list.
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4 - PRIMARY GENERATOR
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The primary generator is defined in the FFPrimaryGeneratorAction class.
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The default particle is a 4.5 MeV neutron originating from the
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"NeutronSource" volume. The particles initial direction is isotropically
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sampled.
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5 - DETECTOR RESPONSE
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The scoring method is yet to be implemented, although the BF3 detector is
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already included in the detector construction.
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6 - VISUALISATION
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An example "vis.mac" will be included in a future release. For now, please
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refer to other examples for a few suggestions.
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