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