Gabriele Cosmo
115 lines
3.3 KiB
Plaintext
115 lines
3.3 KiB
Plaintext
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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HADR00
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V.Ivanchenko
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CERN, Geneva, Switzerland
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This example demonstrates a usage of G4PhysListFactory to build
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Physics List and G4HadronicProcessStore to access cross sections.
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GEOMETRY
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The Target volume is a cilinder placed inside the World volume. Follwoing
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UI commands are available to modify the geometry:
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/testhadr/TargetMat G4_Pb
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/testhadr/WorldMat G4_AIR
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/testhadr/TargetRadius 10 mm
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/testhadr/TargetLength 20 cm
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If geometry was changed between two runs, then the follwoing command need to
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be executed:
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/testhadr/update
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By default beam direction coinsides with the target axis and is Z axis
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in the global coordinate system. The beam starts in the middle of the target.
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G4ParticleGun is used as a primary generator. The energy and the type of
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the beam can be defined via standard UI commands
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/gun/energy 15 GeV
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/gun/particle proton
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PHYSICS
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Physics List is defined by the PHYSLIST environment variable. By default
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QGSP_BERT Physics List will be instantiated.
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CROSS SECTION
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At the end of any run the set of cross sections is built and can be printed
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out for a given progectile particle and a target element, which can be
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defined via UI commands:
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/testhadr/particle pi+
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/testhadr/targetElm Pb
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/testhadr/verbose 1
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The level verbosity above zero provides printout of the cross section table.
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The energy/momentum limits and number of bins can be set via UI commands:
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/testhadr/nBinsE 900
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/testhadr/nBinsP 700
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/testhadr/minEnergy 1 keV
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/testhadr/maxEnergy 1 TeV
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/testhadr/minMomentum 1 MeV
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/testhadr/maxMOmentum 10 TeV
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VISUALISATION
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For interactive mode G4 visualization options and variables should be
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defined, then the example should be recompiled:
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gmake visclean
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gmake
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The vis.mac file can be used an example of visualization. The following
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command can be used:
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/testhadr/DrawTracks charged
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/testhadr/DrawTracks neutral
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/testhadr/DrawTracks all
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HISTOGRAMS
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All histograms are provided in decimal logarithmic scale (log10(E/MeV)
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and log10(p/GeV)) for one projectile particle and one target element.
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The element is taken from the Geant4 NIST datebase, natural isotope
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composition is assumed.
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To use histograms any of implementations of AIDA interfaces should
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be available (see http://aida.freehep.org).
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For example, if iAIDA is installed and compiled at SLC4 Linux
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setenv AIDA_DIR $MYPACKAGES/analysis/iAIDA/install/slc4_amd64_gcc34_root
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setenv PATH ${PATH}:${AIDA_DIR}/bin
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Before compilation of the example it is optimal to clean up old
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object files:
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gmake histclean
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setenv G4ANALYSIS_USE 1
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gmake
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It is possible to choose the format of the output file with
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histograms using UI command:
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/testhadr/HistoName name
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/testhadr/HistoType type
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/testhadr/HistoOption "uncompress"
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The following types are available: hbook, root, aida. They will be
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stored in the file "name.hbook", "name.root", or "name.aida".
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To show the contence of a histogram ID=i the commands may be applied:
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/testhadr/HistoPrint i
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