Gabriele Cosmo
173 lines
5.4 KiB
Plaintext
173 lines
5.4 KiB
Plaintext
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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HADR01
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A.Bagulya, I.Gudowska, V.Ivanchenko, N.Starkov
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CERN, Geneva, Switzerland
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Karolinska Institute & Hospital, Stockholm, Sweden
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Lebedev Physical Institute, Moscow, Russia
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This example application is based on the application IION developed for
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simulation of proton or ion beam interaction with a water target. Different
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aspects of beam target interaction are demonstrating in the example including
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logitudinal profile of energy deposition, spectra of secondary particles,
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spectra of particles leaving the target. The results are presenting in a form
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of average numbers and histograms.
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GEOMETRY
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The Target volume is a cilinder placed inside Check cilindrical volume. The
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Check volume is placed inside the World volume. The radius and the length of
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the Check volume are 1 mm larger than the radiaus and the length of the Target.
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The material of the Check volume is the same as the World material. The World
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volume has the sizes 10 mm larger than that of the Target volume. Any naterial
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from the Geant4 database can be defined. The default World material is
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G4Galactic and the default Target material is aluminum. The Target is
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subdivided on number of equal slices. Follwoing UI commands are available to
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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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/testhadr/NumberDivZ 200
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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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Beam direction coinsides with the target axis and is Z axis in the global
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coordinate system. The beam starts 5 mm in front of the target. G4ParticleGun
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is used as a primary generator. The energy and the type of the beam can be
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defined via standard UI commands
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/gun/energy 15 GeV
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/gun/particle proton
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Default beam position is -(targetHalfLength + 5*mm) and direction along Z axis.
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Beam position and direction can be changed by gun UI commands:
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/gun/position 1 10 3 mm
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/gun/direction 1 0 0
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however, position command is active only if before it the flag is set
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/testhadr/DefaultBeamPosition false
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SCORING
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The scoring is performed with the help of UserStackingAction class and two
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sensitive detector classes: one associated with a target slice, another with
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the Check volume. Each secondary particle is scored by the StackingAction. In
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the StackingAction it is also possible to kill all or one type of secondary
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particles
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/testhadr/Kill neutron
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/testhadr/KillAllSecondaries
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To control running the following options are available:
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/testhadr/PrintModulo 100
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/testhadr/DebugEvent 977
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The last command selects an events, for which "/tracking/verbose 2" level
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of printout is established.
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PHYSICS
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PhysicsList of the application uses components, which are distributed with
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Geant4 in /geant4/physics_lists subdirectory. So, before compiling hadro01 it
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is necessary to compile physics_lists
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The choice of the physics is provided by the UI command:
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/testhadr/Physics QGSP
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The command
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/testhadr/Physics PHYSLIST
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allows allows to download a physics configuration defined by an environment
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variable PHYSLIST.
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To see the list of available configurations one can use
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/testhadr/ListPhysics
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The cuts for electromagnetic phsyics can be established via
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/testhadr/CutsAll 1 mm
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/testhadr/CutsGamma 0.1 mm
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/testhadr/CutsEl 0.2 mm
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/testhadr/CutsPos 0.3 mm
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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 command can
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be used:
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/testhadr/DrawTracks charged
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/testhadr/DrawTracks charged+n
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/testhadr/DrawTracks neutral
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/testhadr/DrawTracks all
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HISTOGRAMS
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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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A package including AIDA and extended interfaces also using Python
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is PI, available from: http://cern.ch/pi .
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Once installed PI or PI-Lite in a specified local area $PI_DIR, it is
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required to add the installation path to $PATH, i.e. for example,
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for release 1.2.1 of PI:
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setenv PATH ${PATH}:$PI_DIR/1.3.12/app/releases/PI/PI_1_3_12/slc3_gcc323/bin
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CERN users can use the PATH to the LCG area on AFS.
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Before compilation of the example it is optimal to clean up old
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files:
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gmake histclean
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setenv G4ANALYSIS_USE 1
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gmake
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Before running the example the command should be issued:
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eval `aida-config --runtime csh`
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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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If the environment variable HISTODIR is defined, files are stored in this
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subdirectory.
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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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All histograms are normalised to the number of events.
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