Gabriele Cosmo
93 lines
2.9 KiB
Plaintext
93 lines
2.9 KiB
Plaintext
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Extended Example for G4GeneralParticleSource (GPS)
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--------------------------------------------------
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exgps is created to demonstrate the usage of G4GeneralParticleSource
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for generating primary particle according to user defined distributions.
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These range from simple monocromatic point source to complicated mutiple
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sources with various biasing schemes.
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http://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides
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/ForApplicationDeveloper/html/ch02s07.html
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1 - GEOMETRY
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Simple geometry consists of a "Vacuum" world and, in it, two other components:
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- An alunimium box : 20 x 20 x 20 cm in size, cerntered at the origin.
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- A SiO2 sphere (radius 5 cm) is placed at the centre of the aluminium box.
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2 - PHYSICS
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Tranportation process only for all particles.
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3 - EVENT
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The event generator is the G4GeneralParticleSource (GPS). The instantiation of
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G4GeneralParticleSource is same as that for G4ParticleGun.
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See the exGPSPrimaryGeneratorAction.cc file for details.
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4 - VISUALIZATION
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Visualisation of the geometry and the tracks is possible with many of the
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G4 visualisation packages.
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An example of displaying the geometry and tracks using OGL is given in the
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macro vis.mac.
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5 - HISTOGRAMS
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This example implements an histo manager which creates histograms and
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ntuples using Geant4 analysis tools.
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The output file contains 6 histograms and one ntuple:
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histo1D 1: energy spectrum.
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histo1D 2: vertex: radial distribution dN/dv.
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histo1D 3: angular distribution: cos(theta).
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histo1D 4: angular distribution: phi.
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histo2D 1: vertex position in the X-Y plane.
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histo2D 2: vertex position in the X-Z plane.
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histo2D 3: vertex position in the Y-Z plane.
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histo2D 4: angular distribution: phi-cos(theta).
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histo2D 5: angular distribution: of phi-theta.
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In the ntuple the following data are recorded for each incident particle:
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Particle ID
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Incident Position (x,y,z);
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Incident Angle (theta,phi);
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Particle weight;
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The histograms are managed by G4AnalysisManager class and its Messenger.
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The histos can be individually activated with the command :
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/analysis/h1/set id nbBins valMin valMax unit
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where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
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One can control the name of the histograms file with the command:
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/analysis/setFileName name (default exgps)
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It is possible to choose the format of the histogram file : root (default),
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xml, csv, by using namespace in HistoManager.hh
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6 - GETTING STARTED
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- execute exgps in 'batch' mode from macro files
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% exgps exgps.in
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- execute exgps in 'interactive mode' with visualization
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% exgps
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....
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Idle> type your commands
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....
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Idle> exit
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7 - FURTHER EXAMPLES of MACRO FILES
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There are a number of mac files in the ./macros subdirectory, to show the
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various features of GPS.
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Please see README file there for further informations.
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