Gabriele Cosmo
99 lines
3.5 KiB
Plaintext
99 lines
3.5 KiB
Plaintext
$Id: README,v 1.4 2008-09-26 20:26:01 maire Exp $
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-------------------------------------------------------------------
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=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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TestEm18
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--------
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This example allows to study the energy lost by a charged particle in a
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single layer, due to ionization and bremsstrahlung. Results are compared to
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'reference' values.
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1- GEOMETRY DEFINITION
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It is a single box of homogeneous medium.
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Two parameters define the geometry :
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- the material of the box,
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- the (full) size of the box.
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The default geometry (1 cm of water) is constructed in DetectorConstruction,
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but the above parameters can be changed interactively via the commands
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defined in DetectorMessenger.
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2- PHYSICS
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The physics list contains the 'standard' electromagnetic processes.
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However the MultipleScattering is not registered, in order to focuse on
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fluctuations due to energy loss alone.
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3- BEAM
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The primary kinematic is a single particle starting at the edge
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of the box. The type of the particle and its energy are set in
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PrimaryGeneratorAction (e- 10 MeV), and can be changed via the G4
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build-in commands of ParticleGun class.
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4- RUN
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During the tracking of the incident particle, the secondary particles
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are immediately killed, after that their energy has been registered
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(see StackingAction).
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Therefore, we study here the total energy lost by the incident particle,
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not the energy deposited in a layer of finite thickness.
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At EndOfRun, the above results are compared with 'reference' values,
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i.e. the values read from EnergyLoss tables.
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5- HISTOGRAMS
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The test contains 6 built-in 1D histograms, which are managed by
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G4AnalysisManager and its Messenger.
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1 continuous energy loss along primary track
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2 energy from secondaries
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3 total energy lost by primary track (1+2)
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4 energy spectrum of e-+
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5 energy spectrum of gamma
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6 step size of primary track
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The histograms are defined in HistoManager.
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The histos can be activated individually 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, cm or mm, 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 testem18)
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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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It is also possible to print selected histograms on an ascii file:
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/analysis/h1/setAscii id
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All selected histos will be written on a file name.ascii (default testem18)
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6- VISUALIZATION
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The Visualization Manager is set in the main().
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The initialisation of the drawing is done via the commands
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/vis/... in the macro vis.mac. To get visualisation:
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> /control/execute vis.mac
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The detector has a default view which is a longitudinal view of the box.
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The tracks are drawn at the end of event, and erased at the end of run.
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7- HOW TO START ?
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execute TestEm18 in 'batch' mode from macro files :
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% TestEm18 electron.mac
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execute TestEm18 in 'interactive mode' with visualization :
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% TestEm18
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Idle> control/execute vis.mac
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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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