Gabriele Cosmo
124 lines
3.7 KiB
Markdown
124 lines
3.7 KiB
Markdown
\page ExampleOpNovice Example OpNovice
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This example presently illustrates the following basic concepts, and in
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particular (indicated with ***), how to use G4 for optical photon
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generation and transport. Other extended example of what is possible
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in Geant4 with optical photons can be found at
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examples/extended/optical/LXe and wls
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## main()
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Define Random Number generator initial seed in main().
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## G4OpticalPhysics
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The G4OpticalPhysics physics class is used. The messenger is the
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G4OpticalParametersMessenger class.
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- Define particles; including - *** G4OpticalPhoton ***
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- Define processes; including
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- *** G4Cerenkov ***
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- *** G4Scintillation ***
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- *** G4OpAbsorption ***
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- *** G4OpRayleigh ***
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- *** G4OpBoundaryProcess ***
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A messenger command allows to define interactively the
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verbose level and the maximum number of Cerenkov photons per step
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(see for instance OpNovice.in)
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## G4VUserDetectorConstruction
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- Define material: Air and Water
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- Define simple G4box geometry
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- *** add G4MaterialPropertiesTable to G4Material ***
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- *** define G4LogicalSurface(s) ***
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- *** define G4OpticalSurface ***
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- *** add G4MaterialPropertiesTable to G4OpticalSurface ***
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alternatively the Configuration can be read from a gdml file.
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The provided gdml file NoviceExample.gdml corresponds to the detector
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defined in OpNoviceDetectorConstruction.
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- See class OpNoviceDetectorConstruction
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## G4VUserPrimaryGeneratorAction
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Use G4ParticleGun to shoot a charge particle into a Cerenkov radiator
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A messenger command allows to define interactively the polarization of an
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primary optical photon (see for instance optPhoton.mac)
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- See class OpNovicePrimaryGeneratorAction
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## G4UserRunAction and G4Run
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- Used to accumulate statistics.
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- See classes OpNoviceRunAction and OpNoviceRun
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## G4UserStackingAction and G4UserEventAction
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Show how to count the number of secondary particles in an event
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- See classes OpNoviceStackingAction and OpNoviceEventAction
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## Visualisation
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The Visualization Manager is set in the main().
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The initialisation of the drawing is done via a set of /vis/ commands
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in the macro vis.mac. This macro is automatically read from
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the main in case of interactive running mode.
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The detector has a default view which is a longitudinal view of the tank.
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The tracks are drawn at the end of event, and erased at the end of run.
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## How to start
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- Compile and link to generate an executable
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This example handles the program arguments in a new way.
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It can be run with the following optional arguments:
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```
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$ ./OpNovice [-g gdmlfile] [-m macro ] [-u UIsession] [-t nThreads]
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```
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The -t option is available only in multi-threading mode
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and it allows the user to override the Geant4 default number of
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threads. The number of threads can be also set via G4FORCENUMBEROFTHREADS
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environment variable which has the top priority.
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- Execute OpNovice in 'batch' mode from macro files
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```
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$ ./OpNovice -m OpNovice.in
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```
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- Execute OpNovice in 'batch' mode from macro files using a gdml file
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to define the geometry
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$ OpNovice -g NoviceExample.gdml -m OpNovice.in
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- Execute OpNovice in 'interactive mode' with visualization
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```
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$ ./OpNovice
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....
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Idle> type your commands. For instance:
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Idle> /control/execute optPhoton.mac
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....
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Idle> exit
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```
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Macros
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------
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The following macros are provided:
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- optPhoton.mac: Shoot optical photons with energy 3 eV
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- OpNovice.in: Shoot positrons with energy 500 keV.
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- gui.mac: Configure the graphical user interface.
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- vis.mac: Configure visualization.
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gdml files
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----------
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NoviceExample.gdml: example gdml file corresponding to
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OpNoviceDetectorConstruction
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