Gabriele Cosmo
101 lines
3.2 KiB
Plaintext
101 lines
3.2 KiB
Plaintext
-------------------------------------------------------------------
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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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TestEm4
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-------
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Plot energy deposited by 9 MeV photon beam in an homogeneous medium.
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1- GEOMETRY DEFINITION
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It is a cylinder of 5 cm radius filled with C6F6.
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2- PHYSICS LIST
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The particle list contains only gamma, electron,positron.
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The physics list contains the 'standard' electromagnetic processes.
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3- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic is a single 9 MeV gamma randomly shooted at the
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middle of the cylinder.
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4- 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. This macro is
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automatically read from the main in case of interactive running mode.
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The detector has a default view which is a transversal view of the
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cylinder.
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The tracks are drawn at the end of event, and erased at the end of run.
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Optionaly one can choose to draw all particles, only the charged one,
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or none. This command is defined in EventActionMessenger class.
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5- PHYSICS SURVEY
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The energy deposited in C6F6 is histogramed.
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6- HOW TO START ?
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- execute TestEm4 in 'batch' mode from macro files
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% TestEm4 TestEm4.in
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- execute TestEm4 in 'interactive mode' with visualization
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% TestEm4
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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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- visualize the histogram (paw)
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paw> h/file 1 testem4.hbook
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paw> option stat
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paw> option logy
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paw> h/pl 1
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7- USING HISTOGRAMS
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The format of the histogram file can be : root (default),
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hbook, xml, csv, by selecting g4nnn.hh in RunAction.hh
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Using hbook format
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------------------
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Need a special treatement : the Cern Library must be installed and the
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environment variable CERNLIB correctly set. Then, *before* compiling,
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activate G4_USE_HBOOK in GNUmakefile and g4hbook.hh in RunAction.hh
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8- RANDOM NUMBERS HANDLING
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CLHEP provides several random number engines. In this example the Ranecu
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engine is choosen at beginning of the main (TestEm4.cc).
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By default, G4RunManager does not save the rndm seed.
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To do so the user must set in BeginOfRunAction:
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G4RunManager::GetRunManager()->SetRandomNumberStore(true);
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Then the rndm seed is systematically saved at beginning of run
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(currentRun.rndm) and beginning of event (currentEvent.rndm)
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Therefore, in case of abnormal end, the seed of the last event processed
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is available in currentEvent.rndm
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Even in case of normal run processing, the user may wish to preserve the
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rndm seed of selected events. At any time in the event, put the
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following statement:
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if (condition) G4RunManager::GetRunManager()->rndmSaveThisEvent();
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currentEvent.rndm will be copied to runXXevntYY.rndm
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(see SteppingAction::UserSteppingAction() )
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To restart a run from a given rndm seed, use the UI command :
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/random/resetEngineFrom fileName
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The macro rndmSeed.mac shows how to save and reset the random number
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seed between runs, from UI commands.
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