Gabriele Cosmo
166 lines
6.3 KiB
Plaintext
166 lines
6.3 KiB
Plaintext
$Id: README,v 1.7 2002/12/12 13:26:50 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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TestEm5
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-------
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1- GEOMETRY DEFINITION
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The "absorber" is a box made of a given material.
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Three parameters define the absorber :
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- the material of the absorber,
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- the thickness of an absorber,
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- the transverse size of the absorber (the input face is a square).
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The volume "World" contains the "absorber".
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In this test the parameters of the "World" can be changed, too.
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In addition a transverse uniform magnetic field can be applied.
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The default geometry is constructed in DetectorConstruction class,
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but all the parameters can be changed via
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the commands defined in the DetectorMessenger class.
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2- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle which hits the
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absorber perpendicular to the input face. The type of the particle
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and its energy are set in the PrimaryGeneratorAction class, and can
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be changed via the G4 build-in commands of ParticleGun class (see
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the macros provided with this example).
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In addition one can choose randomly the impact point of the incident
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particle. The corresponding interactive command is built in
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PrimaryGeneratorMessenger class.
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A RUN is a set of events.
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3- DETECTOR RESPONSE
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A HIT is a record, event per event , of all the
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informations needed to simulate and analyse the detector response.
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In this example a CalorHit is defined as a set of 2 informations:
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- the total energy deposit in the absorber,
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- the total tracklength of all charged particles in the absorber,
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Therefore the absorber is declared
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'sensitive detector' (SD), which means they can contribute to the hit.
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At the end of a run, from the histogram(s), one can study
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different physics quantities such as :
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- angle distribution,
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- energy deposit,
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- transmission/backscattering,
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- ...
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The test contains 10 built-in histograms, which can be activated by
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interactive commands (see the macros runxx.mac for details).
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The histograms/plots are in printed form in the corresponding
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resultxx (for GEANT4) and outxx (for GEANT3) files, and they are
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saved as geant4.plotxx and geant3.plotxx histogram files, too.
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The histogram files can be viewed using PAW e.g with the commands
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paw> h/file 1 geant4.plot01
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paw> option stat
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paw> h/pl 1
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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. In interactive session:
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PreInit or Idle > /control/execute vis.mac
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The detector has a default view which is a longitudinal view of the
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calorimeter.
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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 DEMO
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The particle's type and the physic processes which will be available
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in this example are set in PhysicsList class.
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The messenger classes introduce interactive commands . Using these
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commands the geometry of the detector, the data of the primary
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particle, the limits of the histograms , etc. can be changed.
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6- HOW TO START ?
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- compile and link to generate an executable
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% cd TestEm5
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% gmake
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- execute TestEm5 in 'batch' mode from macro files e.g.
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% $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm5 run01.mac
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- execute TestEm5 in 'interactive' mode with visualization e.g.
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% $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm5
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....
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Idle> type your commands
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....
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7- GEANT4/GEANT3/exp.data comparison
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A GEANT4/GEANT3/exp. data comparison is given here for a few cases.
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The GEANT4 results can be found in the results/ directory, the resultxx
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output was obtained with the runxx.mac macro.
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The relevant part of the GEANT3 code is in the geant3/ directory
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together with the runxx.dat input files. The outputs of the GEANT3 runs
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geant3/results subdirectory.
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In order to make an executable of GEANT3 the gmakeB command should be
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used in the geant3/ subdirectory.To run this executable with a given
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input file the input file name should be given when it is being asked
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by the program.(see geant3/README)
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The expdata/ directory contains some information
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on the experimental data.
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List of the built-in histograms
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-------------------------------
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1. number of (tracking) steps/event
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2. energy deposit distribution in the absorber (in MeV)
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3. angle distribution of the primary particle at the exit
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of the absorber (deg)
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4. distribution of the lateral displacement at exit(mm)
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5. kinetic energy of the transmitted primaries (MeV)
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6. angle distribution of the backscattered primaries (deg)
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7. kinetic energy of the backscattered primary particles (MeV)
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8. kinetic energy of the charged secondary particles (MeV)
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9. z distribution of the secondary charged vertices (mm)
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10. kinetic energy of the photons escaping the absorber (MeV)
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Note that histograms are disabled via the flag G4NOHIST in GNUmakefile.
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8- Using the Anaphe implementation of the AIDA 3.0 histograms:
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--------------------------------------------------------------
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In order to use the Anaphe implementation of the AIDA 3.0 interfaces,
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the 'aida-config' command (which is used in the GNUmakefile) is
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available at:
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/afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/aida-config
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In order to run the executable, you need to source the following
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script (once):
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$HOME/bin/setupAnaphe.csh (or $HOME/bin/setupAnaphe)
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At cern 'setupAnaphe' is available at:
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/afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/setupAnaphe.csh
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(or /afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/setupAnaphe)
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