Gabriele Cosmo
153 lines
5.3 KiB
Plaintext
153 lines
5.3 KiB
Plaintext
$Id: README,v 1.1 2007/02/13 17:57:19 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 the
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HistoManager class 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 histos can be activated individually with the command :
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/testem/histo/setHisto 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 and the type of the histograms file with
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the commands:
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/testem/histo/setFileName name (default testem18)
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/testem/histo/setFileType name (default hbook)
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Note that, by default, histograms are disabled. To activate them, uncomment
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the flag G4ANALYSIS_USE in GNUmakefile.
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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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compile and link to generate an executable
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% cd geant4/examples/extended/electromagnetic/TestEm18
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% gmake
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execute TestEm18 in 'batch' mode from macro files :
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% TestEm18 electron.mac.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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8- USING HISTOGRAMS
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By default the histograms are not activated. To activate histograms
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the environment variable G4ANALYSIS_USE should be defined. For instance
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uncomment the flag G4ANALYSIS_USE in GNUmakefile.
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Before compilation of the example it is optimal to clean up old files:
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gmake histclean
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gmake
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To use histograms, at least one of the AIDA implementations should be
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available (see http://aida.freehep.org).
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8a - PI
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A package including AIDA and extended interfaces also using Python is PI,
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available from: http://cern.ch/pi
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Once installed PI or PI-Lite in a specified local area $MYPY, it is required
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to add the installation path to $PATH, i.e. for example, for release 1.2.1 of
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PI:
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setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin
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CERN users can use the PATH to the LCG area on AFS.
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Before running the example the command should be issued:
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eval `aida-config --runtime csh`
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8b - OpenScientist
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OpenScientist is available at http://OpenScientist.lal.in2p3.fr.
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You have to "setup" the OpenScientist AIDA implementation before compiling
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(then with G4ANALYSIS_USE set) and running your Geant4 application.
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On UNIX you setup, with a csh flavoured shell :
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csh> source <<OpenScientist install path>/aida-setup.csh
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or with a sh flavoured shell :
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sh> . <<OpenScientist install path>/aida-setup.sh
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On Windows :
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DOS> call <<OpenScientist install path>/aida-setup.bat
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You can use various file formats for writing (AIDA-XML, hbook, root).
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These formats are readable by the Lab onx interactive program
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or the OpenPAW application. See the web pages.
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With OpenPAW, on a run.hbook file, one can view the histograms
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with something like :
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OS> opaw
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opaw> h/file 1 run.hbook ( or opaw> h/file 1 run.aida or run.root)
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opaw> zone 2 2
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opaw> h/plot 1
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opaw> h/plot 2
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