Gabriele Cosmo
223 lines
8.6 KiB
Plaintext
223 lines
8.6 KiB
Plaintext
$Id: README,v 1.21 2007/11/28 12:37:56 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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How to study the transmission, absorption and reflexion of particles through
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a single, thin or thick, layer of material.
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In perticular, the effects of the multiple scattering can be ploted.
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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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A volume "World" contains the "absorber".
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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, but all the
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parameters can be changed via commands defined in the DetectorMessenger class.
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The parameters of the "World" can be changed, too.
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2- PHYSICS LIST
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The following EM physics lists are available in this example:
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- "standard" standard EM physics (default)
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- "livermore" low-energy EM physics using Livermore data
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- "penelope" low-energy EM physics implementing Penelope models
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- "standardSS" standard EM physics with single Coulomb scattering
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instead of multiple scattering
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Alternatively, the user may use predefined Geant4 builders:
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- "emstandard" G4EmStandardPhysics builder
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- "emstandard_opt1" G4EmStandardPhysics_option1 builder
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- "emstandard_opt2" G4EmStandardPhysics_option2 builder
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See geant4/source/physics_lists/History for details
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3- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle which hits the absorber
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perpendicular to the input face. The type of the particle and its energy are
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set in the PrimaryGeneratorAction class, and can be changed via the G4 build-in
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commands of ParticleGun class (see the macros provided with this example).
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In addition one can choose randomly the impact point of the incident particle.
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The interactive command is built in PrimaryGeneratorMessenger class.
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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 in vis.mac
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In interactive session:
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PreInit or Idle > /control/execute vis.mac
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The example has a default view which is a longitudinal view of the detector.
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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, or none.
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This command is defined in EventActionMessenger class.
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5- TRACKING
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During the tracking, one can keep or not the secondaries : see StackingAction
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class and its Messenger.
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One can also limit 'by hand' the step lenght of the particle. As an example,
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this limitation is implemented as a 'full' process : see StepMax class and its
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Messenger. The 'StepMax process' is registered in the Physics List.
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6- DETECTOR RESPONSE
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At the end of a run, from the histogram(s), one can study different
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physics quantities such as :
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- energy deposit in the absorber,
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- energy spectrum of secondaries at creation,
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- energy spectrum and angle distribution of particles at exit,
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- transmission and backscattering coefficients,
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- ...
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7- List of the built-in histograms
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----------------------------------
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The test contains more than 20 built-in 1D histograms, which are managed by the
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HistoManager class and its Messenger. The histos can be individually activated
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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, deg or mrad, etc..)
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(see the macros xxxx.mac).
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1 "energy deposit in absorber"
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2 "energy of charged secondaries at creation"
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3 "energy of gammas at creation (log10(Ekin/MeV))"
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4 "x_vertex of charged secondaries (all)"
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5 "x_vertex of charged secondaries (not absorbed)"
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10 "(transmit, charged) : kinetic energy at exit"
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11 "(transmit, charged) : ener fluence: dE(MeV)/dOmega"
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12 "(transmit, charged) : space angle dN/dOmega"
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13 "(transmit, charged) : projected angle at exit"
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14 "(transmit, charged) : projected position at exit"
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15 "(transmit, charged) : radius at exit"
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20 "(transmit, neutral) : kinetic energy at exit"
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21 "(transmit, neutral) : ener fluence: dE(MeV)/dOmega"
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22 "(transmit, neutral) : space angle dN/dOmega"
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23 "(transmit, neutral) : projected angle at exit"
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30 "(reflect , charged) : kinetic energy at exit"
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31 "(reflect , charged) : ener fluence: dE(MeV)/dOmega"
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32 "(reflect , charged) : space angle dN/dOmega"
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33 "(reflect , charged) : projected angle at exit"
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40 "(reflect , neutral) : kinetic energy at exit"
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41 "(reflect , neutral) : ener fluence: dE(MeV)/dOmega"
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42 "(reflect , neutral) : space angle dN/dOmega"
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43 "(reflect , neutral) : projected angle at exit"
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The histograms can be viewed using PAW. See below the note on ANAPHE+AIDA.
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One can control the name of the histograms file with the command:
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/testem/histo/setFileName name (default testem5.hbook)
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It is also possible to print selected histograms on an ascii file:
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/testem/histo/printHisto id
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All selected histos will be written on a file name.ascii (default testem5)
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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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8- GEANT4/GEANT3/DATA COMPARISON
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A Geant4/Geant3/exp. data comparison is given here for a few cases.
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These cases can be classified as follow:
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- e-/e+ incident particles versus protons and others.
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- 3 energy regimes: low: < 1MeV; medium: 1MeV -> few 10MeV; high: > 100MeV
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We indicate here the corresponding macros.
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| low energy | medium energy | high energy
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--------------------------------------------------------
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| acosta.mac | |
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e-+ | berger.mac | hanson.mac |
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| hunger.mac | kulchi.mac |
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| tavola.mac | |
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--------------------------------------------------------
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others| bichsel.mac | vincour.mac | shen1.mac shen2.mac
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| | gottsch.mac | tramu.mac
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--------------------------------------------------------
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The relevant part of the GEANT3 code is in the subdirectory geant3 together
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with the xxxx.dat input files.
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9- 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 myMacro.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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Then type your commands, for instance :
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Idle> control/execute vis.mac
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Idle> run/beamOn 5
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....
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10- USING HISTOGRAMS
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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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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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