Gabriele Cosmo
148 lines
5.3 KiB
Plaintext
148 lines
5.3 KiB
Plaintext
//$Id$
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///\file "electromagnetic/TestEm1/.README"
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///\brief Example TestEm1 README page
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/*! \page ExampleTestEm1 Example TestEm1
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- How to count processes.
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- How to activate/inactivate processes.
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- How to survey the tracking, in perticular the range of charged particles.
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- How to define a maximum step size.
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\section TestEm1_s1 GEOMETRY DEFINITION
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It is a simple box which represente an 'semi infinite' 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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In addition a transverse uniform magnetic field can be applied.
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The default geometry is constructed in DetectorConstruction class, but all of
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the above parameters can be changed interactively via the commands defined in
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the DetectorMessenger class.
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\section TestEm1_s2 PHYSICS LIST
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Physics lists can be local (eg. in this example) or from G4 kernel
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physics_lists subdirectory.
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Local physics list:
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- "local" standard EM physics with current 'best' options setting.
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these options are explicited in PhysListEmStandard
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From geant4/source/physics_lists/builders:
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- "emstandard_opt0" recommended standard EM physics for LHC
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- "emstandard_opt1" best CPU performance standard physics for LHC
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- "emstandard_opt2"
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- "emstandard_opt3" best current advanced EM options.
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analog to "local" above
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Physics lists and options can be (re)set with UI commands
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Please, notice that options set through G4EmProcessOPtions are global, eg
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for all particle types. In G4 builders (geant4/source/physics_lists/builders)
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it is shown how to set options per particle type.
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Few commands have been added to PhysicsList, in order to set the production
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threshold for secondaries for gamma and e-/e+.
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PhysicsList contains also G4Decay and G4RadioactiveDecay processes
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\section TestEm1_s3 AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle starting at the left face
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of the box. The type of the particle and its energy are set in the
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PrimaryGeneratorAction class, and can be changed via the G4 build-in commands
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of G4ParticleGun 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 corresponding interactive command is built in PrimaryGeneratorMessenger.
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\section TestEm1_s4 VISUALIZATION
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The Visualization Manager is set in the main () (see TestEm1.cc).
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The initialisation of the drawing is done via the commands /vis/... in the
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macro vis.mac. To get visualisation:
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\verbatim
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> /control/execute vis.mac
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\endverbatim
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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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\section TestEm1_s5 PHYSICS SURVEY
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The particle's type and the physic processes which will be available in this
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example are set in PhysicsList class.
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A set of macros defining various run conditions are provided. The processes
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are actived/inactived together with differents cuts, in order to survey the
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processes one by one.
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The number of produced secondaries are counted, the number of steps, and the
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number of process calls responsible of the step.
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\section TestEm1_s6 HOW TO START ?
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- Execute TestEm1 in 'batch' mode from macro files
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\verbatim
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% TestEm1 runs.mac
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\endverbatim
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- Execute TestEm1 in 'interactive mode' with visualization
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\verbatim
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% TestEm1
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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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\endverbatim
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\section TestEm1_s7 TRACKING : StepMax
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In order to control the accuracy of the deposition, the user can limit
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'by hand' the maximum step size of charged particles.
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As an example, this limitation is implemented as a 'full' process :
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see StepMax class and its Messenger. The 'StepMax process' is registered
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in the Physics List.
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\section TestEm1_s8 HISTOGRAMS
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Testem1 produces several histo which are saved as testem1.root by default.
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Content of these histo:
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- 1 : track length of primary particle
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- 2 : number of steps primary particle
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- 3 : step size of primary particle
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- 4 : total energy deposit
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- 5 : energy of charged secondaries at creation
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- 6 : energy of neutral secondaries at creation
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The histograms are managed by G4AnalysisManager class and its Messenger.
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The histos can be individually activated with the command :
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/analysis/h1/set 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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One can control the name of the histograms file with the command:
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\verbatim
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/analysis/setFileName name (default testem1)
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\endverbatim
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It is possible to choose the format of the histogram file : root (default),
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hbook, xml, csv, by using namespace in HistoManager.hh
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It is also possible to print selected histograms on an ascii file:
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/analysis/h1/setAscii id
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All selected histos will be written on a file name.ascii (default testem1)
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\subsection TestEm1_subs1 Using hbook format
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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 HistoManager.hh
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*/
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