Gabriele Cosmo
183 lines
7.2 KiB
Plaintext
183 lines
7.2 KiB
Plaintext
$Id: README,v 1.2 2003/04/09 23:20:58 asaim 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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ExampleN07
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----------
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This example simulates three simplified sandwitch calorimeters.
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The main features demonstrated in this example are :
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1. Utilizing a concrete run class derived from G4Run base class for
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accumulating physics quantities and hits as a run
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2. Changing calorimeter geometries without re-building a world volume
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3. Changing materials used in parameterized volumes
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4. Instantiating more than one sensitive detectors with different
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module names from one concrete sensitive detector class
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5. Defining geometrical regions ans setting production thresholds
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for each region
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1- Utilizing a concrete run class derived from G4Run base class for
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accumulating physics quantities and hits as a run
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G4Run is a class the user can inherit and create his/her own concrete
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class for accumulating information useful to him/her. It has a virtual
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method RecordEvent(const G4Event*), which will be invoked by G4RunManager
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at the end of processing each event. By implemeting this method in the
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user'r concrete run class, he/she can store information associating with
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G4Event class itself and hits collections attached with G4Event. In this
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example, ExN07Run is the class derived from G4Run. In the method
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ExN07Run::RecordEvent(const G4Event*), in addition to counting the
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number of events, all hits collections are accessed to accumulate
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energy depositions, step lengths and number of steps.
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In case the user create his/her own run class, an object of this class
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must be instantiated in the method GenerateRun() of his/her concrete
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class derived from G4UserRunAction base class. The pointer to this run
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object must be returned by this method. In this example, ExN07RunAction
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is the class which instantiating ExN07Run class object. In
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ExN07RunAction::EndOfRunAction(const G4Run*) method, ExN07Run object
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is analized to output the run summary.
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It should be noted that some information about generated secondaries
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are collected in ExN07StackinAction instead of sensitive detector class.
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ExN07StackingAction::ClassifyNewTrack(const G4Track*) method is used
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not for classifying tracks sent to the stack, but for accessing to all
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secondaries generated in an event.
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2- Changing calorimeter geometries without re-building a world volume
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In ExN07DetectorConstruction, all solids, logical and physical volumes
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are constructed only once at the first invocation of Constuct() method.
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Positions and number of slices are changed not by re-constructing another
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objects but by modifying data members of already existing objects as
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it is implemented in ExN07DetectorConstruction::SetNumberOfLayers(G4int)
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for changing the number of parameterized volumes, and also
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ExN07DetectorConstruction::SetSerialGeometry(G4bool) for changing the
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position of placed volumes.
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3- Changing materials used in parameterized volumes
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Materials of absorber and sensitive gap in calorimeters are defined by
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ExN07GapParameterisation::ComputeMaterial(const G4int,G4VPhysicalVolume*),
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as well as positions of each layer to be defined by
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ExN07GapParameterisation::ComputeTransformation(const G4int,
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G4VPhysicalVolume*).
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4- Instantiating more than one sensitive detectors with different
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module names from one concrete sensitive detector class
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ExN07CalorimeterSD is constructed three times with deferent module names
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in ExN07DetectorConstruction::Construct(). In addition, each detector
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create two hits collections of ExN07CalorHit. Thus, in total, six hits
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collections of same type are created for each event. To access to each
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of these collections in ExN07EventAction, both module name and collection
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name are combinedly used.
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5- Defining geometrical regions ans setting production thresholds
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for each region
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Setting production thresholds (so-called production cuts) to individual
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region of a detector geometry is the new feature provided by Geant4 5.1
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release. This feature is also called as "Cuts per region".
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Please note that this new feature is supporsed to be used only by the
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users,
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a) who is simulating most complex geometry such as an LHC detector,
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b) and who has enough experience of simulating EM showers in matter.
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We strongly recommend to compare the simulated results of this new
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feature with the results of the same geometry but having uniform
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production thresholds. Setting completely different cut values for
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individual region may break the coherent and comprehensive accuracy
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of the simulation. Thus such cut values should be carefully optimized
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by the user with comparison with results of uniform cuts.
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In ExN07DetectorConstruction::Construct(), Three objects of G4Region
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class are instantiated and set to the logical volumes of each of three
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calorimeter modules. Also, these individual logical volumes are
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registered as "root logical volume" so that all daghter volumes in
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these logical volumes are also affected by the corresponding regions.
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In ExN07PhysicsList::SetCuts(), in addition to set the default threshold
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values for the world volume, three threshold values are set to three
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calorimeter regions respectively. By setting production thresholds to
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a region, gamma, electron or positron will not be generated as a
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secondary if its range is shorter than the production threshold of that
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particular region. Please note that some EM processes still generate
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such secondary below threshold.
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6- Macro files
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exampleN07.in
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To be used for batch mode. The reference output file is made by this
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macro file.
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sample.mac
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To be used for interactive mode. Issue "/control/execute sample.mac"
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when "Idle>" prompt appears.
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vis.mac
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Setting visualization parameters. This macro file will be called
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automatically when interactive execution starts.
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7- UI commands defined in this example
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Command /N07/setAbsMat
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Guidance :
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Select Material of the Absorber.
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Parameter : choice
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Parameter type : s
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Omittable : False
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Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic
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Command /N07/setGapMat
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Guidance :
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Select Material of the Gap.
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Parameter : choice
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Parameter type : s
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Omittable : False
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Candidates : Aluminium liquidArgon Lead Water Scintillator Air Galactic
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Command /N07/numberOfLayers
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Guidance :
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Set number of layers.
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Range of parameters : nl>0
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Parameter : nl
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Parameter type : i
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Omittable : False
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Command /N07/serialGeometry
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Guidance :
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Select calorimeters to be placed in serial or parallel.
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Parameter : serialize
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Parameter type : b
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Omittable : False
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Command /N07/verbose
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Guidance :
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Set verbosity of each event.
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Range of parameters : vl>=0 && vl<10
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Parameter : vl
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Parameter type : i
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Omittable : True
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Default value : taken from the current value
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