Gabriele Cosmo
224 lines
9.8 KiB
Plaintext
224 lines
9.8 KiB
Plaintext
$Id: README 66526 2012-12-19 13:41:33Z ihrivnac $
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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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ExampleRE06
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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 for a run
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2. Changing calorimeter geometries without re-building a world volume
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3. Defining geometrical regions and setting production thresholds
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for each region
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4. Demonstrating the use of primitive scorer and filter classes without
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implementing sensitive detector class
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5. Demonstrating the use of parallel scoring geometry and associating
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parallel world scoring process
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6. Measuring the timing spent for each region, both for all particle
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types and for e+/e-
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It was moved in extended examples from novice/N07 with removal of
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novice examples.
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**********************************************************************
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Note: Since this example utilizes its own RE06SteppingVerbose for the
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timing measurement, the user cannot get the ordinary verbosity with
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/tracking/verbose.
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**********************************************************************
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1- Utilizing a concrete run class derived from G4Run base class for
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accumulating physics quantities for 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, RE06Run is the class derived from G4Run. In the method
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RE06Run::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, RE06RunAction
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is the class which instantiating RE06Run class object. In
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RE06RunAction::EndOfRunAction(const G4Run*) method, RE06Run 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 RE06StackinAction instead of sensitive detector class.
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RE06StackingAction::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 RE06DetectorConstruction, 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 RE06DetectorConstruction::SetNumberOfLayers(G4int)
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for changing the number of parameterized volumes, and also
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RE06DetectorConstruction::SetSerialGeometry(G4bool) for changing the
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position of placed volumes.
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3- Defining geometrical regions and 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 RE06DetectorConstruction::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 RE06PhysicsList::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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4- Demonstrating the use of primitive scorer and filter classes without
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implementing sensitive detector class
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In RE06DetectorConstruction::SetupDetector() method, concrete classes
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G4PSEnergyDeposit, G4PSNofSecondary, G4PSTrackLength, G4PSNofStep and
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G4PSMinKinEAtGeneration, all of thich are derivalable of G4VPrimitiveScorer,
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are used to define the sensitivity of the calorimeter. All of them are
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registered to G4MultiFunctionalDetector and this detector object is set
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to the logical volume. G4SDParticleFilter is used to define the particle
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type(s) to be scored.
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In RE06Run::RecordEvent() method, the way of retreiving G4THitsMap
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from each primitive scorer via G4HCofThisEvent is demonstrated.
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In RE06RunAction::EndOfRunAction(), Run is summarized with data kept
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in RE06Run class object.
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5- Demonstrating the use of parallel scoring geometry and associating
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parallel world scoring process
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In RE06PhysicsList::ConstructGeneral(), G4ParallelWorldScoringProcess is
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assigned to all the particle types. This process invokes sensitive detectors
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(and scorers) defined in the parallel world "ParallelScoringWorld", the
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name of the parallel world which is defined in main() (exampleRE06.cc) as
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an argument of RE06ParallelWorld constructor.
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As implemented in RE06ParallelWorld::SetupGeometry(), the world volume of
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the parallel world is obtained by GetWorld() method as a clone copy of the
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world volume of the mass geometry. The user should not create the world volume.
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RE06ParallelWorld defines three cylindrical volumes, each of them is
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located at the same position as three sandwitch calorimeters defined
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in the mass geometry (RE06DetectorConstruction). Each cylinder is replicated
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in Rho to define 20 layers, and scores the same quantities as the mass geometry.
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These three cylinders are relocated accordingly when the mass geometry is
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modified by RE06DetectorConstruction::SetSerialGeometry().
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6- Measuring the timing spent for each region, both for all particle
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types and for e+/e-
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RE06SteppingVerbose class has two G4SliceTimer class objects for each
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detector region. One G4SliceTimer is measuring the time spent by a step
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in a region for all types of particles, and another is measuring for
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e+/e- only.
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RE06SteppingVerbose::InitializeTimers() is invoked by RE06RunAction::
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BeginOfRunAction(), and checks the number of regions appear in the
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geometry and instantiates the necessary number of timers. Thus, this
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RE06SteppingVerbose class can be used for any kind of geometry the user
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defines without any modification. Given G4VSteppingVerbose is not invoked
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if the verbosity of G4SteppingManager is 0, this verbosity is set to 1.
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NewStep() and StepInfo() are the methods defined in G4VSteppingVerbose
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base class, and they are invoked at the beginning and the end of every
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step, respectively, from G4SteppingManager. Thus, these methods are
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utilized in RE06SteppingVerbose to start/resume and pause the timer.
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RE06SteppingVerbose::Report() method is used by RE06RunAction::
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EndOfRunAction() to get the timing measured.
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7- Macro files
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exampleRE06.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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8- UI commands defined in this example
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Command /RE06/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 /RE06/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 /RE06/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 /RE06/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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