Gabriele Cosmo
176 lines
7.2 KiB
Plaintext
176 lines
7.2 KiB
Plaintext
$README, v 1.0 26.11.2004 Joanna Weng $
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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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GFLASH Examples
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--------------
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These examples demonstrate the use of the GFLASH parameterisation library.
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They use the GFLASH equations (hep-ex/0001020, Grindhammer & Peters)
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to parametrise electromagnetic showers in matter.
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In these examples the calorimeter is a simple cube,
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which consists of 10 x 10 crystals of PbWO4 (CMS like).
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Briefly, whenever a e-/e+ enters the calorimeter, it is parametrised if it
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has a minimum energy and the shower is expected to be contained
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in the calorimeter (so called " parameterisation envelope").
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If this is fullfilled the particle is killed, as well as all secondaries,
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and the energy is deposited according to the GFLASH equations.
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The examples show how to interface GFLASH to your application.
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The simulation time is measured, so the user can see immediately
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the speed up by using GFLASH.
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Geometry and parametrisation is defined in different ways in the set of three equivalent
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(in terms of produced showers) examples: gflash1, gflash2 and gflash3, to demonstrate
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how to use the parametrisation, sensitive detectors and parallel geometry.
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The classes which are the same in all three examples have the names with ExGflash prefix while
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the names of classes specific to each example have the prexix ExGflash[1,2,3].
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The gflasha example - allow histogramming of show profiles and fine tuning
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of gflash parametrization for homogeneous medium. This examples has a standalone documentation.
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Note: Instead of particle gun the gps class is used here for particle generation.
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Briefly
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-------
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Table below presents in which world/geometry (mass or parallel) each of the elements is defined.
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+------------------------------+----------+--------------+--------------+
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| Example | gflash1 | gflash2 | gflash3 |
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+------------------------------+----------+--------------+--------------+
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| Block of material | mass geo | mass geo | mass geo |
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+------------------------------+----------+--------------+--------------+
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| Crystals (readout geometry) | mass geo | mass geo | parallel geo |
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+------------------------------+----------+--------------+--------------+
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| Sensitive detector | mass geo | mass geo | parallel geo |
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+------------------------------+----------+--------------+--------------+
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| Envelope for parametrisation | mass geo | parallel geo | mass geo |
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+------------------------------+----------+--------------+--------------+
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Example gflash1:
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Uses only the mass geometry, with each crystal defined as a volume,
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with parametrisation attached to the envelope in the mass geometry.
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Geometry and sensitive detector are defined in:
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ExGflash1DetectorConstruction
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ExGflash1SensitiveDetector
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Example gflash2:
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Uses mass geometry to create volumes and to create a sensitive detector
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for storing hits, but parametrisation is attached to the envelope
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in the parallel geometry (see also examples/extended/parametrisations/Par01).
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Geometry and sensitive detector are defined in:
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ExGflash2DetectorConstruction
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ExGflash2ParallelWorld
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ExGflash2SensitiveDetector
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Example gflash3:
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Uses mass geometry to create the main volume (homogeneous material) and use it
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as an envelope for the parametrisation, but the readout geometry (crystals)
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are defined in the parallel geometry, together with the sensitive detector
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to store the hits.
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Geometry and sensitive detector are defined in:
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ExGflash3DetectorConstruction
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ExGflash3ParallelWorld
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ExGflash3SensitiveDetector
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Details of implementation:
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-------
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Example gflash1:
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To use GFLASH the user has to implement the following:
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- ExGflash1DetectorConstruction::ConstructSD() :
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Here GFLASH has to be initialized and assigend to the envelope,
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where it should be active (here our calorimeter = fCalo_log )
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// **********************************************
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// * Initializing shower modell
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// ***********************************************
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G4cout << "Creating shower parameterization models" << G4endl;
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fFastShowerModel = new GFlashShowerModel("fFastShowerModel", fRegion);
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fParameterisation = new GFlashHomoShowerParameterisation(pbWO4);
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fFastShowerModel->SetParameterisation(*fParameterisation);
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fParticleBounds = new GFlashParticleBounds();
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fFastShowerModel->SetParticleBounds(*fParticleBounds);
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fHitMaker = new GFlashHitMaker();
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fFastShowerModel->SetHitMaker(*fHitMaker);
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G4cout<<"end shower parameterization."<<G4endl;
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- ExGflash1SensitiveDetector:
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It is mandatory to use G4VGFlashSensitiveDetector as (additional)
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base class for the sensitive detector.
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Here it is necessary to implement a seperate
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interface, where the GFlash spots are processed.
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(ProcessHits(G4GFlashSpot*aSpot ,G4TouchableHistory* ROhist))
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The separate interface is used, because the GFLASH spots contains
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(naturally) less information than the full simulation.
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Example gflash2:
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- ExGflash2.cc:
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Parallel world needs to be registered;
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Fast simulation is activated for parallel world (where envelope is);
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- ExGflash2DetectorConstruction:
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Only main geometry and SD are created;
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- ExGflash2ParallelWorld:
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Construction of identical volume for the main box as in the mass geometry,
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but with dummy material (it is not used anyway);
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Creation of G4Region associated to G4LogicalVolume;
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Initialization of GFlash, attaching it to the envelope (G4Region);
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- ExGflash2SensitiveDetector:
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Uses pointer to ExGflash2ParallelWorld to get the crystals for the readout;
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Example gflash3:
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- ExGflash3.cc:
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Parallel world needs to be registered;
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Physics of the parallel world needs to be registered so sensitive detector can
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collect hits;
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Fast simulation is activated for mass world (where envelope is);
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- ExGflash3DetectorConstruction:
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Only main volume (box) with material is created;
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Creation of G4Region associated to G4LogicalVolume of that box;
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Initialization of GFlash, attaching it to the envelope (G4Region);
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- ExGflash3ParallelWorld:
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Construction of identical volume for the main box as in the mass geometry,
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but with dummy material (it is not used anyway);
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Construction of individual crystals for the readout geometry;
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Creation of the sensitive detector;
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- ExGflash3SensitiveDetector:
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Uses pointer to ExGflash3DetectorConstruction to get the crystals for the readout;
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Macros
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vis.mac - macro for use in interactive mode (default, if no arguments are specified)
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test.mac - macro for tests: 50 GeV electrons are shot in the direction of the detector
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(along z axis), 10 times. As they enter the parametrisation envelope,
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the GFlash parametrisation is invoked and energy is deposited.
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The results are printed out:
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- energy in the most central crystal
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- energy in 3x3 crystals
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- energy in 5x5 crystals
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- number of created deposits
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- simulation time per event
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