Gabriele Cosmo
140 lines
4.4 KiB
Plaintext
140 lines
4.4 KiB
Plaintext
=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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GFLASHa Example
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---------------
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This example demonstrating usage 'gflash' shower parameterisation
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in homogeneous calorimeter. Compare with glash1,2,3 the histograms
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have been added in this example. This makes it possible to use this
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example for fine tuning of GFLASH parameters.
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This example allows to compare the shower profiles from fast simulation
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with full simulation by histograming of longitudinal (slice)
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and radial profiles with different "binning".
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Then GFlash fast simulation can be "tuned" via modification
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of the model parameters file:
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include/ExGflashHomoShowerTuning.hh
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in this example.
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PHYSICS LIST
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------------
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The Physics list factory is used in this example.
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The default physics list is FTFP_BERT which has EM opt0.
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Additionally, the G4FastSimulationPhysics physics
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constructor was created to insert the G4FastSimulationManager Process
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that is making the interface between the fast simulation and the tracking.
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The default PHYSICS list may be changed via setting of the PHYSLIST environment
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variable, e.g.:
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export PHYSLIST=FTFP_BERT_EMZ # for FTFP_BERT with opt 4 EM physics
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GEOMETRY DEFINITION
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-------------------
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In this example 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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Geometry, sensitive detector and hits are defined respectively in:
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ExGflashDetectorConstruction
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ExGflashSensitiveDetector
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ExGflashHit
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The geometry can be redefined in PreInit state via commands:
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/exgflash/det/setNbCrys ncrys
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/exgflash/det/setCrysWidth width [cm]
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/exgflash/det/setCrysLength length [cm]
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Materials can be chosen from Nist Materials: G4_Air G4_WATER ...
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e.g.: /exgflash/det/setMat G4_PbWO4 see also: csi.mac
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HIT SCORING
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-----------
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The virtual cylinder sliced longitudinally (slice) and radially (ring) was used.
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The size of the slices and rings are expressed in radiation
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length units and Moliere radius (Rm) units for rings. The number
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of division and division size in fraction of units and can be changed.
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e.g.: /exgflash/det/setLbin 20 1. ---> 20 slices of 1. radl
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/exgflash/det/setRbin 5 0.25 ---> 5 rings of 0.25 Rm
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(MaxBin = 500 in both directions)
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In ExGflashEventAction class the arrays corresponded slices and rings was
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created and filled with hists information. These arrays where use to fill
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histograms later.
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VISUALIZATION
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-------------
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The Visualization Manager is set in the main().
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The initialization of the drawing is done via the commands /vis/...
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in the macro vis.mac. To get visualization use:
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/control/execute vis.mac
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HOW TO START ?
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--------------
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- Execute ExGflasha in 'batch' mode from macro files
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% ExGflasha test.mac
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- Execute ExGflasha in 'interactive mode' with visualization
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% ExGflasha
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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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The GFLASH activated via:
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/GFlash/flag 1
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HISTOGRAMS
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----------
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ExGflasha produces several histograms:
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The histograms defined in ExGflashHistoManager class
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Content of these histo:
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h0 : energy deposit per event
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h1 : the number of hits per event
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h2 : the energy per hit ( in MeV )
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p0 : longitudinal energy profile
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p1 : radial energy profile
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p2 : cumulated longitudinal energy profile
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p3 : cumulated radial energy profile
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To define the output file name with histograms, use the UI command :
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"/analysys/setFileName name"
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MACROS
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------
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The macros to run in batch mode:
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test.mac - default macro for example testing, it show how to use different application commands: redefine the histograms and profiles, change the geometry and material, etc
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csi.mac - like test.mac but produce profiles in CsI Material
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testLong.mac - make the runs with more statistics using default geometry and histograms setting, the material is G4_PbWO4
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csiLong.mac - show how to run testLong.mac with different material (CsI)
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Each macro executes two runs with fast simulation flag ON (the output file
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name is set to gflash01.root ) and OFF (the output file name is set to gflash00.root )
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In addition, the ROOT macros cmpL.C, cmpR.C and cmpE.C file are provided,
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which can be used to draw superimposed full and fast histograms for radial
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and lateral profiles and also the normalized total energy deposition
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in calorimeter.
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