Gabriele Cosmo
109 lines
4.2 KiB
Plaintext
109 lines
4.2 KiB
Plaintext
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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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TestEm9
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Demonstrate electromagnetic physics in crystal calorimeters.
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How to define cut-per-region.
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1- GEOMETRY DEFINITION
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The geometry consists of the vertex detector (VD), the electromagnetic
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calorimeter (EM), and the muon identifier (MU). Detector layout along
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the Z axis.
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VD consisted of 3 layers of Si with pads structured along the X axis.
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Between VD and EM there are 2 active absorbers (scintillators).
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EM is the matrix 5x5 of heavy crystals. MU consist of 2 active absorbers
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(scintillators) and the iron plate between.
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2 regions additional to the World are defined: VertexDetector and
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MuonDetector. For testing purposes first absorber of MU is included in
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the region of VD.
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Material of calorimeter and absorber can be choosen:
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Air Water lAr Al Fe BGO PbWO4 Pb.
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eg: /testem/det/CalMat PbWO4
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/testem/det/AbsMat Al
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The size of the detector can be changed also.
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eg: /testem/det/EcalLength 20 cm
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/testem/det/EcalWidth 5 cm
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/testem/det/update ---> rebuild the geometry
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2- PHYSICS LISTS
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Physics Lists are based on modular design. Several modules are instantiated:
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1. Transportation
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2. EM physics
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3. Decays
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4. StepMax - for step limitation
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The following options for EM physics using builders from physics_lists
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sub-package are available:
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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" similar fast simulation
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- "emstandard_opt3" best standard EM options - analog to "local" above
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- "emstandard_opt4" best current advanced EM options standard + lowenergy
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- "emstandardWVI" standard EM physics and WentzelVI multiple scattering
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- "emstandardSS" standard EM physics and single scattering model
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- "emstandardGS" standard EM physics and Goudsmit-Saunderson multiple scatt.
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- "emlivermore" low-energy EM physics using Livermore data
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- "empenelope" low-energy EM physics implementing Penelope models
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- "emlowenergy" low-energy EM physics implementing experimental
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low-energy models
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A local builder, PhysListEmStandard "local" (similar to opt0) is also
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available.
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Optional components can be added:
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- "elastic" elastic scattering of hadrons
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- "binary" QBBC configuration of hadron/ion inelastic models
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- "gamma_nuc" gamma- and electro-nuclear processes
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- "stopping" stopping processes
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3- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle which hits the
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cylinder perpendicular to the input face. The type of the particle
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and its energy are set in the PrimaryGeneratorAction class, and can
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changed via the G4 build-in commands of G4ParticleGun class.
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4- OUTPUT
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The batch regime of simulation can be started
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$G4WORKDIR/bin/$G4SYSTEM/TestEm9 TestEm9.in
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where TestEm9.in is the example of macro file for batch job.
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As a result of simulation the number of secondaries produced
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in different regions are averaged. The average energy depositions
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in active absorbers and EM as well as RMS of these values are shown.
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The number of hits in pads of VD is printed out.
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5- VISUALISATION
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To use visualisation the environment variable G4_VIS_USE should be
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defined. An interactive session starts if no macro file is specified
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in the command line:
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$G4WORKDIR/bin/$G4SYSTEM/TestEm9
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To start visualisation one can issur
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>/control/execute vis.mac
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>/run/beamOn 1
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6- ANALYSIS
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Number of histograms are built inside the example using internal
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analysis sub-package. Histograms are saved in a root file.
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Histogram booking and saving is done only if any of histogram
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/testem/histo/fileName myname
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/testem/histo/setHisto id nbins xmin xmax unit
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