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0002
0003 =========================================================
0004 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0005 =========================================================
0006
0007 TestEm18
0008 --------
0009 This example allows to study the various contributions of the energy lost
0010 by a charged particle in a single layer of an homogeneous material.
0011 See any textbook of interactions of charged particles with matter, in particular :
0012 1- geant4.web.cern.ch --> UserSupport --> Physics Reference Manual
0013 2- lappweb.in2p3.fr/~maire/tutorials/index.html
0014
0015 1- GEOMETRY DEFINITION
0016
0017 It is a simple cubic box of homogeneous material.
0018 Two parameters define the geometry :
0019 - the material of the box,
0020 - the thickness of the box.
0021
0022 The default geometry (1 cm of water) is constructed in DetectorConstruction,
0023 but the above parameters can be changed interactively via the commands
0024 defined in DetectorMessenger.
0025
0026 2- PHYSICS
0027
0028 The physics list contains the 'standard' electromagnetic processes.
0029 However the MultipleScattering is not registered, in order to focuse on
0030 fluctuations of to energy loss alone.
0031
0032 3- BEAM
0033
0034 The primary kinematic is a single particle starting at the edge
0035 of the box. The type of the particle and its energy are set in
0036 PrimaryGeneratorAction (e- 10 MeV), and can be changed via the G4
0037 build-in commands of ParticleGun class.
0038
0039 4- RUN
0040
0041 During the tracking of the incident particle, by default, the secondary
0042 particles are immediately killed, after that their energy has been registered
0043 (see SteppingAction and StackingAction).
0044 Therefore, we study here the various components of the total energy lost
0045 by the incident particle, not the energy deposited in a layer of finite
0046 thickness.
0047 With the option /testEm/trackSecondaries one can compute and plot the energy
0048 deposited in the layer. See edep.mac
0049
0050 At EndOfRun, the above results are compared with 'reference' values,
0051 i.e. the input data read from EnergyLoss and Range tables.
0052 See reference 2 : Energy-Range relation, slide 4.
0053
0054 5- HISTOGRAMS
0055
0056 The test contains 13 built-in 1D histograms, which are managed by
0057 G4AnalysisManager and its Messenger.
0058
0059 1 step size of primary track
0060 2 energy continuously deposited along primary track
0061 3 energy transfered to secondaries by ionisation
0062 4 energy transfered to secondaries by Bremsstrahlung
0063 5 energy transfered to secondaries by (e+,e-) production
0064 6 total energy transfered to secondaries
0065 7 total energy lost by primary track
0066 8 total energy lost by primary track from energy balance
0067 9 energy continuously deposited along secondary tracks
0068 10 total energy deposited
0069 11 energy spectrum of gamma
0070 12 energy spectrum of e-
0071 13 energy spectrum of e+
0072
0073 The histograms are defined in HistoManager.
0074
0075 The histos can be activated individually with the command :
0076 /analysis/h1/set id nbBins valMin valMax unit
0077 where 'unit' is the desired unit for the histo (MeV or KeV, cm or mm, etc..)
0078
0079 One can control the name of the histograms file with the command:
0080 /analysis/setFileName name (default testem18)
0081
0082 It is possible to choose the format of the histogram file : root (default),
0083 xml, csv, by using namespace in HistoManager.hh
0084 For convenience, few simple Root macros are provided : plotHisto.C pixe.C
0085 It is also possible to print selected histograms on an ascii file:
0086 /analysis/h1/setAscii id
0087 All selected histos will be written on a file name.ascii (default testem18)
0088
0089 6- VISUALIZATION
0090
0091 The Visualization Manager is set in the main().
0092 The initialisation of the drawing is done via the commands
0093 /vis/... in the macro vis.mac. To get visualisation:
0094 > /control/execute vis.mac
0095
0096 The detector has a default view which is a longitudinal view of the box.
0097 The tracks are drawn at the end of event, and erased at the end of run.
0098
0099 7- HOW TO START ?
0100
0101 execute TestEm18 in 'batch' mode from macro files :
0102 % TestEm18 electron.mac
0103
0104 execute TestEm18 in 'interactive mode' with visualization :
0105 % TestEm18
0106 Idle> control/execute vis.mac
0107 ....
0108 Idle> type your commands
0109 ....
0110 Idle> exit
0111
0112 Macros provided in this example:
0113 - csda.mac: test independance of user step max
0114 - edep.mac: track secondary particles and plot energy deposited
0115 - electron.mac: e- (10 MeV) on 1 cm of water
0116 - ion.mac: ion C12 (4 GeV) on 1 cm of water
0117 - muon.mac: mu+ (1 TeV) on 1 m of water
0118 - pixe.mac: proton (20 MeV) on 50 um of gold. Plot gamma pixe
0119 - proton.mac: proton (1 GeV) on 10 cm of water
0120 - plotHisto.C, pixe.C: Root macros
0121
0122 Macros to be run interactively:
0123 - vis.mac: To activate visualization
