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0001 \page ExampleTestEm18 Example TestEm18
0002
0003 This example allows to study the various contributions of the energy lost
0004 by a charged particle in a single layer of an homogeneous material.
0005 See any textbook of interactions of charged particles with matter, in particular :
0006 - 1- geant4.web.cern.ch --> UserSupport --> Physics Reference Manual
0007 - 2- lappweb.in2p3.fr/~maire/tutorials/index.html
0008
0009 ## GEOMETRY DEFINITION
0010
0011 It is a simple cubic box of homogeneous material.
0012 Two parameters define the geometry :
0013 - the material of the box,
0014 - the thickness of the box.
0015
0016 The default geometry (1 cm of water) is constructed in DetectorConstruction,
0017 but the above parameters can be changed interactively via the commands
0018 defined in DetectorMessenger.
0019
0020 ## PHYSICS
0021
0022 The physics list, PhysicsList, contains the 'standard' electromagnetic processes.
0023 However the MultipleScattering is not registered, in order to focuse on
0024 fluctuations of to energy loss alone.
0025
0026 ## BEAM
0027
0028 The primary kinematic is a single particle starting at the edge
0029 of the box. The type of the particle and its energy are set in
0030 PrimaryGeneratorAction (e- 10 MeV), and can be changed via the G4
0031 build-in commands of G4ParticleGun class.
0032
0033 ## RUN
0034
0035 During the tracking of the incident particle, by default, the secondary
0036 particles are immediately killed, after that their energy has been registered
0037 (see SteppingAction and StackingAction).
0038 Therefore, we study here the various components of the total energy lost
0039 by the incident particle, not the energy deposited in a layer of finite
0040 thickness.
0041 With the option /testEm/trackSecondaries one can compute and plot the energy
0042 deposited in the layer. See edep.mac
0043
0044 At EndOfRun, the above results are compared with 'reference' values,
0045 i.e. the input data read from EnergyLoss and Range tables.
0046 See reference 2 : Energy-Range relation, slide 4.
0047
0048 ## HISTOGRAMS
0049
0050 The test contains 13 built-in 1D histograms, which are managed by
0051 G4AnalysisManager and its messenger.
0052
0053 - 1: step size of primary track
0054 - 2: energy locally deposited along primary track
0055 - 3: energy transfered to secondaries by ionisation
0056 - 4: energy transfered to secondaries by Bremsstrahlung
0057 - 5: energy transfered to secondaries by (e+,e-) production
0058 - 6: total energy transfered to secondaries
0059 - 7: total energy lost by primary track
0060 - 8: total energy lost by primary track from energy balance
0061 - 9: energy continuously deposited along secondary tracks
0062 - 10: total energy deposited
0063 - 11: energy spectrum of gamma
0064 - 12: energy spectrum of e-
0065 - 13: energy spectrum of e+
0066
0067 The histograms are defined in HistoManager.
0068
0069 The histos can be activated individually with the command :
0070 ```
0071 /analysis/h1/set id nbBins valMin valMax unit
0072 ```
0073 where 'unit' is the desired unit for the histo (MeV or KeV, cm or mm, etc..)
0074
0075 One can control the name of the histograms file with the command:
0076 ```
0077 /analysis/setFileName name (default testem18)
0078 ```
0079
0080 It is possible to choose the format of the histogram file : root (default),
0081 xml, csv, by changing the default file type in HistoManager.cc
0082 For convenience, few simple Root macros are provided : plotHisto.C pixe.C
0083
0084 It is also possible to print selected histograms on an ascii file:
0085 ```
0086 /analysis/h1/sweAscii id
0087 ```
0088 All selected histos will be written on a file name.ascii (default testem18)
0089
0090 ## VISUALIZATION
0091
0092 The Visualization Manager is set in the main().
0093 The initialisation of the drawing is done via the commands
0094 /vis/... in the macro vis.mac. To get visualisation:
0095 ```
0096 > /control/execute vis.mac
0097 ```
0098
0099 The detector has a default view which is a longitudinal view of the box.
0100 The tracks are drawn at the end of event, and erased at the end of run.
0101
0102 ## HOW TO START ?
0103
0104 - Execute TestEm18 in 'batch' mode from macro files :
0105 ```
0106 % ./TestEm18 electron.mac
0107 ```
0108
0109 - Execute TestEm18 in 'interactive mode' with visualization :
0110 ```
0111 % ./TestEm18
0112 Idle> control/execute vis.mac
0113 ....
0114 Idle> type your commands
0115 ....
0116 Idle> exit
0117 ```
0118
0119 Macros provided in this example:
0120 - csda.mac: test independance of user step max
0121 - edep.mac: track secondary particles and plot energy deposited
0122 - electron.mac: e- (10 MeV) on 1 cm of water
0123 - ion.mac: ion C12 (4 GeV) on 1 cm of water
0124 - muon.mac: mu+ (1 TeV) on 1 m of water
0125 - pixe.mac: proton (20 MeV) on 50 um of gold. Plot gamma pixe
0126 - proton.mac: proton (1 GeV) on 10 cm of water
0127 - plotHisto.C, pixe.C: Root macros
0128
0129 Macros to be run interactively:
0130 - vis.mac: To activate visualization
