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0001 \page ExampleTestEm14 Example TestEm14
0002
0003 - How to compute cross sections from the direct evaluation of the mean
0004 free path.
0005 - How to plot final state of a process.
0006
0007 ## GEOMETRY DEFINITION
0008
0009 It is a single box representing a 'semi infinite' homogeneous medium.
0010 Two parameters define the geometry :
0011 - the material of the box,
0012 - the (full) size of the box.
0013
0014 The default geometry (100 m of water) is constructed in
0015 DetectorConstruction, but the above parameters can be changed
0016 interactively via the commands defined in DetectorMessenger.
0017
0018 ## PHYSICS LIST
0019
0020 The physics list contains the standard electromagnetic processes.
0021 In order not to introduce 'artificial' constraints on the step size, the
0022 multiple scattering is not instanciated, and all processes are
0023 registered as discrete : there is no continuous energy loss.
0024
0025 ## AN EVENT : THE PRIMARY GENERATOR
0026
0027 The primary kinematic consists of a single particle starting at the edge
0028 of the box. The type of the particle and its energy are set in
0029 PrimaryGeneratorAction (1 MeV gamma), and can be changed via the G4
0030 build-in commands of G4ParticleGun class (see the macros provided with
0031 this example).
0032
0033 ## PHYSICS
0034
0035 An event is killed at the first interaction of the incident paticle.
0036 The absorption length, also called mean free path, is computed as
0037 the mean value of the track length of the incident particle.
0038 This is why the medium must be 'infinite' : to be sure that interaction
0039 occurs at any events.
0040
0041 The result is compared with the 'input' data, i.e. with the cross
0042 sections stored in the PhysicsTables and used by Geant4.
0043
0044 The energy spectrum and the angular distribution of the scattered
0045 particle (if any) and of the created secondaries are plotted (see
0046 SteppingAction).
0047
0048 A set of macros defining various run conditions are provided.
0049 The processes are actived/inactived in order to survey the processes
0050 individually.
0051
0052 ## HISTOGRAMS
0053
0054 The test contains 6 built-in 1D histograms, which are managed by the
0055 HistoManager class and its messenger, HistoMessenger. The histos can be individually
0056 activated with the command :
0057 /analysis/h1/set id nbBins valMin valMax unit
0058 where unit is the desired unit for the histo (MeV or keV, etc..)
0059 (see the macros xxxx.mac).
0060
0061 - 1 : "scattered primary particle: energy spectrum"
0062 - 2 : "scattered primary particle: costheta distribution"
0063 - 3 : "charged secondaries: energy spectrum"
0064 - 4 : "charged secondaries: costheta distribution"
0065 - 5 : "neutral secondaries: energy spectrum"
0066 - 6 : "neutral secondaries: costheta distribution"
0067
0068 The histograms are managed by the HistoManager class and its messenger,
0069 HistoMessenger
0070 The histos can be individually activated with the command :
0071 ```
0072 /analysis/h1/set id nbBins valMin valMax unit
0073 ```
0074 where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
0075
0076 One can control the name of the histograms file with the command:
0077 ```
0078 /analysis/setFileName name (default testem14)
0079 ```
0080
0081 It is possible to choose the format of the histogram file : root (default),
0082 hdf5, xml, csv, by changing the default file type in HistoManager.cc
0083
0084 It is also possible to print selected histograms on an ascii file:
0085 ```
0086 /analysis/h1/setAscii id
0087 ```
0088 All selected histos will be written on a file name.ascii (default testem14)
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
0100 box.
0101
0102 The tracks are drawn at the end of event, and erased at the end of run.
0103
0104 ## HOW TO START ?
0105
0106 - Execute TestEm14 in 'batch' mode from macro files :
0107 ```
0108 % ./TestEm14 compt.mac
0109 ```
0110
0111 - Execute TestEm14 in 'interactive mode' with visualization :
0112 ```
0113 % ./TestEm14
0114 Idle> control/execute vis.mac
0115 ....
0116 Idle> type your commands
0117 ....
0118 Idle> exit
0119 ```
0120
0121 Macros provided in this example:
0122 - anni.mac: e+ (100 MeV) on Aluminium
0123 - atomicDeexcitation: gamma (80 keV) on Tellurium
0124 - compton.mac: gamma (300 keV) on Aluminium
0125 - conv.mac: gamma (20 MeV) on Lead
0126 - convtomu.mac: gamma (100 TeV) on Iron
0127 - electron.mac: e- (100 MeV) on Aluminium
0128 - gamma.mac: gamma (100 keV) on Water
0129 - photoelec.mac: gamma (80 keV) on Gold
0130 - proton.mac: proton (100 MeV) on Water
0131
