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0002
0003 =========================================================
0004 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0005 =========================================================
0006
0007 TestEm17
0008 --------
0009 This example is intended to check implementation of the processes
0010 of muon interactions: ionization, direct (e+,e-) production, mu+mu-
0011 pair production, bremsstrahlung, and mu-nuclear interaction.
0012 It allows to compute differential cross sections (as function of the
0013 energy transfered to secondaries), total cross sections, and to compare
0014 with analytic calculations.
0015
0016 1- GEOMETRY DEFINITION
0017
0018 It is a single box of homogeneous medium.
0019 Two parameters define the geometry :
0020 - the material of the box,
0021 - the (full) size of the box.
0022
0023 The default geometry (1 m of Iron) is constructed in
0024 DetectorConstruction, but the above parameters can be changed
0025 interactively via the commands defined in DetectorMessenger.
0026
0027 2- PHYSICS LIST
0028
0029 The Physics List of the example uses the main physics constructor
0030 (builder) called "local", which includes only muon, pion, and proton
0031 processes under study. As an alternative standard "emstandard_opt0"
0032 and "emstandard_opt4" constructors may be used.
0033
0034 Default energy range for EM processes in this example
0035 is from 100*eV to 1000*PeV.
0036
0037 Optionally "muNucl" builder may be added activating muon-nuclear
0038 inelastic interaction.
0039
0040 3- AN EVENT : THE PRIMARY GENERATOR
0041
0042 The primary kinematic consists of a single particle starting at the edge
0043 of the box. The type of the particle and its energy are set in
0044 PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
0045 build-in commands of ParticleGun class (see the macros provided with
0046 this example).
0047
0048 4- PHYSICS
0049
0050 The incident particle is a muon. During the tracking, secondary
0051 particles are killed.
0052
0053 The number of interactions are plotted as a function of the energy
0054 transfered to the secondaries.
0055 The total number of interactions is recorded, and the total cross
0056 section computed from this.
0057
0058 At RunAction::EndOfRun(..), the above results are compared with analytical
0059 calculations. The functions computing the theoretical cross sections have been
0060 provided by the G4 MEPhI group, and implemented in MuCrossSections class.
0061
0062 5- HISTOGRAMS
0063
0064 The test contains built-in 1D histograms for muons filled during
0065 Monte Carlo simulation, which are managed by the HistoManager class
0066 and its Messenger:
0067
0068 1 Relative muon transferred energy distribution
0069 (log10(eps/Emu kin) for knock-on electrons (ionization)
0070 2 -"- direct (e+,e-) pair production by muons
0071 3 -"- bremsstrahlung by muons
0072 4 -"- nuclear interaction by muons
0073 5 ionistion for hadrons
0074 6 (e+,e-) pair production by hadrons
0075 7 bremsstrahlung by hadrons
0076 8 direct mu+,mu- pair production by muons
0077
0078 The histos can be activated individually with the command :
0079 /testem/histo/setHisto id nbBins valMin valMax :
0080 min and max values of log10(eps/Emu kin).
0081
0082 At EndOfRun the corresponding histos for analytic calculations are
0083 automatically created and filled (histo 11 to 14, and 18).
0084
0085 One can control the name and the type of the histograms file with
0086 the command:
0087 /testem/histo/setFileName name (default testem17)
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
0097 box.
0098
0099 The tracks are drawn at the end of event, and erased at the end of run.
0100
0101 7- HOW TO START ?
0102
0103 execute TestEm17 in 'batch' mode from macro files :
0104 % TestEm17 allproc.mac
0105
0106 execute TestEm17 in 'interactive mode' with visualization :
0107 % TestEm17
0108 Idle> control/execute vis.mac
0109 ....
0110 Idle> type your commands
0111 ....
0112 Idle> exit
