| Geant4 Cross Reference |
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2 2
3 ========================================= 3 =========================================================
4 Geant4 - an Object-Oriented Toolkit for S 4 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
5 ========================================= 5 =========================================================
6 6
7 TestEm17 7 TestEm17
8 -------- 8 --------
9 This example is intended to check impl 9 This example is intended to check implementation of the processes
10 of muon interactions: ionization, dire 10 of muon interactions: ionization, direct (e+,e-) production, mu+mu-
11 pair production, bremsstrahlung, and mu-nucl 11 pair production, bremsstrahlung, and mu-nuclear interaction.
12 It allows to compute differential cross sect 12 It allows to compute differential cross sections (as function of the
13 energy transfered to secondaries), total cro 13 energy transfered to secondaries), total cross sections, and to compare
14 with analytic calculations. 14 with analytic calculations.
15 15
16 1- GEOMETRY DEFINITION 16 1- GEOMETRY DEFINITION
17 17
18 It is a single box of homogeneous medium. 18 It is a single box of homogeneous medium.
19 Two parameters define the geometry : 19 Two parameters define the geometry :
20 - the material of the box, 20 - the material of the box,
21 - the (full) size of the box. 21 - the (full) size of the box.
22 22
23 The default geometry (1 m of Iron) is constr 23 The default geometry (1 m of Iron) is constructed in
24 DetectorConstruction, but the above paramete 24 DetectorConstruction, but the above parameters can be changed
25 interactively via the commands defined in De 25 interactively via the commands defined in DetectorMessenger.
26 26
27 2- PHYSICS LIST 27 2- PHYSICS LIST
28 28
29 The Physics List of the example uses the mai 29 The Physics List of the example uses the main physics constructor
30 (builder) called "local", which includ 30 (builder) called "local", which includes only muon, pion, and proton
31 processes under study. As an alternati 31 processes under study. As an alternative standard "emstandard_opt0"
32 and "emstandard_opt4" constructors may 32 and "emstandard_opt4" constructors may be used.
33 33
34 Default energy range for EM processes 34 Default energy range for EM processes in this example
35 is from 100*eV to 1000*PeV. 35 is from 100*eV to 1000*PeV.
36 36
37 Optionally "muNucl" builder may be add 37 Optionally "muNucl" builder may be added activating muon-nuclear
38 inelastic interaction. 38 inelastic interaction.
39 39
40 3- AN EVENT : THE PRIMARY GENERATOR 40 3- AN EVENT : THE PRIMARY GENERATOR
41 41
42 The primary kinematic consists of a single p 42 The primary kinematic consists of a single particle starting at the edge
43 of the box. The type of the particle and its 43 of the box. The type of the particle and its energy are set in
44 PrimaryGeneratorAction (mu+ 10 TeV), and can 44 PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
45 build-in commands of ParticleGun class (see 45 build-in commands of ParticleGun class (see the macros provided with
46 this example). 46 this example).
47 47
48 4- PHYSICS 48 4- PHYSICS
49 49
50 The incident particle is a muon. During the 50 The incident particle is a muon. During the tracking, secondary
51 particles are killed. 51 particles are killed.
52 52
53 The number of interactions are plotted as a 53 The number of interactions are plotted as a function of the energy
54 transfered to the secondaries. 54 transfered to the secondaries.
55 The total number of interactions is recorded 55 The total number of interactions is recorded, and the total cross
56 section computed from this. 56 section computed from this.
57 57
58 At RunAction::EndOfRun(..), the above 58 At RunAction::EndOfRun(..), the above results are compared with analytical
59 calculations. The functions computing 59 calculations. The functions computing the theoretical cross sections have been
60 provided by the G4 MEPhI group, and implemen 60 provided by the G4 MEPhI group, and implemented in MuCrossSections class.
61 61
62 5- HISTOGRAMS 62 5- HISTOGRAMS
63 63
64 The test contains built-in 1D histograms for 64 The test contains built-in 1D histograms for muons filled during
65 Monte Carlo simulation, which are mana 65 Monte Carlo simulation, which are managed by the HistoManager class
66 and its Messenger: 66 and its Messenger:
67 67
68 1 Relative muon transferred energy dis 68 1 Relative muon transferred energy distribution
69 (log10(eps/Emu kin) for knock-on e 69 (log10(eps/Emu kin) for knock-on electrons (ionization)
70 2 -"- direct (e+,e-) pair production 70 2 -"- direct (e+,e-) pair production by muons
71 3 -"- bremsstrahlung by muons 71 3 -"- bremsstrahlung by muons
72 4 -"- nuclear interaction by muons 72 4 -"- nuclear interaction by muons
73 5 ionistion for hadrons 73 5 ionistion for hadrons
74 6 (e+,e-) pair production by hadrons 74 6 (e+,e-) pair production by hadrons
75 7 bremsstrahlung by hadrons 75 7 bremsstrahlung by hadrons
76 8 direct mu+,mu- pair production by muons 76 8 direct mu+,mu- pair production by muons
77 77
78 The histos can be activated individually wit 78 The histos can be activated individually with the command :
79 /testem/histo/setHisto id nbBins valMin val 79 /testem/histo/setHisto id nbBins valMin valMax :
80 min and max values of log10(eps/Emu 80 min and max values of log10(eps/Emu kin).
81 81
82 At EndOfRun the corresponding histos for ana 82 At EndOfRun the corresponding histos for analytic calculations are
83 automatically created and filled (histo 11 t 83 automatically created and filled (histo 11 to 14, and 18).
84 84
85 One can control the name and the type of the 85 One can control the name and the type of the histograms file with
86 the command: 86 the command:
87 /testem/histo/setFileName name (default te 87 /testem/histo/setFileName name (default testem17)
88 88
89 6- VISUALIZATION 89 6- VISUALIZATION
90 90
91 The Visualization Manager is set in the main 91 The Visualization Manager is set in the main().
92 The initialisation of the drawing is done vi 92 The initialisation of the drawing is done via the commands
93 /vis/... in the macro vis.mac. To get visual 93 /vis/... in the macro vis.mac. To get visualisation:
94 > /control/execute vis.mac 94 > /control/execute vis.mac
95 95
96 The detector has a default view which is a l 96 The detector has a default view which is a longitudinal view of the
97 box. 97 box.
98 98
99 The tracks are drawn at the end of event, an 99 The tracks are drawn at the end of event, and erased at the end of run.
100 100
101 7- HOW TO START ? 101 7- HOW TO START ?
102 102
103 execute TestEm17 in 'batch' mode from macro 103 execute TestEm17 in 'batch' mode from macro files :
104 % TestEm17 allproc.mac 104 % TestEm17 allproc.mac
105 105
106 execute TestEm17 in 'interactive mode' with 106 execute TestEm17 in 'interactive mode' with visualization :
107 % TestEm17 107 % TestEm17
108 Idle> control/execute vis.mac 108 Idle> control/execute vis.mac
109 .... 109 ....
110 Idle> type your commands 110 Idle> type your commands
111 .... 111 ....
112 Idle> exit 112 Idle> exit