| Geant4 Cross Reference |
1 ---------------------------------------------- 1 -------------------------------------------------------------------
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 TestEm15 7 TestEm15
8 -------- 8 --------
9 9
10 How to compute and plot the final stat 10 How to compute and plot the final state of:
11 - Multiple Scattering 11 - Multiple Scattering
12 - Gamma Conversion 12 - Gamma Conversion
13 considered as an isolated processes, see PHY 13 considered as an isolated processes, see PHYSICS.
14 14
15 For Multiple Scattering, the method is expos 15 For Multiple Scattering, the method is exposed below.
16 16
17 For Gamma Conversion, when G4BetheHeitler5DM 17 For Gamma Conversion, when G4BetheHeitler5DModel Model is used,
18 see README.gamma for Histograms and UI comma 18 see README.gamma for Histograms and UI commands description.
19 19
20 1- GEOMETRY DEFINITION 20 1- GEOMETRY DEFINITION
21 21
22 It is a single box representing a 'sem 22 It is a single box representing a 'semi infinite' homogeneous medium.
23 Two parameters define the geometry: 23 Two parameters define the geometry:
24 - the material of the box, 24 - the material of the box,
25 - the (full) size of the box. 25 - the (full) size of the box.
26 26
27 The default geometry (100 m of water) 27 The default geometry (100 m of water) is constructed in
28 DetectorConstruction, but the above pa 28 DetectorConstruction, but the above parameters can be changed
29 interactively via the commands defined 29 interactively via the commands defined in DetectorMessenger.
30 30
31 2- PHYSICS LIST 31 2- PHYSICS LIST
32 32
33 The physics list contains the standard 33 The physics list contains the standard electromagnetic processes.
34 In order not to introduce 'artificial' 34 In order not to introduce 'artificial' constraints on the step size,
35 there is no limitation from the maximu 35 there is no limitation from the maximum energy lost per step.
36 36
37 3- AN EVENT: THE PRIMARY GENERATOR 37 3- AN EVENT: THE PRIMARY GENERATOR
38 38
39 The primary kinematic consists of a si 39 The primary kinematic consists of a single particle starting at the edge
40 of the box. The type of the particle a 40 of the box. The type of the particle and its energy are set in
41 PrimaryGeneratorAction (1 MeV electron 41 PrimaryGeneratorAction (1 MeV electron), and can be changed via the G4
42 build-in commands of ParticleGun class 42 build-in commands of ParticleGun class (see the macros provided with
43 this example). 43 this example).
44 44
45 4- PHYSICS 45 4- PHYSICS
46 46
47 All discrete processes are inactivated 47 All discrete processes are inactivated (see provided macros),
48 so that Multiple Scattering or Gamma C 48 so that Multiple Scattering or Gamma Conversion is 'forced' to
49 determine the first step of the primar 49 determine the first step of the primary particle.
50 The step size and the final state are 50 The step size and the final state are computed and plotted.
51 Then the event is immediately killed. 51 Then the event is immediately killed.
52 52
53 Multiple Scattering: 53 Multiple Scattering:
54 54
55 The result is compared with the 'input' data 55 The result is compared with the 'input' data, i.e. with the cross
56 sections stored in the PhysicsTables a 56 sections stored in the PhysicsTables and used by Geant4.
57 The stepMax command provides an additi 57 The stepMax command provides an additional control of the step size of
58 the multiple scattering. 58 the multiple scattering.
59 59
60 60
61 5- HISTOGRAMS 61 5- HISTOGRAMS
62 62
63 The test contains 16 built-in 1D histo 63 The test contains 16 built-in 1D histograms, which are managed by
64 G4AnalysisManager and its Messenger. T 64 G4AnalysisManager and its Messenger. The histos can be individually
65 activated with the command: 65 activated with the command:
66 /analysis/h1/set id nbBins valMin val 66 /analysis/h1/set id nbBins valMin valMax unit
67 where unit is the desired unit for the 67 where unit is the desired unit for the histo (MeV or keV, etc..)
68 (see the macros xxxx.mac). 68 (see the macros xxxx.mac).
69 69
70 1 Multiple Scattering. True step 70 1 Multiple Scattering. True step length
71 2 Multiple Scattering. Geom step 71 2 Multiple Scattering. Geom step length
72 3 Multiple Scattering. Ratio geo 72 3 Multiple Scattering. Ratio geomSl/trueSl
73 4 Multiple Scattering. Lateral d 73 4 Multiple Scattering. Lateral displacement: radius
74 5 Multiple Scattering. Lateral d 74 5 Multiple Scattering. Lateral displac: psi_space
75 6 Multiple Scattering. Angular d 75 6 Multiple Scattering. Angular distrib: theta_plane
76 7 Multiple Scattering. Phi-posit 76 7 Multiple Scattering. Phi-position angle
77 8 Multiple Scattering. Phi-direc 77 8 Multiple Scattering. Phi-direction angle
78 9 Multiple Scattering. Correlati 78 9 Multiple Scattering. Correlation: cos(phiPos-phiDir)
79 79
80 10 Gamma Conversion. Open Angle * 80 10 Gamma Conversion. Open Angle * Egamma
81 11 Gamma Conversion. Log10(P reco 81 11 Gamma Conversion. Log10(P recoil)
82 12 Gamma Conversion. Phi P recoil 82 12 Gamma Conversion. Phi P recoil angle
83 13 Gamma Conversion. Phi P plus a 83 13 Gamma Conversion. Phi P plus angle
84 14 Gamma Conversion. 2 * cos(phip 84 14 Gamma Conversion. 2 * cos(phiplus + phiminus) Asymmetry
85 15 Gamma Conversion. E plus / E g 85 15 Gamma Conversion. E plus / E gamma
86 16 Gamma Conversion. Phi of Gamma 86 16 Gamma Conversion. Phi of Gamma Polarization
87 87
88 88
89 The histograms are managed by the HistoMana 89 The histograms are managed by the HistoManager class and its Messenger.
90 The histos can be individually activated wi 90 The histos can be individually activated with the command:
91 /analysis/h1/set id nbBins valMin valMax u 91 /analysis/h1/set id nbBins valMin valMax unit
92 where unit is the desired unit for the hist 92 where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
93 93
94 One can control the name of the histograms 94 One can control the name of the histograms file with the command:
95 /analysis/setFileName name (default teste 95 /analysis/setFileName name (default testem15)
96 96
97 It is possible to choose the format of the 97 It is possible to choose the format of the histogram file : root (default),
98 hdf5, xml, csv, by changing the default fil 98 hdf5, xml, csv, by changing the default file type in HistoManager.cc
99 99
100 It is also possible to print selected histo 100 It is also possible to print selected histograms on an ascii file:
101 /analysis/h1/setAscii id 101 /analysis/h1/setAscii id
102 All selected histos will be written on a fi 102 All selected histos will be written on a file name.ascii (default testem15)
103 103
104 6- VISUALIZATION 104 6- VISUALIZATION
105 105
106 The Visualization Manager is set in th 106 The Visualization Manager is set in the main().
107 The initialization of the drawing is d 107 The initialization of the drawing is done via the commands
108 /vis/... in the macro vis.mac. To get 108 /vis/... in the macro vis.mac. To get visualization:
109 > /control/execute vis.mac 109 > /control/execute vis.mac
110 110
111 The detector has a default view which 111 The detector has a default view which is a longitudinal view of the
112 box. 112 box.
113 113
114 The tracks are drawn at the end of eve 114 The tracks are drawn at the end of event, and erased at the end of run.
115 115
116 7- HOW TO START ? 116 7- HOW TO START ?
117 117
118 execute TestEm15 in 'batch' mode from 118 execute TestEm15 in 'batch' mode from macro files:
119 % TestEm15 compt.mac 119 % TestEm15 compt.mac
120 120
121 execute TestEm15 in 'interactive mode' 121 execute TestEm15 in 'interactive mode' with visualization:
122 % TestEm15 122 % TestEm15
123 Idle> control/execute vis.mac 123 Idle> control/execute vis.mac
124 .... 124 ....
125 Idle> type your commands 125 Idle> type your commands
126 .... 126 ....
127 Idle> exit 127 Idle> exit
128 128
129 8 - MACROS 129 8 - MACROS
130 The examples of macros for Multiple Sca 130 The examples of macros for Multiple Scattering:
131 electron.mac muon.mac proton.mac 131 electron.mac muon.mac proton.mac
132 132
133 The example of Gamma Conversion macro: 133 The example of Gamma Conversion macro:
134 gamma.mac - gamma to e+ e- 134 gamma.mac - gamma to e+ e-
135 gamma2mumu.mac gamma to mu+ mu- 135 gamma2mumu.mac gamma to mu+ mu-