| 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,
11 pair production, bremsstrahlung, and mu-nucl << 11 bremsstrahlung, 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 "emstandard_opt0". As an alternative "local"
31 processes under study. As an alternati << 31 constructor is provided in which only a limited set
32 and "emstandard_opt4" constructors may << 32 of physics processes are defined for muons, pions and proton:
>> 33 ionisation, bremsstrahlung and e+e- pair production.
33 34
34 Default energy range for EM processes 35 Default energy range for EM processes in this example
35 is from 100*eV to 1000*PeV. 36 is from 100*eV to 1000*PeV.
36 37
37 Optionally "muNucl" builder may be add 38 Optionally "muNucl" builder may be added activating muon-nuclear
38 inelastic interaction. 39 inelastic interaction.
39 40
40 3- AN EVENT : THE PRIMARY GENERATOR 41 3- AN EVENT : THE PRIMARY GENERATOR
41 42
42 The primary kinematic consists of a single p 43 The primary kinematic consists of a single particle starting at the edge
43 of the box. The type of the particle and its 44 of the box. The type of the particle and its energy are set in
44 PrimaryGeneratorAction (mu+ 10 TeV), and can 45 PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
45 build-in commands of ParticleGun class (see 46 build-in commands of ParticleGun class (see the macros provided with
46 this example). 47 this example).
47 48
48 4- PHYSICS 49 4- PHYSICS
49 50
50 The incident particle is a muon. During the 51 The incident particle is a muon. During the tracking, secondary
51 particles are killed. 52 particles are killed.
52 53
53 The number of interactions are plotted as a 54 The number of interactions are plotted as a function of the energy
54 transfered to the secondaries. 55 transfered to the secondaries.
55 The total number of interactions is recorded 56 The total number of interactions is recorded, and the total cross
56 section computed from this. 57 section computed from this.
57 58
58 At RunAction::EndOfRun(..), the above << 59 At EndOfRun, the above results are compared with analytic calculations.
59 calculations. The functions computing << 60 The functions which compute the theoretical cross sections have been
60 provided by the G4 MEPhI group, and implemen << 61 provided by the G4 MEPhI group, and grouped in MuCrossSections class.
61 62
62 5- HISTOGRAMS 63 5- HISTOGRAMS
63 64
64 The test contains built-in 1D histograms for 65 The test contains built-in 1D histograms for muons filled during
65 Monte Carlo simulation, which are mana 66 Monte Carlo simulation, which are managed by the HistoManager class
66 and its Messenger: 67 and its Messenger:
67 68
68 1 Relative muon transferred energy dis 69 1 Relative muon transferred energy distribution
69 (log10(eps/Emu kin) for knock-on e 70 (log10(eps/Emu kin) for knock-on electrons (ionization)
70 2 -"- direct (e+,e-) pair production 71 2 -"- direct (e+,e-) pair production by muons
71 3 -"- bremsstrahlung by muons 72 3 -"- bremsstrahlung by muons
72 4 -"- nuclear interaction by muons 73 4 -"- nuclear interaction by muons
73 5 ionistion for hadrons 74 5 ionistion for hadrons
74 6 (e+,e-) pair production by hadrons 75 6 (e+,e-) pair production by hadrons
75 7 bremsstrahlung by hadrons 76 7 bremsstrahlung by hadrons
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).
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