| Geant4 Cross Reference |
>> 1 $Id: README 86746 2014-11-17 15:00:13Z gcosmo $
1 ---------------------------------------------- 2 -------------------------------------------------------------------
2 3
3 ========================================= 4 =========================================================
4 Geant4 - an Object-Oriented Toolkit for S 5 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
5 ========================================= 6 =========================================================
6 7
7 TestEm17 8 TestEm17
8 -------- 9 --------
9 This example is intended to check impl 10 This example is intended to check implementation of the processes
10 of muon interactions: ionization, dire << 11 of muon interactions: ionization, direct (e+,e-) production,
11 pair production, bremsstrahlung, and mu-nucl << 12 bremsstrahlung, mu-nuclear interaction.
12 It allows to compute differential cross sect 13 It allows to compute differential cross sections (as function of the
13 energy transfered to secondaries), total cro << 14 energy transfered to secondaries), total cross sections and to compare
14 with analytic calculations. 15 with analytic calculations.
15 16
16 1- GEOMETRY DEFINITION 17 1- GEOMETRY DEFINITION
17 18
18 It is a single box of homogeneous medium. 19 It is a single box of homogeneous medium.
19 Two parameters define the geometry : 20 Two parameters define the geometry :
20 - the material of the box, 21 - the material of the box,
21 - the (full) size of the box. 22 - the (full) size of the box.
22 23
23 The default geometry (1 m of Iron) is constr 24 The default geometry (1 m of Iron) is constructed in
24 DetectorConstruction, but the above paramete 25 DetectorConstruction, but the above parameters can be changed
25 interactively via the commands defined in De 26 interactively via the commands defined in DetectorMessenger.
26 27
27 2- PHYSICS LIST 28 2- PHYSICS LIST
28 29
29 The Physics List of the example uses the mai 30 The Physics List of the example uses the main physics constructor
30 (builder) called "local", which includ << 31 (builder) called "emstandard_opt0". As an alternative "local"
31 processes under study. As an alternati << 32 constructor is provided in which only a limited set
32 and "emstandard_opt4" constructors may << 33 of physics processes are defined for muons, pions and proton:
>> 34 ionisation, bremsstrahlung and e+e- pair production.
33 35
34 Default energy range for EM processes 36 Default energy range for EM processes in this example
35 is from 100*eV to 1000*PeV. 37 is from 100*eV to 1000*PeV.
36 38
37 Optionally "muNucl" builder may be add 39 Optionally "muNucl" builder may be added activating muon-nuclear
38 inelastic interaction. 40 inelastic interaction.
39 41
40 3- AN EVENT : THE PRIMARY GENERATOR 42 3- AN EVENT : THE PRIMARY GENERATOR
41 43
42 The primary kinematic consists of a single p 44 The primary kinematic consists of a single particle starting at the edge
43 of the box. The type of the particle and its 45 of the box. The type of the particle and its energy are set in
44 PrimaryGeneratorAction (mu+ 10 TeV), and can 46 PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
45 build-in commands of ParticleGun class (see 47 build-in commands of ParticleGun class (see the macros provided with
46 this example). 48 this example).
47 49
48 4- PHYSICS 50 4- PHYSICS
49 51
50 The incident particle is a muon. During the 52 The incident particle is a muon. During the tracking, secondary
51 particles are killed. 53 particles are killed.
52 54
53 The number of interactions are plotted as a 55 The number of interactions are plotted as a function of the energy
54 transfered to the secondaries. 56 transfered to the secondaries.
55 The total number of interactions is recorded 57 The total number of interactions is recorded, and the total cross
56 section computed from this. 58 section computed from this.
57 59
58 At RunAction::EndOfRun(..), the above << 60 At EndOfRun, the above results are compared with analytic calculations.
59 calculations. The functions computing << 61 The functions which compute the theoretical cross sections have been
60 provided by the G4 MEPhI group, and implemen << 62 provided by the G4 MEPhI group, and grouped in MuCrossSections class.
61 63
62 5- HISTOGRAMS 64 5- HISTOGRAMS
63 65
64 The test contains built-in 1D histograms for 66 The test contains built-in 1D histograms for muons filled during
65 Monte Carlo simulation, which are mana 67 Monte Carlo simulation, which are managed by the HistoManager class
66 and its Messenger: 68 and its Messenger:
67 69
68 1 Relative muon transferred energy dis 70 1 Relative muon transferred energy distribution
69 (log10(eps/Emu kin) for knock-on e 71 (log10(eps/Emu kin) for knock-on electrons (ionization)
70 2 -"- direct (e+,e-) pair production 72 2 -"- direct (e+,e-) pair production by muons
71 3 -"- bremsstrahlung by muons 73 3 -"- bremsstrahlung by muons
72 4 -"- nuclear interaction by muons 74 4 -"- nuclear interaction by muons
73 5 ionistion for hadrons 75 5 ionistion for hadrons
74 6 (e+,e-) pair production by hadrons 76 6 (e+,e-) pair production by hadrons
75 7 bremsstrahlung by hadrons 77 7 bremsstrahlung by hadrons
76 8 direct mu+,mu- pair production by muons <<
77 78
78 The histos can be activated individually wit 79 The histos can be activated individually with the command :
79 /testem/histo/setHisto id nbBins valMin val 80 /testem/histo/setHisto id nbBins valMin valMax :
80 min and max values of log10(eps/Emu 81 min and max values of log10(eps/Emu kin).
81 82
82 At EndOfRun the corresponding histos for ana 83 At EndOfRun the corresponding histos for analytic calculations are
83 automatically created and filled (histo 11 t << 84 automatically created and filled (histo 11 to 14).
84 85
85 One can control the name and the type of the 86 One can control the name and the type of the histograms file with
86 the command: 87 the command:
87 /testem/histo/setFileName name (default te 88 /testem/histo/setFileName name (default testem17)
88 89
89 6- VISUALIZATION 90 6- VISUALIZATION
90 91
91 The Visualization Manager is set in the main 92 The Visualization Manager is set in the main().
92 The initialisation of the drawing is done vi 93 The initialisation of the drawing is done via the commands
93 /vis/... in the macro vis.mac. To get visual 94 /vis/... in the macro vis.mac. To get visualisation:
94 > /control/execute vis.mac 95 > /control/execute vis.mac
95 96
96 The detector has a default view which is a l 97 The detector has a default view which is a longitudinal view of the
97 box. 98 box.
98 99
99 The tracks are drawn at the end of event, an 100 The tracks are drawn at the end of event, and erased at the end of run.
100 101
101 7- HOW TO START ? 102 7- HOW TO START ?
102 103
103 execute TestEm17 in 'batch' mode from macro 104 execute TestEm17 in 'batch' mode from macro files :
104 % TestEm17 allproc.mac 105 % TestEm17 allproc.mac
105 106
106 execute TestEm17 in 'interactive mode' with 107 execute TestEm17 in 'interactive mode' with visualization :
107 % TestEm17 108 % TestEm17
108 Idle> control/execute vis.mac 109 Idle> control/execute vis.mac
109 .... 110 ....
110 Idle> type your commands 111 Idle> type your commands
111 .... 112 ....
112 Idle> exit 113 Idle> exit