| Geant4 Cross Reference |
>> 1 $Id: README,v 1.9 2010-04-02 13:22:02 maire Exp $
>> 2 -------------------------------------------------------------------
1 3
2 ========================================= 4 =========================================================
3 Geant4 - an Object-Oriented Toolkit for S 5 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
4 ========================================= 6 =========================================================
5 7
6 Hadr03 8 Hadr03
7 ------ 9 ------
8 10
9 How to compute total cross section from the 11 How to compute total cross section from the direct evaluation of the
10 mean free path ( see below, item Physics). 12 mean free path ( see below, item Physics).
11 How to identify nuclear reactions. 13 How to identify nuclear reactions.
12 How to plot energy spectrum of secondary pa 14 How to plot energy spectrum of secondary particles.
13 15
14 1- GEOMETRY DEFINITION 16 1- GEOMETRY DEFINITION
15 17
16 It is a single box representing a 'semi inf 18 It is a single box representing a 'semi infinite' homogeneous medium.
17 Two parameters define the geometry : 19 Two parameters define the geometry :
18 - the material of the box, 20 - the material of the box,
19 - the (full) size of the box. 21 - the (full) size of the box.
20 22
21 The default geometry (10 m of molybdenum) i 23 The default geometry (10 m of molybdenum) is built in DetectorConstruction,
22 but the above parameters can be changed int 24 but the above parameters can be changed interactively via commands defined
23 in DetectorMessenger. 25 in DetectorMessenger.
24 26
25 2- PHYSICS LIST 27 2- PHYSICS LIST
26 28
27 The PhysicsList contains builders for hadro 29 The PhysicsList contains builders for hadronic interactions.
28 Predefined G4 PhysicsConstructors or 'local 30 Predefined G4 PhysicsConstructors or 'local' PhysicsConstructors can be used
29 (see geant4/source/physics_lists or example 31 (see geant4/source/physics_lists or example runAndEvent/RE04).
30 32
31 In order not to introduce 'artificial' cons 33 In order not to introduce 'artificial' constraints on the step size,
32 electromagnetic processes are not registere 34 electromagnetic processes are not registered: there is no continuous energy
33 loss. 35 loss.
34 <<
35 Several hadronic physics options are contro <<
36 To select them, see Hadr03.cc. <<
37 36
38 3- AN EVENT : THE PRIMARY GENERATOR 37 3- AN EVENT : THE PRIMARY GENERATOR
39 38
40 The primary kinematic consists of a single 39 The primary kinematic consists of a single particle starting at the edge
41 of the box. The type of the particle and it 40 of the box. The type of the particle and its energy are set in
42 PrimaryGeneratorAction (neutron 1 MeV), and 41 PrimaryGeneratorAction (neutron 1 MeV), and can be changed via the G4
43 build-in commands of ParticleGun class (see 42 build-in commands of ParticleGun class (see the macros provided with
44 this example). 43 this example).
45 44
46 4- PHYSICS 45 4- PHYSICS
47 46
48 An event is killed at the first interaction << 47 An event is killed at the first interaction of the incident paticle.
49 The absorption length, also called mean fre 48 The absorption length, also called mean free path, is computed as
50 the mean value of the track length of the i 49 the mean value of the track length of the incident particle.
51 This is why the medium must be 'infinite' : 50 This is why the medium must be 'infinite' : to be sure that interaction
52 occurs at any events. 51 occurs at any events.
53 52
54 The result is compared with the 'input' val 53 The result is compared with the 'input' value, i.e. with the cross sections
55 given by G4HadronicProcessStore and used by 54 given by G4HadronicProcessStore and used by Geant4.
56 55
57 The list of nuclear reactions that occured 56 The list of nuclear reactions that occured is printed.
58 (the number of gamma of deexcitation is not 57 (the number of gamma of deexcitation is not printed).
59 58
60 Then, comes the total list of generated par 59 Then, comes the total list of generated particles and ions.
61 The energy spectrum of the scattered partic 60 The energy spectrum of the scattered particle (if any) and of the created
62 secondaries are plotted (see SteppingAction 61 secondaries are plotted (see SteppingAction).
63 62
64 Momentum conservation is checked as : 63 Momentum conservation is checked as :
65 momentum balance = modulus(P_out - P_in) 64 momentum balance = modulus(P_out - P_in)
66 65
67 A set of macros defining various run condit 66 A set of macros defining various run conditions are provided.
68 The processes can be actived/inactived in o 67 The processes can be actived/inactived in order to survey the processes
69 individually. 68 individually.
70 69
71 5- HISTOGRAMS 70 5- HISTOGRAMS
72 71
73 The test contains 12 built-in 1D histograms 72 The test contains 12 built-in 1D histograms, which are managed by
74 G4AnalysisManager and its Messenger. The hi 73 G4AnalysisManager and its Messenger. The histos can be individually
75 activated with the command : 74 activated with the command :
76 /analysis/h1/set id nbBins valMin valMax u 75 /analysis/h1/set id nbBins valMin valMax unit
77 where unit is the desired unit for the hist 76 where unit is the desired unit for the histo (MeV or keV, etc..)
78 (see the macros xxxx.mac). 77 (see the macros xxxx.mac).
79 78
80 1 "kinetic energy of scattered pri 79 1 "kinetic energy of scattered primary particle"
81 2 "kinetic energy of gamma" << 80 2 "kinetic energy of recoil nuclei"
82 3 "kinetic energy of e-" << 81 3 "kinetic energy of gamma"
83 4 "kinetic energy of neutrons" 82 4 "kinetic energy of neutrons"
84 5 "kinetic energy of protons" 83 5 "kinetic energy of protons"
85 6 "kinetic energy of deuterons" 84 6 "kinetic energy of deuterons"
86 7 "kinetic energy of alphas" 85 7 "kinetic energy of alphas"
87 8 "kinetic energy of nuclei" << 86 8 "kinetic energy of all others ions"
88 9 "kinetic energy of mesons" << 87 9 "kinetic energy of all others mesons"
89 10 "kinetic energy of baryons" << 88 10 "kinetic energy of all others baryons"
90 11 "Q = Ekin out - Ekin in" 89 11 "Q = Ekin out - Ekin in"
91 12 "Pbalance = mag(P_out - P_in)" << 90 12 "Pbalance = mag(P_out - P_in)"
92 13 "atomic mass of nuclei" <<
93 91
94 The histograms are managed by the HistoMana 92 The histograms are managed by the HistoManager class and its Messenger.
95 The histos can be individually activated wi 93 The histos can be individually activated with the command :
96 /analysis/h1/set id nbBins valMin valMax u 94 /analysis/h1/set id nbBins valMin valMax unit
97 where unit is the desired unit for the hist 95 where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
98 96
99 One can control the name of the histograms 97 One can control the name of the histograms file with the command:
100 /analysis/setFileName name (default Hadr0 98 /analysis/setFileName name (default Hadr03)
101 99
102 It is possible to choose the format of the 100 It is possible to choose the format of the histogram file : root (default),
103 xml, csv, by using namespace in HistoManage 101 xml, csv, by using namespace in HistoManager.hh
104 102
105 It is also possible to print selected histo 103 It is also possible to print selected histograms on an ascii file:
106 /analysis/h1/setAscii id 104 /analysis/h1/setAscii id
107 All selected histos will be written on a fi 105 All selected histos will be written on a file name.ascii (default Hadr03)
108 106
109 6- VISUALIZATION 107 6- VISUALIZATION
110 108
111 The Visualization Manager is set in the mai 109 The Visualization Manager is set in the main().
112 The initialisation of the drawing is done v 110 The initialisation of the drawing is done via the commands
113 /vis/... in the macro vis.mac. To get visua 111 /vis/... in the macro vis.mac. To get visualisation:
114 > /control/execute vis.mac 112 > /control/execute vis.mac
115 113
116 The detector has a default view which is a 114 The detector has a default view which is a longitudinal view of the box.
117 The tracks are drawn at the end of event, a 115 The tracks are drawn at the end of event, and erased at the end of run.
118 116
119 7- HOW TO START ? 117 7- HOW TO START ?
120 118
121 Execute Hadr03 in 'batch' mode from macro f 119 Execute Hadr03 in 'batch' mode from macro files :
122 % Hadr03 inelastic.mac 120 % Hadr03 inelastic.mac
123 121
124 Execute Hadr03 in 'interactive mode' with v 122 Execute Hadr03 in 'interactive mode' with visualization :
125 % Hadr03 123 % Hadr03
126 Idle> control/execute vis.mac 124 Idle> control/execute vis.mac
127 .... 125 ....
128 Idle> type your commands 126 Idle> type your commands
129 .... 127 ....
130 Idle> exit 128 Idle> exit
131 << 129
132 Macros provided in this example: <<
133 - hadr03.in: macro used in Geant4 testing <<
134 - Au196.mac: neutron (1 MeV) on Au195 <<
135 - elastic.mac: proton (10 MeV) on Mo100. Ela <<
136 - fusion.mac: deuteron (400 keV) on tritium <<
137 - gamma.mac: gamma (10 MeV) on Au196 <<
138 - inelastic.mac: proton (10 MaV) on Mo98. In <<
139 - ion.mac: Li7 (140 MeV) on Be9 <<
140 - nCapture.mac: neutron (1 eV) on Boron. Cap <<
141 - nFission.mac: neutron (1 eV) on U235. Fis <<
142 - neutron.mac: neutron (1 MeV) on Boron <<
143 <<
144 Macros to be run interactively: <<
145 - debug.mac: proton (10 MeV) on Boron <<
146 - vis.mac: To activate visualization <<