| 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 Example B1 7 Example B1
8 ----------- 8 -----------
9 9
10 This example demonstrates a very simple appli 10 This example demonstrates a very simple application where an energy
11 deposit is accounted in user actions and thei 11 deposit is accounted in user actions and their associated objects
12 and a dose in a selected volume is calculated 12 and a dose in a selected volume is calculated.
13 13
14 14
15 1- GEOMETRY DEFINITION 15 1- GEOMETRY DEFINITION
16 16
17 The geometry is constructed in the B1::Dete 17 The geometry is constructed in the B1::DetectorConstruction class.
18 The setup consists of a an envelope of box 18 The setup consists of a an envelope of box shape containing two
19 volumes: a spherical cone and a trapezoid. 19 volumes: a spherical cone and a trapezoid.
20 20
21 In this example we use some common materia 21 In this example we use some common materials materials for medical
22 applications. The envelope is made of water 22 applications. The envelope is made of water and the two inner volumes
23 are made from tissue and bone materials. 23 are made from tissue and bone materials.
24 The materials are created with the help of 24 The materials are created with the help of the G4NistManager class,
25 which allows to build a material from the N 25 which allows to build a material from the NIST database using their
26 names. All available materials can be found 26 names. All available materials can be found in the Geant4 User's Guide
27 for Application Developers, Appendix 10: Ge 27 for Application Developers, Appendix 10: Geant4 Materials Database.
28 28
29 2- PHYSICS LIST 29 2- PHYSICS LIST
30 30
31 The particle's type and the physic processe 31 The particle's type and the physic processes which will be available
32 in this example are set in the QBBC physics 32 in this example are set in the QBBC physics list. This physics list
33 requires data files for electromagnetic and 33 requires data files for electromagnetic and hadronic processes.
34 See more on installation of the datasets in 34 See more on installation of the datasets in Geant4 Installation Guide,
35 Chapter 3.3: Note On Geant4 Datasets: 35 Chapter 3.3: Note On Geant4 Datasets:
36 http://geant4.web.cern.ch/geant4/UserDocume 36 http://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides
37 /In 37 /InstallationGuide/html/ch03s03.html
38 The following datasets: G4LEDATA, G4LEVELGA 38 The following datasets: G4LEDATA, G4LEVELGAMMADATA, G4NEUTRONXSDATA,
39 G4SAIDXSDATA and G4ENSDFSTATEDATA are manda 39 G4SAIDXSDATA and G4ENSDFSTATEDATA are mandatory for this example.
40 40
41 In addition the build-in interactive comman 41 In addition the build-in interactive command:
42 /process/(in)activate processNa 42 /process/(in)activate processName
43 allows to activate/inactivate the processes 43 allows to activate/inactivate the processes one by one.
44 44
45 3- ACTION INITALIZATION 45 3- ACTION INITALIZATION
46 46
47 A newly introduced class, B1::ActionInitial 47 A newly introduced class, B1::ActionInitialization, instantiates and registers
48 to Geant4 kernel all user action classes. 48 to Geant4 kernel all user action classes.
49 49
50 While in sequential mode the action classes 50 While in sequential mode the action classes are instatiated just once,
51 via invoking the method: 51 via invoking the method:
52 B1::ActionInitialization::Build() 52 B1::ActionInitialization::Build()
53 in multi-threading mode the same method is 53 in multi-threading mode the same method is invoked for each thread worker
54 and so all user action classes are defined 54 and so all user action classes are defined thread-local.
55 55
56 A run action class is instantiated both thr 56 A run action class is instantiated both thread-local
57 and global that's why its instance is creat 57 and global that's why its instance is created also in the method
58 B1::ActionInitialization::BuildForMaster 58 B1::ActionInitialization::BuildForMaster()
59 which is invoked only in multi-threading mo 59 which is invoked only in multi-threading mode.
60 60
61 4- PRIMARY GENERATOR 61 4- PRIMARY GENERATOR
62 62
63 The primary generator is defined in the B1: 63 The primary generator is defined in the B1::PrimaryGeneratorAction class.
64 The default kinematics is a 6 MeV gamma, ra 64 The default kinematics is a 6 MeV gamma, randomly distributed in front
65 of the envelope across 80% of the transvers 65 of the envelope across 80% of the transverse (X,Y) envelope size.
66 This default setting can be changed via the 66 This default setting can be changed via the Geant4 built-in commands
67 of the G4ParticleGun class. 67 of the G4ParticleGun class.
68 68
69 5- DETECTOR RESPONSE 69 5- DETECTOR RESPONSE
70 70
71 This example demonstrates a simple scoring 71 This example demonstrates a simple scoring implemented directly
72 in the user action classes. Alternative wa 72 in the user action classes. Alternative ways of scoring via Geant4 classes
73 can be found in the other examples. 73 can be found in the other examples.
74 74
75 The energy deposited is collected step by s 75 The energy deposited is collected step by step for a selected volume
76 in B1::SteppingAction and accumulated event 76 in B1::SteppingAction and accumulated event by event in B1::EventAction.
77 77
78 At end of event, the value acummulated in B 78 At end of event, the value acummulated in B1::EventAction is added in B1::RunAction
79 and summed over the whole run (see B1::Even 79 and summed over the whole run (see B1::EventAction::EndOfevent()).
80 80
81 Total dose deposited is computed at B1::Run 81 Total dose deposited is computed at B1::RunAction::EndOfRunAction(),
82 and printed together with informations abou 82 and printed together with informations about the primary particle.
83 In multi-threading mode the energy accumula 83 In multi-threading mode the energy accumulated in G4Accumulable objects per
84 workers is merged to the master in B1::RunA 84 workers is merged to the master in B1::RunAction::EndOfRunAction() and the final
85 result is printed on the screen. 85 result is printed on the screen.
86 86
87 G4Parameter<G4double> type instead of G4dou 87 G4Parameter<G4double> type instead of G4double type is used for the B1::RunAction
88 data members in order to facilitate merging 88 data members in order to facilitate merging of the values accumulated on workers
89 to the master. Currently the accumulables 89 to the master. Currently the accumulables have to be registered to G4AccumulablesManager
90 and G4AccumulablesManager::Merge() has to b 90 and G4AccumulablesManager::Merge() has to be called from the users code. This is planned
91 to be further simplified with a closer inte 91 to be further simplified with a closer integration of G4Accumulable classes in
92 the Geant4 kernel next year. 92 the Geant4 kernel next year.
93 93
94 An example of creating and computing new un 94 An example of creating and computing new units (e.g., dose) is also shown
95 in the class constructor. 95 in the class constructor.
96 96
97 The following paragraphs are common to all ba 97 The following paragraphs are common to all basic examples
98 98
99 A- VISUALISATION 99 A- VISUALISATION
100 100
101 The visualization manager is set via the G4 101 The visualization manager is set via the G4VisExecutive class
102 in the main() function in exampleB1.cc. 102 in the main() function in exampleB1.cc.
103 The initialisation of the drawing is done v 103 The initialisation of the drawing is done via a set of /vis/ commands
104 in the macro vis.mac. This macro is automat 104 in the macro vis.mac. This macro is automatically read from
105 the main function when the example is used 105 the main function when the example is used in interactive running mode.
106 106
107 By default, vis.mac opens an OpenGL viewer 107 By default, vis.mac opens an OpenGL viewer (/vis/open OGL).
108 The user can change the initial viewer by c 108 The user can change the initial viewer by commenting out this line
109 and instead uncommenting one of the other / 109 and instead uncommenting one of the other /vis/open statements, such as
110 HepRepFile or DAWNFILE (which produce files 110 HepRepFile or DAWNFILE (which produce files that can be viewed with the
111 HepRApp and DAWN viewers, respectively). N 111 HepRApp and DAWN viewers, respectively). Note that one can always
112 open new viewers at any time from the comma 112 open new viewers at any time from the command line. For example, if
113 you already have a view in, say, an OpenGL 113 you already have a view in, say, an OpenGL window with a name
114 "viewer-0", then 114 "viewer-0", then
115 /vis/open DAWNFILE 115 /vis/open DAWNFILE
116 then to get the same view 116 then to get the same view
117 /vis/viewer/copyView viewer-0 117 /vis/viewer/copyView viewer-0
118 or to get the same view *plus* scene-modifi 118 or to get the same view *plus* scene-modifications
119 /vis/viewer/set/all viewer-0 119 /vis/viewer/set/all viewer-0
120 then to see the result 120 then to see the result
121 /vis/viewer/flush 121 /vis/viewer/flush
122 122
123 The DAWNFILE, HepRepFile drivers are always 123 The DAWNFILE, HepRepFile drivers are always available
124 (since they require no external libraries), 124 (since they require no external libraries), but the OGL driver requires
125 that the Geant4 libraries have been built w 125 that the Geant4 libraries have been built with the OpenGL option.
126 126
127 From Release 9.6 the vis.mac macro in examp 127 From Release 9.6 the vis.mac macro in example B1 has additional commands
128 that demonstrate additional functionality o 128 that demonstrate additional functionality of the vis system, such as
129 displaying text, axes, scales, date, logo a 129 displaying text, axes, scales, date, logo and shows how to change
130 viewpoint and style. Consider copying thes 130 viewpoint and style. Consider copying these to other examples or
131 your application. To see even more command 131 your application. To see even more commands use help or
132 ls or browse the available UI commands in t 132 ls or browse the available UI commands in the Application
133 Developers Guide, Section 7.1. 133 Developers Guide, Section 7.1.
134 134
135 For more information on visualization, incl 135 For more information on visualization, including information on how to
136 install and run DAWN, OpenGL and HepRApp, s 136 install and run DAWN, OpenGL and HepRApp, see the visualization tutorials,
137 for example, 137 for example,
138 http://geant4.slac.stanford.edu/Presentatio 138 http://geant4.slac.stanford.edu/Presentations/vis/G4[VIS]Tutorial/G4[VIS]Tutorial.html
139 (where [VIS] can be replaced by DAWN, OpenG 139 (where [VIS] can be replaced by DAWN, OpenGL and HepRApp)
140 140
141 The tracks are automatically drawn at the e 141 The tracks are automatically drawn at the end of each event, accumulated
142 for all events and erased at the beginning 142 for all events and erased at the beginning of the next run.
143 143
144 B- USER INTERFACES 144 B- USER INTERFACES
145 145
146 The user command interface is set via the G 146 The user command interface is set via the G4UIExecutive class
147 in the main() function in exampleB1.cc 147 in the main() function in exampleB1.cc
148 The selection of the user command interface 148 The selection of the user command interface is then done automatically
149 according to the Geant4 configuration or it 149 according to the Geant4 configuration or it can be done explicitly via
150 the third argument of the G4UIExecutive con 150 the third argument of the G4UIExecutive constructor (see exampleB4a.cc).
151 151
152 C- HOW TO RUN 152 C- HOW TO RUN
153 153
154 - Execute exampleB1 in the 'interactive mo 154 - Execute exampleB1 in the 'interactive mode' with visualization:
155 % ./exampleB1 155 % ./exampleB1
156 and type in the commands from run1.mac l 156 and type in the commands from run1.mac line by line:
157 Idle> /control/verbose 2 157 Idle> /control/verbose 2
158 Idle> /tracking/verbose 1 158 Idle> /tracking/verbose 1
159 Idle> /run/beamOn 10 159 Idle> /run/beamOn 10
160 Idle> ... 160 Idle> ...
161 Idle> exit 161 Idle> exit
162 or 162 or
163 Idle> /control/execute run1.mac 163 Idle> /control/execute run1.mac
164 .... 164 ....
165 Idle> exit 165 Idle> exit
166 166
167 - Execute exampleB1 in the 'batch' mode f 167 - Execute exampleB1 in the 'batch' mode from macro files
168 (without visualization) 168 (without visualization)
169 % ./exampleB1 run2.mac 169 % ./exampleB1 run2.mac
170 % ./exampleB1 exampleB1.in > exampleB1 170 % ./exampleB1 exampleB1.in > exampleB1.out
171 171
172 172