source: trunk/examples/extended/radioactivedecay/exrdm/README@ 807

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1
2 =========================================================
3 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
4 =========================================================
5
6 Extended Example for G4RadioactiveDecay
7 --------------------
8
9 The exRDM is created to show how to use the G4RadioactiveDecay process to simulate the decays of radioactive
10 isotopes as well as the induced radioactivity resulted from nuclear interactions. In the example a simple
11 geometry consists of a cylindric target placed in the centre of a tube shaped detector is used. Various primary event
12 generation and tallying options are available. More documentations are available at
13
14 http://reat.space.qinetiq.com/septimess/exrdm
15
16 1. GEOMETRY
17
18 Material: There are 7 pre-defined materials:
19 "Vacuum" "Air" "Silicon" "Aluminium" "Lead" "Germanium" and "CsI"
20
21 User can add a new material at the "PreIni" state, using the command
22 /geometry/material/add
23
24 For the geometry, the world is filled with "Air" and there are two components in it
25
26 - Target: A cylinder placed at the origin along the z-axis. The default size of the cylinder is
27 0.5 cm radius and 1 cm in length, and its default material is "CsI".
28
29 - Detector:A tube cerntred at the origin along the z-axis, with inner radius matching the
30 radius of the target. The default thickness of the tube is 2 cm and it is
31 5 cm long. The default material is "Germanium".
32
33 The user can change the target/detector size and material at the at the "PreIni" state, using the commands under
34
35 /exrdm/det
36
37
38 2. PHYSICS
39
40 The following physics processes are included by default:
41
42 - Standard electromagnetic:
43 photo-electric effect
44 Compton scattering
45 pair production
46 bremsstrahlung
47 ionization
48 multiple scattering
49 annihilation
50
51 - Decay
52
53 - Radioactive Decay
54 By default it is applied through out the geometry. The user can limit it to just the target by
55 commands
56
57 /grdm/noVolumes
58 /grdm/selectVolume Target
59
60
61
62 - Hadronic processes:
63 Hadronic processes are not invoked by default. They can be activated by the user at the "PreIni"
64 state of the execution via the command
65
66 /exrdm/phys/SelectPhysics
67
68 The options are:
69
70 "Hadron" - Physicslist comsists of Binary_Cascade, HP_Neutron, QGSP, and LHEP, or
71 the standdard hadron physics list avaible in the G4 distribution, i.e.
72 "QGSP_BERT", "QGSP_BIC", "QGSP_HP", "LHEP_BERT", "LHEP_BERT_HP", "LHEP_BIC",
73 "LHEP_BIC_HP".
74
75
76 3. EVENT:
77
78 The event generator is based on the G4GeneralParticleSource (GPS) which allows the user to
79 control all aspects of the initial states of the events. In this example, however, only simple features
80 of the GPS are employed to generate the incident beam or the initial radio-isotopes. By default the
81 incident particle is travelling along the + z-axis and the incident position is at the -Z end
82 of the geometry.
83
84 4. DETECTOR RESPONSE:
85
86 No Geant4 HITS and SD are defined in this example. All the relevant information of the simulation is extracted
87 at the "UserSteppingAction" stage, if the variable "G4ANALYSIS_USE" is defined. These include:
88
89 - Emission particles in the RadioactiveDecay process:
90 particle PDGcode,
91 partilce kinetic energy,
92 particle creation time,
93 particle weight.
94
95 Note: the residual nuclei is not considered as an emitted particle.
96
97 - Radio-Isotopes. All the radioactive isotopes produced in the simulation:
98 isotope PDGcode,
99 isotope creation time,
100 isotope weight.
101
102 - Energy depositions in the target and detector by prodicts of the RadioactiveDecay process:
103 energy depostion (positive volue for target and negative for detector),
104 time,
105 weight.
106
107 5. VISUALIZATION:
108
109 Visualisation of the geometry and the tracks is possible with many of the G4 visualisation packages. An
110 example of display the geometry and tracks using VRML is given in the macro file macros/vrml.mac.
111
112 6. ANALYSIS:
113
114 This example implements an AIDA-compliant analysis system as well as the ROOT file format for
115 histograms and ntuples. If the the user has an AIDA-compliant tool such as
116 AIDAJNI, ANAPHE, or PI installed on his/her system, the analysis part of this example can
117 be activated by
118
119 setenv G4ANALYSIS_USE_AIDA 1
120
121 before building the executable. The user can also add the "root" file format option by define
122
123 setenv G4ANALYSIS_USE_RROT 1
124
125 before the compilation.
126
127 At the completion of a simulation run a file "exrdm.root" by default is produced which contains
128 these data structures. The user can change the name of this output file with the command
129
130 /histo/fileName new-filename
131
132 The output file by default is in "root" format and can be analysed offline using the ROOT tool,
133 which allows the histograms and ntuples to examined, manipulated, saved and printed.
134
135 User can also change the output file format to "hbook" or "xml" using the commands
136
137 /histo/fileType hbook
138 /histo/fileType xml
139
140 The output file, in "xml" or "hbook" or "root" format, conatins the 3 ntuples (100,200,300) whose details have been
141 described in section 4. In addition, there are 7 histograms in the file:
142
143 histogram 10: The Pulse Height Spectrum (PHS) of the target.
144 histogram 11: The PHS of the detector.
145 histogram 12: The combined PHS of the target and detector.
146 histogram 13: The anti-coincidece PHS of the target.
147 histogram 14: The anti-coincidece PHS of the detector.
148 histogram 15: The coincidece PHS between the target and detector.
149 histogram 16: The emitted particle energy spectrum.
150
151 The binnings of each histogram can be changed with the command
152
153 /histo/setHisto
154
155 It is assumed the detector and target pulses both have an integration time of 1 micro-second, and the
156 coincidence gate is 2 microsecond wide. The target and detctor have a threshold of 10 keV in the
157 anti-/coincidence modes.
158
159 Histograms 10-15 were derived from the same data stored in ntuple-300(the energy depositions), while
160 Histogram 16 is obtained with data in ntuple-100 (the emission particles). The user should be able to
161 reproduce these histograms, or new histograms, with the ntuple data in an analyis tool such as JAS3.
162
163
164 7. GETTING STARTED:
165
166 i) If you have an AIDA-compliant analysis system installed than you shall switch on the analysis part of
167 example by
168
169 setenv G4ANALYSIS_USE_AIDA 1
170
171 in addition if you want to add the ROOT file format, do
172
173 setenv G4ANALYSIS_USE_ROOT 1
174
175 otherwise make sure the G4ANALYSIS_USE_AIDA and G4ANALYSIS_USE_ROOT are not definded
176
177 unsetenv G4ANALYSIS_USE_AIDA
178 unsetenv G4ANALYSIS_USE_ROOT
179
180 ii) Build the exRDM executable:
181
182 cd to exrdm
183 gmake clean
184 gmake
185
186 gmake will create tmp and bin directories in your $G4TMP and $G4BIN directories.
187 The executable, named exRDM, will be in $G4BIN/$G4SYSTEM/ directory.
188
189 iii) Run the executable: while in the exrdm directory do
190
191 $G4BIN/$G4SYSTEM/exRDM exrdm.in
192
193 If all goes well, the execution shall be terminated in a few seconds. If G4ANALYSIS_USE_ROOT is
194 defined, there will be a proton.root file in the current directory.
195
196 One can use ROOT to exam the file.
197
198 8. FURTHER EXAMPLES:
199
200 There are a number of g4mac files in the ./macros subdirectory, to show the features of the G4RadioactiveDecay
201 process. Most of them will lead to the creation of an aida file in the same name of the micro file, which can
202 be examed and analysed with an analysis tool such as ROOT.
203
204 vrml.mac: to visulise the geometry and the incident of one 100 MeV Cf240 isotope and its decay. A vrml
205 file (g4_xx.vrml) is created at the end. If a default vrml viewer has been set, one shall
206 see the geometru and track displayed automatically.
207
208 u238c.mac: shows the decays of the U238 chain in analogue MC mode.
209
210 th234c-b.mac: shows the decays of Th234 in variance reduction MC mode. All its secondaies in along the
211 decay chains are generated. The default source profile and decay biasing schemes are used
212 to determine the decay times and weights of the secondaries.
213
214 proton-1gev.mac: simulation of 1 GeV protons incident on a lead target. The decays of the radio-siotopes
215 created in the proton-lead interactions are simulated with RadioactiveDecay in analogue
216 MC mode.
217
218 proton-b.mac: same as proton-1geV.mac, but the decays of the radio-siotopes created in the proton-lead
219 interactions are simulated with RadioactiveDecay in variance reduction MC mode. The isotopes
220 and those along the decay chains are forced to decay in the time windows specified by the
221 user in file measures.data, and the weights of the decay products are determined by the
222 beam profile as defined in the beam.data file and their decay times.
223
224 one-iso.mac: simple macro file to show how to simulate the decay of a specific radio-isotope. User can
225 edit it to simulate which ever isotope he/she likes to try.
226
227 neutron.mac: macrofile to show the incident of low energy neutrons on an user specified NaI target and
228 the decays of the induced radio-isotopes. This shows how to define a new material in exrdm.
229
230 ne24.mac: this shows the decays of Ne-24 to Na-24 in variance reduction MC mode. Further decays of Na-24
231 are not simulated by applying the nucleuslimits in RadioactiveDecay. Two runs are carried out.
232 One with the bracjing ratio biasing applied and one without.
233
234 multiple-source.mac: to show the decays of different isotopes uniformly distributed through the target
235 volume in a single run.
236
237 isotopes.mac: to show the decays of a number of different isotopes in a single macro file.
238
239
240 f24.mac: to show the different treatments one can apply to the decays of F24. i) the complete decay chain
241 from F24 to Mg24, in analogue mode; ii) the complete chain, but in variance reduction mode;
242 iii) restrict to the decay of F24 only in analogue mode; iv) restrict to the decay of F24 only but
243 in variance reduction mode.
244
245 as74.mac: The decays of As74 which has a rather complicated decay scheme. i) in analogue MC mode; ii) in
246 variance reduction MC mode.
247
248 test.mac: macro used to check if the right physics processes are assigned to different particles.
249
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