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geant4/examples/extended/radioactivedecay/exrdm/README
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Gabriele Cosmo 75c7fd177d Import Geant4 8.3.0 source tree
2016-06-09 15:07:44 +02:00

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=========================================================
Geant4 - an Object-Oriented Toolkit for Simulation in HEP
=========================================================
Extended Example for G4RadioactiveDecay
--------------------
The exRDM is created to show how to use the G4RadioactiveDecay process to simulate the decays of radioactive
isotopes as well as the induced radioactivity resulted from nuclear interactions. In the example a simple
geometry consists of a cylindric target placed in the centre of a tube shaped detector is used. Various primary event
generation and tallying options are available. More documentations are available at
http://reat.space.qinetiq.com/septimess/exrdm
1. GEOMETRY
Material: There are 7 pre-defined materials:
"Vacuum" "Air" "Silicon" "Aluminium" "Lead" "Germanium" and "CsI"
User can add a new material at the "PreIni" state, using the command
/geometry/material/add
For the geometry, the world is filled with "Air" and there are two components in it
- Target: A cylinder placed at the origin along the z-axis. The default size of the cylinder is
0.5 cm radius and 1 cm in length, and its default material is "CsI".
- Detector:A tube cerntred at the origin along the z-axis, with inner radius matching the
radius of the target. The default thickness of the tube is 2 cm and it is
5 cm long. The default material is "Germanium".
The user can change the target/detector size and material at the at the "PreIni" state, using the commands under
/exrdm/det
2. PHYSICS
The following physics processes are included by default:
- Standard electromagnetic:
photo-electric effect
Compton scattering
pair production
bremsstrahlung
ionization
multiple scattering
annihilation
- Decay
- Radioactive Decay
By default it is applied through out the geometry. The user can limit it to just the target by
commands
/grdm/noVolumes
/grdm/selectVolume Target
- Hadronic processes:
Hadronic processes are not invoked by default. They can be activated by the user at the "PreIni"
state of the execution via the command
/exrdm/phys/SelectPhysics
The options are:
"Hadron" - Physicslist comsists of Binary_Cascade, HP_Neutron, QGSP, and LHEP, or
the standdard hadron physics list avaible in the G4 distribution, i.e.
"QGSP_BERT", "QGSP_BIC", "QGSP_HP", "LHEP_BERT", "LHEP_BERT_HP", "LHEP_BIC",
"LHEP_BIC_HP".
3. EVENT:
The event generator is based on the G4GeneralParticleSource (GPS) which allows the user to
control all aspects of the initial states of the events. In this example, however, only simple features
of the GPS are employed to generate the incident beam or the initial radio-isotopes. By default the
incident particle is travelling along the + z-axis and the incident position is at the -Z end
of the geometry.
4. DETECTOR RESPONSE:
No Geant4 HITS and SD are defined in this example. All the relevant information of the simulation is extracted
at the "UserSteppingAction" stage, if the variable "G4ANALYSIS_USE" is defined. These include:
- Emission particles in the RadioactiveDecay process:
particle PDGcode,
partilce kinetic energy,
particle creation time,
particle weight.
Note: the residual nuclei is not considered as an emitted particle.
- Radio-Isotopes. All the radioactive isotopes produced in the simulation:
isotope PDGcode,
isotope creation time,
isotope weight.
- Energy depositions in the target and detector by prodicts of the RadioactiveDecay process:
energy depostion (positive volue for target and negative for detector),
time,
weight.
5. VISUALIZATION:
Visualisation of the geometry and the tracks is possible with many of the G4 visualisation packages. An
example of display the geometry and tracks using VRML is given in the macro file macros/vrml.mac.
6. ANALYSIS:
This example implements an AIDA-compliant analysis system as well as the ROOT file format for
histograms and ntuples. If the the user has an AIDA-compliant tool such as
AIDAJNI, ANAPHE, or PI installed on his/her system, the analysis part of this example can
be activated by
setenv G4ANALYSIS_USE_AIDA 1
before building the executable. The user can also add the "root" file format option by define
setenv G4ANALYSIS_USE_RROT 1
before the compilation.
At the completion of a simulation run a file "exrdm.root" by default is produced which contains
these data structures. The user can change the name of this output file with the command
/histo/fileName new-filename
The output file by default is in "root" format and can be analysed offline using the ROOT tool,
which allows the histograms and ntuples to examined, manipulated, saved and printed.
User can also change the output file format to "hbook" or "xml" using the commands
/histo/fileType hbook
/histo/fileType xml
The output file, in "xml" or "hbook" or "root" format, conatins the 3 ntuples (100,200,300) whose details have been
described in section 4. In addition, there are 7 histograms in the file:
histogram 10: The Pulse Height Spectrum (PHS) of the target.
histogram 11: The PHS of the detector.
histogram 12: The combined PHS of the target and detector.
histogram 13: The anti-coincidece PHS of the target.
histogram 14: The anti-coincidece PHS of the detector.
histogram 15: The coincidece PHS between the target and detector.
histogram 16: The emitted particle energy spectrum.
The binnings of each histogram can be changed with the command
/histo/setHisto
It is assumed the detector and target pulses both have an integration time of 1 micro-second, and the
coincidence gate is 2 microsecond wide. The target and detctor have a threshold of 10 keV in the
anti-/coincidence modes.
Histograms 10-15 were derived from the same data stored in ntuple-300(the energy depositions), while
Histogram 16 is obtained with data in ntuple-100 (the emission particles). The user should be able to
reproduce these histograms, or new histograms, with the ntuple data in an analyis tool such as JAS3.
7. GETTING STARTED:
i) If you have an AIDA-compliant analysis system installed than you shall switch on the analysis part of
example by
setenv G4ANALYSIS_USE_AIDA 1
in addition if you want to add the ROOT file format, do
setenv G4ANALYSIS_USE_ROOT 1
otherwise make sure the G4ANALYSIS_USE_AIDA and G4ANALYSIS_USE_ROOT are not definded
unsetenv G4ANALYSIS_USE_AIDA
unsetenv G4ANALYSIS_USE_ROOT
ii) Build the exRDM executable:
cd to exrdm
gmake clean
gmake
gmake will create tmp and bin directories in your $G4TMP and $G4BIN directories.
The executable, named exRDM, will be in $G4BIN/$G4SYSTEM/ directory.
iii) Run the executable: while in the exrdm directory do
$G4BIN/$G4SYSTEM/exRDM exrdm.in
If all goes well, the execution shall be terminated in a few seconds. If G4ANALYSIS_USE_ROOT is
defined, there will be a proton.root file in the current directory.
One can use ROOT to exam the file.
8. FURTHER EXAMPLES:
There are a number of g4mac files in the ./macros subdirectory, to show the features of the G4RadioactiveDecay
process. Most of them will lead to the creation of an aida file in the same name of the micro file, which can
be examed and analysed with an analysis tool such as ROOT.
vrml.mac: to visulise the geometry and the incident of one 100 MeV Cf240 isotope and its decay. A vrml
file (g4_xx.vrml) is created at the end. If a default vrml viewer has been set, one shall
see the geometru and track displayed automatically.
u238c.mac: shows the decays of the U238 chain in analogue MC mode.
th234c-b.mac: shows the decays of Th234 in variance reduction MC mode. All its secondaies in along the
decay chains are generated. The default source profile and decay biasing schemes are used
to determine the decay times and weights of the secondaries.
proton-1gev.mac: simulation of 1 GeV protons incident on a lead target. The decays of the radio-siotopes
created in the proton-lead interactions are simulated with RadioactiveDecay in analogue
MC mode.
proton-b.mac: same as proton-1geV.mac, but the decays of the radio-siotopes created in the proton-lead
interactions are simulated with RadioactiveDecay in variance reduction MC mode. The isotopes
and those along the decay chains are forced to decay in the time windows specified by the
user in file measures.data, and the weights of the decay products are determined by the
beam profile as defined in the beam.data file and their decay times.
one-iso.mac: simple macro file to show how to simulate the decay of a specific radio-isotope. User can
edit it to simulate which ever isotope he/she likes to try.
neutron.mac: macrofile to show the incident of low energy neutrons on an user specified NaI target and
the decays of the induced radio-isotopes. This shows how to define a new material in exrdm.
ne24.mac: this shows the decays of Ne-24 to Na-24 in variance reduction MC mode. Further decays of Na-24
are not simulated by applying the nucleuslimits in RadioactiveDecay. Two runs are carried out.
One with the bracjing ratio biasing applied and one without.
multiple-source.mac: to show the decays of different isotopes uniformly distributed through the target
volume in a single run.
isotopes.mac: to show the decays of a number of different isotopes in a single macro file.
f24.mac: to show the different treatments one can apply to the decays of F24. i) the complete decay chain
from F24 to Mg24, in analogue mode; ii) the complete chain, but in variance reduction mode;
iii) restrict to the decay of F24 only in analogue mode; iv) restrict to the decay of F24 only but
in variance reduction mode.
as74.mac: The decays of As74 which has a rather complicated decay scheme. i) in analogue MC mode; ii) in
variance reduction MC mode.
test.mac: macro used to check if the right physics processes are assigned to different particles.
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