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S. Guatelli, M.G Pia, INFN Genova
S. Guatelli
( CERN, INFN Genova )CERN, 13 November 2002
Users Workshop
Where to put analysis in Geant4 Applications
With the help of Geant 4 examples!
Useful links:
http://geant4.web.cern.ch/geant4/G4UsersDocuments/
UsersGuides/ForApplicationDeveloper/html/index.html
http://www.ge.infn.it/geant4/
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S. Guatelli, M.G Pia, INFN Genova
I will show:
1. Which Geant4 User classes are suited for :
Book histograms and ntuplesBook histograms and ntuples
Fill histograms and ntuplesFill histograms and ntuples
Store histograms and ntuple in a file Store histograms and ntuple in a file
2. Examples and results of analysis
in Geant 4 Applications
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Mandatory user classes
Management of Physical Processes
Management of Primary Particles
Management of the Geometry
The user must override their methods to build up a smulation!
The user must override their methods to build up a smulation!
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S. Guatelli, M.G Pia, INFN Genova
Optional User Action
Run Action Run Action
TrackTrack
Stepping ActionStepping Action
Event ActionEvent Action
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S. Guatelli, M.G Pia, INFN Genova
Run ActionA run is a collection of events that share
a common beam and a detector
the detector geometry
the set up of sensitive detectors
the physics processes
Within a run, you should keep unchanged
G4UserRunAction user action : class from which you can derive your own concrete class RunAction
MethodbeginOfRunAction()
invoked at the very end of the beamOn()
endOfRunAction() endOfRunAction()
invoked at the beginning of the beamOn()
What you can do
• set a run identification number
•book histograms
•set run specific conditions of the sensitive detectors
•store/print histograms
•manipulate run summaries
Method What you can do
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S. Guatelli, M.G Pia, INFN Genova
Event actionManagement of the events in terms of
tracks of the particles
hits collections
particle tracking
energy deposit
EndOfEvent Action
Method
Visualisation of
the tracks
Eg. information about
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S. Guatelli, M.G Pia, INFN Genova
Stepping Action
PERFORMANCE TIP !
Avoid stepping action if possible and use hits and tracking action.
G4Step Delta of position / time between Pre and PostStepPoint
Step length
Total energy deposited during the step
information of the final status of a particle after the completion of a step
for example:
transient information of the step
Tracking Action
for example:
Position
kinetic energy
trackID number
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Brachytherapy example: analysis with AIDA
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S. Guatelli, M.G Pia, INFN Genova
How to build the analysis in a
Geant4 Application
1. Management of ntuple and histograms
2. Create the file to store the data
3. Book histos and ntples
From brachytherapy example
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S. Guatelli, M.G Pia, INFN Genova
4. Fill histograms
and ntuples 5. Method Finish()
Close histo and ntuple
Close the file
How to build the analysis in a
Geant4 Application
From brachytherapy example
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S. Guatelli, M.G Pia, INFN Genova
At the beginning At the beginning of the BeamOn()of the BeamOn()
Run Action: Management of the Analysis
At the end of the At the end of the BeamOn()BeamOn()
1.open the file
2.create the ntuple and the histograms Book
Finish 1.close the ntuples and histos
2.close the fileFrom brachytherapy example
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S. Guatelli, M.G Pia, INFN Genova
Information aboutenergy deposit
1. Gets the information about the energy deposit from the Hits Collection
Example 1
In the Event Action
From brachytherapy example
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S. Guatelli, M.G Pia, INFN Genova
Example 1
3. Gets information of:
Energy deposit
Spatial coordinates
4. A histogram and a ntuple are filled with energy deposit
Now everything is ok !
From brachytherapy example
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S. Guatelli, M.G Pia, INFN Genova
Storage of
the energy deposit in a ntuple
you can select the energy deposit in planes and represent them in histograms
Geometric set-up
Brachytherapy example
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Example of a result
Simulation of a radioactive
source
The energy deposit fills a 2Dhistogram … … Elaboration of the data stored
0.16 mGy =100%
Isodose curves
Geometric set-up
From brachytherapy example
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Example 2
Histogram of the initial energy of primary particles
The informationThe information is stored in 1D histois stored in 1D histo
ResultResult
From brachytherapy example
In the Primary Action
Primary particle energyPrimary particle energy
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Example 3
range
1. Particle position when the kinetic energy is zero
3. The information3. The information is stored in 1D histois stored in 1D histo
2. range
e- range test S. Guatelli, V. Ivantchenko
In the Stepping
Action
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ResultResult
Example 3 e- range test
S. Guatelli, V. Ivantchenko
Range