Gabriele Cosmo
101 lines
3.3 KiB
Plaintext
101 lines
3.3 KiB
Plaintext
=================================================================
|
|
Geant4 - splitting
|
|
=================================================================
|
|
|
|
|
|
Authors: J. A. Ramos-Mendez*, B. A. Faddegon
|
|
|
|
Department of Radiation Oncology, University of California San Francisco
|
|
* Corresponding author, email to joserm84@gmail.com
|
|
|
|
This example is provided by the Geant4-DNA collaboration.
|
|
|
|
These processes and models are further described at:
|
|
http://geant4-dna.org
|
|
|
|
Any report or published results obtained using the Geant4-DNA software shall
|
|
cite the following Geant4-DNA collaboration publications:
|
|
Phys. Med. 31 (2015) 861-874
|
|
Med. Phys. 37 (2010) 4692-4708
|
|
|
|
If use this example, please cite
|
|
J Ramos-Mendez, et. Al. Phys. Med. Biol. 62(15), 5908-5925, (2017) DOI: 10.1088/1361-6560/aa7831
|
|
|
|
---> 1. A brief description
|
|
|
|
The splitting example uses variance reduction to improve the computational
|
|
efficiency of calculations of ionization cluster size distributions. Ionization
|
|
events are scored in a nanoscaled cylinder. Ionized electrons generated by
|
|
the first generation of secondary electrons are split, i.e. new clone electrons
|
|
are generated, labeled and propagated. The label is used to classify those
|
|
new particles as if they were produced by independent histories to avoid
|
|
overlapping of tracks at final analysis. The splitting is performed only
|
|
if the ionization event occurred in the cylinder.
|
|
|
|
Geant4-DNA processes are used.
|
|
|
|
The example package contains:
|
|
- source files (src, include)
|
|
- README
|
|
- .in, plot.C and visualization macro files
|
|
|
|
**** 2. Set-up.
|
|
|
|
The geometry is a nanoscaled cylinder centered in the world. The medium is
|
|
water everywhere. The dimensions can be defined with
|
|
/detector/diameter 6 nm
|
|
/detector/length 10 nm
|
|
|
|
User can define the split number (default is 1, i.e. no split)
|
|
with:
|
|
|
|
/vrt/numberOfSplit 10
|
|
|
|
**** 3. How to run the example.
|
|
In interactive mode, run:
|
|
./splitting
|
|
Idle> /control/execute vis.mac
|
|
|
|
In batch mode , run:
|
|
|
|
./splitting run.mac
|
|
|
|
To get visualization, make sure to uncomment the #/control/execute vis.mac line in the macro.
|
|
|
|
**** 4. The physics
|
|
|
|
This example shows:
|
|
- how to use the Geant4-DNA processes,
|
|
- how to implement the splitting via G4WrappedProcess
|
|
- how to set the splitting in specific region
|
|
- how to propagate new track information to secondary particles
|
|
|
|
A simple electron capture process is also provided in order to kill electrons
|
|
below a chosen energy threshold, set in the Physics list.
|
|
|
|
Look at the PhyscisList.cc file.
|
|
|
|
**** 5. Simulation output
|
|
|
|
The output results consists in two histograms in root format
|
|
|
|
- the energy deposit in the cylindrical target
|
|
- the frequency distribution of ionization cluster size
|
|
|
|
NOTE: Every time a value is added to a ROOT histogram, it contributes to the statistics.
|
|
For this example, to correct estimate the uncertainties is recommended to split the simulation into
|
|
several jobs and to calculate the statistics from them: batch mode. Otherwise, the statistical
|
|
uncertainty may be underestimated.
|
|
|
|
**** 6. Contacts
|
|
|
|
If you have any questions or wish to notify of updates and/or modification please contact:
|
|
|
|
J. Ramos-Mendez at joserm84@gmail.com
|
|
|
|
**** Acknowledgments :
|
|
|
|
Sebastien Incerti (CNRS) for its guidance
|
|
|
|
|