Gabriele Cosmo\page Examplespower Example spower
\author S. Incerti et al. (a, *) \n a. LP2i, IN2P3 / CNRS / Bordeaux University, 33175 Gradignan, France \n
- e-mail: incerti@lp2ib.in2p3.fr \n
INTRODUCTION.
The spower example shows how to calculate stopping power of particles in liquid water using the Geant4-DNA physics processes and models.
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: \n Med. Phys. 51 (2024) 5873–5889 \n Med. Phys. 45 (2018) e722-e739 \n Phys. Med. 31 (2015) 861-874 \n Med. Phys. 37 (2010) 4692-4708 \n Int. J. Model. Simul. Sci. Comput. 1 (2010) 157–178
and for this example: \n Nucl. Instrum. Meth. B 397 (2017) 45-50.
GEOMETRY SET-UP
The geometry is a 1 m radius sphere of liquid water (G4_WATER material). Particles are shot randomly from the sphere centre.
Radius of the sphere, physics constructor, primary particle and energy can be controlled by the spower.in macro file.
SET-UP
Make sure G4LEDATA points to the low energy electromagnetic data files.
The code can be compiled with cmake.
It works in MT mode.
HOW TO RUN THE EXAMPLE
In interactive mode, run:
./spower spower.in
The spower.in macro allows a full control of the simulation.
The computation of stopping power is performed in the SteppingAction::UserSteppingAction method.
PHYSICS
Specific physics constructors, called G4EmDNAPhysics_stationary* and adapted from G4EmDNAPhysics* are available to set all inelastic models in a stationary mode for the computation of the stopping power.
SIMULATION OUTPUT AND RESULT ANALYSIS
The accuracy of results may depend on incident statistics as well as on number of steps specified in the SteppingAction::UserSteppingAction method.
The output results consist in a text file (spower.txt), containing :
- energy of incident particles (in eV)
- stopping power (in keV/um)
- rms (i.e. standard deviation) on stopping power (in keV/um)
A ROOT file, spower.root, is also provided for the scoring of secondary electrons. The Geant4 secondary.in example macro can be used to run the corresponding simulation. The plot.C ROOT macro can then be used to display their energy spectrum.