Author: S. Incerti et al. (a, *)
a. Centre d'Etudes Nucleaires de Bordeaux-Gradignan
(CENBG), IN2P3 / CNRS / Bordeaux University, 33175 Gradignan, France
e-mail:incer.nosp@m.ti@c.nosp@m.enbg..nosp@m.in2p.nosp@m.3.fr

INTRODUCTION. <br>

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: Phys. Med. 31 (2015) 861-874 Med. Phys. 37 (2010) 4692-4708

and for this example: 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.

The PrimaryGeneratorAction class is adapted (G4 state dependent) in order to enable generic physics list usage (empty modular physics list).

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 <br>

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 <br>

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)

Should you have any enquiry, please do not hesitate to contact: incer.nosp@m.ti@c.nosp@m.enbg..nosp@m.in2p.nosp@m.3.fr