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 		  Geant4 - spower example
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                                README file
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                           CORRESPONDING AUTHOR

S. Incerti et al. (a, *)
a. LP2i, IN2P3 / CNRS / Bordeaux University, 33175 Gradignan, France
* e-mail: incerti@lp2ib.in2p3.fr

---->0. 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:
Med. Phys. 51 (2024) 5873–5889
Med. Phys. 45 (2018) e722-e739
Phys. Med. 31 (2015) 861-874
Med. Phys. 37 (2010) 4692-4708
Int. J. Model. Simul. Sci. Comput. 1 (2010) 157–178

and for this example:
Nucl. Instrum. Meth. B 397 (2017) 45-50

---->1. 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.

---->2. 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.

---->3. 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.

---->4. 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.

---->5. 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.
