Gabriele Cosmo\page Exampleradial Example radial
\author S. Incerti (a, *)\n a. LP2i, IN2P3 / CNRS / Bordeaux 1 University, 33175 Gradignan, France \n
- e-mail: incerti@lp2ib.in2p3.fr\n
INTRODUCTION
The radial example shows how to simulate radial dose profiles in liquid water from incident ions using the Geant4-DNA physics processes and models.
The Geant4-DNA 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
GEOMETRY SET-UP
The geometry is a set of cylindrical shells (hollow cylinders) made of liquid water (G4_WATER material) and aligned along the Z-axis.
The World is a cylinder wrapping these shells and having the same maximum radius. Its material is water and its length can be made larger than the length of the cylinders using an offset.
a) The maximum radius of the set can be specified using the following UI command:
/radial/setWorldRadius value unit
b) The Z length of the shells can be set using:
/radial/setCylinderLength value unit
c) An offset can be added along Z in front and after the shells using the command:
/radial/setWorldOffsetLength value unit
d) The thickness of each shell can be specified using the command:
/radial/setCylinderThickness value unit
Particles are shot from the center of the entrance surface of the offset space, placed just before the cylinders along the Z axis. The Z position is negative and is equal to the half-length of the World augmented with the offset.
DATA
Make sure $G4LEDATA points to the low-energy electromagnetic data files.
HOW TO RUN THE EXAMPLE
In interactive mode, run:
./radial
In batch, the macro radial.in can be used. It shows how to shoot different types of ions and how to use Geant4-DNA Physics constructors.
PHYSICS
The PhysicsList uses Geant4-DNA Physics constructors.
Geant4-DNA Physics constructors can be selected using the command:
/radial/addPhysics DNA_OptX
where X is 0 to 8 (2, 4 or 6 are recommended).
Comments regarding ions:
-
only the ionisation process is considered, and the radial absorbed dose is obtained considering all energy losses by secondary electrons
-
when the incident particle type is ion (/gun/particle ion), specified with Z and A numbers (/gun/ion A Z), the Rudd ionisation extended model is used. The particles are tracked by default down to 0.5 MeV/u and undergo below a capture process. This tracking cut can be bypassed using:
/radial/addIonsTrackingCut false
SIMULATION OUTPUT
The output results consist in a ROOT radial.root file, containing an ntuple, named "radial" and containing the absorbed dose for each cylinder, identified by its inner radius, per incident ion.
The ROOT macro file plot.C can be used to draw the radial dose profile.