S. Incerti, V. Ivantchenko

Centre d'Etudes Nucléaires de Bordeaux-Gradignan
Université Bordeaux 1
chemin du Solarium
33175 Gradignan


The microdosimetry example illustrates the possibility to combine discrete and condensed history processes in Geant4 at different geometrical scales and in selected regions in a unique Geant4 application, thanks to the common software design adopted by the electromagnetic physics working group of the Geant4 collaboration.

It simulates the track of a 5 MeV proton in liquid water. Geant4 standard EM models are used in the World volume while Geant4-DNA models are used in a Target volume, declared as a Region.

Simulated experimental setup

The geometry is a 1 mm side cube (World) made of liquid water containing a smaller cubic Target volume of liquid water, which dimensions are twenty times smaller than the dimensions of the World volume.


This example shows:
  • how to use the Geant4-DNA processes,
  • how to affect them a name
  • how to combine them with Standard EM Physics.

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 PhysicsList.cc file.

How to install and run the example

Please, look at the README file provided with the example.Simulation results

The output results consists in a microdosimetry.root file (http://root.cern.ch), containing in an ntuple for each simulation step:

  • the type of particle for the current step
  • the type of process for the current step
  • the current preStepPoint (in nanometers)
  • the energy deposit along step
  • the step length

This file can be easily analyzed using for example the provided ROOT macro file plot.C. Example of output results: c1.gif

The naming scheme of particles and processes used is described in SteppingAction.cc.

Suggested papers

See Geant4-DNA publications


Should you have any enquiry, please do not hesitate to contact the author.

-- LucianoPandola - 21 Oct 2014

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