1. Hadronic physics validation of Geant4
The study of radiation effects is fundamental to the feasibility of interplanetary missions
Geant4 simulations are the primary tool to evaluate quantitatively the effects of the space radiation environment
Crucial point:
how to model physics interactions?
The Geant4 Toolkit provides many alternative and complementary approaches and models
(e.g. Parameterised and theory driven approaches, Bertini and Binary Cascade models, etc.)
Which model is more suitable?
Are these models reliable?

2. against reliable physics references
Hadronic physics validation of Geant4
Systematic, rigorous, quantitative validation of Geant4 hadronic physics models
As:
Energy spectra
Particle multiplicities
Scattering angles
etc.
Similar approach as in Geant4 electromagnetic physics validation
A systematic, statistically rigorous validation of Geant4 hadronic physics is missing at the present time.
against reliable physics references

3. down to the electronvolt scale
Geant 4 extension
down to the electronvolt scale
Simulation of electromagnetic interactions down to low energies is an important issue for space missions to Mars:
Radiation effects on electronics and science instruments are critical to the successful operation of missions
Possible biological effects of radiation on human tissues can compromise the astronauts’ health and the mission feasibility
Currently, Geant4 provides a specialized package to simulate low energy electromagnetic interactions
Models are based on the assumption that the atoms of the material subject to particle interaction are free
This approximation is no more valid below eV
An extension of Geant4 physics capabilities below this energy range requires a novel modeling approach

4. Geant 4 electromagnetic physics validation
Current models have been extensively validated w.r.t. the NIST database (cross sections and stopping powers)
A rigorous statistical analysis has been performed with the Statistical Toolkit developed in the ESA SEPTIMESS project
Extend rigorous validation of Geant4 for electromagnetic physics models
Below 1 KeV
Over 10/100 GeV (not covered by NIST)
Final state generation (spectra, angular distributions)
Provide guidance to users about the selection of electromagnetic physics models to be instantiated in a Physics List