The main goal of this project is to set up of a “virtual modeling lab” to study radiation effects in both biological matter and materials, in relevant scenarios for space and planetary exploration. This will be done by combining ab-initio electron-ion coupled dynamics for the effects of radiation in matter down to the very molecular and atomistic level via codes such as SIESTA (https://departments.icmab.es/leem/siesta/) and CP2K (https://www.cp2k.org/about) and Monte Carlo particle transport modelling.
Monte Carlo particle transport codes, like Geant4-DNA (a track structure code) for biological matter and Geant4 (a "condensed history" Monte Carlo particle transport code) for high energy impacting particles and mostly solid state targets are very efficient and successfull in many cases. Nonetheless, for biological matter, codes actually follow the track structure essentially in the sole water and then superimpose a coarse grained (geometrical) model of the biological molecules. The estimation of the damage is done via the density of ionization events, which compared to a certain threshold gives an idea of the strand breaks. This leaves high uncertainities, which should be overcome to develop accurate risk models for space radiation effects (and ion-therapy applications). For condensed-history Monte Carlo, the estimation of atomic displacements in target solid state materials is based on relatively crude approximations not valid in the range of biggest damage, like the binary collision approximation, the consideration of a completely amorphous target, the estimation of number of defects often based on a simplied (Kinchin Pease) model.
Ab-initio electron-ion coupled dynamics has the potential to go beyond all these restrictions and approximations, and in principle to strongly ameliorate the damage models for energy regions and lengths scales which are of relevance for bio-molecules and of relevance for particles stopping in active layers of solar cells.
In particular, the work will progress via a series of Work Packages (WPs):
WP1. Space Environment
WP2. Electronic Stopping Power and non-adiabatic effects (electronic excitations) on atomic displacements
WP3: Displacement processes in realistic non-adiabatic conditions
WP4: Stopping power in water, nucleotides, and Geant4-DNA connection studies
WP5: First stage search on more resistant materials
Contact: BIRA-IASB, Av. Circulaire 3, Brussels, Belgium.