I am a PhD candidate at the Max Planck Institute for Nuclear Physics (Heidelberg University) and at the GSI Helmholtz Centre for Heavy Ion Research. The purpose of my project is to follow the effects and fate of harmful radicals or reactive species produced by radiolysis of different radiation qualities in a biological environment, in order to establish a connection between their initial yields and the early biological response. To this aim, an extension of the already existing Monte Carlo track structure code TRAX-CHEM into the "homogeneous” chemical / biochemical stage of radiation damage (up to 1s or longer after the administration of the radiation) is required.