Implementing the Independent Reaction Time method in Geant4 for radiation chemistry simulations

The Independent Reaction Time method is a computationally efficient Monte-Carlo based approach to simulate the evolution of initially heterogeneously distributed reaction-diffusion systems that has seen wide-scale implementation in the field of radiation chemistry modeling. The method gains its efficiency by preventing multiple calculations steps before a reaction can take place. In this work we outline the development and implementation of this method in the Geant4 toolkit to model ionizing radiation induced chemical species in liquid water. The accuracy and validity of these developed chemical models in Geant4 is verified against analytical solutions of well stirred bimolecular systems confined in a fully reflective box.