Progress on the TRIPOLI-4 - Geant4 coupling

TRIPOLI-4 is a reference Monte-Carlo particle transport code for the simulation of low-energy (≤ 20 MeV) neutron and photon transport and offers a wide range of sophisticated variance-reduction schemes. Geant4 is a particle-transport code which was originally developed as a toolkit for the simulation of the response of LHC detectors and has been constantly extending its application field towards lower particle energies. An attractive aspect of Geant4 is that it offers a wide choice of physics models for the simulation of particle-matter interactions. In this work we explore the possibility to couple TRIPOLI-4 to Geant4 in order to treat applications related to radiation protection, decommissioning around accelerators and high-intensity lasers, and spallation neutron sources. The new capabilities of the coupled code have been illustrated by 3 specific test cases: radiation protection around a high-intensity laser beam, propagation of fast neutrons to a Geant4-modelled detector through severe attenuation, and characterisation of a neutron beam from a spallation source. The coupling allows TRIPOLI-4 to navigate inside Geant4 geometries. Geant4 particle sources can also be imported in TRIPOLI-4. Finally, and most importantly, Geant4 can be used to extend TRIPOLI-4 application scope by adding the capability to transport many additional particles. The coupling is driven from the TRIPOLI-4 side and it is designed in such a way that a TRIPOLI-4 user should be able to run an existing Geant4 calculation through the coupling with minimal additional effort