A VecGeom navigator plugin for Geant4

Abstract

VecGeom is a geometry modeller library with hit-detection features as needed by particle detector simulation at the LHC and beyond. It was incubated by a Geant-R&D initiative and the motivation to combine the code of Geant4 and ROOT/TGeo into a single, better maintainable piece of software within the EU-AIDA program. So far, VecGeom is mainly used by LHC experiments as a geometry primitive library called from Geant4, where it was shown to provide 7–12% reduction in CPU time due to its faster algorithms for complex primitives [1]. In this contribution, we discuss how VecGeom can be used as the navigating library in Geant4 in order to benefit from both its fast geometry primitives as well as its vectorised navigation module. We investigate whether this integration provides the speed improvements expected, in addition to the gain obtained from geometry primitives. We discuss and benchmark the application of a VecGeomnavigator plugin to Geant4 for a simplified geometry and show paths towards production usage.