Adopting new technologies in the LHCb Gauss simulation framework

The increase in luminosity foreseen in the future years of operation of the Large Hadron Collider (LHC) creates new challenges in computing efficiency for all participating experiment. For Run 3 of the LHC, the LHCb collaboration needs to simulate about two orders of magnitude more Monte Carlo events to exploit the increased luminosity and trigger rate. Therefore, the LHCb simulation framework (Gauss) will go through a significant renovation, mostly driven by the upgraded core software framework (Gaudi) and the availability of a multithreaded version of Geant4. The upgraded Gaudi framework replaces single-threaded processing by a multithreaded approach, allowing concurrent execution of tasks with a single event as well as multiple events in parallel. A major task of the required overhaul of Gauss is the implementation of a new interface to the multithreaded version of Geant4.