This packages provides tools to run a fast track simulation on top of the core library. The fast track simulation (Fatras) uses the actor plug-in mechanism of the Acts::Propagator and its predictive navigation to simulate particle trajectories through the tracking detector.

As a fast track simulation, it uses the surface-based reconstruction geometry description, i.e. Acts::TrackingGeometry, as a simulation geometry instead of a detailed volumetric description. Interactions and material effects are simulated using parametrized models:

• Multiple Coulomb scattering is simulated by Gaussian (mixture) approximations.
• Ionisation loss is simulated using the Bethe-Bloch formalism.
• Radiation loss is simulated using the Bethe-Heitler formalism.