A simulation study on spatial and time resolution for a cost-effective positron emission particle tracking system

Abstract

This work is the second part of a simulation study investigating the processing of densely packed and moving granular assemblies by positron emission particle tracking (PEPT). Since medical positron emission tomography (PET) scanners commonly used for PEPT are very expensive, a PET-like detector system based on cost-effective organic plastic scintillator bars is being developed and tested for its capabilities. In this context, the spatial resolution of a resting positron source, a source moving on a freely designed model path, and a particle motion given by a discrete element method (DEM) simulation is studied using Monte Carlo simulations and the software toolkit Geant4. This not only extended the simulation and reconstruction to a moving source but also significantly improved the spatial resolution compared to previous work by adding oversampling and iteration to the reconstruction algorithm. Furthermore, in the case of a source following a trajectory developed from DEM simulations, a very good resolution of about 1 mm in all three directions and an average 3D deviation between simulated and reconstructed events of 2.3 mm could be determined. Thus, the resolution for realistic particle motion within the generic grate system (which is the test rig for further experimental studies) is well below the smallest particle size. The simulation of the dependence of the reconstruction accuracy on tracer particle location revealed a nearly constant efficiency within the entire detector system, which demonstrates that boundary effects can be neglected.