Fig. 3

A schematic of the principles of PEPT using the Philips ADAC Forte dual-headed positron detector: the intersection of LORs are used to determine the position of the positron-emitting tracer in a dense granular system, such as a rotating drum. This figure is adapted from Windows-Yule et al., Annual Review of Chemical and Biomolecular Engineering, Vol 11, Positron Emission Particle Tracking of Granular Flows, Copyright Annual Reviews (2020)16, CC BY open access license.