POSITRON EMISSION PARTICLE TRACKING - A TECHNIQUE FOR STUDYING FLOW WITHIN ENGINEERING EQUIPMENT

The use of the Birmingham positron camera for tracking positron-emitting particles within engineering structures has been investigated, using particles containing typically 4 MBq (100 muCi) F-18 or Na-22. An algorithm for discarding gamma-ray trajectories corrupted by scattering, etc., and using the remaining trajectories to compute the particle's location in three dimensions has been developed, and its performance explained. A slowly moving particle can be located to within 1 mm several times per second, while a particle moving at 1 ms-1 can be located to within 5 mm 50 times per second, through a considerable thickness of surrounding material. An example of results obtained from tracking a particle in a rotating drum of powder illustrates the potential value of the technique.