Monte Carlo calculations of the efficiencies and the parasitic pulses for a system of spherical sources and a 3″×3″ NaI(Tl) detector

Optimal design of radioactive particle tracking experiments for flow mapping in opaque multiphase reactors

In the past decade, radioactive particle tracking techniques have emerged in the field of chemical engineering and have become increasingly popular for non-invasive flow mapping of the hydrodynamics in multiphase reactors. Based on gamma-ray sensitization of an array of scintillation detectors, the Computer Automated Radioactive Particle Tracking (CARPT) technique measures flow fields by monitoring the actual motion path of a single discrete radioactive flow follower which has the physical properties of the phase whose motion is being followed. A limitation to the accuracy of CARPT lies in the error associated with the reconstruction of the tracer particle position which affects the space-resolution capability of the technique. It is of interest, therefore, to minimize this error by choosing wisely the best hardware and an optimal configuration of CARPT detectors' array. Such choices are currently based on experience, without firm scientific basis. In this paper, through theoretical modeling and simulation, we describe how the accuracy of a radioactive particle tracking setup may be assessed a priori. Through an example of a proposed implementation of CARPT on a gas-solids riser, we demonstrate how this knowledge can be used for choosing the hardware required for the experiment. Finally, we show how the optimal arrangement of detectors can be effected for maximum accuracy for a given amount of monetary investment for the experiment.