Timing Resolution Study of an Associated Particle Detector for Fast Neutron Imaging

D-T neutron generators have been used as an active interrogation source for associated particle imaging techniques. The D-T reaction yields a 14-MeV neutron and an alpha particle. The kinetics of the reaction allow the directionality and timing of the neutron to be determined utilizing position sensitive detectors for both the alpha and neutron. This information may be used for imaging applications. Since position and timing are required to form images, improved certainty in directional and timing will result in improved imaging performance. This requires maximum light transmission from its origin in the scintillator to conversion at the photosensor. This work is a study of the timing resolution of a first generation associated particle detector. An optical transport code, coupled with a timing model is also used to simulate the timing resolution. Good agreement is shown. Fundamental limits are presented with the aid of simulation and measurements. Based on these results, implications on the next-generation design are discussed.