Impact of Position Uncertainty in Stand-Off Imaging

Compact scintillator array-based radiation imaging systems are capable of source localization of special nuclear materials in safeguards and non-proliferation applications. In this paper, we show how spatial resolution affects the accuracy of image reconstruction and we demonstrate how different scintillator surface treatments can reduce position uncertainty. Imaging systems encompassing scintillator arrays typically use a dualended readout, where SiPMs are coupled to both ends of each scintillator, to provide positional information. The dual-ended readout allows for a depth of interaction (DOI) calibration to provide an estimate of the position of interaction. We simulate the effects of position uncertainty on image reconstruction and found a position uncertainty of less than 3 mm is most optimal to maximize the spatial resolution. We then demonstrate how the scintillator surface treatment can affect the position uncertainty, finding average uncertainties of 1.192 mm and 26.096 mm for roughened and polished LYSO crystals, respectively.