Improving precision of DOI-location estimations by photopeak-index method

A photopeak-index method is introduced to improve the accuracy and precision of event-location estimations of the ends-read, edge-on imaging detector, which offers a DOI solution. The corresponding results of the early work on an ends-read, edge-on imaging detector unit showed poor precision for the estimations of event locations along the long axis of crystals. With applying the photopeak-index method, the events with energies close to their photopeak centers were kept for determination of gamma-crystal-interaction locations. The results show that with implement of the photopeak-index filter, the error of event-location estimation on the long axis is significantly improved (from an average 25.6 mm to 15.5 mm), however still not good enough for practical use. By analyzing the experimental data, the poor energy resolutions (19~36%) are understood to be an essential factor leading the poor precisions of estimations. Applying the photopeak-index method with narrower energy window to an ends-read edge-on imaging detector composed of better scintillation materials (such as LaBr₃) and proper surface treatments for crystals, to gain an improved energy resolution, might make the design more practicable.