Development of repeating event rejection logic in the LYSO detector using PMT-Quadrant-Sharing technique

In designs of PET detectors, PMT-Quadrant-Sharing(PQS) technique has some remarkable advantages, such as lower production cost, higher efficiency in packing fraction, uniform signal pulse-heights at the edge of the block and the fewer number of PMTs. But it also brings a problem that the events at the edge of scintillators array would be recorded twice, both in this sector and in the neighboring sector. As a result, there will be a lot of wrong events recorded in the edge of sectors. In this work, we use three different repeating event rejection logics: the position logic, the energy logic and the comprehensive logic. All of the three logics can obviously correct the high count caused by the repeating events at the edge of sectors in the 2DMAPs. Because of noise, the position logic and the energy logic are not good enough. The comprehensive logic makes a correction on the energy logic, to reduce the misjudgments. By comparing the 2DMAPs, we concluded that the result of the comprehensive logic is the best.