Simulation studies on the detection efficiency for a phoswich detector with background rejection capability

Simulation studies were performed on calculation of the detection efficiency for a phoswich detector with background rejection capability for continuous blood sampling system. The detector consists of a plastic scintillator, a BGO scintillator, and a photomultiplier tube (PMT). The pulse shape information is used to distinguish whether the detected event is a true event or a background one. First, we calculated the transmission efficiency of the positron in the tube. And we calculated the detection efficiency of positrons detected by the plastic scintillator. We also calculated the detection efficiency of 511 keV gamma photons by the BGO.