Validation of GEANT3 simulation studies with a dual-head PMT ClearPET TM prototype

The ClearPET TM project is proposed by working groups of the Crystal Clear Collaboration (CCC) to develop a 2/sup nd/ generation high performance small animal positron emission tomograph (PET). High sensitivity and high spatial resolution is foreseen for the ClearPET TM camera by using a phoswich arrangement combining mixed lutetium yttrium aluminum perovskite (LuYAP:Ce) and lutetium oxyorthosilicate (LSO) scintillating crystals. Design optimizations for the first photomultiplier tube (PMT) based ClearPET camera are done with a Monte-Carlo simulation package implemented on GEANT3 (CERN, Geneva, Switzerland). A dual-head prototype has been built to test the frontend electronics and was used to validate the implementation of the GEANT3 simulation tool. Multiple simulations were performed following the experimental protocols to measure the intrinsic resolution and the sensitivity profile in axial and radial direction. Including a mean energy resolution of about 27.0% the simulated intrinsic resolution is about (1.41+or-0.11)mm compared to the measured of (1.48+or-0.06)mm. The simulated sensitivity profiles show a mean square deviation of 12.6% in axial direction and 3.6% in radial direction. Satisfactorily these results are representative for all designs and confirm the scanner geometry. (9 refs).