Performance of liquid Xe PET detector with high quantum efficiency PMT

The liquid Xe as a scintillator has a very fast response. The scintillation light decays with 2.2 ns and 22 ns, and the recombination light for gamma rays decays with 45 ns. Also, the scintillation yield is very high, comparable to that of NaI(Tl) crystals. These properties are considered to be advantageous for application to time of flight-positron emission tomography (TOF-PET). From this perspective, a prototype for a TOF-PET system which consists of two identical liquid xenon detectors has been constructed with new PMTs developed recently with Hamamatsu Photonics and its energy resolution, position resolution and the time resolution were measured. The energy resolutions of 17.9% and position resolutions of 2.1 mm to 3.5 mm were obtained for the detector, respectively, and a time resolution of 260 ps between the two detectors was obtained for 511 keV gamma rays from positron annihilation