Front-end Electronics Design based on Vernier Method for a High Resolution MicroPET

The design of a high resolution small animal positron emission tomography (MiroPET) camera was presented. This MicroPET has 10 photomultiplier tube (PMT)-Sharing-modular detectors. Each detector has 21 PMTs decoded with 180 BGO(Bi₄Ge₃O_l2 ) crystal elements. A new and low cost design of Time-to- Digital Converter (TDC) based on Vernier method was developed. We use only one FPGA EPF10K30A and achieve 1.3ns timing resolution performance. Such TDC design gives us chance to realize TDC and ADC all together on one Printed Circuit Board (PCB), which would also significantly decrease complication of coincidence processing compared with our previous design. Our preliminary results showed: Vernier TDC had a less than 1.3ns timing resolution that met the demand for coincidence measurement for MicroPET. No inacceptable degradation was observed in time resolution when the temperature changes from 20degC to 40degC We obtain the 16.6% energy resolution, using this new easily compact modular electronic architecture.