Initial testing of singles processing unit for the small animal PET

Small animal Positron Emission Tomography (PET) is a high resolution and sensitivity type of PET device dedicated to imaging small animals. To obtain the position and energy information for the small animal PET, a 32-channel high-resolution time and charge measurement module, named Singles Processing Unit (SPU), is designed. In the SPU, time measurement is achieved based on amplification, summation, leading-edge discrimination and Time-to-Digital Conversion (TDC), while charge measurement is based on amplification, shaping, Analog-to-Digital Conversion (A/D Conversion), and area calculation of signal waveform. To evaluate the functionality and performance of the SPU, we conducted a series of initial tests on the electronics. Test results indicate that the SPU functions well, and the time precision of the SPU is better than 300 ps Full Width Half Maximum (FWHM), while the charge precision is better than 0.3% FWHM. These performances satisfy the application requirements.