A 40-channel readout ASIC for ToF-PET

Future semiconductor based PET detectors will increase the number of channels by about two orders of magnitude compared to current systems. Highly integrated readout electronics measuring all the PET relevant parameters, like position, energy and timing of a gamma-event are thus required. A 40 channel prototype ASIC has been designed, built and characterized. This design contains for each channel a fast discriminator, a high accuracy time stamping unit, a precise, linear charge integrator and an ADC. The design features a low trigger threshold, variable integration time and a fair power consumption. A low deadtime enables the processing of high hit rates, while an intrinsic timing resolution better than 30 ps rms. allows for effective use in ToF systems.