BASIC32_ADC, a front-end ASIC for SiPM detectors

BASIC32_ADC is the last version of a family of multichannel ASICs developed to read-out Silicon Photo-Multiplier detectors in medical imaging applications. With respect to the previous realizations, modifications of the analog channel structure and a different overall organization of the ASIC architecture have been adopted to solve problems which could arise when a continuous slab of scintillating crystal is read out by an array of photodetectors to extract the Depth Of Interaction (DOI) information. In fact, in this case, the detectors peripheral with respect to the center of interaction will receive a small amount of photons which do not pile up in effective way, thus producing probably a current pulse smaller than the threshold set to cut off the dark pulses. As a consequence, the related channels can be ignored in a sparse read-out acquisition, even though they are associated to a significant amount of charge. The self-triggered ASIC features 32 read-out channels, exhibits improved configuration flexibility and includes an 8-bit, two step subranging ADC. In this work we report on the design and the first characterization results of the ASIC.