A Dedicated ASIC Front-End Readout for the Monolithic Detector Blocks of the BrainPET Prototype

In this work we present experimental results obtained with a PET prototype module based on monolithic block detectors of LYSO:Ce coupled to 2 Hamamatsu S8550-02 APD arrays and a dedicated ASIC front end readout. This module has been designed to be compatible with strong magnetic fields and will be used on a research prototype for PET/MRI human brain imaging. The front-end electronics presented is based on a new ASIC: the VATA240. This ASIC implements the sum of the signals provided by the 8 pixels of each column and row of the detector array. composed of two APD modules. Using these 16 summed channels instead of the output of the 64 single pixels, the signal to noise ratio of the overall detector response is enhanced. To estimate the impinging photon direction we use Neural Networks (NN). The use of the summed channels also reduces the complexity or the NN algorithms implemented. The characterization or the VATA240 ASIC and the adjustment of key parameters, have been carried out, and both the spatial and energy resolution with an electronically-collimated Na-22 radioactive source have been experimentally evaluated.