Parallel Chains based Read-out System for a Compton Enhanced 3D PET Scanner

The design of a data acquisition system (DAQ) for a positron emission tomography scanner is reported. The PET system, based on long axially oriented scintillation crystals, read out by hybrid photon detectors (HPD), allows 3D parallax-error free Compton enhanced gamma reconstruction. The DAQ system is composed of several readout cards, each one associated with a module of the PET scanner, and of a main card that controls the whole system. Using fast triggering signals from the silicon sensor backplanes, the main card performs the coincidence analysis and, in case of coincidence, it enables the read-out of the two modules involved. The other modules are left free to perform new acquisitions. This concept based on several independent, events driven and parallel read-out chains, drastically reduces the acquisition dead time. The DAQ system here reported, designed for a two module demonstrator set-up, was developed to study and optimize the essential design parameters