Reading device and method for measuring energy and flight time using silicon photomultipliers

A readout apparatus for time-of-flight and energy measurements, providing accurate time-of-flight information when used in PET systems with fast crystals, which allow to confine the origin of the two 511 key photons with a position uncertainty of 30 mm along the line-of-response (LOR), characterized by including:

• a silicon photomultiplier (SiPM) per channel;
• front-end conditioning circuits and two analogue time-to-digital converters (TDCs) based on time interpolation, per channel, where the said input front-end circuits and TDCs have power consumption smaller than 10 mW per channel, for use in Time-of-Flight (ToF) Positron Emission Tomography (PET) systems.
• where the said front-end conditioning circuits are low impedance input differential amplifiers built-up by a regulated-gate cascode circuit with low-noise and high bandwidth, and with the ability to fine tune the DC node voltage at the input,
• a dual-threshold mechanism based on two independent branches with trigger thresholds that can be set separately, such that a very low threshold generates a trigger on the first photo-electron, which is used for time measurement, and a higher threshold is used to validate or to discard the input pulse.