Abstract
An analogue CMOS front-end for triggering and amplification of signals produced by a silicon photomultiplier (SiPM) coupled to a LYSO scintillator is proposed. The solution is intended for time-of-flight measurement in compact Positron Emission Tomography (TOF-PET) medical imaging equipments where excellent timing resolution is required ( ≈ 100ps ). A CMOS 0.13μm technology was used to implement such front end, and the design includes preamplification, shaping, baseline holder and biasing circuitry, for a total silicon area of 500x90 μm . Waveform sampling and time-over-threshold (ToT) techniques are under study and the front-end provides fast and shaped outputs for time and energy measurements. Post layout simulation results show that, for the trigger of a single photoelectron, the time jitter due to the pre-amplifier noise can be as low as 15 ps (FWHM), for a photodetector with a total capacitance of 70 pF. The very low input impedance of the pre-amplifier ( ≈ 5Ω ) allows 1.8 ns of peaking time, at the cost of 10 mW of power consumption.