Beyond pile-up limitation in time-correlated single photon counting measurement with high-speed and low-distortion electronics

Time-correlated measurements by means of single photon counting have been historically subject to a speed-distortion tradeoff, mainly due to the so-called pile-up effect. Recently, a new theoretical solution has been proposed showing that such tradeoff can be overcome using a detector dead time matched to the excitation period. This result opens the way to unprecedented speed operation in Time Correlated Single Photon Counting combined with low distortion. To achieve this goal, dedicated electronics has to be designed on purpose. In this paper, we report on the design of the first module that implements the proposed solution. Based on the exploitation of a high-performance Single Photon Avalanche Diode, the module features a fast full-integrated Active Quenching Circuit able to drive the sensor and a dummy cell with a finely tunable dead time as short as 12.5ns, a fully-differential avalanche current readout circuit providing the timing information with a jitter lower than 54ps and the logic circuitry that is needed to prevent distortion at high rates. The timing information is converted by a Fast-TAC providing picosecond timing and high linearity along with a count rate as high as 80Mcps.