Intrinsic timing properties of ideal 3D-trench silicon sensor with fast front-end electronics

This paper describes the fundamental timing properties of a single-pixel sensor for charged particle detection based on the 3D-trench silicon structure. We derive the results both analytically and numerically by considering a simple ideal sensor and the corresponding fast front-end electronics in two different case scenarios: ideal integrator and real fast electronics (trans-impedance amplifier). The particular shape of the Time of Arrival (TOA) distribution is examined and the relation between the time resolution and the spread of intrinsic charge collection time is discussed, by varying electronics parameters and discrimination thresholds. The results are obtained with and without simulated electronics noise. We show that the 3D-trench sensors are characterized by a synchronous region, i.e. a portion of the active volume which leads to the same TOA values when charged particles cross it. The synchronous region size is dependent on the front-end electronics and discrimination threshold, and the phenomenon represents an intrinsic physical effect that leads to the excellent time resolution of these sensors. Moreover, we show that the TOA distribution is characterized by an intrinsic asymmetry, due to the 3D geometry only, that becomes negligible in case of significant electronics jitter.