Abstract 3D silicon sensors offer excellent radiation hardness and intrinsic time resolution, making them suitable for demanding applications such as those at the High-Luminosity Large Hadron Collider. Columnar electrode pixel detectors are already in use in ATLAS experiment and they are alternative for trench-type sensors which achieve time resolutions near 10 ps, even under extreme irradiation but face fabrication challenges. This study compares the latest 3D silicon sensors developed at Centre Nacional de Microelectrònica (CNM) through the RD50 collaboration, focusing on evaluating how electrode geometry (square vs. hexagonal) affects timing parameters of the signal: Time-of-Arrival (ToA) and Rising Time (RT). Presented results demonstrate Two-Photon Absorption Transient Current Technique (TPA-TCT) as an excellent 3D diagnostic tool for timing non-uniformity caused by electric field inhomogeneity. We present spatially-resolved measurements of ToA and RT as function of bias voltage and laser power across sensor depth.
Laštovička-Medin et al. (Fri,) studied this question.