One of the great challenges in the next generation of experiments at the future high-luminosity particle colliders will be the event reconstruction, as the large number of interactions occurring at each bunch crossing will create very large occupancies in the innermost detectors. In many of the studies performed for their upgrades, LHC experiments have showed that the addition of track timing measurements with an accuracy of the order of tens of picoseconds per track will restore tracking and vertexing capabilities at the levels we have today. In the last three years the TimeSPOT Collaboration has developed innovative silicon pixels allowing to reach a time resolution better than 20~ps on minimum ionizing particles. This new devices are 3D silicon pixels with trench electrodes, and they achieve such an outstanding time resolution thanks to both a highly uniform electric field inside the pixel and electrons/holes drift velocities close to saturation. Many different types of sensors, with pixel sizes ranging from 27.5 µm x 27.5 µm to 110 µm x 110 µm and arranged in matrices, multi-pixel strips or single-pixel test structures were produced in two batches in 2019 and 2020 by FBK in Trento, Italy. In a first beam test performed at the PSI πM1 beam-line in October 2019, time resolutions of about 20 ps per hit have been measured. In the last year accurate laboratory tests, both with a pulsed laser-based setup, able to precisely measure the sensor response throughout its active area, and with radioactive sources, emulating a test beam setup in the more controlled laboratory environment, have shown that these 3D pixel sensors intrinsically possess a time resolution close to 10 ps, and presently available front-end electronics represents a limit to their performances. The status of this developments and an outlook of future activities, will be presented at the Conference.
|Collaboration / Activity||TimeSPOT|