Giacomo Borghi

FBK and TIFPA

Low Gain Avalanche Diodes – A novel type of silicon detectors for 4-D tracking and x-ray detection

video-meeting,
July 22, 2020; 9:30 AM

ABSTRACT

Low gain avalanche diodes (LGADs) are planar silicon detectors with an internal low-gain multiplication structure (gain ~10). LGADs optimized for timing performances, also called ultra-fast silicon detectors (UFSDs), have recently drawn considerable interest for 4-dimensional tracking applications in high-energy physics (HEP) experiments thanks to their superb timing resolution and radiation hardness. Recently, UFSD sensors developed by FBK, INFN Turin and University of Trento demonstrated the capability to achieve a timing resolution down to ∼30 ps and to be able to withstand the radiation dose expected during the HL-LHC lifetime (> 10¹⁵ n_eq/cm²). Therefore, they are now considered as strong candidates for the timing layer of the future upgrade of both ATLAS and CMS experiments.
Besides timing in HEP experiments, LGADs could potentially replace standard silicon sensors in almost every application, since they can provide larger signals. Therefore, they reduce the noise requirements on the readout electronics or, if electronic performance is kept constant, they enable detectors to be sensitive to much lower signals. For example, LGADs are currently considered a promising option to develop low-energy X-ray (< 1 keV) hybrid detectors for synchrotron applications.
In this seminar, all the developments carried out in FBK in the past years will be summarized and the future roadmap to obtain real 4D-tracking sensors will be presented, focusing in particular on the latest technology variants being currently developed to obtain high spatial resolutions (trench-isolated LGAD, TI-LGAD, and resistive silicon detectors, RSDs).