Speaker
Description
The HL-LHC will provide instantaneous luminosities up to $7.5 \times 10^{34}~$cm$^{−2}$s$^{-1}$, and the increased interaction rate and particle flux will degrade the ATLAS event reconstruction performance. The endcap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has degraded resolution will be particularly affected. A High-Granularity Timing Detector (HGTD) will be installed in front of the LAr endcap calorimeters for pile-up mitigation and luminosity measurements. The HGTD is a novel detector introduced to augment the new all-silicon Inner Tracker in the pseudorapidity range from 2.4 to 4.0, adding the capability to measure charged-particle trajectories in time as well as space. Two double-sided layers of silicon sensors will provide precision timing information for charged particles with a resolution as good as 30 ps per track to help assign each particle to the correct vertex. Readout cells have a size of 1.3 mm $\times$ 1.3 mm, leading to a highly granular detector with ~3.7 million channels. Low-Gain Avalanche Detectors (LGAD) technology has been chosen as it provides enough gain to reach the large signal over noise ratio needed. The requirements and overall specifications of the HGTD will be presented as well as the technical design and the project status. The R&D efforts on the sensors, the readout ASIC, and the other components, supported by laboratory and test beam results, will also be presented.
