Speaker
Description
The ATLAS High Granularity Timing Detector (HGTD) is a new detector subsystem that will instrument the ATLAS experiment for the High-Luminosity LHC (HL-LHC) phase in order to preserve the experiment reconstruction performance (and hence its physics potential) under the very high pileup (200 simultaneous proton-proton collisions at every 25ns) arising from the $7.5 \times 10^{34} \mathrm{cm}^{−2} \mathrm {s}^{−1}$ instantaneous luminosity expected during the HL-LHC operation. In order to enhance the sensitivity to physics process in the forward region, ATLAS will extend the rapidity coverage of its tracking system to |η| >4 through a new semiconductor tracking detector (ITk). However, separating the hard scatter from the pile-up requires a spatial resolution impossible to be attained at rapidities above |η| > 2.4 by ITk. By covering the rapidity range 2.4 < |η| <4 with 4 layers of Low-Gain Avalanche Diodes (LGAD), the HGTD will provide timing information with tens of picoseconds resolution and, through the use of a 4D-tracking approach, mitigate the effects of pile-up combining HGTD timing with ITk spatial information. The HGTD consists of two disks of 2 m diameter, symmetrically installed wrt the collision point. Around 3.6 million channels will be readout, covering an area of 6.4 m2 of LGAD sensors. This presentation will discuss the extensive research and development efforts undertaken by the HGTD project, including the design and characterization of the all new LGADs, demonstrating their timing performance and radiation hardness using high-energy particle beams, the development of a custom integrated readout circuit capable of precise time measurements and the integration of these components that encompass the HGTD system.
