Radiation-Hard Silicon Strip Sensors for the ATLAS Phase-2 Upgrade

Abstract

The ATLAS upgrade for HL-LHC operation includes the installation of an entirely new all-silicon Inner Tracker (ITk). The silicon strip region comprises 165 m 2 of instrumented area, made possible by mass production of silicon strip sensors. This area is covered in a nearly hermetic way. Multiple sensor shapes are utilized: square sensors in the barrel part, and skewed trapezoidal sensors with curved edges to provide a continuous coverage of the disc surface in the endcap part of a detector. As a result, there are 8 different strip sensor types in the system. They all feature AC-coupled n +-in-p strips with polysilicon biasing, developed to withstand the total fluence of 1.6 • 10 15 n eq /cm 2 and the total ionizing dose of 66 Mrad. Following many years of R&D and 4 prototype submissions and evaluations, the project transitioned into pre-production, where 5 % of the total volume is produced in all 8 designs. In this contribution we will summarize the results obtained for the latest prototype sensors ATLAS17LS, a long-strip type sensor for the barrel part, the properties of which are expected to be comparable with the pre-production sensors.