Silicon sensors for the Phase-2 upgrade of the CMS Outer Tracker; status and early results from the production phase

Abstract

The high luminosity upgrade of the Large Hadron Collider (HL-LHC) will set new challenges in the operation and performance of the CMS and ATLAS experiments. The peak luminosity of the HL-LHC machine will reach 5 - 7.5 ×1034 cm−2 s−1, which will deliver to the experiments a 10-fold increase in integrated luminosity by the end of its lifetime. The CMS Tracker will have to be fully replaced in order to maintain its excellent performance and to withstand this more demanding environment. The upgraded system is divided into an Outer Tracker, instrumented by short strips and macro-pixels, and a high granularity Inner Tracker using pixels. After several years of research on different sensor options, the baseline for the Outer Tracker sensors has been defined and production of over 24,000 sensors started in 2020. This report will provide a brief overview of the new Outer Tracker silicon sensor features, as well as some initial results regarding the quality of the sensors produced to date.