The ATLAS ITk strip local support structures

A new silicon tracker for the ATLAS detector is envisioned during the Phase-II upgrade of the Large Hadron Collider experiment (LHC), the so-called High Luminosity LHC (HL-LHC). The new Inner Tracker (ITk) consists of a silicon pixel inner tracker and a silicon microstrips outer tracker. This paper focuses on the strips ITk detector, and, in particular, on the high precision, low-mass, high thermo-mechanical performance structures supporting the silicon microstrip modules, so-called "staves" for the barrel region and "petals" for the end-cap regions. A detailed description of these structures is provided, along with the manufacturing procedures employed. This paper covers also the Quality Control (QC) program during pre-production phase, evaluating the mechanical, electrical and thermal performance of twenty support structures of each type, and the validation for their production phase.