Evaluation of a multi-module demonstrator for the ITk Pixel Outer Barrel for the ATLAS Phase-II upgrade

The ATLAS tracking system will be replaced by an all-silicon detector for the HL-LHC upgrade around 2025. The innermost five layers of the detector system will be pixel detector layers which will be most challenging in terms of radiation hardness, data rate and readout speed. A serial power scheme will be used for the pixel layers to reduce the radiation length and power consumption in cables. New elements are required to operate and monitor a serially powered detector including a detector control system, constant current sources and front-end electronics with shunt regulators. A demonstrator prototype was built using about 40 FE-I4 modules powered in six serial chains, that employs realistic mechanics and services, interlock and cooling infrastructure, power supplies and readout system. In the presentation, the latest results and full evaluation of the electrical prototype are presented. Important qualification steps of the system design and its operation are discussed.