Results of CMS Phase-2 TEPX system tests

Abstract The Compact Muon Solenoid (CMS) detector will undergo a major upgrade (Phase-2) to take advantage of the increased luminosity provided by the High-Luminosity Large Hadron Collider (HL-LHC). As part of this upgrade, the Tracker Endcap Pixel detector (TEPX) will be introduced as a subsystem of the Phase-2 Inner Tracker, extending the pseudorapidity coverage up to |η|< 4. The TEPX system will consist of eight double-layer disks. The goal of the TEPX system tests is to identify and resolve issues related to the operation of 4-chip modules integrated onto the disks, communication quality, and thermal performance before the full subsystem is produced. This will help ensure reliable performance over the expected 10-year operational lifetime. We have found the electrical performance of modules integrated into the serial power chains on the printed circuit board and on the mechanical structures to be compatible with the standalone performance in the quality assurance tests. The system has passed the data transmission quality requirements. An acceptable thermal interface material for the critical interface between the modules and the mechanical structure was identified.