Speaker
Description
The CMS Precision Proton Spectrometer (PPS) was designed for measuring protons that escape along the LHC beam line after the interaction in CMS. It successfully took data during the LHC Run 2, collecting more than 110 fb-1 of integrated luminosity, and since 2022 is taking data in Run 3, having already collected more than 230 fb-1. The PPS tracker was substantially upgraded in preparation for Run 3, with new single-sided 150 um-thick silicon 3D pixel sensors (same design but different pitch as for the inner pixel layers under construction for the ATLAS and CMS trackers for the HL-LHC), read out with the PROC600 chip used in the layer 1 of the CMS pixel tracker after the Phase 1 upgrade. Concerning the mechanics, an innovative solution allowing for vertical movements was adopted to mitigate the radiation effects caused by the non-uniform irradiation of the readout chip, which were the main limiting factors in the Run 2 performance. To adapt the detector to the new 2025-2026 LHC optics with vertical beam crossing in the CMS interaction point, Roman Pots were successfully rotated modifying the acceptance of the detectors. In this contribution we will present the apparatus for Run 3 and the preliminary performance results obtained by analysing the Run 3 data collected up to now.