Efficiency of the Si-strips sensors used in the Precision Proton Spectrometer: radiation damage

The Precision Proton Spectrometer (PPS) is a forward-proton spectrometer using near-beam detectors (inside Roman Pots, RPs) located symmetrically on both sides of IP5 at a distance of about 220 m. In the early stage of the project, the tracking RPs were equipped with the Si-strip sensors used in the TOTEM experiment. Having been conceived for low luminosity and low pileup conditions, these detectors cannot resolve multiple tracks and have low radiation hardness. These constitute the two major sources of inefficiency in high luminosity and high pileup runs. This note describes the method used to evaluate the Si-strip sensor efficiency and the corresponding results for the 2017 data taking.