Radiation resistant innovative 3D pixel sensors for the CMS upgrade at the High Luminosity LHC

• DOI: 10.1016/j.nima.2020.164429
• Publication Date: 2020-07-18T14:50:07Z
• Authors: M. Meschini; A. Cassese; R. Ceccarelli; L. Viliani; M. Dinardo; S. Gennai; D. Zuolo; A. Messineo; S. Parolia; A. Ebrahimi; D. Pitzl; G. Steinbrück; G.F. Dalla Betta; R. Mendicino; G. Alimonti; C. Gemme; M. Boscardin; S. Ronchin
• Keywords: Upgrade; Radiation hardening

Abstract Results of an extensive R&D program aiming at radiation hard, small pitch, 3D pixel sensors are reported. The CMS experiment is supporting this R&D in the scope of the Inner Tracker upgrade for the High Luminosity phase of the CERN Large Hadron Collider (HL-LHC). In the HL-LHC the Inner Tracker will have to withstand an integrated fluence up to 2 . 3 × 1 0 16 n eq / cm 2 . A small number of 3D sensors were interconnected with the RD53A readout chip, which is the first prototype of 65 nm CMOS pixel readout chip designed for the HL-LHC pixel trackers. In this paper results obtained in beam tests before and after irradiation are reported. The irradiation of a single chip module was performed up to a maximum equivalent fluence of about 1 × 1 0 16 n eq / cm 2 . The analysis of the collected data shows excellent performance: the spatial resolution in not irradiated sensors can reach about 3 to 5 μ m, for inclined tracks, depending on the pixel pitch. The measured hit detection efficiencies are close to 99% measured both before and after the above mentioned irradiation fluence.