Performance of new radiation-tolerant thin planar and 3D columnar n+ on p silicon pixel sensors up to a maximum fluence of ∼5×1015 neq/cm2

Abstract The High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) calls for new high radiation-tolerant solid-state pixel sensors, capable of surviving irradiation fluences up to a few 1 0 16  n eq /cm 2 at ∼ 3  cm from the interaction point. The INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler, is aiming at the development of thin n + on p type pixel sensors to be operated at the HL-LHC. The R&D covers both planar and 3D pixel devices made on substrates obtained by the Direct Wafer Bonding technique. The active thickness of the planar sensors studied in this paper is 100 μ m or 130 μ m , that of 3D sensors 130 μ m . First prototypes of hybrid modules, bump-bonded to the present CMS readout chips (PSI46 digital), have been characterized in beam tests. First results on their performance before and after irradiation up to a maximum fluence of ∼ 5 × 1 0 15  n eq /cm 2 are reported in this article.