Thin n-in-p planar pixel sensors and active edge sensors for the ATLAS upgrade at HL-LHC

Abstract

Silicon pixel modules employing n-in-p planar sensors with an active thickness of 200 µm, produced at CiS, and 100-200 µm thin active/slim edge sensor devices, produced at VTT in Finland have been interconnected to ATLAS FE-I3 and FE-I4 read-out chips. The thin sensors are designed for high energy physics collider experiments to ensure radiation hardness at high fluences. Moreover, the active edge technology of the VTT production maximizes the sensitive region of the assembly, allowing for a reduced overlap of the modules in the pixel layer close to the beam pipe. The CiS production includes also four chip sensors according to the module geometry planned for the outer layers of the upgraded ATLAS pixel detector to be operated at the HL-LHC. The modules have been characterized using radioactive sources in the laboratory and with high precision measurements at beam tests to investigate the hit efficiency and charge collection properties at different bias voltages and particle incidence angles. The performance of the different sensor thicknesses and edge designs are compared before and after irradiation up to a fluence of 1.4×10 16 n eq /cm 2 .

Silicon sensors for trackers at high-luminosity environment

“…The collected charge as a function of the bias voltage for different thicknesses and 800 MeV proton irradiation fluences. At the highest fluence of 14 × 10 15 neqcm −2 the collected charge of the 200 µm thick sensors is slightly higher than for the 300 µm thick, but still compatible within the estimated uncertainties[32].…”

Edgeless and Slim-edge Detectors

“…Recent results have been shown by A Terzo et al [9] with active/slim edge devices interconnected to both ATLAS FE-I3 and FE-I4 devices.…”

Characterisation of irradiated thin silicon sensors for the CMS phase II pixel upgrade

“…This could be the result of the different annealing states of the sensors due to the different amounts of time necessary to accumulate the fluence during irradiation. An improvement in the charge collection after annealing was observed for thin sensors produced on float zone silicon [28]. The 100 µm thick sensors irradiated to 1.…”