Performance of Thin Planar \textit{n-on-p} silicon pixels after HL-LHC radiation fluences

TL;DR

This study evaluates the performance of 130 μm thick n-on-p silicon pixel sensors for the ATLAS detector upgrade at HL-LHC, demonstrating high efficiency and durability after irradiation at high fluences.

Contribution

The paper presents new radiation-hard n-on-p silicon pixel sensors tested before and after irradiation, suitable for high-fluence environments like HL-LHC upgrades.

Findings

Hit-efficiency exceeds 97% at fluences up to 7×10^15 n_eq/cm^2

Sensors maintain 88% efficiency at 1.3×10^16 n_eq/cm^2

Power consumption remains within acceptable limits after irradiation

Abstract

The tracking detector of ATLAS, one of the experiments at the Large Hadron Collider (LHC), will be upgraded in 2024-2026 to cope with the challenging environment conditions of the High Luminosity LHC (HL-LHC). The LPNHE, in collaboration with FBK and INFN, has produced 130~$\mu$m thick $n-on-p$ silicon pixel sensors which can withstand the expected large particle fluences at HL- LHC, while delivering data at high rate with excellent hit efficiency. Such sensors were tested on beam before and after irradiation both at CERN-SPS and at DESY, and their performances are presented in this paper. Beam test data indicate that these detectors are suited for all the layers where planar sensors are foreseen in the future ATLAS tracker: hit-efficiency is greater than 97\% for fluences $\Phi \lesssim 7\times10^{15}\rm{n_{eq}/cm^2}$ and module power consumption is within the specified limits. Moreover, at a fluence $\Phi = 1.3\times10^{16}\rm{n_{eq}/cm^2}$, hit-efficiency is still as high as 88\% and charge collection efficiency is about 30\%.