Radiation hardness of small-pitch 3D pixel sensors up to HL-LHC fluences

TL;DR

This paper reports on the development and testing of small-pitch 3D silicon pixel sensors for HL-LHC, demonstrating high radiation tolerance and low operational voltage at extreme fluences.

Contribution

It introduces a new generation of small-pitch 3D pixel sensors with improved radiation hardness suitable for HL-LHC upgrades.

Findings

Achieved 97% hit efficiency at 1.4×10^{16} n_{eq}/cm^{2} fluence with only 100 V.

Power dissipation remains low at 13 mW/cm^{2} at -25°C.

Operational voltage is significantly lower than previous sensor generations.

Abstract

A new generation of 3D silicon pixel detectors with a small pixel size of 50$\times$50 and 25$\times$100 $\mu$m$^{2}$ is being developed for the HL-LHC tracker upgrades. The radiation hardness of such detectors was studied in beam tests after irradiation to HL-LHC fluences up to $1.4\times10^{16}$ n$_{\mathrm{eq}}$/cm$^2$. At this fluence, an operation voltage of only 100 V is needed to achieve 97% hit efficiency, with a power dissipation of 13 mW/cm$^2$ at -25$^{\circ}$C, considerably lower than for previous 3D sensor generations and planar sensors.