Timing performance of radiation hard MALTA monolithic Pixel sensors

TL;DR

This paper reports on the timing performance of radiation-hard MALTA monolithic pixel sensors, demonstrating sub-2 ns resolution and high radiation tolerance suitable for high-energy physics experiments like the HL-LHC.

Contribution

It introduces the MALTA2 sensor with improved front-end design, achieving better timing resolution and radiation hardness compared to previous versions.

Findings

Timing resolution below 2 ns achieved

Radiation hardness up to 2 x 10^15 n_eq/cm^2 demonstrated

Uniform charge collection across pixel area

Abstract

The MALTA family of Depleted Monolithic Active Pixel Sensor (DMAPS) produced in Tower 180 nm CMOS technology targets radiation hard applications for the HL-LHC and beyond. Several process modifications and front-end improvements have resulted in radiation hardness up to $2 \times 10^{15}~1~\text{MeV}~\text{n}_{eq}/\text{cm}^2$ and time resolution below 2 ns, with uniform charge collection efficiency across the Pixel of size $36.4 \times 36.4~\mu\text{m}^2$ with a $3~\mu\text{m}^2$ electrode size. The MALTA2 demonstrator produced in 2021 on high-resistivity epitaxial silicon and on Czochralski substrates implements a new cascoded front-end that reduces the RTS noise and has a higher gain. This contribution shows results from MALTA2 on timing resolution at the nanosecond level from the CERN SPS test-beam campaign of 2021.