Study of MALTA2, a Depleted Monolithic Active Pixel Sensor, with grazing angles at CERN SPS 180 GeV/c hadron beam

TL;DR

This paper evaluates MALTA2, a radiation-hard monolithic pixel sensor, under grazing angles at CERN SPS, demonstrating its high detection efficiency and active depth after irradiation, suitable for future collider experiments.

Contribution

It presents the first comprehensive testing of MALTA2 sensors at grazing angles post-irradiation, highlighting their robustness and performance in extreme conditions.

Findings

High detection efficiency maintained after irradiation

Active depth estimation aligns with design expectations

Sensor performance varies with grazing angle

Abstract

MALTA2 is a Depleted Monolithic Active Pixel Sensor designed to meet the challenging requirements of future collider experiments, in particularly extreme radiation tolerance and high hit rate. The sensor is fabricated in a modified Tower 180 nm CMOS imaging technology to mitigate performance degradation caused by 100 MRad of Total Ionising Dose and greater than 10^{15} 1 MeV n_{eq}/cm^2 of Non-Ionising Energy Loss. MALTA2 samples have been tested during the CERN SPS test beam campaign in 2023-2024, before and after irradiation at a fluence of 1 $\times$ 10^{15} 1 MeV n_{eq}/cm^2. The sensors were positioned at various inclinations relative to the beam, covering grazing angles from 0 to 60 degrees. This contribution presents measurements of detection efficiency and cluster size as functions of these angles, along with an estimation of the active depth of the depleted region based on the test beam results.