An ageing study of resistive micromegas for the HL-LHC environment

TL;DR

This study evaluates the long-term durability of resistive micromegas detectors under HL-LHC conditions, showing they maintain performance after extensive irradiation, supporting their use in high-radiation environments.

Contribution

It provides the first comprehensive ageing assessment of resistive micromegas detectors for HL-LHC, confirming their stability and performance after prolonged irradiation.

Findings

Detectors showed no degradation after irradiation simulating five years of HL-LHC operation.

Performance metrics like gain and energy resolution remained stable post-irradiation.

Tracking efficiency and spatial resolution were maintained in irradiated detectors.

Abstract

Resistive-anode micromegas detectors are in development since several years, in an effort to solve the problem of sparks when working at high flux and high ionizing radiation like in the HL-LHC (up to ten times the luminosity of the LHC). They have been chosen as one of the technologies that will be part of the ATLAS New Small Wheel project (forward muon system). An ageing study is mandatory to assess their capabilities to handle the HL-LHC environment on a long-term period. A prototype has been exposed to several types of irradiation (X-rays, cold neutrons, $^{60}$Co gammas and alphas) above the equivalent charge produced at the detector in five HL-LHC running years without showing any degradation of the performances in terms of gain and energy resolution. This study has been completed with the characterization of the tracking performances in terms of efficiency and spatial resolution, verifying the compatibility of results obtained with both resistive micromegas detectors, irradiated and non-irradiated one.