Gain stabilization in Micro Pattern Gaseous Detectors: methodology and results

TL;DR

This paper introduces a comprehensive methodology for characterizing and understanding gain stabilization in Micro Pattern Gaseous Detectors, focusing on charging-up effects and their impact on detector performance over time.

Contribution

The paper presents a new, robust methodology for gain transient characterization in MPGDs, validated with THWELL and RPWELL detectors, offering insights into charging-up processes.

Findings

Validated charging-up/charging-down model for gain stabilization

Identified transient behaviors upon abrupt changes in detector conditions

Enhanced understanding of insulator effects on gain stability

Abstract

The phenomenon of avalanche-gain variations over time, particularly in Micro Pattern Gaseous Detectors (MPGD) incorporating insulator materials, have been generally attributed to electric-field modifications resulting from "charging-up" effects of the insulator. A robust methodology for characterization of gain-transients in such detectors is presented. It comprises three guidelines: detector initialization, long-gain stabilization monitoring and imposing transients by applying abrupt changes in operation conditions. Using THWELL and RPWELL detectors, we validated the proposed methodology by assessing a charging-up/charging-down model describing the governing processes of gain stabilization. The results provide a deeper insight into these processes, reflected by different transients upon abrupt variations of detector gain or the irradiation rate. This methodology provides a handle for future investigations of the involved physics phenomena in MPGD detectors comprising insulating components.