Simulation of gain stability of THGEM gas-avalanche particle detectors

TL;DR

This paper presents a simulation toolkit integrated with Garfield++ to study charging-up effects on gain stability in THGEM detectors, revealing how electrode properties influence stabilization time and matching experimental data.

Contribution

It introduces a dedicated simulation tool for charging-up processes in THGEM detectors, enabling systematic analysis of gain stability influenced by physical parameters.

Findings

Gain stabilization occurs after tens to hundreds of pC charge accumulation.

Electrode thickness and voltage significantly affect gain evolution.

Simulation results align with previous experimental observations.

Abstract

Charging-up processes affecting gain stability in Thick Gas Electron Multipliers (THGEM) were studied with a dedicated simulation toolkit. Integrated with Garfield++, it provides an effective platform for systematic phenomenological studies of charging-up processes in MPGD detectors. We describe the simulation tool and the fine-tuning of the step-size required for the algorithm convergence, in relation to physical parameters. Simulation results of gain stability over time in THGEM detectors are presented, exploring the role of electrode-thickness and applied voltage on its evolution. The results show that the total amount of irradiated charge through electrode's hole needed for reaching gain stabilization is in the range of tens to hundreds of pC, depending on the detector geometry and operational voltage. These results are in agreement with experimental observations presented previously.