Performance Enhancement of Gas Electron Multipliers Using an Optimized Single-Conical Hole Geometry for Different Charged Particles

Abstract

Gas Electron Multipliers (GEMs) are essential detector components in modern high-energy physics experiments, where precise and stable detection of charged particles over a broad energy range is required. We present a comprehensive Garfield$^{++}$ and ANSYS-based study of conventional bi-conical and optimized single-conical GEM detectors to investigate the performance of the GEM detector for muons ($μ$), pions ($π$), kaons ($K$), and protons ($P$), which constitute the dominant charged particles measured directly in collider-based experiments. The aim is to examine the impact of particle-dependent ionization characteristics on charge amplification and ion backflow, and to evaluate the potential of an optimized GEM configuration for different leptons and hadrons. The conventional bi-conical GEM design does not always operate at optimal efficiency, as ion backflow can lead to space-charge accumulation and electric field distortions, ultimately limiting performance in high-rate environments. Thus, geometrical optimization is essential to address these limitations and enhance detector performance. A single-conical hole geometry is introduced and systematically compared with the conventional bi-conical design. For both of these configurations, the results exhibit clear and systematic variations in the detector performance with the particle type and the incident energy. The optimized geometry improves the balance between effective gain and ion backflow, demonstrating its potential for future high-rate MPGD applications.