Speaker
Description
Gas Electron Multipliers (GEMs) are a class of Micro-Pattern Gaseous Detectors (MPGDs) widely used in high-energy physics experiments for their excellent spatial resolution, high-rate capability, and operational robustness. However, their long-term performance can be affected by cumulative degradation effects. One such issue is the formation of insulating layers on the metallic surfaces of GEM foils, resulting from chemical interactions with the gas mixture or residual contaminants. These layers can lead to local charge buildup and induce undesired electron emission, a phenomenon known as the Malter effect. The emitted electrons may drift into GEM holes, generating spurious currents, premature gain saturation, and, in severe cases, electrical discharges. In this study, we use a simulation framework combining GMSH (for geometry modeling), Elmer (for electric field calculations), and Garfield++ (for electron transport and avalanche modeling) to explore how insulating surface layers influence GEM behavior. Electron emission is modeled using a tunneling-based description of the Malter effect. Preliminary results emphasize the role of spatial non-uniformity in the formation of insulating deposits and identify critical sites of charge accumulation. These insights contribute to a deeper understanding of charging-up phenomena and support the development of mitigation strategies for GEM detectors operating in high-rate conditions.
| Name of the speaker | Bruna Beatriz Tizoni Francisco |
|---|---|
| Eligible for the Georges Charpak Young Scientist Award. | yes |