Investigation of proton spallation effect on Electron Emission Coefficient electrodes coated with metamaterial

The Electron Emission Coefficient (EEC) is a critical parameter in atomic and nuclear detectors. This study investigates the impact of the spallation process and metamaterial coatings (Graphene/hBN and Graphene/WC) on EEC under 30, 500, and 1000 MeV proton irradiation using the MCNPX code. Results indicate that both the spallation process, which produces a discrete particle spectrum, and the application of metamaterial layers significantly enhance EEC. When considering spallation with a 0.1 mm Graphene/WC coating, EEC increased by 122.36%, 49.15%, and 593.5% for silver, copper, and aluminum, respectively. Without the spallation process, these increases were 30.97%, 33.17%, and 196.61%. Specifically, incorporating the spallation phenomenon alongside Graphene/WC led to net EEC gains of 76.36% for silver, 27.84% for copper, and 22.86% for aluminum compared to baseline scenarios. Furthermore, Graphene/WC outperformed Graphene/hBN in increasing EEC across all electrodes by a factor ranging from 2.15 to 12.76. These findings demonstrate that combining Graphene/WC metamaterials with spallation effects offers a superior method for optimizing electron emission in electrode design.