Geant4 based library SCoRe4 for Surface Contamination and Roughness Effects simulations in rare event search experiments

Abstract

Surface simulations are important for accurately modeling particle interactions in experiments where background contributions from surface contaminants can significantly affect detector performance. In rare event searches, such as dark matter or neutrinoless double beta decay experiments, standard Geant4 simulations typically assume perfectly smooth surfaces, neglecting the microscopic roughness that exists in real materials. This simplification can lead to inaccurate predictions of energy deposition. To address this limitation, I developed SCoRe4, a Geant4-based library designed to simulate more realistic surface roughness based on experimentally measurable parameters. The code allows users to generate patches of simplified rough surface geometries across a wide range of scales - from square millimeters to square meters - while maintaining computational efficiency. SCoRe4 is open source and can be easily integrated into existing Geant4 setups. This work presents the structure, implementation, and example application of SCoRe4,as well as its potential use in improving the accuracy of background modeling in rare event physics.