Simulation and Evaluation of Surface Alpha Effects on LEGEND-200 Detectors

The LEGEND experiment seeks to measure neutrinoless double beta decay in Ge-76 using a source=detector experimental setup at LNGS. Using a phased deployment approach, the currently deployed LEGEND-200 has a discovery potential up over 10²⁷ years approaching the inverted hierarchy with the future LEGEND-1000 experiment seeking to increase this sensitivity by an order of magnitude. The sensitivity reach of all these experiments is based on an accurate understanding of the expected backgrounds and the expected detector response to a wide variety of event topologies, in particular alpha and beta events impacting the corresponding passivated/n+ sensitive surfaces of the various LEGEND-200 detectors. To this end, we have developed a combined electromagnetic and Geant4 simulation framework which can model the full detector response based on known detector efforts such as surface charge. In this talk, we will present the setup of these simulations and their results as well as an estimate for the potential effect of the detector response to the overall LEGEND-200 background budget.