Preliminary Background Modeling of the MAJORANA DEMONSTRATOR Hardware Upgrade

The MAJORANA DEMONSTRATOR is a neutrinoless double-beta decay experiment located at the Sanford Underground Research Facility in Lead, South Dakota. The DEMONSTRATOR contains an array of 44kg of Ge detectors, of which 30 kg are enriched in the neutrinoless double-beta decay candidate isotope ⁷⁶Ge. During 2020, a module of the DEMONSTRATOR was upgraded to replace its cables and connectors, to add more shielding, and to swap in 4 inverted-coaxial point contact detectors that will also be used in LEGEND-200. The Monte Carlo simulation geometry of the MAJORANA DEMONSTRATOR was updated to the reflect the changes made during the upgrade, and new simulations were run to calculate the effect of these upgrades on the expected background contribution of the DEMONSTRATOR. The changes to the MAJORANA DEMONSTRATOR simulation geometry and expected background rate of the DEMONSTRATOR will be discussed.