Cosmogenic background simulations for the DARWIN observatory at different underground locations

TL;DR

This paper uses Monte Carlo simulations to compare cosmogenic backgrounds at four underground sites for the DARWIN xenon detector, aiding site selection for low-background physics experiments.

Contribution

It provides detailed modeling of cosmogenic backgrounds at multiple underground locations specifically for the DARWIN observatory, highlighting the dominant sources of background relevant for site choice.

Findings

Production rates of unstable xenon isotopes and tritium vary by site.

Muon-induced neutron fluxes significantly contribute to backgrounds.

Site differences impact the expected cosmogenic background levels.

Abstract

Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay ($0\nu\beta\beta$), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We determine the production rates of unstable xenon isotopes and tritium due to muon-included neutron fluxes and muon-induced spallation. These are expected to represent the dominant contributions to cosmogenic backgrounds and thus the most relevant for site selection.