Investigation of Chlorine Isotope Production in L200

LEGEND aims to be the most successful germanium-based, underground neutrinoless double-beta decay (0νββ) search. By maintaining an ultra-low background environment and building on the success of prior experiments, LEGEND aims to advance the field's sensitivity limits. The second phase, LEGEND-1000 (L1000), will deploy 1000 kg of enriched germanium detectors. The first phase, LEGEND-200 (L200), plays a crucial role in identifying and addressing unforeseen backgrounds to optimize future operations. This presentation focuses on investigating the production of chlorine isotopes in the liquid argon surrounding the detectors. These isotopes can form via cosmogenic muon interactions, where muons are captured by argon to create muonic atoms, or through muon-induced neutron interactions, particularly (n,p) reactions. The chlorine isotopes undergo beta decay into excited states, emitting beta particles and gamma rays which can produce background events with energies close to the anticipated 0νββ signal. Using L200 data, we assess the impact of these processes to evaluate their potential effect on the experiment’s sensitivity.