Mitigation strategies for 42Ar/42K background reduction using encapsulation with ultra-pure plastic for the LEGEND experiment

Abstract

Neutrinoless double-beta (0$\nu\beta\beta$) decay is the most compelling approach to determine the Majorana nature of neutrino and measure effective Majorana neutrino mass. The LEGEND collaboration is aiming to look for 0$\nu\beta\beta$ decay of ${}^{76}$Ge with unprecedented sensitivity. If underground-sourced argon is not available, the cosmogenically-induced isotope ${}^{42}$Ar and its decay progeny ${}^{42}$K in the liquid argon active veto could create a challenging background for the 0$\nu\beta\beta$ signal. We are studying methodologies to mitigate the ${}^{42}$K background. In order to achieve this, encapsulation of germanium detectors with 3D-printed technologies using low background material are currently under investigation. Simulation results of Poly(ethylene 2,6- naphthalate) (PEN) encapsulation of germanium detectors and plans to study other potential materials are presented.