Toward a Quasi-Background-Free Measurement in LEGEND-1000 with Custom Synthesized PEN*

Identification and mitigation of background radiation is of utmost importance for enabling discovery potential for rare event experiments. The neutrinoless double beta decay experiment LEGEND, utilizes background suppression to reach discovery of T_1/2>10²⁸yrs with the isotope ⁷⁶Ge. Poly(ethylene-2,6-naphthalate) (PEN) has emerged as a highly promising material for LEGEND due to its intrinsic scintillating properties and its structural behavior at both room and cryogenic temperatures. PEN has been successfully implemented in the LEGEND-200 experiment as both an active material and a structural component within the detector assembly. Looking towards the next-generation experiment, LEGEND-1000 will further reduce background radiation to <10^-5 cts/(keV kg yr). To achieve this goal, we are looking to produce custom PEN-G and expand applications to further improve background radiation identification. We will present the radiopurity and scintillator properties of custom synthesized PEN and current applications in LEGEND-200 and future applications in LEGEND-1000.