Studies to improve the liquid argon veto in LEGEND

Neutrinoless double beta decay is a hypothesized lepton-number-violating process in which two protons decay to two neutrons, producing two electrons but no electron neutrinos. The LEGEND collaboration will search for this decay using high purity germanium detectors enriched in ⁷⁶Ge with the sensitivity goal of half-lifes in excess of 10²⁸ yr. A staged approach is being proposed in which a phase-1 200 kg (L-200) 76Ge detector array will be instrumented, followed by a phase-2 at a ton scale (L-1000). To increase the light collection efficiency of the L-200 liquid argon veto, several possible germanium detector array geometries are being explored using simulated optical probability maps. These maps, created with Geant4, are used to calculate photon detection probability as a function of position. This talk will demonstrate the power of this tool. For L-1000, an even lower background index is desired. To reach this goal, xenon doped argon is being investigated at the University of New Mexico. By adding 10 ppm of xenon to argon, the scintillation light of argon is shifted from 128 nm to 175 nm. Argon is more transparent and most materials are more reflective at 175 nm. Thus xenon doped argon should yield more light than pure argon. The results of this xenon doping will be presented.