Design and Construction of a Modular NaI(Tl) array for Parity- and Time Reversal-Odd Measurements.*

One of the motivations to search for new physics Beyond the Standard Model (BSM) is to understand the baryon asymmetry present in the Universe, namely the discrepancy between the theoretical prediction of the baryon asymmetry based on the SM and the value obtained through observations of the cosmic microwave background. The Neutron Optics Parity and Time-Reversal EXperiment (NOPTREX) Collaboration seeks to measure signatures of parity-odd (P-odd) and time-reversal-symmetry-odd (T-odd) interactions in polarized neutron interactions with p-wave resonances in heavy nuclei in the eV energy range, which are well known to greatly amplify parity-odd asymmetries above the size expected for NN interactions by factors as large as 10^{6}. We will discuss our successful development of a modular NaI(Tl) current mode gamma detector array and data acquisition system which was designed and constructed at Eastern Kentucky University (EKU) and installed at the Los Alamos Neutron Science Center (LANSCE). We will discuss the process of developing the modular array, as well as the polarized n-γ resonance data collected with it in the recent 2024 LANSCE run cycle.