Speaker
Description
The DUNE Near Detector Liquid Argon Detector (ND-LAr) is a modular, pixelated liquid argon time projection chamber designed to faithfully reconstruct neutrino interactions in a very intense beam environment. One of its prototypes, the 2×2 Demonstrator, collected 4.5 days of data in the NuMI antineutrino beam at Fermilab in 2024. We study the pixel-level detector response using the charge collected per unit length, dQ/dx, of minimum-ionizing particles (MIPs). In addition to a primary peak, the MIP dQ/dx distribution exhibits a low-charge peak associated with long-range induced signals crossing the self-triggering threshold. We use a modern, GPU-accelerated simulation framework called TRED to model this effect and study the interplay between induction and threshold. We further develop two data-driven approaches to constrain the effective readout threshold: an L1-regularized method to sharpen the threshold turn-on, and a complementary method based on charge-blob boundaries identified with a convex-hull construction.