Simulation and Validation of the ICARUS PMT Adder-Board Response

The ICARUS liquid argon time projection chamber (LArTPC), operating as the Far Detector for the Fermilab Short-Baseline Neutrino (SBN) program, detects neutrinos by capturing ionization electrons and scintillation photons produced in neutrino–argon interactions. The scintillation photons are collected by the photomultiplier tubes (PMTs) that convert light into electrical signals for event reconstruction and triggering. In 2023, a new hardware component known as the adder board was introduced to improve the light-trigger efficiency for low-energy neutrino events (<300 MeV). This board sums, reshapes, and outputs the analog signals from 15 neighboring PMT channels. This work presents the first simulation of the adder-board response and its validation against ICARUS data. The simulated waveforms reproduce detector data with 93.2 % agreement in amplitude. The validated model will be integrated into the ICARUS trigger-simulation framework, enabling more accurate modeling and improved detection of low-energy neutrino events.