Mitigating Deadtime in Distributed Optical Arrays: A Liveness-Aware Trigger Approach for High-Energy Neutrino Detection

Abstract

Large-scale neutrino observatories operate under unavoidable detector deadtime arising from photomultiplier saturation, digitizer limits, and front-end readout constraints. Conventional coincidence-based trigger logic implicitly assumes continuous sensor availability and therefore suffers systematic efficiency loss when channels become temporarily non-live. This work presents the design of a liveness-aware trigger architecture targeting low-latency FPGA deployment in distributed optical arrays. We introduce a recursive Infinite Impulse Response (IIR) update law implemented as a fully synthesizable pipeline that constructs a continuity-preserving effective observable at each sensor node. Rather than collapsing during non-liveness intervals, the observable decays smoothly while retaining phase and amplitude information relevant for network-level coherence estimation. By explicitly separating continuous measurement construction from discrete trigger decision logic, the proposed architecture enables graceful degradation under partial channel non-liveness. Performance is evaluated using a hybrid validation framework that combines representative event topologies derived from IceCube Open Data with a hardware-accurate signal and noise model spanning a wide dynamic range. Simulation results demonstrate that the proposed trigger sustains high event recovery efficiency in regimes of elevated deadtime probability, where conventional coincidence logic degrades substantially. Furthermore, the continuity-preserving observable yields up to a two-order-of-magnitude improvement in effective signal-to-noise ratio, enabling robust detection under strong saturation and non-ideal operating conditions. This method provides a robust foundation for next-generation firmware-level trigger strategies in large-scale, noise-dominated detector systems.