A linear optimal filtering approach for pileup noise removal in high-rate liquid ionization calorimeters

This paper extends the linear optimal filtering (LOF) technique to the treatment of pileup noise in high-rate liquid ionization calorimeters. A two-tuple pileup case is formulated by evaluating the χ² function defined over a set of signal samples. A first-order (linear) approximation applied to the result readily leads to the discovery of four linear FIR filters that are capable of continuous operation and amenable to hardware realization. Monte Carlo simulation is performed to validate the proposed approach using parameters extracted from the ATLAS liquid argon calorimeter readout system. The LOF yields accurate estimation of the pulse amplitude and arrival time in presence of signal pileup. A parallel as well as an iterative configuration of the LOF are discussed and contrasted in terms of hardware efficiency and execution speed.