Estimação de energia para calorímetros finamente segmentados operando em condições severas de empilhamento de sinais

Abstract

Signal estimation problems are common in several areas of engineering. In such problems, usually, one works with equations or models from which specific parameters need to be calculated so that properties and characteristics of signals can be studied. In high energy calorimetry, for example, the energy of the particle is absorbed and sampled by the reading electronics that provides a characteristic pulse, where its amplitude is proportional to the deposited energy. However, in conditions of high event rate and high luminosity, such as those observed in the LHC particle accelerator, operated at CERN, the sampled signal may contain information about adjacent collisions, resulting in the effect of pile-up and making it difficult to estimate the amplitude of the signal of interest. In this context, a deterministic model for the signal, typically adopted for amplitude estimation, becomes unfeasible for severe levels of pile-up. Thus, this work proposes a method for amplitude (energy) estimation based on the Wiener-Hopf filter theory, in which a model for the representation of the signals is not necessary. To evaluate the efficiency of the

proposed approach, a signal simulation tool was developed and data sets were genera- ted considering the ATLAS tile calorimeter at the LHC operating under different signal

pile-up conditions. In addition, data acquired during nominal operation of the LHC was used. The results show that the efficiency of the proposed approach surpasses those of methods currently used for severe signal pile-up conditions, providing gains in terms of dispersion of the estimation error around 30% for real data and simulated data. It was also observed that for low and medium occupation ranges, the efficiency of the proposed method is surpassed by alternative methods.