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Estimated Pulse Height Spectrum with Pulse Pile-Up Correction for Neutron Monitor of Mexico City

R. García Gínez, J.F. Valdés-Galicia, M.A. Anzorena Méndez, O. Musalem, A. Hurtado, E. Ortiz, L.X. Gónzalez

in 35th International Cosmic Ray Conference

Contribution: pdf


The operating principles of Neutron Monitors are nuclear reactions within the proportional counters. The output signal of these is an electric pulse for every secondary cosmic ray particle that interacts with the detector gas. The amplitude of the pulse signal reflects the amount of charge generated on each individual interaction. The estimated pulse height distribution provides an estimate of the energy deposited. The random nature of the cosmic radiation, in addition to the operating characteristics of both the detector and the associated electronic system, lead to a phenomenon called pulse pile-up. The effect of the pulse pile-up on the recorded pulse height distribution, may be seen in the added wings in the energy peaks of the distribution. This reduces the energy resolution of the instrument.

In this work, we describe an algorithm that takes advantage of digital signal processing techniques with the purpose of calculating the pulse amplitude distribution reducing the distortion caused by pulse pileup. The algorithm was written in python, using numpy and scipy libraries. The results of applying the algorithm to the neutron monitor operating in Mexico City are presented.