Proposal of the Fuzzy Trigger for the Surface Detector of the Pierre Auger Observatory

• Published in: IEEE transactions on nuclear science Vol. 71; no. 6; pp. 1281 - 1291
• Main Authors: Szadkowski, Zbigniew, Pytel, Krzysztof
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Analog to digital converters; Artificial neural networks; Atmospheric modeling; Auger engineering radio array (AERA); Augers; Cerenkov counters; Cosmic rays; Detectors; Digital signal processing; Digitization; Discrete cosine transform; Field programmable gate arrays; field-programmable gate array (FPGA); finite impulse response (FIR); Fuzzy logic; infinity impulse response (IIR); Least mean squares methods; least means squares (LMS); Multipliers; Neural networks; Neutrino sources; Neutrinos; Observatories; Protons; radio-frequency interference (RFI); Radiofrequency interference; Sensors; Showers; Signal processing; Surface detectors; Terrestrial atmosphere; ultrahigh-energy cosmic ray (UHECR)
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2024.3386217

The standard first level triggers in the surface detectors [analyzing data in the field-programmable gate array (FPGA) just after the digitization in analog to digital converters (ADCs)] of the Pierre Auger Observatory were developed when FPGA was relatively simple and additionally expensive. A huge progress in electronics allows an implementation of very sophisticated mathematical algorithms in very powerful (a lot of FPGA fabric, embedded memories, and digital signal processing (DSP) blocks with very fast embedded multipliers) and relatively inexpensive FPGAs. A fuzzy logic (FL) is an alternative approach for a trigger based on a discrete cosine transform or artificial neural networks developed for the surface detector of the Pierre Auger Observatory. The aim of this article is to report on the trigger design that would allow one to distinguish the signal profiles from the Auger photo-multipliers (PMTs) of the water Cherenkov detectors originating from the neutrino-induced atmospheric showers with a high background of the proton showers. The algorithm has been successfully implemented in CycloneV and Arria10 FPGAs with reasonable resource occupancy and sufficient margin of a registered performance by 120 MHz sampling frequency. The FL trigger may support existing triggers in the Auger surface detector being optimized to identify neutrino-generated showers.