Design, upgrade and characterization of the silicon photomultiplier front-end for the AMIGA detector at the Pierre Auger Observatory

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to complement the study of ultra-high-energy cosmic rays (UHECR) by measuring the muon content of extensive air showers (EAS). It consists of an array of 61 water Cherenkov detectors on a denser spacing in combination with underground scintillation detectors used for muon density measurement. Each detector is composed of three scintillation modules, with 10 m2 detection area per module, buried at 2.3 m depth, resulting in a total detection area of 30 m2 . Silicon photomultiplier sensors (SiPM) measure the amount of scintillation light generated by charged particles traversing the modules. In this paper, the design of the front-end electronics to process the signals of those SiPMs and test results from the laboratory and from the Pierre Auger Observatory are described. Compared to our previous prototype, the new electronics shows a higher performance, higher efficiency and lower power consumption, and it has a new acquisition system with increased dynamic range that allows measurements closer to the shower core. The new acquisition system is based on the measurement of the total charge signal that the muonic component of the cosmic ray shower generates in the detector.Fil: Aab, A.. Radboud Universiteit Nijmegen; Países BajosFil: Abreu, P.. Instituto Superior Tecnico; PortugalFil: Aglietta, M.. Istituto Nazionale di Astrofisica; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Albury, J. M.. University of Adelaide; AustraliaFil: Allekotte, Ingomar. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Almela, A.. Universidad Nacional de San Martín; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Alvarez Muñiz, J.. Universidad de Santiago de Compostela; EspañaFil: Alves Batista, R.. Radboud Universiteit Nijmegen; Países BajosFil: Anastasi, G. A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Anchordoqui, Luis A.. City University of New York; Estados UnidosFil: Andrada, Betiana Eugenia. Universidad Nacional de San Martín; ArgentinaFil: Andringa, S.. Instituto Superior Tecnico; PortugalFil: Aramo, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Araújo Ferreira, P. R.. Rwth Aachen University; AlemaniaFil: Asorey, H.. Universidad Nacional de San Martín; ArgentinaFil: Assis, P.. Instituto Superior Tecnico; PortugalFil: Avila, G.. Observatorio Pierre Auger; ArgentinaFil: Badescu, A. M.. University Politehnica Of Bucharest; RumaniaFil: Bakalova, A.. The Czech Academy Of Sciences; República ChecaFil: Balaceanu, A.. “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Bucharest-Magurele; RumaniaFil: Barbato, F.. Università degli Studi di Napoli Federico II; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Barreira Luz, R. J.. Instituto Superior Tecnico; PortugalFil: Becker, K. H.. Bergische Universität Wuppertal; AlemaniaFil: Bellido, J. A.. University of Adelaide; AustraliaFil: Berat, C.. Universite Grenoble Alpes; FranciaFil: Bertaina, M. E.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Biermann, P. L.. Max Planck Institute For Radio Astronomy; AlemaniaFil: Bister, T.. Rwth Aachen University; AlemaniaFil: Gollan Scilipotti, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; Argentin

Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with the Pierre Auger Observatory

We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop.Fil: Aab, A.. Radboud Universiteit Nijmegen; Países BajosFil: Abreu, P.. Instituto Superior Tecnico; PortugalFil: Aglietta, M.. Osservatorio Astrofisico di Torino; Italia. Istituto Nazionale di Astrofisica; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Albury, J. M.. University of Adelaide; AustraliaFil: Allekotte, Ingomar. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Almela, Daniel Alejandro. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Alvarez Muñiz, J.. Universidad de Santiago de Compostela; EspañaFil: Alves Batista, R.. Radboud Universiteit Nijmegen; Países BajosFil: Anastasi, G. A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Anchordoqui, L.. University of New York; Estados UnidosFil: Andrada, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Andringa, S.. Instituto Superior Tecnico; PortugalFil: Aramo, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Araújo Ferreira, P. R.. Rwth Aachen University; AlemaniaFil: Asorey, Hernán Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Assis, P.. Instituto Superior Tecnico; PortugalFil: Avila, Gualberto. Observatorio Pierre Auger. Observatorio Sur - Malargue; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Badescu, A. M.. University Politehnica of Bucharest; RumaniaFil: Bakalova, A.. Czech Academy of Sciences; República ChecaFil: Balaceanu, A.. “Horia Hulubei” National Institute for Physics and Nuclear Engineering; RumaniaFil: Barbato, F.. Università degli Studi di Napoli Federico II; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Barreira Luz, R. J.. Instituto Superior Técnico; PortugalFil: Becker, K. H.. Bergische Universität Wuppertal; AlemaniaFil: Bellido, J. A.. University of Adelaide; AustraliaFil: Berat, C.. Universite Grenoble Alpes; Francia. Centre National de la Recherche Scientifique; FranciaFil: Bertaina, M. E.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche). Grupo de Partículas y Campos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Biermann, P. L.. Max-Planck-Institut für Radioastronomie; AlemaniaFil: Bister, T.. Aachen University; AlemaniaFil: Mollerach, Maria Silvia. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Calibration of the underground muon detector of the Pierre Auger Observatory

To obtain direct measurements of the muon content of extensive air showers with energy above 101 eV, the Pierre Auger Observatory is currently being equipped with an underground muon detector (UMD), consisting of 219 10 m2-modules, each segmented into 64 scintillators coupled to silicon photomultipliers (SiPMs). Direct access to the shower muon content allows for the study of both of the composition of primary cosmic rays and of high-energy hadronic interactions in the forward direction. As the muon density can vary between tens of muons per m close to the intersection of the shower axis with the ground to much less than one per m when far away, the necessary broad dynamic range is achieved by the simultaneous implementation of two acquisition modes in the read-out electronics: the binary mode, tuned to count single muons, and the ADC mode, suited to measure a high number of them. In this work, we present the end-to-end calibration of the muon detector modules: first, the SiPMs are calibrated by means of the binary channel, and then, the ADC channel is calibrated using atmospheric muons, detected in parallel to the shower data acquisition. The laboratory and field measurements performed to develop the implementation of the full calibration chain of both binary and ADC channels are presented and discussed. The calibration procedure is reliable to work with the high amount of channels in the UMD, which will be operated continuously, in changing environmental conditions, for several years.Fil: Aab, A.. Radboud Universiteit Nijmegen; Países BajosFil: Abreu, P.. Instituto Superior Tecnico; PortugalFil: Aglietta, M.. Istituto Nazionale di Astrofisica; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Albury, J. M.. University of Adelaide; AustraliaFil: Allekotte, Ingomar. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Almela, A.. Universidad Tecnológica Nacional; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Alvarez Muñiz, J.. Universidad de Santiago de Compostela; EspañaFil: Alves Batista, R.. Radboud Universiteit Nijmegen; Países BajosFil: Anastasi, G. A.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Anchordoqui, Luis A.. City University of New York; Estados UnidosFil: Andrada, B.. Comisión Nacional de Energía Atómica; ArgentinaFil: Andringa, S.. Instituto Superior Tecnico; PortugalFil: Aramo, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Araújo Ferreira, P. R.. Rwth Aachen University; AlemaniaFil: Arteaga Velázquez, J. C.. Universidad Michoacana de San Nicolás de Hidalgo; MéxicoFil: Asorey, Hernán Gonzalo. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Assis, P.. Instituto Superior Tecnico; PortugalFil: Avila, G.. Comisión Nacional de Energía Atómica; ArgentinaFil: Badescu, A.M.. University Politehnica Of Bucharest; RumaniaFil: Bakalova, A.. Institute Of Physics Of The Czech Academy Of Sciences; República ChecaFil: Balaceanu, A.. “Horia Hulubei” National Institute for Physics and Nuclear Engineering; RumaniaFil: Barbato, F.. Laboratori Nazionali del Gran Sasso; Italia. Gran Sasso Science Institute; ItaliaFil: Barreira Luz, R. J.. Instituto Superior Tecnico; PortugalFil: Becker, K. H.. Bergische Universität Wuppertal; AlemaniaFil: Bellido, J. A.. Universidad Nacional de San Agustin de Arequipa; Perú. University of Adelaide; AustraliaFil: Berat, C.. Universite Grenoble Alpes; FranciaFil: Bertaina, M. E.. Università di Torino; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Biermann, P. L.. Max Planck Institute For Radio Astronomy; AlemaniaFil: Gollan Scilipotti, Fernando Daniel. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia Física (Centro Atómico Constituyentes). Proyecto Tandar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Deep sea tests of a prototype of the KM3NeT digital optical module

The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deepwaters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same (40)Kdecay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions

Detection potential of the KM3NeT detector for high-energy neutrinos from the Fermi bubbles

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E 2 spectrum from two large areas, spanning 50 above and below the Galactic centre (the ‘‘Fermi bubbles’’). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles with the future multi-km3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km3 of instrumented volume. The effect of a possible lower cutoff is also considered.Published7–141.8. Osservazioni di geofisica ambientaleJCR Journalrestricte

Expansion cone for the 3-inch PMTs of the KM3NeT optical modules

[EN] Detection of high-energy neutrinos from distant astrophysical sources will open a new window on the Universe. The detection principle exploits the measurement of Cherenkov light emitted by charged particles resulting from neutrino interactions in the matter containing the telescope. A novel multi-PMT digital optical module (DOM) was developed to contain 31 3-inch photomultiplier tubes (PMTs). In order to maximize the detector sensitivity, each PMT will be surrounded by an expansion cone which collects photons that would otherwise miss the photocathode. Results for various angles of incidence with respect to the PMT surface indicate an increase in collection efficiency by 30% on average for angles up to 45 degrees with respect to the perpendicular. Ray-tracing calculations could reproduce the measurements, allowing to estimate an increase in the overall photocathode sensitivity, integrated over all angles of incidence, by 27% (for a single PMT). Prototype DOMs, being built by the KM3NeT consortium, will be equipped with these expansion cones.This work is supported through the EU, FP6 Contract no. 011937, FP7 grant agreement no. 212252, and the Dutch Ministry of Education, Culture and Science.Adrián Martínez, S.; Ageron, M.; Aguilar, JA.; Aharonian, F.; Aiello, S.; Albert, A.; Alexandri, M.... (2013). Expansion cone for the 3-inch PMTs of the KM3NeT optical modules. Journal of Instrumentation. 8(3):1-19. https://doi.org/10.1088/1748-0221/8/03/T03006S1198