Diseño y desarrollo de la electrónica de los emisores acústicos para los sistemas de posicionamiento y calibración de telescopios submarinos de neutrinos

Tesis por compendioNeutrino telescopes are a new way of looking at the Universe. For more than a decade these structures are being designed to study the Universe from a new point of view, that is, from the particles generated in the cosmic accelerators of particles. These infrastructures are not only useful to study the Universe, but they can also be used in the field of Particle Physics and even in the study of underwater life. Most of these telescopes are based on the detection of the so-called Cherenkov light using photomultipliers, the difference between them lies in the medium in which they are located (ice or water) and in the infrastructure used. Specifically, European telescopes mount these photomultipliers in an underwater vertical structure anchored at great depth, which is under the influence of sea currents. For this reason they suffer displacements that affect the location of the photomultipliers and it becomes necessary to implement a positioning system for the telescope to be functional. For this, an acoustic system consisting of emitters anchored to the sea floor and receivers located at the different levels of the vertical structure is used. One of the objectives of the present thesis is the development of these acoustic emitters. For this purpose we have developed different laboratory prototypes with different features until obtaining an improved prototype that was installed and tested in ANTARES and NEMO telescopes. This showed that the prototype worked perfectly within the established requirements and then, we proceed to design a final version of the much more powerful and functional emitter, acoustic beacon, to be mounted inside aluminum vessels together with an omnidirectional acoustic transducer, which will be located in anchored positions of the new KM3NeT neutrino telescope. In collaboration with the MSM Company, 18 acoustic beacons were developed for KM3NeT-ARCA being two of them installed in the first marine campaign at the end of 2015, and being able then to verify their correct operation. On the other hand, interaction of ultraenergetic neutrinos with matter also produces a thermoacoustic pulse with bipolar form, axial symmetry and highly directive. The feasibility of the acoustic detection technique and the possibility of implementing it in these telescopes have been under study for years. In order to test and calibrate this technique, it is necessary to have an acoustic emitter system able of generating a signal similar to the neutrino signature. This has been the second objective developed in this thesis. To achieve this objective, a compact and versatile calibrator based on an array of acoustic transducers using parametric generation has been designed. Given the complexity of the pulse to emulate and the novelty of the technique to be used, it has been necessary to carry out different laboratory tests in order to obtain suitable transducers and electronics able of making them to work at the required power and efficiency. The positive results obtained in this line suggest that we will be able to obtain a full functional neutrino acoustic calibrator soon. Finally, I would like to mention that I have participated in the different research and activities described in the thesis, putting especial emphasis in the development of the electronics and the software/firmware of the developed acoustic emitters.Los telescopios de neutrinos son una nueva forma de observar el Universo. Desde hace más de una década se están diseñando este tipo de estructuras con el propósito de estudiar el Universo desde un nuevo punto de vista, el de las partículas que se generan en los aceleradores de partículas cósmicos. Estas infraestructuras no solo se limitan al estudio del Universo, sino que también pueden ser utilizadas en el campo de la Física de partículas e incluso en el estudio de la vida submarina. La mayoría de estos telescopios se basan en la detección de la llamada luz de Cherenkov mediante fotomultiplicadores, la diferencia entre ellos radica en el medio en que se ubican (hielo o agua) y en la infraestructura utilizada. Concretamente, los telescopios europeos montan dichos fotomultiplicadores en una estructura vertical submarina anclada a gran profundidad, la cual está sometida a la influencia de las corrientes marinas. Por este motivo sufren desplazamientos que afectan a la localización de los fotomultiplicadores y se hace necesaria la implementación de un sistema de posicionamiento para que el telescopio sea funcional. Para ello se utiliza un sistema acústico consistente en unos emisores anclados al suelo marino y unos receptores situados en los diferentes niveles de la estructura vertical. Uno de los objetivos de la presente tesis es el desarrollo de estos emisores acústicos. Con este fin se han desarrollado diferentes prototipos de laboratorio con los que se han ido escalando prestaciones hasta obtener un prototipo que ha sido instalado y testeado en los telescopios ANTARES y NEMO. Así se demostró que el prototipo funcionaba perfectamente dentro de los requisitos establecidos, pasándose a diseñar una versión final del emisor acústico mucho más potente y funcional para ser montada dentro de vasijas de aluminio junto con un traductor omnidireccional en las anclas del nuevo telescopio de neutrinos KM3NeT. Conjuntamente con la empresa MSM se elaboraron 18 equipos para KM3NeT-ARCA, dos de los cuales fueron instalados en la primera campaña marina a finales de 2015 comprobándose su correcto funcionamiento. Por otro lado, la interacción de los neutrinos ultraenergéticos con la materia también produce un pulso termoacústico con forma bipolar, simetría axial y altamente directivo. Desde hace años se está estudiando la viabilidad de la técnica de detección acústica y la posibilidad de implementarla en dichos telescopios. Para poder poner a prueba y calibrar dicha técnica es necesario disponer de un sistema emisor acústico que sea capaz de generar una señal similar a la descrita. Este ha sido el segundo objetivo desarrollado en esta tesis. Para ello se ha diseñado un calibrador compacto y versátil basado en un array de transductores acústicos usando generación paramétrica. Dada la complejidad del pulso a emular y lo novedoso de la técnica a utilizar, se ha requerido la realización de numerosas pruebas de laboratorio con el fin de conseguir unos transductores adecuados y la electrónica capaz de hacerlos funcionar a la potencia y eficiencia requerida. Los positivos resultados obtenidos en esta línea hacen prever que, en breve, podremos obtener un calibrador acústico de neutrinos funcional. Finalmente, cabe reseñar que he participado en las diferentes investigaciones y actividades que se describen en la tesis, siendo mi cometido principal el desarrollo tanto de la electrónica como de los diferentes softwares/firmwares implicados en los emisores acústicos desarrollados.Els telescopis de neutrins són una nova forma d'observar l'Univers. Des de fa més d'una dècada s'estan dissenyant aquest tipus d'estructures amb el propòsit d'estudiar l'Univers des d'un nou punt de vista, el de les partícules que es generen en els acceleradors de partícules còsmics. Estes infraestructures no sols es limiten a l'estudi de l'Univers, sinó que també poden ser utilitzades en el camp de la Física de partícules i fins i tot en l'estudi de la vida submarina. La majoria d'aquests telescopis es basen en la detecció de l'anomenada llum de Cherenkov per mitjà de fotomultiplicadors, la diferència entre ells radica en el mig en què s'ubiquen (gel o aigua) i en la infraestructura utilitzada. Concretament, els telescopis europeus munten dits fotomultiplicadors en una estructura vertical submarina ancorada a gran profunditat, la qual està sotmesa a la influència dels corrents marins. Per este motiu pateixen desplaçaments que afecten a la localització dels fotomultiplicadors i es fa necessària la implementació d'un sistema de posicionament per a què el telescopi siga funcional. Per a això s'utilitza un sistema acústic consistent en uns emissors ancorats al sòl marí i uns receptors situats en els diferents nivells de l'estructura vertical. Un dels objectius de la present tesi és el desenvolupament d'aquests emissors acústics. Amb este fi s'han desenvolupat diferents prototips de laboratori amb els quals s'han anat escalant prestacions fins a obtindre un prototip que ha sigut instal·lat i testeat en els telescopis ANTARES i NEMO. Així es va demostrar que el prototip funcionava perfectament dins dels requisits establerts, passant-se a dissenyar una versió final de l'emissor acústic molt més potent i funcional per a ser muntada dins d'atuells d'alumini junt amb un traductor omnidireccional en les àncores del nou telescopi de neutrins KM3NeT. Conjuntament amb l'empresa MSM es van elaborar 18 equips per a KM3NeT-ARCA, dos dels quals van ser instal·lats en la primera campanya marina a finals de 2015 comprovant-se el seu correcte funcionament. D'altra banda, la interacció dels neutrins ultraenergètics amb la matèria també produeix un pols termoacústic amb forma bipolar, simetria axial i altament directiu. Des de fa anys s'està estudiant la viabilitat de la tècnica de detecció acústica i la possibilitat d'implementar-la en els esmentats telescopis. Per a poder posar a prova i calibrar esta tècnica és necessari disposar d'un sistema emissor acústic que siga capaç de generar un senyal semblant al descrit. Aquest ha sigut el segon objectiu desenvolupat en aquesta tesi. Per a això s'ha dissenyat un calibrador compacte i versàtil basat en un array de transductores acústics utilitzant generació paramètrica. Donada la complexitat del pols a emular i la novetat de la tècnica a utilitzar, s'ha requerit la realització de nombroses proves de laboratori a fi d'aconseguir uns transductors adequats i l'electrònica capaç de fer-los funcionar a la potència i eficiència requerida. Els positius resultats obtinguts en esta línia fan preveure que, en breu, podrem obtindre un calibrador acústic de neutrins funcional. Finalment, cal ressenyar que he participat en les diferents investigacions i activitats que es descriuen en la tesi, sent la meua comesa principal el desenvolupament tant de l'electrònica com dels diferents softwares/firmwares implicats en els emissors acústics desenvolupats.Llorens Alvarez, CD. (2017). Diseño y desarrollo de la electrónica de los emisores acústicos para los sistemas de posicionamiento y calibración de telescopios submarinos de neutrinos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/88401TESISCompendi

Sistema de Transceptores de Ultrasonidos para triangulación acústica en el telescopio de Neutrinos KM3NeT

Recientemente se están empezando a desarrollar los telescopios de neutrinos, el objetivo principal de dichos telescopios es el de detectar flujos de neutrinos provenientes de eventos cósmicos de gran energía. Para lograr detectar dichos neutrinos y poder calcular su procedencia es necesario implementar arrays de foto-detectores de gran tamaño, para que la información de dicho array sea valida es necesario conocer en todo momento la posición de dichos foto-detectores con la mayor precisión posible. Es en este punto donde surge la necesidad de desarrollar un emisor de ultrasonidos potente y versátil. Para ello se han desarrollado una serie de prototipos para intentar alcanzar el objetivo propuesto con la mayor precisión posible. Básicamente, el prototipo debe de ser capaz de enviar una señal "de casi 1000 vpp" arbitraria comprendida entre 20 y 40 Khz al recibir una señal de "trigger" y todo ello con una alimentación de [email protected] Alvarez, CD. (2009). Sistema de Transceptores de Ultrasonidos para triangulación acústica en el telescopio de Neutrinos KM3NeT. Universitat Politècnica de València. http://hdl.handle.net/10251/8889Archivo delegad

Desarrollo de un emisor de ultrasonidos para posicionar el telescopios de neutrinos KM3Net

Recientemente se están empezando a desarrollar los telescopios de neutrinos, el objetivo principal de dichos telescopios es el de detectar flujos de neutrinos provenientes de eventos cósmicos de gran energía. Para lograr detectar dichos neutrinos y poder calcular su procedencia es necesario implementar arrays de foto-multiplicadores de gran tamaño en un medio transparente a gran profundidad (por ejemplo en el mar). Para que la información de dicho array sea válida es necesario conocer en todo momento la posición de dichos foto-multiplicadores. Es en este punto donde surge la necesidad de desarrollar un sistema de posicionamiento acústico. En este proyecto se trata el desarrollo de un emisor de ultrasonidos potente y versátil que sirva para dicho propósito. Para ello se han desarrollado una serie de prototipos para intentar alcanzar el objetivo de la forma más eficiente y con la precisión requerida (del orden del cm sobre distancias del orden del km). Básicamente, el prototipo debe de ser capaz de generar una señal de casi 800 vpp arbitraria comprendida entre 20 y 40 Khz al recibir una señal de trigger y todo ello con un consumo muy bajo, menor de 1W. Recently, underwater neutrino telescopes are being developed. The main objective of these telescopes is to detect neutrino fluxes from high-energy cosmic events. To detect these neutrinos and observe its origin, it is necessary to implement arrays of photo-multipliers of large size in a transparent medium, such as deep sea. To acquire valid information from this array we need to know the position of such photo-multipliers with a good accuracy. For this purpose, we need to develop an acoustic positioning system. This work is about the development of a versatile and powerful ultrasound emitter (transceiver) for this system. In order to do this, we have developed a series of prototypes, which basically is able to feed the acoustic transducer with arbitrary signals of almost 800 Vpp in the 20 - 40 kHz frequency range driven by a synchronous trigger signal, and all with a limited power consumption (less than 1 W).Llorens Alvarez, CD. (2011). Desarrollo de un emisor de ultrasonidos para posicionar el telescopios de neutrinos KM3Net. Universitat Politècnica de València. http://hdl.handle.net/10251/14607Archivo delegad

Acoustic parametric techniques for neutrino telescopes

[EN] In this work, we present a compact transmitter array based on the parametric acoustic sources effect able to reproduce the acoustic signature of an Ultra-High Energy neutrino interaction in water. We also propose to use directive transducers using the parametric technique for the characterization of piezo-ceramic sensors contained in the KM3NeT DOMs. This technique can minimize the need for an anechoic tank.Ardid Ramírez, M.; Tortosa, DD.; Llorens Alvarez, CD.; Martínez Mora, JA.; Saldaña-Coscollar, M. (2019). Acoustic parametric techniques for neutrino telescopes. EPJ Web of Conferences (Online). 216:1-3. https://doi.org/10.1051/epjconf/201921604001S13216Saldana M., PhD Thesis, Acoustic System Development for Neutrino Underwater Detectors. Gandia: Universitat Politecnica de Valencia (2017)Buis E.J.; et al. Characterization of the KM3NeT hydrophone. ARENA2018 this issue

Underwater Communication Using Acoustic Parametric Arrays

[EN] This paper presents a study of different types of parametric signals with application to submarine acoustic telecommunications. In all of them, the carrier frequency is 200 kHz, which corresponds to that resonation of the transducer under study, while they differ by the different modulations they present. In this sense, we study modulations with sweeps (4 to 40 kHz), in which represent binary codes (zeros and ones), getting closer to the application in acoustic telecommunications. The different properties of the transmitting signals in terms of communication speed, directivity, efficiency and power needed are discussed as well.We acknowledge the financial support of Plan Estatal de Investigación, ref. FPA2015-65150-C3-2-P (MINECO/FEDER), and of the Generalitat Valenciana, Grant PrometeoII/2014/079.Ardid Ramírez, M.; Campo-Valera, MM.; Tortosa, DD.; Felis-Enguix, I.; Llorens Alvarez, CD.; Martínez Mora, JA. (2018). Underwater Communication Using Acoustic Parametric Arrays. Proceedings. 2(139):1-7. https://doi.org/10.3390/ecsa-4-04907S17213

Acoustic signal detection through the cross-correlation method in experiments with different signal to noise ratio and reverberation conditions

[EN] The study and application of signal detection techniques based on cross-correlation method for acoustic transient signals in noisy and reverberant environments are presented. These techniques are shown to provide high signal to noise ratio, good signal discernment from very close echoes and accurate detection of signal arrival time. The proposed methodology has been tested on different signal to noise ratio and reverberation conditions using real data collected in several experiences related to acoustic systems in astroparticle detectors. This work focuses on the acoustic detection applied to tasks of positioning in underwater structures and calibration such those as ANTARES and KM3NeT deep-sea neutrino telescopes, as well as, in particle detection through acoustic events for the COUPP/PICO detectors. Moreover, a method for obtaining the real amplitude of the signal in time (voltage) by using cross correlation has been developed and tested and is described in this work.This work has been supported by the Ministerio de Economía y Competitividad (Spanish Government), project ref. FPA2012-37528-C02-02 and Multidark (CSD2009-00064). It has also being funded by Generalitat Valenciana, Prometeo/2009/26, and ACOMP/2014/153. Thanks to the ANTARES Collaboration for the help in the measurements made in the ANTARES deep-sea neutrino telescope.Adrián Martínez, S.; Bou Cabo, M.; Felis, I.; Llorens Alvarez, CD.; Martínez Mora, JA.; Saldaña, M.; Ardid Ramírez, M. (2015). Acoustic signal detection through the cross-correlation method in experiments with different signal to noise ratio and reverberation conditions. Lecture Notes in Computer Science. 8629:66-79. https://doi.org/10.1007/978-3-662-46338-3_7S66798629Ageron, M., et al. (ANTARES Collaboration): ANTARES: the first undersea neutrino telescope. Nucl. Instr. Meth. A 656, 11–38 (2011)The KM3NeT Collaboration: KM3NeT technical design report (2010). ISBN 978-90-6488-033-9. www.km3net.orgBehnke, E., et al. (COUPP Collaboration): First dark matter search results from a 4-kg CF3I bubble chamber operated in a deep underground site. Phys. Rev. D 86, 052001 (2012)Ardid, M.: Positioning system of the ANTARES neutrino telescope. Nucl. Instr. Meth. A 602, 174–176 (2009)Larosa, G., Ardid, M.: KM3NeT acoustic position calibration of the KM3NeT neutrino telescope. Nucl. Instr. Meth. A 718, 502–503 (2013)Ardid, M.: ANTARES: an underwater network of sensors for neutrino astronomy and deep-sea research. Ad Hoc Sensor Wirel. Netw. 8, 21–34 (2009)Bou-Cabo, M., Ardid, M., Felis, I.: Acoustic studies for alpha background rejection in dark matter bubble chamber detectors. In: Proceedings of the IV International Workshop in Low Radioactivity Techniques. AIP Conference Proceedings, vol. 1549, pp. 142–147 (2013)Proakis, J.G., Manolakis, D.G.: Digital Signal Processing, 3rd edn. Prentice Hall, Upper Saddle River (1996)Saldaña, M.: Acoustic system development for the underwater neutrino telescope positioning KM3NeT, Bienal de Física (2013)Ardid, M., et al.: Acoustic transmitters for underwater neutrino telescopes. Sensors 12, 4113–4132 (2012)Felis, I., Bou-Cabo, M., Ardid, M.: Sistemas acústicos para la detección de Materia Oscura, Bienal de Física (2013)Llorens, C.D., et al.: The sound emission board of the KM3NeT acoustic positioning system. J. Instrum. 7, C01001 (2012)Graf, K.: Experimental studies within ANTARES towards acoustic detection of ultra high energy neutrinos in the deep sea. Ph.D. thesis, U. Erlangen, FAU-PI1-DISS-08-001 (2008

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

Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search

[EN] The KM3NeT research infrastructure is uncon- struction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi- purpose neutrino detectors, ARCA and ORCA, primar-ily aimed at GeV¿PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time imple- mentation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially signifi- cant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems, are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the cur-rent detector capabilities and a report after the first two years of operation are given.The authors acknowledge the financial support of the funding agencies: Agence Nationale de la Recherche (contract ANR-15-CE31-0020), Centre National de la Recherche Scientifique (CNRS), Commission Europeenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX-0001), Paris ile-de-France Region, France; Shota Rustaveli National Science Foundation of Georgia (SRNSFG, FR-18-1268), Georgia; Deutsche Forschungsgemeinschaft (DFG), Germany; The General Secretariat of Research and Technology (GSRT), Greece; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell'Universita e della Ricerca (MIUR), PRIN 2017 program (Grant NAT-NET 2017W4HA7S) Italy; Ministry of Higher Education Scientific Research and Professional Training, ICTP through Grant AF-13, Morocco; Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO), the Netherlands; The National Science Centre, Poland (2015/18/E/ST2/00758); National Authority for Scientific Research (ANCS), Romania; Ministerio de Ciencia, Innovacion, Investigacion y Universidades (MCIU): Programa Estatal de Generacion de Conocimiento (refs. PGC2018-096663-B-C41, -A-C42, -B-C43, -B-C44) (MCIU/FEDER), Generalitat Valenciana: Prometeo (PROMETEO/2020/019), Grisolia (ref. GRISOLIA/2018/119) and GenT (refs. CIDEGENT/2018/034, /2019/043, /2020/049) programs, Junta de Andalucia (ref. A-FQM-053-UGR18), La Caixa Foundation (ref. LCF/BQ/IN17/11620019), EU: MSC program (ref. 101025085), Spain.Aiello, S.; Albert, A.; Alshamsi, M.; Alves Garre, S.; Aly, Z.; Ambrosone, A.; Ameli, F.... (2022). Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search. The European Physical Journal C. 82(4):1-16. https://doi.org/10.1140/epjc/s10052-022-10137-y11682

Nanobeacon: A time calibration device for the KM3NeT neutrino telescope

[EN] The KM3NeT Collaboration is currently constructing a multi-site high-energy neutrino telescope in the Mediterranean Sea consisting of matrices of pressure-resistant glass spheres, each holding a set of 31 small-area photomultipliers. The main goals of the telescope are the observation of neutrino sources in the Universe and the measurement of the neutrino oscillation parameters with atmospheric neutrinos. A relative time synchronisation between photomultipliers of the nanosecond arder needed to guarantee the required angular resolution of the detector. Due to the large detector volumes to be instrumented by KM3NeT, a cost reduction of the different systems is a priority. To this end, the inexpensive Nanobeacon has been designed and developed by the KM3NeT Collaboration to be used for detector time-calibration studies. At present, more than 600 Nanobeacons have been already produced. The characterisation of the optical pulse and the wavelength emission profile of the devices is critica! for the time calibration. The optical pulse rise time has been quantified as less than 3 ns, while the Full Width Half Maximum is less than 6 ns. The wavelength drift, due to a variation of the supply voltage, has also been qualified as lower than 10 nm for the full range of the Nanobeacon. In this paper, more details about the main features of the Nanobeacon design, production and operation, together with the main properties of the light pulse generated are described.The authors acknowledge the financial support of the funding agencies: Agence Nationale de la Recherche (contract ANR-15-CE31-0020), Centre National de la Recherche Scientifique (CNRS), Commission Europeenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX-0001), Paris Ile-de-France Region, France; Shota Rustaveli National Science Foundation of Georgia (SRNSFG, FR-18-1268), Georgia; Deutsche Forschungsgemeinschaft (DFG), Germany; The General Secretariat of Research and Technology (GSRT), Greece; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell'Universita e della Ricerca (MIUR), PRIN 2017 program (Grant NAT-NET 2017W4HA7S) Italy; Ministry of Higher Education Scientific Research and Professional Training, ICTP through Grant AF-13, Morocco; Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO), the Netherlands; The National Science Centre, Poland (2015/18/E/ST2/00758); National Authority for Scientific Research (ANCS), Romania; Ministerio de Ciencia, Innovacion, Investigacion.. Universidades (MCIU): Programa Estatal de Generacion de Conocimiento (refs. PGC2018-096663-B-C41, -A-C42, -B-C43, -B-C44) (MCIU/FEDER), Generalitat Valenciana: Prometeo (PROMETEO/2020/019), Grisolia (ref. GRISOLIA/2018/119) and GenT (refs. CIDEGENT/2018/034,/2019/043,/2020/049) programs, Junta de Andalucia (ref. A-FQM-053-UGR18), La Caixa Foundation (ref. LCF/BQ/IN17/11620019), EU: MSC program (ref. 101025085), Spain.Aiello, S.; Albert, A.; Alshamsi, M.; Alves Garre, S.; Aly, Z.; Ambrosone, A.; Ameli, F.... (2022). Nanobeacon: A time calibration device for the KM3NeT neutrino telescope. Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment. 1040:1-13. https://doi.org/10.1016/j.nima.2022.167132113104

The KM3NeT multi-PMT optical module

[EN] The optical module of the KM3NeT neutrino telescope is an innovative multi-faceted large area photodetection module. It contains 31 three-inch photomultiplier tubes in a single 0.44 m diameter pressure-resistant glass sphere. The module is a sensory device also comprising calibration instruments and electronics for power, readout and data acquisition. It is capped with a breakout-box with electronics for connection to an electro-optical cable for power and long-distance communication to the onshore control station. The design of the module was qualified for the first time in the deep sea in 2013. Since then, the technology has been further improved to meet requirements of scalability, cost-effectiveness and high reliability. The module features a sub-nanosecond timing accuracy and a dynamic range allowing the measurement of a single photon up to a cascade of thousands of photons, suited for the measurement of the Cherenkov radiation induced in water by secondary particles from interactions of neutrinos with energies in the range of GeV to PeV. A distributed production model has been implemented for the delivery of more than 6000 modules in the coming few years with an average production rate of more than 100 modules per month. In this paper a review is presented of the design of the multi-PMT KM3NeT optical module with a proven effective background suppression and signal recognition and sensitivity to the incoming direction of photons.The authors acknowledge the financial support of the funding agencies: Agence Nationale de la Recherche (contract ANR-15-CE31-0020), Centre National de la Recherche Scientifique (CNRS), Commission Européenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX-0001), Paris Île-de-France Region, France; Shota Rustaveli National Science Foundation of Georgia (SRNSFG, FR-18- 1268), Georgia; Deutsche Forschungsgemeinschaft (DFG), Germany; The General Secretariat of Research and Technology (GSRT), Greece; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell¿Università e della Ricerca (MIUR), PRIN 2017 program (Grant NAT-NET 2017W4HA7S) Italy; Ministry of Higher Education, Scientific Research and Innovation, Morocco, and the Arab Fund for Economic and Social Development, Kuwait; Nederlandse organisatie voor Wetenschappel¿k Onderzoek (NWO), the Netherlands; The National Science Centre, Poland (2015/18/E/ST2/00758); National Authority for Scientific Research (ANCS), Romania; Ministerio de Ciencia, Innovación, Investigación y Universidades (MCIU): Programa Estatal de Generación de Conocimiento (refs. PGC2018-096663- B-C41,-A C42,-B-C43,-B-C44) (MCIU/FEDER), Generalitat Valenciana: Prometeo (PROMETEO/2020/019), Grisolía (refs. GRISOLIA/2018/119,/2021/192) and GenT (refs. CIDEGENT/2018/034, /2019/043,/2020/049,/2021/023) programs, Junta de Andalucía (ref. AFQM-053-UGR18), La Caixa Foundation (ref. LCF/BQ/IN17/11620019), EU: MSC program (ref. 101025085), Spain.Aiello, S.; Albert, A.; Alshamsi, M.; Alves Garre, S.; Aly, Z.; Ambrosone, A.; Ameli, F.... (2022). The KM3NeT multi-PMT optical module. Journal of Instrumentation. 17:1-23. https://doi.org/10.1088/1748-0221/17/07/P070381231