A Compact Array Transducer for Full Calibration of Underwater Acoustic Detection Neutrino Telescopes

[EN] KM3NeT, the underwater neutrino telescope in the Mediterranean Sea, is a detector under construction. KM3NeT uses Digital Optical Modules (DOMs) to detect neutrinos but there will be a study about the viability to acoustic detection of neutrinos using mainly the acoustic sensors the telescope has for positioning purposes. For this, it is necessary to calibrate and test the acoustic response of the receivers in the detector to determine the sensitivity to detect the neutrino acoustic signal and discriminate it from the environmental background. In this work, the strategy for the calibration of the sensor system using a compact array using three steps (frequency, directivity and neutrino signal-like) is described. Moreover, some R&D activities and results about the second step (long parametric directive signals) are shown.Financial support of the Spanish Plan Estatal de Investigación, ref. PGC2018-096663-B-C43 (MICINN/FEDER)Ardid Ramírez, M.; Tortosa, DD.; Martínez Mora, JA. (2019). A Compact Array Transducer for Full Calibration of Underwater Acoustic Detection Neutrino Telescopes. IEEE. 591-595. https://doi.org/10.1109/IOTSMS48152.2019.8939244S59159

Reconciling coherent oscillation with modulation of irregular spiking activity in selective attention: gamma-range synchronization between sensory and executive cortical areas

[EN] In this computational work, we investigated gamma-band synchronization across cortical circuits associated with selective attention. The model explicitly instantiates a reciprocally connected loop of spiking neurons between a sensory-type (area MT) and an executive-type (prefrontal/parietal) cortical circuit (the source area for top-down attentional signaling). Moreover, unlike models in which neurons behave as clock-like oscillators, in our model single-cell firing is highly irregular (close to Poisson), while local field potential exhibits a population rhythm. In this "sparsely synchronized oscillation" regime, the model reproduces and clarifies multiple observations from behaving animals. Top-down attentional inputs have a profound effect on network oscillatory dynamics while only modestly affecting single-neuron spiking statistics. In addition, attentional synchrony modulations are highly selective: interareal neuronal coherence occurs only when there is a close match between the preferred feature of neurons, the attended feature, and the presented stimulus, a prediction that is experimentally testable. When interareal coherence was abolished, attention-induced gain modulations of sensory neurons were slightly reduced. Therefore, our model reconciles the rate and synchronization effects, and suggests that interareal coherence contributes to large-scale neuronal computation in the brain through modest enhancement of rate modulations as well as a pronounced attention-specific enhancement of neural synchrony.This work was funded by the Volkswagen Foundation, the Spanish Ministry of Science and Innovation, and the European Regional Development Fund. A.C. is supported by the Researcher Stabilization Program of the Health Department of the Generalitat de Catalunya. X.-J.W. is supported by the National Institutes of Health Grant 2R01MH062349 and the Kavli Foundation. We are thankful to Stefan Treue for fruitful discussions and to Jorge Ejarque for technical support in efficiently implementing the search optimization procedure in a grid cluster computing system. Also, we thankfully acknowledge the computer resources and assistance from the Barcelona Supercomputing Center-Centro Nacional de Supercomputación, Spain.Ardid-Ramírez, JS.; Wang, X.; Gomez-Cabrero, D.; Compte, A. (2010). Reconciling coherent oscillation with modulation of irregular spiking activity in selective attention: gamma-range synchronization between sensory and executive cortical areas. Journal of Neuroscience. 30(8):2856-2870. https://doi.org/10.1523/JNEUROSCI.4222-09.2010S2856287030

Development of a trigger for acoustic neutrino candidates in KM3NeT

The KM3NeT Collaboration is constructing two large neutrino detectors in the Mediterranean Sea: ARCA, located near Sicily and aiming at neutrino astronomy, and ORCA located near Toulon and designed for the study of intrinsic neutrino properties. The two detectors together will have hundreds of Detection Units with Digital Optical Modules kept vertically by buoyancy forming a large 3D optical array for detecting the Cherenkov light produced after the neutrino interactions. To properly reconstruct the direction of the incoming neutrino, the position of the DOMs, which are not static due to the sea currents, must be monitored. For this purpose, the detector is equipped with an Acoustic Positioning System, which is composed of fixed acoustic emitters on the sea bottom, a hydrophone in each DU base, and a piezoceramic sensor in each DOM, as acoustic receivers. This network of acoustic sensors can be used not only for positioning, but also for acoustic monitoring studies such as bioacoustics, ship noise monitoring, environmental noise control, and acoustic neutrinos detection. This work explores the possibility of creating a trigger for saving the data for ultra-high-energy neutrino candidates detected acoustically by the hydrophones. The acoustic signal caused by the neutrino interaction in a fluid is a short-time duration Bipolar Pulse extremely directive and with a Fourier transform extending over a wide range of frequencies. A study of signal detection, has been done by simulating BP produced by the interaction of a UHE neutrino at 1 km from the detector at zero-degree incidence added to the experimental real acoustic data. Finally, a trigger proposal has been developed in order to record candidates of BPs and it has been tested. The number of candidates per second, precision, and recall have been monitored according to the cuts applied and parameters calculated by the algorithm.Comment: 9th International Workshop on Acoustic and Radio EeV Neutrino Detection Activities - ARENA202

Underwater Acoustic Positioning System for the Monitoring of KM3NeT Optical Modules

[EN] KM3NeT, the underwater neutrino telescope in the Mediterranean Sea, is a detector under construction. KM3NeT uses Digital Optical Modules (DOMs) to detect neutrinos by detecting the Cherenkov light of relativistic particles produced in the interaction. To reconstruct the neutrino event and the coming direction, it is necessary to monitor the position of each DOM, which is not fixed since it is mounted in flexible string lines, held close to vertical by buoys but sensitive to sea currents. A piezo-ceramic transducer is installed inside of each DOM. Using some emitters anchored in the sea floor it is possible to calculate the position of the DOMs by triangulation of distances obtained from the determination of the time of flight of the acoustic wave. In this work, the acoustic model used for the simulation of the system is described and the results presented.[ES] KM3NeT, el detector submarino que se encuentra en construcción en el Mar Mediterráneo, usa Módulos Digitales Ópticos (DOMs) para localizar neutrinos, a través de la detección de la luz de Cherenkov producida por partículas relativistas durante la interacción con el agua. Para reconstruir el camino seguido por el neutrino, es necesario saber la posición de cada DOM, el cuál no se encuentra fijo ya que está sujeto a unos cables anclados que se mantienen en vertical gracias a una boya en el final de la línea, lo cual la hace sensible al movimiento de las corrientes marinas. Cada DOM contiene instalada una cerámica piezoeléctrica, como receptor acústico, y usando unos emisores anclados en el fondo del mar se puede estimar la posición de cada DOM triangulando las distancias entre ellos, las cuales se saben por el tiempo de vuelo de la señal acústica. En este trabajo, se presenta una simulación del sistema y se describe el modelo acústico usado.Ardid Ramírez, M.; Bou Cabo, M.; D. Tortosa, D.; Martínez Mora, JA.; Poirè, C. (2019). Underwater Acoustic Positioning System for the Monitoring of KM3NeT Optical Modules. Revista de Acústica. 50(3-4):24-33. http://hdl.handle.net/10251/160009S2433503-

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

Acoustic Transmitters for Underwater Neutrino Telescopes

In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters.Comment: 21 pages, 14 figures,1 tabl

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