Frontier Detectors for Frontier Physics 11 th Pisa

Frontier Detectors for Frontier Physics 11 th Pisa meeting on advanced detectors 2009 A PROTOTYPE FOR THE ACOUSTIC TRIANGULATION SYSTEM OF THE KM 3 NET DEEP SEA NEUTRINO TELESCOPE M. Ardid, M. Bou-Cabo, F. Camarena, V. Espinosa, G. Larosa, C. D. Llorens-Álvarez, J. Martínez-Mora, for the KM 3 Ne. T Consortium Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres - Universitat Politècnica de València Introduction The KM 3 Ne. T project aims at the construction and operation of a cubic-kilometre scale neutrino telescope in the Mediterranean Sea. Study of the prototype for the acoustic positioning system Good specifications of FFR hydrophones for this application. The KM 3 Ne. T telescope consists of an array of optical modules (photon sensors contained in glass sphere vessels) which detect Cherenkov light from muon tracks. The optical modules are subject to motion in the presence of deep sea currents. An acoustic triangulation system is needed to determine their positions, so as to provide the tracking precision and angular resolution required for astronomical neutrino source searches. Figure 3: Tests on FFR hydrophones measuring the Transmitting and Receiving Voltage Responses @ UPV Gandia. Hydrophones withstand high pressures. Figure 1: Example of underwater acoustic triangulation. Prototype for the acoustic positioning system One of the solutions proposed for the acoustic system for KM 3 Ne. T is a system consisting of an array of affordable transducers that can operate as transceivers (emitterreceivers) in the 20 -40 k. Hz region and withstand the high pressures (up to 500 bar). One versatile electronic acoustic board using lowpower components has been developed, implementing the acoustic DAQ in the all-data-to-shore approach. Figure 4: Test on FFR hydrophone at the high pressure in hyperbaric tank @ IFREMER Brest. The system (electronics + FFR sensors) is being tested nowadays. emitted signal received signal Figure 5: Tests on FFR hydrophone with the control of the electronic acoustic board @ UPV Gandia. Figure 2: FFR (Free Flooded Ring) hydrophone and electronic acoustic board for the control of the emitted and received signals used for the prototype of the acoustic positioning system. The system will be tested in deep water next year as part of a KM 3 Ne. T prototype.