New design of an acoustic array calibrator for underwater neutrino - PowerPoint PPT Presentation

2 nd International Electronic Conference on Sensors and Applications 15-30 November 2015 New design of an acoustic array calibrator for underwater neutrino telescopes M. Saldaña, C.D. Llorens, I.Felis, J. A. Martínez-Mora and M. Ardid UPV – IGIC – Campus de Gandia (València)

New design of an acoustic array calibrator for underwater neutrino telescopes Contents • Introduction • Acoustic Neutrino´s Signal • Need for a calibrator. Design Philosophy • Compact Calibrator. Parametric acoustic sources • Compact Array Calibrator design (under development) • Conceptual Design • Ceramic Characterization • Moulding • Parametric Generation Results • Electronics and functionalities • Summary • Future Steps

New design of an acoustic array calibrator for underwater neutrino telescopes Acoustic Neutrino’s Signal The Thermo-Acoustic Model Energy deposition when a neutrino Induces a local heating in a very short period of interacts with nuclei in water time leading to a short pressure pulse signal Temperature Deep Sea d 2 Time 2 dt Neutrino Telescope G.A.Askaryan . Hydrodynamical emission of tracks of ionising particles in stable liquids . J. At. Energy 3 (1957) 921. h ∆t • Bipolar Pulse 𝒊 ∝ 𝜷 𝜸 • Cylindrical Propagation 𝑫 𝒒 • Pancake Directivity ≈ 1º

New design of an acoustic array calibrator for underwater neutrino telescopes Need for a calibrator. Design Philosophy A good acoustic calibrator can be very important to study the feasibility of the UHE neutrino acoustic detection technique and help to discriminate the signal from noise and background of transient signals. Useful tool to: • Train and tune the acoustic detector • Help to classify signals: background of transient signals • Marine life and natural phenomena • Anthropogenic/technical origin • Perform in situ measurements of neutrino-like signals from a known source (Sea Campaigns or integrated in the infrastructure). • To verify the simulation results • To improve the signal classification algorithms • Monitor the individual sensors and assess the full detection system

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Calibrator. Parametric Acoustic Source Neutrino-like signals generation is achieved by using parametric acoustic sources • Parametric acoustic generation (Westervelt, 1963) is a non linear effect used in different underwater Primary Secondary Primary applications . f2=482 kHz f2-f1=64 kHz f1=418 kHz • Compact : possible to obtain directive low -frequency beams from 2 directive high-frequency beams • Bipolar transient pulse can be obtained from signal modulation • Since the signal has to travel long distances, primary high-frequency signal will be absorbed . • Main drawback: low-power conversion efficiency , usually less than 1%

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Conceptual Design New proposed design composed of an array of piezo ceramic tube transducers array emitting in axial direction Array composed of new piezo tube Processes involved in the design ceramics emitting in axial direction Characterization of piezo-ceramics • Ceramic Moulding (Heading/Backing) • Operation at high-frequency by the Array design • parametric technique Signal processing techniques • Simulations • New specific electronics adapted to the transducers Tests of the prototype •

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Characterization. System Characterization at the Laboratory water tank Two Piezo-Tube Ceramics under study UCE-343020 UCE-534541 OD=5.3 ID=4.5 H=4.1 [cm] OD=3.4 ID=3 H=2 [cm] Equipment for characterization Generator/Acquisitor NI PXI 1031 DC - LAbView Water Tank Receiver RESON TC4038 Amplifier [Freq Range 10kHz – 1MHz] Receiver Emitter

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Characterization. Characterization of piezo-ceramics Primary frequency of resonance is around 490 kHz and secondary resonance frequency at low frequency around 35 kHz. High frequency UCE-534541 Low frequency OD=5.3 ID=4.5 H=4.1 [cm]

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Characterization Characterization of piezo-ceramics Sensitivity of UCE-534541 -> 159 dB (re µPa/V at 1m) at F R =490 kHz with a directivity of ± 5º • Sensitivity of UCE-343020 -> 162 dB (re µPa/V at 1m) at F R =890 kHz with a directivity of ± 7º • The TVR at low frequency oscillates between 132 dB – 143 dB (re µPa/V at 1m). • Sensitivity (dB re uPa/V @1m) TVR Ceramic UCE Sensitivity (dB re uPa/V) Axial Directivity UCE Ceramic TVR Ceramic UCE Normalized amplitude 165 1 142 534541 140 343020 160 0.8 138 0.6 136 155 0.4 134 534541 534541 0.2 150 132 343020 343020 130 10 20 30 40 50 60 70 80 90100 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 -20 -10 0 10 20 Frequency (kHz) Frequency / Resonance Frequency Angle [º]

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Moulding First Tests for Ceramic Moulding (Heading/Backing) Moulding RoyaPox511 Resin Goal No Loses Ensuring protection • Holding • Isolating • Matching Impedance • Thickness matching accomplish λ/4 4-5 dB Loses Moulding Poliutherane EL241F of the wave length emitted at the ceramic resonance frequency Next  To Study the Effect on Parametric Emission

New design of an acoustic array calibrator for underwater neutrino telescopes Compact Array Calibrator. Parametric emission. First Studies of the Parametric Bipolar Pulse Emission Bipolar Shape Similar Directivity Non-Linearity Original Received Signal (blue) and Filtered Received Signal (red) Directivity Horizontal Received Signal Normalized amplitude Normalized Amplitude at low-frequency [5 kHz - 80 kHz] 1 Non-Filtered Original Received Signal Filtered 1 0.8 Filtered Amplitude(V) 2 Original 0.6 0.5 Filtered(x20) 0.4 0 0 0.2 0.2 0.4 0.6 0.8 1 -2 -6 -4 -2 0 2 4 6 Amplitude Input Signal(V) Angle [º] 0.7 0.72 0.74 Time(ms)  Low frequency beams with small transducer (High Frequency)  The viability of the technique  Able to reproduce acoustic neutrino’s directivity with few sources has been checked

New design of an acoustic array calibrator for underwater neutrino telescopes Electronics and Functionality  Transducer Matching Challenge: Detecting the  Signal Control and Generation High directivity Bipolar  Amplification pulse emitted from several km away Three Operation Modes Functionalities: Training and tuning the TAGGING the BIPOLAR acoustic detector, cross-checking the pulse emissions detector hydrophones Calibration in 3 Steps, increasing difficulty 1st Stage 2nd Stage 3rd Stage Low Frequency: High Frequency: HF: Emitting long non Emitting long Parametric Bipolar signal: directive signals parametric transient & directive Easy to detect directive signals

New design of an acoustic array calibrator for underwater neutrino telescopes Summary Both ceramics are optimal candidates for the neutrino´s calibrator. They • have a good sensitivity in both high and low frequency and narrow beam directivity at the high frequency which will lead to a tight low-frequency (parametric) directivity. Matching layer studies validate the materials for the ceramics covering . • Generation of acoustic neutrino’s -like signal has been achieved and • validated. By using parametric technique. New electronics are under development for achieving larger efficiency in • the high frequency emission. Future sea campaign foreseen for testing and using it. •

New design of an acoustic array calibrator for underwater neutrino telescopes Future steps • Array structure design and moulding • Final design of the electronics • Signal processing techniques • Simulations • Long distance tests of the prototype • In situ test at the telescopes AMADEUS/KM3NeT

New design of an acoustic array calibrator for underwater neutrino telescopes Thank you for the attention Acknowledgements: FPA2012-37528-C02-02, CSD2009-00064, PrometeoII/2014/079, ACOMP/2015/175