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An Acoustic Array in the United Kingdom. Chris Rhodes Naval Systems Department Defence Science and Technology Laboratory. UK Collaboration Dstl Sheffield University University College London University of Northumbria Lancaster University.
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An Acoustic Array in the United Kingdom Chris Rhodes Naval Systems Department Defence Science and Technology Laboratory
UK CollaborationDstlSheffield UniversityUniversity College LondonUniversity of NorthumbriaLancaster University
Sonar ModellingEstimate SL = 121dB re 1Pa @ 1mfor 1020 eV event.Highly directional……60dB down over most aspects.
Sonar ModellingAt Rona N typically 40-45dB over frequencies of interestTaking into account propagation losscould make reliable detections out to 2000m.
Sonar Modelling1016eV Butkevitch pulse cannot be detected at Rona.Estimate 50m for 1018eV event.Quieter locations would give a lower threshold for the acoustic technique.
Way Ahead - RecordingRecord 4 channels of data up to 80kHz from the mid-water measurement hydrophonesBuild an unattended digital recorder to gather 4 hydrophone-months of data
Way Ahead - CalibrationExperiment with pulse simulators:a) simple omni’s - system checkb) parametric technique - replicate beam pattern effectsc) wires, lasers…any crazy ideas!
OutputsBegin to build a capability in developing the acoustic technique.Understand the practicalities of recording challenging signal-types and attempting detectionExcellent understanding of local noise environment over long time-scaleMight even detect a neutrino!
Final ThoughtsApply for joint UK-MoD/PPARC fundingWe need to learn from experience gained so far with this technique
Last Final ThoughtsAssuming that the pulse-types calculated theoretically are accurate……acoustic detection is a tough proposition.Better to chase more abundant lower energy events…….need to squeeze more dBs out of the system! Either go to really deep water or use fields of line arrays with beamforming to exploit ambient noise anisotropy.