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Latest Results with the Acoustic Modules of the AMADEUS Acoustic System in ANTARES. T. Eberl for Robert Lahmann and the Erlangen acoustic group KM3NeT WP2,3,4,5 joint meeting Paris, 23-Feb-2009. The AMADEUS Project.
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Latest Results with the Acoustic Modules of the AMADEUS Acoustic System in ANTARES T. Eberl for Robert Lahmannand the Erlangen acoustic group KM3NeT WP2,3,4,5 joint meeting Paris, 23-Feb-2009
The AMADEUS Project The AMADEUS project extends the ANTARES detector by a dedicated array of acoustic sensors The main goal is the investigation of techniques for acoustic particle detection The system can be used as a multiple purpose device (studies of neutrino detection, marine science, positioning,…) For more details: Webpage of the AMADEUS project: http://www.acoustics.physik.uni-erlangen.de Presentation from last WP3 meeting (Paris 18-Oct-2008): http://agenda.infn.it/conferenceDisplay.py?confId=822
The AMADEUS System • Taking data since 5-Dec-2007 • Completely installed since 30-May-2008 • Acoustics on L12: Data from 6-Sep to 24-Dec-2008 “Pingers“ (acoustic RxTx) on each Anchor
Features of AMADEUS • 30 hydrophones: 28/30 working • 3 Acoustic Modules (6 acoustic sensors): all working • Typical sensitivity of hydrophones: -145 dB re. 1V/Pa(including preamplifier) • 16-bit digitization @ 250 kSps (1~100 kHz bandwidth) • Amplification of analogue signal from 1 to 562 • All data to shore (but off-shore pre-trigger possible) • Triggered data (on-shore) ~15 GByte/day(Data reduction by factor of ~100) • Continuous data taking with (currently) >80% uptime(not counting failure of sector on L12)
Acoustic Modules (AMs) Piezo sensors + preamplifiers Design allows for integration of acoustic sensors into pressure housing of photo sensors No need for additional mechanical structures
Positioning Option for KM3NeT • AMADEUS-like acoustic sensors have the potential to combine: • positioning • investigation of acoustic neutrino detection techniques • marine science • The Acoustic Modules (AMs) allow for an integration of acoustic sensors into Optical Modules. • Are piezo elements within a PMT housing an inexpensive option for a multi purpose acoustic system for KM3NeT? • Many answers can be given by investigating AM performance! • This presentation: Only results with AMs
Methods for Position Reconstructiongoal: positioning at cm-level(4s sampling ≙ 6mm) • Main Method – using database info about emission time of pinger signals • positioning of individual sensors • use absolute time for the 14 pingers: cs (treception – temission – toffset ) Trigger on firstnegative peak,… …Zero crossing defines treception
Position Reconstruction for Acoustic Modules Same method for AMs, but distortion of signal due to interferences in glass sphere; Apply trigger threshold on envelope
Resolution of Position Reconstruction for AMs Calculate difference of individually reconstructed sensor position Systematic effects due to orientation of sensors w.r.t. pingers need to be investigated
Measurement of Heading with Acoustic Modules I Fit known positions of sensors in coordinate system of the storey to the reconstructed positions
Measurement of Heading with Acoustic Modules II Systematic effects due to orientation of sensors w.r.t. pingers need to be investigated
Acoustic Modules for KM3NeT? • Principle Design is applicable and easily adaptable. • Some questions need to be addressed with lab measurements: • Precision or reconstruction for acoustic sensors in one module • How many sensors per module are needed? • Effect of HV of PMTs in same module
Conclusions • AMADEUS performance is excellent • The AMADEUS system has all features of an acoustic neutrino telescope (except size) • Can be used as a multi purpose device (studies of neutrino detection, marine science, positioning,…) • “Acoustic Modules” are an option for acoustic measurements without additional mechanical structures for KM3Net • AMADEUS design flexible: adaptable to KM3NeT design and DAQ hardware • As option for KM3NeT: More studies with AMADEUS and in laboratory required Funded by:
Goals of the AMADEUS Project • Feasibility study for future large scale acoustic detector • Background investigations (rate of neutrino-like signals, localisation of sources) • Investigation of signal correlations on different length scales • Tests of different hydrophones and sensing methods • Development and tests of filter and reconstruction algorithms • Studies of hybrid detection methods
~10cm Setup of Acoustic Storey with Hydrophones Hydrophone:Piezo sensorwith pre-amplifierand band pass filter in PU coating Titanium cylinderwith electronics 3 custom designed Acoustic ADC boards
Pinger Signals for Reconstruction of Hydrophones and AMs AMs Hydros
Characteristics of the Acoustic ADC boards 3 Acoustic ADC boards (AcouADC boards) used per storey, each processing 2 sensors • 16 bit digitisation (-2V to +2V) • Bandwidth up to ~125 kHz • Adjustable digitisation rate, max. 500 kSamples/s(Currently using downsampling 2: 250 kSamples/s transmitted to shore, i.e. 3MByte/s for 6 hydrophones) • System extremely flexible due to use of FPGA off-shore (downsampling, adjustable gain 1 to 562, off-shore firmware updates possible)