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Status and First Results of the Acoustic Detection System AMADEUS in ANTARES

Status and First Results of the Acoustic Detection System AMADEUS in ANTARES. Robert Lahmann for the ANTARES Collaboration ARENA 08, Rome, 26-June-2008. Outline. Overview of AMADEUS Technical implementation of AMADEUS First results Conclusions. Overview of AMADEUS. . hadronic cascade.

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Status and First Results of the Acoustic Detection System AMADEUS in ANTARES

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  1. Status and First Results of the Acoustic Detection System AMADEUS in ANTARES Robert Lahmann for the ANTARES Collaboration ARENA 08, Rome, 26-June-2008

  2. Outline Overview of AMADEUS Technical implementation of AMADEUS First results Conclusions

  3. Overview of AMADEUS

  4. hadronic cascade ≈10m ≈1km Expect detection threshold E > 1018 eV (1 EeV) ~ Reminder: Acoustic Signals from Neutrinos Temperature Instantaneous heating, followed by slow cooling Ecasc= 1 EeV @ 1km Adapted from arxiv/0704.1025v1 (Acorne Coll.)

  5. Acoustic Background in the Sea Random noise Neutrino-like events A Bipolar Pressure Signals (BIPs) Have to measure correlated BIP rate: Adapted fr. astro-ph/0104033 (Lehtinen et al.)‏ • Hydrophone array required • Hydrophone synchronisation crucial • One Hydrophone in principle sufficient • Hydrophone synchronisation not crucial

  6. 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

  7. The Acoustic Detection System AMADEUS Concept: Local clusters at large distances • 6 Hydrophones on 1m scale: • Local coincidences for suppression of uncorrelated background • Reconstruct direction of source • 6 clusters with a total of 36 sensors • Spacings between clusters from 15m to 340m

  8. The AMADEUS System • Taking data since 5-Dec-2007 • Completely installed since 30-May-2008

  9. Overview of Acoustic Sensors • 19 commercial hydrophones: all working • 11 self-made hydrophones: 9/11 working • 3 Acoustic Modules (6 acoustic sensors): all working • 34/36 sensors working in total • Typical sensitivity of hydrophones: -145 dB re. 1V/Pa

  10. Technical Implementation of AMADEUS

  11. Features of AMADEUS • Full detector capabilities (time synchronisation, DAQ,…) • Combines local clusters of acoustic sensors with large cluster spacing • Designed to make use of standard ANTARES hard- and software as much as possible • All data to shore (but off-shore pre-trigger possible) • Triggered data (on-shore) ~10 GByte/day • Continuous data taking with (currently) ~80% uptime

  12. AMADEUS Uptime takeover of sector control DB problems ANTARES completed! deployment L11 and L12

  13. ~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

  14. 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)

  15. System Response Function Hydrophone (piezo+preamp) Filter (analog+digital), amplifier System response measured in lab prior to deployment for each individual component

  16. frequency domain dB (V/V) transfer spectrum (raw)‏ dB re 1µPa/V sender dBre 1V/µPa corrected sensitivity characteristics frequency (kHz) log frequency (kHz) Hydrophone Sensitivity Measurement - Principles voltage pulse sent amplitude (V) log frequency (kHz) received time(µs)

  17. Directional Calibration of Hydrophones  - Freq sensitivity   - freq sensitivity Sensitivity measured with calibrated hydrophone, confirmed with reciprocity method In-situ measurements planned

  18. 20 10 0 -60 -80 -100 PSD (dB re 1V2/Hz)‏ Phase (rad)‏ 0 100 200 Frequency (kHz) 0 100 200 Frequency (kHz) Calibration of AcouADC board • Calibration of : Amplification, non-linearities, frequency response, … • System functions parameterised Excellent system stability, fluctuations at %-level

  19. Signal Response of AcouADC Board Very good agreement between real and modelled system response

  20. The Acoustic DAQ System

  21. The Onshore Filter System Task:Reduce incoming data rate of ~1.6 TByte/day to ~10 GByte/day System extremely flexible, all components scalable Allows for coincidence triggers on several hydrophones Local clusters (storeys) big advantage for fast (on-line) processing Acoustic servers: 4 servers in total, 2 for filtering: 2 Dualcore,3 GHz 2 Quadcore, 3 GHz Details in talk by M. Neff

  22. First Results

  23. Correlation with Weather Conditions Hydrophone noise integrated from 1 to 50 kHz Windspeed (kt): Mean=9.4 kt preliminary preliminary (mPa) Weather conditions measured at Hyères airport, about 30km north of ANTARES site • Correlation coefficient ~ 80% • Deep-sea noise dominated by sea surface agitation

  24. Power Spectral Density of Background Noise Data from two month: preliminary Lab measurement Observed background noise in deep sea basically as expected

  25. Noise distribution in dependence of wind speed Exemplary 10s-slices preliminary

  26. Pinger of ANTARES Positioning System (I)‏ Pinger of ANTARESpositioning systemare also used for positioning of acoustic storeys(work in progress)

  27. Pinger of ANTARES Positioning System (II)‏ • Pinger signal: • Amplitude reduced with distance • Temporal structure (1st and 2nd ping originate from different positions)

  28. Pinger Signals: Comparison of AMs and Hydrophones AMs Hydros

  29. Localisation of Transient Signals Reconstruction of sourcedistance with triangulationfrom several storeys Most probabledirection of source Details in talk by C. Richardt

  30. 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, positioning,…) • “Acoustic Modules” are an option for acoustic measurements without additional mechanical structures Funded by:

  31. Backup Transparencies

  32. Acoustic Storeys on Line 12 Deployment May 2008 Storey 21 (3 “Acoustic Modules”, 6 sensors in total) Storey 22 (6 commercial sensors)‏ Storey 23 (6 sensors produced at Erlangen)

  33. Acoustic Storeys on the IL07 Deployment July 2007 Storey 2 (6 commercial sensors) Storey 3 (6 sensors produced at Erlangen) Storey 6 (6 commercial sensors)

  34. Acoustic Modules Piezo sensors + preamplifiers Design allows for integration of acoustic sensors into pressure housing of photo sensors  No need for additional mechanical structures

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