1. ANTARES: Towards Acoustic Detection of Highest Energy Neutrinos Kay Graf for the ANTARES Collaboration Erlangen Centre for Astroparticle Physics VLV T 09, Athens, Oct. 13 th – 15 th 2009

2. Outline Motivation The AMADEUS System Positioning Source Reconstruction Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 2

3. Motivation Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 3

4. Ultra-high Energy Neutrino Astrophysics at energies above 10 14-15 eV: universe becomes opaque to photons at Mpc range CR protons, nuclei are galactic up to ~10 18 eV, suffer GZK cut-off above that neutrinos unabsorbed at all energies → sources exist to at least 3x10 20 eV UHE neutrinos are the only viable messenger beyond the local universe Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 4 viable throughout these regions P. Gorham

5. Highest Energy Neutrinos astrophysics: origin of UHECR GZK neutrinos cosmology: top-down scenarios topological defects particle physics: neutrino cross section 5 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 log 10 (E[eV]) 16142418 TD 2022 T. Karg, arXiv:astro-ph/0608312 10 -4 10 -8 10 -6 10 -10 Flux × E 2 [eV m -2 s -1 sr -1 ] water/ice Cherenkov telescopes complementary techniques for GZK : >100km 2 ∙ 2  ∙ year detector needed

6. (U)HE Detection Methods Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 6 neutrino cascadecascade hydrophone array Acoustic Detection water, ice, salt att > 1km (water) sonic wave radio Cherenkov cascadecascade antenna array Radio Cherenkov ice, salt, rock att ~ 1km (ice)  optical Cherenkov PMT array Optical Cherenkov water, ice att < 100m balloon satellite telescope + hybrid detectors

7. Acoustic Signal Properties Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 7 E casc = 1 EeV @ 1km bipolar signal (~10kHz) with disk-like geometry Acorne Coll. astro-ph/0704.1025 peak pressure (mPa/EeV) T. Karg, astro-ph/0608312v1 log 10 (radial distance (m)) distance along shower axis (m) shower maximum log 10 (radial distance (m))

8. Simulations of an Acoustic Detector strong dependence: V eff (P thres ) P thres mainly given by ambient noise a threshold of 5mPa seems reachable in the deep-sea Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 8 T. Karg, arXiv:astro-ph/0608312 200 acoustic antennas/km 3 P thres

9. The AMADEUS System Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 9

10. The AMADEUS Project Feasibility Study detector environment (hybrid) detector calibration functionality sensor design and positioning background studies signal processing techniques integration of acoustic setup into the ANTARES neutrino telescope Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 10

11. The ANTARES Neutrino Telescope optical Cherenkov Telescope 875 PMT at 2500m water depth V inst ~ 200 x 200 x 400 m 3 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 11 ANTARES site F

12. 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 12 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009

13. AMADEUS Facts characteristics -36 sensors at 6 storeys (1 – 350m distance, 34 active) -16bit @ 250kSps sampling -~ -125dB re 1V/  Pa sensitivity -~85-90% uptime data acquisition -all data to shore -raw: 20 MByte/s (1.5 TByte/d) -filtered: 0.3 MByte/s (4 GByte/d), up to now: 4 TByte -excellent stability of all DAQ parts Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 13

14. Data Samples: Amplitude Histograms noise at different sensors gaussian profile linear correlation between sensors (factor ~ 99%) Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 14 noise and transient additional tails ~60dB S/N (SINAD), no significant crosstalk Samples (per ADC count)

15. Positioning Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 15

16. Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 16 Positioning: Method for Reconstruction use emissions from the ANTARES acoustic positioning system (not directly connected with AMADEUS) → positioning of individual sensors: use absolute time from > 3 pingers: | r reception – r emission | = c s ¢ (t reception – t emission – t offset ) t reception by threshold crossing of signal envelope t emission from positioning system → position/orientation by fitting storey geometry

17. Positioning: Example Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 17 5 days of data completely independent derivation of heading

18. 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 18 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009

19. Pinger Signals for Reconstruction of Hydrophones and AMs AMs Hydros 19 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 signal quality of AMs slightly degraded w.r.t. hydrophones (coupling, ringing of sphere,...)

20. Positioning with AMs calculate difference of individually reconstructed sensor position some issues/systematics need to be investigated 20 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 0 1 2 3 4 5

21. systematic effects due to orientation of sensors w.r.t. pingers need to be investigated for two sensors with distance at 250mm (in a sphere) better than 10° resolution reachable 21 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 Sensors 0 and 2 Heading on AM Storey

22. Positioning Option for KM3NeT AMADEUS-like acoustic sensors have the potential to combine: positioning investigation of acoustic neutrino detection techniques marine science Acoustic Modules (AMs) allow for an integration of acoustic sensors into Opto-Acoustical Modules (OAMs). First Measurements in the Lab: no significant degradation of performance of acoustic sensors by ANTARES HV base noise expected mainly from DC-DC converter 22 Kay Graf (ECAP) – VLVnT 09, Athens – October 2009

23. Source Reconstruction Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 23

24. Source Direction Reconstruction: A Dolphin beam forming or time difference algorithms used uncertainty <1° (mainly due to binning in the algorithm) 24 Intensity (au) -180 0 180 f (°) 0 0.5 1 time (ms) 90 0 -90  (°) 1 0 Amplitude (au) Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 most probable source direction

25. Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 25 Angular Distribution of Marine Sound Sources direction reconstruction for one storey all types of transient signals included origin points horizontal to north one month of data

26. Tracking of a Source reconstruction with one storey all triggered events within 500s displayed Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 26

27. Summary at UHE neutrinos are the only viable messenger beyond the local universe need a >100km 2 ∙ 2  ∙ year detector acoustic detection promising candidate complementary to optical and radio techniques (hybrid detection) AMADEUS in ANTARES: feasibility study for a future acoustic detector dedicated array in a detector environment – hybrid detection possible successfully operated since 12/2007 return of experience for future arrays (opto-acoustical?) Kay Graf (ECAP) – VLVnT 09, Athens – October 2009 27 Funded by: