1. Kay Graf Physics Institute University of Erlangen TeV Particle Astrophysics II Madison, WI, USA August 28 – 31, 2006 Towards Acoustic Detection of UHE Neutrinos in the Mediterranean Sea – The AMADEUS Project in ANTARES

2. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 2 Acoustic Detection of UHE Neutrinos energy deposition in (hadronic) cascade ) disc-shaped bipolar pressure pulse N.G. Lehtinen et al., Astropart. Phys., 17 (2002), p. 279

3. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 3 AMADEUS: Project and Objectives AMADEUS: ANTARES Modules for Acoustic Detection Under the Sea equip several storeys of the ANTARES detector with acoustic sensors evaluate the feasibility of an acoustic neutrino detector using a dedicated array of sensors investigate the acoustic background: noise and signals at different length scales comparable to a future detector test hardware/software and signal processing in a realistic surrounding located in a deep-sea environment ) within the framework of the ANTARES experiment

4. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 4 Simulations of an Acoustic Detector T. Karg, PhD Thesis, astro-ph/0608312 (2006) effective volume and energy threshold strongly dependent on detection threshold of sensors ) design and test efficient signal processing algorithms rate of correlated neutrino-like background events is not known, only random coincidences assumed ) measure with AMADEUS at different length scales 200 acoustic modules in V instr. = 1 km 3

5. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 5 Previous Studies at ANTARES site autonomous system with acoustic sensors inside Ti-cylinder on ANTARES test line (2005) successful data taking for 20 h but limited capability (electronics noise, vessel) ) test data processing algorithms anchor of Line0

6. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 6 Previous Studies at ANTARES site SPY Hydrophone (CPPM Marseille) on MILOM (since 2005) electronics and software fully working, but not sensitive to background noise (40 dB loss) ) SPY II on next Instrumentation Line storey of MILOM P (Pa) f (kHz) time (ms)

7. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 7 Instrumentation Line with 3 acoustic storeys (+SPY II) (deployment foreseen first half 2007) 3 more acoustic storeys in another line ( plans to be finalized) AMADEUS at ANTARES ANTARES storey 2 m2 m

8. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 8 From Optical to Acoustic Storey or Concept: no interference with ANTARES optics as little design changes as possible Main changes: sensors: optical modules to hydrophones or acoustic modules off-shore digitization boards: ARS board to acoustic ADC board new on-shore PC farm

9. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 9 Piezoceramic Sensors acoustic module: 2 sensors (piezo with preamplifier) in one glass sphere hydrophones: 2 separate sensors (commercial or custom) complementary: use both! +water tightness guaranteed +no design changes needed +no pressure on components -alters acoustic signal + position can be optimized +characteristics tuneable +better directional sensitivity -assure water tightness

10. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 10 Sensor Characteristics – Prototype self-noise at SS0 level (lowest agitation) (SS0: noise PSD ¸ 20dB re  Pa/Hz 1/2 at 30kHz) commercial hydrophones prototype (18 sensors in production) sensitivity: measurement and fit from simple piezo model final version: + 10 – 15 dB self-noise: after post-amplification and filtering with ADC board in air, noisy surrounding

11. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 11 Prototype Acoustic ADC Board analogue part: filtering (band pass) amplification (1 – 562) low noise (O[  V/Hz 1/2 ]) digital part: flexible design (FPGA) continuous sampling ( · 500 kS/sec, 16-bit) formatting of data communication to shore transmission: 1.25 MS/sec per storey 3 boards per storey, 2 sensors each low power ( ¼ 1 W)

12. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 12 Performance 3 (+3) storeys with 18 (36) sensors at 3 length scales ( ) dynamic range ¼ 3 mPa – 10 Pa (RMS) read-out sensors continuously and synchronously at ¸ 200 kS/sec data rate 10 (20) MB/sec flexible design (sensors, gain, filter) ? 1m1m 10 m 100 m

13. TeV Particle Astrophysics II – Madison Kay GrafUniversity of Erlangen August 28 – 31, 2006 13 Summary and Outlook 3 ANTARES storeys will be equipped with acoustic sensors (option for 3 more) dedicated setup to investigate the feasibility of an acoustic -detector currently in prototype and testing phase of components Installation of AMADEUS in 2007 if acoustic detection proves feasible ) use KM3NeT-infrastructure for acoustics? (not included in EU design study!)