1. David Waters could not be here due to Viviane Waters, born August 22 Congratulations!

2. Report on New Technologies (Working Group 7), Acoustics Justin Vandenbroucke for David Waters Justin Vandenbroucke for David Waters Acoustic neutrino revival, past few years: - sensor optimization and calibration - signal simulation - tests at accelerator beams - real arrays at Bahamas, UK, Mediterranean In addition to WG 7, see L. Thompson talk and G. Riccobene poster

3. SAUND (ocean) ACOUSTIC P. B. Price, 1996 Astropart. Phys.

4. energy concentrated here Consider two regimes: SPATS (South Pole) T = -51 ºC, f >10 kHz, a ≈ 8.6 km or Ross Ice Shelf T ≈ -28 ºC, f < 1 kHz, a ≈ 500 m P. B. Price

5. Acoustic array on Ross Ice Shelf for GZK neutrinos? Advantages: Flatness: acoustic waves can propagate by hopping along firn-air interface. Cheap: deploy at the surface; no drilling required Close to McMurdo; more accessible than South Pole Disadvantages: At T ≥ -28ºC, only waves with f 500 m, and very little energy goes into such low-frequency waves. P. B. Price

6. Coincident effective volumes + event rates for IceCube (I), an optical extension (O), and combinations with surrounding A + R arrays (GZK events/yr) astro-ph/0512604

7. Resolution studies 1) Acoustic slow  radio/optical hits give exact emission time for acoustic 1 R + 4 A: 2 m vertex res. 2) Acoustic pancake gives neutrino direction <1° from acoustic pancake J. Vandenbroucke

8. 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 Kay Graf

9. 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: ANTARES Modules for Acoustic Detection Under the Sea ANTARES storey 2 m2 m Kay Graf

10. South Pole Acoustic Test Setup 3 strings in 3 IceCube holes, Jan 2007 Stephan Hundertmark

11. SPATS tested in frozen lake, Northern Sweden Stephan Hundertmark

12. Discussion: Hybrid approach Is it desirable? No: 1) Length and energy scales different, don’t hamstring one just for overlap Yes:1) Seeking rare events, want redundancy 2) Overcome systematics, improve resolution Much optimization to do, e.g. mazimize total or coincident event rate? Suggestion: 1)Build small independent arrays to understand each technique (possibly in same location), be ready to optimize and expand 2)Deciding and optimizing will require fully understanding each technique and discovering some events