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

David Waters
could not be here
due to Viviane Waters,
born August 22
Congratulations!
Report on New Technologies
(Working Group 7), Acoustics
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
P. B. Price, 1996 Astropart. Phys.
SAUND (ocean)
ACOUSTIC
Consider two regimes:
• SPATS (South Pole)
T = -51 ºC,
f >10 kHz,
a ≈ 8.6 km
or
energy
concentrated
here
• Ross Ice Shelf
T ≈ -28 ºC,
f < 1 kHz,
a ≈ 500 m
P. B. Price
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 <1 kHz have a > 500 m,
and very little energy goes into such low-frequency waves.
P. B. Price
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
Resolution studies
1) Acoustic slow 
radio/optical hits give exact
emission time for acoustic
1 R + 4 A: 2 m vertex res.
J. Vandenbroucke
2) Acoustic pancake gives
neutrino direction
<1° from acoustic pancake
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
200 acoustic modules in
Vinstr. = 1 km3
Kay Graf
rate of correlated neutrino-like
background events is not
known, only random
coincidences assumed
) measure with AMADEUS at
different length scales
AMADEUS: ANTARES Modules for
Acoustic Detection Under the Sea
ANTARES storey
2m
Kay Graf
Instrumentation
Line
with
3
acoustic storeys
(+SPY II)
(deployment
foreseen
first half 2007)
3 more acoustic
storeys in
another line
(plans to be
finalized)
South Pole Acoustic Test Setup
Stephan Hundertmark
3 strings in 3 IceCube holes, Jan 2007
SPATS tested in frozen lake, Northern Sweden
Stephan Hundertmark
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