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SADCO
Sea Acoustic Detector of Cosmic Objects:
status of a pilot experiment in the Caspian Sea
Igor Zheleznykh, INR, Moscow
for SADCO collaboration
John Learned reporting a Stanford, 14 Sept 2003
I.
Introduction:
Short history of HENA.
Need in cubic km-size (KM3) detectors for HENA
II. Hydro-acoustical method of UHE(EHE) cosmic neutrino detection:
30 years of its development for UHENA and EHENA
III. Russian Navy stationary hydro-acoustical antennae for HENA:
Kamchatka array AGAM of 2400 hydrophones
IV. Portable submarine antenna of 132 hydrophones as a basic module
of a deep-water acoustic neutrino telescope: status and prospects
I.
Introduction.
First estimations and comparison of atmospheric and
astrophysical HE (E ~ 1-1000 GeV) neutrino fluxes had been
carried out in 1958-1960 (Markov and Zh.) and Greisen (1960).
Fluxes of HE atmospheric neutrinos are higher than
astrophysical ones produced by standard Cosmic Rays.
But: productive point astrophysical neutrino sources might exist!
So underground (underwater) HE neutrino experiments were
suggested (M.A. Markov et al) for investigations of 2 problems:
1.
2.
-- High-Energy Neutrino Physics:
Investigation of neutrino interactions with matter using available
atmospheric neutrinos with energies 1-1000 GeV
(energy growth of neutrino cross-sections, intermediate bosons
etc);
-- High Energy Neutrino Astrophysics (HENA):
Search for fluxes of HE cosmic neutrinos from astrophysical
objects.
HE neutrino (gammas) sources discussed in 1958 – 1961**
– Galaxy center, SN remnants (Crab Nebula);
HE gammas (as well as HE neutrinos) are produced in the strong
interactions: HEGA was suggested as complimentary to HENA
HE cosmic neutrinos (as well as gammas) – indicator of the most
energetic (strong) processes in hot places of the Universe; so
detection of cosmic neutrinos might be a new branch of Astronomy
which is complimentary to Electromagnetic Astronomies (optical,
radio, X-ray…)
** M.A.Markov, Proc. Rochester Conf. (1960) p. 579;
I.M.Zheleznykh, Diploma paper, Depart. of Phys., Moscow Univ., 1958
I.M.Zheleznykh and M.A.Markov. In: High-energy Neutrino Physics D-577,
Dubna (1960);
M.A.Markov and I.M.Zheleznykh, Nucl. Phys. 27 (1961) 385
In 70th it was understood that kiloton HE neutrino
telescopes which were under construction (Baksan et al)
would not be able to register HE cosmic neutrinos.
1975: Fred Reines, John Learned, Arthur Roberts, Vic
Stenger et al – idea of Gigaton underwater HE Neutrino
Telescope (DUMAND).
1976 - 1979: Gurgen Askaryan et al, Ted Bowen, John
Learned – idea of hydro-acoustic UHE neutrino
detection.
So KM3 – cubic km - scale detector for HE and UHE
Neutrino Astrophysics (Astronomy) – is needed !
(M.Shapiro, Silverberg, Beresinsky et al)
New arguments to support construction of large-scale (DUMANDtype) NT for investigations of super GZK- particles were discussed in the
end of 70th – begin of 80th by M.A.Markov and his group:
--the possibility of the existence of particles with energies 1020-1028 eV
originating in the decays of the Mini-Black Holes*;
--maximons (particles with Plank mass) and EHE particles**;
--neutrinos with energies above 1020 eV as a result interactions (decays)
of the hypothetical super heavy particles***
* M.Markov and I.Zheleznykh, Proc. DUMAND-1979, p.177
** V.Maltsev and M.Markov (1980), V.Frolov and M.Markov, (1979)
***L.Dedenko, M.Markov and I.Zheleznykh, Proc. Neutrino-81, Maui, p.92 (in this
paper the suggestion was also made to search for the electron-photon and hadron
cascades produced by super-GZK neutrinos in the atmosphere by radio method)
Top–down models and possible EHE neutrino sources
discussed last years:
- decays of topological defects (see G.Sigl, 2002)
- decays of long-living X-particles with masses 1022 - 1026 eV
Kuzmin and Rubakov, 1997;
Beresinsky et al., 1997
Such objects are objects of much interest for HENA
(and hydro-acoustical UHE and EHE neutrino detection!)
II. HYDRO-ACOUSTICAL DETECTION
of neutrino-induced cascades
SADCO in the
MEDITERRANIEN.
Acoustical background
measurements, 1991
III. New Era of SADCO since 1997:
to use Russian Navy stationary antennae
for
IV. PORTABLE SUBMARINE ANTENNA MG-10M
as a basic module of the deep-water Neutrino Telescope
SADCO collaboration have now:
- one MG-10M antenna of 132 hydrophones,
- Agreement with a plant in St.Petersburg to make
necessary tests of this antenna,
- Agreement with Azerbaijan Ac. Sci.,
- programs for simulations acoustic signals from
cascades in water, transportation of the signals in the
Real Ocean etc.
Table. Parameters of cascades in water with
the LPM-effect
Energy of electron
Diameter of cascade
D, cm
E0, eV
Length of cascade in
water
L,m
Mean energy deposition
dE/dx, eV/cm
1018
12
66
1.51пѓ—1014
1019
12
176
5.68пѓ—1014
1020
12
468
21.36пѓ—1014
1021
12
1320
75.57пѓ—1014
Distribution of energy deposition by1018 electron in water
with the LPM-effect
d E /d V , M eV /m 3
E =10
5 0 x1 0 1 2
0
18
eV
4 0 x1 0 1 2
3 0 x1 0 1 2
2 0 x1 0 1 2
1 0 x1 0 1 2
5
4
0
60
3
50
40
Z
30
,m
2
20
10
1
cm
,
r
Comparison of distribution of energy depositions by 1019
and 1018 electrons in water (with the LPM-effect)
3
dE /d V , M eV /m
E 0= 1 0 19 e V
1 5 0 x 1 0 12
1 0 0 x 1 0 12
5 0 x 1 0 12
5
4
3
0
160
2
140
120
100
Z
80
,m
60
1
40
20
r
m
c
,
Comparison of distribution of energy depositions by 1020
and 1018 electrons in water (with the LPM-effect)
dE /dV , M eV /m 3
1 x1 0 1 5
E 0= 1 0
20
eV
8 0 0 x1 0 1 2
6 0 0 x1 0 1 2
4 0 0 x1 0 1 2
2 0 0 x1 0 1 2
0 1
2
3
r ,
cm
4
5
0
100
300
200
Z
,m
400
Distribution of frequencies of acoustic signals at 0.4; 1; 3;
10 km by the electron cascade of 1021 eV in water with the
LPM-effect
8 .0 x1 0
5
E0 = 10
пЃ¤ P / пЃ¤ f ( пЃ­ P a/M H z)
6 .0 x1 0
4 .0 x1 0
2 .0 x1 0
21
0 .4 k m
1 .0 k m
3 .0 k m
1 0 .0 k m
eV
5
5
5
0 .0
10
-3
10
-2
f (M H z )
10
-1
Distribution of energy deposition by 1021 eV electron in
water with the LPM-effect
d E /d V , M eV /m 3
2 .5 x1 0 1 5
E 0= 1 0 21 e V
2 .0 x1 0 1 5
1 .5 x1 0 1 5
1 .0 x1 0 1 5
5 0 0 .0 x1 0 1 2
0 .0
r
2
,c
3
4
m
5
0
200
400
600
Z
800
,m
1000
1200
Acoustic pulses at distances of 0.4; 1; 3: 10 km by the
electron cascade of 1019 eV in water with the LPM-effect
0 .4 k m
1 .0 k m
3 .0 k m
1 0 .0 k m
2500
2000
пЃ„ P (пЃ­ P a )
1500
E0 = 10
1000
19
eV
500
0
-5 0 0
-4 0
-2 0
0
20
40
60
80
100 120 140 160 180 200
tim e ( пЃ­ s )
Dependence of the peak value of acoustic signal on distances for
various energies of cascades 1018–1021 eV in water with the LPM-effect
10
10
10
1000
10
20
19
18
eV
eV
eV
eV
пЃ„P
m ax
(пЃ­ P a )
10000
21
100
10
100
1000
R 0 (m )
10000
Dependence of the peak value of acoustic signal on
shifting of the observation point along the cascade length
for the 1018 eV electron cascade at 400 m
1000
E0 = 10
800
18
eV
600
400
пЃ„P
m ax
( пЃ­ P a)
R 0 = 400 m
200
0
0
5
10
15
R 0 (m )
20
25
30
Could Russian Navy help to HENA in searches for
topological defects in our Universe? Yes, they could.
USA Navy?
French Navy?
It would be great
if to cooperate!
We should ask G.Gratta.
We should ask L.Moscoso.
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