Project Narrative

a. Approach, objectives, milestones, and measurements of success that will be used.

The joint Project of the US, Russia and Azerbaijan team is directed on study of the problems of ultra-high energy (UHE, >10^15 eV) and extremely high energy (EHE, >10^21 eV) neutrino astrophysics (astronomy), related with investigation of the production mechanism of cosmic rays with energies 10^15 - 10^21 eV and above in the Universe and with solution of the Greizen-Zatsepin-Kuzmin paradox (GZK). For these aims the development of the hydro-acoustical method of UHE and EHE neutrino detection and R&D of hydro-acoustical neutrino telescope – consisting of a some compact arrays placed into a sound channel - with the effective registration volume more than 1 cubic kilometer and with a rather low energy hydro-acoustic detection threshold (~10^15 eV) are suggested. Experiments based on the modern acoustic technique, previously used for Navy service, would provide unique information on the most energetic processes in the Universe due to studies of theoretically predicted fluxes of neutrinos with energy above 10^15 eV, e.g., from active galactic nuclei, as well as searching for EHE neutrinos from disintegration of the hypothetical massive particles and topological defects. In row of the theoretical models of the EHE cosmic ray production (in particular in models of the Universe with topological defects) fluxes of neutrinos with energies above 10^19 eV can greatly exceed the neutrino fluxes in models with acceleration of protons and nuclei. Therefore detection of EHE neutrinos will enable to choose the mechanism of the formation of EHE cosmic rays in the Universe: model of the "bottom up" type (acceleration of the charged particles) or "top down" type (decay of the massive particles). An idea to detect acoustical radiation of electron-hadron and electron-photon cascades, produced by UHE and EHE cosmic neutrinos in huge water masses of the World Ocean (to compensate low fluxes and weak interactions of cosmic neutrinos) was suggested in 70 th ([1]G.Askaryan et al.,1976; [2]T.Bowen, 1977; [3]J.Learned, 1979). Bipolar acoustic pulse production arises from the rapid expansion as a region traversed by a neutrino induce particle cascade, which ionizes and slightly heats the medium. An acoustic signal is emitted by a neutrino induced cascade mainly in the direction perpendicular to the cascade axis in a rather narrow solid angle. The initial spectrum peaks at a few tens of kHz. The signal spectrum at large distances shifts to a lower frequency region of a few kHz. If SADCO could detect 10-1 kHz signal produced by EHE cascades at distance of 10 to 50 km its effective detection volume could be tens to hundreds of cubic kilometers. The gain of array is a key to success. In 90th hydro-acoustic detection of UHE and EHE cosmic neutrinos in the world's oceans, employing existing hardware (arrays) was considered by participants of this project.

Authors had demonstrated that it was possible to develop a hydro-acoustic detector of 10 20-21 eV neutrinos (for example topological defect neutrinos) with an effective detection volume of tens of cubic kilometers using an existing array of 2400 hydrophones in the Pacific Ocean near the Kamchatka Peninsula. The results of simulations of acoustic signals emitted by neutrino induced cascades with energies 1020-21 eV, with realistic signal propagation in the ocean, were presented ([4]Karlik Ya. et al., 1997; [5]Dedenko L. et al., 1997)

There were further discussed the prospects of using a converted portable hydro-acoustic station of 132 hydrophones as a basic module for a deep-water acoustic neutrino telescope in the Mediterranean Sea, or elsewhere. Such a device should have a relatively low detection energy threshold of ~ 1015 eV, enabling a search for AGN and GRB neutrinos ([6]Dedenko L. et al., 2001; [7]Capone A. et al., 2001).

Recently N.Lehtinen et al., 2001 [8] and J.Vandenbroucke et al., 2004 [9] used an existing array of large-bandwidth sensors near Bagamas (a subset of 7 hydrophones located at a depth ~1600 m) to study a large sample of acoustic background events and even to present an upper limit for the flux of EHE neutrinos.

The main objectives of this proposal are to consider in detail:- simulation of neutrino cross-sections, cascades and acoustic signals produced the in water,

1

- specific features of sound channels at depths of one-a few hundred meters in the World Ocean important for neutrino detection,

propagation of acoustic signals from neutrino induces cascades in sound channels, possibilities to detect the signals (and to determine cascade (neutrino trajectory) direction!) using

a few modernized arrays of MG-10M placed in a sound channel.

The important part of proposal is the development of optimal (or close to optimal) procedures of space time signal processing from receiving array to detect useful signals and minimize the level of false alarms taking in regard that useful events are sufficiently rare.

Plans of researches on the Project include:- necessary physics calculations of neutrino-nucleon cross sections at UHE and EHE using recent

experimental and theoretical data on nucleon structure functions, electron-hadron cascades in water taking into account fluctuations and Landau-Pomeranchuk-Migdal effect, acoustic fields produced by cascades in real ocean conditions,

- study of propagation of acoustic signals from cascades in “sound channels”,- development and simulation of optimal processing algorithms and method of signal processing,- analysis of possible modern technologies for the SADCO module and the SADCO telescope

system design, reliability studies,- R&D of a replace of the MG-10M hydrophones by assemblies of 10-20 hydrophones in each one.- development of a program of the experiment in the Caspian Sea for tests of the SADCO module

“in situ” and for measurements of acoustical fields at depths ~ 100 m using one of the oil-platforms (a few of them) near Baku for logistical support.

b. Individual and combined competencies and relevant prior work of the Russian and U.S. research team.

The participants of this project have significant experience in investigations on Neutrino Physics and Astrophysics, on Hydro-acoustics in the World Ocean and in development of hydro-acoustical detection of UHE and EHE cosmic neutrinos.

University of Hawaii(old text by John –1996)

The US collaborators at the University of Hawaii (Professor J. Learned, the Co-Investigator from the U.S. group, et al.) have worked for many years on the development of the DUMAND Project, similar to, and in concert with the NESTOR Project being planned for Pylos, Greece. They engaged in many studies of acoustic arrays in the earlier days of the DUMAND Project, before specializing in the development of optical detectors. The main reason for not continuing the acoustical development in the early 1980's was that it was realized that there was no reasonable means to achieve an energy threshold low enough to have a guaranteed source of neutrinos. Such a debtor, if built, could face the prospect of seeing no signals at all. Thus the emphasis has been upon optical Cherenkov radiation detectors which can readily detect the normal neutrinos from cosmic ray interactions with the atmosphere. In the last few years the situation has evolved favorably for acoustic detection from the physics and technology standpoint. First there are predictions of substantial fluxes of UHE neutrinos originating in or near active galactic nuclei. The rates may amount to thousands of interactions of more than I PeV per year, per cubic kilometer. Secondly, acoustic technology has advanced dramatically with time, particularly in sophisticated processing techniques (facilitated by the amazing advance of computers).The US group has followed this activity over the years, and now with the optical detectors about to be launched, are ready to put effort into the development of acoustic detection. There is possibly strong synergy in the colocation of an acoustic array with an optical array. For example, we may well be able to "see" and "hear" Glashow resonance events (at 6.4 PeV), to the mutual advantage of both methodologies. Basically the strategy is to employ optical detectors for lower energies, limited by affordable volume, and to spline on acoustic detection as the means to proceed to truly huge target volumes (many cubic kilometers) at higher energies (>1016 eV).The Hawaii DUMAND group have been leaders in the field of neutrino astronomy since its conception, and have been involved in every avenue so far explored for undertaking neutrino astronomy.

Acoustic Institute, MoscowInvestigators from N.N.Andreev Institute of Acoustics (Dr. V.Svet, the Co-Investigator from the Russian group, Dr. V. Baronkin, G. Baranova) have long-term experience in different fields of ocean hydro-physics: development and efficiency analysis of space-time signal processing algorithms under various

2

models of signal and noise, including signal processing in volume and planar multi-element arrays, far-field and near-field parallel beamforming, bearing and ranging problems in inhomogeneous medium, development of space-time optimal signal processing in low signal/noise situations, processing of short low-energy impulses, development of optimal and suboptimal space-time algorithms for multi-ray propagation and inverse source tasks , modeling sound propagation in ocean medium, simulation of ocean noise and so on. Dr. V.Svet has been PI of a number classified projects on hydroacoustics. In 1995-1996 he was PI of the ONR project, (Contract № 68171-96-C-9098)

Investigators from N.N.Andreev Institute of Acoustics have stable relationships with Design Bureaus and Plants, specialized in underwater technologies. Hence there is a deep infrastructure for R&D of stationary multi-element arrays and necessary digital signal processing.

Kamchatka Hydro-physics InstituteDr. Ya. Karlik from Kamchatka Hydro-physics Institute in 1957-2003 worked at “Morfizpribor”(St. Petersburg) as Chief Designer and PI of a number of classified projects for the Soviet (Russian) Navy.Kamchatka’s array “Agam”, (fig.1) is his design.Dr. E.N. Kalenov works at KHPI since 1988 (now he is the head of department). In 1964 – 1988 he worked at “Wodtranspribor” and “Morfizpribor” (St. Petersburg) as Chief Designer of a number classified projects for the Soviet Navy.

Institute for Nuclear Research, Moscow (INR)Drs. I. Zheleznykh and A. Butkevich from the Institute for Nuclear Research, Moscow (INR) are experts in the Neutrino Physics and Astrophysics. Since students years the scope of interests of I. Zheleznykh are mainly the High-Energy Neutrino Physics and a new branch of Astronomy – the High-Energy Neutrino Astronomy, phenomenology of elementary particle interactions of very high and super high energies, research and development of alternative large-scale neutrino telescopes.He is one of the authors of ideas of underground neutrino experiments (1958-1961), searches for relic heavy magnetic monopoles (1968), scenario of extremely high energy cosmic rays (neutrinos) production due to interactions (decays) of super massive particles (1979-1981), radio wave Antarctic neutrino detection (RAMAND, 1983), radio astronomy method of hadron and neutrino detection (RAMHAND, 1988-1989). In the end of 80th – the begin of 90th he took part in a few scientific cruises in the Mediterranean Sea as an organizer of works on deep-water neutrino detection.A.Butkevich had performed a number of careful calculations of fluxes of atmospheric neutrinos, neutrino-nucleon and neutrino-electron cross-sections at UHE and EHE energies, MC study of high energy electromagnetic shower. He is a co-author of more than 60 papers. Now the scope of his interests concern to neutrino oscillation, K2K and T2K experiments, neutrino-nucleus cross-sections and MC study for neutrino detectors.Zheleznykh and Butkevich were interested in the development of the hydro-acoustic neutrino detection since 1991-1992 when the first ambient noise measurements in the acoustic frequency band 3-50 kHz at a depth of 4 km in the Ionian Sea were carried out with their participation ([10]A.Butkevich et al., 1994)Dr. A. Mironovich (INR) has significant experience in calculations of acoustic signals produced by electron-photon and electron-hadron cascades in water. The results of calculations of the UHE neutrino induced acoustic pulses in water were given in a series of articles ([11]Dedenko et al., 1995; [5]Dedenko et al., 1997; [12]Butkevich et al., 1999).

Institute of Physics, Azerbaijan National Academy of Sciences, Baku, AZERBAIJANDrs Z. Sadygov at al. are experts in semiconductor detectors, high energy physics, acoustical physics and electronics. Z. Sadygov took part in the Soviet DUMAND-type investigations in 80s and had an experience in work with deep water devices. Dr. M.A. Ramazanov is expert in field of investigation of the piezo-composite materials for their application to the combined underwater acoustic antennas. He worked on the creation and development of combined underwater antenna for study of the submarine topography and for detection of the moving targets in the aqueous medium under the orders of Navy of the Soviet Union Ministry of Defense. He participated at the tests of the underwater acoustic antennas based on piezo-composite materials for their use at the submarines. Dr. Elchin Jafarov is experienced on the field of theoretical and experiments high energy physics as well as electronics. He is a member of the CERN ATLAS Collaboration on the LHC 14 TeV proton-proton collision experiment.

Azerbaijan officials and science policymakers are interested on the participation of the Azerbaijan team within SADCO Project. The official letter from State Oil Company of Azerbaijan Republic to President of

3

the Azerbaijan National Academy of Sciences dated as 31.07.2003 indicates that under the necessity the State Oil Company of AzR is ready to arrange the required for experiment place at one of their Caspian sea platforms for implementation of the SADCO experiment and other required equipments in SOCAR (ship et al. for first expedition to selection of the point for SADCO telescope in Caspian Sea). The depth of the Caspian Sea in the proposed place is in the range of 100-200 m.

Participation of the experts on the elementary particle physics from Hawaii University, INR and the experts on the hydro-acoustics from ACIN, KHPI in SADCO collaboration, which started in the middle of 90 th , was very efficient.One of the goals of SADCO (Sea-based Acoustic Detector of Cosmic Objects) collaboration was to consider the use of already existing stationary sonar facilities, such as those placed in the Kamchatka region, as an acoustic detector of neutrinos (Karlik et al., 1997; Dedenko et al., 1997). This Kamchatka sonar installation has a large planar phased array, with 2400 hydrophones (see Fig. 1).

Figure 1The array is installed on a sea shelf and connected with on-shore equipment by cable. The sector of view is 120. The angular resolution in the horizontal plane is 0.8 in each of 150 (virtual) parallel fan-shaped beams. The vertical angular width is 7. The gain of this array is 2500 at 1400 Hz.Evaluations of the effective detection volume of the Kamchatka’s array were performed for cascade energies (1020 eV - 1021 eV), for realistic ocean noise condition and for different probabilities of false alarm (false impulse signal). It was shown that in summer time and under calm wind conditions, the Kamchatka array can have a significant detection volume (tens of cubic km) for seeking acoustic signals from 1021 eV cascades. Employing the Kamchatka’s array, it is possible to develop special software to search for electron-hadron cascades induced by EHE (topological defects) cosmic neutrinos with E >1020-21 eV and higher energies in water volumes of tens cubic kilometers and more. The frequency range of the Kamchatka array (1.0 - l.5 kHz) is not optimal because of low signal/noise input ratio and pulse noise from other sources of sound. However there is the opportunity for creation of acoustic detectors of even greater volume using an optimal bandwidth (2-20 kHz) for the signals generated by UHE and EHE neutrino induced cascades. In particular, in 2000-2001 we considered a hydro-acoustic system designated MG-10M (see Fig.2), formerly used by the USSR Navy, now withdrawn from service (Dedenko et al., 2001; Capone et al., 2001).

Figure 2The interest to this system) is due to the fact that its array has a gain about 1700 at an average frequency of 15 kHz, i.e. approximately that is necessary for optimal neutrino detection. Moreover, the receiving array is not large - a cylinder of 1.6 meters diameter and 1 meter height. The array contains 132 hydro-acoustic sensors directed in a vertical plane on a cylindrical surface. The mass of the array is about 1200 kg and it is designed for depths up to 500 meters. The frequency band is (4-25) kHz. The sensitivity is about 170 (V/Pa). This array practically matches the desired parameters of a basic module of an acoustic neutrino detector with a "low" energy detection threshold of ~1015 eV.

4

The peculiarity of MG-10M is the absence of beamforming in vertical plane. The existing array has one stationary beam in this plane. Therefore a certain modification of beamforming system in the vertical plane is required to improve the detection of neutrino signals effectively.

c. The anticipated results of the project and how they relate to the CRDF evaluation criteria.An expected duration of the project is 24 months. The results of the project will be

- development of the complex programs for calculations of neutrino-nucleon cross sections at UHE and EHE, for simulations of electron-hadron cascades in water taking into account fluctuations and Landau-Pomeranchuk-Migdal effect, for calculations of acoustic fields produced by cascades in real ocean conditions,

- study of propagation of acoustic signals from cascades in “sound channels” (preliminary calculations showed, see Fig.3, that there are principal possibilities of long range cascade detection using the “sound channel”; however, a certain optimization of the array placement is required)

Figure 3.

The example of sound field structure produced by cascade for a certain vertical sound speed profile. Feature of the cascade : length -10m, frequency-10kHz, angle (relatively vertical)- . Left: cascade depth -150 m. Right: cascade -depth 100m

- development of optimal and suboptimal processing algorithms and method of signal processing for neutrino events in sound channels,

- analysis of possible modern technologies for the SADCO module and the SADCO telescope system design, reliability studies,

- R&D on a replace of the MG-10M hydrophones by assemblies of 10-20 hydrophones in each one and construction of a modernized system,

- development of a program of the experiment in the Caspian Sea for tests of the SADCO module “in situ” and for measurements of acoustical fields at depths ~ 100 m using one of the oil-platforms (a few of them) near Baku (see Fig. 4) for logistical support,

Figure 4. Caspian sea geography of SADCO placement with basic module on the base of the MG-10M

- acoustic background will be studied and processed during 30 hours period measurements on Kamchatska hydro-acoustic station AGAM;

1. Performance Excellence. Extensive experience of the Russian, Azerbaijan and American project participants in particle physics and hydro-acoustics, their successful joint investigations (since 1997) on use of available hydro-acoustic systems for fundamental researches and the facilities available to us (MG-

5

10M antenna of INR, stable relationships with Design Bureaus and Plants to make a modernization of MG-10M, possibility to use platforms near Baku for acoustic tests etc.) confirm that the R&D of a module of the deep-water hydro-acoustic neutrino telescope can be carried out using the proposed approach. Coordination of the project and research program of participants is defined at the end of the proposal.

2.Intrinsic Merit. The results of investigation of the project may be a basis for creation of a large-scale hydro-acoustic neutrino detector (telescope) for goals of a new branch of Astronomy - UHE and EHE Neutrino Astronomy.

3. Utility. The modernized antenna MG-10M can be used as basic module of a large-scale hydro-acoustical systems for investigations (detection, localization and classification) not particle cascades only but also for solution of different hydro-acoustical tasks in a frequency band of 2-15 kHz in the Ocean).

4.Defense Conversion. Along with the many scientific and technological applications, this project also pursues Defense Conversion goals. More than 50% of FSU participants are former defense scientists. Professor, Dr. V.Svet, Dr. V.Baronkin and G.Baranova (ACIN) as well as Dr. E.Kalenov (KHPI) and Dr. M.Ramazanov (IP, Baku) were engaged before in development and design of the methods and facilities of acoustic signal processing. Their basic work in this project will be directed on the decision of system and algorithmic problems connected to detection of weak signals, optimal methods of array beamforming and optimal algorithms of signal processing in multi-ray propagation environment.Dr. Ya. Karlik (KHPI) was engaged before in development of stationary sonar for Navy applications and his experience and knowledge of methods of design and making multi-elements phased arrays is basic for performance of the given project. He will be responsible for re-design of MG-10M, implementation of new hydrophones, pre-amplifiers, multiplexors, optical interfaces and optical cable lines to provide a reading of signals from elements of the array.From the point of view of methods and means of technical design the offered acoustic neutrino detector is rather standard acoustic system for underwater monitoring, therefore participation of the experts with wide experience in the given area is a guarantee of success.5.Mutuality of Benefit. The creation of reliably working underwater systems during tens years is a very complex and expensive technical problem. And in that sense the development of the given project is rather favorable and effective from many points of view. First of all it allows to use available wide experience on design and manufacturing of underwater acoustic systems in completely new area of physics. The offer to use the available and fulfilled receiving underwater system considerably reduces terms of design and making of the acoustic detector. The cost of such detector at use of available system is many times less than the cost of development and making of new system, because about 90 % of cost of underwater monitoring system is the cost of underwater housings, array, underwater electronics, cable lines, controlling and telemetry devices.

6.Effect on the Infrastructure of Science and Engineering. The developed receiving acoustical system (hardware and software) can be used in many scientific and underwater applications. First of all this system could be applied for different tasks of underwater monitoring and investigation of various phenomena of multi-ray sound propagation in shallow water. This is a special field of ocean acoustics.There are many other industrial applications of such system: monitoring and tracking of different underwater objects, for example the solution the problems of protection of sea oil-gas platforms from the non-authorized penetration.The underwater system with appropriate optical cable lines permits to use and install different other sensors to provide wide spectrum of experiments on seismology activity, temperature variations, streams and so on.

d. Equipment to be utilized in the project. All equipment needed for development and testing of components of an improved version of the

MG-10M antenna is available at the participating institutions and at the “Vodtranspribor” company in St, Petersburg, where the update of the MG-10M should be performed. (INR has already bought one MG-10M array system). Russian group is completely equipped with the special setups to measure different parameters of hydrophones, testing the assemblies of hydrophones, providing hydraulic tests and calibration procedures. There are special stands to provide mechanical, vibration and climate tests.

6

The Russian group needs assistance in purchasing of the following equipment and materials:1. Hydrophones Anticipated cost is $10000.

Cost sharing: $20000 from the INR (other support) are included to cover the expences for preamplifiers in housing, optical interfaces, contolling devices, manpower (as well as for hydrophones too)

(Victor, $10K we ask from CRDF for Materials – Piezo-composite, $20K should be given by INR)

VICTOR!!!2. Expendable materials and computer supplies with total expected cost of $.

The U.S. group needs assistance in purchasing of the following equipment:

………. ??????///. . . . . . .(JOHN!!!)

e. How the Russian and U.S. co-investigators will coordinate project implementation.Responsibilities of the project participants and their research program are defined between the

collaborating Institutions. The main results of this project will be reported at local 3-monthly meetings. Local trips for special tests of parts of systems between Moscow, St. Petersburg and Baku will be made as required.

We also plan international trips for meetings between collaborators ( 4 trips to UH, and 2 trips to Moscow and Baku). Two out of the 6 trips are planned to conduct annual meetings between co-investigators in order to evaluate progress on the project, discuss R&D strategy and coordinate efforts between the collaborators. The other 4 trips are planned for development of simulation program and calculations.

The partners will carry out the following tasks in the project:FSU Group: FSU Contractor – N.N. Andreev Acoustics Institute (Moscow, Russia) and subcontractors – INR (Moscow, Russia), KHPI (Kamchatka, Russia) and the Institute of Physics (Baku, Azerbaijan)

Tasks to be carried out. Task performers

Duration(months/person)

1 Calculations of neutrino-nucleon cross sections at UHE and EHE using recent experimental and theoretical data on nucleon structure functions

A. Butkevich*I. Zheleznykh*

5 5

2 Simulations of electron-hadron cascades in water taking into account fluctuations and Landau-Pomeranchuk-Migdal effect

A. Butkevich*A. Mironovich*

57.5

3 Calculations of acoustic fields produced by cascades in real ocean conditions A. Mironovich*

I. Zheleznykh*7.55

4 System and technical design of underwater part, technical requirements on the updated array, TECHNICAL ASSIGNMENT on the array for Vodtranspribor

V.Svet V.Baronkin G.BaranovaYa.Karlik**E.Kalenov**

7.5 10 7.5 7.5 15

5 Simulation of sound propagation, design of methods and algorithms of signal processing, simulation of algorithms, estimation of quality of the detection in different sea conditions

V.SvetV.BaronkinG.Baranova Z.Sadygov*** M.RamazanovE.Jafarov***

7.5107.5101010

6 Design and making of the updated array, testing procedures Ya.Karlik** 7.5

*- Subcontractor from the Institute for Nuclear Research of the Russian Academy of Sciences; ** - Subcontractor from Kamchatka Hydro-Physics Institute;

7

American Group – The University of Hawaii at Manoa Tasks which will be carried out. Task

performersDuration of work(months/person)

123

References.1. Askaryan G.A., Dolgoshein B.A., 1976 DUMAND Summer Workshop, Hawaii.2. T. Bowen, Conference Papers, 15th ICRC, Plovdiv, 6, 277 (1977).3. J.G. Learned, Phys. Rev. D 19,3293 (1979).4. Karlik Ya. S., Learned J.G., Svet V.D., Zheleznykh I.M., "Hydroacoustic detection of ultra-high

energy neutrinos", Proc. 32 Rencontres de Moriond, Les Arcs, France, Jan. 18-25, 1997, Edition Frontiers, pp. 283-286.

5. Dedenko L.G., Furduev A.V., Karlik Ya. S., Mironovich A.A., Svet V.D., Zheleznykh I.M., "SADCO: Hydroacoustic Detection of Super -High Energy Cosmic Neutrinos", Proc. 25th ICRC, vol. 7, p.89, Durban, South Africa, 1997.

6. L.G.Dedenko,Ya.S.Karlik, J.G.Learned, V.D.Svet and I.M.Zheleznykh, "Prospects of Hydroacoustic Detection of Ultra-High and Extremely High Energy Cosmic Neutrinos",

AIP Conf.Proc. (2001) V.579,p.277 Melville, New York,2001.7. Capone A., Dedenko L.G., Furduev A.V, Kalenov E.N., Karaevsky S.Kh.; Karlik Ya.S., KoskeP., Learned J.G., Matveev V.A., Mironovich A.A., Smirnov E.G., Svet V.D.,

Tebyakin V.P., Zheleznykh I.M., "Hydroacoustical detection of ultra-high and extremely high energy neutrinos", Proc. ICRC 2001, p.1264, Copernicus Gesellschaft 2001.

8. N. Lehtinen, S. Adam, G. Gratta et al., astro-ph/0104033.9. J. Vandenbroucke, G. Gratta and N. Lehtinen, astro-ph/04061105.

10. A.Butkevich, S.Kh.Karaevsky, I.M.Zheleznykh et al., “Sea Acoustic Detector of Cosmic Objects - SADCO", Trends in Astro-particle Physics, Proc. 2nd Int. Conf., Teubner Texte zur Physik, Leipzig, ed. P.Bosetti, pp.128-131,1994.11. Dedenko L.G., Karaevsky S.Kh, Mironovich A.A., Zheleznykh I., "Acoustic signals produced by high-energy neutrinos in water", Proc. 24th ICRC, Rome, 1995, v.1, p.797.

12. Butkevich A.V., Dedenko L.G., Karaevsky S.Kh, Mironovich A.A.,Provorov A.L. , Zheleznykh I.M., "High energy neutrino interactions and the prospects for radiowave and acoustic detection of cosmic neutrinos (cross-sections, signals, thresholds)", Physics of Particles and Nuclei, volume 29, number 3, 266-272, 1998 American Institute of Physics.

8