A Device for Detection of Acoustic Signals from Super High Energy Neutrinos Presenter: Presenter: G.L.Pan'kov Applied Physics Institute of Irkutsk State University Irkutsk, Russia 2005

2 Baikal Collaboration Institute of Nuclear Research, Russian Academy of Sciences (Moscow, Russia) : V.M.Aynutdinov, V.A.Balkanov, L.B.Bezrukov,D.A.Borschev, I.A.Danilchenko, Ya.I. Davidov, Zh.-A.M.Djilkibaev, G.V.Domogatsky, O.N.Gaponenko, A.M.Klabukov, S.I.Klimushin, A.P.Koshechkin, B.K.Lubsandorzhiev, S.P.Mikheyev, A.I.Panfilov, D.P.Petuhov, P.G.Pokhil, V.A,Poleschuk, B.A. Shaibonov, E.A.Vyatchin, V.A.Zhukov Irkutsk State University (Irkutsk, Russia): N.M.Budnev, A.G.Chensky, O.A.Gress, T.I.Gress,O.G.Grishin, A.N.Dyachok, R.R.Mirgazov, Yu.V.Parfenov, A.A.Pavlov, A.A.Kochanov, G.L.Pan'kov, L.V.Pan'kov, V.Yu.Rubtzov, Yu.A.Semenei,B.A.Tarashansky Moscow State University (Moscow, Russia): L.A.Kuzmichev, M. Mehanov, E.A.Osipova, E.G.Popova, V.V.Prosin, A. Shirokov, I.V.Yashin Nizhni Novgorod State Technical University (Nizhni Novgorod, Russia): V.F.Kulepov, M.B. Milenin, S.V. Fialkovski St.Petersburg State Marine Technical University (St.Petersburg, Russia): M.I.Rozanov Kurchatov Institute (Moscow, Russia): A.I.Klimov Joint Institute for Nuclear Research (Dubna, Russia): I.A.Belolaptikov, K.V.Konischev,E.N.Pliskovsky, R.V.Vasiljev DESY -Zheuthen (Zeuthen, Germany): T.Mikolajski,Ch.Spiering, R.Wischnewski

3  The main requirements 3 dimensional net of 4 hydrophones as minimum 3 dimensional net of 4 hydrophones as minimum Sampling frequency of ADC not less then 100 kHz Sampling frequency of ADC not less then 100 kHz  The additional requirements The preliminary analysis under water to reject background The preliminary analysis under water to reject background Operation mode with external Trigger : from Baikal Neutrino Telescope NT200+ Operation mode with external Trigger : from Baikal Neutrino Telescope NT200+

4 A Device for Detection of Acoustic Signals

5 Minicomputer ADC card Modem Hph3 Hph1 Hph2 Hph4 Power supply Signal The schema of the device BOX Power

6 Shore Connection: via NT200+ Acoustic DAQ AVIV Modem Flex DSL Modem AVIV Modem Electric shore cable Master signal From NT Mbit/s 512 kbit/s Acoustic Device NT200+ Central DAQ

7 Antenna of the Device

8 Electronics

9 The devices tasks  Continues monitoring of statistical acoustic noise parameters. (Mean value, dispersion and so on).  The search of signals of definite waveform and length.  The collection of continues data after receiving of master signal from NT (The most important regime).

10 Autonomous operating mode Acoustic Time Series From Hydrophones Extraction of Statistical Information Signal Detection And Classification Store Signals in a Dynamic Arrays Check signals for “Time Window” condition Direction and Distance Estimation Final Data Representation Send Data to the Shore Station

11 Statistical characteristics of a signal Mean Value (Signal Level): Noise level estimation: Processing of an array with elements : 1)2) 3) Internal Dispersion (for control of electronics) External Dispersion Total Dispersion

12 We accept only signals which satisfy to the following condition: - time of propagation of a signal from one hydrophone to another - distance between two hydrophones - sound velocity at the depth where antenna placed - error in estimation of “Time window” condition

13 Accepted and Rejected signals

14 Parameters of waveform for classification procedure  The number of quasiperiods  Maximum and minimum amplitude of each extremum of signal  The total length of signal  The length of each component of signal

15 Signal Detection and Classification Procedure Statistical Module Signal Detection Module Dynamic Array

16 Direction and Distance Estimation  For signals from the distances >50m acoustic front is flat.  We measure time coordinates of each signal:  The procedure of obtaining consists in minimization of a functional: where where Start point of a signal in time series Start point of a signal in time series Position of center of a pyramid in the chosen system of coordinates Position of center of a pyramid in the chosen system of coordinates Positions of hydrophones Positions of hydrophones The moment of passage sound front through a point The moment of passage sound front through a point Time estimation mistake Time estimation mistake

The bipolar impulse

Unknown impulse

19 Electric Pickup =200us

20 An example of bipolar impulse = 60us

21 Mean STD in all channels : :30 One measurement per minute

22 Mean STD in all channels : :27 One measurement per minute

23 Zenith angel distortion degrees Absorption hat Hydrophone

24 Acoustic device

25 The Summary 1. A device for registration and preliminary analysis of acoustic signals has been constructed and tested in-situ in April, In 2006, we intend to deploy the device for one year operation together with the Baikal Neutrino Telescope. Possible location: ~100m below water surface.