Acoustics

1
Acoustics
(Activity of ITEP group)
V.I. Albul 1), V.B. Bychkov 1), V.S. Demidov 2),
E.V. Demidova 2), K.E. Gusev 2), N.K.Krasnov
1), A.F. Kurchanov 1), V.E. Lukyashin 2), V.I.
Lyashuk 2), E.G. Novikov 2), A.A. Rostovtsev 2),
A.Yu. Sokolov 2), S.S. Vasilev 1), D.N.
Zaborov2) 1) Mendeleev All-Russia Research
Institute for physics-technical and
radio-technical measurements, Mendeleevo, Moscow
region 2) Scientific Center of Russian Federation
Institute of Theoretical and Experimental Physics
( ITEP ), Moscow
1. Proton beam measurements 2. Acoustic signal
simulation 3. Sensitive hydrophone manufactiring
4. Experiment at the Lake Baikal
2
Proton beam 200 MeV / 70 ns / 108 1012
protons / Diam 1-5 cm

• Measurement of the signal
• shape and propagation inside the
• water volume.

II. Measurement of a tempera- ture dependence
of the acoustic signal formation.
P
P
3
A structure of the acoustic field as measured by
a movable hydrophone synchronized with the
proton beam.
Sound sources
A acoustic trace from the absorbed beam B-D
acoustic signal from the Bregg peak A-C
acoustic signal from beam entry point
These 3 sound sources define a structure of the
recorded signals.
4
The temperature was varied between about 1o C
and 8o C
At T4oC the acoustic signals change polarity and
get broader
Amplitude
4oC
5
Simulation of an acoustic signal
calculations
energy deposition in water E 3.2 E17ev,
distance 0.32m (compared to the model of
G.A.Askarian )
The model underestimates the ITEP proton beam
measurements by factor of 2
6
Deep water hydrophones ( ITEP, Moscow), used for
searching of signals from extensive atmospheric
showers and acoustic investigations in the
experiment BAIKAL during expeditions of 2001 -
2003 years
7
Scheme of the acoustic experiment
lake Baikal
March, 23 April, 4 2003
Scintillator detectors (EAS trigger)
50 m
50 m
30 m
H1 (4 m)
B4 (4 m)
B3 (4 m)
G7 (9 m)
G8 (9 m)
B6 (4 m)
H2 (9 m)
H3 (14 m)
H4 (19 m)
hydrophones (name and depth shown)
8
Hydroacoustic antenne of ITEP (Moscow), used for
searching of signals from extensive atmospheric
showers in the experiment BAIKAL
9
An example of detected sound (hydrophones
H1-H4,G7,G8)
Arbitrary units
10
An example of detected sound (hydrophones
B4,B6,B3)
Arbitrary units
This example presents a background signal (not
a signal from EAS)
11
Distribution of the delays in the triangle of
hydrophones located on a horizontal plane
(H2-G7-G8)
The ellipse corresponds to real physical sounds
located near horizontal plane
f
Sounds coming from or through the center of the
experimental setup
12
Angular distribution of sources seen from H2,
calculated from arrival times of signals at
(H2-G7-G8)
sin ?

• 3 clusters
• ? 90º surface noise
• ? 0º ???
• ? -10º ???
• noise channeling below ice due to temperature
  gradient ?

?
t8-t2 ((d8-d2)/v)cos ?cos (? s - ?82) t7-t2
((d7-d2)/v)cos ?cos (? s - ?72)
13
Acoustic noise from Baikal water