Excitation of elastic oscillations in solids by a pulsed proton beam
At present, the beams of charged particles are used not only in fundamental researches but they have found a wide application in solving the plasma electronics problems, modification of material surfaces properties and in a number of other applications.
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| Дата: | 1999 |
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| Автори: | , , , , , , , , |
| Формат: | Стаття |
| Мова: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Назва видання: | Вопросы атомной науки и техники |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/81363 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Excitation of elastic oscillations in solids by a pulsed proton beam / V. Belan, V. Butenko, B. Ivanov, Yu. Kolyada, Ya. Fainberg, V. Fedun, I. Onishchenko, V. Prishchepov, A. Yegorov // Вопросы атомной науки и техники. — 1999. — № 3. — С. 79-81. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-813632015-05-15T03:02:06Z Excitation of elastic oscillations in solids by a pulsed proton beam Belan, V. Butenko, V. Ivanov, B. Kolyada, Yu. Fainberg, Ya. Fedun, V. Onishchenko, I. Prishchepov, V. Yegorov, A. At present, the beams of charged particles are used not only in fundamental researches but they have found a wide application in solving the plasma electronics problems, modification of material surfaces properties and in a number of other applications. 1999 Article Excitation of elastic oscillations in solids by a pulsed proton beam / V. Belan, V. Butenko, B. Ivanov, Yu. Kolyada, Ya. Fainberg, V. Fedun, I. Onishchenko, V. Prishchepov, A. Yegorov // Вопросы атомной науки и техники. — 1999. — № 3. — С. 79-81. — Бібліогр.: 4 назв. — англ. 1562-6016 http://dspace.nbuv.gov.ua/handle/123456789/81363 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| language |
English |
| description |
At present, the beams of charged particles are used not only in fundamental researches but they have found a wide application in solving the plasma electronics problems, modification of material surfaces properties and in a number of other applications. |
| format |
Article |
| author |
Belan, V. Butenko, V. Ivanov, B. Kolyada, Yu. Fainberg, Ya. Fedun, V. Onishchenko, I. Prishchepov, V. Yegorov, A. |
| spellingShingle |
Belan, V. Butenko, V. Ivanov, B. Kolyada, Yu. Fainberg, Ya. Fedun, V. Onishchenko, I. Prishchepov, V. Yegorov, A. Excitation of elastic oscillations in solids by a pulsed proton beam Вопросы атомной науки и техники |
| author_facet |
Belan, V. Butenko, V. Ivanov, B. Kolyada, Yu. Fainberg, Ya. Fedun, V. Onishchenko, I. Prishchepov, V. Yegorov, A. |
| author_sort |
Belan, V. |
| title |
Excitation of elastic oscillations in solids by a pulsed proton beam |
| title_short |
Excitation of elastic oscillations in solids by a pulsed proton beam |
| title_full |
Excitation of elastic oscillations in solids by a pulsed proton beam |
| title_fullStr |
Excitation of elastic oscillations in solids by a pulsed proton beam |
| title_full_unstemmed |
Excitation of elastic oscillations in solids by a pulsed proton beam |
| title_sort |
excitation of elastic oscillations in solids by a pulsed proton beam |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
1999 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/81363 |
| citation_txt |
Excitation of elastic oscillations in solids by a pulsed proton beam / V. Belan, V. Butenko, B. Ivanov, Yu. Kolyada, Ya. Fainberg, V. Fedun, I. Onishchenko, V. Prishchepov, A. Yegorov // Вопросы атомной науки и техники. — 1999. — № 3. — С. 79-81. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T06:05:58Z |
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2025-07-06T06:05:58Z |
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| fulltext |
EXCITATION OF ELASTIC OSCILLATIONS IN SOLIDS BY A PULSED
PROTON BEAM
V.Belan, V.Butenko, B.Ivanov, Yu.Kolyada*,Ya.Fainberg, V.Fedun*, I.Onishchenko,
V.Prishchepov, A.Yegorov
NSC KIPT, Kharkov, Ukraine, *Priazovski State Technical University
INTRDUCTION
At present, the beams of charged particles are
used not only in fundamental researches but they have
found a wide application in solving the plasma
electronics problems [1], modification of material
surfaces properties [2] and in a number of other
applications.
Beams of the charged particles, interacting with
solids, excite elastic oscillations [3,4]. The energy flows
of pulsed intense beams can achieve 1012-1014 W, that
considerably exceeds the power of known controlled
energy sources. Therefore, the use of intense beams for
generation of elastic oscillations is of increasing
interest.
It is possible to mark three basic mechanisms
of elastic pulse excitation by intense beams of charged
particles, namely: shock, thermoelastic, and ablation
ones. The shock mechanism - generation of oscillations
by transfer of beam momentum to the target - is the
basic mechanism in the range of small energies, when
the effective reflection of particles from target surface
prevails. Thus the double momentum of beam pulse is
transferred to the target. With increasing of beam
energy, the particles penetrate into target substance,
transferring to the target both momentum and energy.
Irradiated volume is heated up and deformed,
exciting an elastic wave. If the absorbed energy results
in intensive evaporation of a target, the ablation
mechanism is included forming a pulse of pressure due
to the ablation process. The pulsed pressure to 108 Pa in
solids can be achieved with the thermoelastic
mechanism and 109- 1012 Pa with ablation development
[4], while modern piezoelectric and magnetostriction
converters used in ultrasonic engineering have
allowable pressure only to 107 Pa.
In this connection of increasing interest is the use
of charged particles beams for generation of ultrasonic
oscillations, which are greatly required in physics and
engineering. At present the ultrasound has a wide
application for the intensification of technological
processes, defectoscopy, modification of material
properties, signals processing and propagation.
The experimental works performed early [3, 4]
with electronic and ion beams have a demonstrating
character, the fact of excitation of elastic pulses in the
condensed substance was established. Besides, the
excitation of pressure pulses by ion beams is more
effective, comparatively to electronic ones, since ion
beams have considerably larger energy linear losses.
EXPERIMENTAL SET UP
In the given work the experimental results on
research of excitation of ultrasonic oscillations with a
proton beam in a specific system represented by the
acoustic waveguide are represented. The transition to
heavy particles, in comparison with electrons, has
allowed to find out the effect of ultrasound excitation at
the comparatively low beam currents of about 5-20 mА.
The energy of the beam remained constant - 5 МeV, the
duration of beam pulse varied from 5 µsec up to 20 µ
sec, cross section of the beam was 1 сm2. The scheme of
the experimental setup is represented in Fig 1. The
proton beam falls down the edge face of the acoustic
waveguide (2). Excited oscillations were registered by
piezosensors (31-34) placed along waveguide length. The
signals were fed to the electronic oscillograph. As an
acoustic waveguide the prism manufactured from an
acrylic plastic with the sizes 1.5·1.5·60 cm3 was used.
The choice of the given material is caused by the fact
that its wave resistance ρvs is close to the wave
resistance of liquids, with which the irradiator should be
matched (ρ is density, vs is sound velocity).
Fig. 1 Scheme of experimental setup
EXPERIMENTAL RESULTS
In the work the spatial-amplitude characteristics
of excited oscillations and spatial distribution of the
acoustic wave amplitude in the waveguide are
investigated, the modes of excited waves are identified.
The characteristic oscillogram of oscillations
(а), registered by piezosensors 31-34 is represented in
Fig.2 This oscillogram is obtained by means of the
sensor 31, placed at the distance 15 cm from the
interaction region of the beam with the target
(waveguide edge). The sensor sensitivity is 1.5 µV/Pа,
maximum amplitude corresponds to the value of
pressure ~ 103 Pa. The bottom oscillogram (b) is the
calibration signal of frequency 100 kHz.
Fig. 2 Characteristic oscillograms of elastic oscillations
(a) and calibrating signal (b).
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. №3.
Серия: Ядерно-физические исследования. (34), с. 79-81.
79
From the analysis of oscillograms it follows, that
the excited oscillations represent harmonic damping
sound oscillations at characteristic frequency ~ (0.8-1)
.105 Hz. Parameters of ion beam during measurements
are the followings: current 20 mА, energy 5 МeV, pulse
duration 10 µsec.
Fig.3 Dependencies of oscillations amplitude upon the
value of beam current (a), and upon pulse duration (b)
The dependencies of the maximum amplitude
of oscillations upon beam current and pulse duration
were investigated. In the diagrams of Fig.3 the
dependencies of oscillations amplitude upon the value
of beam current (a), at pulse duration of 10 µsec., and
upon pulse duration (b), at beam current of 10mА are
represented. The values of amplitude are given by
arbitrary units. Each point in the diagrams is evaluated
by averaging the experimental measurements for 5
pulses. From the represented results it follows, that the
maximum amplitude grows directly proportionally to
increase of beam current and pulse duration. It is
necessary to note especially, that the frequency of
excited oscillations and character of damping in all
cases remains constant.
In the diagram of Fig.4 the change of the
maximum amplitude of oscillations along the
waveguide is shown. The measurement of distance was
made from place of beam interaction with target -
waveguide edge. As it follows from the represented
diagram, the amplitude decreases by the exponential
law.
Fig.4 Change of the maximum amplitude of oscillations
along the waveguide
THEORY
For the determination of excited frequencies
range and oscillations identification it is necessary to
consider the character of acting force and properties of
the system - acoustic waveguide. In this case the
external acting force is displayed as impact working
during some time (duration of beam pulse). The most
probable mechanism of energy transfer to the acoustic
system resulting the oscillations excitation, is the
thermoelastic one.. Really, at the fixed beam energy 5
МeV, current 5-20 mА, area of cross section 1см2, the
density of energy flow is equal q= (2.5-10).108 W/m2,
that is lower by some orders of magnitude than the
critical q*, at which ablation arises [4].
q T* τ λ δ
α
= if ( )δ α τ> >
1
2 (1)
where T=0.1L/R, α and λ are the temperature and
thermoelastic factors, respectively, δ is the length
ionization proton losses in target; in this case it makes
the value ~ 10 -2сm; L is mole evaporation heat, R is
universal gas constant,τ is duration of beam pulse.
The acoustic properties of the acoustic
waveguide are determined by its geometrical sizes and
elastic properties of material. In this case there may be
the propagation of harmonic eigenwaves extending
along the waveguide without change of the wave form.
By the structure of sound field each eigen wave
represents a single wave propagating along the
waveguide and standing in a transversal direction. In
solid rods the eigenwaves are characterized by critical
frequencies and essential dispersion. The acoustic field
of the wave propogating along the axis Z, is determined
by the relation:
P A n
d
x m
l
y
i k n
d
m
l
z i t
nm nm= ×
× ± −
−
−
cos cos
exp
π π
π π ω2
2 2 (2)
where Anm is the wave amplitude, x, y are the
transversal directions of waveguide, d and l are the
appropriate cross sizes, n and m are the numbers of
waves, which take meanings 0,1,2,3 …, k is wave
number. The dispersion of phase and group velocities is
given by expressions:
80
v
v
n
kd
m
kl
ph
s=
−
−
1
2 2π π (3),
v v n
kd
m
klg s= −
−
1
2 2π π (4).
If ( ) ( )κ π π> +n d m l2 2 , then wave propagation
takes place; if ( ) ( )k n d m l< +π π2 2 , then wave
propagation is impossible. The critical frequency, being
lower for the wave be not propagating, is determined
from the relation:
ω π π
nm cr sv n
d
m
l,
2 2
2 2
=
+
(5).
If ω<ω mn,cr the phase velocity goes to infinity, and
group velocity to zero to (3) and (4), respectively. The
wave nature turns into oscillatory one with the
amplitude decreasing along the waveguide by the
exponential law. The fact of excitation of namely this
wave is proved experimentally (oscillogram of Fig. 2,
diagram of Fig. 4). Under the conditions of experiments
the minimum meaning of critical frequency is equal:
f11,cr ≈ 1.2 105 Hz, (ω=2πf). The registered frequency has
value (0.8-1) 105 Hz and does not depend on beam
current and pulse duration. The excitation of sound
wave at the given frequency is caused by oscillatory
properties of the system. The influence of pulsed
nonsinusoidal force on it results in occurrence of
damping oscillations at eigenfrequency. Proceeding
from the Hooke law, it is possible to show that the
characteristic frequency f of «sounding» will be
determined only by elastic properties and geometrical
sizes of the oscillatory system.
ρ λ
Ef = (6)
Here Ε is the Young module, λ is the characteristic
wavelength determined by the waveguide cross sizes.
For the given material Ε ~ 7.5*109 Pa, ρ-= 1.2 103
kg/m3, waveguide cross sizes d = l = 1.5 cm determine
the length of the first order wave λ=3 cm. At these
parameters of the oscillatory system the calculated
frequency coincides with measured one.
It should be noted, that the critical frequency of a
given acoustic waveguide (1.2∗105 Hz) differs from
registered one (under critical, equal to 0.8-1∗105 Hz), by
the value of measurements error. However, the fact of
exponential decrease of amplitude along the waveguide,
i.e. the absence of wave group velocity, is essential
argument for the benefit of the offered model for
acoustic field excitation in ultrasonic range at under
critical frequency.
DISCUSSION
On the basis of the given quantitative
characteristics of measurements it is possible to make
energy estimations of the efficiency of oscillations
excitation. The value of acoustic pressure in solids
characterizes the volumetric density of elastic energy.
The measured maximum amplitude of pressure at
distance 15 сm. from the place of beam interaction with
target has value ~ 103 Pa. Then, taking into account the
waveguide volume, in which the energy of an elastic
standing wave is located, and the spatial distribution of
amplitude (Fig. 4), it is possible to conclude, that about
10% of beam energy was transformed to the energy of
elastic oscillations. As it follows from the diagrams of
Fig. 3, the amplitude of oscillations grows linearly with
increasing of beam current and pulse duration. It
corresponds to the model of thermoelastic mechanism
of oscillation excitation [3,4], from which it follows that
elastic wave amplitude is directly proportional to the
volumetric density of the absorbed energy.
Thus, the possibility of ultrasound generation
in solids by a pulsed beam of the charged particles is
experimentally shown. Use of proton beam has allowed
to find out the phenomenon of oscillation excitation at
low currents ~ 5 mА. The transition to intense proton
and ion beams will allow to elaborate generators of
ultrasonic oscillations with high power levels.
REFERENCES
1. Fainberg Ya.B. Some problems of plasma electronics
// Physics of plasma. - 1985.-V.11, N.11, p.1398-
1410.
2. Didenko A.N, Lihachev A.E., Kurakin I.B. Influence
of charged particles beams on a surface of metals
and alloys.- M.: Energoatomizdat, 1987.-p. I-184
3. Ranshenbach B., Hohmuth K. Generation of shock
waves by ion beam in solid target. // Phys. Status
Solid (a). - 1983. - V.75. - p.159 - 168.
4. Golota V.I. et al. About the mechanism of excitation
of elastic oscillations in substance by charged
particles beams// Ukr.Phys. Journ. - V.30. N 7.
p.1093 - 1097.
80
INTRDUCTION
EXPERIMENTAL SET UP
EXPERIMENTAL RESULTS
THEORY
DISCUSSION
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