Electron injector based on resonance system with evanescent oscillations
The article presents the design and simulated performances of an electron gun and a bunching system of the Sband injector based on a coupled cavity chain. Amplitude of the on-axis field varies substantially from the cell to the cell in the bunching system. The cell lengths are chosen to get the eff...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2004 |
| Автори: | , , , , , , , |
| Формат: | Стаття |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2004
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Electron injector based on resonance system with evanescent oscillations / M.I. Ayzatsky, E.Z. Biller, N.G. Golovko, K.Yu. Kramarenko, V.A. Kushnir, V.V. Mitrochenko, S.A. Perezhogin, V.Ph. Zhiglo // Вопросы атомной науки и техники. — 2004. — № 1. — С. 60-62. — Бібліогр.: 11 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859735495576125440 |
|---|---|
| author | Ayzatsky, M.I. Biller, E.Z. Golovko, N.G. Kramarenko, K.Yu. Kushnir, V.A. Mitrochenko, V.V. Perezhogin, S.A. Zhiglo, V.Ph. |
| author_facet | Ayzatsky, M.I. Biller, E.Z. Golovko, N.G. Kramarenko, K.Yu. Kushnir, V.A. Mitrochenko, V.V. Perezhogin, S.A. Zhiglo, V.Ph. |
| citation_txt | Electron injector based on resonance system with evanescent oscillations / M.I. Ayzatsky, E.Z. Biller, N.G. Golovko, K.Yu. Kramarenko, V.A. Kushnir, V.V. Mitrochenko, S.A. Perezhogin, V.Ph. Zhiglo // Вопросы атомной науки и техники. — 2004. — № 1. — С. 60-62. — Бібліогр.: 11 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | The article presents the design and simulated performances of an electron gun and a bunching system of the Sband injector based on a coupled cavity chain. Amplitude of the on-axis field varies substantially from the cell to the
cell in the bunching system. The cell lengths are chosen to get the effective bunching and accelerating of the beam
from the initial energy of 25 keV to the energy of about 1 MeV with the current up to 300 mA. The bunching system
can be used in electron linacs both for fundamental researches and for radiation technologies.
Приведено конструкцію та розрахункові характеристики інжектора 10-см діапазону, основаного на
ланцюжку зв’язаних резонаторів. Амплітуда поля суттєво змінюється вздовж осі системи, що дозволяє
одержати ефективне групування та прискорення пучка від початкової енергії 25 кеВ до енергії біля 1 МеВ
при струмі до 300 мА. Інжектор може бути використаний як в лінійних прискорювачах електронів для
фундаментальних досліджень, так і в прискорювачах для радіаційних технологій.
Приведены конструкция и расчетные характеристики инжектора 10-cм диапазона, основанного на цепочке связанных резонаторов. Амплитуда поля существенно изменяется вдоль оси системы, что позволяет получить эффективную группировку и ускорение пучка от начальной энергии 25 кэВ до энергии около 1 МэВ с
током до 300 мА. Инжектор может использоваться в ускорителях электронов как для фундаментальных исследований, так и для радиационных технологий.
|
| first_indexed | 2025-12-01T15:14:39Z |
| format | Article |
| fulltext |
ACCELERATOR COMPONENTS
ELECTRON INJECTOR BASED ON RESONANCE SYSTEM
WITH EVANESCENT OSCILLATIONS
M.I. Ayzatsky, E.Z. Biller, N.G. Golovko, K.Yu. Kramarenko, V.A. Kushnir, V.V. Mitrochenko,
S.A. Perezhogin, V.Ph. Zhiglo
NSC KIPT, Kharkov, Ukraine; E-mail: psa@kipt.kharkov.ua
The article presents the design and simulated performances of an electron gun and a bunching system of the S-
band injector based on a coupled cavity chain. Amplitude of the on-axis field varies substantially from the cell to the
cell in the bunching system. The cell lengths are chosen to get the effective bunching and accelerating of the beam
from the initial energy of 25 keV to the energy of about 1 MeV with the current up to 300 mA. The bunching system
can be used in electron linacs both for fundamental researches and for radiation technologies.
PACS: 12.20.-m, 13.40.-f, 13.60-Hb, 13.88.+e
1. INTRODUCTION
An injector substantially defines beam characteristics
at the linac exit. It is known, that the increasing of amp-
litude of an accelerating field at the initial stage of ac-
celeration when the phase motion of particles is not
frozen allows receiving a small phase length of bunches
at a low energy spread [1]. Bunchers, which use such a
principle, are described, for example, in [2-4]. Resonant
systems of the first and the second papers are a section
of the non-uniform biperiodic waveguide with magnetic
coupling and the third one uses the section of a non-uni-
form disk loaded waveguide (DLW) with the large at-
tenuation of a counter-propagating wave. In [5,6] it was
offered to use for this purpose a section of homogeneous
DLW exited on the frequency that lies beyond the pass-
band of the corresponding infinite waveguide.
Development of the S - band electron injector con-
sisting of a diode low-voltage (25 kV) gun and bunching
system with evanescent oscillations is the result of our
recent researches in this direction. The estimated per-
formances and outline of such an injector are presented
below. This injector has been designed for an electron
linac with output energy of 100 MeV and current of
100 mA.
2. BUNCHING SYSTEM
The buncher consists of a chain of five coupled cav-
ities with coupling through central holes for beam
passing. The sizes of the holes were selected equal to
each other. For realization of required on-axis field dis-
tribution, the operation frequency of a buncher, which
was close to the eigen frequency of the last cell, was se-
lected higher than the frequency of the "π" mode of os-
cillations of a remaining part of the buncher. In this case
the phase advance of the field per the cell equals π.
The preliminary calculations of the bunching system
were made on the basis of the self-consistent model of
weakly coupled cavities [7]. Further simulation of the
system was carried out with the SUPERFISH code [8].
To do so the configuration of a resonant system obtained
as a result of the preliminary calculations, was some-
what changed in view of a finite thickness of disks and
fringing fields at the entrance and the exit of the buncher
that were not taken into account in the preliminary cal-
culations. The purpose of calculations and simulations
was the definition of the lengths of the first and the last
cells providing the required characteristic of a beam.
The period of cells located between the first one and the
last one were chosen equal to 0.22 λ according to the
preliminary calculations. The computational electro-
dynamic characteristics of the bunching system are
shown in table 1.
Table 1. Electrodynamic characteristics of the
bunching system
Parameter Value
Operating frequency, MHz 2797.15
Quality factor 12300
Shunt impedance, MOhm/m 18
Input power, MW up to 2
Power losses in wall, MW 0.44
Maximal field on the axis, MV/m 36
To reduce influence of a space charge on the trans-
versal emittance, a distance between the electron gun
and the bunching system should be made as short as
possible. Therefore in the developed buncher the inlet
opening for injection of a beam is an anode iris of the
gun.
One of the important stages at creation of a buncher
is the development of a technique of adjusting of the res-
onant system for obtaining necessary distribution of the
on-axis field on the operating frequency. The technique
of the adjusting consists in the following. At first the fre-
quency of the "π" mode of a homogeneous segment of
the system (cells number two, three and four) is found
by the SUPERFISH code. Then the stack of three
identical cavities, restricted with cavities of half-length,
is adjusted to obtain the "π" mode on this frequency.
Then the first half-length cavity of the stack is changed
with the first cavity of a buncher and its diameter is ad-
justed to restore the frequency of the "π" mode of the
stack. After that the last half-length cavity is swapped
with the fifth cavity of the buncher. By changing its ei-
gen frequency the stack is adjusted on the operating fre-
quency of 2797.15 MHz. In such way the required on-
axis field distribution on the operating frequency can be
obtained.
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.60-62.60
mailto:psa@kipt.kharkov.ua
3. SIMULATED CHARACTERISTICS OF
THE INJECTOR
To get a substantial attenuation of the fringing fields
at the entrance of the buncher, a length of a drift pipe
between the electron gun and the first cavity should be
long enough. On the other hand, it is undesirable to use
the magnetic focusing of the beam. Therefore, the geo-
metry of gun electrodes was chosen to get a beam waist
as far as possible from the entrance of the buncher. It is
known [9], that the allowable length of a drift pipe with
the certain radius without the magnetic field depends on
a beam convergence angle at the input end of the pipe
and a current. There are optimum values of these para-
meters that ensure the maximal distance to the beam
waist. It can be found out from the expression [9]:
∫
=
1
2/1ln
)(
crR
cr
cr
R
R
dRRZ
, (1)
where Rcr is the normalized beam radius in the waist and
Z(Rcr) is the normalized distance from the anode iris (i.e.
the input end of the drift pipe) to the waist. The normal-
ized parameters are related with physical dimensions by
the following dependences:
0
rR
r
= , (2)
1/ 2
3/ 4
0
174 I zZ
U r
= ⋅ ⋅ , (3)
where I is the beam current in A, U is the cathode volt-
age in V, r.is the radius of the beam envelope, r0is the
beam radius in the anode iris.
Dependence (1) has the maximum value Zcr=1.082 at
Rcr =0.42. Thus the envelope inclination angle in the an-
ode iris R′ is 0.92. Using the given dependences, it is
possible to estimate the maximal distance from the an-
ode iris of the gun to the waist for the following condi-
tions: a radius of the cathode rc=r0=2.5 mm, a beam cur-
rent of 0.25 A, a cathode voltage of 25 kV. It yields:
Zcr=61.8 mm, Rcr=1.05 mm that allows transportation of
the beam through the buncher without magnetic focusing.
However to realize such conditions it is necessary to use
a large radius of the Wehnelt electrode and to increase
dimensions of the gun according to simulations of the
gun with the EGUN code [10]. On the other hand,
PARMELA [11] simulation of the beam dynamics with the
above-mentioned initial characteristics showed problems
of bunch formation in the buncher caused by a space
charge. Small beam radius in the waist that was located
within the third cavity hampered obtaining necessary lon-
gitudinal dimension of bunches. Therefore the final shape
and dimension of gun electrodes (see Fig.2) were chosen
taking into account beam dynamics in the buncher. Simu-
lating parameters of the gun are listed in table 2.
Table 2. Calculated parameters of the gun and
characteristic of a beam
Cathode voltage, kV -25
Cathode radius, mm 2.5
Normalized beam emittance (1 σ), π⋅mm⋅ 4.1
mrad
Distance from the front cut of the anode
aperture to the beam waist, mm
40
The beam radius in the waist, mm 1.2
Beam current, A 0.25
It was mentioned above that the numerical simula-
tions of electron beam dynamics in the buncher was car-
ried out with the PARMELA code. As the buncher is in-
tended for bunching and accelerating of a unmodulated
beam, to take into account space charge forces correctly
in simulation the input beam was represented by a bunch
with the length of 5βλ, where β is the initial relative ve-
locity of particles, λ is the operating wavelength.
The optimum lengths of the cells and their frequen-
cies were determined by successive running the SUPER-
FISH and the PARMELA codes. The design of the in-
jector was developed according to the SUPERFISH
data. The outline of the designed injector is shown in
Fig. 1. Characteristics of the output beam for a gun cur-
rent of 0.25 A are shown in table 3.
1 2
3
5
4
Fig.1. Simplified view of the injector (1 – electron gun,
2 – cooling ducts; 3 – resonant system;
4 – waveguide; 5 - tuning unit)
Fig.2 shows phase and energy spectra, emittance and
transversal profile of a beam for this case.
Table 3. Characteristics of the buncher
Input power, kW 630
Current at the injector output, А 0.23
Normalized emittance (1 σ), π⋅mm⋅mrad 19
∆ϕ (for 70 % of particles), degry 19
∆W/W (for 70 % of particles), % 5
Capture coefficient, % 91.7
Average energy, keV 821
Maximum energy, keV 913
Beam ∅ (for 70 % of particles), mm 1.69
4σx,y, mm 3.8
4. CONCLUSION
Thus, the injector system of an electron linac was de-
signed on the basis of the formulated conception on us-
age of periodic homogeneous structures with evanescent
oscillations for bunching and accelerating of an electron
beam.
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.60-62.61
Analysis of the simulated parameters of the injector
has shown that the injector can be used both in industrial
linacs and in accelerators with precise beam character-
istics. Now the injector system is at the stage of manu-
facturing. We plane to conduct detail experimental re-
search of the designed injector. The considerable prac-
tical interest represents, in particular, research of stabil-
ity of bunching system operation at formation of an in-
tensive beam.
680
510
340
170
0
1652
1239
826
413
0
50
25
0
-25
-50
252
189
126
63
0
0 444 888 1332 1776 -0.5 -0.25 0 0.25 0.5
X, cm.Phase
X̀
, m
ra
d
Ar
b.
u
ni
ts
X, cm.Energy, keV.
-180 -90 0 90 180 -0.5 -0.25 0 0.25 0.5
Ar
b.
u
ni
ts
Ar
b.
u
ni
ts
Fig. 2. Beam characteristic at the exit of the injector
REFERENCES
1. A.N. Lebedev , A.V. Shalnov // Base physics and
techniques of accelerators. M.: “Energoatom-
izdat”, 1991, 528 p. (in Russian).
2. M.S. Avilov, A.V. Novochatsky. Single bunch
compression in exponent field. // XIV Workshop
on charged particle accelerators, Protvino.
1994, v.3, p.181 – 183 (in Russian).
3. A.A. Zavadtsev, B.V. Zverev, V.E. Kaluzhny.
Manufacturing and adjusting of a buncher of a 5
MeV resonant linac // Uskoriteli. M.: “Atom-
izdat”, 1979, v.17, p.93 - 98 (in Russian).
4. S.A. Perezhogin, N.I. Ayzatsky, K.Yu. Kra-mar-
enko. Evanescent oscillations in bunching sys-
tems // Proceedings of the particle accelerators
conference, Chicago. 2001, p. 2281.
5. S.A. Perezhogin, N.I. Ayzatsky, K.Yu. Kra-mar-
enko. Bunching system base on the evanescent
waves // Problems of atomic science and tech-
nology. 2001, № 3, p.83 – 85.
6. N.I. Ayzatsky, E.Z. Biller, N.G. Golovko et al.
Bunching systems of electrons on base evanes-
cent waves // Proceedings of the particle accel-
erators conference, Portland. 2003.
7. M.I. Ayzatsky, K.Yu. Kramarenko, S.A.
Perezhogin. Beam Loading in the Standing
Wave Injector on the Base of Evanescent Wave
// Proc. of EPAC 2002, Paris, France, 2002,
p.1652 – 1654.
8. J.H. Billen and L.M. Young. POISSON SU-
PERFISH. Los Alamos National Laboratory,
LA-UR-96-1834, 1996.
9. J.R. Pierce. Theory and design of electron
beams. М., 1956, 213 p.
10. W.B. Herrmannsfeldt. EGUN: Electron Optics
Program. Stanford Linear Accelerator Center,
SLAC-PUB-6729, 1994.
11. L.M. Young. PARMELA. Los Alamos National
Laboratory, LA-UR-96-1835, 1996.
ИНЖЕКТОР ЭЛЕКТРОНОВ НА ОСНОВЕ РЕЗОНАНСНОЙ СИСТЕМЫ
С НЕРАСПРОСТРАНЯЮЩИМИСЯ КОЛЕБАНИЯМИ
Н.И. Айзацкий, Е.З. Биллер, Н.Г. Головко, К.Ю. Крамаренко, В.А. Кушнир, В.В. Митроченко,
С.А. Пережогин, В.Ф. Жигло
Приведены конструкция и расчетные характеристики инжектора 10-cм диапазона, основанного на цепоч-
ке связанных резонаторов. Амплитуда поля существенно изменяется вдоль оси системы, что позволяет полу-
чить эффективную группировку и ускорение пучка от начальной энергии 25 кэВ до энергии около 1 МэВ с
током до 300 мА. Инжектор может использоваться в ускорителях электронов как для фундаментальных ис-
следований, так и для радиационных технологий.
ІНЖЕКТОР ЕЛЕКТРОНІВ НА ОСНОВІ РЕЗОНАНСНОЇ СИСТЕМИ З КОЛИВАННЯМИ,
ЩО НЕ РОЗПОВСЮДЖУЮТЬСЯ
М.І. Айзацький, Е.З. Біллер, М.Г. Головко, К.Ю. Крамаренко, В.А. Кушнір, В.В. Митроченко,
С.А. Пережогін, В.Ф. Жигло
Приведено конструкцію та розрахункові характеристики інжектора 10-см діапазону, основаного на
ланцюжку зв’язаних резонаторів. Амплітуда поля суттєво змінюється вздовж осі системи, що дозволяє
одержати ефективне групування та прискорення пучка від початкової енергії 25 кеВ до енергії біля 1 МеВ
при струмі до 300 мА. Інжектор може бути використаний як в лінійних прискорювачах електронів для
фундаментальних досліджень, так і в прискорювачах для радіаційних технологій.
62
NSC KIPT, Kharkov, Ukraine; E-mail: psa@kipt.kharkov.ua
1. INTRODUCTION
2. BUNCHING SYSTEM
Parameter
3. SIMULATED CHARACTERISTICS OF THE INJECTOR
4. CONCLUSION
REFERENCES
|
| id | nasplib_isofts_kiev_ua-123456789-78573 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-01T15:14:39Z |
| publishDate | 2004 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Ayzatsky, M.I. Biller, E.Z. Golovko, N.G. Kramarenko, K.Yu. Kushnir, V.A. Mitrochenko, V.V. Perezhogin, S.A. Zhiglo, V.Ph. 2015-03-19T08:05:14Z 2015-03-19T08:05:14Z 2004 Electron injector based on resonance system with evanescent oscillations / M.I. Ayzatsky, E.Z. Biller, N.G. Golovko, K.Yu. Kramarenko, V.A. Kushnir, V.V. Mitrochenko, S.A. Perezhogin, V.Ph. Zhiglo // Вопросы атомной науки и техники. — 2004. — № 1. — С. 60-62. — Бібліогр.: 11 назв. — англ. 1562-6016 PACS: 12.20.-m, 13.40.-f, 13.60-Hb, 13.88.+e https://nasplib.isofts.kiev.ua/handle/123456789/78573 The article presents the design and simulated performances of an electron gun and a bunching system of the Sband injector based on a coupled cavity chain. Amplitude of the on-axis field varies substantially from the cell to the cell in the bunching system. The cell lengths are chosen to get the effective bunching and accelerating of the beam from the initial energy of 25 keV to the energy of about 1 MeV with the current up to 300 mA. The bunching system can be used in electron linacs both for fundamental researches and for radiation technologies. Приведено конструкцію та розрахункові характеристики інжектора 10-см діапазону, основаного на ланцюжку зв’язаних резонаторів. Амплітуда поля суттєво змінюється вздовж осі системи, що дозволяє одержати ефективне групування та прискорення пучка від початкової енергії 25 кеВ до енергії біля 1 МеВ при струмі до 300 мА. Інжектор може бути використаний як в лінійних прискорювачах електронів для фундаментальних досліджень, так і в прискорювачах для радіаційних технологій. Приведены конструкция и расчетные характеристики инжектора 10-cм диапазона, основанного на цепочке связанных резонаторов. Амплитуда поля существенно изменяется вдоль оси системы, что позволяет получить эффективную группировку и ускорение пучка от начальной энергии 25 кэВ до энергии около 1 МэВ с током до 300 мА. Инжектор может использоваться в ускорителях электронов как для фундаментальных исследований, так и для радиационных технологий. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Элементы ускорителей Electron injector based on resonance system with evanescent oscillations Інжектор електронів на основі резонансної системи з коливаннями, що не розповсюджуються Инжектор электронов на основе резонансной системы с нераспространяющимися колебаниями Article published earlier |
| spellingShingle | Electron injector based on resonance system with evanescent oscillations Ayzatsky, M.I. Biller, E.Z. Golovko, N.G. Kramarenko, K.Yu. Kushnir, V.A. Mitrochenko, V.V. Perezhogin, S.A. Zhiglo, V.Ph. Элементы ускорителей |
| title | Electron injector based on resonance system with evanescent oscillations |
| title_alt | Інжектор електронів на основі резонансної системи з коливаннями, що не розповсюджуються Инжектор электронов на основе резонансной системы с нераспространяющимися колебаниями |
| title_full | Electron injector based on resonance system with evanescent oscillations |
| title_fullStr | Electron injector based on resonance system with evanescent oscillations |
| title_full_unstemmed | Electron injector based on resonance system with evanescent oscillations |
| title_short | Electron injector based on resonance system with evanescent oscillations |
| title_sort | electron injector based on resonance system with evanescent oscillations |
| topic | Элементы ускорителей |
| topic_facet | Элементы ускорителей |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/78573 |
| work_keys_str_mv | AT ayzatskymi electroninjectorbasedonresonancesystemwithevanescentoscillations AT billerez electroninjectorbasedonresonancesystemwithevanescentoscillations AT golovkong electroninjectorbasedonresonancesystemwithevanescentoscillations AT kramarenkokyu electroninjectorbasedonresonancesystemwithevanescentoscillations AT kushnirva electroninjectorbasedonresonancesystemwithevanescentoscillations AT mitrochenkovv electroninjectorbasedonresonancesystemwithevanescentoscillations AT perezhoginsa electroninjectorbasedonresonancesystemwithevanescentoscillations AT zhiglovph electroninjectorbasedonresonancesystemwithevanescentoscillations AT ayzatskymi ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT billerez ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT golovkong ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT kramarenkokyu ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT kushnirva ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT mitrochenkovv ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT perezhoginsa ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT zhiglovph ínžektorelektronívnaosnovírezonansnoísistemizkolivannâmiŝonerozpovsûdžuûtʹsâ AT ayzatskymi inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT billerez inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT golovkong inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT kramarenkokyu inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT kushnirva inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT mitrochenkovv inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT perezhoginsa inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi AT zhiglovph inžektorélektronovnaosnoverezonansnoisistemysnerasprostranâûŝimisâkolebaniâmi |