Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices
The paper presents the design description and the results of tests of the block combining an electron gun and a getter - ion pump, providing plasma - forming gas evacuation from the slow - wave structures. The block is designed for use in high-power beam - plasma devices. The construction under cons...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2008
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| Назва видання: | Вопросы атомной науки и техники |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices / A.N. Antonov, A.M. Yegorov, O.F. Kovpik, E.A. Kornilov, V.G. Svichensky // Вопросы атомной науки и техники. — 2008. — № 6. — С. 153-155. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-1107652017-01-07T03:03:25Z Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices Antonov, A.N. Yegorov, A.M. Kovpik, O.F. Kornilov, E.A. Svichensky, V.G. Plasma electronics The paper presents the design description and the results of tests of the block combining an electron gun and a getter - ion pump, providing plasma - forming gas evacuation from the slow - wave structures. The block is designed for use in high-power beam - plasma devices. The construction under consideration minimizes the overall block dimensions. The block, in the assembly of the generator with a hybrid slow-wave structure (a sequence of inductively coupled resonators and a plasma - filled transport channel) provides the generation of stochastic oscillations in the tenth-centimeter wavelength range in the frequency band of 1 GHz, 40 kW microwave power in the continuous mode of operation and 100 kW in the pulse of 4 ms duration. Описана конструкція блоку поєднучого електронну гармату і гетеро - іонний насос для потужних пучково – плазмових приладів, забезпечующого відкачку плазмостворуючого газу із уповільнюючих структур. Така конструкція мінімізує малогабаритні параметри блоку. Блок, що входить до складу генератора з гібридною уповільнюючою структурою - ланцюгом індуктивно зв’язаних резонаторів, заповнених плазмою, забезпечує генерацію стохастичних коливань в десятисантіметровому діапазоні довжини хвиль в смузі коливань 1 ГГц в постійному режимі роботи 40 і 100 кВт в імпульсі тривалістю 4 мс. Описана конструкция блока, объединяющего электрону пушку, и геттерно - ионный насос, для мощных пучково – плазменных приборов, обеспечивающий откачку плазмообразующего газа из замедляющих структур. Такая конструкция минимизирует весогабаритные параметры блока. Блок, входящий в состав генератора с гибридной замедляющей структурой - цепочкой индуктивно связанных резонаторов, заполненной плазмой, обеспечивает генерацию стохастических колебаний в десятисантиметровом диапазоне длин волн в полосе частот 1 ГГц, при непрерывном режиме работы 40 и 100 кВт в импульсе длительностью 4 м. 2008 Article Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices / A.N. Antonov, A.M. Yegorov, O.F. Kovpik, E.A. Kornilov, V.G. Svichensky // Вопросы атомной науки и техники. — 2008. — № 6. — С. 153-155. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 52 40 Mj http://dspace.nbuv.gov.ua/handle/123456789/110765 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 |
| collection |
DSpace DC |
| language |
English |
| topic |
Plasma electronics Plasma electronics |
| spellingShingle |
Plasma electronics Plasma electronics Antonov, A.N. Yegorov, A.M. Kovpik, O.F. Kornilov, E.A. Svichensky, V.G. Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices Вопросы атомной науки и техники |
| description |
The paper presents the design description and the results of tests of the block combining an electron gun and a getter - ion pump, providing plasma - forming gas evacuation from the slow - wave structures. The block is designed for use in high-power beam - plasma devices. The construction under consideration minimizes the overall block dimensions. The block, in the assembly of the generator with a hybrid slow-wave structure (a sequence of inductively coupled resonators and a plasma - filled transport channel) provides the generation of stochastic oscillations in the tenth-centimeter wavelength range in the frequency band of 1 GHz, 40 kW microwave power in the continuous mode of operation and 100 kW in the pulse of 4 ms duration. |
| format |
Article |
| author |
Antonov, A.N. Yegorov, A.M. Kovpik, O.F. Kornilov, E.A. Svichensky, V.G. |
| author_facet |
Antonov, A.N. Yegorov, A.M. Kovpik, O.F. Kornilov, E.A. Svichensky, V.G. |
| author_sort |
Antonov, A.N. |
| title |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| title_short |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| title_full |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| title_fullStr |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| title_full_unstemmed |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| title_sort |
block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2008 |
| topic_facet |
Plasma electronics |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/110765 |
| citation_txt |
Block of an electron gun combined with a getter - ion pump designed for high - power beam - plasma microwave devices / A.N. Antonov, A.M. Yegorov, O.F. Kovpik, E.A. Kornilov, V.G. Svichensky // Вопросы атомной науки и техники. — 2008. — № 6. — С. 153-155. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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| fulltext |
BLOCK OF AN ELECTRON GUN COMBINED WITH A GETTER - ION
PUMP DESIGNED FOR HIGH - POWER BEAM - PLASMA MICROWAVE
DEVICES
A.N. Antonov, A.M. Yegorov, O.F. Kovpik, E.A. Kornilov, V.G. Svichensky
National Science Center “Kharkov Institute of Physics and Technology”,
61108 Kharkov, Ukraine, e-mail: kovpik@kipt.kharkov.ua
The paper presents the design description and the results of tests of the block combining an electron gun and a
getter - ion pump, providing plasma - forming gas evacuation from the slow - wave structures. The block is designed for
use in high-power beam - plasma devices. The construction under consideration minimizes the overall block
dimensions. The block, in the assembly of the generator with a hybrid slow-wave structure (a sequence of inductively
coupled resonators and a plasma - filled transport channel) provides the generation of stochastic oscillations in the
tenth-centimeter wavelength range in the frequency band of 1 GHz, 40 kW microwave power in the continuous mode of
operation and 100 kW in the pulse of 4 ms duration.
PACS: 52 40 Mj
In microwave devices of the non-relativistic plasma
electronics – beam - plasma generator, beam - plasma
amplifiers - the plasma filling of slow - wave structures,
placed in the magnetic field, is an essential element
forming a hybrid slow - wave structure. The devices with
a hybrid slow - wave structure possess unique features:
volume type of excited waves, broad spectrum of
oscillations, and high value of the power of oscillations
generated and amplified in the continuous and pulse
modes of operation [1,2].
The problem of plasma - forming gas evacuation into
such devices calls for the necessity to develop new
evacuation units used in them in order to minimize the
weight and overall dimensions. The development of such
devices is related with plasma - creation techniques.
A simple method of plasma creation is the use of a
beam - plasma discharge in the magnetic field. The
electron beam, used as an energy source for excitation of
microwave oscillations, initiates the plasma and interacts
with it [3].
The electron operation, at accelerating potentials of
tens kilovolts, is possible in vacuum not worse than 107–
10-5 Torr, while in the hybrid slow - wave system the
pressure should be of about 10-5–10-4 Torr. Consequently,
there are contradicting requirements to the pressure for
plasma creation and to the gun operating conditions
which can be satisfied only by creating the pressure
difference between the gun and the area of interaction
with the plasma. This condition can be reached by
evacuating the plasma - forming gas through the transport
channel between these areas which provides the pressure
difference. However, the length and the cross - section of
the transport channel can not be chosen arbitrary
considering the physical processes taking place in these
devices. An acceptable length of the transport channel is
determined by the mechanism of excitation of microwave
oscillations by an electron beam in the plasma. To
increase the channel length is not optimum decision
because it can lead to the transition of the microwave
oscillation excitation by a beam from the hydrodynamic
stage into the kinetic one in the slow - wave structure and,
consequently, the efficiency of a device might be
decreased.
The relaxation length of the ~ 40 kV no relativistic
electron beam, used in this generator, in the
hydrodynamic mode with a maximum efficiency was
from 0.26 to 0.6 m according to estimations of [4]. (Here
the relaxation length is the distance where the beam
transfers its energy into excited microwave oscillations).
The given estimate determines a required acceptable
length of the device where the hydrodynamic stage of
beam interaction will be kept. Taking into account that the
slow-wave structure length can be 0.2 m, the transport
channel length should not exceed ~ 0.06 – 0.1 m [3].
The channel cross - section is determined by the
electron beam diameter. For devices under consideration
in the tenth-centimeter wavelength range with a power of
tens kilowatts this diameter can reach a centimeter. The
use of such a large transport channel for these devices is
possible due to excitation in them of volume waves. The
channel cross - section of this value permits to obtain
high - power microwave oscillations. Therefore, in the
hybrid slow - wave structure the transport channel can be
increased, as compared to the vacuum devices of the
indicated wavelength range [1,2,4].
As is obvious from the foregoing, a necessary evacuation
rate is 0.07 − 0.11 m3 s-1 at a pressure from 10-7 to 10-5 Torr.
An important problem is the choice of plasma - forming
gas. To minimize the neutral gas in leakage into the gun
region it is desirable to have a maximally heavy gas, the
leakage rate decreases with gas mass increasing. For
“sealed - off” devices the most suitable evacuation method is
the getter technique. A simple getter, titanium, absorbs well,
in main, hydrogen and nitrogen. Therefore, nitrogen was
chosen as a plasma-forming gas. This choice was due to the
property of nitrogen to form with titanium a
high - temperature compound which does not release the
absorbed gas during the repeated vacuum training of the
device. However, the getter alone can not provide a
sufficient evacuation rate in the high vacuum. Therefore, as
an evacuation device we selected a getter-ion pump
permitting to reach an acceptable evacuation rate in the high
vacuum. A getter-ion pump means a device having the
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2008. № 6. 153
Series: Plasma Physics (14), p. 153-155.
mailto:kovpik@kipt.kharkov.ua
electrons ionizing the evacuated gas and the getter atoms
being accelerated by the electrical field onto its gettering
surfaces.
For minimization of the weight and overall
dimensions of beam - plasma devices it is necessary to
combine an electron gun with an evacuation device. Thus,
the large-scale vacuum line from the pump to the gun can
be excluded. Therefore, constructively the block is
designed so, that the electron gun is placed in its center
and the getter - ion pump is arranged coaxially to the gun.
In this combination the operation of the high - voltage
electron gun should not be influenced by the pump and
vice versa. Necessary conditions were provided in the
block under consideration. The schematic of an electron
gun combined with a getter-ion pump is shown in Fig 1.
The vacuum housing of the block (1) is made of
non - magnetic steel Х18Н9Т (Russian Standard) in the
form of a cylinder having 0.38 m diameter, 0.26 m height
with cone face ends. The housing has double walls with
welded partition plates between them being the bearing
elements and, simultaneously, its cooling system. The
cylindrical internal surface has radial crimps with a radius
of curvature to 0.015 m. The getter surface to be cooled is
0.57 m2.
One of the block face ends is made in the form of a
removable flange (2) with a metallic wedge - type seal.
On the flange, also made in the form of a truncated being
cooled cone, mounted are the elements of the electron gun
(3) and of the pump (5), a vacuum-sensing device and a
valve with a metallic sealing for detachment of the device
from the vacuum post after the training cycle (5). Such a
dismountable block construction allows one to perform
design improvement and to repair its elements.
The electron gun is a triode with an intermediate
anode installed under the positive potential of about 1-
3 kV for slowing down the ion component drifting along
the channel from the slow-wave structure to the gun. The
gun cathodes (3), made of LaB6, are provided with
electron heating. The intermediate anode is made in the
form of a cylinder composed of jalousie designed to
increase the rate of gas evacuation from the gun region.
The intermediate face end of the anode is made of
tantalum in the form of a hemisphere. In the inside of the
cylinder – intermediate anode, two cathodes and a
tungsten directly heating heater fixed at tubes are
coaxially installed. To screen the electron gun from the
sputtered getter it is placed into the double perforated
titanium screen.
The gun has a system of electron beam positioning
relatively to the transport channel in the evacuated state.
Deposition of titanium onto the pump guttering surface
is performed by three V-shaped wire elements of 4 mm in
diameter made of iodide-titanium. They are installed
uniformly on a circle of the removable flange so that the
internal pump surface is covered. The voltage at the
sputters Uр=10 V, the current is 137 А.
Gas ionization in the pump volume is performed by
electrons emitted from the direct - heating wire tantalum
cathode (3) at the positive potential of the grid (4). The
cylindrical pump grid arranged coaxially to the electron
gun occupies entirely the free block volume. The grid
transparence is ~ 95%.
The electron source of the getter - ion pump is made in
the form of a single block placed in the grid volume.
Fig.1 Schematic of the block
Acceleration of gas ions ionized by electrons in the
pump grid volume is provided by its positive potential.
The grid current is 1 ampere at a voltage of 2 kV. The
positive potential of the intermediate electron gun anode
is also applied to the getter-ion pump grid. Thus, the
number of sources necessary for block power supply can
be reduced. The evacuation rate of the pump of
0.008 – 0.11 m3 s-1 at a pressure of 10-7 − 10-5 Torr is
increasing to 1 m3s-1 at 5·10-4 Torr. The plot of the
evacuation rate of the ion - getter pump as a function of
the pressure for nitrogen being evacuated is given in
Fig.2.
Fig.2. Evacuation rate of the getter - ion pump as a
function of the pressure for nitrogen being evacuated
The construction of the block, the electron gun and the
pump is made on the whole in the metal-ceramic version.
The pump was started after heating the block and the
generator together at a temperature of ~ 450о 120 hours
(not less). The initial titanium sputtering onto the block
gettering surfaces was carried out at a wall temperature of
350 - 450 оand a pressure of 10-7 Torr. The block was
heated by means of the pump electron current and
external heaters, all the vacuum generator system being
heated. Then the generator was cooled. After reaching a
nominal rating, the intercepting vacuum valve was closed
from the training bench, and the generator was operating
in the independent mode.
154
The residual pressure in the oscillator was 10-
8 – 10-9 Torr.
The running hours of the block in the oscillator
structure is 950 hours.
The use of such a block in the generator structure in
the continuous mode of operation permitted to obtain the
40 kW stochastic oscillations in the tenth-centimeter
wavelength range in the frequency in the frequency band
of 1 GHz, 40 kW microwave power in the continuous
mode of operation and 100 kW in the pulse of 4 ms
duration.
Authors are grateful V.A. Miroshnichenko,
Yu.A. Degtyar and M.G. Sokolov the help in research of
the block consisting an electronic gun and the pump.
REFERENCES
1. A.N. Antonov, Yu.P. Bliokh, Yu.A. Degtjar et al.
Beam - plasma generator based on interaction of an
electronic beam with plasma limited by the
waveguide structure - chain of inductive connected
resonators // Plasma Physics. 1994. v. 20, № 9, p.
177-781 (in Russian).
2. A.N. Antonov, A.K. Berezin , Yu.P. Bliokh et al. To
the electrodynamics of the hybrid plasma-waveguide
structures (theory and experiment) // Proc. of 10 - th
Int.Conf. on High Power Particle Beams (BEAMS-
1994). June 20-24 1994, San – Diego. v. I. p. 260-
263.
3. N.G. Maciborko, I.N. Onishchenko, Ya.B. Fainberg
et al. About occurrence of turbulence at interaction
hydrodynamic a beam with plasma // Journal of
Experimental and Theoretical Physics. 1970, v. 12,
p. 874-880 (in Russian).
4. E.A. Kornilov, O.F. Kovpik, Ya.B. Fainberg, I.F.
Harchenko. Mechanism of formation of plasma at
development of beam - plasma instability // Journal
of Technical Physics. 1970, v. 12, p. 874-880 (in
Russian).
Article received 2.10.08.
БЛОК ЭЛЕКТРОННОЙ ПУШКИ, СОВМЕЩЕННОЙ С ГЕТТЕРНО - ИОННЫМ НАСОСОМ
ДЛЯ МОЩНЫХ ПУЧКОВО - ПЛАЗМЕННЫХ СВЕРХВЫСОКОЧАСТОТНЫХ ПРИБОРОВ
А.Н. Антонов, А.М. Егоров, О.Ф. Ковпик, Е.А. Корнилов, В.Г. Свиченский
Описана конструкция блока, объединяющего электрону пушку, и геттерно - ионный насос, для мощных
пучково – плазменных приборов, обеспечивающий откачку плазмообразующего газа из замедляющих структур.
Такая конструкция минимизирует весогабаритные параметры блока. Блок, входящий в состав генератора с
гибридной замедляющей структурой - цепочкой индуктивно связанных резонаторов, заполненной плазмой,
обеспечивает генерацию стохастических колебаний в десятисантиметровом диапазоне длин волн в полосе частот
1 ГГц, при непрерывном режиме работы 40 и 100 кВт в импульсе длительностью 4 м.
БЛОК ЕЛЕКТРОННОЇ ГАРМАТИ, ПОЄДНАНОЇ З ГЕТТЕРНО - ІОННИМ НАСОСОМ
ДЛЯ ПОТУЖНИХ ПУЧКОВО – ПЛАЗМОВИХ НАДВИСОКОЧАСТОТНИХ ПРИЛАДІВ
О.М. Антонов, О.М. Егоров, О.Ф. Ковпік Є.О. Корнілов, В.Г. Свіченський
Описана конструкція блоку поєднучого електронну гармату і гетеро - іонний насос для потужних
пучково – плазмових приладів, забезпечующого відкачку плазмостворуючого газу із уповільнюючих структур.
Така конструкція мінімізує малогабаритні параметри блоку. Блок, що входить до складу генератора з гібридною
уповільнюючою структурою - ланцюгом індуктивно зв’язаних резонаторів, заповнених плазмою, забезпечує
генерацію стохастичних коливань в десятисантіметровому діапазоні довжини хвиль в смузі коливань 1 ГГц в
постійному режимі роботи 40 і 100 кВт в імпульсі тривалістю 4 мс.
155
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