Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode
Modes of electron beam generation and parameters were investigated using a magnetron injection gun with a secondary-emission cathode depending on the magnetic field value and distribution. For the first time it has been shown that the electron current direction in such source can be varied from ax...
Gespeichert in:
| Datum: | 2006 |
|---|---|
| Hauptverfasser: | , , , |
| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2006
|
| Schriftenreihe: | Вопросы атомной науки и техники |
| Schlagworte: | |
| Online Zugang: | https://nasplib.isofts.kiev.ua/handle/123456789/79864 |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode / A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, N.A. Dovbnya // Вопросы атомной науки и техники. — 2006. — № 3. — С. 122-124. — Бібліогр.: 3 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-79864 |
|---|---|
| record_format |
dspace |
| spelling |
nasplib_isofts_kiev_ua-123456789-798642025-02-09T14:20:49Z Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode Исследование режимов генерации электронного пучка в магнетронной пушке с вторично-эмиссионным катодом Дослідження режимів генераціі електронного пучка в магнетроннній гарматі з вторинно-еміссійним катодом Dovbnya, A.N. Zakutin, V.V. Reshetnyak, N.G. Dovbnya, N.A. Ускорители заряженных частиц Modes of electron beam generation and parameters were investigated using a magnetron injection gun with a secondary-emission cathode depending on the magnetic field value and distribution. For the first time it has been shown that the electron current direction in such source can be varied from axial (along the magnetic field direction) to the radial one (across the magnetic field direction) by controlling the amplitude and magnetic field distribution with retention of secondary emission processes on the cathode. Проведено исследование различных режимов генерации и параметров электронных пучков в магнетронной пушке с холодным металлическим вторично-эмиссионным катодом в зависимости от величины и распределения магнитного поля. Впервые показано, что в таком источнике можно осуществлять изменение направления электронного тока от осевого (вдоль направления магнитного поля) к радиальному (поперек направления магнитного поля), регулируя амплитуду и распределение продольного магнитного поля при сохранении вторично-эмиссионных процессов на катоде. Проведено дослідження різних режимів генерації та параметрів електронних пучків у магнетронній гарматі з холодним металевим вторинно-емісійним катодом в залежності від розподілу магнітного поля. Вперше показано, що в такому джерелі можна отримати зміну напряму електронного струму від осьового (вздовж магнітного поля) до радіального (поперек магнітного поля), змінюючи амплітуду та розподіл магнітного поля при збереженні вторинно-емісійних процесів на катоді. 2006 Article Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode / A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, N.A. Dovbnya // Вопросы атомной науки и техники. — 2006. — № 3. — С. 122-124. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS: 41.75.Fr, 87.50.Mn https://nasplib.isofts.kiev.ua/handle/123456789/79864 en Вопросы атомной науки и техники application/pdf 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 |
Ускорители заряженных частиц Ускорители заряженных частиц |
| spellingShingle |
Ускорители заряженных частиц Ускорители заряженных частиц Dovbnya, A.N. Zakutin, V.V. Reshetnyak, N.G. Dovbnya, N.A. Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode Вопросы атомной науки и техники |
| description |
Modes of electron beam generation and parameters were investigated using a magnetron injection gun with a
secondary-emission cathode depending on the magnetic field value and distribution. For the first time it has been
shown that the electron current direction in such source can be varied from axial (along the magnetic field direction)
to the radial one (across the magnetic field direction) by controlling the amplitude and magnetic field distribution
with retention of secondary emission processes on the cathode. |
| format |
Article |
| author |
Dovbnya, A.N. Zakutin, V.V. Reshetnyak, N.G. Dovbnya, N.A. |
| author_facet |
Dovbnya, A.N. Zakutin, V.V. Reshetnyak, N.G. Dovbnya, N.A. |
| author_sort |
Dovbnya, A.N. |
| title |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| title_short |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| title_full |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| title_fullStr |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| title_full_unstemmed |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| title_sort |
studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2006 |
| topic_facet |
Ускорители заряженных частиц |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/79864 |
| citation_txt |
Studying the modes of electron beam generation in a magnetron gun with a secondary-emission cathode / A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, N.A. Dovbnya // Вопросы атомной науки и техники. — 2006. — № 3. — С. 122-124. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
AT dovbnyaan studyingthemodesofelectronbeamgenerationinamagnetrongunwithasecondaryemissioncathode AT zakutinvv studyingthemodesofelectronbeamgenerationinamagnetrongunwithasecondaryemissioncathode AT reshetnyakng studyingthemodesofelectronbeamgenerationinamagnetrongunwithasecondaryemissioncathode AT dovbnyana studyingthemodesofelectronbeamgenerationinamagnetrongunwithasecondaryemissioncathode AT dovbnyaan issledovanierežimovgeneraciiélektronnogopučkavmagnetronnojpuškesvtoričnoémissionnymkatodom AT zakutinvv issledovanierežimovgeneraciiélektronnogopučkavmagnetronnojpuškesvtoričnoémissionnymkatodom AT reshetnyakng issledovanierežimovgeneraciiélektronnogopučkavmagnetronnojpuškesvtoričnoémissionnymkatodom AT dovbnyana issledovanierežimovgeneraciiélektronnogopučkavmagnetronnojpuškesvtoričnoémissionnymkatodom AT dovbnyaan doslídžennârežimívgeneracííelektronnogopučkavmagnetronnníjgarmatízvtorinnoemíssíjnimkatodom AT zakutinvv doslídžennârežimívgeneracííelektronnogopučkavmagnetronnníjgarmatízvtorinnoemíssíjnimkatodom AT reshetnyakng doslídžennârežimívgeneracííelektronnogopučkavmagnetronnníjgarmatízvtorinnoemíssíjnimkatodom AT dovbnyana doslídžennârežimívgeneracííelektronnogopučkavmagnetronnníjgarmatízvtorinnoemíssíjnimkatodom |
| first_indexed |
2025-11-26T20:09:22Z |
| last_indexed |
2025-11-26T20:09:22Z |
| _version_ |
1849884952603131904 |
| fulltext |
STUDYING THE MODES OF ELECTRON BEAM GENERATION IN
A MAGNETRON GUN WITH A SECONDARY-EMISSION CATHODE
A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, N.A. Dovbnya
NSC KIPT, Kharkov, Ukraine
E-mail: zakutin@kipt.kharkov.ua
Modes of electron beam generation and parameters were investigated using a magnetron injection gun with a
secondary-emission cathode depending on the magnetic field value and distribution. For the first time it has been
shown that the electron current direction in such source can be varied from axial (along the magnetic field direction)
to the radial one (across the magnetic field direction) by controlling the amplitude and magnetic field distribution
with retention of secondary emission processes on the cathode.
PACS: 41.75.Fr, 87.50.Mn
1. INTRODUCTION
In the accelerating technique a secondary-emission
magnetron gun with a cold metallic secondary-emission
cathode can be used as an electron beam source in mi-
crowave devices (klystrons, gyratrons etc) [1, 2].
The guns of this type operate by the principle based
on the secondary-emission electron multiplication and
electron beam generation in the crossed electron and
magnetic fields. When a voltage pulse is applied onto
the cathode, primary electrons go out into the gap be-
tween electrodes. In the course of voltage increasing (up
to the overshoot peak) these electrons, removing from
the cathode, are accumulated in the cathode-anode gap.
On the overshoot falloff the primary electrons gain the
energy higher than the first critical potential, bombard
the cathode and provoke the processes of secondary-
emission multiplication, electron cloud formation and
electron beam generation.
The advantage of secondary-emission sources is the
absence of an intense heat, the design simplicity, and
that cathodes do not loss emission after atmosphere fill-
ing. Their main distinction from emission guns is a
high-current density per unity of the cathode cross-sec-
tional area. The secondary emission mechanism of beam
generation, due to its nondestructive action on the cath-
ode material, creates conditions for retention of emis-
sion properties of the electron source during long time
period (according to estimations ~ 100000 hours).
Therefore, of a great interest is the study on the physics
of the processes in the source with crossed electric and
magnetic fields.
The present paper describes the studies on the influ-
ence of the amplitude and longitudinal distribution mag-
netic field on the conditions of electron beam generation
and direction in the magnetron gun.
2. EXPERIMENTAL SETUP AND RE-
SEARCH METHODS
Experiments to investigate the beam parameters
were performed at the setup schematically shown in
Fig.1. A specially shaped voltage pulse with a peak at
the top (Fig.2) from a pulse modulator [3] was applied
to the gun cathode, its anode was connected to the
ground via a resistor R3 that measured the anode cur-
rent. The overshoot amplitude is adjusted within
60...100 kV, the amplitude of the flat part of the pulse
was 20...55 kV, the overshoot falloff duration was
~ 0.3 ms, the pulse duration at half-height was ~ 8 ms,
the pulse repetition rate ranged from 10 to 20 Hz.
1
2
Fig.1. Schematic of the experimental setup and direc-
tion of propagation of the electron beams. 1 – cathode
∅40 mm (Cu); 2 – anode ∅70 mm; 3 - Faraday cup;
4 - vacuum chamber; 5 − insulator. IA – radial beam;
IB - axial beam
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p.122-124.122
Fig.2. Pulses of beam current (1), anode voltage (2)
and current (3). Vertical axis scales: 1 - 0.4 A/div,
2 - 0.5 kV/div, 3 - 0.04 A/div
The studies were made on the magnetron gun of a
coaxial construction (Fig. 1), which had a secondary-
emission cathode of 70 mm in length, an anode of
140 mm in length; cathode material was copper, anode
material was steel. The cathode diameter was 40 mm.
The magnetron gun was placed in the vacuum chamber,
where a vacuum of ~ 10-6 Torr was maintained.
The magnetic field for beam generation and trans-
port was created by the solenoid (consisting of 4 sec-
tions used for adjusting the magnetic field by varying
the current value in the sections of the solenoid). The
solenoid was energized by the constant-current source.
The amplitude and longitudinal magnetic field distribu-
tion were set by changing the current value in the sec-
tions of the solenoid. Experiments were carried out with
different magnetic field distributions (decreasing, in-
creasing, bell-shaped) along the axis of the system (see
Fig.3).
The studies of beam parameters were performed by
means of a 8-channel sectionalized Faraday cup and a
computer-assisted measuring system. The measurement
error is within 1 to 2%. Measurements were taken of the
beam current from each of 8 segments of the Faraday
cup, of the cathode voltage and the anode current. These
parameters were measured and averaged over 16 volt-
age pulses following one after the other.
3. EXPERIMENTAL RESULTS AND DIS-
CUSSION
The experiments have shown that the electron beam
direction in the gun can be varied (along the gun axis or
perpendicular to it - on the radius), by adjusting the am-
plitude and distribution of the longitudinal magnetic
field. In this case, several modes of electron beam ge-
neration are realized: open (when practically all the
electron current is going along the gun axis to the Fara-
day cup), closed (when the electron current is flowing
perpendicularly to the gun axis - on the radius to the an-
ode) and intermediate (when the electron current is
flowing along the gun axis and perpendicularly to it).
In the open regime and magnetic field decreasing
along the axis of the system to the Faraday cup (Fig.3,
curve 1) at a cathode magnetic field strength of
~1300 Oe, a cathode voltage of 50 kV, the beam current
is 50 A, the anode current is 1% of the beam current
(Fig.2, curve 1). In the case of the magnetic field in-
crease in the cathode region up to 1800 Oe, the anode
current was decreasing down to the value of an order of
several milliamperes that is due to the enhancement of
the electron flux magnetic insulation.
Fig.3. Distribution of a longitudinal magnetic field HZ
and arrangement of the magnetron gun and the Fara-
day cup along the axis of the system z
In the course of experiments the existence of the
closed mode of magnetron gun operation (magnetron
mode) has been found. In this case the electron current
was flowing to the anode, the secondary-emission multi-
plication of electron being retained (see Fig.3). This
mode was attained by reducing the magnetic field H in
the cathode region down to the Hell cutoff field value of
1.1...1.2 order (HHull=6.72U1/2[ra(1 − rc
2/ra
2)]-1, where U
is the cathode voltage, rc and ra are the cathode and an-
ode radii in centimeters, respectively. At a voltage of
45 kV the Hell field is ~600 Oe).
The closed mode of magnetron gun operation is real-
ized with two magnetic field distributions − increasing
(Fig.3, curve 2) and bell-shaped (Fig.3, curve 5). In the
increasing magnetic field (the magnetic field in the
point of introduction of the cathode into the anode was
~ 660 Oe, and a average magnetic field strength on the
cathode ~ 800 Oe, on the Faraday cylinder ~ 1150 Oe)
at a cathode voltage of ~ 45 kV, the current to the anode
was ~10 A, and the current to the Faraday cup practical-
ly was absent. In the second case in the point of intro-
duction of the cathode into the anode was ~ 660 Oe, and
on the Faraday cup ~710 Oe. At a voltage of ~45 kV
and a average magnetic field strength on the cathode
~775 Oe , the current on the anode was ~5 A, and the
current to the Faraday cup was absent (Fig.4).
In the intermediate mode at a average magnetic field
strength on the cathode ~ 850 Oe and on the Faraday
cup ~980 Oe (Fig.3, curve 3) the direct beam current
was ~7 A, the anode current was ~5 A at a cathode volt-
age ~45 kV (Fig.5). The beam current and the anode
current could be adjusted by varying the magnetic field
distribution along the axis of the gun.
Besides the above described modes, we have investi-
gated the mode when in one pulse of the voltage
U ~46 kV (the magnetic field in the point of introduc-
tion of the cathode into the anode was ~540 Oe, and av-
erage magnetic field strength on the cathode ~620 Oe
(Fig.3, curve 4), of the order of Hell cutoff field, on the
Faraday cylinder ~ 800 Oe) two modes of beam genera-
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p.122-124.123
tion were realized (Fig.6): – closed mode during ~5 µs
U1~45 kV, IA ~3 A), and then at a pulse voltage de-
crease after 1.5 µs realized was: – intermediate mode
during ~2 µs (U2 ~23 kV, IB ~1 A, IA ~3 A).
Fig.4. Oscillograms of anode (radial) beams IA (mag-
netron mode) - a) in the rising magnetic field IA~10A;
U=45 kV. Horizontal –2 µs/div
Fig.5. Oscillograms for the borderland mode (IA – radi-
al beam and IB –axial beam) IA~5A; IB ~7 A,U=45 kV.
Horizontal – 2 µs/div
Fig.6. Oscillograms for the private case magnetron
mode (IA – radial beam and IB –axial beam). Horizon-
tal – 2 µs/div
4. CONCLUSIONS
The studies evidence that using the above-described
electron source it is possible to realize the mode with an
axial current only (open mode), the mode with an anode
current only (magnetron mode) and the mode with al-
most equal values of the axial and anode currents.
REFERENCES
1. Yu.Ya.Volkolupov, A.N.Dovbnya, V.V. Zakutin
et al. Generation of an electron beam in a mag-
netron gun with a secondary-emission metallic
cathode //Sov. JTF. 2001, v.71, p.98-104.
2. Yu.M. Saveliev, W. Sibbett, D.M. Parkes. Char-
acterisation of electron produced by cross-field
secondary emission diodes //J. Appl. Phys. 2001,
v.40, Part 1, N 2B, p.940-943
3. A.N. Dovbnya, N.G. Reshetnyak, V.P. Romas’ko
et al. Pulsed modulators for feeding the powerful
microwave-devices based on magnetron guns
with secondary-emission cathodes. Proc. of the
Part. Accel. Conf., Chicago, USA, 2001, v.5,
p.3759-3761.
ИССЛЕДОВАНИЕ РЕЖИМОВ ГЕНЕРАЦИИ ЭЛЕКТРОННОГО ПУЧКА В МАГНЕТРОННОЙ
ПУШКЕ С ВТОРИЧНО-ЭМИССИОННЫМ КАТОДОМ
А.Н. Довбня, В.В. Закутин, Н.Г. Решетняк, Н.А. Довбня
Проведено исследование различных режимов генерации и параметров электронных пучков в магнетрон-
ной пушке с холодным металлическим вторично-эмиссионным катодом в зависимости от величины и рас-
пределения магнитного поля. Впервые показано, что в таком источнике можно осуществлять изменение
направления электронного тока от осевого (вдоль направления магнитного поля) к радиальному (поперек
направления магнитного поля), регулируя амплитуду и распределение продольного магнитного поля при
сохранении вторично-эмиссионных процессов на катоде.
ДОСЛІДЖЕННЯ РЕЖИМІВ ГЕНЕРАЦІІ ЕЛЕКТРОННОГО ПУЧКА В МАГНЕТРОНННІЙ
ГАРМАТІ З ВТОРИННО-ЕМІССІЙНИМ КАТОДОМ
А.М. Довбня, В.В. Закутін, М.Г. Решетняк, Н.А. Довбня
Проведено дослідження різних режимів генерації та параметрів електронних пучків у магнетронній
гарматі з холодним металевим вторинно-емісійним катодом в залежності від розподілу магнітного поля.
Вперше показано, що в такому джерелі можна отримати зміну напряму електронного струму від осьового
(вздовж магнітного поля) до радіального (поперек магнітного поля), змінюючи амплітуду та розподіл
магнітного поля при збереженні вторинно-емісійних процесів на катоді.
124
Дослідження режимів генераціі електронного пучка в магнетроннній гарматі з вторинно-еміссійним катодом
|