Multikiloampere magnetron gun with secondary emission at relativistic voltage
Magnetron gun for voltage up 1000 kV and current more 1 kA was tested in pulse mode. The secondary emission nature of the cathode current was established. The identification was held basing on considered features of the exciting and on the maintenance of the secondary emission current. The gun may b...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2015 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2015
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| Цитувати: | Multikiloampere magnetron gun with secondary emission at relativistic voltage / S.A. Cherenshchykov // Вопросы атомной науки и техники. — 2015. — № 4. — С. 18-21. — Бібліогр.: 9 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859678114135670784 |
|---|---|
| author | Cherenshchykov, S.A. |
| author_facet | Cherenshchykov, S.A. |
| citation_txt | Multikiloampere magnetron gun with secondary emission at relativistic voltage / S.A. Cherenshchykov // Вопросы атомной науки и техники. — 2015. — № 4. — С. 18-21. — Бібліогр.: 9 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Magnetron gun for voltage up 1000 kV and current more 1 kA was tested in pulse mode. The secondary emission nature of the cathode current was established. The identification was held basing on considered features of the exciting and on the maintenance of the secondary emission current. The gun may be used for charge particle accel-erators and RF power sources.
Магнетронна пушка на напругу до 1000 кВ і струм понад 1 кА була випробувана в імпульсному режимі. Встановлено вторинно-емісійна природа струму пучка. Ідентифікація була проведена на основі особливостей, характерних для струму вторинної емісії. Пушка може бути використана для прискорювачів заряджених частинок і потужних джерел високої частоти.
Магнетронная пушка на напряжение до 1000 кВ и ток свыше 1 кА была испытана в импульсном режиме. Установлена вторично-эмиссионная природа тока пучка. Идентификация была проведена на основе особенностей, характерных для тока вторичной эмиссии. Пушка может быть использована для ускорителей заряженных частиц и мощных источников высокой частоты.
|
| first_indexed | 2025-11-30T16:56:21Z |
| format | Article |
| fulltext |
ISSN 1562-6016. ВАНТ. 2015. №4(98) 18
MULTIKILOAMPERE MAGNETRON GUN WITH SECONDARY
EMISSION AT RELATIVISTIC VOLTAGE
S.A. Cherenshchykov
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
E-mail: cherench@kipt.kharkov.ua
Magnetron gun for voltage up 1000 kV and current more 1 kA was tested in pulse mode. The secondary emis-
sion nature of the cathode current was established. The identification was held basing on considered features of the
exciting and on the maintenance of the secondary emission current. The gun may be used for charge particle accel-
erators and RF power sources.
PACS: 29.27.-a; 79.20.Hx
INTRODUCTION
The lifetime of modern power electron sources is not
long enough (10…10.000 hours), while other compo-
nents of the accelerator equipment serve much longer
(more than 100.000 hours). Relatively short lifetime
depend of application a heating thermionic cathode.
Nearly twenty years ago secondary emission mode in
magnetron injection gun with a cold cathode [1,2] was
achieved. Thus the Secondary Emission Magnetron In-
jection Gun (SEMIG) [3] was realized as alternative for
power electron sources with thermionic cathode.
SEMIG is a novel universal electron source with a cold
cathode. It may be used for charge particle accelerators
in injectors and power electron vacuum devices (RF and
pulse). This gun is based on an unconventional princi-
ple. The principle is the self-sustained secondary-
emission multiplication in crossed-fields. The SEMIG
may have higher current density and lifetime much
longer (up to 100.000 hours) than conventional thermi-
onic guns.
However, up to nowadays these sources didn't reach
the current and power levels featuring the most of ther-
mionic guns. In last experiments maximum secondary
emission current in crossed fields was little bit above
200 A [4]. This work deals with investigation of the
possibility to increase significantly the current and pow-
er of secondary emission sources.
1. TEST SET-UP
An experimental investigation of a secondary electron
emission in the magnetron gun (SEMIG) in pulse voltage
range of 0.3…1.0 MV was made using an accelerator
“Start”. Both microsecond and nanosecond output cir-
cuits of the accelerator were used. In both cases the stain-
less-still cathode with diameter 102 mm was used.
Fig. 1. Scheme of the microsecond output with SEMIG:
1 − 8 stage Marx generator; 2 − voltage divider;
3 − Rogowski coil for total current; 4 − insulator;
5 − cathode; 6 − solenoide; 7 − collector with copper
target; 8 − Rogowski coil for beam current
The schema of the microsecond channel is showed
on Fig. 1. The short-pulse output is shown on Fig. 2.
Fig. 2. The gun design for nanosecond mode
2. RESULTS
At microsecond output gun voltage and beam cur-
rent oscillograms are shown on Fig. 3, and a ring beam
track on a copper target is shown on Fig. 4.
Fig. 3. Gun voltage (first, up) and beam current
(second, down) at magnetic field B=0.34 T
at the microsecond output
Fig. 4. Ring beam track on a copper target
with diameter 140 mm at the microsecond output
ISSN 1562-6016. ВАНТ. 2015. №4(98) 19
Pulse fronts are restored because of recording sys-
tem of the oscilloscope gives blanks. It is due to too fast
motion of the ray on the screen.
a) B=0
b) В=0.106 T
c) В=0.160 T
d) В=0.233 T
Fig. 5. Synchronous oscillograms of the gun current
and voltage at different values of a magnetic field B are
shown. The charge voltage of the Marx generator was
32 kV
Fig. 6. Synchronous oscillograms of the gun current and
voltage at a magnetic field В=0.266 T are shown.
The charge voltage of the Marx generator was 40 kV
If current amplitude at 20-th ns on the Fig. 6 corre-
spond secondary emission mode and if apply correction
on displacement current the maximum achieved is esti-
mated as 5 kA.
3. DISCUSSION OF THE RESULTS
Emission current reaches multi kiloampere level.
Given results and their initial analysis point they can be
secondary emission currents by their nature. The emis-
sion nature must be revised due to explosive emission
can be excited at so high voltage values. Therefore, all
possible identifiers of secondary emission with com-
ments by their nature and realization are outlined by
special items.
1. No emission without magnetic field.
It is electrons would return on a cathode for the sec-
ondary emission initiation. That is possible only under
transverse magnetic field action.
There is no emission current without magnetic field
(Fig. 5,a). The total gun current is displacement current.
At voltage maximum a current is equal to zero. That is
corresponding of 20-th nanosecond. The magnetic field
turning on initiates the current at b) and c) picture of
Fig. 6. The voltage value low than 600 kV is not enough
in this case for the exciting of considerable field or ex-
plosive emission.
2. The emission pulse beginning is delayed relative-
ly voltage pulse peak.
In this case the emission pulse beginning must be
understood as difference between the total current in
Fig. 5,b,c and displacement current in Fig. 5,a.
3. The secondary emission pulse delay increase
with magnetic field value.
This is validated theoretically [5] and was observed
in experiments with magnetrons in secondary emission
mode [6].
4. The secondary emission current pulse has short-
er rise time than voltage pulse rise time.
All above current pulses obtained during the re-
search have rise time shorter than voltage pulse.
5. Rise time of the secondary emission current
pulse is shorter than drop time.
6. There is the second repeat current peak on oscil-
lograms in a few nanoseconds after rise peak.
The nature of this peak can be connected with elec-
tron flow transition to the turbulent state and with emis-
sion transition to the self-sustained mode. The emission
ISSN 1562-6016. ВАНТ. 2015. №4(98) 20
value can be higher at such transition. In any case, such
repeat peak was always observed at relatively low volt-
age nearly 60 kV [2]. It was observed on the oscillo-
scope in nanosecond resolution when the emission
mechanism doesn't require being proved. This was in
cases when the explosive emission was hard for excita-
tion due to low field and low voltage values. The sec-
ondary emission mechanism is remained only in high
vacuum conditions. Repeat peaks are observed on Fig.
5,b nearly 25-th ns and c) nearly 30-th ns.
7. The secondary emission excitation is suppressed
in high magnetic fields.
This takes place and corresponds to the Fig. 5,d. The
emission suppression in the highest magnetic field ob-
served in this research is well explained by secondary
emission nature. These follows from shape of the initia-
tion region obtained theoretically [5] in coordinates
voltage-magnetic field. It can be considered as particu-
lar case of previous item 3 with infinitely high delay.
8. The secondary emission current value is lower
considerably of the explosive emission current value.
Space charge forces limit the maximum current val-
ue. However, back electrons besides emitted electrons
present in an electron flow. Back electron increase
space charge forces in an electron flow and reduces
maximum current.
According to the known results from publications
[7], the beam current value is up to 10 kA at the explo-
sive emission in magnetic- insulated cathode. This is the
diode with same cathode material and similar electrode
diameters having operated at voltage values up to
600 kV.
For the comparison, the maximum current obtained
in present research is not higher of 5 kA in magnetic
field that points on the possibility of its secondary emis-
sion nature.
9. The current repeats the voltage shape on the
pulse peak after the current exciting.
The identifier is observed at long microsecond trian-
gle-shaped pulse (see Fig. 3). At long pulses the current-
voltage dependence is continues and is close to the or-
der of 2 that follows from the scaling theory [3]. In case
of the explosive emission the plasma boundary motion
causes the current rising at constant voltage.
10. The beam trace on the collector is hollow.
The secondary emission is initiated only from the
side surface where the electron bombardment is possi-
ble. The beam moves along lines of force of the magnet-
ic field and the collector repeats the emission region.
The experiment in low voltage secondary emission
mode confirms this conclusion. Obtained results con-
firm generally this identifier (see Fig. 4).
CONCLUSIONS
All above identifiers confirm the presence of sec-
ondary emission at high voltage values up to 600 kV.
The achieving current level is enough high for replace-
ment all types of heating cathodes in modern accelerator
facilities up to pulse power klystrons [8] and linear in-
duction accelerator. Another exotic application may be
in high current polarized electron injectors [9].
ACKNOWLEDGEMENT
I express greater thank to Dr. M.I. Gaponenko and
Dr. A.G. Ponomarev for your assistance in experiment.
The research of high current gun is supported by Uni-
versity of St. Andrews, UK and by the governments of
USA and Canada through the intergovernmental fund
STCU in frame of the project № 1968.
REFERENCES
1. S.A. Cherenshchykov, B.G. Safronov, V.S. Balagura.
Short-pulses electron guns with no heating cathodes
for linear accelerators // Problems of Atomic Science
and Technology. Series “Nuclear Physics Investiga-
tions”4(25). 1992, p. 48-51.
2. S.A. Cherenshchykov. The maltipactor emission of
electrons in the cold-cathode magnetron gun // Pro-
ceeding to reports of 13-Th. Conference of Charge
Particle Accelerators. JINR, Dubna (13-15 October
1992). Dubna, (2). 1993, p.142-144.
3. S.A. Cherenshchykov, A.N. Opanasenko, A.N.
Dovbnya, and V.V. Zakutin. Secondary emission
magnetron injection gun as high current durable
electron source. pulsed RF sources for linear collid-
ers // AIP Conf. Proc., Montauk. 1994, v. 337,
p. 350-359.
4. Y.M. Saveliev, W. Sibbett, and D.M. Parkes. Self-
excitation and operational characteristics of the
crossed-field secondary emission electron source //
Rev. Sci. Instr. 1999, v. 70, № 12, p. 4502-4514.
5. S.A. Cherenshchykov. About the magnetron start
with a cold cathode at the trailing edge of the voltage
pulse // Elektronnaja Tehnika. Series “Electronika
SVCh”. 1973, № 6, p. 20-28 (in Russian).
6. S.A. Cherenshchikov, V.D. Naumenko. Investigation
of the magnetron start with a cold secondary-
emission cathode at the trailing edge of the voltage
pulse // Izvestiya Vyschikh Uchebnykh Zavedenii
"Radiofizika", 1984, v. 27, № 2, p. 250-256 (in Rus-
sian).
7. I.Z. Gleizer, A.N. Didenko, Uj.P. Usov, V.I.
Tcvetkov, A.A. Shatanov. Cross-field current in
electron diode with magnetic insulation // Sov. Jorn.
Tech. Phys. 1980, v. 50, № 6, p. 1323-1326.
8. S.A. Cherenshchykov, A.N. Opanasenko, G.M. Iva-
nov, L.A. Makhnenko. Possible thermionic gun re-
placement with secondary emission magnetron gun
in powerful klystron amplifiers // Problems of Atom-
ic Science and Technology. Series “Nuclear Physics
Investigations”. 1997, v. 4, 5, p. 40-42.
9. S.A. Cherenshchykov. Proposal about high-current
polarized electron source with long lifetime on the
base of secondary-emission magnetron injection gun.
// The 18th Intern. Conf. on High Energy Accelera-
tors / Epochal Tsukuba, Tsukuba, Japan, March 26-
30, 2001.
Article received 30.04.2015
ISSN 1562-6016. ВАНТ. 2015. №4(98) 21
МУЛЬТИКИЛОАМПЕРНАЯ МАГНЕТРОННАЯ ПУШКА В РЕЖИМЕ ВТОРИЧНОЙ ЭМИССИИ
ПРИ РЕЛЯТИВИСТCКОМ НАПРЯЖЕНИИ
С.А. Черенщиков
Магнетронная пушка на напряжение до 1000 кВ и ток свыше 1 кА была испытана в импульсном режиме.
Установлена вторично-эмиссионная природа тока пучка. Идентификация была проведена на основе особен-
ностей, характерных для тока вторичной эмиссии. Пушка может быть использована для ускорителей заря-
женных частиц и мощных источников высокой частоты.
МУЛЬТІКІЛОАМПЕРНА МАГНЕТРОННА ПУШКА В РЕЖИМІ ВТОРИННОЇ ЕМІСІЇ
ЗА РЕЛЯТИВІСТСЬКОЮ НАПРУГОЮ
С.О. Черенщиков
Магнетронна пушка на напругу до 1000 кВ і струм понад 1 кА була випробувана в імпульсному режимі.
Встановлено вторинно-емісійна природа струму пучка. Ідентифікація була проведена на основі особливос-
тей, характерних для струму вторинної емісії. Пушка може бути використана для прискорювачів заряджених
частинок і потужних джерел високої частоти.
3. DISCUSSION OF THE RESULTS
|
| id | nasplib_isofts_kiev_ua-123456789-112243 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-11-30T16:56:21Z |
| publishDate | 2015 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Cherenshchykov, S.A. 2017-01-18T20:06:18Z 2017-01-18T20:06:18Z 2015 Multikiloampere magnetron gun with secondary emission at relativistic voltage / S.A. Cherenshchykov // Вопросы атомной науки и техники. — 2015. — № 4. — С. 18-21. — Бібліогр.: 9 назв. — англ. 1562-6016 PACS: 29.27.-a; 79.20.Hx https://nasplib.isofts.kiev.ua/handle/123456789/112243 Magnetron gun for voltage up 1000 kV and current more 1 kA was tested in pulse mode. The secondary emission nature of the cathode current was established. The identification was held basing on considered features of the exciting and on the maintenance of the secondary emission current. The gun may be used for charge particle accel-erators and RF power sources. Магнетронна пушка на напругу до 1000 кВ і струм понад 1 кА була випробувана в імпульсному режимі. Встановлено вторинно-емісійна природа струму пучка. Ідентифікація була проведена на основі особливостей, характерних для струму вторинної емісії. Пушка може бути використана для прискорювачів заряджених частинок і потужних джерел високої частоти. Магнетронная пушка на напряжение до 1000 кВ и ток свыше 1 кА была испытана в импульсном режиме. Установлена вторично-эмиссионная природа тока пучка. Идентификация была проведена на основе особенностей, характерных для тока вторичной эмиссии. Пушка может быть использована для ускорителей заряженных частиц и мощных источников высокой частоты. I express greater thank to Dr. M.I. Gaponenko and Dr. A.G. Ponomarev for your assistance in experiment. The research of high current gun is supported by University of St. Andrews, UK and by the governments of USA and Canada through the intergovernmental fund STCU in frame of the project № 1968. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Нерелятивистская электроника Multikiloampere magnetron gun with secondary emission at relativistic voltage Мультікілоамперна магнетронна пушка в режимі вторинної емісії за релятивістською напругою Мультикилоамперная магнетронная пушка в режиме вторичной эмиссии при релятивистcком напряжении Article published earlier |
| spellingShingle | Multikiloampere magnetron gun with secondary emission at relativistic voltage Cherenshchykov, S.A. Нерелятивистская электроника |
| title | Multikiloampere magnetron gun with secondary emission at relativistic voltage |
| title_alt | Мультікілоамперна магнетронна пушка в режимі вторинної емісії за релятивістською напругою Мультикилоамперная магнетронная пушка в режиме вторичной эмиссии при релятивистcком напряжении |
| title_full | Multikiloampere magnetron gun with secondary emission at relativistic voltage |
| title_fullStr | Multikiloampere magnetron gun with secondary emission at relativistic voltage |
| title_full_unstemmed | Multikiloampere magnetron gun with secondary emission at relativistic voltage |
| title_short | Multikiloampere magnetron gun with secondary emission at relativistic voltage |
| title_sort | multikiloampere magnetron gun with secondary emission at relativistic voltage |
| topic | Нерелятивистская электроника |
| topic_facet | Нерелятивистская электроника |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/112243 |
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