Electron-optical system of 200 kV gun for the VEPP-5 preinjector
The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm...
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| Zitieren: | Electron-optical system of 200 kV gun for the VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, G.I. Kuznetsov, M.A. Tiunov // Вопросы атомной науки и техники. — 2004. — № 1. — С. 128-130. — Бібліогр.: 5 назв. — англ. |
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Akimov, V.E. Kazarezov, I.V. Kuznetsov, G.I. Tiunov, M.A. 2015-03-24T14:57:59Z 2015-03-24T14:57:59Z 2004 Electron-optical system of 200 kV gun for the VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, G.I. Kuznetsov, M.A. Tiunov // Вопросы атомной науки и техники. — 2004. — № 1. — С. 128-130. — Бібліогр.: 5 назв. — англ. 1562-6016 PACS: 29.17.+w https://nasplib.isofts.kiev.ua/handle/123456789/78967 The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current control is performed by means of molybdenum equipotential grid with the cell size 0.4·0.4 mm and optical transparency of about 0.68. The experimental results obtained are in good agreement with project parameters. Описано електронну гармату з новою електронно-оптичною системою, що відповідає проектним параметрам передінжектора VEPP-5. Гармата дає струм 10 А с тривалістю імпульсу 2...3 нс на напіввисоті і з енергією електронів 200 кеВ. Гармата має диспергуємий катод діаметром 20 мм і радіусом сфери 100 мм. Керування здійснюється за допомогою молібденової еквіпотенційної сітки з коміркою розміром 0.4·0.4 мм і оптичною прозорістю близько 0.68. Експериментально отримані результати знаходяться у відповідності з проектними параметрами. Описана электронная пушка с новой электронно-оптической системой, соответствующая проектным параметрам предынжектора VEPP-5. Пушка дает ток 10 А с длительностью импульса 2…3 нс на полувысоте и с энергией электронов 200 кэВ. Пушка имеет диспергируемый катод диаметром 20 мм и сферическим радиусом сферы 100 мм. Управление осуществляется посредством молибденовой эквипотенциальной сетки с ячейкой размером 0.4·0.4 мм и оптической прозрачности около 0.68. Экспериментальные полученные результаты находятся в хорошем соответствии с проектными параметрами. The authors are very grateful to P.V.Logachev for fruitful discussion as well as to M.A.Batazova for her assistance in preparation of this paper. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Элементы ускорителей Electron-optical system of 200 kV gun for the VEPP-5 preinjector Електронно-оптична система 200 кВ гармати для прединжектора VEPP-5 Электронно-оптическая система 200 кВ пушки для предынжектора VEPP-5 Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector |
| spellingShingle |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector Akimov, V.E. Kazarezov, I.V. Kuznetsov, G.I. Tiunov, M.A. Элементы ускорителей |
| title_short |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector |
| title_full |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector |
| title_fullStr |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector |
| title_full_unstemmed |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector |
| title_sort |
electron-optical system of 200 kv gun for the vepp-5 preinjector |
| author |
Akimov, V.E. Kazarezov, I.V. Kuznetsov, G.I. Tiunov, M.A. |
| author_facet |
Akimov, V.E. Kazarezov, I.V. Kuznetsov, G.I. Tiunov, M.A. |
| topic |
Элементы ускорителей |
| topic_facet |
Элементы ускорителей |
| publishDate |
2004 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Електронно-оптична система 200 кВ гармати для прединжектора VEPP-5 Электронно-оптическая система 200 кВ пушки для предынжектора VEPP-5 |
| description |
The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is
described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current control is performed by means of molybdenum equipotential grid with the cell size 0.4·0.4 mm and optical transparency
of about 0.68. The experimental results obtained are in good agreement with project parameters.
Описано електронну гармату з новою електронно-оптичною системою, що відповідає проектним
параметрам передінжектора VEPP-5. Гармата дає струм 10 А с тривалістю імпульсу 2...3 нс на напіввисоті і
з енергією електронів 200 кеВ. Гармата має диспергуємий катод діаметром 20 мм і радіусом сфери 100 мм.
Керування здійснюється за допомогою молібденової еквіпотенційної сітки з коміркою розміром 0.4·0.4 мм і
оптичною прозорістю близько 0.68. Експериментально отримані результати знаходяться у відповідності з
проектними параметрами.
Описана электронная пушка с новой электронно-оптической системой, соответствующая проектным параметрам предынжектора VEPP-5. Пушка дает ток 10 А с длительностью импульса 2…3 нс на полувысоте и
с энергией электронов 200 кэВ. Пушка имеет диспергируемый катод диаметром 20 мм и сферическим радиусом сферы 100 мм. Управление осуществляется посредством молибденовой эквипотенциальной сетки с
ячейкой размером 0.4·0.4 мм и оптической прозрачности около 0.68. Экспериментальные полученные результаты находятся в хорошем соответствии с проектными параметрами.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/78967 |
| citation_txt |
Electron-optical system of 200 kV gun for the VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, G.I. Kuznetsov, M.A. Tiunov // Вопросы атомной науки и техники. — 2004. — № 1. — С. 128-130. — Бібліогр.: 5 назв. — англ. |
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| first_indexed |
2025-11-25T21:33:37Z |
| last_indexed |
2025-11-25T21:33:37Z |
| _version_ |
1850559582994169856 |
| fulltext |
ELECTRON-OPTICAL SYSTEM OF 200 kV GUN
FOR THE VEPP-5 PREINJECTOR
V.E. Akimov, I.V. Kazarezov, G.I. Kuznetsov, M.A. Tiunov
Institute of Nuclear Physics, SB RAS, 630090, Novosibirsk, Russia, 11, Lavrentiev av.;
E-mail: I.V.Kazarezov@inp.nsk.su
The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is
described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron en-
ergy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current con-
trol is performed by means of molybdenum equipotential grid with the cell size 0.4·0.4 mm and optical transparency
of about 0.68. The experimental results obtained are in good agreement with project parameters.
PACS: 29.17.+w
1. INTRODUCTION
In the Вudker Institute of Nuclear Physics, SB RAS,
Novosibirsk, according to the VEPP-5 preinjector
project [1] a first version of its preinjector has been de-
veloped and put into operation [2]. To generate electron
bunches, an electron gun operating at a stable mode of
200 kV, 2A current amplitude is used [3].
As an electron emitter, the 12.5 mm in diameter ox-
ide cathode-grid unit based on the GS-34B valve is used
[3]. This gun does not provide a required current and
also is not durable enough, so a new electron source
with enhanced parameters listed below has been con-
structed.
a)a
b )
B ( z )E ( z )
b
Fig.1. Electron gun:
General view (1 – cathode-grid unit with focusing electrode; 2 – electrodes; 3 – accelerating tube; 4 – ion
pump; 5 – anode; 6 - magnetic lenses; 7 – gate; 8 – bed frame; 9 – vacuum channel; 10 – collector) (а);
results of simulation (electric and magnetic field axial distributions, trajectories of electrons, at the right upper
corner – current density distribution and phase portrait of the beam at the entrance to RF accelerator) (б)
Electron energy .......................200 keV
Bunch current amplitude .........10 A
Pulse duration (at half-height) ..2...3 ns
Pulse repetition rate ..................50 Hz
Beam emittance less than ..........0.01 π cm rad
The cathode life-time is more than 104 hours.
In the paper the results of computer simulation, the
electron gun design, and experimental data are present-
ed.
2. OPTICAL SIMULATIONS
The sketch of the electron gun and its electron-opti-
cal system are presented.
The electron gun based on the accelerating tube
along with focusing electrodes is manufactured on the
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.128-130.128
flange as one spear unit (1). A dispenser spherical cath-
ode unit produced in “Thorium”, Moscow [4], is used as
an electron emitter. The cathode has the diameter 20
mm, spherical radius of 100.4 mm. The cathode allows
4-5 disassemblies of the gun and exposure on the air
without its emission degradation. The control grid has
spherical radius 100 mm, sell size 0.4·0.4 mm, width of
crosspieces 0.06 mm, it is made of 100 µm molybdenum.
The distance for the cold cathode-grid is 0.4 mm.
The accelerating tube (3) consists of 6 welded alu-
mino-oxide ceramic rings with outer and inner diame-
ters 150 mm and 135 mm respectively. The electrodes
are made of Kovar, while the spacers of copper. The ac-
celerating electrodes (2), which along with the focusing
ones and anode are forming the electron-optical system,
are fixed into the tube electrode recesses.
The beam transportation and its matching to the lin-
ear accelerate input is performed by means of two mag-
netic lenses (6). Nanosecond beam pick-ups (are not
shown in Fig.1) allow recording a value and a shape of
the current pulses with required time precision. Vacuum
gate (7) installed between the gun and the linear acceler-
ator permits one to fix on the preinjector the operational
gun previously prepared and tested on the separated fa-
cilities. The gun and the vacuum channel are on the
frame. Gun pumping during its activating phase is car-
rying through the vacuum channel (9) by additional
pumps.
Simulations of the electron-optical system as well as
of the cathode-grid unit have been made by the comput-
er code UltraSAM [5] in electrostatic approximation.
One of the alternatives of the beam propagation from
the grid surface to the collector is shown in Fig.1,b. The
current density on the grid is uniform. The initial elec-
tron energy is 0.17 keV. The aim was to minimize the
beam emittance at the gun entrance. To simulate the
separate cell of the control grid an axially symmetric
model of a square sell with equal area was chosen. The
full amount of such cells is about 2000. The cathode-
grid gap in simulation was put 0.3 mm, taking into ac-
count a thermal drift of 0.1 mm. In Fig.2 one can see the
results of computing. At the grid the electrical potential
area is 7 kV/cm and the grid voltage is 0.17 kV.
Fig.2. Results of simulation of the model of square grid
cell. Between neighbor equipotential lines is 20 kV, tra-
jectories of electrons, current density distribution and
phase portrait of the beam at 0.8 mm from the grid (the
right upper corner)
In Fig.3 the calculated dependences between cathode
current, collector current and grid one and grid voltage
are presented. One could also see the maximum relative
spread of transverse velocities of electrons at the grid
plane versus Ug. For these simulations a model of the
cathode–grid unit described above was employed.
0
4
8
12
16
20
24
28
-30 0 30 60 90 120 150 180 210 240
Ugrid, V
I,
A
Vr
/V
z*
10
0
calculated cathode current
calculated grid current
calculated Vr/Vz*100
measured cathode current
measured grid current
calculated beam current
Fig.3. Results of simulations and measured VA plot of
the new 200 kV gun for VEPP5 preinjector
3. EXPERIMENTAL RESULTS
The cathode supplies pulse current is up to 8 A at the
heating power of 39 W, at 45 W it goes up to 16 A, at
54 W it is 26 A at the partially temperature limited
mode.
In the test facility at the cathode voltage Uк=50 kV,
the bias grid voltage was 1.02·10-3 of cathode voltage.
In this mode we had in the collector 1.2 of 1.75 A from
the cathode, that was 0.685 of path current flow at grid
optical transparency 0.68, that corresponds to 9.6 A at
Uk=200 kV.
The measured cathode current and grid current for
different grid voltages are presented in Fig.3. Measure-
ments were performed at 50 kV on the cathode and were
related to Uk=200 kV according to “3/2” law.
The measured cathode-grid capacitance on flange
leads-in is 23 pF. The grid bias voltage at 200 kV of the
anode one comprises 11…12 V and depends on gun
heating power.
The thermal drift of the grid depends on the operat-
ing heating power. The gap between the cathode surface
and the greed is 0.33…0.35 mm while 0.4…0.42 mm in
cold condition.
The grid emission at 50 W of heating power is
~5 µA at the pressure 4·10-6 Pa. When we use one pump
of 10 l/sec capacity, the vacuum is 5·10-5 Pa at 50 W of
heating power.
CONCLUSION
The results of experimental testing of the new gun
allow us to conclude that its parameters achieved are
perfectly match to these required for the VEPP-5 prein-
jector project. When controlling systems are manufac-
tured and tested in the operating mode, the electron
source will be fixed on the preinjector.
The authors are very grateful to P.V.Logachev for
fruitful discussion as well as to M.A.Batazova for her
assistance in preparation of this paper.
REFERENCES
1. Physical project of the complex VEPP-5, Budker
Institute of Nuclear Physics Novosibirsk, 1995.
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.128-130.129
2. M.S.Avilov, V.E.Akimov, A.V.Alexandrov,
A.V.Antoshin, I.V.Kazarezov et al. Testing of the
accelerating section of the preinjector Vepp-5 //
Proc.of XVII conference on charged particle accel-
erators, 17-20 October 2000. Protvino, 2000, v.1,
p.71-78.
3. V.E. Akimov, I.V. Kazarezov A.A. Korepanov еt
al. 200 keV electron beam pulse source for the
complex VEPP-5 preinjector // Voprosy Atomnoj
Nauki i Tekhniki. Series: “Yaderno-fizicheskiye
issledovaniya”. 2001, № 3, p.111-112.
4. I.G.Artyukh, M.V.Kalinin, B.Kh.Kantselson et al.
Cathodes for electro-vacuum devices // Zarubezh-
naya radioelectronika. 1998, № 5, p.72-77 (in Rus-
sian).
5. A.V. Ivanov, M.A. Tiunov. ULTRASAM - 2D
Code for Simulation of Electron Guns with Ultra
High Precision // Proceedings of the EPAC2002,
Paris. 2002, p.1634-1636.
ЭЛЕКТРОННО-ОПТИЧЕСКАЯ СИСТЕМА 200 кВ ПУШКИ ДЛЯ ПРЕДЫНЖЕКТОРА VEPP-5
А.Е. Акимов, И.В. Казарезов, Г.И. Кузнецов, М.А. Тиунов
Описана электронная пушка с новой электронно-оптической системой, соответствующая проектным па-
раметрам предынжектора VEPP-5. Пушка дает ток 10 А с длительностью импульса 2…3 нс на полувысоте и
с энергией электронов 200 кэВ. Пушка имеет диспергируемый катод диаметром 20 мм и сферическим ради-
усом сферы 100 мм. Управление осуществляется посредством молибденовой эквипотенциальной сетки с
ячейкой размером 0.4·0.4 мм и оптической прозрачности около 0.68. Экспериментальные полученные ре-
зультаты находятся в хорошем соответствии с проектными параметрами
ЕЛЕКТРОННО-ОПТИЧНА СИСТЕМА 200 кВ ГАРМАТИ ДЛЯ ПРЕДИНЖЕКТОРА VEPP-5
А.Є. Акімов, І.В. Казарезов, Г.І. Кузнєцов, М.А. Тіунов
Описано електронну гармату з новою електронно-оптичною системою, що відповідає проектним
параметрам передінжектора VEPP-5. Гармата дає струм 10 А с тривалістю імпульсу 2...3 нс на напіввисоті і
з енергією електронів 200 кеВ. Гармата має диспергуємий катод діаметром 20 мм і радіусом сфери 100 мм.
Керування здійснюється за допомогою молібденової еквіпотенційної сітки з коміркою розміром 0.4·0.4 мм і
оптичною прозорістю близько 0.68. Експериментально отримані результати знаходяться у відповідності з
проектними параметрами.
130
The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current control is performed by means of molybdenum equipotential grid with the cell size 0.4·0.4 mm and optical transparency of about 0.68. The experimental results obtained are in good agreement with project parameters.
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