200 keV electron beam pulse source for the complex VEPP-5 preinjector
The electron beam source based on GS-34 valve cathode-grid unit with oxide cathode of 12 mm in diameter is described. Originally the high voltage DC source was used to supply the gun. The cathode emission characteristic was reduced by the vacuum breakdowns during gun operation. So the necessity of d...
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| Дата: | 2001 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
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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: | 200 keV electron beam pulse source for the complex VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, A.A. Korepanov, A.R. Frolov, A.V. Tsyganov // Вопросы атомной науки и техники. — 2001. — № 3. — С. 111-112. — Бібліогр.: 3 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
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irk-123456789-792482015-03-31T03:02:43Z 200 keV electron beam pulse source for the complex VEPP-5 preinjector Akimov, V.E. Kazarezov, I.V. Korepanov, A.A. Frolov, A.R. Tsyganov, A.V. The electron beam source based on GS-34 valve cathode-grid unit with oxide cathode of 12 mm in diameter is described. Originally the high voltage DC source was used to supply the gun. The cathode emission characteristic was reduced by the vacuum breakdowns during gun operation. So the necessity of decreasing a high voltage from 200 kV to 140 kV has appeared. The use of the pulse transformer based gun supply with a pulse duration of ~1 mcs provided the gun operation without breakdowns at a voltage of 200 kV and pulse repetition rate up to 50 Hz. At present time the electron source is operated at the complex VEPP-5 preinjector. 2001 Article 200 keV electron beam pulse source for the complex VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, A.A. Korepanov, A.R. Frolov, A.V. Tsyganov // Вопросы атомной науки и техники. — 2001. — № 3. — С. 111-112. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS numbers: 29.25.Bx http://dspace.nbuv.gov.ua/handle/123456789/79248 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 |
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DSpace DC |
| language |
English |
| description |
The electron beam source based on GS-34 valve cathode-grid unit with oxide cathode of 12 mm in diameter is described. Originally the high voltage DC source was used to supply the gun. The cathode emission characteristic was reduced by the vacuum breakdowns during gun operation. So the necessity of decreasing a high voltage from 200 kV to 140 kV has appeared. The use of the pulse transformer based gun supply with a pulse duration of ~1 mcs provided the gun operation without breakdowns at a voltage of 200 kV and pulse repetition rate up to 50 Hz. At present time the electron source is operated at the complex VEPP-5 preinjector. |
| format |
Article |
| author |
Akimov, V.E. Kazarezov, I.V. Korepanov, A.A. Frolov, A.R. Tsyganov, A.V. |
| spellingShingle |
Akimov, V.E. Kazarezov, I.V. Korepanov, A.A. Frolov, A.R. Tsyganov, A.V. 200 keV electron beam pulse source for the complex VEPP-5 preinjector Вопросы атомной науки и техники |
| author_facet |
Akimov, V.E. Kazarezov, I.V. Korepanov, A.A. Frolov, A.R. Tsyganov, A.V. |
| author_sort |
Akimov, V.E. |
| title |
200 keV electron beam pulse source for the complex VEPP-5 preinjector |
| title_short |
200 keV electron beam pulse source for the complex VEPP-5 preinjector |
| title_full |
200 keV electron beam pulse source for the complex VEPP-5 preinjector |
| title_fullStr |
200 keV electron beam pulse source for the complex VEPP-5 preinjector |
| title_full_unstemmed |
200 keV electron beam pulse source for the complex VEPP-5 preinjector |
| title_sort |
200 kev electron beam pulse source for the complex vepp-5 preinjector |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2001 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79248 |
| citation_txt |
200 keV electron beam pulse source for the complex VEPP-5 preinjector / V.E. Akimov, I.V. Kazarezov, A.A. Korepanov, A.R. Frolov, A.V. Tsyganov // Вопросы атомной науки и техники. — 2001. — № 3. — С. 111-112. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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| first_indexed |
2025-07-06T03:17:37Z |
| last_indexed |
2025-07-06T03:17:37Z |
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1836865927923105792 |
| fulltext |
200 KEV ELECTRON BEAM PULSE SOURCE FOR
THE COMPLEX VEPP-5 PREINJECTOR
V.E. Akimov, I.V. Kazarezov, A.A. Korepanov, A.R. Frolov, A.V. Tsyganov
Institute of Nuclear Physics SB RAS
630090 Novosibirsk, Russia, Lavrentiev Ave., 11,
e-mail: I.V.Kazarezov@inp.nsk.su
The electron beam source based on GS-34 valve cathode-grid unit with oxide cathode of 12 mm in diameter is de-
scribed. Originally the high voltage DC source was used to supply the gun. The cathode emission characteristic was
reduced by the vacuum breakdowns during gun operation. So the necessity of decreasing a high voltage from
200 kV to 140 kV has appeared. The use of the pulse transformer based gun supply with a pulse duration of ~1 mcs
provided the gun operation without breakdowns at a voltage of 200 kV and pulse repetition rate up to 50 Hz. At
present time the electron source is operated at the complex VEPP-5 preinjector.
PACS numbers: 29.25.Bx
To generate electron bunches in the complex
VEPP-5 preinjector electron beam source with the fol-
lowing parameters is required:
Electron energy 200 keV
Beam current (peak) 10 А
Pulse duration (at halfheight) 2-3 ns
Pulse repetition rate 50 Hz
Emittance, no more than 0.01 π cm rad
Synchronization instability 100 ps
Energy spread <1 %
At the initial stage the DC power supply based on a
high voltage cascade generator [1] was used. Operation
of such a source over a long period of time showed that
vacuum isolation breakdowns forced to decrease opera-
tion voltage from 200 kV to 130-140 kV. Therefore to
provide required energy the high-voltage pulse genera-
tor on the base of pulse transformer [2] was developed.
1 HIGH VOLTAGE GENERATOR CIRCUIT
Fig. 1 represents the simplified generator circuit.
The charging of the primary circuit storage C1 comes
from high voltage adjustable power supply with a volt-
age up to 10 kV.
Fig. 1. Simplified circuit of the electron beam
source.
After triggering the thyratron TGI1-1000/25 the ca-
pacitance C1 discharges through PT primary winding to
the secondary circuit capacitance consisting of PT dis-
tributed capacitance (~80 pF), electron gun and gun
control unit capacitances (~120 pF). For complete ener-
gy transfer from С1 to the secondary contour reduced
values of primary and secondary circuits capacitances
should be equal therefore capacitance C1 was chosen
about 100 nF. To obtain a pulse rise time on the gun no
more then 0.5 mcs the total primary circuit inductance
and reduced PT leackage inductance were chosen no
more then 300 nH. The pulse fall time generation is pro-
vided by PT core saturation. Both PT core section and
number of turns as well as a reset current are chosen so
that the induction in the core is average out to the satu-
ration induction in a moment of pulse top. A circuit
formed of the resistor R2 and diode VD1 placed in par-
allel to the load is used to limit the subsequent inverse
overvoltage on a load.
2 PULSE ELECTRON SOURCE DESIGN
The sketch of the source is shown in Fig. 2. A gun, a
beam focusing system, a gun control unit and a high
voltage pulse generator are located on a rack. The cath-
ode grid unit 6 is fixed on a sectioned metall-ceramic
transfer isolator 7 made from UF-46 ceramics, which is
similar to one used in ELV series industrial accelerators.
The length of the isolator is 20 cm. All components
wich are located under high voltage – gun isolator 7,
control unit 8, pulse transformer 12 – are arranged in-
side common tank 9. SF6 gas under pressure of 1.7 atm
is used as an insulation.
The basic part of the high voltage pulse generator is
PT. Structurally PT is carried out similarly [3]. The core
is of continuous type and carried out from a tape of
50NP permalloy by thickness of 10 microns that allows
to reduce magnetization losses in PT to a minimum. The
PT secondary winding is carried out from two symmet-
ric parallel parts. The high-voltage edges of windings
adjoin each other, therefore the electrical field between
windings is practically homogeneous in such design.
Using two parallel branches of a secondary winding al-
lows to use them for the cathode filament and grid con-
trol power supply. For reduction of leakage inductance
the secondary winding is of cone type in a radial direc-
tion. The absence of a skeleton on an internal generating
line of the secondary winding excludes an opportunity
of breakdowns along the surface.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №3.
Серия: Ядерно-физические исследования (38), с. 111-112.
111
Fig. 2. Electron source sketch:
1 – corrector coil, 2 – second magnetic lens,
3 - vacuum valve, 4 – wall current monitor, 5 – first
magnetic lens, 6 – cathode grid unit, 7 – sectioned
isolator, 8 – gun control unit, 9 – tank, 10 – gun
control unit power supply, 11 – pulse transformer,
12 – thyratron and primary storage unit, 13 – high
vacuum pump NMD-0.4.
3 ELECTRON GUN
GS-34 lamp cathode grid unit with oxide cathode of
12 mm diameter is used in electron gun. Low grid volt-
age values required for this unit simplify the task of
forming short control pulse and provide beam with low
emmitance. In rated mode the gun gives close to parallel
beam (divergence angle is about 50 mrad for a 10 A
beam) at the output.
Beam focusing system comprises two magnetic lens-
es 5, 2 (Fig. 2) and beam position corrector 1. Valve 3
providing cut off the gun from the injector and resistive
wall current monitor 4 are located between lenses. Esti-
mations show that beam size at the subharmonic bunch-
er input does not exceed 10 mm during the whole pulse.
Vacuum in the gun is provided by vacuum pump of
NMD-0.4 type.
4 GUN CONTROL UNIT
One of the complex block of the source – gun con-
trol unit, forming pulse voltage between grid and cath-
ode. To decrease the breakdown influence on reliability
of the unit the scheme with ''grounded'' grid is utilized.
This unit solves two tasks – forming of beam current
pulse of required amplitude and duration and at the
same time providing synchronism of gun triggering
from the complex control system. The pulse current am-
plitude can be regulated from 0 up to 10 A by bias volt-
age variation.
The unit is made of transistors and integral circuits,
its block-scheme is shown in Fig. 3. Special unit with
resolution of 100 ps was developed to control the pulse
of current time correlation. Synchronization pulses are
fed to the unit by fiber cable.
Fig. 3. Block-scheme of gun current control.
5 TEST RESULTS
To the present days breakdown free electrical tests
on a voltage 230 kV, pulse repetition rate 50 Hz was
carried out. The source is used for test and tuning exper-
iments of preinjector complex. Electron gun voltage and
beam current waveforms are shown in Fig. 4.
0,0 0,5 1,0 1,5 2,0
-0,5
0,0
0,5
1,0
1,5
2,0
2,5
3,0
0,0 0,5 1,0 1,5 2,0
-250
-200
-150
-100
-50
0
50
100
0,850 0,855 0,860 0,865 0,870 0,875 0,880 0,885 0,890 0,895 0,900
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
G
un
c
ur
re
nt
, A
time, mcs
G
un
v
ol
ta
ge
, k
V
time, mcs
G
un
c
ur
re
nt
, A
Fig. 4. Beam current and gun voltage oscillogramms.
In the conclusion it is necessary to note that A.Gon-
charov, A.Sharapa, A.Shemyakin took part in the devel-
oping of the electron gun at the design stage. Designing
of the first version of the source was done by B.S-
mirnov.
REFERENCES
1. Physical project of VEPP-5 complex, Budker Insti-
tute of Nuclear Physics, Novosibirsk, 1995.
2. V.E.Akimov, I.V.Kazarezov, A.A.Korepanov.
200 kV pulse generator for a power supply of the
electron gun for the complex VEPP-5 preinjector //
VANT, Issue: NPR (35). 1999, # 4, p. 46-49.
3. I.Kazarezov, G.Krainov. Pulse transformer for NLC
klystron // Proc of Third Annual Klystron-Modula-
tor Workshop, June 23-25, 1998, Workshop paper.
112
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