Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode
The possibility of increasing the current of negative hydrogen ions extracted in the longitudinal direction from Penning discharge with a metal-hydride cathode by changing potentials at the discharge cathodes is investigated. An electromagnetic filter is used to separate negative ions from the extra...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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| Цитувати: | Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, Ya.O. Hrechko, A.A. Krupka // Problems of atomic science and technology. — 2019. — № 1. — С. 190-192. — Бібліогр.: 11 назв. — англ. |
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irk-123456789-1947172023-11-29T11:50:56Z Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Hrechko, Ya.O. Krupka, A.A. Low temperature plasma and plasma technologies The possibility of increasing the current of negative hydrogen ions extracted in the longitudinal direction from Penning discharge with a metal-hydride cathode by changing potentials at the discharge cathodes is investigated. An electromagnetic filter is used to separate negative ions from the extracted flux of charged particles. A significant correlation between the extracted total current and the current of negative ions from the cathode potential was found. The optimal parameters for the effective extraction of H⁻ ions are determined. The current of the H⁻ ion beam at a level of 10 μA was obtained. Досліджується можливість збільшення струму негативних іонів водню, видобутих у поздовжньому напрямку з розряду Пенінга з металогідридним катодом шляхом зміни потенціалів на катодах розряду. Для сепарації негативних іонів, що витягаються з потоку заряджених частинок, застосовується електромагнітний фільтр. Виявлена суттєва кореляція загального струму і струму негативних іонів від потенціалу катодів. Визначено оптимальні параметри для ефективного вилучення іонів Н⁻ . Отримано струм пучка іонів Н⁻ на рівні 10 мкА. Исследуется возможность увеличения тока отрицательных ионов водорода, извлекаемых в продольном направлении из разряда Пеннинга с металлогидридным катодом, путем изменения потенциалов на катодах разряда. Для сепарации отрицательных ионов из извлекаемого потока заряженных частиц применяется электромагнитный фильтр. Обнаружена существенная корреляция извлекаемого общего тока и тока отрицательных ионов от потенциала катодов. Определены оптимальные параметры для эффективного извлечения ионов Н⁻. Получен ток пучка ионов Н⁻ на уровне 10 мкА. 2019 Article Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, Ya.O. Hrechko, A.A. Krupka // Problems of atomic science and technology. — 2019. — № 1. — С. 190-192. — Бібліогр.: 11 назв. — англ. 1562-6016 PACS: 52.80.Sm http://dspace.nbuv.gov.ua/handle/123456789/194717 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies |
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Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Hrechko, Ya.O. Krupka, A.A. Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode Вопросы атомной науки и техники |
| description |
The possibility of increasing the current of negative hydrogen ions extracted in the longitudinal direction from Penning discharge with a metal-hydride cathode by changing potentials at the discharge cathodes is investigated. An electromagnetic filter is used to separate negative ions from the extracted flux of charged particles. A significant correlation between the extracted total current and the current of negative ions from the cathode potential was found. The optimal parameters for the effective extraction of H⁻ ions are determined. The current of the H⁻ ion beam at a level of 10 μA was obtained. |
| format |
Article |
| author |
Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Hrechko, Ya.O. Krupka, A.A. |
| author_facet |
Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Hrechko, Ya.O. Krupka, A.A. |
| author_sort |
Sereda, I.N. |
| title |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode |
| title_short |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode |
| title_full |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode |
| title_fullStr |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode |
| title_full_unstemmed |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode |
| title_sort |
method of increasing the longitudnal current of н⁻ ions from pig with a metal-hydride cathode |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2019 |
| topic_facet |
Low temperature plasma and plasma technologies |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/194717 |
| citation_txt |
Method of increasing the longitudnal current of Н⁻ ions from pig with a metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, Ya.O. Hrechko, A.A. Krupka // Problems of atomic science and technology. — 2019. — № 1. — С. 190-192. — Бібліогр.: 11 назв. — англ. |
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Вопросы атомной науки и техники |
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2025-07-16T22:11:22Z |
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ISSN 1562-6016. ВАНТ. 2019. №1(119)
190 PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2019, № 1. Series: Plasma Physics (25), p. 190-192.
METHOD OF INCREASING THE LONGITUDNAL CURRENT OF
Н
–
IONS FROM PIG WITH A METAL-HYDRIDE CATHODE
I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, Ya.O. Hrechko, A.A. Krupka
V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
E-mail: igorsereda@karazin.ua
The possibility of increasing the current of negative hydrogen ions extracted in the longitudinal direction from
Penning discharge with a metal-hydride cathode by changing potentials at the discharge cathodes is investigated. An
electromagnetic filter is used to separate negative ions from the extracted flux of charged particles. A significant
correlation between the extracted total current and the current of negative ions from the cathode potential was found.
The optimal parameters for the effective extraction of H
–
ions are determined. The current of the H
–
ion beam at a
level of 10 μA was obtained.
PACS: 52.80.Sm
INTRODUCTION
Н
–
negative hydrogen ions have a high neutralization
efficiency over a wide energy range [1], they are used
both in solving the problem of controlled fusion [2], and
in the production of a number of medical radionuclides
for diagnostics and contact radiation therapy [2, 3].
The main requirements imposed on the Н
–
ions
sources are its brightness and ecological purity.
However, nowadays it is not possible to meet these two
requirements in one device, since an increase in the
efficiency of the source is achieved only by injection
cesium vapor into it [4].
For environmentally friendly use, it is necessary to
have cesium-free sources with Н
–
volume production
[5]. The formation of negative ions in these sources
occurs due to the dissociative thermal electrons
attachment to vibrationally excited hydrogen molecules
Н2
*
, which are formed due to collisions with electrons
energy of ≥ 50 eV [1, 6]. Therefore, these sources are
double-chambered, which invariably entails Н2
*
molecules loss and a decrease of the Н
–
ions production
efficiency.
Moreover, due to a change in the discharge
properties when a metal-hydride cathode is using, it
opens the possibility for longitudinal extraction of
negative ions [8, 9].
The original separation of regions with fast and slow
electrons exists in a Penning discharge: in an anodic
layer, electrons are heated to the necessary energy due
to diocotron instability, and in a cathode region there is
a large number of slow electrons obtained both from
secondary emission processes and from reflection and
scattering [7]. If one or both cathodes are made of
metal-hydride, the Н2
*
molecules are formed due to the
activation of desorbed hydrogen directly at its surface
[8]. This significantly increases the efficiency of ion
production in the discharge volume. Moreover, due to a
change in the discharge properties when a metal-hydride
cathode is using, it opens the possibility for longitudinal
extraction of negative ions [8, 9].
The purpose of this article is to investigate the
possibility of increasing the current of negative
hydrogen ions extracted in the longitudinal direction
from Penning discharge (PIG) with metal-hydride
cathode by changing the potentials at the discharge
cathodes.
1. EXPERIMENTAL SETUP
A schematic diagram of PIG with a metal-hydride
cathode and an electromagnetic filter is shown in Fig. 1.
Fig. 1. The scheme of experiment:
1 – metal-hydride cathode; 2 – anode; 3 – cathode-
reflector; 4 – electromagnetic filter
The discharge cell consisted of a water-cooled
metal-hydride cathode 1, a tubular anode 2, and a
copper cathode-reflector 3 with a central aperture.
Behind the aperture of the cathode-reflector was an
electromagnetic filter 4 for cutting off positive ions and
electrons. The calculation and design of the filter are
discussed in [10].
The metal-hydride cathode 1 had a disk shape of 5
thick and 20 mm in diameter. It was made by pressing a
hydrogen-saturated powder Zr50V50 with a copper
binder. The initial degree of hydrogen saturation was
~ 900 сm
3
under normal conditions. The metal-hydride
cathode had water cooling to stabilize the desorption
rate of hydrogen. Its temperature in the experiments did
not exceed 20
0
С, which is much lower than the
decomposition temperature of the hydride phases.
Therefore, Н2
*
desorption was determined only by the
discharge current and generally was provided by ion-
stimulated processes on the surface of the metal-hydride
[8].
It was possible to supply potentials to the discharge
cathodes to study the possibility of increasing the
Ud
1
2 3
4
Ico
ll
z
ISSN 1562-6016. ВАНТ. 2019. №1(119) 191
negative ions current. The range of variation of the
supplied potentials was( 0 ± 250) V.
2. RESULTS AND DISCUSSION
Fig. 2 demonstrates the operation of the PIG with a
metal-hydride cathode and an electromagnetic filter as
an axial source of negative hydrogen ions. This figure
shows the dependence of collector current Icoll on
discharge voltage Ud with the electromagnetic filter
turned off and on.
0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0
-30
-25
-20
-15
-10
-5
0
IIIII
H
--
current
U
MH
= 0 V
U
MH
= -50 V
Total current
U
MH
= -50 V
I co
ll
,
m
k
A
U
d
, kV
I
Fig. 2. The dependence of collector current Icoll on
discharge voltage Ud (Hz = 1000 Oe, p = 3.5∙10
-6
Torr)
Total collector current includes positive ions current,
electrons current and Н
–
negative hydrogen ions current.
The Penning discharge operates in one of three modes,
depending on anode voltage, when positive ions or
electrons predominate in the axially-directed current [8,
9].
In the mode I (Ud = 1…2 kV) the negative current is
more than 10 times higher than the current with
electromagnetic filter is switched on. Basically it's an
electron current successfully suppressed by a magnetic
filter.
Mode II (Ud ≥ 2 kV) is characterized by the fact that
ions predominate in the outflow current [9] against the
symmetrical electrical inclusion, when both cathodes
were grounded. The supply of negative bias at the
metal-hydride cathode leads to the fact that the total
current registered by the collector always has negative
values, i.e. positive ions in the outflow cannot
compensate the negative particles.
And, finally, in the mode III (Ud > 2.5 kV) a high
negative current appears again. As noted previously [8,
9], the mode III is a consequence of the use of the
metal-hydride cathode.
The shape of the curve for the ion current Н
–
with
the filter applied repeats the shape of the total current,
which agrees with the previous works [10, 11].
However, the values of the extracted current of negative
ions depend strongly on the magnitude of the electric
bias.
Fig. 3 shows the behavior of the total current on the
collector (electromagnetic filter is turned off) and the
ion current Н
–
with the filter turned on, depending on
the magnitude of the negative bias on the metal-hydride
cathode.
We can see, that the total, axially-directed current
grows with negative bias on the metal-hydride cathode.
This total current consists predominantly of electrons,
which, under the action of an electric field, are pushed
out of the cell volume toward the cathode-reflector. An
increase in the ejection field leads to an increase in the
extracted current, which agrees with the results of other
authors' experiments [7].
0 50 100 150 200 250
-100
-80
-60
-40
-20
0
I co
l ,
m
k
A
-U
MH
, V
U
d
= 4.0 kV
Total collector current
H
--
current
Fig. 3. The dependence of collector current Icoll on
negative bias on the MH-cathode (H z = 1000 Oe,
p = 3.5∙10
-6
Torr)
On the other hand, a double increase in the current
of negative ions with the filter turned on is observed
only within the limits of the change in the potential on
the metal-hydride cathode to -50 V. Further increase in
the magnitude of the negative electric bias on the metal-
hydride cathode leads to a decrease in the current of
negative ions to previous values and lower, despite on a
significant increase in the total current of charged
particles extracted in the longitudinal direction. This is
due to the fact that the region of rotation of the electron
trajectories is moved away from the surface of the
metal-hydride cathode and the efficiency of the
formation of Н
–
ions decreases by the mechanism of the
dissociative attachment of slow electrons to the
desorbed excited hydrogen molecules Н2
*
.
The supply of a positive potential to the cathode-
reflector leads to directly opposite results (Fig. 4). With
increasing of the electric bias, the current of negative
ions decreases together with the total outgoing
longitudinal current.
0 50 100 150 200 250
-20
-15
-10
-5
0
U
d
= 4.0 kV
Total collector current
H
--
current
I co
l ,
m
k
A
U
Cu
, V
Fig. 4. The dependence of collector current Icoll on
positive bias on the cathode-reflector (H z = 1000 Oe,
p = 3.5∙10
-6
Torr)
http://context.reverso.net/%D0%BF%D0%B5%D1%80%D0%B5%D0%B2%D0%BE%D0%B4/%D0%B0%D0%BD%D0%B3%D0%BB%D0%B8%D0%B9%D1%81%D0%BA%D0%B8%D0%B9-%D1%80%D1%83%D1%81%D1%81%D0%BA%D0%B8%D0%B9/as+noted+previously
192 ISSN 1562-6016. ВАНТ. 2019. №1(119)
When electric bias is applied to the cathodes, as in
the case of the previous experiments [11], the current of
the Н
–
ions weakly depends on the external magnetic
field and increases together with the discharge voltage.
CONCLUSIONS
The paper shows the possibility of increasing the
current of negative hydrogen ions extracted in the
longitudinal direction from the Penning discharge with a
metal-hydride cathode. It is established that the
maximum value of the current of extracted in the
longitudinal direction Н
–
ions is achieved by applying a
negative bias to the metal-hydride cathode in the range
from 20 to 50 V. Desorption of hydrogen from the
metal-hydride cathode in the form of vibrationally
excited Н2
*
molecules leads to intense formation of Н
–
ions. The large mean free path of the ions Н
–
provides
their unimpeded escape beyond the cell and the
formation of an axial flow of charged particles in the
longitudinal direction. Higher potentials move the
region of rotation of the electron trajectories from the
surface of the metal-hydride cathode and the efficiency
of the formation of Н
–
ions decreases.
The supply of a positive potential to the cathode-
reflector does not lead to any significant result.
The obtained current of negative hydrogen ions at
the level of 10 μA at a discharge current of 1 mA and a
discharge voltage of 4 kV can be interesting for high-
vacuum devices in which it is required to inject
continuous-type beams.
REFERENCES
1. K.N. Leung, C.A. Hauck, W.B. Kunkel,
S.R. Walhter. Optimization of H
–
production from a
small multicusp ion source // Sci. Instrum. 1989,
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2. J. Peters. Negative ions sources for high energy
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3. Th. Stammbach, S. Adam, A. Mezger,
P.A. Schmelzbach, P. Sigg. Cyclotron performance and
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Conf., Paris, 2002, p. 159-163.
4. V. Dudnikov. Thirty years of surface plasma sources
for efficient negative ion production // Rev. Sci. Instr.
2002, v. 73, № 2, p. 992-994.
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intensity negative ion sources // Nucl. Instrum. and
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6. J.R. Hiskes. Cross sections for the vibrational
excitation of the H2(X 1
∑+
g ) state via electron collisional
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8. A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko. PIG with metal-hydride cathode under
ion-stimulated desorbtion of hydrogen // Problems of
Atomic Sci. and Tech. Series “Plasma Electronics and
New Acceleration Methods” (86). 2013, № 4, p. 301-
303.
9. I.V. Borgun, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko. Experimental simulation of metal-
hydride cathode working in Penning discharge //
Problems of Atomic Sci. and Tech. Series “Plasma
Phys. (83)”. 2013, № 1, p. 228-230.
10. I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov,
I.V. Babenko, Ya.O. Hrechko, V.A. Hetman. Separation
of negative hydrogen ions from Penning discharge with
metalhydride cathode // Problems of Atomic Sci. and
Tech. Series “Plasma Phys.” (22). 2016, № 6, p. 241-
243.
11. I. Sereda, A. Tseluyko, N. Azarenkov, D. Ryab-
chikov, Ya. Hrechko. Effect of metal-hydride hydrogen
activation on longitudinal yield of negative ions from
PIG // International Journal of Hydrogen Energy. 2017,
v. 42/34, p. 21866-21870.
Article received 25.11.2018
УВЕЛИЧЕНИЕ ПРОДОЛЬНОГО ТОКА ИОНОВ Н
–
ИЗ РАЗРЯДА ПЕННИНГА
С МЕТАЛЛОГИДРИДНЫМ КАТОДОМ
И.Н. Середа, А.Ф. Целуйко, Д.Л. Рябчиков, Я.А. Гречко, А.А. Крупка
Исследуется возможность увеличения тока отрицательных ионов водорода, извлекаемых в продольном
направлении из разряда Пеннинга с металлогидридным катодом, путем изменения потенциалов на катодах
разряда. Для сепарации отрицательных ионов из извлекаемого потока заряженных частиц применяется
электромагнитный фильтр. Обнаружена существенная корреляция извлекаемого общего тока и тока
отрицательных ионов от потенциала катодов. Определены оптимальные параметры для эффективного
извлечения ионов Н
–
. Получен ток пучка ионов Н
–
на уровне 10 мкА.
ПІДВИЩЕННЯ ПОЗДОВЖНЬОГО СТРУМУ ІОНІВ Н
–
З РОЗРЯДУ ПЕНІНГА
З МЕТАЛОГІДРИДНИМ КАТОДОМ
І.М. Середа, О.Ф. Целуйко, Д.Л. Рябчиков, Я.О. Гречко, А.А. Крупка
Досліджується можливість збільшення струму негативних іонів водню, видобутих у поздовжньому
напрямку з розряду Пенінга з металогідридним катодом шляхом зміни потенціалів на катодах розряду. Для
сепарації негативних іонів, що витягаються з потоку заряджених частинок, застосовується електромагнітний
фільтр. Виявлена суттєва кореляція загального струму і струму негативних іонів від потенціалу катодів.
Визначено оптимальні параметри для ефективного вилучення іонів Н
–
. Отримано струм пучка іонів Н
–
на
рівні 10 мкА.
|