Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode
The experimental studies of the Penning-type charged particle source with metal hydride cathode are presented. In order to determine the mechanisms responsible for the emission of negative particles in the axial direction, the influence of different hydrogen feeding methods were studied. To simulate...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2014
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| Cite this: | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, I.V. Borgun, M.O. Goncharenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 201-203. — Бібліогр.: 5 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860098269482319872 |
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| author | Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Borgun, I.V. Goncharenko, M.O. |
| author_facet | Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Borgun, I.V. Goncharenko, M.O. |
| citation_txt | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, I.V. Borgun, M.O. Goncharenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 201-203. — Бібліогр.: 5 назв. — англ. |
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| description | The experimental studies of the Penning-type charged particle source with metal hydride cathode are presented. In order to determine the mechanisms responsible for the emission of negative particles in the axial direction, the influence of different hydrogen feeding methods were studied. To simulate hydrogen desorption the cathode of special design was applied and to force only hydrogen ion-stimulated desorption the forced cooling metal hydride cathode was used.
Представлены результаты экспериментального исследования источника заряженных частиц пеннинговского типа с металлогидридным катодом. С целью определения факторов, ответственных за эмиссию отрицательных частиц в аксиальном направлении, изучено влияние разных способов напуска водорода в ячейку. Для имитации десорбции применены катоды специальной конструкции и ион-стимулированная десорбция водорода за счет принудительного охлаждения металлогидридного катода.
Представлено результати експериментального дослідження джерела заряджених частинок пенінговського типу з металогідридним катодом. З метою визначення факторів, що відповідають за емісію негативних частинок в аксіальному напрямку, вивчено вплив різних способів напуску водню в проміжок. Для імітації десорбції застосовані катода спеціальної конструкції і іон-стимульована десорбція водню за рахунок примусового охолодження металогідридного катоду.
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| first_indexed | 2025-12-07T17:27:18Z |
| format | Article |
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ISSN 1562-6016. ВАНТ. 2014. №6(94)
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2014, №6. Series: Plasma Physics (20), p. 201-203. 201
INFLUENCE OF HYDROGEN SUPPLY ON EMISSIVE
CHARACTERISTICS OF PIG WITH METAL-HYDRIDE CATHODE
I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, I.V. Borgun, M.O. Goncharenko
V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
E-mail: igorsereda@karazin.ua
The experimental studies of the Penning-type charged particle source with metal hydride cathode are presented. In
order to determine the mechanisms responsible for the emission of negative particles in the axial direction, the influence of
different hydrogen feeding methods were studied. To simulate hydrogen desorption the cathode of special design was
applied and to force only hydrogen ion-stimulated desorption the forced cooling metal hydride cathode was used.
PACS: 52.80.Sm
INTRODUCTION
Application of metal-hydrides (MH) based on Zr-V
alloys capable of reversibly storing hydrogen isotopes
as cathode material in plasma sources is known to have
a number of advantages as compared with common
supply systems. Hydrogen desorption from MH is
caused by both heating of the sample and the current
discharge influence. It allows not only to safety store
hydrogen and realize the local gas feeding but to also to
raise the efficiency of a source due to metal-hydride
hydrogen activation [1]. For instance, experiments with
Penning-type ion source using MH-cathode revealed an
additional (third) regime of the source working in the
range where high discharge voltage appears [2]. In this
regime, only the ions from the MH-cathode side are
kept on in the axial flow, but the electrons were
registered on the opposite side. The negative current
increased along with the discharge voltage and at some
point it exceeded the ion current. It made possible, for
instance, to get compensated beam for technological
applications. The problem in source designing was the
strong dependence of desorbed neutral hydrogen flow
on MH-cathode temperature. It made the stabilizing the
discharge regime a difficult problem. This paper is
devoted to solving the problem of pressure stabilizing
and determining the mechanisms responsible for axial
electron emission from the discharge for improving the
source characteristics.
1. EXPERIMENTAL SETUP
The experimental setup is based on Penning-type
discharge cell represented in Fig. 1.
Three types of cathodes were used in the
experiment. The first one is the MH-cathode pressed
from powder mixture of saturated with hydrogen
Fig. 1. The scheme of discharge cell:
1 – anode; 2 – MH-cathode; 3 – cathode-holder;
4 – thermocouple; 5 – cathode-reflector; 6 – collector
Zr50V50Hx alloy and copper stuff with initial saturation
of hydrogen about 900 cm
3
under normal conditions
was just set in discharge. The second one is the same
MH-cathode but with water-cooling. The third one is a
copper cathode with hydrogen supply for simulation of
hydrogen desorption. All types of cathodes have the
same spatial dimensions: 2.0 cm in diameter and 0.5 cm
thick. The cathode-reflector is made of copper and has
an aperture at the center with 0.5 cm in diameter. In
check experiments two solid copper cathodes were used.
A collector or an electrostatic energy-analyzer can be
set behind the aperture in cathode-reflector.
In hydrogen desorption simulation experiments,
balloon let hydrogen in locally through thin holes in the
working surface of the copper cathode. The ratio between
local (through cathode) and additional (in vacuum
chamber) flows of supplied hydrogen as well as intensity
of external magnetic field were picked the same as in [2]
at third regime of discharge with MH-cathode.
The residual pressure in vacuum chamber did not
exceed 5 10
-6
Torr. The investigations were carried out at
the pressure of 10
-6
…10
-4
Torr. A working pressure that
is higher that the residual one was achieved by initial
balloon hydrogen supply into the vacuum chamber.
2. RESULTS AND DISCUSSION
The typical dependences of collector current on
discharge voltage are shown in Fig. 2 for the cases of MH-
cathode with water-cooling and without the water-cooling,
cathode with supply and solid cathodes (check
experiment).
0 1 2 3 4 5 6
-60
-40
-20
0
20 4
U
d
, kV
3
2
1
I c
o
l
,
A
Fig. 2. Dependence of collector current on discharge
voltage for different cathodes, P = 3∙10
-5
Torr,
H = 1 kOe: 1 – MH cathode; 2 – water-cooled MH
cathode; 3 – simulation experiment; 4 – check
experiment
1
2
3
4
water
5 6
202 ISSN 1562-6016. ВАНТ. 2014. №6(94)
One can see that the third regime of the source with
MH-cathode starts at about 3.0 kV (see lines 1 and 2 in
Fig. 2) in both cases: with and without water-cooling.
The higher voltages for which the current changes its
sign in the case of MH-cathode without cooling are
obviously explained by the effect of pressure on ion
quantity in the output flow. In simulation experiments,
the current on collector diminishes as well (see line 3 in
Fig. 2). As it was revealed by retarding field method,
there are no electrons in output flow in simulation
experiment. (This differs the simulation experiment
from the case of MH-cathodes in which current
reduction results from the electron part in output ion-
electron flow increasing.) So, there is no third regime in
simulation experiment as well as in check experiments.
This proves the determining role of desorbed hydrogen
in producing the axial electron flows at heightened
discharge voltages.
Transition to the third regime is followed by step
increase of HF-oscillation frequency and amplitude of
diocotron type instability [3]. Taking into account a well-
known expression for the frequency of diocotron
oscillations f ~ Er / H [4], the raise of oscillation
frequency is explained by radial electric field (Er)
increasing caused by redistribution of axial (Ez) and radial
(Er) electric fields in favor of Er (potential on the axis of
the system decreases). Wherein redistribution of radial
(Er) and axial (Ez) electric fields provides the primary
ionization in anode layer. Comparison of experiments
with MH-cathode and the simulation ones revealed that
desorbed hydrogen flow makes an impact on spatial
distribution of axial electric field (Ez) in the gap and
gradient of Ez arising [3]. Simulation experiments lead to
Ez gradient appearance only.
So, the deciding factor for axial electron flow
emission is the HF-instability developing under the
conditions of hydrogen desorption from MH-cathode in
non-equilibrium state. Electron emission only from one
side is caused by additional neutral hydrogen flow from
the direction of a cathode. At total hydrogen outlet from
MH-cathode the third regime disappears, and discharge
behaves as in case of usual cathodes.
But the problem with designing a working source is
the strong dependence of desorbed hydrogen flow on
MH-cathode temperature that makes it difficult to
stabilize the discharge regime. From this point of view
MH-cathode cooling could solve the problem. This
could allow stabilizing the discharge working pressure
and eliminating the hydrogen kick caused by
uncontrolled thermal decomposition of hydride phases
[5]. Low temperature of MH-cathode (lower than
hydride phases decomposition one) ensures hydrogen
desorption only due to ion-stimulated processes. This
provides the possibility to control the hydrogen
desorption rate by current discharge and work only on
hydrogen desorbed from the cathode. This will reduce
the hydrogen consumption and rise the source life time.
Further experiments should be carried out to make sure
of discharge characteristics not changing.
The typical collector currents are presented in Fig. 3
for the case in which the discharge works only on the
hydrogen desorbed from MH-cathode. One can see that
the discharge behaves in the same way as in previous
0 1 2 3 4 5 6
-60
-40
-20
0
20
3
2
I c
o
l
,
A
U
d
, kV
1
Fig. 3. Dependence of collectors current on discharge
voltage for different cathodes, P = 5∙10
-6
Torr,
H = 1 kOe: 1 – MH cathode; 2 – water-cooled MH
cathode; 3 – check experiment
experiments with the MH-cathode with an additional
external hydrogen supply into vacuum chamber (see
lines 1 and 2 in Fig. 2). Moreover, pressure increase
does not sufficiently shift the voltage for the discharge
transition to the third regime. All these issues give an
opportunity to work only on hydrogen desorbed from
MH-cathode without external feeding and apply the data
obtained in previous experiments. MH-cathode water-
cooling is only the tool for pressure maintaining here [4].
Fig. 4 shows ion energy distribution function (IEDF)
for all cathodes used in the experiments and for both
cases of hydrogen supply: due to desorption from MH-
cathode only and with addition external hydrogen
supply into vacuum chamber.
Discharge voltages for measuring the IEDF were
chosen in the following way. Figures for Ud = 2.5 kV
correspond to the second discharge regime, when only
ions are registered in axial direction [2]. Figures for
Ud = 3 kV correspond to the transition to third regime
(electrons start to appear in the output flow). And figures
for Ud = 3.5 kV correspond to the third regime of
discharge working (output axial current has negative
sign). Note that under residual pressure of P = 5·10
-6
Torr
there is no data to compare with. That is why only data
for MH-cathodes is presented on upper figures in Fig. 4.
One can see qualitatively the same behavior of
distribution function in check and simulation
experiments (see lines 1 and 2 respectively in Fig. 4).
The only difference is the particles quantity output from
the discharge. In the case of MH-cathode the
distribution function shifts and widens towards the
lower values of energy at discharge transition to the
third regime. This is due to widening of intensive
ionization field from anode layer to discharge axis with
lower values of space potential. This phenomenon is the
mostly pronounced in the case of MH-cathode without
water-cooling (see line 3 in Fig. 4). In This case
intensive hydrogen desorption in non-equilibrium state
takes place under the influence of discharge current that
leads to ionization intensification near the axis. In the case
of hydrogen desorption only due to ion-stimulated
processes (see line 4 in Fig. 4) the situation is the same but
the quantity of desorbed hydrogen is sufficiently lower
and, accordingly, the distribution function widens not so
much. Data differences (see line 2 in Fig. 4) for
simulation experiments are explained by the ratio
between local and additional feeding of hydrogen that
was maintained to be the same in a whole range of
203 ISSN 1562-6016. ВАНТ. 2014. №6(94)
500 1000 1500 2000 2500
0,0000
0,0002
0,0004
0,0006
0,0008
0,0010
4a
rb
.
u
n
it
s
E, eV
U
d
= 2.5 kV
P = 5*10
-6
Torr
3
500 1000 1500 2000 2500
0,0000
0,0004
0,0008
0,0012
0,0016
0,0020
4
a
rb
.
u
n
it
s
E, eV
U
d
= 3 kV
P = 5*10
-6
Torr
3
500 1000 1500 2000 2500
0,0000
0,0005
0,0010
0,0015
0,0020
4
a
rb
.
u
n
it
s
E, eV
U
d
= 3.5 kV
P = 5*10
-6
Torr
3
800 1200 1600 2000 2400 2800
0,000
0,001
0,002
0,003
0,004
0,005
0,006
0,007
4
3
2
a
rb
.
u
n
it
E, eV
U
d
= 2.5 kV
P = 3*10
-5
Torr
1
800 1200 1600 2000 2400 2800
0,000
0,002
0,004
0,006
0,008
0,010
4
3
2
a
rb
.
u
n
it
E, eV
U
d
= 3 kV
P = 3*10
-5
Torr
1
800 1200 1600 2000 2400 2800
0,000
0,002
0,004
0,006
0,008
0,010
4
3
2a
rb
.
u
n
it
E, eV
U
d
= 3.5 kV
P = 3*10
-5
Torr
1
Fig. 4. Ion energy distribution function at H = 1 kOe for different pressures discharge voltages and cathode type:
1 – check experiment; 2 – simulation experiment; 3 – MH-cathode; 4 – water-cooled MH-cathode
discharge voltages. Whereas desorbed hydrogen flow
depends on discharge current and for given cases the
flow was sufficiently lower than for simulation
experiment.
CONCLUSIONS
The possibility of discharge working only on the
hydrogen desorbed from MH-cathode due to ion-
stimulated processes is shown. The hydrogen desorption
does not sufficiently influence the discharge emissive
characteristics, which gives an opportunity to use the
data obtained in previous experiments.
The deciding factor for axial electron flow emission
is HF-instability developing under the conditions of
hydrogen being in non-equilibrium state desorption
from MH-cathode. Electron output only from one side is
caused by additional neutral hydrogen flow from a
cathode direction. After hydrogen desorbs from MH-
cathode completely, the third regime disappears, and
discharge behaves as in the case of usual cathodes.
REFERENCES
1. Yu.F. Shmal’ko, Ye.V. Klochko, N.V. Lototsky // Int.
J. Hydrogen energy. 1996, v. 21, p. 1057.
2. Ye.V. Klochko, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko // Probl. of Atomic Sci. and Tech. Series
“Plasma Electronics and New Acceleration methods”
(7). 2010, № 4, p. 226.
3. I.V. Borgun, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko // Problems of Atomic Sci. and Tech.
Series “Plasma Phys.”(83). 2013, № 1, p. 228.
4. Khauer W. Diocotron // J. Appl. Phys. 1966, v. 37,
№ 2, p. 602.
5. A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko // Problems of Atomic Sci. and Tech.
Series “Plasma Electronics and New Acceleration
Methods” (86). 2013, №4, p. 301.
Article received 24.10.2014
ВЛИЯНИЕ СПОСОБА НАПУСКА ВОДОРОДА НА ЭМИССИОННЫЕ ХАРАКТЕРИСТИКИ
РАЗРЯДА ПЕННИНГА С МЕТАЛЛОГИДРИДНЫМ КАТОДОМ
И.Н. Середа, А.Ф. Целуйко, Д.Л. Рябчиков, Е.В. Боргун, М.О. Гончаренко
Представлены результаты экспериментального исследования источника заряженных частиц
пеннинговского типа с металлогидридным катодом. С целью определения факторов, ответственных за
эмиссию отрицательных частиц в аксиальном направлении, изучено влияние разных способов напуска
водорода в ячейку. Для имитации десорбции применены катоды специальной конструкции и ион-
стимулированная десорбция водорода за счет принудительного охлаждения металлогидридного катода.
ВПЛИВ СПОСОБУ НАПУСКА ВОДНЮ НА ЕМІСІЙНІ ХАРАКТЕРИСТИКИ РОЗРЯДУ ПЕНІНГА
З МЕТАЛОГІДРИДНИМ КАТОДОМ
І.М. Середа, О.Ф. Целуйко, Д.Л. Рябчиков, Є.В. Боргун, М.О. Гончаренко
Представлено результати експериментального дослідження джерела заряджених частинок пенінговського
типу з металогідридним катодом. З метою визначення факторів, що відповідають за емісію негативних
частинок в аксіальному напрямку, вивчено вплив різних способів напуску водню в проміжок. Для імітації
десорбції застосовані катода спеціальної конструкції і іон-стимульована десорбція водню за рахунок
примусового охолодження металогідридного катоду.
|
| id | nasplib_isofts_kiev_ua-123456789-81941 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T17:27:18Z |
| publishDate | 2014 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Borgun, I.V. Goncharenko, M.O. 2015-05-22T17:38:50Z 2015-05-22T17:38:50Z 2014 Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode / I.N. Sereda, A.F. Tseluyko, D.L. Ryabchikov, I.V. Borgun, M.O. Goncharenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 201-203. — Бібліогр.: 5 назв. — англ. 1562-6016 PACS: 52.80.Sm https://nasplib.isofts.kiev.ua/handle/123456789/81941 The experimental studies of the Penning-type charged particle source with metal hydride cathode are presented. In order to determine the mechanisms responsible for the emission of negative particles in the axial direction, the influence of different hydrogen feeding methods were studied. To simulate hydrogen desorption the cathode of special design was applied and to force only hydrogen ion-stimulated desorption the forced cooling metal hydride cathode was used. Представлены результаты экспериментального исследования источника заряженных частиц пеннинговского типа с металлогидридным катодом. С целью определения факторов, ответственных за эмиссию отрицательных частиц в аксиальном направлении, изучено влияние разных способов напуска водорода в ячейку. Для имитации десорбции применены катоды специальной конструкции и ион-стимулированная десорбция водорода за счет принудительного охлаждения металлогидридного катода. Представлено результати експериментального дослідження джерела заряджених частинок пенінговського типу з металогідридним катодом. З метою визначення факторів, що відповідають за емісію негативних частинок в аксіальному напрямку, вивчено вплив різних способів напуску водню в проміжок. Для імітації десорбції застосовані катода спеціальної конструкції і іон-стимульована десорбція водню за рахунок примусового охолодження металогідридного катоду. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Низкотемпературная плазма и плазменные технологии Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode Влияние способа напуска водорода на эмиссионные характеристики разряда пеннинга с металлогидридным катодом Вплив способу напуска водню на емісійні характеристики розряду пенінга з металогідридним катодом Article published earlier |
| spellingShingle | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode Sereda, I.N. Tseluyko, A.F. Ryabchikov, D.L. Borgun, I.V. Goncharenko, M.O. Низкотемпературная плазма и плазменные технологии |
| title | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| title_alt | Влияние способа напуска водорода на эмиссионные характеристики разряда пеннинга с металлогидридным катодом Вплив способу напуска водню на емісійні характеристики розряду пенінга з металогідридним катодом |
| title_full | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| title_fullStr | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| title_full_unstemmed | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| title_short | Influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| title_sort | influence of hydrogen supply on emissive characteristics of pig with metal-hydride cathode |
| topic | Низкотемпературная плазма и плазменные технологии |
| topic_facet | Низкотемпературная плазма и плазменные технологии |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81941 |
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