Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen
The results of experimental investigation of penning type charged particles source with metal-hydride watercooled cathode are presented. The feature of investigation is hydrogen ion-stimulated desorbtion from metal-hydride as a way of working gas feeding. The influence of ion-stimulated desorbtion o...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2013
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| Цитувати: | Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen / A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda, A.F. Tseluyko // Вопросы атомной науки и техники. — 2013. — № 4. — С. 301-303. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-1121542017-01-18T03:03:55Z Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen Agarkov, A.V. Ryabchikov, D.L. Sereda, I.N. Tseluyko, A.F. Приложения и технологии The results of experimental investigation of penning type charged particles source with metal-hydride watercooled cathode are presented. The feature of investigation is hydrogen ion-stimulated desorbtion from metal-hydride as a way of working gas feeding. The influence of ion-stimulated desorbtion on emissive source characteristics was studied. In outflowing in axial direction charged particles flow the dynamic of energy distribution function of electrons and ions was carried out and their dependence on discharge external parameters was determined. Представлено результати експериментального дослідження джерела заряджених частинок пенінговського типу з металогідридним катодом, що охолоджується. Особливість дослідження полягає в способі напуску робочого газу за рахунок іон-стимульованої десорбції водню з металогідриду. Вивчено вплив іонстимульованої десорбції на емісійні характеристики джерела. У вихідному із джерела в аксіальному напрямку потоці заряджених часток досліджена динаміка функцій розподілу іонів й електронів по енергіях і визначена їхня залежність від зовнішніх параметрів розряду. Представлены результаты экспериментального исследования источника заряженных частиц пеннинговского типа с металлогидридным водоохлажденным катодом. Особенность исследования заключается в способе напуска рабочего газа за счет ион-стимулированной десорбции водорода из металлогидрида. Изучено влияние ион-стимулированной десорбции на эмиссионные характеристики источника. В выходящем из источника в аксиальном направлении потоке заряженных частиц исследована динамика функций распределения ионов и электронов по энергиям и определена их зависимость от внешних параметров разряда. 2013 Article Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen / A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda, A.F. Tseluyko // Вопросы атомной науки и техники. — 2013. — № 4. — С. 301-303. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 52.80.Sm http://dspace.nbuv.gov.ua/handle/123456789/112154 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Приложения и технологии Приложения и технологии |
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Приложения и технологии Приложения и технологии Agarkov, A.V. Ryabchikov, D.L. Sereda, I.N. Tseluyko, A.F. Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen Вопросы атомной науки и техники |
| description |
The results of experimental investigation of penning type charged particles source with metal-hydride watercooled cathode are presented. The feature of investigation is hydrogen ion-stimulated desorbtion from metal-hydride as a way of working gas feeding. The influence of ion-stimulated desorbtion on emissive source characteristics was studied. In outflowing in axial direction charged particles flow the dynamic of energy distribution function of electrons and ions was carried out and their dependence on discharge external parameters was determined. |
| format |
Article |
| author |
Agarkov, A.V. Ryabchikov, D.L. Sereda, I.N. Tseluyko, A.F. |
| author_facet |
Agarkov, A.V. Ryabchikov, D.L. Sereda, I.N. Tseluyko, A.F. |
| author_sort |
Agarkov, A.V. |
| title |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| title_short |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| title_full |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| title_fullStr |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| title_full_unstemmed |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| title_sort |
pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2013 |
| topic_facet |
Приложения и технологии |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/112154 |
| citation_txt |
Pig with metal-hydride cathode under ion-stimulated desorbtion of hydrogen / A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda, A.F. Tseluyko // Вопросы атомной науки и техники. — 2013. — № 4. — С. 301-303. — Бібліогр.: 4 назв. — англ. |
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Вопросы атомной науки и техники |
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2025-07-08T03:28:23Z |
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| fulltext |
ISSN 1562-6016. ВАНТ. 2013. №4(86) 301
PIG WITH METAL-HYDRIDE CATHODE UNDER ION-STIMULATED
DESORBTION OF HYDROGEN
A.V. Agarkov, D.L. Ryabchikov, I.N. Sereda, A.F. Tseluyko
V.N. Karazin Kharkov National University, Kharkov, Ukraine
E-mail: igorsereda@mail.ru
The results of experimental investigation of penning type charged particles source with metal-hydride water-
cooled cathode are presented. The feature of investigation is hydrogen ion-stimulated desorbtion from metal-hydride
as a way of working gas feeding. The influence of ion-stimulated desorbtion on emissive source characteristics was
studied. In outflowing in axial direction charged particles flow the dynamic of energy distribution function of elec-
trons and ions was carried out and their dependence on discharge external parameters was determined.
PACS: 52.80.Sm
INTRODUCTION
Metal-hydride cathode (MH-cathode) applying in
plasma sources of charged particles is of interest for
modern science. Desorbed from the cathode hydrogen
due to exposure to heat is in activated state and has the
ionization potential on 0.5 eV lower and ionization
cross-section in 1.5 times higher than common molecu-
lar balloon hydrogen [1]. This is sufficiently raising the
efficiency of an ion source. The complementary advan-
tages of MH-cathode using are compactness and safety
of hydrogen store as well as possibility to realize the
local gas feeding. But for all that MH-cathode using
leads to discharges parameters and characteristics of
outflowing charged particles flow changing [2]. It con-
cerned with state changing of feeding hydrogen [3].
The problem in creation of working source is strong
dependence of desorbed hydrogen flow on MH-cathode
temperature that makes difficult to stabilize the dis-
charge regime. For solving this problem the authors
offer to apply forced water-cooling of MH-cathode. In
this case maintaining temperature of MH-cathode lower
than hydride phase decomposition one, the hydrogen
desorbtion should be realized due to ion-stimulated
processes and desorbtion velocity should be determined
only by ion current bombardment of metal-hydride sur-
face.
1. EXPERIMENTAL SETUP
The experimental investigations were carried out in
discharge cell of penning configuration set in longitudi-
nal magnetic field (Fig. 1). The cylindrical anode was
3.7 cm in diameter and 3 cm in length. MH-cathode (2)
was a disk 2 cm in diameter and 0.5 cm in thick. It was
pressed from powder mixture of saturated with hydro-
gen Zr50V50Hx alloy and copper stuff. The initial satura-
tion of MH-cathode with hydrogen was about 900 cm3
at normal conditions
MH-cathode was placed in copper cathode-
holder (3) 2.5 cm in diameter, which has water-cooling.
For ensuring a good heat contact of MH-cathode with
cathode-holder its surface was covered with heat-
conducting spread. The MH-cathode temperature was
controlled by thermocouple (4). The copper cathode-
reflector (5) 2 cm in diameter and 0.5 cm in thick has a
hole at the center 0.5 cm in diameter. Behind the hole
the collector (6) for outflow charged particles current
measurement was set. At energy spectra investigation
by the method of retarding field the collector was
changed on 4th electrode electrostatic energy-analyzer.
On the first grid the tearing potential +3 kV or -0.2 kV
for separation of electron or ion part in outflow current
correspondingly was supplied. The distance between
anode and cathodes was 1 cm. In check experiments
MH-cathode was changed with copper one of same
form and dimensions.
The whole electrode system was fixed inside the
quartz cylinder played a role of electrostatic shield.
Fig. 1. The scheme of discharge cell: 1 – anode;
2 – MH-cathode; 3 – cathode-holder; 4 – thermocouple;
5 – cathode-reflector; 6 – collector
The residual pressure in vacuum chamber not ex-
ceeds 3⋅10-6 Torr. The investigations were carried out at
the pressure of 10–6…10–4 Torr.
2. RESULTS AND DISCUSSION
The forced MH-cathode cooling is shown to stabi-
lize the discharge working pressure and eliminates hy-
drogen kick due to uncontrolled thermal decomposition
of hydride phases. Low temperature of MH-cathode
(lower than hydride phases decomposition one) ensures
hydrogen desporbtion only by ion-stimulated processes.
It gives the possibility to operate the hydrogen de-
sorbtion velocity by current discharge. At that hydrogen
consumption sufficiently reduces and time of the source
continuous work raises.
Fig. 2 shows typical dependences of pressure (a),
discharge current (b) and collector current (c) on dis-
charge voltage. The discharge was ignited on residual
pressure P = 5·10-6 Torr. There is no external gas supply
so the pressure change during the discharges working
could be unambiguously joined with hydrogen de-
sorbtion from MH-cathode.
One can see that in case of two copper cathodes the
pressure changes weakly (dotted line on Fig. 2,a). At the
same time in case of MH-cathode (solid line) starting
from discharge voltage Ud ≈ 2 kV (it corresponds to
discharge current Id ≈ 0.2 mA (see Fig. 2,b) the pressure
rises due to hydrogen desorbtion under ion-stimulated
1
2
3
4
water
56
ISSN 1562-6016. ВАНТ. 2013. №4(86) 302
processes. Increasing Id up to 1 mA leads to working
pressure set up on the level of 2·10-5 Torr.
0 1 2 3 4 5
4
6
8
10
12
14
16
P*
10
-6
T
or
Ud, kV
a
0 1 2 3 4 5
0,0
0,5
1,0
1,5
1'
2'
2I d,
m
A
Ud, kV
1
b
0 1 2 3 4 5
-80
-60
-40
-20
0
20 2'
2
1'I c, μ
A Ud, kV
1
c
Fig. 2. Dependences of pressure (a), discharge current
(b) and collector current (c) on discharge voltage at
initial pressure P = 5·10-6 Torr.
Dotted line corresponds to check discharge,
solid line – discharge with MH-cathode.
1 – MH-cathode, Н = 600 Э; 1’ – check discharge;
2 – MH-cathode, Н = 1000 Э; 2’ – check discharge
It is important that the pressure in vacuum chamber
is determined by discharge current and at changing it in
one or another side the pressure rapidly changes and
stabilizes on the new level.
The current-voltage characteristics presented in
Fig. 2,b are show to require heightened voltage drop in
case of discharge with MH-cathode as compared with
check one. The reason is repeatedly discussed, for in-
stance in [4], and obviously concerned with dissociative
capture of slow electrons by vibrationaly excited mole-
cules of desorbed hydrogen.
There are differences in outflowing from discharge
flows of charged particles (see Fig. 2,c) as well. At high
magnetic field the discharge with MH-cathode works at
three-regimes (curve 2). The first one is characterized
by axial electron yield (Ud ≈ 1…2.3 kV), the second one
– by ion yield (Ud > 2.4 kV) and the third one – again
by electron yield (Ud > 3.5 kV). Such a behavior was
typical in the range of magnetic field changing from 700
up to 1000 Oe. These regimes are in detail described in
[2, 3] and concerned with oscillation processes in anode
layer. There is no 3rd regime when using both copper
cathodes (curve 2’).
At low magnetic fields about 500…600 Oe both in
case of MH-cathode and in check experiments the col-
lector was registered only negative current value (see
curves 1 and 1’ in Fig. 2,b). The collector current in
discharge with MH-cathode is about in two times bigger
than in check one that obviously due to transition of the
first regime straight away to the third one. The check
discharge keep works in the first regime (curve 1’). It
should be pointed out that such a behavior in the check
discharge was only at residual pressure working. At
even minor balloon hydrogen feeding the collector cur-
rent turned in to positive values already at Ud > 2 kV:
the discharge transits to the second regime.
In the other side the discharge with MH-cathode
transited to three-regime working only as from the pres-
sure of 3·10-5 Тorr (Fig. 3). But for all that balloon hy-
drogen was feed for working pressure set up. (In our
case the only hydrogen desorbtion due to ion-stimulated
processes was not enough).
0 1 2 3 4 5
-100
-80
-60
-40
-20
0
20
I c,
μA Ud, kV
12
3
4
Fig. 3. The dependence of collector current
on discharge voltage at Н = 600 Oe for different
pressures. 1 – P = 5·10-6 Torr; 2 – P = 2·10-5 Torr;
3 – P = 3·10-5 Torr; 4 – P = 5·10-5 Torr
Such a behavior was typical either at pressure or at
magnetic field rising. It is agreed with results carried out
in [2]. At magnetic field lower than 500 Oe the dis-
charge works only in second regime (with ions yield in
axial direction) in whole investigated range of pressure.
The analysis of energy spectra of outflowing
charged particles flow revealed a number of peculiari-
ties as well. At working on residual pressure electrons
have weak dependence of energy both on discharge
voltage and magnetic field. The most likely electron
energy there is about 20 eV (Fig. 4,a), and the main part
of electrons posses energy in the range from 10 to
75 eV.
Increasing of initial pressure due to external balloon
hydrogen feeding leads to widening of electron energy
distribution function and maxima shifting in direction of
bigger energy values (Fig. 4,b). It is important to note
the fact is most pronounced at the pressure of
P = 3·10-5 Torr, which corresponds to discharge transi-
tion in to three-regime working (see curve 3 in Fig. 3)
and concerned with extra energy getting of electrons
against an intensive oscillation development in the dis-
charge [3]. The same dependence of distribution func-
tion is registered at more high values of magnetic field.
The reversed situation is observed at ion component
in outflowing axial flow investigation. Magnetic field
increasing leads to significant rising of ion energy
(Fig. 5). If at Н = 600 Oe ion energy was about 8% from
discharge voltage then at Н > 700 Oe – about 50% with
tendency to saturation at discharge voltage drop rising.
At heightened values of magnetic field or initial
pressures in chamber the average ion energy has a weak
dependence on these parameters.
ISSN 1562-6016. ВАНТ. 2013. №4(86) 303
0 10 20 30 40 50 60 70
0,0
0,1
0,2
0,3
0,4
0,5
0,6
a
H = 1000 Oe
H = 800 Oe
H = 600 Oe
E, eV
arb. units
0 20 40 60 80 100 120 140 160 180
0,0
0,1
0,2
0,3
0,4
b
P = 3*10-5 Tor
P = 1*10-5 Tor
P = 5*10-6 Tor
E, eV
arb. units
Fig. 4. Electron energy distribution function at
Ud = 4.5 kV for constant pressure P = 5·10-6 Torr (a)
and for constant magnetic field Н = 600 Oe (b)
0 500 1000 1500 2000 2500 3000
0,000
0,002
0,004
0,006
H = 1000 Oe
H = 800 Oe
arb. units
E, eV
H = 600 Oe
Fig. 5. Ion energy distribution function at Ud = 4.5 kV
for initial pressure P = 5·10-6 Torr
Thus, in the range of external parameters described
with curves 1 and 2 in Fig. 3 (P < 3·10-5 Torr,
H ≈ 500…600 Oe), when the second regime of dis-
charge working is absent, the average energy of ions
outflew along the axis is small. The electron energy
possesses a minimal value as well. In this case ioniza-
tion of desorbed hydrogen with oscillated along the axis
electrons occurs mainly by the axis where the space
potential is small. The discharge transition to the three-
regime working causes by instability development in
anode layer [2, 3]. Electron energy at that rises, and the
area of main ionization shifts from the axis in to anode
layer. And last but not the least, forced water cooling of
MH-cathode is shown to stabilize the discharge working
pressure and provides hydrogen desorbtion only by ion-
stimulated processes.
REFERENCES
1. Yu.F. Shmal’ko, Ye.V. Klochko, N.V. Lototsky.
Influence of isotopic effect on the shift of the ioniza-
tion potential of hydrogen desorbed from metal hy-
dride surface // Int. J. Hydrogen energy. 1996, v. 21,
p. 1057-1059.
2. Ye.V. Klochko, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko. Influence of metal-hydride cathode
on electron yield from PIG // Probl. of Atomic Sci.
and Tech. Series “Plasma Electronics and New Ac-
celeration Methods” (7). 2010, № 4, p. 226-229 (in
Russian).
3. I.V. Borgun, D.L. Ryabchikov, I.N. Sereda,
A.F. Tseluyko. Experimental simulation of metal-
hydride cathode working in Penning discharge //
Probl. of Atomic Sci. and Tech. Series “Plasma
Physics” (83). 2013, № 1, p. 228-230.
4. V.N. Borisko, Ye.V. Klochko, I.N. Sereda. Influence
of saturation degree of metal-hydride cathode on
characteristics of Penning type ion source of hydro-
gen // Probl. of Atomic Sci. and Tech. Series
“Plasma Physics”(3). 2003, № 3, p. 217-220.
Article received 13.03.2013.
РАЗРЯД ПЕННИНГА С МЕТАЛЛОГИДРИДНЫМ КАТОДОМ ПРИ ИОН-СТИМУЛИРОВАННОЙ
ДЕСОРБЦИИ ВОДОРОДА
А.В. Агарков, Д.Л. Рябчиков, И.Н. Середа, А.Ф. Целуйко
Представлены результаты экспериментального исследования источника заряженных частиц пеннингов-
ского типа с металлогидридным водоохлажденным катодом. Особенность исследования заключается в спо-
собе напуска рабочего газа за счет ион-стимулированной десорбции водорода из металлогидрида. Изучено
влияние ион-стимулированной десорбции на эмиссионные характеристики источника. В выходящем из ис-
точника в аксиальном направлении потоке заряженных частиц исследована динамика функций распределе-
ния ионов и электронов по энергиям и определена их зависимость от внешних параметров разряда.
РОЗРЯД ПЕНІНГУ З МЕТАЛОГІДРИДНИМ КАТОДОМ ПРИ ІОН-СТИМУЛЬОВАНІЙ
ДЕСОРБЦІЇ ВОДНЮ
А.В. Агарков, Д.Л. Рябчиков, І.М. Середа, О.Ф. Целуйко
Представлено результати експериментального дослідження джерела заряджених частинок пенінговсько-
го типу з металогідридним катодом, що охолоджується. Особливість дослідження полягає в способі напуску
робочого газу за рахунок іон-стимульованої десорбції водню з металогідриду. Вивчено вплив іон-
стимульованої десорбції на емісійні характеристики джерела. У вихідному із джерела в аксіальному напря-
мку потоці заряджених часток досліджена динаміка функцій розподілу іонів й електронів по енергіях і ви-
значена їхня залежність від зовнішніх параметрів розряду.
Torr
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