Improvement of penning ion sources
It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to appearance of asymmetry of current magnitude to the cathodes of the Penning...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2000 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Цитувати: | Improvement of penning ion sources / A.A. Bizyukov, Vl.V. Bobkov, A.Y. Kashaba, K.N. Sereda // Вопросы атомной науки и техники. — 2000. — № 3. — С. 153-155. — Бібліогр.: 6 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860258068009320448 |
|---|---|
| author | Bizyukov, A.A. Bobkov, Vl.V. Kashaba, A.Y. Sereda, K.N. |
| author_facet | Bizyukov, A.A. Bobkov, Vl.V. Kashaba, A.Y. Sereda, K.N. |
| citation_txt | Improvement of penning ion sources / A.A. Bizyukov, Vl.V. Bobkov, A.Y. Kashaba, K.N. Sereda // Вопросы атомной науки и техники. — 2000. — № 3. — С. 153-155. — Бібліогр.: 6 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to appearance of asymmetry of current magnitude to the cathodes of the Penning cell, change of magnitude of current density and energy distribution of the ion beam extracted in a longitudinal direction. The use of an inhomogeneous magnetic field which is longitudinally asymmetrical concerning electrodes of the system allows to increase current efficiency of Penning ion sources from 0,2 to 0,55.
|
| first_indexed | 2025-12-07T18:51:33Z |
| format | Article |
| fulltext |
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 153-155 153
UDC 533.9
IMPROVEMENT OF PENNING ION SOURCES
A.A.Bizyukov, Vl.V.Bobkov, A.Y.Kashaba, K.N.Sereda
Kharkov National University, Faculty of physics and technologies, 31 Kurchatov Ave.,
Kharkov, 61108, Ukraine. E-mail: bizyukov@pht.univer.kharkov.ua
It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the
Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to ap-
pearance of asymmetry of current magnitude to the cathodes of the Penning cell, change of magnitude of current
density and energy distribution of the ion beam extracted in a longitudinal direction. The use of an inhomogeneous
magnetic field which is longitudinally asymmetrical concerning electrodes of the system allows to increase cur-
rent efficiency of Penning ion sources from 0,2 to 0,55.
INTRODUCTION
The ion sources on the basis of a gas discharge with
oscillating electrons (Penning discharge) and extrac-
tion of ions along a magnetic field are widely used due
to a low working pressure, high gas profitability, capa-
bilities of formation of ion beams with a large current
magnitude [1]. At the same time, the traditional design
of such discharge system, characterized by symmetry
electrical and magnetic fields concerning center of a
discharge system in longitudinal direction, results in a
symmetrical distribution of electric potential of plasma
with maximum value in center on each magnetic sur-
face. The ions are generated in volume of gas discharge
and are accelerated by a longitudinal electrical field to
cathodes of a Penning cell. With a symmetrical poten-
tial distribution the ion current from a plasma volume
also is uniformly distributed between cathodes of a
Penning cell. In ion sources with an oscillation of elec-
trons and longitudinal extraction only part of ions is
injected through a aperture in one of cathodes, that is
the cause of low current efficiency of such systems
which are not superior 0,1 [2].
One of probable ways of current efficiency increase
of ion sources on the basis of Penning discharge is the
formation of an asymmetrical longitudinal potential
distribution in plasma of a gas discharge and accelera-
tion of ions from a plasma volume predominantly in a
direction of the cathode-extractor of a beam. Such po-
tential distribution is possible to form with the help of
an inhomogeneous axial magnetic field, which, as
shown theoretically and experimentally in Ref. [3, 4],
allows to form and to support an electrical field in
plasma volume, irrelevant with influencing of elec-
trods.
EXPERIMENT DESCRIPTION
Experimental research of current efficiency of ion
source with Penning discharge with varied longitudinal
distribution of magnetic field were caryed out on the
device, wich is shown in fig. 1.
The ion source consists of a cylindrical tube, inside
which on insulators the electrodes of the Penning cell
are built-on. The anode of the Penning cell is a hollow
cylinder of length 28 mm and inner diamater of 19 mm
made from a stainless steel. At such sizes of an anode
the length-to-diameter ratio makes 1.5, that provides
optimum conditions for ionization in volume of gas
discharge with oscillating electrons [3]. The flat cath-
odes with diameter of 30 mm make from a stainless
steel were mounted symetricaly concerning anode on
the distance of 4 mm. The cathodes had axial apertures
with diameter of 2 mm, which were used for a injection
of an ion beam
Fig. 1. The scheme of the experimental device (1–
anode of the Penning cell; 2, 3– cathodes; 4– tube
meke from staneless steel; 5– ring-type permanent
magnet; 6– insulator; 7– electrical probe) and dis-
tribution of intesity of axial component of a magnetic
field on an axis of a system at three positions of a
magnet concerning an anode.
and input in a discharge gap of electrical probes. The
magnetic field formed by a ring-type constant magnet
by an altitude of 40 mm established is coaxial to an
anode on the ion source. In longitudinal direction mag-
154
net could displace concerning center of an anode of the
Penning cell on spacing interval of 20 mm. The distri-
bution of intensity of axial component of a magnetic
field on the axis of a system at three positions of a
magnet concerning an anode is shown also in fig. 1.
The ion source was established on the vacuum in-
stallation of a UVK-type and up to pressure 10-5 Torr
was evacuated. The positive potential by value 1–4 kV
fed on an anode (cathodes were grounded), that pro-
vided a stable combustion of discharge in the Penning
cell in pressure range Torr35 10105 −− ÷⋅ with usage as
working gases of argon, oxygen, azote.
In experiments voltage and discharge currents (on
an anode and cathodes) were measured. With the help
of the single Langmuir probe the potential of plasma on
an axis of a discharge system was measured. The cur-
rent of an ion beam leaving in a aperture of the cathode-
extractor was measured with the help of a Faraday cyl-
inder, and its energy distribution function – with the
help of a cylindrical energy analyzer.
DISCUSSION
The experiments demonstrate, that the disturbance
of a longitudinal symmetry of distribution of a mag-
netic field concerning center of a discharge system
produces change distribution of an electrostatic poten-
tial in a discharge gap, appearance asymmetry of value
of currents on cathodes of the Penning cell, change of
value of a current density and distribution function of
an ion beam leaving in longitudinal direction. In fig. 2
the relations of currents on cathodes of the Penning
cell and electrostatic potential on an axis of a discharge
system on a shear of an anode are shown depending on
displacement of center of magnetic system (coordinate
of maximum intensity of an axial component magnetic
field) from center of an anode of a discharge system. In
absence of displacement with a symmetrical distribu-
tion of a magnetic field concerning electrodes of a
discharge system the current is uniformly distributed
between cathodes. With disturbance of a symmetry the
discharge current is redistributed between cathodes,
being increased on the cathode, which is in a more gen-
tle magnetic field. Thus is proportional to a current on
the cathode-extractor the current of an ion beam
changes also. To increase of a beam current there cor-
responds reduction a magnetic field near the cathode-
extractor.
The electric potential changes proportionally to
magnetic field. With displacement of a magnet system
within the limits of ±5 mm concerning center, the cur-
rent on cathodes changes more than two times, and
electric potential on an axis of a discharge system
within the range of 20–30 %. The probe measurements
also demonstrate, that inside an anode of the Penning
cell there is asymmetrical concerning center of an an-
ode a distribution of electric potential.
In fig.3 the change of energy distribution function
of beam ions is shown depending on a position of a
magnetic system. The shape of a distribution function
indicates distribution of ionization speed in space of
the Penning cell, because the energy of ions in the
beam is determined by a potential of a point of ion
birth. With
displacement conforming to reduction of a magnetic
field near the cathode-extractor, from a shape of a dis-
tribution function it can be seen, that the increase of a
ion beam current and accordingly of current on the
cathode-extractor occurs as the expence of increase of
generating speed of ions in area with large spatial elec-
tric potentials inside an anode of a system. Change of a
distribution function of ions and the change of a poten-
tial distribution inside an anode at change of a magnetic
field allow to draw a conclusion, that an asymmetry of
currents on cathodes and concerned with it change of a
beam current are conditioned by change of value of a
plasma volume, from which the ions are accelerated on
the distant cathode. In longitudinal direction for each of
cathodes this volume is limited by a condition
max0 ϕϕ << where ö -the potential on the given mag-
netic surface. The appearance of an asymmetry of loca-
lization maxϕ concerning center of a discharge system
-6 -4 -2 0 2 4 6
30
40
50
60
70
80
φ
I
ñ2
I
ñ1
Z, mm
I ñ,
m
A
0
200
400
600
800
1000
φ, V
Fig. 2.
1,5 1,6 1,7 1,8 1,9 2,0
0,0
0,5
1,0
1,5
2,0
2,5
3
2
1
f,
a
.u
.
εε
i, keV
Fig. 3.
155
results in appearance of an asymmetry of ion fluxes on
cathodes and features of a energiy distribution function
of ions.
SUMMARY
Thus, the application of an inhomogeneous mag-
netic field, longitudinally asymmetrical concerning
electrods of a discharge system allows to increase cur-
rent efficiency of ion sources with the Penning dis-
charge. This method was applied at mining a multicellu-
lar ion source for etching and deposition of thin-film
coatings [6], that has allowed to increase its current
efficiency with 0.2 up to 0.55.
REFERENCES
[1] I. Braun, Physics and technology of ion sources,
M.: Mir, (1998), 496 p.
[2] Ì.D. Habovich, Physics and engineering of plasma
sources of ions, M.: Atomizdat, (1972), 304p.
[3] À.I. Morozov, Plasma accelerators and ion injec-
tors, M.: Nauka, (1984), 272 p.
[4] R.À. Demirhanov, Y.V. Kursanov, L.P. Skripal’,
G.V. Kharin, Obtaining of flows of energetic ions from
discharge with a high heat of electrons in an inhomoge-
neous magnetic field., Plasma accelerators, M.: Mashi-
nostroyeniye, (1973), 312 p.
[5] R.P. Babertsyan, E.S. Badalyan, G.À. Yegizaryan,
E.N. Ter-Gevorkyan, Mechanism of influencing of geo-
metrical parameter on the electrical characteristics
Penning ion source, Zh. Tech. Phys., (1998), v. 68, ¹ 9,
p 29.
[6] A.A. Bizyukov, A.Y. Kashaba, K.N. Sereda, A.Ph.
Tseluyko, N.N. Yunakov, Multichannel source of syn-
thesized ion-electrone flow, Rev. Sci. Instrum, (1996),
67 (12), p. 4117.
ACKNOWLEDGEMENT
This work was supported in the part by Science and
Technology Center in Ukraine, project #1112.
|
| id | nasplib_isofts_kiev_ua-123456789-82377 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T18:51:33Z |
| publishDate | 2000 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Bizyukov, A.A. Bobkov, Vl.V. Kashaba, A.Y. Sereda, K.N. 2015-05-29T07:36:42Z 2015-05-29T07:36:42Z 2000 Improvement of penning ion sources / A.A. Bizyukov, Vl.V. Bobkov, A.Y. Kashaba, K.N. Sereda // Вопросы атомной науки и техники. — 2000. — № 3. — С. 153-155. — Бібліогр.: 6 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/82377 533.9 It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to appearance of asymmetry of current magnitude to the cathodes of the Penning cell, change of magnitude of current density and energy distribution of the ion beam extracted in a longitudinal direction. The use of an inhomogeneous magnetic field which is longitudinally asymmetrical concerning electrodes of the system allows to increase current efficiency of Penning ion sources from 0,2 to 0,55. This work was supported in the part by Science and 
 Technology Center in Ukraine, project #111 en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Low Temperature Plasma and Plasma Technologies Improvement of penning ion sources Article published earlier |
| spellingShingle | Improvement of penning ion sources Bizyukov, A.A. Bobkov, Vl.V. Kashaba, A.Y. Sereda, K.N. Low Temperature Plasma and Plasma Technologies |
| title | Improvement of penning ion sources |
| title_full | Improvement of penning ion sources |
| title_fullStr | Improvement of penning ion sources |
| title_full_unstemmed | Improvement of penning ion sources |
| title_short | Improvement of penning ion sources |
| title_sort | improvement of penning ion sources |
| topic | Low Temperature Plasma and Plasma Technologies |
| topic_facet | Low Temperature Plasma and Plasma Technologies |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/82377 |
| work_keys_str_mv | AT bizyukovaa improvementofpenningionsources AT bobkovvlv improvementofpenningionsources AT kashabaay improvementofpenningionsources AT seredakn improvementofpenningionsources |