Plasma lens for MeV heavy ion beam focusing
The investigations of heavy ion beam focusing and governing that were carried out at the accelerator of heavy ions «UTI-1». are represented. The focusing of continuous ion beam of Mo⁺⁴ (0.9 MeV, 25 mA) by plasma lens (PL) was investigated. PL was produced by ion beam itself due to ionization process...
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| Date: | 2000 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Cite this: | Plasma lens for MeV heavy ion beam focusing / B.P. Il’enko, I.M. Nekludov, I.N. Onishchenko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 123-124. — Бібліогр.: 8 назв. — англ. |
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Il’enko, B.P. Nekludov, I.M. Onishchenko, I.N. 2015-05-29T08:37:41Z 2015-05-29T08:37:41Z 2000 Plasma lens for MeV heavy ion beam focusing / B.P. Il’enko, I.M. Nekludov, I.N. Onishchenko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 123-124. — Бібліогр.: 8 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/82394 533.9 The investigations of heavy ion beam focusing and governing that were carried out at the accelerator of heavy ions «UTI-1». are represented. The focusing of continuous ion beam of Mo⁺⁴ (0.9 MeV, 25 mA) by plasma lens (PL) was investigated. PL was produced by ion beam itself due to ionization processes at hydrogen leak-in (0.5— 1 cm³/min) and confinement of electrons by applyed magnetic field of intensity 0.8 kOe. Beam focusing was estimated from measuring of beam diameter decreasing and corresponding current density increasing. This work was partly supported by STCU (Project No. 298). en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Вeams in Plasma Plasma lens for MeV heavy ion beam focusing Article published earlier |
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Plasma lens for MeV heavy ion beam focusing |
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Plasma lens for MeV heavy ion beam focusing Il’enko, B.P. Nekludov, I.M. Onishchenko, I.N. Вeams in Plasma |
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Plasma lens for MeV heavy ion beam focusing |
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Plasma lens for MeV heavy ion beam focusing |
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Plasma lens for MeV heavy ion beam focusing |
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Plasma lens for MeV heavy ion beam focusing |
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plasma lens for mev heavy ion beam focusing |
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Il’enko, B.P. Nekludov, I.M. Onishchenko, I.N. |
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Il’enko, B.P. Nekludov, I.M. Onishchenko, I.N. |
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Вeams in Plasma |
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Вeams in Plasma |
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2000 |
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Вопросы атомной науки и техники |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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The investigations of heavy ion beam focusing and governing that were carried out at the accelerator of heavy ions «UTI-1». are represented. The focusing of continuous ion beam of Mo⁺⁴ (0.9 MeV, 25 mA) by plasma lens (PL) was investigated. PL was produced by ion beam itself due to ionization processes at hydrogen leak-in (0.5— 1 cm³/min) and confinement of electrons by applyed magnetic field of intensity 0.8 kOe. Beam focusing was estimated from measuring of beam diameter decreasing and corresponding current density increasing.
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1562-6016 |
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https://nasplib.isofts.kiev.ua/handle/123456789/82394 |
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Plasma lens for MeV heavy ion beam focusing / B.P. Il’enko, I.M. Nekludov, I.N. Onishchenko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 123-124. — Бібліогр.: 8 назв. — англ. |
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AT ilenkobp plasmalensformevheavyionbeamfocusing AT nekludovim plasmalensformevheavyionbeamfocusing AT onishchenkoin plasmalensformevheavyionbeamfocusing |
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2025-11-25T21:34:04Z |
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2025-11-25T21:34:04Z |
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1850553478252855296 |
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Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 123-124 123
UDC 533.9
PLASMA LENS
FOR MEV HEAVY ION BEAM FOCUSING
B.P.Il’enko, I.M.Nekludov, I.N.Onishchenko
National Science Center “Kharkov Institute of Physics & Technology”
Academic St. 1, Kharkov, 61108, Ukraine
E-mail: onish@kipt.kharkov.ua
The investigations of heavy ion beam focusing and governing that were carried out at the accelerator of heavy
ions «UTI-1». are represented. The focusing of continuous ion beam of Mo+4 (0.9 MeV, 25 µA) by plasma lens
(PL) was investigated. PL was produced by ion beam itself due to ionization processes at hydrogen leak-in (0.5—
1cm3/min) and confinement of electrons by applyed magnetic field of intensity 0.8 kOe. Beam focusing was
estimated from measuring of beam diameter decreasing and corresponding current density increasing.
1. INTRODUCTION
For deep implantation technology and material
modification the ion beams of metals and gases of
more high energy are needed than in known ion sources
with plasma lens using [1-6]. The application of
plasma/electron cloud for focusing and governing of
ion beams has been started from Gabor proposal [1],
later in the development of Morozov’s plasma optics
[2] and has been widely investigated by Goncharov et al
[3] both theoretically and experimentally. The attempts
to apply such type of plasma lens for focusing of high-
energy ion beam have been undertaken by Lefevre [4]
for nuclear microprobe and Onishchenko et al [5,6] for
intense proton beam of 5 Mev energy.
In NSC KIPT the source of multicharged heavy ions
was created and electrostatic accelerator was put into
operation to obtain ions of MeV-range energy [7]. By
means of 2 quadrupolar lens initially strip beam of
Mo+4 with cross-section 5 cm × 0.4 cm was
transformed into cylindrical beam of diameter 2 cm. .
In this report the experimental investigations are
represented on plasma lens using for focusing and
governing of heavy and multicharged ions of high
energy. The necessity of such ion beams manipulating
is caused by its application in semiconductors
technologies [8], surface hardening, radiation damage
simulation, etc. In Sec. 2 the experimental setup is
described. Sec 3 represents the results of continuous
ion beam of Mo+4 (0.9 MeV, 25 µA) focusing by
plasma lens that was produced at hydrogen leak-in
(0.5—1 cm3/min) and applying magnetic field of
intensity 0.8 kOe. Beam focusing was evaluated from
measuring of beam diameter decreasing (2 times) and
corresponding current density increasing. In the last
Sec. 4 the experimental results are summarized.
2. EXPERIMENTAL SETUP
The investigation of heavy ion beam focusing was
carried out at the accelerator of heavy ions «UTI-1».
This accelerator (Fig.1) consists of the following units:
the ion source of metals and gases (1,2), Vacuum
chamber of mass-analyzer (3), mass-analyzer (4), the
system of beam governing (7), quadrypolar lenses(8),
accelerating system (10), system of ion beam focusing
(13), target complex(17). The ion source that is used in
the accelerator produces strip beam (5 cm × 0.4 cm) of
multicharged ion s of various metals and gases. The
quadrupolar lens was used to form cylindrical ion beam
of diameter 2 cm from strip one. The accelerating
process has two stages - firstly to the energy E1 = ΖU1
in ion optic system , and secondary in accelerating tube
to the energy E2 = ΖU2, where U1 and U2 are the
accelerating voltages of ion source and accelerating
tube, correspondingly, Ζ is ion charge. The total energy
of accelerated ion is E = Ζ(U1 +U2). Magnetic
separation was performed at low ion energy (U1 = 25 -
125 kV). The accelerating tube voltage was U2 = 200
eV. In particular the maximum energy of Mo4+ reaches
0,9 ÌeV, and current 25 µA.
Fig. 1. Experimental installation. 1, 2 - ion sours of
metals and gases, accordingly , 3 - vacuum chamber
of mass analyzer, 4 mass - analyzer , 5 - system for
vacuum measuring, 6 - unit for beam current
measuring, 7 - system of beam declining, 8 -
quadrupolar lens, 9, 11 - silphones, 10 - accelerating
system, 12 - magnetic field coil, 13 - PL chamber, 14 -
insulator, 15 - rectifier on 200 kV. 16, 19 - vacuum
valve, 17 - target complex, 18 - vacuum chamber, 20 -
magnetic discharged pump.
124
The hydrogen leak-in was regulated by the pin value.
The gas amount was chosen so (0.5-2 cm3 /min) that
the beam current had a maximum value.
3. EXPERIMENTAL RESULTS
During ion beam propagation through the hydrogen
the gas ionization and plasma production takes place. In
magnetic field (0-0.8 kOe) plasma ions are
nonmagnetized and they leave the system. At the same
time plasma electrons are confined in magnetic field
and create plasma lens as an electron cloud
(noncompensated plasma). Its electric field is focusing
one for ion beam.
At hydrogen leak-in 1cm3 /min and more, and for
Ìî4+ ion energy less 350 keV the current decreasing in
several times and changing of charge state and energy
spectrum were observed. It can be explained by
recombination and charge exchange processes of
multicharged Mo ions on hydrogen atoms.
At ion energy growth to 1 MeV and gas leak-in of 0.5-1
cm3 /min the capture cross-section decreases
considerably and the probability of charge exchange
falls down. Under these conditions the ion beam
current increasing and its transversal size lessening was
oserved.
For this case the changing of the beam crossection
shape was measured on the beam imprint at the
collector of diameter 3 cm, that was placed at distance
30 cm from plasma lens and 45 cm from accelerator
exit.
The dependence of the beam cross-section
lessening on the magnetic field value is represented in
Fig.2. It is seen that in process of beam focusing by
electron cloud its diameter decreases with magnetic
field growth and for 0,8 kOe it is 0,8 cm.
0
0,4
0,8
1,2
1,6
2
0 0,5 1
H , kOe
D , sm
Fig. 2. The dependence of Mo+4 beam diameter on
magnetic field value.
Simultaneously with beam cross-section
measurements the beam current density were measured
by Faraday microcup with inner diameter 3 mm. In
Fig.3 the dependence of the beam current on this
microcup on magnetic field value is shown. During
focusing the beam current grows in 2 times. It is
additional evidence of focusing process. However
incomplete correspondence of these two
measurements is probably connected with considerable
decreasing of the total beam current under beam charge
exchange on gas target. On this reason in further
investigations it is proposed to create electron cloud by
means of electrons injection into magnetic trap instead
of gas ionization.
0
0,5
1
1,5
2
2,5
0 0,5 1
H , kOe
I ,
mkA
Fig. 3. The dependence of Mo+4 beam current density
on magnetic field value
4. SUMMARY
Therefore the experimental investigations have
shown that multicharged heavy ions of metals can be
focused by plasma lens which is created during ion
beam propagation in hydrogen gas with magnetic field
applying for electrons confinement.
This work was partly supported by STCU (Project
No. 298).
REFERENCES
1. D. Gabor // Nature (London), 1947, v. 160, p. 89.
2. A. Morozov // Doklady Akad. Nauk SSSR, 1965, v.
36, p. 1363
3. A. Goncharov, // Rev. Sci. Instrum.. 1998, v. 69, ¹
2, p. 150.
4. H.Lefevre, //Nucl. Instrum.Methods Phys. Res. B,
1985, ¹ 10/11, p.707.
5. V.N. Belan, V.I. Butenko, B.I. Ivanov, V.A.Kiselev,
A.F.Linnik, I.N.Onishchenko, V.P.Prishchepov, and
A.M.Yegorov //.Rev. Sci. Instrum.. 1998, v. 69, ¹
2, p. 1110.
6. STCU Project ¹ 298 // Plasma Lens for Focusing
of Ion Beams, 1996-1998
7. B.P. Il’enko, I.M. Nekludov, and I.N. Onishchenko
// Rev. Sci. Instrum.. 1998, v. 69, ¹ 2, p. 849.
8. T.N. Horski // 7th Int.Conf. on Ion Sources,
Taormina, Italy, Sept. 7-13, 1997. O-D.01 p. 78
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