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Feb 2000

Volume 71, Issue 2, pp. 335-1239

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Electron energy distribution function in a Hall-type thruster (abstract)

M. Bacal, V. Yu. Fedotov, G. Guerrini, A. A. Ivanov, and A. N. Vesselovzorov

Rev. Sci. Instrum. 71, 731 (2000); http://dx.doi.org/10.1063/1.1150276 (1 page)

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The electron energy distribution function measured at the channel exit of a small Hall-type thruster is interpreted as a beam-plasma electron distribution function with electron beam energy of several tens of electron volts. Although unstable, the distribution function does not correspond to the completely quasilinear relaxed beam function. Comparison with the measured function in the vicinity of the channel exit shows that the electron beam energy is about 30 eV for the total voltage applied ≅200 V. The contribution of the electron beam is shown to be essential in the ionization of the working gas, even when single ionization processes only are considered. © 2000 American Institute of Physics.
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52.75.Di Ion and plasma propulsion
89.40.-a Transportation

Broad-beam modeling and experiments for electric spacecraft propulsion

M. Tartz, E. Hartmann, R. Deltschew, and H. Neumann

Rev. Sci. Instrum. 71, 732 (2000); http://dx.doi.org/10.1063/1.1150277 (3 pages) | Cited 2 times

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At IOM Leipzig, we developed an efficient grid erosion simulation code. In our approach to ion beam extraction and grid erosion occurring in a multi-grid multi-aperture ion thruster we break down the complex interplay of pertinent elementary processes into consecutive steps. On the basis of ion optical and short-time grid-erosion measurements on a small broad-beam ion source, a comprehensive experimental validation of this code has been done. The good agreement between measured and simulated data furnishes confidence in the methodology. © 2000 American Institute of Physics.
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89.40.-a Transportation
95.55.Pe Lunar, planetary, and deep-space probes
07.77.Ka Charged-particle beam sources and detectors
41.85.Ar Particle beam extraction, beam injection

Magnetic field profile dependence of zirconium flux in sputtering ion sources

T. Suzuki, Y. Kawai, T. Saburi, Y. Fujii, and N. Kitayama

Rev. Sci. Instrum. 71, 735 (2000); http://dx.doi.org/10.1063/1.1150278 (3 pages) | Cited 2 times

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A zirconium sputtering ion source was studied. The argon plasma discharged by electron cyclotron resonance was used as the sputtering working plasma. A cylindrical-type target was used as the sputter target. The zirconium flux is evaluated at the downstream side of the ion source by varying the magnetic field profile of the ion source. And a magnetic profile dependence of the zirconium flux was observed. Zirconium ions and argon ions were detected by a quadrupole mass spectrometer. From the zirconium flux and the ion current, the ionization efficiency was evaluated. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
52.50.Gj Plasma heating by particle beams
28.60.+s Isotope separation and enrichment

Steady state operation of an ampere-class hydrogen negative ion source

Naoki Miyamoto, Yukio Fujiwara, Kenji Miyamoto, and Yoshikazu Okumura

Rev. Sci. Instrum. 71, 738 (2000); http://dx.doi.org/10.1063/1.1150279 (3 pages) | Cited 6 times

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A cesium-seeded volume negative ion source producing H− ion beams of 800 mA has been operated continuously at a high current density of 20 mA/cm2. The ion source consists of a magnetically filtered multicusp plasma generator and a multiaperture extractor. The ion source has a frame-cooling-type plasma grid, which is continuously able to keep the temperature at optimum using radiation from filaments and arc discharge. The ion source produces about 150 mA of H− in operation without cesium (pure volume operation). The negative ion yield is enhanced by more than a factor of four by injecting 600 mg of cesium. It is important to keep the plasma grid surface temperature at about 300 °C, where the negative ion yield has the maximum. The plasma generator has six tungsten filament cathodes of 1.2 mm in diameter. To estimate a lifetime of the filaments, weight and diameter of the filaments were measured after continuous operation. It was found that evaporation is the dominant wearing-out process, and no significant sputtering effect such as the self-sputtering, cesium sputtering, and chemical sputtering was observed. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors

Recovery of cesium in the hydrogen negative ion sources

Yu. I. Belchenko, Y. Oka, O. Kaneko, Y. Takeiri, A. S. Krivenko, M. Osakabe, K. Tsumori, E. Asano, T. Kawamoto, and R. Akiyama

Rev. Sci. Instrum. 71, 741 (2000); http://dx.doi.org/10.1063/1.1150280 (3 pages) | Cited 6 times

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Cesium recovery from the polluted layers in the 1/3 scale hydrogen negative ion source for LHD-NBI system has tested. It was found that the cesium recovery can be produced by additional discharges as from the cesium layer, aged by tungsten and residual gas, so as from the cesium layers, polluted by an occasional water leak. The highest cesium recovery to negative ion production was produced by a xenon arc, while glow discharge and arcing in hydrogen were less effective. The mechanism of recovery is the ejection of cesium from the underlying enriched layer by the arc and its transport to the surface. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
52.80.Hc Glow; corona

Neutral beams for the International Thermonuclear Experimental Reactor

T. Inoue, E. Di Pietro, P. L. Mondino, P. Bayetti, R. S. Hemsworth, P. Massmann, Y. Fujiwara, M. Hanada, K. Miyamoto, Y. Okumura, K. Watanabe, A. Krylov, V. Kulygin, and A. Panasenkov

Rev. Sci. Instrum. 71, 744 (2000); http://dx.doi.org/10.1063/1.1150281 (3 pages) | Cited 7 times

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Receiving higher emphasis on the neutral beam (NB) off-axis current drive, the NB system is being highlighted for the steady state operation of the International Thermonuclear Experimental Reactor (ITER). To fulfill the physics requirement of heating and current drive, the NB system delivers ∼50 MW of D0 beams at 1 MeV into the ITER plasmas. The NB injector was designed so as to minimize the axial length, to avoid cost impact on the building. It was estimated by nuclear analyses that the insulation gas around the beam source would cause radiation induced conductivity, which would result in a power dissipation of >100 kW in the gas itself. As a result the present design utilizes vacuum insulation around the beam source. Since the vacuum pressure inside/outside the beam source ranges 10−1–10−2 Pa, both gas (glow) and vacuum arc discharges are taken into account in the design. © 2000 American Institute of Physics.
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28.52.Cx Fueling, heating and ignition
52.50.Gj Plasma heating by particle beams
07.77.Ka Charged-particle beam sources and detectors

Computational studies on ion source plasmas of the neutral beam injection system

M. Kashiwagi, S. Ido, and Y. Okumura

Rev. Sci. Instrum. 71, 747 (2000); http://dx.doi.org/10.1063/1.1150282 (4 pages) | Cited 1 time

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A three-dimensional particle code taking into account the collision terms between fast electrons and hydrogen molecules is developed, where the elastic, ionization, excitation, and vibrational excitation collisions are calculated. This code is applied to investigate plasma generation and behavior in an ion source of the neutral beam injection system. It is found that the distribution of collision points is affected by grad-B drift when the gas pressure becomes lower. The sheath region around the filament is also taken into account, making it possible to optimize the filament shape and position in a plasma generator. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
52.65.Cc Particle orbit and trajectory
52.50.Gj Plasma heating by particle beams
52.40.Mj Particle beam interactions in plasmas
52.20.Fs Electron collisions
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.40.Hf Plasma-material interactions; boundary layer effects

Power flow in the negative-ion based neutral beam injection for JT-60

M. Kuriyama, N. Akino, N. Ebisawa, L. Grisham, S. Hikita, A. Honda, T. Itoh, M. Kawai, M. Kazawa, M. Kusaka, K. Mogaki, T. Ohga, Y. Okumura, H. Oohara, F. Satoh, et al.

Rev. Sci. Instrum. 71, 751 (2000); http://dx.doi.org/10.1063/1.1150283 (4 pages) | Cited 9 times

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The negative ion based neutral beam injection system for JT-60 has operated since 1996 injecting neutral beam into JT-60 plasmas. A power flow measurement in the beam line and ion source with a water calorimeter had shown that 40%–50% of accelerated beam particles were intercepted on the two accelerator grids and the grounded grid at an ion source gas pressure of 0.2–0.3 Pa. Much of the beam loss was not caused by stripping loss of the negative ions, but rather by direct impingement of the negative ions onto the grids. After reducing the acceleration area by masking the edge area (about 13% of the extraction area) of the accelerator grid so as to minimize the edge effect of magnetic field in the arc chamber, the loss in the accelerator decreased by roughly 25%. In comparing a deuterium beam with a hydrogen beam, the neutral beam power with deuterium is lower by 30% than that of hydrogen at the same arc power, although the heat load onto the grounded grid does not change so much. The power deposition ratios along the beamline were as follows: the beam scraper in the ion source tank and the neutralizer cell received about 3% and about 7%, respectively, of the accelerated beam power, while the ion dumps for both D− and D+ received 20%–30% in total, and 30%–34% reached the neutral beam calorimeter. © 2000 American Institute of Physics.
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52.55.Fa Tokamaks, spherical tokamaks
52.50.Gj Plasma heating by particle beams
52.40.Mj Particle beam interactions in plasmas

Study of plasma uniformity on JT-60U negative ion source

M. Kawai, L. Grisham, T. Itoh, M. Kazawa, M. Kuriyama, K. Mogaki, Y. Okumura, and K. Watanabe

Rev. Sci. Instrum. 71, 755 (2000); http://dx.doi.org/10.1063/1.1150284 (3 pages) | Cited 1 time

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The negative ion source developed at JAERI for the N-NBI was intended to accelerate a 500 keV, 22 A D− beam for 10 s. Two of these ion sources are mounted in the beamline. It has been found that the spatial uniformity of the source plasma is not as good as expected in the design phase of the negative ion sources for JT-60U. The source plasma uniformity has been estimated through measuring spatial distributions of the arc current flowing into each filament group and also the ion saturation current with Langmuir probes placed at ten positions around the extraction area of the plasma grid. We then altered the relative values of the arc current-limiting resistors to the eight filament groups in each source to balance the arc. As a result of the optimization of the arc resistors, the nonuniformity of the source plasma has been reduced. © 2000 American Institute of Physics.
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52.70.Ds Electric and magnetic measurements
07.77.Ka Charged-particle beam sources and detectors
29.25.Ni Ion sources: positive and negative

Alice ion source and its high voltage platform

M. Cavenago and T. Kulevoy

Rev. Sci. Instrum. 71, 758 (2000); http://dx.doi.org/10.1063/1.1150285 (3 pages) | Cited 2 times

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The electron cyclotron resonance ion source Alice is a small 14.4 GHz ion source intended to be a general purpose ion source for the ALPI ion linac. To increase the speed of emitted ions to more than 0.009 c it was installed on a high voltage platform. Noteworthy details of the platform complex such as the 400 kV insulation transformer with the power line connecting it to the platform and the acceleration tube are reviewed. The whole complex can operate up to 350 kV and up to 36 μA of extracted current, the current dispersed is small and upgrading to 400 kV looks possible. Details of the beam current, ion source optimization, source emittance and beam transport are discussed and show good agreement between experiments and calculated beam sizes. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors
29.20.-c Accelerators
29.27.Eg Beam handling; beam transport
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

D. P. Moehs, R. Vondrasek, R. C. Pardo, and D. Xie

Rev. Sci. Instrum. 71, 761 (2000); http://dx.doi.org/10.1063/1.1150286 (3 pages) | Cited 3 times

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A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd–Fe–B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid coils from the existing ECR will be enclosed in an iron yoke to produce the axial mirror. Based on a current of 500 A, the final model predicts a minimum B field of 3 kG with injection and extraction mirror ratios of 4.4 and 2.9, respectively. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
52.50.Gj Plasma heating by particle beams
84.32.Hh Inductors and coils; wiring

Ion source development for isotope separator on-line based radioactive nuclear beam facility at KEK-Tanashi

S. C. Jeong, H. Ishiyama, Y. Ishida, H. Kawakami, H. Kawashima, H. Miyatake, S. Mizutani, M. Oyaizu, S. Takaku, E. Tojyo, N. Yoshikawa, M. Wada, I. Katayama, and T. Nomura

Rev. Sci. Instrum. 71, 764 (2000); http://dx.doi.org/10.1063/1.1150287 (3 pages) | Cited 1 time

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For an isotope separator on-line based radioactive nuclear beam facility at KEK-Tanashi, two different types of ion sources are currently employed: a single stage 6.4 GHz electron cyclotron resonance ion source for 18Ne2+ and 19Ne2+ ions and a surface ionization-type ion source for 8Li1+ ions. The production target for Ne radioisotopes is LiF powder. Enclosed in a water-cooled Cu target cell, the target can sustain proton beam power of 120 W for a long term. The methods to suppress unwanted isotopes, like 19F in 19Ne and 18O in 18Ne, are discussed. For the production of 8Li1+ with the surface ionization-type ion source, a recoil-catcher method is adopted. The feasibility is discussed, comparing to a thick target method. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
28.60.+s Isotope separation and enrichment
32.10.Bi Atomic masses, mass spectra, abundances, and isotopes

Proton injector operational results on a high-power continuous-wave radio-frequency quadrupole accelerator

Joseph D. Sherman, Gerald O. Bolme, Lash D. Hansborough, Thomas W. Hardek, Debora M. Kerstiens, Earl A. Meyer, J. David Schneider, H. Vernon Smith, Matthew W. Stettler, Ralph R. Stevens, Michael E. Thuot, Thomas J. Zaugg, Adrian A. Arvin, Alvin S. Bolt, Patrick H. Hegler, et al.

Rev. Sci. Instrum. 71, 767 (2000); http://dx.doi.org/10.1063/1.1150288 (4 pages) | Cited 2 times

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A 50 keV proton injector utilizing a dc microwave source has been used to operate a 1.25 MeV continuous wave (cw) radio-frequency quadrupole (RFQ) accelerator. RFQ injection places stringent requirements on beam properties including centroid control, emittance, and phase-space matching. The ion source chosen for these applications is based on a microwave discharge operating at 2.45 GHz with an on-axis magnetic field near 875 G. The injector employs a space-charge-neutralized, two-solenoid-lens, low-energy beam transport (LEBT) system. Proton injector development with a 1.25 MeV RFQ has resulted in meeting the RFQ 75 mA design current specification in cw mode. Details of the ion source and LEBT operation are presented, and simulations for ion beam extraction and transport are compared with the injector measurements. The proton injector has been converted to 75 keV beam operation for injecting into a 6.7 MeV cw RFQ. © 2000 American Institute of Physics.
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29.27.Ac Beam injection and extraction
29.25.Ni Ion sources: positive and negative
29.27.Eg Beam handling; beam transport

TRIPS: The high intensity proton source for the TRASCO project

L. Celona, G. Ciavola, S. Gammino, R. Gobin, and R. Ferdinand

Rev. Sci. Instrum. 71, 771 (2000); http://dx.doi.org/10.1063/1.1150289 (3 pages) | Cited 10 times

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The TRASCO project (trasmutazione scorie) is a R&D program whose goal is the design of an accelerator driving system for nuclear waste transmutation. The high current continuous wave proton linear accelerator will drive a subcritical system to transmutate nuclear wastes, while producing energy. The proton source TRIPS is a high intensity microwave source, which should be highly reliable and that should provide a minimum proton current of 50 mA with a r−r′ root mean square normalized emittance lower than 0.2 π mm mrad. A program of cooperation has been entered into with CEA-Saclay, where the IPHI project is in progress and the proton source SILHI has been designed and built using goals close to those of TRIPS. The construction of TRIPS is underway and the first beam is scheduled for the first half of 2000. The main features of this source and the results of the optics calculations are presented. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
28.41.Kw Radioactive wastes, waste disposal
29.20.-c Accelerators
29.27.Ac Beam injection and extraction
52.50.Gj Plasma heating by particle beams

Status report on electron cyclotron resonance ion source operation at the Flerov Laboratory of Nuclear Reactions (Joint Institute for Nuclear Research) cyclotrons

V. B. Kutner, S. L. Bogomolov, A. A. Efremov, A. N. Lebedev, V. N. Loginov, and N. Yu. Yazvitsky

Rev. Sci. Instrum. 71, 774 (2000); http://dx.doi.org/10.1063/1.1150290 (3 pages) | Cited 1 time

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Two electron cyclotron resonance (ECR) sources, DECRIS-14-2 and ECR4M, are presently in permanent operation at the Flerov Laboratory of Nuclear Reactions cyclotrons, U400M and U400, respectively. A wide range of ions of gases from He up to Xe was delivered by the sources and accelerated in the cyclotrons. Major efforts were made in the production of high current stable ion beams of solids with relatively low melting points in mass ranges from Li up to Bi. Both the evaporator and the MIVOC technique were used. Among the solids a beam as exotic as 48Ca was produced at the U400 cyclotron with high efficiency. The main results on production of ion beams of gases and solids are reported. For further development of ECR ion sources a test bench was designed and built. The test bench is equipped with the new DECRIS-3 ion source. The parameters of the test bench and ECR source are described. © 2000 American Institute of Physics.  
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29.25.Ni Ion sources: positive and negative
29.27.Ac Beam injection and extraction
29.20.dg Cyclotrons
52.50.Gj Plasma heating by particle beams

A plan for on-line production and acceleration of radioactive isotope beams by use of electron cyclotron resonance ion source NANOGAN

K. Matsuta, M. Fukuda, M. Mihara, T. Minamisono, A. Mizobuchi, A. Kitagawa, T. Hattori, M. Sasaki, S. Kaminaka, K. Hashimoto, T. Tsubota, Y. Kobayashi, M. Sakamoto, and T. Sakurai

Rev. Sci. Instrum. 71, 777 (2000); http://dx.doi.org/10.1063/1.1150291 (3 pages)

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For the precise low background experiments on β decay and material sciences, we are planning to build a new ISOL-type facility to accelerate various β-radioactive nuclei utilizing the existing 5 MV Van de Graaff accelerator and an RFQ linac. Present status of the designing work is reported. In the present work, optical elements of the 41-m-long beam transport line to connect Van de Graaff accelerator and an RFQ linac were designed. Using two dipole magnets, two electric quadrupole doublets and six electric quadrupole triplets, low energy radioactive nuclear beams can be transported with sufficient efficiency. © 2000 American Institute of Physics.
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29.25.Lg Ion sources: polarized
29.27.Hj Polarized beams
29.27.Eg Beam handling; beam transport
29.20.-c Accelerators

Laser produced Ag ions for direct implantation

E. Woryna, J. Wolowski, B. Králiková, J. Krása, L. Láska, M. Pfeifer, K. Rohlena, J. Skála, V. Peřina, F. P. Boody, R. Höpfl, and H. Hora

Rev. Sci. Instrum. 71, 949 (2000); http://dx.doi.org/10.1063/1.1150354 (3 pages) | Cited 28 times

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The amount and properties of ions produced by laser ablation of Ag targets have been analyzed. The maximum ion current density jmax = 21.0 mA and maximum charge state Ar37+ of the ions produced by a laser power density of about 1×1014 W cm−2 at 1.315 and 0.657 μm on an Ag target have been determined. Direct implantation of the Ag ions from the laser-produced plasma has also been studied. An implanted ion density of 3.5×1016 cm−2 at a depth of 500 nm in Al samples was determined by RBS. © 2000 American Institute of Physics.
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61.72.up Other materials
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

High-current microwave ion source for wide-energy-range O+ ion implantation

K. Tokiguchi, T. Seki, J. Ito, T. Sato, and K. Mera

Rev. Sci. Instrum. 71, 952 (2000); http://dx.doi.org/10.1063/1.1150355 (3 pages) | Cited 3 times

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A high-current microwave ion source which is used for O+ ion implantation in separation by implanted oxygen (SIMOX) wafer fabrication is presented. The source consists of a new transform waveguide which efficiently propagates a 2.45 GHz microwave power into the ion source, a cylindrical plasma chamber of 90 mm in diameter, and a multiaperture extraction electrode system. The extracted beams are mass separated and then postaccelerated up to 200 keV. Ion source operates stably for a long time and the microwave absorption efficiency is as high as 80%. A total extraction current of 240 mA is obtained at the extraction voltage of 50–60 kV and the mass-separated O+ current reaches about 100 mA at the same extraction voltage. The data show that the ion source has a good potential to provide 100 mA-class O+ ion beams stably in the wide energy range demanded for SIMOX ion implantation. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
85.40.Ry Impurity doping, diffusion and ion implantation technology
61.72.uf Ge and Si
29.25.Ni Ion sources: positive and negative
29.27.Ac Beam injection and extraction

Production of Ce negative ions in a Cs sputter ion source

Y. Saitoh, B. Yotsombat, K. Mizuhashi, and S. Tajima

Rev. Sci. Instrum. 71, 955 (2000); http://dx.doi.org/10.1063/1.1150356 (3 pages) | Cited 2 times

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We have developed a new technique for stable production of lanthanide negative ions in a cesium sputter ion source without damage to the ionizer. Lanthanide elements sticking to a cesium ionizer deteriorate an ionization efficiency of the ionizer because of their characteristics such as low vapor pressures and low work functions. We have resolved the problem to make a sputter cathode that has a predrilled double layer structure. Cerium oxide powder pressed in the cathode pellet was covered by tungsten and drilled. Using this cathode, we achieved smaller solid angle emission of the sputtered lanthanide elements from the bottom of the drilled hole, and most of them could pass through the center hole of the ionizer. As a result, damage to the ionizer decreased, and stable operation of the ion source was successfully achieved with a cerium oxide beam current of 600 nA for 24 h continuous operation. The technique was applied for production of other rare earth ions. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Profile control of the large area ribbon beam ion source using 500 MHz ultrahigh frequency discharge

Shigeki Sakai, Masato Takahashi, and Masayasu Tanjyo

Rev. Sci. Instrum. 71, 958 (2000); http://dx.doi.org/10.1063/1.1150357 (2 pages) | Cited 3 times

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This article is concerned with the method of controlling the large area ribbon beam profile produced by the same extraction electrode size ion source. We used a bucket type large area ion source with 500 MHz ultrahigh frequency (UHF) discharge for the plasma production. The size of the ion source is comparable to one wavelength of 500 MHz rf. As the UHF wave propagates in the plasma, electrons are accelerated by the rf fields along the multicusp magnetic field produced by the peripheral permanent magnets set on the outer surface of the plasma chamber. We used several entrances of the UHF wave around the plasma chamber. We can control the ion beam profile by adjusting the size of the entrance hole. With this control, less than 2% of uniformity of the large area ion beam of 120 mm×220 mm is achieved for the source gases such as diborane, phosphine, and arsine. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors
52.80.Pi High-frequency and RF discharges

Change of diborane ion species depending on the magnitude of magnetic field using 100 MHz very high frequency discharge

Shigeki Sakai, Masato Takahashi, and Masayasu Tanjyo

Rev. Sci. Instrum. 71, 960 (2000); http://dx.doi.org/10.1063/1.1150358 (3 pages) | Cited 2 times

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In order to fabricate next generation semiconductor devices, low energy and high current doping ions are required to be transported. In particular the energy of boron ions is required to be less than 1 keV at a current of several mA. When hydrogen-diluted diborane is used as the ion source gas, usually hydrogen ions are also generated as well as borone hydride ions. But if the generation of the hydrogen ions is suppressed, mass separation may be unnecessary. Then the distance between the ion source and the target wafer can be shortened. As a result it becomes easy to transport low energy, high current ion beams. This work is concerned with a new method of plasma production which can suppress the hydrogen ion ratio in the very high frequency (VHF) discharge. We have improved the magnitude of multicusp magnetic field by changing the permanent magnet arrangement at the periphery of the plasma chamber, because the ratio of hydrogen ions strongly depends on the amount of high energy electrons which are produced through a relation between the VHF field and the multicusp field. Optimizing the magnitude of the magnetic field, the ratio of hydrogen ions can be reduced to less than 1% of the total ions. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors
52.80.Pi High-frequency and RF discharges
85.40.Ry Impurity doping, diffusion and ion implantation technology

Development of high intensity deuteron ion source for the fusion intense neutron source

M. Kinsho, M. Sugimoto, M. Seki, H. Oguri, and Y. Okumura

Rev. Sci. Instrum. 71, 963 (2000); http://dx.doi.org/10.1063/1.1150359 (3 pages)

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A high intensity deuteron ion source has been developed in order to increase the neutron flax from the D–T neutron source for Fusion Neutronics Source at JAERI. It is possible to extract more than 50 mA of deuteron beam at the beam energy of 50 keV. The lifetime of the tungsten filaments utilized in the ion source has been achieved in over 300 h with continuous operation. The high intensity deuteron ion source for the International Fusion Material Irradiation Facility is being designed on the basis of the experimental results and the experience obtained from the present ion source. © 2000 American Institute of Physics.
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29.25.Dz Neutron sources
29.25.Ni Ion sources: positive and negative
28.52.Fa Materials
29.27.Ac Beam injection and extraction

Experiments with a microwave plasma as a cathode for cold or hot reflex discharge ion source

G. Cojocaru

Rev. Sci. Instrum. 71, 966 (2000); http://dx.doi.org/10.1063/1.1150360 (3 pages)

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A microwave plasma cathode (MPC) was developed to replace the thermionic filaments of the cold or hot reflex discharge ion source (CHORDIS) ion source for operation with reactive gases. Experiments with our MPC showed its long lifetime and its capability of high-current electron emission. Two new types of antennae are presented. Different electron extraction apertures were used, but the best results were obtained with an extraction aperture of 6 mm in diameter. Ion beam currents for different oxygen pressures and different discharge voltages are presented and discussed. The gas pressure proved to be a critical parameter in respect to the extracted ion beam densities and beam noise. Total ion current densities of 16.8 mA/cm2 were obtained for oxygen. We are also presenting an experiment where the MPC-CHORDIS system was used as a tool to study the influence of the beam noise on the space charge compensation at the GSI Darmstadt injection beam line. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors
52.80.Pi High-frequency and RF discharges
52.50.Dg Plasma sources

High-current ion source development for the Korea Multipurpose Accelerator Complex

Y. S. Cho, B. H. Choi, I. S. Hong, and Y. S. Hwang

Rev. Sci. Instrum. 71, 969 (2000); http://dx.doi.org/10.1063/1.1150361 (3 pages) | Cited 1 time

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The Korea Multipurpose Accelerator Complex (KOMAC) project has been initiated to develop and build a high current proton/H− linear accelerator capable of delivering an 1 GeV cw proton beam with an intensity of 20 mA in the final stage. The major proton beam will be used for nuclear-waste transmutation, energy production, and nuclear physics experiments while utilizing the minor negative hydrogen beam for basic science research and medical therapy. A Duoplasmatron proton source for the KOMAC linear accelerator has been built at Korea Atomic Energy Research Institute. The hydrogen beam currents of up to 50 mA at the extraction voltage of 50 kV are routinely obtained. A low normalized rms emittance of 0.2 π mm mrad and a proton fraction of over 80% are obtained in this source. With the 100% duty factor of ion source operation, the arc filaments of the source have survived over 40 h. Except for the filament lifetime, the achieved parameters of the proton beam source are satisfying most requirements of the KOMAC ion source. The ion sources can extract the 10 mA nitrogen beam and 3 mA argon beam for the industrial surface modification processes. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative

Status of the HIMAC pulsed Penning source

T. Miyata, H. Sakamoto, M. Yamamoto, T. Okada, C. Kobayasi, Y. Honda, T. Fujimoto, W. Takasugi, T. Yokoyama, Y. Kageyama, T. Fukusima, H. Ogawa, H. Fujiwara, M. Muramatsu, A. Kitagawa, et al.

Rev. Sci. Instrum. 71, 972 (2000); http://dx.doi.org/10.1063/1.1150362 (3 pages) | Cited 2 times

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Since 1994 at the National Institute of Radiological Sciences HIMAC, the NIRS Penning ionized-gauge ion source (PIGIS) has so far been used for radiotherapy with carbon beams and for basic research with several ion species. The source can produce beams from H2 to Fe with a charge-to-mass ratio of between 1/7 and 1/2. It is a hot-cathode type with a filament, of which the lifetime is on the order of a week and the cathode on the order of 1 month, under a low-duty pulsed operation (⩽0.5%) synchronized to the ring operation. This PIGIS can produce highly charged ions: for example, 1 e mA of Ar7+ or 500 eμ A of Si5+ ions (by sputtering) under the typical arc power of 5 kW in peak. This article describes the present status of the NIRS-PIGIS. © 2000 American Institute of Physics.
Show PACS
29.25.Ni Ion sources: positive and negative
07.77.Ka Charged-particle beam sources and detectors
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