Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources

2021 ◽  
Author(s):  
Sheng Hui Fu ◽  
Li Cheng Tian ◽  
Zhen- Feng Ding
Keyword(s):  
Electron Cyclotron Resonance ◽  
Voltage Drop ◽  
Ion Beam ◽  
Energetic Electron ◽  
Underlying Mechanism ◽  
Beam Current ◽  
Ion Source ◽  
Ion Sources ◽  
Direct Excitation ◽  
Screen Grid

Abstract Thus far, effects of secondary γ-electrons emitted from accelerator grids of gridded ion sources on ionization in discharge chambers have not been studied. The presence and induced processes of such secondary electrons in a microwave electron cyclotron resonance gridded ion source are confirmed by the consistent explanations of: (1) the observed jump of ion beam current (Ib) in case of a low-density plasma appearing at the chamber’s radial center due to the microwave skin effect; (2) the evolution of glow images recorded from the end-view of the ion source during the jump of Ib; (3) the over-large jump step of Ib with the increasing microwave power; (4) the pattern appearing on the temperature sticker exposed to the discharge operated in the regime where the arrayed energetic-electron beamlets are injected into the discharge chamber; (5) the measured step-increment in the voltage drop across the screen grid sheath. A positive feedback loop composed of involved processes are established to elucidate the underlying mechanism. Energetic γ-electrons from the accelerator grid and warm δ-electrons from the opposite antenna do not produce direct excitation and ionization, but they enhance the electrical confinement of cold electrons by elevating the voltage drop across the sheaths at the antenna and screen grid, thus leading to the jump of Ib. The energetic γ-electrons-based model can be also modified to explain abnormal results observed in the other gridded ion sources. Energetic γ-electrons from accelerator grids should be taken into account in understanding gridded ion sources.

Development of high-current ionic liquid ion source toward surface modification

2013 ◽  
Vol 1575 ◽  
Author(s):  
Mitsuaki Takeuchi ◽  
Takuya Hamaguchi ◽  
Hiromichi Ryuto ◽  
Gikan H Takaoka
Keyword(s):  
Ionic Liquid ◽  
Surface Modification ◽  
Flow Rate ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Source ◽  
Ion Sources ◽  
Ion Current ◽  
High Current ◽  
Beam Characteristics

ABSTRACTIonic liquid (IL) ion sources with different emitter tip materials and tip numbers were developed and examined on ion beam characteristics with respect to its ILs wettability. As a result of ion current measurements, the most stable emission current was obtained for the graphite emitter tip and the ion current increased with increase of the tip number. The results indicate that the emitter wettability corresponding to the supplying flow rate and the number of emission site play an important role to stabilize and increase the beam current.

Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source

2012 ◽  
Vol 83 (2) ◽  
pp. 02A310 ◽  
Author(s):  
Yosuke Kurisu ◽  
Ryutaro Kiriyama ◽  
Tomoya Takenaka ◽  
Dai Nozaki ◽  
Fuminobu Sato ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Source ◽  
Electron Cyclotron

Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source

2012 ◽  
Vol 83 (2) ◽  
pp. 02A333 ◽  
Author(s):  
Y. Higurashi ◽  
J. Ohnishi ◽  
T. Nakagawa ◽  
H. Haba ◽  
M. Tamura ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Ion Source ◽  
Electron Cyclotron ◽  
Uranium Ion

Alloy surface composition resulting from fabrication, as determined by s.i.m.s. (secondary ion mass spectrometry)

1980 ◽  
Vol 295 (1413) ◽  
pp. 134-135
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Surface Composition ◽  
Ion Beam ◽  
Sample Surface ◽  
Beam Current ◽  
Ion Source ◽  
Beam Current Density ◽  
Dynamic Mode ◽  
Static Mode ◽  
Subsequent Performance

In s.i.m.s. the sample surface is ion bombarded and the emitted secondary ions are mass analysed. When used in the static mode with very low primary ion beam current densities (10 -11 A/mm 2 ), the technique analyses the outermost atomic layers with the following advantages (Benninghoven 1973, I975): the structural—chemical nature of the surface may be deduced from the masses of the ejected ionized clusters of atoms; detection of hydrogen and its compounds is possible; sensitivity is extremely high (10 -6 monolayer) for a number of elements. Composition profiles are obtained by increasing the primary beam current density (dynamic mode) or by combining the technique in the static mode with ion beam machining with a separate, more powerful ion source. The application of static s.i.m.s. in metallurgy has been explored by analysing a variety of alloy surfaces after fabrication procedures in relation to surface quality and subsequent performance. In a copper—silver eutectic alloy braze it was found that the composition of the solid surface depended markedly on its pretreatment. Generally there was a surface enrichment of copper relative to silver in melting processes while sawing and polishing enriched the surface in silver

scholarly journals Upgrading the ECR ion source within FAMA

2018 ◽  
Vol 33 (1) ◽  
pp. 47-52
Author(s):  
Andrey Efremov ◽  
Sergey Bogomolov ◽  
Vladimir Bekhterev ◽  
Aleksandar Dobrosavljevic ◽  
Nebojsa Neskovic ◽  
...  
Keyword(s):  
Electron Cyclotron Resonance ◽  
Ion Beam ◽  
Ion Source ◽  
Vacuum System ◽  
Multiply Charged Ions ◽  
Inlet System ◽  
Multiply Charged ◽  
Microwave System ◽  
Beam Currents ◽  
Charged Ions

Recent upgrading of the Facility for Modification and Analysis of Materials with Ion Beams - FAMA, in the Laboratory of Physics of the Vinca Institute of Nuclear Sciences, included the modernization of its electron cyclotron resonance ion source. Since the old ion source was being extensively used for more than 15 years for production of multiply charged ions from gases and solid substances, its complete reconstruction was needed. The main goal was to reconstruct its plasma and injection chambers and magnetic structure, and thus intensify the production of multiply charged ions. Also, it was decided to refurbish its major subsystems - the vacuum system, the microwave system, the gas inlet system, the solid substance inlet system, and the control system. All these improvements have resulted in a substantial increase of ion beam currents, especially in the case of high charge states, with the operation of the ion source proven to be stable and reproducible.

Current stability to improve AMS precision for cosmogenic 10Be applications

2021 ◽  
Author(s):  
Ana Carracedo Plumed ◽  
Derek Fabel ◽  
Richard Shanks
Keyword(s):  
Metal Matrix ◽  
Ion Beam ◽  
Beam Current ◽  
Ion Sources ◽  
Precipitation Process ◽  
Case Scenario ◽  
Series Of Experiments ◽  
Counting Statistics ◽  
Beam Currents ◽  
Cosmogenic 10Be

<p>With the present AMS <sup>10</sup>Be uncertainties (~2% best case scenario) and the increasing need for more precise cosmogenic <sup>10</sup>Be data it has become imperative to improve AMS measurements. Precision depends on counting statistics which in turn depend on ion beam current stability and sample longevity. The ion beam currents are dependent on the metal matrix in which BeO is dispersed; the matrix:BeO ratio; homogeneity of the mixture and the packing of the AMS cathode. We aim to understand the effect of cathode homogeneity in generating stable beam currents. We have performed a series of experiments using different metal matrices (Nb, Ag, Fe) in different forms (solid and in solution). The metals have been added to different stages of the sample precipitation process and both BeO and Be(OH)<sub>2</sub> have been pressed into AMS cathodes and analysed at SUERC. We will discuss results of these experiments and introduce an innovative use of polyoxometalates (molibdanate and niobate) to create a homogeneous compound that has the potential to generate stable ion beam currents from sputter ion sources.</p>

Ion Sources for Ion Beam Assisted Thin Film Deposmon

1995 ◽  
Vol 396 ◽  
Author(s):  
Igor V. Svadkovsk ◽  
Anatoly P. Dostanko
Keyword(s):  
Ion Beam ◽  
Ion Source ◽  
Ion Sources ◽  
Inert Gases ◽  
Anode Layer ◽  
High Current ◽  
Ion Beam Assisted Deposition ◽  
Ion Energies ◽  
Extended Range ◽  
Basic Distinction

AbstractTwo types of the ion sources for ion beam assisted deposition using inert gases, oxygen or nitrogen are reported. Their design and operational features are presented. Each of them has the properties of two existing main types of the gridless Hall sources: an end-Hall source and the anode-layer version a closed-drift ion source. Basic distinction of the developed sources is the extended range of ion energies in high-current beam for optimization of deposition, cleaning and etching processes.

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