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Feb 2000

Volume 71, Issue 2, pp. 335-1239

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Electron beam ion sources in the reflex mode of operation (review and progress report) (invited)

E. D. Donets

Rev. Sci. Instrum. 71, 810 (2000); http://dx.doi.org/10.1063/1.1150301 (6 pages) | Cited 11 times

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The reflex mode of electron beam ion source (EBIS) operation can provide repeated use of electrons, emitted by the gun cathode both for sequential ionization of positive ions and for creation of negative space charge to keep ions in an electrostatic ion trap of the source. This mode of operation provides as well a corresponding decrease of a consumed electric power compared to the electron beam power in the normal mode of EBIS operation. The studies of the reflex mode resulted in an observation of a transition to the so-called electron string state. Electron energy distributions in the strings differ from those in electron beams. Electron strings are used for production of highly charged ions. The sequence of the ion production in a string is the same as in an electron beam. The first review of experimental methods and experimental results, including the latest ones and of the first attempts to give a theoretical description of the reflex mode, is presented. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
52.55.Lf Field-reversed configurations, rotamaks, astrons, ion rings, magnetized target fusion, and cusps
01.30.Rr Surveys and tutorial papers; resource letters
07.77.Ka Charged-particle beam sources and detectors

Electron beam ion sources and traps (invited)

Reinard Becker

Rev. Sci. Instrum. 71, 816 (2000); http://dx.doi.org/10.1063/1.1150302 (4 pages) | Cited 4 times

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The electron beam method of stepwise ionization to highest charge states has found applications in electron beam ion sources (EBISs) for accelerators and atomic physics collision experiments as well as in electron beam ion traps (EBITs) for x-ray and mass spectroscopy. A dense and almost monoenergetic electron beam provides a unique tool for ionization, because radiative recombination by slow electrons is negligible and charge exchange is almost avoided in ultrahigh vacua. These are essential differences to electron cyclotron resonance ion sources with inevitable low energy electrons and comparatively high gas pressure. The distinction between EBIS and EBIT as genuine devices has become meaningless, because EBISs may work as traps and almost all EBITs are feeding beamlines for external experiments. More interesting is to note the diversification of these devices, which demonstrates that a matured technology is finding dedicated answers for different applications. At present we may distinguish six major lines of development and application: high current EBISs for upcoming hadron colliders, super EBITs in the energy range above 300 keV for quantum electrondynamics tests, inexpensive and small EBISTs for atomic physics studies, a highly efficient EBIS with oscillating electrons, MEDEBIS for tumor therapy with C6+, and charge breeding in facilities for exotic radioactive beams. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
29.25.Ni Ion sources: positive and negative

Simulation of ion extraction and beam transport (invited)

P. Spädtke and C. Mühle

Rev. Sci. Instrum. 71, 820 (2000); http://dx.doi.org/10.1063/1.1150303 (6 pages) | Cited 7 times

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The three dimensional code KOBRA3 has been used to simulate nonsymmetric extraction systems such as from an electron cyclotron resonance (ECR) ion source and a Penning ion source (PIG). For the ECR case the particle distribution is nonsymmetric due to the hexapole magnet. The PIG source extraction is usually a slit in magnetic field direction. The extracted ion beams usually cannot be transported without space charge compensation. The creation and behavior of the compensating particles and the resulting beam transport has been simulated with KOBRA3 as well. The applied model in the simulation describing this compensation is similar to the model used for space charge compensation in the plasma for extraction problems. Good agreement of the simulations with the experimental results has been obtained. © 2000 American Institute of Physics.
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29.25.Ni Ion sources: positive and negative
29.27.Ac Beam injection and extraction
29.27.Eg Beam handling; beam transport

Status of vacuum arc ion sources (invited) (abstract)

Ian Brown

Rev. Sci. Instrum. 71, 826 (2000); http://dx.doi.org/10.1063/1.1150304 (1 page)

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Vacuum arc ion sources have been developed and used in a growing number of laboratories around the world. Beams have been produced from most of the solid metals of the periodic table as well as alloys and mixtures, with ion energy up to several hundred keV and beam current up to several A. Typically the source is repetitively pulsed with a pulse length on the order of a millisecond and duty cycle of 1%, and dc operation has been demonstrated also. The main application has evolved for ion implantation, primarily for metallurgical, ceramic, and polymer surface modification (i.e., nonsemiconductor applications), but also for semiconductor implantation in some special cases; the source is also used for heavy ion injection into particle accelerators. This kind of high-current metal ion source has provided a valuable addition to the spectrum of ion sources available to the experimenter. Here the source fundamentals are briefly reviewed and the source performance and beam characteristics summarized. We survey some of the vacuum arc ion source development that has been accomplished over the past decade at many laboratories around the world, applications to which the source has been put, and recent progress in source innovations that has been accomplished by the community. © 2000 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
52.80.Vp Discharge in vacuum
01.30.Rr Surveys and tutorial papers; resource letters
29.25.Ni Ion sources: positive and negative

Pulsed vacuum-arc ion source operated with a “triggerless” arc initiation method

A. Anders, J. Schein, and N. Qi

Rev. Sci. Instrum. 71, 827 (2000); http://dx.doi.org/10.1063/1.1150305 (3 pages) | Cited 12 times

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Vacuum arcs can be initiated by simply applying a sufficiently high voltage (∼ 1 kV) between the anode and cathode, provided that there is a conducting path between these electrodes. Typically, the conducting path is obtained by coating the ceramic insulator. Plasma is formed explosively at the coating-cathode interface. Since neither a trigger supply nor a trigger electrode are required, the method has been dubbed “triggerless” arc initiation. Triggerless operation of a vacuum arc ion source was demonstrated for a number of cathode materials. It was found that triggerless operation is very reliable as long as the balance of deposition and erosion of the conducting material leads to a steady-state path resistance in the range from 1 Ω to 100 kΩ. © 2000 American Institute of Physics.
Show PACS
07.77.Ka Charged-particle beam sources and detectors
29.25.Ni Ion sources: positive and negative
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
52.80.Vp Discharge in vacuum
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