The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. The beam parameters can be attractive, and the source has provided a valuable addition to the spectrum of ion sources available to the experimenter. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with beam current up to several amperes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle of order 1%, and operation of a dc embodiment has been demonstrated. Here the source fundamentals and operation are reviewed, the source and beam characteristics summarized, and some applications examined.

https://cds.cern.ch/record/1693045/files/p311.pdf

Vacuum Arc Ion Sources

Ion beam assisted deposition (IBAD) is a coating technique which combines a thin‐film deposition method such as evaporation with irradiation by highly energetic ions from an ion source. Application of an ion source and a vapor source which are operated independently of each other render the IBAD technique highly controllable, reproducible, and flexible. Ion flux, atom flux, ion energy, ion impact angle, and other parameters can be controlled independently over a wide range. In order to take advantage of the beneficial features of this technique and obtain optimum process conditions ion sources with special properties are required. In this article different ion source types and equipment which has been used for IBAD to‐date are presented and their special features discussed. Ion sources which should be applicable for IBAD are described. Finally, general requirements of IBAD ion sources are discussed.

Ion sources for ion beam assisted thin‐film depositiona)

High current beams of metal ions can be produced efficiently using a metal vapor vacuum arc to establish the metal plasma from which the beam is formed. Pulsed beam currents of several amperes of metallic ions have been produced from nearly all of the solid metals of the periodic table, and in some recent tests dc beams have been produced also. Beam extraction voltage up to 100 kV has been used and since the ions produced in the vacuum arc plasma are in general multiply ionized the ion energy is up to several hundred keV. These kinds of sources are finding application for heavy‐ion synchrotron injection, metallurgical ion implantation, and other uses. A number of different embodiments of the source have been developed at Berkeley and elsewhere around the world. Interesting features include multiple cathodes and the ability to switch between up to 18 separate cathode materials simply and quickly, and broad beam source versions (up to 50 cm diameter) as well as miniature versions (about ‘‘thumb size’’). Her...

Metal vapor vacuum arc ion sources (invited)

An experimental approach for linking the atomic mass unit to the kilogram with an uncertainty sufficiently small for a future re-definition of the kilogram is described. The concept consists of accumulation of ions from an ion beam up to a weighable mass and measurable total charge. The main problems and influencing factors connected with ion beam technology, weighing and current measurement together with the corresponding experimental solutions are discussed in detail. The first experiments with consistent results, but still large uncertainty, are described.

Tracing the atomic mass unit to the kilogram by ion accumulation

The vacuum arc is a generator of highly ionized metal plasma. This method of plasma production can be used to construct a high-current metal ion source. A succession of such metal-vapor vacuum arc ion sources has been developed at Berkeley. Beams from 50 of the solid metals of the periodic table have been produced with mean ion energy up to several hundred keV, and with pulsed beam currents in the ampere range. Typically the source is repetitively pulsed with a pulse length of 250 mu s and a duty cycle of the order of 1%. A DC embodiment from which a large-area titanium beam with steady-state ion current of 600 mA was produced has been tested. A 50-cm-diameter set of beam formation grids has been used to form a beam of area 1000 cm/sup 2/ at an energy of 100 keV and a pulsed beam current of approximately 10 A. The source can also be seen as a tool for the study of vacuum arc plasmas. Vacuum arc ion charge state distributions have been studied in this way. The general features and performance characteristics of the sources and their use for accelerator injection and ion implantation applications are described. >

Bo Torp

Papers

High current metallic ion beams