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

722,494. Supply systems for welding arcs. AIR REDUCTION CO., Inc. Dec. 8, 1952 [Dec. 28, 1951], No. 31074/52. Drawings to Specification. Class 38 (4). To permit the employment of a relatively low high-frequency (say 50 to 500 kcs. per sec.) current for starting and stabilizing a D.C. or low-frequency A.C. welding arc, the highfrequency inductor or transformer disposed in the welding circuit and necessary for the injection of the high-frequency current has a core of ferrite material or powdered iron and is arranged to saturate at normal welding currents so as to offer little impedance to the flow of welding current, but to be unsaturated by the high-frequency currents alone, so as to offer high impedance to these-and thus provide good injection of high-frequency currentwhen the arc extinguishes. The high-frequency generator may comprise a push-pull valve oscillator normally cut off by external bias, but triggered into oscillation by a voltage pulse induced in a winding of the injection transformer upon interruption of the flow of welding current.

Electric arc welding

▪ Abstract Cathodic arc deposition is a plasma-based technology for the fabrication of films. The process can be carried out either at high vacuum or in a low pressure gaseous environment, and films can be formed for example of metals, ceramics, diamond-like carbon, some semiconductors and superconductors, and more. The plasma stream can be filtered to remove microdroplet contamination, and the ion energy can be controlled by substrate bias, thereby transforming the straightforward deposition method into hybrids with other surface modification processes such as ion beam–assisted deposition, ion beam mixing, and ion implantation. The method provides a versatile and powerful plasma tool for the synthesis of novel and technically important surfaces.

Cathodic arc deposition of films

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A new kind of high current metal ion source in which the ion beam is extracted from a metal vapor vacuum arc plasma has been used to obtain the spectra of multiply charged ions produced within the cathode spots. The cathode materials used and the species reported on here are: C, Mg, Al, Si, Ti, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, In, Sn, Gd, Ho, Ta, W, Pt, Au, Pb, Th, and U; the arc current was 200 A for all measurements. Charge state spectra were measured using a time‐of‐flight method. In this paper we report on the measured charge state distributions and arc voltages and compare the distributions with the predictions of a theory in which ionization occurs in the cathode spots via stepwise ionization by electron impact.

/pdf/multiply-stripped-ion-generation-in-the-metal-vapor-vacuum-48rzgqfkoh.pdf

Multiply stripped ion generation in the metal vapor vacuum arc

A high‐current ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ion beam is extracted. An ion beam current of up to about 1 A has been measured at an extraction voltage of 25 kV for a range of metallic species spanning the periodic table from lithium to uranium. Multiply ionized charge states are seen up to as high as Q=6+ in the case of uranium. In the metal vapor vacuum arc, regions of intense current concentration are formed at the cathode, and it is at these regions, the cathode spots, that the cathode material is vaporized and ionized to form a dense, quasi‐neutral plasma which plumes away from the cathode surface. The plasma plume is caused to impinge upon a set of extractor grids, and the ion beam is extracted from the streaming metal plasma. A preliminary survey of the performance of the source has been made. We describe here the principle of operation of the source, the source design, and the results of those measurements that we have made to date.

/pdf/metal-vapor-vacuum-arc-ion-source-1xv30s4pvb.pdf

Metal vapor vacuum arc ion source

A history of the development of a successful, high-power vacuum interrupteris presented. This covers two principal phases: (1) early engineering effort in the late 1920's and early 1930's to produce a commercial interrupter, and (2) a review of the research and engineering at the General Electric Company covering new technologies necessary for the development of the high-power vacuum interrupter. A short review of the literature is included.

Research and Development Leading to the High-Power Vacuum Interrupter- A Historical Review

Hydrogen reduction method and apparatus

A study has been made of the breakdown and recovery strength characteristics of experimental vacuum interrupters incorporating a variety of contact materials. Our data show that much of the breakdown strength for these devices is gained in less than a 1/8-inch gap length. Experiments using a synthetic test system indicate that these experimental switches recover nearly all of their breakdown strength in 1 to 15 ?sec (microseconds) after the cessation of peak arc current ranging from 400 to 3,200 amp (amperes).

Recovery characteristics of vacuum arcs

Measurements are reported for the recovery of electric strength following interruption of an arc drawn in nitrogen at pressures ranging from atmospheric to 0.02 torr. These data are compared with similar results obtained for vacuum arcs. Recovery strength measurements followed a single half-cycle of sinusoidal arc current with a peak of 400 amperes. For conditions of gap length and pressure described by the Paschen curve minimum, full recovery is reached in a time less than a few micro-seconds. The voltage corresponding to full recovery is essentially determined by contacts, their separation, and ambient gas pressure.

Recovery Strength Measurements in Arcs from Atmospheric Pressure to Vacuum

The problem of current chopping in the vacuum interrupter is considered and various reasons for the occurrence of this phenomenon are explored. Metals with high vapor pressure were found to be most suitable for the maintenance of an arc at low currents in vacuum, and have been utilized for the solution of the current chopping problem in vacuum interrupters. There is some evidence that the presence of low work function materials also enhances arc stability.

http://ieeexplore.ieee.org/iel5/6367273/6373362/06373384.pdf

James D Cobine

Papers

Research and Development Leading to the High-Power Vacuum Interrupter- A Historical Review

Hydrogen reduction method and apparatus

Recovery characteristics of vacuum arcs

Recovery Strength Measurements in Arcs from Atmospheric Pressure to Vacuum

Electrode materials and their stability characteristics in the vacuum arc