摘要:

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.

ISSN:0034-6748    

DOI:10.1063/1.1144756

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Following the pioneering work on metal vapor vacuum arc (MEVVA) ion sources at Lawrence Berkeley Laboratory by Brown and co‐workers, the Australian Nuclear Science and Technology Organization (Ansto) commenced a program of research aimed at constructing a MEVVA based ion implanter. This phase of the program has been completed and the system is now in routine use for surface modification studies. The purpose of the present article is to give an overview of the Ansto implanter with particular reference to those features, such as triggering reliability, which entailed some developmental work. Finally, current ion implantation research activities on this system are briefly described.

ISSN:0034-6748    

DOI:10.1063/1.1144757

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Work on metal vapor vacuum arc (MEVVA) ion source development was initiated at the Institute of Low Energy Nuclear Physics, Beijing Normal University, in 1988. MEVVA ion sources I, II, IIA, and III have been designed, fabricated, and tested, and an ion implantation facility with three MEVVA ion sources has been developed and is now undergoing testing. Here the status of the MEVVA ion source research and development program is described.

ISSN:0034-6748    

DOI:10.1063/1.1144758

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

High current metal ion production is a challenging task for ion source designers. The MEVVA ion source has proven to be a useful tool for accelerator injection and for ion implantation. We have investigated the MEVVA ion source in connection with the GSI heavy ion accelerators. At the Unilac accelerator as injector for the heavy ion Synchrotron SIS (1 Hz and 100 &mgr;s pulse length) the MEVVA can deliver mA beams of multiply charged ions up to 3+ (or mass to charge ratio of ≤24 accepted by Unilac). At the 300 kV ion implantation facility the MEVVA is used to inject metal ions into the RFQ accelerator with duty cycles above 1%. Here we discuss the ion beam currents and charge state distributions for various ion species and beam formation and transport at the accelerators. Space‐charge effects and ion beam instabilities are discussed in detail. At the Unilac injector results with titanium and nickel from the MEVVA ion source are compared with those of neon from a CHORDIS gas ion source.

ISSN:0034-6748    

DOI:10.1063/1.1144759

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A new variant of vacuum arc ion source is described whereby the problems of short cathode lifetime and low charge states, commonly found for low boiling point cathode materials, are avoided. This novel source embodiment has been operated using bismuth as the wanted ionic species. It was found that the ion charge state spectrum can be improved (i.e., increased) significantly, with the charge state of maximum amplitude being increased from Bi1+to Bi3+, and the number of pulses that were obtained before the cathode needed changing was 108.

ISSN:0034-6748    

DOI:10.1063/1.1144760

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A MEVVA (metal vapor vacuum arc) ion source has been made and tested at the Institute of Theoretical and Experimental Physics (ITEP), Moscow. The ions are created in the plasma formed from the cathode metal vapor of a vacuum arc discharge. An ion beam current of about 200–400 mA in repetitively triggered pulses of width 0.1 ms has been obtained. The ion charge state distributions have been measured for seven elements (Be,C,Al,Fe,Cu,Zr,W) and they are in reasonable agreement with results of other workers. The MEVVA ion source is simple to operate and has a reliability acceptable for use as an ion source for ITEP synchrotron injection.

ISSN:0034-6748    

DOI:10.1063/1.1144761

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A version of vacuum arc ion source has been developed and constructed at the Institute for Theoretical and Experimental Physics, Moscow, for use with a heavy ion radio frequency quadrupole linac. The source is operated in a pulsed mode with a pulse length from 5 to 120 &mgr;s and a repetition rate of from 1/8 to 1 pps. The injection voltage is up to 90 kV depending on the kind of ions being used, and the beam current at the injector output is up to 500 mA. The results described in this article were made at a beam current of from 10 to 100 mA. In order to obtain ions having a charge‐to‐mass ratio of about 1/60, metals such as Cu, Mo, Ta, W, and Pb were used as the cathode material. Volt‐ampere characteristics and charge state distributions were measured. The charge state spectral variation was investigated throughout the arc current pulse duration as well as the dependence of the mean charge state of the beam ions on the melting point of the cathode material.

ISSN:0034-6748    

DOI:10.1063/1.1144762

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The beam extracted from the MEVVA ion source tends to be of a relatively high noise level, particularly for the higher charge states, making beam transport difficult in accelerator application. This paper presents experimental results which show that the use of grids within the ion source in combination with a solenoidal magnetic field can decrease the noise of the extracted beam considerably. The noise reduction can be explained by an increase in plasma density due to the applied magnetic field and space charge limitation of the extracted ion beam current.

ISSN:0034-6748    

DOI:10.1063/1.1144763

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The presence of background gas in the discharge chamber of the metal vapor vacuum arc source influences the extracted beam. We have observed a strong influence of the background gas pressure in the arc region on the total extracted beam current and on the charge state distribution of the metallic ions. Different gases have been investigated together with different cathode materials. Up to 90% of the total beam current can be gaseous ions, depending on the arc and gas injection conditions.

ISSN:0034-6748    

DOI:10.1063/1.1144764

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

TITAN is a new type of ion source capable of generating high current, wide aperture beams of gas and metal ions from a broad range of elements: Mg, Al, Ti, Cr, Fe, Co, Ni, Sm, Zn, W, Pb, Ta, Re, Y, C, He, N, Ar, and Xe. A specific feature of the TITAN ion source is the use of two kinds of arc discharges, each with cold cathodes, to produce plasma for ion beam extraction. Metal ions are generated by means of the vacuum arc in the metal vapor formed in cathode spots. Gas ions, on the other hand, are provided by a low‐pressure constricted arc discharge. In a pulsed mode of operation the extraction voltage of the source ranges from 10 to 100 kV. The pulsed beam current for gas and metal ions is on the order of 1 A at pulse repetition rates up to 50 pulses per second and pulse duration of ∼400 &mgr;s. For dc operation and at an extraction voltage up to 10 kV, the ion current is as high as hundreds of milliamperes. This work outlines briefly the ion source, its design, and certain physical peculiarities observed when a high current ion beam is generated and transported.

ISSN:0034-6748    

DOI:10.1063/1.1144765

出版商:AIP    

年代:1994

数据来源: AIP