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in creator/contributor: "Brown, I."

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Scaling for Tormac fusion reactors

In this paper a set of parameters for a Tormac reactor is developed. The scaling indicates that a Tormac reactor could be constructed with a modest energy output of about 500 megawatts with magnetic fields averaging 20 kG, peak fields of 40 kG, and a plasma radius of about two meters. Wall loading under these conditions can be kept modest. It is further noted that Tormac can be run in a steady state mode. Thus, Tormac makes an economically attractive alternative to tokamak.

Date: April 1, 1976

Creator: Levine, M. A.; Brown, I. G. & Kunkel, W. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Increasing the retained dose by plasma immersion ion implantation and deposition

The retained dose of ions can be increased by Plasma Immersion Ion Implantation and Deposition (PIIID). A substrate is immersed in a metal or carbon plasma and a negative repetitively pulsed bias voltage is applied. During the pulses, an electric sheath is formed around the substrate and ions are accelerated through the sheath and implanted into the substrate. Direct and recoil ion implantation and sputtering take place during the pulses whereas low-energy deposition occurs between the pulses. … more

Date: July 22, 1994

Creator: Anders, A.; Anders, S.; Brown, I. G. & Yu, Kin M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Formation of buried epitaxial Si-Ge alloy layers in Si<100>crystal by high dose Ge ion implantation

We have synthesized single crystal Si{sub 1-x}Ge{sub x} alloy layers in Si <100> crystals by high dose Ge ion implantation and solid phase epitaxy. The implantation was performed using the metal vapor vacuum arc (Mevva) ion source. Ge ions at mean energies of 70 and 1000 keV and with doses ranging from 1{times}10{sup 16} to 7{times}10{sup 16} ions/cm{sup 2} were implanted into Si <100> crystals at room temperature, resulting in the formation of Si{sub 1-x}Ge{sub x} alloy layers with peak Ge con… more

Date: November 1, 1991

Creator: Yu, Kin Man; Brown, I. G. & Im, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of resonant microwave power on a PIG ion source

We have investigated the effect of applying microwave power at the electron cyclotron frequency on the characteristics of the ion beam extracted from a hot-cathode PIG ion source. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and it is possible that the technique may find application in situations where beam quiescence is important. 29 references, 2 figures.

Date: August 1, 1984

Creator: Brown, I.G.; Galvin, J.E.; Gavin, B.F. & MacGill, R.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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LBL EBIS test-strand

An EBIS program was initiated at Lawrence Berkeley Laboratory in late 1979. This first stage, construction of an EBIS research and development test-stand is described, along with results of the bare beam experiments.

Date: May 1, 1981

Creator: Feinberg, B. & Brown, I.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Broad-Beam, High Current, Metal Ion Implantation Facility

We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to seve… more

Date: July 1, 1990

Creator: Brown, I. G.; Dickinson, M. R.; Galvin, J. E.; Godechot, X. & MacGill, R. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Metal vapor vacuum arc ion sources

We have developed a family of metal vapor vacuum are (MEVVA) high current metal ion sources. The sources were initially developed for the production of high current beams of metal ions for heavy ion synchrotron injection for basic nuclear physics research; more recently they have also been used for metal ion implantation. A number of different embodiments of the source have been developed for these specific applications. Presently the sources operate in a pulsed mode, with pulse width of order … more

Date: June 1, 1990

Creator: Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X. & MacGill, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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An improved time-of-flight ion charge state diagnostic

A time-of-flight diagnostic for analysis of relatively low energy ion beams is described. The system incorporates several novel features which improve its performance in a number of ways. The technique is simple and can provide an alternative to magnetic analysis of ion beams for the determination of ion charge state and beam composition.

Date: March 1, 1987

Creator: Brown, I.G.; Galvin, J.E.; MacGill, R.A. & Wright, R.T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Status of the MEVVA (Metal Vapor Vacuum Arc) high current metal ion source. [Metal Vapor Vacuum Arc]

The MEVVA (Metal Vapor Vacuum Arc) ion source that has been developed at LBL was reported on for the first time at the 1985 Particle Accelerator Conference (1). This source can produce hundreds of milliamperes of beam current of metal species from lithium up to uranium. In the period since then we have developed the source further, and this work is summarized here. We have now run the source with over 30 different beam species, and with an extraction voltage up to 110 kV. We have made and opera… more

Date: March 1, 1987

Creator: Brown, I.G.; Galvin, J.E.; MacGill, R.A. & Wright, R.T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Vacuum arc ion charge state distributions

We have measured vacuum arc ion charge state spectra for a wide range of metallic cathode materials. The charge state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. We have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, … more

Date: June 1, 1990

Creator: Brown, I.G. & Godechot, X.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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On the Current Intensity Limit of a Vacuum Arc Ion Source

The maximum ion current that can be produced as a high energy beam from a metal vapor vacuum arc ion source is considered. Results are presented of measurements of the plasma ion current in the MEVVA II ion source. It is shown that this source is an efficient generator of metal ions, an intense flux of which is efficiently transported to the beam extractor. The maximum metal ion current that is available for extraction at the extractor location is 5% of the arc current. The limitation to the in… more

Date: March 1987

Creator: Brown, I. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Multiply stripped ion generation in the metal vapor vacuum arc

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A high current metal ion source, the MEVVA ion source, in which the ion beam is extracted from a metal vapor vacuum arc plasma, has been used to obtain the spectra of multiple charged ions produced within the cathode spots. A computer calculation of the charge state distribution that evolves within the spots via stepwide ionization of ions by electron impact provides a theoretical basis fo… more

Date: August 1, 1986

Creator: Brown, I.G.; Feinberg, B. & Galvin, J.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Metal Ion Implantation for Large Scale Surface Modification

Intense energetic beams of metal ions can be produced by using a metal vapor vacuum arc as the plasma discharge from which the ion beam is formed. We have developed a number of ion sources of this kind and have built a metal ion implantation facility which can produce repetitively pulsed ion beams with mean ion energy up to several hundred key, pulsed beam current of more than an ampere, and time averaged current of several tens of milliamperes delivered onto a downstream target. We've also don… more

Date: October 1, 1992

Creator: Brown, I. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Characterization of Kevlar 49 fibers by electron paramagnetic resonance. Final report, 20 May 1981-20 June 1982. [Radicals induced by ultraviolet or fracture]

EPR was used to investigate the free radicals created in Kevlar 49 fibers by stress-induced and photo-induced macromolecular chain scissions. Mn/sup +2/ ions were identified from the EPR spectrum of frozen solutions of concentrated sulfuric acid containing Kevlar 49. Other ions present are Cu/sup +2/, and possibly Fe/sup +3/, Cr/sup +3/, and Ti/sup +3/. EPR lineshape anisotropy indicates that some of the metal ions and first coordinate spheres are oriented. The concentration of stress-induced r… more

Date: June 20, 1982

Creator: Brown, I.M. & Sandreczki, T.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Tormac confinement, theory, and experiment

Tormac is a stuffed toroidal line cusp: the magnetic field is divided into two distinct regions, i.e., an outside ''sheath'' layer where the plasma is mirror-confined on open field lines and an internal high-..beta.. region of closed nested flux surfaces. The sheath is arranged with the appropriate curvature to ensure absolute MHD stability everywhere. The bulk of the plasma is maintained on closed flux surfaces as in a typical toroidal configuration, but with enhanced MHD stability due to the … more

Date: January 1, 1978

Creator: Berk, H.L.; Brown, I.G. & Feinberg, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Advances in metal ion sources

Beams of metallic ion species can be produced by the ECR (electron cyclotron resonance) ion source and by the MEVVA (metal vapor vacuum arc) ion source. Although the ECR source is fundamentally a gaseous ion source, metal ion beams can be produced by introducing metallic feed material into the plasma discharge using a number of techniques. The ion charge states can be very high, which is a significant advantage to most applications. The MEVVA ion source, on the other hand, is specifically a met… more

Date: May 1, 1988

Creator: Brown, I.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Development of a dc, broad beam, Mevva ion source

We are developing an embodiment of metal vapor vacuum arc (Mevva) ion source which will operate dc and have very large area beam. In preliminary testing, a dc titanium ion beam was formed with a current of approximately 0.6 amperes at an extraction voltage of 9kV (about 18 keV ion energy, by virtue of the ion charge state distribution) and using an 18 cm diameter set of multi-aperture. Separately, we have tested and formed beam from a 50 cm diameter (2000 cm{sub 2}) set of grids using a pulsed … more

Date: September 1, 1991

Creator: Brown, I.G.; Dickinson, M.R.; Galvin, J.E. & MacGill, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Formation of buried epitaxial Si-Ge alloy layers in Si<100>crystal by high dose Ge ion implantation

Date: November 1, 1991

Creator: Yu, Kin Man; Brown, I.G. & Im, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Transport and acceleration of high current uranium ion beams

Measurements have been made of the transport of beams produced by the high current ion source, MEVVA, and of the injection of these beams into the GSI heavy ion RFQ linac. This configuration has provided initial tests of the MEVVA ion source in an injector environment, and of the RFQ with uranium as the accelerated species. Beam currents of 78 mA of titanium and 19 mA of uranium, at an extraction voltage of 40 kV, have been transported through a 4.7 m long beam transport channel, and up to 40 m… more

Date: October 1, 1985

Creator: Brown, I.G.; Galvin, J.E.; Keller, R.; Spaedtke, P.; Mueller, R.W & Bolle, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The SuperHILAC heavy ion intensity upgrade

A high current MEtal Vapor Vacuum Arc (MEVVA) ion source is to be installed in the third injector (Abel) at the SuperHILAC, representing the first accelerator use of this novel ion source. The MEVVA source has produced over 1 A of uranium in all charge states, with more than 100 electrical mA (emA) of U/sup 5 +/. Transport of the space-charge dominated beam through the charge-state analysis dipole will be enhanced by a 100 kV extractor voltage and neutralization by secondary electrons. In addit… more

Date: March 1, 1987

Creator: Feinberg, B. & Brown, I.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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High dose uranium ion implantation into silicon

Implantation of uranium ions into silicon to a maximum dose of 6 x 10/sup 16/ atoms/cm/sup 2/, with a maximum concentration of 6 x 10/sup 21/ atoms/cm/sup 3/, has been carried out. This concentration corresponds to 12 at. % of uranium in the silicon host material. The implanted uranium content was measured by Rutherford backscattering and confirmed by a measurement of the alpha-particle activity of the buried uranium layer. The range and straggling of the uranium, and sputtering of the silicon … more

Date: May 1, 1987

Creator: Brown, I.G.; Galvin, J.E. & Yu, K.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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LBL EBIS Program

It has been decided to increase the energy range of the LBL 88-Inch Cyclotron by constructing an advanced ion source for installation on the existing axial injection system. The type of advanced ion source chosen is the Electron Beam Ion Source. The energy range will be increased to 40 MeV/nucleon for the lighter heavy ions and with development to over 20 MeV/nucleon at mass 100. Besides the 88-inch Cyclotron, present accelerators at LBL include the SuperHILAC, with beam energy up to 8.5 MeV/A,… more

Date: May 1, 1981

Creator: Brown, I. & Feinberg, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Versatile high current metal ion implantation facility

A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multi-cathode, broad beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion-charge state multiplicity, and with a beam current of up to several amperes peak pulsed and several te… more

Date: June 1, 1991

Creator: Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X. & MacGill, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ion beam modification of the Y-Ba-Cu-O system with the MEVVA high current metal ion source

We have used high-dose metal ion implantation to 'fine tune' the composition of Y-Ba-Cu-O thin films. The films were prepared by either of two rf sputtering systems. One system uses three modified Varian S-guns capable of sputtering various metal powder targets; the other uses reactive rf magnetron sputtering from a single-mixed-oxide stoichiometric solid target. Film thickness was typically in the range 2000--5000 A. Substrates of magnesium oxide, zirconia-buffered silicon, and strontium titan… more

Date: March 1, 1989

Creator: Brown, I. G.; Rubin, M. D.; Yu, K. M.; Mutikainen, R. & Cheung, N. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department