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Defects in metal crystals. Progress report, May 1, 1973--April 30, 1974

Description: Progress was made in the following areas: FIM (field ion microscopy) studies of defects in W irradiated with W ions or electrons; FIM studies of Au irradiated with Au or Xe ions; FIM and electrical resistivity study of vacancy defects in quenched W; FIM studies of dilute Pt alloys; measurement of the range of focused replacement sequences in Au; investigation of grain boundary strtucture (using Au); FIM observation of dissociated screw dislocations in Mo; calculation of properties of point defe… more
Date: January 1, 1974
Creator: Balluffi, R.W. & Seidman, D.N.
Partner: UNT Libraries Government Documents Department
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Operation of TFTR neutral beams with heavy ions

Description: High Z neutral atoms have been injected into TFTR plasmas in an attempt to enhance plasma confinement through modification of the edge electric field. TFTR ion sources have extracted 9 A of 62 keV Ne{sup +} for up to 0.2 s during injection into deuterium plasmas, and for 0.5 s during conditioning pulses. Approximately 400 kW of Ne{sup 0} have been injected from each of two ion sources. Operation was at full bending magnet current, with the Ne{sup +} barely contained on the ion dump. Beamline de… more
Date: July 1, 1991
Creator: Kamperschroer, J. H.; Stevenson, T. N.; Wright, K. E.; Dudek, L. E.; Grisham, L. R.; Newman, R. A. et al.
Partner: UNT Libraries Government Documents Department
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Radiochemical study of the reactions of heavy ions with gold

Description: Thick gold foils have been bombarded with heavy-ion projectiles at energies above the Coulomb barrier. The radioactive products were identified and their yields measured using gamma-ray spectrometry and an extensive series of computer programs developed for the data analysis. The total mass-yield distribution was extracted from the data using charge-dispersion curves inferred from the experimental results. One observes a change in the mass-yield distributions corresponding to primarily fusion-f… more
Date: July 1, 1977
Creator: Binder, I.
Partner: UNT Libraries Government Documents Department
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X-ray transitions in highly charged neonlike ions

Description: Wavelength measurements of n=3 to n=2 transitions in neonlike Xe/sup 44 +/, La/sup 47 +/, Nd/sup 50 +/, and Eu/sup 53 +/ have been made using a high-resolution Bragg-crystal spectrometer on the Princeton Large Torus tokamak. The measurements cover the wavelength regions 2.00 to 3.00 (angstrom) and include the electric dipole, and the electric and magnetic quadrupole transitions. The measured wavelengths are compared to energy levels obtained from a multiconfigurational Dirac-Fock calculation. S… more
Date: November 1, 1987
Creator: Beiersdorfer, P.; von Gjoeler, S.; Bitter, M.; Hinnov, E.; Bell, R.; Bernabei, S. et al.
Partner: UNT Libraries Government Documents Department
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Heavy ion fusion program. Half-year report, October 1978--March 1979

Description: Research activities in heavy ion fusion from October 1978 to March 1979 are reported. Primary areas covered include: induction linac systems; R.F. linac/storage ring systems; theory; and heavy ion fusion notes. (GHT)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department
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Heavy Ion Fusion Program. Year-end report, October 1978-September 1979

Description: The more significant activities and results reported for this year are: (1) Commissioning, in January 1979, of a large-area Cs/sup +1/ ion source of 1.2 amperes at 500 kV. (2) Commissioning, in July 1979, of the first drift-tube of the three drift-tube accelerator. (3) Acceleration, in January 1979, of a high-brightness, 40 milliampere Xe/sup +1/ beam through a Cockcroft-Walton column to 500 kV and confirmation of satisfactory emittance and charge distribution. (4) Development of a conceptual d… more
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department
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Bremsstrahlung from high Z impurities in hot plasmas

Description: This is a study of the effect of core electron and plasma screening on Bremsstrahlung from high-Z impurities in hot plasmas. 3 refs., 7 figs., 1 tab.
Date: May 9, 1988
Creator: DeWitt, H.; Rogers, F. & Iglesias, C.
Partner: UNT Libraries Government Documents Department
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Calculation of the Transfer Matrix T in Six Dimensions for an rf-Deflector Element

Description: One possible element for funneling two beams together is a deflector with a constant or time-varying electric-field strength. With such an element, arbitrary beams can be brought together and maintained on the axis, if the appropriate combination of deflector parameters is chosen. A parallel beam can be handled only with a time-varying voltage of the deflector. The six-dimensional transfer matrices are calculated for constant or time-varying fields; all the results are correct in first-order ap… more
Date: January 1, 1981
Creator: Bongardt, K.
Partner: UNT Libraries Government Documents Department
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High-current pulsed ion source for metallic ions

Description: A new sputter-ion PIG source and magnet system, optimized for intermediate charge states, q/A of 0.02 to 0.03, is described. This source will be used with the new Wideroe-based injector for the SuperHILAC. Pulsed electrical currents of several emA of heavy metal ions have been produced in a normalized emittance area of .05..pi.. cm-mr. The source system is comprised of two electrically separate anode chambers, one in operation and one spare, which can be selected by remote control. The entire s… more
Date: March 1, 1981
Creator: Gavin, B.; Abbott, S.; MacGill, R.; Sorensen, R.; Staples, J. & Thatcher, R.
Partner: UNT Libraries Government Documents Department
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Transmission sputtering of gold thin-films by low-energy (< 1 keV) xenon ions: I. The system and the measurement

Description: A novel system for direct measurement of the transmission sputtering yields of ion-irradiated thin films is described. The system was specifically designed for the study of the transmission sputtering caused by low energy (<1 keV) xenon ions. The xenon ion-beam employed was first mass anayzed in a specially constructed crossed magnetic and electric-field mass spectrometer; this analyzer eliminated all energetic neutral and singly-charged ions of mass less than 40 amu; it is also expected that l… more
Date: January 1, 1978
Creator: Ayrault, G. & Seidman, D.N.
Partner: UNT Libraries Government Documents Department
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Temperature dependence of ion-beam-induced amorphization in {beta}-SiC

Description: The ion-beam-induced crystalline-to-amorphous transition in monolithic {beta}-SIC has been studied as a function of irradiation temperature using the HVEM-Tandem Facility at Argonne National Laboratory. Specimens were irradiated with 1.5 MeV Xe{sup +} ions over the temperature range from 40 to 550 K, and the evolution of the amorphous state was followed in situ using the HVEM. At 40 K, the displacement dose for complete amorphization in {beta}-SIC is 0.34 dpa and increases with temperature in t… more
Date: February 1, 1995
Creator: Weber, W. J. & Wang, L. M.
Partner: UNT Libraries Government Documents Department
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The interactions of high-energy, highly charged Xe ions with buckyballs

Description: Ionization and fragmentation have been measured for C{sub 60} molecules bombarded by highly charged (up to 35+) xenon ions with energies ranging up to 625 MeV. The observed mass distribution of positively charged fragments is explained in terms of a theoretical model indicating that the total interaction cross section contains roughly equal contributions from (a) excitation of the giant plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecul… more
Date: December 31, 1994
Creator: Ali, R.; Berry, H. G. & Cheng, S.
Partner: UNT Libraries Government Documents Department
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Spectra of highly ionized atoms of tokamak interest

Description: The general nature of the change in energy level structures along an isoelectronic sequence is reviewed, with particular emphasis on relativistic effects and changes in coupling conditions. The accuracy of computed wavelengths is checked by comparison with experimental data on inner-shell (x-ray) transitions in singly ionized atoms. Relativistic effects can be extremely important for ..delta..n = 0 transitions, but are taken into account fairly accurately by the approximate relativistic methods… more
Date: January 1, 1977
Creator: Cowan, R. D.
Partner: UNT Libraries Government Documents Department
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Technical progress report, October 1, 1974--September 30, 1975. [Summaries of research activities at Wisconsin Univ]

Description: Six areas of research are reported: I. Equilibrium fractions of D/sup -/ ions when D/sup +/, D/sub 2//sup +/ or D/sub 3//sup +/ ions are incident on a Cs vapor target. II. Charge exchange collisions when hydrogen and deuterium ions are incident on a Cs vapor target, in which the total charge exchange cross sections sigma/sub +/sub 0// for H/sup +/, H/sub 2//sup +/, D/sup +/, D/sub 2//sup +/, are reported. III. Charge exchange cross sections with rare gas ions incident on a Cs vapor target for H… more
Date: January 1, 1976
Partner: UNT Libraries Government Documents Department
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[Structure and electronic properties of defects at nonlattice matched III-V semiconductor interfaces]. Progress report, 1989--90

Description: Research focused on control of misfit dislocations in strained epitaxial layers of GaAs through prepatterning of the substrate. Patterning and etching trenches into GaAs substrates before epitaxial growth results in nonplanar wafer surface, which makes device fabrication more difficult. Selective ion damaging the substrate prior to growth was investigated. The question of whether the overlayer must or must not be discontinuous was addressed. The third research direction was to extend results fr… more
Date: December 31, 1990
Creator: Ast, D. G.
Partner: UNT Libraries Government Documents Department
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Parametric Investigation of Miniaturized Cylindrical and Annular Hall Thrusters

Description: Conventional annular Hall thrusters become inefficient when scaled to low power. An alternative approach, a 2.6-cm miniaturized cylindrical Hall thruster with a cusp-type magnetic field distribution, was developed and studied. Its performance was compared to that of a conventional annular thruster of the same dimensions. The cylindrical thruster exhibits discharge characteristics similar to those of the annular thruster, but it has a much higher propellant ionization efficiency. Significantly, … more
Date: September 12, 2002
Creator: Smirnov, A.; Raitses, Y. & Fisch, N. J.
Partner: UNT Libraries Government Documents Department
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Effect of temperature and recoil-energy spectra on irradiation-induced amorphization in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2}

Description: Single crystals of Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} have been irradiated with different ions/energies in an in situ study of the effects of temperature and recoil-energy spectra on irradiation-induced amorphization. The dose for complete amorphization increases with temperature in two stages. The low-temperature stage (below 250 K) has an activation energy of 0.01 {plus_minus} 0.003 eV and is believed to be associated with simultaneous close-pair recombination. The high-temperature… more
Date: September 1, 1993
Creator: Weber, W. J. & Wang, L. M.
Partner: UNT Libraries Government Documents Department
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Theoretical research in physics of highly ionized atoms. Final report, March 1, 1975--June 30, 1976. [Preliminary study, transition probabilities, model potential theory, Dirac and Schroedinger equations]

Description: Results of a preliminary study of the use of a model potential approach to the calculation of energy levels and radiative transition probabilities for highly ionized heavy atoms are reported. The calculations were carried out for eight ions in the sodium isoelectronic sequence from Mg II through W LXIV. The technique used involved the solution of the Dirac equation for the single outer valence electron, with a model central potential containing two disposable parameters affecting the potential … more
Date: January 1, 1976
Creator: Bardsley, J N & Norcross, D W
Partner: UNT Libraries Government Documents Department
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Spectroscopy at the high-energy electron beam ion trap (Super EBIT)

Description: The following progress report presents some of the x-ray measurements performed during the last year on the Livermore SuperEBIT facility. The measurements include: direct observation of the spontaneous emission of the hyperfine transition in ground state hydrogenlike holmium, {sup 165}Ho{sup 66{plus}}; measurements of the n {equals} 2 {r_arrow} 2 transition energies in neonlike thorium, Th{sup 80{plus}}, through lithiumlike thorium, Th{sup 87{plus}}, testing the predictions of quantum electrody… more
Date: July 10, 1996
Creator: Widmann, K.; Beiersdorfer, P. & Crespo Lopez-Urrutia, J.R.
Partner: UNT Libraries Government Documents Department
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Plastic flow in fcc metals induced by single-ion impacts

Description: Irradiation of Au and Pb foils with Xe ions at temperatures between 30 and 450 K has been monitored using in-situ transmission electron microscopy. Single ion impacts give rise to surface craters on the irradiated surface with sizes as large as 12 nm. Approximately 2--5% of impinging ions produce craters on Au while only about 0.6% produce craters on Pb. Larger craters on Au frequently have expelled material associated with them. Temporal details of crater formation and annihilation has been re… more
Date: September 1997
Creator: Birtcher, R. C. & Donnelly, S. E.
Partner: UNT Libraries Government Documents Department
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Irradiation-Induced Phase Transformations. Final Report, July 1, 1995--June 30, 1997

Description: During the course of this two year program, the authors attention focused largely on the synthesis, structure and properties of group IV semiconductor nanocrystals. They also drew to a close the investigations of defects in amorphous silicon. Work on control of nucleation in amorphous silicon and germanium is ongoing, and has taken important new directions at the interface between basic and applied research under DOE Office of Energy Efficiency support via a subcontract from the National Renewa… more
Date: August 1, 1998
Creator: Atwater, H. A.
Partner: UNT Libraries Government Documents Department
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Measurement of charge exchange cross sections for highly charged xenon and thorium ions with molecular hydrogen in a Penning Ion Trap

Description: Highly charged xenon (35+ to 46+) and thorium (72+ to 79+) ions were produced in an Electron Beam Ion Trap (EBIT). The ions were extracted from EBIT in a short pulse. Ions of one charge state were selected using an electromagnet. The ions were recaptured at low energy in a cryogenic Penning trap (RETRAP). As the ions captured electrons from molecular hydrogen, populations of the various charge states were obtained by measuring the image currents induced by the ions on the electrodes of the trap… more
Date: December 1, 1995
Creator: Weinberg, G.M.
Partner: UNT Libraries Government Documents Department
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Metal-ceramic composites for hostile environment applications

Description: The authors have developed a new metal-ceramic composite made from vanadium metal (V) and a non-stoichiometric magnesio-aluminate spinel ceramic. Three vanadium-spinel compositions, 40-60, 50-50, and 60-40 (by volume) were prepared by hot pressing mixtures of commercial powders. The properties of these composites were determined by measuring coefficient of thermal expansion, hardness, elastic constants, and fracture toughness. Radiation damage studies were performed on 50-50 vanadium-spinel com… more
Date: July 1, 1996
Creator: Uestuendag, E.; Sickafus, K.; He, Y.; Schwarz, R. B.; Panda, P. C. & Raj, R.
Partner: UNT Libraries Government Documents Department
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