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Grazing-incidence Cerenkov x-ray generation

Description: X-ray Cerenkov radiation can be generated by electrons incident on thin foils. For grazing incidence the Cerenkov radiation intensity can be more than a decade greater than for perpendicular incidence. Experimental results are discussed in terms of a simple formalism. 17 refs., 3 figs.
Date: August 1, 1989
Creator: Moran, Michael J.; Chang, Britton; Schneider, Marilyn B. & Maruyama, Xavier K.
Partner: UNT Libraries Government Documents Department
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Phase formation in the Pt/InP thin film system

Description: InP substrates with 40nm metal films of Pt were encapsulated in SiO{sub 2}, and isochronally annealed up to 600{degrees}C in flowing forming gas. The composition and morphology of the phases that formed were studied using x-ray diffraction, Rutherford Backscattering, and transmission electron microscopy. Results show that the Pt/InP system begins interacting at 300{degrees}C. TEM analysis of the 350{degrees}C anneal shows unreacted Pt and additional polycrystalline phases, with no observed orie… more
Date: April 1, 1989
Creator: Olson, D.A.; Yu, K.M.; Washburn, J. (Lawrence Berkeley Lab., CA (United States)) & Sands, T. (Bellcore, Red Bank, NJ (United States))
Partner: UNT Libraries Government Documents Department
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Temperature dependent effects during Ag deposition on Cu(110)

Description: The composition, structure, and morphology of ultrathin films grown by Ag deposition on Cu(110) were monitored as a function of temperature using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and medium energy ion scattering (MEIS). Aligned backscattering measurements with 150 keV He ions indicate that the Ag resides on top of the Cu and there is no significant surface compound formation. Measurements with LEED show that the Ag is initially confined to the substrate… more
Date: January 1, 1989
Creator: Taylor, T. N.; Muenchausen, R. E.; Hoffbauer, M. A.; Denier van der Gon, A. W. & van der Veen, J. F. (Los Alamos National Lab., NM (USA)
Partner: UNT Libraries Government Documents Department
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Characterization of Rh films on Ta(110)

Description: The surface and electronic structure of Rh films on Ta(110) up to several monolayers thick on Ta(110) are characterized by photoemission, Auger emission, low energy electron diffraction and low energy ion scattering. From the variation of the Rh Auger peak-to-peak intensity as a function of evaporation time, Rh/Ta(110) appears to grow in the Stranski-Krastanov mode at room temperature. However, the LEIS data show that the Rh adatoms begin to cluster on Ta(110) before growth of the monolayer is … more
Date: January 1, 1989
Creator: Jiang, L. Q.; Ruckman, M. W. & Strongin, M.
Partner: UNT Libraries Government Documents Department
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Princeton University, Plasma Physics Laboratory annual report, October 1, 1988--September 30, 1989

Description: This report contains discussions on the following topics: principal parameters achieved in experimental devices (FY89); tokamak fusion test reactor; compact ignition tokamak; princeton beta experiment- modification; current drive experiment; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma deposition and etching of thin films; theoretical studies; tokamak modeling; international thermonuclear experimental reactor; engineering department; project planning and … more
Date: January 1, 1989
Partner: UNT Libraries Government Documents Department
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High-frequency cavity applications and measurements of high-temperature superconductors

Description: A potentially important application of high-temperature superconductors will be high-frequency accelerating cavities. Currently these materials are not competitive with Nb at liquid helium temperature or with Cu at room temperature. However, available data on high-quality single crystals suggest that the relatively poor rf properties (high surface resistance and low surface magnetic field) of bulk and film specimens are due to materials properties that can be eliminated by improved processing t… more
Date: January 1, 1989
Creator: Cooke, D.W. & Gray, E.R.
Partner: UNT Libraries Government Documents Department
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Atomic oxygen-MoS/sub 2/ chemical interactions

Description: The present study shows that, at 1.5 eV O-atom translation energy, SO/sub 2/ is generated and outgases from an anhydrous MoS/sub 2/surface with an initial reactivity nearly 50% that of kapton. The reaction of atomic oxygen with MoS/sub 2/ has little or no translational energy barier; i.e., thermally generated atomic oxygen reacts as readily as that having 1.5 eV of translational energy. It is also shown that water, present in the flowing afterglow apparatus used to study thermal O-atom reactivi… more
Date: January 1, 1989
Creator: Cross, J. B.; Martin, J. A.; Pope, L. E. & Koontz, S. L.
Partner: UNT Libraries Government Documents Department
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Wear and friction of thin film high temperature oxide superconductors

Description: We have examined the sliding properties of a Nd-Fe-B magnet against a thin film YBa/sub 2/Cu/sub 3/O/sub 7/ superconductor. Pin-on-disk experiments were performed at room temperature and in normal air using a 10 mm magnetic Nd-Fe-B ball loaded to 31.22 g and a sliding speed of approximately 0.57 cm/sec. Such condition produced a steady state friction coefficient of 1.1 +- 0.3. Wear rate measurements indicated that Nd-Fe-B will wear YBa/sub 2/Cu/sub 3/O/sub 7/ at a rate 1.3 /times/ 10/sup /minus… more
Date: January 1, 1989
Creator: Nastasi, M.; Hirvonen, J.-P. & Toivanen, R.O.
Partner: UNT Libraries Government Documents Department
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The application of thick hydrogenated amorphous silicon layers to charged particle and x-ray detection

Description: We outline the characteristics of thick hydrogenated amorphous silicon layers which are optimized for the detection of charged particles, x-rays and ..gamma..-rays. Signal amplitude as a function of the linear energy transfer of various particles are given. Noise sources generated by the detector material and by the thin film electronics - a-Si:H or polysilicon proposed for pixel position sensitive detectors readout are described, and their relative amplitudes are calculated. Temperature and ne… more
Date: April 1989
Creator: Perez-Mendez, V.; Cho, G.; Fujieda, I.; Kaplan, S. N.; Qureshi, S. & Street, R. A.
Partner: UNT Libraries Government Documents Department
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The formation and analysis of thin film high temperature superconductors

Description: Thin films of high temperature superconductors have been fabricated using a variety of physical vapor deposition techniques. Recent results of HTS thin films produced by coevaporation, sputtering and laser deposition will be briefly reviewed. In addition some examples of the utility of high energy ion backscattering for the analysis of film stoichiometry will be given. 34 refs., 6 figs.
Date: January 1, 1989
Creator: Nastasi, M.; Muenchausen, R. E. & Arendt, P. N.
Partner: UNT Libraries Government Documents Department
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HREM at orthogonal projections of GaAs islands on silicon

Description: HREM studies typically examine only one projection of a structure and information in the electron beam direction is lost. In most cases, the structure in this direction is uniform and already known, but in others a second projection needs to be observed. This could involve preparing a second specimen sectioned at right angles to the first, or as described here, tilting a specimen through /plus minus/45/degree/ and observing the same volume in orthogonal projections. The specimen used here was o… more
Date: May 1, 1989
Creator: Ponce, F.A. & Hetherington, C.J.D.
Partner: UNT Libraries Government Documents Department
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Solid State Division

Description: This report contains brief discussions on work done in the Solid State Division of Oak Ridge National Laboratory. The topics covered are: Theoretical Solid State Physics; Neutron scattering; Physical properties of materials; The synthesis and characterization of materials; Ion beam and laser processing; and Structure of solids and surfaces. (LSP)
Date: August 1, 1989
Creator: Green, P. H. & Watson, D. M. (eds.)
Partner: UNT Libraries Government Documents Department
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High-energy helium backscattering for the compositional analysis of thin-film oxide-superconductors

Description: Recent experiments have demonstrated that the broad elastic-scattering resonance for 8.8 MeV helium bombardment of oxygen can be exploited to measure the oxygen content of YBaCuO thin films. A potential difficulty with such measurements is distortion of the backscattering spectrum due to resonant scattering from the substrate elements, which could prevent the accurate integration of peak areas. We have measured the elastic scattering cross sections for Sr and Ti, relative to Gd, with He ions in… more
Date: January 1, 1989
Creator: Hubbard, K. M.; Martin, J. A.; Muenchausen, R. E.; Tesmer, J. R. & Nastasi, M.
Partner: UNT Libraries Government Documents Department
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Potential applications of an electron cyclotron resonance multicusp plasma source

Description: An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and poten… more
Date: January 1, 1989
Creator: Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B. & Stirling, W.L.
Partner: UNT Libraries Government Documents Department
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Development of inherently safe and environmentally acceptable intelligent processing technologies for HTS materials

Description: The development of new processing technologies for the production, fabrication, and application of advanced materials proceeds through several complementary dimensions. The advanced materials dimension includes basic research on materials synthesis, composition, and properties; materials processing research; engineering characterization and materials applications; and product and process engineering. The health and environmental dimension includes identification of potential health and environm… more
Date: January 1, 1989
Creator: Peterson, E. J.; Wangen, L. E.; Ott, K. C.; Muenchausen, R. E. & Parkinson, W. J. (Los Alamos National Lab., NM (USA))
Partner: UNT Libraries Government Documents Department
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Oxidation of MoS/sub 2/ by thermal and hyperthermal atomic oxygen

Description: The present study shows that at 1.5 eV O-atom translational energy SO/sub 2/ is generated and out gasses from a anydrous MoS/sub 2/ surface with a reactivity comparable that of kapton. The reaction of atomic oxygen with MoS/sub 2/ has little or no translational energy barrier, i.e., thermalally generated atomic oxygen reacts as readily as that having 1.5 eV of translational energy. It has also been shown that water present in the flowing afterglow apparatus used to study thermal O-atom reactivi… more
Date: January 1, 1989
Creator: Cross, J. B.; Martin, J. A.; Pope, L. E. & Koontz, S. L.
Partner: UNT Libraries Government Documents Department
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Evaluation of atomic oxygen interaction with thin-film aluminum oxide

Description: Effects of atomic oxygen on thin-film (750/angstrom/) sputtered aluminum oxide (Al/sub 2/O/sub 3/) have been characterized. Experiments were conducted using the Los Alamos National Laboratory (LANL) O-atom facility. Diffusion of O-atoms through the Al/sub 2/O/sub 3/ thin films was observed, having an activation energy of 5.2 kcal/mole at an O-atom kinetic energy of 2 eV. Silver oxidation was used as the technique to detect penetration of O-atoms through thin-films. The Al/sub 2/O/sub 3/ films w… more
Date: January 1, 1989
Creator: Cross, J. B.; Lan, E. H.; Smith, C. A. & Arrowood, R. M.
Partner: UNT Libraries Government Documents Department
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Barriers to the nucleation of methyl groups on the diamond (111) surface

Description: Questions about the mechanism of diamond film growth by low-pressure, plasma-assisted chemical vapor deposition methods have persisted for some time now. As an attempt to explore one aspect of the problem, we examine the energetics of several adsorbed diamond (111) surfaces. The adsorbates are mixtures of methyl groups and hydrogen atoms. The model for these systems is the molecular orbital hamiltonian of Dewar and coworkers. From these calculations we find that H adsorbtion is preferred due bo… more
Date: January 1, 1989
Creator: Valone, S.M.
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

Description: 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.
Partner: UNT Libraries Government Documents Department
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Optical constants of kerogen from 0. 15 to 40. mu. m: Comparison with meteoritic organics

Description: Kerogens are dark, complex organic materials produced on the earth primarily by geologic processing of biologic materials, but kerogens have chemical and spectral similarities to some classes of highly processed extraterrestrial organic materials. Kerogen-like solids have been proposed as constituents of the very dark reddish surfaces of some asteroids and are also spectrally similar to some carbonaceous organic residues and the Iapetus dark material. Kerogen can thus serve as a useful laborato… more
Date: January 1, 1989
Creator: Khare, B.N.; Thompson, W.R.; Sagan, C. (Cornell Univ., Ithaca, NY (USA). Lab. for Planetary Studies); Arakawa, E.T.; Meisse, C. (Oak Ridge National Lab., TN (USA)) & Gilmour, I. (Chicago Univ., IL (USA))
Partner: UNT Libraries Government Documents Department
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Health, safety and environmental issues relating to cadmium usage in photovoltaic energy systems

Description: This paper discusses the current technology base and hazards associated with two promising thin-film photovoltaic cells that contain cadmium compounds -- cadmium telluride (CdTe) and copper indium diselenide (CuInSe{sub 2}). More specifically, this paper summarizes the toxicological information on cadmium (Cd) compounds; evaluates potential health, safety and environmental hazards associated with cadmium usage in the photovoltaics industry; describes regulatory requirements associated with the … more
Date: December 1, 1989
Creator: Moskowitz, P.D.; Fthenakis, V.M. (Brookhaven National Lab., Upton, NY (USA)) & Zweibel, K. (Solar Energy Research Inst., Golden, CO (USA))
Partner: UNT Libraries Government Documents Department
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High Index of Refraction Films for Dielectric Mirrors Prepared by Metal-Organic Chemical Vapor Deposition

Description: A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs.
Date: January 1989
Creator: Brusasco, Raymond M.
Partner: UNT Libraries Government Documents Department
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Influence of ion irradiated SrTiO/sub 3/ on the properties of thin film oxide superconductors

Description: The quality of high temperature superconducting thin films is dependent on the structure of the substrate used. The present work examines the effects of radiation damaged SrTiO/sub 3/ substrates on the properties of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/ thin film superconductors. Prior to film deposition, single crystal SrTiO/sub 3/ substrates were cooled to 77 K and irradiated with 400 keV Ne ions to doses of 1 /times/ 10/sup 15/ and 1 /times/ 10/sup 16/ ions/cm/sup 2/. Following deposition the f… more
Date: January 1, 1989
Creator: Bordes, N.; Cohen, M.; Nastasi, M.; Rollett, A.D. & Maggiore, C.J.
Partner: UNT Libraries Government Documents Department
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Studies of the Ag/Cu(110) bimetallic interface using optical second-harmonic generation

Description: Optical second harmonic generation (SHG) has recently been shown to be a sensitive, real-time, in situ probe for studying interfaces under many different environments. With regard to atomically clean well-characterized surfaces, SHG has been shown to be sensitive to submonolayer coverages of adsorbates, the structural symmetry or molecular arrangement on the surface, and the surface reordering observed during laser induced melting and recrystallization. Previous SHG studies of bimetallic system… more
Date: January 1, 1989
Creator: Muenchausen, R. E.; Hoffbauer, M. A. & Taylor, T. N.
Partner: UNT Libraries Government Documents Department
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