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Gold Beam Losses at the AGS Booster Injection.

Description: Gold beam injection efficiency decreases in proportional to the beam loss in the AGS Booster. A close look shows that large number of electrons, ions, and neutral particles are created when the gold beam scrapes wall. To investigate the neutral particle production due to the beam loss, local vacuum measurement was made during the 1998 run. It shows that the pressure created by the Booster Au{sup 31+} beam loss at injection has a 35 ms decay time constant. The beam loss created pressure bump in … more
Date: March 29, 1999
Creator: Zhang, S. Y. & Ahrens, L. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Adhesion, Deformation and Friction for Self-Assembled Monolayers on Au and Si Surfaces

Description: Using Interracial Force Microscopy (IFM), we investigated the tribological behavior of hexadecanethiol monolayer on Au and films of octadecyltrichlorosilane (ODTS), perfluorodecyltrichlorosilane (PFTS) and dodecane on Si. We observe a strong correlation between hysteresis in a compression cycle (measured via nanoindentation) and friction. Additionally, we suggest that the amount of hysteresis and friction in each film is related to its detailed molecular structure, especially the degree of mole… more
Date: July 7, 1999
Creator: Houston, J. E.; Hsung, R. P.; Kiely, J. D.; Mulder, J. A. & Zhu, X. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Structure-Dependent Viscoelastic Properties of C(9)-Alkanethiol Monolayers

Description: Quartz crystal microbalance techniques and in situ spectroscopic ellipsometry are used to probe the structure-dependent intrinsic viscoelastic properties of self-assembled CH{sub 3}(CH{sub 2}){sub 8}SH alkanethiol monolayer adsorbed from the gas phase onto Au(111)-textured substrates. Physisorbed molecules, mixed chemisorbed-fluid/solid phases and solid-phase domain boundaries make sequentially dominant contributions to the measured energy dissipation in the growing monolayer. Deviations from L… more
Date: August 10, 1999
Creator: Mayer, Thomas M.; Michalske, Terry A. & Shinn, Neal D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Direct flow in 10.8 GeV/nucleon Au+Au collisions measured in experiment E917 at the AGS.

Description: Analysis of directed flow observable for protons and pions from Au+Au collisions at 10.8 GeV/nucleon from experiment E917 at the AGS is presented. Using a Fourier series expansion, the first Fourier component, {nu}{sub 1},was extracted as a function of rapidity for mid-central collisions (17-24%). Clear evidence for positive directed flow is found in the proton data, and a weak, possibly negative directed flow signal is observed for {pi}{sup +} and {pi}{sup {minus}}.
Date: May 19, 1999
Creator: Back, B. B.; Betts, R. R.; Britt, H. C.; Chang, J.; Chang, W. C.; Gillitzer, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Production of {phi} meson in Au+Au collisions at 11.7 A GeV/c.

Description: First Measurement of {phi} meson production in Au+Au collisions has been conducted by E917 at BNL-AGS via selecting events with identified K{sup +}K{sup {minus}} pairs. Preliminary results on the invariant mass spectra of K{sup +}K{sup {minus}} pairs and the m{sub T} spectra are presented. Also, the inverse slope T, dN/dy, the ratio of {phi}/K{sup {minus}}, ratio of {phi}/K{sup +}K{sup {minus}} and their centrality dependences are extracted in a rapidity range of y = 0.9-1.4. Indications on the… more
Date: June 29, 1999
Creator: Back, B. B.; Betts, R. R.; Chang, J.; Chang, W. C.; Chi, C. Y.; Collaboration, E917 et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observations of Non-Close-Packed Arrangements in Multilayers of Passivated Gold Clusters

Description: The stacking of second and third layers of supercrystals of self-assembled passivated gold nanoparticles has been investigated using transmission electron microscopy. We report for the first time nanoparticles occupying the twofold saddle site in the third layer.
Date: October 5, 1999
Creator: AINDOW, M.; Brown, P.; Kiely, C. J.; Wellner, A. & Wilcoxon, Jess P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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In situ spectroscopic ellipsometry as a surface sensitive tool to probe thin film growth.

Description: Sputtered thin film and multilayer x-ray mirrors are made routinely at the Advanced Photon Source (APS) for the APS users. Precise film growth control and characterization are very critical in fabricating high-quality x-ray mirrors. Film thickness calibrations are carried out using in situ and ex situ spectroscopic ellipsometry, interferometry, and x-ray scattering. To better understand the growth and optical properties of different thin film systems, we have carried out a systematic study of s… more
Date: February 19, 1999
Creator: Liu, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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SOME PHYSICAL AND ENGINEERING ASPECTS OF HIGH CURRENT EBIS.

Description: Some applications of an Electron Beam Ion Source (EBIS) require intensities of highly charged ions significantly greater than those which have been achieved in present EBIS sources. For example, the ion source for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) must be capable of generating 3x10{sup 9} ions of Au{sup 35+} or 2 x 10{sup 9} ions of U{sup 45+} per pulse [1]. In this case, if the fraction of ions of interest is 20% of the total ion space charge, t… more
Date: May 10, 1999
Creator: Pikin, A.
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
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Atom-by-Atom and Concerted Hopping of Adatom Pairs on an Open Metal Surface

Description: Atom-by-atom and concerted hopping of ad-dimers on the open (100) surface of fcc metals are studied by means of density-functional calculations. The adatom interaction is relatively short-ranged, and beyond next-nearest neighbors ad-dimers are effectively dissociated. Diffusion takes place by a simple shearing process, favored because it maximizes adatom coordination at the transition state This holds for Al, Au, and Rh, and is likely a general result because geometrical arguments dominate over… more
Date: August 25, 1999
Creator: Bogicevic, A.; Ovesson, S.; Lundqvist, B. I. & Jennison, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Results from experiment E917 for Au + Au collisions at the AGS.

Description: The effects of baryon stopping and its resulting energy deposition on the dynamics of Au + Au collisions at 6, 8 and 10.8 GeV/nucleon are explored with recent results from the AGS experiment E917. Current analyses of stopping, collective flow signals and HBT parameters are presented. Strangeness and anti-baryon production is examined using the yields of anti-lambdas and anti-protons.
Date: August 4, 1999
Creator: Back, B. B.; Betts, R. R.; Chang, J.; Chang, W. C.; Collaboration, E917; Gillitzer, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Strangeness production in Au+Au collisions at the AGS: recent results from E917.

Description: Strangeness production in Au+Au collisions has been measured via the yields of K{sup +} , K{sup {minus}} at 6, 8 AGeV and of {bar {Lambda}} at 10.8 AGeV beam kinetic energy in experiment E917. By varying the collision centrally and beam energy, a systematic search for indications of new phenomena and in-medium effects under high baryon density is undertaken.
Date: March 30, 1999
Creator: Chang, W.-C.; Back, B. B.; Betts, R. R.; Britt, H. C.; Chang, W. C.; Gillitzer, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HIGH PT PHYSICS WITH THE STAR EXPERIMENT AT RHIC.

Description: The STAR experiment at RHIC is a TPC-based, general purpose detector designed to obtain charged particle spectra, with an emphasis on hadrons over a large phase space. An electromagnetic calorimeter provides measurement of e's, {gamma}'s, {pi}{sup 0}'s and jets. Data-taking with Au + Au collisions at {radical}5 = 200 GeV/c{sup 2} begins in Fall 1999. The STAR experiment's investigation of techniques and signals using hard probes to study the high energy-density matter at RHIC and to search for … more
Date: March 21, 1999
Creator: TURNER,K. FOR THE STAR COLLABORATION
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Turn-by-Turn Analysis of Proton and Gold Beams at Injection in the AGS Booster.

Description: In this paper we describe the latest version of a program we have used for several years to acquire and analyze turn-by-turn data from pick-up electrodes in the AGS Booster during injection. The program determines several parameters of the injected beam including the tunes and the position and angle of the incoming beam. Examples are given for both proton and gold injection.
Date: March 29, 1999
Creator: Gardner, C.; Ahrens, L. & Williams, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Injection of Gold Ions in the AGS Booster With Linear Coupling.

Description: Linear Coupling, introduced by skew quadrupoles, has been used for several years to enhance the multi-turn injection efficiency of gold and other heavy ions in the AGS Booster. In this paper we describe our latest measurements of the injection process and compare with models.
Date: March 29, 1999
Creator: Gardne, C.; Ahrens, L.; Roser, T. & Zeno, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Models and Analysis of Wire Explosions Using TRAC II Simulations

Description: In order to understand the dynamics of Z-pinch imposions of thin wires in pulse-power accelerators, it is necessary to understand the physical process by which the initially solid wires are converted into plasma by rising current. For this purpose, we model wire explosions using TRAC II, a two-dimensional MHD code, in three distinct cases: pure tungsten, impure tungsten, and gold-plated tungsten. We compare our results--overall picture of the process, corona linear density, corona mass, and cor… more
Date: September 10, 1999
Creator: Pekker, A. & Reisman, D.B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fast Resistive Bolometry

Description: Resistive bolometry is an accurate, robust, spectrally broadband technique for measuring absolute x-ray fluence and flux. Bolometry is an independent technique for x-ray measurements that is based on a different set of physical properties than other diagnostics such as x-ray diodes, photoconducting detectors, and P-I-N diodes. Bolometers use the temperature-driven change in element resistivity to determine the total deposited energy. The calibration of such a device is based on fundamental mate… more
Date: February 1, 1999
Creator: Deeney, C.; Fehl, D. L.; Hanson, D. L.; Keltner, N. R.; McGurn, J. S.; McKenney, J. L. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Short-range order types in binary alloys: A reflection of coherent phase stability

Description: The short-range order (SRO) present in disordered solid solutions is classified according to three characteristic system-dependent energies: (1) formation enthalpies of ordered compounds, (2) enthalpies of mixing of disordered alloys, and (3) the energy of coherent phase separation, (the composition-weighted energy of the constituents each constrained to maintain a common lattice constant along an A/B interface). These energies are all compared against a common reference, the energy of incohere… more
Date: November 23, 1999
Creator: Wolverton, W.; Ozolins, V. & Zunger, Alex
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The RHIC Beam Abort Kicker System

Description: THE ENERGY STORED IN THE RHIC BEAM IS ABOUT 200 KJ PER RING AT DESIGN ENERGY AND INTENSITY. TO PREVENT QUENCHING OF THE SUPERCONDUCTING MAGNETS OR MATERIAL DAMAGE, THE BEAM WILL BE SAFELY DISPOSED OF BY AN INTERNAL BEAM ABORT SYSTEM, WHICH INCLUDES THE KICKER MAGNETS, THE PULSED POWER SUPPLIES, AND THE DUMP ABSORBER. DISPOSAL OF HEAVY IONS, SUCH AS GOLD, IMPOSES DESIGN CONSTRAINTS MORE SEVERE THAN THOSE FOR PROTON BEAMS OF EQUAL INTENSITY. IN ORDER TO MINIMIZE THE THERMAL SHOCK IN THE CARBON-FI… more
Date: March 29, 1999
Creator: Hahn, H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Tensile Creep Properties of the 50Au-50Cu Braze Alloy

Description: The 50Au-50CU (wt.%) alloy is a solid-solution strengthened braze alloy used extensively in conventional, hermetic metal/ceramic brazing applications where low vapor pressure is a requirement. Typical metal/ceramic base materials would be Kovar<sup>TM</sup> alloy and metallized and Ni-plated 94% alumina ceramic. The elevated temperature mechanical properties are important for permitting FEA evaluation of residual stresses in metal/ceramic brazes given specific geometries and braze cooldown prof… more
Date: May 28, 1999
Creator: Stephens, J.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Growth of a Au-Ni-Sn intermetallic compound on the solder-substrate interface after aging

Description: Au/Ni metallization has become increasingly common in microelectronic packaging when Cu pads are joined with Pb-Sn solder. The outermost Au layer serves to protect the pad from corrosion and oxidation and the Ni layer provides a diffusion barrier to inhibit detrimental growth of Cu-Sn intermetallics. As a result of reflowing eutectic Pb-Sn on top of Au/Ni metallization, the as-solidified joints have AuSn{sub 4} precipitates distributed throughout the bulk of the solder joint, and Ni{sub 3}Sn{su… more
Date: December 16, 1999
Creator: Minor, Andrew M. & Morris, J. W., Jr.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Investigation of Rare Particle Production in High Energy Nuclear Collisions

Description: Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu coll… more
Date: September 2, 1999
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrochemical and scanning probe microscopic characterization of spontaneously adsorbed organothiolate monolayers at gold

Description: This dissertation presented several results which add to the general knowledge base regarding organothiolates monolayer spontaneously adsorbed at gold films. Common to the body of this work is the use of voltammetric reductive resorption and variants of scanning probe microscopy to gain insight into the nature of the monolayer formation process as well as the resulting interface. The most significant result from this work is the success of using friction force microscopy to discriminate the end… more
Date: December 10, 1999
Creator: Wong, Sze-Shun Season
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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