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A 20mK temperature sensor

Description: We are developing a 20mK temperature sensor made of neutron transmutation doped (NTD) germanium for use as a phonon detector in a dark matter search. We find that NTD germanium thermistors around 20mK have resistances which are a strong function of temperature, and have sufficient sensitivity to eventually reach a base line rms energy fluctuation of 6eV at 25mK. Further work is needed to understand the extreme sensitivity of the thermistors to bias power. 13 refs., 18 figs.
Date: November 1987
Creator: Wang, N.; Sadoulet, B.; Shutt, T.; Beeman, J.; Haller, E.E.; Lange, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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235U and TRU Holdup Measurements on the 321-M Sawbenches

Description: The Analytical Development Section of Savannah River Technology Center (SRTC) was requested by the Facilities Disposition Projects (FDP) to determine the holdup of enriched uranium in the 321-M facility as part of an overall deactivation project of the facility. The 321-M facility was used to fabricate enriched uranium fuel assemblies, lithium-aluminum target tubes, neptunium assemblies, and miscellaneous components for the production reactors. The results of the holdup assays are essential for… more
Date: July 2, 2004
Creator: Dewberry, R
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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48Ti(n,xnypz ag) reactions for neutron energies up to 250 MeV

Description: Cross section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy on a {sup 48}Ti sample. Partial {gamma}-ray cross sections for transitions in {sup 45--48}Ti, {sup 44--48}Sc, {sup 42--45}Ca, {sup 41--44}K, and {sup 41--42}Ar have been determined. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction {gamma} rays were detected with the large-scale Comp… more
Date: October 11, 2004
Creator: Dashdorj, D.; Garrett, P. E.; Becker, J. A.; Bernstein, L. A.; Cooper, J. R.; Devlin, M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ab initio calculation of ground- and excited-state properties of surfaces. [Ge(111):As and Si(111):As]

Description: A new approach for surface studies using the density functional formalism for structural determination and a first principles many-body theory for the quasiparticle surface state energies is discussed. The many-body calculation involves the evaluation of the electron self-energy operator including both local fields and dynamical screening effects. Results for the Ge(111):As and Si(111):As surface are in excellent agreement with recent angle-resolved photoemission data and show a substantially l… more
Date: April 1, 1987
Creator: Louie, S.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ab initio study of the epitaxial growth of Ge on Si(100) surface

Description: We identify the binding sites for adsorption of a single Ge atom on the Si(100) surface using ab initio total energy calculations. The calculated diffusion barriers are in excellent agreement with experimental estimates. Using a large supercell we resolve the controversy regarding the binding geometry and migration path for the adatom, and investigate the influence of the adatom on the buckling of Si dimers. The adatom induces a buckling defect that is frequently observed using scanning tunneli… more
Date: November 1, 1993
Creator: Milman, V.; Pennycook, S. J.; Jesson, D. E.; Payne, M. C. & Stich, I.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Ability of the United States Federal Radiological Monitoring and Assessment Center to Collect and Disseminate Environmental Measurements during Radiological Emergencies

Description: The Federal Radiological Monitoring and Assessment Center (FRMAC) is the United States’ response organization for radiological emergencies. The FRMAC is structured as an operations center and employs the combined resources of several federal agencies to respond to any disaster resulting in the release of radioactivity. The mission of the FRMAC is to support state and local authorities in the gathering of environmental data using an array of survey equipment ranging from alpha probes, beta/gamma… more
Date: April 30, 2007
Creator: Essex, Craig Marianno and James
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Absorbance and Photoluminescence of Si, Ge, and MoS2 Nanoparticles Studied by Liquid Chromatography

Description: The authors have successfully synthesized highly crystalline, size-selected indirect band-gap nanocrystals (NC) of Si, Ge and MoS{sub 2} in the size range 2-10 nm in inverse micelles and studied their optical absorption and photoluminescence (PL) properties using liquid chromatography. Room temperature, visible PL from these nanocrystals was demonstrated in the range 700-350 nm (1.8-3.5 eV). their experimental results are interpreted in terms of the corresponding electronic structure of the bul… more
Date: July 12, 1999
Creator: Provencio, P. P.; Samara, G. A. & Wilcoxon, J. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Acoustic absorption by the electron-hole liquid in germanium

Description: The absorption of ultrasonic acoustic waves by the electron-hole liquid that may be created in germanium at liquid helium temperatures by intense optical excitation was studied. This is a degenerate compensated Fermi liquid that exhibits the behavior of both classical dynamics in a force field, and quantum phenomena in a magnetic field. Results of theoretical and experimental studies of the interaction of the mobile liquid with a travelling acoustic wave force field, the attenuation of the wave… more
Date: November 1, 1977
Creator: Hansen, A.D.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Acquisition of powder diffraction data with synchrotron radiation

Description: During the past year, a dedicated triple-axis powder diffractometer has been in routine operation at the Brookhaven National Synchrotron Light Source as a user-oriented facility. The diffractometer is designed to allow easy interchange between energy-dispersive and monochromatic beam experiments. In the latter mode of operation, high resolution data have been collected for a variety of samples with the use of the crystal-analyzer technique, and in several cases these data sets have been used su… more
Date: January 1, 1987
Creator: Cox, D. E.; Toby, B. H. & Eddy, M. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Adaptive scanning probe microscopies

Description: This work is comprised of two major sections. In the first section the authors develop multivariate image classification techniques to distinguish and identify surface electronic species directly from multiple-bias scanning tunneling microscope (STM) images. Multiple measurements at each site are used to distinguish and categorize inequivalent electronic or atomic species on the surface via a computerized classification algorithm. Then, comparison with theory or other suitably chosen experiment… more
Date: February 1, 1997
Creator: Swartzentruber, B.S.; Bouchard, A.M. & Osbourn, G.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Advanced far infrared detector and double donor studies in Ge

Description: This has application to astronomy and astrophysics. Selenium in Ge has been studied with a doping technique which limits complex formation. Only one ionization level has been found to correspond to selenium, which presumably occupies a substitutional site. This level is extremely unstable and its concentration decreases after annealing at 400C. Future work is planned to anneal the fast neutron damage before much selenium has formed in the {sup 74/76}Ge samples. It is expected that the observed … more
Date: December 1, 1994
Creator: Olsen, C.S.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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AlGaAs/InGaAlP tunnel junctions for multijunction solar cells

Description: Optimization of GaInP{sub 2}/GaAs dual and GaInP{sub 2}/GaAs/Ge triple junction cells, and development of future generation monolithic multi-junction cells will involve the development of suitable high bandgap tunnel junctions. There are three criteria that a tunnel junction must meet. First, the resistance of the junction must be kept low enough so that the series resistance of the overall device is not increased. For AMO, 1 sun operation, the tunnel junction resistance should be below 5 x 10{… more
Date: May 16, 2000
Creator: Sharps, P. R.; Li, N. Y.; Hills, J. S.; Hou, H.; Chang, Ping-Chih & Baca, Albert G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Alternative Gate Dielectrics on Semiconductors for MOSFET Device Applications

Description: We have investigated the synthesis and properties of deposited oxides on Si and Ge for use as alternative gate dielectrics in MOSFET applications. The capacitance and leakage current behavior of polycrystalline Y{sub 2}O{sub 3} films synthesized by pulsed-laser deposition is reported. In addition, we also discuss the growth of epitaxial oxide structures. In particular, we have investigated the use of silicide termination for oxide growth on (001) Si using laser-molecular beam epitaxy. In additi… more
Date: December 6, 1999
Creator: Norton, D. P.; Budai, J. D.; Chisholm, M. F.; Pennycook, S. J.; McKee, R.; Walker, F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Amorphous germanium as an electron or hole blocking contact on high-purity germanium detectors

Description: Experiments were performed in an attempt to make thin n/sup +/ contacts on high-purity germanium by the solid phase/sup 1)/ epitaxial regrowth of arsenic doped amorphous germanium. After cleaning the crystal surface with argon sputtering and trying many combinations of layers, it was not found possible to induce recrystallization below 400/sup 0/C. However, it was found that simple thermally evaporated amorphous Ge made fairly good electron or hole blocking contacts. Excellent spectrometers hav… more
Date: October 1, 1976
Creator: Hansen, William L. & Haller, Eugene E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Amplified reflection via degenerate four-wave mixing in a laser induced free carrier plasma in germanium

Description: The first observation of amplified reflection at CO/sub 2/ laser wavelengths via degenerate four-wave mixing in an optically induced free-carrier plasma in germanium is presented. Reflectivities of over 100% are reported in both n-type and p-type Ge. A model is presented which predicts both the magnitude and the I/sup 11/ intensity dependence of the reflectivity from the free carrier plasma density. This density is determined experimentally by time-resolving the incident and transmitted signals… more
Date: January 1, 1981
Creator: Watkins, D. E.; Phipps, C. R. Jr. & Thomas, S. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analog Readout and Analysis Software for the Ultra-High Rate Germanium (UHRGe) Project

Description: High-resolution high-purity germanium (HPGe) spectrometers are needed for Safeguards applications such as spent fuel assay and uranium hexafluoride cylinder verification. In addition, these spectrometers would be applicable to other high-rate applications such as non-destructive assay of nuclear materials using nuclear resonance fluorescence. Count-rate limitations of today's HPGe technologies, however, lead to concessions in their use and reduction in their efficacy. Large-volume, very high-ra… more
Date: September 1, 2011
Creator: Fast, James E.; Aguayo Navarrete, Estanislao; Evans, Allan T.; VanDevender, Brent A.; Rodriguez, Douglas C. & Wood, Lynn S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Analytical techniques for ambient sulfate aerosols

Description: Work done to further develop the infrared spectroscopic analytical method for the analysis of atmospheric aerosol particles, as well as some exploratory work on a new procedure for determining proton acidity in aerosol samples is described. Earlier work had led to the successful use of infrared (ir) spectrophotometry for the analysis of nitrate, ammonium, and neutral and acidic sulfates in aerosol samples collected by an impactor on a Mylar-film substrate. In this work, a filter-extraction meth… more
Date: June 1, 1981
Creator: Johnson, S. A.; Graczyk, D. G.; Kumar, R. & Cunningham, P. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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ANNEALING OF GAMMA RAY INDUCED CHANGES IN ANTIMONY DOPED GERMANIUM

Description: An investigatiori of the annealing of the radioinduced carrier concentration change in Sb-doped Ge in the range 370 to 455 l K was made. The irradiations were conducted at liquid nitrogen temperature using Co/ sup 60/ gamma irradiation. A model that explains the observed behavior is presented. On the basis of the model, the observed annealing consists of vacancy diffusion simultaneously to impurity sites and annihilation centers. Analysis of the activation energy for the annealing process yield… more
Date: May 28, 1963
Creator: Pigg, J.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Annotated bibliography for liquid metal surface tensions of groups III-A, IV-A, and V-A metals. [82 references]

Description: An annotated bibliography has been prepared which includes summaries of 82 publications dating from 1920 and dealing with the measurement of the surface tensions of Groups III-A, IV-A, and V-A metals in the liquid state. The bibliography is organized by key element investigated, and contains a tabulation of correlations for surface tension as a function of temperature. A brief discussion dealing with variables and methods has been included.
Date: April 1, 1976
Creator: Murtha, M. J. & Burnet, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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