The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform

Michael Elliott Schoff - One of the best experts on this subject based on the ideXlab platform.

  • Sputter target erosion and its effects on long duration DC magnetron Sputter coating
    2011
    Co-Authors: Michael Elliott Schoff
    Abstract:

    Plasma discharge Sputter coaters have been used to create uniform thin layers of practically any target material. For Inertial Confinement Fusion research, a batch of several 1-2 mm diameter inertial fusion target shells are grown using several Sputter coaters that run for 2-3 weeks and use 2-3 targets per Gun. As the targets are consumed, a well documented ring or race track indentation develops on the target surface. The changing geometry of the target has been shown to affect the operating parameters of the Sputter Gun, as well as the quality of the deposition. Current methods do not achieve the quality and reproducibility that specifications demand. The purpose of this thesis is to characterize the Sputtering process as it evolves through the life of a target, to better understand the Sputtering process and ultimately to provide the means to produce higher quality, reproducible shells. Several production Sputter coaters were automated to provide enhanced control and process data as a function of time. An experiment was then conducted that documented the deposition from an unused copper target through 90% of its initial thickness in three separate runs. It was found that the Sputter yield matches with the empirical calculation, and is determined by the cathode voltage. The distribution of coated material for small theta; retains the cosine to the fourth power dependence, even as the Sputter yield decreases with increasing target erosion. As the target erodes, the Sputtered material is focused around small theta; because of changing target geometry and reSputtering.

  • Sputter target erosion and its effects on long duration DC magnetron Sputter coating - eScholarship
    2009
    Co-Authors: Michael Elliott Schoff
    Abstract:

    Plasma discharge Sputter coaters have been used to create uniform thin layers of practically any target material. For Inertial Confinement Fusion research, a batch of several 1-2 mm diameter inertial fusion target shells are grown using several Sputter coaters that run for 2-3 weeks and use 2-3 targets per Gun. As the targets are consumed, a well documented ring or race track indentation develops on the target surface. The changing geometry of the target has been shown to affect the operating parameters of the Sputter Gun, as well as the quality of the deposition. Current methods do not achieve the quality and reproducibility that specifications demand. The purpose of this thesis is to characterize the Sputtering process as it evolves through the life of a target, to better understand the Sputtering process and ultimately to provide the means to produce higher quality, reproducible shells. Several production Sputter coaters were automated to provide enhanced control and process data as a function of time. An experiment was then conducted that documented the deposition from an unused copper target through 90% of its initial thickness in three separate runs. It was found that the Sputter yield matches with the empirical calculation, and is determined by the cathode voltage. The distribution of coated material for small theta; retains the cosine to the fourth power dependence, even as the Sputter yield decreases with increasing target erosion. As the target erodes, the Sputtered material is focused around small theta; because of changing target geometry and reSputtering.

Ehrlich S. N. - One of the best experts on this subject based on the ideXlab platform.

  • Ultrahigh Vacuum Chamber for Synchrotron X-ray Diffraction from Films Adsorbed on Single-crystal Surfaces
    Hosted by Utah State University Libraries, 1992
    Co-Authors: Wang S. K., Dai P., Angot T., Taub H., Ehrlich S. N.
    Abstract:

    An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface

  • Ultrahigh vacuum chamber for synchrotron x‐ray diffraction from films adsorbed on single‐crystal surfaces
    'AIP Publishing', 1992
    Co-Authors: Dennison J. R., Wang S. K., Angot T., Dai, Pengcheng 1963-, Taub Haskell, Ehrlich S. N.
    Abstract:

    doi:10.1063/1.1143279An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface.This research was supported by U. S. NSF Grant Nos. DMR-8304366, DMR-8704938, and DMR-9011069 (H. T.), U. S. Department of Energy Grant No. DE-FG02-85ER45183 of the MATRIX Participating Research Team (S. N. E. and H.T.), University of Missouri Multicampus Weldon Springs Awards (H. T.), and a Research Council Grant of the University of Missouri-Columbia (H. T.)

Wang S. K. - One of the best experts on this subject based on the ideXlab platform.

  • Ultrahigh Vacuum Chamber for Synchrotron X-ray Diffraction from Films Adsorbed on Single-crystal Surfaces
    Hosted by Utah State University Libraries, 1992
    Co-Authors: Wang S. K., Dai P., Angot T., Taub H., Ehrlich S. N.
    Abstract:

    An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface

  • Ultrahigh vacuum chamber for synchrotron x‐ray diffraction from films adsorbed on single‐crystal surfaces
    'AIP Publishing', 1992
    Co-Authors: Dennison J. R., Wang S. K., Angot T., Dai, Pengcheng 1963-, Taub Haskell, Ehrlich S. N.
    Abstract:

    doi:10.1063/1.1143279An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface.This research was supported by U. S. NSF Grant Nos. DMR-8304366, DMR-8704938, and DMR-9011069 (H. T.), U. S. Department of Energy Grant No. DE-FG02-85ER45183 of the MATRIX Participating Research Team (S. N. E. and H.T.), University of Missouri Multicampus Weldon Springs Awards (H. T.), and a Research Council Grant of the University of Missouri-Columbia (H. T.)

Angot T. - One of the best experts on this subject based on the ideXlab platform.

  • Ultrahigh Vacuum Chamber for Synchrotron X-ray Diffraction from Films Adsorbed on Single-crystal Surfaces
    Hosted by Utah State University Libraries, 1992
    Co-Authors: Wang S. K., Dai P., Angot T., Taub H., Ehrlich S. N.
    Abstract:

    An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface

  • Ultrahigh vacuum chamber for synchrotron x‐ray diffraction from films adsorbed on single‐crystal surfaces
    'AIP Publishing', 1992
    Co-Authors: Dennison J. R., Wang S. K., Angot T., Dai, Pengcheng 1963-, Taub Haskell, Ehrlich S. N.
    Abstract:

    doi:10.1063/1.1143279An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single‐crystal surfaces using synchrotron x‐ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four‐axis diffractometer and can also be used independently of the x‐ray diffractometer. A low‐current, pulse‐counting, low‐energy electron diffraction/Auger spectroscopy system with a position‐sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x‐ray scattering position. A closed‐cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion Sputter Gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface.This research was supported by U. S. NSF Grant Nos. DMR-8304366, DMR-8704938, and DMR-9011069 (H. T.), U. S. Department of Energy Grant No. DE-FG02-85ER45183 of the MATRIX Participating Research Team (S. N. E. and H.T.), University of Missouri Multicampus Weldon Springs Awards (H. T.), and a Research Council Grant of the University of Missouri-Columbia (H. T.)

M Allen - One of the best experts on this subject based on the ideXlab platform.

  • direct experimental evidence of back surface ion acceleration from laser irradiated gold foils
    Physical Review Letters, 2004
    Co-Authors: M Allen, P K Patel, A Mackinnon, D Price, S C Wilks, Edward C Morse
    Abstract:

    Au foils were irradiated with a 100-TW, 100-fs laser at intensities greater than ${10}^{20}\text{ }\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2}$ producing proton beams with a total yield of $\ensuremath{\sim}{10}^{11}$ and maximum proton energy of $g9\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$. Removing contamination from the back surface of Au foils with an Ar-ion Sputter Gun reduced the total yield of accelerated protons to less than 1% of the yield observed without removing contamination. Removing contamination from the front surface (laser-interaction side) of the target had no observable effect on the proton beam. We present a one-dimensional particle-in-cell simulation that models the experiment. Both experimental and simulation results are consistent with the back-surface acceleration mechanism described in the text.