Sample records for zr hf rf

  1. Determination of the density of the defect states in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} high-k film Deposited by using rf-magnetron sputtering technique

    SciTech Connect (OSTI)

    Lu, W.; Lu, J. X.; Ou, X.; Liu, X. J.; Cao, Y. Q.; Li, A. D.; Xu, B.; Xia, Y. D.; Yin, J.; Liu, Z. G. [National Laboratory of Solid State Microstructures, and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2014-08-15T23:59:59.000Z

    A memory structure Pt/Al{sub 2}O{sub 3}/Hf{sub 0.5}Zr{sub 0.5}O{sub 2}/Al{sub 2}O{sub 3}/p-Si was fabricated by using atomic layer deposition and rf-magnetron sputtering techniques, and its microstructure has been investigated by using the high resolution transmission electron microscopy (HRTEM). By measuring the applied gate voltage dependence of the capacitance for the memory structure, the planar density of the trapped charges in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} high-k film was estimated as 6.63 × 10{sup 12} cm{sup ?2}, indicating a body defect density of larger than 2.21 × 10{sup 19} cm{sup ?3}. It is observed that the post-annealing in N{sub 2} can reduces the defect density in Hf{sub 0.5}Zr{sub 0.5}O{sub 2} film, which was ascribed to the occupancy of oxygen vacancies by nitrogen atoms.

  2. Analyses of femtosecond laser ablation of Ti, Zr, Hf

    E-Print Network [OSTI]

    Grojo, D; Bruneau, S; Itina, T

    2003-01-01T23:59:59.000Z

    Femtosecond laser ablation of Ti, Zr and Hf has been investigated by means of in-situ plasma diagnostics. Fast plasma imaging with the aid of an intensified charged coupled device (ICCD) camera was used to characterise the plasma plume expansion on a nanosecond time scale. Time- and spaceresolved optical emission spectroscopy was employed to perform time-of-flight measurements of ions and neutral atoms. It is shown that two plasma components with different expansion velocities are generated by the ultra-short laser ablation process. The expansion behaviour of these two components has been analysed as a function of laser fluence and target material. The results are discussed in terms of mechanisms responsible for ultra-short laser ablation.

  3. Ternary ceramic alloys of Zr-Ce-Hf oxides

    DOE Patents [OSTI]

    Becher, P.F.; Funkenbusch, E.F.

    1990-11-20T23:59:59.000Z

    A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

  4. First-principles phase diagram calculations for the HfCTiC, ZrCTiC, and HfCZrC solid O. Adjaoud,1,*,

    E-Print Network [OSTI]

    Steinle-Neumann, Gerd

    with and without approximations for excess vibrational free energies. Significant miscibility gaps are predicted vibrational free energy are estimated to be 7%, 20%, and 0%, for HfC­TiC, TiC­ZrC, and HfC­ZrC, respectively semiempirical methods exist to construct phase diagrams based on approximate free-energy functions

  5. Ternary ceramic alloys of ZR-CE-HF oxides

    DOE Patents [OSTI]

    Becher, Paul F. (Oak Ridge, TN); Funkenbusch, Eric F. (White Bear Lake, MN)

    1990-01-01T23:59:59.000Z

    A ternary ceramic alloy which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce.sub.x Hf.sub.y Zn.sub.1-x-y O.sub.2, is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites.

  6. A new class of materials with promising thermoelectric properties: MNiSn (M=Ti, Zr, Hf)

    SciTech Connect (OSTI)

    Hohl, H.; Ramirez, A.P.; Kaefer, W.; Fess, K.; Thurner, Ch.; Kloc, Ch.; Bucher, E.

    1997-07-01T23:59:59.000Z

    TiNiSn, ZrNiSn and HfNiSn are members of a large group of intermetallic compounds which crystallize in the cubic MgAgAs-type structure. Polycrystalline samples of these compounds have been prepared and investigated for their thermoelectric properties. With thermopowers of about {minus}200 {micro}V/K and resistivities of a few m{Omega}cm, power factors S{sup 2}/{rho} as high as 38 {micro}W/K{sup 2}cm were obtained at 700 K. These remarkably high power factors are, however, accompanied by a thermal conductivity, solid solutions Zr{sub 1{minus}x}Hf{sub x}NiSn, Zr{sub 1{minus}x}Ti{sub x}NiSn, and Hf{prime}{sub 1{minus}x}Ti{sub x}NiSn were formed. The figure of merit of Zr{sub 0.5}Hf{sub 0.5}NiSn at 700 K (ZT = 0.41) exceeds the end members ZrNiSn (ZT = 0.26) and HfNiSn (ZT = 0.22).

  7. Effects of ZrO{sub 2} doping on HfO{sub 2} resistive switching memory characteristics

    SciTech Connect (OSTI)

    Ryu, Seung Wook; Kwac, Jungsuk; Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Cho, Seongjae, E-mail: felixcho@gachon.ac.kr [Department of Electronic Engineering and New Technology Component and Material Research Center (NCMRC), Gachon University, Seongnam-si, Gyeonggi-do 461-741 (Korea, Republic of); Park, Joonsuk [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Hyeong Joon [Department of Materials Science and Engineering and Inter-university Semiconductor Research Center (ISRC), Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-08-18T23:59:59.000Z

    A resistive switching (RS) random access memory device with ZrO{sub 2}-doped HfO{sub 2} exhibits better RS performance than that with pure HfO{sub 2}. In particular, I{sub res}, V{sub res}, and V{sub set} are reduced by approximately 58%, 38%, and 39%, respectively, when HfO{sub 2} is doped with ZrO{sub 2} (9 at.?%). In addition, the ZrO{sub 2} doping in HfO{sub 2} makes the distribution of most parameters steeper. Transmission electron microscopy (TEM) analysis reveals that the deposited zirconium-doped hafnium oxide (HZO) (9 at.?%) is polycrystalline. Elemental mapping results by scanning TEM–energy dispersive spectroscopy also prove that ZrO{sub 2} is uniformly distributed in the HZO (9 at.?%) film. The possible mechanism for the improvement in the RS characteristics is also suggested on the basis of the X-ray photoelectron spectroscopy results and filamentary RS mechanism. These results suggest that the ZrO{sub 2} doping into HfO{sub 2} likely not only will reduce power consumption but also will improve cyclic endurance by controlling the nonstoichiometric phase.

  8. Continuous production of granular or powder Ti, Zr and Hf or their alloy products

    DOE Patents [OSTI]

    White, Jack C. (Albany, OR); Oden, Laurance L. (Albany, OR)

    1993-01-01T23:59:59.000Z

    A continuous process for producing a granular metal selected from the group consisting of Ti, Zr or Hf under conditions that provide orderly growth of the metal free of halide inclusions comprising: a) dissolving a reducing metal selected from the group consisting of Na, Mg, Li or K in their respective halide salts to produce a reducing molten salt stream; b) preparing a second molten salt stream containing the halide salt of Ti, Zr or Hf; c) mixing and reacting the two molten streams of steps a) and b) in a continuous stirred tank reactor; d) wherein steps a) through c) are conducted at a temperature range of from about 800.degree. C. to about 1100.degree. C. so that a weight percent of equilibrium solubility of the reducing metal in its respective halide salt varies from about 1.6 weight percent at about 900.degree. C. to about 14.4 weight percent at about 1062.degree. C.; and wherein a range of concentration of the halide salt of Ti, Zn or Hf in molten halides of Na, Mg, Li or K is from about 1 to about 5 times the concentration of Na, Mg, Li or K; e) placing the reacted molten stream from step c) in a solid-liquid separator to recover an impure granular metal product by decantation, centrifugation, or filtration; and f) removing residual halide salt impurity by vacuum evaporator or inert gas sweep at temperatures from about 850.degree. C. to 1000.degree. C. or cooling the impure granular metal product to ambient temperature and water leaching off the residual metal halide salt.

  9. Electric transport properties of the pentatelluride materials HfTe{sub 5} and ZrTe{sub 5}

    SciTech Connect (OSTI)

    Tritt, T.M.; Wilson, M.L.; Littleton, R.L. [and others

    1997-07-01T23:59:59.000Z

    The authors have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe{sub 5} and ZrTe{sub 5}. They have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, T{sub p} where T{sub p} {approx} 80K for HfTe{sub 5} and T{sub p} {approx} 145K for ZrTe{sub 5}. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. These data are similar to behavior observed previously in these materials. They have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe{sub 5} and ZrTe{sub 5}. They have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 {micro}V/K and +65 {micro}V/K for HfTe{sub 5} and ZrTe{sub 5}, respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 {micro}V/K for HfTe{sub 5} and +35 {micro}V/K for ZrTe{sub 5}. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T {approx} 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 m{Omega}-cm and 24 m{Omega}-cm for HfTe{sub 5} and ZrTe{sub 5} respectively, compared to single crystal values of 0.35 m{Omega}-cm (HfTe{sub 5}) and 1.0 m{Omega}-cm (ZrTe{sub 5}). The authors have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. They will discuss these materials in relation to their potential as candidates for thermoelectric applications.

  10. Microstructural Characterization and Shape Memory Response of Ni-Rich NiTiHf and NiTiZr High Temperature Shape Memory Alloys

    E-Print Network [OSTI]

    Evirgen, Alper

    2014-08-14T23:59:59.000Z

    NiTiHf and NiTiZr high temperature shape memory alloys (HTSMAs) have drawn a great deal of attention as cheaper alternatives to Pt, Pd and Au alloyed NiTi-based HTSMAs while NiTiZr alloys also providing at least 20% weight reduction then its Ni...

  11. Electron-stimulated desorption from polished and vacuum fired 316LN stainless steel coated with Ti-Zr-Hf-V

    SciTech Connect (OSTI)

    Malyshev, Oleg B., E-mail: oleg.malyshev@stfc.ac.uk; Valizadeh, Reza; Hogan, Benjamin T.; Hannah, Adrian N. [ASTeC, STFC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD Cheshire (United Kingdom)

    2014-11-01T23:59:59.000Z

    In this study, two identical 316LN stainless steel tubular samples, which had previously been polished and vacuum-fired and then used for the electron-stimulated desorption (ESD) experiments, were coated with Ti-Zr-Hf-V with different morphologies: columnar and dense. ESD measurement results after nonevaporable getter (NEG) activation to 150, 180, 250, and 350?°C indicated that the values for the ESD yields are significantly (2–20 times) lower than the data from our previous study with similar coatings on nonvacuum-fired samples. Based on these results, the lowest pressure and best long-term performance in particle accelerators will be achieved with a vacuum-fired vacuum chamber coated with dense Ti-Zr-Hf-V coating activated at 180?°C. This is likely due to the following facts: after NEG activation, the hydrogen concentration inside the NEG was lower than in the bulk stainless steel substrate; the NEG coating created a barrier for gas diffusion from the sample bulk to vacuum; the dense NEG coating performed better as a barrier than the columnar NEG coating.

  12. First principle study of elastic and thermodynamic properties of ZrZn{sub 2} and HfZn{sub 2} under high pressure

    SciTech Connect (OSTI)

    Sun, Na; Zhang, Xinyu, E-mail: jiaqianqin@gmail.com; Ning, Jinliang; Zhang, Suhong; Liang, Shunxing; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Qin, Jiaqian, E-mail: jiaqianqin@gmail.com [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand)

    2014-02-28T23:59:59.000Z

    A comprehensive investigation of the structural, elastic, and thermodynamic properties for Laves-phases ZrZn{sub 2} and HfZn{sub 2} are conducted using density functional total energy calculations combined with the quasi-harmonic Debye model. The optimized lattice parameters of ZrZn{sub 2} and HfZn{sub 2} compare well with available experimental values. We estimated the mechanical behaviors of both compounds under compression, including mechanical stability, Young's modulus, Poisson's ratio, ductility, and anisotropy. Additionally, the thermodynamic properties as a function of pressure and temperature are analyzed and found to be in good agreement with the corresponding experimental data.

  13. 13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of Western Ontario, London, ON, Canada

    E-Print Network [OSTI]

    Chakhmouradian, Anton

    13.21 Geochemistry of the Rare-Earth Element, Nb, Ta, Hf, and Zr Deposits RL Linnen, University of rare metals in natural fluids 551 13.21.2.2.2 Aqueous complexation and mineral solubility 552 13 Acknowledgments 564 References 564 13.21.1 Introduction Rare-element mineral deposits, also called rare-metal

  14. Density functional theory study of first-layer adsorption of ZrO2 and HfO2 on Ge(100)

    E-Print Network [OSTI]

    Kummel, Andrew C.

    Density functional theory study of first-layer adsorption of ZrO2 and HfO2 on Ge(100) T.J. Grassman on the Ge(100)-4 Â 2 surface. Surface binding geometries of metal-down (O­M­Ge) and oxygen-down (M­ O­Ge) were considered, including both adsorbate and displacement geometries of M­O­Ge. Calculated enthalpies

  15. Mechanical properties of ZrB2- and HfB2-based ultra-high temperature ceramics fabricated by spark plasma sintering

    SciTech Connect (OSTI)

    Zapata-Solvas, E. [Imperial College, London; Jayaseelan, D. [Imperial College, London; Lin, Hua-Tay [ORNL; Brown, P. [DSTL, Porton Down, Salisbury, Wiltshire, UK; Lee, W.E. [Imperial College, London

    2013-01-01T23:59:59.000Z

    Flexural strengths at room temperature, at 1400 C in air and at room temperature after 1 h oxidation at 1400 C were determined for ZrB2- and HfB2-based ultra-high temperature ceramics (UHTCs). Defects caused by electrical discharge machining (EDM) lowered measured strengths significantly and were used to calculate fracture toughness via a fracture mechanics approach. ZrB2 with 20 vol.% SiC had room temperature strength of 700 90 MPa, fracture toughness of 6.4 0.6 MPa, Vickers hardness at 9.8 N load of 21.1 0.6 GPa, 1400 C strength of 400 30 MPa and room temperature strength after 1 h oxidation at 1400 C of 678 15 MPa with an oxide layer thickness of 45 5 m. HfB2 with 20 vol.% SiC showed room temperature strength of 620 50 MPa, fracture toughness of 5.0 0.4 MPa, Vickers hardness at 9.8 N load of 27.0 0.6 GPa, 1400 C strength of 590 150 MPa and room temperature strength after 1 h oxidation at 1400 C of 660 25 MPa with an oxide layer thickness of 12 1 m. 2 wt.% La2O3 addition to UHTCs slightly reduced mechanical performance while increasing tolerance to property degradation after oxidation and effectively aided internal stress relaxation during spark plasma sintering (SPS) cooling, as quantified by X-ray diffraction (XRD). Slow crack growth was suggested as the failure mechanism at high temperatures as a consequence of sharp cracks formation during oxidation.

  16. Exploration of R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd2AlGe2 and Analysis of the U3Si2 and Zr3Al2 Structure Types

    SciTech Connect (OSTI)

    Sean William McWhorter

    2006-05-01T23:59:59.000Z

    In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} several new compounds were synthesized with different crystal structures, but similar structural features. In Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} can be thought of as being formed from two 3{sup 2}434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd{sub 2}MgGe{sub 2} and Gd{sub 2}InGe{sub 2} both possess the same 3{sup 2}434 nets of Gd atoms as Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, but these nets are connected differently, forming the Mo{sub 2}FeB{sub 2} crystal structure. A search of the literature revealed that compounds with the composition R{sub 2}XM{sub 2} (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo{sub 2}FeB{sub 2}, Zr{sub 3}Al{sub 2}, Mn{sub 2}AlB{sub 2} and W{sub 2}CoB{sub 2} crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd{sub 2}AlGe{sub 2} forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how electrons can be accounted for. A series of electronic structure calculations were performed on models with the U{sub 3}Si{sub 2} and Zr{sub 3}Al{sub 2} structures, using Zr and A1 as the building blocks. The starting point for these models was the U{sub 3}Si{sub 2} structure, and models were created to simulate the transition from the idealized U{sub 3}Si{sub 2} structure to the distorted Zr{sub 3}Al{sub 2} structure. Analysis of the band structures of the models has shown that the transition from the U{sub 3}Si{sub 2} structure to the Zr{sub 3}Al{sub 2} structure lifts degeneracies along the {Lambda} {yields} Z direction, indicating a Peierls-type mechanism for the displacement occurring in the positions of the Zr atoms.

  17. Thermoelectric performance of nanostructured p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 1?x}Sn{sub x} half-Heusler alloys

    SciTech Connect (OSTI)

    Maji, Pramathesh; Makongo, Julien P.A. [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Zhou, Xiaoyuan; Chi, Hang; Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2013-06-15T23:59:59.000Z

    Several compositions of the p-type half-Heusler alloys Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 1?x}Sn{sub x} (0?x?0.4) were synthesized by mechanically alloying high purity elemental powders using hardened steel jars and balls on a high energy shaker mill. Powder X-ray diffraction (XRD) investigations of several aliquots taken after regularly spaced milling time suggested that single phase products with half-Heusler (HH) structure can be obtained after 10 h. However, XRD and transmission electron microscopy (TEM) studies of several specimens obtained from compacted polycrystalline powders of Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 1?x}Sn{sub x} alloys using a uniaxial hot press (HP) revealed the presence of CoSb inclusions with various sizes embedded inside the HH matrix. Hall effect, electrical conductivity, and thermopower data collected between 300 K and 775 K on several compositions suggested that electronic transport in the synthesized Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 1?x}Sn{sub x}/CoSb composites strongly depends on the average size and/or mole fraction of the embedded CoSb inclusions rather than the fraction (x) of Sn substituting for Sb. Among the samples investigated, the nanocomposite with x=0.2, which contains nanometer-scale CoSb inclusions, showed the largest power factor (800 ?W/K{sup 2} m at 775 K) and the lowest lattice thermal conductivity (?2.2 W/m K at 775 K) leading to a six-fold enhancement in the figure of merit when compared to the Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 0.99}Sn{sub 0.01} bulk matrix. - Graphical abstract: CoSb nanoinclusions embedded into a p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 0.4}Rh{sub 0.6}Sb{sub 1?x}Sn{sub x} half-Heusler matrix simultaneously boost the thermopower and carrier mobility leading to a drastic enhancement of the power factor of the resulting bulk nanostructured materials. - Highlights: • The phase composition of half-Heusler (HH) alloy is very sensitive to the synthesis method. • Mechanical alloying (MA) of elements results in bulk HH matrix with CoSb inclusions. • CoSb nanoinclusions simultaneously boost the thermopower and carrier mobility with the HH matrix. • The MA process reduces lattice thermal conductivity due to high density of grain boundaries.

  18. Hf Transition Probabilities and Abundances

    E-Print Network [OSTI]

    J. E. Lawler; E. A. Den Hartog; Z. E. Labby; C. Sneden; J. J. Cowan; I. I. Ivans

    2006-11-01T23:59:59.000Z

    Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf/La) = -0.13 +/- 0.02 (sigma = 0.06) and log epsilon (Hf/Eu) = +0.04 +/- 0.02 (sigma = 0.06). The observed average stellar abundance ratio of Hf/Eu and La/Eu is larger than previous estimates of the solar system r-process-only value, suggesting a somewhat larger contribution from the r-process to the production of Hf and La. The newly determined Hf values could be employed as part of the chronometer pair, Th/Hf, to determine radioactive stellar ages.

  19. Superconducting RF Cryomodule Demagnetization

    E-Print Network [OSTI]

    Crawford, Anthony C

    2015-01-01T23:59:59.000Z

    This note presents measurements that support the proposition that it is feasible to demagnetize a fully assembled superconducting RF cryomodule.

  20. Rf Feedback free electron laser

    DOE Patents [OSTI]

    Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  1. Magnetic properties of HITPERM ,,Fe,Co...88Zr7B4Cu1 magnets M. A. Willard,a)

    E-Print Network [OSTI]

    Laughlin, David E.

    power applications requires new bulk soft magnetic materials that 1 are capable of operating at higher magnetization that persists to the phase transformation at 980 °C. Alternating current permeability experiments nanocrystalline Fe­Si­B­Nb­Cu alloys and nanocrystalline Fe­M­B­Cu M Zr, Nb, Hf, etc. alloys have been optimized

  2. Phase stable RF transport system

    DOE Patents [OSTI]

    Curtin, Michael T. (Los Alamos, NM); Natter, Eckard F. (San Francisco, CA); Denney, Peter M. (Los Alamos, NM)

    1992-01-01T23:59:59.000Z

    An RF transport system delivers a phase-stable RF signal to a load, such as an RF cavity of a charged particle accelerator. A circuit generates a calibration signal at an odd multiple frequency of the RF signal where the calibration signal is superimposed with the RF signal on a common cable that connects the RF signal with the load. Signal isolating diplexers are located at both the RF signal source end and load end of the common cable to enable the calibration to be inserted and extracted from the cable signals without any affect on the RF signal. Any phase shift in the calibration signal during traverse of the common cable is then functionally related to the phase shift in the RF signal. The calibration phase shift is used to control a phase shifter for the RF signal to maintain a stable RF signal at the load.

  3. Collisional quenching of highly rotationally excited HF

    E-Print Network [OSTI]

    Yang, Benhui; Forrey, R C; Stancil, P C; Balakrishnan, N

    2015-01-01T23:59:59.000Z

    Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H$_2$ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to $j=20$ were performed for kinetic energies from 10$^{-5}$ to 15000...

  4. RF test bench automation Description

    E-Print Network [OSTI]

    Dobigeon, Nicolas

    RF test bench automation Description: Callisto would like to implement automated RF test bench. Three RF test benches have to be studied and automated: LNA noise temperature test bench LNA gain phase of the test benches and an implementation of the automation phase. Tasks: Noise temperature

  5. Removal of uranium from aqueous HF solutions

    DOE Patents [OSTI]

    Pulley, Howard (West Paducah, KY); Seltzer, Steven F. (Paducah, KY)

    1980-01-01T23:59:59.000Z

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

  6. Ion source with external RF antenna

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Ji, Qing; Wilde, Stephen

    2005-12-13T23:59:59.000Z

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.

  7. Mobile HF Sources Research & Applica5ons

    E-Print Network [OSTI]

    Anlage, Steven

    of the new physics concepts · Collaborate with the Arecibo, HAARP, SURA and EISCAT, Transmi8er Power, ERP, sweeping rate, modula5on, pulse length #12;THE HAARP HEATER Acceleration (HAARP at 1 MW, EISCAT) 7 #12;Fron5er IM Issues - Examples HF-Induced Ar5ficial

  8. RF power generation

    E-Print Network [OSTI]

    Carter, R G

    2011-01-01T23:59:59.000Z

    This paper reviews the main types of r.f. power amplifiers which are, or may be, used for particle accelerators. It covers solid-state devices, tetrodes, inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for the different technologies.

  9. Kinetics Of Charge Generation During Formation Of Hf And Zr Silicate Dielectrics

    E-Print Network [OSTI]

    Gougousi, Theodosia

    shadow masks. Capacitance vs. voltage (CV) measurements are performed with a HP4284 impedance meter at 1 (600 or 900°C) on the flatband voltage using capacitance vs. voltage measurements. We find, the films are oxidized ex-situ in a tube furnace at 600°C in the presence of N2O, a process that is known

  10. Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    that two plasma components with different expansion velocities are generated by the ultra-short laser sources, the thermal damage of the material is strongly reduced when using ultra-short laser pulses fluence and target material. The results are discussed in terms of mechanisms responsible for ultra-short

  11. Metal-Organic Frameworks Based on Previously Unknown Zr8/Hf Cubic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > The EnergyCenter (LMI-EFRC)MaRIETechnologiesMesdi

  12. ELF/VLF PHASED ARRAY GENERATION VIA FREQUENCY-MATCHED STEERING OF A CONTINUOUS HF

    E-Print Network [OSTI]

    .6 MW HAARP HF heating facility in Alaska, we show that proper utilization of motion of the HF beam can

  13. The MUCOOL RF Program

    SciTech Connect (OSTI)

    Norem, J.; /Argonne; Bross, A.; Moretti, A.; Norris, B.; Qian, Z.; /Fermilab; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Li, D.; Virostek, S.; Zisman, M.; /LBL,; Sandstrom, R.; /Geneva U.

    2006-06-26T23:59:59.000Z

    Efficient muon cooling requires high RF gradients in the presence of high (3T) solenoidal fields. The Muon Ionization Cooling Experiment (MICE) also requires that the x-ray production from these cavities is low, in order to minimize backgrounds in the particle detectors that must be located near the cavities. These cavities require thin Be windows to ensure the highest fields on the beam axis. In order to develop these cavities, the MUCOOL RF Program was started about 6 years ago. Initial measurements were made on a six-cell cavity and a single-cell pillbox, both operating at 805 MHz. We have now begun measurements of a 201 MHz pillbox cavity. This program has led to new techniques to look at dark currents, a new model for breakdown and a general model of cavity performance based on surface damage. The experimental program includes studies of thin Be windows, conditioning, dark current production from different materials, magnetic-field effects and breakdown.

  14. Numerical prediction of the thermodynamic properties of ternary Al-Ni-Hf alloys

    SciTech Connect (OSTI)

    Romanowska, Jolanta; Kotowski, S?awomir; Zagula-Yavorska, Maryana [Rzeszów University of Technology (Poland)

    2014-10-06T23:59:59.000Z

    Thermodynamic properties of ternary Al-Hf-Ni system, such as {sup ex}G, ?{sub Al}, ?{sub Ni} and ?{sub Zr} at 1373K were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting {sup ex}G values was regarded as the calculation of excess Gibbs energy values inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of {sup ex}G on all legs of the triangle are known. {sup ex}G and L{sub ijk} ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism are calculated numerically using Wolfram Mathematica 9 software.

  15. Device Fabrication and Processing > Thin Film ALD, RF/DC Magnetic Materials and Co-

    E-Print Network [OSTI]

    Das, Suman

    .ien.gatech.edu Materials Processed > Dielectrics: SiO2, Si3N4,SiC, HfO2, ZnO, ZrO2, AlN, TiN, TiO2, Al2O3, additional dielectrics on request > Metals: Al, Cr, Ti, W, Ni, Mo, Pt, Fe, Cu, Ir, Pd, Ag, additional metals by request RIE; HBr-based ICP; Metals ­ Al, Cr, Ti, W, Ag > Wet Etching: SiO2, Si3N4 Metals, Organic materials

  16. Unbalanced field RF electron gun

    DOE Patents [OSTI]

    Hofler, Alicia

    2013-11-12T23:59:59.000Z

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  17. HF separation in a carbonylation process

    SciTech Connect (OSTI)

    Grote, D.; Trivedi, B.C.; Mason, T.O.

    1987-04-28T23:59:59.000Z

    This patent describes the carbonylation of an olefin with carbon monoxide in the presence of hydrogen fluoride catalyst wherein the reaction product is treated with water to produce a mixture of a carboxylic acid, HF and optionally water. The improvement comprises contacting at a temperature in the range of from about 25/sup 0/C up to about 100/sup 0/C, the mixture with one side of a cation permeable membrane of a copolymer of tetrafluoro ethylene and perfluoro-3, 6-dioxa-4-methyl-octen sulfamic acid whose other side is in contact with water.

  18. Phase modulation in RF tag

    DOE Patents [OSTI]

    Carrender, Curtis Lee; Gilbert, Ronald W.

    2007-02-20T23:59:59.000Z

    A radio frequency (RF) communication system employs phase-modulated backscatter signals for RF communication from an RF tag to an interrogator. The interrogator transmits a continuous wave interrogation signal to the RF tag, which based on an information code stored in a memory, phase-modulates the interrogation signal to produce a backscatter response signal that is transmitted back to the interrogator. A phase modulator structure in the RF tag may include a switch coupled between an antenna and a quarter-wavelength stub; and a driver coupled between the memory and a control terminal of the switch. The driver is structured to produce a modulating signal corresponding to the information code, the modulating signal alternately opening and closing the switch to respectively decrease and increase the transmission path taken by the interrogation signal and thereby modulate the phase of the response signal. Alternatively, the phase modulator may include a diode coupled between the antenna and driver. The modulating signal from the driver modulates the capacitance of the diode, which modulates the phase of the response signal reflected by the diode and antenna.

  19. Cryogenic vacuumm RF feedthrough device

    DOE Patents [OSTI]

    Wu, Genfa (Yorktown, VA); Phillips, Harry Lawrence (Hayes, VA)

    2008-12-30T23:59:59.000Z

    A cryogenic vacuum rf feedthrough device comprising: 1) a probe for insertion into a particle beam; 2) a coaxial cable comprising an inner conductor and an outer conductor, a dielectric/insulating layer surrounding the inner conductor, the latter being connected to the probe for the transmission of higher mode rf energy from the probe; and 3) a high thermal conductivity stub attached to the coaxial dielectric about and in thermal contact with the inner conductor which high thermal conductivity stub transmits heat generated in the vicinity of the probe efficiently and radially from the area of the probe and inner conductor all while maintaining useful rf transmission line characteristics between the inner and outer coaxial conductors.

  20. DEPARTMENT OF CHEMICAL ENGINEERING Name of SOP Manual Hydrofluoric Acid (HF) Etching of Glass

    E-Print Network [OSTI]

    Thompson, Michael

    required Fume Hood, safety eye goggles, lab coat, two layers of nitrile gloves and HF Safety Kit Sequential containers. 5. HF is a glass etchant; only use plastic labware to contain HF. 6. Personal protective gear

  1. Negative ion source with external RF antenna

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

    2007-02-13T23:59:59.000Z

    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  2. advanced rf gun: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    attached to the RF gun is shown in Fig. 1. The RF gun is an L-band 1 12- cell RF gun 4 TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities Physics...

  3. High-Power Rf Load

    DOE Patents [OSTI]

    Tantawi, Sami G. (San Mateo, CA); Vlieks, Arnold E. (Livermore, CA)

    1998-09-01T23:59:59.000Z

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  4. Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

    SciTech Connect (OSTI)

    Witusiewicz, V.T.; Sommer, F.

    2000-04-01T23:59:59.000Z

    Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni{sub 26}Zr{sub 74}. In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys.

  5. Amorphous powders of Al-Hf prepared by mechanical alloying

    SciTech Connect (OSTI)

    Schwarz, R.B.; Hannigan, J.W.; Sheinberg, H.; Tiainen, T.

    1988-01-01T23:59:59.000Z

    We synthesized amorphous Al/sub 50/Hf/sub 50/ alloy powder by mechanically alloying an equimolar mixture of crystalline powders of Al and Hf using hexane as a dispersant. We characterized the powder as a function of mechanical-alloying time by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry. Amorphous Al/sub 50/Hf/sub 50/ powder heated at 10 K s/sup /minus/1/ crystallizes polymorphously at 1003 K into orthorhombic AlHf (CrB-type structure). During mechanical alloying, some hexane decomposes and hydrogen and carbon are incorporated into the amorphous alloy powder. The hydrogen can be removed by annealing the powder by hot pressing at a temperature approximately 30 K below the crystallization temperature. The amorphous compacts have a diamond pyramidal hardness of 1025 DPH. 24 refs., 7 figs., 1 tab.

  6. Theoretical Assessment of 178m2Hf De-Excitation

    SciTech Connect (OSTI)

    Hartouni, E P; Chen, M; Descalle, M A; Escher, J E; Loshak, A; Navratil, P; Ormand, W E; Pruet, J; Thompson, I J; Wang, T F

    2008-10-06T23:59:59.000Z

    This document contains a comprehensive literature review in support of the theoretical assessment of the {sup 178m2}Hf de-excitation, as well as a rigorous description of controlled energy release from an isomeric nuclear state.

  7. Low jitter RF distribution system

    DOE Patents [OSTI]

    Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

    2012-09-18T23:59:59.000Z

    A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

  8. Single electron beam rf feedback free electron laser

    DOE Patents [OSTI]

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11T23:59:59.000Z

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  9. RF-SPUTTERED ITO AND ITO:Zr STUDIED BY IN SITU SPECTROSCOPIC ELLIPSOMETRY

    E-Print Network [OSTI]

    Weiss, Sharon

    . Weiss 4 , Bridget R. Rogers 5 1 National Renewable Energy Laboratory, National Center for Photovoltaics typically exhibit an increase in either optical or electrical properties (one at the expense of the other

  10. Submitted to J. Vac. Sci. Technol., December 11, 1998 1 Growth of Hf and HfN on GaN by Molecular Beam Epitaxy

    E-Print Network [OSTI]

    Cohen, Philip I.

    Submitted to J. Vac. Sci. Technol., December 11, 1998 1 Growth of Hf and HfN on GaN by Molecular-type GaN(000¯1) by MBE using a custom built Hf electron beam source and an ammonia leak. The films were). It was found that epitaxial growth of Hf is possible even at room temperature. GaN films varying in thickness

  11. RF Systems in a Neutrino Factory

    SciTech Connect (OSTI)

    Berg J. S.

    2012-09-07T23:59:59.000Z

    Based on existing sources, I compile parameters for the RF systems for a neutrino factory which accelerates to 10 GeV.

  12. RF/optical shared aperture for high availability wideband communication RF/FSO links

    DOE Patents [OSTI]

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2014-04-29T23:59:59.000Z

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  13. Predictions of microwavePredictions of microwave breakdown in rf structuresbreakdown in rf structures

    E-Print Network [OSTI]

    Yu, Ming

    Predictions of microwave breakdownPredictions of microwave breakdown in rf structuresin rf structures #12;2 of the breakdown phenomenon). 2. Electron interaction with microwave field (rough estimates of parameters which in communication systems Predictions of microwave breakdown in rf structuresPredictions of microwave breakdown

  14. RF power recovery feedback circulator

    DOE Patents [OSTI]

    Sharamentov, Sergey I. (Bolingbrook, IL)

    2011-03-29T23:59:59.000Z

    A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

  15. Acidizing of Sandstone Reservoirs Using HF and Organic Acids

    E-Print Network [OSTI]

    Yang, Fei

    2012-10-19T23:59:59.000Z

    funnel and 0.2 µm filter paper. The concentrations of Si, Al, Ca, Mg, Fe in filtrate were analyzed by inductively coupled plasma (ICP) analysis using Optima 7000 DV ICP- OES system and WinLab 32TM software. The solid part was dried under room..., Mg, Fe, Al, and Si by ICP analysis using Optima 7000 DV ICP- OES system and WinLab 32TM software. 2.2.4 Core flood experiments on Berea sandstone cores using different amounts of HF To investigate the effect of HF amount on the outcome...

  16. Hole Trapping at Surfaces of mZrO2 and mHfO2 Nanocrystals. |...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    surface. These fundamental results are relevant to mechanisms of water oxidation, photocatalysis, contact charging, and photodesorption. Citation: Wolf MJ, KP Mckenna, and AL...

  17. Robust Diamond-Based RF Switch Yields Enhanced Communication...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Robust Diamond-Based RF Switch Yields Enhanced Communication Capabilities Technology available for licesning: A radio frequency (RF) microelectromechanical system (MEMS) switch...

  18. Linear Gain for the Microbunching Instability in an RF Compressor

    E-Print Network [OSTI]

    Venturini, M.

    2010-01-01T23:59:59.000Z

    Instability in an RF Compressor M. Venturini Lawrencefor investigating this instability in rf compressors. We useapplied to magnetic compressors [2, 3] and derive some

  19. Microwave (MW) and Radio Frequency (RF) as Enabling Technologies...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for Advanced Manufacturing Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for Advanced...

  20. High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    transmitter radiates a strong beam of high- frequency (HF) waves modulated at ELF. This HF heating modulates-frequency (HF) radiation in the megahertz range [7]. This heating modulates the electron's temperature in the D

  1. Early (4.5 Ga) formation of terrestrial crust: LuHf, 18 thermometry results for Hadean zircons

    E-Print Network [OSTI]

    Harrison, Mark

    of the volumetrically larger domain sampled by laser drilling against the spatially more restricted ion microprobe ages the characterization of 176 Hf/177 Hf initial ratios (Hf ) in Hadean zircons by acquiring a further 116 laser ablation

  2. Thermoelectric Transport in a ZrN/ScN Superlattice

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    at Springerlink.com Thermoelectric Transport in a ZrN/ScNthe potential for a high thermoelectric ?gure of merit. Theexperimental studies of the thermoelectric transport in ZrN/

  3. Superior Performance of HIS-SelectTM HF Nickel

    E-Print Network [OSTI]

    Lebendiker, Mario

    Superior Performance of HIS-SelectTM HF Nickel Affinity Gel By John Dapron, Michael Harvey, Heidi by immobilized metal affinity chromatography (IMAC), using nickel as the affinity ligand. Sigma-Aldrich has been expanding its line of specialty HIS-Select nickel chelate affinity media to meet the varied needs

  4. Some new methods of RF control

    SciTech Connect (OSTI)

    Jachim, S.P.

    1990-01-01T23:59:59.000Z

    This presentation will focus on several recent developments at Los Alamos in the area of RF control for accelerators. Included in the discussion will be in-phase/quadrature (I/Q) field control, the application of six-port reflectometers for cavity instrumentation and resonance control, a technique for phase stabilization of critical RF cables, an application of state-variable feedback for field control, and the direct integration of RF and computer-interface hardware using the VXIbus standard. 25 refs., 8 figs.

  5. Matching network for RF plasma source

    DOE Patents [OSTI]

    Pickard, Daniel S. (Palo Alto, CA); Leung, Ka-Ngo (Hercules, CA)

    2007-11-20T23:59:59.000Z

    A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.

  6. Multi-level RF identification system

    DOE Patents [OSTI]

    Steele, Kerry D.; Anderson, Gordon A.; Gilbert, Ronald W.

    2004-07-20T23:59:59.000Z

    A radio frequency identification system having a radio frequency transceiver for generating a continuous wave RF interrogation signal that impinges upon an RF identification tag. An oscillation circuit in the RF identification tag modulates the interrogation signal with a subcarrier of a predetermined frequency and modulates the frequency-modulated signal back to the transmitting interrogator. The interrogator recovers and analyzes the subcarrier signal and determines its frequency. The interrogator generates an output indicative of the frequency of the subcarrier frequency, thereby identifying the responding RFID tag as one of a "class" of RFID tags configured to respond with a subcarrier signal of a predetermined frequency.

  7. HF beam parameters in ELF/VLF wave generation via modulated heating of the ionosphere

    E-Print Network [OSTI]

    Program (HAARP) facility near Gakona, AK, we investigate the effect of HF frequency and beam size-ionosphere waveguide generally decreases with increasing HF frequency between 2.75­9.50 MHz. HAARP is also capable is then applied to also predict the effect of HF beam parameters on magnetospheric injection with HAARP. Citation

  8. Capacitive Behavior of HF Power Transformers: Global Approach to Draw Robust Equivalent Circuits

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    behavior of all components. Among these components, HF power transformers constitute a special case. EvenCapacitive Behavior of HF Power Transformers: Global Approach to Draw Robust Equivalent Circuits of n-windings HF power transformers. A global approach, mainly based on energy considerations about

  9. Degreasing and cleaning superconducting RF Niobium cavities

    SciTech Connect (OSTI)

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01T23:59:59.000Z

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  10. Superconducting RF Injector T. Srinivasan-Rao

    E-Print Network [OSTI]

    current injector Heat LossRF Requirements Superconducting injector Photocathode Cesium Telluride Nb(degrees) Cooled to 4 K. Undercoupled Frequency: ~1301.5727 MHz, Loaded Q:~1x107-Contaminants effect? Freq. Vs

  11. Si-based RF MEMS components.

    SciTech Connect (OSTI)

    Stevens, James E.; Nordquist, Christopher Daniel; Baker, Michael Sean; Fleming, James Grant; Stewart, Harold D.; Dyck, Christopher William

    2005-01-01T23:59:59.000Z

    Radio frequency microelectromechanical systems (RF MEMS) are an enabling technology for next-generation communications and radar systems in both military and commercial sectors. RF MEMS-based reconfigurable circuits outperform solid-state circuits in terms of insertion loss, linearity, and static power consumption and are advantageous in applications where high signal power and nanosecond switching speeds are not required. We have demonstrated a number of RF MEMS switches on high-resistivity silicon (high-R Si) that were fabricated by leveraging the volume manufacturing processes available in the Microelectronics Development Laboratory (MDL), a Class-1, radiation-hardened CMOS manufacturing facility. We describe novel tungsten and aluminum-based processes, and present results of switches developed in each of these processes. Series and shunt ohmic switches and shunt capacitive switches were successfully demonstrated. The implications of fabricating on high-R Si and suggested future directions for developing low-loss RF MEMS-based circuits are also discussed.

  12. Deeply scaled CMOS for RF power applications

    E-Print Network [OSTI]

    Scholvin, Jörg, 1976-

    2006-01-01T23:59:59.000Z

    The microelectronics industry is striving to reduce the cost, complexity, and form factor of wireless systems through single-chip integration of analog, RF and digital functions. Driven by the requirements of the digital ...

  13. Monolithic RF frontends for ubiquitous wireless connectivity

    E-Print Network [OSTI]

    Goswami, Sushmit

    2014-01-01T23:59:59.000Z

    The desire for ubiquitous connectivity is pushing radios towards highly-integrated, multi-standard and multi-band implementations. This thesis explores architectures for next-generation RF frontends, which form the interface ...

  14. Samsung: ENERGY STAR Referral (RF26VAB)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Samsung refrigerator-freezer model RF26VAB to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  15. EXPERIMENTAL STUDIES OF RF BREAKDOWNS IN THE COUPLER OF THE TTF RF GUN

    E-Print Network [OSTI]

    to han- dle 800 µs long RF pulses with 4.5 MW of peak power and at 10 Hz repetition rate. In this regime

  16. Ionizing wave via high-power HF acceleration

    E-Print Network [OSTI]

    Mishin, Evgeny

    2010-01-01T23:59:59.000Z

    Recent ionospheric modification experiments with the 3.6 MW transmitter at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska led to discovery of artificial ionization descending from the nominal interaction altitude in the background F-region ionosphere by ~60 km. This paper presents a physical model of an ionizing wavefront created by suprathermal electrons accelerated by the HF-excited plasma turbulence.

  17. Wideband high efficiency CMOS envelope amplifiers for 4G LTE handset envelope tracking RF power amplifiers

    E-Print Network [OSTI]

    Hassan, Muhammad

    2012-01-01T23:59:59.000Z

    RF power amplifier applications," IEEE Journal of Solid-RF power amplifier applications," IEEE Journal of Solid-RF power amplifier applications," IEEE Journal of Solid-

  18. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    SciTech Connect (OSTI)

    Johnson, Rolland

    2014-09-21T23:59:59.000Z

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.

  19. Compression mode resonances in Zr-90

    E-Print Network [OSTI]

    Youngblood, David H.; Lui, YW; John, B.; Tokimoto, Y.; Clark, HL; Chen, X.

    2004-01-01T23:59:59.000Z

    Compression mode resonances in 90Zr D. H. Youngblood, Y.-W. Lui, B. John,* Y. Tokimoto, H. L. Clark, and X. Chen Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA (Received 18 February 2004; published 20 May 2004..., JOHN, TOKIMOTO, CLARK, AND CHEN PHYSICAL REVIEW C 69, 054312 (2004) 054312-2 Fig. 2. The continuum distributions are similar over the en- tire energy range, whereas the angular distributions of the cross sections for the peak change...

  20. Evolution of E2 transition strength in deformed hafnium isotopes from new measurements on $^{172}$Hf, $^{174}$Hf, and $^{176}$Hf

    E-Print Network [OSTI]

    M. Rudigier; K. Nomura; M. Dannhoff; R-B. Gerst; J. Jolie; N. Saed-Samii; S. Stegemann; J-M. Régis; L. M. Robledo; R. Rodríguez-Guzmán; A. Blazhev; Ch. Fransen; N. Warr; K. O. Zell

    2015-04-07T23:59:59.000Z

    The available data for E2 transition strengths in the region between neutron-deficient Hf and Pt isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf. We remeasure the 2^+_1 half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. The half-lives were measured using \\gamma-\\gamma and conversion-electron-\\gamma delayed coincidences with the fast timing method. For the determination of half-lives in the picosecond region, the generalized centroid difference method was applied. For the theoretical calculation of the spectroscopic properties, the interacting boson model is employed, whose Hamiltonian is determined based on microscopic energy-density functional calculations. The measured 2^+_1 half-lives disagree with results from earlier \\gamma-\\gamma fast timing measurements, but are in agreement with data from Coulomb excitation experiments and other methods. Half-lives of the 4^+_1 and 6^+_1 states were measured, as well as a lower limit for the 8^+_1 states. We show the importance of the mass-dependence of effective boson charge in the description of E2 transition rates in chains of nuclei. It encourages further studies of the microscopic origin of this mass dependence. New data on transition rates in nuclei from neighboring isotopic chains could support these studies.

  1. Characterization of Zr-Fe-Cu Alloys for an Inert Matrix Fuel for Nuclear Energy Applications 

    E-Print Network [OSTI]

    Barnhart, Brian A.

    2013-08-09T23:59:59.000Z

    distinct phase morphologies. The top half of the sample was Zr rich and contained Zr precipitates dispersed in a matrix of intermetallic compounds while the bottom half consisted solely of intermetallic compounds. The third alloy, Zr-12Fe-15Cu...

  2. RF design of X-band RF deflector for femtosecond diagnostics of LCLS electron beam

    SciTech Connect (OSTI)

    Dolgashev, Valery A.; Wang Juwen [SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 (United States)

    2012-12-21T23:59:59.000Z

    We designed a successful constant impedance traveling wave X-band rf deflector for electron beam diagnostics at the 14 GeV SLAC Linac Coherent Light Source (LCLS). This is the first practical deflector built with a waveguide coupler. The 1-meter rf deflector produces 24 MeV peak transverse kick when powered with 20 MW of 11.424 GHz rf. The design is based on our experience with high gradient X-band accelerating structures. Several deflectors of this design have been built at SLAC and are currently in use. Here we describe the design and distinguishing features of this device.

  3. Investigation of Zr-C, Zr-N, and Potential Agostic Interactions in an Organozirconium Complex by Experimental

    E-Print Network [OSTI]

    Coppens, Philip

    fragment (Zr-C ) 2.43(5) Å), and the amide nitrogen atom (Zr-N ) 2.0312(5) Å) of the second ligand to titanium,1 and agostic interactions have been proposed on the basis of lengthened C-C bonds, dramati- cally.87(4)°, as compared to a value of 130.4(4)° in a similar titanium complex.6 Although a (C-H), ,,Zr interaction

  4. Design and fabrication of an RF power LDMOSFET on SOI

    E-Print Network [OSTI]

    Fiorenza, James G. (James George), 1972-

    2002-01-01T23:59:59.000Z

    This thesis studied thin-film Silicon-on-Insulator (SOI) LDMOSFET technology for RF power amplifier applications. To conduct this study, two generations of SOI RF power devices for portable wireless systems were designed ...

  5. analog rf gap: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LHC, particles not captured by the RF system at injection or leaking out of the RF bucket may quench the superconducting magnets during beam abort. The problem, common to other...

  6. Novel rf mems tunable filters with adjustable spurious suppression 

    E-Print Network [OSTI]

    Sekar, Vikram

    2009-05-15T23:59:59.000Z

    This thesis presents the theory and design of fixed and Radio Frequency (RF) Microelectromechanical Systems (MEMS) -based tunable microwave filters for RF and microwave applications. The methodology for the design of coupled resonator filters...

  7. Novel rf mems tunable filters with adjustable spurious suppression

    E-Print Network [OSTI]

    Sekar, Vikram

    2009-05-15T23:59:59.000Z

    This thesis presents the theory and design of fixed and Radio Frequency (RF) Microelectromechanical Systems (MEMS) -based tunable microwave filters for RF and microwave applications. The methodology for the design of coupled resonator filters...

  8. Survey reveals nature of corrosion in HF alky units

    SciTech Connect (OSTI)

    Dobis, J.D. (BP Oil Co., Marcus Hook, PA (United States)); Clarida, D.R. (Conoco Inc., Ponca City, OK (United States)); Richert, J.P. (Saudi Aramco/Mobil, Yanbu (Saudi Arabia))

    1995-03-06T23:59:59.000Z

    The results of a National Association of Corrosion Engineers survey of 62 HF alkylation units reveal relatively low incidence of service-related cracking of carbon steel. Hydrogen blistering, however, is prevalent, especially in the main acid circuit and overhead condensers. Based on these and other survey results, several recommendations are made to enable refiners to monitor and reduce corrosion in these special units. The paper discusses the survey results, construction materials, post-weld heat treatments, small-diameter piping, construction inspection, bolting, gaskets, block valves, maintenance practices, cracking, blistering, areas of vulnerability, and recommendations.

  9. Elevated temperature ablation resistance of HfC particle-reinforced tungsten composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    and spark plasma sintering (SPS) process. HfC was chos Keywords: Composite materials Powder metallurgy Sintering Ablation properties Microstructure The effects

  10. Configurations for short period rf undulators

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kuzikov, S. V.; Jiang, Y.; Marshall, T. C.; Sotnikov, G. V.; Hirshfield, J. L.

    2013-07-01T23:59:59.000Z

    Several configurations for rf undulators energized at millimeter wavelengths and designed to produce coherent nanometer radiation from sub-GeV electron beams are analyzed and compared with one another. These configurations include a traveling-wave resonant ring, a standing wave resonator, and a resonator operating close to cutoff.

  11. RF Breakdown of Metallic Surfaces in Hydrogen

    SciTech Connect (OSTI)

    BastaniNejad, M.; Elmustafa, A.A.; /Old Dominion U.; Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia

    2009-05-01T23:59:59.000Z

    In earlier reports, microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments were used to investigate the mechanism of RF breakdown of tungsten, molybdenum, and beryllium electrode surfaces. Plots of remnants were consistent with the breakdown events being due to field emission, due to the quantum mechanical tunnelling of electrons through a barrier as described by Fowler and Nordheim. In the work described here, these studies have been extended to include tin, aluminium, and copper. Contamination of the surfaces, discovered after the experiments concluded, have cast some doubt on the proper qualities to assign to the metallic surfaces. However, two significant results are noted. First, the maximum stable RF gradient of contaminated copper electrodes is higher than for a clean surface. Second, the addition of as little as 0.01% of SF6 to the hydrogen gas increased the maximum stable gradient, which implies that models of RF breakdown in hydrogen gas will be important to the study of metallic breakdown.

  12. RF Design of the LCLS Gun

    SciTech Connect (OSTI)

    Limborg-Deprey, C

    2010-12-13T23:59:59.000Z

    Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell, and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee [2]. Files and reference documents are compiled in Section IV.

  13. Emittance control in rf cavities and solenoids

    E-Print Network [OSTI]

    Eshraqi, Mohammad; Lombardi, Alessandra M

    2009-01-01T23:59:59.000Z

    We study emittance growth for transport of uniform and Gaussian beams of particles in rf cavities and solenoids and show analytically its dependence on initial beam parameters. Analytical results are confirmed with simulation studies over a broad range of different initial beams.

  14. Experimental Study of RF Pulsed Heating

    SciTech Connect (OSTI)

    Laurent, Lisa; Tantawi, Sami; Dolgashev, Valery; Nantista, Christopher; /SLAC; Higashi, Yasuo; /KEK, Tsukuba; Aicheler, Markus; Heikkinen, Samuli; Wuensch, Walter; /CERN

    2011-11-04T23:59:59.000Z

    Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop(reg. sign), copper silver, and silver plated copper. The samples were exposed to different machining and heat treatment processes prior to rf processing. Each sample was tested to a peak pulsed heating temperature of approximately 110 C and remained at this temperature for approximately 10 x 10{sup 6} rf pulses. In general, the results showed the possibility of pushing the gradient limits due to pulsed heating fatigue by the use of copper zirconium and copper chromium alloys.

  15. Commissioning of the MICE RF System

    E-Print Network [OSTI]

    Moss, A.; Stanley, T.; White, C.; Ronald, K.; Whyte, C.G.; Dick, A.J.; Speirs, D.C.; Alsari, S.

    2014-01-01T23:59:59.000Z

    The Muon Ionisation Cooling Experiment (MICE) is being constructed at Rutherford Appleton Laboratory in the UK. The muon beam will be cooled using multiple hydrogen absorbers then reaccelerated using an RF cavity system operating at 201MHz. This paper describes recent progress in commissioning the amplifier systems at their design operation conditions, installation and operation as part of the MICE project.

  16. Advanced RF power sources for linacs

    SciTech Connect (OSTI)

    Wilson, P.B.

    1996-10-01T23:59:59.000Z

    In order to maintain a reasonable over-all length at high center-of-mass energy, the main linac of an electron-positron linear collider must operate at a high accelerating gradient. For copper (non-superconducting) accelerator structures, this implies a high peak power per unit length and a high peak power per RF source, assuming a limited number of discrete sources are used. To provide this power, a number of devices are currently under active development or conceptual consideration: conventional klystrons with multi-cavity output structures, gyroklystrons, magnicons, sheet-beam klystrons, multiple-beam klystrons and amplifiers based on the FEL principle. To enhance the peak power produced by an rf source, the SLED rf pulse compression scheme is currently in use on existing linacs, and new compression methods that produce a flatter output pulse are being considered for future linear colliders. This paper covers the present status and future outlook for the more important rf power sources and pulse compression systems. It should be noted that high gradient electron linacs have applications in addition to high-energy linear colliders; they can, for example, serve as compact injectors for FEL`s and storage rings.

  17. Cw rf operation of the FMIT RFQ

    SciTech Connect (OSTI)

    Fazio, M.V.; Brandeberry, F.E.

    1985-01-01T23:59:59.000Z

    The 80-MHz RFQ for the Fusion Materials Irradiation Test Facility prototype accelerator has been rf conditioned for cw operation to the design field level of 17.5 MV/m (1.68 x Kilpatrick limit). Experimental results and operating experience will be discussed.

  18. Interdiffusion between Zr Diffusion Barrier and U-Mo Alloy

    SciTech Connect (OSTI)

    K. Huang; Y. Park; Y. H. Sohn

    2012-12-01T23:59:59.000Z

    U-Mo alloys are being developed as low enrichment uranium fuels under the Reduced Enrichment for Research and Test Reactor (RERTR) program. Significant reactions have been observed between U-Mo fuels and Al or Al alloy matrix. Refractory metal Zr has been proposed as barrier material to reduce the interactions. In order to investigate the compatibility and barrier effects between U-Mo alloy and Zr, solid-to-solid U-10wt.%Mo vs. Zr diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 °C for various times. The microstructures and concentration profiles due to interdiffusion and reactions were examined via scanning electron microscopy and electron probe microanalysis, respectively. Intermetallic phase Mo2Zr was found at the interface and its population increased when annealing temperature decreased. Diffusion paths were also plotted on the U-Mo-Zr ternary phase diagrams with good consistency. The growth rate of interdiffusion zone between U-10wt.%Mo and Zr was also calculated under the assumption of parabolic diffusion, and was determined to be about 103 times lower than the growth rate of diffusional interaction layer found in diffusion couples U-10wt.%Mo vs. Al or Al-Si alloy. Other desirable physical properties of Zr as barrier material, such as neutron adsorption rate, melting point and thermal conductivity are presented as supplementary information to demonstrate the great potential of Zr as the diffusion barrier for U-Mo fuel systems in RERTR.

  19. Frequency and amplitude control for an experimental linac rf drive

    E-Print Network [OSTI]

    Atre, Mahesh Purushottam

    1992-01-01T23:59:59.000Z

    uses a RFQ accelerator/buncher to accelerate a beam of II ions. The 500 keV, 10 mA beam will require approximately 100 kW (peak) rf power at 473 MHz [2]. The basic layout of the linac system is illustrated in Fig. 1. The rf power source uses...-rod structure resonant at 473 MHz. ION SOURCE RF QUADRUPOLE BEAM HIGH POWER RF AMP AMPL CONTROL LOW POWER RF AMP OSC FREQ CONTROL SYSTEM Figure 1. The Experimental Linac System The oscillator uses a phase-locked loop for frequency control...

  20. A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films

    E-Print Network [OSTI]

    Adler, Joan

    composition of grain boundaries in polycrystalline diamond lms by transmission electron microscopy and highA Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Israel Yoel Koenka #12;A Study of the Grain Boundaries and Hydrogen in HF-CVD Diamond Films Research Thesis In partial fulllment

  1. ORIGINAL PAPER Zircon Hf isotope perspective on the origin of granitic rocks

    E-Print Network [OSTI]

    Siebel, Wolfgang

    Ó Springer-Verlag 2009 Abstract The petrogenetic potential of in situ laser ablation Hf isotope data Bohemian Massif Á Granitoid Á Hafnium isotopes Á Laser ablation ICP-MS Á Variscan Á Zircon Introduction the Hf isotopic composition of individual zircons in situ by laser ablation ICP-MS (Thirlwall and Walder

  2. Safety Slide 1 Hydrofluoric (HF) Acid Hazards http://www.emsworld.com/web/online/Education/Hydrofluoric-Acid-/5$12949

    E-Print Network [OSTI]

    Cohen, Robert E.

    Safety Slide 1 ­ Hydrofluoric (HF) Acid Hazards http://www.emsworld.com/web may be delayed for up to 24 hours, even with dilute solutions. HF burns affect deep tissue layers

  3. ILC RF System R and D

    SciTech Connect (OSTI)

    Adolphsen, Chris; /SLAC

    2012-07-03T23:59:59.000Z

    The Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system proposed for the ILC linacs. Current activities include the long-term evaluation of a 120 kV Marx Modulator driving a 10 MW Multi-Beam Klystron, design of a second-generation Marx Modulator, testing of a sheet-beam gun and beam transport system for a klystron, construction of an rf distribution system with remotely-adjustable power tapoffs, and development of a system to combine the power from many klystrons in low-loss circular waveguide where it would be tapped-off periodically to power groups of cavities. This paper surveys progress during the past few years.

  4. An Efficient RF Source for Jlab

    SciTech Connect (OSTI)

    Neubauer, M. [Muons, Inc.; Dudas, A. [Muons, Inc.; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB

    2013-12-01T23:59:59.000Z

    We propose the development of a highly reliable high efficiency RF source for JLAB with a lower lifetime cost operating at 80% efficiency with system operating costs of about 0.7M$/year for the 6 GeV machine. The design of the RF source will be based upon two injection locked magnetrons in a novel combining architecture for amplitude modulation and a cross field amplifier (CFA) as an output tube for the 12 GeV upgrade. A cost analysis including efficiency and reliability will be performed to determine the optimum system architecture. Several different system architectures will be designed and evaluated for a dual injection locked magnetron source using novel combining techniques and possibly a CFA as the output tube. A paper design for the 1497 MHz magnetron system will be completed. The optimum system architecture with all relevant specifications will be completed so that a prototype can be built.

  5. RUGGED CERAMIC WINDOW FOR RF APPLICATIONS

    SciTech Connect (OSTI)

    MIKE NEUBAUER

    2012-11-01T23:59:59.000Z

    High-current RF cavities that are needed for many accelerator applications are often limited by the power transmission capability of the pressure barriers (windows) that separate the cavity from the power source. Most efforts to improve RF window design have focused on alumina ceramic, the most popular historical choice, and have not taken advantage of new materials. Alternative window materials have been investigated using a novel Merit Factor comparison and likely candidates have been tested for the material properties which will enable construction in the self-matched window configuration. Window assemblies have also been modeled and fabricated using compressed window techniques which have proven to increase the power handling capability of waveguide windows. Candidate materials have been chosen to be used in fabricating a window for high power testing at Thomas Jefferson National Accelerator Facility.

  6. Introduction Final Cooling Channel -High Frequency RF

    E-Print Network [OSTI]

    McDonald, Kirk

    algorithms integration with G4BL on NERSC Integration of twiss calculations with G4BL & Optimization codes Calculation of twiss function inside absorber+RF 0 5 10 15 20 25 0 1 2 3 4 5 6 7 8 9 10 P[GeV/c] z [m] Bz P=0V/c P=0.127 GeV/c In order to match for the field flip one needs to be able to calculate twiss functions

  7. Radio frequency (RF) heated supersonic flow laboratory

    SciTech Connect (OSTI)

    Wantuck, P.; Watanabe, H.

    1990-01-01T23:59:59.000Z

    A unique supersonic flow apparatus which employs an inductively-coupled, radio frequency (RF) torch to supply high enthalpy source gas to the nozzle inlet is described. The main features of this system are the plasma tube, a cooled nozzle assembly, and a combustion/expansion chamber with a heat exchanger. A description of these components with current test data is presented. In addition, a discussion of anticipated experiments utilizing this system is included.

  8. RF Gun Photocathode Research at SLAC

    SciTech Connect (OSTI)

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16T23:59:59.000Z

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  9. Digital hf radar observations of equatorial spread-F

    SciTech Connect (OSTI)

    Argo, P.E.

    1984-01-01T23:59:59.000Z

    Modern digital ionosondes, with both direction finding and doppler capabilities can provide large scale pictures of the Spread-F irregularity regions. A morphological framework has been developed that allows interpretation of the hf radar data. A large scale irregularity structure is found to be nightward of the dusk terminator, stationary in the solar reference frame. As the plasma moves through this foehn-wall-like structure it descends, and irregularities may be generated. Localized upwellings, or bubbles, may be produced, and they drift with the background plasma. The spread-F irregularity region is found to be best characterized as a partly cloudy sky, due to the patchiness of the substructures. 13 references, 16 figures.

  10. Producing a compound Nucleus via Inelastic Scattering: The 90Zr(alpha,alpha')90Zr* Case

    SciTech Connect (OSTI)

    Escher, J E; Dietrich, F S

    2008-05-23T23:59:59.000Z

    In a Surrogate reaction a compound nucleus is produced via a direct reaction (pickup, stripping, or inelastic scattering). For a proper application of the Surrogate approach it is necessary to predict the resulting angular momentum and parity distribution in the compound nucleus. A model for determining these distributions is developed for the case of inelastic alpha scattering off a spherical nucleus. The focus is on obtaining a first, simple description of the direct-reaction process that produces the compound nucleus and on providing the basis for a more complete treatment of the problem. The approximations employed in the present description are discussed and the extensions required for a more rigorous treatment of the problem are outlined. To illustrate the formalism, an application to {sup 90}Zr({alpha},{alpha}{prime}){sup 90}Zr* is presented.

  11. Design and Manufacture of the RF Power Supply and RF Transmission Line for SANAEM Project Prometheus

    E-Print Network [OSTI]

    Turemen, G; Unel, G; Alacakir, A

    2015-01-01T23:59:59.000Z

    A 1-5 MeV proton beamline is being built by the Turkish Atomic Energy Authority in collaboration with a number of graduate students from different universities. The most important aspect of the project, is to acquire the design ability and manufacturing capability of all the components locally. SPP will be an accelerator and beam diagnostics test facility and it will also serve the detector development community with its low beam current. This paper discusses the design and construction of the RF power supply and the RF transmission line components such as its waveguide converters and its circulator.

  12. RF Gun cavities cooling regime study. K. Floettmann1

    E-Print Network [OSTI]

    RF power of Pa 68kW corre- sponds to a heat load of 300kW m . To remove such a high heat value from of RF fields in the cavity at an operating frequency is calculated in the usual way. The temperature) with the boundary condition at the RF cavity surface: kc(ngradT) = Ps, (2) where kc = 391 W m·K is the heat

  13. Towards forming-free resistive switching in oxygen engineered HfO{sub 2?x}

    SciTech Connect (OSTI)

    Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P.; Zaumseil, P.; Sowinska, M.; Walczyk, D. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Gloskovskii, A. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-02-10T23:59:59.000Z

    We have investigated the resistive switching behavior in stoichiometric HfO{sub 2} and oxygen-deficient HfO{sub 2?x} thin films grown on TiN electrodes using reactive molecular beam epitaxy. Oxygen defect states were controlled by the flow of oxygen radicals during thin film growth. Hard X-ray photoelectron spectroscopy confirmed the presence of sub-stoichiometric hafnium oxide and defect states near the Fermi level. The oxygen deficient HfO{sub 2?x} thin films show bipolar switching with an electroforming occurring at low voltages and low operating currents, paving the way for almost forming-free devices for low-power applications.

  14. argon rf plasma: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    you for being so encouraging, for listening to and understanding the woes of RF plasma research, and for being so friendly at conferences and in the hallways. Professor...

  15. Multi-Physics Analysis of the Fermilab Booster RF Cavity

    SciTech Connect (OSTI)

    Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.; /Fermilab

    2012-05-14T23:59:59.000Z

    After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.

  16. Investigation of Microscopic Materials Limitations of Superconducting RF Cavities

    SciTech Connect (OSTI)

    Anlage, Steven [University of Maryland

    2014-07-23T23:59:59.000Z

    The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.

  17. atmospheric rf device: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Tuners with Computationally Efficient Time of Technology, Atlanta, GA 30332 2 Raytheon Company, Tucson AZ, 85734 Abstract -- Modern RF-MEMS device design methods in which...

  18. Active high-power RF switch and pulse compression system

    DOE Patents [OSTI]

    Tantawi, Sami G. (San Mateo, CA); Ruth, Ronald D. (Woodside, CA); Zolotorev, Max (Mountain View, CA)

    1998-01-01T23:59:59.000Z

    A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

  19. Locking Lasers to RF in an Ultra Fast FEL

    E-Print Network [OSTI]

    Wilcox, R.

    2011-01-01T23:59:59.000Z

    Lasers to RF in an Ultrafast FEL R. B . Wilcox, G . Huang,the X-ray pulses from the FEL. The phase-locked loop on the

  20. A new microphonics measurement method for superconducting RF...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    new microphonics measurement method for superconducting RF cavities Re-direct Destination: Mechanical vibrations of the superconducting cavity, also known as microphonics, cause...

  1. Computer control of rf at SLAC

    SciTech Connect (OSTI)

    Schwarz, H.D.

    1985-03-01T23:59:59.000Z

    The Stanford Linear Accelerator is presently upgraded for the SLAC Linear Collider project. The energy is to be increased from approximately 31 GeV to 50 GeV. Two electron beams and one positron beam are to be accelerated with high demands on the quality of the beams. The beam specifications are shown. To meet these specifications, all parameters influencing the beams have to be under tight control and continuous surveillance. This task is accomplished by a new computer system implemented at SLAC which has, among many other functions, control over rf accelerating fields. 13 refs., 8 figs., 2 tabs.

  2. RF Micro Devices | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I GeothermalPotentialBiopowerSolidGenerationMethodInformationeNevada <REC SolarRFMD Jump to:RF Micro

  3. Sandia National Laboratories: RF & Photonics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiationImplementingnpitche Home AboutMeeting: ProgramFebruaryJunePowerProjectsQuantumRF

  4. Pulse-Density Modulation for RF Applications: The Radio-Frequency Power Amplifier (RF PA)

    E-Print Network [OSTI]

    Sanders, Seth

    . This enables complex digital processing and control of RF switching waveforms. Trends in processing speed demonstrates, techniques previously used for audio amplifiers, motor control, and power conversion may now generations of CMOS technology. We implement digital control of the carrier amplitude using pulse

  5. A Third-Generation Multicast Protocol for HF Wireless Networks Huiyan Zhang and Eric E. Johnson

    E-Print Network [OSTI]

    Johnson, Eric E.

    . Johnson Klipsch School of Electrical and Computer Engineering New Mexico State University ABSTRACT-to-point) channels. Unlike other wireless net- works, however, most or all member stations in an HF network

  6. LuHf isotope systematics of fossil biogenic apatite and their effects on geochronology

    E-Print Network [OSTI]

    Schöne, Bernd R.

    ) and argillaceous matrices with low permeability (oil shale of Messel, Germany; Posidonienschiefer of Holzmaden the Eifel, Germany. Low 176 Lu/177 Hf ratios in all materials from the Middle Eocene Messel oil shale (e

  7. Extremely high frequency RF effects on electronics.

    SciTech Connect (OSTI)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01T23:59:59.000Z

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  8. Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc

    SciTech Connect (OSTI)

    Yogodzinski, Gene; Vervoort, Jeffery; Brown, Shaun Tyler; Gerseny, Megan

    2010-08-29T23:59:59.000Z

    The Hf and Nd isotopic compositions of 71 Quaternary lavas collected from locations along the full length of the Aleutian island arc are used to constrain the sources of Aleutian magmas and to provide insight into the geochemical behavior of Nd and Hf and related elements in the Aleutian subduction-magmatic system. Isotopic compositions of Aleutian lavas fall approximately at the center of, and form a trend parallel to, the terrestrial Hf-Nd isotopic array with {var_epsilon}{sub Hf} of +12.0 to +15.5 and {var_epsilon}{sub Nd} of +6.5 to +10.5. Basalts, andesites, and dacites within volcanic centers or in nearby volcanoes generally all have similar isotopic compositions, indicating that there is little measurable effect of crustal or other lithospheric assimilation within the volcanic plumbing systems of Aleutian volcanoes. Hafnium isotopic compositions have a clear pattern of along-arc increase that is continuous from the eastern-most locations near Cold Bay to Piip Seamount in the western-most part of the arc. This pattern is interpreted to reflect a westward decrease in the subducted sediment component present in Aleutian lavas, reflecting progressively lower rates of subduction westward as well as decreasing availability of trench sediment. Binary bulk mixing models (sediment + peridotite) demonstrate that 1-2% of the Hf in Aleutian lavas is derived from subducted sediment, indicating that Hf is mobilized out of the subducted sediment with an efficiency that is similar to that of Sr, Pb and Nd. Low published solubility for Hf and Nd in aqueous subduction fluids lead us to conclude that these elements are mobilized out of the subducted component and transferred to the mantle wedge as bulk sediment or as a silicate melt. Neodymium isotopes also generally increase from east to west, but the pattern is absent in the eastern third of the arc, where the sediment flux is high and increases from east to west, due to the presence of abundant terrigenous sediment in the trench east of the Amlia Fracture Zone, which is being subducting beneath the arc at Seguam Island. Mixing trends between mantle wedge and sediment end members become flatter in Hf-Nd isotope space at locations further west along the arc, indicating that the sediment end member in the west has either higher Nd/Hf or is more radiogenic in Hf compared to Nd. This pattern is interpreted to reflect an increase in pelagic clay relative to the terrigenous subducted sedimentary component westward along the arc. Results of this study imply that Hf does not behave as a conservative element in the Aleutian subduction system, as has been proposed for some other arcs.

  9. RF Power Degradation of GaN High Electron Mobility Transistors

    E-Print Network [OSTI]

    Joh, Jungwoo

    We have developed a versatile methodology to systematically investigate the RF reliability of GaN High-Electron Mobility Transistors. Our technique utilizes RF and DC figures of merit to diagnose the degradation of RF ...

  10. COLLISIONLESS ELECTRON HEATING IN RF GAS DISCHARGES: I. QUASILINEAR THEORY

    E-Print Network [OSTI]

    Kaganovich, Igor

    COLLISIONLESS ELECTRON HEATING IN RF GAS DISCHARGES: I. QUASILINEAR THEORY Yu.M. Aliev1 , I an interest in mechanisms of electron heating and power deposition in the plasma main- tained by radio{frequency (rf) electric elds. A modern trend in plasma technology aims at decreasing the gas pressures down

  11. Cooling at the quantum limit and RF refrigeration

    E-Print Network [OSTI]

    Fominov, Yakov

    Cooling at the quantum limit and RF refrigeration Jukka Pekola Low Temperature Laboratory, Helsinki) Francesco Giazotto (SNS Pisa) Yuri Pashkin (NEC) #12;Outline Electronic refrigeration Classical vs quantum (electromagnetic) heat transport Cooling at the quantum limit: experiments RF refrigeration in a single

  12. IBM Systems and Technology IBM 7RF SOI

    E-Print Network [OSTI]

    switches, antenna tuners, low noise amplifiers and power amplifiers found in the front end of today distortion device (LowD) option: Boosts performance of the 7RF SOI offering and enables designers to further smartphone radio com- plexity with a silicon offering optimized for RF front-end applications Reduce area

  13. RF cavity using liquid dielectric for tuning and cooling

    DOE Patents [OSTI]

    Popovic, Milorad (Warrenville, IL); Johnson, Rolland P. (Newport News, VA)

    2012-04-17T23:59:59.000Z

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  14. RF-MEMS capacitive switches with high reliability

    DOE Patents [OSTI]

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03T23:59:59.000Z

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  15. Hydrogen-filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    CHARLES, Ankenbrandt

    2009-04-17T23:59:59.000Z

    Ionization cooling requires low-Z energy absorbers immersed in a strong magnetic field and high-gradient, large-aperture RF cavities to be able to cool a muon beam as quickly as the short muon lifetime requires. RF cavities that operate in vacuum are vulnerable to dark-current- generated breakdown, which is exacerbated by strong magnetic fields, and they require extra safety windows that degrade cooling, to separate RF regions from hydrogen energy absorbers. RF cavities pressurized with dense hydrogen gas will be developed that use the same gas volume to provide the energy absorber and the RF acceleration needed for ionization cooling. The breakdown suppression by the dense gas will allow the cavities to operate in strong magnetic fields. Measurements of the operation of such a cavity will be made as functions of external magnetic field and charged particle beam intensity and compared with models to understand the characteristics of this technology and to develop mitigating strategies if necessary.

  16. Proposal for high pressure RF cavity test in the MTA

    SciTech Connect (OSTI)

    Yonehara, K.; /Fermilab

    2010-09-01T23:59:59.000Z

    In order to demonstrate the feasibility of high pressure hydrogen gas filled RF (HPRF) cavities for muon ionization cooling, an HPRF cavity must be tested with a high intensity charged beam. When an HPRF cavity is irradiated with an intense beam each incident particle generates about 1000 electrons and ions per cubic centimeter in a high pressure cavity via ionization. These ionization electrons are influenced by the RF field and the RF quality factor goes down. This Q factor reduction will be a problem with a multi bunch beam, e.g., a muon beam for a muon collider consists of a 12 to 20 bunch train beam with 5 ns timing gap. Thus, the RF field must recover in few nano seconds. We propose to use a 400 MeV proton beam in the MTA and measure a beam loading effect in the HPRF cavity and study the recovery mechanism of the RF field.

  17. SUPERCONDUCTING RF-DIPOLE DEFLECTING AND CRABBING CAVITIES

    SciTech Connect (OSTI)

    Delayen, Jean [ODU, JLAB; De Silva, Paygalage Subashini [ODU, JLAB

    2013-09-01T23:59:59.000Z

    Recent interests in designing compact deflecting and crabbing structures for future accelerators and colliders have initiated the development of novel rf structures. The superconducting rf-dipole cavity is one of the first compact designs with attractive properties such as higher gradients, higher shunt impedance, the absence of lower order modes and widely separated higher order modes. Two rf-dipole designs of 400 MHz and 499 MHz have been designed, fabricated and tested as proof-of-principle designs of compact deflecting and crabbing cavities for the LHC high luminosity upgrade and Jefferson Lab 12 GeV upgrade. The first rf tests have been performed on the rf-dipole geometries at 4.2 K and 2.0 K in a vertical test assembly with excellent results. The cavities have achieved high gradients with high intrinsic quality factors, and multipacting levels were easily processed.

  18. The electrical and lumen output characteristics of an RF lamp

    SciTech Connect (OSTI)

    Alexandrovich, B.M.; Godyak, V.A.; Piejak, R.B. [Osram Sylvania Inc., Beverly, MA (United States)

    1996-12-31T23:59:59.000Z

    Low pressure rf discharges have been studied for over a century. Their first practical application for lighting was proposed by Tesla in 1891. Since then hundreds of patents have been published attempting to implement rf lighting. However, progress in understanding rf discharge phenomena (mostly driven by plasma processing needs) and dramatic improvement in the performance/cost ratio of rf power sources have recently opened the door for development of rf light sources. Today commercial inductively coupled electrodeless lamps are offered by Matsuhita, Philips and GE. In this work the authors present measurements of the electrical characteristics and lumen output from a 2.65 MHz driven inductively coupled light source. Measurements were made on a spherical lamp of 3.125 inch diameter with a re-entrant cavity that houses a cylindrical ferrite core around which is wrapped the primary coil.

  19. Upgrade of the cryogenic CERN RF test facility

    SciTech Connect (OSTI)

    Pirotte, O.; Benda, V.; Brunner, O.; Inglese, V.; Maesen, P.; Vullierme, B. [CERN - European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Koettig, T. [ESS - European Spallation Source, Box 176, 221 00 Lund (Sweden)

    2014-01-29T23:59:59.000Z

    With the large number of superconducting radiofrequency (RF) cryomodules to be tested for the former LEP and the present LHC accelerator a RF test facility was erected early in the 1990’s in the largest cryogenic test facility at CERN located at Point 18. This facility consisted of four vertical test stands for single cavities and originally one and then two horizontal test benches for RF cryomodules operating at 4.5 K in saturated helium. CERN is presently working on the upgrade of its accelerator infrastructure, which requires new superconducting cavities operating below 2 K in saturated superfluid helium. Consequently, the RF test facility has been renewed in order to allow efficient cavity and cryomodule tests in superfluid helium and to improve its thermal performances. The new RF test facility is described and its performances are presented.

  20. High-power RF testing of a 352-MHZ fast-ferrite RF cavity tuner at the Advanced Photon Source.

    SciTech Connect (OSTI)

    Horan, D.; Cherbak, E.; Accelerator Systems Division (APS)

    2006-01-01T23:59:59.000Z

    A 352-MHz fast-ferrite rf cavity tuner, manufactured by Advanced Ferrite Technology, was high-power tested on a single-cell copper rf cavity at the Advanced Photon Source. These tests measured the fast-ferrite tuner performance in terms of power handling capability, tuning bandwidth, tuning speed, stability, and rf losses. The test system comprises a single-cell copper rf cavity fitted with two identical coupling loops, one for input rf power and the other for coupling the fast-ferrite tuner to the cavity fields. The fast-ferrite tuner rf circuit consists of a cavity coupling loop, a 6-1/8-inch EIA coaxial line system with directional couplers, and an adjustable 360{sup o} mechanical phase shifter in series with the fast-ferrite tuner. A bipolar DC bias supply, controlled by a low-level rf cavity tuning loop consisting of an rf phase detector and a PID amplifier, is used to provide a variable bias current to the tuner ferrite material to maintain the test cavity at resonance. Losses in the fast-ferrite tuner are calculated from cooling water calorimetry. Test data will be presented.

  1. LHC RF System Time-Domain Simulation

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14T23:59:59.000Z

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  2. ccsd00001116 Nucleation of Al 3 Zr and Al 3 Sc in aluminum alloys

    E-Print Network [OSTI]

    ccsd­00001116 (version 1) : 4 Feb 2004 Nucleation of Al 3 Zr and Al 3 Sc in aluminum alloys: from 4, 2004) Zr and Sc precipitate in aluminum alloys to form the compounds Al3Zr and Al3Sc which

  3. Transformation plasticity and thermoelastic behavior in ZrO2-containing ceramics

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    565 Transformation plasticity and thermoelastic behavior in ZrO2-containing ceramics A. H. Heuer plasticity in Zr02-containing ceramics. The trans thermoélastique. Abstract.- Transformation plasticity in ZrO2, which is responsible for the high strength and high

  4. Characterization of an RF plasma ion source for ion implantation

    SciTech Connect (OSTI)

    Kopalidis, Peter M.; Wan Zhimin [Advanced Ion Beam Technology Inc., 47370 Fremont Blvd., Fremont, CA 94538 (United States)

    2012-11-06T23:59:59.000Z

    A novel inductively coupled RF plasma ion source has been developed for use in a beamline ion implanter. Ion density data have been taken with an array of four Langmuir probes spaced equally at the source extraction arc slit. These provide ion density uniformity information as a function of source pressure, RF power and gas mixture composition. In addition, total extracted ion beam current data are presented for the same conditions. The comparative advantages of the RF source in terms of higher beam current, reduced maintenance and overall productivity improvement compared to a hot cathode source are discussed.

  5. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect (OSTI)

    Qian, Di; Bottomley, Paul A. [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); El-Sharkawy, AbdEl-Monem M.; Edelstein, William A., E-mail: w.edelstein@gmail.com [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ?3%. With the torso landmarked at the xiphoid, human adult whole?body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.

  6. Communication methods, systems, apparatus, and devices involving RF tag registration

    DOE Patents [OSTI]

    Burghard, Brion J. (W. Richland, WA); Skorpik, James R. (Kennewick, WA)

    2008-04-22T23:59:59.000Z

    One technique of the present invention includes a number of Radio Frequency (RF) tags that each have a different identifier. Information is broadcast to the tags from an RF tag interrogator. This information corresponds to a maximum quantity of tag response time slots that are available. This maximum quantity may be less than the total number of tags. The tags each select one of the time slots as a function of the information and a random number provided by each respective tag. The different identifiers are transmitted to the interrogator from at least a subset of the RF tags.

  7. Stability of barrier buckets with zero RF-barrier separations

    SciTech Connect (OSTI)

    Ng, K.Y.; /Fermilab

    2005-03-01T23:59:59.000Z

    A barrier bucket with very small separation between the rf barriers (relative to the barrier widths) or even zero separation has its synchrotron tune decreasing rather slowly from a large value towards the boundary of the bucket. As a result, large area at the bucket edges can become unstable under the modulation of rf voltage and/or rf phase. In addition, chaotic regions may form near the bucket center and extend outward under increasing modulation. Application is made to those barrier buckets used in the process of momentum mining at the Fermilab Recycler Ring.

  8. Design studies for the LCLS 120 Hz RF gun

    SciTech Connect (OSTI)

    Wang, X.J.; Babzien, M.; Ben-Zvi, I.; Chang, X.Y.; Pjerov, S.; Woodle, M.

    2000-11-01T23:59:59.000Z

    A preliminary design studies were carried out at Brookhaven National Laboratory for a photocathode RF gun injection system for LCLS 120 Hz operation. The starting point for the design is 50 Hz BNL Gun IV developed by a BNL/KEK/SHI collaboration. The basic parameters of the 120 Hz gun is discussed in this report. The complete photocathode RF gun injection system is described for a 120 Hz operation. The injector system includes photocathode RF gun, emittance compensation solenoid magnet, laser system and laser beam delivery system, and electron beam diagnostics. The basic design parameters, mechanical modification and the performance will be presented in this report.

  9. Determination of the chemistry of HF acidizing with the use of {sup 19}F NMR spectroscopy

    SciTech Connect (OSTI)

    Shuchart, C.E.; Buster, D.C.

    1995-11-01T23:59:59.000Z

    A more thorough understanding of the chemistry of HF acid and its reaction products on silica and alumino-silicates is essential to the design and optimization of HF acidizing treatments. To more clearly define the chemistry of HF acidizing, an in-depth investigation of the reaction of HF and H{sub 2}SiF{sub 6} with alumino-silicates was undertaken using {sup 19}F Nuclear Magnetic Resonance (NMR) spectroscopy. In addition to the fluosilicic acid (H{sub 2}SiF{sub 6}) and AlF{sup 2+} predicted by traditional theories, {sup 19}F NMR spectroscopy shows a complex mixture of silicon and aluminum fluoride species in reacted HF acidizing solutions. During a secondary reaction of silicon fluorides with alumino-silicates, a constant F/Al ratio was maintained until the silicon fluorides had reacted completely. The distribution of the fluoride species depends on the HCl concentration. In this investigation, a tertiary reaction of HF acid on alumino-silicates was identified. When the silicon fluorides have reacted completely to give silica gel, the aluminum fluoride complexes continue to react on fresh alumino-silicates. The reaction causes the aluminum content to increase and the F/Al ratio and acid concentration to decrease. The final F/Al ratio is dependent upon acid strength and temperature. Numerous HF acidizing well returns have been analyzed to verify the reactions conducted in the laboratory. The extent of the reaction of HF acid can be determined with the use of {sup 19}F NMR spectroscopy. In wells with temperatures of 150 to 200 F, the reaction of H{sub 2}SiF{sub 6} is complete. Silicon content was quite low, and pH levels were 2 to 3. The F/Al ratios of the returns were 0.5 to 1.3, depending on the concentration of HCl and HF used in the treatment. In wells less than 100 F, the secondary reaction did not go to completion. Silicon and aluminum fluoride complexes were present in the returns along with live HCl.

  10. Characteristics of Hf-silicate thin films synthesized by plasma enhanced atomic layer deposition

    SciTech Connect (OSTI)

    Liu Jiurong; Martin, Ryan M.; Chang, Jane P. [Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095 (United States)

    2008-09-15T23:59:59.000Z

    Hafnium silicate films were grown by alternating the deposition cycles of hafnium oxide and silicon oxide using a plasma enhanced atomic layer deposition process. The as-deposited and 900 deg. C annealed hafnium silicate films were determined to be amorphous using grazing incidence x-ray diffraction. This suggested that the formation of hafnium silicate suppressed the crystallization of HfO{sub 2} at high temperatures. The dielectric constants increased from {approx}5 to {approx}17 as the hafnium content increased from 9 to 17 at. % in the hafnium silicate films. The leakage currents through the Hf-rich Hf-silicate films were two to three orders of magnitude lower than that of SiO{sub 2} with the same equivalent oxide thickness in the range of 1.6-2.3 nm. The estimated band gap of Hf-silicate films from the O 1s plasma loss spectra increased with the increasing Si content due to the higher band gap of SiO{sub 2} than that of HfO{sub 2}.

  11. The Development of the Electrically Controlled High Power RF Switch and Its Application to Active RF Pulse Compression Systems

    SciTech Connect (OSTI)

    Guo, Jiquan; /SLAC

    2009-03-20T23:59:59.000Z

    In the past decades, there has been increasing interest in pulsed high power RF sources for building high-gradient high-energy particle accelerators. Passive RF pulse compression systems have been used in many applications to match the available RF sources to the loads requiring higher RF power but a shorter pulse. Theoretically, an active RF pulse compression system has the advantage of higher efficiency and compactness over the passive system. However, the key component for such a system an element capable of switching hundreds of megawatts of RF power in a short time compared to the compressed pulse width is still an open problem. In this dissertation, we present a switch module composed of an active window based on the bulk effects in semiconductor, a circular waveguide three-port network and a movable short plane, with the capability to adjust the S-parameters before and after switching. The RF properties of the switch module were analyzed. We give the scaling laws of the multiple-element switch systems, which allow the expansion of the system to a higher power level. We present a novel overmoded design for the circular waveguide three-port network and the associated circular-to-rectangular mode-converter. We also detail the design and synthesis process of this novel mode-converter. We demonstrate an electrically controlled ultra-fast high power X-band RF active window built with PIN diodes on high resistivity silicon. The window is capable of handling multi-megawatt RF power and can switch in 2-300ns with a 1000A current driver. A low power active pulse compression experiment was carried out with the switch module and a 375ns resonant delay line, obtaining 8 times compression gain with a compression ratio of 20.

  12. Recent Progress of RF Cavity Study at Mucool Test Area

    SciTech Connect (OSTI)

    Yonehara, Katsuya; /Fermilab

    2011-12-02T23:59:59.000Z

    Summar of presentation is: (1) MTA is a multi task working space to investigate RF cavities for R&D of muon beam cooling channel - (a) Intense 400 MeV H{sup -} beam, (b) Handle hydrogen (flammable) gas, (c) 5 Tesla SC solenoid magnet, (d) He cryogenic/recycling system; (2) Pillbox cavity has been refurbished to search better RF material - Beryllium button test will be happened soon; (3) E x B effect has been tested in a box cavity - Under study (result seems not to be desirable); (4) 201 MHz RF cavity with SRF cavity treatment has been tested at low magnetic field - (a) Observed some B field effect on maximum field gradient and (b) Further study is needed (large bore SC magnet will be delivered end of 2011); and (5) HPRF cavity beam test has started - (a) No RF breakdown observed and (b) Design a new HPRF cavity to investigate more plasma loading effect.

  13. Electrodeless lighting RF power source development. Final report

    SciTech Connect (OSTI)

    NONE

    1996-08-30T23:59:59.000Z

    An efficient, solid state RF power source has been developed on this NICE project for exciting low power electrodeless lamp bulbs. This project takes full advantage of concurrent advances in electrodeless lamp technology. Electrodeless lamp lighting systems utilizing the sulfur based bulb type developed by Fusion Lighting, Inc., is an emerging technology which is based on generating light in a confined plasma created and sustained by RF excitation. The bulb for such a lamp is filled with a particular element and inert gas at low pressure when cold. RF power from the RF source creates a plasma within the bulb which reaches temperatures approaching those of high pressure discharge lamp plasmas. At these temperatures the plasma radiates substantial visible light with a spectrum similar to sunlight.

  14. accelerating rf station: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    designed as 450 Omega . The RF power is fed by 1 kW solid state amplifier using a step-up transformer with 1:9 impedance ratio. In the high power test, an accelerating gap voltage...

  15. RF Thermal Plasma Synthesis of Ferrite Nanopowders from Metallurgical Wastes

    E-Print Network [OSTI]

    Gubicza, Jenõ

    that of ferrites synthesized by the conventional ceramic route. Introduction Radiofrequency (RF) thermal plasmas by X-ray diffraction (XRD) using a Philips Xpert diffractometer and CuK radiation (=0.15418 nm

  16. Rf System Requirements for JLab’s MEIC Collider Ring

    SciTech Connect (OSTI)

    Wang, Shaoheng [JLAB; Li, Rui [JLAB; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB; Zhang, Yuhong [JLAB

    2013-06-01T23:59:59.000Z

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. At the top energy are the electron and ion collider rings. For the ion ring, it accelerates five long ion bunches to colliding energy and rebunches ions into a train of very short bunches before colliding. A set of low frequency RF system is needed for the long ion bunch energy ramping. Another set of high frequency RF cavities is needed to rebunch ions. For the electron ring, superconducting RF (SRF) cavities are needed to compensate the synchrotron radiation energy loss. The impedance of the SRF cavities must be low enough to keep the high current electron beam stable. The preliminary design requirements of these RF cavities are presented.

  17. RF Sputtering for preparing substantially pure amorphous silicon monohydride

    DOE Patents [OSTI]

    Jeffrey, Frank R. (Ames, IA); Shanks, Howard R. (Ames, IA)

    1982-10-12T23:59:59.000Z

    A process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous silicon hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

  18. BN/Graphene/BN Transistors for RF Applications

    E-Print Network [OSTI]

    Taychatanapat, Thiti

    In this letter, we demonstrate the first BN/graphene/BN field-effect transistor for RF applications. This device structure can preserve the high mobility and the high carrier velocity of graphene, even when it is sandwiched ...

  19. Printed Low Power Amperometric Gas Sensors Employing RF Energy Harvesting

    E-Print Network [OSTI]

    Hochberg, Michael

    Printed Low Power Amperometric Gas Sensors Employing RF Energy Harvesting M. T. Cartera , J. R Seattle, WA 98195-2350, USA We will report on some new types of low power amperometric gas sensors

  20. Electrical degradation mechanisms of RF power GaAs PHEMTs

    E-Print Network [OSTI]

    Villanueva, Anita A. (Anita Ariel), 1978-

    2007-01-01T23:59:59.000Z

    GaAs Pseudomorphic High-Electron Mobility Transistors (PHEMTs) are widely used in RF power applications. Since these devices typically operate at high power levels and under high voltage biasing, their electrical reliability ...

  1. CMOS RF Power Amplifier Design for Wireless Communications

    E-Print Network [OSTI]

    FANG, Qiang

    2012-01-01T23:59:59.000Z

    conjugate (S22) match (solid curve) and power match (dashedSupply Linear RF Power Amplifier", IEEE J. Solid-State Circ.Fully-integrated CMOS Power Amplifiers", IEEE J. Solid-State

  2. Progress on the Mice 201 MNz RF Cavity at LBNL

    E-Print Network [OSTI]

    Luo, Tianhuan

    2014-01-01T23:59:59.000Z

    like to thank people at LBNL EH&S and Main Machine Shop forMICE 201 MHz RF CAVITY AT LBNL* Tianhuan Luol, Don Summers,Virostek, Michael Zisman, LBNL, Berkeley, CA 94720, USA

  3. DESIGN OF A DC/RF PHOTOELECTRON GUN.

    SciTech Connect (OSTI)

    YU,D.NEWSHAM,Y.SMIRONOV,A.YU,J.SMEDLEY,J.SRINIVASAN RAU,T.LEWELLEN,J.ZHOLENTS,A.

    2003-05-12T23:59:59.000Z

    An integrated dc/rf photoelectron gun produces a low-emittance beam by first rapidly accelerating electrons at a high gradient during a short ({approx}1 ns), high-voltage pulse, and then injecting the electrons into an rf cavity for subsequent acceleration. Simulations show that significant improvement of the emittance appears when a high field ({approx} 0.5-1 GV/m) is applied to the cathode surface. An adjustable dc gap ({le} 1 mm) which can be integrated with an rf cavity is designed for initial testing at the Injector Test Stand at Argonne National Laboratory using an existing 70-kV pulse generator. Plans for additional experiments of an integrated dc/rf gun with a 250-kV pulse generator are being made.

  4. RF Pulse Design for Parallel Excitation in Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Liu, Yinan

    2012-07-16T23:59:59.000Z

    , such as accelerating imaging speed, mitigating field inhomogeneity in high-field MRI, and alleviating the susceptibility artifact in functional MRI (fMRI). In these applications, controlling radiofrequency (RF) power deposition (quantified by Specific Absorption Rate...

  5. RF-MEMS Switched Varactors for Medium Power Applications

    E-Print Network [OSTI]

    Maury, F; Crunteanu, A; Conseil, F; Blondy, P

    2008-01-01T23:59:59.000Z

    In RF (Radio Frequency) domain, one of the limitations of using MEMS (Micro Electromechanical Systems) switching devices for medium power applications is RF power. Failure phenomena appear even for 500 mW. A design of MEMS switched capacitors with an enhanced topology is presented in this paper to prevent it. This kind of device and its promising performances will serve to fabricate a MEMS based phase shifter able to work under several watts.

  6. Measurement of current distribution on RF coils using MR imaging 

    E-Print Network [OSTI]

    Wu, Yu

    1993-01-01T23:59:59.000Z

    MEASUREMENT OF CURRENT DISTRIBUTION ON RF COILS USING MR IMAGING A Thesis by YU WU Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December... 1993 Major Subject' Electrical Engineering MEASUREMENT OF CURRENT DISTRIBUTION ON RF COILS USING MR IMAGING A Thesis by YU WU Submitted to Texas ASM University in partial fulfillment of the requirments for the degree of MASTER OF SCIENCE...

  7. Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses

    E-Print Network [OSTI]

    Zheng, Yufeng

    Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic June 2010 The corrosion properties of two Zr-based bulk metallic glass, Zr41Ti14Cu12Ni10Be23 LM1 and Zr potential, LM1b showed superior corrosion resistance to LM1. Under identical sample preparation and testing

  8. Spatially-resolved EELS and EDS Analysis of HfOxNy Gate Dielectrics Deposited by MOCVD using [(C2H5)2N]4Hf with NO and O2

    E-Print Network [OSTI]

    Ng, Wai Tung

    -resolved electron energy loss spectroscopy (EELS) and energy-dispersive spectrometry (EDS). HfOxNy gate dielectrics a replacement for SiO2 as the gate dielectric material. HfO2 is a promising candidate due to its high dielectric constant its stability on Si. However, crystallization temperatures of less than 500 °C and high impurity

  9. COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS

    SciTech Connect (OSTI)

    Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

    2011-03-01T23:59:59.000Z

    The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

  10. High power RF systems for the BNL ERL project

    SciTech Connect (OSTI)

    Zaltsman, A.; Lambiase, R.

    2011-03-28T23:59:59.000Z

    The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

  11. R&D ERL: High power RF systems

    SciTech Connect (OSTI)

    Zaltsman, A.

    2010-01-15T23:59:59.000Z

    The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2.5 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.

  12. A New Environmentally Friendly AL/ZR-Based Clay Stabilizer

    E-Print Network [OSTI]

    El-Monier, Ilham Abdallah

    2013-01-18T23:59:59.000Z

    Clay stabilizers are means to prevent fines migration and clay swelling, which are caused by the contact of formation with low salinity or high pH brines at high temperature. Previous clay stabilizers including: Al and Zr compounds and cationic...

  13. Antiferromagnetism of perovskite EuZrO{sub 3}

    SciTech Connect (OSTI)

    Zong Yanhua [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Fujita, Koji, E-mail: fujita@dipole7.kuic.kyoto-u.ac.j [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Akamatsu, Hirofumi; Murai, Shunsuke; Tanaka, Katsuhisa [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2010-01-15T23:59:59.000Z

    Polycrystalline EuZrO{sub 3} has been synthesized by the solid-state reaction between EuO and ZrO{sub 2}, and its structural and magnetic properties have been investigated. Rietveld analysis of the X-ray diffraction pattern indicates that EuZrO{sub 3} crystallizes in an orthorhombic perovskite structure. {sup 151}Eu Moessbauer effect measurement reveals that almost all the europium ions are present as the divalent state and occupy distorted sites with non-axial electric field gradients, in agreement with the orthorhombic structure. In contrast to previous reports, an antiferromagnetic transition was observed around 4.1 K. The magnetic structure below the Neel temperature has been discussed. - Graphical abstract: Perovskite EuZrO{sub 3} with almost all Eu ions present as Eu{sup 2+} has been synthesized and its structure and magnetic properties have been studied. An antiferromagnetic transition was observed around 4.1 K for the first time. The mechanism of the magnetic transition has been discussed.

  14. Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line

    SciTech Connect (OSTI)

    Ma Wenchao [Department of Physics, Mississippi State University, Mississippi State, MS 39762 (United States)

    2012-10-20T23:59:59.000Z

    Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

  15. Hydrocarbon reaction with HF-cleaned Si(lOQ) and effects on metal-oxide-semiconductor device quality

    E-Print Network [OSTI]

    Rubloff, Gary W.

    Hydrocarbon reaction with HF-cleaned Si(lOQ) and effects on metal-oxide-semiconductor device-cleaned Si( 100) towards hydrocarbon adsorption is examined by surface analysis; most hydrocarbons adsorb oxidation after HF treatment.4'5 In this letter, passivation against hydrocarbon contamination is studied

  16. Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12T23:59:59.000Z

    by other means. We have used Equal Channel Angular Extrusion (ECAE), hot rolling and marforming to strengthen the 49.8Ni-42.2Ti-8Hf (in at. %) material and to introduce desired texture to overcome these problems in NiTiHf alloys. ECAE offers the advantage...

  17. Trapping in deep defects under substrate hot electron stress in TiN/Hf-silicate based gate stacks

    E-Print Network [OSTI]

    Misra, Durgamadhab "Durga"

    Trapping in deep defects under substrate hot electron stress in TiN/Hf-silicate based gate stacks N. Zaslavsky Abstract Substrate hot electron stress was applied on n+ -ringed n-channel MOS capacitors with TiN/Hf-silicate. Introduction Hafnium silicate based high-j gate dielectrics have been put forth as the leading candidates

  18. Point defect energetics in the ZrNi and Zr2Ni intermetallics C.S. Moura a,b

    E-Print Network [OSTI]

    Motta, Arthur T.

    and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USA c Materials Science-neighbor Zr atoms. Ã? 2001 Elsevier Science B.V. All rights reserved. 1. Introduction There has been great of these compounds is governed by the balance between the irradiation damage and the annealing response

  19. Crystallization of Zr2PdxCu(1-x) and Zr2NixCu(1-x) Metallic Glass

    SciTech Connect (OSTI)

    Min Xu

    2008-08-18T23:59:59.000Z

    One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction {HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr{sub 2}Pd{sub x}Cu{sub (1-x)} and Zr{sub 2}Ni{sub x}Cu{sub (1-x)} metallic glass have been explored. All Zr{sub 2}Pd{sub x}Cu{sub (1-x)} compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr{sub 2}Pd{sub x}Cu{sub (1·x)} system. Meta-stable C16 phase is competitive with C11b phase at x = 0.5, which is dominated by electronic structure rather than size effects. Cu-rich and Ni-rich compositions in Zr{sub 2}Ni{sub x}Cu{sub (1-x)} trend to divitrify to C11b or C16 phases respectively. In the proposed pseudo binary phase diagram, the domain of C16, C11b and co-existence phases are mainly related with the topology in the amorphous structure and formation enthalpies of crystalline phases.

  20. Precipitation in cold-rolled Al–Sc–Zr and Al–Mn–Sc–Zr alloys prepared by powder metallurgy

    SciTech Connect (OSTI)

    Vlach, M., E-mail: martin.vlach@mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, CZ-121 16 Prague (Czech Republic); Stulikova, I.; Smola, B.; Kekule, T.; Kudrnova, H.; Danis, S. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, CZ-121 16 Prague (Czech Republic); Gemma, R. [King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, 23955-6900 Thuwal (Saudi Arabia); Ocenasek, V. [SVÚM a.s., Podnikatelská 565, CZ-190 11 Prague (Czech Republic); Malek, J. [Czech Technical University in Prague, Faculty of Mechanical Engineering, CZ-120 00 Prague (Czech Republic); Tanprayoon, D.; Neubert, V. [Institut für Materialprüfung und Werkstofftechnik, Freiberger Strasse 1, D-38678 Clausthal-Zellerfeld (Germany)

    2013-12-15T23:59:59.000Z

    The effects of cold-rolling on thermal, mechanical and electrical properties, microstructure and recrystallization behaviour of the AlScZr and AlMnScZr alloys prepared by powder metallurgy were studied. The powder was produced by atomising in argon with 1% oxygen and then consolidated by hot extrusion at 350 °C. The electrical resistometry and microhardness together with differential scanning calorimetry measurements were compared with microstructure development observed by transmission and scanning electron microscopy, X-ray diffraction and electron backscatter diffraction. Fine (sub)grain structure developed and fine coherent Al{sub 3}Sc and/or Al{sub 3}(Sc,Zr) particles precipitated during extrusion at 350 °C in the alloys studied. Additional precipitation of the Al{sub 3}Sc and/or Al{sub 3}(Sc,Zr) particles and/or their coarsening was slightly facilitated by the previous cold rolling. The presence of Sc,Zr-containing particles has a significant antirecrystallization effect that prevents recrystallization at temperatures minimally up to 420 °C. The precipitation of the Al{sub 6}Mn- and/or Al{sub 6}(Mn,Fe) particles of a size ? 1.0 ?m at subgrain boundaries has also an essential antirecrystallization effect and totally suppresses recrystallization during 32 h long annealing at 550 °C. The texture development of the alloys seems to be affected by high solid solution strengthening by Mn. The precipitation of the Mn-containing alloy is highly enhanced by a cold rolling. The apparent activation energy of the Al{sub 3}Sc particles formation and/or coarsening and that of the Al{sub 6}Mn and/or Al{sub 6}(Mn,Fe) particle precipitation in the powder and in the compacted alloys were determined. The cold deformation has no effect on the apparent activation energy values of the Al{sub 3}Sc-phase and the Al{sub 6}Mn-phase precipitation. - Highlights: • The Mn, Sc and Zr additions to Al totally suppresses recrystallization at 550 °C. • The Sc,Zr-containing particle precipitation is slightly facilitated by cold rolling. • The Mn-containing particle precipitation is highly enhanced by cold rolling. • Cold rolling has no effect on activation energy of the Al{sub 3}Sc and Al{sub 6}Mn precipitation. • The texture development is affected by high solid solution strengthening by Mn.

  1. RF-Plasma Source Commissioning in Indian Negative Ion Facility

    SciTech Connect (OSTI)

    Singh, M. J.; Bandyopadhyay, M.; Yadava, Ratnakar; Chakraborty, A. K. [ITER- India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujrat (India); Bansal, G.; Gahlaut, A.; Soni, J.; Kumar, Sunil; Pandya, K.; Parmar, K. G.; Sonara, J. [Institute for Plasma Research, Bhat Gandhinagar, Gujrat (India); Kraus, W.; Heinemann, B.; Riedl, R.; Obermayer, S.; Martens, C.; Franzen, P.; Fantz, U. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2011-09-26T23:59:59.000Z

    The Indian program of the RF based negative ion source has started off with the commissioning of ROBIN, the inductively coupled RF based negative ion source facility under establishment at Institute for Plasma research (IPR), India. The facility is being developed under a technology transfer agreement with IPP Garching. It consists of a single RF driver based beam source (BATMAN replica) coupled to a 100 kW, 1 MHz RF generator with a self excited oscillator, through a matching network, for plasma production and ion extraction and acceleration. The delivery of the RF generator and the RF plasma source without the accelerator, has enabled initiation of plasma production experiments. The recent experimental campaign has established the matching circuit parameters that result in plasma production with density in the range of 0.5-1x10{sup 18}/m{sup 3}, at operational gas pressures ranging between 0.4-1 Pa. Various configurations of the matching network have been experimented upon to obtain a stable operation of the set up for RF powers ranging between 25-85 kW and pulse lengths ranging between 4-20 s. It has been observed that the range of the parameters of the matching circuit, over which the frequency of the power supply is stable, is narrow and further experiments with increased number of turns in the coil are in the pipeline to see if the range can be widened. In this paper, the description of the experimental system and the commissioning data related to the optimisation of the various parameters of the matching network, to obtain stable plasma of required density, are presented and discussed.

  2. Comparison of S, Pt, and Hf adsorption on NiAl(110) Karin M. Carling a

    E-Print Network [OSTI]

    Carter, Emily A.

    Gunaydin b , Tracy A. Mitchell b , Emily A. Carter a,b,* a Department of Mechanical and Aerospace. Keywords: NiAl alloy; (110) surface; Adsorption; Hf; Pt; S; DFT 1. Introduction NiAl alloys alloys either contain primarily Ni, with Cr, Al, and Y do- pants [6­8], or are based on NiAlPt alloys [9

  3. Finland HF and Esrange MST radar observations of polar mesosphere summer echoes

    E-Print Network [OSTI]

    Kirkwood, Sheila

    , Neil F. Arnold2 , Sheila Kirkwood3 , Nozomu Nishitani1 , and Mark Lester2 1 Solar Ogawa1 , Neil F. Arnold2 , Sheila Kirkwood3 , Nozomu Nishitani1 , and Mark Lester2 1 Solar et al., 1997; Jenk- ins and Jarvis, 1999; Arnold et al., 2002). The first HF radar observations

  4. Performance of Routing Protocols in HF Wireless Networks Eric E. Johnson*

    E-Print Network [OSTI]

    Johnson, Eric E.

    Balakrishnan* , and Zibin Tang* Klipsch School of Electrical and Computer Engineering New Mexico State-line-of-sight wireless communications for de- fense, diplomatic, and commercial applications. HF net- works are often environmental ef- fects, leading to intermittent link outages and even net- work partitions. Thus an indirect

  5. Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: a case study

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    the transport of mass, energy, and momentum from the solar wind into the near-Earth environment, is facilitated with the CUTLASS Finland coherent HF radar, a meridian-scanning photometer located at Ny AÃ? lesund, Svalbard on the scale of minutes, and which are believed to be related to the dynamic nature of energy and momentum

  6. Oxygen diffusion and reactions in Hf-based dielectrics L. V. Goncharova,a

    E-Print Network [OSTI]

    Gustafsson, Torgny

    Oxygen diffusion and reactions in Hf-based dielectrics L. V. Goncharova,a M. Dalponte, D. G Oxygen transport in and reactions with thin hafnium oxide and hafnium silicate films have been. The exchange rate is faster for pure hafnium oxides than for silicates. The amount of exchanged oxygen

  7. A FUZZY GENETIC ALGORITHM FOR AUTOMATIC CHANNEL ASSIGNMENT FOR TACTICAL HF RADIO NETWORKS

    E-Print Network [OSTI]

    Kaminsky, Alan

    allocating chan- nels to groups of tactical HF radio nets is described. The method finds an optimal channel assignment that pro- vides good propagation for each net, as determined by propagation prediction models). Net Parameters. The radios are grouped into one or more networks, or nets. A particular radio can

  8. HF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System on Environment

    E-Print Network [OSTI]

    Boyer, Edmond

    Sea in the context of climate change and anthropogenic pressure and to supply and maintain longHF radar in French Mediterranean Sea: an element of MOOSE Mediterranean Ocean Observing System , Pascal Guterman2 , Karim Bernardet2 1 Mediterranean Institute of Oceanography (MIO, UM 110, USTV

  9. High Power RF Test Facility at the SNS

    SciTech Connect (OSTI)

    Y.W. Kang; D.E. Anderson; I.E. Campisi; M. Champion; M.T. Crofford; R.E. Fuja; P.A. Gurd; S. Hasan; K.-U. Kasemir; M.P. McCarthy; D. Stout; J.Y. Tang; A.V. Vassioutchenko; M. Wezensky; G.K. Davis; M. A. Drury; T. Powers; M. Stirbet

    2005-05-16T23:59:59.000Z

    RF Test Facility has been completed in the SNS project at ORNL to support test and conditioning operation of RF subsystems and components. The system consists of two transmitters for two klystrons powered by a common high voltage pulsed converter modulator that can provide power to two independent RF systems. The waveguides are configured with WR2100 and WR1150 sizes for presently used frequencies: 402.5 MHz and 805 MHz. Both 402.5 MHz and 805 MHz systems have circulator protected klystrons that can be powered by the modulator capable of delivering 11 MW peak and 1 MW average power. The facility has been equipped with computer control for various RF processing and complete dual frequency operation. More than forty 805 MHz fundamental power couplers for the SNS superconducting linac (SCL) cavities have been RF conditioned in this facility. The facility provides more than 1000 ft2 floor area for various test setups. The facility also has a shielded cave area that can support high power tests of normal conducting and superconducting accelerating cavities and components.

  10. RF Power Upgrade for CEBAF at Jefferson Laboratory

    SciTech Connect (OSTI)

    Andrew Kimber,Richard Nelson

    2011-03-01T23:59:59.000Z

    Jefferson Laboratory (JLab) is currently upgrading the 6GeV Continuous Electron Beam Accelerator Facility (CEBAF) to 12GeV. As part of the upgrade, RF systems will be added, bringing the total from 340 to 420. Existing RF systems can provide up to 6.5 kW of CW RF at 1497 MHZ. The 80 new systems will provide increased RF power of up to 13 kW CW each. Built around a newly designed and higher efficiency 13 kW klystron developed for JLab by L-3 Communications, each new RF chain is a completely revamped system using hardware different than our present installations. This paper will discuss the main components of the new systems including the 13 kW klystron, waveguide isolator, and HV power supply using switch-mode technology. Methodology for selection of the various components and results of initial testing will also be addressed. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

  11. 805 MHz and 201 MHz RF cavity development for MUCOOL

    SciTech Connect (OSTI)

    DLi@lbl.gov

    2002-10-10T23:59:59.000Z

    A muon cooling channel calls for very high acceleratinggradient RF structures to restore the energy lost by muons in theabsorbers. The RF structures have to be operated in a strong magneticfield and thus the use of superconducting RF cavities is excluded. Toachieve a high shunt impedance while maintaining a large enough apertureto accommodate a large transverse emittance muon beam, the cavity designadopted is a pillbox-like geometry with thin Be foils to terminate theelectromagnetic field at the cavity iris. The possibility of using gridsof thin-walled metallic tubes for the termination is also being explored.Many of the RF-related issues for muon cooling channels are being studiedboth theoretically and experimentally using an 805 MHz cavity that has apillbox-like geometry with thin Be windows to terminate the cavityaperture. The design and performance of this cavity are reported here.High-power RF tests of the 805 MHz cavity are in progress at Lab G inFermilab. The cavity has exceeded its design gradient of 30 MV/m,reaching 34 MV/m without external magnetic field. No surface damage wasobserved at this gradient. The cavity is currently under conditioning atLab G with an external magnetic field of 2.5 T. We also present here a201 MHz cavity design for muoncooling channels. The proposed cavitydesign is also suitable for use in a proof-of-principle Muon IonizationCooling Experiment (MICE).

  12. RF Pulse compression stabilization at the CTF3 CLIC test facility

    E-Print Network [OSTI]

    Dubrovskiy, Alexey

    2010-01-01T23:59:59.000Z

    In the CTF3 accelerator, the RF produced by each of ten 3 GHz klystrons goes through waveguides, RF pulse compressors and splitters. The RF phase and power transformation of these devices depend on their temperature. The quantitative effect of the room temperature variation on the RF was measured. It is the major source of undesired changes during the CTF3 operation. An RF phaseloop and a compressor temperature stabilization are developed to suppress the phase fluctuation and the power profile change due to the temperature variation. The implementation is transparent for operators, it does not limit anyhow the flexibility of RF manipulations. Expected and measured suppression characteristics will be given.

  13. A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry

    E-Print Network [OSTI]

    Sonnentrucker, P; Neufeld, D A; Flagey, N; Gerin, M; Goldsmith, P; Lis, D; Monje, R

    2015-01-01T23:59:59.000Z

    We combine Herschel observations of a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the Heterodyne Instrument for the Far-Infrared (HIFI) allows us to compare the HF and H2O distributions in 47 diffuse cloud components sampling the disk. We find that the HF and H2O velocity distributions follow each other almost perfectly and establish that HF and H2O probe the same gas-phase volume. Our observations corroborate theoretical predictions that HF is a sensitive tracer of H2 in diffuse clouds, down to molecular fractions of only a few percent. Using HF to trace H2 in our sample, we find that the N(H2O)-to-N(HF) ratio shows a narrow distribution with a median value of 1.51. Our results further suggest that H2O might be used as a tracer of H2 -within a factor 2.5- in the diffuse interstellar medium. We show that the measured factor of ~2.5 variation around the median is dri...

  14. Feed forward rf control system of the accelerator test facility

    SciTech Connect (OSTI)

    Ben-Zvi, I.; Xie, Jialin; Zhang, Renshan.

    1991-01-01T23:59:59.000Z

    We report a scheme to control the amplitude and phase of the rf accelerating field in a klystron driven electron linac. The amplitude and phase distribution within the rf pulse can be controlled to follow specified functions to reduce the energy spread of the electron beam being accelerated. The scheme employs fast beam energy and phase detectors and voltage-controlled electronic attenuator and phase shifter in the amplifier chain. The control voltages of these devices are generated by arbitrary function generators. The function generators' outputs are calculated numerically using an algorithm which takes into consideration the desired target function and the deviation (due to load variations or system parameter drift) from the target function. Results of preliminary tests on producing flat rf power and phase pulses from a high power klystron indicate that amplitude variation of {plus minus}0.2% and phase variation of {plus minus}1{degree} can be readily achieved. 4 refs., 3 figs.

  15. HOM Coupler Optimisation for the Superconducting RF Cavities in ESS

    E-Print Network [OSTI]

    Ainsworth, R; Calaga, R

    2012-01-01T23:59:59.000Z

    The European Spallation Source (ESS) will be the world’s most powerful next generation neutron source. It consists of a linear accelerator, target, and instruments for neutron experiments. The linac is designed to accelerate protons to a ?nal energy of 2.5 GeV, with an average design beam power of 5 MW, for collision with a target used to produce a high neutron ?ux. A section of the linac will contain Superconducting RF (SCRF) cavities designed at 704 MHz. Beam induced HOMs in these cavities may drive the beam unstable and increase the cryogenic load, therefore HOM couplers are installed to provide suf?cient damping. Previous studies have shown that these couplers are susceptible to multipacting, a resonant process which can absorb RF power and lead to heating effects. This paper will show how a coupler suffering from multipacting has been redesigned to limit this effect. Optimisation of the RF damping is also discussed.

  16. Theory and Practice of Cavity RF Test Systems

    SciTech Connect (OSTI)

    Tom Powers

    2006-08-28T23:59:59.000Z

    Over the years Jefferson Lab staff members have performed about 2500 cold cavity tests on about 500 different superconducting cavities. Most of these cavities were later installed in 73 different cryomodules, which were used in three different accelerators. All of the cavities were tested in our vertical test area. About 25% of the cryomodules were tested in our cryomodule test facility and later commissioned in an accelerator. The remainder of the cryomodules were tested and commissioned after they were installed in their respective accelerator. This paper is an overview which should provide a practical background in the RF systems used to test the cavities as well as provide the mathematics necessary to convert the raw pulsed or continuous wave RF signals into useful information such as gradient, quality factor, RF-heat loads and loaded Q?s. Additionally, I will provide the equations necessary for determining the measurement error associated with these values.

  17. A computer program for HVDC converter station RF noise calculations

    SciTech Connect (OSTI)

    Kasten, D.G.; Caldecott, R.; Sebo, S.A. (Ohio State Univ., Columbus, OH (United States). Dept. of Electrical Engineering); Liu, Y. (Virginia Polytechnic Inst. State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

    1994-04-01T23:59:59.000Z

    HVDC converter station operations generate radio frequency (RF) electromagnetic (EM) noise which could interfere with adjacent communication and computer equipment, and carrier system operations. A generic Radio Frequency Computer Analysis Program (RAFCAP) for calculating the EM noise generated by valve ignition of a converter station has been developed as part of a larger project. The program calculates RF voltages, currents, complex power, ground level electric field strength and magnetic flux density in and around an HVDC converter station. The program requires the converter station network to be represented by frequency dependent impedance functions. Comparisons of calculated and measured values are given for an actual HVDC station to illustrate the validity of the program. RAFCAP is designed to be used by engineers for the purpose of calculating the RF noise produced by the igniting of HVDC converter valves.

  18. Recent Progress of RF Cavity Study at Mucool Test Area

    E-Print Network [OSTI]

    Yonehara, Katsuya

    2012-01-01T23:59:59.000Z

    In order to develop an RF cavity that is applicable for a muon beam cooling channel, a new facility, called Mucool Test Area (MTA) has been built at Fermilab. MTA is a unique facility whose purpose is to test RF cavities in various conditions. There are 201 and 805 MHz high power sources, a 4-Tesla solenoid magnet, a cryogenic system including a Helium liquifier, an explosion proof apparatus to operate gaseous/liquid Hydrogen, and a beam transport line to send an intense H- beam from the Fermilab Linac accelerator to the MTA hall. Recent activities at MTA will be discussed in this document.

  19. The MuCool Test Area and RF Program

    SciTech Connect (OSTI)

    Torun, Y.; Huang, D.; /IIT, Chicago; Norem, J.; /Argonne; Palmer, Robert B.; Stratakis, Diktys; /Brookhaven; Bross, A.; Chung, M.; Jansson, A.; Moretti, A.; Yonehara, K.; /Fermilab; Li, D.; /LBL, Berkeley /Jefferson Lab

    2010-05-01T23:59:59.000Z

    The MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. Here we give an overview of the program, which includes a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field, which allows for a detailed study of the maximum stable operating gradient vs. magnetic field strength and angle.

  20. The MuCool Test Area and RF Program

    SciTech Connect (OSTI)

    Bross, A D; Jansson, A; Moretti, A; Yonehara, K; Huang, D; Torun, Y; Li, D; Norem, J; Palmer, R B; Stratakis, D

    2010-05-01T23:59:59.000Z

    The MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. This paper will give an overview of the program, which will include a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field which allows for a more detailed study of the maximum stable operating gradient vs. magnetic field strength and angle.

  1. The Los Alamos VXI-based modular RF control system

    SciTech Connect (OSTI)

    Jachim, S.P.; Ziomek, C.; Natter, E.F.; Regan, A.H.; Hill, J.; Eaton, L.; Gutscher, W.D.; Curtin, M.; Denney, P.; Hansberry, E.; Brooks, T.

    1993-01-01T23:59:59.000Z

    This paper describes the design and implementation of the Los Alamos modular RF control system, which provides high-performance feedback and/or feedforward control of RF accelerator cavities. This is a flexible, modular control system which has been realized in the industry-standard VXI cardmodular format. A wide spectrum of system functionality can be accommodated simply by incorporating only those modules and features required for a particular application. The fundamental principles of the design approach are discussed. Details of the VXI implementation are given, including the system architecture and interfaces, performance capabilities, and available features.

  2. The Los Alamos VXI-based modular RF control system

    SciTech Connect (OSTI)

    Jachim, S.P.; Ziomek, C.; Natter, E.F.; Regan, A.H.; Hill, J.; Eaton, L.; Gutscher, W.D.; Curtin, M.; Denney, P.; Hansberry, E.; Brooks, T.

    1993-06-01T23:59:59.000Z

    This paper describes the design and implementation of the Los Alamos modular RF control system, which provides high-performance feedback and/or feedforward control of RF accelerator cavities. This is a flexible, modular control system which has been realized in the industry-standard VXI cardmodular format. A wide spectrum of system functionality can be accommodated simply by incorporating only those modules and features required for a particular application. The fundamental principles of the design approach are discussed. Details of the VXI implementation are given, including the system architecture and interfaces, performance capabilities, and available features.

  3. High resolution gas phase infrared spectroscopy of the hydrogen bonded complex HCN---HF and its deuterated isotopic species 

    E-Print Network [OSTI]

    Jackson, Marc William

    1987-01-01T23:59:59.000Z

    Scan Over a Portion of the u6 Band 1 System of HCiV---HF 59 The Central Portion of the u6 Band of HCN- ? -HF 1 Showing the 3 Assignment of the Q-branch and a Portion of the P-branch 1 A Portion of the R-branch of the u6 Band of HCN---HF 60 10 A... region. Reported herein is the analysis of the rovibrational substructure of the ul(D-F), u2(C-D) and w3 (C=N) predissociating stretching vibrations of DCiV---DF. Numerous molecular constants were determined for these fundamentals along with a total...

  4. Comparison of electromagnetic, thermal and mechanical calculations with rf test results in rf-dipole deflecting/crabbing cavities

    SciTech Connect (OSTI)

    Park, HyeKyoung [JLAB, ODU; De Silva, Subashini U. [ODU; Delayen, Jean R. [ODU, JLAB

    2013-12-01T23:59:59.000Z

    The current requirements of higher gradients and strict dimensional constraints in the emerging applications have required the designing of compact deflecting and crabbing rf structures. The superconducting rf-dipole cavity is one of the first novel compact designs with attractive properties such as higher gradients, higher shunt impedance and widely separated higher order modes. The recent tests performed on proof-of-principle designs of the rf-dipole geometry at 4.2 K and 2.0 K in the vertical test area at Jefferson Lab have proven the designs to achieve higher gradients with higher intrinsic quality factors and easily processed multipacting conditions. The cavity characteristics, such as pressure sensitivity and Lorentz force detuning, were studied using ANSYS before the fabrication. These characteristics were measured during the cavity test. The comparison between the simulation and the measurement provides insight how the simulation can be used for design and fabrication of future cavities.

  5. Model for Simulation of Hydride Precipitation in Zr-Based Used...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    model that accounts for (microstucture) grain texture and orientation, and includes free energy of two Zr phases. The chemical potential that drives the compositional and phase...

  6. Crystallization and glass formation in electron and laser beam irradiated Cu-Zr alloys

    SciTech Connect (OSTI)

    Huang, J.S.; Kaufmann, E.N.; Wall, M.A.; Olsen, B.L.

    1987-11-01T23:59:59.000Z

    Four Cu-Zr alloys, Cu/sub 56/Zr/sub 44/, Cu/sub 50/Zr/sub 50/, Cu/sub 47/Zr/sub 53/, and Cu/sub 33/Zr/sub 67/, were surface melted with electron and pulsed laser beams to compare their kinetics of nucleation, growth and glass formation. It was observed that the ease of glass formation increased in the order: Cu/sub 33/Zr/sub 67/, Cu/sub 47/Zr/sub 53/, Cu/sub 56/Zr/sub 44/, and Cu/sub 50/Zr/sub 50/. The nucleation and regrowth produced different metastable phases. At the equiatomic composition, the preferred phase is a CsCl-type (B2) BCC structure. As the composition deviates from this, the preferred phase is either orthorhombic or tetragonal with a much larger unit cell not previously reported in the literature. The maximum growth velocity of these metastable phases was found to be about 0.025 m/s. The slow kinetics are responsible for the ease of glass formation in these systems. 4 refs., 7 figs., 2 tabs.

  7. Dynamics of Longitudinal Phase-Space Modulations in an rf Compressor for Electron Beams

    E-Print Network [OSTI]

    Venturini, M.

    2010-01-01T23:59:59.000Z

    gain along the rf compressor for perturbation wavelengths (drift followed by a 3 m rf compressor. The beam injected atat the exit of the compressor over a range of perturbation

  8. Advances in Filter Miniaturization and Design/Analysis of RF MEMS Tunable Filters

    E-Print Network [OSTI]

    Sekar, Vikram

    2012-10-19T23:59:59.000Z

    The main purpose of this dissertation was to address key issues in the design and analysis of RF/microwave filters for wireless applications. Since RF/microwave filters are one of the bulkiest parts of communication systems, their miniaturization...

  9. Identification of phases in the interaction layer between U-Mo-Zr/Al and U-Mo-Zr/Al-Si

    SciTech Connect (OSTI)

    Varela, C.L. Komar; Arico, S.F.; Mirandou, M.; Balart, S.N. [Departamento Materiales, GIDAT, GAEN, CNEA, Avda. Gral Paz 1499, B1650KNA, San Martin (Argentina); Gribaudo, L.M. [Departamento Materiales, GIDAT, GAEN, CNEA, Avda. Gral Paz 1499, B1650KNA, San Martin (Argentina); CONICET, Avda. Rivadavia 1917, C1033AAJ, Buenos Aires (Argentina)

    2008-07-15T23:59:59.000Z

    Out-of-pile diffusion experiments were performed between U-7wt.% Mo-1wt.% Zr and Al or Al A356 (7,1wt.% Si) at 550 deg. C. In this work morphological characterization and phase identification on both interaction layer are presented. They were carried out by the use of different techniques: optical and scanning electron microscopy, X-Ray diffraction and WDS microanalysis. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al, the phases UAl{sub 3}, UAl{sub 4}, Al{sub 20}Mo{sub 2}U and Al{sub 43}Mo{sub 4}U{sub 6} were identified. In the interaction layer U-7wt.% Mo-1wt.% Zr/Al A356, the phases U(Al, Si) with 25at.% Si and Si{sub 5}U{sub 3} were identified. This last phase, with a higher Si concentration, was identified with XRD Synchrotron radiation performed at the National Synchrotron Light Laboratory (LNLS), Campinas, Brasil. (author)

  10. MEDIUM POWER 352 MHZ SOLID STATE PULSED RF AMPLIFIERS FOR THE CERN LINAC4 PROJECT

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MEDIUM POWER 352 MHZ SOLID STATE PULSED RF AMPLIFIERS FOR THE CERN LINAC4 PROJECT J. Broere, J in the CERN Linac4. The amplifiers are water-cooled and can provide up to 33 kW pulsed RF Power, 1.5 ms pulse RF Power for the debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6

  11. The effects of layering in ferroelectric Si-doped HfO{sub 2} thin films

    SciTech Connect (OSTI)

    Lomenzo, Patrick D.; Nishida, Toshikazu, E-mail: nishida@ufl.edu [Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611 (United States); Takmeel, Qanit; Moghaddam, Saeed [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zhou, Chuanzhen; Liu, Yang; Fancher, Chris M.; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27696-7907 (United States)

    2014-08-18T23:59:59.000Z

    Atomic layer deposited Si-doped HfO{sub 2} thin films approximately 10?nm thick are deposited with various Si-dopant concentrations and distributions. The ferroelectric behavior of the HfO{sub 2} thin films are shown to be dependent on both the Si mol. % and the distribution of Si-dopants. Metal-ferroelectric-insulator-semiconductor capacitors are shown to exhibit a tunable remanent polarization through the adjustment of the Si-dopant distribution at a constant Si concentration. Inhomogeneous layering of Si-dopants within the thin films effectively lowers the remanent polarization. A pinched hysteresis loop is observed for higher Si-dopant concentrations and found to be dependent on the Si layering distribution.

  12. RF power potential of 45 nm CMOS technology

    E-Print Network [OSTI]

    Putnam, Christopher

    This paper presents the first measurements of the RF power performance of 45 nm CMOS devices with varying device widths and layouts. We find that 45 nm CMOS can deliver a peak output power density of around 140 mW/mm with ...

  13. RF gas plasma source development for heavy ion fusion

    SciTech Connect (OSTI)

    Ahle, L.E.; Hall, R.P.; Molvik, A.W.

    2002-02-22T23:59:59.000Z

    Presently the Heavy Ion Fusion Virtual National Laboratory is researching ion sources and injector concepts to understand how to optimize beam brightness over a range of currents (50-2000 mA argon equivalent). One concept initially accelerates millimeter size, milliamp beamlets to 1 MeV before merging them into centimeter size, ampere beams. Computer simulations have shown the final brightness of the merged beams is dominated by the emittance growth of the merging process, as long as the beamlets ion temperature is below a few eV. Thus, a RF multicusp source capable of high current density can produce beams with better brightness compared to ones extracted from a colder source with a large aperture and lower current density. As such, experiments have begun to develop a RF multicusp source capable of delivering one amp of extracted beam current. It is expected that it will require 10 kW of 13 MHz RF power delivered via a quartz shielded, one and half turn, four inch diameter antenna. Important considerations in the development of the source include the dependence of current density and beam ion temperature on consumed RF power and gas pressure. A fast rise time ({approx}100 ns) for the extracted beam pulse must also be achieved. Progress on these experiments will be presented.

  14. RF Gas Plasma Source Development for Heavy Ion Fusion

    SciTech Connect (OSTI)

    Ahle, L; Hall, R P; Molvik, A W; Kwan, J W; Leung, K N

    2001-09-04T23:59:59.000Z

    Presently the Heavy Ion Fusion Virtual National Laboratory is researching ion sources and injector concepts to understand how to optimize beam brightness over a range of currents (50-2000 mA argon equivalent). One concept initially accelerates millimeter size, milliamp beamlets to 1 MeV before merging them into centimeter size, ampere beams. Computer simulations have shown the final brightness of the merged beams is dominated by the emittance growth of the merging process, as long as the beamlets ion temperature is below a few eV. Thus, a RF multicusp source capable of high current density can produce beams with better brightness compared to ones extracted from a colder source with a large aperture and lower current density. As such, experiments have begun to develop a RF multicusp source capable of delivering one amp of extracted beam current. It is expected that it will require 10 kW of 13 MHz RF power delivered via a quartz shielded, one and half turn, four inch diameter antenna. Important considerations in the development of the source include the dependence of current density and beam ion temperature on consumed RF power and gas pressure. A fast rise time ({approx} 100 ns) for the extracted beam pulse must also be achieved. Progress on these experiments will be presented.

  15. PUBLISHED VERSION RF contact development for the ITER ICRH antenna

    E-Print Network [OSTI]

    Cyclotron (IC) antenna design, ITER Organization requested qualification tests on sliding Radio contacts in relevant conditions (2.25kA @ 62.5MHz, vacuum pressure detailed with RF power tests for long shot duration (1000s) under vacuum and extensive sliding tests

  16. Superfluid helium cryogenic systems for superconducting RF cavities at KEK

    SciTech Connect (OSTI)

    Nakai, H.; Hara, K.; Honma, T.; Hosoyama, K.; Kojima, Y.; Nakanishi, K. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0033 (Japan); Kanekiyo, T. [Hitachi Plant Technologies, Ltd., Toshima-ku, Tokyo 170-8466 (Japan); Morita, S. [Hitachi Plant Mechanics Co., Ltd., Kudamatsu, Yamaguchi 744-0061 (Japan)

    2014-01-29T23:59:59.000Z

    Recent accelerator projects at KEK, such as the Superconducting RF Test Facility (STF) for R and D of the International Linear Collider (ILC) project and the compact Energy Recovery Linac (cERL), employ superconducting RF cavities made of pure niobium, which can generate high gradient acceleration field. Since the operation temperature of these cavities is selected to be 2 K, we have developed two 2 K superfluid helium cryogenic systems for stable operation of superconducting RF cavities for each of STF and cERL. These two 2 K superfluid helium cryogenic systems are identical in principle. Since the operation mode of the cavities is different for STF and cERL, i.e. the pulse mode for STF and the continuous wave mode for cERL, the heat loads from the cavities are quite different. The 2 K superfluid helium cryogenic systems mainly consists of ordinary helium liquefiers/refrigerators, 2 K refrigerator cold boxes, helium gas pumping systems and high-performance transfer lines. The 2 K refrigerators and the high-performance transfer lines are designed by KEK. Some superconducting RF cavity cryomodules have been already connected to the 2 K superfluid helium cryogenic systems for STF and cERL respectively, and cooled down to 2 K successfully.

  17. Muon spin rotation studies of niobium for superconducting RF applications

    E-Print Network [OSTI]

    Grassellino, A; Kolb, P; Laxdal, R; Lockyer, N S; Longuevergne, D; Sonier, J E

    2013-01-01T23:59:59.000Z

    In this work we investigate superconducting properties of niobium samples via application of the muon spin rotation/relaxation (muSR) technique. We employ for the first time the muSR technique to study samples that are cutout from large and small grain 1.5 GHz radio frequency (RF) single cell niobium cavities. The RF test of these cavities was accompanied by full temperature mapping to characterize the RF losses in each of the samples. Results of the muSR measurements show that standard cavity surface treatments like mild baking and buffered chemical polishing (BCP) performed on the studied samples affect their surface pinning strength. We find an interesting correlation between high field RF losses and field dependence of the sample magnetic volume fraction measured via muSR. The muSR line width observed in ZF-muSR measurements matches the behavior of Nb samples doped with minute amounts of Ta or N impurities. An upper bound for the upper critical field Hc2 of these cutouts is found.

  18. Surface Superconductivity in Niobium for Superconducting RF Cavities0

    E-Print Network [OSTI]

    Surface Superconductivity in Niobium for Superconducting RF Cavities0 S. Casalbuoni1,2 , E) parameters of the ultrapure niobium used for the fabrication of the nine-cell 1.3 GHz cavities for the lin.3 GHz nine-cell cavities which are made from pure niobium and cooled by superfluid helium at 2 K. The 0

  19. Photonic RF oscillator based on monolithic DFB lasers with

    E-Print Network [OSTI]

    Boyer, Edmond

    Photonic RF oscillator based on monolithic DFB lasers with frequency-shifted feedback L. Wang, M by using monolithic dual-wavelength DFB semiconductor lasers submitted to a frequency-shifted optical. Dashed line: Lorentzian fit. (a) Free running, RBW: 30 kHz, span: 50 MHz. (b) With feedback, RBW: 1Hz

  20. rf testbed for thermoacoustic tomography D. Fallon,1

    E-Print Network [OSTI]

    Hanson, George

    rf testbed for thermoacoustic tomography D. Fallon,1 L. Yan,2 G. W. Hanson,3 and S. K. Patch4,a 1 Received 28 October 2008; accepted 22 April 2009; published online 9 June 2009 Thermoacoustic signal is a preferred acoustic coupling medium for thermoacoustics because acoustic and electromagnetic waves propagate

  1. Novel Reactor Relevant RF Actuator Schemes for the Lower

    E-Print Network [OSTI]

    location for RF launchers · Transport in tokamak sends heat and particles to low field side SOL: ­ Forces reactor is challenging: ­ Survivability is a major issue because of the harsh environment high heat solution that both mitigates PMI / coupling problems and improves core wave physics issues. #12;Reactor

  2. Dual Stewart Platform Mobility Simulator R.F. Boian1

    E-Print Network [OSTI]

    New Jersey, University of Medicine and Dentistry of

    Dual Stewart Platform Mobility Simulator R.F. Boian1 , M. Bouzit1 , G.C. Burdea1,* , and J. The system uses two Stewart platform robots to render the walking surface geometry and condition. The hardware components of the platforms and the considerations behind their design are presented here

  3. Suppressed Superconductivity on the Surface of Superconducting RF Quality Niobium for

    E-Print Network [OSTI]

    Suppressed Superconductivity on the Surface of Superconducting RF Quality Niobium for Particle 32310, USA Abstract. Significant performance degradation of superconducting RF (radio frequency) niobium superconductivity at chemically treated RF-quality niobium. We found that pinning of vortices along GBs is weaker

  4. Identification of Residual Stress State in an RF-MEMS Device

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    of wafer level tests. The membrane is part of an RF MEMS Switch man- ufactured by Raytheon Systems Co) and 3D numerical simulations. THE RAYTHEON'S RF MEMS SWITCH The RF MEMS switch technology developed by Raytheon Systems Co. provides advantageous characteristics for communication circuits by virtue of its

  5. Mode specificity in the HF + OH ? F + H{sub 2}O reaction

    SciTech Connect (OSTI)

    Song, Hongwei; Li, Jun; Guo, Hua, E-mail: hguo@unm.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-10-28T23:59:59.000Z

    Full-dimensional quantum dynamics and quasi-classical trajectory calculations are reported for the title reaction on a recently constructed ab initio based global potential energy surface. Strong mode specificity was found, consistent with the prediction of the sudden vector projection model. Specifically, the HF vibration strongly promotes the reaction while the OH vibration has little effect. Rotational excitations of both reactants slightly enhance the reaction.

  6. Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf)

    E-Print Network [OSTI]

    Simon, Anish Abraham

    2006-04-12T23:59:59.000Z

    NiTiHf alloys have attracted considerable attention as potential high temperature Shape Memory Alloy (SMA) but the instability in transformation temperatures and significant irrecoverable strain during thermal cycling under constant stress remains a...

  7. On the altitude of the ELF/VLF source region generated during "beat-wave" HF heating experiments

    E-Print Network [OSTI]

    by ionospheric heating, recent experiments at the High- frequency Active Auroral Research Program (HAARP experiments at the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska

  8. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) Application in the Evaluation of Management Risks

    E-Print Network [OSTI]

    Soguilon, Nenita M.

    2009-12-18T23:59:59.000Z

    .3.1. Mechanisms of Prevention ............................................................................................... 11 2.4. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) ....................... 11 2.5. FMEA Components... ........................................................................................... 15 2.5.5. Risk Priority Number ....................................................................................................... 17 2.6. FMEA Model...

  9. Upper atmospheric effects of the hf active auroral research program ionospheric research instrument (HAARP IRI)

    SciTech Connect (OSTI)

    Eccles, V.; Armstrong, R.

    1993-05-01T23:59:59.000Z

    The earth's ozone layer occurs in the stratosphere, primarily between 10 and 30 miles altitude. The amount of ozone, O3, present is the result of a balance between production and destruction processes. Experiments have shown that natural processes such as auroras create molecules that destroy O. One family of such molecules is called odd nitrogen of which nitric oxide (NO) is an example. Because the HAARP (HF Active Auroral Research Program) facility is designed to mimic and investigate certain natural processes, a study of possible effects of HAARP on the ozone layer was conducted. The study used a detailed model of the thermal and chemical effects of the high power HF beam, which interacts with free electrons in the upper atmosphere above 50 miles altitude. It was found only a small fraction of the beam energy goes into the production of odd nitrogen molecules, whereas odd nitrogen is efficiently produced by auroras. Since the total energy emitted by HAARP in the year is some 200,000 times less than the energy deposited in the upper atmosphere by auroras, the study demonstrates that HAARP HF beam experiments will cause no measurable depletion of the earth's ozone layer.... Ozone, Ozone depletion, Ozone layer, Odd nitrogen, Nitric oxide, HAARP Emitter characteristics.

  10. Continued development of modeling tools and theory for RF heating

    SciTech Connect (OSTI)

    NONE

    1998-12-01T23:59:59.000Z

    Mission Research Corporation (MRC) is pleased to present the Department of Energy (DOE) with its renewal proposal to the Continued Development of Modeling Tools and Theory for RF Heating program. The objective of the program is to continue and extend the earlier work done by the proposed principal investigator in the field of modeling (Radio Frequency) RF heating experiments in the large tokamak fusion experiments, particularly the Tokamak Fusion Test Reactor (TFTR) device located at Princeton Plasma Physics Laboratory (PPPL). An integral part of this work is the investigation and, in some cases, resolution of theoretical issues which pertain to accurate modeling. MRC is nearing the successful completion of the specified tasks of the Continued Development of Modeling Tools and Theory for RF Heating project. The following tasks are either completed or nearing completion. (1) Anisotropic temperature and rotation upgrades; (2) Modeling for relativistic ECRH; (3) Further documentation of SHOOT and SPRUCE. As a result of the progress achieved under this project, MRC has been urged to continue this effort. Specifically, during the performance of this project two topics were identified by PPPL personnel as new applications of the existing RF modeling tools. These two topics concern (a) future fast-wave current drive experiments on the large tokamaks including TFTR and (c) the interpretation of existing and future RF probe data from TFTR. To address each of these topics requires some modification or enhancement of the existing modeling tools, and the first topic requires resolution of certain theoretical issues to produce self-consistent results. This work falls within the scope of the original project and is more suited to the project`s renewal than to the initiation of a new project.

  11. The RF power system for the SNS linac

    SciTech Connect (OSTI)

    Tallerico, P.J.; Reass, W.A.

    1998-12-31T23:59:59.000Z

    The initial goal of the SNS project is to produce a 1 MW average beam of protons with short pulse lengths onto a neutron-producing target. The objective of the SNS RF system is to generate 117 MW peak of pulsed 805 MHz microwave power with an accelerated beam pulse length of 1.04 ms at a 60 Hz repetition rate. The power system must be upgradeable in peak power to deliver 2 MW average power to the neutron target. The RF system also requires about 3 MW peak of RF power at 402.5 MHz, but that system is not discussed here. The design challenge is to produce an RF system at minimum cost, that is very reliable and economical to operate. The combination of long pulses and high repetition rates make conventional solutions, such as the pulse transformer and transmission line method, very expensive. The klystron, with a modulating anode, and 1.5 MW of peak output power is the baseline RF amplifier, an 56 are required in the baseline design. The authors discuss four power system configurations that are the candidates for the design. The baseline design is a floating-deck modulating anode system. A second power system being investigated is the fast-pulsed power supply, that can be turned on and off with a rise time of under 0.1 ms. This could eliminate the need for a modulator, and drastically reduce the energy storage requirements. A third idea is to use a pulse transformer with a series IGBT switch and a bouncer circuit on the primary side, as was done for the TESLA modulator. A fourth method is to use a series IGBT switch at high voltage, and not use a pulse transformer. The authors discuss the advantages and problems of these four types of power systems, but they emphasize the first two.

  12. Comparative Analysis of Carbon Plasma in Arc and RF Reactors

    SciTech Connect (OSTI)

    Todorovic-Markovic, B.; Markovic, Z. ['Vinca' Institute of Nuclear Sciences, P.O.B. 522, 11001 Belgrade (Serbia and Montenegro); Mohai, I.; Szepvolgyi, J. [Research Laboratory of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences H-1525 Budapest, POB 17 (Hungary)

    2004-12-01T23:59:59.000Z

    Results on studies of molecular spectra emitted in the initial stages of fullerene formation during the processing of graphite powder in induction RF reactor and evaporation of graphite electrodes in arc reactor are presented in this paper. It was found that C2 radicals were dominant molecular species in both plasmas. C2 radicals have an important role in the process of fullerene synthesis. The rotational-vibrational temperatures of C2 and CN species were calculated by fitting the experimental spectra to the simulated ones. The results of optical emission study of C2 radicals generated in carbon arc plasma have shown that rotational temperature of C2 species depends on carbon concentration and current intensity significantly. The optical emission study of induction RF plasma and SEM analysis of graphite powder before and after plasma treatment have shown that evaporation of the processed graphite powder depends on feed rate and composition of gas phase significantly. Based on the obtained results, it was concluded that in the plasma region CN radicals could be formed by the reaction of C2 species with atomic nitrogen at smaller loads. At larger feed rate of graphite powder, CN species were produced by surface reaction of the hot carbon particles with nitrogen atoms. The presence of nitrogen in induction RF plasma reduces the fullerene yield significantly. The fullerene yield obtained in two different reactors was: 13% in arc reactor and 4.1% in induction RF reactor. However, the fullerene production rate was higher in induction RF reactor-6.4 g/h versus 1.7 g/h in arc reactor.

  13. High temperature ablation resistance of ZrNp reinforced W matrix composites

    E-Print Network [OSTI]

    Hong, Soon Hyung

    High temperature ablation resistance of ZrNp reinforced W matrix composites Malik Adeel Umer October 2013 Keywords: Metal-matrix composites (MMCs) Powder metallurgy Oxidation Scanning electron-based materials, a new class of composites was fabricated using particulate ZrN as reinforcement. The high

  14. Densification and microstructure development in spark plasma sintered WC6 wt% ZrO2 nanocomposites

    E-Print Network [OSTI]

    Srivastava, Kumar Vaibhav

    Densification and microstructure development in spark plasma sintered WC­6 wt% ZrO2 nanocomposites nanocomposite, spark plasma sintered at 1300 °C, for varying times of up to 20 min. The primary aim of this work investigation indicated that ZrO2 in the spark plasma sintered nanocomposite adopted an orthorhombic crystal

  15. Thermoelectric Transport in a ZrN/ScN Superlattice MONA ZEBARJADI,1

    E-Print Network [OSTI]

    Thermoelectric Transport in a ZrN/ScN Superlattice MONA ZEBARJADI,1 ZHIXI BIAN,1 RAJEEV SINGH,1 ALI for a high thermoelectric figure of merit. The thermopower of these structures can be enhanced by controlling and experimental studies of the thermoelectric transport in ZrN/ScN metal/semiconductor superlattices. Preliminary

  16. Atomistic Studies of Cation Transport in Tetragonal ZrO2 During Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2013-10-01T23:59:59.000Z

    Zirconium alloys are the major fuel cladding materials in current reactors. The water-side corrosion is one of the major degradation mechanisms of these alloys. During corrosion the transport of oxidizing species in zirconium dioxide (ZrO2) determines the corrosion kinetics. Previously it has been argued that the outward diffusion of cation ions is important for forming protective oxides. In this work, the migration of Zr defects in tetragonal ZrO2 is studied with temperature accelerated dynamics and molecular dynamics simulations. The results show that Zr interstitials have anisotropic diffusion and migrate preferentially along the [001] or c direction in tetragonal ZrO2. The compressive stresses can increase the Zr interstitial migration barrier significantly. The migration barriers of some defect clusters can be much lower than those of point defects. The migration of Zr interstitials at some special grain boundaries is much slower than in a bulk oxide. The implications of these atomistic simulation results in the Zr corrosion are discussed.

  17. Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy

    E-Print Network [OSTI]

    Pennycook, Steve

    Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy C.T. Liu*, M composition Zr­10 at.%Al­5% Ti­17.9% Cu­14.6% Ni (BAM-11) was used to study the effects of oxygen impurities and microalloying on the microstructure and mechanical properties. Oxygen impurity at a level of 3000 appm

  18. Isoscalar Breathing Mode State in Zr-90 and Sn-116

    E-Print Network [OSTI]

    Rozsa, C. M.; Youngblood, David H.; Bronson, J. D.; Lui, YW; Garg, U.

    1980-01-01T23:59:59.000Z

    PHYSICAL RKVIK% C VOLUIHE 21, NUMBER 4 Isoscalar breathing mode state in Zr and "Sn C. M. Rozsa, D. H. Youngblood, J. D. Bronson, Y.-%. Lui, and U. Garg Cyclotron Institute, Texas AckM University, College Station, Texas 77843 (Received 5..., BRONSON, LUI, AND GARG larger opening and served to catch some particles scattered from the first set. For measurements at 0', the beam was passed into the spectrograph and one set of brass defining slits with an open- ing of 6.4' horizontally by 3.V...

  19. Report on Characterization of U-10 wt.% Zr Alloy

    SciTech Connect (OSTI)

    McKeown, J; Wall, M; Hsiung, L; Turchi, P

    2012-03-01T23:59:59.000Z

    This report summarizes the chemical and structural characterization results for a U-10 wt.% Zr alloy to be used in an ultra-high burn-up nuclear fuel concept. The as-cast alloy material was received from Texas A and M University. Characterization and an initial heat treatment of the alloy material were conducted at Lawrence Livermore National Laboratory. The as-received ingot was sectioned for X-ray analysis, metallography, SEM, TEM, and heat treatments, as shown in Figure 1.

  20. Shape co-existence and parity doublet in Zr isotopes

    E-Print Network [OSTI]

    Bharat Kumar

    2014-12-05T23:59:59.000Z

    We studied the ground and excited states properties for Zr isotopes starting^M from proton to neutron drip-lines using the relativistic and non-relativistic mean field formalisms with BCS and Bogolyubov pairing. The celebrity NL3 and SLy4 parameter sets are used in the calculations. We find spherical ground and low-lying^M superdeformed excited states in most of the isotopes. Several couples of^M $\\Omega^{\\pi}=1/2^{\\pm}$ parity doublets configurations are found,^M while analyzing the single-particle energy levels of the superdeformed ^M configurations.

  1. Magnetic properties of Co-Zr-B magnets produced by spark plasma sintering method

    SciTech Connect (OSTI)

    Saito, Tetsuji, E-mail: tetsuji.saito@it-chiba.ac.jp; Akiyama, Tomoya [Department of Mechanical Science and Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan)

    2014-05-07T23:59:59.000Z

    Magnets of Co-Zr-B, one of the permanent magnetic compounds without rare-earth elements, were successfully produced by the spark plasma sintering method. The resultant Co-Zr-B magnets had high densities of 92%–96% and consisted mainly of the Co{sub x}Zr (x ? 5) phase. The coercivity of the Co-Zr-B magnets was highly dependent on the consolidation temperature and the boron content. The highest maximum energy product of 6.0 MGOe, with a remanence of 6.4 kG and the coercivity of 4.0 kOe, was achieved by the Co{sub 80}Zr{sub 18}B{sub 2} magnets consolidated at 873?K.

  2. Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

    E-Print Network [OSTI]

    Zhao, Xin; Nguyen, Manh Cuong; Wang, Cai-Zhuang; Ho, Kai-Ming

    2015-01-01T23:59:59.000Z

    The structures and magnetic properties of the Co-Zr-B alloys near the Co5Zr composition were studied using adaptive genetic algorithm and first-principles calculations to guide further experimental effort on optimizing their magnetic performances. Through extensive structural searches, we constructed the contour maps of the energetics and magnetic moments of the Co-Zr-B magnet alloys as a function of composition. We found that the Co-Zr-B system exhibits the same structural motif as the "Co11Zr2" polymorphs, which plays a key role in achieving high coercivity. Boron atoms can either substitute selective cobalt atoms or occupy the interstitial sites. First-principles calculation shows that the magnetocrystalline anisotropy energies can be significantly improved through proper boron doping.

  3. Induction heating of FeCo nanoparticles for rapid rf curing of epoxy K. J. Miller,1,a

    E-Print Network [OSTI]

    McHenry, Michael E.

    , and cracking of the polymer. An alternative curing process involves remote, noncontact rf heating of MNP loadedInduction heating of FeCo nanoparticles for rapid rf curing of epoxy composites K. J. Miller,1,a K epoxy composites through radio-frequency rf heating. The rf response of functionalized FeCo MNPs

  4. RF Power Degradation of GaN High Electron Mobility Transistors Jungwoo Joh and Jess A. del Alamo

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    RF Power Degradation of GaN High Electron Mobility Transistors Jungwoo Joh and Jesús A. del Alamo Transistors. Our technique utilizes RF and DC figures of merit to diagnose the degradation of RF stressed and to introduce new degradation modes. At high power level, RF stress induces a prominent trapping

  5. RF telemetry makes complex surveys quick, cost-effective

    SciTech Connect (OSTI)

    Rigdon, H.K. [Nemaha Resources, Inc., Tulsa, OK (United States)

    1996-05-01T23:59:59.000Z

    Field seismic crews can gather full-range or wide-azimuth seismic datasets for 3-D surveys at costs competitive with 2-D seismic acquisition through the use of Radio Frequency (RF) telemetry acquisition systems. By eliminating need for data cables, RF telemetry systems, such as the Opseis Eagle System, can record 3-D data volumes using proven 2-D recording geometries that are a natural extension of one-dimensional (split spread) design. Design advantages include: (1) uniform sampling in both X (in-line) and Y (lateral) directions; (2) excellent offset and azimuthal distribution common to each 3-D stacking bin, and (3) uniform fold across the survey area necessary for amplitude analysis.

  6. RF modulation studies on the S band pulse compressor

    E-Print Network [OSTI]

    Shu, G; Pei, S; Xiao, O

    2015-01-01T23:59:59.000Z

    An S band SLED-type pulse compressor has been manufactured by IHEP to challenge the 100 MW maximum input power, which means the output peak power is about 500 MW at the phase reversal time. In order to deal with the RF breakdown problem, the dual side-wall coupling irises model was used. To further improve the reliability at very high power, amplitude modulation and phase modulation with flat-top output were taken into account. The RF modulation studies on an S-band SLED are presented in this paper. Furthermore, a method is developed by using the CST Microwave Studio transient solver to simulate the time response of the pulse compressor, which can be a verification of the modulate theory. In addition, the experimental setup was constructed and the flat-top output is obtained in the low power tests.

  7. RF modulation studies on the S band pulse compressor

    E-Print Network [OSTI]

    G. Shu; F. Zhao; S. Pei; O. Xiao

    2015-05-28T23:59:59.000Z

    An S band SLED-type pulse compressor has been manufactured by IHEP to challenge the 100 MW maximum input power, which means the output peak power is about 500 MW at the phase reversal time. In order to deal with the RF breakdown problem, the dual side-wall coupling irises model was used. To further improve the reliability at very high power, amplitude modulation and phase modulation with flat-top output were taken into account. The RF modulation studies on an S-band SLED are presented in this paper. Furthermore, a method is developed by using the CST Microwave Studio transient solver to simulate the time response of the pulse compressor, which can be a verification of the modulate theory. In addition, the experimental setup was constructed and the flat-top output is obtained in the low power tests.

  8. Free electron laser using Rf coupled accelerating and decelerating structures

    DOE Patents [OSTI]

    Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

    1984-01-01T23:59:59.000Z

    A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

  9. Multipacting optimization of a 750 MHz rf dipole

    SciTech Connect (OSTI)

    Delayen, Jean R. [JLAB, Old Dominion University; Castillo, Alejandro [JLAB, Old Dominion University

    2014-12-01T23:59:59.000Z

    Crab crossing schemes have been proposed to re-instate luminosity degradation due to crossing angles at the interaction points in next generation colliders to avoid the use of sharp bending magnets and their resulting large synchrotron radiation generation, highly undessirable in the detector region. The rf dipole has been considered for a different set of applications in several machines, both rings and linear colliders. We present in this paper a study of the effects on the multipacting levels and location depending on geometrical variations on the design for a crabbing/deflecting application in a high current (3/0.5 A), high repetition (750 MHz) electron/proton collider, as a matter to provide a comparison point for similar applications of rf dipoles.

  10. Characterization on RF magnetron sputtered niobium pentoxide thin films

    SciTech Connect (OSTI)

    Usha, N. [Department of Physics, Alagappa University, Karaikudi - 630 004 (India); Sivakumar, R., E-mail: krsivakumar1979@yahoo.com [Directorate of Distance Education, Alagappa University, Karaikudi - 630 004 (India); Sanjeeviraja, C. [Department of Physics, Alagappa Chettiar College of Engineering and Technology, Karaikudi - 630 004 (India)

    2014-10-15T23:59:59.000Z

    Niobium pentoxide (Nb{sub 2}O{sub 5}) thin films with amorphous nature were deposited on microscopic glass substrates at 100°C by rf magnetron sputtering technique. The effect of rf power on the structural, morphological, optical, and vibrational properties of Nb{sub 2}O{sub 5} films have been investigated. Optical study shows the maximum average transmittance of about 87% and the optical energy band gap (indirect allowed) changes between 3.70 eV and 3.47 eV. AFM result indicates the smooth surface nature of the samples. Photoluminescence measurement showed the better optical quality of the deposited films. Raman spectra show the LO-TO splitting of Nb-O stretching of Nb{sub 2}O{sub 5} films.

  11. Induction barrier RF and applications in Main Injector

    SciTech Connect (OSTI)

    Chou, W.; Wildman, D.; /Fermilab; Takagi, A.; /KEK, Tsukuba

    2006-07-01T23:59:59.000Z

    Two induction barrier rf systems have been designed and fabricated at Fermilab and installed in the Main Injector. They use the nanocrystal magnetic alloy called Finemet for the cavities and high voltage fast MOSFET switches for the modulators. Each system delivers {+-}10 kV square pulses at 90 kHz. They have been used for adiabatic beam stacking (beam compression), machine acceptance measurement and gap cleaning in the injection area for magnet protection, and will be tested for fast beam stacking for doubling the proton flux on the NuMI production target. The systems work reliably and cost much less than a resistive barrier rf system. Comparison with a similar system built at KEK reveals many similarities and also some important differences. This work is partially funded by the US-Japan collaborative agreement.

  12. RF Input Power Couplers for High Current SRF Applications

    SciTech Connect (OSTI)

    Khan, V. F. [Helmholtz Zentrum Berlin, Germany; Anders, W. [Helmholtz Zentrum Berlin, Germany; Burrill, Andrew [Helmholtz Zentrum Berlin, Germany; Knobloch, Jens [Helmholtz Zentrum Berlin, Germany; Kugeler, Oliver [Helmholtz Zentrum Berlin, Germany; Neumann, Axel [Helmholtz Zentrum Berlin, Germany; Wang, Haipeng [JLAB

    2014-12-01T23:59:59.000Z

    High current SRF technology is being explored in present day accelerator science. The bERLinPro project is presently being built at HZB to address the challenges involved in high current SRF machines with the goal of generating and accelerating a 100 mA electron beam to 50 MeV in continuous wave (cw) mode at 1.3 GHz. One of the main challenges in this project is that of handling the high input RF power required for the photo-injector as well as booster cavities where there is no energy recovery process. A high power co-axial input power coupler is being developed to be used for the photo-injector and booster cavities at the nominal beam current. The coupler is based on the KEK–cERL design and has been modified to minimise the penetration of the coupler tip in the beam pipe without compromising on beam-power coupling (Qext ~105). Herein we report on the RF design of the high power (115 kW per coupler, dual couplers per cavity) bERLinPro (BP) coupler along with initial results on thermal calculations. We summarise the RF conditioning of the TTF-III couplers (modified for cw operation) performed in the past at BESSY/HZB. A similar conditioning is envisaged in the near future for the low current SRF photo-injector and the bERLinPro main linac cryomodule.

  13. Effect of electron-phonon interaction on resistivity of some heavy fermion (HF) systems

    SciTech Connect (OSTI)

    Sahoo, J., E-mail: jitendrasahoo2008@gmail.com [Assistant Director, Regional Office of Vocational Education, Sambalpur, Odisha-768004 (India); Shadangi, N. [Dept. of Physics, Silicon Institute of Technology, Sambalpur, Odisha-768200 (India); Nayak, P. [School of Physics, Sambalpur University, Sambalpur, Odisha-768019 (India)

    2014-04-24T23:59:59.000Z

    Here, we have analyzed the electron-phonon interaction in the Periodic Anderson Model (PAM) to describe the temperature dependence of resistivity in some heavy fermion (HF) systems for finite wave vector (q) and for finite temperature (T). Since the resistivity is related to the imaginary part of the electron self energy, the expression for the same is evaluated through double time temperature dependant Green function technique of the Zubarev type. The effect of different system parameters namely the position of 4f level, E{sub 0} and the electron - phonon coupling strengths on resistivity have been studied. The results obtained give satisfactory explanations to the experimental observations.

  14. Isothermal oxidation behavior of ternary Zr-Nb-Y alloys at high temperature

    SciTech Connect (OSTI)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia); Soepriyanto, Syoni; Basuki, Eddy Agus [Metallurgy Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Wiryolukito, Slameto [Materials Engineering, Institute Technology Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    The effect of yttrium content on isothermal oxidation behavior of Zr-2,5%Nb-0,5%Y, Zr-2,5%Nb-1%Y Zr-2,5%Nb-1,5%Y alloy at high temperature has been studied. High temperature oxidation carried out at tube furnace in air at 600,700 and 800°C for 1 hour. Optical microscope is used for microstructure characterization of the alloy. Oxidized and un oxidized specimen was characterized by x-ray diffraction. In this study, kinetic oxidation of Zr-2,5%Nb with different Y content at high temperature has also been studied. Characterization by optical microscope showed that microstructure of Zr-Nb-Y alloys relatively unchanged and showed equiaxed microstructure. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO2 while unoxidised alloy showed two phase ? and ? phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate.

  15. Ab initio density functional theory study of uranium solubility in Gd2Zr2O7 pyrochlore

    E-Print Network [OSTI]

    Chen, Qing-yun; Meng, Chuan-min; Liao, Chang-zhong; Wang, Lie-lin; Xie, Hua; Lv, Hui-yi; Wu, Tao; Ji, Shi-yin; Huang, Yu-zhu

    2015-01-01T23:59:59.000Z

    In this study, an ab initio calculation is performed to investigate the uranium solubility in different sites of Gd2Zr2O7 pyrochlore. The Gd2Zr2O7 maintains its pyrochlore structure at low uranium dopant levels, and the lattice constants of Gd2(Zr2-yUy)O7 and (Gd2-yUy)Zr2O7 are generally expressed as being linearly related to the uranium content y. Uranium is found to be a preferable substitute for the B-site gadolinium atoms in cation-disordered Gd2Zr2O7 (where gadolinium and zirconium atoms are swapped) over the A-site gadolinium atoms in ordered Gd2Zr2O7 due to the lower total energy of (Gd2-yZry)(Zr2-yUy)O7. The theoretical findings present a reasonable explanation of recent experiment results.

  16. Comparison of femtosecond and nanosecond laser-induced damage in HfO{sub 2} single-layer film and HfO{sub 2}-SiO{sub 2} high reflector

    SciTech Connect (OSTI)

    Yuan Lei; Zhao Yuanan; Shang Guangqiang; Wang Chengren; He Hongbo; Shao Jianda; Fan Zhengxiu [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2007-03-15T23:59:59.000Z

    HfO{sub 2} single layers, 800 nm high-reflective (HR) coating, and 1064 nm HR coating were prepared by electron-beam evaporation. The laser-induced damage thresholds (LIDTs) and damage morphologies of these samples were investigated with single-pulse femtosecond and nanosecond lasers. It is found that the LIDT of the HfO{sub 2} single layer is higher than the HfO{sub 2}-SiO{sub 2} HR coating in the femtosecond regime, while the situation is opposite in the nanosecond regime. Different damage mechanisms are applied to study this phenomenon. Damage morphologies of all samples due to different laser irradiations are displayed.

  17. Diffusional Interactions between U-Mo and Zr at 650°C as a Function of Time

    SciTech Connect (OSTI)

    Y. Park; Y. H. Sohn; D. D. Keiser, Jr.

    2015-01-01T23:59:59.000Z

    Development of monolithic U-Mo alloy fuel (typically U-10wt.%Mo) for the Reduced Enrichment for Research and Test Reactors (RERTR) program requires a use of Zr diffusion barrier to eliminate the diffusional interaction between the fuel alloy and Al-alloy cladding. The application of Zr barrier to the U-Mo fuel requires co-rolling process that utilizes a soaking temperature of 650°C, which represents the highest temperature the fuel system is exposed to during both fuel manufacturing and reactor application. Therefore, in this study, development of phase constituents, microstructure and diffusion kinetics of U-10wt.%Mo and Zr was examined using solid-to-solid diffusion couples annealed at 650°C for 240, 480 and 720 hours. Diffusional interactions were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Within the diffusion zone, a single-phase layer of ß-Zr was observed along with a discontinuous layer of Mo2Zr at the interface between the terminal ?-U(Mo) alloy and ß-Zr. In the vicinity of Mo2Zr phase, islands of ß-U and a-Zr phases were also found. In addition, accicular a-Zr phases were observed within the ?-U(Mo). Growth rate of this diffuaional interaction layer was determined to be 8.76 x 10-15 m2/sec, however with an assumption of certain incubation period. Consistency in these observation along with concentration profiles and diffusion paths are presented and discussed with respect to the diffusion couple that was furnace-cooled, annealed at 700°C in our previous study, and isothermal ternary phase diagram at 700°C.

  18. Twin peak HF QPOs as a spectral imprint of dual oscillation modes of accretion tori

    E-Print Network [OSTI]

    Bakala, Pavel; Török, Gabriel; Šrámková, Eva; Abramowicz, Marek A; Vincent, Frederic H; Mazur, Grzegorz P

    2015-01-01T23:59:59.000Z

    High frequency (millisecond) quasi-periodic oscillations (HF QPOs) are observed in the X-ray power-density spectra of several microquasars and low mass X-ray binaries. Two distinct QPO peaks, so-called twin peak QPOs, are often detected simultaneously exhibiting their frequency ratio close or equal to 3/2. Following the analytic theory and previous studies of observable spectral signatures, we aim to model the twin peak QPOs as a spectral imprint of specific dual oscillation regime defined by a combination of the lowest radial and vertical oscillation mode of optically thick slender tori with constant specific angular momentum. We examined power spectra and fluorescent K$\\alpha$ iron line profiles for two different simulation setups with the mode frequency relations corresponding to the epicyclic resonance HF QPOs model and modified relativistic precession QPOs model. We use relativistic ray-tracing implemented in parallel simulation code LSDplus. In the background of the Kerr spacetime geometry, we analyze t...

  19. First observation of /sup 162/Hf decay completion of an alpha -decay chain

    E-Print Network [OSTI]

    Schrewe, U J; Hagberg, E; Hardy, J C; Koslowsky, V T; Schmeing, H; Sharma, K S

    1981-01-01T23:59:59.000Z

    The new isotope /sup 162/Hf (T/sub 1/2/=(37.6+or-0.8)s) is produced in a /sup 142/Nd (/sup 24/Mg,4n) reaction. The activities produced in this reaction are transported to a measuring station by use of a He- jet system. Decay properties are observed with alpha -, gamma -, and gamma - gamma -spectroscopy. The Z-assignment of the new isotope is based on a cross bombardment on /sup 141/Pr target and on the results of a gamma -X-ray coincidence measurement. The mass assignment is deduced from the excitation function measurements. From the measured alpha -decay energy E/sub alpha /=4308 (10) keV new mass values are derived for /sup 162/Hf, /sup 166/W, /sup 170/Os, /sup 174/Pt, and /sup 178/Hg. These new mass values make it possible to establish systematics of two-proton and one-proton binding energies far from stability. (20 refs).

  20. Ultrananocrystalline diamond films with optimized dielectric properties for advanced RF MEMS capacitive switches

    DOE Patents [OSTI]

    Sumant, Anirudha V.; Auciello, Orlando H.; Mancini, Derrick C.

    2013-01-15T23:59:59.000Z

    An efficient deposition process is provided for fabricating reliable RF MEMS capacitive switches with multilayer ultrananocrystalline (UNCD) films for more rapid recovery, charging and discharging that is effective for more than a billion cycles of operation. Significantly, the deposition process is compatible for integration with CMOS electronics and thereby can provide monolithically integrated RF MEMS capacitive switches for use with CMOS electronic devices, such as for insertion into phase array antennas for radars and other RF communication systems.

  1. New SLED 3 system for Multi-mega Watt RF compressor

    E-Print Network [OSTI]

    Xu, Chen; Tantawi, Sami

    2014-01-01T23:59:59.000Z

    A compact X band SLED is introduced for X band RF compressing application. This SLED compressor consists two major parts: a rectangular to circular waveguide converter and an overmoded spherical cavity. The RF compressor is designed to convert 50 magawatt X band RF power with pulse length 1.5 microseconds and deliver 200 megawatts with pulse length 106 nanoseconds to the X band accelerating structure.

  2. Commissioning of a higher harmonic RF system for the Advanced Light Source

    E-Print Network [OSTI]

    Byrd, John M.; De Santis, Stefano; Georgsson, Mattias; Stover, G.; Fox, John D.; Teytelman, Dmitry

    2000-01-01T23:59:59.000Z

    Commissioning of a higher harmonic RF system for theAbstract We report on the commissioning of a higher harmonicpresents the results of commissioning of the ALS harmonic

  3. RF physics of ICWC discharge at high cyclotron harmonics

    SciTech Connect (OSTI)

    Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M. [Association Euratom-Belgian State, LPP-ERM-KMS, 1000 Brussels (Belgium); Bobkov, V.; Rohde, V.; Schneider, P. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Douai, D.; Kogut, D. [Association Euratom-CEA, CEA, IRFM, 13108 St Paul lez Durance (France); Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G. [Association Euratom-IEK-4, Forschungszentrum Jülich, 52425 Jülich (Germany); Moiseenko, V. [Institute of Plasma Physics NSC KIPT, 61108 Kharkiv (Ukraine); Noterdaeme, J.-M. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching, Germany and Ghent University, 9000 Ghent (Belgium); Collaboration: TEXTOR Team; ASDEX Upgrade Team

    2014-02-12T23:59:59.000Z

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,?=?{sub H+}, and with its high cyclotron harmonics (HCH), ?=10?{sub cH+}? HCH scenario: very high antenna coupling to low density RF plasmas (P{sub pl}?0.9P{sub RF-G}) and low energy Maxwellian distribution of CX hydrogen atoms with temperature T{sub H}?350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E{sub ?H} ?1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of B{sub T}-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low T{sub e} plasmas is studied at fundamental ICR and its high harmonics.

  4. MHD simulation of RF current drive in MST

    SciTech Connect (OSTI)

    Hendries, E. R.; Anderson, J. K.; Forest, C. B.; Reusch, J. A.; Seltzman, A. H.; Sovinec, C. R. [University of Wisconsin, Madison WI (United States); Diem, S. [Oak Ridge National Laboratory, Oak Ridge TN (United States); Harvey, R. W. [CompX, Del Mar, CA (United States)

    2014-02-12T23:59:59.000Z

    Auxiliary heating and current drive using RF waves such as the electron Bernstein wave (EBW) promises to advance the performance of the reversed field pinch (RFP). In previous computational work [1], a hypothetical edge-localized current drive is shown to suppress the tearing activity which governs the macroscopic transport properties of the RFP. The ideal conditions for tearing stabilization include a reduced toroidal induction, and precise width and radial position of the Gaussian-shaped external current drive. In support of the EBW experiment on the Madison Symmetric Torus, an integrated modeling scheme now incorporates ray tracing and Fokker-Plank predictions of auxiliary current into single fluid MHD. Simulations at low Lundquist number (S ? 10{sup 4}) generally agree with the previous work; significantly more burdensome simulations at MST-like Lundquist number (S ? 3×10{sup 6}) show unexpected results. The effect on nonlinearly saturated current profile by a particular RF-driven external force decreases in magnitude and widens considerably as the Lundquist number increases toward experimental values. Simulations reproduce the periodic current profile relaxation events observed in experiment (sawteeth) in the absence of current profile control. Reduction of the tearing mode amplitudes is still observable; however, reduction is limited to periods between the large bursts of magnetic activity at each sawtooth. The sawtoothing pattern persists with up to 10 MW of externally applied RF power. Periods with prolonged low tearing amplitude are predicted with a combination of external current drive and a reduced toroidal loop voltage, consistent with previous conclusions. Finally, the resistivity profile is observed to have a strong effect on the optimal externally driven current profile for mode stabilization.

  5. RF heating systems evolution for the WEST project

    SciTech Connect (OSTI)

    Magne, R.; Achard, J.; Armitano, A.; Argouarch, A.; Berger-By, G.; Bernard, J. M.; Bouquey, F.; Charabot, N.; Colas, L.; Corbel, E.; Delpech, L.; Ekedahl, A.; Goniche, M.; Guilhem, D.; Hillairet, J.; Jacquot, J.; Joffrin, E.; Litaudon, X.; Lombard, G.; Mollard, P. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); and others

    2014-02-12T23:59:59.000Z

    Tore Supra is dedicated to long pulse operation at high power, with a record in injected energy of 1 GJ (2.8 MW × 380 s) and an achieved capability of 12 MW injected power delivered by 3 RF systems: Lower Hybrid Current Drive (LHCD), Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH). The new WEST project (W [tungsten] Environment in Steady-state Tokamak) aims at fitting Tore Supra with an actively cooled tungsten coated wall and a bulk tungsten divertor. This new device will offer to ITER a test bed for validating the relevant technologies for actively cooled metallic components, with D-shaped H-mode plasmas. For WEST operation, different scenarii able to reproduce ITER relevant conditions in terms of steady state heat loads have been identified, ranging from a high RF power scenario (15 MW, 30 s) to a high fluence scenario (10 MW, 1000 s). This paper will focus on the evolution of the RF systems required for WEST. For the ICRH system, the main issues are its ELM resilience and its CW compatibility, three new actively cooled antennas are being designed, with the aim of reducing their sensitivity to the load variations induced by ELMs. The LH system has been recently upgraded with new klystrons and the PAM antenna, the possible reshaping of the antenna mouths is presently studied for matching with the magnetic field line in the WEST configuration. For the ECRH system, the device for the poloidal movement of the mirrors of the antenna is being changed for higher accuracy and speed.

  6. A brief history of high power RF proton linear accelerators

    SciTech Connect (OSTI)

    Browne, J.C.

    1996-12-31T23:59:59.000Z

    The first mention of linear acceleration was in a paper by G. Ising in 1924 in which he postulated the acceleration of positive ions induced by spark discharges which produced electric fields in gaps between a series of {open_quotes}drift tubes{close_quotes}. Ising apparently was not able to demonstrate his concept, most likely due to the limited state of electronic devices. Ising`s work was followed by a seminal paper by R. Wideroe in 1928 in which he demonstrated the first linear accelerator. Wideroe was able to accelerate sodium or potassium ions to 50 keV of energy using drift tubes connected alternately to high frequency waves and to ground. Nuclear physics during this period was interested in accelerating protons, deuterons, electrons and alpha particles and not heavy ions like sodium or potassium. To accelerate the light ions required much higher frequencies than available at that time. So linear accelerators were not pursued heavily at that time. Research continued during the 1930s but the development of high frequency RF tubes for radar applications in World War 2 opened the potential for RF linear accelerators after the war. The Berkeley laboratory of E. 0. Lawrence under the leadership of Luis Alvarez developed a new linear proton accelerator concept that utilized drift tubes that required a full RF period to pass through as compared to the earlier concepts. This development resulted in the historic Berkeley 32 MeV proton linear accelerator which incorporated the {open_quotes}Alvarez drift tube{close_quotes} as the basic acceleration scheme using surplus 200 MHz radar components.

  7. Separation of Zirconium from Uranium in U-Zr Alloys Using a Chlorination Process

    E-Print Network [OSTI]

    Parkison, Adam J

    2013-06-04T23:59:59.000Z

    The fundamental behavior underpinning a new processing concept was demonstrated which is capable of separating uranium from zirconium in U-Zr alloys through the formation and selective volatilization of their respective chlorides. Bench...

  8. Separation of Zirconium from Uranium in U-Zr Alloys Using a Chlorination Process 

    E-Print Network [OSTI]

    Parkison, Adam J

    2013-06-04T23:59:59.000Z

    The fundamental behavior underpinning a new processing concept was demonstrated which is capable of separating uranium from zirconium in U-Zr alloys through the formation and selective volatilization of their respective chlorides. Bench...

  9. Low beryllium content Zr-based bulk metallic glass composite with plasticity and work hardenability

    SciTech Connect (OSTI)

    Zheng, Q., E-mail: qiangzheng616@hotmail.com, E-mail: dujuan@nimte.ac.cn [School of Materials Science and Engineering, Ningbo University of Technology, Ningbo, 315016, China and Ningbo Branch of China Academy of Ordnance Science, Ningbo, 315103 (China); Du, J., E-mail: qiangzheng616@hotmail.com, E-mail: dujuan@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, NIMTE, CAS, Ningbo 315201 (China)

    2014-01-28T23:59:59.000Z

    A modified Zr-based bulk metallic glass matrix composite Zr{sub 47.67}Cu{sub 40}Ti{sub 3.66}Ni{sub 2.66}Be{sub 6} has been produced by increasing the contents of elements of Zr and Cu with higher Poisson ratio and reducing the contents of Ti, Ni, and Be elements with lower Poisson ratio based on famous metallic glass former Vitreloy 1. A compressive yielding strength of 1804?MPa, fracture strength of 1938?MPa and 3.5% plastic strain was obtained for obtained metallic glass composite. Also, work-hardening behavior was observed during compressive experiment which was ascribed to the interaction of the in situ precipitated CuZr phase and shear bands.

  10. Atomistic Modeling of Displacement Cascades in La2Zr2O7 Pyrochlore...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    static calculations. Citation: Chartier A, C Meis, JP Crocombette, LR Corrales, and WJ Weber.2003."Atomistic Modeling of Displacement Cascades in La2Zr2O7 Pyrochlore."Physical...

  11. A DFT + U study of cerium solubility in LaZrO. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    solution exhibits a reduced charge state. Citation: Wang XJ, HY Xiao, X Zu, and WJ Weber.2012."A DFT + U study of cerium solubility in La?Zr?O?."Journal of Nuclear Materials...

  12. Phase formation in Zr/Fe multilayers during Kr ion irradiation.

    SciTech Connect (OSTI)

    Motta, A. T.

    1998-01-29T23:59:59.000Z

    A detailed study has been conducted of the effect of Kr ion irradiation on phase formation in Zr-Fe metallic multilayers, using the Intermediate Voltage Electron Microscopy (IVEM) at Argonne National Laboratory. Metallic multilayers were prepared with different overall compositions (near 50-50 and Fe-rich), and with different wavelengths (repetition thicknesses). These samples were irradiated with 300 keV Kr ions at various temperatures to investigate the final products, as well as the kinetics of phase formation. For the shorter wavelength samples, the final product was in all cases an amorphous Zr-Fe phase, in combination with Fe, while specially for the larger wavelength samples, in the Fe-rich samples the intermetallic compounds ZrFe{sub 2} and Zr{sub 3}Fe were formed in addition to the amorphous phase. The dose to full reaction decreases with temperature, and with wavelength in a manner consistent with a diffusion-controlled reaction.

  13. Beam dynamics studies for transverse electromagnetic mode type rf deflectors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ahmed, Shahid; Krafft, Geoffrey A.; Deitrick, Kirsten; De Silva, Subashini U.; Delayen, Jean R.; Spata, Mike; Tiefenback, Michael; Hofler, Alicia; Beard, Kevin

    2012-02-01T23:59:59.000Z

    We have performed three-dimensional simulations of beam dynamics for transverse electromagnetic mode (TEM) type rf deflectors: normal and superconducting. The compact size of these cavities as compared to the conventional TM110 type structures is more attractive particularly at low frequency. Highly concentrated electromagnetic fields between the parallel bars provide strong electrical stability to the beam for any mechanical disturbance. An array of six 2-cell normal conducting cavities or a single cell superconducting structure is enough to produce the required vertical displacement at the target point. Both the normal and superconducting structures show very small emittance dilution due to the vertical kick of the beam.

  14. Doped H(2)-Filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Johnson, R.P.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia; Rose, D.V.; /Voss Sci., Albuquerque

    2009-05-01T23:59:59.000Z

    RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF{sub 6} dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF{sub 6} doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants.

  15. THERMAL MODELING OF ION EXCHANGE COLUMNS WITH SPHERICAL RF RESIN

    SciTech Connect (OSTI)

    Lee, S.; King, W.

    2009-12-30T23:59:59.000Z

    Models have been developed to simulate the thermal performance of RF columns fully loaded with radioactive cesium. Temperature distributions and maximum temperatures across the column were calculated during Small Column Ion Exchange (SCIX) process upset conditions with a focus on implementation at Hanford. A two-dimensional computational modeling approach was taken to include conservative, bounding estimates for key parameters such that the results will provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on RF. The current full-scale design for the SCIX system includes a central cooling tube, and one objective of these calculations was to examine its elimination to simplify the design. Results confirmed that a column design without a central cooling tube is feasible for RF, allowing for the possibility of significant design simplifications if it can be assumed that the columns are always filled with liquid. With active cooling through the four outer tubes, the maximum column diameter expected to maintain the temperature below the assumed media and safety limits is 26 inches, which is comparable to the current design diameter. Additional analysis was conducted to predict the maximum column temperatures for the previously unevaluated accident scenario involving inadvertent drainage of liquid from a cesium-saturated column, with retention of the ion exchange media and cesium in the column. As expected, much higher maximum temperatures are observed in this case due to the poor heat transfer properties of air versus liquid. For this hypothetical accident scenario involving inadvertent and complete drainage of liquid from a cesium-saturated column, the modeling results indicate that the maximum temperature within a 28 inch diameter RF column with external cooling is expected to exceed 250 C within 2 days, while the maximum temperature of a 12 inch column is maintained below 100 C. In addition, the calculation results demonstrate that the cooling tube system external to an air-filled column is not highly effective at reducing the maximum temperature, but the baseline design using a central cooling tube inside the column provides sufficient cooling to maintain the maximum temperature near the assumed safety limit.

  16. Surface Characterization of the LCLS RF Gun Cathode

    SciTech Connect (OSTI)

    Brachmann, Axel; /SLAC; Decker, Franz-Josef; /SLAC; Ding, Yuantao; /SLAC; Dowell, David; /SLAC; Emma, Paul; /SLAC; Frisch, Josef; /SLAC; Gilevich, Sasha; /SLAC; Hays, Gregory; /SLAC; Hering, Philippe; /SLAC; Huang, Zhirong; /SLAC; Iverson, Richard; /SLAC; Loos, Henrik; /SLAC; Miahnahri, Alan; /SLAC; Nordlund, Dennis; /SLAC; Nuhn, Heinz-Dieter; /SLAC; Pianetta, Piero; /SLAC; Turner, James; /SLAC; Welch, James; /SLAC; White, William; /SLAC; Wu, Juhao; /SLAC; Xiang, Dao; /SLAC

    2012-06-25T23:59:59.000Z

    The first copper cathode installed in the LCLS RF gun was used during LCLS commissioning for more than a year. However, after high charge operation (> 500 pC), the cathode showed a decline of quantum efficiency within the area of drive laser illumination. They report results of SEM, XPS and XAS studies that were carried out on this cathode after it was removed from the gun. X-ray absorption and X-ray photoelectron spectroscopy reveal surface contamination by various hydrocarbon compounds. In addition they report on the performance of the second installed cathode with emphasis on the spatial distribution of electron emission.

  17. The modeling of RF stacking of protons in the Accumulator

    SciTech Connect (OSTI)

    Yoon, Phil S.; /Fermilab /Rochester U.; McGinnis, David P.; Chou, Weiren; /Fermilab

    2005-06-01T23:59:59.000Z

    When the Run2 collider program is terminated in 2009, the present pbar source will be available for other usages. One possible application is to convert the Antiproton Accumulator to a proton accumulator so that the beam power from the Main Injector could be greatly enhanced [1]. The Accumulator has the unique feature of very large momentum acceptance. It is possible to stack 3-4 Booster batches in the longitudinal phase space before transferring them to the Main Injector or Recycler. This note shows the simulation of RF stacking using the code ESME [2].

  18. RF Characterization of Niobium Films for Superconducting Cavities

    E-Print Network [OSTI]

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01T23:59:59.000Z

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  19. Superconducting DC and RF Properties of Ingot Niobium

    E-Print Network [OSTI]

    Dhakal, Pashupati; Kneisel, Peter; Myneni, Ganapati Rao

    2012-01-01T23:59:59.000Z

    The thermal conductivity, DC magnetization and penetration depth of large-grain niobium hollow cylindrical rods fabricated from ingots, manufactured by CBMM subjected to chemical and heat treatment were measured. The results confirm the influence of chemical and heat-treatment processes on the superconducting properties, with no significant dependence on the impurity concentrations in the original ingots. Furthermore, RF properties, such as the surface resistance and quench field of the niobium rods were measured using a TE011 cavity. The hollow niobium rod is the center conductor of this cavity, converting it to a coaxial cavity. The quench field is limited by the critical heat flux through the rods' cooling channel.

  20. Fabrication Processes for the PEP II RF Cavities

    SciTech Connect (OSTI)

    Franks, R.Mark; /LLNL, Livermore; Rimmer, Robert A.; /LBL, Berkeley; Schwarz, Heinz; /SLAC

    2011-09-01T23:59:59.000Z

    This paper presents the major steps used in the fabrication of the 26 RF Cavities required for the PEP-II B-factory. Several unique applications of conventional processes have been developed and successfully implemented: electron beam welding (EBW), with minimal porosity, of .75 inch (19 mm) copper cross-sections; extensive 5-axis milling of water channels; electroplating of .37 inch (10 mm) thick OFE copper; tuning of the cavity by profiling beam noses prior to final joining with the cavity body; and machining of the cavity interior, are described here.

  1. Measurement of current distribution on RF coils using MR imaging

    E-Print Network [OSTI]

    Wu, Yu

    1993-01-01T23:59:59.000Z

    in Appendix A show the structure of these two coils. Coil 1 in Figure A. l is a simple square loop, and coil 3 in Figure A. 3 is a square loop with an inside square conductor which is designed to show the eddy current distribution induced by the outside RF...Hs that the eddy current induced on the inside square conductor is mainly distributed on the edges, but the current distribution on the outside loop is not significantly affected by the eddy current by comparing Figure 2. 4 with Figure 2. 2. Figure 2. 3 and 2. 5...

  2. Index of /research/alcator/facility/Procedures/RF

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn Other News CommunityPortal8mse-solidedgeLH [ICO]RF [ICO]

  3. Microsoft PowerPoint - rf_5year_review

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE SWPA / SPRAresults from phasedKenneth7, 2007RF

  4. Atomic Layer Deposition of HfO2 Thin Films on Si and GaAs Substrates Justin C Hackley1

    E-Print Network [OSTI]

    Gougousi, Theodosia

    that have shown efficient growth of HfO2 films on Si-H at 100°C using amide precursors and heavy water.4 Hf and Materials Research Directorate, Army Research Laboratory, Aberdeen Proving Ground, MD, 21005-5069 ABSTRACT dielectrics in Metal Oxide Semiconductor Field Effect Transistors (MOSFET).5 However, one of the major issues

  5. Process and properties of electroless Ni-Cu-P-ZrO{sub 2} nanocomposite coatings

    SciTech Connect (OSTI)

    Ranganatha, S. [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India)] [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India); Venkatesha, T.V., E-mail: drtvvenkatesha@yahoo.co.uk [Department of Studies in Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta 577451, Shimoga, Karnataka (India); Vathsala, K. [Nanotribology Laboratory, Mechanical engineering department, Indian Institute of Science, Bangalore (India)] [Nanotribology Laboratory, Mechanical engineering department, Indian Institute of Science, Bangalore (India)

    2012-03-15T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer The Ni-P and Ni-P-Cu-ZrO{sub 2} coatings were produced by electroless technique. Black-Right-Pointing-Pointer The influence of copper and ZrO{sub 2} nanoparticles on Ni-P was studied. Black-Right-Pointing-Pointer Surface morphology, structure and electrochemical behavior were evaluated. Black-Right-Pointing-Pointer The Ni-Cu-P-ZrO{sub 2} and Ni-P-ZrO{sub 2} coatings are more resistant to corrosion than Ni-P. Black-Right-Pointing-Pointer Introduction of Cu and ZrO{sub 2} in the matrix aids to the enhancement of microhardness. -- Abstract: Electroless Ni-Cu-P-ZrO{sub 2} composite coating was successfully obtained on low carbon steel matrix by electroless plating technique. Coatings with different compositions were obtained by varying copper as ternary metal and nano sized zirconium oxide particles so as to obtain elevated corrosion resistant Ni-P coating. Microstructure, crystal structure and composition of deposits were analyzed by SEM, EDX and XRD techniques. The corrosion behavior of the deposits was studied by anodic polarization, Tafel plots and electrochemical impedance spectroscopy (EIS) in 3.5% sodium chloride solution. The ZrO{sub 2} incorporated Ni-P coating showed higher corrosion resistance than plain Ni-P. The introduction of copper metal into Ni-P-ZrO{sub 2} enhanced the protection ability against corrosion. The influence of copper metal and nanoparticles on microhardness of coatings was evaluated.

  6. Deposition and characterization of TiZrV-Pd thin films by dc magnetron sputtering

    E-Print Network [OSTI]

    Wang, Jie; Xu, Yan-Hui; Wei, Wei; Fan, Le; Pei, Xiang-Tao; Hong, Yuan-Zhi; Wang, Yong

    2015-01-01T23:59:59.000Z

    TiZrV film is mainly applied in the ultra-high vacuum pipe of storage ring. Thin film coatings of palladium which was added onto the TiZrV film to increase the service life of nonevaporable getters and enhance pumping speed for H2, was deposited on the inner face of stainless steel pipes by dc magnetron sputtering using argon gas as the sputtering gas. The TiZrV-Pd film properties were investigated by atomic force microscope (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-Ray Diffraction (XRD). The grain size of TiZrV and Pd film were about 0.42~1.3 nm and 8.5~18.25 nm respectively. It was found that the roughness of TiZrV films was small, about 2~4 nm, for Pd film it is large, about 17~19 nm. PP At. % of Pd in TiZrV/Pd films varied from 86.84 to 87.56 according to the XPS test results.

  7. Results from ORNL Characterization of Zr02-500-AK2 - Surrogate TRISO Material

    SciTech Connect (OSTI)

    Hunn, John D [ORNL; Kercher, Andrew K [ORNL

    2005-06-01T23:59:59.000Z

    This document is a compilation of the characterization data for the TRISO-coated surrogate particle batch designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the createion of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significanly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  8. Results from ORNL characterization of ZrO2-500-AK2 - surrogate TRISO material

    SciTech Connect (OSTI)

    Kercher, Andrew K [ORNL; Hunn, John D [ORNL

    2005-06-01T23:59:59.000Z

    This document is a compilation of the characterization data for the TRISO-coated surrogate particles designated ZrO2-500-AK2 that was produced at Oak Ridge National Laboratory (ORNL) as part of the Advanced Gas Reactor Fuel Development and Qualification (AGR) program. The ZrO2-500-AK2 material contains nominally 500 {micro}m kernels of yttria-stabilized zirconia (YSZ) coated with all TRISO layers (buffer, inner pyrocarbon, silicon carbide, and outer pyrocarbon). The ZrO2-500-AK2 material was created for: (1) irradiation testing in the High Flux Isotope Reactor (HFIR) and (2) limited dissemination to laboratories as deemed appropriate to the AGR program. This material was created midway into a TRISO fuel development program to accommodate a sudden opportunity to perform irradiation testing on surrogate material. While the layer deposition processes were chosen based on the best technical understanding at the time, technical progress at ORNL has led to an evolution in the perceived optimal deposition conditions since the creation of ZrO2-500-AK2. Thus, ZrO2-500-AK2 contains a reasonable TRISO microstructure, but does differ significantly from currently produced TRISO surrogates and fuel at ORNL. In this document, characterization data of the ZrO2-500-AK2 surrogate includes: size, shape, coating thickness, and density.

  9. Infrared study on room-temperature atomic layer deposition of HfO{sub 2} using tetrakis(ethylmethylamino)hafnium and remote plasma-excited oxidizing agents

    SciTech Connect (OSTI)

    Kanomata, Kensaku [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan and Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Ohba, Hisashi; Pungboon Pansila, P.; Ahmmad, Bashir; Kubota, Shigeru; Hirahara, Kazuhiro; Hirose, Fumihiko, E-mail: fhirose@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2015-01-01T23:59:59.000Z

    Room-temperature atomic layer deposition (ALD) of HfO{sub 2} was examined using tetrakis (ethylmethylamino)hafnium (TEMAH) and remote plasma-excited water and oxygen. A growth rate of 0.26?nm/cycle at room temperature was achieved, and the TEMAH adsorption and its oxidization on HfO{sub 2} were investigated by multiple internal reflection infrared absorption spectroscopy. It was observed that saturated adsorption of TEMAH occurs at exposures of ?1?×?10{sup 5}?L (1 L?=?1?×?10{sup ?6} Torr s) at room temperature, and the use of remote plasma-excited water and oxygen vapor is effective in oxidizing the TEMAH molecules on the HfO{sub 2} surface, to produce OH sites. The infrared study suggested that Hf–OH plays a role as an adsorption site for TEMAH. The reaction mechanism of room temperature HfO{sub 2} ALD is discussed in this paper.

  10. DC and RF Measurements of Serial Bi-SQUID Arrays

    E-Print Network [OSTI]

    Prokopenko, G V; de Escobar, A Leese; Taylor, B; de Andrade, M C; Berggren, S; Longhini, P; Palacios, A; Nisenoff, M; Fagaly, R L

    2012-01-01T23:59:59.000Z

    SQUID arrays are promising candidates for low profile antennas and low noise amplifier applications. We present the integrated circuit designs and results of DC and RF measurements of the wideband serial arrays based on integration of linear bi-SQUID cells forming a Superconducting Quantum Interference Filter (bi-SQUID SQIF). Various configurations of serial arrays designs are described. The measured linearity, power gain, and noise temperature are analyzed and compared. The experimental results are matched to results of mathematical modeling. A serial bi-SQUID SQIF arrays are mounted into a coplanar waveguide (CPW) and symmetrically grounded to corresponding sides of CPW. The RF output comes out from the central common line, which is also used for DC biasing and forms a symmetrical balanced output. The signal and DC flux biasing line is designed as coplanar lines passed in parallel over each bi-SQUID cell in a bidirectional fashion concentrating magnetic flux inside of each cell. Serial bi-SQUID SQIF arrays ...

  11. System studies of rf current drive for MST

    SciTech Connect (OSTI)

    Anderson, J. K.; Burke, D. R.; Forest, C. B.; Goetz, J. A.; Hendries, E. R.; Seltzman, A. H.; Thomas, M. A. [Department of Physics, University of Wisconsin, Madison, WI (United States); Diem, S. [Oak Ridge National Laboratory, Oak Ridge TN (United States); Harvey, R. W. [CompX, Del Mar, CA (United States); Kaufman, M. C. [Department of Physics, University of Wisconsin, Madison, WI (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2011-12-23T23:59:59.000Z

    Two rf schemes are being studied on the MST reversed field pinch for their potential in current profile control experiments. MHD modeling has shown that a substantial externally-driven off axis parallel current can improve stability of the dominant core tearing modes. A radially localized axisymmetric population of fast electrons has been observed by SXR emission during LH injection (100kW at 800MHz), and is consistent with CQL3D modeling which predicts a small driven current. Computational work suggests that doubling the input power will statistically improve the LH-induced SXR signal to background ratio, and that about 2MW of injected power (an order of magnitude increase) will drive enough current for stabilization of tearing modes. Additionally, a 1 MW 5.5 GHz electron Bernstein wave (EBW) experiment is under construction, which utilizes a very simple and compact antenna compatible with the demands of the RFP. EBW allows access to electron cyclotron heating and current drive in the overdense plasma. Coupling of the external electromagnetic wave to the EBW has been demonstrated, and initial tests at {approx}100kW power have produced a small, localized xray flux consistent with rf heating and high diffusivity of fast electrons. Computational work is currently underway to answer the very important questions of how much power is required, and what level of electron diffusivity is tolerable, to generate a consequential amount of EBW current.

  12. Gas-phase hydrogen isotope exchange in HF + D2O

    SciTech Connect (OSTI)

    Trowbridge, L.D.

    1982-12-31T23:59:59.000Z

    The gas-phase isotope exchange reaction of HF and D2O has been studied by flow tube and matrix isolation techniques over a range of concentrations and reaction times. The matrix isolation/FTIR gas sampling and analysis technique proved capable of detecting reactants and products even at low concentrations (0.02% and less) and for reaction times down to 10 msec. The reaction under study, however, is sufficiently rapid that it appeared complete at 10 msec even at the lowest reactant concentrations used. From these results, it is therefore possible only to place a lower bound on the reaction rate. This lower bound, arrived at by computer modeling an assumed second order reaction in the flow tube, represents a refinement in the previously established limit by about a factor of 10U and may thus be of utility in UF6 atmospheric release models. 4 refs., 13 figs., 2 tabs.

  13. Analytical Potential Energy Surface for the Na + HF NaF + H reaction: Application of Conventional Transition-State Theory

    E-Print Network [OSTI]

    Analytical Potential Energy Surface for the Na + HF NaF + H reaction: Application of Conventional Transition-State Theory Alessandra F. A. Vilela, Ricardo Gargano a Patr´icia R.P. Barreto b a Instituto de from calculation of the rate constant using con- ventional Transition State Theory (TST

  14. Analysis of Ti-Ni-Hf shape memory alloys by combinatorial nanocalorimetry Yahya Motemani1,2

    E-Print Network [OSTI]

    1 Analysis of Ti-Ni-Hf shape memory alloys by combinatorial nanocalorimetry Yahya Motemani1 memory alloy. #12;3 1. Introduction Many titanium-nickel based alloys display shape memory behavior) and a low- temperature monoclinic phase (martensite). The shape memory behavior, along with good

  15. NEW ACTIVE LOAD VOLTAGE CLAMP FOR HF-LINK CONVERTERS Petar Ljusev and Michael A.E. Andersen

    E-Print Network [OSTI]

    that incorporates both the main power and auxiliary transformer on the same magnetic core. Keywords: HF not need additional power components, but do have increased control complexity and safety problems. The latter solutions satisfy both the commutation and safety issues, but ask for additional power components

  16. Computer simulations for direct conversion of the HF electromagnetic wave into the upper hybrid wave in ionospheric heating experiments

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Computer simulations for direct conversion of the HF electromagnetic wave into the upper hybrid emissions (SEE). A direct conversion process is proposed as an excitation mech- anism of the upper hybrid, 1996) The electrostatic waves at the UH resonance were assumed to be excited via ``direct conversion

  17. Computational investigation of the phase stability and the electronic properties for Gd-doped HfO{sub 2}

    SciTech Connect (OSTI)

    Wang, L. G. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); California Institute of Technology, Pasadena, California 91125 (United States); Xiong, Y.; Xiao, W.; Cheng, L.; Du, J.; Tu, H. [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Walle, A. van de [Brown University, Providence, Rhode Island 02912 (United States); California Institute of Technology, Pasadena, California 91125 (United States)

    2014-05-19T23:59:59.000Z

    Rare earth doping is an important approach to improve the desired properties of high-k gate dielectric oxides. We have carried out a comprehensive theoretical investigation on the phase stability, band gap, formation of oxygen vacancies, and dielectric properties for the Gd-doped HfO{sub 2}. Our calculated results indicate that the tetragonal phase is more stable than the monoclinic phase when the Gd doping concentration is greater than 15.5%, which is in a good agreement with the experimental observations. The dopant's geometric effect is mainly responsible for the phase stability. The Gd doping enlarges the band gap of the material. The dielectric constant for the Gd-doped HfO{sub 2} is in the range of 20–30 that is suitable for high-k dielectric applications. The neutral oxygen vacancy formation energy is 3.2?eV lower in the doped material than in pure HfO{sub 2}. We explain the experimental observation on the decrease of photoluminescence intensities in the Gd-doped HfO{sub 2} according to forming the dopant-oxygen vacancy complexes.

  18. Role of hydrogen in Ge/HfO2/Al gate stacks subjected to negative bias temperature instability

    E-Print Network [OSTI]

    Misra, Durgamadhab "Durga"

    Role of hydrogen in Ge/HfO2/Al gate stacks subjected to negative bias temperature instability N 2007; published online 17 January 2008 This work investigates the role of hydrogen and nitrogen in a Ge. Virtually unchanged interface state density as a function of NBTI indicates no atomic hydrogen release from

  19. Characterization of a high temperature superconducting oxide thin-film RF SQUID

    SciTech Connect (OSTI)

    Daly, K.P.; Silver, A.H.; Simon, R.W.; Platt, C.E.; Lee, A.E.; Wire, M.S.; Zimmerman, J.E.

    1989-03-01T23:59:59.000Z

    The authors have successfully fabricated and operated RF SQUIDS made from thin-films of the high temperature superconducting oxide ErBa/sub 2/Cu/sub 3/O/sub 7-x/. The ideal triangular quantum interference pattern characteristic of RF SQUIDS is observed. The performance of a particular device, operating between 60 and 65K, is described in detail.

  20. Green radio despite "Dirty RF" front-end Myriam Ariaudo*1

    E-Print Network [OSTI]

    Fijalkow, Inbar

    Green radio despite "Dirty RF" front-end Myriam Ariaudo*1 , Inbar Fijalkow1 , Jean-Luc Gautier1 in order to contribute in a Green radio development. In fact, the effects of typical RF imperfections, like algorithms are applied. Such algorithms enable Green applications (e.g., Orthogonal Frequency Division

  1. Porkolab@DPP-LA-2001 Waves and RF Heating in Plasmas

    E-Print Network [OSTI]

    (interface with technology) #12;Porkolab@DPP-LA-2001 RF Heating in Plasmas-circa 1950s The "Primitive" DaysPorkolab@DPP-LA-2001 Waves and RF Heating in Plasmas: a Historical Perspective Miklos Porkolab MIT wave propagation physics · 1980's: ICRF heating works at the multi-MW level! LH Current Drive

  2. Study of high pressure gas filled RF cavities for muon collider

    E-Print Network [OSTI]

    Yonehara, Katsuya

    2015-01-01T23:59:59.000Z

    Muon collider is a considerable candidate of the next-generation high-energy lepton collider machine. Operating an RF cavity in a multi-Tesla magnet is a critical requirement in a muon accelerator and a cooling channel. However, the maximum RF gradient in a vacuum RF cavity is strongly limited by an external magnetic field. Dense hydrogen gas filled RF cavity has been proposed since it is functional of generating a high RF accelerating gradient in a strong magnetic field and making an ionization cooling process at the same time. A critical issue of the cavity is a beam- induced plasma that consumes a considerable amount of RF power. The gas filled RF test cell was made and measured the RF loading due to a beam-induced plasma by using an intense proton beam at Fermilab. By doping an electronegative gas in dense hydrogen, the plasma loading effect is significantly mitigated. The result shows that the cavity is functional with a muon collider beam. Recent progress is shown in this presentation.

  3. SYNTHESIS OF ZINC FERRITE NANOPOWDERS IN AN RF THERMAL PLASMA , J. Szpvlgyi1

    E-Print Network [OSTI]

    Gubicza, Jenõ

    SYNTHESIS OF ZINC FERRITE NANOPOWDERS IN AN RF THERMAL PLASMA I. Mohai1 , J. Szépvölgyi1 , J University, P.O.B. 32, Budapest, H-1518, Hungary Abstract Nanosized zinc ferrite spinel powders of various. Ferrites synthetized in the RF plasma reactor were compared to that produced by the conventional ceramic

  4. Study of lithium diffusion in RF sputtered Nickel/Vanadium mixed oxides thin films

    E-Print Network [OSTI]

    Artuso, Florinda

    Study of lithium diffusion in RF sputtered NickelÁ/Vanadium mixed oxides thin films F. Artuso a lithium insertion inside RF sputtered Ni/V mixed oxides thin films have been investigated employing, showed three steps clearly involved in the intercalation mechanism of lithium in the oxide films: (i

  5. WORLD RECORD ACCELERATING GRADIENT ACHIEVED IN A SUPERCONDUCTING NIOBIUM RF CAVITY

    E-Print Network [OSTI]

    Geng, Rong-Li

    WORLD RECORD ACCELERATING GRADIENT ACHIEVED IN A SUPERCONDUCTING NIOBIUM RF CAVITY R.L. Geng On November 16, 2004, a CW accelerating gradient of 46 MV/m was achieved in a superconducting niobium cav- ity/m was achieved. This represents a world record gradient in a niobium RF resonator. At a reduced temperature of 1

  6. MIRCO-STRUCTURES OF RF SURFACES IN THE ELECTRON-BEAM-WELD REGIONS OF NIOBIUM

    E-Print Network [OSTI]

    Geng, Rong-Li

    MIRCO-STRUCTURES OF RF SURFACES IN THE ELECTRON-BEAM-WELD REGIONS OF NIOBIUM R.L. Gengyz , J-structures of RF surfaces in the electron-beam-weld (EBW) regions of niobium samples were studied. These surfaces.These observations have important impli- cations in explanations of the high-field-Q-drop of niobium superconducting

  7. Power Reduction of CMP Communication Networks via RF-Interconnects M-C. Frank Chang

    E-Print Network [OSTI]

    Cong, Jason "Jingsheng"

    latency and low energy consumption [5][7]. RF-I transmission lines provide single-cycle crossPower Reduction of CMP Communication Networks via RF-Interconnects M-C. Frank Chang , Jason Cong}@cs.ucla.edu Electrical Engineering Department, UCLA. {mfchang, socher, roccotam}@ee.ucla.edu Abstract As chip

  8. An All Metal High Power Circularly Polarized 100 MW RF Load

    SciTech Connect (OSTI)

    Fowkes, W.R.; Jongewaard, E.N.; Loewen, R.J.; Tantawi, S.G.; Vlieks, A.E.; /SLAC

    2011-08-30T23:59:59.000Z

    A compact RF load has been designed using a cascaded array of lossy radial RF chokes to dissipate 100 MW peak and 8 kW average power uniformly along the length of the load. Operation in the circularly polarized Te{_}11 mode assures uniform dissipation azimuthally as well.

  9. RF propagation in an HVAC duct system: impulse response characteristics of the channel

    E-Print Network [OSTI]

    Stancil, Daniel D.

    RF propagation in an HVAC duct system: impulse response characteristics of the channel Pavel V, the heating, ventilation, and air conditioning (HVAC) duct system in buildings is a complex network of hollow at RF and microwave frequencies of com- mon interest. HVAC ducts can be used as a wireless communication

  10. Automatic generation of RF compact models from device simulation S. Luryi and A. Pacelli

    E-Print Network [OSTI]

    Luryi, Serge

    , parasitic elements, and complex physical effects such as self- heating and hot-carrier transport. Keywords: Compact models; device simulation; RF; inter- connects; self-heating 1 INTRODUCTION Conventional RF of Electrical and Computer Engineering State University of New York, Stony Brook, NY 11794-2350, (serge

  11. Dependence of nuclear spin singlet lifetimes on RF spin-locking power

    E-Print Network [OSTI]

    Stephen J. DeVience; Ronald L. Walsworth; Matthew S. Rosen

    2012-01-06T23:59:59.000Z

    We measure the lifetime of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field and present a simple theoretical model that agrees well with our measurements, including the low-RF-power regime. We also measure the lifetime of a long-lived coherence between singlet and triplet states that does not require a spin-locking field for preservation. Our results indicate that for many molecules, singlet states can be created using weak RF spin-locking fields: more than two orders of magnitude lower RF power than in previous studies. Our findings suggest that in many biomolecules, singlets and related states with enhanced lifetimes might be achievable in vivo with safe levels of RF power.

  12. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, Eiichi (Los Alamos, NM); Roeder, Stephen B. W. (La Mesa, CA); Assink, Roger A. (Albuquerque, NM); Gibson, Atholl A. V. (Bryan, TX)

    1986-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  13. Determination of the direct double- ? -decay Q value of Zr 96 and atomic masses of Zr 90 - 92 , 94 , 96 and Mo 92 , 94 - 98 , 100

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gulyuz, K.; Ariche, J.; Bollen, G.; Bustabad, S.; Eibach, M.; Izzo, C.; Novario, S. J.; Redshaw, M.; Ringle, R.; Sandler, R.; Schwarz, S.; Valverde, A. A.

    2015-05-01T23:59:59.000Z

    Experimental searches for neutrinoless double-? decay offer one of the best opportunities to look for physics beyond the standard model. Detecting this decay would confirm the Majorana nature of the neutrino, and a measurement of its half-life can be used to determine the absolute neutrino mass scale. Important to both tasks is an accurate knowledge of the Q value of the double-? decay. The LEBIT Penning trap mass spectrometer was used for the first direct experimental determination of the ??Zr double-? decay Q value: Q??=3355.85(15) keV. This value is nearly 7 keV larger than the 2012 Atomic Mass Evaluation [M. Wang et al., Chin. Phys. C 36, 1603 (2012)] value and one order of magnitude more precise. The 3-? shift is primarily due to a more accurate measurement of the ??Zr atomic mass: m(??Zr)=95.90827735(17) u. Using the new Q value, the 2???-decay matrix element, |M2?|, is calculated. Improved determinations of the atomic masses of all other zirconium (90-92,94,96Zr) and molybdenum (92,94-98,100Mo) isotopes using both ¹²C? and ??Rb as references are also reported.

  14. rf power system for thrust measurements of a helicon plasma source Alexander W. Kieckhafer and Mitchell L. R. Walker

    E-Print Network [OSTI]

    Walker, Mitchell

    rf power system for thrust measurements of a helicon plasma source Alexander W. Kieckhafer measurement stand and showed that rf power has no statistically significant contribution to the thrust stand now, a true thrust diagnostic that can measure thrust of a rf device does not exist. A helicon plasma

  15. TESLA-FEL Report 2005-06 DIGITAL LOW LEVEL RF CONTROL SYSTEM FOR THE DESY TTF

    E-Print Network [OSTI]

    TESLA-FEL Report 2005-06 DIGITAL LOW LEVEL RF CONTROL SYSTEM FOR THE DESY TTF VUV-FEL LINAC Valeri Electron Laser (VUV-FEL) Linac each klystron supplies RF power to up to 32 cavities. The superconducting. The VUV-FEL Linac RF control system employs a completely digital feedback system to provide flexibility

  16. A new microphonics measurement method for superconducting RF cavities

    SciTech Connect (OSTI)

    Gao,Zheng; He,Yuan; Chang,Wei; Powers, Tom [JLAB; Yue,Wei-ming; Zhu,Zheng-long; Chen,Qi

    2014-09-01T23:59:59.000Z

    Mechanical vibrations of the superconducting cavity, also known as microphonics, cause shifts in the resonant frequency of the cavity. In addition to requiring additional RF power, these frequency shifts can contribute to errors in the closed loop phase and amplitude regulation. In order to better understand these effects, a new microphonics measurement method was developed, and the method was successfully used to measure microphonics on the half-wave superconducting cavity when it was operated in a production style cryostat. The test cryostat held a single ?=0.1 half-wave cavity which was operated at 162.5 MHz [1] and [2]. It's the first time that the National Instruments PXIe-5641R intermediate frequency transceiver has been used for microphonics measurements in superconducting cavities. The new microphonics measurement method and results will be shown and analyzed in this paper.

  17. Superconducting DC and RF Properties of Ingot Niobium

    SciTech Connect (OSTI)

    Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni

    2011-07-01T23:59:59.000Z

    The thermal conductivity, DC magnetization and penetration depth of large-grain niobium hollow cylindrical rods fabricated from ingots, manufactured by CBMM subjected to chemical and heat treatment were measured. The results confirm the influence of chemical and heat-treatment processes on the superconducting properties, with no significant dependence on the impurity concentrations in the original ingots. Furthermore, RF properties, such as the surface resistance and quench field of the niobium rods were measured using a TE{sub 011} cavity. The hollow niobium rod is the center conductor of this cavity, converting it to a coaxial cavity. The quench field is limited by the critical heat flux through the rods' cooling channel.

  18. Results of a preliminary, high power RF thruster test

    SciTech Connect (OSTI)

    Brewer, L.; Karras, T.; Frind, G.; Holmes, D.G.

    1989-01-01T23:59:59.000Z

    The objective of this program was to demonstrate a high power electrodeless, RF electric propulsion concept. This was successfully accomplished. No attempt was made to optimize the design of the thruster with regard to physical dimensions, mass flow, nozzle shape, operational frequency, or power level. Measurements made were chamber pressure, total and static pressures at the nozzle exit plane and exhaust tank pressure. Mass flows range from about 0.4 to 1 gm/sec and, assuming perfect gas relationships, specific impulses up to 580 sec were obtained. Typical chamber pressure was 300 torr exhausting to a tank pressure of about 10 torr. Working fluids used were argon, helium and mixtures of the two. No degration of the device was detected after 12 start/stop cycles, about three hours of total run time, and a maximum input power of 70 kW. 10 refs.

  19. Nanometer emittance ultralow charge beams from rf photoinjectors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, R. K.; Roberts, K. G.; Scoby, C. M.; To, H.; Musumeci, P.

    2012-09-01T23:59:59.000Z

    In this paper we discuss the generation of a new class of high brightness relativistic electron beams, characterized by ultralow charge (0.1–1 pC) and ultralow normalized emittance (<50??nm ). These beams are created in rf photoinjectors when the laser is focused on the cathode to very small transverse sizes (<30???m rms). In this regime, the charge density at the cathode approaches the limit set by the extraction electric field. By shaping the laser pulse to have a cigarlike aspect ratio (the longitudinal dimension much larger than the transverse dimension) and a parabolic temporal profile, the resulting space charge dominated dynamics creates a uniformly filled ellipsoidal distribution and the emittance can be nearly preserved to its thermal value. We also present a new method, based on a variation of the pepper-pot technique, for single shot measurements of the ultralow emittances for this new class of beams.

  20. National RF Test Facility as a multipurpose development tool

    SciTech Connect (OSTI)

    McManamy, T.J.; Becraft, W.R.; Berry, L.A.; Blue, C.W.; Gardner, W.L.; Haselton, H.H.; Hoffman, D.J.; Loring, C.M. Jr.; Moeller, F.A.; Ponte, N.S.

    1983-01-01T23:59:59.000Z

    Additions and modifications to the National RF Test Facility design have been made that (1) focus its use for technology development for future large systems in the ion cyclotron range of frequencies (ICRF), (2) expand its applicability to technology development in the electron cyclotron range of frequencies (ECRF) at 60 GHz, (3) provide a facility for ELMO Bumpy Torus (EBT) 60-GHz ring physics studies, and (4) permit engineering studies of steady-state plasma systems, including superconducting magnet performance, vacuum vessel heat flux removal, and microwave protection. The facility will continue to function as a test bed for generic technology developments for ICRF and the lower hybrid range of frequencies (LHRF). The upgraded facility is also suitable for mirror halo physics experiments.

  1. Cerenkov Radiator Driven by a Superconducting RF Electron Gun

    SciTech Connect (OSTI)

    Poole, B R; Harris, J R

    2011-03-07T23:59:59.000Z

    The Naval Postgraduate School (NPS), Niowave, Inc., and Boeing have recently demonstrated operation of the first superconducting RF electron gun based on a quarter wave resonator structure. In preliminary tests, this gun has produced 10 ps long bunches with charge in excess of 78 pC, and with beam energy up to 396 keV. Initial testing occurred at Niowave's Lansing, MI facility, but the gun and diagnostic beam line are planned for installation in California in the near future. The design of the diagnostic beam line is conducive to the addition of a Cerenkov radiator without interfering with other beam line operations. Design and simulations of a Cerenkov radiator, consisting of a dielectric lined waveguide will be presented. The dispersion relation for the structure is determined and the beam interaction is studied using numerical simulations. The characteristics of the microwave radiation produced in both the short and long bunch regimes will be presented.

  2. RF Design Optimization for New Injector Cryounit at CEBAF

    SciTech Connect (OSTI)

    Wang, Haipeng; Cheng, Guangfeng; Hannon, Fay E.; Hofler, Alicia S.; Kazimi, Reza; Preble, Joe; Rimmer, Robert A.

    2013-06-01T23:59:59.000Z

    A new injector superconducting RF (SRF) cryounit with one new 2-cell, B=0.6 cavity plus one refurbished 7-cell, B=0.97, C100 style cavity has been re-designed and optimized for the engineering compatibility of existing module for CEBAF operation. The optimization of 2-cell cavity shape for longitudinal beam dynamic of acceleration from 200keV to 533keV and the minimization of transverse kick due to the waveguide couplers to less than 1 mrad have been considered. Operating at 1497MHz, two cavities has been designed into a same footprint of CEBAF original quarter cryomodule to deliver an injection beam energy of 5MeV in less than 0.27{degree} rms bunch length and a maximum energy spread of 5keV.

  3. Kinetics of plasma electrons in static and rf fields

    SciTech Connect (OSTI)

    Ivanov, Y.A.; Lebedev, Y.A.; Polak, L.S.

    1980-01-01T23:59:59.000Z

    The effect of the frequency of the field producing a plasma on the isotropic part of the electron energy distribution is analyzed. Analytic solutions of the Boltzmann equation are derived for high-energy tail of the electron energy distribution for static and rf fields. The results show that the shape of the tail of the distribution can be effectively controlled by changing the ratio of the field frequency to the effective frequency with which electrons collide with heavy particles and by choosing the appropriate dependence of the cross section for elastic scattering of electrons by heavy particles on the electron energy (by appropriate choice of the gas from which the plasma is formed). These results agree with experimental results in the literature.

  4. Material Selection and Characterization for High Gradient RF Applications

    E-Print Network [OSTI]

    Arnau-Izquierdo, G; Heikkinen, S; Ramsvik, T; Sgobba, Stefano; Taborelli, M; Wuensch, W

    2007-01-01T23:59:59.000Z

    The selection of candidate materials for the accelerating cavities of the Compact Linear Collider (CLIC) is carried out in parallel with high power RF testing. The maximum DC breakdown field of copper, copper alloys, refractory metals, aluminium and titanium have been measured with a dedicated setup. Higher maximum fields are obtained for refractory metals and for titanium, which exhibits, however, important damages after conditioning. Fatigue behaviour of copper alloys has been studied for surface and bulk by pulsed laser irradiation and ultrasonic excitation, respectively. The selected copper alloys show consistently higher fatigue resistance than copper in both experiments. In order to obtain the best local properties in the device a possible solution is a bi-metallic assembly. Junctions of molybdenum and copper-zirconium UNS C15000 alloy, achieved by HIP (Hot Isostatic Pressing) diffusion bonding or explosion bonding were evaluated for their mechanical strength. The reliability of the results obtained wit...

  5. The Development of the Linac Coherent Light Source RF Gun

    E-Print Network [OSTI]

    Dowell, David H; Lewandowski, James; Limborg-Deprey, Cecile; Li, Zenghai; Schmerge, John; Vlieks, Arnold; Wang, Juwen; Xiao, Liling

    2015-01-01T23:59:59.000Z

    The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL). In addition to many other stringent requirements, the LCLS XFEL requires extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. This paper describes the analysis and design improvements of the BNL/SLAC/UCLA s-band gun leading to achievement of the LCLS performance goals.

  6. Melting temperatures of the ZrO{sub 2}-MOX system

    SciTech Connect (OSTI)

    Uchida, T.; Hirooka, S.; Kato, M.; Morimoto, K. [Japan Atomic Energy Agency, 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan); Sugata, H.; Shibata, K.; Sato, D. [Inspection Development Company, 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2013-07-01T23:59:59.000Z

    Severe accidents occurred at the Fukushima Daiichi Nuclear Power Plant Units 1-3 on March 11, 2011. MOX fuels were loaded in the Unit 3. For the thermal analysis of the severe accident, melting temperature and phase state of MOX corium were investigated. The simulated coriums were prepared from 4%Pu-containing MOX, 8%Pu-containing MOX and ZrO{sub 2}. Then X-ray diffraction, density and melting temperature measurements were carried out as a function of zirconium and plutonium contents. The cubic phase was observed in the 25%Zr-containing corium and the tetragonal phase was observed in the 50% and 75%Zr-containing coria. The lattice parameter and density monotonically changed with Pu content. Melting temperature increased with increasing Pu content; melting temperature were estimated to be 2932 K for 4%Pu MOX corium and 3012 K for 8%Pu MOX corium in the 25%ZrO{sub 2}-MOX system. The lowest melting temperature was observed for 50%Zr-containing corium. (authors)

  7. R&D activities on RF contacts for the ITER ion cyclotron resonance heating launcher

    E-Print Network [OSTI]

    Hillairet, Julien; Bamber, Rob; Beaumont, Bertrand; Bernard, Jean-Michel; Delaplanche, Jean-Marc; Durodié, Frédéric; Lamalle, Philippe; Lombard, Gilles; Nicholls, Keith; Shannon, Mark; Vulliez, Karl; Cantone, Vincent; Hatchressian, Jean-Claude; Lebourg, Philippe; Martinez, André; Mollard, Patrick; Mouyon, David; Pagano, Marco; Patterlini, Jean-Claude; Soler, Bernard; Thouvenin, Didier; Toulouse, Lionel; Verger, Jean-Marc; Vigne, Terence; Volpe, Robert

    2015-01-01T23:59:59.000Z

    Embedded RF contacts are integrated within the ITER ICRH launcher to allow assembling, sliding and to lower the thermo-mechanical stress. They have to withstand a peak RF current up to 2.5 kA at 55 MHz in steady-state conditions, in the vacuum environment of themachine.The contacts have to sustain a temperature up to 250{\\textdegree}Cduring several days in baking operations and have to be reliable during the whole life of the launcher without degradation. The RF contacts are critical components for the launcher performance and intensive R&D is therefore required, since no RF contactshave so far been qualified at these specifications. In order to test and validate the anticipated RF contacts in operational conditions, CEA has prepared a test platform consisting of a steady-state vacuum pumped RF resonator. In collaboration with ITER Organization and the CYCLE consortium (CYclotronCLuster for Europe), an R&D program has been conducted to develop RF contacts that meet the ITER ICRH launcher specification...

  8. Pressurized H_{2} rf Cavities in Ionizing Beams and Magnetic Fields

    SciTech Connect (OSTI)

    Chung, M.; et al.

    2013-10-01T23:59:59.000Z

    A major technological challenge in building a muon cooling channel is operating RF cavities in multi-tesla external magnetic fields. We report the first experimental characterization of a high pressure gas-filled 805 MHz RF cavity for use with intense ionizing beams and strong external magnetic fields. RF power consumption by beam-induced plasma was investigated with hydrogen and deuterium gases with pressures between 20 and 100 atm and peak RF gradients between 5 and 50 MV/m. The energy absorption per ion pair-RF cycle ranges from 10?18 to 10?16 J. The low pressure case agrees well with an analytical model based on electron and ion mobilities. Varying concentrations of oxygen gas were investigated to remove free electrons from the cavity and reduce the RF power consumption. Measurements of the electron attachment time to oxygen and rate of ion-ion recombination were also made. Additionally, we demonstrate the operation of the gas-filled RF cavity in a solenoidal field of up to 3 T, finding no major magnetic field dependence. These results indicate that a high pressure gas-filled cavity is potentially a viable technology for muon ionization cooling.

  9. Next Generation Fast RF Interlock Module and ATCA Adapter for ILC High Availability RF Test Station Demonstration

    SciTech Connect (OSTI)

    Larsen, R

    2009-10-17T23:59:59.000Z

    High availability interlocks and controls are required for the ILC (International Linear Collider) L-Band high power RF stations. A new F3 (Fast Fault Finder) VME module has been developed to process both fast and slow interlocks using FPGA logic to detect the interlock trip excursions. This combination eliminates the need for separate PLC (Programmable Logic Controller) control of slow interlocks. Modules are chained together to accommodate as many inputs as needed. In the next phase of development the F3's will be ported to the new industry standard ATCA (Advanced Telecom Computing Architecture) crate (shelf) via a specially designed VME adapter module with IPMI (Intelligent Platform Management Interface). The goal is to demonstrate auto-failover and hot-swap for future partially redundant systems.

  10. First-principles calculations have been performed to study the structural and electronic properties of pure and Y-doped cubic HfO2. It is found that Y dopant in cubic HfO2 can increase the stability relative to the monoclinic phase by decreasing the energ

    E-Print Network [OSTI]

    Gong, Xingao

    supercell 3) VO : c-HfO2 ­ a 3×3×3 supercell Exc: GGA Energy cutoff: 495eV Potential: ultrasoft Vanderbilt was performed at Shanghai Supercomputer Center and Supercomputer Center of Fudan and CCS. C-HfO2 #12;

  11. Remarkable Strontium B-Site Occupancy in Ferroelectric Pb(Zr1-xTix)O3 Solid Solutions Doped with Cryolite-Type Strontium Niobate

    E-Print Network [OSTI]

    Feltz, A.; Schmidt-Winkel, P.; Schossman, M.; Booth, C.H.; Albering, J.

    2007-01-01T23:59:59.000Z

    contains Lead-Titanium-Zirconium Oxide of Specificstructure such as lead zirconium titanium oxide Pb(Zr,Ti)O 3

  12. Excitation functions of the nat-Ta(p,x)178m2Hf and nat-W(p,x)178m2Hf reactions at energies up to 2600 MeV

    E-Print Network [OSTI]

    Titarenko, Yu E; Pavlov, K V; Titarenko, A Yu; Zhivun, V M; Chauzova, M V; Ignatyuk, A V; Mashnik, S G; Leray, S; Boudard, A; David, J -C; Mancusi, D; Cugnon, J; Yariv, Y; Nishihara, K; Matsuda, N; Kumawat, H; Stankovsky, A Yu

    2015-01-01T23:59:59.000Z

    Due to potential level of energy intensity 178m2Hf is an extremely interesting isomer. One possible way to produce this isomer is irradiation of nat-Ta or nat-W samples with high energy protons. Irradiation of nat-Ta and nat-W samples performed for other purposes provides an opportunity to study the corresponding reactions. This paper pre-sents the 178m2Hf independent production cross sections for both targets measured by the gamma-ray spectrometry method. The reaction excitation functions have been obtained for the proton energies from 40 up to 2600 MeV. The experimental results were compared with calculations by various versions of the intranuclear cascade model in the well-known codes: ISABEL, Bertini, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The isomer ratio for the nat-Ta(p,x)178m2Hf reaction is evaluated on the basis of the available data.

  13. Excitation functions of the nat-Ta(p,x)178m2Hf and nat-W(p,x)178m2Hf reactions at energies up to 2600 MeV

    E-Print Network [OSTI]

    Yu. E. Titarenko; V. F. Batyaev; K. V. Pavlov; A. Yu. Titarenko; V. M. Zhivun; M. V. Chauzova; A. V. Ignatyuk; S. G. Mashnik; S. Leray; A. Boudard; J. -C. David; D. Mancusi; J. Cugnon; Y. Yariv; K. Nishihara; N. Matsuda; H. Kumawat; A. Yu. Stankovsky

    2015-04-30T23:59:59.000Z

    Due to potential level of energy intensity 178m2Hf is an extremely interesting isomer. One possible way to produce this isomer is irradiation of nat-Ta or nat-W samples with high energy protons. Irradiation of nat-Ta and nat-W samples performed for other purposes provides an opportunity to study the corresponding reactions. This paper pre-sents the 178m2Hf independent production cross sections for both targets measured by the gamma-ray spectrometry method. The reaction excitation functions have been obtained for the proton energies from 40 up to 2600 MeV. The experimental results were compared with calculations by various versions of the intranuclear cascade model in the well-known codes: ISABEL, Bertini, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The isomer ratio for the nat-Ta(p,x)178m2Hf reaction is evaluated on the basis of the available data.

  14. Solid state RF power: The route to 1W per euro cent

    SciTech Connect (OSTI)

    Heid, Oliver [Siemens AG, Mozartstrasse 57, Erlangen (Germany)

    2013-04-19T23:59:59.000Z

    In most particle accelerators RF power is a decisive design constraint due to high costs and relative inflexibility of current electron beam based RF sources, i.e. Klystrons, Magnetrons, Tetrodes etc. At VHF/UHF frequencies the transition to solid state devices promises to fundamentally change the situation. Recent progress brings 1 Watt per Euro cent installed cost within reach. We present a Silicon Carbide semiconductor solution utilising the Solid State Direct Drive technology at unprecedented efficiency, power levels and power densities. The proposed solution allows retrofitting of existing RF accelerators and opens the route to novel particle accelerator concepts.

  15. RF-driven ion source with a back-streaming electron dump

    DOE Patents [OSTI]

    Kwan, Joe; Ji, Qing

    2014-05-20T23:59:59.000Z

    A novel ion source is described having an improved lifetime. The ion source, in one embodiment, is a proton source, including an external RF antenna mounted to an RF window. To prevent backstreaming electrons formed in the beam column from striking the RF window, a back streaming electron dump is provided, which in one embodiment is formed of a cylindrical tube, open at one end to the ion source chamber and capped at its other end by a metal plug. The plug, maintained at the same electrical potential as the source, captures these backstreaming electrons, and thus prevents localized heating of the window, which due to said heating, might otherwise cause window damage.

  16. Kinetic Modeling of the Effect of MAO/Zr Ratio and Chain Transfer to Aluminum in Zirconocene Catalyzed Propylene Polymerization

    E-Print Network [OSTI]

    Catalyzed Propylene Polymerization Bernabe Quevedo-Sanchez, Jessica F. Nimmons, E. Bryan Coughlin was developed to characterize metallocene-catalyzed propylene polymerization using two different catalyst systems: rac-Et(Ind)2ZrCl2/MAO (I/MAO) and rac-Et(4,7-Me2-1-Ind)2ZrCl2/MAO (II/MAO). Slurry propylene

  17. Precipitation and Thermal Fatigue in Ni-Ti-Zr Shape Memory Alloy Thin Films by Combinatorial nanoCalorimetry

    E-Print Network [OSTI]

    1 Precipitation and Thermal Fatigue in Ni-Ti-Zr Shape Memory Alloy Thin Films by Combinatorial nano Mongolia University of Technology Hohhot 010051, China Abstract: Thin-film samples of Ni-Ti-Zr shape memory the composition and the stress state of the shape memory phase. Thermal fatigue behavior, induced by thermal

  18. Creep strength of niobium alloys, Nb-1%Zr and PWC-11

    SciTech Connect (OSTI)

    Titran, R.H.

    1990-01-01T23:59:59.000Z

    A study is being conducted at NASA Lewis Research Center to determine the feasibility of using a carbide particle strengthened Nb-1% Zr base alloy to meet the anticipated temperature and creep resistance requirements of proposed near term space power systems. In order to provide information to aid in the determination of the suitability of the PWC-11 alloy as an alternative to Nb-1% Zr in space power systems this study investigated (1) the long-time high-vacuum creep behavior of the PWC-11 material and the Nb-1% Zr alloy, (2) the effect of prior stress-free thermal aging on this creep behavior, (3) the effect of electron beam (EB) welding on this creep behavior, and (4) the stability of creep strengthening carbide particles. 14 refs., 5 figs., 2 tabs.

  19. Properties of HfLaO MOS capacitor deposited on SOI with plasma enhanced atomic layer deposition

    SciTech Connect (OSTI)

    Wan, Wenyan; Cheng, Xinhong, E-mail: xh-cheng@mail.sim.ac.cn; Cao, Duo; Zheng, Li; Xu, Dawei; Wang, Zhongjian; Xia, Chao; Shen, Lingyan; Yu, Yuehui [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Changning Road 865, Shanghai 200050 (China); Shen, DaShen [Department of Electrical and Computer Engineering, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)

    2014-01-15T23:59:59.000Z

    Amorphous HfLaO dielectric film was successfully deposited on a silicon-on-insulator (SOI) substrate by plasma enhanced atomic layer deposition with in situ plasma treatment. The HfLaO film retained its insulating characteristics and is thermally stable even after annealing at 800?°C. The film has a dielectric constant of 27.3 and leakage of only 0.03?mA/cm{sup 2} at a gate bias of |Vg ? V{sub fb}|?=?1?V. The capacitance equivalent oxide thickness is 0.7?nm. A new parallel electrode testing structure was applied to measure C–V and J–V characteristics for the SOI samples. This testing method for metal–oxide–semiconductor capacitors has potential uses for measuring other layered substrates.

  20. The transition from amorphous to crystalline in Al/Zr multilayers

    SciTech Connect (OSTI)

    Zhong Qi; Zhang Zhong; Ma Shuang; Qi Runze; Li Jia; Wang Zhanshan [MOE Key Laboratory of Advanced Micro-Structured Materials, Institute of Precision Optical Engineering, Department of Physics, Tongji University, Shanghai 200092 (China); Le Guen, Karine; Andre, Jean-Michel; Jonnard, Philippe [Laboratoire de Chimie Physique - Matiere et Rayonnement, UPMC Univ. Paris 06, CNRS UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France)

    2013-04-07T23:59:59.000Z

    The amorphous-to-crystalline transition in Al(1.0%wtSi)/Zr and Al(Pure)/Zr multilayers grown by direct-current magnetron sputtering system has been characterized over a range of Al layer thicknesses (1.0-5.0 nm) by using a series of complementary measurements including grazing incidence X-ray reflectometry, atomic force microscopy, X-ray diffraction, and high-resolution transmission electron microscopy. The Al layer thickness transition exhibits the Si doped in Al could not only disfavor the crystallization of Al but also influence the changing trends of surface roughness and diffraction peak position of phase Al<111>. An interesting feature of the presence of Si in Al layer is that Si could influence the transition process in Al(1%wtSi) layer, in which the critical thickness (1.6 nm) of Al(Pure) layer in Al(Pure)/Zr shifts to 1.8 nm of Al(1.0%wtSi) layer in Al(1.0%wtSi)/Zr multilayer. We also found that the Zr-on-Al interlayer is wider than the Al-on-Zr interlayer in both systems, and the Al layers do not have specific crystal orientation in the directions vertical to the layer from selected area electron diffraction patterns below the thickness (3.0 nm) of Al layers. Above the thickness (3.0 nm) of Al layers, the Al layers are highly oriented in Al<111>, so that the transformation from asymmetrical to symmetrical interlayers can be observed. Based on the analysis of all measurements, we build up a model with four steps, which could explain the Al layer thickness transition process in terms of a critical thickness for the nucleation of Al(Pure) and Al(1%wtSi) crystallites.

  1. Experiments and theory on parametric instabilities excited in HF heating experiments at HAARP

    SciTech Connect (OSTI)

    Kuo, Spencer [New York University-Polytechnic School of Engineering, 5 Metrotech Center, Brooklyn, New York 11201 (United States); Snyder, Arnold [NorthWest Research Associates, P.O. Box 530, Stockton Springs, Maine 04981 (United States); Lee, M. C. [Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-06-15T23:59:59.000Z

    Parametric instabilities excited by O-mode HF heater and the induced ionospheric modification were explored via HAARP digisonde operated in a fast mode. The impact of excited Langmuir waves and upper hybrid waves on the ionosphere are manifested by bumps in the virtual spread, which expand the ionogram echoes upward as much as 140?km and the downward range spread of the sounding echoes, which exceeds 50?km over a significant frequency range. The theory of parametric instabilities is presented. The theory identifies the ionogram bump located between the 3.2?MHz heater frequency and the upper hybrid resonance frequency and the bump below the upper hybrid resonance frequency to be associated with the Langmuir and upper hybrid instabilities, respectively. The Langmuir bump is located close to the upper hybrid resonance frequency, rather than to the heater frequency, consistent with the theory. Each bump in the virtual height spread of the ionogram is similar to the cusp occurring in daytime ionograms at the E-F2 layer transition, indicating that there is a small ledge in the density profile similar to E-F2 layer transitions. The experimental results also show that the strong impact of the upper hybrid instability on the ionosphere can suppress the Langmuir instability.

  2. Band alignment between GaN and ZrO{sub 2} formed by atomic layer deposition

    SciTech Connect (OSTI)

    Ye, Gang; Wang, Hong, E-mail: ewanghong@ntu.edu.sg; Arulkumaran, Subramaniam; Ng, Geok Ing; Li, Yang; Ang, Kian Siong [Novitas, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Liu, Zhi Hong [Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602 (Singapore)

    2014-07-14T23:59:59.000Z

    The band alignment between Ga-face GaN and atomic-layer-deposited ZrO{sub 2} was investigated using X-ray photoelectron spectroscopy (XPS). The dependence of Ga 3d and Zr 3d core-level positions on the take-off angles indicated upward band bending at GaN surface and potential gradient in ZrO{sub 2} layer. Based on angle-resolved XPS measurements combined with numerical calculations, valence band discontinuity ?E{sub V} of 1?±?0.2?eV and conduction band discontinuity ?E{sub C} of 1.2?±?0.2?eV at ZrO{sub 2}/GaN interface were determined by taking GaN surface band bending and potential gradient in ZrO{sub 2} layer into account.

  3. Galactic Evolution of Sr, Y, Zr: A Multiplicity of Nucleosynthetic Processes

    E-Print Network [OSTI]

    Claudia Travaglio; Roberto Gallino; Enrico Arnone; John Cowan; Faith Jordan; Chris Sneden

    2003-10-07T23:59:59.000Z

    We follow the Galactic enrichment of three easily observed light n-capture elements Sr,Y,and Zr.Input stellar yields have been first separated into their respective main and weak s-process,and r-process components.The s-process yields from AGB stars are computed,exploring a wide range of efficiencies of the major neutron source,13C,and covering both disk and halo metallicities.AGBs have been shown to reproduce the main s-component in the solar system.The concurrent weak s-process,which accounts for the major fraction of the light s-process isotopes in the solar system and occurs in massive stars by the operation of the 22Ne n-source,is discussed in detail.Neither the main s-,nor the weak s-components are shown to contribute significantly to the n-capture element abundances observed in unevolved halo stars.We present a detailed analysis of a large database of spectroscopic observations of Sr,Y,Zr, Ba,and Eu for Galactic stars at various metallicities.Spectroscopic observations of Sr,Y,and Zr to Ba and Eu abundance ratios versus metallicity provide useful diagnostics of the types of n-capture processes forming Sr,Y and Zr.The observed [Sr,Y,Zr/Ba,Eu] ratio is clearly not flat at low metallicities,as we would expect if Ba,Eu and Sr,Y,Zr all had the same r-process origin.We discuss our chemical evolution predictions, taking into account the interplay between different processes to produce Sr-Y-Zr.We find hints for a primary process in low-metallicity massive stars, different from the 'classical s-process' and from the 'classical r-process',that we tentatively define LEPP (Lighter Element Primary Process).This allows us to revise the estimates of the r-process contributions to the solar Sr,Y and Zr abundances,as well as of the contribution to the s-only isotopes 86Sr,87Sr,96Mo.

  4. Physical properties of epitaxial ZrN/MgO(001) layers grown by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Mei, A. B.; Zhang, C.; Sardela, M.; Eckstein, J. N.; Rockett, A. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States); Howe, B. M. [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States)] [Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States); Hultman, L. [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J. E. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 and Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)

    2013-11-15T23:59:59.000Z

    Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, high-resolution cross-sectional transmission electron microscopy, and selected-area electron diffraction shows that ZrN grows epitaxially on MgO(001) with a cube-on-cube orientational relationship, (001){sub ZrN}?(001){sub MgO} and [100]{sub ZrN}?[100]{sub MgO}. The layers are essentially fully relaxed with a lattice parameter of 0.4575 nm, in good agreement with reported results for bulk ZrN crystals. X-ray reflectivity results reveal that the films are completely dense with smooth surfaces (roughness = 1.3 nm, consistent with atomic-force microscopy analyses). Based on temperature-dependent electronic transport measurements, epitaxial ZrN/MgO(001) layers have a room-temperature resistivity ?{sub 300K} of 12.0 ??-cm, a temperature coefficient of resistivity between 100 and 300 K of 5.6 × 10{sup ?8}?-cm K{sup ?1}, a residual resistivity ?{sub o} below 30 K of 0.78 ??-cm (corresponding to a residual resistivity ratio ?{sub 300?}/?{sub 15K} = 15), and the layers exhibit a superconducting transition temperature of 10.4 K. The relatively high residual resistivity ratio, combined with long in-plane and out-of-plane x-ray coherence lengths, ?{sub ?} = 18 nm and ?{sub ?} = 161 nm, indicates high crystalline quality with low mosaicity. The reflectance of ZrN(001), as determined by variable-angle spectroscopic ellipsometry, decreases slowly from 95% at 1 eV to 90% at 2 eV with a reflectance edge at 3.04 eV. Interband transitions dominate the dielectric response above 2 eV. The ZrN(001) nanoindentation hardness and modulus are 22.7 ± 1.7 and 450 ± 25 GPa.

  5. Features of the band structure and conduction mechanisms in the n-HfNiSn semiconductor heavily doped with Ru

    SciTech Connect (OSTI)

    Romaka, V. A., E-mail: vromaka@polynet.lviv.ua [National Academy of Sciences of Ukraine, Pidstrygach Institute for Applied Problems in Mechanics and Mathematics (Ukraine); Rogl, P. [Universität Wien, Institut für Physikalische Chemie (Austria); Romaka, V. V. [National University Lvivska Politekhnika (Ukraine); Stadnyk, Yu. V. [Ivan Franko National University of Lviv (Ukraine); Korzh, R. O.; Krayovskyy, V. Ya. [National University Lvivska Politekhnika (Ukraine); Horyn, A. M. [Ivan Franko National University of Lviv (Ukraine)

    2014-12-15T23:59:59.000Z

    The crystal and electronic structure and energy and kinetic properties of the n-HfNiSn semiconductor heavily doped with a Ru acceptor impurity are investigated in the temperature and Ru concentration ranges T = 80–400 K and N{sub A}{sup Ru} ? 9.5 × 10{sup 19}?5.7 × 10{sup 20} cm{sup ?3} (x = 0–0.03), respectively. The mechanism of structural-defect generation is established, which changes the band gap and degree of compensation of the semiconductor and consists in the simultaneous concentration reduction and elimination of donor structural defects by means of the displacement of ?1% of Ni atoms from the Hf (4a) positions, the generation of acceptor structural defects upon the substitution of Ru atoms for Ni atoms in the 4c positions, and the generation of donor defects in the form of vacancies in the Sn (4b) positions. The calculated electronic structure of HfNi{sub 1?x}Ru{sub x}Sn is consistent with the experiment. The results obtained are discussed within the Shklovsky-Efros model for a heavily doped and compensated semiconductor.

  6. 28 IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, VOL. 1, NO. 1, MARCH 2007 Feedback Analysis and Design of RF Power Links for

    E-Print Network [OSTI]

    Sarpeshkar, Rahul

    structure of an inductive power link system for an example implant. An RF power amplifier drives a primary Analysis and Design of RF Power Links for Low-Power Bionic Systems Michael W. Baker, Student Member, IEEE for analyzing and designing RF power links for transcutaneous bionic systems, i.e., between an external RF coil

  7. Am phases in the matrix of a U-Pu-Zr alloy with Np, Am, and rare-earth elements

    SciTech Connect (OSTI)

    Dawn E Janney; J. Rory Kennedy; James W. Madden; Thomas P. O'Holleran

    2015-01-01T23:59:59.000Z

    Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ?-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and ?-(U, Np, Pu, Am)Zr2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ?-(U, Np, Pu, Am) is higher than that in ?-(U, Pu) and the Zr content in ?-(U, Np, Pu, Am)Zr2 is lower than that in ?-UZr2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ?-(U, Np, Pu, Am) bracketed by zones of ?-(U, Np, Pu, Am)Zr2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ?-(U, Np, Pu, Am) and ?-(U, Np, Pu, Am)Zr2. Each of these domains is a few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.

  8. Diffusional Interaction between U – 10wt.% Zr and Fe at 903K, 923K and 953K

    SciTech Connect (OSTI)

    K Y. Park; K. Huang; A. Ewh; Y.H. Sohn; B. H. Sencer; J. R. Kennedy

    2015-01-01T23:59:59.000Z

    U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 903, 923 and 953K for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, alpha-U, betha-U, Zr-precipitates, ?, e and ? were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of ?, e and ?-phases. The ?, e and ?-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)2, and I4/mcm(140) U3(Zr,Fe), respectively.

  9. Composition-Morphology-Property Relations For Giant Magnetoresistance Multilayers Grown By RF Diode Sputtering

    E-Print Network [OSTI]

    Wadley, Haydn

    University of Virginia, Charlottesville, VA 22903 D. Brownell Nonvolatile Electronics, Inc. Eden Prairie, MN, Inc. (Eden Prairie, MN) using a Randex Model 2400-6J RF diode system. Briefly, the diameter

  10. High gain proportional rf control stability at TESLA cavities Elmar Vogel

    E-Print Network [OSTI]

    High gain proportional rf control stability at TESLA cavities Elmar Vogel Deutsches Elektronen) based on TESLA technology. Additional control loops improve the field regulation by treating repetitive loops is desirable for the strong suppression of nonpredictive and nonrepetitive disturbances. TESLA

  11. Thesis for the Degree of Licentiate of Engineering CTH-RF-190 Development and Investigation of

    E-Print Network [OSTI]

    Haviland, David

    Thesis for the Degree of Licentiate of Engineering CTH-RF-190 Development and Investigation (ADS), Feynman-alpha formulae, source modulation method, point kinetics #12;#12;This licentiate thesis

  12. The Design and Development of a Hybrid RF/Laser Radar System for Measuring Changes in

    E-Print Network [OSTI]

    Kansas, University of

    transmit power and higher PRF. RF pulse compression is used to improve system performance further. Receiver compression. Compared to laser radars like GLAS and MOLA, this sensor requires a lower peak transmit power Compression .......................................................... 14 2.6 Coherent Integration

  13. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources 

    E-Print Network [OSTI]

    Kurpad, Krishna Nagaraj

    2005-11-01T23:59:59.000Z

    The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the ...

  14. Study of RF Plasma Technology Applied to Air-Breathing Electric Propulsion

    E-Print Network [OSTI]

    Shyy, Wei

    Foster, thank you for being so encouraging, for listening to and understanding the woes of RF plasma research, and for being so friendly at conferences and in the hallways. Professor Longmier, welcome

  15. High-power rf-pulsed modulators for the Los Alamos free-electron laser

    SciTech Connect (OSTI)

    Johnson, W.J.D.; Lynch, M.T.; Tallerico, P.J.; Keffeler, D.R.; Hornkohl, J.O.

    1987-09-01T23:59:59.000Z

    In the rf-driven free-electron laser (FEL) at the Los Alamos National Laboratory, there are two pulsed-power rf modulators as sources for two tandem, side-coupled 20-MeV linear accelerators. The rf power used to control the cavity fields is supplied by two 5.5-MW modulating anode klystrons operating at a center frequency of 1300.2 MHz. The modulation of the 125 kV klystron is achieved by using a triode switch tube that provides a pulse width up to 300 ..mu..s and a pulse repetition rate up to 10 Hz. This paper describes the present configuration of these two duplicate systems and presents plans for meeting the requirements of future rf FEL experiments at Los Alamos. 12 refs., 5 figs.

  16. PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORY Photonic RF Waveform Synthesis,

    E-Print Network [OSTI]

    Purdue University

    PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER COMMUNICATIONS LABORATORY Photonic RF Waveform, Shijun Xiao Funding from ARO, DARPA, and NSF #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL FIBER performance (spectral engineering, dispersion compensation) #12;PURDUE UNIVERSITY ULTRAFAST OPTICS & OPTICAL

  17. Design of a high quality factor spiral inductors in RF MCM-D

    E-Print Network [OSTI]

    Peters, Joshua, 1981-

    2004-01-01T23:59:59.000Z

    This thesis studies the design and fabrication of spiral inductors for use in Radio Frequency (RF) applications. A design methodology is developed to search an inductor design space efficiently using existing simulation ...

  18. A New First-Principles Calculation of Field-Dependent RF Surface Impedance of BCS Superconductor

    SciTech Connect (OSTI)

    Xiao, Binping [Brookhaven National Laboratory, Upton, New York (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01T23:59:59.000Z

    There is a need to understand the intrinsic limit of radiofrequency (RF) surface impedance that determines the performance of superconducting RF cavities in particle accelerators. Here we present a field-dependent derivation of Mattis-Bardeen theory of the RF surface impedance of BCS superconductors based on the shifted density of states resulting from coherently moving Cooper pairs. Our theoretical prediction of the effective BCS RF surface resistance (Rs) of niobium as a function of peak surface magnetic field amplitude agrees well with recently reported record low loss resonant cavity measurements from JLab and FNAL with carefully, yet differently, prepared niobium material. The surprising reduction in resistance with increasing field is explained to be an intrinsic effect.

  19. Detection technique and front-end RF tunable filter for cognitive radio systems

    E-Print Network [OSTI]

    Park, Sanghoon

    2010-01-01T23:59:59.000Z

    dual-mode WiMAX/WLAN direct- conversion receiver,” in Proc.Hamilton, “Aspects of direct conversion receiver design,” inand M. Ismail, “A direct conversion WiMAX RF receiver front-

  20. Tunable Substrate Integrated Waveguide Filters Implemented with PIN Diodes and RF MEMS Switches 

    E-Print Network [OSTI]

    Armendariz, Marcelino

    2012-02-14T23:59:59.000Z

    This thesis presents the first fully tunable substrate integrated waveguide (SIW) filter implemented with PIN diodes and RF MEMS switches. The methodology for tuning SIW filters is explained in detail and is used to create three separate designs...

  1. Tunable Substrate Integrated Waveguide Filters Implemented with PIN Diodes and RF MEMS Switches

    E-Print Network [OSTI]

    Armendariz, Marcelino

    2012-02-14T23:59:59.000Z

    This thesis presents the first fully tunable substrate integrated waveguide (SIW) filter implemented with PIN diodes and RF MEMS switches. The methodology for tuning SIW filters is explained in detail and is used to create three separate designs...

  2. Processing of U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys by sintering process

    SciTech Connect (OSTI)

    Dos Santos, A. M. M.; Ferraz, W. B.; Lameiras, F. S.; Mazzeu, T. D. O. [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN-CNEN, Av. Presidente Antionio Carlos 6.627, 31270-901 Belo Horizonte, MG (Brazil)

    2012-07-01T23:59:59.000Z

    To minimize the risk of nuclear proliferation, there is worldwide interest in reducing fuel enrichment of research and test reactors. To achieve this objective while still guaranteeing criticality and cycle length requirements, there is need of developing high density uranium metallic fuels. Alloying elements such as Zr, Nb and Mo are added to uranium to improve fuel performance in reactors. In this context, the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) is developing the U-2.5Zr-7.5Nb and U-3Zr-9Nb (weight %) alloys by the innovative process of sintering that utilizes raw materials in the form of powders. The powders were pressed at 400 MPa and then sintered under a vacuum of about 1x10{sup -4} Torr at temperatures ranging from 1050 deg. to 1500 deg.C. The densities of the alloys were measured geometrically and by hydrostatic method and the phases identified by X ray diffraction (XRD). The microstructures of the pellets were observed by scanning electron microscopy (SEM) and the alloying elements were analyzed by energy dispersive X-ray spectroscopy (EDS). The results obtained showed the fuel density to slightly increase with the sintering temperature. The highest density achieved was approximately 80% of theoretical density. It was observed in the pellets a superficial oxide layer formed during the sintering process. (authors)

  3. Automatic Pole and Q-Value Extraction for RF Structures

    SciTech Connect (OSTI)

    C. Potratz, H.-W. Glock, U. van Rienen, F. Marhauser

    2011-09-01T23:59:59.000Z

    The experimental characterization of RF structures like accelerating cavities often demands for measuring resonant frequencies of Eigenmodes and corresponding (loaded) Q-values over a wide spectral range. A common procedure to determine the Q-values is the -3dB method, which works well for isolated poles, but may not be applicable directly in case of multiple poles residing in close proximity (e.g. for adjacent transverse modes differing by polarization). Although alternative methods may be used in such cases, this often comes at the expense of inherent systematic errors. We have developed an automation algorithm, which not only speeds up the measurement time significantly, but is also able to extract Eigenfrequencies and Q-values both for well isolated and overlapping poles. At the same time the measurement accuracy may be improved as a major benefit. To utilize this procedure merely complex scattering parameters have to be recorded for the spectral range of interest. In this paper we present the proposed algorithm applied to experimental data recorded for superconducting higher-order-mode damped multi-cell cavities as an application of high importance.

  4. Operation of the superconducting RF photo gun at ELBE

    E-Print Network [OSTI]

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, Ch; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2012-01-01T23:59:59.000Z

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 ?A average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  5. Operation of the superconducting RF photo gun at ELBE

    E-Print Network [OSTI]

    Teichert, J; Buettig, H; Janssen, D; Justus, M; Lehnert, U; Michel, P; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R; Kamps, T; Rudolph, J; Schenk, M; Klemz, G; Will, I

    2011-01-01T23:59:59.000Z

    As the first superconducting RF photo-injector (SRF gun) in practical operation, the SRF gun has been successfully connected to the superconducting linac ELBE at Forschungzentrum Dresden-Rossendorf. The injection with this new gun will improve the beam quality for the users of the radiation source. The SRF gun contains a 3½ cell superconducting accelerating cavity with a frequency of 1.3 GHz. The design is for use of normal conducting photocathodes. At present, caesium telluride photocathodes are applied which are illuminated by an ultraviolet laser beam. The kinetic energy of the produced electron beam is 3 MeV which belongs to a peak electric field of 16 MV/m in the cavity. The maximum bunch charge which is obtained and measured in a Faraday cup is about 400 pC (20 µA average current at a repetition rate of 50 kHz). The SRF gun injector is connected to the ELBE accelerator via a dogleg with two 45° deflection magnets. This connection beam line was commissioned in January 2010. A first beam injection into...

  6. Important requirements for RF generators for Accelerator-Driven Transmutation Technologies (ADTT)

    SciTech Connect (OSTI)

    Lynch, M.T.; Tallerico, P.J.; Lawrence, G.P.

    1994-09-01T23:59:59.000Z

    All Accelerator-Driven Transmutation applications require very large amounts of RF Power. For example, one version of a Plutonium burning system requires an 800-MeV, 80-mA, proton accelerator running at 100% duty factor. This accelerator requires approximately 110-MW of continuous RF power if one assumes only 10% reserve power for control of the accelerator fields. In fact, to minimize beam spill, the RF controls may need as much as 15 to 20% of reserve power. In addition, unlike an electron accelerator in which the beam is relativistic, a failed RF station can disturb the synchronism of the beam, possibly shutting down the entire accelerator. These issues and more lead to a set of requirements for the RF generators which are stringent, and in some cases, conflicting. In this paper, we will describe the issues and requirements, and outline a plan for RF generator development to meet the needs of the Accelerator-Driven Transmutation Technologies. The key issues which will be discussed include: operating efficiency, operating linearity, effect on the input power grid, bandwidth, gain, reliability, operating voltage, and operating current.

  7. Phase Noise of the Radio Frequency (RF) Beatnote Generated by a Dual-Frequency VECSEL

    E-Print Network [OSTI]

    Syamsundar De; Abdelkrim El Amili; Ihsan Fsaifes; Grégoire Pillet; Ghaya Baili; Fabienne Goldfarb; Mehdi Alouini; Isabelle Sagnes; Fabien Bretenaker

    2013-11-13T23:59:59.000Z

    We analyze, both theoretically and experimentally, the phase noise of the radio frequency (RF) beatnote generated by optical mixing of two orthogonally polarized modes in an optically pumped dual-frequency Vertical External Cavity Surface Emitting Laser (VECSEL). The characteristics of the RF phase noise within the frequency range of 10 kHz - 50 MHz are investigated for three different nonlinear coupling strengths between the two lasing modes. In the theoretical model, we consider two different physical mechanisms responsible for the RF phase noise. In the low frequency domain (typically below 500 kHz), the dominant contribution to the RF phase noise is shown to come from the thermal fluctuations of the semicondutor active medium induced by pump intensity fluctuations. However, in the higher frequency domain (typically above 500 kHz), the main source of RF phase noise is shown to be the pump intensity fluctuations which are transfered to the intensity noises of the two lasing modes and then to the phase noise via the large Henry factor of the semiconductor gain medium. For this latter mechanism, the nonlinear coupling strength between the two lasing modes is shown to play an important role in the value of the RF phase noise. All experimental results are shown to be in good agreement with theory.

  8. Phase formation in ZrFe multilayers: Effect of irradiation A. T. Motta

    E-Print Network [OSTI]

    Motta, Arthur T.

    of the wavelength, indicating a process controlled by atomic transport. Amorphization was also achieved by 900 ke disappears first, indicating that amorphization takes place in the Zr layer by atomic transport of Fe from, likely because there was competition with formation of other phases. The reaction kinetics were

  9. Thermoluminescence of ZrSiO4 (zircon): A new dating method?

    E-Print Network [OSTI]

    Donoghue, Joseph

    Thermoluminescence of ZrSiO4 (zircon): A new dating method? H.J. van Es a , D.I. Vainshtein a , A (TL) dating of sediments from the Quaternary. TL of zircon results predominantly from internal0168-583X(02)00627-4 #12;Heavily damaged grains significantly reduce the thermoluminescence (TL) light

  10. ccsd00004518, Precipitation kinetics of Al 3 Zr and Al 3 Sc in

    E-Print Network [OSTI]

    , kinetics, aluminum alloys, cluster dynamics PACS: 64.60.Cn, 64.60.-i, 64.70.Kb, 64.75.+g 1 Introduction Transition elements are added to aluminum alloys so as to obtain small ordered precipitates and by this wayccsd­00004518, version 2 ­ 21 Mar 2005 Precipitation kinetics of Al 3 Zr and Al 3 Sc in aluminum

  11. Phase Stability and Thermodynamic Assessment of the Np-Zr system 

    E-Print Network [OSTI]

    Bajaj, Saurabh

    2012-02-14T23:59:59.000Z

    / clustering trends of the bcc phase, a thermodynamic study is performed using the CALPHAD method. The calculated Np-Zr phase diagram is consistent with two sets of data: formation enthalpies of the bcc phase that are calculated with ab initio KKR...

  12. Deformation Microstructures and Creep Mechanisms in Advanced ZR-Based Cladding Under Biazal Loading

    SciTech Connect (OSTI)

    K. Linga (KL) Murty

    2008-08-11T23:59:59.000Z

    Investigate creep behavior of Zr-based cladding tubes with attention to basic creep mechanisms and transitions in them at low stresses and/or temperatures and study the dislocation microstructures of deformed samples for correlation with the underlying micromechanism of creep

  13. Complexity of shear localization in a Zr-based bulk metallic glass

    E-Print Network [OSTI]

    University of Aeronautics and Astronautics, Beijing 100191, China The compressive behaviour of a Zr. A significant advance occurred when compositions and copper mold casting method allowing for bulk material the consequence of) macroscopic shear banding remains unclear. It is therefore important to carry out in situ

  14. Complexity of shear localization in a Zr-based bulk metallic glass

    E-Print Network [OSTI]

    University of Aeronautics and Astronautics, Beijing 100191, China The compressive behaviour of a Zr. A significant advance occurred when compositions and copper mold casting method allowing for bulk material unclear. It is therefore important to carry out in situ observations of plastic deformation processes

  15. Stress-corrosion fatiguecrack growth in a Zr-based bulk amorphous metal

    E-Print Network [OSTI]

    Ritchie, Robert

    Stress-corrosion fatigue­crack growth in a Zr-based bulk amorphous metal V. Schroeder 1 , R metallic glass; Amorphous metal; Fatigue; Stress corrosion; Crack growth 1. Introduction In recent years­crack growth resistance [1­5], its corresponding properties in the presence of a corrosive environment have

  16. Effect of Niobium on the Defect Chemistry and Oxidation Kinetics of Tetragonal ZrO2

    E-Print Network [OSTI]

    Yildiz, Bilge

    Effect of Niobium on the Defect Chemistry and Oxidation Kinetics of Tetragonal ZrO2 Uuganbayar, Massachusetts 02139, United States ABSTRACT: Zirconium-niobium alloys are currently proposed for applications the effect of an extrinsic defect, niobium (Nb) dopant, on the defect equilibria and charge transfer

  17. Chemical Synthesis of Pure and Gd-doped CaZrO3 Powders

    E-Print Network [OSTI]

    Tas, A. Cuneyt

    chemical synthesis techniques: (i) self-propagating combustion synthesis, and (ii) precipitation potential use as a high-temperature thermistor material.8 The electrical response of calcium zirconate (preChemical Synthesis of Pure and Gd-doped CaZrO3 Powders I. Erkin Gonenli a and A. CuÃ? neyt Tas b

  18. Phase Stability and Thermodynamic Assessment of the Np-Zr system

    E-Print Network [OSTI]

    Bajaj, Saurabh

    2012-02-14T23:59:59.000Z

    of minor actinides and fission products on phase stability. Within this framework, we present a study on phase equilibria in the binary Np-Zr alloy system on which little work has been published. To resolve the contradictory reports on the ordering...

  19. The integration of Human Factors (HF) in the SAR process training course text

    SciTech Connect (OSTI)

    Ryan, T.G.

    1995-03-01T23:59:59.000Z

    This text provides the technical basis for a two-day course on human factors (HF), as applied to the Safety Analysis Report (SAR) process. The overall objective of this text and course is to: provide the participant with a working knowledge of human factors-related requirements, suggestions for doing a human safety analysis applying a graded approach, and an ability to demonstrate using the results of the human safety analysis, that human factors elements as defined by DOE (human factors engineering, procedures, training, oversight, staffing, qualifications), can support wherever necessary, nuclear safety commitments in the SAR. More specifically, the objectives of the text and course are: (1) To provide the SAR preparer with general guidelines for doing HE within the context of a graded approach for the SAR; (2) To sensitize DOE facility managers and staff, safety analysts and SAR preparers, independent reviewers, and DOE reviewers and regulators, to DOE Order 5480.23 requirements for HE in the SAR; (3) To provide managers, analysts, reviewers and regulators with a working knowledge of HE concepts and techniques within the context of a graded approach for the SAR, and (4) To provide SAR managers and DOE reviewers and regulators with general guidelines for monitoring and coordinating the work of preparers of HE inputs throughout the SAR process, and for making decisions regarding the safety relevance of HE inputs to the SAR. As a ready reference for implementing the human factors requirements of DOE Order 5480.22 and DOE Standard 3009-94, this course text and accompanying two-day course are intended for all persons who are involved in the SAR.

  20. RF Design and Operating Results for a New 201.25 MHz RF Power Amplifier for LANSCE

    SciTech Connect (OSTI)

    Lyles, John T. [Los Alamos National Laboratory; Baca, David M. [Los Alamos National Laboratory; Bratton, Ray E. [Los Alamos National Laboratory; Brennan, Nicholas W. [Los Alamos National Laboratory; Bultman, Nathan K. [Los Alamos National Laboratory; Chen, Zukun [Los Alamos National Laboratory; Davis, Jerry L. [Los Alamos National Laboratory; Naranjo, Angela C. [Los Alamos National Laboratory; Rees, Daniel E. [Los Alamos National Laboratory; Sandoval, Gilbert M. Jr. [Los Alamos National Laboratory; Summers, Richard D. [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    A prototype VHF RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, and tested. The cavity amplifier has met the goals of generating 2.5 MW peak and 260 kW of average power, at an elevation of 2.1 km. It was designed to use a Thales TH628 Diacrode{sup R}, a state-of-art tetrode power tube that is double-ended, providing roughly twice the power of a conventional tetrode. The amplifier is designed with tunable input and output transmission line cavity circuits, a grid decoupling circuit, an adjustable output coupler, TE mode suppressors, blocking, bypassing and decoupling capacitors, and a cooling system. The tube is connected in a full wavelength output circuit, with the lower main tuner situated 3/4{lambda} from the central electron beam region in the tube and the upper slave tuner 1/4{lambda} from the same point. We summarize the design processes and features of the FPA along with significant test results. A pair of production amplifiers are planned to be power-combined and installed at the LANSCE DTL to return operation to full beam duty factor.

  1. Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

    SciTech Connect (OSTI)

    Adibi, Sara [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore); Branicio, Paulo S., E-mail: branicio@ihpc.a-star.edu.sg; Zhang, Yong-Wei [Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore); Joshi, Shailendra P., E-mail: Shailendra@nus.edu.sg [Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)

    2014-07-28T23:59:59.000Z

    Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15?nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5?nm for Cu{sub 36}Zr{sub 64} and 3?nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54?GPa/1.29?GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57?GPa /1.58?GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MG will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.

  2. RF properties of periodic accelerating structures for linear colliders

    SciTech Connect (OSTI)

    Wang, J.W.

    1989-07-01T23:59:59.000Z

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

  3. Experimental Studies of Light Emission Phenomena in Superconducting RF Cavitites

    SciTech Connect (OSTI)

    Anthony, P.L.; /SLAC; Delayen, J.R.; /Jefferson Lab; Fryberger, D.; /SLAC; Goree, W.S.; Mammosser, J.; /Jefferson Lab /SNS Project, Oak Ridge; Szalata, Z.M.; II, J.G.Weisend /SLAC

    2009-08-04T23:59:59.000Z

    Experimental studies of light emission phenomena in superconducting RF cavities, which we categorize under the general heading of cavity lights, are described. The cavity lights data, which were obtained using a small CCD video camera, were collected in a series of nine experimental runs ranging from {approx} 1/2 to {approx} 2 h in duration. The video data were recorded on a standard VHS tape. As the runs progressed, additional instrumentation was added. For the last three runs a LabVIEW controlled data acquisition system was included. These runs furnish evidence for several, possibly related, light emission phenomena. The most intriguing of these is what appear to be small luminous objects {le} 1.5 mm in size, freely moving about in the vacuum space, generally without wall contact, as verified by reflections of the tracks in the cavity walls. In addition, on a number of occasions, these objects were observed to bounce off of the cavity walls. The wall-bounce aspect of most of these events was clearly confirmed by pre-bounce and post-bounce reflections concurrent with the tracks. In one of the later runs, a mode of behavior was observed that was qualitatively different from anything observed in the earlier runs. Perhaps the most perplexing aspect of this new mode was the observation of as many as seven luminous objects arrayed in what might be described as a macromolecular formation, coherently moving about in the interior of the cavity for extended periods of time, evidently without any wall contact. It is suggested that these mobile luminous objects are without explanation within the realm of established physics. Some remarks about more exotic theoretical possibilities are made, and future plans are discussed.

  4. Repetitive Ultra-low Stress Induced Nanocrystallization in Amorphous Cu?Zr?Al Alloy Evidenced by in situ Nanoindentation

    E-Print Network [OSTI]

    Liu, Y.; Jian, J.; Lee, J. H.; Wang, C.; Cao, Q. P.; Gutierrez, C.; Wang, H.; Jiang, J. Z.; Zhang, X.

    2014-05-12T23:59:59.000Z

    sputtering system (DCMS, JZCK-400) by using a crystalline Cu45Zr48Al7 target. The composition of the films examined by electron-dispersive X-ray spectroscopy in a field-emission scanning electron micro- scope (FE-SEM, Hitachi S-4800) was Cu44Zr44Al12... C, Li C, Inoue A, Haas V. Deformation behavior of Zr- based bulk nanocrystalline amorphous alloys. Phys Rev B. 2000;61:R3761–R3763. [24] Chen M, Inoue A, Zhang W, Sakurai T. Extraordinary plasticity of ductile bulk metallic glasses. Phys Rev Lett...

  5. Thickness independent reduced forming voltage in oxygen engineered HfO{sub 2} based resistive switching memories

    SciTech Connect (OSTI)

    Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Komissinskiy, P.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-08-18T23:59:59.000Z

    The conducting filament forming voltage of stoichiometric hafnium oxide based resistive switching layers increases linearly with layer thickness. Using strongly reduced oxygen deficient hafnium oxide thin films grown on polycrystalline TiN/Si(001) substrates, the thickness dependence of the forming voltage is strongly suppressed. Instead, an almost constant forming voltage of about 3?V is observed up to 200?nm layer thickness. This effect suggests that filament formation and switching occurs for all samples in an oxidized HfO{sub 2} surface layer of a few nanometer thickness while the highly oxygen deficient thin film itself merely serves as a oxygen vacancy reservoir.

  6. Controlled oxygen vacancy induced p-type conductivity in HfO{sub 2-x} thin films

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Mueller, Mathis M.; Kleebe, Hans-Joachim; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, 15236 Frankfurt/Oder (Germany)

    2011-09-12T23:59:59.000Z

    We have synthesized highly oxygen deficient HfO{sub 2-x} thin films by controlled oxygen engineering using reactive molecular beam epitaxy. Above a threshold value of oxygen vacancies, p-type conductivity sets in with up to 6 times 10{sup 21} charge carriers per cm{sup 3}. At the same time, the band-gap is reduced continuously by more than 1 eV. We suggest an oxygen vacancy induced p-type defect band as origin of the observed behavior.

  7. Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

    2012-12-01T23:59:59.000Z

    We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

  8. Energy band alignment of atomic layer deposited HfO{sub 2} on epitaxial (110)Ge grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-04T23:59:59.000Z

    The band alignment properties of atomic layer HfO{sub 2} film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO{sub 2} film. The measured valence band offset value of HfO{sub 2} relative to (110)Ge was 2.28 {+-} 0.05 eV. The extracted conduction band offset value was 2.66 {+-} 0.1 eV using the bandgaps of HfO{sub 2} of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO{sub 2}/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices.

  9. Searches for HCl and HF in comets 103P/Hartley 2 and C/2009 P1 (Garradd) with the Herschel space observatory

    E-Print Network [OSTI]

    Bockelée-Morvan, D; Crovisier, J; Lis, D C; Hartogh, P; Moreno, R; de Val-Borro, M; Blake, G A; Szutowicz, S; Boissier, J; Cernicharo, J; Charnley, S B; Combi, M; Cordiner, M A; de Graauw, T; Encrenaz, P; Kidger, M; Küppers, M; Milam, S N; Müller, H S P; Phillips, T G; Rengel, M

    2014-01-01T23:59:59.000Z

    HCl and HF are expected to be the main reservoirs of fluorine and chlorine wherever hydrogen is predominantly molecular. They are found to be strongly depleted in dense molecular clouds, suggesting freeze-out onto grains in such cold environments. We can then expect that HCl and HF were also the major carriers of Cl and F in the gas and icy phases of the outer solar nebula, and were incorporated into comets. We aimed to measure the HCl and HF abundances in cometary ices as they can provide insights on the halogen chemistry in the early solar nebula. We searched for the J(1-0) lines of HCl and HF at 626 and 1232 GHz, respectively, using the HIFI instrument on board the Herschel Space Observatory. HCl was searched for in comets 103P/Hartley 2 and C/2009 P1 (Garradd), whereas observations of HF were conducted in comet C/2009 P1. In addition, observations of H$_2$O and H$_2^{18}$O lines were performed in C/2009 P1 to measure the H$_2$O production rate. Three lines of CH$_3$OH were serendipitously observed in the ...

  10. Simulation of RF Cavity Dark Current In Presence of Helical Magnetic Field

    SciTech Connect (OSTI)

    Romanov, Gennady; Kashikhin, Vladimir; /Fermilab

    2012-05-01T23:59:59.000Z

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  11. Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field

    SciTech Connect (OSTI)

    Romanov, Gennady; Kashikhin, Vladimir; /Unlisted

    2010-09-01T23:59:59.000Z

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  12. Stabilizing effect of a double-harmonic RF system in the CERN PS

    SciTech Connect (OSTI)

    Bhat, C.; /Fermilab; Caspers, F.; Damerau, H.; Hancock, S.; Mahner, E.; Zimmermann, F.; /CERN

    2009-04-01T23:59:59.000Z

    Motivated by the discussions on scenarios for LHC upgrades, beam studies on the stability of flat bunches in a double-harmonic RF system have been conducted in the CERN Proton Synchrotron (PS). Injecting nearly nominal LHC beam intensity per cycle, 18 bunches are accelerated on harmonic h = 21 to 26GeV with the 10MHz RF system. On the flat-top, all bunches are then transformed to flat bunches by adiabatically adding RF voltage at h = 42 from a 20 MHz cavity in anti-phase to the h = 21 system. The voltage ratio V (h42)/V (h21) of about 0.5 was set according to simulations. For the next 140 ms, longitudinal profiles show stable bunches in the double-harmonic RF bucket until extraction. Without the second harmonic component, coupled-bunch oscillations are observed. The flatness of the bunches along the batch is analyzed as a measure of the relative phase error between the RF systems due to beam loading. The results of beam dynamics simulations and their comparison with the measured data are presented.

  13. Multipole and field uniformity tailoring of a 750 MHz rf dipole

    SciTech Connect (OSTI)

    Delayen, Jean R. [JLAB, Old Dominion University; Castillo, Alejandro [JLAB, Old Dominion University

    2014-12-01T23:59:59.000Z

    In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependency is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations.

  14. Defects and Minor Phases in O+ and Zr+ Ion Co-implanted SrTiO3...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    recovery at the surface with little recovery occurring at the damage peak, where a modest recovery is observed upon further annealing at 1423 K. Some of the implanted Zr...

  15. Ab initio investigation of phase stability of Y2Ti2O7 and Y2Zr2O7...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to the defect-cotunnite state under high pressure. Citation: Xiao HY, F Gao, and WJ Weber.2009."Ab initio investigation of phase stability of Y2Ti2O7 and Y2Zr2O7 under high...

  16. Pressure Induced Structural Transformation in Gd2Ti2O7 and Gd2Zr2O7...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in determining the pressure induced phase transformation. Citation: Xiao HY, and WJ Weber.2011."Pressure Induced Structural Transformation in Gd2Ti2O7 and Gd2Zr2O7."Journal of...

  17. Charge-trapping characteristics of fluorinated thin ZrO{sub 2} film for nonvolatile memory applications

    SciTech Connect (OSTI)

    Huang, X. D., E-mail: eexdhuang@gmail.com, E-mail: laip@eee.hku.hk [Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 210096 (China); Shi, R. P.; Lai, P. T., E-mail: eexdhuang@gmail.com, E-mail: laip@eee.hku.hk [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2014-04-21T23:59:59.000Z

    The effects of fluorine treatment on the charge-trapping characteristics of thin ZrO{sub 2} film are investigated by physical and electrical characterization techniques. The formation of silicate interlayer at the ZrO{sub 2}/SiO{sub 2} interface is effectively suppressed by fluorine passivation. However, excessive fluorine diffusion into the Si substrate deteriorates the quality of the SiO{sub 2}/Si interface. Compared with the ZrO{sub 2}-based memory devices with no or excessive fluorine treatment, the one with suitable fluorine-treatment time shows higher operating speed and better retention due to less resistance of built-in electric field (formed by trapped electrons) against electron injection from the substrate and smaller trap-assisted tunneling leakage, resulting from improved ZrO{sub 2}/SiO{sub 2} and SiO{sub 2}/Si interfaces.

  18. Hardness variation and cyclic crystalline-amorphous phase transformation in CuZr alloy during ball milling

    E-Print Network [OSTI]

    Schoen, David Taylor

    2005-01-01T23:59:59.000Z

    The hardness and percent crystallinity of Cu33Zr67 powder samples are measured through several cycles of a cyclic phase transformation during ball milling. Each are found to cycle with a period of approximately 320 minutes. ...

  19. Electrochemical corrosion behavior of biomedical Ti22Nb and Ti22Nb6Zr alloys in saline medium

    E-Print Network [OSTI]

    Zheng, Yufeng

    Electrochemical corrosion behavior of biomedical Ti­22Nb and Ti­22Nb­6Zr alloys in saline medium B addition and potentiodynamic polarization on the microstructure and corrosion resistance of Ti­22Nb and Ti­22Nb­6Zr alloy samples.The corrosion tests were carried out in 0.9% NaCl at 37 8C and neutral p

  20. Proton diffusion pathways and rates in Y-doped BaZrO3 solid oxide electrolyte from quantum mechanics

    E-Print Network [OSTI]

    Goddard III, William A.

    Proton diffusion pathways and rates in Y-doped BaZrO3 solid oxide electrolyte from quantum barriers for intraoctahedral and interoctahedral proton transfers. We find activation energy Ea values of 0.48 and 0.49 eV for the intraoctahedral proton transfers on O­O edges 2.58 and 2.59 Å of ZrO6 and YO6

  1. Features of an intermetallic n-ZrNiSn semiconductor heavily doped with atoms of rare-earth metals

    SciTech Connect (OSTI)

    Romaka, V. A., E-mail: vromaka@polynet.lviv.ua [National Academy of Sciences of Ukraine, Ya. Pidstryhach Institute for Applied Problems of Mechanics and Mathematics (Ukraine); Fruchart, D.; Hlil, E. K. [CNRS, Institute Neel (France); Gladyshevskii, R. E. [Ivan Franko Lviv National University (Ukraine); Gignoux, D. [CNRS, Institute Neel (France); Romaka, V. V.; Kuzhel, B. S. [Ivan Franko Lviv National University (Ukraine); Krayjvskii, R. V. [Lvivska Politechnika National University (Ukraine)

    2010-03-15T23:59:59.000Z

    The crystal structure, density of electron states, electron transport, and magnetic characteristics of an intermetallic n-ZrNiSn semiconductor heavily doped with atoms of rare-earth metals (R) have been studied in the ranges of temperatures 1.5-400 K, concentrations of rare-earth metal 9.5 x 10{sup 19}-9.5 x 10{sup 21} cm{sup -3}, and magnetic fields H {<=} 15 T. The regions of existence of Zr{sub 1-x}R{sub x}NiSn solid solutions are determined, criteria for solubility of atoms of rare-earth metals in ZrNiSn and for the insulator-metal transition are formulated, and the nature of 'a priori doping' of ZrNiSn is determined as a result of redistribution of Zr and Ni atoms at the crystallographic sites of Zr. Correlation between the concentration of the R impurity, the amplitude of modulation of the bands of continuous energies, and the degree of occupation of potential wells of small-scale fluctuations with charge carriers is established. The results are discussed in the context of the Shklovskii-Efros model of a heavily doped and compensated semiconductor.

  2. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron

    E-Print Network [OSTI]

    Brian Chase; Ralph Pasquinelli; Ed Cullerton; Philip Varghese

    2014-11-21T23:59:59.000Z

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  3. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron

    E-Print Network [OSTI]

    Chase, Brian; Cullerton, Ed; Varghese, Philip

    2015-01-01T23:59:59.000Z

    The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.

  4. Commissioning the new high power rf system for the AGS with high intensity beam

    SciTech Connect (OSTI)

    Brennan, J.M.; Ciardullo, D.J.; Deng, D.P; Hayes, T.; Onillon, E.; Otis, A.; Sanders, R.T.; Zaltsman, A.

    1994-08-01T23:59:59.000Z

    A new high power rf system has been installed in the AGS in order to raise the beam loading limit to beyond 6 {times} 10{sup 13} protons per pulse. The old system was limited to 2.2 {times} 10{sup l3} ppp by: available real power, multi-loop instability, and transient beam loading during batch filling from the Booster. The key components of the new system are: new power amplifiers in the tunnel using the Thomson-CSF TH573 300kW tetrode, rf feedback around the power stage, and reduction of the 10 cavities` R/Q by 1.8 by additional gap capacitors. Commissioning of the new rf system with high intensity beam is described. The intensity goal for the 1994 running period is 4 {times} 10{sup 13} ppp. To date, 3.7 {times} 10{sup 13} ppp has been achieved.

  5. Final Technical Report- Back-gate Field Emission-based Cathode RF Electron Gun

    SciTech Connect (OSTI)

    McGuire, Gary; Martin, Allen; Noonan, John

    2010-10-30T23:59:59.000Z

    The objective was to complete the design of an electron gun which utilizes a radio frequency (RF) power source to apply a voltage to a field emission (FE) cathode, a so called cold cathode, in order to produce an electron beam. The concept of the RF electron gun was originally conceived at Argonne National Laboratory but never reduced to practice. The research allowed the completion of the design based upon the integration of the FE electron source. Compared to other electron guns, the RF gun is very compact, less than one third the size of other comparable guns, and produces a high energy (to several MeV), high quality, high power electron beam with a long focal length with high repetition rates. The resultant electron gun may be used in welding, materials processing, analytical equipment and waste treatment.

  6. Phase-resolved optical emission of dusty rf discharges: Experiment and simulation

    SciTech Connect (OSTI)

    Melzer, Andre; Huebner, Simon; Lewerentz, Lars; Schneider, Ralf [Institut fuer Physik, Ernst-Moritz-Arndt-Universiaet, D-17489 Greifswald (Germany); Matyash, Konstantin [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Ikkurthi, Ramana [Institute for Plasma Research, Bhat, Ghandinagar, Gujarat (India)

    2011-03-15T23:59:59.000Z

    The spectral emission of atoms in a dusty radio frequence (rf) discharge plasma in argon and helium has been measured with a gated ICCD camera. The spatially and temporally resolved emission/excitation of the argon and helium atoms during the rf cycle in the dusty discharge was compared to the dust-free case. In the bulk plasma above the dust cloud, the emission is clearly enhanced in the dusty discharge with respect to the pure discharge, whereas in the sheath the emission is reduced. In addition, the emission of a dusty argon plasma is studied via particle-particle particle-mesh (P{sup 3}M) simulations. The rf dynamics with a single dust particle trapped in the sheath was calculated. Like in the experiment the dust modifies the atomic emission. The spatiotemporal excitation pattern of the experiment is reproduced and a detailed understanding of the difference in excitation of the discharge with and without dust is presented.

  7. RF transmission line and drill/pipe string switching technology for down-hole telemetry

    DOE Patents [OSTI]

    Clark, David D. (Santa Fe, NM); Coates, Don M. (Santa Fe, NM)

    2007-08-14T23:59:59.000Z

    A modulated reflectance well telemetry apparatus having an electrically conductive pipe extending from above a surface to a point below the surface inside a casing. An electrical conductor is located at a position a distance from the electrically conductive pipe and extending from above the surface to a point below the surface. Modulated reflectance apparatus is located below the surface for modulating well data into a RF carrier transmitted from the surface and reflecting the modulated carrier back to the surface. A RF transceiver is located at the surface and is connected between the electrically conductive pipe and the electrical conductor for transmitting a RF signal that is confined between the electrically conductive well pipe and the electrical conductor to the modulated reflectance apparatus, and for receiving reflected data on the well from the modulated reflectance apparatus.

  8. Fluorohydrogenate Cluster Ions in the Gas Phase: Electrospray Ionization Mass Spectrometry of the [1-Ethyl-3-methylimidazolium+][F(HF)2.3–] Ionic Liquid

    SciTech Connect (OSTI)

    Gary S. Groenewold; James E. Delmore; Michael T. Benson; Tetsuya Tsuda; Rika Hagiwara

    2013-12-01T23:59:59.000Z

    Electrospray ionization of the fluorohydrogenate ionic liquid [1-ethyl-3-methylimidazolium][F(HF)2.3] ionic liquid was conducted to understand the nature of the anionic species as they exist in the gas phase. Abundant fluorohydrogenate clusters were produced; however, the dominant anion in the clusters was [FHF-], and not the fluoride-bound HF dimers or trimers that are seen in solution. Density functional theory (DFT) calculations suggest that HF molecules are bound to the clusters by about 30 kcal/mol. The DFT-calculated structures of the [FHF-]-bearing clusters show that the favored interactions of the anions are with the methynic and acetylenic hydrogen atoms on the imidazolium cation, forming planar structures similar to those observed in the solid state. A second series of abundant negative ions was also formed that contained [SiF5-] together with the imidazolium cation and the fluorohydrogenate anions that originate from reaction of the spray solution with silicate surfaces.

  9. Synthesis of bulk FeHfBO soft magnetic materials and its loss characterization at megahertz frequency

    SciTech Connect (OSTI)

    Zhou Yang; Kou Xiaoming; Warsi Muhammad, Asif; Lin Shuo; Harris, Brendan S.; Parsons, Paul E.; Xiao, John Q. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Mu Mingkai; Lee, Fred C. [Center for Power Electronics System, Virginia Polytechnic and State University, Blacksburg, Virginia 24060 (United States); Zhu Hao [Spectrum Magnetics LLC, Wilmington, Delaware 19804 (United States)

    2013-05-07T23:59:59.000Z

    Magnetic core materials with low loss, high saturation magnetization, large permeability, and operating frequency above 1 MHz are in high demands for the next generation of miniaturized power electronics. Amorphous FeHfB ribbons with thickness around 20 {mu}m have been fabricated through melt-spinning. Different heat treatments were performed on the FeHfB ribbons, and the relations among heat treatments, microstructure, and magnetic properties have been explored. Properties such as coercivity (H{sub c}) of 2.0 Oe and saturation magnetic flux density (B{sub S}) of 1.2 T have been achieved in samples with exchange coupling. The losses can be minimized by balancing the hysteretic and eddy current losses and can be further reduced with additional magnetic field annealing. At 5 MHz with peak magnetic flux density of 20 mT, the materials show core losses comparable to the best ferrites, but with higher permeability value of about 200 and superior saturation induction of more than 1 T.

  10. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    SciTech Connect (OSTI)

    Kalay, Ilkay

    2010-12-15T23:59:59.000Z

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental research on the behaviors of glass forming alloys. Further motivation arising from the application of this system as a basis for many BMGs and ACC materials; the Cu-Zr system warrants this attention and offers great potential for the development of new materials. However, the prediction and control of microstructural evolution during devitrification remains challenging because of the complex devitrification behavior of the Cu-Zr binary alloy which is arising from the competition of metastable and stable phases and diversity of crystal structures. This dissertation details a systematic fundamental investigation into the mechanisms and kinetics of the various crystallization transformation processes involved in the overall devitrification response of Cu-Zr and Cu-Zr-Al glasses. Various isothermal and nonisothermal treatments are employed, and the structural response is characterized using bulk X-ray and thermal analysis methods as well as nanoscale microscopic analysis methods, revealing structural and chemical details down to the atomic-scale. By carefully combining techniques such as differential scanning calorimetry (DSC), in-situ synchrotron high energy X-ray diffraction (HEXRD), and transmission electron microscopy (TEM) to quantify the characterization transformations, this research has uncovered numerous details concerning the atomistic mechanisms of crystallization and has provided much new understanding related to the dominant phases, the overall reaction sequences, and the rate-controlling mechanisms. As such this work represents a substantial step forward in understanding these transformations and provides a clear framework for further progress toward ultimate application of controlled devitrification processing for the production of new materials with remarkable properties.

  11. Permeability of CoNbZr amorphous thin films over a wide frequency range

    SciTech Connect (OSTI)

    Koyama, H.; Tsujimoto, H.; Shirae, K.

    1987-09-01T23:59:59.000Z

    CoNbZr amorphous films have attracted the attention of many researchers because of their high saturation magnetization, high permeability, low coercivity, and nearly zero magnetostriction. For these films to be used, one of the important magnetic properties is the behavior of the permeability over a wide frequency range. We have measured the permeability of a square-shaped magnetic film (13 mm x 55 mm) sputtered on a glass substrate from 1 MHz to 400 MHz using a stripline. Over 400 MHz, the permeability of the magnetic film was measured using a ring-shaped sample mounted in a coaxial fixture. The wall motion permeability of CoNbZr amorphous films decreases from 1 kHz to nearly zero at 1 MHz. The rotation permeability is constant to 100 MHz and ferromagnetic resonance is observed near 1 GHz.

  12. Influence of multiphonon excitations and transfer on the fusion of Ca+Zr

    E-Print Network [OSTI]

    H. Esbensen; A. M. Stefanini

    2014-04-16T23:59:59.000Z

    Fusion data for $^{48}$Ca+$^{90,96}$Zr are analyzed by coupled-channels calculations that are based on the M3Y+repulsion, double-folding potential. By applying a previously determined nuclear density of $^{48}$Ca, the neutron densities of the zirconium isotopes are adjusted to optimize the fit to the fusion data, whereas the proton densities are determined by electron scattering experiments. It is shown that the fusion data can be explained fairly well by including couplings to one- and two-phonon excitations of the reacting nuclei and to one- and two-nucleon transfer reactions but there is also some sensitivity to multiphonon excitations. The neutron skin thicknesses extracted for the two zirconium isotopes are consistent with anti-proton measurements. The densities of the zirconium isotopes are used together with the previously determined nuclear density of $^{40}$Ca to calculate the M3Y+repulsion potentials and predict the fusion cross sections of $^{40}$Ca+$^{90,96}$Zr. The predicted cross sections for $^{40}$Ca+$^{90}$Zr are in reasonable agreement with the data when the influence of multiphonon excitations and a modest transfer is considered. The prediction of the $^{40}$Ca+$^{96}$Zr fusion cross section, on the other hand, is poor and under-predicts the data by 30 to 40%. Although couplings to transfer channels with positive $Q$ values were expected to play an important role, they are not able to explain the data, primarily because the predicted Coulomb barrier is about 1.5 MeV too high. Possible reasons for this failure are discussed.

  13. Effect of RF Gradient upon the Performance of the Wisconsin SRF Electron Gun

    SciTech Connect (OSTI)

    Bosch, Robert [SRC U. Wisconsin-Madison; Legg, Robert A. [JLAB

    2013-12-01T23:59:59.000Z

    The performance of the Wisconsin 200-MHz SRF electron gun is simulated for several values of the RF gradient. Bunches with charge of 200 pC are modeled for the case where emittance compensation is completed during post-acceleration to 85 MeV in a TESLA module. We first perform simulations in which the initial bunch radius is optimal for the design gradient of 41 MV/m. We then optimize the radius as a function of RF gradient to improve the performance for low gradients.

  14. Method and apparatus for transferring and injecting rf energy from a generator to a resonant load

    DOE Patents [OSTI]

    Hoffert, William J. (Albuquerque, NM)

    1987-01-01T23:59:59.000Z

    Improved apparatus and method are provided for the coherent amplification and injection of radio-frequency (rf) energy into a load cavity using a plurality of amplifier tubes. A plurality of strip line cavities (30, 32, 34, 36, 40, 42, 44) are laterally joined to define a continuous closed cavity (48), with an amplifier tube (50, 52, 54, 56, 58, 60, 62, 64) mounted within each resonant strip cavity. Rf energy is injected into the continuous cavity (48) from a single input (70) for coherent coupling to all of the amplifier tubes for amplification and injection into the load cavity (76).

  15. Plasma sweeper to control the coupling of RF power to a magnetically confined plasma

    DOE Patents [OSTI]

    Motley, Robert W. (Princeton, NJ); Glanz, James (Lawrenceville, NJ)

    1985-01-01T23:59:59.000Z

    A device for coupling RF power (a plasma sweeper) from a phased waveguide array for introducing RF power to a plasma having a magnetic field associated therewith comprises at least one electrode positioned near the plasma and near the phased waveguide array; and a potential source coupled to the electrode for generating a static electric field at the electrode directed into the plasma and having a component substantially perpendicular to the plasma magnetic field such that a non-zero vector cross-product of the electric and magnetic fields exerts a force on the plasma causing the plasma to drift.

  16. Intelligent Low-level RF System by Non-destructive Beam Monitoring Device for Cyclotrons

    E-Print Network [OSTI]

    Malafeh, M S Sharifi Asadi; Afarideh, H; Chai, J S

    2015-01-01T23:59:59.000Z

    The project of a10MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work Intelligent Low Level Radio Frequency Circuit or ILLRF suitable for Most of the AVF cyclotron accelerators was designed by the beam monitoring device and narrow band tunable band-pass filter. In this design, for the RF phase detection does not need to signal processing by microcontroller

  17. Design of HOM coupler prototype for the APT superconducting RF cavities

    SciTech Connect (OSTI)

    Kuzminski, J. (Jozef); Spalek, G. (George); Bourque, R. F. (Robert F.)

    2001-01-01T23:59:59.000Z

    Beam dynamics calculations for the Accelerator Production of Tritium (APT) proton linac suggest that wakefields, which are excited during beam operation, would not lead to beam-breakup instabilities. However, in the superconducting (SC) radio-frequency (RF) cavities of the APT linac, higher-order modes (HOMs), whose frequencies are below the beam tube cut-off fiequency, can be sufficiently excited by the beam to add significantly to the heat load removed by the helium refrigerator. In this paper, we present a design of an HOM coupler for the APT RF cavities that will remove this power to a resistive load at room temperature.

  18. High power tests of dressed supconducting 1.3 GHz RF cavities

    SciTech Connect (OSTI)

    Hocker, A.; Harms, E.R.; Lunin, A.; Sukhanov, A.; /Fermilab

    2011-03-01T23:59:59.000Z

    A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted ('dressed') with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.

  19. A Novel Zr-1Nb Alloy and a New Look at Hydriding

    SciTech Connect (OSTI)

    Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

    2013-09-01T23:59:59.000Z

    A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys.

  20. Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a,

    E-Print Network [OSTI]

    Rosen, Matthew S

    Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a: Received 6 January 2012 Revised 14 March 2012 Available online 28 March 2012 Keywords: Nuclear singlet of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field

  1. Open-Thru de-embedding for Graphene RF devices Giancarlo Vincenzi, George Deligeorgis, Fabio Coccetti and Patrick Pons

    E-Print Network [OSTI]

    Boyer, Edmond

    Open-Thru de-embedding for Graphene RF devices Giancarlo Vincenzi, George Deligeorgis, Fabio, LAAS, F-31400 Toulouse, France Abstract--The performances of graphene RF devices rely heavily-embedding technique adapted to the needs of microwave graphene devices is presented. Two standards and only one step

  2. A Fiber-Optic-Based 1550-nm Laser Radar Altimeter with RF Pulse Compression Christopher Allen, Sivaprasad Gogineni

    E-Print Network [OSTI]

    Kansas, University of

    A Fiber-Optic-Based 1550-nm Laser Radar Altimeter with RF Pulse Compression Christopher Allen-the-shelf fiber-optic components and traditional RF and digital signal processing techniques to achieve fine erbium-doped fiber amplifiers (EDFAs) could be used to provide optical gain. The transmitted signal

  3. Development of a 1319 nm Laser Radar using Fiber-Optics and RF Pulse Compression: Receiver Characterization

    E-Print Network [OSTI]

    Kansas, University of

    Development of a 1319 nm Laser Radar using Fiber-Optics and RF Pulse Compression: Receiver and commercially available fiber-optic technologies. We use radio frequency (RF) pulse compression and digital commensurate with the desired range accuracy. With today's off-the-shelf fiber-optic components, multi

  4. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    DOE Patents [OSTI]

    Norem, James H.; Pellin, Michael J.

    2013-06-11T23:59:59.000Z

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  5. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN single crystal by sodium fluxScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  6. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    doped MOCVD grown GaN on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN singleScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  7. 2012 IEEE 30th VLSI Test Symposium (VTS) Towards a Fully Stand-Alone Analog/RF BIST: A

    E-Print Network [OSTI]

    Makris, Yiorgos

    -effective analog/RF BIST solution must rely on low-cost measurements obtained through on-chip sensors, along to achieve a fully stand-alone analog/RF BIST solution that can be used for low-cost production test as well in the low-cost measure- ment multi-dimensional space. To investigate this approach, we have designed

  8. Simulation results of an inductively-coupled rf plasma torch in two and three dimensions for producing a metal matrix composite for nuclear fuel cladding

    E-Print Network [OSTI]

    Holik III, Eddie Frank (Trey)

    2009-05-15T23:59:59.000Z

    I propose to develop a new method for the synthesis of metal matrix composites (MMC) using aerosol reactants in a radio frequency (RF) plasma torch. An inductivelycoupled RF plasma torch (ICPT) may potentially be designed to maintain laminar flow...

  9. 2004 URSI Meeting, 5-8 January 2004, at the University of Colorado, Boulder, Colorado, USA. Polyimide Planarization for RF-MEMS Switch on PCB

    E-Print Network [OSTI]

    De Flaviis, Franco

    Polyimide Planarization for RF-MEMS Switch on PCB Bahram Ghodsian, C. Jung, B. Cetiner and F. De Flaviis it maintains the high RF-performance of switches. The fabrication process uses polyimide to planerize

  10. Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

    1984-01-01T23:59:59.000Z

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  11. Ge MOS Characteristics with CVD HfO2 Gate Dielectrics and TaN Gate Electrode W. P. Bai*, N. Lu*, J. Liu*, A. Ramirez**, D. L. Kwong*, D. Wristers**, A. Ritenour#

    E-Print Network [OSTI]

    Ge MOS Characteristics with CVD HfO2 Gate Dielectrics and TaN Gate Electrode W. P. Bai*, N. Lu*, J, we report for the first time Ge MOS characteristics with ultra thin rapid thermal CVD HfO2 gate dielectrics and TaN gate electrode. Using the newly developed pre- gate cleaning and NH3-based Ge surface

  12. Synthesis and crystal structure of CuZrTiO{sub 5}-A new crystal structure type

    SciTech Connect (OSTI)

    Troitzsch, Ulrike [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Christy, Andrew G., E-mail: Andrew.Christy@anu.edu.a [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia); Willis, Anthony C. [Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia); Ellis, David J. [Research School of Earth Sciences, Australian National University, Canberra ACT 0200 (Australia)

    2010-03-15T23:59:59.000Z

    A new compound, CuZrTiO{sub 5}, was synthesized as strongly pleochroic green crystals from the oxides between 995 and 1010 deg. C, 1 atm. Its crystal structure was determined by single crystal XRD, resulting in R (F{sup 2}>2sigma(F{sup 2}))=0.032 and wR (all data)=0.079). CuZrTiO{sub 5} is orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A, V=352.35(4) A{sup 3}, Z=4. The structure is topologically similar to In{sub 2}TiO{sub 5} but differs in space group and cation coordination. CuZrTiO{sub 5} has relatively regular TiO{sub 6} polyhedra, but coordination is 7+1 for Zr, and 4+2 for Cu due to the Jahn-Teller effect. Ordering of the long Cu-O bonds causes reduction in symmetry relative to In{sub 2}TiO{sub 5}. Layers of Cu alternate with Ti+Zr on (001), giving rise to a distinct cleavage. Bond valence sums on Ti and Zr are far from ideal, which appears due to the limited ability of this structural topology to avoid close next-nearest neighbour distances. - Graphical abstract: The new compound CuZrTiO{sub 5} is orthorhombic (P2{sub 1}2{sub 1}2{sub 1}), with a=3.5871(3) A, b=6.6968(4) A, c=14.6679(9) A. The structure, determined with single crystal XRD, represents a new crystal structure type that is a slight distortion of that of In{sub 2}TiO{sub 5} but differs in space group and cation coordination.

  13. RE/ZrO{sub 2} (RE = Sm, Eu) composite oxide nano-materials: Synthesis and applications in photocatalysis

    SciTech Connect (OSTI)

    Du, Weimin, E-mail: duweimin75@gmail.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Zhu, Zhaoqiang [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhang, Xiaofen; Wang, Dacheng; Liu, Donghe [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Qian, Xuefeng [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Du, Jimin, E-mail: djm@aynu.edu.cn [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China)

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: • RE/ZrO{sub 2} (RE = Sm, Eu) nano-materials have been successfully synthesized. • Defect and electron structures determine the absorption properties on visible light. • Nano-sized Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} has good visible-light-responsive photocatalytic activities. • In the future, it can be used in wastewater treatment and environmental protection. - Abstract: Zirconia modified by Samarium/Europium, RE/ZrO{sub 2} (RE = Sm, Eu), composite oxide nano-materials have been successfully synthesized by improved sol–gel method. Characterization results show that X-ray diffraction (XRD) peaks of products gradually shift to the lower angle with the increase of rare earth which implies that the lattice distances of RE/ZrO{sub 2} nano-materials are gradually enlarged. Moreover, the molar ratios between zirconium and rare earth are consistent with the chemical formula and both of them are uniformly distributed in samples. Optical properties indicate that defect structures and electron configurations of RE/ZrO{sub 2} (RE = Sm, Eu) with single phase determine their absorption properties on visible light. Photocatalytic experiments indicate Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals have excellent visible-light-responsive photocatalytic activities on Methylene blue and Rhodamine B which results from the special defect structure, suitable electronic configuration, and larger specific surface area. It follows that Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals are new visible-light-responsive photocatalysts which can be applied in dye wastewater treatment and environmental protection in the future.

  14. Aspect Ratio Dependence of Bootstrap Current and RF Current Driving Efficiency

    E-Print Network [OSTI]

    Boyer, Edmond

    . Ashidaa a National Institute of advanced Industrial Science and Technology, Tsukuba, Japan, b Nihon University, Institute of Quantum Science, Tokyo, Japan, c Nihon University, College of Industrial Technology pinch (RFP) with the low aspect ratio of A = 2.0, then significantly reduces the rf-driven current

  15. PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC

    E-Print Network [OSTI]

    PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC S. Schreiber£ for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract The TESLA Test Facility Linac (TTFL) at DESY uses two modules with 8 TESLA superconducting accelerat- ing structures each to accelerate an electron

  16. FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC

    E-Print Network [OSTI]

    FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC S. Schreiber for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract During 1997 and 1998 a first accelerator module was tested successfully at the TESLA Test Facility Linac (TTFL) at DESY. Eight superconducting

  17. Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method Smail Bachir #1, the nonlinear Internal Model Control (IMC) method is introduced and applied to linearize high frequency Power to be controlled [8]. If the model is a perfect representation of the non linear system, the controller can

  18. IEEE ELECTRON DEVICE LETTERS, VOL. 24, NO. 4, APRIL 2003 227 RF MEMS Switches Fabricated on

    E-Print Network [OSTI]

    Cetiner, Bedri A.

    with superior performance over con- ventional semiconductor devices [4]­[7]. Typically, RF MEMS switches-resistivity silicon wafers, gallium arsenide (GaAs) wafers, and quartz substrates using semiconductor Manuscript and surface planarization of wide metal lines prior to deposition of a metal membrane bridge, which poses

  19. EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN SL/98-060 (RF)

    E-Print Network [OSTI]

    Keil, Eberhard

    EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN SL/98-060 (RF) A Recirculating Electron Accelerator will become available after the decommissioning of LEP. The major design features and subjects of further developments are discussed. Geneva, Switzerland October 9, 1998 #12;1 INTRODUCTION The European nuclear physics

  20. ACP-OPLL Photonic Integrated Circuits for High Dynamic Range RF/Photonic links

    E-Print Network [OSTI]

    Coldren, Larry A.

    the local optical phase modulators Laser source RF input ACP-OPLL Phase modulator PD PD Output PhaseB optical coupler and a feedback trace from the photodetector common electrode to the phase modulator common electrode. Through phase tracking the OPLL forces the optical phase of the local ACP phase modulator

  1. A Parametric Study of Electron Extraction from a Low Frequency Inductively Coupled RF-Plasma Source

    E-Print Network [OSTI]

    -cathode is closed only by the ion current to the cathode chamber wall. The extraction of electrons from the rf through this opening is larger than the ion saturation current to the chamber wall, then the maximum by the plasma density in the cathode chamber, the ion Bohm velocity at the sheath edge and the surface area

  2. WTJ(S^rf7?\\ Ris-R-761p*

    E-Print Network [OSTI]

    WTJ(S^rf7?\\ Risø-R-761£p*Thermonuclear Fusion September 1994 #12;ANNUAL PROGRESS _****ig*r REPORT 1993 Work in Controlled Thermonuclear Fusion Research Research Performed in The Fusion Research Unit underthe Contract ofAssociationbetween Euratom and Risø

  3. Development of a 1319-nm Laser Radar Using Fiber Optics and RF Pulse Compression

    E-Print Network [OSTI]

    Kansas, University of

    Development of a 1319-nm Laser Radar Using Fiber Optics and RF Pulse Compression Christopher T of this concept. Our laboratory breadboard uses standard, single-mode optical fiber, off-the-shelf fiber-optic IMPLEMENTATION 3.1 Transmitter--Single-mode laser 3.2 Transmitter--Single-mode fiber 3.3 Transmitter--Optical

  4. Modeling and identification of continuous-time system for RF amplifiers

    E-Print Network [OSTI]

    Boyer, Edmond

    Modeling and identification of continuous-time system for RF amplifiers Mourad Djamai 1 , Smail present a new identification proce- dure for radio frequency Power Amplifier (PA) in the presence signals in time domain. I. INTRODUCTION Numerous approaches in Power Amplifier identification area have

  5. New low-level rf system for the Fermilab Booster synchrotron

    SciTech Connect (OSTI)

    Kerns, C.; Crisp, J.; Kerns, Q.; Miller, H.

    1987-03-01T23:59:59.000Z

    This paper describes the Booster low-level rf system that was constructed to meet these recently added requirements: (1) synthesizer controlled capture frequency at injection, (2) very low-phase noise over the machine cycle, (3) smooth phase-lock of beam to an external reference frequency and (4) ability to accelerate either a full turn or partial turn of beam.

  6. Optical Investigations of Dust Particles Distribution in RF and DC Discharges

    SciTech Connect (OSTI)

    Ramazanov, T. S.; Dosbolayev, M. K.; Jumabekov, A. N.; Amangaliyeva, R. Zh. [Al-Farabi Kazakh National University, IETP, 96a Tole Bi St., Almaty 050012 (Kazakhstan); Filatova, I. I.; Azharonok, V. V. [B. I. Stepanov Institute of Physics NAS of Belarus, Nezavisimosti Ave., 68, 220072, Minsk (Belarus)

    2008-09-07T23:59:59.000Z

    Optical emission spectroscopy is used to study dust particles movement and conditions of a formation of ordered plasma-dust structures in a capacitively coupled RF discharge. 3D binocular diagnostics of plasma-dust structures in dc discharge was made.

  7. Recombination time of an RF discharge plasma in the presence of water molecules

    SciTech Connect (OSTI)

    Protasevich, E.T.

    1986-05-01T23:59:59.000Z

    The authors show that the introduction of water vapor into an electrodeless rf discharge noticeably reduces the excitation temperature and substantially increases the recombination time of the plasma. An attempt is made to explain the physical processes associated with these phenomena.

  8. CRYOGENIC TESTING OF THE RF INPUT WAVEGUIDE FOR THE CEBAF UPGRADE CRYOMODULE*

    E-Print Network [OSTI]

    CRYOGENIC TESTING OF THE RF INPUT WAVEGUIDE FOR THE CEBAF UPGRADE CRYOMODULE* T. Hiatt , M. Breth to support the planned CEBAF upgrade at the Jefferson Lab a new cryomodule has been designed. A key component original CEBAF waveguides. A series of tests were performed on the waveguide to include temperature

  9. A low RF-band impedance spectroscopy based sensor for in-situ, wireless soil sensing

    E-Print Network [OSTI]

    Kumar, Ratnesh

    1 A low RF-band impedance spectroscopy based sensor for in-situ, wireless soil sensing Gunjan of impedance spectroscopy. Impedance measurement at multiple frequencies is done by comparing the amplitude impedance of the board in the measurements to minimize the errors. Measurements of both real and imaginary

  10. TITANIUM NITRIDE COATING AS A MULTIPACTOR SUPPRESSOR ON RF COUPLER CERAMIC WINDOWS*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    TITANIUM NITRIDE COATING AS A MULTIPACTOR SUPPRESSOR ON RF COUPLER CERAMIC WINDOWS* W. Kaabi# , H. The obtained measurements point out how the Nitrogen vacancy on the film can be controlled very well acting a low Secondary Electron Emission Yield (SEY). Titanium Nitride is a good candidate for this purpose

  11. NPN RF Transistor This device is designed for use in low noise UHF/VHF amplifiers

    E-Print Network [OSTI]

    Berns, Hans-Gerd

    NPN RF Transistor This device is designed for use in low noise UHF/VHF amplifiers with collector currents in the 100 µA to 30 mA range in common emitter or common base mode of operation, and in low degrees C. 2) These are steady state limits. The factory should be consulted on applications involving

  12. Analog/RF Design Techniques for High Performance Nanoelectronic On-Chip Interconnects

    E-Print Network [OSTI]

    Liu, Bao

    explores this possibility, espe- cially, application of two analog/RF design techniques as fol- low. 1- mance nanoelectronic on-chip interconnects: (1) application of distributed amplifiers for signal. Application of distributed amplifiers for signal attenua- tion reduction in high performance nanoelectronic on

  13. Structure and magnetic properties of rf thermally plasma synthesized Mn and MnZn ferrite nanoparticles

    E-Print Network [OSTI]

    McHenry, Michael E.

    Structure and magnetic properties of rf thermally plasma synthesized Mn and Mn­Zn ferrite has previously been shown to be a viable route to producing nanocrystalline magnetite and Ni ferrite nanoparticles. In this work nanocrystalline powders of Mn and Mn­Zn ferrites have been synthesized using a 50 k

  14. Synthesis of Nickel-Zinc Ferrites in RF Thermal Plasma Reactor J. Szpvlgyi1,2*

    E-Print Network [OSTI]

    Gubicza, Jenõ

    Synthesis of Nickel-Zinc Ferrites in RF Thermal Plasma Reactor J. Szépvölgyi1,2* , I. Mohai1 , L POB 32, Budapest, Hungary Abstract Nickel-zinc ferrites usually exhibit high saturation mag. In this paper results of thermal plasma synthesis of nanosized nickel-zinc ferrites from oxide powders

  15. Ion Crystals Produced by Laser and Sympathetic Cooling in a Linear RF Ion Trap

    E-Print Network [OSTI]

    Zhu, Feng

    2012-02-14T23:59:59.000Z

    A detailed investigation of ion crystals produced by laser and sympathetic cooling in a linear RF trap has been conducted. The laser cooling methods were examined and applied to the trapped ^24Mg^(positive) ions. The crystals produced by the laser...

  16. RF and Surface Properties of Bulk Niobium and Niobium Film Samples

    E-Print Network [OSTI]

    Junginger, Tobias; Weingarten, Wolfgang

    2012-01-01T23:59:59.000Z

    At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution measurements on bulk niobium and niobium ?lm on copper samples are presented. Surface resistance results are being correlated to surface analyses measurements carried out on the same samples.

  17. RF PULSED TESTS ON 3GHZ NIOBIUM CAVITIES J. Le Duff, C. Thomas

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RF PULSED TESTS ON 3GHZ NIOBIUM CAVITIES J. Le Duff, C. Thomas , G. Bienvenu, H.Sun LAL, Orsay limits have been pushed back thanks to improvements of niobium purity, cavity preparation, as- sembling mT or 50MV/m accelerating field Eacc for TESLA shape bulk niobium (Nb) cavities at T = 0 K

  18. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources

    E-Print Network [OSTI]

    Kurpad, Krishna Nagaraj

    2005-11-01T23:59:59.000Z

    . The channel numbers were marked out on modules A and B. The RF input jack was connected to the input of the power splitter. Eight coaxial cables of increasing length were used to connect the power splitter outputs to the inputs of the attenuator...

  19. Parasitic Characterization of RadioFrequency (RF) Circuits Using MixedMode Simulation

    E-Print Network [OSTI]

    Dutton, Robert W.

    . Introduction For monolithic microwave and RF integrated cir­ cuit applications, accurate modeling of parasitic can vary depending upon the fitting method and the start­ ing guess. In the case of analytical parameter fit­ ting, additional test structures are usually required to consider de­embedding the S

  20. Phase loop bandwidth measurements on the advanced photon source 352 MHz rf systems

    SciTech Connect (OSTI)

    Horan, D.; Nassiri, A.; Schwartz, C.

    1997-08-01T23:59:59.000Z

    Phase loop bandwidth tests were performed on the Advanced Photon Source storage ring 352-MHz rf systems. These measurements were made using the HP3563A Control Systems Analyzer, with the rf systems running at 30 kilowatts into each of the storage ring cavities, without stored beam. An electronic phase shifter was used to inject approximately 14 degrees of stimulated phase shift into the low-level rf system, which produced measureable response voltage in the feedback loops without upsetting normal rf system operation. With the PID (proportional-integral-differential) amplifier settings at the values used during accelerator operation, the measurement data revealed that the 3-dB response for the cavity sum and klystron power-phase loops is approximately 7 kHz and 45 kHz, respectively, with the cavities the primary bandwidth-limiting factor in the cavity-sum loop. Data were taken at various PID settings until the loops became unstable. Crosstalk between the two phase loops was measured.

  1. A 60GHz, 13dBm Fully Integrated 65nm RF-CMOS Power Amplifier

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    simulation. A. Transistor Layout Caracterisation The size of the transistor depends on the maximum powerA 60GHz, 13dBm Fully Integrated 65nm RF-CMOS Power Amplifier Sofiane Aloui, Eric Kerhervé IMS-CNRS University of Toulouse Toulouse, France plana@laas.fr Abstract--A 65nm CMOS, 60GHz fully integrated power

  2. Heterogeneous PLC-RF networking for LLNs Cdric Chauvenet*,** --Bernard Tourancheau*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Heterogeneous PLC-RF networking for LLNs Cédric Chauvenet*,** -- Bernard Tourancheau* * CITI INSA and city automation, our view of the future building networking infrastructure places PLC as the central point. Thanks to the design of converging IPv6 networking layers, we show that merging PLC with existing

  3. A multichannel, real-time MRI RF power monitor for independent SAR determination

    SciTech Connect (OSTI)

    El-Sharkawy, AbdEl-Monem M.; Qian Di; Bottomley, Paul A.; Edelstein, William A. [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland 21287 (United States); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland 21287 (United States) and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21287 (United States); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland 21287 (United States)

    2012-05-15T23:59:59.000Z

    Purpose: Accurate measurements of the RF power delivered during clinical MRI are essential for safety and regulatory compliance, avoiding inappropriate restrictions on clinical MRI sequences, and for testing the MRI safety of peripheral and interventional devices at known RF exposure levels. The goal is to make independent RF power measurements to test the accuracy of scanner-reported specific absorption rate (SAR) over the extraordinary range of operating conditions routinely encountered in MRI. Methods: A six channel, high dynamic range, real-time power profiling system was designed and built for monitoring power delivery during MRI up to 440 MHz. The system was calibrated and used in two 3 T scanners to measure power applied to human subjects during MRI scans. The results were compared with the scanner-reported SAR. Results: The new power measurement system has highly linear performance over a 90 dB dynamic range and a wide range of MRI duty cycles. It has about 0.1 dB insertion loss that does not interfere with scanner operation. The measurements of whole-body SAR in volunteers showed that scanner-reported SAR was significantly overestimated by up to about 2.2 fold. Conclusions: The new power monitor system can accurately and independently measure RF power deposition over the wide range of conditions routinely encountered during MRI. Scanner-reported SAR values are not appropriate for setting exposure limits during device or pulse sequence testing.

  4. Ion transport in macroscopic RF linear traps Jofre Pedregosa-Gutierrez,

    E-Print Network [OSTI]

    Boyer, Edmond

    ´er^ome, 13397 Marseille Cedex 20, France (Dated: July 18, 2014) Abstract Efficient transport of cold atomsIon transport in macroscopic RF linear traps Jofre Pedregosa-Gutierrez, Caroline Champenois, Marius information processing to frequency metrology. Different transport schemes have been developed, which allow

  5. Development of fundamental power coupler for high-current superconducting RF cavity

    SciTech Connect (OSTI)

    Jain P.; Belomestnykh, S.; Ben-Zvi, I.; Xu, W.

    2012-05-20T23:59:59.000Z

    Brookhaven National Laboratory took a project of developing a 704 MHz five-cell superconducting RF cavity for high-current linacs, including Energy Recovery Linac (ERL) for planned electron-hadron collider eRHIC. The cavity will be fed by a high-power RF amplifier using a coaxial Fundamental Power Coupler (FPC), which delivers 20 kW of CW RF power to the cavity. The design of FPC is one of the important aspects as one has to take into account the heat losses dissipated on the surface of the conductor by RF fields along with that of the static heat load. Using a simple simulation model we show the temperature profile and the heat load dissipated along the coupler length. To minimize the heat load on FPC near the cavity end, a thermal intercept is required at an appropriate location on FPC. A 10 K intercept was chosen and its location optimized with our simulation code. The requirement on the helium gas flow rate for the effective heat removal from the thermal intercept is also discussed.

  6. Observation of Liquid Metal Actuation in Microfluidic Channels and Implementation to Tunable RF Inductors 

    E-Print Network [OSTI]

    Dogan, Yusuf

    2014-07-18T23:59:59.000Z

    with an expected speed is achieved. At the end of the study, tunability in an RF inductor using liquid metal as a switching part is provided, once a solution to the nagging oxidation problem of liquid metals is offered, and thus the feasibility of liquid metals...

  7. Ion Crystals Produced by Laser and Sympathetic Cooling in a Linear RF Ion Trap 

    E-Print Network [OSTI]

    Zhu, Feng

    2012-02-14T23:59:59.000Z

    A detailed investigation of ion crystals produced by laser and sympathetic cooling in a linear RF trap has been conducted. The laser cooling methods were examined and applied to the trapped ^24Mg^(positive) ions. The crystals produced by the laser...

  8. Laser cooling and sympathetic cooling in a linear quadrupole rf trap 

    E-Print Network [OSTI]

    Ryjkov, Vladimir Leonidovich

    2005-02-17T23:59:59.000Z

    An investigation of the sympathetic cooling method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap...

  9. Ambient-RF-Energy-Harvesting Sensor Node with Capacitor-Leakage-Aware Duty Cycle Control

    E-Print Network [OSTI]

    Tentzeris, Manos

    shortage risk. (2) Adaptive optimal operation point tracking considering harvested energy variability. (3Ambient-RF-Energy-Harvesting Sensor Node with Capacitor-Leakage-Aware Duty Cycle Control Ryo-- In this paper, we present a software control method that maximizes the sensing rate of wireless sensor networks

  10. A Wireless Sensing Platform Utilizing Ambient RF Energy Aaron N. Parks 1

    E-Print Network [OSTI]

    Hochberg, Michael

    to store as much energy. When the requirement for on-board energy storage decreases, a smaller (longer the minimal energy storage needed for the RF harvesting sensor node to operate. A modern RFID tag, which in urban environments (cellular BTS). Antenna Matching & Charge pump System Controller (TI MSP430) 2.4GHz

  11. TESLA Report 2004-02 Anti-multipactor TiN coating of RF power

    E-Print Network [OSTI]

    N layers generation on surfaces which were not protected in this way previously. Thin TiN films on ceramicTESLA Report 2004-02 1 Anti-multipactor TiN coating of RF power coupler components for TESLA performance of couplers) J. Lorkiewicz1 , The Andrzej Soltan Institute for Nuclear Studies, Pl 05-400 Otwock

  12. Low-frequency RF Coupling To Unconventional (Fat Unbalanced) Dipoles

    SciTech Connect (OSTI)

    Ong, M M; Brown, C G; Perkins, M P; Speer, R D; Javedani, J B

    2010-12-07T23:59:59.000Z

    The report explains radio frequency (RF) coupling to unconventional dipole antennas. Normal dipoles have thin equal length arms that operate at maximum efficiency around resonance frequencies. In some applications like high-explosive (HE) safety analysis, structures similar to dipoles with ''fat'' unequal length arms must be evaluated for indirect-lightning effects. An example is shown where a metal drum-shaped container with HE forms one arm and the detonator cable acts as the other. Even if the HE is in a facility converted into a ''Faraday cage'', a lightning strike to the facility could still produce electric fields inside. The detonator cable concentrates the electric field and carries the energy into the detonator, potentially creating a hazard. This electromagnetic (EM) field coupling of lightning energy is the indirect effect of a lightning strike. In practice, ''Faraday cages'' are formed by the rebar of the concrete facilities. The individual rebar rods in the roof, walls and floor are normally electrically connected because of the construction technique of using metal wire to tie the pieces together. There are two additional requirements for a good cage. (1) The roof-wall joint and the wall-floor joint must be electrically attached. (2) All metallic penetrations into the facility must also be electrically connected to the rebar. In this report, it is assumed that these conditions have been met, and there is no arcing in the facility structure. Many types of detonators have metal ''cups'' that contain the explosives and thin electrical initiating wires, called bridge wires mounted between two pins. The pins are connected to the detonator cable. The area of concern is between the pins supporting the bridge wire and the metal cup forming the outside of the detonator. Detonator cables usually have two wires, and in this example, both wires generated the same voltage at the detonator bridge wire. This is called the common-mode voltage. The explosive component inside a detonator is relatively sensitive, and any electrical arc is a concern. In a safety analysis, the pin-to-cup voltage, i.e., detonator voltage, must be calculated to decide if an arc will form. If the electric field is known, the voltage between any two points is simply the integral of the field along a line between the points. Eq. 1.1. For simplicity, it is assumed that the electric field and dipole elements are aligned. Calculating the induced detonator voltage is more complex because of the field concentration caused by metal components. If the detonator cup is not electrically connected to the metal HE container, the portion of the voltage generated by the dipole at the detonator will divide between the container-to-cup and cup-to-pin gaps. The gap voltages are determined by their capacitances. As a simplification, it will be assumed the cup is electrically attached, short circuited, to the HE container. The electrical field in the pin-to-cup area is determined by the field near the dipole, the length of the dipole, the shape of the arms, and the orientation of the arms. Given the characteristics of a lightning strike and the inductance of the facility, the electric fields in the ''Faraday cage'' can be calculated. The important parameters for determining the voltage in an empty facility are the inductance of the rebars and the rate of change of the current, Eq. 1.3. The internal electric fields are directly related to the facility voltages, however, the electric fields in the pin-to-cup space is much higher than the facility fields because the antenna will concentrate the fields covered by the arms. Because the lightning current rise-time is different for every strike, the maximum electric field and the induced detonator voltage should be described by probability distributions. For pedantic purposes, the peak field in the simulations will be simply set to 1 V/m. Lightning induced detonator voltages can be calculated by scaling up with the facility fields. Any metal object around the explosives, such as a work stand, will also distort the electric

  13. Structure Analysis of a Precipitate Phase in an Ni-Rich High Temperature NiTiHf Shape Memory Alloy

    SciTech Connect (OSTI)

    Yang, Fan; Coughlin, D. R.; Phillips, Patrick J.; Yang, L.; Devaraj, Arun; Kovarik, Libor; Noebe, Ronald D.; Mills, M. J.

    2013-03-22T23:59:59.000Z

    Thermal aging of the high temperature shape memory alloy 50.3Ni-29.7Ti-20Hf (at.%) introduces a novel precipitate phase, which plays an important role in improving shape memory properties. The precipitate phase was investigated by conventional electron diffraction, high resolution scanning transmission electron microscopy (STEM) and three dimensional atom probe tomography. An unrelaxed orthorhombic atomic structural model is proposed based on these observations. This model was subsequently relaxed by ab initio calculations. As a result of the relaxation, atom shuffle displacements occur, which in turn yields improved agreement with the STEM images. The relaxed structure, which is termed the “H-phase”, has also been verified to be thermodymanically stable at 0 K.

  14. JOURNAL DE PHYSIQUE Colloque C6, suppldment au no 12, Tome 37, Ddcembre 1976, page C6-535 MOSSBAUER SPECTROSCOPIC STUDIES OF THE HF INTERACTION

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    JOURNAL DE PHYSIQUE Colloque C6, suppldment au no 12, Tome 37, Ddcembre 1976, page C6-535 MOSSBAUER, Denmark RBsum6. - La structure hyperfine paramagnktique des spectres Mossbauer des complexes [Fe(H20)6-n defluor. Abstract. - The paramagnetic hf structure in Mossbauer spectra of [Fe(H20)6-nFn]3-n complexes

  15. Quantum dynamics of molecular multiphoton excitation in intense laser and static electric fields: Floquet theory, quasienergy spectra, and application to the HF molecule

    E-Print Network [OSTI]

    Chu, Shih-I; Tietz, James V.; Datta, Krishna K.

    1982-01-01T23:59:59.000Z

    of the HF molecule as functions of field strengths and frequency. Nonlinear effects such as power broadening, dynamic Stark shift, Autler–Townes multiplet splitting, hole burning, and S?hump behaviors, etc., are observed and discussed in terms of quasienergy...

  16. Structural and electronic properties of cubic HfO2 surfaces G.H. Chen, Z.F. Hou, X.G. Gong *

    E-Print Network [OSTI]

    Gong, Xingao

    Structural and electronic properties of cubic HfO2 surfaces G.H. Chen, Z.F. Hou, X.G. Gong@fudan.edu.cn (X.G. Gong). www.elsevier.com/locate/commatsci Available online at www

  17. JOURNAL OF GEOPHYSICAL RESEARCH: SPACE PHYSICS, VOL. 118, 111, doi:10.1002/jgra.50558, 2013 100 days of ELF/VLF generation via HF heating with HAARP

    E-Print Network [OSTI]

    days of ELF/VLF generation via HF heating with HAARP M. B. Cohen1 and M. Golkowski2 Received 20 June Frequency Active Auroral Research Program (HAARP) facility near Gakona, Alaska, at a variety of ELF injected into the waveguide and reaching 250 km. The median power generated by HAARP and injected

  18. Ion heating, burnout of the HF field and ion sound generation under the development of a modulation instability of an intense Langmuir wave in a plasma

    E-Print Network [OSTI]

    Kirichok, A V; Pryimak, A V; Zagorodny, A G

    2015-01-01T23:59:59.000Z

    The development of one-dimensional parametric instabilities of intense long-wave plasma waves is considered in terms of the so-called hybrid models, when electrons are treated as a fluid and ions are regarded as particles. The analysis is performed for both cases when the average plasma field energy is lower (Zakharov's hybrid model -- ZHM) or greater (Silin's hybrid model -- SHM) than the plasma thermal energy. The efficiency of energy transfer to ions and to ion perturbations under the development of the instability is considered for various values of electron-to-ion mass ratios. The energy of low-frequency (LF) oscillations (ion-sound waves) is found to be much lower than the final ion kinetic energy. We also discuss the influence of the changes in the damping rate of the high-frequency (HF) field on the instability development. Reduced absorption of the HF field leads to the retardation of the HF field burnout within plasma density cavities and to the broadening of the HF spectrum. At the same time, the i...

  19. Microstructure characterization and electrical transport of nanocrystalline ZrO{sub 2}–CeO{sub 2} solid solution

    SciTech Connect (OSTI)

    Saha, S. [Department of Physics, National Institute of Technology, Durgapur, Burdwan 713209, West Bengal (India); Dutta, H. [Department of Physics, Vivekananda College, Burdwan 713103, West Bengal (India); Meikap, A.K., E-mail: meikapnitd@yahoo.com [Department of Physics, National Institute of Technology, Durgapur, Burdwan 713209, West Bengal (India); Pradhan, S.K., E-mail: skp_bu@yahoo.com [Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: • Monoclinic ZrO{sub 2} phase has been changed to cubic ZrO{sub 2} phase within a short milling. • Conductivity increases due to change of phase from monoclinic to cubic. • A maximum has been observed in the s–T curve. • A transformation from ?ve to +ve ac magnetoconductance has been observed. - Abstract: Nanocrystalline ZrO{sub 2}–CeO{sub 2} (ZC) solid solution is synthesized by high energy ball-milling the powder mixture of monoclinic (m) ZrO{sub 2}–10 mol% CeO{sub 2} in air medium. X-ray powder diffraction (XRD) patterns show that the method IS effective to synthesize cubic (c) ZrO{sub 2} phase within a short milling time. Formation mechanism, structural and microstructural changes of different phases and relative phase abundances have been estimated by Rietveld analysis of XRD patterns. The dc conductivity has been enhanced due to monoclinic to cubic phase transformation. A transformation from small polaron hopping to correlated barrier hoping has been observed from the of temperature dependence frequency exponent study. A crossover from negative to positive ac magnetoconductance has been observed at temperature T = 280 K and 230 K for unmilled (ZC0H) and 8 h (ZC8H) milled samples, respectively.

  20. Light-induced structural changes in Eu-doped (Pb,La)(Zr,Ti)O{sub 3} ceramics

    SciTech Connect (OSTI)

    Myint, Thandar; Gunawidjaja, Ray; Eilers, Hergen [Applied Sciences Laboratory, Institute for Shock Physics, Washington State University, Spokane, Washington 99210-1495 (United States)

    2011-04-25T23:59:59.000Z

    Fluorescence spectra of poled and unpoled Eu-doped (Pb,La)(Zr,Ti)O{sub 3} ceramics with various compositions were measured using 580 nm excitation. The ratio of the intensities of the Eu{sup 3+} {sup 5}D{sub 0}{yields}{sup 7}F{sub 2}/{sup 5}D{sub 0}{yields}{sup 7}F{sub 1} fluorescence transitions was used as an indicator for the symmetry of the Eu{sup 3+} site. As the symmetry decreases, the ratio increases. Increasing the Zr content in (Pb,La)(Zr,Ti)O{sub 3} increases the ratio, indicating that the symmetry of the Eu{sup 3+} site decreases. Exposure of the Eu-doped (Pb,La)(Zr,Ti)O{sub 3} samples to UV light also increases the intensity ratio, indicating that UV light exposure leads to structural distortions in Eu-doped (Pb,La)(Zr,Ti)O{sub 3} samples, lowering the Eu{sup 3+} site symmetry.

  1. Predictions of VRF on a Langmuir Probe under the RF Heating Spiral on the Divertor Floor on NSTX-U

    SciTech Connect (OSTI)

    Hosea, J C [PPPL; Perkins, R J [PPPL; Jaworski, M A [PPPL; Kramer, G J [PPPL; Ahn, J-W [ORNL

    2014-07-01T23:59:59.000Z

    RF heating deposition spirals are observed on the divertor plates on NSTX as shown in for a NB plus RF heating case. It has been shown that the RF spiral is tracked quite well by the spiral mapping of the strike points on the divertor plate of magnetic field lines passing in front of the high harmonic fast wave (HHFW) antenna on NSTX. Indeed, both current instrumented tiles and Langmuir probes respond to the spiral when it is positioned over them. In particular, a positive increment in tile current (collection of electrons) is obtained when the spiral is over the tile. This current can be due to RF rectification and/or RF heating of the scrape off layer (SOL) plasma along the magnetic field lines passing in front of the the HHFW antenna. It is important to determine quantitatively the relative contributions of these processes. Here we explore the properties of the characteristics of probes on the lower divertor plate to determine the likelyhood that the primary cause of the RF heat deposition is RF rectification.

  2. Metastable phases determination of U-2.5Zr-7.5Nb and U-3.0Zr-9.0Nb alloys by Rietveld method

    SciTech Connect (OSTI)

    Dias Pais, R. W.; Dos Santos, A. M. M.; Lameiras, F. S.; Cantagalli, N. M.; De Paula, R. G.; Ferraz, W. B. [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, CNEN, Av. Presidente Antonio Carlos 6.627, 31270-901 - Belo Horizonte, MG (Brazil)

    2012-07-01T23:59:59.000Z

    The Rietveld refinement has been employed for study of metastable phase of alloys U-2.5Zr-7.5Nb(wt%) and U-3Zr-9Nb(wt%). The ingots of both alloys were produced in vacuum induction furnace at temperature of about 1500 deg.C followed by cooling to room temperature. The samples with 2.5 cm in diameter and 0.3 cm of thickness was homogenized at 1000 deg.C/16 hours and treated isothermally at (i) 600 deg.C for 0.5, 3 and 24 hours and (ii) 300 deg.C for 4 minutes, 20 minutes and 17.5 hours. At the end of each treatment the samples were water quenched. Data from X-ray diffraction were collected at room temperature with a Rigaku diffractometer D Max-RAPID radiation Cuk{alpha} using steps of 0.02 deg. (2{theta}) with scan angle in the range of 20-80 deg. (2{theta}). The full diffraction pattern was analyzed by the Rietveld method using the GSAS program. The result shows that the non-resolved appearance of the XRD patterns added to the proximity of the Bragg reflections of the transition phase makes the refinement of alloys a challenging task. For the isothermal treatment at 600 deg.C during 0.5 and 3 hours both alloys showed the majority presence of {gamma}{sup S} phase fallow by {gamma}{sup 0} phase in minor amounts. For 24 hours at 600 deg.C occurred the decomposition of phases with the presence of {gamma}{sup S} + {alpha}. Isothermal treatment at 300 deg.C for both alloys is characterized by the presence of phases {gamma}{sup 0} + {alpha}'' where the concentration of the {alpha}'' phase increases with time of heat treatment. (authors)

  3. Production of stable, non-thermal atmospheric pressure rf capacitive plasmas using gases other than helium or neon

    DOE Patents [OSTI]

    Park, Jaeyoung; Henins, Ivars

    2005-06-21T23:59:59.000Z

    The present invention enables the production of stable, steady state, non-thermal atmospheric pressure rf capacitive .alpha.-mode plasmas using gases other than helium and neon. In particular, the current invention generates and maintains stable, steady-state, non-thermal atmospheric pressure rf .alpha.-mode plasmas using pure argon or argon with reactive gas mixtures, pure oxygen or air. By replacing rare and expensive helium with more readily available gases, this invention makes it more economical to use atmospheric pressure rf .alpha.-mode plasmas for various materials processing applications.

  4. An rf-carpet electrospray ion source to provide isobaric mass calibrants for trans-uranium elements

    E-Print Network [OSTI]

    S. Naimi; S. Nakamura; Y. Ito; H. Mita; K. Okada; A. Ozawa; P. Schury; T. Sonoda; A. Takamine; M. Wada; H. Wollnik

    2012-12-16T23:59:59.000Z

    For trans-uranium elements, stable atomic isobars do not exist. In order to provide isobaric reference ions for the mass measurement of trans-uranium elements, an electrospray ion source (ESI) was combined with an rf-carpet to collect molecular ions efficiently. The rf-carpet allows for simplification of the pumping system to transport ions from the ESI to a precision mass analyzer. Molecular ions appropriate for isobaric references of trans-uranium elements were extracted from the rf-carpet and analyzed by a multi-reflection time-of-flight mass spectrograph (MRTOF-MS) with a resolving power of $\\rm{R_m} \\gtrsim100,000$.

  5. Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation

    SciTech Connect (OSTI)

    Zhang, Ming [University of Cambridge; Boatner, Lynn A [ORNL; Salje, Ekhard K.H. [University of Cambridge; Honda, Shin-ichi [ORNL; Ewing, Rodney C. [University of Michigan

    2008-01-01T23:59:59.000Z

    The structural variations of synthetic zircon (ZrSiO{sub 4}) single crystals irradiated at room temperature by 280 keV Pb{sup +} ions (with fluences up to 1 x 10{sup 15} ions/cm{sup 2}) were investigated using infrared (IR) spectroscopy. Like metamict zircon whose crystal structure is damaged and amorphized by naturally occurring {alpha}-decay events, the Pb{sup +}-irradiated zircon crystals show a dramatic decrease in reflectivity. However, no significant decrease in wavenumbers of the stretching vibrations of SiO{sub 4} tetrahedra in zircon was detected. The Pb{sup +}-implanted zircon exhibits new IR bands, indicating irradiation-induced new vibrations or domains, clusters or phases in addition to SiO{sub 2} and ZrO{sub 2}. IR features consistent with those of Pb silicates (with a divalent state, i.e., Pb{sup 2+}) are also found in the irradiated sample. This finding implies that some of the radiogenic Pb in natural zircon might not actually reside in the zircon lattice or in ZrSiO{sub 4} phases, but form new local domains or clusters. Infrared bands of OH-stretching vibrations were also detected in the irradiated synthetic zircon, which was originally free from OH features prior to the irradiation. These results indicate that H can easily diffuse into the irradiated layer or into irradiated-induced phases to form OH or and hydrous species after the irradiated material is damaged. The type and content of hydrous species vary with irradiation fluences.

  6. EUREM 12, Brno, Czech Republic, July 9-14, 2000 P 257 High yield incorporation of ZrCl4 into single wall carbon nanotubes

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    in a furnace, held at temperature for 1hr and then furnace cooled. The specimens were characterised using) show the filling product obtained from as-supplied ZrCl4. Figure 1(a) shows an empty SWNT tip. Below beam. The average filling yield for `as-supplied' ZrCl4 was estimated to be between 20-30%. #12;P 258

  7. Beta-decay properties of Zr and Mo neutron-rich isotopes

    E-Print Network [OSTI]

    P. Sarriguren; J. Pereira

    2010-06-08T23:59:59.000Z

    Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron emission are investigated in neutron-rich Zr and Mo isotopes within a deformed quasiparticle random-phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. Comparison with recent measurements of half-lives stresses the important role that nuclear deformation plays in the description of beta-decay properties in this mass region.

  8. WG-MOX Fuel Zr-tube Neutron Spectrum Comparison in ATR and PWR

    SciTech Connect (OSTI)

    Gray S. Chang

    2005-02-01T23:59:59.000Z

    An experiment containing WG-MOX fuel has been designed and irradiated from 1998 to 2004 in the Advanced Test Reactor (ATR) at the Idaho National Engineering and Environmental Laboratory (INEEL). Important neutronics parameters were computed using novel Monte Carlo methods. The purpose of this summary is to compare the Weapons-Grade Mixed Oxide fuel (WG-MOX) Zr-tube’s neutron spectrum in ATR and PWR. The results indicate that the Zrtube’s neutron spectrum in ATR are softer than in PWR.

  9. Electron microscopy of phase and structural transformations in soft magnetic nanocrystalline Fe-Zr-N films

    SciTech Connect (OSTI)

    Zhigalina, O. M., E-mail: zhigal@ns.crys.ras.ru; Khmelenin, D. N. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Sheftel', E. N.; Usmanova, G. Sh. [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation)] [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation); Vasil'ev, A. L. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Carlsson, A. [FEI Company (Netherlands)] [FEI Company (Netherlands)

    2013-03-15T23:59:59.000Z

    The effect of deposition conditions (film thickness) on the structure of soft magnetic Fe{sub 80-78}Zr{sub 10}N{sub 10-12} films formed by reactive magnetron deposition on a heat-resistant glass substrate has been investigated by analytical transmission electron microscopy, high-resolution electron microscopy, and diffraction analysis. The processes of evolution of the phase and structural state of films and the film-substrate interface upon annealing in the temperature range of 200-650 Degree-Sign C have been analyzed taking into account the thermodynamic, kinetic, and structural factors and the specific features of the nanocrystalline state.

  10. Fundamental science investigations to develop a 6-MV laser triggered gas switch for ZR: first annual report.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Van Den Avyle, James A.; Lehr, Jane Marie; Rose, David (Voss Scientific, Albuquerque, NM); Krompholz, Hermann G. (Texas Tech University, Lubbock, TX); Vela, Russell (Texas Tech University, Lubbock, TX); Jorgenson, Roy Eberhardt; Timoshkin, Igor (University of Strathclyde, Glasgow, Scotland); Woodworth, Joseph Ray; Prestwich, Kenneth Randel (Voss Scientific, Albuquerque, NM); Krile, John (Texas Tech University, Lubbock, TX); Given, Martin (University of Strathclyde, Glasgow, Scotland); McKee, G. Randall; Rosenthal, Stephen Edgar; Struve, Kenneth William; Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Benwell, Andrew L. (University of Missouri-Columbia, Columbia, Missouri); Kovaleski, Scott (University of Missouri-Columbia, Columbia, Missouri); LeChien, Keith, R.; Johnson, David (Titan Pulse Sciences Division); Fouracre, R.A. (University of Strathclyde, Glasgow, Scotland); Yeckel, Chris (University of Missouri-Columbia, Columbia, Missouri); Wakeland, Peter Eric (Ktech Corporation, Albuquerque, NM); Miller, A. R. (Titan Pulse Sciences Division); Hodge, Keith Conquest (Ktech Corporation, Albuquerque, NM); Pasik, Michael Francis; Savage, Mark Edward; Maenchen, John Eric; Curry, Randy D. (University of Missouri-Columbia, Columbia, Missouri); Feltz, Greg (Ktech Corporation, Albuquerque, NM); Bliss, David Emery; MacGregor, Scott (University of Strathclyde, Glasgow, Scotland); Corley, J. P. (Ktech Corporation, Albuquerque, NM); Anaya, Victor (Ktech Corporation, Albuquerque, NM); Wallace, Zachariah (Ktech Corporation, Albuquerque, NM); Thoma, Carsten (Voss Scientific, Albuquerque, NM); Neuber, Andreas. (Texas Tech University, Lubbock, TX)

    2007-03-01T23:59:59.000Z

    In October 2005, an intensive three-year Laser Triggered Gas Switch (LTGS) development program was initiated to investigate and solve observed performance and reliability issues with the LTGS for ZR. The approach taken has been one of mission-focused research: to revisit and reassess the design, to establish a fundamental understanding of LTGS operation and failure modes, and to test evolving operational hypotheses. This effort is aimed toward deploying an initial switch for ZR in 2007, on supporting rolling upgrades to ZR as the technology can be developed, and to prepare with scientific understanding for the even higher voltage switches anticipated needed for future high-yield accelerators. The ZR LTGS was identified as a potential area of concern quite early, but since initial assessments performed on a simplified Switch Test Bed (STB) at 5 MV showed 300-shot lifetimes on multiple switch builds, this component was judged acceptable. When the Z{sub 20} engineering module was brought online in October 2003 frequent flashovers of the plastic switch envelope were observed at the increased stresses required to compensate for the programmatically increased ZR load inductance. As of October 2006, there have been 1423 Z{sub 20} shots assessing a variety of LTGS designs. Numerous incremental and fundamental switch design modifications have been investigated. As we continue to investigate the LTGS, the basic science of plastic surface tracking, laser triggering, cascade breakdown, and optics degradation remain high-priority mission-focused research topics. Significant progress has been made and, while the switch does not yet achieve design requirements, we are on the path to develop successively better switches for rolling upgrade improvements to ZR. This report summarizes the work performed in FY 2006 by the large team. A high-level summary is followed by detailed individual topical reports.

  11. Intrinsic nanostructure in Zr2 xFe4Si16 y (x = 0.81, y = 6.06)

    SciTech Connect (OSTI)

    Smith, G J [Stony Brook University, Department of Physics and Astronomy; Simonson, Jack [Stony Brook University (SUNY); Prozorov, R. [Ames Laboratory and Iowa State University; Zhu, Y [Brookhaven National Laboratory (BNL); Aronson, M. [Stony Brook University, Department of Physics and Astronomy

    2014-01-01T23:59:59.000Z

    We present a study of the crystal structure and physical properties of single crystals of a new Fe-based ternary compound, Zr2 xFe4Si16 y (x = 0.81, y = 6.06). Zr1.19Fe4Si9.94 is a layered compound, where stoichiometric -FeSi2-derived slabs are separated by Zr-Si planes with substantial numbers of vacancies. High resolution transmission electron microscopy (HRTEM) experiments show that these Zr-Si layers consist of 3.5 nm domains where the Zr and Si vacancies are ordered within a supercell sixteen times the volume of the stoichiometric cell. Within these domains, the occupancies of the Zr and Si sites obey symmetry rules that permit only certain compositions, none of which by themselves reproduce the average composition found in x-ray diffraction experiments. Magnetic susceptibility and magnetization measurements reveal a small but appreciable number of magnetic moments that remain freely fluctuating to 1.8 K, while neutron diffraction confirms the absence of bulk magnetic order with a moment of 0.2 B or larger down to 1.5 K. Electrical resistivity measurements find that Zr1.19Fe4Si9.94 is metallic, and the modest value of the Sommerfeld coefficient of the specific heat = C/T suggests that quasi-particle masses are not particularly strongly enhanced. The onset of superconductivity at Tc 6 K results in a partial resistive transition and a small Meissner signal, although a bulk-like transition is found in the specific heat. Sharp peaks in the ac susceptibility signal the interplay of the normal skin depth and the London penetration depth, typical of a system in which nano-sized superconducting grains are separated by a non-superconducting host. Ultra low field differential magnetic susceptibility measurements reveal the presence of a surprisingly large number of trace magnetic and superconducting phases, suggesting that the Zr-Fe-Si ternary system could be a potentially rich source of new bulk superconductors.

  12. Preliminary study of niobium alloy contamination by transport through helium. [Nb-1Zr; Sm-Co; Hiperco 50 steel; alumina

    SciTech Connect (OSTI)

    Scheuermann, C.M.; Moore, T.J.; Wheeler, D.R.

    1987-01-12T23:59:59.000Z

    Preliminary tests were conducted to determine if interstitial element transport through a circulating helium working fluid was a potential problem in Brayton and Stirling space power systems. Test specimens exposed to a thermal gradient for up to 3000 h included Nb-1%Zr, a Sm-Co alloy, Hiperco 50 steel, and alumina to simulate various engine components of the Brayton and Stirling systems. Results indicate that helium transport of interstitial contaminants can be minimized over a 7-y life with monometallic Nb-1%Zr design. Exposure with other materials indicated a potential for interstitial contaminant transport.

  13. Improved high temperature refractory. [MgCr/sub 2/O/sub 4/ composite with ZrO/sub 2/

    DOE Patents [OSTI]

    Singh, J.P.; James, J.; Picciolo, J.J.

    1985-12-10T23:59:59.000Z

    A high chromia refractory composite has been developed with improved thermal shock resistance and containing about 5 to 30 wt % of unstabilized ZrO/sub 2/ having a temperature-dependent phase change resulting in large expansion mismatch between the ZrO/sub 2/ and the chromia matrix which causes microcracks to form during cooling in the high chromia matrix. The particle size preferably is primarily between about 0.6 to 5 microns and particularly below about 3 microns with an average size in the order of 1.2 to 1.8 microns.

  14. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, Douglas C. (Idaho Falls, ID); Porter, Douglas L. (Idaho Falls, ID); Hayes, Steven L. (Idaho Falls, ID); Hill, Robert N. (Bolingbrook, IL)

    1999-01-01T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both.

  15. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    SciTech Connect (OSTI)

    Crawford, Douglas C.; Porter, Douglas L.; Hayes, Steven L.; Hill, Robert N.

    1997-12-01T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr-Hf alloy or an alloy of Pu-Zr-Hf or a combination of both.

  16. Fuel element design for the enhanced destruction of plutonium in a nuclear reactor

    DOE Patents [OSTI]

    Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Hill, R.N.

    1999-03-23T23:59:59.000Z

    A uranium-free fuel for a fast nuclear reactor comprising an alloy of Pu, Zr and Hf, wherein Hf is present in an amount less than about 10% by weight of the alloy. The fuel may be in the form of a Pu alloy surrounded by a Zr--Hf alloy or an alloy of Pu--Zr--Hf or a combination of both. 7 figs.

  17. A new approach to calculate the transport matrix in RF cavities

    SciTech Connect (OSTI)

    Eidelman, Yu.; /Novosibirsk, IYF; Mokhov, N.; Nagaitsev, S.; Solyak, N.; /Fermilab

    2011-03-01T23:59:59.000Z

    A realistic approach to calculate the transport matrix in RF cavities is developed. It is based on joint solution of equations of longitudinal and transverse motion of a charged particle in an electromagnetic field of the linac. This field is a given by distribution (measured or calculated) of the component of the longitudinal electric field on the axis of the linac. New approach is compared with other matrix methods to solve the same problem. The comparison with code ASTRA has been carried out. Complete agreement for tracking results for a TESLA-type cavity is achieved. A corresponding algorithm will be implemented into the MARS15 code. A realistic approach to calculate the transport matrix in RF cavities is developed. Complete agreement for tracking results with existed code ASTRA is achieved. New algorithm will be implemented into MARS15 code.

  18. Simulations of Ion Migration in the LCLS RF Gun and Injector

    SciTech Connect (OSTI)

    Brachmann, Axel; /SLAC; Dowell, David; /SLAC

    2012-06-25T23:59:59.000Z

    The motivation for this work was the observed surface contamination of the first LCLS RF gun copper cathode. We will present the results of simulations in regards to ion migration in the LCLS gun. Ions of residual gases will be created by interaction of molecular gas species with the UV drive laser beam and by the electron beam itself. The larger part of those ionized molecules remain in the vicinity of creation, are transported towards beam line walls or away from the cathode. However a small fraction gains enough kinetic energy, focused by RF and magnetic fields and propagates to the cathode, producing an undesirable increase of the cathode's surface work function. Although this fraction is small, during long term operation, this effect may become a significant factor limiting the source performance.

  19. Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation

    SciTech Connect (OSTI)

    Stratakis, D.; Gallardo, J.; Palmer, R.B.

    2011-03-28T23:59:59.000Z

    Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Our results agree with current experimental data. Two specific examples illustrate the implementation of magnetic insulation into prospective particle accelerator applications. The ultimate goal of several research efforts is to integrate high-gradient radio-frequency (rf) structures into next generation particle accelerators. For instance, the Muon Accelerator Program is looking at developing low-frequency cavities for muon cooling, and the International Linear Collider is optimizing the performance of 1.3 GHz rf structures aimed at designing a 1 TeV electron-positron collider. Furthermore, the High Gradient RF Collaboration is examining high frequency (f > 10 GHz) structures intended for an electron-positron collider operating at energies in the TeV range. In all this research, the accelerating gradient will be one of the crucial parameters affecting their design, construction, and cost. Limitations from rf breakdown strongly influence the development of accelerators since it limits the machine's maximum gradient. The emission of electrons from the cavity surfaces seemingly is a necessary stage in the breakdown process, acting either as a direct cause of breakdown or as precursor for other secondary effects. Typically, electron currents arise from sharp edges or cracks on the cavities surfaces, where the strength of the electric field is strongly enhanced compared to that of the nominal field when the surfaces of the cavity are perfect planes. Subsequently, a stream of emitted electrons can be accelerated by the rf electric field toward the opposing cavity walls. Upon impact, they heat a localized region, resulting in the eventual breakdown by a variety of secondary mechanisms. Therefore, it is advantageous to develop techniques that could suppress field emission within rf cavities. It has been proposed that high voltages up to about a gigavolt range may be sustained in voltage transformers, by adopting the principle of magnetic insulation in ultrahigh vacuum. The basic idea is to suppress field emission by applying a suitably directed magnetic field of sufficient strength to force the electrons orbits back on to the rf emitting surface. More recently, it was shown that magnetic insulation could be very effective in suppressing field emission and multipacting in rectangular coupler waveguides. Hence, the question arises whether the same principle is applicable to rf accelerating structures. In this Letter, we shall consider application of the concept to low-frequency (201-805 MHz) muon accelerator cavities.

  20. Operator interface for the PEP-II low level RF control system

    SciTech Connect (OSTI)

    Allison, S.; Claus, R.

    1997-05-01T23:59:59.000Z

    This paper focuses on the operational aspects of the low level RF control system being built for the PEP-II storage rings at SLAC. Subsystems requiring major operational considerations include displays for monitor and control from UNIX workstations, slow feedback loops and control sequences residing on microprocessors, and various client applications in the existing SLAC Linear Collider (SLC) control system. Since commissioning of PEP-II RF is currently in-progress, only those parts of the control system used during this phase are discussed in detail. Based on past experience with the SLC control system, it is expected that effort expended during commissioning on a solid user interface will result in smoother transition to full reliable 24-hour-a-day operation.