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1

The role of oxygen-related defects and hydrogen impurities in HfO2 and ZrO2  

Science Conference Proceedings (OSTI)

We investigate the properties of oxygen-related defects and hydrogen impurities in monoclinic HfO"2 and ZrO"2 using first-principles calculations based on a hybrid functional. We examine how the formation energy of these defects depend on the Fermi level ... Keywords: Defects in semiconductors, First-principles calculations, HfO2, High-k dielectrics, Hydrogen impurities, Oxygen interstitial, Oxygen vacancy, Sources of fixed charge, ZrO2

J. L. Lyons; A. Janotti; C. G. Van de Walle

2011-07-01T23:59:59.000Z

2

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

DOE Patents (OSTI)

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.

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

1993-01-01T23:59:59.000Z

3

Cyclic nanoindentation studies on CrN thin films prepared by RF sputtering on Zr-based metallic glass  

Science Conference Proceedings (OSTI)

Cyclic nanoindentation tests were carried out to study the influence of the chromium nitride thin films on the mechanical properties of Zr-based metallic glass. Chromium nitride thin coatings have been deposited on Zr{sub 50}Cu{sub 40}Al{sub 10} metallic glass substrate by RF sputtering. The deposition process was done at room temperature under nitrogen reactive gas using a metallic chromium target. The CrN films have a thickness of 300 nm. Several cyclic nanoindentation measurements were conducted on CrN films and Zr{sub 50}Cu{sub 40}Al{sub 10} metallic glass substrate samples at various loading rate values. We have found that the coated metallic glass sample shows high mechanical properties such as hardness and reduced elastic modulus. Cyclic nanoindentation results show a hardening behaviour for these CrN coatings. Moreover, the CrN coated on Zr-based metallic glass was found to have a high value of resistance to crack propagation, as being analysed through the SEM pictures of the residual Vickers indentation impressions.

Jellad, A.; Benameur, T. [Laboratoire de Genie Mecanique LGM-MA05, ENIM, Av. Ibn El Jazzar, 5019 Monastir (Tunisia); Labdi, S. [Laboratoire d'etudes des Milieux Nanometriques, UEVE, Bd F. Mitterand, 91025 Evry Cedex (France)

2011-01-17T23:59:59.000Z

4

rf  

NLE Websites -- All DOE Office Websites (Extended Search)

RF RF It's what makes the protons go 'round. The latest in a series explaining particle physics in everyday language. Painless Physics Articles BEAM COOLING August 2, 1996 By Leila Belkora, Office of Public Affairs ACCELERATION August 16, 1996 By Dave Finley, Accelerator Division Head RF August 30, 1996 By Pat Colestock, Accelerator Division FIXED TARGET PHYSICS September 20, 1996 By Peter H. Garbincius, Physics Section FIXED TARGET PHYSICS PART DEUX October 16, 1996 By Peter H. Garbincius, Physics Section and Leila Belkora, Office of Public Affaris CROSS SECTION November 1, 1996 By Doreen Wackeroth, Theoretical Physics Edited by Leila Belkora, Office of Public Affaris MAGNETS PART I November 15, 1996 By Hank Glass, Technical Support Section Edited by Donald Sena, Office of Public Affairs

5

Report on the Fracture Analysis of HfB{sub 2}-SiC and ZrB{sub 2}-SiC Composites  

DOE Green Energy (OSTI)

Hafnium diboride-silicon carbide (HS) and zirconium diboride-silicon carbide (ZS) composites are potential materials for high temperature, thermal shock applications such as for components on re-entry vehicles. In order to establish material constants necessary for evaluation of in situ fracture, bars fractured in four-point flexure were examined using fractographic principles. The fracture toughness was determined from measurements of the critical crack sizes and the strength values and the crack branching constants were established to use in forensic fractography for future in-flight tests. The fracture toughnesses range from about 13 MPam{sup 1/2} at room temperature to about 6 MPam{sup 1/2} at 1400 C for ZrB{sub 2}-Sic composites and from about 13 MPam{sup 1/2} at room temperature to about 4 MPam{sup 1/2} at 1400 C for HfB{sub 2}-SiC composites. Thus, the toughnesses of either the HS or ZS composites have the potential for use in thermal shock applications. Processing and manufacturing defects limited the strength of the test bars. However, examination of the microstructure on the fracture surfaces shows that the processing of these composites can be improved. There is potential for high toughness composites with high strength to be used in thermal shock conditions if the processing and handling are controlled.

MECHOLSKY, JR. JOHN J.

2001-09-01T23:59:59.000Z

6

Determining Relative f and d Orbital Contributions to M?Cl Covalency in MCl62– (M = Ti, Zr, Hf, U) and UOCl5 Using Cl K-Edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory  

SciTech Connect

Chlorine K-edge X-ray absorption spectroscopy (XAS) and ground-state and time-dependent hybrid density functional theory (DFT) were used to probe electronic structure for O{sub h}-MCl{sub 6}{sup 2-}(M = Ti, Zr, Hf, U) and C{sub 4v}-UOCl{sub 5}{sup -}, and to determine the relative contributions of valence 3d, 4d, 5d, 6d, and 5f orbitals in M-Cl bonding. Spectral interpretations were guided by time-dependent DFT calculated transition energies and oscillator strengths, which agree well with the experimental XAS spectra. The data provide new spectroscopic evidence for the involvement of both 5f and 6d orbitals in actinide-ligand bonding in UCl{sub 6}{sup 2-}. For the MCl{sub 6}{sup 2-}, where transitions into d orbitals of t{sub 2g} symmetry are spectroscopically resolved for all four complexes, the experimentally determined Cl 3p character per M-Cl bond increases from 8.3(4)% (TiCl{sub 6}{sup 2-}) to 10.3(5)% (ZrCl{sub 6}{sup 2-}), 12(1)% (HfCl{sub 6}{sup 2-}), and 26 18(1)% (UCl{sub 6}{sup 2-}). Chlorine K-edge XAS spectra of UOCl{sub 5}{sup -} provide additional insights into the transition assignments by 27 lowering the symmetry to C{sub 4v}, where five pre-edge transitions into both 5f and 6d orbitals are observed. For UCl{sub 6}{sup 2-}, the XAS data 28 suggest that orbital mixing associated with the U 5f orbitals is considerably lower than that of the U 6d orbitals. For both UCl{sub 6}{sup 2-}29 and UOCl{sub 5}{sup -}, the ground-state DFT calculations predict a larger 5f contribution to bonding than is determined experimentally. 30 These findings are discussed in the context of conventional theories of covalent bonding for d- and f-block metal complexes.

Minasian, Stefan G.; Keith, Jason M.; Batista, Enrique R.; Boland, Kevin S.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Schwarz, Daniel E.; Shuh, David K.; Wagner, Gregory L.; Wilkerson, Marianne P.; Wolfsberg, Laura E.; Yang, Ping

2012-03-09T23:59:59.000Z

7

BeginPackage "rfPack`" Modified 28 Jul 1999  

E-Print Network (OSTI)

voltage vRF, stable phase angle £ in units of 2¥ , and wavelength ¤ ." bucketHF::usage ¡ "bucketHF ¢ ,h compaction ¢ , an RF system with harmonic number h, peak voltage vRF, and stable phase angle £ in units of 2 with harmonic number h, peak voltage vRF, and stable phase angle £ in units of 2¥ , for particles of energy E

Keil, Eberhard

8

Hf-Ir (Hafnium - Iridium)  

Science Conference Proceedings (OSTI)

Hf-Ir crystallographic data...Hf-Ir crystallographic data Phase Composition, wt% Ir Pearson symbol Space group (βHf) 0 to ~10.5 cI 2 Im m (αHf) 0 to ~1.5 hP 2 P 6 3 / mmc Hf 2 Ir ~28 to 35.0 cF 96 Fd m Hf 5 Ir 3 39.3 hP 16 P 6 3 / mcm HfIr 51.9 to 59 o ** � HfIr 3 76 to 82 cP 4 Pm m (Ir) ~91 to 100 cF 4 Fm m...

9

RF transformer  

DOE Patents (OSTI)

There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

Smith, James L. (Naperville, IL); Helenberg, Harold W. (Calumet City, IL); Kilsdonk, Dennis J. (Joliet, IL)

1979-01-01T23:59:59.000Z

10

rf_shield.PDF  

NLE Websites -- All DOE Office Websites (Extended Search)

April 2001 Interaction Region RF Shield Issues G. Stupakov and T.O. Raubenheimer Stanford Linear Accelerator Center Stanford, California 102300 Interaction Region RF Shield...

11

Nonstoichiometry in inorganic fluorides: I. Nonstoichiometry in MF{sub m}-RF{sub n} (m < n {<=} 4) systems  

Science Conference Proceedings (OSTI)

The manifestation of gross nonstoichiometry in MF{sub m}-RF{sub n} systems (m Fluorides of 34 elements, in the systems of which phases of practical interest are formed, are chosen. To search for new phases of complex composition, a program for studying the phase diagrams of the condensed state ({approx}200 systems) has been carried out at the Institute of Crystallography, Russian Academy of Sciences. The main products of high-temperature interactions of the fluorides of elements with different valences (m {ne} n) are grossly nonstoichiometric phases of two structural types: fluorite (CaF{sub 2}) and tysonite (LaF{sub 3}). Systems of fluorides of 27 elements (M{sup 1+} = Na, K; M{sup 2+} = Ca, Sr, Ba, Cd, Pb; R{sup 3+} = Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; R{sup 4+} = Zr, Hf, Th, U) are selected; nonstoichiometric M{sub 1-x}R{sub x}F{sub m(1-x)+nx} phases, which are of greatest practical interest, are formed in these systems. The gross nonstoichiometry in inorganic fluorides is most pronounced in 80 MF{sub 2} - RF{sub 3} systems (M = Ca, Sr, Ba, Cd, Pb; R are rare earth elements). The problems related to the growth of single crystals of nonstoichiometric phases and basic fields of their application as new fluoride multicomponent materials, the properties of which are controlled by the defect structure, are considered.

Sobolev, B. P., E-mail: sobolevb@yandex.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2012-05-15T23:59:59.000Z

12

Growth, microstructure and electrical properties of sputter-deposited hafnium oxide (HfO2) thin films grown using HfO2 ceramic target  

Science Conference Proceedings (OSTI)

Hafnium oxide (HfO?) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(100) substrates under varying growth temperature (Ts). HfO? ceramic target has been employed for sputtering while varying the Ts from room temperature to 500?C during deposition. The effect of Ts on the growth and microstructure of deposited HfO? films has been studied using grazing incidence x-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectrometry (EDS). The results indicate that the effect of Ts is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO? films. Structural characterization indicates that the HfO? films grown at Ts200 ?C are nanocrystalline. An amorphous-to-crystalline transition occurs at Ts=200 ?C. Nanocrystalline HfO? films crystallized in a monoclinic structure with a (-111) orientation. XPS measurements indicated the high surface-chemical quality and stoichiometric nature of the grown HfO? films. An interface layer (IL) formation occurs due to reaction at the HfO?-Si interface for HfO? films deposited at Ts>200 ?C. The thickness of IL increases with increasing Ts. XPS and EDS at the HfO?-Si cross-section indicate the IL is a (Hf, Si)-O compound. The electrical characterization using capacitance-voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing Ts.

Aguirre, B.; Vemuri, R. S.; Zubia, David; Engelhard, Mark H.; Shutthanandan, V.; Kamala Bharathi, K.; Ramana, Chintalapalle V.

2011-01-01T23:59:59.000Z

13

Rf Feedback free electron laser  

DOE Patents (OSTI)

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.

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

14

Rf feedback free electron laser  

DOE Patents (OSTI)

A free electron laser system and electron beam system for a free electron laser are provided 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.

Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-11-02T23:59:59.000Z

15

Radiolysis with RF Photoinjectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiolysis with RF Photoinjectors: Supercritical Xenon Chemistry James F. Wishart in "Femtosecond Beam Science" Uesaka, M., Ed.; Imperial College Press, London, in press. (ISBN...

16

Ni-Zr (Nickel - Zirconium)  

Science Conference Proceedings (OSTI)

Ni-Zr crystallographic data...99.9 to 100 hP 2 P 6 3 / mmc (a) Triclinic. (b) Stoichiometric. (c) Zr-rich...

17

Ga-Zr (Gallium - Zirconium)  

Science Conference Proceedings (OSTI)

Ga-Zr crystallographic data...Ga 5 Zr 3 44.0 oC 32 Cmcm Ga 3 Zr 2 47 oF 40 Fdd 2 βGaZr 56.7 � � αGaZr 56.7 tI 16 I 4 1 / amd Ga 4 Zr 5 62.1 hP 18 P 6 3 / mcm Ga 2 Zr 3 66 tP 10 P 4/ mbm Ga 3 Zr 5 68.6 hP 16 P 6 3 / mcm GaZr 2 72.4 tI 12 I 4/ mcm (βZr) ~94 to 100 cI 2 Im m (αZr) 99.4 to 100 hP 2 P 6 3 / mmc...

18

Phase stable rf transport system  

DOE Patents (OSTI)

This invention is comprised of an RF transport system which 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.

Curtin, M.T.; Natter, E.F.; Denney, P.M.

1991-02-19T23:59:59.000Z

19

Phase stable RF transport system  

DOE Patents (OSTI)

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.

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

1992-01-01T23:59:59.000Z

20

Al-Zr (Aluminum - Zirconium)  

Science Conference Proceedings (OSTI)

Al-Zr crystallographic data...6 3 / mcm ZrAl 22.8 oC 8 Cmcm Zr 2 Al 3 31 oF 40 Fdd 2 ZrAl 2 37.2 hP 12 P 6 3 / mmc ZrAl 3 47 tI 16 I 4/ mmm (Al) 99.86 to 100 cF 4 Fm m...

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

ISG8-RF Sources  

NLE Websites -- All DOE Office Websites (Extended Search)

RF Sources - (WG3) RF Sources - (WG3) Orange Rm Yong Ho Chin, Christopher Nantista, and Sami G. Tantawi Parallel Sessions: Working Groups: WG1: Parameters, Design, Instrumentation and Tuning WG2: Damping Rings and ATF WG3: RF Sources WG4:Structures WG5: Ground Motion; Site Requirements and Investigations Monday Morning 9:00-10:30 Plenary Coffee Break 11:00-12:00 Planning Session. Monday Afternoon 13:30-15:30 High Gradient Issues (Joint with working group 4) Coffee Break 16:00-16:30 The 8-Pack Project -- D. Atkinson 16:30-17:30 High Gradient Issues and Discussions Continued. Tuesday Morning 9:30-10:30 Klystrons 9:30-10:00 Status of PPM Klystron Development for JLC -- Y. H. Chin 10:00-10:30 Design of 150MW Multi-Beam Klystron -- S. Matsumoto Coffee Break 11:00-11:30 Klystron Development at SLAC -- G. Caryotakis

22

Rf2a and rf2b transcription factors  

DOE Patents (OSTI)

A method of activating the rice tungro bacilliform virus (RTBV) promoter in vivo is disclosed. The RTBV promoter is activated by exposure to at least one protein selected from the group consisting of Rf2a and Rf2b.

Beachy, Roger N. (St. Louis, MO); Petruccelli, Silvana (La Plata, AR); Dai, Shunhong (St. Louis, MO)

2007-10-02T23:59:59.000Z

23

Morphology and properties of sputtered HfN layers as a function of substrate temperature and sputtering atmosphere  

SciTech Connect

HfN layers were prepared by reactive rf-magnetron sputtering onto polished flat high speed steel (HSS) surfaces. Rectangular samples were mounted on a special holder providing temperatures in the range of 775 to 300 K along the length of the sample. The HfN layers were deposited at various total pressures and different N/sub 2//Ar ratios. The film morphology and composition was studied by scanning electron microscopy (SEM) and Auger electron spectroscopy (AES), respectively, and correlated with mechanical properties like microhardness and adhesion. The results are discussed with respect to the sputtering conditions.

Jehn, H.A.; Kopacz, U.; Hofmann, S.

1985-11-01T23:59:59.000Z

24

Rf heating of mirrors  

SciTech Connect

A brief overview is presented of potential uses for rf heating of plasmas in mirror devices. While some discussion relating to past experiments is given, the main emphasis is devoted to a review of potential experiments in presently existing devices, and devices under construction or planning. Some predictions are made for plasmas in mirror reactors.

Porkolab, M.

1980-04-09T23:59:59.000Z

25

Eccentric rf deflecting structure  

SciTech Connect

For superconducting rf separators, assembled by electron beam welding techniques, two types of mode stabilizers are discussed: the elliptical structure, and a new design called the eccentric structure''. For an operating pi /2 or pi mode in the lower pass band, it is shown that the various parameters of the eccentric structure can be adjusted to provide the required frequency spacing between the operating mode and the upper dispersion curve. (auth)

Aggus, J.R.; Giordano, S.; Halama, H.J.

1973-12-13T23:59:59.000Z

26

RF current sensor  

DOE Patents (OSTI)

An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Moore, James A. (Powell, TN); Sparks, Dennis O. (Maryville, TN)

1998-11-10T23:59:59.000Z

27

Skin Effect of Hf-Rich Melts and Some Aspects in its Usage for Hf ...  

Science Conference Proceedings (OSTI)

USAGE FOR Hf-CONTAINING. CAST NICKEL- ... of advanced gas turbines. ... were polished by metallo- graphy and then melted by tungsten inert gas(TIG).

28

NSLS-II RF SYSTEMS  

Science Conference Proceedings (OSTI)

The NSLS-II is a new third generation light source being constructed at Brookhaven Lab. The storage ring is optimized for low emittance by use of damping wigglers to reduce the emittance to below 1 nm-rad. The RF systems are designed to provide stable beam through tight RF phase and amplitude stability requirements.

Rose, J.; Gash, W.; Holub, B.; Kawashima, Y.; Ma, H.; Towne, N.; Yeddulla, M.

2011-03-28T23:59:59.000Z

29

MSTC - Microsystems Science, Technology, and Components - RF...  

NLE Websites -- All DOE Office Websites (Extended Search)

capability for the unique demands of National Security. Communications RF MEMS Passive wireless sensorsRFIDsTags RF system minaturization For additional information or...

30

Spectroscopy of {sup 257}Rf.  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {micro}s, was discovered by detecting internal conversion electrons followed by decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF} = 0.02 {+-} 0.01.

Qian, J.; Heinz, A.; Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Asai, M.; Back, B. B.; Carpenter, M. P.; Garnsworthy, A. B.; Greene, J. P.; Hecht, A. A.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X.; Winkler, R.; Zhu, S.; Yale Univ.; Japan Atomic Energy Agency; Univ. of Surrey; Univ. of Maryland

2009-06-01T23:59:59.000Z

31

Spectroscopy of {sup 257}Rf  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on {alpha} hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by {alpha} decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF}=0.02{+-}0.01.

Qian, J.; Heinz, A.; Winkler, R. [WNSL, Yale University, New Haven, Connecticut 06511 (United States); Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X. [Argonne National Laboratory, Illinois 60439 (United States)] (and others)

2009-06-15T23:59:59.000Z

32

Pu-Zr (Plutonium - Zirconium)  

Science Conference Proceedings (OSTI)

Pu-Zr crystallographic data...0 to 100 cI 2 Im m (δ�Pu) 0 to 0.76 tI 2 I 4/ mmm (δPu) 0 to 47 cF 4 Fm m (γPu) 0 to 1.1 oF 8 Fddd (βPu) 0 to 2.7 mC 34 C 2/ m (αPu) 0 to 0.57 mP 16 P 2 1 / m θ (or Pu 4 Zr) 4 to 14 tP 80 P 4/ ncc κ (or PuZr 3 ) 52 hP 3 P 6/ mmm (αZr) 71 to 100 hP 2 P 6 3 / mmm...

33

Removal of uranium from aqueous HF solutions  

DOE Patents (OSTI)

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.

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

1980-01-01T23:59:59.000Z

34

Removal of uranium from aqueous HF solutions  

Science Conference Proceedings (OSTI)

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 separating the solution from the settled particulates. The CaF2 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.

Pulley, H.; Seltzer, S.F.

1980-11-18T23:59:59.000Z

35

Booster Subharmonic RF Capture Design  

NLE Websites -- All DOE Office Websites (Extended Search)

require a < (1 40 ns) 25 MHz subharmonic frequency. Due to the difficulty of building high-voltage low-frequency rf cavities, this requirement can be relaxed so that at least...

36

Pushing the Limits of RF Superconductivity Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Presentations Workshop Proceedings Suggested Reading Material on RF Superconductivity Workshop Dinner Accommodations Ground Transportation Access to...

37

Molten Salt Electrorefining of Zr-Hf Impure Metal for Nuclear ...  

Science Conference Proceedings (OSTI)

A21: First-Principles Molecular Dynamics Simulation of Chemical ... A3: Investigation on Co-combustion Kinetics of Anthracite Coal and Biomass Char by ... Lithium Redox Process for Thermochemical Water-Splitting as Energy Conversion.

38

RF & Microwave Systems Group The RF & Microwave Systems  

E-Print Network (OSTI)

for Technology Transfer. Tagging, Tracking, and Locating Systems TTL technologies are on the verge and development (R&D) geared toward supplying robust communications for extreme environments; global tagging, tracking, and locating (TTL) systems; and RF- and microwave- based measurement and processing systems

39

Simulation of synchrotron motion with rf noise  

Science Conference Proceedings (OSTI)

The theoretical formulation is described that is behind an algorithm for synchrotron phase-space tracking with rf noise and some preliminary simulation results of bunch diffusion under rf noise obtained by actual tracking.

Leemann, B.T.; Forest, E.; Chattopadhyay, S.

1986-08-01T23:59:59.000Z

40

MSTC - Microsystems Science, Technology, and Components - RF...  

NLE Websites -- All DOE Office Websites (Extended Search)

band RF input and supplies N identical outputs (N4 or 8). SiGe, GaAs, GaN RFICs. Passive RF detectors - Pyroelectric microdetectors that produce a DC output proportional to...

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

High-Power Rf Load  

DOE Patents (OSTI)

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.

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

1998-09-01T23:59:59.000Z

42

Modulation instability in RF MEMS devices  

Science Conference Proceedings (OSTI)

Modulation instability generated by mechanical frequencies in RF MEMS switches is predicted and its potential contribution to the RF signal degradation is discussed. In particular, evaluations have been performed for double clamped configurations in ... Keywords: Modulation instability, Nonlinear Schrodinger equation, Power handling, RF MEMS

Romolo Marcelli; Giancarlo Bartolucci; Giorgio Angelis; Andrea Lucibello; Emanuela Proietti

2012-04-01T23:59:59.000Z

43

Increased Energy Efficiency and Reduced HF Emissions with New ...  

Science Conference Proceedings (OSTI)

Presentation Title, Increased Energy Efficiency and Reduced HF Emissions with New Heat Exchanger. Author(s), Anders Kenneth Sorhuus, Geir Wedde, Ketil A.

44

Low jitter RF distribution system  

SciTech Connect

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.

Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

2012-09-18T23:59:59.000Z

45

Rf System for the NLCTA  

Science Conference Proceedings (OSTI)

This paper describes an X-Band RF system for the Next Linear Collider Test Accelerator. The RF system consists of a 90 MeV injector and a 540 MeV linac. The main components of the injector are two low-Q single-cavity prebunchers and two 0.9-m-long detuned accelerator sections. The linac system consists of six 1.8-m-long detuned and damped detuned accelerator sections powered in pairs. The rf power generation, compression, delivery, distribution and measurement systems consist of klystrons, SLEDII energy compression systems, rectangular waveguides, magic-T's, and directional couplers. The phase and amplitude for each prebuncher is adjusted via a magic-T type phase shifter/attenuator. Correct phasing between the two 0.9 m accelerator sections is obtained by properly aligning the sections and adjusting two squeeze type phase shifters. Bunch phase and bunch length can be monitored with special microwave cavities and measurement systems. The design, fabrication, microwave measurement, calibration, and operation of the sub-systems and their components are briefly presented.

Wang, J.W.; /SLAC; Adolphsen, C.; Eichner, J.; Fuller, R.W.; Gold, S.L.; Hanna, S.M.; Hoag, H.A.; Holmes, S.G.; Koontz, R.F.; Lavine, Theodore L.; Loewen, R.J.; Miller, R.H.; Nantista, C.D.; Pope, R.; Rifkin, J.; Ruth, R.D.; Tantawi, S.G.; Vlieks, A.E.; Wilson, Z.; Yeremian, A.; /SLAC

2011-08-26T23:59:59.000Z

46

Band offsets in ZrO{sub 2}/InGaZnO{sub 4} heterojunction  

SciTech Connect

X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band ( White-Up-Pointing-Triangle E{sub V}) of amorphous InGaZnO{sub 4} (a-IGZO)/ZrO{sub 2} heterostructure deposited by DC and RF sputtering at room temperature, respectively. A value of White-Up-Pointing-Triangle E{sub V}= 0 eV was obtained by using the Ga and Zn 2p{sup 3} and In 3d{sup 3} energy levels as references. Given the experimental band gap of 3.1 eV and 5.8 eV for the a-IGZO and ZrO{sub 2}, respectively, this would indicate a conduction band offset of 2.7 eV in the system.

Yao Jianke [School of Computer and Information Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Zhang Shengdong [School of Computer and Information Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Institute of Microelectronics, Peking University, Beijing 100871 (China); Gong Li [Instrumental Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275 (China)

2012-08-27T23:59:59.000Z

47

On the dynamic NBTI of the HfO2 and HfSiON P-MOSFET  

Science Conference Proceedings (OSTI)

Under typical dynamic NBTI conditions (~7MV/cm, 100^oC), a progressive decrease in the recoverable component (R) of the HfO"2 p-MOSFET is observed but those of the HfSiON and SiON p-MOSFETs are found to remain constant. The decrease in the R of the HfO"2 ... Keywords: Bias-temperature instability, Hole trapping, Interface traps, Permanent degradation, Recovery

Y. Gao; D. S. Ang; A. A. Boo; Z. Q. Teo

2011-07-01T23:59:59.000Z

48

Single electron beam rf feedback free electron laser  

DOE Patents (OSTI)

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.

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

1981-02-11T23:59:59.000Z

49

Overview of the RF Systems for LCLS  

SciTech Connect

The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time [1]. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and peak current phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these tight constraints.

McIntosh, P.; Akre, R.; Boyce, R.; Emma, P.; Hill, A.; Rago, C.; /SLAC

2005-06-15T23:59:59.000Z

50

Overview of the RF Systems for LCLS  

E-Print Network (OSTI)

The Linac Coherent Light Source (LCLS) at SLAC, when it becomes operational in 2009, will provide its user community with an X-ray source many orders of magnitude brighter than anything available in the world at that time. The electron beam acceleration will be provided by existing and new RF systems capable of maintaining the amplitude and phase stability of each bunch to extremely tight tolerances. RF feedback control of the various RF systems will be fundamental in ensuring the beam arrives at the LCLS undulator at precisely the required energy and phase. This paper details the requirements for RF stability for the various LCLS RF systems and also highlights proposals for how these injector and Linac RF systems can meet these constraints.

McIntosh, Peter; Boyce, Richard; Emma, Paul; Hill, Alan; Rago, Carl

2005-01-01T23:59:59.000Z

51

Decay Study of {sup 257}Rf  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti, n){sup 257}Rf. Reaction products were separated by the Argonne Fragment Mass Analyzer. Radioactive decay and spontaneous fission of {sup 257}Rf and its decay products were investigated. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup 42} {mu}S, was discovered by detecting internal conversion electrons followed by alpha decays. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal-conversion electrons which were succeeded by alpha decay, with a half-life of 4.1{sub -1.3}{sup +2.4} s, was observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf, or from another isomer in {sup 257}Rf.

Qian, J.; Heinz, A.; Winkler, R. [Yale University, New Haven, CT 06511 (United States); Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.; Peterson, D.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Pardo, R. C.; Robinson, A.; Scott, R.; Vondrasek, R.; Wang, X.; Zhu, S. [Argonne National Laboratory, Argonne, IL 60439 (United States)] (and others)

2009-03-04T23:59:59.000Z

52

High voltage RF feedthrough bushing  

DOE Patents (OSTI)

Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, Glenn F. (Huntington Station, NY)

1984-01-01T23:59:59.000Z

53

Interfacial transition regions at germanium/Hf oxide based dielectric interfaces: Qualitative differences between non-crystalline Hf Si oxynitride and nanocrystalline HfO2 gate stacks  

Science Conference Proceedings (OSTI)

The contribution from a relatively low-K SiON (K~6) interfacial transition region (ITR) between Si and transition metal high-K gate dielectrics such as nanocrystalline HfO"2 (K~20), and non-crystalline Hf Si oxynitride (K~10-12) places a significant ... Keywords: Di-vacancy defects, Ge substrates, High-K gate dielectrics, Interfacial transition regions, MOS devices, Native Ge dielectrics, Spectroscopic ellipsometry, X-ray absorption spectroscopy

G. Lucovsky; S. Lee; J. P. Long; H. Seo; J. Lüning

2009-03-01T23:59:59.000Z

54

A Survey of the Urban RF Environment  

Science Conference Proceedings (OSTI)

The prevalence of sources of radio-frequency (RF) electromagnetic fields is expanding at a rapid pace.  As new wireless technologies are deployed (e.g., smart meters), questions are often raised as to what extent people are exposed to their RF emissions, and what if any effects on health and safety the RF could possibly cause. To obtain a frame of reference for the contributions of new sources to our environment, this study was designed to quantify the levels of RF fields that already exist in ...

2012-12-31T23:59:59.000Z

55

Characteristics of multiantenna rf ion source  

Science Conference Proceedings (OSTI)

We have developed a new multiantenna rf ion source for neutral beam injection and studied the effects of different antennas connected in parallel

T. Shoji; Y. Oka; NBI Group

2006-01-01T23:59:59.000Z

56

Passive RF Components - Microsystems Science, Technology, and...  

NLE Websites -- All DOE Office Websites (Extended Search)

Passive RF Components Microsystems Home Custom Microsystems Solutions Microsystems R&D Services Capabilities and Technologies Facilities Trusted Microsystems General Info About Us...

57

Recent Studies of RF Breakdown Physics in Normal Conducting Cavities  

SciTech Connect

The operating accelerating gradient in normal conducting accelerating structures is often limited by rf breakdown. The behavior of the rf breakdown depends on multiple parameters, including the input rf power, rf circuit, cavity shape and material. Here we discuss recent experimental data and theoretical studies of rf breakdown physics.

Dolgashev, Valery; /SLAC

2012-06-11T23:59:59.000Z

58

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

E-Print Network (OSTI)

(PV) [1]. Oxides of cadmium, indium, and tin with simultaneous visible transparency and relatively) as a result. Indium oxide alloyed with up to ~10 wt.% tin oxide (and called ITO) has been one of the more. Weiss 4 , Bridget R. Rogers 5 1 National Renewable Energy Laboratory, National Center for Photovoltaics

Weiss, Sharon

59

Sunpentown: ENERGY STAR Referral (RF-330SS) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

ENERGY STAR Referral (RF-330SS) Sunpentown: ENERGY STAR Referral (RF-330SS) May 10, 2013 DOE referred the matter of Sunpentown-brand refrigerator, model RF-330SS, manufactured by...

60

Samsung: ENERGY STAR Referral (RF26VAB) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Samsung: ENERGY STAR Referral (RF26VAB) Samsung: ENERGY STAR Referral (RF26VAB) March 16, 2010 DOE referred the matter of Samsung refrigerator-freezer model RF26VAB to the U.S....

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

R&D ERL: Low level RF  

SciTech Connect

A superconducting RF (SRF) Energy Recovery Linac (ERL) is currently under development at the Collider-Accelerator Department (C-AD) at Brookhaven National Laboratory (BNL). The major components from an RF perspective are (a) a 5-cell SRF ERL cavity, (b) an SRF photocathode electron gun, and (c) a drive laser for the photocathode gun. Each of these RF subsystems has its own set of RF performance requirements, as well as common requirements for ensuring correct synchronism between them. A low level RF (LLRF) control system is currently under development, which seeks to leverage both technology and experience gained from the recently commissioned RHIC LLRF system upgrade. This note will review the LLRF system requirements and describe the system to be installed at the ERL.

Smith, K.

2010-01-15T23:59:59.000Z

62

Linear Gain for the Microbunching Instability in an RF Compressor  

E-Print Network (OSTI)

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

Venturini, M.

2010-01-01T23:59:59.000Z

63

Theoretical Assessment of 178m2Hf De-Excitation  

Science Conference Proceedings (OSTI)

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.

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

64

Factors Affecting the Accuracy of SHOWEX HF Radar Wave Measurements  

Science Conference Proceedings (OSTI)

Ocean Surface Current Radar (OSCR) HF radar measurements of ocean waves and currents were made during the Shoaling Waves Experiment (SHOWEX) in the fall of 1999. During some periods, at some locations, good quality wave measurements were ...

Lucy R. Wyatt; Guennadi Liakhovetski; Hans C. Graber; Brian K. Haus

2005-07-01T23:59:59.000Z

65

Spatial Averaging of HF Radar Data for Wave Measurement Applications  

Science Conference Proceedings (OSTI)

HF radar data are often collected for time periods that are optimised for current measurement applications where, in many cases, very high temporal resolution is needed. Previous work has demonstrated that this does not provide sufficient ...

Lucy R. Wyatt; Jasmine B. D. Jaffrés; Mal L. Heron

66

DENSITY-FUNCTIONAL STUDY OF Zr-BASED ACTINIDE ALLOYS: 2. U-Pu-Zr SYSTEM  

Science Conference Proceedings (OSTI)

Density-functional theory, previously used to describe phase equilibria in the U-Zr alloys [1], is applied to study ground state properties of the bcc U-Pu-Zr solid solutions. Calculated heats of formation of the Pu-U and Pu-Zr alloys are in a good agreement with CALPHAD assessments. We found that account for spin-orbit coupling is important for successful description of Pu-containing alloys.

Landa, A; Soderlind, P; Turchi, P; Vitos, L; Ruban, A

2009-02-09T23:59:59.000Z

67

Matching network for RF plasma source  

DOE Patents (OSTI)

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.

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

2007-11-20T23:59:59.000Z

68

Review of the APS SR RF systems.  

DOE Green Energy (OSTI)

The Advanced Photon Source (APS) is a 7-GeV full energy storage ring (SR) for generating synchrotron radiation with an injector. The storage ring cavities consist of four groups of four single cells powered by up to four 1-MW klystrons for up to 300-mA operation. A review of the operation of the rf system as well as rf-related beam dynamics is presented. This review includes rf power distribution, low-level feedback, control law, beam loading, beam instabilities, higher-order modes, and beam-induced multipactoring.

Song, J.J.; Cours, A.; Grelick, A.; Harkay, K.; Horan, D.; Kang, Y.W.; Kustom, R.L.; Nassiri, A.; Pile, G.; Smith, T.L.

1998-03-31T23:59:59.000Z

69

Nuclear Fuels & Zr-alloy Claddings  

Science Conference Proceedings (OSTI)

Mar 7, 2013 ... Microstructural Processes in Irradiated Materials: Nuclear Fuels & Zr-alloy ... Center for Materials Science of Nuclear Fuels, an Energy Frontier Research ... However, more recently density functional theory calculations have ...

70

Degreasing and cleaning superconducting RF Niobium cavities  

Science Conference Proceedings (OSTI)

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.

Rauchmiller, Michael; Kellett, Ron; /Fermilab

2011-09-01T23:59:59.000Z

71

RF Micro Devices | Open Energy Information  

Open Energy Info (EERE)

National Center for Photovoltaics Partnership Year 2009 LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now RF Micro Devices is a company located in...

72

SLAC Linac RF Performance for LCLS *  

E-Print Network (OSTI)

The Linac Coherent Light Source (LCLS) project at SLAC uses a dense 15 GeV electron beam passing through a long undulator to generate extremely bright x-rays at 1.5 angstroms. The project requires electron bunches with a nominal peak current of 3.5kA and bunch lengths of 0.020mm (70fs). The bunch compression techniques used to achieve the high brightness impose challenging tolerances on the accelerator RF phase and amplitude. The results of measurements on the existing SLAC linac RF phase and amplitude stability are summarised and improvements needed to meet the LCLS tolerances are discussed. 1 LCLS RF REQUIREMENTS LCLS requires the SLAC linac to perform with tolerances on RF phase and amplitude stability which are beyond all previous requirements. The LCLS is divided into four linacs L0, L1, L2, and L3 [1]. The phase and amplitude tolerances for the four linacs operated at S-

unknown authors

2000-01-01T23:59:59.000Z

73

Deeply scaled CMOS for RF power applications  

E-Print Network (OSTI)

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 ...

Scholvin, Jörg, 1976-

2006-01-01T23:59:59.000Z

74

Vortex formation during rf heating of plasma  

SciTech Connect

Experiments on a test plasma show that the linear theory of waveguide coupling to slow plasma waves begins to break down if the rf power flux exceeds approx. 30 W/cm/sup 2/. Probe measurements reveal that within 30 ..mu..s an undulation appears in the surface plasma near the mouth of the twin waveguide. This surface readjustment is part of a vortex, or off-center convective cell, driven by asymmetric rf heating of the plasma column.

Motley, R.W.

1980-05-01T23:59:59.000Z

75

High Power RF Sources for Accelerators  

SciTech Connect

This presentation describes RF sources developed and under development at Calabazas Creek Research, Inc. for driving high power accelerators and colliders. The RF sources range from L-Band to W-Band and power levels from 10s of kilowatts CW to 200 MW pulsed. The configurations include standard klystrons, multiple beam klystrons, sheet beam devices, and gyroklystrons. The basic parameters are presented with a basic description of operation and applications.

Ives, Lawrence; Read, Michael; Neilson, Jeff; Borchard, Philipp; Mizuhara, Max [Calabazas Creek Research, Inc., 690 Port Drive, San Mateo, CA 94404 (United States); Lawson, Wesley [Insitute for Research in Applied Physics, University of Maryland, College Park, MD 20742 (United States)

2006-11-27T23:59:59.000Z

76

Status of the ADMX and ADMX-HF experiments  

E-Print Network (OSTI)

The Axion Dark Matter eXperiment (ADMX) is in the midst of an upgrade to reduce its system noise temperature. ADMX-HF (High Frequency) is a second platform specifically designed for higher mass axions and will serve as an innovation test-bed. Both will be commissioning in 2013 and taking data shortly thereafter. The principle of the experiment, current experimental limits and the status of the ADMX/ADMX-HF program will be described. R&D on hybrid superconducting cavities will be discussed as one example of an innovation to greatly enhance sensitivity.

Karl van Bibber; Gianpaolo Carosi

2013-04-29T23:59:59.000Z

77

(U,Zr)N alloy having enhanced thermal stability  

DOE Patents (OSTI)

A nitrided alloy of uranium and zirconium is provided which consists of a single-phase UN structure containing a dissolved amount of Zr as ZrN, effective to inhibit dissociation of the UN phase.

Potter, Ralph A. (Lynchburg, VA); Scott, James L. (Knoxville, TN)

1977-01-01T23:59:59.000Z

78

Prospects for Advanced RF Theory and Modeling  

SciTech Connect

This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed.

Batchelor, D.B.

1999-04-12T23:59:59.000Z

79

Hf-Doped Ni-Al2O3 Interfaces at Equilibrium  

SciTech Connect

In this study, a series of dewetting experiments of pure and Hf-doped Ni films on sapphire and HfO2 substrates were conducted in order to measure the change in interface energy of the Ni-Al2O3 interface in the presence of Hf, and to study Hf interfacial segregation. It was found that Hf oxidizes under the conditions of the experiment (P(O2)=10-20atm.), and that the presence of HfO2 at the Ni-Al2O3 interface increases the interface energy from 2.16 0.2 to 2.7 0.4 [J/m2]. This result contradicts several theoretical studies that predict that Hf segregates to the interface to stabilize it thermodynamically. The solubility of Hf in bulk Ni was found to be significantly lower than the value reported in the equilibrium phase diagram.

Meltzman, Hila [Technion, Israel Institute of Technology; Besmann, Theodore M [ORNL; Kaplan, Prof. Wayne D. [Technion, Israel Institute of Technology

2012-01-01T23:59:59.000Z

80

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

Science Conference Proceedings (OSTI)

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.

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

2012-12-21T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Chemical and nuclear properties of Rutherfordium (Element 104)  

Science Conference Proceedings (OSTI)

The chemical-properties of rutherfordium (Rf) and its group 4 homologs were studied by sorption on glass support surfaces coated with cobalt(II)ferrocyanide and by solvent extraction with tributylphosphate (TBP) and triisooctylamine (TIOA). The surface studies showed that the hydrolysis trend in the group 4 elements and the pseudogroup 4 element, lb, decreases in the order Rf>Zr{approx}Hf>Th. This trend was attributed to relativistic effects which predicted that Rf would be more prone to having a coordination number of 6 than 8 in most aqueous solutions due to a destabilization of the 6d{sub 5/2} shell and a stabilization of the 7p{sub l/2} shell. This hydrolysis trend was confirmed in the TBP/HBr solvent extraction studies which showed that the extraction trend decreased in the order Zr>Hf>Rf?Ti for HBr, showing that Rf and Ti did not extract as well because they hydrolyzed more easily than Zr and Hf. The TIOA/HF solvent extraction studies showed that the extraction trend for the group 4 elements decreased in the order Ti>Zr{approx}Hf>Rf, in inverse order from the trend of ionic radii Rf>Zr{approx}Hf>Ti. An attempt was made to produce {sup 263}Rf (a) via the {sup 248}Cm({sup 22}Ne, {alpha}3n) reaction employing thenoyltrifluoroacetone (TTA) solvent extraction chemistry and (b) via the {sup 249}Bk({sup 18}O,4n) reaction employing the Automated Rapid Chemistry Apparatus (ARCA). In the TTA studies, 16 fissions were observed but were all attributed to {sup 256}Fm. No alpha events were observed in the Rf chemical fraction. A 0.2 nb upper limit production cross section for the {sup 248}Cm({sup 22}Ne, {alpha}3n){sup 263}Rf reaction was calculated assuming the 500-sec half-life reported previously by Czerwinski et al. [CZE92A].

Kacher, C.D.

1995-10-30T23:59:59.000Z

82

Effect of Al addition on the microstructure and electronic structure of HfO2 film  

E-Print Network (OSTI)

Effect of Al addition on the microstructure and electronic structure of HfO2 film X. F. Wang investigated the microstructures and electronic structures of a series of hafnium aluminate HfAlO films with Al concentration ranging from 0% to 100%. When the films evolve from pure HfO2 to pure Al2O3 by increasing

Gong, Xingao

83

Tubular RF cage field confinement cavity - Energy Innovation ...  

An RF cavity is provided with a plurality of tubes that are formed into a tubular cage in a predefined shape to define the RF cavity. A selected number of tubes and a ...

84

Klystron "efficiency loop" for the ALS storage ring RF system  

E-Print Network (OSTI)

EFFICIENCY LOOP” FOR THE ALS STORAGE RING RF SYSTEM* S.at the Advanced Light Source (ALS) in order to decrease thethe cavities. 1 INTRODUCTION ALS Storage Ring RF system is

Kwiatkowski, Slawomir; Julian, Jim; Baptiste, Kenneth

2002-01-01T23:59:59.000Z

85

Transient beam loading in the ALS harmonic RF system  

E-Print Network (OSTI)

TRANSIENT BEAM LOADING IN THE ALS HARMONIC RF SYSTEM * J.as the Advanced Light Source (ALS), with moderately low beamharmonic RF system on the ALS storage ring consisting of 5

2000-01-01T23:59:59.000Z

86

Eccentric superconducting RF cavity separator structure  

DOE Patents (OSTI)

Accelerator apparatus having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects.

Aggus, John R. (Shoreham, NY); Giordano, Salvatore T. (Port Jefferson, NY); Halama, Henry J. (Shoreham, NY)

1976-01-01T23:59:59.000Z

87

RF Breakdown of Metallic Surfaces in Hydrogen  

DOE Green Energy (OSTI)

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.

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

88

RF Design of the LCLS Gun  

Science Conference Proceedings (OSTI)

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.

Limborg-Deprey, C

2010-12-13T23:59:59.000Z

89

Cw rf operation of the FMIT RFQ  

SciTech Connect

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.

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

1985-01-01T23:59:59.000Z

90

RUGGED CERAMIC WINDOW FOR RF APPLICATIONS  

Science Conference Proceedings (OSTI)

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.

MIKE NEUBAUER

2012-11-01T23:59:59.000Z

91

Superconducting RF systems for eRHIC  

Science Conference Proceedings (OSTI)

The proposed electron-hadron collider eRHIC will consist of a six-pass 30-GeV electron Energy Recovery Linac (ERL) and one of RHIC storage rings operating with energy up to 250 GeV. The collider design extensively utilizes superconducting RF (SRF) technology in both electron and hadron parts. This paper describes various SRF systems, their requirements and parameters.

Belomestnykh S.; Ben-Zvi, I.; Brutus, J.C.; Hahn, H. et al

2012-05-20T23:59:59.000Z

92

RF Gun Photocathode Research at SLAC  

Science Conference Proceedings (OSTI)

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.

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

93

A thermodynamic description of the Mg-Sm-Zr system  

Science Conference Proceedings (OSTI)

Combining with the thermodynamic parameters of the Sm-Zr binary systems cited from ... phase equilibria are in good agreement with the experimental data.

94

Effect of Thermal Oxidation on the Surface Characteristics of Zr ...  

Science Conference Proceedings (OSTI)

Presentation Title, Effect of Thermal Oxidation on the Surface Characteristics of Zr -based Bulk Metallic Glasses. Author(s), Ka Ram Lim, Won Tae Kim, Do Hyang ...

95

Initial RF measurements of the CW normal-conducting RF injector  

Science Conference Proceedings (OSTI)

The LANL 2.5-cell, normal-conducting radio-frequency (NCRF) injector has been fabricated. We present initial results of low-power RF measurements (cavity Q, cavity field map, coupling beta, etc.) of the NCRF injector. The measured cavity Q and relative fields are found to be in good agreement with the design calculations and earlier measurements of Glidcop properties. However, the coupling beta of the ridge-loaded waveguides is found to be significantly higher than the design point. The impact of these low-power measurement results on the planned high-power RF and electron beam tests will be discussed.

Krawcyk, Frank L [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Martinez, Felix A [Los Alamos National Laboratory; Nguyen, Dinh C [Los Alamos National Laboratory; Bolme, Gerald [Los Alamos National Laboratory; Young, Karen [Los Alamos National Laboratory; Toung, Lloyd [AES

2008-01-01T23:59:59.000Z

96

Realization and modeling of rf superconducting quantum interference device metamaterials  

E-Print Network (OSTI)

We have prepared meta-atoms based on radio frequency superconducting quantum interference devices (RF SQUIDs) and examined their tunability with dc magnetic field, rf current, and temperature. RF SQUIDs are superconducting split ring resonators in which the usual capacitance is supplemented with a Josephson junction, which introduces strong nonlinearity in the rf properties. We find excellent agreement between the data and a model which regards the Josephson junction as the resistively and capacitively-shunted junction. A magnetic field tunability of 80 THz/Gauss at 12 GHz is observed, a total tunability of 56$%$ is achieved, and a unique electromagnetically-induced transparency feature at intermediate excitation powers is demonstrated for the first time. An RF SQUID metamaterial is shown to have qualitatively the same behavior as a single RF SQUID with regards to DC flux and temperature tuning.

M. Trepanier; Daimeng Zhang; Oleg Mukhanov; Steven M. Anlage

2013-08-06T23:59:59.000Z

97

3D surface topography study of the biofunctionalized nanocrystalline Ti-6Zr-4Nb/Ca-P  

Science Conference Proceedings (OSTI)

In this work surface of the sintered Ti-6Zr-4Nb nanocrystalline alloy was electrochemically biofunctionalized. The porous surface was produced by anodic oxidation in 1 M H{sub 3}PO{sub 4} + 2%HF electrolyte at 10 V for 30 min. Next the calcium-phosphate (Ca-P) layer was deposited, onto the formed porous surface, using cathodic potential - 5 V kept for 60 min in 0.042 M Ca(NO{sub 3}){sub 2} + 0.025 M (NH{sub 4}){sub 2}HPO{sub 4} + 0.1 M HCl electrolyte. The deposited Ca-P layer anchored in the pores. The biofunctionalized surface was studied by XRD, SEM and EDS. In vitro tests culture of normal human osteoblast (NHOst) cells showed very good cells proliferation, colonization and multilayering. Using optical profiler, roughness and hybrid 3D surface topography parameters were estimated. Correlation between surface composition, morphology, roughness and biocompatibility results was done. It has been shown by us that surface with appropriate chemical composition and topography, after combined electrochemical anodic and cathodic surface treatment, supports osteoblast adhesion and proliferation. 3D topography measurements using optical profiler play a key role in the biomaterials surface analysis. - Highlights: Black-Right-Pointing-Pointer Nanocrystalline Ti-6Zr-4Nb/Ca-P material was produced for hard tissue implant applications. Black-Right-Pointing-Pointer Calcium-phosphate results in surface biofunctionalization. Black-Right-Pointing-Pointer The biofunctionalized surface shows good in-vitro behavior.

Jakubowicz, J., E-mail: jaroslaw.jakubowicz@put.poznan.pl [Poznan University of Technology, Institute of Materials Science and Engineering, M. Sklodowska-Curie 5 Sq., 60-965 Poznan (Poland); Adamek, G. [Poznan University of Technology, Institute of Materials Science and Engineering, M. Sklodowska-Curie 5 Sq., 60-965 Poznan (Poland); Jurczyk, M.U. [Poznan University of Medical Sciences, Mothers and Childs Health Division, Polna 33, 60-535 Poznan (Poland); Jurczyk, M. [Poznan University of Technology, Institute of Materials Science and Engineering, M. Sklodowska-Curie 5 Sq., 60-965 Poznan (Poland)

2012-08-15T23:59:59.000Z

98

Interfacial Energy Transfer during Gamma Radiolysis of Water on the Surface of ZrO2 and Some Other Oxides  

SciTech Connect

Effect of oxide interface on 60Co gamma radiolysis of water molecules was studied. Based on the molecular hydrogen yield when compared with that from the radiolysis of pure gas-phase water, all tested oxides can be classified into three groups: (i) inhibitors - MnO2, Co3O4, CuO and Fe2O3; (ii) oxides with H2 yields, which are similar to or slightly greater than radiolysis of pure gas-phase water - MgO, CaO, SrO, BaO, ZnO, CdO, Cu2O, NiO, Cr2O3, Al2O3, CeO2, SiO2, TiO2, Nb2O5 and WO3; (iii) promoters - Ga2O3, Y2O3, La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Yb2O3, Er2O3, HfO2, and ZrO2. H2O radiolysis enhancement for ZrO2 and other promoters is result of effective energy transfer at the oxide/water interface, presumably due to migration of excitons to the surface and their resonant coupling with the H2O adsorption complex. Plot''effective H2 yield vs. band-gap (Eg) energy'' shows a maximum near 5 eV.

Petrik, Nikolay G. (BATTELLE (PACIFIC NW LAB)); Alexandrov, Alexandr B. (ASSOC WESTERN UNIVERSITY); Vall, Andrey I. (Institute of Technology)

2000-12-01T23:59:59.000Z

99

Defects and instabilities in Hf-dielectric/SiON stacks (Invited Paper)  

Science Conference Proceedings (OSTI)

In this work, a review on the recent progress in understanding defects and instabilities in Hf-dielectric/SiON stacks will be given for both nMOSFETs and pMOSFETs. The key issues addressed for nMOSFETs include the capture cross section of electron traps, ... Keywords: Defects, Hf-silicates, HfO2, High-k dielectrics, Instability, NBTI, PBTI, Positive charges, Traps

J. F. Zhang

2009-07-01T23:59:59.000Z

100

Shape Memory Response of NiTiHfPd High Strength and High ...  

Science Conference Proceedings (OSTI)

In this study, shape memory and superelastic properties of NiTiHfPd polycrystalline and single crystalline SMAs as functions of aging temperature and time were ...

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101

Development of Continuous SiC Fiber Reinforced HfB 2  

Science Conference Proceedings (OSTI)

Symposium, Ceramic Matrix Composites. Presentation Title, Development of Continuous SiC Fiber Reinforced HfB2-SiC Composites for Aerospace Applications.

102

CLIC RF High Power Production Testing Program  

SciTech Connect

The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation. The testing program overview and test results available to date are presented.

Syratchev, I.; Riddone, G.; /CERN; Tantawi, S.G.; /SLAC

2011-11-02T23:59:59.000Z

103

Accelerator and rf system development for NLC  

Science Conference Proceedings (OSTI)

An experimental station for an X-band Next Linear Collider has been constructed at SLAC. This station consists of a klystron and modulator, a low-loss waveguide system for rf power distribution, a SLED II pulse-compression and peak-power multiplication system, acceleration sections and beam-line components (gun, prebuncher, preaccelerator, focussing elements and spectrometer). An extensive program of experiments to evaluate the performance of all components is underway. The station is described in detail in this paper, and results to date are presented.

Vlieks, A.E.; Callin, R.; Deruyter, H. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

1993-04-01T23:59:59.000Z

104

Available Technologies: High Efficiency Spiral RF-Induction ...  

The spiral antennas efficient use of source geometry also ... Neutron and high energy gamma ... A typical RF-induction plasma generator with a ...

105

Influence of Substrate Temperature and RF Power on the Formation ...  

Science Conference Proceedings (OSTI)

Presentation Title, Influence of Substrate Temperature and RF Power on the Formation of ZnO Nanorods for Solar Driven Hydrogen Production. Author(s) ...

106

Active high-power RF switch and pulse compression system  

DOE Patents (OSTI)

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.

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

1998-01-01T23:59:59.000Z

107

High power RF test of an 805 MHz RF cavity for a muon cooling channel  

SciTech Connect

We present recent high power RF test results on an 805 MHz cavity for a muon cooling experiment at Lab G in Fermilab. In order to achieve high accelerating gradient for large transverse emittance muon beams, the cavity design has adopted a pillbox like shape with 16 cm diameter beam iris covered by thin Be windows, which are demountable to allow for RF tests of different windows. The cavity body is made from copper with stiff stainless steel rings brazed to the cavity body for window attachments. View ports and RF probes are available for visual inspections of the surface of windows and cavity and measurement of the field gradient. Maximum of three thermo-couples can be attached to the windows for monitoring the temperature gradient on the windows caused by RF heating. The cavity was measured to have Q{sub 0} of about 15,000 with copper windows and coupling constant of 1.3 before final assembling. A 12 MW peak power klystron is available at Lab G in Fermilab for the high power test. The cavity and coupler designs were performed using the MAFIA code in the frequency and the time domain. Numerical simulation results and cold test measurements on the cavity and coupler will be presented for comparisons.

Li, Derun; Corlett, J.; MacGill, R.; Rimmer, R.; Wallig, J.; Zisman, M.; Moretti, A.; Qian, Z.; Wu, V.; Summers, D.; Norem, J.

2002-05-30T23:59:59.000Z

108

Low-power/low-voltage RF microsystems for wireless sensors networks  

Science Conference Proceedings (OSTI)

This paper presents radio-frequency (RF) microsystems (MSTs) composed by low-power devices for use in wireless sensors networks (WSNs). The RF CMOS transceiver is the main electronic system and its power consumption is a critical issue. Two RF CMOS transceivers ... Keywords: RF CMOS transceiver, RF microsystems, Wireless sensors networks

J. P. Carmo; J. H. Correia

2009-12-01T23:59:59.000Z

109

Interdiffusion between Zr Diffusion Barrier and U-Mo Alloy  

Science Conference Proceedings (OSTI)

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.

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

2012-12-01T23:59:59.000Z

110

Synthesis and structural investigation of the compounds containing HF{sub 2}{sup -} anions: Ca(HF{sub 2}){sub 2}, Ba{sub 4}F{sub 4}(HF{sub 2})(PF{sub 6}){sub 3} and Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6})  

SciTech Connect

Three new compounds Ca(HF{sub 2}){sub 2}, Ba{sub 4}F{sub 4}(HF{sub 2})(PF{sub 6}){sub 3} and Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6}) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF{sub 5}. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF{sub 2}){sub 2} was prepared by simply dissolving CaF{sub 2} in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H{sub 3}F{sub 4}){sub 2}. The compounds Ba{sub 4}F{sub 4}(HF{sub 2})(PF{sub 6}){sub 3} and Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6}) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF{sup +}){sub n} besides PbF(AsF{sub 6}), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba{sub 4}F{sub 4}(HF{sub 2})(PF{sub 6}){sub 3} crystallizes in a triclinic space group P1-bar with a=4.5870(2) A, b=8.8327(3) A, c=11.2489(3) A, {alpha}=67.758(9){sup o}, {beta}=84.722(12), {gamma}=78.283(12){sup o}, V=413.00(3) A{sup 3} at 200 K, Z=1 and R=0.0588. Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6}) at 200 K: space group P1-bar , a=4.5722(19) A, b=4.763(2) A, c=8.818(4) A, {alpha}=86.967(10){sup o}, {beta}=76.774(10){sup o}, {gamma}=83.230(12){sup o}, V=185.55(14) A{sup 3}, Z=1 and R=0.0937. Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6}) at 293 K: space group P1-bar, a=4.586(2) A, b=4.781(3) A, c=8.831(5) A, {alpha}=87.106(13){sup o}, {beta}=76.830(13){sup o}, {gamma}=83.531(11){sup o}, V=187.27(18) A{sup 3}, Z=1 and R=0.072. Ca(HF{sub 2}){sub 2} crystallizes in an orthorhombic Fddd space group with a=5.5709(6) A, b=10.1111(9) A, c=10.5945(10) A, V=596.77(10) A{sup 3} at 200 K, Z=8 and R=0.028. - Graphical abstract: Three new compounds Ca(HF{sub 2}){sub 2}, Ba{sub 4}F{sub 4}(HF{sub 2})(PF{sub 6}){sub 3} and Pb{sub 2}F{sub 2}(HF{sub 2})(PF{sub 6}) were obtained in the system metal(II) fluoride and anhydrous HF acidified with excessive PF{sub 5} and characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ca(HF{sub 2}){sub 2} represents the second known compound with homoleptic HF{sub 2}{sup -} environment of the central atom. Display Omitted.

Bunic, Tina; Tramsek, Melita [Department of Inorganic Chemistry and Technology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Goreshnik, Evgeny [Department of Inorganic Chemistry and Technology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: evgeny.goreshnik@ijs.si; Zemva, Boris [Department of Inorganic Chemistry and Technology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: boris.zemva@ijs.si

2008-09-15T23:59:59.000Z

111

Chemistry of H2O and HF Under Extreme Conditions  

DOE Green Energy (OSTI)

The predicted high pressure superionic phases of water and HF are investigated via ab initio molecular dynamics. These phases could potentially be achieved through either static compression with heating or through shock compression. We study water at densities of 2.0-3.0 g/cc (34-115 GPa) along the 2000K isotherm.We find that extremely rapid (superionic) diffusion of protons occurs in a fluid phase at pressures between 34 and 58 GPa. A transition to a stable body-centered cubic (bcc) O lattice with superionic proton conductivity is observed between 70 and 75 GPa, a much higher pressure than suggested in prior work. We find that all molecular species at pressures greater than 75 GPa are too short lived to be classified as bound states. Up to 95 GPa, we find a solid superionic phase characterized by covalent O-H bonding. Above 95 GPa, a transient network phase is found characterized by symmetric O-H hydrogen bonding with nearly 50% covalent character. Ab initio molecular dynamics simulations of HF were conducted at densities of 1.8-4.0 g/cc along the 900 K isotherm. According to our simulations, a unique form of (symmetric) hydrogen bonding could play a significant role in superionic conduction. Our work shows that superionic phases could be more prevalent in hydrogen bonded systems than previously thought, such as HCl and HBr.

Fried, L; Goldman, N; Kuo, I W; Mundy, C

2005-11-28T23:59:59.000Z

112

Recent advances in RF power generation  

SciTech Connect

This paper is a review of the progress and methods used in RF generation for particle accelerators. The frequencies of interest are from a few megahertz to 100 GHz, and the powers are for super linear collider applications, but in this case the pulses are short, generally below 1 {mu}s. The very high-power, short-pulse generators are only lightly reviewed here, and for more details the reader should follow the specialized references. Different RF generators excel over various parts of the frequency spectrum. Below 100 MHz solid-state devices and gridded tubes prevail, while the region between 400 MHz and 3 GHz, the cyclotron-resonant devices predominate, and above 250 GHz, Free-Electron Lasers and ubitrons are the most powerful generators. The emphasis for this review is on microwave generation at frequencies below 20 GHz, so the cyclotron-resonant devices are only partially reviewed, while the progress on free-electron laser and ubitrons is not reviewed in this paper. 39 refs., 4 figs.

Tallerico, P.J.

1990-01-01T23:59:59.000Z

113

Extremely high frequency RF effects on electronics.  

SciTech Connect

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.

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

114

Fermilab Tevatron high level rf accelerating systems  

SciTech Connect

Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer.

Kerns, Q.; Kerns, C.; Miller, H.; Tawser, S.; Reid, J.; Webber, R.; Wildman, D.

1985-06-01T23:59:59.000Z

115

The mechanism of HF formation in LiPF6 based organic carbonate electrolytes  

NLE Websites -- All DOE Office Websites (Extended Search)

The mechanism of HF formation in LiPF6 based organic carbonate electrolytes The mechanism of HF formation in LiPF6 based organic carbonate electrolytes Title The mechanism of HF formation in LiPF6 based organic carbonate electrolytes Publication Type Journal Article Year of Publication 2012 Authors Lux, Simon F., Ivan T. Lucas, Elad Pollak, Stefano Passerini, Martin Winter, and Robert Kostecki Journal Electrochemistry Communications Volume 14 Start Page 47 Issue 1 Pagination 47-50 Date Published 01/2012 Keywords Hydrofluoric acid, LiPF6 degradation, Lithium ion batteries, spectroscopic ellipsometry Abstract Spectroscopic ellipsometry was used to study the time-dependent formation of HF upon the thermal degradation of LiPF6 at 50 °C in a lithium ion battery electrolyte containing ethylene carbonate and diethyl carbonate. The generated HF was monitored by following the etching rate of a 300 nm thick SiO2 layer, grown on both sides of a silicon wafer substrate, as a function of the immersion time in the electrolyte at 50 °C. It was found that the formation of HF starts after 70 h of exposure time and occurs following several different phases. The amount of generated HF was calculated using an empirical formula correlating the etching rate to the temperature. Combining the results of the HF formation with literature data, a simplified mechanism for the formation of the HF involving LiPF6 degradation, and a simplified catalytical reaction pathway of the formed HF and silicon dioxide are proposed to describe the kinetics of HF formation.

116

Booster Synchrotron RF System Upgrade for SPEAR3  

Science Conference Proceedings (OSTI)

Recent progress at the SPEAR3 includes the increase in stored current from 100 mA to 200 mA and top-off injection to allow beamlines to stay open during injection. Presently the booster injects 3.0 GeV beam to SPEAR3 three times a day. The stored beam decays to about 150 mA between the injections. The growing user demands are to increase the stored current to the design value of 500 mA, and to maintain it at a constant value within a percent or so. To achieve this goal the booster must inject once every few minutes. For improved injection efficiency, all RF systems at the linac, booster and SPEAR3 need to be phase-locked. The present booster RF system is basically a copy of the SPEAR2 RF system with 358.5 MHz and 40 kW peak RF power driving a 5-cell RF cavity for 1.0 MV gap voltage. These requirements entail a booster RF system upgrade to a scaled down version of the SPEAR3 RF system of 476.3 MHz with 1.2 MW cw klystron output power capabilities. We will analyze each subsystem option for their merits within budgetary and geometric space constraints. A substantial portion of the system will come from the decommissioned PEP-II RF stations.

Park, Sanghyun; /SLAC; Corbett, Jeff; /SLAC

2012-07-06T23:59:59.000Z

117

Self-homodyne RF-optical microdisk receiver  

E-Print Network (OSTI)

modulation with optical transfer function (Po VRF 2 ) Self-homodyne RF-photonic receiver f ip Nonlinear and nonlinear modulation Transmittedoptical power t Wavelength t t Linear (Po VRF) Nonlinear (Po VRF 2) VRF ),,,,,( , 0 2 0 2 2 tPQGf dV Pd N EinoV VRF RF == = Microdisk optical mixer (laser= res) GV : voltage gain Q

Levi, Anthony F. J.

118

ITO Thin Films by RF Sputtering for Ethanol Sensing  

Science Conference Proceedings (OSTI)

The sensor for detection of ethanol vapours using RF sputter deposited ITO thin film on glass and Si substrates is reported. The principle of operation is the change of resistance of ITO film on exposure to ethanol vapours. The films were annealed at ... Keywords: Indium Tin Oxide, RF sputtering, ethanol sensor

Sudhir Chandra; H. J. Pandya; A. L. Vyas

2010-07-01T23:59:59.000Z

119

RF cavity using liquid dielectric for tuning and cooling  

SciTech Connect

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.

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

2012-04-17T23:59:59.000Z

120

A high-power L-band RF window  

E-Print Network (OSTI)

June. 2001. [3] "700 MHz Window R&D at LBNL", R. Rimmer et.Testing of PEP-II RF Cavity Windows", M. Neubauer et. al. ,A HIGH-POWER L-BAND RF WINDOW* R.A. Rimmer † , G. Koehler,

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

RF-MEMS capacitive switches with high reliability  

DOE Patents (OSTI)

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.

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

122

RF Power Degradation of GaN High Electron Mobility Transistors  

E-Print Network (OSTI)

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 ...

Joh, Jungwoo

123

Progress on the RF Coupling Coil Module Design for the MICE Channel  

E-Print Network (OSTI)

Spallation Neutron Source (SNS) type ceramic RF windows arecouplers together with the SNS-type ceramic RF window. Ahigh power tested now at the SNS RF test lab. Cavity length

2005-01-01T23:59:59.000Z

124

Interfacial and structural properties of sputtered HfO{sub 2} layers  

SciTech Connect

Magnetron sputtered HfO{sub 2} layers formed on a heated Si substrate were studied by spectroscopic ellipsometer (SE), x-ray diffraction (XRD), Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS) depth profiling techniques. The results show that the formation of a SiO{sub x} suboxide layer at the HfO{sub 2}/Si interface is unavoidable. The HfO{sub 2} thickness and suboxide formation are highly affected by the growth parameters such as sputtering power, O{sub 2}/Ar gas ratio during sputtering, sputtering time, and substrate temperature. XRD spectra show that the deposited film has (111) monoclinic phase of HfO{sub 2}, which is also supported by FTIR spectra. The atomic concentration and chemical environment of Si, Hf, and O have been measured as a function of depth starting from the surface of the sample by XPS technique. It shows that HfO{sub 2} layers of a few nanometers are formed at the top surface. Below this thin layer, Si-Si bonds are detected just before the Si suboxide layer, and then the Si substrate is reached during the depth profiling by XPS. It is clearly understood that the highly reactive sputtered Hf atoms consume some of the oxygen atoms from the underlying SiO{sub 2} to form HfO{sub 2}, leaving Si-Si bonds behind.

Aygun, G. [Department of Physics, Izmir Institute of Technology, Urla, TR-35430 Izmir (Turkey); Yildiz, I. [Department of Physics, Middle East Technical University, TR-06531 Ankara (Turkey); Central Laboratory, Middle East Technical University, TR-06531 Ankara (Turkey)

2009-07-01T23:59:59.000Z

125

Proposal for high pressure RF cavity test in the MTA  

DOE Green Energy (OSTI)

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.

Yonehara, K.; /Fermilab

2010-09-01T23:59:59.000Z

126

Cold Test Measurements on the GTF Prototype RF Gun  

Science Conference Proceedings (OSTI)

The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. Based on longitudinal phase space measurements showing a correlated energy spread the gun was removed and re-characterized in 2002. The low power RF measurements performed on the gun are described below. Perturbative bead measurements were performed to determine the field ratio in the two-cell gun, and network analyzer measurements were made to characterize the mode structure. A second probe was installed to monitor the RF field in the first cell, and a diagnostic was developed to monitor the high-power field ratio. Calibration of the RF probes, a model for analyzing RF measurements, and Superfish simulations of bead and RF measurements are described.

Gierman, S.M.

2010-12-03T23:59:59.000Z

127

Automated Hydroforming of Seamless Superconducting RF Cavity  

SciTech Connect

We are studying the possibility of automated hydroforming process for seamless superconducting RF cavities. Preliminary hydroforming tests of three-cell cavities from seamless tubes made of C1020 copper have been performed. The key point of an automated forming is to monitor and strictly control some parameters such as operation time, internal pressure and material displacements. Especially, it is necessary for our studies to be able to control axial and radial deformation independently. We plan to perform the forming in two stages to increase the reliability of successful forming. In the first stage hydroforming by using intermediate constraint dies, three-cell cavities were successfully formed in less than 1 minute. In parallel, we did elongation tests on cavity-quality niobium and confirmed that it is possible to achieve an elongation of >64% in 2 stages that is required for our forming of 1.3 GHz cavities.

Nagata, Tomohiko [ULVAC, Inc.; Shinozawa, Seiichi [ULVAC, Inc.; Abe, Noriyuki [ULVAC, Inc.; Nagakubo, Junki [ULVAC, Inc.; Murakami, Hirohiko [ULVAC, Inc.; Tajima, Tsuyoshi [Los Alamos National Laboratory; Inoue, Hitoshi [High Energy Accelerator Research Organization, KEK; Yamanaka, Masashi [High Energy Accelerator Research Organization, KEK; Ueno, Kenji [High Energy Accelerator Research Organization, KEK

2012-07-31T23:59:59.000Z

128

Fast thermometry for superconducting rf cavity testing  

SciTech Connect

Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity.

Orris, Darryl; Bellantoni, Leo; Carcagno, Ruben H.; Edwards, Helen; Harms, Elvin Robert; Khabiboulline, Timergali N.; Kotelnikov, Sergey; Makulski, Andrzej; Nehring, Roger; Pischalnikov, Yuriy; /Fermilab

2007-06-01T23:59:59.000Z

129

Plasma rotation and rf heating in DIII-D  

SciTech Connect

In a variety of discharge conditions on DIII-D it is observed that rf electron heating reduces the toroidal rotation speed and core ion temperature. The rf heating can be with either fast wave or electron cyclotron heating and this effect is insensitive to the details of the launched toroidal wavenumber spectrum. To date all target discharges have rotation first established with co-directed neutral beam injection. A possible cause is enhanced ion momentum and thermal diffusivity due to electron heating effectively creating greater anomalous viscosity. Another is that a counter directed toroidal force is applied to the bulk plasma via rf driven radial current.

deGrassie, J.S.; Baker, D.R.; Burrell, K.H. [General Atomics, San Diego, CA (United States)] [and others

1999-05-01T23:59:59.000Z

130

On the Estimation of Climatological Z–R Relationships  

Science Conference Proceedings (OSTI)

A statistical framework for climatological Z–R parameter estimation is developed and simulation experiments are conducted to examine sampling properties of the estimators. Both parametric and nonparametric models are considered. For parametric ...

Witold F. Krajewski; James A. Smith

1991-10-01T23:59:59.000Z

131

Effects of Surface Strain on Oxygen Adsorption on Zr (0001)  

Science Conference Proceedings (OSTI)

Symposium, Materials and Fuels for the Current and Advanced Nuclear Reactors II ... octahedral sites between second and third Zr layers become most favorable because ... Alloys as Structural Materials in Generation IV Nuclear Power Plant.

132

Start Up of a Nb-1%Zr Potassium Heat Pipe From the Frozen State  

E-Print Network (OSTI)

The start up of a liquid-metal heat pipe from the frozen state was evaluated experimentally with a Nb-1%Zr heat pipe with potassium as the working fluid. The heat pipe was fabricated and tested at Los Alamos National Laboratory. RF induction heating was used to heat 13 cm of the 1-m-long heat pipe. The heat pipe and test conditions are well characterized so that the test data may be used for comparison with numerical analyses. An attempt was made during steady state tests to calibrate the heat input so that the heat input would be known during the transient cases. The heat pipe was heated to 675C with a throughput of 600 W and an input heat flux of 6 W/cm 2 . Steady state tests, start up from the frozen state, and transient variations from steady state were conducted. Nomenclature English L length m . mass flow rate PS power setting r radius q heat flux q" heat flux per unit area T temperature v voltage V volume x axial location on heat pipe Greek e porosity r resist...

Since Its Founding; David E. Glass; Michael A. Merrigan; J. Tom Sena

1998-01-01T23:59:59.000Z

133

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

SciTech Connect

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.

Guo, Jiquan; /SLAC

2009-03-20T23:59:59.000Z

134

High-spin excitations in {sup 158,159,160}Hf from recoil-decay tagging  

SciTech Connect

The 270-MeV {sup 58}Ni+{sup A}Pd reaction was used for the first recoil-decay tagging measurement with Gammasphere coupled to the Fragment Mass Analyzer at Argonne National Laboratory. Level structures of {sup 158}Hf and {sup 159}Hf are identified for the first time, and that of {sup 160}Hf is extended. The systematical behavior of the energy levels in neighboring isotones and isotopes, as well as the aligned angular momenta as a function of rotational frequency, are examined. (c) 2000 The American Physical Society.

Ding, K. Y. [Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Cizewski, J. A. [Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Seweryniak, D. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Amro, H. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Carpenter, M. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Davids, C. N. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Fotiades, N. [Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Janssens, R. V. F. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lauritsen, T. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lister, C. J. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)] (and others)

2000-09-01T23:59:59.000Z

135

Handbook for Gas Filled RF Cavity Aficionados'  

DOE Green Energy (OSTI)

The use of hydrogen gas filled RF cavities in muon cooling channels has been proposed by Rolland Johnson. Impressive results have been obtained toward attaining high voltage gradients and rapid training in preliminary tests done at the FNAL MTA facility. However, so far it has not been possible to test them under conditions where they were subject to the transversal of a high intensity particle beam. This note is an attempt to bring together a description of some of the pertinent physical processes that take place in the dilute plasma that is generated in the hydrogen gas by the beam. Two effects dominate. The first is that the free electrons generated can load down the cavity and transfer its energy to heating the gas. The second is a question of what happens to the plasma in the longer term. There is an enormous literature on the subject of the subject of dilute hydrogen plasmas and we can tap into this information in order to understand and predict the behavior of the cavity.

Tollestrup, A.V.; Chung, Moses; Yonehara, Katsuya; /Fermilab

2009-05-01T23:59:59.000Z

136

RF Micro Devices Inc RFMD | Open Energy Information  

Open Energy Info (EERE)

RF Micro Devices Inc RFMD RF Micro Devices Inc RFMD Jump to: navigation, search Name RF Micro Devices, Inc. (RFMD) Place Greensboro, North Carolina Zip 27409-9421 Product RF Micro Devices, Inc. is a global leader in the design and manufacture of high-performance semiconductor components. Coordinates 44.576059°, -72.294016° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":44.576059,"lon":-72.294016,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

137

Rf system for the NSLS coherent infrared radiation source  

Science Conference Proceedings (OSTI)

The existing NSLS X-ray Lithography Source (XLS Phase I) is being considered for a coherent synchrotron radiation source. The existing 211 MHz warm cavity will be replaced with a 5-cell 2856 MHz superconducting RF cavity, driven by a series of 2 kW klystrons. The RF system will provide a total V{sub RF} of 1.5 MV to produce {sigma}{sub L} = 0.3 mm electron bunches at an energy of 150 MeV. Superconducting technology significantly reduces the required space and power needed to achieve the higher voltage. It is the purpose of this paper to describe the superconducting RF system and cavity, power requirements, and cavity design parameters such as input coupling, Quality Factor, and Higher Order Modes.

Broome, W.; Biscardi, R.; Keane, J.; Mortazavi, P.; Thomas, M.; Wang, J.M.

1995-05-01T23:59:59.000Z

138

Efficiency enhancement techniques for RF and millimeter wave power amplifiers  

E-Print Network (OSTI)

Power amplifiers are the circuit blocks in wireless transceivers that require the largest power budget because of their relatively low efficiencies. RF designers cannot depend solely on the development better semiconductor ...

Ogunnika, Olumuyiwa Temitope, 1978-

2012-01-01T23:59:59.000Z

139

Channel engineering of SOI MOSFETs for RF applications  

E-Print Network (OSTI)

Channel engineering of SOI MOSFETs is explored by altering ion implantation without adding any new fabrication steps to the standard CMOS process. The effects of implantation on characteristics important for RF applications, ...

Keast, Craig L.

140

An improved RF cavity search for halo axions  

E-Print Network (OSTI)

The axion is a hypothetical elementary particle and cold dark matter candidate. In this RF cavity experiment, halo axions entering a resonant cavity immersed in a static magnetic field convert into microwave photons, with ...

Yu, D. B. (Daniel Byungyoon), 1976-

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

High Frequency High Power RF Generation using a Relativistic...  

NLE Websites -- All DOE Office Websites (Extended Search)

FREQUENCY HIGH POWER RF GENERATION USING A RELATIVISTIC ELECTRON BEAM C. Jing , S. Antipov, P. Schoessow, and A. Kanareykin, Euclid Techlabs LLC, Solon, OH-44139 J.G. Power, M....

142

Hom dampers for ALS storage ring RF cavities  

E-Print Network (OSTI)

of the HOM dampers on ALS rf cavities was an immediatesuccess. Now, the ALS storage ring can operate with the 312The cross-section of the ALS third harmonic cavity with two

2003-01-01T23:59:59.000Z

143

Electrodeless lighting RF power source development. Final report  

SciTech Connect

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.

NONE

1996-08-30T23:59:59.000Z

144

ANALYZING SURFACE ROUGHNESS DEPENDENCE OF LINEAR RF LOSSES  

SciTech Connect

Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

Reece, Charles E. [JLAB; Kelley, Michael J. [JLAB, W& M College; Xu, Chen [JLAB, W& M College

2012-09-01T23:59:59.000Z

145

A Test and Diagnosis Methodology for RF Transceivers  

Science Conference Proceedings (OSTI)

This paper proposes an RF test and diagnosis methodology based on digital DFT structure and builtin DSP function of a SoC Chip. Constellation variation plots are proposed to identify the faulty component. Furthermore, linear interpolation is used to ...

Hung-kai Chen; Chauchin Su

2007-10-01T23:59:59.000Z

146

Test estructural i predictiu per a circuits RF CMOS.  

E-Print Network (OSTI)

??En aquesta tesi s'ha desenvolupat una tècnica de test que permet testar un LNA i un mesclador, situats en el capçal RF d'un receptor CMOS,… (more)

Suenaga Portugués, Kay

2008-01-01T23:59:59.000Z

147

BN/Graphene/BN Transistors for RF Applications  

E-Print Network (OSTI)

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 ...

Taychatanapat, Thiti

148

Recent Progress of RF Cavity Study at Mucool Test Area  

DOE Green Energy (OSTI)

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.

Yonehara, Katsuya; /Fermilab

2011-12-02T23:59:59.000Z

149

Micropower RF transponder with superregenerative receiver and RF receiver with sampling mixer  

DOE Patents (OSTI)

A micropower RF transponder employs a novel adaptation of the superregenerative receiver wherein the quench oscillator is external to the regenerative transistor. The quench oscillator applies an exponentially decaying waveform rather than the usual sinewave to achieve high sensitivity at microampere current levels. Further improvements include circuit simplifications for antenna coupling, extraction of the detected signal, and a low-voltage bias configuration that allows operation with less than a 1-volt rail voltage. The inventive transponder is expected to operate as long as the battery shelf life. 13 figs.

McEwan, T.E.

1997-05-13T23:59:59.000Z

150

Micropower RF transponder with superregenerative receiver and RF receiver with sampling mixer  

DOE Patents (OSTI)

A micropower RF transdponder employs a novel adaptation of the superregenerative receiver wherein the quench oscillator is external to the regenerative transistor. The quench oscillator applies an exponentially decaying waveform rather than the usual sinewave to achieve high sensitivity at microampere current levels. Further improvements include circuit simplifications for antenna coupling, extraction of the detected signal, and a low-voltage bias configuration that allows operation with less than a 1-volt rail voltage. The inventive transponder is expected to operate as long as the battery shelf life.

McEwan, Thomas E. (Livermore, CA)

1997-01-01T23:59:59.000Z

151

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)  

E-Print Network (OSTI)

RF and Beam Diagnostic Instrumentation at the Advanced Photon Source (APS) Linear Accelerator (Linac)

Grelick, A E; Arnold, N; White, M

1996-01-01T23:59:59.000Z

152

Rf power systems for the national synchrotron light source  

SciTech Connect

The booster synchrotron and the two storage rings at the NSLS are provided with rf power systems of 3 kW, 50 kW, and 500 kW nominal output power, all at 53 MHz. This power is supplied by grounded grid tetrode amplifiers designed for television broadcast service. These amplifiers and associated power supplies, control and interlock systems, rf controls, and computer interface are described.

Dickinson, T.; Rheaume, R.H.

1981-01-01T23:59:59.000Z

153

COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS  

Science Conference Proceedings (OSTI)

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.

Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

2011-03-01T23:59:59.000Z

154

Optimal Control Theory Applied to an Objective Analysis of a Tidal Current Mapping by HF Radar  

Science Conference Proceedings (OSTI)

Optimal control can provide a tool to perform an optimization of a tidal model via a data assimilation operation. A pilot study is presented here to test the theoretical and numerical feasibility of an assimilation of HF radar current ...

Jean-Luc Devenon

1990-04-01T23:59:59.000Z

155

Observation of Wave Energy Evolution in Coastal Areas Using HF Radar  

Science Conference Proceedings (OSTI)

The capability of phased-array HF radar systems to sample the spatial distribution of wave energy is investigated in different storm scenarios and coastal configurations. First, a formulation introduced by D. E. Barrick to extract significant ...

Rafael J. Ramos; Hans C. Graber; Brian K. Haus

2009-09-01T23:59:59.000Z

156

Human equivalent antenna model for HF exposures: analytical versus numerical approach  

Science Conference Proceedings (OSTI)

In this paper, the human exposure to HF radiation is analyzed using the simplified human equivalent antenna model featuring analytical and numerical approach, respectively. Namely, the human body is represented by an equivalent receiving straight thin ...

Dragan Poljak; Silvestar Sesnic; Ivana Zulim

2009-09-01T23:59:59.000Z

157

Surface Termination and Roughness of Ge(100) Cleaned by HF and HCl Solutions  

DOE Green Energy (OSTI)

Oxide removal from Ge(100) surfaces treated by HCl and HF solutions with different concentrations are systematically studied by synchrotron radiation photoelectron spectroscopy (SR-PES). SR-PES results show that clean surfaces without any oxide can be obtained after wet chemical cleaning followed by vacuum annealing with a residual carbon contamination of less than 0.02 monolayer. HF etching leads to a hydrogen terminated Ge surface whose hydrogen coverage is a function of the HF concentration. In contrast, HCl etching yields a chlorine terminated surface. Possible etching mechanisms are discussed. Surface roughness after HF and HCl treatments is also investigated by AFM, which shows that HF treatment leaves a rougher surface than HCl. Germanium (Ge) is increasingly being studied for MOSFET applications to take advantage of its high intrinsic electron and hole mobility. To fabricate high performance devices on Ge, it is essential to understand Ge surface chemistry and find an effective way to clean and passivate its surface. Although Si surface cleaning and passivation have been extensively studied, only recently has some research been done on Ge surfaces. Conventional XPS results show that HF etching removes Ge oxide and carbon contamination significantly, and HCl etching leads to a chlorine terminated Ge(111) surface, which only forms Ge monochloride. However, it is difficult to probe the details of the chemical nature of treated surfaces and quantify the surface termination and cleanness with conventional XPS, because of its limited surface sensitivity and resolution. In addition, little attention has been paid to the HF concentration, which turns out to be an important factor in the surface hydrogen passivation. In this work, we study the Ge(100) surfaces treated by aqueous HCl and HF solutions with three different concentrations by synchrotron radiation photoelectron spectroscopy (SR-PES) at Stanford Synchrotron Radiation Laboratory (SSRL). Using SR-PES, we can tune the photon energy to achieve very high surface sensitivity and good resolution, so the chemical states of treated surfaces can be resolved unambiguously, and the surface termination and cleanness can be quantified. We find that HF treatment results in a hydrogen terminated surface, and the hydrogen coverage depends on the HF concentration. In contrast, a Cl terminated Ge(100) surface is achieved after HCl treatment. Both monochloride and dichloride are formed on the surface. The termination difference between HF etching and HCl etching can be explained by the etching mechanism. In both cases, the residual carbon and oxygen after chemical etching can be removed by vacuum annealing.

Sun, Shiyu; /SLAC, SSRL

2005-10-10T23:59:59.000Z

158

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

SciTech Connect

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.

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

2010-08-29T23:59:59.000Z

159

Pygmy dipole strength in {sup 90}Zr  

SciTech Connect

The dipole response of the N=50 nucleus {sup 90}Zr was studied in photon-scattering experiments at the electron linear accelerator ELBE with bremsstrahlung produced at kinetic electron energies of 7.9, 9.0, and 13.2 MeV. We identified 189 levels up to an excitation energy of 12.9 MeV. Statistical methods were applied to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. In this way we derived the photoabsorption cross section up to the neutron-separation energy. This cross section matches well the photoabsorption cross section obtained from ({gamma}, n) data and thus provides information about the extension of the dipole-strength distribution toward energies below the neutron-separation energy. An enhancement of E1 strength has been found in the range of 6 to 11 MeV. Calculations within the framework of the quasiparticle-phonon model ascribe this strength to a vibration of the excessive neutrons against the N=Z neutron-proton core, giving rise to a pygmy dipole resonance.

Schwengner, R.; Rusev, G.; Benouaret, N.; Beyer, R.; Erhard, M.; Junghans, A. R.; Klug, J.; Kosev, K.; Nair, C.; Schilling, K. D.; Wagner, A. [Institut fuer Strahlenphysik, Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); Tsoneva, N. [Institut fuer Theoretische Physik, Universitaet Giessen, D-35392 Giessen (Germany); Institute for Nuclear Research and Nuclear Energy, BAS, BG-1784 Sofia (Bulgaria); Grosse, E. [Institut fuer Strahlenphysik, Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Lenske, H. [Institut fuer Theoretische Physik, Universitaet Giessen, D-35392 Giessen (Germany)

2008-12-15T23:59:59.000Z

160

Atomic-Scale Structure of Al2O3-ZrO2 Mixed Oxides Prepared by Laser Ablation  

Science Conference Proceedings (OSTI)

By means of x-ray diffractometry (XRD) and X-ray absorption fine structure spectroscopy, the phase composition and atomic structure of laser evaporated ZrO2 and ZrO2-Al2O3 nanopowders have been studied. The results indicate that pure ZrO2 exists in the form of tetragonal structure, Al2O3 doped ZrO2 nanoparticles, however, have cubic structure. Compared to bulk tetragonal ZrO2, pure tetragonal ZrO2 nanoparticles have a shorter Zr-O- and Zr-Zr shell, indicating that the lattice contracts with decreasing particle size. For Al2O3 doped ZrO2 solid solution, the distances of first Zr-O and Zr-Zr (Al) coordination decrease with increasing solid solubility. The disorder degree of the ZrO2 lattice increases with increasing solid solubility. The coevaporated ZrO2-Al2O3 is quickly solidified into amorphous phase when it is ablated in a higher pressure. The amorphous phase contains Zr-O-Zr (Al) clusters and has shorter Zr-O distance and tower Zr-O coordination number.

Yang Xiuchun [College of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Dubiel, M. [Department of Physics, Martin Luther University of Halle, D-06108 Halle (Germany); Hofmeister, H. [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Riehemann, W. [Department of Materials Science and Engineering, Clausthal University of Technology (Germany)

2007-02-02T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

RF-Plasma Source Commissioning in Indian Negative Ion Facility  

Science Conference Proceedings (OSTI)

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.

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

162

Formation of HfW2 in Mechanically Alloyed W-Based Alloy Systems  

Science Conference Proceedings (OSTI)

Abstract Scope, The lethality of depleted uranium (DU) as a kinetic energy penetrator ... An alternative replacement, a tungsten (W)-based bulk metallic glass would .... Oxidation Resistance of Zr- and Ti- Based Bulk Metallic Glasses in the ...

163

Microsoft PowerPoint - rf_5year_review  

NLE Websites -- All DOE Office Websites (Extended Search)

RF Research Program RF Research Program DOE Review of C-Mod Five-Year Proposal May 13-14, 2003 MIT PSFC Presented by Steve J.Wukitch Outline: 1. Overview of the RF Program 2. Five-year plan Overview of the RF Program AT: validate steady state operation with target parameters β N = 3, I non = 100%, I BS ~ 70%, H 89 ~ 2.5, for t pulse > t L/R . BPX: demonstrate the viability of high performance plasmas, B T = 8T, I p = 2 MA, P = 6 MW, H 89 ≥ 2, Z eff < 1.5. B T = 5.4T, I p = 1.4 MA, P = 6 MW, H 89 = 2 (ITER demo) Exclusively use RF power for auxiliary heating and current drive. variable variable fixed Phase 2 x 4 Strap 4 Strap 2 x 2 Strap Antenna 4 MW 40-80 MHz J-port 2 x 4 MW 2 x 2 MW Power 40-80 MHz ~ 80 MHz Frequency E & J-port D & E-port 2005-2008 2002-2005 4.6 GHz 4.6 GHz Frequency 16 x 250 kW

164

A 12 GHz RF Power Source for the CLIC Study  

SciTech Connect

The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for CLIC accelerating structure testing. A design and fabrication contract for five klystrons at that frequency has been signed by different parties with SLAC. France (IRFU, CEA Saclay) is contributing a solid state modulator purchased in industry and specific 12 GHz RF network components to the CLIC study. RF pulses over 120 MW peak at 230 ns length will be obtained by using a novel SLED-I type pulse compression scheme designed and fabricated by IAP, Nizhny Novgorod, Russia. The X-band power test stand is being installed in the CLIC Test Facility CTF3 for independent structure and component testing in a bunker, but allowing, in a later stage, for powering RF components in the CTF3 beam lines. The design of the facility, results from commissioning of the RF power source and the expected performance of the Test Facility are reported.

Schirm, Karl; /CERN; Curt, Stephane; /CERN; Dobert, Steffen; /CERN; McMonagle, Gerard; /CERN; Rossat, Ghislain; /CERN; Syratchev, Igor; /CERN; Timeo, Luca; /CERN; Haase, Andrew /SLAC; Jensen, Aaron; /SLAC; Jongewaard, Erik; /SLAC; Nantista, Christopher; /SLAC; Sprehn, Daryl; /SLAC; Vlieks, Arnold; /SLAC; Hamdi, Abdallah; /Saclay; Peauger, Franck; /Saclay; Kuzikov, Sergey; /Nizhnii Novgorod, IAP; Vikharev, Alexandr; /Nizhnii Novgorod, IAP

2012-07-03T23:59:59.000Z

165

RF Power Upgrade for CEBAF at Jefferson Laboratory  

Science Conference Proceedings (OSTI)

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.

Andrew Kimber,Richard Nelson

2011-03-01T23:59:59.000Z

166

rf improvements for Spallation Neutron Source H ion source  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering 38 mA H beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride AlN plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier. 2010 American Institute of Physics.

Kang, Yoon W [ORNL; Fuja, Raymond E [ORNL; Goulding, Richard Howell [ORNL; Hardek, Thomas W [ORNL; Lee, Sung-Woo [ORNL; McCarthy, Mike [ORNL; Piller, Chip [ORNL; Shin, Ki [ORNL; Stockli, Martin P [ORNL; Welton, Robert F [ORNL

2010-01-01T23:59:59.000Z

167

Microstructure and Bonding Behavior of a New Zr-Bearing Interlayer ...  

Science Conference Proceedings (OSTI)

Winnipeg, Manitoba, Canada R3T 2N2. Abstract. Based on the composition of the interdendritic Zr-rich melt in the later stages of solidification of. Zr-containing ...

168

SP-29: Oxidation Behavior of Zr56Al16Co28 Metallic Glasses  

Science Conference Proceedings (OSTI)

Abstract Scope, The oxidation behavior of Zr56A16Co28 bulk metallic glass was ... A high resistance against oxidation in Zr56Al16Co28 bulk metallic glasses ...

169

Atomistic Modeling of Fission Products Transport in SiC and ZrC ...  

Science Conference Proceedings (OSTI)

Some studies have suggested the ZrC can provide improved fission product retention compared to SiC and ZrC is presently under consideration for use with,

170

Enthalpy of gamma-delta Transition in Ternary U-Pu-Zr Fuel Alloys  

Science Conference Proceedings (OSTI)

Presentation Title, Enthalpy of gamma-delta Transition in Ternary U-Pu-Zr Fuel ... that the activities of Pu and Zr in the delta phase may be self-compensating.

171

Lanthanum diffusion in the TiN/LaOx/HfSiO/SiO2/Si stack  

Science Conference Proceedings (OSTI)

Band edge Complementary Metal Oxide Semiconductor (CMOS) devices are obtained by insertion of a thin LaO"x layer between the high-k (HfSiO) and metal gate (TiN). High temperature post deposition anneal induces Lanthanum diffusion across the HfSiO towards ... Keywords: APT, ATR-FTIR, HfSiO, Interfacial dipole, La, Metal/high-k stack, S-XPS, Threshold voltage tuning, TiN, ToF-SIMS

E. Martinez; P. Ronsheim; J. -P. Barnes; N. Rochat; M. Py; M. Hatzistergos; O. Renault; M. Silly; F. Sirotti; F. Bertin; N. Gambacorti

2011-07-01T23:59:59.000Z

172

A computer program for HVDC converter station RF noise calculations  

SciTech Connect

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.

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

173

Control of the LHC 400 MHz RF System (ACS)  

E-Print Network (OSTI)

The LHC ACS RF system is composed of 16 superconducting cavities, eight per ring. Each ring has two cryomodules, each containing four cavities. Each cavity is powered by a 300 kW klystron. The klystrons are grouped in fours, the klystrons in each group sharing a common 58 kV power converter and HV equipment bunker. The ACS RF control system is based on modern industrial programmable controllers (PLCs). A new fast interlock and alarm system with inbuilt diagnostics has been developed. Extensive use of the FIPIO Fieldbus drastically decreases the cabling complexity and brings improved signal quality, increased reliability and easier maintenance. Features of the implementation, such as system layout, communication and the high-level software interface are described. Operational facilities such as the automatic switch on procedure are described, as well as the necessary specialist tools and interfaces. A complete RF chain, including high voltage, cryomodule and klystron is presently being assembled in order to ch...

Arnaudon, L; Maesen, P; Prax, M

2004-01-01T23:59:59.000Z

174

Overview and status of RF systems for the SSC Linac  

SciTech Connect

The Superconducting Super Collider (SSC) Linear Accelerator (Linac) produces a 600-MeV, 35-{mu}s, H-beam at a 10-Hz repetition rate. The beam is accelerated by a series of RF cavities. These consist of a Radio Frequency Quadrupole (RFQ), two bunchers, and four Drift Tube Linac (DTL) tanks at 427.617 MHz, and two bunchers, nine side-coupled Linac modules, and an energy compressor at 1282.851 MHz. The RFQ amplifier and the low-frequency buncher cavity amplifiers use gridded tubes, while the other cavities use klystron amplifier systems. The RF control system consists of a reference line and cavity feedback and feedforward loops for each amplifier. The RF amplifier system for each of these accelerator cavities is described, and the current status of each system is presented.

Mynk, J.; Grippe, J.; Cutler, R.I.; Rodriguez, R.

1993-05-01T23:59:59.000Z

175

Spectroscopic analysis of Al and N diffusion in HfO{sub 2}  

Science Conference Proceedings (OSTI)

X-ray photoelectron core level spectroscopy, secondary ion mass spectroscopy, spectroscopic ellipsometry, and extended x-ray absorption fine structure measurements have been employed to distinguish the effects of Al and N diffusion on the local bonding and microstructure of HfO{sub 2} and its interface with the Si substrate in (001)Si/SiO{sub x}/2 nm HfO{sub 2}/1 nm AlO{sub x} film structures. The diffusion of Al from the thin AlO{sub x} cap layer deposited on both annealed and unannealed HfO{sub 2} has been observed following anneal in N{sub 2} and NH{sub 3} ambient. Both N{sub 2} and NH{sub 3} subsequent anneals were performed to decouple incorporated nitrogen from thermal reactions alone. Causal variations in the HfO{sub 2} microstructure combined with the dependence of Al and N diffusion on initial HfO{sub 2} conditions are presented with respect to anneal temperature and ambient.

Lysaght, P. S.; Price, J.; Kirsch, P. D. [SEMATECH, 257 Fuller Rd, Albany, New York 12203 (United States); Woicik, J. C.; Weiland, C. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Sahiner, M. A. [Seton Hall University, 400 South Orange Ave, South Orange, New Jersey 07079 (United States)

2012-09-15T23:59:59.000Z

176

Performance and reliability improvement of HfSiON gate dielectrics using chlorine plasma treatment  

Science Conference Proceedings (OSTI)

The effects of chlorine plasma treatment on HfSiON gate dielectrics were investigated with respect to device performance and reliability characteristics. The chlorine plasma treatment was performed on atomic layer deposited HfSiON films to remove the residual carbon content. The optimal chlorine plasma treatment is shown to lower gate leakage current density without increasing equivalent oxide thickness of the gate stack. Secondary ion mass spectroscopy depth profiling showed that the carbon residue in HfSiON was reduced by the chlorine plasma treatment. It is demonstrated that an optimized chlorine plasma treatment improves the transistor I{sub on}-I{sub off} characteristics and reduces negative-bias temperature instability.

Park, Hong Bae; Ju, Byongsun [Samsung Electronics R and D Center (Korea, Republic of); Kang, Chang Yong; Park, Chanro; Park, Chang Seo [SEMATECH, Austin, Texas 78741 (United States); Lee, Byoung Hun [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Kim, Tea Wan; Kim, Beom Seok; Choi, Rino [Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751 (Korea, Republic of)

2009-01-26T23:59:59.000Z

177

First principles simulation of a superionic phase of hydrogen fluoride (HF) at high pressures and temperatures  

DOE Green Energy (OSTI)

The authors have conducted Ab initio molecular dynamics simulations of hydrogen fluoride (HF) at pressures of 5-66 GPa along the 900 K isotherm. They predict a superionic phase at 33 GPa, where the fluorine atoms are fixed in a bcc lattice while the hydrogen atoms diffuse rapidly with a diffusion constant of between 2 x 10{sup -5} and 5 x 10{sup -5} cm{sup 2}/s. They find that a transformation from asymmetric to symmetric hydrogen bonding occurs in HF at 66 GPa and 900 K. With superionic HF they have discovered a model system where symmetric hydrogen bonding occurs at experimentally achievable conditions. Given previous results on superionic H{sub 2}O[1,2,3] and NH{sub 3}[1], they conclude that high P,T superionic phases of electronegative element hydrides could be common.

Goldman, N; Fried, L E

2006-04-10T23:59:59.000Z

178

Band offsets in HfO{sub 2}/InGaZnO{sub 4} heterojunctions  

SciTech Connect

The valence band discontinuity ({Delta}E{sub V}) of sputter deposited HfO{sub 2}/InZnGaO{sub 4} (IGZO) heterostructures was obtained from x-ray photoelectron spectroscopy measurements. The HfO{sub 2} exhibited a bandgap of 6.07 eV from absorption measurements. A value of {Delta}E{sub V} = 0.48 {+-} 0.025 eV was obtained by using the Ga 2p{sub 3/2}, Zn 2p{sub 3/2}, and In 3d{sub 5/2} energy levels as references. This implies a conduction band offset {Delta}E{sub C} of 2.39 eV in HfO{sub 2}/InGaZnO{sub 4} heterostructures and a nested interface band alignment.

Cho, Hyun [Department of Nanomechatronics Engineering, Pusan National University, Gyeongnam 627-706 (Korea, Republic of); Douglas, E. A.; Gila, B. P.; Craciun, V.; Lambers, E. S.; Pearton, S. J. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Ren Fan [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2012-01-02T23:59:59.000Z

179

Encapsulation of Mg-Zr Fuel Cladding in Geopolymer Material  

Science Conference Proceedings (OSTI)

Symposium, Materials Science of Nuclear Waste Management ... Mg-Zr. Strategy could be to encapsulate these wastes into a geopolymer in a form suitable ... Delayed Hydride Cracking Susceptibility of Spent Fuel Rods in Dry Storage ... Isolation of Matrices for High-Level Radioactive Waste Using Metal Coatings Prepared ...

180

Evaluation of a New Polarimetrically Based Z–R Relation  

Science Conference Proceedings (OSTI)

A new polarimetrically based (or, pol-based) Z–R relation of the form Z = aR1.5 is described and evaluated where the multiplicative coefficient a is continuously adjusted as the drop size distribution evolves in space and time. The methodology is ...

V. N. Bringi; Taiwen Tang; V. Chandrasekar

2004-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

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

E-Print Network (OSTI)

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

Venturini, M.

2010-01-01T23:59:59.000Z

182

Dynamics of an electron in an rf gap  

Science Conference Proceedings (OSTI)

The purpose of this calculation is to understand the limitation on the energy transfer efficiency of an electron beam to the rf output cavity of a klystron or a lasertron. An output cavity with drift tubes is modeled in this calculation by a region of constant amplitude rf field with exponentially decreasing entrance and exit fringing fields. The exit velocity of an electron traversing such a gap is examined as a function of entrance phase for various values of the ratio of the peak rf cavity voltage to electron entrance voltage. Depending on this ratio, the dynamics of the electron motion can become quite complex. For a gap with fringe fields it is found that, even if the gap voltage and phase are optimized, the maximum energy that can be extracted from a short bunch is always significantly less than 100%. The case in which the electron is created with zero velocity in the gap, and subsequently leaves the gap having extracted energy from the rf field, is also treated. 4 refs., 10 figs.

Farkas, Z.D.; Wilson, P.B.

1989-03-01T23:59:59.000Z

183

RF Cherenkov picosecond timing technique for high energy physics applications  

Science Conference Proceedings (OSTI)

The Cherenkov time-of-propagation (TOP) detector and Cherenkov time-of-flight (TOF) detector in a ?head-on? geometry based on the recently proposed time measuring technique with radio frequency (RF) phototube are considered. Results of the Monte Carlo simulations are presented.

Margaryan, Amur; Hashimoto, Osamu; Majewski, Stanislaw; Tang, Liguang

2008-09-01T23:59:59.000Z

184

The RF, Communications and Intelligent Systems (RFCIS) Group  

E-Print Network (OSTI)

Federal Laboratory Consortium for Technology Transfer. Tagging, Tracking, and Locating Systems TTL and development (R&D) geared toward supplying robust communications for extreme environments; global tagging, tracking, and locating (TTL) systems; and RF- and microwave-based measurement and processing systems

185

RF coupler for high-power CW FEL photoinjector  

SciTech Connect

A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. The design presently under way is a 100-mA 2.5-cell {pi}-mode, 700-MHz, normal conducting demonstration CW RF photoinjector. This photoinjector will be capable of accelerating 3 nC per bunch with an emittance at the wiggler less than 10 mm-mrad. The paper presents results for the RF coupling from ridged wave guides to hte photoinjector RF cavity. The LEDA and SNS couplers inspired this 'dog-bone' design. Electromagnetic modeling of the coupler-cavity system has been performed using both 2-D and 3-D frequency-domain calculations, and a novel time-domain approach with MicroWave Studio. These simulations were used to adjust the coupling coefficient and calculate the power-loss distribution on the coupling slot. The cooling of this slot is a rather challenging thermal management project.

Kurennoy, S. (Sergey); Young, L. M. (Lloyd M.)

2003-01-01T23:59:59.000Z

186

Stochastic fluctuations of dust particle charge in RF discharges  

Science Conference Proceedings (OSTI)

In addition to RF oscillations, intrinsic stochastic fluctuations due to the discreteness of electrons and ions could be important to the charging of a dust particle in RF discharges. These fluctuations are studied in the present work for three cases [M. Bacharis et al., Plasma Sources Sci. Technol. 19, 025002 (2010)] relevant to RF discharges employing a recently proposed model [B. Shotorban, Phys. Rev. E 83, 066403 (2011)] valid for stochastic charging at nonstationary states. The cases are concerned with a time varying electron number density relevant to sheaths, a time varying electric field relevant to the bulk plasma, and a time-dependent bi-Maxwellian distribution of electrons in a low pressure discharge. Two dust particles with different sizes are individually studied in each case. The radius of one is ten times larger than the radius of the other. In all of the cases, for the larger dust particle, the root-mean-squre of charge stochastic fluctuations is about an order of magnitude smaller than the amplitude of RF charge oscillations, while for the smaller dust particle, they are comparable in magnitude.

Shotorban, B. [Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)

2012-05-15T23:59:59.000Z

187

The correlation of the electrical properties with electron irradiation and constant voltage stress for MIS devices based on high-k double layer (HfTiSiO: N and HfTiO:N) dielectrics  

Science Conference Proceedings (OSTI)

This paper describes the influence of e-beam irradiation and constant voltage stress on the electrical characteristics of metal-insulator-semiconductor structures, with double layer high-k dielectric stacks containing HfTiSiO:N and HfTiO:N ultra-thin ... Keywords: Electrical properties, High-k dielectrics, Metal-insulator-semiconductor (MIS) devices

V. Mikhelashvili; P. Thangadurai; W. D. Kaplan; G. Eisenstein

2010-11-01T23:59:59.000Z

188

Tubular Radio Frequency (RF) Cage Field Confinement Cavity (IN-05-107)  

Scientists at Argonne National Laboratory have created innovations in the design and fabrication of radio frequency (RF) cavities that improve ...

189

Design of RF Feed System for Standing-Wave Accelerator Structures  

Science Conference Proceedings (OSTI)

We are investigating a standing wave accelerator structure that uses a rf feed to each individual cell. This approach minimizes rf power flow and electromagnetic energy absorbed by an rf breakdown. The objective of this work is a robust high-gradient (above 100 MV/m) X-band accelerator structure.

Neilson, J.; Tantawi, S.; Dolgashev, V.; /SLAC

2012-05-25T23:59:59.000Z

190

Electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor capacitors with various nitrogen concentration profiles  

Science Conference Proceedings (OSTI)

The comparative studies of electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor (MOS) capacitors with various nitrogen concentration profiles (NCPs) were investigated. Various NCPs in HfLaON gate dielectrics were adjusted ... Keywords: Charge trapping, Current-conduction, High-k dielectric, Metal-oxide-semiconductor (MOS), Nitrogen concentration profiles (NCPs)

Chin-Lung Cheng; Jeng-Haur Horng; Hung-Yang Tsai

2011-02-01T23:59:59.000Z

191

MicroPlanet Technology Corp formerly HF Capital Corp | Open Energy  

Open Energy Info (EERE)

Technology Corp formerly HF Capital Corp Technology Corp formerly HF Capital Corp Jump to: navigation, search Name MicroPlanet Technology Corp (formerly HF Capital Corp) Place Seattle, Washington Zip 98104 Sector Efficiency Product MicroPlanet develops energy-efficiency products for homes and small businesses. Specifically they focus on custom voltage regulators that result in energy savings. On May 6, 2005, the company reverse-listed into Toronto Venture Exchange quoted HF Capital. Coordinates 47.60356°, -122.329439° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":47.60356,"lon":-122.329439,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

192

Improving HF Radar Surface Current Measurements with Measured Antenna Beam Patterns  

Science Conference Proceedings (OSTI)

A high-frequency (HF) radar system is deployed on the New Jersey continental shelf as part of a coastal ocean observatory. The system includes two remote transmit–receive sites in Brant Beach and Brigantine, New Jersey, and a central processing ...

Josh T. Kohut; Scott M. Glenn

2003-09-01T23:59:59.000Z

193

Properties of ALD HfTaxOy high-k layers deposited on chemical silicon oxide  

Science Conference Proceedings (OSTI)

HfTa"xO"y high-k dielectric layers with different compositions were deposited using ALD on 1nm SiO"2 generated by ozone based cleaning of 200mm Si(100) surface. Physical characterization of blanket layers and C-V mapping demonstrates that the ALD layers ...

C. Zhao; T. Witters; P. Breimer; J. Maes; M. Caymax; S. De Gendt

2007-01-01T23:59:59.000Z

194

Interpretation of Coastal HF Radar–Derived Surface Currents with High-Resolution Drifter Data  

Science Conference Proceedings (OSTI)

Dense arrays of surface drifters are used to quantify the flow field on time and space scales over which high-frequency (HF) radar observations are measured. Up to 13 drifters were repetitively deployed off the Santa Barbara and San Diego coasts ...

Carter Ohlmann; Peter White; Libe Washburn; Brian Emery; Eric Terrill; Mark Otero

2007-04-01T23:59:59.000Z

195

Vapor deposition of thin-film Y-doped ZrO{sub 2} for electrochemical device applications  

DOE Green Energy (OSTI)

Solid oxide electrolytes based on yttria-stabilized zirconia (YSZ) are widely used in applications such as oxygen sensors, solid oxide fuel cells, oxygen pumps, electrocatalytic reactors, and electrochemically driven oxygen separation membranes. However, bulk YSZ is used in these applications. This requires high operating temperatures in order to minimize ohmic loss. One alternative of overcoming this problem is to use a thin film of the electrolyte. In the work, the authors have grown polycrystalline thin films of fully stabilized Y-ZrO{sub 2} on thick porous Al{sub 2}O{sub 3} substrates in multilayer La{sub 1{minus}x}Sr{sub x}MEO{sub 3}YSZ/La{sub 1{minus}x}Sr{sub x}MEO{sub 3} (ME = Mn, Co) configurations using a combination of single-target RF magnetron sputtering and electron beam physical vapor deposition techniques. The structure and morphology of these films have been studied using X-ray diffraction, and Scanning Electron Microscopy techniques. The ionic conductivity of the thin films has been measured using AC impedance analysis.

Chung, B.W.; Brosha, E.L.; Brown, D.R.; Garzon, F.H.

1994-12-01T23:59:59.000Z

196

rf power system for thrust measurements of a helicon plasma source  

SciTech Connect

A rf power system has been developed, which allows the use of rf plasma devices in an electric propulsion test facility without excessive noise pollution in thruster diagnostics. Of particular importance are thrust stand measurements, which were previously impossible due to noise. Three major changes were made to the rf power system: first, the cable connection was changed from a balanced transmission line to an unbalanced coaxial line. Second, the rf power cabinet was placed remotely in order to reduce vibration-induced noise in the thrust stand. Finally, a relationship between transmission line length and rf was developed, which allows good transmission of rf power from the matching network to the helicon antenna. The modified system was tested on a thrust measurement stand and showed that rf power has no statistically significant contribution to the thrust stand measurement.

Kieckhafer, Alexander W.; Walker, Mitchell L. R. [Department of Aerospace Engineering, High-Power Electric Propulsion Laboratory, College of Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2010-07-15T23:59:59.000Z

197

Free electron laser using Rf coupled accelerating and decelerating structures  

DOE Patents (OSTI)

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.

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

198

National rf technology research and development program plan  

Science Conference Proceedings (OSTI)

This plan was prepared by the Oak Ridge National Laboratory at the request of the Office of Fusion Energy, Division of Development and Technology, to define the technology development needs and priorities. The US rf research and development community, with a wide representation from universities, laboratories and industries, participated in many discussions, meetings and in a three-day workshop in developing the needs and priorities definition. This very active and effective involvement of the rf leaders from all of these groups was an essential feature of the activity and results in the plan representing a broad consensus from the magnetic fusion energy development community. In addition, a number of scientists from Japan and Europe participated by providing data.

Not Available

1983-05-01T23:59:59.000Z

199

Design of RF systems for the RTD mission VASIMR  

SciTech Connect

The first flight test of the variable specific impulse magnetoplasma rocket (VASIMR) is tentatively scheduled for the Radiation and Technology Demonstration (RTD) in 2003. This mission to map the radiation environment out to several earth radii will employ both a Hall thruster and a VASIMR during its six months duration, beginning from low earth orbit. The mission will be powered by a solar array providing 12 kW of direct current electricity at 50 V. The VASIMR utilizes radiofrequency (RF) power both to generate a high-density plasma in a helicon source and to accelerate the plasma ions to high velocity by ion cyclotron resonance heating (ICRH). The VASIMR concept is being developed by the National Aeronautics and Space Administration (NASA) in collaboration with national laboratories and universities. Prototype plasma sources, RF amplifiers, and antennas are being developed in the experimental facilities of the Advanced Space Propulsion Laboratory (ASPL). (c) 1999 American Institute of Physics.

Baity, F. W. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Barber, G. C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Carter, M. D. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Goulding, R. H. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Sparks, D. O. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Chang-Diaz, F. R. [Advanced Space Propulsion Laboratory, NASA, Johnson Space Center, Houston, Texas 77059 (United States); McCaskill, G. E. [Advanced Space Propulsion Laboratory, NASA, Johnson Space Center, Houston, Texas 77059 (United States); Squire, J. P. [Advanced Space Propulsion Laboratory, NASA, Johnson Space Center, Houston, Texas 77059 (United States)

1999-09-20T23:59:59.000Z

200

Design of RF Systems for the RTD Mission VASIMR  

SciTech Connect

The first flight test of the variable specific impulse magnetoplasma rocket (VASIMR) is tentatively scheduled for the Radiation and Technology Demonstration (RTD) in 2003. This mission to map the radiation environment out to several earth radii will employ both a Hall thruster and a VASIMR during its six months duration, beginning from low earth orbit. The mission will be powered by a solar array providing 12 kW of direct current electricity at 50 V. The VASIMR utilizes radiofrequency (RF) power both to generate a high-density plasma in a helicon source and to accelerate the plasma ions to high velocity by ion cyclotron resonance heating (ICRH). The VASIMR concept is being developed by the National Aeronautics and Space Administration (NASA) in collaboration with national laboratories and universities. Prototype plasma sources, RF amplifiers, and antennas are being developed in the experimental facilities of the Advanced Space Propulsion Laboratory (ASPL).

Baity, F.W.; Barber, G.C.; Carter, M.D.; Chang-Diaz, F.R.; Goulding, R.H.; McCaskill, G.E.; Sparks, D.O.; Squire, J.P.

1999-04-12T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


201

Resonant ring for testing of accelerator RF windows  

SciTech Connect

A klystron-driven resonant ring has been designed and assembled at the Los Alamos National Laboratory for use in the Accelerator Production of Tritium Project (APT). The ring was built to test rf windows for the 700 MHz section of the APT accelerator. The ring has been designed to apply an effective power of approximately 1 MW on test windows. Details of ring design, operation and performance will be presented.

Gerken, E.; Rees, D.; Roybal, W.; Cummings, K. [Los Alamos National Lab., NM (United States); Gahl, J.M. [Univ. of New Mexico, Albuquerque, NM (United States)

1997-09-01T23:59:59.000Z

202

RF Choke for Standing Wave Structures and Flanges  

DOE Green Energy (OSTI)

SLAC participates in the U.S. High Gradient collaboration whose charter includes basic studies of rf breakdown properties in accelerating structures. These studies include experiments with different materials and construction methods for single cell standing wave accelerating structures. The most commonly used method of joining cells of such structures is the high temperature bonding and/or brazing in hydrogen and/or vacuum. These high temperature processes may not be suitable for some of the new materials that are under consideration. We propose to build structures from cells with an rf choke, taking the cell-to-cell junction out of the electromagnetic field region. These cells may be clamped together in a vacuum enclosure, the choke joint ensuring continuity of rf currents. Next, we propose a structure with a choke joint in a high gradient cell and a view port which may allow us microscopic, in-situ observation of the metal surface during high power tests. And third, we describe the design of a TM01 choke flange for these structures.

Yeremian, Anahid; /SLAC; Dolgashev, Valery; /SLAC; Tantawi, Sami; /SLAC

2012-07-03T23:59:59.000Z

203

Chemical vapor deposition of ZrC in small bore carbon-composite tubes  

SciTech Connect

Process conditions are described for the chemical vapor deposition of ZrC from ZrCl/sub 4/--CH/sub 4/--HCl--H/sub 2/--Ar vapor over the temperature range 1320 to 1775 deg K. From an analysis of the process conditions (initial composition of coating gas, axial temperature profile along the tubes, total pressure, and length of deposition time), the subsequent ZrC coat thickness profiles and thermodynamic data, an equation expressing the variation of the axial rate of ZrC deposition is derived. This expression can be used for the estimation of process conditions required to yield a specified ZrC coat profile. Variations of the chlorine and oxygen contents, lattice pararmeter, microstructure of the ZrC deposit and thermal expansion coefficient as a function of deposition temperature are described. (11 figures, 3 tables) (auth)

Wallace, T.C.

1973-01-01T23:59:59.000Z

204

Atomic-layer-deposited Al2O3 and HfO2 on GaN: A comparative study on interfaces and electrical characteristics  

Science Conference Proceedings (OSTI)

Al"2O"3, HfO"2, and composite HfO"2/Al"2O"3 films were deposited on n-type GaN using atomic layer deposition (ALD). The interfacial layer of GaON and HfON was observed between HfO"2 and GaN, whereas the absence of an interfacial layer at Al"2O"3/GaN ... Keywords: Al2O3, Atomic-layer-deposition (ALD), GaN, HfO2, High k dielectric, MOS

Y. C. Chang; M. L. Huang; Y. H. Chang; Y. J. Lee; H. C. Chiu; J. Kwo; M. Hong

2011-07-01T23:59:59.000Z

205

Diffraction Analysis of Ball Milled Platinum Based Powders (Pt-ZrO2)  

Science Conference Proceedings (OSTI)

... series of powder samples with different amount of ZrO2 and ball milling time were examined by the synchrotron radiation at Brookhaven National Laboratory.

206

Continuous Casting and Product Characterization of Al-Mg-Sc-Zr ...  

Science Conference Proceedings (OSTI)

These improvements lead quaternary Al-Mg-Sc-Zr alloys to be important ... Frequency Modulation Effect on the Solidification of Alloy 718 Fusion Zone.

207

Oxidation Resistance of Zr- and Ti- Based Bulk Metallic Glasses in ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Bulk Metallic Glasses IX. Presentation Title, Oxidation Resistance of Zr- and ...

208

Study on Heteropolyacids/Ti/Zr Mixed in the Inorganic Composites ...  

Science Conference Proceedings (OSTI)

Symposium, Energy Conversion/Fuel Cells. Presentation Title, Study on Heteropolyacids/Ti/Zr Mixed in the Inorganic Composites for Fuel Cell Electrolytes.

209

g-factor of the 2{sup+}{sub{1} state of {sup179}Hf.  

SciTech Connect

The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +}) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

Berant, Z.; Oster, E.; Wolf, A.; Casperson, R. J.; Werner, V.; McCutchan, E. A. (Physics); (Yale Univ.); (Nuclear Research Center Negev); (Rutgers Univ.); (Clark Univ.); (Univ. of Richmond); (Univ. of Surrey); (Rhodes Coll.); (Technische Univ. Darmstadt); (ENS CACHAN)

2009-01-01T23:59:59.000Z

210

g factor of the 2{sub 1}{sup +} state of {sup 172}Hf  

Science Conference Proceedings (OSTI)

The g factor of the 2{sub 1}{sup +} state of {sup 172}Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2{sub 1}{sup +})=0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data.

Berant, Z.; Wolf, A. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Nuclear Research Center Negev, Beer-Sheva 84190 (Israel); Oster, E. [Nuclear Research Center Negev, Beer-Sheva 84190 (Israel); Casperson, R. J.; Werner, V.; Heinz, A.; Casten, R. F.; Terry, J. R.; Winkler, R.; Williams, E.; Qian, J.; Schmidt, A.; Smith, M. K.; Ahn, T. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Gurdal, G. [Rutgers University, New Brunswick, New Jersey 08903 (United States); McCutchan, E. A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Brenner, D. S. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Chemistry Department, Clark University, Worcester, Massachusetts 01610 (United States); Beausang, C. W. [Physics Department, University of Richmond, Richmond, Virginia 23173 (United States); Regan, P. H. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Ross, T. [Physics Department, University of Richmond, Richmond, Virginia 23173 (United States); Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)] (and others)

2009-11-15T23:59:59.000Z

211

RF system models for the CERN Large Hadron Collider with application to longitudinal dynamics  

Science Conference Proceedings (OSTI)

The LHC RF station-beam interaction strongly influences the longitudinal beam dynamics, both single bunch and collective effects. Non-linearities and noise generated within the Radio Frequency (RF) accelerating system interact with the beam and contribute to beam motion and longitudinal emittance blowup. Thus, the noise power spectrum of the RF accelerating voltage strongly affects the longitudinal beam distribution. Furthermore, the coupled-bunch instabilities are also directly affected by the RF components and the configuration of the Low Level RF (LLRF) feedback loops. In this work we present a formalism relating the longitudinal beam dynamics with the RF system configurations, an estimation of collective effects stability margins, and an evaluation of longitudinal sensitivity to various LLRF parameters and configurations.

Mastorides, T.; Rivetta, C.; Fox, J.D.; Winkle, D.Van; /SLAC; Baudrenghien, P.; /CERN

2011-03-03T23:59:59.000Z

212

Current Patterns on the West Florida Shelf from Joint Self-Organizing Map Analyses of HF Radar and ADCP Data  

Science Conference Proceedings (OSTI)

To assess the spatial structures and temporal evolutions of distinct physical processes on the West Florida Shelf, patterns of ocean current variability are extracted from a joint HF radar and ADCP dataset acquired from August to September 2003 ...

Yonggang Liu; Robert H. Weisberg; Lynn K. Shay

2007-04-01T23:59:59.000Z

213

The Influence of Fetch on the Response of Surface Currents to Wind Studied by HF Ocean Surface Radar  

Science Conference Proceedings (OSTI)

The momentum transfer from wind to sea generates surface currents through both the wind shear stress and the Stokes drift induced by waves. This paper addresses issues in the interpretation of HF radar measurements of surface currents and ...

Yadan Mao; Malcolm L. Heron

2008-05-01T23:59:59.000Z

214

Tests of Long-Range Ocean Data Telemetry Using Frequency-Agile HF Packet-switching Protocols  

Science Conference Proceedings (OSTI)

Experiences with two prototype telemetry systems developed for potential use with moored or drifting ocean instruments are described. The systems transfer data and commands between remote and base stations using direct high-frequency (HF) ...

David A. Brooks; Melbourne G. Briscoe

1991-12-01T23:59:59.000Z

215

Thermodynamic Modeling and Experimental Study of the Fe-Cr-Zr System  

Science Conference Proceedings (OSTI)

Wide applications of zircaloys, stainless steels and their interactions in nuclear reactors require the knowledge on phase stability and thermodynamic property of the Fe-Cr-Zr system. This knowledge is also important to develop new Zr-contained Fe-Cr ferritic steels. This work aims at developing thermodynamic models for describing phase stability and thermodynamic property of the Fe-Cr-Zr system using the Calphad approach coupled with experimental study. Thermodynamic descriptions of the Fe-Cr and Cr-Zr systems were either directly adopted or slightly modified from literature. The Fe-Zr system has been remodeled to accommodate recent ab-initio calculation of formation enthalpies of various Fe-Zr compounds. Reliable ternary experimental data and thermodynamic models were mainly available in the Zr-rich region. Therefore, selected ternary alloys located in the vicinity of the eutectic valley of (Fe,Cr,Zr) and (Fe,Cr)2Zr laves phase in the Fe-rich region have been experimentally investigated in this study. Microstructure has been examined by using scanning electron microscope, energy-dispersive Xray spectroscopy and X-ray diffraction. These experimental results, along with the literature data were then used to develop thermodynamic models for phases in the Fe-Cr-Zr system. Calculated phase equilibria and thermodynamic properties of the ternary system yield satisfactory agreements with available experimental data, which gives the confidence to use these models as building blocks for developing a Zr, Fe and Cr contained multicomponent thermodynamic database for broader applications in nuclear reactors.

Yang, Ying [ORNL; Tan, Lizhen [ORNL; Bei, Hongbin [ORNL; Busby, Jeremy T [ORNL

2013-01-01T23:59:59.000Z

216

Non-molecular Phases of H2O and HF Under Detonation-like Conditions  

DOE Green Energy (OSTI)

Energetic materials are known to produce simple molecular species, such as HF and H{sub 2}O, during detonation. The behavior of such species under conditions of simultaneous high pressure and temperature are unknown. The predicted high pressure superionic phases of water and HF are investigated via ab initio molecular dynamics. We study water at densities of 2.0-3.0 g/cc (34 -115 GPa) along the 2000 K isotherm. We find that extremely rapid (superionic) diffusion of protons occurs in a fluid phase at pressures between 34 and 58 GPa. A transition to a stable body-centered cubic (bcc) O lattice with superionic proton conductivity is observed between 70 and 75 GPa. We find that all molecular species at pressures greater than 75 GPa are too short lived to be classified as bound states. Up to 95 GPa, we find a solid superionic phase characterized by covalent O-H bonding. Above 95 GPa, a transient network phase is found characterized by symmetric O-OH hydrogen bonding with nearly 50% covalent character. Ab initio molecular dynamics H simulations of HF were conducted at densities of 1.8-4.0 g/cc along the 900 K isotherm. According to our simulations, a unique form of (symmetric) hydrogen bonding could play a significant role in superionic conduction. Our work shows that the Chapman-Jouget and Zeldovich-von Neumann Doring (ZND) states of some energetic materials are close to the molecular to non-molecular transition.

Fried, L E; Goldman, N; Kuo, I W; Mundy, C J

2006-07-10T23:59:59.000Z

217

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

DOE Patents (OSTI)

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.

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

2013-01-15T23:59:59.000Z

218

Production and decay properties of the 1.9-s isomeric state in {sup 261}Rf  

SciTech Connect

The 1.9-s isomeric state ({sup 261}Rf{sup b}) in {sup 261}Rf was directly populated in the {sup 248}Cm({sup 18}O,5n){sup 261}Rf{sup b} reaction. Alpha and spontaneous fission (SF) decays of {sup 261}Rf{sup b}, as well as the 68-s state {sup 261}Rf{sup a}, was investigated with a rotating wheel apparatus under low background conditions attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. An identification of {sup 261}Rf{sup b} was based on {alpha}-{alpha} correlations linking {alpha} decays of {sup 261}Rf{sup b} and its daughter {sup 257}No. The {alpha}-particle energy of {sup 261}Rf{sup b} was measured to be 8.52 {+-} 0.05 MeV. The half-life was determined to be 1.9 {+-} 0.4 s based on both 8.52-MeV {alpha} and SF decays. The {alpha} and SF branches are 0.27 {+-} 0.06 and 0.73 {+-} 0.06, respectively. The cross section for the {sup 248}Cm({sup 18}O,5n){sup 261}Rf{sup b} reaction is {sigma}({sup 261}Rf{sup b}) = 11 {+-} 2 nb at 95.1 MeV, which gives a cross-section ratio of {sigma}({sup 261}Rf{sup a})/{sigma}({sup 261}Rf{sup b}) = 1.1 {+-} 0.2.

Haba, H.; Kaji, D.; Kikunaga, H.; Kudou, Y.; Morimoto, K.; Morita, K.; Ozeki, K.; Sumita, T.; Yoneda, A.; Kasamatsu, Y.; Komori, Y.; Ooe, K.; Shinohara, A. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2011-03-15T23:59:59.000Z

219

Surface Characterization of the LCLS RF Gun Cathode  

Science Conference Proceedings (OSTI)

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.

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

220

Capacitively coupled RF voltage probe having optimized flux linkage  

DOE Patents (OSTI)

An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Moore, James A. (Powell, TN); Sparks, Dennis O. (Maryville, TN)

1999-02-02T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Optical Emission of Dusty RF Discharges: Experiment and Simulation  

Science Conference Proceedings (OSTI)

The spectral emission of argon atoms in a dusty radio frequence (RF) discharge has been investigated experimentally and in simulations. It was observed that the spatially and temporally resolved emission of the argon atoms in the dusty discharge was increased compared to the dust-free case during sheath expansion. The corresponding simulations have revealed that the dust trapped in the sheath of the discharge leads to a small, but important, increase of the amount of high-energy electrons that in turn leads to an increased argon emission.

Melzer, A.; Lewerentz, L.; Schneider, R. [Institute of Physics, University Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Huebner, S. [Institute of Physics, University Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Department of Applied Physics, Technical University Eindhoven, NL-5600 MB Eindhoven (Netherlands); Matyash, K. [Max-Planck-Institute for Plasma Physics, EURATOM Association, D-17491 Greifswald (Germany); Ikkurthi, V. R. [Institute for Plasma Research, Bhat, Ghandinagar, Gujarat (India)

2011-11-29T23:59:59.000Z

222

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

DOE Green Energy (OSTI)

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.

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

223

Nitric Acid Oxidized ZrO$_2$ as the Tunneling Oxide of Cobalt Silicide Nanocrystal Memory Devices  

Science Conference Proceedings (OSTI)

In this study, ZrO$_2$ formed by the nitric acid oxidation method is proposed to be the tunneling oxide for nonvolatile memory device applications. The sputtered Zr thin film was oxidized ...

Chih-Wei Hu; Ting-Chang Chang; Chun-Hao Tu; Yang-Dong Chen; Chao-Cheng Lin; Min-Chen Chen; Jian-Yang Lin; Simon M. Sze; Tseung-Yuen Tseng

2011-09-01T23:59:59.000Z

224

Field Emission Cathode Gating for RF Electron Guns (IN-04-039)  

Scientists at Argonne National Laboratory have created an innovative way to enhance the performance of radio frequency (RF) electron guns: a method of ...

225

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

SciTech Connect

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.

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

2012-03-01T23:59:59.000Z

226

High-field superconductivity in some bcc Ti-Mo and Nb-Zr alloys  

Science Conference Proceedings (OSTI)

Zero electrical resistance at unusually high magnetic field strengths has been observed in the bcc alloys Ti-16 a/o (atomic percent) Mo, Nb-12 a/o Zr, and Nb-25 a/o Zr. The maximum highfield zero-resistance current density, Jc, in these ...

R. R. Hake; T. G. Berlincourt; D. H. Leslie

1962-01-01T23:59:59.000Z

227

Amorphous W-Zr films as diffusion barriers between Al and Si  

SciTech Connect

Cosputtered W70Zr30 and W40Zr60 films are investigated as diffusion barriers between Aq and Si. W-Zr alloys of both compositions were determined by x-ray diffraction to crystallize at 900/sup 0/C on A1/sub 2/O/sub 3/ substrates. On <111>Si the W-Zr alloy reacts with the substrate above 700/sup 0/C, forming a uniform, polycrystalline layer of W and Zr silicides. Despite the high crystallization temperatures, an A1 overlayer interacts with W-Zr and the Si substrate at approx. 500/sup 0/C. MeV He-backscattering spectrometry, SEM, and EDAX indicate that this reaction is laterally nonuniform with the formation of deep pits penetrating into the Si substrate. The authors believe this to be a consequence of fractures in the W-Zr layer induced by reaction with A1. Electrical measurements on shallow junction diodes with /W-Zr/Al contacts show that the device junctions were thermally stable after a 30 min annealing at 450/sup 0/C but were all shorted after heat treatments at 500/sup 0/C or above.

So, F.T.; Zhao, X.A.; Kolawa, E.; Tandon, J.L.; Zhu, M.F.

1986-01-01T23:59:59.000Z

228

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

NLE Websites -- All DOE Office Websites (Extended Search)

RF RF [ICO] Name Last modified Size Description [DIR] Parent Directory - [ ] 0D8C3B68.pdf 08-May-2003 07:16 60K [ ] 0D8C3B68 Driver Kaptons.PDF 08-May-2003 07:16 69K [ ] 2002-10-28 - FMIT-3 Tuning to 78 MHZ.pdf 08-May-2003 07:16 425K [ ] FMIT 1 Crowb-et Access.pdf 08-May-2003 07:16 38K [ ] FMIT 1 Trans-cess.doc..pdf 08-May-2003 07:16 38K [ ] FMIT 1 Transformer Entry.pdf 08-May-2003 07:16 46K [ ] FMIT 2 Crowba-et access.pdf 08-May-2003 07:16 38K [ ] FMIT 2 Trans-cess.doc..pdf 08-May-2003 07:16 38K [ ] FMIT 2 Transformer Entry.pdf 08-May-2003 07:16 46K [ ] FMIT 3 Crowb-et Access.pdf 08-May-2003 07:16 38K [ ] FMIT 3 Trans-et Access.pdf 08-May-2003 07:16 38K [ ] FMIT 4 Crowb-et Access.pdf 08-May-2003 07:16 38K

229

Plasma properties of RF magnetron sputtering system using Zn target  

Science Conference Proceedings (OSTI)

In the present work, we investigate the fundamental properties of magnetron sputtering plasma using Zn target and its deposited Zn thin film. The magnetron sputtering plasma was produced using radio frequency (RF) power supply and Argon (Ar) as ambient gas. A Langmuir probe was used to collect the current from the plasma and from the current intensity, we calculate the electron density and electron temperature. The properties of Zn sputtering plasma at various discharge conditions were studied. At the RF power ranging from 20 to 100 W and gas pressure 5 mTorr, we found that the electron temperature was almost unchanged between 2-2.5 eV. On the other hand, the electron temperature increased drastically from 6 Multiplication-Sign 10{sup 9} to 1 Multiplication-Sign 10{sup 10}cm{sup -3} when the discharge gas pressure increased from 5 to 10 mTorr. The electron microscope images show that the grain size of Zn thin film increase when the discharge power is increased. This may be due to the enhancement of plasma density and sputtered Zn density.

Nafarizal, N.; Andreas Albert, A. R.; Sharifah Amirah, A. S.; Salwa, O.; Riyaz Ahmad, M. A. [Microelectronic and Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

2012-06-29T23:59:59.000Z

230

High Gradient Operation with the CEBAF Upgrade RF Control System  

SciTech Connect

The CEBAF Accelerator at Jefferson Lab is presently a 6 GeV five pass electron accelerator consisting of two superconducting linacs joined by independent magnetic transport arcs. Energy will be upgraded to 12 GeV with the addition of 10 new high gradient cryomodules (17+ MV/m). The higher gradients pose significant challenges beyond what the present analog low level RF (LLRF) control systems can handle reliably; therefore, a new LLRF control system is needed. A prototype system has been developed incorporating a large FPGA and using digital down and up conversion to minimize the need for analog components. The new system is more flexible and less susceptible to drifts and component nonlinearities. Because resonance control is critical to reach high gradients quickly, the new cryomodules will include a piezoelectric tuner for each cavity, and the LLRF controls must incorporate both feedback and feed-forward methods to achieve optimal resonance control performance. This paper discusses development of the new RF system, system performance for phase and amplitude stability and resonance control under Lorentz detuning measured during recent tests on a prototype cryomodule.

J. Hovater; G. Davis; Hai Dong; Alicia Hofler; Lawrence King; John Musson; Tomasz Plawski

2006-08-16T23:59:59.000Z

231

Proposal of an Arc Detection Technique Based on RF Measurements for the ITER ICRF Antenna  

SciTech Connect

RF arc detection is a key operational and safety issue for the ICRF system on ITER. Indeed the high voltages inside the antenna put it at risk of arcing, which could cause substantial damage. This paper describes the various possibilities explored by circuit simulation and the strategy now considered to protect the ITER ICRF antenna from RF arcs.

Huygen, S.; Dumortier, P.; Durodie, F.; Messiaen, A.; Vervier, M.; Vrancken, M. [LPP/ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Wooldridge, E. [EURATOM/CCFE Fusion Association, Culham Science Centre (United Kingdom)

2011-12-23T23:59:59.000Z

232

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

E-Print Network (OSTI)

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

Artuso, Florinda

233

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

E-Print Network (OSTI)

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

Stancil, Daniel D.

234

RF Breakdown Studies Using a 1.3 GHZ Test Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R.P.; Neubauer, M.; /Muons Inc., Batavia; Conde, M.; Gai, W.; /Argonne; Moretti, A.; Popovic, M.; Yonehara, K.; /Fermilab; Byrd, J.; Li, D.; /LBL, Berkeley; BastaniNejad, M.; /Old Dominion U.

2009-05-01T23:59:59.000Z

235

RF Breakdown Studies Using a 1.3-GHz Text Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R. P.; Neubauer, M.; Conde, M.; Gai, W.; Moretti, A.; Popovic, M.; Yonehara, K.; Byrd, J.; Li, D.; BastaniNejad, M.; Elmustafa, M.

2009-05-04T23:59:59.000Z

236

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

DOE Patents (OSTI)

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.

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

237

1.3 GHz superconducting RF cavity program at Fermilab  

SciTech Connect

At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules (CMs) for Project X, an International Linear Collider (ILC), or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.

Ginsburg, C.M.; Arkan, T.; Barbanotti, S.; Carter, H.; Champion, M.; Cooley, L.; Cooper, C.; Foley, M.; Ge, M.; Grimm, C.; Harms, E.; /Fermilab

2011-03-01T23:59:59.000Z

238

Cerenkov Radiator Driven by a Superconducting RF Electron Gun  

SciTech Connect

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.

Poole, B R; Harris, J R

2011-03-07T23:59:59.000Z

239

GaAs Films Prepared by RF-Magnetron Sputtering  

DOE Green Energy (OSTI)

The authors reported on the optical absorption, adhesion, and microstructure of RF-magnetron sputtered films of hydrogenated amorphous and microcrystalline GaAs films for the 1 to 25 {micro}m infrared wavelength rate. Sputtering parameters which were varied include sputtering power, temperature and pressure, and hydrogen sputtering-gas concentration. TEM results show a sharp transition from purely amorphous GaAs to a mixture of microcrystalline GaAs in an amorphous matrix at 34 {+-} 2 C. By optimizing the sputtering parameters, the optical absorption coefficient can be decreased below 100 cm{sup -1} for wavelengths greater than about 1.25 {micro}m. These results represent the lowest reported values of optical absorption for sputtered films of GaAs directly measured by spectrophotometry for the near-infrared wavelength region.

L.H. Ouyang; D.L. Rode; T. Zulkifli; B. Abraham-Shrauner; N. Lewis; M.R. Freeman

2001-08-01T23:59:59.000Z

240

Active RF Pulse Compression Using An Electrically Controlled Semiconductor Switch  

SciTech Connect

First we review the theory of active pulse compression systems using resonant delay lines. Then we describe the design of an electrically controlled semiconductor active switch. The switch comprises an active window and an overmoded waveguide three-port network. The active window is based on a four-inch silicon wafer which has 960 PIN diodes. These are spatially combined in an overmoded waveguide. We describe the philosophy and design methodology for the three-port network and the active window. We then present the results of using this device to compress 11.4 GHz RF signals with high compression ratios. We show how the system can be used with amplifier like sources, in which one can change the phase of the source by manipulating the input to the source. We also show how the active switch can be used to compress a pulse from an oscillator like sources, which is not possible with passive pulse compression systems.

Guo, Jiquan; Tantawi, Sami; /SLAC

2007-01-10T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Microsoft PowerPoint - IPRC 2012-Zr behavior  

NLE Websites -- All DOE Office Websites (Extended Search)

Behavior Behavior of Zirconium Oxide and Zirconium Metal in a LiCl-Li 2 O-Based Electrolytic Reduction System S. D. Herrmann, L. A. Wurth, N. J. Gese August 27, 2012 2012 International Pyroprocessing Research Conference The Abbey Resort Fontana, Wisconsin Introduction  Background - An electrometallurgical treatment process has been operating since 1996 to treat 25 MTHM of sodium-bonded uranium metal blanket and uranium metal alloy driver fuel from Experimental Breeder Reactor - II (EBR-II) at Idaho National Laboratory's Fuel Conditioning Facility. - In the course of retrieving EBR-II spent driver fuel for treatment, a significant quantity of degraded U-10Zr spent fuels, i.e., breached fuel exposed to air, has accumulated since 1996. - As oxidized material, it would require head-end treatment prior to electrorefining. - Electrolytic reduction is a candidate head-end treatment

242

The analysis of Ytrium doped BaZrO3  

Office of Scientific and Technical Information (OSTI)

Project Title: Enhanced Power Stability for Proton Conducting Solid Oxides Fuel Cells Project Title: Enhanced Power Stability for Proton Conducting Solid Oxides Fuel Cells Report Title: Computational modeling, synthesis, and characterization of BaZr 1-x Y x O 3-δ solid state proton conductor. Type of Report: Semi-Annual Technical Progress Report Reporting Period Start Date: March 30, 2003 Reporting Period End Date: September 30, 2003 Principle Authors: Boris Merinov, Claudio O. Dorso, William A. Goddard III, Jian Wu, and Sossina Haile Date Report was Issued: October 30, 2003 DOE Award Number: DE-FC26-02NT41631 Name and Address of Submitting Organization: California Institute of Technology, mail code 139- 74, 1200 E. California Blvd., Pasadena, CA 91125 1 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States

243

SLAC collider injector, RF-drive synchronization and trigger electronics, and 15-AMP thermionic-gun development  

SciTech Connect

The rf drive system for the Collider Injector Development (EL CID) including laser timing, subharmonic buncher drive and phasing, and accelerator rf drive is described. The rf synchronized master trigger generation scheme for the collider is outlined. Also, a 15 amp peak, 200 kV short pulse gun being developed at SLAC as a backup to the Sinclair laser gun is described.

Koontz, R.; Miller, R.; McKinney, T.; Wilmunder, A.

1981-02-01T23:59:59.000Z

244

VFL-HF heating of the lower ionosphere and ELF wave generation  

SciTech Connect

For incident wave power densities of 10{sup {minus}6} {minus} 10{sup {minus}2} W/m{sup 2} (at 30 km altitude), VLF heating of the D-region (< 90 km) is found to be 2-10 times more effective (depending on power) than HF heating, resulting in comparable perturbations of subionospheric VLF probe waves in spite of up to 10{sup 3} times larger power density utilized in HF heating and at least as efficient in ELF wave generation. In view of generally larger (100 {times} 100 km) area of the ionosphere illuminated by VLF transmitters, ELF wave generation by modulated VLF heating is estimated to produce ELF power levels of {approximately}100 mW, comparable with or larger than those produced in typical midlatitude ambient ionosphere occurs primarily via the modulation of Pedersen current whereas in a typical auroral ionosphere Hall current is dominant for pump wave frequencies up to {approximately}6 MHz. For 10-30 MHz and power densities > 10{sup {minus}4} W/m{sup 2}, Pedersen current modulation is again dominant, potentially providing up to 2-15 times higher ELF dipole moment than those found in recent experiments using 3-5 MHz heaters.

Taranenko, Y.N.; Inan, U.S.; Bell, T.F. (Stanford Univ., CA (United States))

1992-01-03T23:59:59.000Z

245

Plasma and vacuum ultraviolet induced charging of SiO{sub 2} and HfO{sub 2} patterned structures  

SciTech Connect

The authors compare the effects of plasma charging and vacuum ultraviolet (VUV) irradiation on oxidized patterned Si structures with and without atomic-layer-deposited HfO{sub 2}. It was found that, unlike planar oxidized Si wafers, oxidized patterned Si wafers charge up significantly after exposure in an electron-cyclotron resonance plasma. The charging is dependent on the aspect ratio of the patterned structures. This is attributed to electron and/or ion shading during plasma exposure. The addition of a 10 nm thick HfO{sub 2} layer deposited on top of the oxidized silicon structures increases the photoemission yield during VUV irradiation, resulting in more trapped positive charge compared to patterns without the HfO{sub 2} dielectric.

Lauer, J. L.; Upadhyaya, G. S.; Sinha, H.; Kruger, J. B.; Nishi, Y.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Stanford Nanofabrication Facility, Stanford University, Stanford, California 94303 (United States); Stanford University, Stanford, California 94305 (United States); Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2012-01-15T23:59:59.000Z

246

Radio-Frequency (RF) Devices for Safeguards: Where We Are and Where We Need to Go  

Science Conference Proceedings (OSTI)

Radio-Frequency (RF) devices have revolutionized many aspects of modern industrial processes. RF technology can enable wireless communication for tag identification, sensor communication, and asset tracking. Radio-frequency identification (RFID) is a technology that utilizes wireless communication to interrogate and identify an electronic tag attached to an item in order to identify the item. The technology can come in many forms: passive or active tags, low to ultra-wideband frequencies, small paper-thin tags to brick-sized units, and simple tags or highly integrated sensor packages. RF technology, and specifically RFID, has been applied widely in commercial markets for inventory, supply chain management, and asset tracking. Several recent studies have demonstrated the safeguards benefits of utilizing RFID versus conventional inventory tagging methods for tracking nuclear material. These studies have indicated that the RF requirements for safeguards functions are more stringent than the RF requirements for other inventory tracking and accounting applications. Additionally, other requirements must be addressed, including environmental and operating conditions, authentication, and tag location and attachment. Facility restrictions on radio spectrum, method of tag attachment, and sensitivity of the data collected impact the tag selection and system design. More important, the intended use of the system must be considered. The requirements for using RF to simply replace or supplement container identifiers such as bar codes that facilitate the inventory function will differ greatly from the requirements for deploying RF for unattended monitoring applications. Several studies have investigated these considerations to advance commercial RF devices for safeguards use, and a number of system concepts have been developed. This paper will provide an overview of past studies and current technologies, and will investigate the requirements, existing gaps, and several potential next steps for advancing RF techniques for safeguards use.

Rowe, Nathan C [ORNL; Younkin, James R [ORNL; Pickett, Chris A [ORNL; Whitaker, J Michael [ORNL

2011-01-01T23:59:59.000Z

247

Model for Simulation of Hydride Precipitation in Zr-Based Used Fuel  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

for Simulation of Hydride Precipitation in Zr-Based Used Fuel for Simulation of Hydride Precipitation in Zr-Based Used Fuel Claddings: A Status Report on Current Model Capabilities Model for Simulation of Hydride Precipitation in Zr-Based Used Fuel Claddings: A Status Report on Current Model Capabilities The report demonstrates a meso-scale, microstructural evolution model for simulation of zirconium hydride precipitation in the cladding of used fuels during long-term dry-storage. While the Zr-based claddings (regarded as a barrier for containment of radioactive fission products and fuel) are manufactured free of any hydrogen, they absorb hydrogen during service in the reactor. The amount of hydrogen that the cladding picks up is primarily a function of the exact chemistry and microstructure of the claddings and reactor operating conditions, time-temperature history, and

248

Oxidation Behavior of Arc Melted ZrB 2 -SiC Composite  

Science Conference Proceedings (OSTI)

Conventional microstructure of ZrB2-SiC is particulate structure i.e. SiC forms a network that is interconnected in three dimensions. During the ...

249

Catalytic activity of ZrO2 nanotube arrays prepared by anodization method  

Science Conference Proceedings (OSTI)

ZrO2 nanotube arrays were prepared by anodization method in aqueous electrolyte containing (NH4)2SO4 and NH4F. The morphology and structure of nanotube arrays were characterized through scanning ...

Xixin Wang; Jianling Zhao; Xiaorui Hou; Qi He; Chengchun Tang

2012-01-01T23:59:59.000Z

250

Instrumental Uncertainties in Z–R Relationships and Raindrop Fall Velocities  

Science Conference Proceedings (OSTI)

This study demonstrates the sensitivity of reflectivity–rainfall rate (Z–R) relationships, which were derived from disdrometer-based drop size distribution measurements, to the fall velocity of the drops. The dataset used comes from the ...

Christian Salles; Jean-Dominique Creutin

2003-02-01T23:59:59.000Z

251

A Field Study of Reflectivity and Z–R Relations Using Vertically Pointing Radars and Disdrometers  

Science Conference Proceedings (OSTI)

Observations from a 16-month field study using two vertically pointing radars and a disdrometer at Wallops Island are analyzed to examine the consistency of the multi-instrument observations with respect to reflectivity and Z–R relations. The ...

Ali Tokay; Peter Hartmann; Alessandro Battaglia; Kenneth S. Gage; Wallace L. Clark; Christopher R. Williams

2009-06-01T23:59:59.000Z

252

Comparison of WPMM versus Regression for Evaluating Z–R Relationships  

Science Conference Proceedings (OSTI)

The accuracy of the estimation of Z–R relationships is evaluated for the Window Probability Matching Method (WPMM) and regression methods. The evaluation is based on experiments of random subsampling of disdrometer-obtained 1-min reflectivity Z ...

Daniel Rosenfeld; Eyal Amitai

1998-10-01T23:59:59.000Z

253

Exploring the Transient Behavior of Z–R Relationships: Implications for Radar Rainfall Estimation  

Science Conference Proceedings (OSTI)

The objective of this study is to characterize the signature of dynamical microphysical processes on reflectivity–rainfall (Z–R) relationships used for radar rainfall estimation. For this purpose, a bin model with explicit microphysics was used ...

Olivier P. Prat; Ana P. Barros

2009-10-01T23:59:59.000Z

254

Sensitivity of the Estimated Monthly Convective Rain Fraction to the Choice of Z–R Relation  

Science Conference Proceedings (OSTI)

This study investigates the sensitivity of the estimated monthly convective rain fraction—that is, the percentage of the areal rain accumulation contributed by precipitation identified as convective—to variations of the Z–R parameters used in ...

Matthias Steiner; Robert A. Houze Jr.

1997-05-01T23:59:59.000Z

255

In Situ Study of Radiation Damage in Pure Zr and Zircaloy-2  

Science Conference Proceedings (OSTI)

Presentation Title, In Situ Study of Radiation Damage in Pure Zr and Zircaloy-2 ... cascades at the early stages of damage development at very low dose (0.01 ...

256

Resistance Micro-seam Welding of Zr Based Glassy Alloy Foils  

Science Conference Proceedings (OSTI)

EPRI P87, A New Filler Material for Dissimilar Metal Welds · Explosive Bonding of 316L to C18150 CuCrZr Alloy for ITER Applications · Failure Mechanisms of ...

257

Approximate Integrals of rf-driven Particle Motion in Magnetic Field  

DOE Green Energy (OSTI)

For a particle moving in nonuniform magnetic field under the action of an rf wave, ponderomotive effects result from rf-driven oscillations nonlinearly coupled with Larmor rotation. Using Lagrangian and Hamiltonian formalism, we show how, despite this coupling, two independent integrals of the particle motion are approximately conserved. Those are the magnetic moment of free Larmor rotation and the quasi-energy of the guiding center motion parallel to the magnetic field. Under the assumption of non-resonant interaction of the particle with the rf field, these integrals represent adiabatic invariants of the particle motion.

I.Y. Dodin; N.J. Fisch

2004-04-26T23:59:59.000Z

258

Phase Stability and Thermodynamic Assessment of the Np-Zr system  

E-Print Network (OSTI)

Metallic fuels have an important role to play in "fast breeder" Gen-IV type nuclear reactors, and U-Pu-Zr is one of the prototypical systems. Because of the variability in fuel chemistry during burn-up, it is important to understand the effect 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/ 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-ASA-CPA electronic-structure method and lattice stabilities of solution phases obtained from first-principles technique. Another important feature in the Np-Zr alloy system is the non-stoichiometric delta-NpZr2 phase that forms in a hexagonal C32 structure similar to the delta-phase in the U-Zr system and the w-phase in pure Zr. An increase in the homogeneity range of the delta-phase when going from Pu to Np and to U is attributed to a lowering of its heat of formation that is caused by an increase in d-band occupation. Two different possibilities for the stability of the delta- and w- phases have been proposed in the present work. Additionally, calculated changes in enthalpy versus temperature are plotted for two alloy compositions of the Np-Zr system to guide future experimental work in resolving important issues in this system. Finally, an ab initio study, implemented with the L(S)DA U formalism, is performed for pure Np that reveals a transition from a non-magnetic to a magnetic state at a critical U parameter.

Bajaj, Saurabh

2010-12-01T23:59:59.000Z

259

Characterization of TiOxNy nanoparticles embedded in HfOxNy as charge trapping nodes for nonvolatile memory device applications  

Science Conference Proceedings (OSTI)

Silicon-oxide-nitride-oxide-silicon devices with nanoparticles (NPs) as charge trapping nodes (CTNs) are important to provide enhanced performance for nonvolatile memory devices. To study these topics, the TiO"xN"y metal oxide NPs embedded in the HfO"xN"y ... Keywords: Charge trapping nodes, HfOxNy, Nanoparticles, Nonvolatile memory devices, TiOxNy

Chien-Wei Liu; Chin-Lung Cheng; Kuei-Shu Chang-Liao; Jin-Tsong Jeng; Bau-Tong Dai; Chen-Pang Tsai

2009-07-01T23:59:59.000Z

260

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

Science Conference Proceedings (OSTI)

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.

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

2005-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

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

Science Conference Proceedings (OSTI)

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.

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

2005-06-01T23:59:59.000Z

262

Portsmouth DUF6 Conversion Final EIS - Appendix E: Impacts Associated with HF and CaF2 Conversion Product Sale and Use  

NLE Websites -- All DOE Office Websites (Extended Search)

Portsmouth DUF Portsmouth DUF 6 Conversion Final EIS APPENDIX E: IMPACTS ASSOCIATED WITH HF AND CaF 2 CONVERSION PRODUCT SALE AND USE HF and CaF 2 Conversion Products E-2 Portsmouth DUF 6 Conversion Final EIS HF and CaF 2 Conversion Products E-3 Portsmouth DUF 6 Conversion Final EIS APPENDIX E: IMPACTS ASSOCIATED WITH HF AND CaF 2 CONVERSION PRODUCT SALE AND USE E.1 INTRODUCTION During the conversion of the depleted uranium hexafluoride (DUF 6 ) inventory to depleted uranium oxide, products having some potential for sale to commercial users would be produced. These products would include aqueous hydrogen fluoride (HF) and calcium fluoride (CaF 2 , commonly referred to as fluorspar). These products are routinely used as commercial materials, and an investigation into their potential reuse was done; results are included as part of

263

Paducah DUF6 Conversion Final EIS - Appendix E: Impacts Associated with HF and CaF2 Conversion Product Sale and Use  

NLE Websites -- All DOE Office Websites (Extended Search)

Paducah DUF Paducah DUF 6 Conversion Final EIS APPENDIX E: IMPACTS ASSOCIATED WITH HF AND CaF 2 CONVERSION PRODUCT SALE AND USE HF and CaF 2 Conversion Products E-2 Paducah DUF 6 Conversion Final EIS HF and CaF 2 Conversion Products E-3 Paducah DUF 6 Conversion Final EIS APPENDIX E: IMPACTS ASSOCIATED WITH HF AND CaF 2 CONVERSION PRODUCT SALE AND USE E.1 INTRODUCTION During the conversion of the depleted uranium hexafluoride (DUF 6 ) inventory to depleted uranium oxide, products having some potential for sale to commercial users would be produced. These products would include aqueous hydrogen fluoride (HF) and calcium fluoride (CaF 2 , commonly referred to as fluorspar). These products are routinely used as commercial materials, and an investigation into their potential reuse was done; results are included as part of

264

Dynamics of Flat Bunches with Second Harmonic RF  

Science Conference Proceedings (OSTI)

We investigate the dynamics of longitudinally flat bunches created with a second harmonic cavity in a high energy collider. We study Landau damping in a second harmonic cavity with analytical and numerical methods. The latter include particle tracking and evolution of the phase space density. The results are interpreted in the context of possible application to the LHC. A possible path to a luminosity upgrade at the LHC is through the creation of longitudinally flat bunches. They can increase the luminosity roughly by 40% when the beam intensities are at the beam-beam limit. Lower momentum spread which can reduce backgrounds and make collimation easier as well lower peak fields which can mitigate electron cloud effects are other advantages. Use of a second harmonic rf system is a frequently studied method to create such flat bunches. Here we consider some aspects of longitudinal dynamics of these bunches in the LHC at top energy. First we consider intensity limits set by the loss of Landau damping against rigid dipole oscillations. Next we describe numerical simulations using both particle tracking and evolution of the phase space density. These simulations address the consequences of driving a bunch at a frequency that corresponds to the maximum of the synchrotron frequency.

Sen, Tanaji; /Fermilab; Bhat, Chandra; /Fermilab; Kim, Hyung Jin; /Fermilab; Ostiguy, Jean-Francois; /Fermilab

2010-05-01T23:59:59.000Z

265

A new rf structure for intermediate-velocity particles  

Science Conference Proceedings (OSTI)

This paper describes an rf structure with high shunt impedance and good field stability for particle velocities o.1 {le} {beta} {le} 0.5. Traditionally, the drift-tube linac (DTL) has been the structure of choice for this velocity range. The new structure, called a coupled-cavity drift-tube linac (CCDTL), combines features of the Alvarez DTL and the {pi}-mode coupled-cavity linac (CCL). Each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between gaps is {gamma}{lambda}. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180{degrees}. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. We will discuss 2-D and 3-D electromagnetic code calculations, and some initial measurements on a low-power model of a CCDTL. We will compare shunt impedance calculations for DTL, CCL, and CCDTL structures. The CCDTL has potential application for a wide range of ion linacs. For example, high-intensity proton linacs could use the CCDTL instead of a DTL up to an energy of about 200 MeV. Another example is a stand-alone, low-duty, low-current, very high gradient, proton, cancer therapy machine. The advantage for this application would be a saving in the cost of the machine because the linac would be short.

Billen, J.H.; Krawczyk, F.L.; Wood, R.L.; Young, L.M.

1994-09-01T23:59:59.000Z

266

RF heating and current drive on NSTX with high  

SciTech Connect

NSTX is a small aspect ratio tokamak (R = 0.85 m, a = 0.65 m). The High Harmonic Fast Wave (HHFW) system is a 30 MHz, 12-element array capable of launching both symmetric and directional wave spectra for plasma heating and non-inductive current drive. It has delivered up to 6 MW for short pulses and has routinely operated at ~3 MW for 100-400 ms pulses. Results include strong, centrally-peaked electron heating in both D and He plasmas for both high and low phase velocity spectra. H-modes were obtained with application of HHFW power alone, with stored energy doubling after the L-H transition. Beta poloidal as large as unity has been obtained with significant fractions (0.4) of bootstrap current. Differences in the loop voltage are observed depending on whether the array is phased to drive current in the co- or counter-current directions. A fast ion tail with energies extending up to 140 keV has been observed when HHFW interacts with 80 keV neutral beams; neutron rate and lost ion measurements, as well as modeling, indicate significant power absorption by the fast ions. Radial rf power deposition and driven current profiles have been calculated with ray tracing and kinetic full-wave codes and compared with measurements.

Ryan, Philip Michael [ORNL; Peng, Yueng Kay Martin [ORNL

2003-01-01T23:59:59.000Z

267

Test results of the AGS Booster low frequency RF system  

Science Conference Proceedings (OSTI)

The Band II RF system was originally built to support the Booster operations during the acceleration of heavy ions. Designed to sweep from 0.6 to 2.5 MHz, it was build and successfully tested over a much broader range reaching 4 MHz. Voltages up to more than 20 kV were reached over the design frequency range. The system consists of two stations, each of which is made of one single gap cavity directly driven by a grounded cathode push pull power amplifier. The low Q high permeability ferrites needed in the coaxial cavity in order to reach the lower end of the band make tuning extremely easy. Both systems were thoroughly tested both at single frequencies and on a sweep and are now installed in the ring, ready for operations. Static measurements showed no high-loss effects. The Band 11 system has been fully described in a previous paper; presented here are the results of the ``bench`` tests that lead to important performance improvements.

Sanders, R.T.; Cameron, P.; Damm, R.; Dunbar, A.; Goldman, M.; Kasha, D.; McNerney, A.; Meth, M.; Ratti, A.; Spitz, R.

1993-06-01T23:59:59.000Z

268

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

269

Superconducting laser photocathode RF gun at BNL | U.S. DOE Office of  

Office of Science (SC) Website

Superconducting laser photocathode RF Superconducting laser photocathode RF gun at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives Superconducting laser photocathode RF gun at BNL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Superconducting laser photocathode RF gun Developed at: Brookhaven National Laboratory (BNL), New York and Advanced Energy Systems,

270

Experimental evaluation of 350 MHz RF accelerator windows for the low energy demonstration accelerator  

SciTech Connect

Radio frequency (RF) windows are historically a point where failure occurs in input power couplers for accelerators. To obtain a reliable, high-power, 350 MHz RF window for the Low Energy Demonstration Accelerator (LEDA) project of the Accelerator Production of Tritium program, RF windows prototypes from different vendors were tested. Experiments were performed to evaluate the RF windows by the vendors to select a window for the LEDA project. The Communications and Power, Inc. (CPI) windows were conditioned to 445 kW in roughly 15 hours. At 445 kW a window failed, and the cause of the failure will be presented. The English Electronic Valve, Inc. (EEV) windows were conditioned to 944 kW in 26 hours and then tested at 944 kW for 4 hours with no indication of problems.

Cummings, K.; Rees, D.; Roybal, W. [and others

1997-09-01T23:59:59.000Z

271

C-Band High Power RF Generation and Extraction Using a Dielectric...  

NLE Websites -- All DOE Office Websites (Extended Search)

C-BAND HIGH POWER RF GENERATION AND EXTRACTION USING A DIELECTRIC LOADED WAVEGUIDE* F. Gao , M. Conde, W. Gai, R. Konecny, W. Liu, J. Power, Z. Yusof ANL, Argonne, IL 60439,...

272

Delta-Sigma digital-RF modulation for high data rate transmitters  

E-Print Network (OSTI)

A low power, wideband wireless transmitter utilizing [Delta]-[Sigma] direct digital modulation of an RF carrier is presented. The transmitter architecture replaces high dynamic range analog circuits with high speed digital ...

Jerng, Albert

2007-01-01T23:59:59.000Z

273

Closed-cell 201.25 MHz RF structures for a muon cooling channel  

DOE Green Energy (OSTI)

We report on the research and development of high gradient low frequency closed-cell structures for possible use in a muon cooling channel. The presence of strong magnetic fields precludes the use of superconducting RF. These multi-cell structures have the ''beam iris'' closed by conducting oils, grids of tubes or other isolating structures. This greatly increases the shunt impedance and also allows the individually powered cells to be set independently to any phase. The isolating structure must be made using a very small amount of low-Z material to avoid unacceptable scattering of the muon beam. Various cell designs and methods of closure are presented and compared. The problems of RF heating and breakdown at high gradient are discussed with regard to the vulnerable isolating structures. RF, thermal and stress analyses are presented and the integration of the RF with the solenoid cryostat and liquid hydrogen absorbers is considered.

Rimmer, R.; Hartman, N.; Ladran, A.; Li, D.; Moretti, A.; Jurgens, T.

2001-06-01T23:59:59.000Z

274

Molecular-beam, laser-rf, double-resonance studies of calcium monohalide radicals  

SciTech Connect

The molecular-beam, laser-rf, double-resonance technique has been described a number of times. In essence, the occurrence of a radiofrequency (rf) transition in the electronic ground state of the molecule under study is detected by an increase in the laser-induced fluorescence of the molecular beam when the rf is on resonance. The technique makes it possible to measure small energy splittings (normally spin-rotational or hyperfine) in the electronic ground state of a molecule to an absolute precision of 1 kHz. The sensitivity of the technique is high because even a very small increase in fluorescence can be easily seen if the rf is swept repeatedly and digital data-handling techniques are used. The technique is useful for ionic as well as for neutral atoms and molecules.

Childs, W.J.; Cok, D.R.; Goodman, L.S.

1981-01-01T23:59:59.000Z

275

RF Cavity R&D at LBNL for the NLC Damping Rings, FY 1999  

NLE Websites -- All DOE Office Websites (Extended Search)

3 031299 RF Cavity R&D at LBNL for the NLC Damping Rings, FY1999 December 3, 1999 R. Rimmer, J.N. Corlett, G. Koehler, D. Li, N. Hartmann, J. Rasson, T.Saleh Lawrence Berkeley...

276

Wafer-scale 3D integration of silicon-on-insulator RF amplifiers  

E-Print Network (OSTI)

RF amplifiers are demonstrated using a three- dimensional (3D) wafer-scale integration technology based on silicon-on-insulator (SOI) CMOS process. This new 3D implementation reduces the amplifier size and shortens ...

Keast, Craig L.

277

Report on High Power rf Testing of Quartz Based DLA Structure  

NLE Websites -- All DOE Office Websites (Extended Search)

2 March, 2006 Report on High Power rf Testing of Quartz Based DLA Structure at NRL C. Jing, and R. Konecny Abstract: In this article, we report the experimental results of high...

278

RF Power Detector/Monitor Upgrade for the 500MHz Systems at the ALS  

E-Print Network (OSTI)

THE 500MHZ SYSTEMS AT THE ALS* K. Baptiste, LBNL, Berkeley,In the Advanced Light Source (ALS) Booster Ring and Storagedetectors in service in the ALS Storage Ring RF System only

Baptiste, K.

2003-01-01T23:59:59.000Z

279

Optimal RF Conditioning of Advanced Photon Source (APS) Fundamental Power Coupler  

E-Print Network (OSTI)

Experience at many laboratories regarding conditioning of RF Fundamental Power Couplers (FPC) has shown that it is a very apprehensive and laborious process. While the principle should remain unchanged, which is to gradually increase the rf power applied to the coupler while monitoring the vacuum level, the methodology is sometime different. With coupler lifetime being finite, some RF conditioning methods may be more conservative than others. The basic principle of coupler conditioning is to avoid the phenomena of metallisation, violent electrical discharges or other possible destructive phenomena. This document summarizes an optimized method which has demonstrated its effectiveness and for which the fundamental principles are: • Regulate RF power as a function of vacuum pressure around the coupler as fast as possible. • Apply a longer repetition period than the vacuum reading delay. • Follow the bare principle: low energy for low risk, by delivering pulses to the not yet conditioned coupler, initially...

Montesinos, E

2013-01-01T23:59:59.000Z

280

Brief evaluation of the control and rf systems in the Clinton P. Anderson Meson Physics Facility  

SciTech Connect

- From seminar on high-energy accelerator science; Tokyo and Tsukuba, Japan (5 Nov 1973). The design and operating experience with the computer control system and the rf power systems for the LAMPF linac are outlined. (WHK)

Hagerman, D.C.

1973-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Simulation of the Thorney Island Dense Gas Trial No. 8, using the code ADREA-HF  

SciTech Connect

In the framework of the evaluation of the three-dimensional, finite volume code ADREA-HF, a computational simulation of the Thorney Island Dense Gas Trial No. 8 is performed. A one-equation turbulence closure scheme is adopted in this first approach. The results of the simulation are compared with the experimental data in the form of concentration-time histories. The model predictions are satisfactory, with a tendency of the model to underestimate the maximum gas concentration and the time of its occurrence. The differences between model predictions and experimental data can be reduced by taking into account concentration fluctuations, utilization of finer numerical grids and improvements of the turbulence modeling. 3 refs., 14 figs.

Andronopoulos, S.; Wuertz, J. (Safety Technology Institute, Ispra (Italy)); Bartzis, J.G. (Institute for Nuclear Technology and Radiation Protection, Attiki (Greece)); Asimakopoulos, D. (Univ. of Athens (Greece))

1993-01-01T23:59:59.000Z

282

Quality Control of Surface Wave Data Estimated from Low Signal-to-Noise Ratio HF Radar Doppler Spectra  

Science Conference Proceedings (OSTI)

Ocean wave spectra estimated by high-frequency (HF) radar are very sensitive to the noise of Doppler spectra. The method for estimating wave spectra has been improved. This method is a nonlinear inversion and can be applied to a single radar case ...

Yukiharu Hisaki

2009-11-01T23:59:59.000Z

283

HF Radar Performance in a Low-Energy Environment: CODAR SeaSonde Experience on the West Florida Shelf  

Science Conference Proceedings (OSTI)

Three long-range (5 MHz) Coastal Ocean Dynamics Application Radar (CODAR) SeaSonde HF radars overlooking an array of as many as eight moored acoustic Doppler current profilers (ADCPs) have operated on the West Florida Shelf since September 2003 ...

Yonggang Liu; Robert H. Weisberg; Clifford R. Merz; Sage Lichtenwalner; Gary J. Kirkpatrick

2010-10-01T23:59:59.000Z

284

High-power testing of PEP-II RF cavity windows  

SciTech Connect

We describe the high power testing of RF cavity windows for the PEP-II B factory. The window is designed for continuous operation at 476 MHz with up to 500 kW throughput and has been tested to full power using a modified PEP Klystron. The windows use an anti-multipactor coating on the vacuum side and the application and processing of this layer is discussed. The high power test configuration, RF processing history and high power performance are described.

Neubauer, M.; Allen, M.; Fant, K.; Hill, A.; Hoyt, M.; Judkins, J.; Schwarz, H. [Stanford Linear Accelerator Center, CA (United States); Rimmer, R.A. [Lawrence Berkeley National Lab., CA (United States)

1996-06-01T23:59:59.000Z

285

Some issues on the RF system in the 3 GeV Fermilab pre-booster  

SciTech Connect

Some issues are presented on the rf system in the future Fermilab prebooster, which accelerates 4 bunches each containing 0.25 x 10{sub 14} protons from 1 to 3 GeV kinetic energy. The problem of beam loading is discussed. The proposal of having a non-tunable fixed-frequency rf system is investigated. Robinson's criteria for phase stability are checked and possible Robinson instability growth is computed.

Ng, K. Y.

1998-06-01T23:59:59.000Z

286

The upgraded rf system for the AGS and high intensity proton beams  

SciTech Connect

The AGS has been upgraded over the past three years to produce a record beam intensity of 6 {times} 10{sup 13} protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system`s performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading.

Brennan, J.M. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.

1995-05-01T23:59:59.000Z

287

The upgrade project for the RF system for the Brookhaven AGS  

SciTech Connect

The AGS operates a varied program of proton, heavy ion, and polarized proton acceleration for fixed-target experiments and will soon serve as the injector of these beams into the Relativistic Heavy Ion Collider, RHIC. The new Booster synchrotron extends the range of intensities and masses that can be accelerated. The 1.5 GeV injection energy increases the space charge limit by a factor of four to more than 6 {times} 10{sup 13} protons per pulse. To accommodate the increased beam current the rf system will be upgraded to provide more power and lower impedance to the beam. The flexibility of the rf system will also be enhanced by virtue of a new rf beam control system and installation of individual tuning servos for the ten rf cavities. The fundamental necessity for upgrading the rf system is to deliver more power to the accelerating beam. Three key ingredients of the upgrade project addressing this problem is (1) new power amplifiers provide the necessary power, and are closely coupled to the cavities, (2) wideband rf feedback reduces the effective impedance by a factor of 10, and (3) the capacitors loading the acceleration gaps (four per cavity) are increased from 275 pF to 600 pF.

Brennan, J.M.; Ciardullo, D.J.; Hayes, T.; Meth, M.; McNerney, A.J.; Otis, A.; Pirkl, W.; Sanders, R.; Spitz, R.; Toldo, F.; Zaltsman, A.

1993-06-01T23:59:59.000Z

288

Texture and pyramidal slip in Ti, Zr and their alloys  

Science Conference Proceedings (OSTI)

Zirconium, titanium and their alloys have a high anisotropic plastic behavior. One way to show this behavior is to analyze the evolution of the Lankford coefficient (R ([alpha]), values of which are obtained from tensile tests along different directions in the sheet plane). The variation of R([alpha]) can be explained from the crystallographic texture and the active deformation mechanisms. Microstructural observations show that prismatic slip is the most active deformation mode in these materials, but no dimensional change in the [lt][bar c][gt] direction of grains is possible by the activation of the (10[bar 1]0) [lt] 1[bar 2]10[gt] slip alone; so deformation along [0001] has to be accommodated either by (10[bar 1]o) [lt]1[bar 2]13[gt] (or [lt][bar c] + [bar a][gt]) pyramidal slip or by twinning. Many transmission electron microscopy (TEM) studies have shown evidence for [lt][bar c] + [bar a][gt] slip activity, and some authors have reported slip on (1[bar 1]01) planes in Ti alloys. The purpose of this paper is to contribute with another analysis of pyramidal slip activity in hcp textured materials, such as Ti and Zr alloys, and of the hardening mechanisms for this deformation mode. This analysis is performed both in a direct way, by means of TEM observations of deformed samples, and in an indirect way, by different mechanical tests.

Pochettino, A.A.; Gannio, N. (Dept. Ciencias de Materiales, Gcia. Desarroilo, CNEA, Avda. Libertador 8250, 1429 Buenos Aires (Argentina)); Edwards, C.V. (Esc Ing. Mecanica, Pont. Univ. Catolica, Av. Vicuna Mackenna, Santiago de Chile (Chile)); Penelle, R. (Lab. de Metallurgie Structurale, URA CNRS 1107, Bat 413, Univ. Paris XI, 91 405 Orsay (France))

1992-12-15T23:59:59.000Z

289

RF Design and Operating Results for a New 201.25 MHz RF Power Amplifier for LANSCE  

SciTech Connect

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.

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

290

Swift heavy ion irradiation-induced microstructure modification on two delta-phase oxides: Sc4Zr3O12 and Lu4Zr3O12  

Science Conference Proceedings (OSTI)

Swift gold ions (185 MeV) were used to systematically investigate the radiation damage response of delta phase compounds Sc{sub 4}Zr{sub 3}O{sub 12} and Lu{sub 4}Zr{sub 3}O{sub 12} in the electronic energy loss regime. Ion irradiation-induced microstructural modifications were examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD investigations indicate a phase transformation from ordered rhombohedral to disordered fluorite (O-D) in both compounds, with the Sc compound transforming at a higher ion fluence compared with the Lu compound. This result is consistent with our previous study on Sc{sub 4}Zr{sub 3}O{sub 12} and Lu{sub 4}Zr{sub 3}O{sub 12} under displacive radiation environment in which the nuclear energy loss is dominant. High resolution TEM revealed that individual ion tracks maintains crystalline structure where the core region experiences an O-D phase transformation. TEM observation also suggests that the O-D phase transformation occurs through the ion range after overlapping of ion tracks.

Tang, Ming [Los Alamos National Laboratory; Zhang, Jian [Los Alamos National Laboratory; Uberuaga, Blas P [Los Alamos National Laboratory; Sickafus, Kurt E [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Kluth, Patrick [AUSTRALIA; Maulik, Patel [INDIA

2009-01-01T23:59:59.000Z

291

Morphology evolution of ZrB{sub 2} nanoparticles synthesized by sol-gel method  

SciTech Connect

Zirconium diboride (ZrB{sub 2}) nanoparticles were synthesized by sol-gel method using zirconium n-propoxide (Zr(OPr){sub 4}), boric acid (H{sub 3}BO{sub 3}), sucrose (C{sub 12}H{sub 22}O{sub 11}), and acetic acid (AcOH). Clearly, it was a non-aqueous solution system at the very beginning of the reactions. Here, AcOH was used as both chemical modifier and solvent to control Zr(OPr){sub 4} hydrolysis. Actually, AcOH could dominate the hydrolysis by self-produced water of the chemical propulsion, rather than the help of outer water. C{sub 12}H{sub 22}O{sub 11} was selected, since it can be completely decomposed to carbon. Thus, carbon might be accounted precisely for the carbothermal reduction reaction. Furthermore, we investigated the influence of the gelation temperature on the morphology of ZrB{sub 2} particles. Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. An in-depth HRTEM observation revealed that the nanoparticles of ZrB{sub 2} were gradually fused together to evolve into a particle chain, finally into a rod-like shape. These crystalline nature of ZrB{sub 2} related to the gelation temperature obeyed the 'oriented attachment mechanism' of crystallography. - Graphical Abstract: Increasing the gelation temperature, the particle shapes changed from sphere-like particles at 65 deg. C to a particle chain at 75 deg. C, and then form rod-like particles at 85 deg. C. Highlights: > ZrB{sub 2} nanoparticles were synthesized by sol-gel method in an non-aqueous solution system. > AcOH was used as both chemical modifier and solvent to control Zr(OPr){sub 4} hydrolysis. > C{sub 12}H{sub 22}O{sub 11} was selected since it can be completely decomposed to carbon. > Increasing the gelation temperature, the particles changed from sphere-like to rod-like ones. > Crystalline nature of ZrB{sub 2} obeyed the 'oriented attachment mechanism' of crystallography.

Zhang Yun [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li Ruixing, E-mail: ruixingli@yahoo.com [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Jiang Yanshan; Zhao Bin; Duan Huiping [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li Junping; Feng Zhihai [Aerospace Research Institute of Materials and Processing Technology, Beijing 100076 (China)

2011-08-15T23:59:59.000Z

292

Self-interstitial configurations in hcp Zr: a first principles analysis  

Science Conference Proceedings (OSTI)

Analysis of microstructure evolution in irradiated Zr and Zr alloys based on the modern radiation damage theory suggests some important features of self-interstitial atoms (SIAs). Alignment of vacancy loops and voids along basal planes requires anisotropic interstitial transport with a dominant contribution along the basal plane. Under neutron irradiation this can be explained by one-dimensional mobility of SIA clusters but experiments under electron irradiation indicate unambiguously that even the single SIA should exhibit anisotropic diffusion. No experimental information is available on SIA properties in Zr and the data obtained by ab initio calculations within the last decade reported stable SIA configurations that should provide essentially three-dimensional diffusion. To clarify this issue, an extensive investigation of SIAs in Zr has been performed from first principles using two different codes. It was demonstrated that simulation cell size, type of pseudopotential, the exchange-correlation functional, and the c/a ratio are crucially important for determining the properties of interstitials in hcp Zr. The most stable SIA configurations lie in the basal plane, which should lead to SIA diffusion mainly along basal planes. The results provide a confirmation of basic mechanisms for microstructural evolution under irradiation.

Samolyuk, German D [ORNL; Golubov, Stanislav I [ORNL; Osetskiy, Yury N [ORNL; Stoller, Roger E [ORNL

2013-01-01T23:59:59.000Z

293

The Status of Normal Conducting RF (NCRF) Guns, a Summary of the ERL2005 Workshop  

Science Conference Proceedings (OSTI)

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DF in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.

Dowell, D.H.; /SLAC; Lewellen, J.W.; /Argonne; Nguyen, D.; /Los Alamos; Rimmer, R.; /Jefferson Lab

2006-03-13T23:59:59.000Z

294

The status of normal conducting RF (NCRF) guns; a summary of the ERL2005 Workshop  

SciTech Connect

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DF in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.

D.H. Dowell; J.W. Lewellen; D. Nguyen; R.A. Rimmer

2005-03-19T23:59:59.000Z

295

DESIGN CONSIDERATIONS FOR LOW FIELD SHORT PHOTO-INJECTED RF ELECTRON GUN WITH HIGH CHARGE ELECTRON BUNCH.  

Science Conference Proceedings (OSTI)

The RF field and space charge effect in a low field RF gun is given. The cell lengths are modified to have maximum accelerating efficiency. The modification introduces an extra RF field slice emittance. The phase space evolution of the following emittance compensation system is presented taking into account the chromatic effect. The emittance compensation mechanics for RF field and chromatic effect induced emittance is similar to that of compensating the space charge induced emittance. But the requirements are different to have best compensation for them. The beam waist is far in front of linac entrance to have best compensation for the RF field and chromatic effect induced emittance. For low field RF gun with high charge electron bunch this compensation is more important.

CHANG,X.; BEN-ZVI,I.; KEWISCH,J.

2004-06-21T23:59:59.000Z

296

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks  

Science Conference Proceedings (OSTI)

In this paper the per-node throughput and end-to-end delay of randomly deployed (i.e. ad-hoc) hybrid radio frequency - free space optics (RF/FSO) networks are studied. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, f(n) ... Keywords: Ad hoc networks, Delay, Free space optics, Hybrid networks, Throughput capacity

Di Wang; Alhussein A. Abouzeid

2011-05-01T23:59:59.000Z

297

An Efficient Supply Modulator for Linear Wideband RF Power Amplifiers  

E-Print Network (OSTI)

Radio Frequency (RF) Power Amplifiers are responsible for a considerable amount of the power consumption in the entire transmitter-receiver (transceiver) of modern communication systems. The stringent linearity requirements of multi-standard transceivers to minimize cross-talking effects makes Linear Power Amplifiers, particularly class A, the preferred choice in broadband transceivers. This linearity requirement coupled with the fact that the Power Amplifier operates at low transmit power during most of its operation makes the efficiency of the entire transceiver poor. The limited transceiver efficiency leads to a reduction in the battery life of battery operated portable devices like mobile phones; hence drastically limiting talk time. To alleviate this issue, several research groups propose solutions to improve PA power efficiency. However, these solutions usually have a low efficiency at low power and are mostly limited to narrow bandwidth applications. In this thesis, the efficiency of a class A Power amplifier in wideband wireless standards like WiMax is improved by dynamically controlling the bias current and supply voltage of the PA. An efficient supply modulator based on a switching regulator architecture is proposed for controlling the supply voltage. The switching regulator is found to be slew-limited by the bulky inductor and capacitor used to regulate the supply voltage. The proposed solution alleviates the slew rate limitation by adding a bang-bang controlled current source. The proposed supply modulator has an average power efficiency of 81.6 percent and is suitable for wireless standards with bandwidths up to 20MHz compared to the relatively lower efficiencies and bandwidths of state of the art modulators. A class-A PA is shown to promise an average power efficiency of 21.3 percent when the bias current is controlled dynamically and the supply voltage is varied using the proposed supply modulator. This is a significant improvement over the poor average efficiency of 1.06 percent for a fixed bias conventional linear class A PA. The project has been simulated using the TSMC 0.18 micrometer technology.

Turkson, Richard

2011-08-01T23:59:59.000Z

298

rf improvements for Spallation Neutron Source H{sup -} ion source  

SciTech Connect

The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering {approx}38 mA H{sup -} beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

Kang, Y. W.; Fuja, R.; Hardek, T.; Lee, S.-W.; McCarthy, M. P.; Piller, M. C.; Shin, K.; Stockli, M. P.; Welton, R. F. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Goulding, R. H. [Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2010-02-15T23:59:59.000Z

299

Simulation of RF Cavity Dark Current In Presence of Helical Magnetic Field  

Science Conference Proceedings (OSTI)

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.

Romanov, Gennady; Kashikhin, Vladimir; /Fermilab

2012-05-01T23:59:59.000Z

300

A SUMMARY OF TEST OBSERVATIONS WHEN IBUTTONS ARE SUBJECTED TO RF ENERGY  

SciTech Connect

The iButton is a 'one-wire', temperature sensor and data logger in a short metal cylinder package 17 mm in diameter and 6 mm tall. The device is designed to be attached to a surface and acquire temperature samples over time periods as short as 1 second to as long as 300 minutes. Both 8-bit and 16-bit samples are available with 8kB of memory available. Lifetime is limited to an internal battery that cannot be replaced or recharged. The RF test interest originated with the concern that the data logger could inadvertently record electrical emanations from other nearby equipment. The normal operation of the data logger does not support high speed sampling but the control interface will operate at either 15.4 kbps or 125 kbps. There were no observable effects in the operation of the module or in the data that could be attributed to the use of RF energy. They made the assumption that these devices would potentially show RF sensitivity in any of the registers and in the data memory equally, therefore gross changes in the data might show RF susceptibility. No such sensitivity was observed. Because significant power levels were used for these tests they can extrapolate downward in power to state that no RF susceptibility would occur at lower power levels given the same configurations.

Kane, R J; Baluyot, E V

2011-10-26T23:59:59.000Z

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301

The crystal structure of Hf{sub 1.5+{delta}}Nb{sub 1.5-{delta}}As and structure-composition relations in the section Hf{sub 3}As-Nb{sub 3}As  

Science Conference Proceedings (OSTI)

The title compound Hf{sub 1.5+{delta}}Nb{sub 1.5-{delta}}As was characterized by means of single crystal X-ray diffraction. It represents a new structure type of intermetallic compounds (space group Pnma; lattice parameters a=7.142(2) A, b=3.583(2) A, c=11.640(2) A) and shows a small homogeneity range corresponding to (0.1thermodynamic calculations employing the compound energy formalism (CEF) with the aim to model the experimentally observed site fraction data for both ternary compounds as well as Gibbs energies at the temperature of equilibration (1400 deg. C). - Graphical abstract: Hf{sub 1.5+{delta}}Nb{sub 1.5-{delta}}As with a new structure type (space group Pnma; lattice parameters a=7.142(2) A, b=3.583(2) A, c=11.640(2)A) was synthesized. Phase relations, energies and partial ordering in the section Hf{sub 3}As-Nb{sub 3}As were studied by first principle DFT calculations and thermodynamic modelling.

Warczok, Piotr; Chumak, Igor [Department of Inorganic Chemistry/Materials Chemistry, University of Vienna, Waehringerstr. 42, A-1090 Wien (Austria); Richter, Klaus W., E-mail: klaus.richter@univie.ac.a [Department of Inorganic Chemistry/Materials Chemistry, University of Vienna, Waehringerstr. 42, A-1090 Wien (Austria)

2009-04-15T23:59:59.000Z

302

Report of the ICFA Beam Dynamics Workshop 'Accelerators for a Higgs Factory: Linear vs. Circular' (HF2012)  

E-Print Network (OSTI)

This paper is a summary report of the ICFA Beam Dynamics Workshop 'Accelerators for a Higgs Factory: Linear vs. Circular' (HF2012). It discusses four types of accelerators as possible candidates for a Higgs factory: linear e+e- colliders, circular e+e- colliders, muon collider and photon colliders. The comparison includes: physics reach, performance (energy and luminosity), upgrade potential, technology maturity and readiness, and technical challenges requiring further R&D.

Alain Blondel; Alex Chao; Weiren Chou; Jie Gao; Daniel Schulte; Kaoru Yokoya

2013-02-14T23:59:59.000Z

303

Insights into the mechanisms on chemical reactions: reaction paths for chemical reactions. [Li + HF; OH + H/sub 2/  

DOE Green Energy (OSTI)

We report reaction paths for two prototypical chemical reactions: Li + HF, an electron transfer reaction, and OH + H/sub 2/, an abstraction reaction. In the first reaction we consider the connection between the energetic terms in the reaction path Hamiltonian and the electronic changes which occur upon reaction. In the second reaction we consider the treatment of vibrational effects in chemical reactions in the reaction path formalism. 30 refs., 9 figs.

Dunning, T.H. Jr.; Rosen, E.; Eades, R.A.

1987-01-01T23:59:59.000Z

304

Skill Assessment of Resolving Ocean Surface Current Structure Using Compact-Antenna-Style HF Radar and the MUSIC Direction-Finding Algorithm  

Science Conference Proceedings (OSTI)

A skill analysis of the Multiple Signal Characterization (MUSIC) algorithm used in compact-antenna-style HF radar ocean current radial velocity/bearing determination is performed using simulation. The simulation is based upon three collocated ...

Tony de Paolo; Eric Terrill

2007-07-01T23:59:59.000Z

305

Simulations of RF capture with barrier bucket in booster at injection  

Science Conference Proceedings (OSTI)

As part of the effort to increase the number of ions per bunch in RHIC, a new scheme for RF capture of EBIS ions in Booster at injection has been developed. The scheme was proposed by M. Blaskiewicz and J.M. Brennan. It employs a barrier bucket to hold a half turn of beam in place during capture into two adjacent harmonic 4 buckets. After acceleration, this allows for 8 transfers of 2 bunches from Booster into 16 buckets on the AGS injection porch. During the Fall of 2011 the necessary hardware was developed and implemented by the RF and Controls groups. The scheme is presently being commissioned by K.L. Zeno with Au32+ ions from EBIS. In this note we carry out simulations of the RF capture. These are meant to serve as benchmarks for what can be achieved in practice. They also allow for an estimate of the longitudinal emittance of the bunches on the AGS injection porch.

Gardner, C.J.

2012-01-23T23:59:59.000Z

306

RF transmission line and drill/pipe string switching technology for down-hole telemetry  

DOE Patents (OSTI)

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.

Clark, David D. (Santa Fe, NM); Coates, Don M. (Santa Fe, NM)

2007-08-14T23:59:59.000Z

307

Parasitic Effects Reduction for Wafer-Level Packaging of RF-Mems  

E-Print Network (OSTI)

In RF-MEMS packaging, next to the protection of movable structures, optimization of package electrical performance plays a very important role. In this work, a wafer-level packaging process has been investigated and optimized in order to minimize electrical parasitic effects. The RF-MEMS package concept used is based on a wafer-level bonding of a capping silicon substrate to an RF-MEMS wafer. The capping silicon substrate resistivity, substrate thickness and the geometry of through-substrate electrical interconnect vias have been optimized using finite-element electromagnetic simulations (Ansoft HFSS). Test structures for electrical characterization have been designed and after their fabrication, measurement results will be compared with simulations.

Iannacci, J; Sinaga, S; Gaddi, R; Gnudi, A; Bartek, M

2007-01-01T23:59:59.000Z

308

Generation of ELF and VLF waves by HF-modulated polar electrojet via a thermal instability process  

SciTech Connect

Generation of ELF and VLF waves via a thermal instability process in a HF-modulated polar electrojet has been investigated. It is shown that a positive feedback through the electron-neutral collisional heating process can cause the transient response of the plasma to the modulated HF heater to grow exponentially. The threshold fields of the instability under normal electrojet conditions are found to be about 2.25 V/m and 1.13 V/m for the operation of the o-mode and x-mode heaters with a 50% duty cycle, respectively. For a heater wave field of, e.g., 1.5 V/m, the instability can be excited by the x-mode heater within a few tens of millisecond. The predicted dependence of the ELF/VLF radiation amplitude on the percentage of the duty cycle of the HF modulation is identical to that of the recent observational results of Barr and Stubbe. 28 refs., 2 figs.

Kuo, S.P. (Polytechnic Univ., Farmingdale, NY (United States)); Lee, M.C. (Massachusetts Inst. of Technology, Cambridge (United States))

1993-02-05T23:59:59.000Z

309

Accelerated Publication: Drain current enhancement and negligible current collapse in GaN MOSFETs with atomic-layer-deposited HfO2 as a gate dielectric  

Science Conference Proceedings (OSTI)

Accumulation-type GaN metal-oxide-semiconductor field-effect-transistors (MOSFET's) with atomic-layer-deposited HfO"2 gate dielectrics have been fabricated; a 4@mm gate-length device with a gate dielectric of 14.8nm in thickness (an equivalent SiO"2 ... Keywords: Atomic layer deposition (ALD), Current collapse, GaN, HfO2, Metal-oxide-semiconductor field-effect-transistor (MOSFET)

Y. C. Chang; W. H. Chang; Y. H. Chang; J. Kwo; Y. S. Lin; S. H. Hsu; J. M. Hong; C. C. Tsai; M. Hong

2010-11-01T23:59:59.000Z

310

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

Science Conference Proceedings (OSTI)

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)

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

311

Effect of RF Gradient upon the Performance of the Wisconsin SRF Electron Gun  

SciTech Connect

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.

Bosch, Robert [SRC U. Wisconsin-Madison; Legg, Robert A. [JLAB

2013-12-01T23:59:59.000Z

312

Mini RF-driven ion source for focused ion beam system  

DOE Green Energy (OSTI)

Mini RF-driven ion sources with 1.2 cm and 1.5 cm inner chamber diameter have been developed at Lawrence Berkeley National Laboratory. Several gas species have been tested including argon, krypton and hydrogen. These mini ion sources operate in inductively coupled mode and are capable of generating high current density ion beams at tens of watts. Since the plasma potential is relatively low in the plasma chamber, these mini ion sources can function reliably without any perceptible sputtering damage. The mini RF-driven ion sources will be combined with electrostatic focusing columns, and are capable of producing nano focused ion beams for micro machining and semiconductor fabrications.

Jiang, X.; Ji, Q.; Chang, A.; Leung, K.N.

2002-08-02T23:59:59.000Z

313

High power tests of dressed supconducting 1.3 GHz RF cavities  

SciTech Connect

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.

Hocker, A.; Harms, E.R.; Lunin, A.; Sukhanov, A.; /Fermilab

2011-03-01T23:59:59.000Z

314

Simulation and analysis of rf feedback systems on the SLC damping rings  

SciTech Connect

The rf system of the SLC Damping Rings has evolved since tighter tolerances on beam stability are encountered as beam intensities are increased. There are now many feedback systems controlling the phase and amplitude of the rf, the phase of the beam, and the tune of the cavity. The bandwidths of the feedback loops range from several MHz to compensate for beam loading to a few Hz for the cavity tuners. To improve our understanding of the interaction of these loops and verify the expected behavior, we have simulated their behavior using computer models. A description of the models and the first results are discussed.

Minty, M.; Himel, T.; Krejcik, P.; Siemann, R.H.; Tighe, R.

1993-09-01T23:59:59.000Z

315

Plasma sweeper to control the coupling of RF power to a magnetically confined plasma  

DOE Patents (OSTI)

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.

Motley, Robert W. (Princeton, NJ); Glanz, James (Lawrenceville, NJ)

1985-01-01T23:59:59.000Z

316

RF System Upgrades to the Advanced Photon Source Linear Accelerator in Support of the Fel Operation  

E-Print Network (OSTI)

The S-band linear accelerator, which was built to be the source of particles and the front end of the Advanced Photon Source injector, is now also being used to support a low-energy undulator test line (LEUTL) and to drive a free-electron laser (FEL). The more severe rf stability requirements of the FEL have resulted in an effort to identify sources of phase and amplitude instability and implement corresponding upgrades to the rf generation chain and the measurement system. Test data and improvements implemented and planned are described

Smith, T L; Grelick, A E; Pile, G; Nassiri, A; Arnold, N

2000-01-01T23:59:59.000Z

317

Coherent Spin Manipulations of a Polarized Beam With a Localized RF Magnetic Field  

E-Print Network (OSTI)

The coherent manipulation of spin observables in storage rings provides opportunities to test the application of some fundamental dynamical principles. In this context, it is possible to confirm, using gauge invariance and Lorentz invariance, a conjecture framed by A. M. Kondratenko concerning the "natural" or "intrinsic" resonance strength applicable to a spin rotation from a controlled Froissart-Stora sweep with an RF dipole magnet. The discussion includes a brief treatment of the "forced" component of the resonance strength associated with the effect of the betatron oscillations induced by the operation of the RF diple and a discussion of the effective resonance strength as a function of betatron tunes.

Dennis Sivers

2007-10-12T23:59:59.000Z

318

Effects of the oxygen precursor on the electrical and structural properties of HfO{sub 2} films grown by atomic layer deposition on Ge  

SciTech Connect

We report on the growth by atomic layer deposition of HfO{sub 2} films on HF-last treated Ge(001) substrates using HfCl{sub 4} as a Hf source and either O{sub 3} or H{sub 2}O as oxygen sources. The choice of the oxygen precursor strongly influences the structural, chemical, and electrical properties of the HfO{sub 2} films: Those grown using H{sub 2}O exhibit local epitaxial growth, a large amount of contaminants such as chlorine and carbon, and a large frequency dispersion of the capacitance-voltage (C-V) characteristics. Films grown using O{sub 3} are good insulators and exhibit well-shaped C-V curves with a minimum frequency dispersion of the accumulation capacitance. Moreover, they are smoother, less crystallized, and with a lower contaminant content than those grown using H{sub 2}O. However, the use of O{sub 3} leads to the formation of a 2 nm thick layer, possibly GeO{sub x}, at the HfO{sub 2}/Ge interface.

Spiga, S.; Wiemer, C.; Tallarida, G.; Scarel, G.; Ferrari, S.; Seguini, G.; Fanciulli, M. [Laboratorio Nazionale MDM-INFM, Via C. Olivetti 2, 20041 Agrate Brianza, MI (Italy)

2005-09-12T23:59:59.000Z

319

Low temperature rf sputtering deposition of (Ba, Sr) TiO{sub 3} thin film with crystallization enhancement by rf power supplied to the substrate  

SciTech Connect

The (Ba, Sr) TiO{sub 3} thin film deposited by radio frequency (rf) sputtering requires a high deposition temperature near 500 deg. C to realize a high relative dielectric constant over of 300. For example, the film deposited at 330 deg. C contains an amorphous phase and shows a low relative dielectric constant of less than 100. We found that rf power supplied not only to the (Ba, Sr) TiO{sub 3} sputtering target, but also to the substrate during the initial step of film deposition, enhanced the crystallization of the (Ba, Sr) TiO{sub 3} film drastically and realized a high dielectric constant of the film even at low deposition temperatures near 300 deg. C. The 50-nm-thick film with only a 10 nm initial layer deposited with the substrate rf biasing is crystallized completely and shows a high relative dielectric constant of 380 at the deposition temperature of 330 deg. C. The (Ba, Sr) TiO{sub 3} film deposited at higher temperatures (upwards of 400 deg. C) shows <110> preferred orientation, while the film deposited at 330 deg. C with the 10 nm initial layer shows a <111> preferred orientation on a <001>-oriented ruthenium electrode. The unit cell of (Ba, Sr) TiO{sub 3} (111) plane is similar to that of ruthenium (001) plane. We conclude that the rf power supplied to the substrate causes ion bombardments on the (Ba, Sr) TiO{sub 3} film surface, which assists the quasiepitaxial growth of (Ba, Sr) TiO{sub 3} film on the ruthenium electrode at low temperatures of less than 400 deg. C.

Yoshimaru, Masaki; Takehiro, Shinobu; Abe, Kazuhide; Onoda, Hiroshi [System LSI Research Division, Silicon Solution Company, Oki Electric Industry Co., Ltd., 550-1, Higashi-asakawa, Hachioji, Tokyo 193-8550 (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Strategic Planning Office, Silicon Manufacturing Company, Oki Electric Industry Co., Ltd., 550-1, Higashi-asakawa, Hachioji, Tokyo 193-8550 (Japan)

2005-05-01T23:59:59.000Z

320

Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites  

DOE Patents (OSTI)

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.

Norem, James H.; Pellin, Michael J.

2013-06-11T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Low temperature high density Si3N4 MIM capacitor technology for MMMIC and RF-MEMs applications  

Science Conference Proceedings (OSTI)

In this work, a novel, high quality, high-density, deposited at room temperature ultra thin 5 nm Si3N4 metal insulator metal (MIM) capacitor process for monolithic millimetre-wave integrated circuit (MMMIC) applications ... Keywords: RF MEMs, RF MIM capacitors, dielectric films, high density capacitors, room temperature ultra thin silicon nitride films metal insulator metal capacitors

K. Elgaid; H. Zhou; C. D. W. Wilkinson; I. G. Thayne

2004-06-01T23:59:59.000Z

322

Fourier Spectrum-Based Signature Test: A Genetic CAD Toolbox for Reliable RF Testing Using Low-Performance Test Resources  

Science Conference Proceedings (OSTI)

At the present time, coordinated EDA tools for RF/mixed-signal pin test do not exist. In this paper, a CAD tool for efficient production testing of highperformance RF systems using low-cost baseband ATE is presented. The CAD tool consists of a custom ...

G. Srinivasan; A. Chatterjee

2007-10-01T23:59:59.000Z

323

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 55, NO. 10, OCTOBER 2007 2043 Power Supply Rejection for RF Amplifiers  

E-Print Network (OSTI)

from noise or voltage ripple on the power supply. As demonstrated in Fig. 1, spectral energy injected the interaction of supply noise with RF amplifier components for successful design of the system. In the context noted, the op- erator is not fully symmetric in this representation because the supply noise and RF

Sanders, Seth

324

814 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 50, NO. 3, MARCH 2002 Power Amplifiers and Transmitters for RF  

E-Print Network (OSTI)

resistances. The 1990s saw a proliferation of a variety of new solid-state devices including HEMT, pHEMT, HFET, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active of generating and controlling RF signals, and vacuum-tube PAs were dominant from the late 1920s through the mid

Popovic, Zoya

325

IBM-1 calculations towards the neutron-rich nucleus $^{106}$Zr  

E-Print Network (OSTI)

The neutron-rich N=66 isotonic and A=106 isobaric chains, covering regions with varying types of collectivity, are interpreted in the framework of the interacting boson model. Level energies and electric quadrupole transition probabilities are compared with available experimental information. The calculations for the known nuclei in the two chains are extrapolated towards the neutron-rich nucleus $^{106}$Zr.

S. Lalkovski; P. Van Isacker

2009-03-23T23:59:59.000Z

326

IBM-1 calculations towards the neutron-rich nucleus $^{106}$Zr  

E-Print Network (OSTI)

The neutron-rich N=66 isotonic and A=106 isobaric chains, covering regions with varying types of collectivity, are interpreted in the framework of the interacting boson model. Level energies and electric quadrupole transition probabilities are compared with available experimental information. The calculations for the known nuclei in the two chains are extrapolated towards the neutron-rich nucleus $^{106}$Zr.

Lalkovski, S

2009-01-01T23:59:59.000Z

327

Effect of particle morphology on sinterability of SiC-ZrO2 in microwave  

Science Conference Proceedings (OSTI)

The effect of particle morphology on the sinterability of microwave-sintered SiC-ZrO2 was evaluated in this paper. A comparison was alsomade against the electric furnace and resulted in faster heating rate because of the difference of heat ...

Lydia Anggraini; Kei Ameyama

2012-01-01T23:59:59.000Z

328

A Z-R Relation for Summertime Convective Clouds over West Texas  

Science Conference Proceedings (OSTI)

A set of Z-R relations is derived by linear regression for summertime convective rainfall in West Texas from data gathered with an SWR-75 weather radar and a network of weighing bucket raingages. Data from 21 storms were grouped into storm were ...

Eric A. Pani; Gerald M. Jurica

1989-10-01T23:59:59.000Z

329

The integration of Human Factors (HF) in the SAR process training course text  

SciTech Connect

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.

Ryan, T.G.

1995-03-01T23:59:59.000Z

330

Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging  

DOE Patents (OSTI)

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.

Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

1984-01-01T23:59:59.000Z

331

Electrical and gas-sensitive properties of nanostructured SnO{sub 2}:ZrO{sub 2} semiconductor films  

Science Conference Proceedings (OSTI)

The results of a study of the effect of atomic composition of metal-oxide semiconductor composites SnO{sub 2}:ZrO{sub 2} on the surface morphology, polycrystal grain size, resistivity, concentration, free-carrier mobility, and gas-sensitive properties of thin films (0.5-2.5 {mu}m) are presented. Films SnO{sub 2} with ZrO{sub 2} additives (the Zr content was varied from 0.5 to 4.6 at %) are grown by reactive ion-beam sputtering of metal targets of different compositions in a controlled Ar + O{sub 2} atmosphere. Using transmission electron microscopy, atomic-force microscopy, and high-resolution transmission electron microscopy, it is experimentally shown that, as the Zr content increases in the SnO{sub 2}:ZrO{sub 2} film composition, the polycrystal grain size decreases from 45 to 10 nm, the free-carrier concentration decreases almost by four orders of magnitude and the mobility increases by approximately nine times. As the Zr content increases in the SnO{sub 2}:ZrO{sub 2} film from 0.5 to 4.6 at %, the temperature of maximum gas sensitivity of films to such gases as ethanol, isopropyl alcohol, and acetone decreases by 100-190 Degree-Sign C.

Rembeza, S. I., E-mail: rembeza@yandex.ru; Kosheleva, N. N.; Rembeza, E. S.; Svistova, T. V.; Shmatova, Yu. V. [Voronezh State Technical University (Russian Federation); Xu Gang [Tsinghua University (China)

2011-05-15T23:59:59.000Z

332

Low-frequency RF Coupling To Unconventional (Fat Unbalanced) Dipoles  

SciTech Connect

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

Ong, M M; Brown, C G; Perkins, M P; Speer, R D; Javedani, J B

2010-12-07T23:59:59.000Z

333

Conservation Biology (Biology 45300) An Ecology Course for the Fall of 2007 with RF Rockwell  

E-Print Network (OSTI)

Conservation Biology (Biology 45300) An Ecology Course for the Fall of 2007 with RF Rockwell Biology 45300 - Conservation Biology This undergraduate course provides an introduction to conservation biology with an emphasis on the interplay of various fields of biology in the mamangement and conservation

Lombardi, John R.

334

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

335

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

336

Optical Investigations of Dust Particles Distribution in RF and DC Discharges  

Science Conference Proceedings (OSTI)

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.

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

337

RF undulator for compact X-ray SASE source of variable wavelength  

Science Conference Proceedings (OSTI)

A room-temperature RF undulator, fed by Ka-band radiation and intended to produce {approx}1 nm wavelength radiation using moderate energy electrons, is considered. The necessary electron bunches with energy 0.2-1 GeV could be produced by petawatt laser pulses injected into plasma bubbles.

Kuzikov, S. V.; Hirshfield, J. L.; Jiang, Y.; Marshall, T. C.; Vikharev, A. A. [Institute of Applied Physics, 46 Ulyanov St., Nizhny Novgorod, 603950 (Russian Federation) and Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States) and Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States); Omega-P, Inc., New Haven, CT (United States) and Columbia University, New York, NY (United States); Yale University, New Haven, CT (United States)

2012-12-21T23:59:59.000Z

338

Development of fundamental power coupler for high-current superconducting RF cavity  

SciTech Connect

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.

Jain P.; Belomestnykh, S.; Ben-Zvi, I.; Xu, W.

2012-05-20T23:59:59.000Z

339

Influence of Intense Beam in High Pressure Hydrogen Gas Filled RF Cavities  

DOE Green Energy (OSTI)

The influence of an intense beam in a high-pressure gas filled RF cavity has been measured by using a 400 MeV proton beam in the Mucool Test Area at Fermilab. The ionization process generates dense plasma in the cavity and the resultant power loss to the plasma is determined by measuring the cavity voltage on a sampling oscilloscope. The energy loss has been observed with various peak RF field gradients (E), gas pressures (p), and beam intensities in nitrogen and hydrogen gases. Observed RF energy dissipation in single electron (dw) in N{sub 2} and H{sub 2} gases was 2 10{sup -17} and 3 10{sup -17} Joules/RF cycle at E/p = 8 V/cm/Torr, respectively. More detailed dw measurement have been done in H{sub 2} gas at three different gas pressures. There is a clear discrepancy between the observed dw and analytical one. The discrepancy may be due to the gas density effect that has already been observed in various experiments.

Yonehara, K.; Chung, M.; Collura, M.G.; Jana, M.R.; Leonova, M.; Moretti, A.; Popovic, M.; Schwarz, T.; Tollestrup, A.; /Fermilab; Johnson, R.P.; Franagan, G.; /Muons, Inc. /IIT

2012-05-01T23:59:59.000Z

340

The design of a high efficiency RF power amplifier for an MCM process  

E-Print Network (OSTI)

In this thesis, I addressed issues arising in the design of a high efficiency RF power amplifier for the Draper Laboratory multi-chip module (MCM) process. A design for a 2.3 GHz PCB amplifier using an enhancement-mode ...

Noonan, James (James Keating)

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

New high power 200 MHz RF system for the LANSCE drift tube linac  

SciTech Connect

The Los Alamos Neutron Science Center (LANSCE) linac provides an 800 MeV direct H{sup +} proton beam, and injects H{sup {minus}} to the upgraded proton storage ring for charge accumulation for the Short Pulse Spallation Source. Accelerating these interlaced beams requires high average power from the 201.25 MHz drift tube linac (DTL) RF system. Three power amplifiers have operated at up to three Megawatts with 12% duty factor. The total number of electron power tubes in the RF amplifiers and their modulators has been reduced from fifty-two to twenty-four. The plant continues to utilize the original design of a tetrode driving a super power triode. Further increases in the linac duty factor are limited, in part, by the maximum dissipation ratings of the triodes. A description of the system modifications proposed to overcome these limitations includes new power amplifiers using low-level RF modulation for tank field control. The first high power Diacrode{reg_sign} is being delivered and a new amplifier cavity is being designed. With only eight power tubes, the new system will deliver both peak power and high duty factor, with lower mains power and cooling requirements. The remaining components needed for the new RF system will be discussed.

Lyles, J.; Friedrichs, C.; Lynch, M.

1998-12-31T23:59:59.000Z

342

Laser cooling and sympathetic cooling in a linear quadrupole rf trap  

E-Print Network (OSTI)

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. The dependence of rf heating rates on the ion temperature, trapping parameters, and the number of ions is obtained. New rf heating mechanism affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and the influence of the rf heating rates on the fluorescence lineshapes is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.

Ryjkov, Vladimir Leonidovich

2003-12-01T23:59:59.000Z

343

Mitigating the effects of RF interference through RSSI-Based error recovery  

Science Conference Proceedings (OSTI)

On a common sensor node platform (Telos) we sample RSSI with high frequency during packet reception. We find that a packet collision (RF interference) often manifests as a measurable, temporal increase in RSSI. We investigate how the receiver ... Keywords: ARQ, interference mitigation, packet combining

Jan-Hinrich Hauer; Andreas Willig; Adam Wolisz

2010-02-01T23:59:59.000Z

344

Performance evaluation of indoor localization techniques based on RF power measurements from active or passive devices  

Science Conference Proceedings (OSTI)

The performance of networks for indoor localization based on RF power measurements from active or passive devices is evaluated in terms of the accuracy, complexity, and costs. In the active device case, the terminal to be located measures the power transmitted ...

Damiano De Luca; Franco Mazzenga; Cristiano Monti; Marco Vari

2006-01-01T23:59:59.000Z

345

RF Couplers for Normal-Conducting Photoinjector of High-Power CW FEL  

E-Print Network (OSTI)

A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. A preliminary design of a normal-conducting, 2.5-cell pi-mode, 700-MHz CW RF photoinjector that will be built for demonstration purposes, is completed. This photoinjector will be capable of accelerating a 100-mA electron beam (3 nC per bunch at 35 MHz bunch repetition rate) to 2.7 MeV while providing an emittance below 7 mm-mrad at the wiggler. More than 1 MW of RF power will be fed into the photoinjector cavity through two ridge-loaded tapered waveguides. The waveguides are coupled to the cavity by "dog-bone" irises cut in a thick wall. Due to CW operation of the photoinjector, the cooling of the coupler irises is a rather challenging thermal management project. This paper presents results of a detailed electromagnetic modeling of the coupler-cavity system, which has been performed to select the coupler design that minimizes the iris heating due to RF power loss in its walls.

Kurennoy, Sergey; Wood, Richard L; Schultheiss, T J; Rathke, John; Young, Lloyd

2004-01-01T23:59:59.000Z

346

RF Distribution System for High Power Test of the SNS Cryomodule  

Science Conference Proceedings (OSTI)

A four-way waveguide RF power distribution system for testing the Spallation Neutron Source (SNS) multi-cavity cryomodule to investigate the collective behavior has been developed. A single klystron operating at 805MHz for 1.3 msec at 60Hz powers the 4-way waveguide splitter to deliver up to 400 kW to individual cavities. Each cavity is fed through a combination of waveguide splitters and vector modulators (VM) to provide independent magnitude and phase controls. The waveguide vector modulator consists of two quadrature hybrids and two motorized waveguide phase shifters. The phase shifters and the assembled waveguide vector modulators were individually tested and characterized for low power and high RF power in the SNS RF test facility. Precise calibrations of magnitude and phase were performed to generate the look up tables (LUTs) to provide operational references during the cryomodule test. An I-Q demodulator module was developed and utilized to measure relative phases in pulsed high RF power operation. PLC units were developed for mechanical control of the phase shifters. Initial low/high power measurements were made using LabVIEW. An operation algorithm has been implemented into EPICS control for the cryomodule test stand.

Lee, Sung-Woo [ORNL; Kang, Yoon W [ORNL; Broyles, Michael R [ORNL; Crofford, Mark T [ORNL; Geng, Xiaosong [ORNL; Kim, Sang-Ho [ORNL; Phibbs, Curtis L [ORNL; Strong, William Herb [ORNL; Peglow, Robert C [ORNL; Vassioutchenko, Alexandre V [ORNL

2012-01-01T23:59:59.000Z

347

RF couplers for normal-conducting photoinjector of high-power CW FEL  

SciTech Connect

A high-current emittance-compensated RF photoinjector is a key enabling technology for a high-power CW FEL. A preliminary design of a normal-conducting, 2.5-cell pi-mode, 700-MHz CW RF photoinjector that will be built for demonstration purposes, is completed. This photoinjector will be capable of accelerating a 100-mA electron beam (3 nC per bunch at 35 MHz bunch repetition rate) to 2.7 MeV while providing an emittance below 7 mm-mrad at the wiggler. More than 1 MW of RF power will be fed into the photoinjector cavity through two ridge-loaded tapered waveguides. The waveguides are coupled to the cavity by 'dog-bone' irises cut in a thick wall. Due to CW operation of the photoinjector, the cooling of the coupler irises is a rather challenging thermal management project. This paper presents results of a detailed electromagnetic modeling of the coupler-cavity system, which has been performed to select the coupler design that minimizes the iris heating due to RF power loss in its walls.

Kurennoy, S. (Sergey)

2004-01-01T23:59:59.000Z

348

Low emittance electron beam production and characterization with a 17 GHz photocathode RF gun  

E-Print Network (OSTI)

This thesis presents theoretical and experimental results of the production of very high brightness electron beams using a 17 GHz photocathode RF gun. A beam brightness of up to 8x 1013 A/([pi]m rad)2 was measured for a 1 ...

Brown, Winthrop Joseph

2001-01-01T23:59:59.000Z

349

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

E-Print Network (OSTI)

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 is one of the most important technological challenges for the development of compact transceivers. In this work, novel miniaturization techniques were investigated for single-band, dual-band, ultra-wideband and tunable bandpass filters. In single-band filters, the use of cross-shaped fractals in half-mode substrate-integrated-waveguide bandpass filters resulted in a 37 percent size reduction. A compact bandpass filter that occupies an area of 0.315 mm2 is implemented in 90-nm CMOS technology for 20 GHz applications. For dual-band filters, using half-mode substrate-integrated-waveguides resulted in a filter that is six times smaller than its full-mode counterpart. For ultra-wideband filters, using slow-wave capacitively-loaded coplanar-waveguides resulted in a filter with improved stopband performance and frequency notch, while being 25 percent smaller in size. A major part of this work also dealt with the concept of 'hybrid' RF MEMS tunable filters where packaged, off-the-shelf RF MEMS switches were used to implement high-performance tunable filters using substrate-integrated-waveguide technology. These 'hybrid' filters are very easily fabricated compared to current state-of-the-art RF MEMS tunable filters because they do not require a clean-room facility. Both the full-mode and half-mode substrate-integrated waveguide tunable filters reported in this work have the best Q-factors (93 - 132 and 75 - 140, respectively) compared to any 'hybrid' RF MEMS tunable filter reported in current literature. Also, the half-mode substrate-integrated waveguide tunable filter is 2.5 times smaller than its full-mode counterpart while having similar performance. This dissertation also presented detailed analytical and simulation-based studies of nonlinear noise phenomena induced by Brownian motion in all-pole RF MEMS tunable filters. Two independent mathematical methods are proposed to calculate phase noise in RF MEMS tunable filters: (1) pole-perturbation approach, and (2) admittance-approach. These methods are compared to each other and to harmonic balance noise simulations using the CAD-model of the RF MEMS switch. To account for the switch nonlinearity in the mathematical methods, a nonlinear nodal analysis technique for tunable filters is also presented. In summary, it is shown that output signal-to-noise ratio degradation due to Brownian motion is maximum for low fractional bandwidth, high order and high quality factor RF MEMS tunable filters. Finally, a self-sustained microwave platform to detect the dielectric constant of organic liquids is presented in this dissertation. The main idea is to use a voltage- controlled negative-resistance oscillator whose frequency of oscillation varies according to the organic liquid under test. To make the system self-sustained, the oscillator is embedded in a frequency synthesizer system, which is then digitally interfaced to a computer for calculation of dielectric constant. Such a system has potential uses in a variety of applications in medicine, agriculture and pharmaceuticals.

Sekar, Vikram

2011-08-01T23:59:59.000Z

350

Theoretical Predictions and Experimental Assessments of the Performance of Alumina RF Windows  

SciTech Connect

Radio frequency (RF) windows are the most likely place for catastrophic failure to occur in input power couplers for particle accelerators. Reliable RF windows are essential for the success of the Accelerator Production of Tritium (APT) program because there are over 1000 windows on the accelerator, and it takes more than one day to recover from a window failure. The goals of this research are to analytically predict the lifetime of the windows, to develop a conditioning procedure, and to evaluate the performance of the RF windows. The analytical goal is to predict the lifetime of the windows. The probability of failure is predicted by the combination of a finite element model of the window, Weibull probabilistic analysis, and fracture mechanics. The window assembly is modeled in a finite element electromagnetic code in order to calculate the electric fields in the window. The geometry (i.e. mesh) and electric fields are input into a translator program to generate the mesh and boundary conditions for a finite element thermal structural code. The temperatures and stresses are determined in the thermal/structural code. The geometry and thermal structural results are input into another translator program to generate an input file for the reliability code. Material, geometry and service data are also input into the reliability code. To obtain accurate Weibull and fatigue data for the analytical model, four point bend tests were done. The analytical model is validated by comparing the measurements to the calculations. The lifetime of the windows is then determined using the reliability code. The analytical model shows the window has a good thermal mechanical design and that fast fracture is unlikely to occur below a power level of 9 Mw. The experimental goal is to develop a conditioning procedure and evaluate the performance of RF windows. During the experimental evaluation, much was learned about processing of the windows to improve the RF performance. Methods of processing included grit blasting and using various coatings.

Karen Ann Cummings

1998-07-01T23:59:59.000Z

351

Investigations of the g{sub K}-factors in the {sup 175,177,179}Hf Isotopes  

Science Conference Proceedings (OSTI)

In this paper the intrinsic g{sub K} and effective spin g{sub s} factors of the odd-mass {sup 175-179}Hf isotopes have been investigated within the Tamm-Dancoff approximation by using the realistic Saxon-Woods potential. The theoretically calculated g{sub K} and g{sub s}{sup eff} values are compared with experimental data. The comparison of the measured and calculated values of the effective g{sub s} factor shows that the spin polarization explains quite well the observed reduction of g{sub s} from its free-nucleon value.

Yakut, Hakan; Kuliev, Ali [Sakarya University, Department of physics, Sakarya (Turkey); Guliyev, Ekber [National Academy of Sciences, Institute of Physics, Baku (Azerbaijan)

2008-11-11T23:59:59.000Z

352

High power testing of the 402.5 MHZ and 805 MHZ RF windows for the spallation neutron source accelerator  

SciTech Connect

Hisorically, Radio Frequency (RF) windows have been a common point of failure in input power couplers; therefore, reliable RF windows are critical to the success of the Spallation Neutron Source (SNS) project. The normal conducting part of the SNS accelerator requires six RF windows at 402.5 MHz and eight RF windows at 805 MHz[l]. Each RF window will transmit up to 180 kW of average power and 2.5 MW peak power at 60 Hz with 1.2 millisecond pulses. The RF windows, designed and manufactured by Thales, were tested at the full average power for 4 hours to ensure no problems with the high average power and then tested to an effective forward power level of 10 MW by testing at 2.5 MW forward power into a short and varying the phase of the standing wave. The sliding short was moved from 0 to 180 degrees to ensure no arcing or breakdown problems occur in any part of the window. This paper discusses the results of the high power testing of both the 402.5 MHz and the 805 MHz RF windows. Problems encountered during testing and the solutions for these problems are discussed.

Cummings, K. A. (Karen Ann); De Baca, J. M. (John M.); Harrison, J. S. (John S.); Rodriguez, M. B. (Manuelita B.); Torrez, P. A. (Phillip A.); Warner, D. K. (David K.)

2003-01-01T23:59:59.000Z

353

Hardness variation and cyclic crystalline-amorphous phase transformation in CuZr alloy during ball milling  

E-Print Network (OSTI)

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. ...

Schoen, David Taylor

2005-01-01T23:59:59.000Z

354

RF Design and Operating Performance of the BNL/AES 1.3 GHz Single Cell Superconducting RF Photocathode Electron Gun  

SciTech Connect

Over the past several years Advanced Energy Systems and BNL have been collaborating on the development and testing of a fully superconducting photocathode electron gun. Over the past year we have begun to realize significant results which have been published elsewhere [1]. This paper will review the RF design of the gun under test and present results of its performance under various operating conditions. Results for cavity quality factor will be presented for various operating temperatures and cavity field gradients. We will also discuss future plans for testing using this gun.

Cole, Michael; Kneisel, Peter; Ben-Zvi, Ilan; Burrill, Andrew; Hahn, H.; Rao, Triveni; Zhao, Y.

2005-05-01T23:59:59.000Z

355

RF DESIGN AND OPERATING PERFORMANCE OF THE BNL/AES 1.3 GHZ SINGLE CELL SUPERCONDUCTING RF PHOTOCATHODE ELECTRON GUN.  

Science Conference Proceedings (OSTI)

Over the past several years Advanced Energy Systems and BNL have been collaborating on the development and testing of a fully superconducting photocathode electron gun. Over the past year we have begun to realize significant results which have been published elsewhere [1]. This paper will review the RF design of the gun under test and present results of its performance under various operating conditions. Results for cavity quality factor will be presented for various operating temperatures and cavity field gradients. We will also discuss future plans for testing using this gun.

COLE, M.; KNEISEL, P.; BEN-ZVI, I.; BURRILL, A.; HAHN, G.; RAO, T.; ZHAO, Y.

2005-05-16T23:59:59.000Z

356

Reducing the longitudinal emittance of the 8-GeV beam via the rf manipulation in a booster cycle  

Science Conference Proceedings (OSTI)

Bunch rotation will cause the longitudinal emittance growth whenever there are far more A rf stations than B rf stations, or vice versa. An alternate method via optimizing the RFSUM curve in a Booster cycle has been investigated using the ESME simulation. Since the rf manipulation at transition crossing can reduce the longitudinal emittance 31% and the momentum spread 17%, eventually, the rms momentum spread of 2.98 MeV and the longitudinal emittance of 0.061 eV {center_dot} sec with 95% of the beam can be achieved at 8-GeV.

Yang, Xi; Lebedev, Valeri A.; Ankenbrandt, Charles M.; /Fermilab

2005-08-01T23:59:59.000Z

357

Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses  

Science Conference Proceedings (OSTI)

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.

Kalay, Ilkay

2010-12-15T23:59:59.000Z

358

Air Oxidation Kinetics for Zr-based Alloys [Corrosion and Mechanics of  

NLE Websites -- All DOE Office Websites (Extended Search)

Air Oxidation Kinetics for Air Oxidation Kinetics for Zr-based Alloys Capabilities Materials Testing Environmentally Assisted Cracking (EAC) of Reactor Materials Corrosion Performance/Metal Dusting Overview Light Water Reactors Fatigue Testing of Carbon Steels and Low-Alloy Steels Environmentally Assisted Cracking of Ni-Base Alloys Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless Steels Steam Generator Tube Integrity Program Air Oxidation Kinetics for Zr-based Alloys Fossil Energy Fusion Energy Metal Dusting Publications List Irradiated Materials Steam Generator Tube Integrity Other Facilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Corrosion and Mechanics of Materials Light Water Reactors Bookmark and Share

359

Synthesis of bulk FeHfBO soft magnetic materials and its loss characterization at megahertz frequency  

SciTech Connect

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.

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

360

Mechanism of plutonium metal dissolution in HNO/sub 3/-HF-N/sub 2/H/sub 4/ solution  

DOE Green Energy (OSTI)

An oxidation-reduction balance of the products of the dissolution of plutonium metal and alloys in HNO/sub 3/-HF-N/sub 2/H/sub 4/ solution shows that the major reactions during dissolution are the reduction of nitrate to NH/sub 3/, N/sub 2/ and N/sub 2/O by the metal, and the oxidation of H free radicals to NH/sub 3/ by N/sub 2/H/sub 4/. Reactions between HNO/sub 3/ and N/sub 2/H/sub 4/ produce varying amounts of HN/sub 3/. The reaction rate is greater for delta-Pu than alpha-Pu, and is increased by higher concentrations of HF and HNO/sub 3/. The low yield of reduced nitrogen species indicates that nitrate is reduced on the metal surface without producing a significant concentration of species that react with N/sub 2/H/sub 4/. It is conjectured that intermediate Pu valences and electron transfer within the metal are involved. 7 refs., 3 tabs.

Karraker, D G

1985-01-01T23:59:59.000Z

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361

Separate effects identification via casting process modeling for experimental measurement of U–Pu–Zr alloys  

SciTech Connect

Computational simulations of gravity casting processes for metallic U–Pu–Zr nuclear fuel rods have been performed using a design-of-experiments technique to determine the fluid flow, liquid heat transfer, and solid heat transfer parameters which most strongly influence the process solidification speed and fuel rod porosity. The results are used to make recommendations for the best investment of experimental time and effort to measure process parameters.

J. Crapps; D. S. DeCroix; J. D. Galloway; D. A. Korzekwa; R. Aikin; R. Fielding; R. Kennedy; C. Unal

2013-11-01T23:59:59.000Z

362

High strength Sn-Mo-Nb-Zr alloy tubes and method of making same  

DOE Patents (OSTI)

Tubes for use in nuclear reactors fabricated from a quaternary alloy comprising 2.5-4.0 wt% Sn, 0.5-1.5 wt% Mo, 0.5-1.5 wt% Nb, balance essentially Zr. The tubes are fabricated by a process of hot extrusion, heat treatment, cold working to size and age hardening, so as to produce a microstructure comprising elongated .alpha. grains with an acicular transformed .beta. grain boundary phase.

Cheadle, Brian A. (Deep River, CA)

1977-01-01T23:59:59.000Z

363

Effect of nitrogen incorporation on improvement of leakage properties in high-k HfO{sub 2} capacitors treated by N{sub 2}-plasma  

Science Conference Proceedings (OSTI)

The nitrogen incorporation into the HfO{sub 2} films with an EOT (equivalent oxide thickness) of 9 A was performed by N{sub 2}-plasma to improve the electrical properties. The dielectric properties and a leakage current characteristics of the capacitors were investigated as a function of plasma power and plasma treatment temperature. The dielectric constant of the capacitors is not influenced by nitrogen incorporation. The N{sub 2}-plasma treatment at 300 deg. C and 70 W exhibits the most effective influence on improvement of the leakage current characteristics. Leakage current density of the capacitors treated at 300 deg. C and 70 W exhibits a half order of magnitude lower than that without plasma treatment. Nitrogen incorporated into the HfO{sub 2} films possesses the intrinsic effect that drastically reduce the electron leakage current through HfO{sub 2} dielectrics by deactivating the V{sub O} (oxygen vacancy) related gap states.

Seong, Nak-Jin; Yoon, Soon-Gil; Yeom, Seung-Jin; Woo, Hyun-Kyung; Kil, Deok-Sin; Roh, Jae-Sung; Sohn, Hyun-Chul [Department of Materials Science and Engineering, Chungnam National University, Daeduk Science Town, 305-764, Daejon (Korea, Republic of); Hynix Semiconductor Inc., San 136-1 Ami-ri Bubal-eub Icheon-si Kyoungki-do, 467-701 (Korea, Republic of)

2005-09-26T23:59:59.000Z

364

A Novel Zr-1Nb Alloy and a New Look at Hydriding  

Science Conference Proceedings (OSTI)

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.

Robert D. Mariani; James I. Cole; Assel Aitkaliyeva

2013-09-01T23:59:59.000Z

365

BROADBAND ANTENNA MATCHING NETWORK DESIGN AND APPLICATION FOR RF PLASMA ION SOURCE  

SciTech Connect

The RF ion source at Spallation Neutron Source has been upgraded to meet higher beam power requirement. One important subsystem for efficient operation of the ion source is the 2MHz RF impedance matching network. The real part of the antenna impedance is very small and is affected by plasma density for 2MHz operating frequency. Previous impedance matching network for the antenna has limited tuning capability to cover this potential variation of the antenna impedance since it employed a single tuning element and an impedance transformer. A new matching network with two tunable capacitors has been built and tested. This network can allow precision matching and increase the tunable range without using a transformer. A 5-element broadband matching network also has been designed, built and tested. The 5-element network allows wide band matching up to 50 kHz bandwidth from the resonance center of 2 MHz. The design procedure, simulation and test results are presented.

Shin, Ki [ORNL; Kang, Yoon W [ORNL; Piller, Chip [ORNL; Fathy, Aly [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

366

A new approach to calculate the transport matrix in RF cavities  

SciTech Connect

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.

Eidelman, Yu.; /Novosibirsk, IYF; Mokhov, N.; Nagaitsev, S.; Solyak, N.; /Fermilab

2011-03-01T23:59:59.000Z

367

A high-gradient high-duty-factor RF photo-cathode electron gun  

Science Conference Proceedings (OSTI)

We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

Robert Rimmer; N. Hartman; S. Lidia; S.H. Wang

2002-08-01T23:59:59.000Z

368

Simulations of Ion Migration in the LCLS RF Gun and Injector  

SciTech Connect

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.

Brachmann, Axel; /SLAC; Dowell, David; /SLAC

2012-06-25T23:59:59.000Z

369

Options for an 11 GeV RF Beam Separator for the Jefferson Lab CEBAF Upgrade  

Science Conference Proceedings (OSTI)

The CEBAF accelerator at Jefferson Lab has had, since first demonstration in 1996, the ability to deliver a 5-pass electron beam to experimental halls (A, B, and C) simultaneously. This capability was provided by a set of three, room temperature 499 MHz rf separators in the 5th pass beamline. The separator was two-rod, TEM mode type resonator, which has a high shunt impedance. The maximum rf power to deflect the 6 GeV beams was about 3.4kW. The 12 GeV baseline design does not preserve the capability of separating the 5th pass, 11 GeV beam for the 3 existing halls. Several options for restoring this capability, including extension of the present room temperature system or a new superconducting design in combination with magnetic systems, are under investigation and are presented.

Jean Delayen, Michael Spata, Haipeng Wang

2009-05-01T23:59:59.000Z

370

Beam loading compensation of traveling wave linacs through the time dependence of the rf drive  

SciTech Connect

Beam loading in traveling-wave linear accelerating structures leads to unacceptable spread of particle energies across an extended train of bunched particles due to beam-induced field and dispersion. Methods for modulating the rf power driving linacs are effective at reducing energy spread, but for general linacs do not have a clear analytic foundation. We report here methods for calculating how to modulate the rf drive in arbitrarily nonuniform traveling-wave linacs within the convective-transport (power-diffusion) model that results in no additional energy spread due to beam loading (but not dispersion). Varying group velocity, loss factor, and cell quality factor within a structure, and nonzero particle velocity, are handled.

Towne N.; Rose J.

2011-09-30T23:59:59.000Z

371

Advanced Photon Source RF Beam Position Monitor System Upgrade Design and Commissioning  

E-Print Network (OSTI)

This paper describes the Advanced Photon Source (APS) storage ring mono-pulse rf beam position monitor (BPM) system upgrade. The present rf BPM system requires a large dead time of 400 ns between the measured bunch and upstream bunch. The bunch pattern is also constrained by the required target cluster of six bunches of 7 mA minimum necessary to operate the receiver near the top end of the dynamic range. The upgrade design objectives involve resolving bunches spaced as closely as 100 ns. These design objectives require us to reduce receiver front-end losses and reflections. An improved trigger scheme that minimizes systematic errors is also required. The upgrade is in the final phases of installation and commissioning at this time. The latest experimental and commissioning data and results will be presented.

Lill, R; Singh, O

2001-01-01T23:59:59.000Z

372

Progress on the high-current 704 MHz superconducting RF cavity at BNL  

Science Conference Proceedings (OSTI)

The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups and results for the copper prototype. The progress with the niobium cavity fabrication will also be described.

Xu W.; Astefanous, C.; Belomestnykh, S.; Ben-Zvi, I.; et al

2012-05-20T23:59:59.000Z

373

A COMPACTRIO-BASED BEAM LOSS MONITOR FOR THE SNS RF TEST CAVE  

SciTech Connect

An RF Test Cave has been built at the Spallation Neutron Source (SNS) to be able to test RF cavities without interfering the SNS accelerator operations. In addition to using thick concrete wall to minimize radiation exposure, a Beam Loss Monitor (BLM) must abort the operation within 100 usec when the integrated radiation within the cave exceeds a threshold. We choose the CompactRIO platform to implement the BLM based on its performance, cost-effectiveness, and rapid development. Each in/output module is connected through an FPGA to provide point-by-point processing. Every 10 usec the data is acquired analyzed and compared to the threshold. Data from the FPGA is transferred using DMA to the real-time controller, which communicates to a gateway PC to talk to the SNS control system. The system includes diagnostics to test the hardware and integrates the losses in real-time. In this paper we describe our design, implementation, and results

Blokland, Willem [ORNL; Armstrong, Gary A [ORNL

2009-01-01T23:59:59.000Z

374

Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation  

Science Conference Proceedings (OSTI)

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.

Stratakis, D.; Gallardo, J.; Palmer, R.B.

2011-03-28T23:59:59.000Z

375

Carbon-Fibre-Reinforced Laminates for the Tuning Structure of the LHC RF Cavities  

E-Print Network (OSTI)

A carbon-fibre-reinforced tube is proposed for the tuning structure of the superconducting RF cavities of the Large Hadron Collider (LHC). It has a high axial stiffness and provides thermal insulation between the cold RF cavity and the tuning actuator at room temperature. The tube is subjected to a high number of mechanical load cycles, high temperature gradients, thermal cycling, and ionizing radiation. Laminate theory is applied to a simplified model of the tube for a failure analysis. Long duration fatigue tests under nominal mechanical and thermal loads were performed on two tubes. The tubes were examined before and after the fatigue tests by geometric measurements, microscopy, and ultrasonic inspection. No damage such as fibre breakage, delamination, or matrix micro cracking could be detected.

Pflanz, G; Tischhauser, Johann

1997-01-01T23:59:59.000Z

376

Robust RF Switch Yields Enhanced Communication Capabilities (ANL-IN-09-053 and ANL-IN-09-070)  

Scientists at Argonne National Laboratory have created a special radio frequency (RF) microelectromechanical system (MEMS) switch based on ultra nanocrystalline diamond (UNCD) as a dielectric that promises a next generation of military and commercial ...

377

Charge-domain signal processing of direct RF sampling mixer with discrete-time filters in Bluetooth and GSM receivers  

Science Conference Proceedings (OSTI)

RF circuits for multi-GHz frequencies have recently migrated to low-cost digital deep-submicron CMOS processes. Unfortunately, this process environment, which is optimized only for digital logic and SRAM memory, is extremely unfriendly for conventional ...

Yo-Chuol Ho; Robert Bogdan Staszewski; Khurram Muhammad; Chih-Ming Hung; Dirk Leipold; Kenneth Maggio

2006-04-01T23:59:59.000Z

378

One-dimensional hybrid simulation of the dc/RF combined driven capacitively coupled CF{sub 4} plasmas  

Science Conference Proceedings (OSTI)

We developed a one-dimensional hybrid model to simulate the dc/RF combined driven capacitively coupled plasma for CF{sub 4} discharges. The numerical results show the influence of the dc source on the plasma density distribution, ion energy distributions (IEDs), and ion angle distributions (IADs) on both RF and dc electrodes. The increase of dc voltage impels more ions with high energy to the electrode applied to the dc source, which makes the IEDs at the dc electrode shift toward higher energy and the peaks in IADs shift toward the small angle region. At the same time, it also decreases ion-energy at the RF electrode and enlarges the ion-angles which strike the RF electrode.

Wang Shuai [School of Science, Northeastern University, Shenyang 110891 (China); Xu Xiang; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2012-11-15T23:59:59.000Z

379

Exploring predistortion training algorithms in a Cartesian feedback-trained digital predistortion system for RF power amplifier linearization  

E-Print Network (OSTI)

A Cartesian feedback-trained digital predistortion system for RF power amplifier linearization offers many advantages with its combination of two different linearization techniques. This thesis describes such a system, ...

Huang, Jeffrey B

2006-01-01T23:59:59.000Z

380

Software-Defined Ultra-wideband Radio Communications: A New RF Technology for Emergency Response Applications  

SciTech Connect

Reliable wireless communication links for local-area (short-range) and regional (long-range) reach capabilities are crucial for emergency response to disasters. Lack of a dependable communication system can result in disruptions in the situational awareness between the local responders in the field and the emergency command and control centers. To date, all wireless communications systems such as cell phones and walkie-talkies use narrowband radio frequency (RF) signaling for data communication. However, the hostile radio propagation environment caused by collapsed structures and rubble in various disaster sites results in significant degradation and attenuation of narrowband RF signals, which ends up in frequent communication breakdowns. To address the challenges of reliable radio communication in disaster fields, we propose an approach to use ultra-wideband (UWB) or wideband RF waveforms for implementation on Software Defined Radio (SDR) platforms. Ultra-wideband communications has been proven by many research groups to be effective in addressing many of the limitations faced by conventional narrowband radio technologies. In addition, LLNL's radio and wireless team have shown significant success in field deployment of various UWB communications system for harsh environments based on LLNL's patented UWB modulation and equalization techniques. Furthermore, using software defined radio platform for UWB communications offers a great deal of flexibility in operational parameters and helps the radio system to dynamically adapt itself to its environment for optimal performance.

Nekoogar, F; Dowla, F

2009-10-19T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
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381

Inductive current startup in large tokamaks with expanding minor radius and rf assist  

Science Conference Proceedings (OSTI)

Auxiliary rf heating of electrons before and during the current-rise phase of a large tokamak, such as the Fusion Engineering Device (R = 4.8 m, a = 1.3 m, sigma = 1.6, B/sub T/ = 3.62 T), is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at approx. 90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10/sup 19/ m/sup -3/) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a/sub 0/ approx. = 0.2 to 0.4 m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V as opposed to approx. 100 V without rf assist). During the subsequent plasma expansion and current ramp phase, a combination of rf heating (up to 5 MW) and current profile control leads to a substantial savings in volt-seconds by: (1) minimizing the resistive flux consumption; and (2) maintaining the internal flux at or near the flat profile limit.

Borowski, S.K.

1984-02-01T23:59:59.000Z

382

Design of a new VHF RF power amplifier system for LANSCE  

Science Conference Proceedings (OSTI)

A major upgrade is replacing much of the 40 year-old proton drift tube linac RF system with new components at the Los Alamos Neutron Science Center (LANSCE). When installed, the new system will reduce the total number of electron power tubes from twenty-four to eight in the RF powerplant. A new 200 MHz high power cavity amplifier has being developed at LANSCE. This 3.2 MW final power amplifier (FPA) uses a Thales TH628 Diacrode{reg_sign}, a state-of-the-art tetrode that eliminates the large anode modulator of the triode-based FPA that has been in use for four decades. Drive power for the FPA is provided by a new tetrode intermediate power amplifier (and a solid-state driver stage). The new system has sufficient duty-factor capability to allow LANSCE to return to 1 MW beam operation. Prototype RF power amplifiers have been designed, fabricated, and assembled, and are being tested. High voltage DC power became available through innovative re-engineering of an installed system. Details of the electrical and mechanical design of the FPA and ancillary systems are discussed.

Lyles, John T M [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

383

HIGH POWER TEST OF RF SEPARATOR FOR 12 GEV UPGRADE OF CEBAF AT JLAB  

Science Conference Proceedings (OSTI)

CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, we are exploring the possibility of extension of existing normal conducting 499 MHz TEM-type rf separator cavities. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test of 4 kW confirms that the cavity meet the requirement.

S. Ahmed, M. Wissmann, J. Mammosser, C. Hovater, M. Spata, G. Krafft, J. Delayen

2012-07-01T23:59:59.000Z

384

Integrated design and analysis of rf heating and current drive systems  

SciTech Connect

The design, analysis, and performance evaluation of rf power systems ultimately requires accurate modeling of a chain of subsystems starting with the rf transmitter and ending with the power absorption in the plasma. A collection of computer codes is used at ORNL to calculate the plasma loading and wave spectrum for a three-dimensional rf antenna, the transmission/reflection properties of the Faraday shield and its effect on the electrical characteristics and phase velocity of the antenna, the internal coupling among antenna array components and the incorporation of the antenna array into a transmission line model of the phase control, tuning, matching, and power distribution system. Some codes and techniques are more suited for the rapid evaluation of system design progressions, while others are more applicable to the detailed analysis of final designs or existing hardware. The interaction of codes and the accuracy of calculations will be illustrated by the process of determining the plasma loading as a function of phasing and density profiles for the TFTR ICRH antennas and comparing the results to measurements. An example of modeling a complex antenna geometry will be the comparison of calculations with the measured electrical response of a four-strap mockup of the JET A2 antenna array which was loaned to ORNL by the JET ICRH team.

Ryan, P.M.; Carter, M.D.; Goulding, R.H. [and others

1995-09-01T23:59:59.000Z

385

The Development of RF Heating of Magnetically Confined Deuterium-Tritium Plasmas  

SciTech Connect

The experimental and theoretical development of ion cyclotron radiofrequency heating (ICRF) in toroidal magnetically-confined plasmas recently culminated with the demonstration of ICRF heating of D-T plasmas, first in the Tokamak Fusion Test Reactor (TFTR) and then in the Joint European Torus (JET). Various heating schemes based on the cyclotron resonances between the plasma ions and the applied ICRF waves have been used, including second harmonic tritium, minority deuterium, minority helium-3, mode conversion at the D-T ion-ion hybrid layer, and ion Bernstein wave heating. Second harmonic tritium heating was first shown to be effective in a reactor-grade plasma in TFTR. D-minority heating on JET has led to the achievement of Q = 0.22, the ratio of fusion power produced to RF power input, sustained over a few energy confinement times. In this paper, some of the key building blocks in the development of rf heating of plasmas are reviewed and prospects for the development of advanced methods of plasma control based on the application of rf waves are discussed.

B.P. LeBlanc; C.K. Phillips; J.C. Hosea; R. Majeski; S. Bernabei [and others

1999-06-01T23:59:59.000Z

386

Use of a Geographic Mapping Tool in Power Line Routing for RF Hazard Identification: A Feasibility Evaluation  

Science Conference Proceedings (OSTI)

Radiofrequency (RF) fields induce currents and voltages on conductive objects with the general finding that larger or longer or taller objects, such as power lines and tall cranes, can result in greater currents and voltages. Medium wave frequencies (MF) associated with operation of AM radio broadcast stations are particularly prone to induction of RF voltages on long and/or tall cables that present the potential for arcing to ground or personnel who may initiate contact with the conductor. MF includes t...

2011-11-16T23:59:59.000Z

387

Realization of high-quality HfO{sub 2} on In{sub 0.53}Ga{sub 0.47}As by in-situ atomic-layer-deposition  

Science Conference Proceedings (OSTI)

High {kappa} dielectric of HfAlO/HfO{sub 2} was an in-situ atomic-layer-deposited directly on molecular beam epitaxy grown In{sub 0.53}Ga{sub 0.47}As surface without using pre-treatments or interfacial passivation layers, where HfAlO (HfO{sub 2}:Al{sub 2}O{sub 3} {approx} 4:1) with high re-crystallization temperature was employed as the top oxide layer. The HfAlO ({approx}4.5 nm)/HfO{sub 2} (0.8 nm)/In{sub 0.53}Ga{sub 0.47}As metal oxide semiconductor capacitors have exhibited an oxide/In{sub 0.53}Ga{sub 0.47}As interface free of arsenic-related defective bonding, thermodynamic stability at 800 deg. C, and low leakage current densities of oxide thickness of less than 1 nm has been achieved by reducing the HfAlO thickness to {approx}2.7 nm with the same initial HfO{sub 2} thickness of {approx}0.8 nm.

Lin, T. D.; Hong, M. [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Y. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, C. A.; Huang, M. L.; Lee, W. C. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

2012-04-23T23:59:59.000Z

388

Formation of tetragonal or monoclinic ZrO{sub 2} coatings by oxygen plasma treatment of Zr{sub 74.7}Cu{sub 19.7}Nb{sub 5.6} glassy thin films  

Science Conference Proceedings (OSTI)

The authors report on the production of stable nanostructured tetragonal and/or monoclinic ZrO{sub 2} nanopillars achieved by means of oxygen plasma treatment of ternary Zr{sub 74.7}Cu{sub 19.7}Nb{sub 5.6} glassy films. The Zr-based metallic glass thin films were successfully deposited by magnetron sputtering and subsequently subjected to oxygen plasma for various exposure times. The compositions of the oxidized films were determined by Auger electron spectroscopy and X-Ray photoelectron spectroscopy depth profiling while the surface morphology was evaluated by means of atomic force microscopy and scanning electron microscopy. X-Ray diffraction was used for the structural analysis. Our results show that, depending on the length of time of oxygen plasma treatment, tetragonal and/or monoclinic ZrO{sub 2} films can be formed, the surface morphology of which exhibit nanopillar structures with an increased effective surface. These findings provide an easy and efficient way for growing ZrO{sub 2} coatings with a predefined structure suitable for protective and possibly for catalytic applications.

Panagiotopoulos, N. T.; Kovac, J.; Mozetic, M.; Patsalas, P.; Evangelakis, G. A. [University of Ioannina, Department of Physics, Ioannina 45110 (Greece); Department of Surface Engineering and Optoelectronics, Jozef Stefan Institute, Ljubljana 1000 (Slovenia); University of Ioannina, Department of Materials Science and Engineering, Ioannina 45110 (Greece); University of Ioannina, Department of Physics, Ioannina 45110 (Greece)

2011-09-15T23:59:59.000Z

389

Phase transformation of "chem-prep" PZT 95/5-2Nb HF1035 ceramic under quasi-static loading conditions.  

SciTech Connect

Specimens of poled and unpoled ''chem-prep'' PNZT ceramic from batch HF1035 were tested under hydrostatic, uniaxial, and constant stress difference loading conditions at -55, 25, and 75 C. The objective of this experimental study was to characterize the mechanical properties and conditions for the ferroelectric (FE) to antiferroelectric (AFE) phase transformations of this ''chem-prep'' PNZT ceramic to aid grain-scale modeling efforts in developing and testing realistic response models for use in simulation codes. As seen from a previously characterized material (batch HF803), poled ceramic from HF1035 was seen to undergo anisotropic deformation during the transition from a FE to an AFE phase. Also, the phase transformation was found to be permanent for the two low temperature conditions, whereas the transformation can be completely reversed at the highest temperature. The rates of increase in the phase transformation pressures with temperature were practically identical for both unpoled and poled PNZT HF1035 specimens. We observed that temperature spread the phase transformation over mean stress analogous to the observed spread over mean stress due to shear stress. Additionally, for poled ceramic samples, the FE to AFE phase transformation was seen to occur when the normal compressive stress, acting perpendicular to a crystallographic plane about the polar axis, equals the hydrostatic pressure at which the transformation otherwise takes place.

Montgomery, Stephen Tedford; Lee, Moo Yul; Meier, Diane A.; Hofer, John H.

2006-07-01T23:59:59.000Z

390

GEOPHYSICAL RESEARCH LETTERS, VOL. 26, NO. 6, PAGES 667-670, MARCH 15, 1999 Observation of topside ionospheric MF/HF radio  

E-Print Network (OSTI)

ionospheric MF/HF radio emission from space S. D. Bale Space Sciences Laboratory, University of California `auroral roar', although to propa- gate to the spacecraft they must have been generated above spectrum as viewed from space. Introduction Observations of ionospheric radio emission in the MF (0.3-3 MHz

California at Berkeley, University of

391

Band offsets of Al{sub 2}O{sub 3} and HfO{sub 2} oxides deposited by atomic layer deposition technique on hydrogenated diamond  

SciTech Connect

High-k oxide insulators (Al{sub 2}O{sub 3} and HfO{sub 2}) have been deposited on a single crystalline hydrogenated diamond (H-diamond) epilayer by an atomic layer deposition technique at temperature as low as 120 Degree-Sign C. Interfacial electronic band structures are characterized by X-ray photoelectron spectroscopy. Based on core-level binding energies and valence band maximum values, valence band offsets are found to be 2.9 {+-} 0.2 and 2.6 {+-} 0.2 eV for Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions, respectively. Band gaps of the Al{sub 2}O{sub 3} and HfO{sub 2} have been determined to be 7.2 {+-} 0.2 and 5.4 {+-} 0.2 eV by measuring O 1s energy loss spectra, respectively. Both the Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions are concluded to be type-II staggered band configurations with conduction band offsets of 1.2 {+-} 0.2 and 2.7 {+-} 0.2 eV, respectively.

Liu, J. W.; Liao, M. Y.; Imura, M. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Koide, Y. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Center of Materials Research for Low Carbon Emission, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2012-12-17T23:59:59.000Z

392

Light-induced structural changes in Eu-doped (Pb,La)(Zr,Ti)O{sub 3} ceramics  

SciTech Connect

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.

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

393

Influence of projectile neutron number in the {sup 208}Pb({sup 48}Ti, n){sup 255}Rf and {sup 208}Pb({sup 50}Ti, n){sup 257}Rf reactions  

Science Conference Proceedings (OSTI)

Four isotopes of rutherfordium, {sup 254-257}Rf, were produced by the {sup 208}Pb({sup 48}Ti, xn){sup 256-x}Rf and {sup 208}Pb({sup 50}Ti, xn){sup 258-x}Rf reactions (x=1,2) at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Excitation functions were measured for the 1n and 2n exit channels. A maximum likelihood technique, which correctly accounts for the changing cross section at all energies subtended by the targets, was used to fit the 1n data to allow a more direct comparison between excitation functions obtained under different experimental conditions. The maximum 1n cross sections of the {sup 208}Pb({sup 48}Ti, n){sup 255}Rf and {sup 208}Pb({sup 50}Ti, n){sup 257}Rf reactions obtained from fits to the experimental data are 0.38{+-}0.07 nb and 40{+-}5 nb, respectively. Excitation functions for the 2n exit channel were also measured, with maximum cross sections of 0.40{sub -0.17}{sup +0.27} nb for the {sup 48}Ti induced reaction, and 15.7{+-}0.2 nb for the {sup 50}Ti induced reaction. The impact of the two neutron difference in the projectile on the 1n cross section is discussed. The results are compared to the Fusion by Diffusion model developed by Swiatecki, Wilczynska, and Wilczynski.

Dragojevic, I.; Garcia, M. A.; Gates, J. M.; Nelson, S. L.; Nitsche, H. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Gregorich, K. E.; Stavsetra, L.; Sudowe, R. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Duellmann, Ch. E. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Abteilung Kernchemie, Gesellschaft fuer Schwerionenforschung mbH, D-64291 Darmstadt (Germany)

2008-08-15T23:59:59.000Z

394

RF tests of an 805 MHz pillbox cavity at Lab G of Fermilab  

SciTech Connect

We report recent high power RF tests on an 805 MHz RF pillbox cavity with demountable windows for beam apertures at Lab G of Fermilab, a dedicated facility for testing of MUCOOL (muon cooling) components. The cavity is installed inside a superconducting solenoidal magnet. A 12 MW peak RF power klystron is used for the tests. The cavity has been processed both with and without magnetic field. Without magnetic field, a gradient of 34 MV/m was reached rather quickly with very low sparking rate. In a 2.5 T solenoidal field, a 16 MV/m gradient was achieved, and it had to take many weeks of conditioning. Strong multipacting effects associated with high radiation levels were measured during the processing with the magnetic field. More recently Be windows with TiN-coated surface have been installed and tested at conditions of with and without the external magnetic field. A conservative 16 MV/m gradient without magnetic field was reached quickly as planned. Less multipacting was observed during the conditioning, it indicated that the TiN-coated surface on the windows had indeed helped to reduce the secondary electron emissions significantly. A modest gradient of 16.5 MV/m was finally achieved with magnet on in solenoidal mode and the field up to 4 T. Preliminary inspection on Be windows surface found no damage at all, in comparison with Cu windows where substantial surface damage was found. Preliminary understanding of conditioning cavity in a strong magnetic field has been developed. More through window and cavity surface inspection is under way.

Li, Derun; Corlett, J.; MacGill, R.; Wallig, J.; Zisman, M.; Moretti, A.; Qian , Z.; Wu, V.; Rimmer, R.; Norem, J.; Torun, Y.

2003-05-01T23:59:59.000Z

395

Beta-decay properties of Zr and Mo neutron-rich isotopes  

E-Print Network (OSTI)

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.

Sarriguren, P

2010-01-01T23:59:59.000Z

396

Design of traveling wave windows for the PEP-II RF coupling network  

SciTech Connect

The waveguide windows in the PEP-II RF coupling network have to withstand high power of 500 kW. Traveling wave windows have lower power dissipation than conventional self-matched windows, thus rendering the possibility of less stringent mechanical design. The traveling wave behavior is achieved by providing a reflecting iris on each side of the window, and depending on the configuration of the irises, traveling wave windows are characterized as inductive or capacitive types. A numerical design procedure using MAFIA has been developed for traveling wave windows. The relative advantages of inductive and capacitive windows are discussed. Furthermore, the issues of bandwidth and multipactoring are also addressed.

Kroll, N.M.; Ng, C.K.; Judkins, J.; Neubauer, M.

1995-05-01T23:59:59.000Z

397

Rf-plasma synthesis of nanosize silicon carbide and nitride. Final report  

DOE Green Energy (OSTI)

A pulsed rf plasma technique is capable of generating ceramic particles of 10 manometer dimension. Experiments using silane/ammonia and trimethylchlorosilane/hydrogen gas mixtures show that both silicon nitride and silicon carbide powders can be synthesized with control of the average particle diameter from 7 to 200 nm. Large size dispersion and much agglomeration appear characteristic of the method, in contrast to results reported by another research group. The as produced powders have a high hydrogen content and are air and moisture sensitive. Post-plasma treatment in a controlled atmosphere at elevated temperature (800{degrees}C) eliminates the hydrogen and stabilizes the powder with respect to oxidation or hydrolysis.

Buss, R.J.

1997-02-01T23:59:59.000Z

398

Optical diagnostics for a high power, rf-inductively coupled plasma  

SciTech Connect

Emission spectroscopy and laser-induced fluorescence have been used to monitor the field and tail-flame regions of a Hull-design inductively coupled plasma. This plasma is used for a variety of syntheses including SiC, TiC, BN, A1N and diamond. Temporally- and spatially-resolved spectra of both pure Ar and Ar/gas mixtures have been studied as a function of RF power, pressure and flow rate. Preliminary data suggest that the system is far from local thermodynamic equilibrium.

Nogar, N.S.; Keaton, G.L.; Anderson, J.E.; Trkula, M.

1988-01-01T23:59:59.000Z

399

efA. r rrOea IWIt 5/rf 5eh/#,tz-  

E-Print Network (OSTI)

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Washington at Seattle, University of

400

RF Conditioning and testing of fundamental power couplers for the RIA project  

DOE Green Energy (OSTI)

The Rare Isotope Accelerator (RIA) is the highest priority of the nuclear physics community in the United States for a major new accelerator facility. A principal element of RIA will be a superconducting 1.4 GeV superconducting ion linac accelerating ions of isotopes from hydrogen to uranium onto production targets or for further acceleration by a second superconducting linac. The superconducting linac technology is closely related to that used at existing accelerators and the Spallation Neutron Source. Taking advantage of JLAB's SRF Institute facilities and expertise for the SNS project, preparation of couplers, RF conditioning and high power tests have been performed on fundamental power couplers for RIA project.

M. Stirbet; J. Popielarski; T. L. Grimm; M. Johnson

2003-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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to obtain the most current and comprehensive results.


401

Structural and optical properties of zinc oxide film using RF-sputtering technique  

Science Conference Proceedings (OSTI)

This paper reports the fabrication of zinc oxide (ZnO) film using RF-sputtering technique. Determination of the structural properties using High Resolution X-ray Diffraction (HRXRD) confirmed that ZnO film deposited on silicon (Si) substrate has a high quality. This result is in line with the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) which were used to image the morphology of the film, in which a rough surface was demonstrated. Photoluminescence (PL) emission is included to study the optical properties of ZnO film that shows two PL peak in the UV region at 371 nm and in visible region at 530 nm respectively.

Hashim, A. J.; Jaafar, M. S.; Ghazai, Alaa J. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Pinang (Malaysia); Physics Department, Science College, Thi-Qar University (Iraq)

2012-11-27T23:59:59.000Z

402

Synthesis of Zr Doped NiO Layers on NiSi2 Linling Gu/Si-MCP Structures for Supercapacitors  

Science Conference Proceedings (OSTI)

Three-dimensional super capacitors consisting of NiSi2/silicon micro channel plates (MCPs) with Zr doped NiO layers have been fabricated. The silicon MCPs produced by electrochemical etching is utilized as a backbone of the 3D structure. Nickle layer ... Keywords: Zr doped NiO, Electrochemical properties, Silicon microchannel plate

Linling Gu; Tao Liu; Fei Wang; Shaohui Xu; Lianwei Wang; Paul K. Chu

2012-04-01T23:59:59.000Z

403

Fundamental science investigations to develop a 6-MV laser triggered gas switch for ZR: first annual report.  

Science Conference Proceedings (OSTI)

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.

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

404

Determination of the displacement energy of O, Si and Zr under electron beam irradiation  

Science Conference Proceedings (OSTI)

The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

Edmondson, Philip D [ORNL; Weber, William J [ORNL; Namavar, Fereydoon [University of Nebraska Medical Center; Zhang, Yanwen [ORNL

2012-01-01T23:59:59.000Z

405

Mechanical Design and Fabrication of a New RF Power Amplifier for LANSCE  

SciTech Connect

A Full-scale prototype of a new 201.25 MHz RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, assembled and installed in the test facility. This prototype was successfully tested and met the physics and electronics design criteria. The team faced design and manufacturing challenges, having a goal to produce 2 MW peak power at 13% duty factor, at the elevation of over 2 km in Los Alamos. The mechanical design of the final power amplifier was built around a Thales TH628 Diacrode{sup R}, a state-of-art tetrode power tube. The main structure includes Input circuit, Output circuit, Grid decoupling circuit, Output coupler, Tuning pistons, and a cooling system. Many types of material were utilized to make this new RF amplifier. The fabrication processes of the key components were completed in the Prototype Fabrication Division shop at Los Alamos National Laboratory. The critical plating procedures were achieved by private industry. The FPA mass is nearly 600 kg and installed in a beam structural support stand. In this paper, we summarize the FPA design basis and fabrication, plating, and assembly process steps with necessary lifting and handling fixtures. In addition, to ensure the quality of the FPA support structure a finite element analysis with seismic design forces has also been carried out.

Chen, Zukun [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

406

Mechanical and thermal analysis of beryllium windows for RF cavities in a muon cooling channel  

SciTech Connect

Thin beryllium windows (foils) may be utilized to increase shunt impedance of closed-cell RF cavities. These windows are subject to ohmic heating from RF currents. The resulting temperature gradients in the windows can produce out of plane displacements that detune the cavity frequency. The window displacement can be reduced or eliminated by pre-stressing the foils in tension. Because of possible variations during manufacture, it is important to quantify the actual prestress of a Be window before it is put into service. We present the thermal and mechanical analyses of such windows under typical operating conditions and describe a simple non-destructive means to quantify the pre-stress using the acoustic signature of a window. Using finite element analysis, thin plate theory and physical measurements of the vibration modes of a window we attempted to characterize the actual Be window pre-stress in a small number of commercially sourced windows (30% of yield strength is typical). This method can be used for any window material and size, but this study focused on 16 cm diameter Be Windows ranging in thickness from 125 microns to 508 microns and with varying pre-stresses. The method can be used to nondestructively test future Be windows for the desired prestress.

Li, Derun; Ladran, A.; Lozano, D.; Rimmer, R.

2002-05-30T23:59:59.000Z

407

Active high-power RF pulse compression using optically switched resonant delay lines  

DOE Green Energy (OSTI)

The authors present the design and a proof of principle experimental results of an optically controlled high power rf pulse compression system. The design should, in principle, handle few hundreds of Megawatts of power at X-band. The system is based on the switched resonant delay line theory. It employs resonant delay lines as a means of storing rf energy. The coupling to the lines is optimized for maximum energy storage during the charging phase. To discharge the lines, a high power microwave switch increases the coupling to the lines just before the start of the output pulse. The high power microwave switch, required for this system, is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE{sub 01} mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability.

Tantawi, S.G.; Ruth, R.D.; Vlieks, A.E. [Stanford Univ., CA (US). Stanford Linear Accelerator Center; Zolotorev, M. [Lawrence Berkeley National Lab., CA (US)

1996-11-01T23:59:59.000Z

408

R.F. heating near the lower hybrid frequency in the FM-1 spherator  

SciTech Connect

Plasma heating experiments at frequencies near the lower hybrid frequency have been carried out at modest powers (.05 to 4kW). The antenna structure operating at 68 MHz was comprised of two plates driven out of phase on the exterior of the plasma. High electron heating efficiency (greater than 40 percent) in both helium and argon plasmas was observed with only a weak density dependence. At low densities (n/sub e/ less than or equal to 1 x 10$sup 11$ cm$sup -3$), the heating was uniform across the plasma while at higher densities the heating was preferentially on the exterior portion of the plasma. The heating of the exterior of the plasma was found not to correspond to absorption at the lower hybrid resonance layer. The electron heating efficiency was found to be a weak function of rf power when the incident rf power was varied from 1 to 15 times the experimentally observed threshold power for parametric instabilities. Ion temperatures were determined by measuring the Doppler broadening of an Argon ion line using a Fabry-Perot interferometer. Low efficiency main body ion heating (1 to 3 percent) was observed. (auth)

Hawryluk, R.J.; Davis, S.L.; Schmidt, J.A.

1975-12-01T23:59:59.000Z

409

Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab  

Science Conference Proceedings (OSTI)

The Advanced Superconducting Test Accelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beam lines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750 MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

Leibfritz, J.; Andrews, R.; Baffes, C.M.; Carlson, K.; Chase, B.; Church, M.D.; Harms, E.R.; Klebaner, A.L.; Kucera, M.; Martinez, A.; Nagaitsev, S.; /Fermilab

2012-05-01T23:59:59.000Z

410

Electromagnetic Design of RF Cavities for Accelerating Low-Energy Muons  

Science Conference Proceedings (OSTI)

A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications. The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings decay muons, which initially have kinetic energies mostly around 15-20 MeV, to 200 MeV over a distance of {approx}10 m. At this energy, both ionization cooling and further, more conventional acceleration of the muon beam become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM{sub 010}) RF cavities with wide beam apertures closed by thin conducting edge-cooled windows. Electromagnetic design of the cavity, including its RF coupler, tuning and vacuum elements, and field probes, has been developed with the CST MicroWave Studio, and is presented.

Kurennoy, Sergey S. [Los Alamos National Laboratory

2012-05-14T23:59:59.000Z

411

Experimental Estimate of Beam Loading and Minimum rf Voltage for Acceleration of High Intensity Beam in the Fermilab Booster  

E-Print Network (OSTI)

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Yang, X; Norem, J; Yang, Xi

2004-01-01T23:59:59.000Z

412

Experimental estimate of beam loading and minimum rf voltage for acceleration of high intensity beam in the Fermilab Booster  

SciTech Connect

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Xi Yang; Charles M Ankenbrandt and Jim Norem

2004-04-01T23:59:59.000Z

413

Fuel element design for the enhanced destruction of plutonium in a nuclear reactor  

DOE Patents (OSTI)

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.

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

414

Fuel element design for the enhanced destruction of plutonium in a nuclear reactor  

DOE Patents (OSTI)

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.

Crawford, Douglas C.; Porter, Douglas L.; Hayes, Steven L.; Hill, Robert N.

1997-12-01T23:59:59.000Z

415

Fuel element design for the enhanced destruction of plutonium in a nuclear reactor  

DOE Patents (OSTI)

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.

Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Hill, R.N.

1999-03-23T23:59:59.000Z

416

CRYSTALLINE-TO-AMORPHOUS TRANSFORMATION OF INTERMETALLIC COMPOUNDS IN THE ZR-FE-M SYSTEM INDUCED BY IRRADIATION  

E-Print Network (OSTI)

such alloys are Zircaloy- 2 used in BWR, Zircaloy-4 used in PWR, the Canadian Zr-2.5%Nb used in CANDU pressure predict- able. This is especially true for high-fluence components, such as pressure tubes in CANDU

Motta, Arthur T.

417

500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application  

SciTech Connect

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

Chu, Tak Sum; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore; Barty, Christopher; /LLNL, Livermore; Gibson, David; /LLNL, Livermore; Hartemann, Fred; /LLNL, Livermore; Marsh, Roark; /LLNL, Livermore; Siders, Craig; /LLNL, Livermore; Adolphsen, Chris; /SLAC; Jongewaard, Erik; /SLAC; Raubenheimer, Tor; /SLAC; Tantawi, Sami; /SLAC; Vlieks, Arnold; /SLAC; Wang, Juwen; /SLAC

2012-07-03T23:59:59.000Z

418

500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION  

Science Conference Proceedings (OSTI)

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This high power RF system is being designed and constructed. In this paper, we will present the design, layout, and status of this RF system.

Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C; Barty, C P; Adolphsen, C; Jongewaard, E; Tantawi, S; Vlieks, A; Wang, J W; Raubenheimer, T

2010-05-12T23:59:59.000Z

419

Deposition of Dense SiO2 Thin Films for Electrical Insulation Applications by Microwave ECR Plasma Source Enhanced RF Reactive Magnetron Sputtering  

Science Conference Proceedings (OSTI)

Silicon dioxide thin films have been deposited successfully on high speed steel (HSS) cutting tool substrates by means of microwave electron cyclotron resonance (MW-ECR) plasma source enhanced RF reactive magnetron sputtering of a pure silica target ... Keywords: SiO2 thin films, Electrical insulation properties, RF magnetron sputtering, Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS)

Qiyong Zeng; Xiaofeng Zheng; Zhonghua Yu; Yunxian Cui

2010-03-01T23:59:59.000Z

420

Spectroscopic differentiation between O-atom vacancy and divacancy defects, respectively, in TiO2 and HfO2 by X-ray absorption spectroscopy  

Science Conference Proceedings (OSTI)

Defect state features have been detected in second derivative O K edge spectra for thin films of nano-crystalline TiO"2 and HfO"2. Based on soft X-ray photoelectron band edge spectra, and the occurrence of occupied band edge 4f states in Gd(Sc,Ti)O"3, ... Keywords: Bound resonance states, Divacancies, Immobile and mobile vacancies, Monovacancies, Pre-edge regime, X-ray absorption spectroscopy

G. Lucovsky; K. -B. Chung; J. -W. Kim; D. Norlund

2009-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Proc. of the workshop on pushing the limits of RF superconductivity.  

Science Conference Proceedings (OSTI)

For three days in late September last year, some sixty experts in RF superconductivity from around the world came together at Argonne to discuss how to push the limits of RF superconductivity for particle accelerators. It was an intense workshop with in-depth presentations and ample discussions. There was added excitement due to the fact that, a few days before the workshop, the International Technology Recommendation Panel had decided in favor of superconducting technology for the International Linear Collider (ILC), the next major high-energy physics accelerator project. Superconducting RF technology is also important for other large accelerator projects that are either imminent or under active discussion at this time, such as the Rare Isotope Accelerator (RIA) for nuclear physics, energy recovery linacs (ERLs), and x-ray free-electron lasers. For these accelerators, the capability in maximum accelerating gradient and/or the Q value is essential to limit the length and/or operating cost of the accelerators. The technological progress of superconducting accelerators during the past two decades has been truly remarkable, both in low-frequency structures for acceleration of protons and ions as well as in high-frequency structures for electrons. The requirements of future accelerators demand an even higher level of performance. The topics of this workshop are therefore highly relevant and timely. The presentations given at the workshop contained authoritative reviews of the current state of the art as well as some original materials that previously had not been widely circulated. We therefore felt strongly that these materials should be put together in the form of a workshop proceeding. The outcome is this report, which consists of two parts: first, a collection of the scholarly papers prepared by some of the participants and second, copies of the viewgraphs of all presentations. The presentation viewgraphs, in full color, are also available from the Workshop Presentations link on the workshop's web page at http://www.aps.anl.gov/conferences/RFSCLimits/. I would like to thank all of the participants for their lively contributions to the workshop and to these proceedings, and Helen Edwards and Hasan Padamsee for their help in developing the workshop program. I also thank Cathy Eyberger, Kelly Jaje, and Renee Lanham for working very hard to take care of the administrative details, in particular Cathy for editing this report.

Kim, K-J., Eyberger, C., editors

2005-04-13T23:59:59.000Z

422

Development of a CW Superconducting RF Booster Cryomodule for Future Light Sources  

Science Conference Proceedings (OSTI)

Future light sources based on seeded free electron lasers (FEL) have the potential to increase the soft xray flux by several orders of magnitude with short bunch lengths to probe electron structure and dynamics. A low emittance, high rep-rate radio frequency (RF) photocathode electron gun will generate the electron beam that will require very stringent beam control and manipulation through the superconducting linear accelerator to maintain the high brightness required for an x-ray FEL. The initial or booster cavities of the superconducting radio frequency (SRF) linear accelerator will require stringent control of transverse kicks and higher order modes (HOM) during the beam manipulation and conditioning that is needed for emittance exchange and bunch compression. This SBIR proposal will develop, fabricate and test a continuous-wave SRF booster cryomodule specifically for this application. Phase I demonstrated the technical feasibility of the project by completing the preliminary SRF cavity and cryomodule design and its integration into an R&D test stand for beam studies at Lawrence Berkeley National Laboratory (LBNL). The five-cell bulk niobium cavities operate at 750 MHz, and generate 10 MV each with strong HOM damping and special care to eliminate transverse kicks due to couplers. Due to continuous-wave operation at fairly modest beam currents and accelerating gradients the complexity of the two cavity cryomodule is greatly reduced compared to an ILC type system. Phase II will finalize the design, and fabricate and test the booster cryomodule. The cryomodule consists of two five-cell cavities that will accelerate megahertz bunch trains with nano-coulomb charge. The accelerating gradient is a very modest 10 MV/m with peak surface fields of 20 MV/m and 42.6 mT. The cryogenic system operates at 2 K with a design dynamic load of 20 W and total required cryogenic capacity of 45 W. The average beam current of up to 1 mA corresponds to a beam power of 10 kW per 5- cell cavity and will require 20 kW of RF power for transmission, control and regulation. The RF power will be supplied by a commercial tetrode. Cryogenic tests will be carried out at LBNL to make use of their test facilities, cryogenics and laser systems, and for future use with beam. Demonstration of this new type of booster cryomodule will open many new applications of SRF linear accelerators.

Grimm, Terry L; Bogle, Andrew; Deimling, Brian; Hollister, Jerry; II, Randall Jecks; Kolka, Ahren; Romel, Chandra

2009-04-13T23:59:59.000Z

423

Multinucleon transfer reactions for the {sup 28}Si+{sup 90,94}Zr systems in the region below and near the Coulomb barrier  

Science Conference Proceedings (OSTI)

Measurements on multinucleon transfer reactions for {sup 28}Si+{sup 90,94}Zr systems were performed at sub- and near-barrier energies. The fact that {sup 90}Zr has a closed neutron shell (N = 50) and {sup 94}Zr has four neutrons outside the closed shell, allows us to investigate the effects of shell closure and pairing correlation on multinucleon transfer mechanism. The experiment was performed with pulsed {sup 28}Si beam using the Heavy Ion Reaction Analyzer (HIRA) at Inter University Accelerator Centre (IUAC), New Delhi. Based on the Q-value considerations, it turned out that pickup channels were neutron transfer whereas stripping channels were proton transfer. For the {sup 28}Si+{sup 90}Zr system, the values of the slope parameter for two-neutron pickup turned out to be less than that for one-neutron pickup. The values of the slope parameter were almost the same for two-, three-, and four-neutron pickup channels in the case of the {sup 28}Si+{sup 94}Zr system. The transfer probabilities in the case of the {sup 28}Si+{sup 94}Zr system were much larger than those for the {sup 28}Si+{sup 90}Zr system, further supporting the fact that there is a correlation between the transfer channels and sub-barrier fusion cross-section enhancement. An odd-even staggering was observed in the extracted transfer probabilities at the barrier radius implying the role of pairing correlation in transfer reactions.

Kalkal, Sunil; Mandal, S.; Garg, Ritika; Saxena, Mansi; Goyal, Savi; Verma, S.; Kumar, Suresh; Singh, R. [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Madhavan, N.; Jhingan, A.; Nath, S.; Gehlot, J.; Mohanto, Gayatri [Inter University Accelerator Centre, New Delhi (India); Prasad, E. [Department of Physics, Calicut University, Kerala (India); Sandal, Rohit; Behera, B. R. [Department of Physics, Panjab University, Chandigah (India); Pramanik, U. D. [Saha Institute of Nuclear Physics, Kolkata (India); Sinha, A. K. [UGC-DAE Consortium for Scientific Research, Kolkata (India)

2011-05-15T23:59:59.000Z

424

Pre- and post-irradiation characterization and properties measurements of ZrC coated surrogate TRISO particles  

SciTech Connect

Zirconium carbide is a candidate to either replace or supplement silicon carbide as a coating material in TRISO fuel particles for high temperature gas-cooled reactor fuels. Six sets of ZrC coated surrogate microsphere samples, fabricated by the Japan Atomic Energy Agency using the fluidized bed chemical vapor deposition method, were irradiated in the High Flux Isotope Reactor at the Oak Ridge National Laboratory. These developmental samples available for the irradiation experiment were in conditions of either as-fabricated coated particles or particles that had been heat-treated to simulate the fuel compacting process. Five sets of samples were composed of nominally stoichiometric compositions, with the sixth being richer in carbon (C/Zr = 1.4). The samples were irradiated at 800 and 1250 C with fast neutron fluences of 2 and 6 dpa. Post-irradiation, the samples were retrieved from the irradiation capsules followed by microstructural examination performed at the Oak Ridge National Laboratory's Low Activation Materials Development and Analysis Laboratory. This work was supported by the US Department of Energy Office of Nuclear Energy's Advanced Gas Reactor program as part of International Nuclear Energy Research Initiative collaboration with Japan. This report includes progress from that INERI collaboration, as well as results of some follow-up examination of the irradiated specimens. Post-irradiation examination items included microstructural characterization, and nanoindentation hardness/modulus measurements. The examinations revealed grain size enhancement and softening as the primary effects of both heat-treatment and irradiation in stoichiometric ZrC with a non-layered, homogeneous grain structure, raising serious concerns on the mechanical suitability of these particular developmental coatings as a replacement for SiC in TRISO fuel. Samples with either free carbon or carbon-rich layers dispersed in the ZrC coatings experienced negligible grain size enhancement during both heat treatment and irradiation. However, these samples experienced irradiation induced softening similar to stoichiometric ZrC samples.

Vasudevamurthy, Gokul [ORNL; Katoh, Yutai [ORNL; Hunn, John D [ORNL; Snead, Lance Lewis [ORNL

2010-09-01T23:59:59.000Z

425

A high sensitivity ultralow temperature RF conductance and noise measurement setup  

SciTech Connect

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies.

Parmentier, F. D.; Mahe, A.; Denis, A.; Berroir, J.-M.; Glattli, D. C.; Placais, B.; Feve, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS UMR 8551, Universite P. et M. Curie, Universite D. Diderot 24, rue Lhomond, 75231 Paris Cedex 05 (France)

2011-01-15T23:59:59.000Z

426

Multi-purpose 805 MHz Pillbox RF Cavity for Muon Acceleration Studies  

SciTech Connect

An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques. The cavity can operate at vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity is designed for easy assembly and disassembly with bolted construction using aluminum seals. The surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. Different surface treatments such as electro polished, high-pressure water cleaned, and atomic layer deposition are being considered for testing. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. Current status of the cavity prepared for initial conditioning and operation in the external magnetic field is discussed.

Kurennoy, Sergey S. [Los Alamos National Laboratory; Chan, Kwok-Chi Dominic [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Turchi, Peter J. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

427

Terahop and Lawrence Livermore National LaboratoryStructural Fire RF Testing  

SciTech Connect

The Georgia Public Safety Training Center's Live Fire Training Facility in Forsyth, GA is a three story structure constructed of rebar-reinforced concrete wall and floors. All the door and window coverings on the building are constructed of thick, plate metal to withstand the high temperatures generated inside the building during training exercises. All of the building's walls and floors are 1-foot thick, and regular concrete columns run up along the inside of the wall increasing the thickness to 20-inches in those locations. A center concrete staircase divides the structure in half. For typical exercises, fires are started in the back right corner of the building on the first floor and in the front right corner on the second floor as shown in Figure 2. Due to the high heat generated during these exercises, measured at 300 F on the floor and 700 F near the ceilings, there were limited locations at which equipment could be placed that did not incorporate heat shielding, such as the Lawrence Livermore National Laboratory's UWB system. However, upon inspection of the building, two preferable locations were identified in which equipment could be placed that would be protected from the temperature extremes generated by the fires. These locations are identified in Figure 2 as the tested TX locations. These were preferred locations because, while they protected the hardware from temperature extremes, they also force the RF transmission path through the building to cross very near the fire locations and anticipated plasma generation regions. Both of the locations listed in Figure 2 were tested by the UWB equipment and found to be suitable deployment locations to establish a solid RF link for data collection. The transmission location on the first floor was ultimately chosen for use during the actual exercises because it was accessible to the data collection team during the exercises. This allowed them to remove the hardware once the testing was complete without having to wait for the entire day of exercises to complete. Unfortunately, RF transmission directly through the central location of the fire on the first floor was not possible, so the transmission path had to be shifted approximately 6-feet off the side of the fire's center. The corner where the fire was located on the first floor was re-enforced with a mixture of concrete and metal fibers for heat resistance. This material was highly reflective, permitting very little RF energy to pass through it. This phenomenon was also observed and verified by Terahop's testing, discussed in the next section. An image of these re-enforced walls and a close up of the actual wall material containing the metal fibers can bee seen in Figure 3.

Haugen, P; Pratt, G

2007-02-26T23:59:59.000Z

428

RF/microwave non-destructive measurements of electrical properties of semiconductor wafers for thermophotovoltaic applications  

DOE Green Energy (OSTI)

A radio-frequency/microwave measurement system has been designed for non-contacting determination of sheet resistance and excess carrier lifetime of low-bandgap materials and junctions, specifically GaSb-based alloys for thermophotovoltaic (TPV) applications. The design incorporates RF circuitry in the 100--500 MHz frequency range and utilizes a Q-switched YAG laser at 1.32 microns to photo-generate electron-hole pairs and conductivity modulate the material and/or junction under test. Supplementary measurements with a GaAs pulsed diode laser at 904 nm provides a faster transient response with near-surface photogeneration. Initial measurements on GaSb substrates, Zn-diffused materials and epitaxially grown layers are presented and discussed.

Saroop, S.; Borrego, J.M.; Gutmann, R.J. [Rensselaer Polytechnic Inst., Troy, NY (United States)] [and others

1997-05-01T23:59:59.000Z

429

X-Band Active-Passive Rf Pulse Compressor with Plasma Switches  

SciTech Connect

As proposed by SLAC, the efficiency of a pulse compressor of the SLED-II type could be increased by changing both the phase of the microwave source and the coupling coefficient of the delay line. In the existing SLED-II system at frequency 11.4 GHz, the resonant delay line is coupled with the source via an iris with a constant reflection coefficient. Replacement of the iris with an active component makes it possible to create an active SLED-II system. In this paper, the use of plasma switches as the active elements is discussed. Plasma switches have been developed and tested at a high-power level for production of flattop compressed pulses. Active switching of SLED-II has demonstrated a marked increase in efficiency (by 20%) and power gain (by 37%) as compared with passive switching. The active compressor has produced 173 ns rf flattop output pulses with a power of about 112 MW.

Vikharev, A.L.; Ivanov, O.A.; Gorbachev, A.M.; /Nizhnii Novgorod, IAP /Omega-P, New Haven; Lobaev, M.A.; Isaev, V.A.; /Nizhnii Novgorod, IAP; Tantawi, S.G.; Lewandowski, J.R.; /SLAC; Hirshfield, J.L.; /Omega-P, New Haven /Yale U.

2012-04-27T23:59:59.000Z

430

Comparison Between Dust Particle Generation In CH4 or CH4/N2 Mixing RF Plasmas  

SciTech Connect

Dust particles have been spontaneously generated either in pure CH4 or in CH4/N2 r.f. plasmas. The dust particle formation results from homogeneous nucleation in the plasma and is detected by laser light scattering (Ar+, {lambda} = 514.5 nm). The temporal and spatial behaviour of dust particles is studied. In pure methane gas, particles are trapped in well defined clouds at the plasma sheath boundaries. In a CH4/N2 mixture, the nitrogen addition leads to an expansion of the clouds. For nitrogen contents higher than 50%, the space between the electrodes is nearly completely filled with dust particles leading to plasma instabilities and a void appears in the center of the discharge. The particles are spherical with diameters in the range 0.8-2 {mu}m. For nitrogen-rich plasmas, the particles growth is improved and leads to a rough shape with an orange-peel-type surface texture.

Pereira, Jeremy; Massereau-Guilbaud, Veronique; Geraud-Grenier, Isabelle; Plain, Andre [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G.Berger, BP 4043, 18028 Bourges Cedex (France)

2005-10-31T23:59:59.000Z

431

Focusing solenoid for the front end of a linear RF accelerator  

SciTech Connect

A prototype of a superconducting focusing solenoid for use in an RF linac has been built and tested at Fermi National Accelerator Laboratory (FNAL). The solenoid is comprised of the main coil, two bucking coils, two dipole corrector windings, and a low carbon steel flux return. At the excitation current of 250 A, the magnetic field reaches 7.2 T in the center of the solenoid and is less than 5 G on the axis at a distance of 150 mm from the center. The length of the solenoid is 150 mm; the length of a cryovessel for the solenoid with a 20 mm diameter 'warm' bore is 270 mm. This paper presents the main design features of the focusing solenoid and discusses results from tests of the solenoid.

Terechkine, I.; Kashikhin, V.V.; Page, T.; Tartaglia, M.; Tompkins, J.; /Fermilab

2007-06-01T23:59:59.000Z

432

Emittance Studies of the BNL/SLAC/UCLA 1.6 Cell Photocathode RF Gun  

SciTech Connect

The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 {mu}s. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, {epsilon}{sub o}, of the copper cathode has been measured.

Palmer, D.T.; /SLAC; Wang, X.J.; /Brookhaven; Miller, R.H.; /SLAC; Babzien, M.; Ben-Zvi, I.; /Brookhaven; Pellegrini, C.; /UCLA; Sheehan, J.; Skaritka, J.; /Brookhaven; Winick, H.; /SLAC; Woodle, M.; Yakimenko, V.; /Brookhaven

2011-09-09T23:59:59.000Z

433

Design of a mechanically actuated RF grounding system for the ITER ICRH antenna  

E-Print Network (OSTI)

In the ITER equatorial ports containing ICRH antennas, parasitic electrical resonances can be excited in the nominal 20 mm clearance gap between the port walls and the plug contained within it. RF calculations have established that these resonances can be effectively mitigated by a series of suitably located electrically conducting contacts between the port and plug. These contacts must allow installation and removal of the antenna but must also make reliable electrical contact during antenna operation. In addition, the contacts must be compliant enough to survive deflection of the port during seismic and disruption events without transmitting large forces to the vacuum vessel. The distance to be spanned is subject to significant uncertainty, due to the large manufacturing tolerances of the surrounding components, and this also must be considered during the design process. This paper outlines progress made in the design of the grounding system, as well as detailing a number of concepts which have been investi...

Hancock, D; Beaumont, B; Dumortier, P; Durodie, F; Kyrytsya, V; Louche, F; McKinley, R; Nicholls, K

2013-01-01T23:59:59.000Z

434

Diffusion Dynamics of Charged Dust Particles in Capacitively Coupled RF Discharge System  

SciTech Connect

Dusty plasma is loosely defined as electron-ion plasma with additional charged components of micron-sized dust particles. In this study, we developed a particle diagnostic technique based on light scattering and particle tracking velocimetry to investigate the dynamics of micron-sized titanium oxide particles in Argon gas capacitively coupled rf-discharge. The particle trajectories are constructed from sequence of image frames and treated as sample paths of charged Brownian motion. At specific sets of plasma parameters, disordered liquid-like dust particle configuration are observed. Mean-square-displacement of the particle trajectories are determined to characterize the transport dynamics. We showed that the dust particles in disordered liquid phase exhibit anomalous diffusion with different scaling exponents for short and large time scales, indicating the presence of slow and fast modes which can be related to caging effect and dispersive transport, respectively.

Chew, W. X.; Muniandy, S. V.; Wong, C. S.; Yap, S. L.; Tan, K. S. [Plasma Research Laboratory, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

435

High deposition rate preparation of amorphous silicon solar cells by rf glow discharge decomposition of disilane  

SciTech Connect

The optical and electrical properties of hydrogenated amorphous silicon films produced by rf glow discharge decomposition of disilane diluted in helium (Si/sub 2/H/sub 6//He = 1/9) have been studied while systematically varying the film deposition rate. The properties and composition of the films were monitored by measuring the optical band gap, IR vibrational spectrum, dark conductivity, and the photoconductivity as a function of the deposition rate. The photoluminescence of the high deposition rate films gave a peak at 1.33 eV. These films, whose properties are rather similar to those of the conventional a-Si:H films prepared from monosilane, have been used to fabricate nip-type a-Si:H solar cells. At a deposition rate of 11 A/sec, a conversion efficiency of 6.86% was obtained. This high efficiency shows that disilane is applicable for mass production fabrication of a-Si:H solar cells.

Kenne, J.; Ohashi, Y.; Matsushita, T.; Konagai, M.; Takahashi, K.

1984-01-15T23:59:59.000Z

436

300 MHz RF coils for MR studies of Macaca mulatta brain at 7 Tesla Hellmut Merkle2  

E-Print Network (OSTI)

300 MHz RF coils for MR studies of Macaca mulatta brain at 7 Tesla Hellmut Merkle2 , Josef Pfeuffer, customized for a vertical ultra high field 7 Tesla system develop for vision research in the alert, trained macaque. Methods A prototype primate chair was designed and built for the vertical 7-Tesla/60-cm BRUKER

437

IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 55, NO. 4, APRIL 2008 1067 Nonuniform RF Overstress in High-Power  

E-Print Network (OSTI)

voltage (VRF) across a loop, which is strongly affected by internal reflections in the device and mismatch effects. In some cases, nonuniformity in VRF occurs due to parasitic oscillations excited under actual). Digital Object Identifier 10.1109/TED.2008.916719 RF stress. Monitoring the spatial distribution of VRF

Shapira, Yoram

438

Efficient Broadband RF Energy Harvesting for Wireless Sensors Joseph A. Hagerty, Tian Zhao, Regan Zane and Zoya Popovic  

E-Print Network (OSTI)

energy coupling DC-DC converter that uses either inductive or capacitive elements for internal energy Electronics Cin Cload Cst Exfr Eop Energy Coupling DC-DC Converter Figure 2. Functional schematicEfficient Broadband RF Energy Harvesting for Wireless Sensors Joseph A. Hagerty, Tian Zhao, Regan

439

Charging effects in CdSe nanocrystals embedded in SiO2 matrix produced by rf magnetron sputtering  

Science Conference Proceedings (OSTI)

Charging effects in CdSe nanocrystals embedded in SiO"2 matrix fabricated by rf magnetron co-sputtering technique were electrically characterized by means of capacitance-voltage (C-V) combined with current-voltage (I-V). The presence of CdSe nanocrystals ... Keywords: CdSe, Charging effect, Nanocrystals, SiO2

S. Levichev; A. Chahboun; P. Basa; A. G. Rolo; N. P. Barradas; E. Alves; Zs. J. Horvath; O. Conde; M. J. M. Gomes

2008-12-01T23:59:59.000Z

440

On the electrical properties of slotted metallic planes in CMOS processes for RF and millimeter-wave applications  

Science Conference Proceedings (OSTI)

This paper presents a study of the effects of slotted metallic planes in passive structures built using CMOS processes for RF and millimeter-wave (mmW) applications. The impact of holes on the reference plane resistance and in the capacitance of any ... Keywords: CMOS manufacturing, Electromagnetic analysis, Interconnections, Metal density rules, Transmission lines, mmW integrated circuits

José Luis GonzáLez; Baudouin Martineau; Didier Belot

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "zr hf rf" from the National Library of EnergyBeta (NLEBeta).
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441

Rapid Relaxation and Embrittlement of Zr-based Bulk Metallic Glasses by Electropulsing  

Science Conference Proceedings (OSTI)

Mechanical relaxation and embrittlement of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glasses were achieved rapidly by the direct current electropulsing treatment. The temperature profile was recorded by an infrared camera and it was found to be non-uniform in the treated specimen. Specifically, temperatures below the glass transition temperature, near and above the crystallization temperature could be ach- ieved, respectively, at different locations in the same treated specimen. Two sets of nanoindentation were conducted. While the first set investigated the mechanical properties of three individually elec- tropulsed specimens with different conditions, the second set indented a single treated specimen along its temperature gradient. Both sets of indentation revealed that by Joule heating to different tempera- tures, relaxation, embrittlement, and crystallization were significantly accelerated by electrical pulses. Results suggest that electropulsing provides an opportunity to simultaneously achieve plastic forming and mechanical property control of metallic glasses.

Yiu, P [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan; Chen, Y. C. [National Taiwan University of Science & Technology; Chu, J. P. [National Taiwan Ocean University; Chang, S Y [National Chung Hsing University; Bei, Hongbin [ORNL; Jang, J. S.C. [National Central University, Jhongli 32001, Taiwan; Hsueh, C. H. [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan

2013-01-01T23:59:59.000Z

442

Measurement of the $^{90, 92}$Zr(p,$?$)$^{91,93}$Nb reactions for the nucleosynthesis of elements around A=90  

E-Print Network (OSTI)

Cross section measurements of the reactions $^{90, 92}$Zr(p,$\\gamma$)$^{91,93}$Nb were performed using the NSCL SuN detector at the University of Notre Dame. These reactions are part of the nuclear reaction flow for the synthesis of the light p nuclei. For the $^{90}$Zr(p,$\\gamma$)$^{91}$Nb reaction the new measurement resolves the disagreement between previous results. For the $^{92}$Zr(p,$\\gamma$)$^{93}$Nb reaction the present work reports the first measurement of this reaction cross section. Both reaction cross sections are compared to theoretical calculations and a very good agreement with the standard NON-SMOKER model is observed.

A. Spyrou; S. J. Quinn; A. Simon; T. Rauscher; A. Battaglia; A. Best; B. Bucher; M. Couder; P. A. DeYoung; A. C. Dombos; X. Fang; J. Gorres; A. Kontos; Q. Li; L. Y. Lin; A. Long; S. Lyons; B. S. Meyer; A. Roberts; D. Robertson; K. Smith; M. K. Smith; E. Stech; B. Stefanek; W. P. Tan; X. D. Tang; M. Wiescher

2013-10-21T23:59:59.000Z

443

Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR.  

SciTech Connect

We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays.

Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

2007-03-01T23:59:59.000Z

444

Evaluation of a RF-Based Approach for Tracking UF6 Cylinders at a Uranium Enrichment Plant  

SciTech Connect

Approved industry-standard cylinders are used globally to handle and store uranium hexafluoride (UF{sub 6}) feed, product, tails, and samples at uranium enrichment plants. The International Atomic Energy Agency (IAEA) relies on time-consuming physical inspections to verify operator declarations and detect possible diversion of UF{sub 6}. Development of a reliable, automated, and tamper-resistant system for near real-time tracking and monitoring UF{sub 6} cylinders (as they move within an enrichment facility) would greatly improve the inspector function. This type of system can reduce the risk of false or misreported cylinder tare weights, diversion of nuclear material, concealment of excess production, utilization of undeclared cylinders, and misrepresentation of the cylinders contents. This paper will describe a proof-of-concept approach that was designed to evaluate the feasibility of using radio frequency (RF)-based technologies to track individual UF{sub 6} cylinders throughout a portion of their life cycle, and thus demonstrate the potential for improved domestic accountability of materials, and a more effective and efficient method for application of site-level IAEA safeguards. The evaluation system incorporates RF-based identification devices (RFID) which provide a foundation for establishing a reliable, automated, and near real-time tracking system that can be set up to utilize site-specific, rules-based detection algorithms. This paper will report results from a proof-of-concept demonstration at a real enrichment facility that is specifically designed to evaluate both the feasibility of using RF to track cylinders and the durability of the RF equipment to survive the rigors of operational processing and handling. The paper also discusses methods for securely attaching RF devices and describes how the technology can effectively be layered with other safeguard systems and approaches to build a robust system for detecting cylinder diversion. Additionally, concepts for off-site tracking of cylinders are described.

Pickett, Chris A [ORNL; Younkin, James R [ORNL; Kovacic, Donald N [ORNL; Laughter, Mark D [ORNL; Hines, Jairus B [ORNL; Boyer, Brian [Los Alamos National Laboratory (LANL); Martinez, B. [Los Alamos National Laboratory (LANL)

2008-01-01T23:59:59.000Z

445

A comparison of crystalline and molten structures of zirconolite (CaZrTi?O?), a potential plutonium wasteform medium, by molecular dynamics simulation and topological analysis  

E-Print Network (OSTI)

Molecular dynamics simulations of the ceramic compound zirconolite (CaZrTi?O?), a potential crystalline wasteform host for plutonium, were carried out for ideal and experimental crystalline forms and a simulated molten ...

Rich, Sarah Celeste

2008-01-01T23:59:59.000Z

446

Rainfall Measurement Error by WSR-88D Radars due to Variations in Z–R Law Parameters and the Radar Constant  

Science Conference Proceedings (OSTI)

An investigation is made of the extent to which variations in Z–R (reflectivity factor–rainfall rate) relations can explain the systematically large offsets of radar-measured rainfall from rain gauge measurements as observed with some National ...

C. W. Ulbrich; L. G. Lee

1999-08-01T23:59:59.000Z

447

Gas Phase Chromatography of some Group 4, 5, and 6 Halides  

Science Conference Proceedings (OSTI)

Gas phase chromatography using The Heavy Element Volatility Instrument (HEVI) and the On Line Gas Apparatus (OLGA III) was used to determine volatilities of ZrBr{sub 4}, HfBr{sub 4}, RfBr{sub 4}, NbBr{sub 5}, TaOBr{sub 3}, HaCl{sub 5}, WBr{sub 6}, FrBr, and BiBr{sub 3}. Short-lived isotopes of Zr, Hf, Rf, Nb, Ta, Ha, W, and Bi were produced via compound nucleus reactions at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory and transported to the experimental apparatus using a He gas transport system. The isotopes were halogenated, separated from the other reaction products, and their volatilities determined by isothermal gas phase chromatography. Adsorption Enthalpy ({Delta}H{sub a}) values for these compounds were calculated using a Monte Carlo simulation program modeling the gas phase chromatography column. All bromides showed lower volatility than molecules of similar molecular structures formed as chlorides, but followed similar trends by central element. Tantalum was observed to form the oxybromide, analogous to the formation of the oxychloride under the same conditions. For the group 4 elements, the following order in volatility and {Delta}H{sub a} was observed: RfBr{sub 4} > ZrBr{sub 4} > HfBr{sub 4}. The {Delta}H{sub a} values determined for the group 4, 5, and 6 halides are in general agreement with other experimental data and theoretical predictions. Preliminary experiments were performed on Me-bromides. A new measurement of the half-life of {sup 261}Rf was performed. {sup 261}Rf was produced via the {sup 248}Cm({sup 18}O, 5n) reaction and observed with a half-life of 74{sub -6}{sup +7} seconds, in excellent agreement with the previous measurement of 78{sub -6}{sup +11} seconds. We recommend a new half-life of 75{+-}7 seconds for {sup 261}Rf based on these two measurements. Preliminary studies in transforming HEVI from an isothermal (constant temperature) gas phase chromatography instrument to a thermochromatographic (variable temperature) instrument have been completed. Thermochromatography is a technique that can be used to study the volatility and {Delta}H{sub a} of longer-lived isotopes off-line, Future work will include a comparison between the two techniques and the use of thermochromatography to study isotopes in a wider range of half-lives and molecular structures.

Sylwester, Eric Robert

1998-10-01T23:59:59.000Z

448

REACTIVE FORCE FIELDS FOR Y-DOPED BaZrO3 ELECTROLYTE AND NI-ANODE. POTENTIAL CATHODE MATERIALS FOR APPLICATION IN PROTON CERAMIC FUEL CELLS  

DOE Green Energy (OSTI)

Based on quantum mechanical data obtained for the Y-doped BaZrO{sub 3} electrolyte and Ni-anode Reactive Force Field parameters have been developed for further molecular dynamics simulations of the proton diffusion and electrode/electrolyte interfaces. Electronic and atomic structures of different terminations of the (001) BaZrO{sub 3} surface have been studied using first-principles calculations. Several potential cathode materials for the Y-doped BaZrO{sub 3} system were synthesized via glycine nitrate combustion method. Of the five potential cathode materials examined BaZr{sub 0.40}Pr{sub 0.40}Gd{sub 0.20}O{sub 3} and BaZr{sub 0.60}Y{sub 0.20}Co{sub 0.20}O{sub 3} appear to be the most promising for further applications in proton ceramic fuel cells. Fuel cell test of a Y-doped BaZrO{sub 3} thin film using platinum ink for both electrodes have been performed. The obtained results shows that a robust method for fabricating crack-free thin membranes, as well as methods for sealing anode and cathode chambers, have successfully been developed.

Boris Merinov; Adri van Duin; Sossina Haile; William A. Goddard III

2004-10-30T23:59:59.000Z

449

Proton nuclear magnetic resonance studies of hydrogen diffusion and electron tunneling in Ni-Nb-Zr-H glassy alloys  

Science Conference Proceedings (OSTI)

Using the Fourier transform of the echo envelope, the proton line shapes, spin-lattice relaxation time, and spin-spin relaxation time have been measured in a (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy at 1.83 T ({approx}78 MHz) and at temperatures between 1.8 and 300 K. First, the spectral line width decreases abruptly between 1.8 and 2.1 K. Next, it remains almost constant at 13 kHz up to {approx}150 K. Finally, the line width decreases as the temperature increases from {approx}150 to 300 K. The initial decrease in the spectral line width is ascribed to the distribution of the external field, which is caused by the penetration of vortices in the superconducting state. The subsequent leveling off in the spectral line width is ascribed to the dipole-dipole interaction between protons when hydrogen atoms are trapped into vacancies among the Zr-centered icosahedral Zr{sub 5}Ni{sub 5}Nb{sub 3} clusters. The final decrease in the spectral line width is ascribed to the motional narrowing of the width that is caused by the movement of hydrogen atoms. The temperature dependences of the spin-lattice and spin-spin relaxation time showed that at temperature above 150 K and the activation energy of 8.7 kJ/mol allowed the hydrogen atoms to migrate among the clusters. The distance between the hydrogen atoms is estimated to be 2.75 A. Hydrogen occupancies among clusters in the (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy play an important role in the diffusion behavior and in the electronic properties of this alloy.

Niki, Haruo; Okuda, Hiroyuki; Oshiro, Morihito; Yogi, Mamoru [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Seki, Ichiro; Fukuhara, Mikio [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2012-06-15T23:59:59.000Z

450

The Effect of Zn Addition on the Oxidation State of Cobalt in Co/ZrO2 Catalysts  

Science Conference Proceedings (OSTI)

The effect of Zn promotion on the activity and selectivity of Co/ZrO{sub 2} catalysts for ethanol steam reforming was investigated. The catalysts were synthesized by incipient wetness impregnation and characterized using BET measurements, temperature programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray electron spectroscopy. Compared to Co/ZrO{sub 2} catalyst, a higher ethanol conversion and a lower CH{sub 4} selectivity were observed for the Co/ZrO{sub 2} catalyst promoted with Zn. It was found that addition of Zn inhibits the oxidation of metallic cobalt (Co{sup 0}) particles, which results in a higher ratio of Co{sup 0}/Co{sup 2+} present in the Zn promoted Co/ZrO{sub 2} catalyst. These results suggest that metallic cobalt (Co{sup 0}) is responsible for ethanol conversion via ethanol dehydrogenation whereas Co{sup 2+} plays a role in the CH{sub 4} formation. For both catalysts, the experimental results show that CH4 is mainly produced via CO and/or CO{sub 2} methanation. TPR measurements, on the other hand, show Zn addition inhibits the reduction of Co{sup 2+} and Co{sup 3+}, which would mislead the conclusion that oxidized Co is required to reduce the CH{sub 4} formation. Therefore, TPR may not be appropriate to correlate the degree of metal reducibility (in this case Co{sup 0}) with the catalyst activity for reactions such as ethanol steam reforming where oxidizing conditions exist.

Lebarbier, Vanessa MC; Karim, Ayman M.; Engelhard, Mark H.; Wu, Yu; Xu, Bo-Qing; Petersen, Eric J.; Datye, Abhaya K.; Wang, Yong

2011-09-01T23:59:59.000Z

451

FMC·RF'2a U.S. DEPARTlVIENT OF ENERGY EERE PROJECT MANAGEMENT CENTER  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

FMC·RF'2a FMC·RF'2a U.S. DEPARTlVIENT OF ENERGY EERE PROJECT MANAGEMENT CENTER NEPA DETERlVIINATION RECIPIENT:Nevada State Office of Energy STATE: NV PROJECT Renewable Energy and Energy Efficiency Revolving Loan Program - Enigma Energy TITLE: Funding Opportunity Announcement Number Procurement Instrument Number NEPA Control Number CID Number DE-FOA-OOOOOS2 DE-EE-0000084 GFO-0000084-012 EE84 Based on my review of the information concerning the proposed action, as NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: CX, EA, EIS APPENDIX AND NUMBER: Description: 85.1 Actions to conserve energy, demonstrate potential energy conservation , and promote energy-efficiency that do not increase the indoor concentrations of potentially harmful substances

452

Conceptual Design for Replacement of the DTL and CCL with Superconducting RF Cavities in the Spallation Neutron Source Linac  

Science Conference Proceedings (OSTI)

The Spallation Neutron Source Linac utilizes normal conducting RF cavities in the low energy section from 2.5 MeV to 186 MeV. Six Drift Tube Linac (DTL) structures accelerate the beam to 87 MeV, and four Coupled Cavity Linac (CCL) structures provide further acceleration to 186 MeV. The remainder of the Linac is comprised of 81 superconducting cavities packaged in 23 cryomodules to provide final beam energy of approximately 1 GeV. The superconducting Linac has proven to be substantially more reliable than the normal conducting Linac despite the greater number of stations and the complexity associated with the cryogenic plant and distribution. A conceptual design has been initiated on a replacement of the DTL and CCL with superconducting RF cavities. The motivation, constraints, and conceptual design are presented.

Champion, Mark S [ORNL; Doleans, Marc [ORNL; Kim, Sang-Ho [ORNL

2013-01-01T23:59:59.000Z

453

Negative effect of crystallization on the mechanism of laser damage in a HfO{sub 2}/SiO{sub 2} multilayer  

Science Conference Proceedings (OSTI)

Elucidation of the mechanisms of laser damage is indispensable in realizing high resistance mirrors for the next generation of ultra-short pulse high intensity lasers. In this study, the surface and a section of the laser-damaged area of a laser mirror were observed with a laser microscope and a transmission electron microscope (cross-sectional TEM), respectively. A grain boundary of HfO{sub 2} microcrystal was observed in the damaged area. This observation and an evaluation of the mirror's damage resistance showed that the formation of crystals in the multilayer mirror is one of the major determinants of damage resistance.

Tateno, Ryo [Shimadzu Corporation, 1, Nishinokyo-Kuwabaracho Nakagyo-ku, Kyoto 604-8511 (Japan); Okada, Hajime; Otobe, Tomohito; Kawase, Keigo; Koga, James K.; Kosuge, Atsushi; Nagashima, Keisuke; Sugiyama, Akira [Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215 (Japan); Kashiwagi, Kunihiro [Department of Electrical and Communication Engineering, Faculty of Engineering, Toyo University, 2100, Kujirai Kawagoe-shi, Saitama 350-8585 (Japan)

2012-12-15T23:59:59.000Z

454

Stray RF Power Estimates From EC Exploitation During ITER Plasma Operations  

SciTech Connect

The EC H and CD system of ITER tokamak is an essential tool for all the phases of ITER operation. Different levels of EC power are required through all the plasma discharge: up to 6.7 MW for assisting the breakdown and burn through, up to 20 MW for current drive and saw-teeth control from the equatorial launcher and up to 20 MW for NTM stabilization from the upper launchers. The assistance to breakdown and burn through is characterized by a very low (if not negligible) RF power absorption by the plasma. A significant level of stray radiation may also arise from partial absorption due to non-optimal plasma parameters and/or wrong injected polarization. The stray power radiated in the vacuum chamber is estimated as a first step toward mitigating potential harmful consequence to in-vessel structures and diagnostics. Power loading of the chamber walls (peek power and average power density for straight beam propagation in the empty chamber) and diffuse stray radiation effects are simulated to infer suitable strategies to avoid damage to first wall and to microwave sensitive components.

Gandini, F.; Henderson, M.; Darbos, C.; Gassmann, T.; Purohit, D.; Omori, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Nazare, C. [Assystem Facilities, 78067 Saint Quentin en Yvelines Cedex (France)

2011-12-23T23:59:59.000Z

455

Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities  

SciTech Connect

In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

Bane, K.L.F.; Adolphsen, C.; Li, Z.; /SLAC; Dohlus, M.; Zagorodnov, I.; /DESY; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; /Fermilab; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

2008-07-07T23:59:59.000Z

456

Growth of TiO{sub 2} Thin Film on Various Substrates using RF Magnetron Sputtering  

Science Conference Proceedings (OSTI)

The conductivity of Titanium Dioxide (TiO{sub 2}) thin film fabricated using Radio Frequency (RF) Magnetron Sputtering on Silicon (Si), Indium doped--Tin Oxide (ITO) and microscope glass (M) substrates is presented in this paper. The dependant of thin film thickness and type of substrate been discussed. TiO{sub 2} was deposited using Ti target in Ar+O{sub 2}(45:10) mixture at 250 W for 45, 60, 75, 90, 105 and 120 minute. Resultant thickness varies from 295 nm to 724 nm with deposition rate 6.4 nm/min. On the other hand, resistivity, Rs value for ITO substrate is between 5.72x10{sup -7} to 1.54x10{sup -6{Omega}}.m, Si substrate range is between 3.52x10{sup -6} to 1.76x10{sup -5{Omega}}.m and M substrate range is between 99 to 332 {Omega}.m. The value of resistivity increases with the thickness of the thin film.

Ali, Riyaz Ahmad Mohamed; Nayan, Nafarizal [Microelectronic and Nanotechnology-Shamsuddin Research Center (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Batu Pahat, Johor D.T. (Malaysia)

2011-03-30T23:59:59.000Z

457

Design of compact frequency synthesizer for self-calibration in RF circuits  

E-Print Network (OSTI)

A compact frequency synthesizer based on a phase locked loop (PLL) is designed for the self-calibration in RF circuits. The main advantage of the presented frequency synthesizer is that it can be built in a small silicon area using MOSFET interface trap charge pump (ITCP) current generators. The ITCP current generator makes it possible to use small currents at nano-ampere levels so that small capacitances can be used in the loop filter. A large resistance, which is required to compensate for the reduced capacitances, is implemented using an operational transconductance amplifier (OTA). An ITCP current generator is used as a tail current source for the OTA in order to realize a small transconductance. The presented frequency synthesizer has the output frequency range from 570 MHz to 600 MHz with a 100 KHz frequency step. Total silicon area is about 0.3 mm2 using AMIS 0.5 ??m CMOS technology, and the power consumption is 26.7 mW with 3 V single power supply.

Park, Sanghoon

2004-08-01T23:59:59.000Z

458

Implementation of longitudinal dynamics with barrier RF in BETACOOL and comparison to ESME  

Science Conference Proceedings (OSTI)

The barrier bucket RF system is successfully used on Recycler storage ring at Fermilab. The special program code ESME was used for numerical simulation of longitudinal phase space manipulations. This program helps optimizing the various regimes of operation in the Recycler and increasing the luminosity in the colliding experiments. Electron and stochastic cooling increases the phase space density in all degrees of freedom. In the case of a small phase space volume the intrabeam scattering introduces coupling between the transverse and longitudinal temperatures of the antiproton beam. For numerical simulations of the cooling processes at the Recycler, a new model of the barrier buckets was implemented in the BETACOOL code. The comparison between ESME and BETACOOL codes for a stationary and moving barrier buckets is presented. This article also includes an application of the barrier bucket numerical model for simulation of the luminosity distribution for RHIC colliding experiments. These simulations take into account the specific longitudinal distribution of the bunch and the vertex size of the detector.

Smirnov, A.; Fedotov, A.; Sidorin, A.; Krestnikov, D.; Bhat, C.; Prost, L.

2009-08-31T23:59:59.000Z