Sample records for high-power coherent terahertz

  1. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a...

  2. From high power terahertz quantum cascade lasers to terahertz light amplifiers

    E-Print Network [OSTI]

    Kao, Tsung-Yu

    2014-01-01T23:59:59.000Z

    The terahertz (THz) frequency range (300 GHz to 10 THz, wavelength 30-1000 [mu]m), despite having many potential applications, is technologically relatively underdeveloped mainly because of the lack of suitable coherent ...

  3. High power terahertz generation using 1550?nm plasmonic photomixers

    SciTech Connect (OSTI)

    Berry, Christopher W. [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hashemi, Mohammad R.; Jarrahi, Mona [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Electrical Engineering Department, University of California Los Angeles, Los Angeles, California 90095 (United States); Preu, Sascha [Department of Electrical Engineering and Information Technology, Technical University Darmstadt, D-64283 Darmstadt (Germany); Lu, Hong; Gossard, Arthur C. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2014-07-07T23:59:59.000Z

    We present a 1550?nm plasmonic photomixer operating under pumping duty cycles below 10%, which offers significantly higher terahertz radiation power levels compared to previously demonstrated photomixers. The record-high terahertz radiation powers are enabled by enhancing the device quantum efficiency through use of plasmonic contact electrodes, and by mitigating thermal breakdown at high optical pump power levels through use of a low duty cycle optical pump. The repetition rate of the optical pump can be specifically selected at a given pump duty cycle to control the spectral linewidth of the generated terahertz radiation. At an average optical pump power of 150 mW with a pump modulation frequency of 1 MHz and pump duty cycle of 2%, we demonstrate up to 0.8 mW radiation power at 1 THz, within each continuous wave radiation cycle.

  4. High-power terahertz optically pumped NH{sub 3} laser for plasma diagnostics

    SciTech Connect (OSTI)

    Mishchenko, V. A.; Petrushevich, Yu. V.; Sobolenko, D. N.; Starostin, A. N. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

    2012-06-15T23:59:59.000Z

    The parameter of a terahertz (THz) laser intended for plasma diagnostics in electrodynamic accelerators and tokamaks with a strong magnetic field are discussed. Generation of THz radiation in an ammonia laser under the action of high-power pulsed optical pumping by the radiation of a 10P(32) CO{sub 2} laser is simulated numerically. The main characteristics of the output radiation, such as its spectrum, peak intensity, time dependence, and total energy, are calculated.

  5. CIRCE: A dedicated storage ring for coherent THz synchrotron radiation

    E-Print Network [OSTI]

    2003-01-01T23:59:59.000Z

    High-power terahertz radiation from relativistic electrons",coherent THz synchrotron radiation: Measuring the Josephsonof coherent synchrotron radiation from the NSLS VUV ring",

  6. Generation of high power pulsed terahertz radiation using a plasmonic photoconductive emitter array with logarithmic spiral antennas

    SciTech Connect (OSTI)

    Berry, Christopher W. [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hashemi, Mohammad R.; Jarrahi, Mona [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)

    2014-02-24T23:59:59.000Z

    An array of 3?×?3 plasmonic photoconductive terahertz emitters with logarithmic spiral antennas is fabricated on a low temperature (LT) grown GaAs substrate and characterized in response to a 200 fs optical pump from a Ti:sapphire mode-locked laser at 800?nm wavelength. A microlens array is used to split and focus the optical pump beam onto the active area of each plasmonic photoconductive emitter element. Pulsed terahertz radiation with record high power levels up to 1.9 mW in the 0.1–2 THz frequency range is measured at an optical pump power of 320 mW. The record high power pulsed terahertz radiation is enabled by the use of plasmonic contact electrodes, enhancing the photoconductor quantum efficiencies, and by increasing the overall device active area, mitigating the carrier screening effect and thermal breakdown at high optical pump power levels.

  7. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home asLCLSLaboratoryRowlandRevolutionizing

  8. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home asLCLSLaboratoryRowlandRevolutionizingLaser Seeding

  9. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaserLaser Seeding Yields

  10. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaserLaser Seeding YieldsLaser

  11. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaserLaser Seeding YieldsLaserLaser

  12. Laser Seeding Yields High-Power Coherent Terahertz Radiation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaserLaser Seeding

  13. Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    of coherent transition radiation generated at a plasma-and G. Fubiani, “Terahertz radiation from laser acceleratedW. P. Leemans, “Synchrotron radiation from electron beams in

  14. Plasma physics and related challenges of millimeter-wave-to-terahertz and high power microwave generationa...

    E-Print Network [OSTI]

    Smith, James E.

    confronting "classic" high power microwave HPM generators including long-life bright electron beam sources, high power mmw-to-THz sources are compared and contrasted to those of HPM generation, and future assume long pulse or average power, with exceptions be- tween 1 and 10 GHz for high power microwave HPM

  15. Generation of high-power tunable terahertz-radiation by nonrelativistic beam-echo harmonic effect

    SciTech Connect (OSTI)

    Gong Huarong; Xu Jin; Wei Yanyu; Gong Yubin [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Travish, Gil [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Feng Jinjun [Vacuum Electronics National Laboratory, Vacuum Electronics research Institute, Beijing 100016 (China)

    2013-01-15T23:59:59.000Z

    A new type of terahertz radiation source based on the nonrelativistic electron beam-wave interaction is proposed. Here, the beam echo harmonic effect is applied to a traveling wave tube like device. The scheme is configured as a combination of a frequency multiplier and amplifier with, for instance, W-band (millimeter wave) input signals and terahertz output power. A one-dimensional model of this device shows that a 10th order harmonic-wave can be generated while other harmonic waves are suppressed. The device only requires a readily available input source (W-band), and the output frequency can be tuned continuously over a wide band.

  16. Terahertz quantum cascade laser based optical coherence tomography

    E-Print Network [OSTI]

    Lee, Alan W. M.

    The interfaces of a dielectric sample are resolved in reflection geometry using light from a frequency agile array of terahertz quantum-cascade lasers. The terahertz source is a 10-element linear array of third-order ...

  17. Folie 1 > DESY, 14.11.2006 Analysis of coherent terahertz synchrotron radiation with a

    E-Print Network [OSTI]

    Folie 1 > DESY, 14.11.2006 Analysis of coherent terahertz synchrotron radiation Planetenforschung Rutherfordstr. 2, 12489 Berlin #12;Folie 2 > DESY, 14.11.2006 Outline Coherent synchrotron Outlook #12;Folie 3 > DESY, 14.11.2006 BESSY II reference orbit: L = 240 m L bunch Revolution: 1.25 MHz, 0

  18. Generation of high power sub-terahertz radiation from a gyrotron with second harmonic oscillation

    SciTech Connect (OSTI)

    Saito, Teruo; Yamada, Naoki; Ikeuti, Shinji; Tatematsu, Yoshinori; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka [Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Ogasawara, Shinya [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8463 (Japan); Manuilov, Vladimir N. [Nizhny Novgorod State University, Nizhny Novgorod 603600 (Russian Federation); Shimozuma, Takashi; Kubo, Shin; Nishiura, Masaki; Tanaka, Kenji; Kawahata, Kazuo [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2012-06-15T23:59:59.000Z

    New power records of second harmonic gyrotron oscillation have been demonstrated in the sub-THz band. The first step gyrotron of demountable type had succeeded in oscillation with power more than 50 kW at 350 GHz and nearly 40 kW at 390 GHz [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009)]. Then, the second step gyrotron of sealed-off type was manufactured. A cavity mode was carefully selected to avoid mode competition with a neighboring fundamental harmonic mode. Matching of the selected mode with the electron gun was also circumspectly considered. The second step gyrotron has attained higher power radiation than the first gyrotron. The maximum single mode power was 62 kW at 388 GHz. Then, the electron gun was modified for use of a different cavity mode with a higher coupling coefficient than that for the 62 kW mode. The new mode proved single mode oscillation power of 83 kW at about 389 GHz. These results are new second-harmonic-oscillation power records for sub-THz gyrotrons. The present study constitutes foundations of development of high power second harmonic sub-THz gyrotron for application to collective Thomson scattering measurement on fusion plasmas, especially on high-density plasmas such as those produced in LHD [N. Ohyabu et al., Phys. Rev. Lett. 97, 055002 (2006)]. This paper reports the design consideration to realize high power single mode gyrotron oscillation at second harmonic and the examination of oscillation characteristics of the gyrotron.

  19. Coherent Terahertz Polarization Control through Manipulation of Electron Trajectories Haidan Wen1

    E-Print Network [OSTI]

    Coherent Terahertz Polarization Control through Manipulation of Electron Trajectories Haidan Wen1 for manipulating and controlling the electron dy- namics associated with nonlinear light-matter interactions) The dynamics of ionized electrons in a plasma can be controlled by synthetic optical fields composed

  20. Second user workshop on high-power lasers at the Linac Coherent Light Source

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

    Heimann, Phil; Glenzer, Siegfried

    2015-05-04T23:59:59.000Z

    The second international workshop on the physics enabled by the unique combination of high-power lasers with the world-class Linac Coherent Light Source (LCLS) free-electron X-ray laser beam was held in Stanford, CA, on October 7–8, 2014. The workshop was co-organized by UC Berkeley, Lawrence Berkeley, Lawrence Livermore, and SLAC National Accelerator Laboratories. More than 120 scientists, including 40 students and postdoctoral scientists who are working in high-intensity laser-matter interactions, fusion research, and dynamic high-pressure science came together from North America, Europe, and Asia. The focus of the second workshop was on scientific highlights and the lessons learned from 16 newmore »experiments that were performed on the Matter in Extreme Conditions (MEC) instrument since the first workshop was held one year ago.« less

  1. Intense terahertz pulses from SLAC electron beams using coherent transition radiation

    SciTech Connect (OSTI)

    Wu Ziran; Fisher, Alan S.; Hogan, Mark; Loos, Henrik [Accelerator Directorate, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias [Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); Lindenberg, Aaron [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2013-02-15T23:59:59.000Z

    SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond electron bunches. These characteristics are ideal for generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration is typically 20 and 80 fs RMS and can be tuned via the electron bunch duration; emission spectra span 3-30 THz and 0.5 THz-5 THz; and the energy in a quasi-half-cycle THz pulse is 0.2 and 0.6 mJ. The peak electric field at a THz focus has reached 4.4 GV/m (0.44 V/A) at LCLS. This paper presents measurements of the terahertz pulses and preliminary observations of nonlinear materials response.

  2. Coherence and Linewidth Studies of a 4-nm High Power FEL

    E-Print Network [OSTI]

    Fawley, W.M.

    2008-01-01T23:59:59.000Z

    bandwidth for a single-pass FEL amplifier initiated by SASE.Studies of a 4-nm High Power FEL W.M. Fawley, A.M. Sessler,Studies of a 4-nm High Power FEL W. M. Fawley and A. M.

  3. Single-cycle terahertz pulses with >0.2 V/A field amplitudes via coherent transition radiation

    SciTech Connect (OSTI)

    Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias; Ghimire, Shambhu [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wen, Haidan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Reis, David A. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Loos, Henrik; Fisher, Alan S. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Lindenberg, Aaron M. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2011-10-03T23:59:59.000Z

    We demonstrate terahertz pulses with field amplitudes exceeding 0.2 V/A generated by coherent transition radiation. Femtosecond, relativistic electron bunches generated at the Linac Coherent Light Source are passed through a beryllium foil, and the emitted radiation is characterized as a function of the bunch duration and charge. Broadband pulses centered at a frequency of 10 THz with energies of 140 {mu}J are measured. These far-below-bandgap pulses drive a nonlinear optical response in a silicon photodiode, with which we perform nonlinear autocorrelations that yield information regarding the terahertz temporal profile. Simulations of the spatiotemporal profile agree well with experimental results.

  4. Terahertz field enhancement via coherent superposition of the pulse sequences after a single optical-rectification crystal

    SciTech Connect (OSTI)

    Sajadi, Mohsen, E-mail: sajadi@fhi-berlin.mpg.de; Wolf, Martin; Kampfrath, Tobias [Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

    2014-03-03T23:59:59.000Z

    Terahertz electromagnetic pulses are frequently generated by optical rectification of femtosecond laser pulses. In many cases, the efficiency of this process is known to saturate with increasing intensity of the generation beam because of two-photon absorption. Here, we demonstrate two routes to reduce this effect in ZnTe(110) crystals and enhance efficiency, namely, by (i) recycling the generation pulses and by (ii) splitting each generation pulse into two pulses before pumping the crystal. In both methods, the second pulse arrives ?1?ns after the first one, sufficiently long for optically generated carriers to relax. Enhancement is achieved by coherently superimposing the two resulting terahertz fields.

  5. Quantifying pharmaceutical film coating with optical coherence tomography and terahertz pulsed imaging: an evaluation

    E-Print Network [OSTI]

    Lin, Hungyen; Dong, Yue; Shen, Yaochun; Zeitler, J. Axel

    2015-06-11T23:59:59.000Z

    thickness within the thickness tolerance. However, when the leap between neighbouring peaks becomes too large leading to diverging coating thickness, the algorithm backtracks to a previously identified peak with a thickness value that is closest... -release tablet film coating. Eur J Pharm Biopharm 71(1):117-123. 18. Shen YC, Taday PF 2008. Development and Application of Terahertz Pulsed Imaging for Nondestructive Inspection of Pharmaceutical Tablet. Selected Topics in Quantum Electronics, IEEE...

  6. Terahertz quantum cascade lasers

    E-Print Network [OSTI]

    Williams, Benjamin S. (Benjamin Stanford), 1974-

    2003-01-01T23:59:59.000Z

    The development of the terahertz frequency range has long been impeded by the relative dearth of compact, coherent radiation sources of reasonable power. This thesis details the development of quantum cascade lasers (QCLs) ...

  7. REVIEW OF SCIENTIFIC INSTRUMENTS 84, 022701 (2013) Intense terahertz pulses from SLAC electron beams using coherent

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    February 2013) SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration field at a THz focus has reached 4.4 GV/m (0.44 V/Å) at LCLS. This paper presents measurements

  8. Room temperature broadband coherent terahertz emission induced by dynamical photon drag in graphene

    E-Print Network [OSTI]

    Maysonnave, J; Wang, F; Maero, S; Berger, C; de Heer, W; Norris, T B; De Vaulchier, L A; Dhillon, S; Tignon, J; Ferreira, R; Mangeney, J

    2015-01-01T23:59:59.000Z

    Nonlinear couplings between photons and electrons in new materials give rise to a wealth of interesting nonlinear phenomena. This includes frequency mixing, optical rectification or nonlinear current generation, which are of particular interest for generating radiation in spectral regions that are difficult to access, such as the terahertz gap. Owing to its specific linear dispersion and high electron mobility at room temperature, graphene is particularly attractive for realizing strong nonlinear effects. However, since graphene is a centrosymmetric material, second-order nonlinearities a priori cancel, which imposes to rely on less attractive third-order nonlinearities. It was nevertheless recently demonstrated that dc-second-order nonlinear currents as well as ultrafast ac-currents can be generated in graphene under optical excitation. The asymmetry is introduced by the excitation at oblique incidence, resulting in the transfer of photon momentum to the electron system, known as the photon drag effect. Here...

  9. Terahertz metamaterials

    DOE Patents [OSTI]

    Peralta, Xomalin Guaiuli; Brener, Igal; O'Hara, John; Azad, Abul; Smirnova, Evgenya; Williams, John D.; Averitt, Richard D.

    2014-08-12T23:59:59.000Z

    Terahertz metamaterials comprise a periodic array of resonator elements disposed on a dielectric substrate or thin membrane, wherein the resonator elements have a structure that provides a tunable magnetic permeability or a tunable electric permittivity for incident electromagnetic radiation at a frequency greater than about 100 GHz and the periodic array has a lattice constant that is smaller than the wavelength of the incident electromagnetic radiation. Microfabricated metamaterials exhibit lower losses and can be assembled into three-dimensional structures that enable full coupling of incident electromagnetic terahertz radiation in two or three orthogonal directions. Furthermore, polarization sensitive and insensitive metamaterials at terahertz frequencies can enable new devices and applications.

  10. High Power Cryogenic Targets

    SciTech Connect (OSTI)

    Gregory Smith

    2011-08-01T23:59:59.000Z

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  11. High power microwave generator

    DOE Patents [OSTI]

    Ekdahl, C.A.

    1983-12-29T23:59:59.000Z

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  12. Developments in time-resolved ultrafast imaging and spectroscopy at terahertz frequencies

    E-Print Network [OSTI]

    Teo, Stephanie M

    2014-01-01T23:59:59.000Z

    Prior to the advent of high energy pulsed femtosecond lasers, the field of terahertz (THz) spectroscopy was stagnated by the lack of both high power THz sources and sensitive THz detectors. Over the past few years, it has ...

  13. Numerical study on a 0.4 THz second harmonic gyrotron with high power

    SciTech Connect (OSTI)

    Chaojun, Lei [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China) [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); The Chinese People's Armed Police Force Academy, Langfang 065000 (China); Sheng, Yu; Hongfu, Li; Yinghui, Liu; Xinjian, Niu; Qixiang, Zhao [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China)] [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China)

    2013-07-15T23:59:59.000Z

    Terahertz and sub-terahertz science and technology are promising topics today. However, it is difficult to obtain high power source of terahertz wave. In this paper, the mode competition and beam-wave interaction in a gradually tapered cavity are studied to achieve high efficiency of a 0.4THz second harmonic gyrotron in practice. In order to attain high power and stable radiation, the TE{sub 32,5} mode is selected as the operating mode of the desired gyrotron to realize single mode oscillation. The issues of studying on the high-order mode gyrotrons are solved effectively by transforming the generalized telegraphist's equations. The efficiency and output power of the gyrotron under different conditions have been calculated by the code, which is based on the transformed equations. Consequently, the results show that single mode second harmonic radiation with power of over 150 kW at frequency of 0.4 THz could be achieved.

  14. High power connection system

    DOE Patents [OSTI]

    Schaefer, Christopher E. (Warren, OH); Beer, Robert C. (Noblesville, IN); McCall, Mark D. (Youngstown, OH)

    2000-01-01T23:59:59.000Z

    A high power connection system adapted for automotive environments which provides environmental and EMI shielding includes a female connector, a male connector, and a panel mount. The female connector includes a female connector base and a snap fitted female connector cover. The male connector includes a male connector base and a snap fitted male connector cover. The female connector base has at least one female power terminal cavity for seatably receiving a respective female power terminal. The male connector base has at least one male power terminal cavity for seatably receiving a respective male power terminal. The female connector is covered by a cover seal and a conductive shroud. A pair of lock arms protrude outward from the front end of the male connector base, pass through the panel mount and interface with a lever of a lever rotatably connected to the shroud to thereby mechanically assist mating of the male and female connectors. Safety terminals in the male and female connectors provide a last-to-connect-first-to-break connection with an HVIL circuit.

  15. Terahertz transmission of a Ba{sub 1{minus}{ital x}}K{sub {ital x}}BiO{sub 3} film probed by coherent time-domain spectroscopy

    SciTech Connect (OSTI)

    Gao, F.; Whitaker, J.F.; Liu, Y.; Uher, C. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Platt, C.E.; Klein, M.V. [Science and Technology Center for Superconductivity, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)] [Science and Technology Center for Superconductivity, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    1995-08-01T23:59:59.000Z

    The complex transmission coefficient for millimeter and submillimeter waves incident on a Ba{sub 0.6}K{sub 0.4}BiO{sub 3} thin film (82 nm) has been measured over a frequency range of 200--1200 GHz at temperatures above and below {ital T}{sub {ital c}} using coherent time-domain spectroscopy. We observe a dramatic change in both the magnitude and phase of the terahertz transmission in the superconducting state caused by a rapid carrier condensation. Both the real ({sigma}{sub 1}) and imaginary ({sigma}{sub 2}) parts of the complex conductivity are determined directly from the amplitude and phase of the transmitted electric field without the need for a Kramers-Kroenig analysis. By fitting {sigma}{sub 2} in the framework of BCS theory, a superconducting gap 2{Delta}(0)=6.9 meV=3.8{ital k}{sub {ital B}}{ital T}{sub {ital c}} is obtained. Below {ital T}{sub {ital c}}, the {sigma}{sub 1} is rapidly enhanced for {omega}/2{pi}{lt}500 GHz, which is attributed to the BCS coherence effects. However, the conductivity exhibits monotonic temperature dependence and no clear {sigma}{sub 1}({ital T}) peak is observed throughout the frequency range measured. The high-frequency penetration depth ({similar_to}600 nm) is also extracted and discussed. Our results are consistent with a picture of BCS moderate coupling superconductivity in an intermediate to dirty limit.

  16. Terahertz radiation by optical rectification in a hydrogen-bonded organic molecular ferroelectric crystal, 2-phenylmalondialdehyde

    E-Print Network [OSTI]

    Guan, W; Sotome, M; Kinoshita, Y; Takeda, R; Inoue, A; Horiuchi, S; Okamoto, H

    2014-01-01T23:59:59.000Z

    Terahertz radiation by optical rectification has been observed at room temperature in a hydrogen-bonded organic molecular ferroelectric crystal, 2-phenyl malondialdehyde (PhMDA). The radiated electromagnetic wave consisted of a single-cycle terahertz pulse with a temporal width of $\\sim$ 0.5 ps. The terahertz radiation amplitude divided by the sample thickness in PhMDA was nearly equivalent to that in a typical terahertz wave emitter ZnTe. This is attributable to a long coherence length in the range of 130 $\\sim$ 800 $\\mu$m for the terahertz radiation from PhMDA. We also discussed the possibility of PhMDA as a terahertz wave emitter in terms of the phase-matching condition.

  17. Integrated heterodyne terahertz transceiver

    DOE Patents [OSTI]

    Lee, Mark (Albuquerque, NM); Wanke, Michael C. (Albuquerque, NM)

    2009-06-23T23:59:59.000Z

    A heterodyne terahertz transceiver comprises a quantum cascade laser that is integrated on-chip with a Schottky diode mixer. An antenna connected to the Schottky diode receives a terahertz signal. The quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal. The fully integrated transceiver optimizes power efficiency, sensitivity, compactness, and reliability. The transceiver can be used in compact, fieldable systems covering a wide variety of deployable applications not possible with existing technology.

  18. Integrated heterodyne terahertz transceiver

    DOE Patents [OSTI]

    Wanke, Michael C. (Albuquerque, NM); Lee, Mark (Albuquerque, NM); Nordquist, Christopher D. (Albuquerque, NM); Cich, Michael J. (Albuquerque, NM)

    2012-09-25T23:59:59.000Z

    A heterodyne terahertz transceiver comprises a quantum cascade laser that is integrated on-chip with a Schottky diode mixer. A terahertz signal can be received by an antenna connected to the mixer, an end facet or sidewall of the laser, or through a separate active section that can amplify the incident signal. The quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal. The fully integrated transceiver optimizes power efficiency, sensitivity, compactness, and reliability. The transceiver can be used in compact, fieldable systems covering a wide variety of deployable applications not possible with existing technology.

  19. Observation of Coherently-Enhanced Tunable Narrow-Band Terahertz Transition Radiation from a Relativistic Sub-Picosecond Electron Bunch Train

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

    Piot, P [Northern Illinois U.; Fermilab; Sun, Y E [Fermilab; Maxwell, T J [Fermilab; Northern Illinois U.; Ruan, J.; Lumpkin, A H [Fermilab; Rihaoui, M M [Northern Illinois U.; Thurman-Keup, R [Fermilab

    2011-06-27T23:59:59.000Z

    We experimentally demonstrate the production of narrow-band (?f/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.

  20. Broadband terahertz photonics

    E-Print Network [OSTI]

    Burghoff, David Patrick

    2014-01-01T23:59:59.000Z

    In recent years, quantum cascade lasers have emerged as mature semiconductor sources of light in the terahertz range, the frequency range spanning 1 to 10 THz. Though technological development has pushed their operating ...

  1. Active terahertz metamaterials

    SciTech Connect (OSTI)

    Chen, Hou-tong [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    We demonstrate planar terahertz metamaterial devices enabling actively controllable transmission amplitude, phase, or frequency at room temperature via carrier depletion or photoexcitation in the semiconductor substrate or in semiconductor materials incorporated into the metamaterial structure.

  2. Coherent beam combiner for a high power laser

    DOE Patents [OSTI]

    Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA)

    2002-01-01T23:59:59.000Z

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  3. High-Power Rf Load

    DOE Patents [OSTI]

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

    1998-09-01T23:59:59.000Z

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

  4. Terahertz radiation mixer

    DOE Patents [OSTI]

    Wanke, Michael C. (Albuquerque, NM); Allen, S. James (Santa Barbara, CA); Lee, Mark (Albuquerque, NM)

    2008-05-20T23:59:59.000Z

    A terahertz radiation mixer comprises a heterodyned field-effect transistor (FET) having a high electron mobility heterostructure that provides a gatable two-dimensional electron gas in the channel region of the FET. The mixer can operate in either a broadband pinch-off mode or a narrowband resonant plasmon mode by changing a grating gate bias of the FET. The mixer can beat an RF signal frequency against a local oscillator frequency to generate an intermediate frequency difference signal in the microwave region. The mixer can have a low local oscillator power requirement and a large intermediate frequency bandwidth. The terahertz radiation mixer is particularly useful for terahertz applications requiring high resolution.

  5. Terahertz radiation from laser accelerated electron bunches

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    NUMBER 5 MAY 2004 Terahertz radiation from laser acceleratedand millimeter wave radiation from laser acceleratedNo. 5, May 2004 Terahertz radiation from laser accelerated

  6. High power laser perforating tools and systems

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22T23:59:59.000Z

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  7. HIGH-POWER, HIGH-EFFICIENCY FELS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    M. Kumada, "Scaling of the FEL-ID Equations", ELF Note 128,Instability in a High-power, Short- Wavelength FEL", Proc.of the Ninth FEL" Conference, Williamsburg (1988), and

  8. An ultrafast carbon nanotube terahertz polarisation modulator

    SciTech Connect (OSTI)

    Docherty, Callum J.; Stranks, Samuel D.; Habisreutinger, Severin N.; Joyce, Hannah J.; Herz, Laura M.; Nicholas, Robin J.; Johnston, Michael B., E-mail: m.johnston@physics.ox.ac.uk [Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom)

    2014-05-28T23:59:59.000Z

    We demonstrate ultrafast modulation of terahertz radiation by unaligned optically pumped single-walled carbon nanotubes. Photoexcitation by an ultrafast optical pump pulse induces transient terahertz absorption in nanowires aligned parallel to the optical pump. By controlling the polarisation of the optical pump, we show that terahertz polarisation and modulation can be tuned, allowing sub-picosecond modulation of terahertz radiation. Such speeds suggest potential for semiconductor nanowire devices in terahertz communication technologies.

  9. 36th Annual International Conference on Infrared Millimeter and Terahertz Waves

    SciTech Connect (OSTI)

    Mittleman, Daniel M. [Rice University

    2011-12-31T23:59:59.000Z

    The Major Topic List of the 2011 conference featured a category entitled “IR, millimeter-wave, and THz spectroscopy,” another entitled “Gyro-Oscillators and Amplifiers, Plasma Diagnostics,” and a third called “Free Electron Lasers and Synchrotron Radiation.” Topical areas of interest to meeting participants include millimeter-wave electronics, high-power sources, high-frequency communications systems, and terahertz sensing and imaging, all of which are prominent in the research portfolios of the DOE. The development and study of new materials, components, and systems for use in the IR, THz, and MMW regions of the spectrum are of significant interest as well. a series of technical sessions were organized on the following topics: terahertz metamaterials and plasmonics; imaging techniques and applications; graphene spectroscopy; waveguide concepts; gyrotron science and technology; ultrafast terahertz measurements; and quantum cascade lasers.

  10. Plasma Switch for High-Power Active Pulse Compressor

    SciTech Connect (OSTI)

    Hirshfield, Jay L. [Omega-P, Inc.] [Omega-P, Inc.

    2013-11-04T23:59:59.000Z

    Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

  11. High Power Co-Axial Coupler

    SciTech Connect (OSTI)

    Neubauer, M. [Muons, Inc.; Dudas, A. [Muons, Inc.; Rimmer, Robert A. [JLAB; Guo, Jiquan [JLAB; Williams, R. Scott [JLAB

    2013-12-01T23:59:59.000Z

    A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

  12. Modeling Combustion Control for High Power Diesel Mode Switching...

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

    Combustion Control for High Power Diesel Mode Switching Modeling Combustion Control for High Power Diesel Mode Switching Poster presentation given at the 16th Directions in...

  13. Energy Storage Testing and Analysis High Power and High Energy...

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

    Testing and Analysis High Power and High Energy Development Energy Storage Testing and Analysis High Power and High Energy Development 2009 DOE Hydrogen Program and Vehicle...

  14. USABC Energy Storage Testing - High Power and PHEV Development...

    Energy Savers [EERE]

    Energy Storage Testing - High Power and PHEV Development USABC Energy Storage Testing - High Power and PHEV Development Presentation from the U.S. DOE Office of Vehicle...

  15. Planar Optical Waveguide Coupler Transformers for High-Power...

    Broader source: Energy.gov (indexed) [DOE]

    Planar Optical Waveguide Coupler Transformers for High-Power Solar Enegy Collection and Transmission Planar Optical Waveguide Coupler Transformers for High-Power Solar Enegy...

  16. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    High power density supercapacitors using locally alignedof high power density supercapacitors and other similarcells [6], and for supercapacitors [7–18]. As unique energy

  17. Diffraction mode terahertz tomography

    DOE Patents [OSTI]

    Ferguson, Bradley; Wang, Shaohong; Zhang, Xi-Cheng

    2006-10-31T23:59:59.000Z

    A method of obtaining a series of images of a three-dimensional object. The method includes the steps of transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a two-dimensional array of parallel rays. The optical detection is an array of detectors such as a CCD sensor.

  18. Liquid Walls Innovative High Power Density Concepts

    E-Print Network [OSTI]

    California at Los Angeles, University of

    Surface Heat Flux > 2 MW/m2 2. High Power Conversion Efficiency (> 40%) 3. High Availability -Lower rrr ×= V r J r PV r B r 1P 2P g r + - V r #12;V(initial momentum) g rFluidIn FluidOutBackingWall 2Dsurfaceturbulence · Poloidal Pumping + - J r - flowpoloidal direction - Enhancesurfaceheat transferwith2D turbulence

  19. High power rechargeable batteries Paul V. Braun

    E-Print Network [OSTI]

    Braun, Paul

    and/or self-heating, which ultimately limit the max provide the required electrical output for a given application. It is the cells making up the battery (e.g. fast charging electric vehicles and consumer electronics, high power portable tools, power grid

  20. High Power UV LED Industrial Curing Systems

    SciTech Connect (OSTI)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14T23:59:59.000Z

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  1. Active terahertz metamaterial devices

    DOE Patents [OSTI]

    Chen, Houtong (Los Alamos, NM); Padilla, Willie John (Newton, MA); Averitt, Richard Douglas (Newton, MA); O'Hara, John F. (Los Alamos, NM); Lee, Mark (Albuquerque, NM)

    2010-11-02T23:59:59.000Z

    Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

  2. MI high power operation and future plans

    SciTech Connect (OSTI)

    Kourbanis, Ioanis; /Fermilab

    2008-09-01T23:59:59.000Z

    Fermilab's Main Injector on acceleration cycles to 120 GeV has been running a mixed mode operation delivering beam to both the antiproton source for pbar production and to the NuMI[1] target for neutrino production since 2005. On January 2008 the slip stacking process used to increase the beam to the pbar target was expanded to include the beam to the NuMI target increasing both the beam intensity and power. The current high power MI operation will be described along with the near future plans.

  3. High-Powered Lasers for Clean Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHallNot Logged3 HanfordHarry|High-Powered Lasers

  4. Water Cooling of High Power Light Emitting Diode Henrik Srensen

    E-Print Network [OSTI]

    Berning, Torsten

    Water Cooling of High Power Light Emitting Diode Henrik Sørensen Department of Energy Technology and product lifetime. The high power Light Emitting Diodes (LED) belongs to the group of electronics

  5. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    4484/16/4/003 High power density supercapacitors usingproduced very high speci?c power density of about 30 kW kg ?manufacturing of high power density supercapacitors and

  6. The generation of high field terahertz radiation and its application in terahertz nonlinear spectroscopy

    E-Print Network [OSTI]

    Yeh, Ka-Lo

    2009-01-01T23:59:59.000Z

    In this thesis research, I implemented a terahertz generation scheme that enables high-field near-single-cycle terahertz (THz) pulse generation via optical rectification in a LiNbO3 (LN) crystal. I also developed a method ...

  7. High Power, Linear CMOS Power Amplifier for WLAN Applications /

    E-Print Network [OSTI]

    Afsahi, Ali

    2013-01-01T23:59:59.000Z

    components in silicon, achieving a high power enhancement ratio from a single stage LC matching network or single transformer

  8. High power density solid oxide fuel cells

    SciTech Connect (OSTI)

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  9. Tailored Terahertz Pulses from a Laser-Modulated Electron Beam J. M. Byrd, Z. Hao, M. C. Martin, D. S. Robin, F. Sannibale, R. W. Schoenlein, A. A. Zholents, and M. S. Zolotorev

    E-Print Network [OSTI]

    new development of coherent synchrotron radiation [1] in storage rings. In this Letter, we present a novel method for producing intense temporally and spa- tially coherent synchrotron radiation pulses observations of terahertz signals from sliced beams ob- served at BESSY II, an electron storage ring in Berlin

  10. Terahertz detection and carbon nanotubes

    SciTech Connect (OSTI)

    Leonard, Francois

    2014-06-11T23:59:59.000Z

    Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

  11. Terahertz detection and carbon nanotubes

    ScienceCinema (OSTI)

    Leonard, Francois

    2014-06-13T23:59:59.000Z

    Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

  12. Terahertz antireflection coatings using metamaterials

    SciTech Connect (OSTI)

    Chen, Hou-tong [Los Alamos National Laboratory; Zhou, Jiangfeng [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Azad, Abul K [Los Alamos National Laboratory; Chen, Frank [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    We demonstrate terahertz metamaterial antireflection coatings (ARCs) that significantly reduce the reflection and enhance the transmission at an interface of dielectric media. They are able to operate over a wide range of incidence angles for both TM and TE polarizations. Experiments and finite-element simulations will be presented and discussed.

  13. High power, high beam quality regenerative amplifier

    DOE Patents [OSTI]

    Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Livermore, CA)

    1993-01-01T23:59:59.000Z

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  14. High power THz sources for nonlinear imaging

    SciTech Connect (OSTI)

    Tekavec, Patrick F.; Kozlov, Vladimir G. [Microtech Instruments, 858 West Park Street, Eugene, OR 97401 (United States)

    2014-02-18T23:59:59.000Z

    Many biological and chemical compounds have unique absorption features in the THz (0.1 - 10 THz) region, making the use of THz waves attractive for imaging in defense, security, biomedical imaging, and monitoring of industrial processes. Unlike optical radiation, THz frequencies can pass through many substances such as paper, clothing, ceramic, etc. with little attenuation. The use of currently available THz systems is limited by lack of highpower, sources as well as sensitive detectors and detector arrays operating at room temperature. Here we present a novel, high power THz source based on intracavity downconverison of optical pulses. The source delivers 6 ps pulses at 1.5 THz, with an average power of >300 ?W and peak powers >450 mW. We propose an imaging method based on frequency upconverison that is ideally suited to use the narrow bandwidth and high peak powers produced by the source. By upconverting the THz image to the infrared, commercially available detectors can be used for real time imaging.

  15. High power linear pulsed beam annealer

    DOE Patents [OSTI]

    Strathman, Michael D. (Concord, CA); Sadana, Devendra K. (Berkeley, CA); True, Richard B. (Sunnyvale, CA)

    1983-01-01T23:59:59.000Z

    A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.

  16. High power, high beam quality regenerative amplifier

    DOE Patents [OSTI]

    Hackel, L.A.; Dane, C.B.

    1993-08-24T23:59:59.000Z

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  17. Terahertz generation by two cross focused laser beams in collisional plasmas

    SciTech Connect (OSTI)

    Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

    2014-07-15T23:59:59.000Z

    The role of two cross-focused spatial-Gaussian laser beams has been studied for the high power and efficient terahertz (THz) radiation generation in the collisional plasma. The nonlinear current at THz frequency arises on account of temperature dependent collision frequency of electrons with ions in the plasma and the presence of a static electric field (applied externally in the plasma) and density ripple. Optimisation of laser-plasma parameters gives the radiated THz power of the order of 0.23??MW.

  18. Graphene plasmonics for tunable terahertz metamaterials

    E-Print Network [OSTI]

    Wang, Feng

    Graphene plasmonics for tunable terahertz metamaterials Long Ju1 , Baisong Geng1,6 , Jason Horng1 metamaterials1­3 . Plasmons of two-dimensional massless electrons, as present in graphene, show unusual graphene micro- ribbonarrays.Wedemonstratethatgrapheneplasmonresonances can be tuned over a broad terahertz

  19. Planar Optical Waveguide Coupler Transformers for High-Power...

    Broader source: Energy.gov (indexed) [DOE]

    PLANAR OPTICAL WAVEGUIDE COUPLER TRANSFORMERS FOR HIGH-POWER SOLAR ENERGY COLLECTION AND TRAMSMISSION Nobuhiko P. Kobayashi Baskin School of Engineering, University of California...

  20. High Power Superconducting Continuous Wave Linacs for Protons...

    Office of Science (SC) Website

    research, national security, therapeutic isotopes and transmutation of spent nuclear fuel Argonne National Laboratory has been working on research and development of high power...

  1. Novel Manufacturing Technologies for High Power Induction and...

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

    High Power Induction and Permanent Magnet Electric Motors 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation...

  2. Texas Tech Effort Overview Collaborative Research on Novel High Power

    E-Print Network [OSTI]

    Anlage, Steven

    N) · Nonlinear Transmission lines · High Power Microwave source development · High reprate rf sources · HPM wave Power Microwave breakdown · Vacuum UV Spectroscopy in atmospheric gases · Explosively driven HPM

  3. Modeling Combustion Control for High Power Diesel Mode Switching

    Broader source: Energy.gov (indexed) [DOE]

    Directions in Engine-Efficiency and Emissions Research Conference 2010 Modeling Combustion Control for High Power Diesel Mode Switching Siddhartha Banerjee, Christopher J. Rutland...

  4. Coherent Control of Ballistic Photocurrents in Multilayer Epitaxial Graphene Using Quantum Interference

    E-Print Network [OSTI]

    Recanati, Catherine

    Coherent Control of Ballistic Photocurrents in Multilayer Epitaxial Graphene Using Quantum report generation of ballistic electric currents in unbiased epitaxial graphene at 300 K via quantum. The transient currents are detected via the emitted terahertz radiation. Because of graphene's special structure

  5. Developments and advances in nonlinear terahertz spectroscopy

    E-Print Network [OSTI]

    Brandt, Nathaniel Curran

    2014-01-01T23:59:59.000Z

    Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present ...

  6. Development of terahertz quantum-cascade lasers

    E-Print Network [OSTI]

    Kumar, Sushil, Ph. D. Massachusetts Institute of Technology

    2007-01-01T23:59:59.000Z

    The terahertz or the far-infrared frequency range of the electromagnetic spectrum ( ... ) has historically been technologically underdeveloped despite having many potential applications, primarily due to lack of suitable ...

  7. High-power-density spot cooling using bulk thermoelectrics

    E-Print Network [OSTI]

    Zhang, Y; Shakouri, A; Zeng, G H

    2004-01-01T23:59:59.000Z

    model, the cooling power densities of the devices can alsothe cooling power densities 2–24 times. Experimentally, the14 4 OCTOBER 2004 High-power-density spot cooling using bulk

  8. assisted high power: Topics by E-print Network

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

    V. Braun , Jiung Cho, James H. Pikul, William P. King storage Secondary batteries High energy density High power density Lithium ion battery 3D battery electrodes a b s t r a c t...

  9. Innovative fuel designs for high power density pressurized water reactor

    E-Print Network [OSTI]

    Feng, Dandong, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

  10. Design of annular fuel for high power density BWRs

    E-Print Network [OSTI]

    Morra, Paolo

    2005-01-01T23:59:59.000Z

    Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

  11. High power laser workover and completion tools and systems

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-10-28T23:59:59.000Z

    Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

  12. Apparatus for advancing a wellbore using high power laser energy

    DOE Patents [OSTI]

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02T23:59:59.000Z

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  13. Direct detector for terahertz radiation

    DOE Patents [OSTI]

    Wanke, Michael C. (Albuquerque, NM); Lee, Mark (Albuquerque, NM); Shaner, Eric A. (Albuquerque, NM); Allen, S. James (Santa Barbara, CA)

    2008-09-02T23:59:59.000Z

    A direct detector for terahertz radiation comprises a grating-gated field-effect transistor with one or more quantum wells that provide a two-dimensional electron gas in the channel region. The grating gate can be a split-grating gate having at least one finger that can be individually biased. Biasing an individual finger of the split-grating gate to near pinch-off greatly increases the detector's resonant response magnitude over prior QW FET detectors while maintaining frequency selectivity. The split-grating-gated QW FET shows a tunable resonant plasmon response to FIR radiation that makes possible an electrically sweepable spectrometer-on-a-chip with no moving mechanical optical parts. Further, the narrow spectral response and signal-to-noise are adequate for use of the split-grating-gated QW FET in a passive, multispectral terahertz imaging system. The detector can be operated in a photoconductive or a photovoltaic mode. Other embodiments include uniform front and back gates to independently vary the carrier densities in the channel region, a thinned substrate to increase bolometric responsivity, and a resistive shunt to connect the fingers of the grating gate in parallel and provide a uniform gate-channel voltage along the length of the channel to increase the responsivity and improve the spectral resolution.

  14. A Framework to Simulate and Improve Terahertz Quantum Well

    E-Print Network [OSTI]

    Anderson, Charles H.

    of terahertz radiations to ensure market penetration with practicable civil applications. In that regard, we for terahertz radiations. In fact, medical imaging, homeland security screening, very high-speed wireless telecommunica- tions systems and even drug and gas detection are boosting the development of terahertz emitters

  15. Investigation on reconstruction methods applied to 3D terahertz computed

    E-Print Network [OSTI]

    Boyer, Edmond

    , and D. M. Mittleman, "Imaging with terahertz radiation," Rep. Prog. Phys. 70, 1325-1379 (2007). 2. K. Kawase, Y. Ogawa, Y. Watanabe, and H. Inoue, "Non-destructive terahertz imaging of illicit drugs using. R. Tribe, and M. C. Kemp, "Detection and identification of explosives using terahertz pulsed

  16. Terahertz emission from black silicon M. Theuer,2

    E-Print Network [OSTI]

    of different meth- ods for the generation of terahertz radiation have been devel- oped including pure optical-called photoconductive terahertz emitters and detectors, radiation-damaged silicon on sapphire or low- temperature grown of terahertz optics made out of silicon is that the copropagating infrared radiation is ab- sorbed sufficiently

  17. High-field half-cycle terahertz radiation from relativistic laser interaction with thin solid targets

    SciTech Connect (OSTI)

    Ding, W. J.; Koh, W. S. [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore)] [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Sheng, Z. M. [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2013-11-11T23:59:59.000Z

    It is found that half-cycle terahertz (THz) pulses with the peak field over 100 MV/cm can be produced in ultrashort intense laser interactions with thin solid targets. These THz pulses are shown to emit from both the front and rear sides of the solid target and are attributed to the coherent transition radiation by laser-produced ultrashort fast electron bunches. After the primary THz pulses, subsequent secondary half-cycle pulses are generated while some refluxing electrons cross the vacuum-target interfaces. Since such strong THz radiation is well synchronized with the driving lasers, it is particularly suitable for applications in various pump-probe experiments.

  18. Transmission mode terahertz computed tomography

    DOE Patents [OSTI]

    Ferguson, Bradley Stuart; Wang, Shaohong; Zhang, Xi-Cheng

    2006-10-10T23:59:59.000Z

    A method of obtaining a series of images of a three-dimensional object by transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a scanning spot. The object is placed within the Rayleigh range of the focused THz beam and a focusing system is used to transfer the imaging plane from adjacent the object to a desired distance away from the object. A related system is also disclosed.

  19. Klamath Falls: High-Power Acoustic Well Stimulation Technology

    SciTech Connect (OSTI)

    Black, Brian

    2006-07-24T23:59:59.000Z

    Acoustic well stimulation (AWS) technology uses high-power sonic waves from specific frequency spectra in an attempt to stimulate production in a damaged or low-production wellbore. AWS technology is one of the most promising technologies in the oil and gas industry, but it has proven difficult for the industry to develop an effective downhole prototype. This collaboration between Klamath Falls Inc. and the Rocky Mountain Oilfield Testing Center (RMOTC) included a series of tests using high-power ultrasonic tools to stimulate oil and gas production. Phase I testing was designed and implemented to verify tool functionality, power requirements, and capacity of high-power AWS tools. The purpose of Phase II testing was to validate the production response of wells with marginal production rates to AWS stimulation and to capture and identify any changes in the downhole environment after tool deployment. This final report presents methodology and results.

  20. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    the development of high-power density semiconductor devices.Management of High-Power Density Electronics A DissertationManagement of High-Power Density Electronics by Zhong Yan

  1. Breakdown-prone volume in terahertz wave beams

    SciTech Connect (OSTI)

    Nusinovich, G. S.; Qiao, F.; Kashyn, D. G.; Pu, R. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 (United States)] [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 (United States); Dolin, L. S. [Institute of Applied Physics, Nizhny Novgorod 603600 (Russian Federation)] [Institute of Applied Physics, Nizhny Novgorod 603600 (Russian Federation)

    2013-06-21T23:59:59.000Z

    This study was motivated by the recently proposed concept of remote detection of concealed radioactive materials by a focused terahertz (THz) radiation [V. L. Granatstein and G. S. Nusinovich, J. Appl. Phys. 108, 063304 (2010)]. According to this concept, a high-power THz radiation should be focused in a small spot where the field intensity exceeds the breakdown threshold. In the presence of free electrons in such a breakdown-prone volume, a THz discharge will occur there. However, this volume should be so small that in the absence of ionizing sources in its vicinity the probability to have there any free electrons is low. Then, the increased breakdown rate in a series of THz pulses would indicate the presence of hidden radioactive materials in the vicinity of the focused spot. For this concept, it is important to accurately determine the breakdown-prone volume created by a focused THz radiation. This problem is analyzed in this paper, first, for the case of a single wave beam and, then, for the case of crossing wave beams of different polarizations. The problem is studied first ignoring the diffraction spread of wave beams in the vicinity of the focal plane and, then, with the account for the diffraction spreading. Then, relations between the THz wave power, the range of such a system and the breakdown-prone volume are analyzed. Finally, the effect of the atmospheric turbulence on propagation and focusing of THz wave beams in air is considered.

  2. Science opportunities at high power accelerators like APT

    SciTech Connect (OSTI)

    Browne, J.C.

    1996-12-31T23:59:59.000Z

    This paper presents applications of high power RF proton linear accelerators to several fields. Radioisotope production is an area in which linacs have already provided new isotopes for use in medical and industrial applications. A new type of spallation neutron source, called a long-pulse spallation source (LPSS), is discussed for application to neutron scattering and to the production and use of ultra-cold neutrons (UCN). The concept of an accelerator-driven, transmutation of nuclear waste system, based on high power RF linac technology, is presented along with its impact on spent nuclear fuels.

  3. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, Viet (Seaford, VA); Dylla, III, Henry Frederick (Yorktown, VA)

    1997-01-01T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

  4. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, V.; Dylla, H.F. III

    1997-11-04T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

  5. A new high power, fast charge, sealed lead acid battery

    SciTech Connect (OSTI)

    Juergens, T.; Nelson, R.F.; Ruderman, M.A. [Bolder Technology Corp., Wheat Ridge, CO (United States)

    1994-12-31T23:59:59.000Z

    A new approach to the design of lead acid batteries has been developed based on the use of very thin lead foil current collectors and very high current carrying capacity. The basic cell construction and the performance characteristics for the new cell are described. Spiral wrap cells based on this electrode concept exhibit extremely high power output with excellent capacity maintenance. Additionally, these cells exhibit flat voltage at all currents, and are capable of very rapid recharge. Applications for this high power technology cover a broad spectrum such as portable power tools, UPS systems, electrically heated catalytic converters, pulse power applications and electric and hybrid vehicles. 9 refs.

  6. High power light emitting diode based setup for photobleaching fluorescent impurities

    E-Print Network [OSTI]

    Kaufman, Laura

    High power light emitting diode based setup for photobleaching fluorescent impurities Tobias K be photobleached before final sample preparation. The instrument consists of high power light emitting diodes

  7. High-Power Electrochemical Storage Devices and Plug-in Hybrid...

    Energy Savers [EERE]

    High-Power Electrochemical Storage Devices and Plug-in Hybrid Electric Vehicle Battery Development High-Power Electrochemical Storage Devices and Plug-in Hybrid Electric Vehicle...

  8. Using a Balun Transformer Combiner for High Power Microwave Experiments

    SciTech Connect (OSTI)

    Kaufman, Michael C [ORNL; Pesavento, Philip V [ORNL

    2011-01-01T23:59:59.000Z

    A novel coaxial power combiner design has been duplicated that has distinct advantages over other combiner geometries that can handle high power. This design is being applied to combine four 3 kW power supplies to obtain a 10 kW, 5 MHz system for an ICRF antenna on HSX. In the past, Wilkinson type combiners have had limited application to high power systems because of the lack of non-inductive, high power, 100 Omega balance loads. With this new design, standard 50 Omega dummy loads can be used instead for the balance load. The cost is considerably lower than lumped element combiner designs which are dominated by capacitor costs. At such a relatively low frequency, a 3-dB quarter-wave coupled-line coupler becomes impractically long, and a conventional branch-line hybrid requires 35 Omega-line, which is commercially unavailable. The balun combiner uses less transmission line than a ring hybrid and has good bandwidth characteristics even away from its best line impedance. Theoretical calculations and modeling were performed for line impedances from 65 Omega to 75 Omega. Measurements from a low-power test device show excellent agreement with theory, and construction of the high power system is underway.

  9. High-power, high-intensity laser propagation and interactions

    SciTech Connect (OSTI)

    Sprangle, Phillip [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Electrical and Computer Engineering and Physics, University of Maryland, College Park, Maryland 20740 (United States); Hafizi, Bahman [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2014-05-15T23:59:59.000Z

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  10. A SIMPLIFIED ANALYSIS FOR HIGH POWER MICROWAVE BANDPASS FILTER STRUCTURES

    E-Print Network [OSTI]

    Yu, Ming

    and wireless diplexers. An exact analysis of the voltage/power distribution inside a filter involves the 3D is derived. This transformation is then used to relate the actual voltage distribution inside a transmissionA SIMPLIFIED ANALYSIS FOR HIGH POWER MICROWAVE BANDPASS FILTER STRUCTURES Apu Sivadas, Ming Yu

  11. Cooling System for the MERIT High-Power Target Experiment

    E-Print Network [OSTI]

    McDonald, Kirk

    and a remote PVSS supervision station connected via Ethernet. Operation Modes: Cooling of proximity cryogenicsCooling System for the MERIT High-Power Target Experiment Haug F., Pereira H., Silva P., Pezzetti M a free mercury jet inside a normal conducting pulsed 15 T capture solenoid magnet cooled with liquid

  12. Thin liquid lithium targets for high power density

    E-Print Network [OSTI]

    McDonald, Kirk

    High charge state High velocity flow ~60 m/s High heat capacity of Li Absorbs power depositedThin liquid lithium targets for high power density applications: heavy ion beam strippers and beta Hilton Malmö City #12;Outline Liquid Lithium Stripper idea for FRIB Brief theory of film stability

  13. Device for wavefront correction in an ultra high power laser

    DOE Patents [OSTI]

    Ault, Earl R. (Livermore, CA); Comaskey, Brian J. (Walnut Creek, CA); Kuklo, Thomas C. (Oakdale, CA)

    2002-01-01T23:59:59.000Z

    A system for wavefront correction in an ultra high power laser. As the laser medium flows past the optical excitation source and the fluid warms its index of refraction changes creating an optical wedge. A system is provided for correcting the thermally induced optical phase errors.

  14. Catalytic Coherence

    E-Print Network [OSTI]

    Johan Aberg

    2014-10-20T23:59:59.000Z

    Due to conservation of energy we cannot directly turn a quantum system with a definite energy into a superposition of different energies. However, if we have access to an additional resource in terms of a system with a high degree of coherence, as for standard models of laser light, we can overcome this limitation. The question is to what extent coherence gets degraded when utilized. Here it is shown that coherence can be turned into a catalyst, meaning that we can use it repeatedly without ever diminishing its power to enable coherent operations. This finding stands in contrast to the degradation of other quantum resources, and has direct consequences for quantum thermodynamics, as it shows that latent energy that may be locked into superpositions of energy eigenstates can be released catalytically.

  15. Retroactive Coherence

    E-Print Network [OSTI]

    J. B. Peterson

    2002-03-15T23:59:59.000Z

    In gravitational microlensing, interference visibility is established when the spectral resolution of the observation is less than the reciprocal of the time delay difference. Using high resolutionspectroscopy fringes will be visible at large path differences, even when the source emission is incoherent. This is possible because coherence can be established after interference has already occurred. Results of a laboratory test are presented which demonstrate this retroactive establishment of coherence.

  16. High power semiconductor laser sources. Annual report, 12 March 1985-11 March 1986

    SciTech Connect (OSTI)

    Lang, R.; Salzman, J.; Yariv

    1986-06-10T23:59:59.000Z

    Unstable semiconductor lasers were fabricated, and their potential as high power laser sources was analyzed.

  17. Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)

    E-Print Network [OSTI]

    Berwald, D H; Myers, T J; Paulson, C C; Peacock, M A; Piaszczyk, C M; Rathke, J W; Piechowiak, E M

    1996-01-01T23:59:59.000Z

    Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)

  18. Designing high power targets with computational fluid dynamics (CFD)

    SciTech Connect (OSTI)

    Covrig, S. D. [Thomas Jefferson National Laboratory, Newport News, VA 23606 (United States)

    2013-11-07T23:59:59.000Z

    High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 ?A rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 ?A beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

  19. Video-rate terahertz electric-field vector imaging

    SciTech Connect (OSTI)

    Takai, Mayuko; Takeda, Masatoshi; Sasaki, Manabu; Tachizaki, Takehiro; Yasumatsu, Naoya; Watanabe, Shinichi, E-mail: watanabe@phys.keio.ac.jp [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan)

    2014-10-13T23:59:59.000Z

    We present an experimental setup to dramatically reduce a measurement time for obtaining spatial distributions of terahertz electric-field (E-field) vectors. The method utilizes the electro-optic sampling, and we use a charge-coupled device to detect a spatial distribution of the probe beam polarization rotation by the E-field-induced Pockels effect in a ?110?-oriented ZnTe crystal. A quick rotation of the ZnTe crystal allows analyzing the terahertz E-field direction at each image position, and the terahertz E-field vector mapping at a fixed position of an optical delay line is achieved within 21 ms. Video-rate mapping of terahertz E-field vectors is likely to be useful for achieving real-time sensing of terahertz vector beams, vector vortices, and surface topography. The method is also useful for a fast polarization analysis of terahertz beams.

  20. Method and apparatus for improved high power impulse magnetron sputtering

    DOE Patents [OSTI]

    Anders, Andre

    2013-11-05T23:59:59.000Z

    A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

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

    DOE Patents [OSTI]

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

    1998-01-01T23:59:59.000Z

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

  2. Below gap optical absorption in GaAs driven by intense, single-cycle coherent transition radiation

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

    Goodfellow, J.; Fuchs, M.; Daranciang, D.; Ghimire, S.; Chen, F.; Loos, H.; Reis, D. A.; Fisher, A. S.; Lindenberg, A. M.

    2014-01-01T23:59:59.000Z

    Single-cycle terahertz fields generated by coherent transition radiation from a relativistic electron beam are used to study the high field optical response of single crystal GaAs. Large amplitude changes in the sub-band-gap optical absorption are induced and probed dynamically by measuring the absorption of a broad-band optical beam generated by transition radiation from the same electron bunch, providing an absolutely synchronized pump and probe geometry. This modification of the optical properties is consistent with strong-field-induced electroabsorption. These processes are pertinent to a wide range of nonlinear terahertz-driven light-matter interactions anticipated at accelerator-based sources.

  3. Electron beam diagnostic for profiling high power beams

    DOE Patents [OSTI]

    Elmer, John W. (Danville, CA); Palmer, Todd A. (Livermore, CA); Teruya, Alan T. (Livermore, CA)

    2008-03-25T23:59:59.000Z

    A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

  4. COMPARATIVE STUDIES OF PROTON ACCELERATORS FOR HIGH POWER APPLICATIONS.

    SciTech Connect (OSTI)

    WENG, W.T.

    2006-05-29T23:59:59.000Z

    There are many applications requiring high power proton accelerators of various kinds. However, each type of proton accelerator can only provide beam with certain characteristics, hence the match of accelerators and their applications need careful evaluation. In this talk, the beam parameters and performance limitations of linac, cyclotron, synchrotron, and FFAG accelerators are studied and their relative merits for application in neutron, muon, neutrino, and ADS will be assessed in terms of beam energy, intensity, bunch length, repetition rate, and beam power requirements. A possible match between the applications and the accelerator of choice is presented in a matrix form. The accelerator physics and technology issues and challenges involved will also be discussed.

  5. High-Power Microwave Switch Employing Electron Beam Triggering

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-09-19T23:59:59.000Z

    A high-power active microwave pulse compressor is described that modulates the quality factor Q of the energy storage cavity by a new means involving mode conversion controlled by a triggered electron-beam discharge through a switch cavity. The electron beam is emitted from a diamond-coated molybdenum cathode. This report describes the principle of operation, the design of the switch, the configuration used for the test, and the experimental results. The pulse compressor produced output pulses with 140 - Ã?Â?165 MW peak power, power gain of 16 - 20, and pulse duration of 16 - 20 ns at a frequency of 11.43 GHz.

  6. Plasma relaxation mechanics of pulsed high power microwave surface flashover

    SciTech Connect (OSTI)

    Beeson, S.; Dickens, J.; Neuber, A. [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)] [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)

    2013-09-15T23:59:59.000Z

    Microwave transmission and reflection characteristics of pulsed radio frequency field generated plasmas are elucidated for air, N{sub 2}, and He environments under pressure conditions ranging from 10 to 600 torr. The pulsed, low temperature plasma is generated along the atmospheric side of the dielectric boundary between the source (under vacuum) and the radiating environment with a thickness on the order of 5 mm and a cross sectional area just smaller than that of the waveguide. Utilizing custom multi-standard waveguide couplers and a continuous low power probing source, the scattering parameters were measured before, during, and after the high power microwave pulse with emphasis on the latter. From these scattering parameters, temporal electron density estimations (specifically the longitudinal integral of the density) were calculated using a 1D plane wave-excited model for analysis of the relaxation processes associated. These relaxation characteristics ultimately determine the maximum repetition rate for many pulsed electric field applications and thus are applicable to a much larger scope in the plasma community than just those related to high power microwaves. This manuscript discusses the diagnostic setup for acquiring the power measurements along with a detailed description of the kinematic and chemical behavior of the plasma as it decays down to its undisturbed state under various gas type and pressure conditions.

  7. High power RF systems for the BNL ERL project

    SciTech Connect (OSTI)

    Zaltsman, A.; Lambiase, R.

    2011-03-28T23:59:59.000Z

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

  8. Uppsala High Power Test Stand for ESS Spoke Cavities

    E-Print Network [OSTI]

    Yogi, RA; Dancila, D; Gajewski, K; Hermansson, L; Noor, M; Wedberg, R; Santiago-Kern, R; Ekelöf, T; Lofnes, T; Ziemann, V; Goryashko, V; Ruber, R

    2013-01-01T23:59:59.000Z

    The European Spallation Source (ESS) is one of the world’s most powerful neutron source. The ESS linac will accelerate 50mA pulse current of protons to 2.5GeV in 2.86 ms long pulses at a repetition rate of 14 Hz. It produces a beam with 5MW average power and 125MW peak power. ESS Spoke Linac consist of 28 superconducting spoke cavities, which will be developed by IPN Orsay, France. These Spoke Cavities will be tested at low power at IPN Orsay and high power testing will be performed in a high power test stand at Uppsala University. The test stand consists of tetrode based RF amplifier chain (352MHz, 350 kW) power and related RF distribution. Outputs of two tetrodes shall be combined with the hybrid coupler to produce 350 kW power. Preamplifier for a tetrode shall be solid state amplifier. As the spoke cavities are superconducting, the test stand also includes horizontal cryostat, Helium liquefier, test bunker etc. The paper describes features of the test stand in details.

  9. R&D ERL: High power RF systems

    SciTech Connect (OSTI)

    Zaltsman, A.

    2010-01-15T23:59:59.000Z

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

  10. Surface Plasmon Resonance-like integrated sensor at terahertz

    E-Print Network [OSTI]

    Skorobogatiy, Maksim

    Surface Plasmon Resonance-like integrated sensor at terahertz frequencies for gaseous analytes´ebec H3C3A7, Canada Abstract: Plasmon-like excitation at the interface between fully polymeric fiber sensor and gaseous analyte is demonstrated theoretically in terahertz regime. Such plasmonic excitation

  11. Plasma characterization with terahertz timedomain measurements S. P. Jamisona)

    E-Print Network [OSTI]

    Strathclyde, University of

    Plasma characterization with terahertz time­domain measurements S. P. Jamisona) Department­domain spectral techniques are applied to the characterization of a He discharge plasma. Electro-optically sampling of the electric field of a quasi-unipolar terahertz pulse transmitted through the plasma has

  12. Porous polymer fibers for low-loss Terahertz guiding

    E-Print Network [OSTI]

    Skorobogatiy, Maksim

    of this fiber type is also compared to that of the equivalent sub-wavelength rod-in-the-air fiber the collective vibrational dynamics of a protein in liquid water by terahertz absorption spectroscopy", Protein. Kawase, "Laser terahertz-emission microscope for inspecting electrical faults in integrated circuits

  13. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

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

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; et al

    2015-05-01T23:59:59.000Z

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

  14. KT McDonald 4th High-Power Targetry Workshop May 2, 2011 1 The High-Power Target System

    E-Print Network [OSTI]

    McDonald, Kirk

    in system! Targets for 2-4 MW Proton Beams No such thing as "solid-target-only" at this power level. #12;KT that will be limited to less than 2 MW, static solid targets continue to be appealing. #12;KT McDonald 4th High-PowerKT McDonald 4th High-Power Targetry Workshop May 2, 2011 1 The High-Power Target System for a Muon

  15. Excitation of terahertz nanoantennas by Rabi waves

    SciTech Connect (OSTI)

    Slepyan, G. Ya.; Yerchak, Y. D.; Maksimenko, S. A. [Institute for Nuclear Problems, Belarus State University, Bobruiskaya 11, 220030 Minsk (Belarus); Hoffmann, A. [Institut fuer Festkoerperphysik, Technische Universitaet Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); Bass, F. G. [Department of Physics, Bar-Ilan University, 52900 Ramat-Gan (Israel)

    2011-10-03T23:59:59.000Z

    Theoretical model of quantum dot ring, strongly coupled with classical electromagnetic field, is developed. We demonstrate, that tunnel current in the QD-ring has low-frequency component, excited by Rabi waves, propagating into the ring, and the ring can be considered as a candidate for role of terahertz magnetic loop antenna. The low-frequency current is inspired by the asymmetry of electron tunneling.

  16. High mobility ZnO nanowires for terahertz detection applications

    SciTech Connect (OSTI)

    Liu, Huiqiang [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Peng, Rufang, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn; Chu, Shijin [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Chu, Sheng, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China)

    2014-07-28T23:59:59.000Z

    An oxide nanowire material was utilized for terahertz detection purpose. High quality ZnO nanowires were synthesized and field-effect transistors were fabricated. Electrical transport measurements demonstrated the nanowire with good transfer characteristics and fairly high electron mobility. It is shown that ZnO nanowires can be used as building blocks for the realization of terahertz detectors based on a one-dimensional plasmon detection configuration. Clear terahertz wave (?0.3?THz) induced photovoltages were obtained at room temperature with varying incidence intensities. Further analysis showed that the terahertz photoresponse is closely related to the high electron mobility of the ZnO nanowire sample, which suggests that oxide nanoelectronics may find useful terahertz applications.

  17. Failure modes in high-power lithium-ion batteries for use in hybrid electric vehicles

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    for ATD 18650 GEN 1 lithium ion cells, Revision 4, DecemberFAILURE MODES IN HIGH-POWER LITHIUM-ION BATTERIES FOR USE INdevelopment of high-power lithium-ion batteries for hybrid

  18. High-Powered Dark Energy Camera Can See Billions of Light Years...

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

    High-Powered Dark Energy Camera Can See Billions of Light Years Away High-Powered Dark Energy Camera Can See Billions of Light Years Away August 21, 2014 - 10:19am Addthis Stars...

  19. Boosted HCCI for High Power without Engine Knock, and with Ultra...

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

    Boosted HCCI for High Power without Engine Knock, and with Ultra-Low NOX Emissions Boosted HCCI for High Power without Engine Knock, and with Ultra-Low NOX Emissions Advanced...

  20. OPTIMIZATION OF THE PARAMETERS OF A STORAGE RING FOR A HIGH POWER XUV FREE ELECTRON LASER

    E-Print Network [OSTI]

    Jackson, A.

    2010-01-01T23:59:59.000Z

    A.M. Sessler. 'free Electron Laser . LBL -l 8905 (JanuaryFOR A HIGH POWER XUV FREE ELECTRON LASER. A. Jackson, J.for a High Power XUV Free Electron Laser," (LBL'19771, June,

  1. High-power single mode solid state laser with short wide unstable cavity: Misprints

    E-Print Network [OSTI]

    Kouznetsov, Dmitrii

    1 High-power single mode solid state laser with short wide unstable cavity: Misprints D. Kouznetsov. Kouznetsov, J.-F. Bisson, K. Takaichi K. Ueda. High-power single mode solid state laser with short wide

  2. Failure modes in high-power lithium-ion batteries for use in hybrid electric vehicles

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    MODES IN HIGH-POWER LITHIUM-ION BATTERIES FOR USE IN HYBRIDof high-power lithium-ion batteries for hybrid electricthe development of lithium-ion batteries for hybrid electric

  3. The Neutrino Factory and Muon Collider Collaboration High-Power Targets and Particle Collection

    E-Print Network [OSTI]

    McDonald, Kirk

    Collaboration High-Power Targets Essential for Many Future Facilties ESS IFMIF ISOL/ Beams PSI APT ATW Kirk T

  4. Applications of Ultrafast Terahertz Pulses for Intra-Excitonic Spectroscopy of Quasi-2D Electron-Hole Gases

    E-Print Network [OSTI]

    Kaindl, Robert A.; Carnahan, Marc A.; Hagele, Daniel; Chemla, D.S.

    2006-01-01T23:59:59.000Z

    Applications of Ultrafast Terahertz Pulses for Intra-the utilization of ultrafast terahertz (THz) pulses for theUltrafast Terahertz” 250-kHz Ti:Sapphire Regenerative Amplifier System Pulse

  5. Amplitude Noise and Timing Jitter Characterization of a High-Power

    E-Print Network [OSTI]

    Keller, Ursula

    Amplitude Noise and Timing Jitter Characterization of a High-Power Mode-Locked Integrated External and Timing Jitter Characterization of a High-Power Mode-Locked Integrated External-Cavity Surface Emitting present a timing jitter and amplitude noise characterization of a high-power mode-locked integrated

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

    SciTech Connect (OSTI)

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

    1989-01-01T23:59:59.000Z

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

  7. New developments for high power electron beam equipment

    SciTech Connect (OSTI)

    Melde, C.; Jaesch, G.; Maedler, E. [Von Ardenne Anlagentechnnik GmbH, Dresden (Germany)

    1994-12-31T23:59:59.000Z

    High power electron guns for industrial use work in the range of power of more than 10 kW up to 1200 kW. The only suitable principle for this purpose is that used in axial guns. Elements necessary for these EB guns and their design are described. The outstanding properties required for applications in production and R & D can only be achieved if the equipment is supplemented by a high voltage supply, beam guidance supply, vacuum generator and the various devices for observation, measurement and control. Standard rules for both the technical demands in application and dimensioning of some of the necessary components are explained. Special developments, such as high speed deflection, observation by BSE-camera and arc-free electron beam systems are also presented.

  8. Current and Future High Power Operation of Fermilab Main Injector

    SciTech Connect (OSTI)

    Kourbanis, I.; Adamson, P.; Brown, B.; Capista, D.; Chou, W.; Morris, D.; Seyia, K.; Wu, G.; Yang, M.J.; /Fermilab

    2009-04-01T23:59:59.000Z

    Fermilab's Main Injector on acceleration cycles to 120 GeV has been running a mixed mode operation delivering beam to both the antiproton source for pbar production and to the NuMI[1] target for neutrino production since 2005. On January 2008 the slip stacking process used to increase the beam to the pbar target was expanded to include the beam to the NuMI target increasing the MI beam power at 120 GeV to 400KW. The current high power MI operation will be described along with the plans to increase the power to 700KW for NOvA and to 2.1 MW for project X.

  9. Very low pressure high power impulse triggered magnetron sputtering

    DOE Patents [OSTI]

    Anders, Andre; Andersson, Joakim

    2013-10-29T23:59:59.000Z

    A method and apparatus are described for very low pressure high powered magnetron sputtering of a coating onto a substrate. By the method of this invention, both substrate and coating target material are placed into an evacuable chamber, and the chamber pumped to vacuum. Thereafter a series of high impulse voltage pulses are applied to the target. Nearly simultaneously with each pulse, in one embodiment, a small cathodic arc source of the same material as the target is pulsed, triggering a plasma plume proximate to the surface of the target to thereby initiate the magnetron sputtering process. In another embodiment the plasma plume is generated using a pulsed laser aimed to strike an ablation target material positioned near the magnetron target surface.

  10. High power battery test methods for hybrid vehicle applications

    SciTech Connect (OSTI)

    Hunt, G.L.; Haskins, H.; Heinrich, B.; Sutula, R.

    1997-11-01T23:59:59.000Z

    Commonly used EV battery tests are not very suitable for testing hybrid vehicle batteries, which may be primarily intended to supply vehicle acceleration power. The capacity of hybrid vehicle batteries will be relatively small, they will typically operate over a restricted range of states-of-charge, and they may seldom if ever be fully recharged. Further, hybrid propulsion system designs will commonly impose a higher regeneration content than is typical for electric vehicles. New test methods have been developed for use in characterizing battery performance and life for hybrid vehicle use. The procedures described in this paper were developed from the requirements of the government-industry cooperative Partnership for A New Generation of Vehicles (PNGV) program; however, they are expected to have broad application to the testing of energy storage devices for hybrid vehicles. The most important performance measure for a high power battery is its pulse power capability as a function of state-of-charge for both discharge and regeneration pulses. It is also important to characterize cycle life, although the {open_quote}cycles{close_quote} involved are quite different from the conventional full-discharge, full-recharge cycle commonly used for EV batteries, This paper illustrates in detail several test profiles which have been selected for PNGV battery testing, along with some sample results and lessons learned to date from the use of these test profiles. The relationship between the PNGV energy storage requirements and these tests is described so that application of the test methods can be made to other hybrid vehicle performance requirements as well. The resulting test procedures can be used to characterize the pulse power capability of high power energy storage devices including batteries and ultracapacitors, as well as the life expectancy of such devices, for either power assist or dual mode hybrid propulsion system designs.

  11. Flexible Terahertz Metamaterials: Towards a Terahertz Metamaterial Invisible Cloak , N. I. Landy2

    E-Print Network [OSTI]

    In this work, we present flexible metamaterials on free standing polyimide substrates operating at terahertz fabricated on 5.5m thick polyimide substrates. The samples include purely electric resonator (#1 of the polyimide substrate; w, line width; l, length of the gap; g, gap distance. The SRR structure can be tuned

  12. Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures

    SciTech Connect (OSTI)

    Azad, Abul K [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Han, Jiaguang [OSU; Lu, Xinchao [OSU; Zhang, Weili [OSU

    2009-01-01T23:59:59.000Z

    The fascinating properties of plasmonic structures have had significant impact on the development of next generation ultracompact photonic and optoelectronic components. We study two-dimensional plasmonic structures functioning at terahertz frequencies. Resonant terahertz response due to surface plasmons and dipole localized surface plasmons were investigated by the state-of-the-art terahertz time domain spectroscopy (THz-TDS) using both transmission and reflection configurations. Extraordinary terahertz transmission was demonstrated through the subwavelength metallic hole arrays made from good conducting metals as well as poor metals. Metallic arrays m!lde from Pb, generally a poor metal, and having optically thin thicknesses less than one-third of a skin depth also contributed in enhanced THz transmission. A direct transition of a surface plasmon resonance from a photonic crystal minimum was observed in a photo-doped semiconductor array. Electrical controls of the surface plasmon resonances by hybridization of the Schottkey diode between the metallic grating and the semiconductor substrate are investigated as a function of the applied reverse bias. In addition, we have demonstrated photo-induced creation and annihilation of surface plasmons with appropriate semiconductors at room temperature. According to the Fano model, the transmission properties are characterized by two essential contributions: resonant excitation of surface plasmons and nonresonant direct transmission. Such plasmonic structures may find fascinating applications in terahertz imaging, biomedical sensing, subwavelength terahertz spectroscopy, tunable filters, and integrated terahertz devices.

  13. Features of plasma glow in low pressure terahertz gas discharge

    SciTech Connect (OSTI)

    Bratman, V. L.; Golubev, S. V.; Izotov, I. V.; Kalynov, Yu. K.; Koldanov, V. A.; Razin, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation)] [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Litvak, A. G.; Sidorov, A. V.; Skalyga, V. A.; Zorin, V. G. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation) [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation)

    2013-12-15T23:59:59.000Z

    Investigations of the low pressure (1–100 Torr) gas discharge in the powerful (1 kW) quasi-optical terahertz (0.55 THz) wave beams were made. An intense afterglow was observed after the end of gyrotron terahertz radiation pulse. Afterglow duration significantly exceeded radiation pulse length (8 ?s). This phenomenon could be explained by the strong dependence of the collisional-radiative recombination rate (that is supposed to be the most likely mechanism of electron losses from the low pressure terahertz gas discharge) on electron temperature.

  14. Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS

    E-Print Network [OSTI]

    Agarwalla, Sanjib Kumar; Prakash, Suprabh

    2014-01-01T23:59:59.000Z

    A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity to the measurement of CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 4sigma sensitivity to CP violation for 59% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 4sigma sensitivity for 51% of true values of deltaCP. On the other hand, for the discovery of a...

  15. High Power RF Test Facility at the SNS

    SciTech Connect (OSTI)

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

    2005-05-16T23:59:59.000Z

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

  16. Advanced, High Power, Next Scale, Wave Energy Conversion Device

    SciTech Connect (OSTI)

    Mekhiche, Mike [Principal Investigator] [Principal Investigator; Dufera, Hiz [Project Manager] [Project Manager; Montagna, Deb [Business Point of Contact] [Business Point of Contact

    2012-10-29T23:59:59.000Z

    The project conducted under DOE contract DE?EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven?stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy? technology to deliver a device with much increased power delivery. Scaling?up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke? unlimited Power Take?Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

  17. High power linear pulsed beam annealer. [Patent application

    DOE Patents [OSTI]

    Strathman, M.D.; Sadana, D.K.; True, R.B.

    1980-11-26T23:59:59.000Z

    A high power pulsed electron beam system for annealing semiconductors is comprised of an electron gun having a heated cathode, control grid and focus ring for confining the pulsed beam of electrons to a predetermined area, and a curved drift tube. The drift tube and an annular Faraday shield between the focus ring and the drift tube are maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring, thereby eliminating space charge limitations on the emission of electrons from said gun. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube. The magnetic field produced by the coil around the curved tube imparts motion to electrons in a spiral path for shallow penetration of the electrons into a target. It also produces a scalloped profile of the electron beam. A second drift tube spaced a predetermined distance from the curved tube is positioned with its axis aligned with the axis of the first drift tube. The second drift tube and the target holder are maintained at a reference voltage between the cathode voltage and the curved tube voltage to decelerate the electrons. A second coil surrounding the second drift tube, maintains the electron beam focused about the axis of the second drift tube. The magnetic field of the second coil comprises the electron beam to the area of the semiconductor on the target holder.

  18. Plasma potential mapping of high power impulse magnetron sputtering discharges

    SciTech Connect (OSTI)

    Rauch, Albert; Mendelsberg, Rueben J.; Sanders, Jason M.; Anders, Andre

    2011-12-20T23:59:59.000Z

    Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for pulse length of 100 ?s at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were taken with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target’s racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic pre-sheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons’ E×B drift velocity, which is about 105 m/s and shows structures in space and time.

  19. Terahertz radiation from a laser plasma filament

    SciTech Connect (OSTI)

    Wu, H.-C.; Meyer-ter-Vehn, J. [Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Ruhl, H. [Department fuer Physik der Ludwig-Maximillians-Universitaet, Theresienstrasse 37A, D-80333 Muenchen (Germany); Sheng, Z.-M. [Institute of Plasma Studies, Department of Physics, Shanghai Jiaotong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

    2011-03-15T23:59:59.000Z

    By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect.

  20. Patent: Tunable terahertz radiation source | DOEpatents

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

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

  1. Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators

    E-Print Network [OSTI]

    Kohen, Stephen Michael, 1980-

    2004-01-01T23:59:59.000Z

    Finite-element numerical modeling and analysis of electromagnetic waveguides and resonators used in terahertz (THz) quantum cascade lasers (QCLs) is presented. Simulations and analysis of two types were performed: ...

  2. Terahertz imaging and quantum cascade laser based devices

    E-Print Network [OSTI]

    Lee, Alan Wei Min

    2010-01-01T23:59:59.000Z

    The terahertz (THz) frequency range (f=0.3-10 THz, [lambda]=30-1000 lam) is much less technologically developed that the adjacent microwave and infrared frequency ranges, but offers several advantages for imaging applications: ...

  3. Design, fabrication and characterization of terahertz quantum-well photodetectors

    E-Print Network [OSTI]

    Huang, Shengxi, S.M. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Terahertz (THz) photodetectors are important in the fully exploration and development of electromagnetic spectrum. However, a fast and sensitive THz photodetector ready for array integration is not available. A THz ...

  4. Development of tunable terahertz quantum cascade wire lasers

    E-Print Network [OSTI]

    Qin, Qi, Ph. D. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    For a long time, terahertz (THz) radiation has been of great interest to scientific community because of its spectroscopic and imaging applications based on its unique properties, such as the capabilities to penetrate many ...

  5. Terahertz superconductor metamaterial Jianqiang Gu,1,2

    E-Print Network [OSTI]

    Oklahoma State University

    School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA, The Key Laboratory of Optoelectronics Information and Technical Science (Ministry of Education), Tianjin behavior of the superconducting metamaterial would lead to development of low loss terahertz switches

  6. Nonlinear Terahertz Metamaterials via Field-Enhanced Carrier Dynamics in GaAs

    E-Print Network [OSTI]

    Fan, Kebin

    We demonstrate nonlinear metamaterial split ring resonators (SRRs) on GaAs at terahertz frequencies. For SRRs on doped GaAs films, incident terahertz radiation with peak fields of ?20–160??kV/cm drives intervalley scattering. ...

  7. Terahertz radiation detection by field effect transistor in magnetic field S. Boubanga-Tombet,1,a

    E-Print Network [OSTI]

    Levelut, Claire

    Terahertz radiation detection by field effect transistor in magnetic field S. Boubanga-Tombet,1,a M; accepted 30 July 2009; published online 19 August 2009 We report on terahertz radiation detection with In

  8. Capacitive charging system for high power battery charging

    SciTech Connect (OSTI)

    NONE

    1998-12-31T23:59:59.000Z

    This document describes a project to design, build, demonstrate, and document a Level 3 capacitive charging system, and it will be based on the existing PEZIC prototype capacitive coupler. The capacitive coupler will be designed to transfer power at a maximum of 600 kW, and it will transfer power by electric fields. The power electronics will transfer power at 100 kW. The coupler will be designed to function with future increases in the power electronics output power and increases in the amp/hours capacity of sealed batteries. Battery charging algorithms will be programmed into the control electronics. The finished product will be a programmable battery charging system capable of transferring 100 kW via a capacitive coupler. The coupler will have a low power loss of less than 25 watts when transferring 240 kW (400 amps). This system will increase the energy efficiency of high power battery charging, and it will enhance mobility by reducing coupler failures. The system will be completely documented. An important deliverable of this project is information. The information will be distributed to the Army`s TACOM-TARDEC`s Advanced Concept Group, and it will be distributed to commercial organizations by the Society of Automotive Engineers. The information will be valuable for product research, development, and specification. The capacitive charging system produced in this project will be of commercial value for future electric vehicles. The coupler will be designed to rapid charge batteries that have a capacity of several thousand amp/hours at hundreds of volts. The charging system built here will rapid charge batteries with several hundred amp/hours capacity, depending on the charging voltage.

  9. Safety approaches for high power modular laser operation

    SciTech Connect (OSTI)

    Handren, R.T.

    1993-03-01T23:59:59.000Z

    Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest has been the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program has progressed to the point where a plant-scale facility to demonstrate commercial feasibility has been built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a >90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities ({approximately}3000 gal) of ethanol dye solutions. The Laboratory`s safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

  10. Probing Neutrino Oscillation Parameters using High Power Superbeam from ESS

    E-Print Network [OSTI]

    Sanjib Kumar Agarwalla; Sandhya Choubey; Suprabh Prakash

    2015-01-04T23:59:59.000Z

    A high-power neutrino superbeam experiment at the ESS facility has been proposed such that the source-detector distance falls at the second oscillation maximum, giving very good sensitivity towards establishing CP violation. In this work, we explore the comparative physics reach of the experiment in terms of leptonic CP-violation, precision on atmospheric parameters, non-maximal theta23, and its octant for a variety of choices for the baselines. We also vary the neutrino vs. the anti-neutrino running time for the beam, and study its impact on the physics goals of the experiment. We find that for the determination of CP violation, 540 km baseline with 7 years of neutrino and 3 years of anti-neutrino (7nu+3nubar) run-plan performs the best and one expects a 5sigma sensitivity to CP violation for 48% of true values of deltaCP. The projected reach for the 200 km baseline with 7nu+3nubar run-plan is somewhat worse with 5sigma sensitivity for 34% of true values of deltaCP. On the other hand, for the discovery of a non-maximal theta23 and its octant, the 200 km baseline option with 7nu+3nubar run-plan performs significantly better than the other baselines. A 5sigma determination of a non-maximal theta23 can be made if the true value of sin^2theta23 lesssim 0.45 or sin^2theta23 gtrsim 0.57. The octant of theta23 could be resolved at 5sigma if the true value of sin^2theta23 lesssim 0.43 or gtrsim 0.59, irrespective of deltaCP.

  11. Optimization Studies for ISOL Type High-Powered Targets

    SciTech Connect (OSTI)

    Remec, Igor [Oak Ridge National Laboratory] [Oak Ridge National Laboratory; Ronningen, Reginald Martin [Michigan State University] [Michigan State University

    2013-09-24T23:59:59.000Z

    The research studied one-step and two-step Isotope Separation on Line (ISOL) targets for future radioactive beam facilities with high driver-beam power through advanced computer simulations. As a target material uranium carbide in the form of foils was used because of increasing demand for actinide targets in rare-isotope beam facilities and because such material was under development in ISAC at TRIUMF when this project started. Simulations of effusion were performed for one-step and two step targets and the effects of target dimensions and foil matrix were studied. Diffusion simulations were limited by availability of diffusion parameters for UCx material at reduced density; however, the viability of the combined diffusion?effusion simulation methodology was demonstrated and could be used to extract physical parameters such as diffusion coefficients and effusion delay times from experimental isotope release curves. Dissipation of the heat from the isotope-producing targets is the limiting factor for high-power beam operation both for the direct and two-step targets. Detailed target models were used to simulate proton beam interactions with the targets to obtain the fission rates and power deposition distributions, which were then applied in the heat transfer calculations to study the performance of the targets. Results indicate that a direct target, with specification matching ISAC TRIUMF target, could operate in 500-MeV proton beam at beam powers up to ~40 kW, producing ~8 1013 fission/s with maximum temperature in UCx below 2200 C. Targets with larger radius allow higher beam powers and fission rates. For the target radius in the range 9-mm to 30-mm the achievable fission rate increases almost linearly with target radius, however, the effusion delay time also increases linearly with target radius.

  12. High-Power Converters and AC Drives IEEE PESC2005 Tutorial

    E-Print Network [OSTI]

    Wu, Bin

    @ee.ryerson.ca http://www.ee.ryerson.ca/~bwu/ 2 High-Power Converters and AC Drives 1. Introduction 2. Cascaded H-Bridge Drives · High-Power Semiconductor Devices High-Power Converters and AC Drives Bin Wu 4High · Multilevel Voltage Source Inverters N dC Cascaded H-bridge (CHB) Inverter dC Two Level Inverter dC Flying

  13. Simulation of terahertz generation in corrugated plasma waveguides

    SciTech Connect (OSTI)

    Pearson, Andrew J.; Palastro, John; Antonsen, Thomas M. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2011-05-15T23:59:59.000Z

    We simulate the response of a corrugated plasma channel to an ultrashort laser pulse in two dimensions with the goal of demonstrating the production of terahertz frequency electromagnetic modes. Corrugated channels support electromagnetic modes that have a Floquet-type dispersion relation and thus consist of a sum of spatial harmonics with subluminal phase velocities. This allows the possibility of phase matching between the ponderomotive potential associated with the laser pulse and the electromagnetic modes of the channel. Since the bandwidth of an ultrashort pulse includes terahertz frequencies, significant excitation of terahertz radiation is possible. Here we consider realistic density profiles to obtain predictions of the terahertz power output and mode structure for a channel with periodic boundary conditions. We then estimate pulse depletion effects from our simulation results. The fraction of laser energy converted to terahertz is independent of laser pulse energy in the linear regime, and we find it to be around 1%. Extrapolating to a pulse energy of 0.5 J gives a terahertz power output of 6 mJ with a pulse depletion length of less than 20 cm.

  14. Characterization of terahertz emission from a dc-biased filament in air

    SciTech Connect (OSTI)

    Chen Yanping; Wang Tiejun; Marceau, Claude; Chin, See Leang [Centre d'Optique, Photonique et Laser (COPL), and Departement de Physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1V 0A6 (Canada); Theberge, Francis; Chateauneuf, Marc; Dubois, Jacques [Defence Research and Development Canada-Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec G3J 1X5 (Canada); Kosareva, Olga [International Laser Center, Physics Department, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

    2009-09-07T23:59:59.000Z

    We demonstrate that the terahertz emission from a dc-biased filament can be regarded as a sum of an elliptically polarized terahertz source (generated by a filament without external electric field) and a linearly polarized terahertz source induced by the external electric field applied to the filament. The peak frequency and linewidth of the linearly polarized terahertz source are related to the average plasma density of the filament.

  15. A New Paradigm in Sources and Physics of High-Power Ionospheric

    E-Print Network [OSTI]

    Anlage, Steven

    materials operated at high power microwave (HPM) devices to replace the current , ionospheric modificaHPM to re-examine the coupling typical university HPM laboratory condi

  16. IEEE ELECTRON DEVICE LETTERS, VOL. 19, NO. 10, OCTOBER 1998 373 Terahertz Detector Utilizing

    E-Print Network [OSTI]

    Salama, Khaled

    IEEE ELECTRON DEVICE LETTERS, VOL. 19, NO. 10, OCTOBER 1998 373 Terahertz Detector Utilizing Two. This result shows the potential for developing a new family of electronics devices--plasma wave electronics devices--operating at terahertz frequencies. Index Terms--HEMT, plasma wave electronics, terahertz de

  17. Fast three-dimensional terahertz computed tomography using real-time line projection of

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Fast three-dimensional terahertz computed tomography using real-time line projection of intense terahertz computed tomography by using real-time line projection of intense terahertz beam generated). 4. B. Ferguson, S. Wang, D. Gray, D. Abbot, and X.-C. Zhang, "T-ray computed tomography," Opt. Lett

  18. Emission of terahertz radiation from SiC Jared H. Strait,a

    E-Print Network [OSTI]

    Afshari, Ehsan

    for the generation of terahertz radiation. The nonlinear optical properties of various SiC polytypes have been previ the terahertz radiation dependence on the optical pump polarization, the pump angle of incidence, and the pump for terahertz emission. Given its material hard- ness, high optical damage threshold, small optical losses

  19. Computed tomography image using sub-terahertz waves generated from a high-T{sub c} superconducting intrinsic Josephson junction oscillator

    SciTech Connect (OSTI)

    Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Markovi?, B. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Mirkovi?, J. [Faculty of Science, University of Montenegro, and CETI, Put Radomira Ivanovica, 81000 Podgorica (Montenegro); Klemm, R. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2385 (United States)

    2014-02-24T23:59:59.000Z

    A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

  20. Study of optical response of high-{Tc} YBaCuO and BaKBiO thin films by terahertz spectroscopy

    SciTech Connect (OSTI)

    Liu, Y.; Gao, F.; Whitaker, J.F.; Uher, C. [Univ. of Michigan, Ann Arbor, MI (United States). Center for Ultrafast Optical Science; Platt, C.E. [Univ. of Illinois, Urbana, IL (United States)

    1994-12-31T23:59:59.000Z

    The authors investigate the superfluid and quasiparticle response for high temperature superconductor films of YBa{sub 2}Cu{sub 3}O{sub 7} and Ba{sub 0.6}K{sub 0.4}BiO{sub 3} under optical radiation. This is done through direct measurement of the complex conductivity of the illuminated superconductors using a coherent terahertz-bandwidth spectroscopy technique. The nature of the detected signals is discussed in the context of bolometric and nonbolometric response.

  1. DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e

    E-Print Network [OSTI]

    DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e± Beam Dumps for TESLA W. Bialowons, M. Maslov, M. Schmitz, V. Sytchev #12;1 Concept of the High Power e± Beam Dumps for TESLA W............................................................................................................... 19 #12;2 1 Introduction The TESLA accelerator is equipped with quite a number of extraction lines

  2. High-power laser beam control by PTR Bragg gratings Igor Ciapurin(1)

    E-Print Network [OSTI]

    Glebov, Leon

    High-power laser beam control by PTR Bragg gratings Igor Ciapurin(1) , Vadim Smirnov(1,2) , George is a photo-thermo-refractive (PTR) glass, and used for high-power laser beam control. Exceptionally narrow. The computer controlled recording setup allowed controlling input angles with accuracy better then 0.25 mrad

  3. Broadband High Power Amplifier using Spatial Power Combining Pengcheng Jia 1

    E-Print Network [OSTI]

    and low noise are among the most important features in amplifier design. Broadband spatial power combining the heat sinking in high power application. A high power amplifier using the compact combiner design maintaining good linearity and improving phase noise of the MMIC amplifiers. Coaxial waveguide was used

  4. Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters

    E-Print Network [OSTI]

    Choueiri, Edgar

    Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters A, 2003 Abstract Thermal effects on direct measurements of the thrust produced by steady-state, high-power. Associate Fellow, AIAA. §Presented at the 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 20-23rd

  5. Terahertz graphene lasers: Injection versus optical pumping

    SciTech Connect (OSTI)

    Ryzhii, Victor; Otsuji, Taiichi [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, Maxim [Computational Nanoelectronics Laboratory, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, Vladimir [Department of Electrical Engineering, University at Buffalo, SUNY, Buffalo, New York 14260-1920 (United States)

    2013-12-04T23:59:59.000Z

    We analyze the formation of nonequilibrium states in optically pumped graphene layers and in forward-biased graphene structures with lateral p-i-n junctions and consider the conditions of population inversion and lasing. The model used accounts for intraband and interband relaxation processes as well as deviation of the optical phonon system from equilibrium. As shown, optical pumping suffers from a significant heating of both the electron-hole plasma and the optical phonon system, which can suppress the formation of population inversion. In the graphene structures with p-i-n junction, the injected electrons and holes have relatively low energies, so that the effect of cooling can be rather pronounced, providing a significant advantage of the injection pumping in realization of graphene terahertz lasers.

  6. Effect of atmospheric conditions on operation of terahertz systems for remote detection of ionizing materials

    SciTech Connect (OSTI)

    Nusinovich, Gregory S.; Kashyn, Dmytro G. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States)] [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States); Tatematsu, Yoshinori; Idehara, Toshitaka [FIR Center, University of Fukui, Fukui 910-8507 (Japan)] [FIR Center, University of Fukui, Fukui 910-8507 (Japan)

    2014-01-15T23:59:59.000Z

    This study was motivated by a new concept of remote detection of concealed radioactive materials by using a high power terahertz (THz) wave beam, which can be focused in a small spot where the wave electric field exceeds the breakdown threshold. In the presence of seed electrons in such a volume, this focusing can initiate the avalanche breakdown. Typically, an ambient density of free electrons is assumed to be at the level of one particle per cubic centimeter. So, when a breakdown-prone volume is smaller than 1 cm{sup 3}, there should be significant difference between the breakdown rates in the case of presence of additional sources of ionization versus its absence. Since the flux density of gamma rays emitted by radioactive materials rapidly falls with the distance from the source, while the intensity of THz waves also decreases with the distance due to wave attenuation in the atmosphere, it is important to find an optimal location of the breakdown to be initiated for a given distance between a radioactive material and a THz antenna. This problem is analyzed in a given paper with the account for not only atmospheric attenuation of THz waves but also the air turbulence.

  7. Plasma Physics Challenges of MMPlasma Physics Challenges of MM--toto--THz and High Power MicrowaveTHz and High Power Microwave

    E-Print Network [OSTI]

    Solid StateSolid State Microwave Power ElectronicsMicrowave Power Electronics · Both convert kinetic Devices (Avg) Vacuum HPM (Peak) Solid State Lasers (Peak) Solid State Devices (Avg) Power(W) (Single ...BUT ... For f > 100 GHz VEDs frontier 1/f2P High power limit for Solid State 1/f 2 and HPM Frontier

  8. Energy resolution of terahertz single-photon-sensitive bolometric detectors

    E-Print Network [OSTI]

    Santavicca, D F; Karasik, B S; Pereverzev, S V; Olaya, D; Gershenson, M E; Frunzio, L; Prober, D E

    2009-01-01T23:59:59.000Z

    We report measurements of the energy resolution of superconducting bolometric detectors with sufficient sensitivity to count single terahertz photons. The detector is a superconducting titanium nanobridge with niobium contacts. The larger superconducting energy gap in the niobium confines excitations in the titanium nanobridge, and the thermal relaxation time is set by electron-phonon coupling in the titanium. A fast microwave pulse is used to simulate a single higher-frequency photon, where the absorbed energy of the pulse is equal to the photon energy. Present devices have a measured intrinsic energy resolution of 6 terahertz, near the predicted value due to intrinsic thermal fluctuation noise.

  9. Graphene surface emitting terahertz laser: Diffusion pumping concept

    SciTech Connect (OSTI)

    Davoyan, Arthur R., E-mail: davoyan@seas.upenn.edu [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019, Russia and Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Morozov, Mikhail Yu.; Popov, Vyacheslav V. [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation)] [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation); Satou, Akira; Otsuji, Taiichi [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)] [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)

    2013-12-16T23:59:59.000Z

    We suggest a concept of a tunable graphene-based terahertz (THz) surface emitting laser with diffusion pumping. We employ significant difference in the electronic energy gap of graphene and a typical wide-gap semiconductor, and demonstrate that carriers generated in the semiconductor can be efficiently captured by graphene resulting in population inversion and corresponding?THz lasing from graphene. We develop design principles for such a laser and estimate its performance. We predict up to 50?W/cm{sup 2} terahertz power output for 100?kW/cm{sup 2} pump power at frequency around 10?THz at room temperature.

  10. Detection of nanosecond-scale, high power THz pulses with a field effect transistor

    SciTech Connect (OSTI)

    Preu, S. [Physics Department and Institute for Terahertz Science and Technology, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Chair for Applied Physics, University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Lu, H.; Gossard, A. C. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Sherwin, M. S. [Physics Department and Institute for Terahertz Science and Technology, University of California, Santa Barbara, California 93106 (United States)

    2012-05-15T23:59:59.000Z

    We demonstrate detection and resolution of high power, 34 ns free electron laser pulses using a rectifying field effect transistor. The detector remains linear up to an input power of 11 {+-} 0.5 W at a pulse energy of 20 {+-} 1 {mu}J at 240 GHz. We compare its performance to a protected Schottky diode, finding a shorter intrinsic time constant. The damage threshold is estimated to be a few 100 W. The detector is, therefore, well-suited for characterizing high power THz pulses. We further demonstrate that the same detector can be used to detect low power continuous-wave THz signals with a post detection limited noise floor of 3.1 {mu}W/{radical}(Hz). Such ultrafast, high power detectors are important tools for high power and high energy THz facilities such as free electron lasers.

  11. Vehicle Technologies Office Merit Review 2014: High Energy High Power Battery Exceeding PHEV-40 Requirements

    Broader source: Energy.gov [DOE]

    Presentation given by [company name] at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high energy high power battery...

  12. Diagnostic Evaluation of Detrimental Phenomena in High-Power Lithium-Ion Batteries

    E-Print Network [OSTI]

    Kostecki, Robert; Lei, Jinglei; McLarnon, Frank; Shim, Joongpyo; Striebel, Kathryn

    2005-01-01T23:59:59.000Z

    Phenomena in High-Power Lithium-Ion Batteries RobertAbstract A pouch-type lithium-ion cell, with graphite anodewith model pouch-type lithium-ion cells, with graphite

  13. Hybrid energy storage test procedures and high power battery project FY-1995 interim report

    SciTech Connect (OSTI)

    Hunt, G.L.

    1995-12-01T23:59:59.000Z

    Near the end of FY 1994, DOE provided funding and guidance to INEL for two separate but closely related tasks involving high power energy storage technology. One task was intended to develop and refine application-specific test procedures appropriate to high power energy storage devices for potential use in hybrid vehicles, including batteries, ultracapacitors, flywheels, and similar devices. The second task was intended to characterize the high power capabilities of presently available battery technologies, as well as eventually to evaluate the potential high power capabilities of advanced battery technologies such as those being developed by the USABC. Since the evaluation of such technologies is necessarily dependent to some extent on the availability of appropriate test methods, these two tasks have been closely coordinated. This report is intended to summarize the activities and results for both tasks accomplished during FY-1995.

  14. High-Efficiency and High-Power CMOS Power Amplifiers for Millimeter-Wave Applications /

    E-Print Network [OSTI]

    Agah, Amir

    2013-01-01T23:59:59.000Z

    K. Han, “W-band, 5W Solid-State Power Amplifier/Combiner,”materials have made high-power solid-state power amplifiersCMOS RF power amplifier for GSM-EDGE,” IEEE J. Solid-State

  15. IN-VEHICLE, HIGH-POWER ENERGY STORAGE SYSTEMS | Department of...

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

    Office Merit Review 2014: Penn State DOE Graduate GATE Program for In-Vehicle, High-Power Energy Storage Systems Penn State DOE GATE Center of Exellence for In-Vehicle,...

  16. NEUTRONIC AND THERMAL HYDRAULIC DESIGNS OF ANNULAR FUEL FOR HIGH POWER DENSITY BWRS

    E-Print Network [OSTI]

    Morra, P.

    As a promising new fuel for high power density light water reactors, the feasibility of using annular fuel for BWR services is explored from both thermal hydraulic and neutronic points of view. Keeping the bundle size ...

  17. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    Turin and A. A. Balandin, Electronics Letters 40, 81 (2004).REFERENCES G. E. Moore, Electronics 38 (1965). E. Pop, Nanofor High-power Electronics” PCSI-38:38th Conference on the

  18. IDENTIFICATION AND CONTROL METHODS FOR HIGH POWER ELECTRON BEAM-DRIVEN MICROWAVE TUBES

    E-Print Network [OSTI]

    concepts to the field of high power microwave (HPM) tubes. These concepts are well known to the control systems community, but have not yet been fully exploited within the HPM community. The simpler

  19. Control of high power pulse extracted from the maximally compressed pulse in a nonlinear optical fiber

    E-Print Network [OSTI]

    Yang, Guangye; Jia, Suotang; Mihalache, Dumitru

    2013-01-01T23:59:59.000Z

    We address the possibility to control high power pulses extracted from the maximally compressed pulse in a nonlinear optical fiber by adjusting the initial excitation parameters. The numerical results show that the power, location and splitting order number of the maximally compressed pulse and the transmission features of high power pulses extracted from the maximally compressed pulse can be manipulated through adjusting the modulation amplitude, width, and phase of the initial Gaussian-type perturbation pulse on a continuous wave background.

  20. The capacitively coupled converter (C³) for high power DC-DC conversion 

    E-Print Network [OSTI]

    Khan, Shahriar

    1992-01-01T23:59:59.000Z

    THE CAPACITIVELY COUPLED CONVERTER (C3) FOR HIGH POWER DC-DC CONVERSION A Thesis by SHAHRIAR KHAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1992 Major Subject: Electrical Engineering THE CAPACITIVELY COUPLED CONVERTER (Cs) FOR HIGH POWER DC-DC CONVERSION A Thesis by SHAHRIAR KHAN Approved as to style and content by: Mehrdad Ehsani (Chair of Committee) Prasad Enjeti...

  1. Methods for enhancing the efficiency of creating a borehole using high power laser systems

    DOE Patents [OSTI]

    Zediker, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-06-24T23:59:59.000Z

    Methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena to enhance the formation of Boreholes. Methods for the laser operations to reduce the critical path for forming a borehole in the earth. These methods can deliver high power laser energy down a deep borehole, while maintaining the high power to perform operations in such boreholes deep within the earth.

  2. Method and system for advancement of a borehole using a high power laser

    DOE Patents [OSTI]

    Moxley, Joel F.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Zediker, Mark S.

    2014-09-09T23:59:59.000Z

    There is provided a system, apparatus and methods for the laser drilling of a borehole in the earth. There is further provided with in the systems a means for delivering high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates, a laser bottom hole assembly, and fluid directing techniques and assemblies for removing the displaced material from the borehole.

  3. Method and apparatus for delivering high power laser energy over long distances

    DOE Patents [OSTI]

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2013-08-20T23:59:59.000Z

    Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  4. Method for large and rapid terahertz imaging

    DOE Patents [OSTI]

    Williams, Gwyn P.; Neil, George R.

    2013-01-29T23:59:59.000Z

    A method of large-scale active THz imaging using a combination of a compact high power THz source (>1 watt), an optional optical system, and a camera for the detection of reflected or transmitted THz radiation, without the need for the burdensome power source or detector cooling systems required by similar prior art such devices. With such a system, one is able to image, for example, a whole person in seconds or less, whereas at present, using low power sources and scanning techniques, it takes several minutes or even hours to image even a 1 cm.times.1 cm area of skin.

  5. Terahertz surface plasmon polaritons on a semiconductor surface structured with

    E-Print Network [OSTI]

    Murphy, Thomas E.

    Terahertz surface plasmon polaritons on a semiconductor surface structured with periodic V-doped silicon surface, using anisotropic wet-etching of crystalline silicon, thereby forming a plasmonic surfaces. © 2013 Optical Society of America OCIS codes: (240.6680) Surface plasmons; (240.6690) Surface

  6. Application of nanoporous silicon substrates for terahertz spectroscopy

    E-Print Network [OSTI]

    Murphy, Thomas E.

    molecule," Spectrochim. Acta 61, 2741­2746 (2005). 4. M. Kutteruf, C. Brown, L. Iwaki, M. Campbell, T 1. M. van Exter, C. Fattinger, and D. Grischkowsky, "Terahertz time-domain spectroscopy of water acid molecule," J. Raman Spectrosc. 14, 347­352 (1983). 7. E. J. Heilweil and D. F. Plusquellic

  7. Title of Dissertation: LASER SWITCHED ELECTRON BEAM MODULATION WITH TERAHERTZ

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of Dissertation: LASER SWITCHED ELECTRON BEAM MODULATION WITH TERAHERTZ APPLICATIONS Jonathan Neumann, PhD 2005 Dissertation Directed By: Dr. Patrick O'Shea, Department of Electrical and Computer Engineering This dissertation describes the exploration of relativistic electron beams modulated

  8. Characterization of bending loss in hollow flexible terahertz waveguides

    E-Print Network [OSTI]

    Massachusetts at Lowell, University of

    and metal/dielectric coated polycarbonate waveguides were investigated using an optically pumped far infrared (FIR) laser at 215 µm. The bending loss of silver coated polycarbonate waveguides were measured. Pedersen, and E. Mueller, "Hollow polycarbonate waveguides with inner Cu coatings for delivery of terahertz

  9. Reflection type of terahertz imaging system using a high-T{sub c} superconducting oscillator

    SciTech Connect (OSTI)

    Kashiwagi, T.; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Markovi?, B.; Mirkovi?, J. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [National Institute for Materials Science, Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-01-13T23:59:59.000Z

    A reflection type of imaging system is shown at sub-terahertz frequencies generated from high-T{sub c} superconducting intrinsic Josephson junction mesa structures fabricated by single crystalline Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} to demonstrate how the sub-terahertz imaging technique using monochromatic radiation is powerful and unique for the variety of practical applications. Several examples are discussed in detail and are compared to other terahertz imaging systems.

  10. Coherent Synchrotron Radiation Analysis

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

    Upton, NY 11973, USA Abstract Coherent Synchrotron Radiation (CSR) effects in bunch compressors are analyzed. Schemes for reducing the CSR effects are presented. 1 INTRODUCTION...

  11. Design, simulation and analysis of a molecular nano-sensor operating at terahertz frequencies for energetic materials.

    E-Print Network [OSTI]

    Shenoy, Sukesh

    2007-09-17T23:59:59.000Z

    to combine the fields of nanotechnology and terahertz science and develop a molecular nano-sensor that operates at terahertz frequencies. I focused our sensing on energetic materials, particularly nitromethane, and conducted an extensive analysis on its...

  12. Generation of terahertz radiation from a low-density plasma slab irradiated by a laser pulse

    SciTech Connect (OSTI)

    Frolov, A. A. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2010-04-15T23:59:59.000Z

    The generation of terahertz electromagnetic radiation when a laser pulse propagates through a low-density plasma slab is considered. It is shown that terahertz waves are excited because of the growth of a weakly damped, antisymmetric leaking mode of the plasma slab. The spectral, angular, and energy parameters of the terahertz radiation are investigated, as well as the spatiotemporal structure of the emitted waves. It is demonstrated that terahertz electromagnetic wave fields are generated most efficiently when the pulse length is comparable to the slab thickness.

  13. Theory of a laser-plasma method for detecting terahertz radiation

    SciTech Connect (OSTI)

    Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Borodin, A. V.; Esaulkov, M. N.; Kuritsyn, I. I.; Shkurinov, A. P. [Moscow State University (Russian Federation)

    2012-06-15T23:59:59.000Z

    A theory is developed for calculating the spectrum and the shape of a terahertz wave packet from the temporal profile of the energy of the second harmonic of the laser field generated during nonlinear interaction of laser and terahertz pulses in an optical-breakdown plasma. The spectral and temporal characteristics of the second-harmonic envelope and a terahertz pulse are shown to coincide only for short laser pulses. For long laser pulses, the second-harmonic spectral line shifts to the red and its temporal profile is determined by the time integral of the electric field of terahertz radiation.

  14. Design of a terahertz parametric oscillator based on a resonant cavity in a terahertz waveguide

    SciTech Connect (OSTI)

    Saito, K., E-mail: k-saito@material.tohoku.ac.jp; Oyama, Y. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11-1021, Aoba-ku, 980-8579 Sendai (Japan); Tanabe, T. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, 980-8577 Sendai (Japan)

    2014-07-28T23:59:59.000Z

    We demonstrate ns-pulsed pumping of terahertz (THz) parametric oscillations in a quasi-triply resonant cavity in a THz waveguide. The THz waves, down converted through parametric interactions between the pump and signal waves at telecom frequencies, are confined to a GaP single mode ridge waveguide. By combining the THz waveguide with a quasi-triply resonant cavity, the nonlinear interactions can be enhanced. A low threshold pump intensity for parametric oscillations can be achieved in the cavity waveguide. The THz output power can be maximized by optimizing the quality factors of the cavity so that an optical to THz photon conversion efficiency, ?{sub p}, of 0.35, which is near the quantum-limit level, can be attained. The proposed THz optical parametric oscillator can be utilized as an efficient and monochromatic THz source.

  15. Graphene vertical hot-electron terahertz detectors

    SciTech Connect (OSTI)

    Ryzhii, V., E-mail: v-ryzhii@riec.tohoku.ac.jp [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Center for Photonics and Infrared Engineering, Bauman Moscow State Technical University and Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Satou, A.; Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States); Shur, M. S. [Departments of Electrical, Electronics, and Systems Engineering and Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2014-09-21T23:59:59.000Z

    We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A{sub 3}B{sub 5} materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

  16. Single mode terahertz quantum cascade amplifier

    E-Print Network [OSTI]

    Ren, Y; Wallis, R.; Shah, Y. D.; Jessop, D. S.; Degl'Innocenti, R.; Klimont, A.; Kamboj, V.; Beere, H. E.; Ritchie, D. A.

    2014-10-06T23:59:59.000Z

    coherent radiation with high signal to noise ratio are required. In fact such devices have already been demonstrated in the master-oscillator power amplifier scheme5 as well as a gain-switched amplifier for ultrafast pulses6. For the master... the amplification of short pulses. So in principle, the straightforward way to achieve a quantum casade (QC) amplifier would require a proper antireflective (AR) coating on the facet to fully suppress the feedback, thus the bare cavity gain could be exploited...

  17. High power x-ray welding of metal-matrix composites

    DOE Patents [OSTI]

    Rosenberg, Richard A. (Naperville, IL); Goeppner, George A. (Orland Park, IL); Noonan, John R. (Naperville, IL); Farrell, William J. (Flossmoor, IL); Ma, Qing (Westmont, IL)

    1999-01-01T23:59:59.000Z

    A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10.sup.4 watts/cm.sup.2 and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

  18. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Song Chi; Ahmed Elasser; Maja Harfman-Todorovic; Yan Jiang; Frank Mueller; Fengfeng Tao

    2012-06-01T23:59:59.000Z

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  19. A MODEL FOR PRODUCING STABLE, BROADBAND TERAHERTZ COHERENT SYNCHROTRON RADIATION IN STORAGE RINGS*

    E-Print Network [OSTI]

    that steady state CSR has been observed for the first time in the BESSY-II storage ring [2, 3]. Coupled be found that the BESSY-II CSR emission belongs to this category. In fact, streak camera measurements for Gaussian bunches and indicating the presence of distorted distributions. Attractive features of the BESSY

  20. Analysis of the Hydration Water around Bovine Serum Albumin using Terahertz Coherent Synchrotron Radiation

    E-Print Network [OSTI]

    Bye, J. W.; Meliga, S.; Ferachou, D.; Cinque, G.; Zeitler, J. A.; Falconer, R. J.

    of the whole protein. 19 Neutron scattering experiments have also shown that scattering profiles for aqueous solutions of apolar amino acid analogs differs from bulk water and hydrophilic amino acid analogs.20 Extended frequency range light scattering...

  1. Diagnostic Characterization of High Power Lithium-Ion Batteries for Use in Hybrid Electric Vehicles

    E-Print Network [OSTI]

    Diagnostic Characterization of High Power Lithium-Ion Batteries for Use in Hybrid Electric Vehicles for perfor- mance characterization of these batteries in HEV applications in contrast to the constant microscopy, atomic force microscopy, gas chromatography, etc., were used to characterize the anode, cathode

  2. Diagnostic Characterization of High-Power Lithium-Ion Batteries For Use in Hybrid Electric Vehicles

    E-Print Network [OSTI]

    Diagnostic Characterization of High-Power Lithium-Ion Batteries For Use in Hybrid Electric Vehicles generated specifically for performance characterization of these batteries in HEV applications in contrast to the constant-current profiles typically used in the characterization of lithium-ion batteries for portable

  3. High-power parametric conversion from near-infrared to short-wave infrared

    E-Print Network [OSTI]

    Dalang, Robert C.

    High-power parametric conversion from near-infrared to short-wave infrared Adrien Billat,1,* Steevy.billat@epfl.ch Abstract: We report the design of an all-fiber continuous wave Short-Wave Infrared source capable to output.4370) Nonlinear optics, fibers; (140.3070) Infrared and far-infrared lasers. References and links 1. M. N

  4. Advanced High Energy and High Power Battery Systems for Automotive Applications Khalil Amine

    E-Print Network [OSTI]

    Levi, Anthony F. J.

    -dependent Industry 41% Oil-dependent 17% Oil-dependent 72% 22% 1% 5% U.S. Oil Consumption by End-use Sector 199.30am Advanced High Energy and High Power Battery Systems for Automotive Applications Khalil Amine Argonne National Laboratory Abstract To meet the high-energy requirem ent that can enab le the 40-miles

  5. LAL/RT 04-03 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY

    E-Print Network [OSTI]

    Boyer, Edmond

    LAL/RT 04-03 April 2004 1 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY T. Garvey, H. Borie, L, Université de Paris-Sud, B.P. 34, 91898 Orsay, France Abstract Within the general TESLA collaboration-Orsay are centred on the development of RF input couplers for the cavities of the TESLA linear collider study

  6. High Power Impulse Magnetron Sputtering deposition of Pt inside fuel cell electrodes

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 High Power Impulse Magnetron Sputtering deposition of Pt inside fuel cell electrodes S Cuynet1 as a cathode of a proton exchange membrane fuel cell. An increase of 80 % at 0.65 V of the PEMFC power density) 272001" #12;2 Proton exchange membrane fuel cells (PEMFC) have the potential to provide

  7. Title of Dissertation: HIGH POWER NONLINEAR PROPAGATION OF LASER PULSES IN TENUOUS GASES

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of Dissertation: HIGH POWER NONLINEAR PROPAGATION OF LASER PULSES IN TENUOUS GASES AND PLASMA CHANNELS Jianzhou Wu, Doctor of Philosophy, 2005 Dissertation Directed By: Professor Thomas M PROPAGATION OF LASER PULSES IN TENUOUS GASES AND PLASMA CHANNELS By Jianzhou Wu Dissertation submitted

  8. Control of high power IGBT modules in the active region for fast pulsed power converters

    E-Print Network [OSTI]

    Cravero, JM; Garcia Retegui, R; Maestri, S; Uicich, G

    2014-01-01T23:59:59.000Z

    At CERN, fast pulsed power converters are used to supply trapezoidal current in different magnet loads. These converters perform output current regulation by using a high power IGBT module in its ohmic region. This paper presents a new strategy for pulsed current control applications using a specifically designed IGBT driver.

  9. Nano-structured anode material for high-power battery system in electric vehicles.

    SciTech Connect (OSTI)

    Amine, K.; Belharouak, I.; Chen, Z.; Taison, T.; Yumoto, H.; Ota, N.; Myung, S.-T.; Sun, Y.-K. (Chemical Sciences and Engineering Division); (Enerdel Lithium Power Systems); (Iwate Univ.); (Hanyang Univ.)

    2010-07-27T23:59:59.000Z

    A new MSNP-LTO anode is developed to enable a high-power battery system that provides three times more power than any existing battery system. It shows excellent cycle life and low-temperature performance, and exhibits unmatched safety characteristics.

  10. Development of high-power electrodes for a liquid-feed direct methanol fuel cell

    E-Print Network [OSTI]

    Development of high-power electrodes for a liquid-feed direct methanol fuel cell C. Lim, C.Y. Wang for a liquid-feed direct methanol fuel cell (DMFC) were fabricated by using a novel method of modi®ed Na.V. All rights reserved. Keywords: Direct methanol fuel cells; Membrane-electrode assembly (MEA); Polymer

  11. Theoretical analysis of the trade-off between efficiency and linearity of the High Power Amplifier

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Theoretical analysis of the trade-off between efficiency and linearity of the High Power Amplifier], the methodology of PA design focuses on a trade-off between linearity and power efficiency represented 47601 F-35576 Cesson-Sevign´e cedex, France Email: {Abel.Gouba, Yves.Louet}@supelec.fr Abstract--Power

  12. Cree's High-Power White LED Delivers 121 lm/W

    Broader source: Energy.gov [DOE]

    Cree's commercial high-power white LEDs can now deliver 121 lm/W at 35A/cm2 current density. These particular Cree XLamp® XP-G LEDs deliver 267 lumens at a drive current of 700 mA and an operating...

  13. Mats Lindroos, Cristina Oyon and Stevey OECD "A High Power Spallation Source in each Global Region"

    E-Print Network [OSTI]

    McDonald, Kirk

    ESS Mats Lindroos, Cristina Oyon and Stevey Peggs #12;ESS 2 #12;OECD "A High Power Spallation Source in each Global Region" SNS Oak Ridge J-PARC Tokai ESS in Lund #12;ESS: Site selection process · ESS high up on the ESFRI list Th ti biddi f th it (Bilb L d d· Three consortia bidding for the site

  14. Electrical characterization and modelling of round spiral supercapacitors for high power applications

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Electrical characterization and modelling of round spiral supercapacitors for high power of supercapacitors under railway and electrical traction constraints. Electrical model parameters according of supercapacitors and give precious information on its state of health. These kinds of studies need a powerful

  15. Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors

    E-Print Network [OSTI]

    Highly Conductive and Porous Activated Reduced Graphene Oxide Films for High-Power Supercapacitors for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films. KEYWORDS: Graphene, flexible film, chemical activation, supercapacitors Free-standing thin film materials

  16. Efficient Transmitters and Receivers for High-Power Wireless Powering Systems

    E-Print Network [OSTI]

    Popovic, Zoya

    Efficient Transmitters and Receivers for High-Power Wireless Powering Systems Zoya Popovic, Tibault of a wireless powering system is maximized when the power transmitter power-added efficiency (PAE), power system, which is valid for any type of wireless power coupling. Experimental results for high

  17. ADVANCES IN HIGH-POWER TARGETS* H. KIRK, BNL, UPTON, NY 11973, U.S.A.

    E-Print Network [OSTI]

    McDonald, Kirk

    is the bulk modules, T is the coefficient of thermal expansion, and CV is the thermal heat capacity, one sees and high values of the heat capacity. Additional material property considerations are a high tensile toward solving the technical challenges of developing high-power targets. To date both solid and liquid

  18. Online Vce measurement method for wear-out monitoring of high power IGBT modules

    E-Print Network [OSTI]

    Munk-Nielsen, Stig

    replacement before switch failure occurs. This lowers the downtime of wind turbines, especially for the off shore wind farm where sea conditions may greatly extend it [3]. Standard multichip IGBT module consistsOnline Vce measurement method for wear-out monitoring of high power IGBT modules Szymon Bczkowski

  19. Title of Document: CHARACTERIZATION AND MODELING OF HIGH POWER MICROWAVE EFFECTS IN

    E-Print Network [OSTI]

    Anlage, Steven

    'Shea, Department of Electrical and Computer Engineering The intentional use of high power microwave (HPM) signals to assess HPM threats involve empirical testing of electronic equipment, which provides no insight into fundamental mechanisms of HPM induced upset. The work presented in this dissertation is part of a broad effort

  20. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in

    E-Print Network [OSTI]

    Ganesan, Sashikumaar

    experiments involving biological tissues. Index Terms--Far infrared, Terahertz Heating, Breast and BrainIEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in real tissues causes heating as with any other electromagnetic radiation propagation. A finite element

  1. Scattering of terahertz radiation on a graphene-based nano-antenna

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    Scattering of terahertz radiation on a graphene-based nano-antenna Ignacio Llatser, , Christian. Scattering of the terahertz radiation on a graphene-based nano-antenna is considered. Different electromagnetic models of graphene are discussed and applied to calculate extinction, scattering and absorption

  2. Terahertz spectroscopy of intrinsic biomarkers for non-melanoma skin Cecil S. Joseph1*

    E-Print Network [OSTI]

    Massachusetts at Lowell, University of

    Terahertz spectroscopy of intrinsic biomarkers for non-melanoma skin cancer. Cecil S. Joseph1 of human cancers. The aim of this study was to identify intrinsic biomarkers for non-melanoma skin cancer wave terahertz imaging, skin cancer imaging 1. INTRODUCTION 1.1 Non-Melanoma Skin Cancer Non-melanoma

  3. Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene

    E-Print Network [OSTI]

    Murphy, Thomas E.

    Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene . The hot-electron photothermoelectric effect in graphene is a prom- ising detection mechanism; photoexcited, we demonstrate a graphene thermoelectric terahertz photodetector with sensi- tivity exceeding 10 V W

  4. Strong Enhancement of Terahertz Radiation from Laser Filaments in Air by a Static Electric Field

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Strong Enhancement of Terahertz Radiation from Laser Filaments in Air by a Static Electric Field radiation from the laser filament is highly sensitive to the presence of a transverse electric field. We observe a three order of magnitude enhancement of the terahertz (THz) energy radiated by a femtosecond

  5. A single-pixel terahertz imaging system based on compressed sensing Wai Lam Chan,a

    E-Print Network [OSTI]

    in areas such as detection of foam insula- tion defects,1 illicit drug detection,2 and package inspection3 insensitive to terahertz radiation, so a bright tera- hertz source is needed.6 Single-shot electro of the object or the terahertz beam. In addition, one would like to preserve the superior detection sensitivity

  6. Tailoring the slow light behavior in terahertz metasurfaces

    E-Print Network [OSTI]

    Manjappa, Manukumara; Cong, Longqing; Bettiol, Andrew A; Zhang, Weili; Singh, Ranjan

    2015-01-01T23:59:59.000Z

    We experimentally study the effect of near field coupling on the transmission of light in terahertz metasurfaces, possessing slightly distinctive SRR resonances. Our results show that the interplay between the strengths of electric and magnetic dipoles, modulates the amplitude of resulting electromagnetically induced transmission, probed under different types of asymmetries in the coupled system. We employ a two-particle model to theoretically study the influence of the near field coupling between bright and quasi-dark modes on the transmission properties of the coupled system and we find an excellent agreement with our observed results. Adding to the enhanced transmission characteristics, our results provide a deeper insight into the metamaterial analogues of atomic electromagnetically induced transparency and offer an approach to engineer slow light devices, broadband filters and attenuators at terahertz frequencies.

  7. Polymer microstructured optical fibers for terahertz wave guiding

    E-Print Network [OSTI]

    Skorobogatiy, Maksim

    . Valdes, F. A. Vallejo, L. M. Hayden, B. Polishak, X.-H. Zhou, J. Luo, A. K. Jen, J. C. Williams, and R. J.6495) Spectroscopy, terahertz. References and links 1. G. Imeshev, M. E. Fermann, K. L. Vodopyanov, M. M. Fejer, X-patterned GaAs pumped by a fiber laser," Opt. Express 14(10), 4439­4444 (2006). 2. M. Tang, H. Minamide, Y

  8. The development of low cost LiFePO4-based high power lithium-ion batteries

    E-Print Network [OSTI]

    Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

    2003-01-01T23:59:59.000Z

    4 , natural graphite, lithium-ion battery, diagnosticsand efficiency of pouch lithium-ion cells for constant C/24 -BASED HIGH POWER LITHIUM-ION BATTERIES Joongpyo Shim,

  9. Diagnostic evaluation of power fade phenomena and calendar life reduction in high-power lithium-ion batteries

    E-Print Network [OSTI]

    Kostecki, Robert; McLarnon, Frank

    2004-01-01T23:59:59.000Z

    LIFE REDUCTION IN HIGH-POWER LITHIUM-ION BATTERIES RobertRaman, AFM Introduction Lithium-ion batteries are being

  10. The development of low cost LiFePO4-based high power lithium-ion batteries

    E-Print Network [OSTI]

    Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

    2003-01-01T23:59:59.000Z

    HIGH POWER LITHIUM-ION BATTERIES Joongpyo Shim, Azucenaof rechargeable lithium batteries for application in hybridin consumer-size lithium batteries, such as the synthetic

  11. Novel Laser-Based Manufacturing of nano-LiFePO4-Based Materials for High Power Li Ion Batteries

    E-Print Network [OSTI]

    Horne, Craig R.; Jaiswal, Abhishek; Chang, On; Crane, S.; Doeff, Marca M.; Wang, Emile

    2006-01-01T23:59:59.000Z

    II “Olivines in Lithium Batteries” The Beckman Institute,for High Power Li Ion Batteries C.R. Horne 1 , A. Jaiswal

  12. The development of low cost LiFePO4-based high power lithium-ion batteries

    E-Print Network [OSTI]

    Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

    2003-01-01T23:59:59.000Z

    study of rechargeable lithium batteries for application inin consumer-size lithium batteries, such as the synthetic4 -BASED HIGH POWER LITHIUM-ION BATTERIES Joongpyo Shim,

  13. Materials data requirements for high power target design E. Noah, 4th HPTW, Malm, SE, 2-6 May 2011

    E-Print Network [OSTI]

    McDonald, Kirk

    : Safety Reliability of components > Motivation for codes and standards: Contractual: client/contractor/supplier. construction qualification. examinations. #12;Materials data requirements for high power target design E

  14. Thermal And Mechanical Analysis of High-power Light-emitting Diodes with Ceramic Packages

    E-Print Network [OSTI]

    J. Hu; L. Yang; M. -W. Shin

    2008-01-07T23:59:59.000Z

    In this paper we present the thermal and mechanical analysis of high-power light-emitting diodes (LEDs) with ceramic packages. Transient thermal measurements and thermo-mechanical simulation were performed to study the thermal and mechanical characteristics of ceramic packages. Thermal resistance from the junction to the ambient was decreased from 76.1 oC/W to 45.3 oC/W by replacing plastic mould to ceramic mould for LED packages. Higher level of thermo-mechanical stresses in the chip were found for LEDs with ceramic packages despite of less mismatching coefficients of thermal expansion comparing with plastic packages. The results suggest that the thermal performance of LEDs can be improved by using ceramic packages, but the mounting process of the high power LEDs with ceramic packages is critically important and should be in charge of delaminating interface layers in the packages.

  15. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited)

    SciTech Connect (OSTI)

    Kubo, S.; Nishiura, M.; Tanaka, K.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahash, H.; Mutoh, T. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, 509-5292 Gifu (Japan); Tamura, N. [Department of Energy Science and Technology, Nagoya University, Nagoya 464-8463 (Japan); Tatematsu, Y.; Saito, T. [Research Center for Development of FIR Region, University of Fukui, Fukui 910-8507 (Japan); Notake, T. [Tera-Photonics Lab., RIKEN, Sendai 980-0845 (Japan); Korsholm, S. B.; Meo, F.; Nielsen, S. K.; Salewski, M.; Stejner, M. [Association EURATOM-Risoe DTU, P.O. Box 49, DK-4000 Roskilde (Denmark)

    2010-10-15T23:59:59.000Z

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.

  16. Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

    E-Print Network [OSTI]

    Toshiyuki Hosoya; Martin Miranda; Ryotaro Inoue; Mikio Kozuma

    2014-12-02T23:59:59.000Z

    We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system, which does not depend on complex nonlinear frequency-doubling, has great importance for implementing transportable optical lattice clocks, and is also useful for investigations on condensed matter physics or quantum information processing using cold atoms.

  17. SAR image effects on coherence and coherence estimation.

    SciTech Connect (OSTI)

    Bickel, Douglas Lloyd

    2014-01-01T23:59:59.000Z

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  18. AlGaAs/GaAs photovoltaic converters for high power narrowband radiation

    SciTech Connect (OSTI)

    Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021 (Russian Federation); Luque, Antonio [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021, Russia and Instituto de Energia Solar, Universidad Politecnica de Madrid, Madrid (Spain)

    2014-09-26T23:59:59.000Z

    AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (? = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

  19. Photoionization of optically trapped ultracold atoms with a high-power light-emitting diode

    SciTech Connect (OSTI)

    Goetz, Simone; Hoeltkemeier, Bastian; Amthor, Thomas; Weidemueller, Matthias [Physikalisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg (Germany)

    2013-04-15T23:59:59.000Z

    Photoionization of laser-cooled atoms using short pulses of a high-power light-emitting diode (LED) is demonstrated. Light pulses as short as 30 ns have been realized with the simple LED driver circuit. We measure the ionization cross section of {sup 85}Rb atoms in the first excited state, and show how this technique can be used for calibrating efficiencies of ion detector assemblies.

  20. Nonlinear excitation of photonikos and plasmons by high-power, short pulse lasers

    E-Print Network [OSTI]

    Levan N. Tsintsadze; Hitoshi Hojo

    2008-10-29T23:59:59.000Z

    Modulational excitation of longitudinal photons (photonikos) and electron Langmuir waves, as well as ion sound waves by an incoherent strong and superstrong radiation (high-power short pulse lasers, non-thermal equilibrium cosmic field radiation, etc.) in plasmas are investigated. A simultaneous generation of photonikos and plasmons are demonstrated. Furthermore, the kinetic instability is considered when a low frequency photonikos are generated alone. Growth rates of these new modes are obtained.

  1. A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

    E-Print Network [OSTI]

    Bombelli, Paolo; Mueller, Thomas; Herling, Therese W.; Howe, Christopher J.; Knowles, Tuomas P. J.

    2014-09-16T23:59:59.000Z

    A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells Paolo Bombelli,1, a) Thomas Mu¨ller,2, a) Therese W. Herling,2 Christopher J. Howe,1, b) and Tuomas P. J. Knowles2, c) 1)Department of Biochemistry... that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic...

  2. High Power Testing of RF Cavities for the PEP II B Factory

    SciTech Connect (OSTI)

    Rimmer, R.A.; /LBL, Berkeley; Allen, M.; Fant, K.; Hill, A.; Hoyt, M.; Judkins, J.; Neubauer, Mark Stephen; Schwarz, H.; /SLAC

    2011-09-01T23:59:59.000Z

    We describe the process of conditioning and high-power testing of RF cavities for PEP-II. Procedures for vacuum assembly, bakeout and automated processing are described. Interlocks and safety precautions for protection of equipment and personnel are discussed and performance data of tested cavity assemblies are reported. Performance of ancillary components such as windows, couplers and tuners is also discussed. Comments are included on handling, alignment, installation and commissioning issues where appropriate.

  3. High-Power Detectors Newport Corporation warrants this product to be free from defects In material and

    E-Print Network [OSTI]

    Kleinfeld, David

    High-Power Detectors #12;Warranty Newport Corporation warrants this product to be free from defects.3 Unpacking and Inspection 2 Section 2 - Detector Operation 2.1 Introduction 3 2.2 Power Signal Behavior 3 2 Reflections 7 2.7 Spectral Response 8 2.8 Care for High-Power Detectors 9 2.9 Detector Recalibration 9 Section

  4. Flux-weakening operation of open-end winding drive integrating a cost effective high-power charger

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Flux-weakening operation of open-end winding drive integrating a cost effective high-power charger-end winding drive integrating a cost effective high-power charger Page 1 of 26 IET Review Copy Only IET Inverter (VSI) and an open-end winding Interior Permanent Magnet Synchronous Machine (IPMSM) designed

  5. Adaptive-feedback spectral-phase control for interactions with transform-limited ultrashort high-power laser pulses

    E-Print Network [OSTI]

    Umstadter, Donald

    Adaptive-feedback spectral-phase control for interactions with transform-limited ultrashort high-power large spectral bandwidths. The availability of ultrashort pulses (femto- second) of high-power (petawatt Powers, Isaac Ghebregziabher, and Donald Umstadter* Department of Physics and Astronomy, University

  6. Ultrathin Spinel LiMn2O4 Nanowires as High Power Cathode Materials for Li-Ion Batteries

    E-Print Network [OSTI]

    Cui, Yi

    Ultrathin Spinel LiMn2O4 Nanowires as High Power Cathode Materials for Li-Ion Batteries Hyun diameters less than 10 nm and lengths of several micrometers. Galvanostatic battery testing showed that Li, lithium ion battery, LiMn2O4 nanowires, high power density, Jahn-Teller distortion T he high energy

  7. Nice, Cte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    generation a part of the input electric power is converted into light, which is described by the wall plugNice, Côte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES D a study of accuracy issues in thermal modeling of high power LED modules on system level. Both physical

  8. 2 nature physics | VOL 2 | JANUARY 2006 | www.nature.com/naturephysics A high-power laser fusion

    E-Print Network [OSTI]

    Loss, Daniel

    -rich `blanket', to release heat to drive a steam turbine power plant and to generate tritium for a subsequentCOMMENTARY 2 nature physics | VOL 2 | JANUARY 2006 | www.nature.com/naturephysics A high-power opportunities for performing fundamental and applied research will be missed. A dedicated civilian high-power

  9. High Power Wideband AlGaN/GaN HEMT Feedback Amplifier Module with Drain and Feedback Loop

    E-Print Network [OSTI]

    Itoh, Tatsuo

    High Power Wideband AlGaN/GaN HEMT Feedback Amplifier Module with Drain and Feedback Loop amplifier module using AlGaN/GaN high electron mobility transistor (HEMT) has been developed that covers radars and communications systems. GaN-based HEMT's for high power applications at microwave frequencies

  10. Coherent Nuclear Radiation

    E-Print Network [OSTI]

    V. I. Yukalov; E. P. Yukalova

    2004-06-22T23:59:59.000Z

    The main part of this review is devoted to the comprehensive description of coherent radiation by nuclear spins. The theory of nuclear spin superradiance is developed and the experimental observations of this phenomenon are considered. The intriguing problem of how coherence develops from initially incoherent quantum fluctuations is analysed. All main types of coherent radiation by nuclear spins are discussed, which are: free nuclear induction, collective induction, maser generation, pure superradiance, triggered superradiance, pulsing superradiance, punctuated superradiance, and induced emission. The influence of electron-nuclear hyperfine interactions and the role of magnetic anisotropy are studied. Conditions for realizing spin superradiance by magnetic molecules are investigated. The possibility of nuclear matter lasing, accompanied by pion or dibaryon radiation, is briefly touched.

  11. Bidirectional coherent classical communication

    E-Print Network [OSTI]

    Aram W. Harrow; Debbie W. Leung

    2005-05-12T23:59:59.000Z

    A unitary interaction coupling two parties enables quantum communication in both the forward and backward directions. Each communication capacity can be thought of as a tradeoff between the achievable rates of specific types of forward and backward communication. Our first result shows that for any bipartite unitary gate, coherent classical communication is no more difficult than classical communication -- they have the same achievable rate regions. Previously this result was known only for the unidirectional capacities (i.e., the boundaries of the tradeoff). We then relate the tradeoff curve for two-way coherent communication to the tradeoff for two-way quantum communication and the tradeoff for coherent communiation in one direction and quantum communication in the other.

  12. Theoretical foundations of detection of terahertz radiation in laser-plasma interactions

    SciTech Connect (OSTI)

    Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2013-02-15T23:59:59.000Z

    A theory is developed enabling one to calculate the temporal profile and spectrum of a terahertz wave packet from the energy of the second harmonic of optical radiation generated during the nonlinear interaction between terahertz and circularly polarized laser pulses in the skin layer of an overdense plasma. It is shown that the spectral and temporal characteristics of the envelope of the second harmonic of optical radiation coincide with those of the terahertz pulse only at small durations of the detecting laser radiation. For long laser pulses, the temporal profile and spectrum of the second harmonic are mainly determined by the characteristics of optical radiation at the carrier frequency.

  13. Dual-frequency terahertz emission from splitting filaments induced by lens tilting in air

    SciTech Connect (OSTI)

    Zhang, Zhelin; Chen, Yanping, E-mail: yanping.chen@sjtu.edu.cn; Yang, Liu; Yuan, Xiaohui; Liu, Feng; Chen, Min; Xu, Jianqiu; Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheng, Zhengming [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2014-09-08T23:59:59.000Z

    Dual-frequency terahertz radiation from air-plasma filaments produced with two-color lasers in air has been demonstrated experimentally. When a focusing lens is tilted for a few degrees, it is shown that the laser filament evolves from a single one to two sub-filaments. Two independent terahertz sources emitted from the sub-filaments with different frequencies and polarizations are identified, where the frequency of terahertz waves from the trailing sub-filament is higher than that from the leading sub-filament.

  14. Coherent soliton communication lines

    SciTech Connect (OSTI)

    Yushko, O. V., E-mail: olesya.yushko@gmail.com; Redyuk, A. A.; Fedoruk, M. P.; Turitsyn, S. K. [Novosibirsk State University (Russian Federation)

    2014-11-15T23:59:59.000Z

    The data transmission in coherent fiber-optical communication lines using solitons with a variable phase is studied. It is shown that nonlinear coherent structures (solitons) can be applied for effective signal transmission over a long distance using amplitude and optical-phase keying of information. The optimum ratio of the pulse width to the bit slot at which the spectral efficiency (transmitted bits per second and hertz) is maximal is determined. It is shown that soliton fiber-optical communication lines can ensure data transmission at a higher spectral efficiency as compared to traditional communication lines and at a high signal-to-noise ratio.

  15. Coherence-induced entanglement

    E-Print Network [OSTI]

    Li, F. L.; Xiong, H.; Zubairy, M. Suhail

    2005-01-01T23:59:59.000Z

    . These include correlated spontaneous emission laser #3;2#4;, lasing without in- version #3;3#4;, electromagnetically induced transparence #3;4#4; and spontaneous emission cancellation #3;5#4;. Atomic coherence has recently been shown to play a key role...;9#4;. In this paper we discuss an important application where atomic coherence plays a crucial role in creating entangle- ment between two modes of the electromagnetic field inside a doubly resonant cavity at temperature T, which are coupled to two transitions...

  16. Picosecond dynamics of a silicon donor based terahertz detector device

    SciTech Connect (OSTI)

    Bowyer, Ellis T.; Li, Juerong; Litvinenko, K. L.; Murdin, B. N., E-mail: b.murdin@surrey.ac.uk, E-mail: yuxm@pku.edu.cn [Advanced Technology Institute, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Villis, B. J.; Erfani, Morteza; Matmon, Guy; Aeppli, Gabriel [London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH (United Kingdom); Ortega, Jean-Michel; Prazeres, Rui [Laboratoire de Chemie Physique, Université Paris-Sud 11, 91405 Orsay (France); Dong, Li; Yu, Xiaomei, E-mail: b.murdin@surrey.ac.uk, E-mail: yuxm@pku.edu.cn [Institute of Micro/Nanoelectronics, Peking University, Beijing (China)

    2014-07-14T23:59:59.000Z

    We report the characteristics of a simple complementary metal-oxide-semiconductor compatible terahertz detector device with low response time (nanoseconds) determined using a short-pulse, high intensity free-electron laser. The noise equivalent power was 1?×?10{sup ?11} W Hz{sup ?1/2}. The detector has an enhanced response over narrow bands, most notably at 9.5 THz, with a continuum response at higher frequencies. Using such a device, the dynamics of donors in silicon can be explored, a system which has great potential for quantum information processing.

  17. Graphene-based terahertz photodetector by noise thermometry technique

    SciTech Connect (OSTI)

    Wang, Ming-Jye, E-mail: mingjye@asiss.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Wang, Ji-Wun [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan (China); Wang, Chun-Lun; Chiang, Yen-Yu; Chang, Hsian-Hong [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)

    2014-01-20T23:59:59.000Z

    We report the characteristics of graphene-based terahertz (THz) photodetector based on noise thermometry technique by measuring its noise power at frequency from 4 to 6 GHz. Hot electron system in graphene microbridge is generated after THz photon pumping and creates extra noise power. The equivalent noise temperature and electron temperature increase rapidly in low THz pumping regime and saturate gradually in high THz power regime which is attributed to a faster energy relaxation process involved by stronger electron-phonon interaction. Based on this detector, a conversion efficiency around 0.15 from THz power to noise power in 4–6?GHz span has been achieved.

  18. Tailored Terahertz Pulses from a Laser-Modulated Electron Beam

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructureProposedPAGESafety Tag: Safety DisplayingTailored Terahertz

  19. Tailored Terahertz Pulses from a Laser-Modulated Electron Beam

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesis of 2D Alloys &8-5070P3.Tailored Terahertz

  20. Quantum Coherence Engines

    E-Print Network [OSTI]

    Elias P. Gyftopoulos

    2007-06-20T23:59:59.000Z

    In a report published in Science, Scully et al propose to generate "phaseonium", and "extract work from a single heat bath via vanishing coherence" [1]. On the basis of the laws of physics, such a proposal is futile for at least two reasons.

  1. Coherent hybrid electromagnetic field imaging

    DOE Patents [OSTI]

    Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

    2008-08-26T23:59:59.000Z

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  2. Investigating the effective range of vacuum ultraviolet-mediated breakdown in high-power microwave metamaterials

    SciTech Connect (OSTI)

    Liu, Chien-Hao, E-mail: cliu82@wisc.edu; Neher, Joel D., E-mail: jdneher@wisc.edu; Booske, John H., E-mail: booske@engr.wisc.edu; Behdad, Nader, E-mail: behdad@wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

    2014-10-14T23:59:59.000Z

    Metamaterials and periodic structures operating under high-power excitations are susceptible to breakdown. It was recently demonstrated that a localized breakdown created in a given region of a periodic structure can facilitate breakdown in other regions of the structure where the intensity of the incident electromagnetic fields may not be high enough to cause breakdown under normal circumstances. It was also demonstrated that this phenomenon is due to the generation of vacuum ultraviolet radiation at the location of the initial discharge, which propagates to the neighboring regions (e.g., other unit cells in a periodic structure) and facilitates the generation of a discharge at a lower incident power level. In this paper, we present the results of an experimental study conducted to determine the effective range of this physical phenomenon for periodic structures that operate in air and in pure nitrogen gas at atmospheric pressure levels. It is demonstrated that when breakdown is induced in a periodic structure using a high-power pulse with a frequency of 9.382 GHz, duration of 0.8 ?s, and peak power level of 25 kW, this phenomenon is highly likely to happen in radii of approximately 16–17 mm from the location of the initial discharge under these test conditions. The results of this study are significant in designing metamaterials and periodic structures for high-power microwave applications as they suggest that a localized discharge created in such a periodic structure with a periodicity less than 16–17 mm can spread over a large surface and result in a distributed discharge.

  3. High power Cherenkov radiation from a relativistic particle rotating around a dielectric ball

    E-Print Network [OSTI]

    L. Sh. Grigoryan; H. F. Khachatryan; S. R. Arzumanyan; M. L. Grigoryan

    2005-12-09T23:59:59.000Z

    Some characteristic features in the radiation from a relativistic electron uniformly rotating along an equatorial orbit around a dielectric ball have been studied. It was shown that at some harmonics, in case of weak absorption of radiation in the ball material, the electron may generate radiation field quanta exceeding in several dozens of times those generated by electron rotating in a continuous, infinite and transparent medium having the same real part of permittivity as the ball material. The rise of high power radiation is due to the fact that electromagnetic oscillations of Cherenkov radiation induced along the trajectory of particle are partially locked inside the ball and superimposed in nondestructive way.

  4. The capacitively coupled converter (C³) for high power DC-DC conversion

    E-Print Network [OSTI]

    Khan, Shahriar

    1992-01-01T23:59:59.000Z

    A&M University. A combination of inherent capacitive commutation and gate turn-off switching devices (MCT, GTO, and ZTO) allows zero current switching, and reduces the switching losses to a minimum. This converter is capable of a wide ratio... to implement these switches and the power capability of the transistor can be increased manifold. If a high frequency capability is desired to reduce the sizes of the reactive elements, high power gate turn-off devices, such as the GTO, ZTO, or the MCT may...

  5. Interaction of a High-Power Laser Beam with Metal Sheets

    SciTech Connect (OSTI)

    Boley, C D; Cutter, K P; Fochs, S N; Pax, P H; Rotter, M D; Rubenchik, A M; Yamamoto, R M

    2009-06-24T23:59:59.000Z

    Experiments with a high-power laser beam directed onto thin aluminum sheets, with a large spot size, demonstrate that airflow produces a strong enhancement of the interaction. The enhancement is explained in terms of aerodynamic effects. As laser heating softens the material, the airflow-induced pressure difference between front and rear faces causes the metal to bulge into the beam. The resulting shear stresses rupture the material and remove it at temperatures well below the melting point. The material heating is shown to conform to an elementary model. We present an analytic model of elastic bulging. Scaling with respect to spot size, wind speed, and material parameters is determined.

  6. High Power, High Voltage FETs in Linear Applications: A User's Perspective

    SciTech Connect (OSTI)

    N. Greenough, E. Fredd, S. DePasquale

    2009-09-21T23:59:59.000Z

    The specifications of the current crop of highpower, high-voltage field-effect transistors (FETs) can lure a designer into employing them in high-voltage DC equipment. Devices with extremely low on-resistance and very high power ratings are available from several manufacturers. However, our experience shows that high-voltage, linear operation of these devices at near-continuous duty can present difficult reliability challenges at stress levels well-below their published specifications. This paper chronicles the design evolution of a 600 volt, 8 ampere shunt regulator for use with megawatt-class radio transmitters, and presents a final design that has met its reliability criteria.

  7. Improved Structure and Fabrication of Large, High-Power KHPS Rotors - Final Scientific/Technical Report

    SciTech Connect (OSTI)

    Corren, Dean [Verdant Power, Inc.; Colby, Jonathan [Verdant Power, Inc.; Adonizio, Mary Ann [Verdant Power, Inc.

    2013-01-29T23:59:59.000Z

    Verdant Power, Inc, working in partnership with the National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), and the University of Minnesota St. Anthony Falls Laboratory (SAFL), among other partners, used evolving Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) models and techniques to improve the structure and fabrication of large, high-power composite Kinetic Hydropower System (KHPS) rotor blades. The objectives of the project were to: design; analyze; develop for manufacture and fabricate; and thoroughly test, in the lab and at full scale in the water, the improved KHPS rotor blade.

  8. Spectroscopic imaging of self-organization in high power impulse magnetron sputtering plasmas

    SciTech Connect (OSTI)

    Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore; Andersson, Joakim; Ni, Pavel; Anders, Andre

    2013-07-17T23:59:59.000Z

    Excitation and ionization conditions in traveling ionization zones of high power impulse magnetron sputtering plasmas were investigated using fast camera imaging through interference filters. The images, taken in end-on and side on views using light of selected gas and target atom and ion spectral lines, suggest that ionization zones are regions of enhanced densities of electrons, and excited atoms and ions. Excited atoms and ions of the target material (Al) are strongly concentrated near the target surface. Images from the highest excitation energies exhibit the most localized regions, suggesting localized Ohmic heating consistent with double layer formation.

  9. Engineering development of superconducting RF linac for high-power applications

    SciTech Connect (OSTI)

    Dominic Chan, K.C.; Rusnak, B.; Gentzlinger, R.C.; Campbell, B.M.; Kelley, J.P. [Los Alamos National Lab., NM (United States); Safa, H. [CEA Saclay (France)

    1998-12-31T23:59:59.000Z

    High-power proton linacs are a promising source of neutrons for material processing and research applications. Superconducting radiofrequency (SCRF) Rf linac technology is preferred for such applications because of power efficiency. A multi-year engineering development program is underway at Los Alamos National Laboratory to demonstrate the required SCRF technology. The program consists of development of SC cavities, power couplers, and cryomodule integration. Prototypes will be built and operated to obtain performance and integration information, and for design improvement. This paper describes the scope and present status of the development program.

  10. High power tests of dressed supconducting 1.3 GHz RF cavities

    SciTech Connect (OSTI)

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

    2011-03-01T23:59:59.000Z

    A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted ('dressed') with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.

  11. Surface treated natural graphite as anode material for high-power Li-ion battery applications.

    SciTech Connect (OSTI)

    Liu, J.; Vissers, D. R.; Amine, K.; Barsukov, I. V.; Henry, F.; Doniger, J.; Chemical Engineering; Superior Graphite Co.

    2006-01-01T23:59:59.000Z

    High power application of Li-ion battery in hybrid electrical vehicles requires low cost and safe cell materials. Among the various carbon anode materials used in lithium ion batteries, natural graphite shows the most promise with advantages in performance and cost. However, natural graphite is not compatible with propylene carbonate (PC)-based electrolytes, which have a lower melting point and improved safety characteristics. The problem with it is that the molecules of propylene carbonate intercalate with Li+ into graphite, and that frequently leads to the exfoliation of the graphite matrix.

  12. Photoconductivity of graphene devices induced by terahertz radiation at various photon energies

    SciTech Connect (OSTI)

    Salman, M.; Nachtwei, G. [NTH School for Contacts in Nanosystems, Germany and Institut fuer Angewandte Physik, Technische Universitaet Braunschweig, D-38106 Braunschweig (Germany); Gouider, F.; Göthlich, M. [Institut fuer Angewandte Physik, Technische Universitaet Braunschweig, D-38106 Braunschweig (Germany); Friedemann, M.; Ahlers, F. J. [Physikalisch Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany); Schmidt, H.; Haug, R. J. [NTH School for Contacts in Nanosystems, Germany and Institut fuer Festkoerperphysik, Universitaet Hannover, D-30167 Hannover (Germany)

    2013-12-04T23:59:59.000Z

    The influence of a magnetic field on Landau levels (LLs) in graphene-based devices is described via the magneto-optical response induced by terahertz (THz) radiation. For single-layer graphene, the resonance energies of the transitions between the on Landau levels (LLs) such as L{sub 1}, L{sub 2} and L{sub 3} fit quite well to the terahertz spectral range at low magnetic fields. Also, the calculations for the terahertz photoresponse (photoconductivity) in the presence of low magnetic fields, the reported calculations for the scattering rate of LLs, recent and our experimental results of photoresponse measurements yield that single-layer graphene is suitable for the detection of terahertz radiation.

  13. A terahertz pulse emitter monolithically integrated with a quantum cascade laser

    E-Print Network [OSTI]

    Kao, Tsung-Yu

    A terahertz pulse emitter monolithically integrated with a quantum cascade laser(QCL) is demonstrated. The emitter facet is excited by near-infrared pulses from a mode-locked Ti:sapphire laser, and the resulting current ...

  14. Nonlinear terahertz spectroscopy of electronic and vibrational responses in condensed matter systems

    E-Print Network [OSTI]

    Hwang, Harold Young

    2012-01-01T23:59:59.000Z

    In this work, I describe experiments utilizing high-field terahertz (THz) pulses to initiate nonlinear responses in several classes of materials. We have developed several methods for interrogating the nonlinear THz response ...

  15. Maximally coherent mixed states: Complementarity between maximal coherence and mixedness

    E-Print Network [OSTI]

    Uttam Singh; Manabendra Nath Bera; Himadri Shekhar Dhar; Arun Kumar Pati

    2015-03-21T23:59:59.000Z

    Quantum coherence is a key component of topical research on quantum resource theories and a primary facilitator for design and implementation of quantum technologies. However, the resourcefulness of quantum coherence is severely restricted by environmental noise, which is indicated by the loss of information in a quantum system, measured in terms of its purity. In this work, we derive the limits imposed by the mixedness of a quantum system on the amount of quantum coherence that it can possess. We obtain an analytical trade-off between the two quantities that upperbounds the maximum quantum coherence for fixed mixedness in a system. This gives rise to a class of quantum states, "maximally coherent mixed states", whose coherence cannot be increased further under any purity-preserving operation. For the above class of states, quantum coherence and mixedness satisfy a complementarity relation, which is crucial to understand the interplay between a resource and noise in open quantum systems.

  16. Helicity sensitive terahertz radiation detection by field effect transistors C. Drexler, N. Dyakonova, P. Olbrich, J. Karch, M. Schafberger et al.

    E-Print Network [OSTI]

    Levelut, Claire

    Helicity sensitive terahertz radiation detection by field effect transistors C. Drexler, N sensitive terahertz radiation detection by field effect transistors C. Drexler,1 N. Dyakonova,2 P. Olbrich,1

  17. Pulse shortening, spatial mode cleaning, and intense terahertz generation by filamentation in xenon

    SciTech Connect (OSTI)

    Akturk, Selcuk; D'Amico, Ciro; Franco, Michel; Couairon, Arnaud; Mysyrowicz, Andre [Laboratoire d'Optique Appliquee, Ecole Nationale Superieure des Techniques Avancees-Ecole Polytechnique, CNRS UMR 7639 F-91761 Palaiseau Cedex, France and Centre de Physique Theorique, CNRS UMR 7644, Ecole Polytechnique, F-91128 Palaiseau Cedex (France)

    2007-12-15T23:59:59.000Z

    We performed a comprehensive study of filamentation in xenon. Due to its high nonlinear refraction index, but relatively low ionization potential, xenon can support filamentation at peak powers lower than in air. In our experiments, we studied pulse shortening, spatial mode cleaning, and generation of terahertz radiation. We observed that in xenon, self-compression is easily obtainable and terahertz radiation generation efficiency is significantly stronger as compared to air.

  18. Room temperature broadband terahertz gains in graphene heterostructures based on inter-layer radiative transitions

    SciTech Connect (OSTI)

    Tang, Linlong [Key Laboratory of High Energy Density Physics and Technology, College of Physics and Technology, Sichuan University, Chengdu, 610064 (China); Chongqing institute of green and intelligent technology, Chinese Academy of Sciences, Chongqing, 401122 (China); Du, Jinglei, E-mail: dujl@scu.edu.cn [Key Laboratory of High Energy Density Physics and Technology, College of Physics and Technology, Sichuan University, Chengdu, 610064 (China); Shi, Haofei, E-mail: shi@cigit.ac.cn; Wei, Dongshan; Du, Chunlei, E-mail: cldu@cigit.ac.cn [Chongqing institute of green and intelligent technology, Chinese Academy of Sciences, Chongqing, 401122 (China)

    2014-10-15T23:59:59.000Z

    We exploit inter-layer radiative transitions to provide gains to amplify terahertz waves in graphene heterostructures. This is achieved by properly doping graphene sheets and aligning their energy bands so that the processes of stimulated emissions can overwhelm absorptions. We derive an expression for the gain estimation and show the gain is insensitive to temperature variation. Moreover, the gain is broadband and can be strong enough to compensate the free carrier loss, indicating graphene based room temperature terahertz lasers are feasible.

  19. Electro-optic crystal mosaics for the generation of terahertz radiation

    DOE Patents [OSTI]

    Carrig, Timothy J. (Los Alamos, NM); Taylor, Antoinette J. (Los Alamos, NM); Stewart, Kevin R. (Schenectady, NY)

    1996-01-01T23:59:59.000Z

    Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification.

  20. FERROELECTRIC SWITCH FOR A HIGH-POWER Ka-BAND ACTIVE PULSE COMPRESSOR

    SciTech Connect (OSTI)

    Hirshfield, Jay L. [Omega-P, Inc.] [Omega-P, Inc.

    2013-12-18T23:59:59.000Z

    Results are presented for design of a high-power microwave switch for operation at 34.3 GHz, intended for use in an active RF pulse compressor. The active element in the switch is a ring of ferroelectric material, whose dielectric constant can be rapidly changed by application of a high-voltage pulse. As envisioned, two of these switches would be built into a pair of delay lines, as in SLED-II at SLAC, so as to allow 30-MW ?s-length Ka-band pulses to be compressed in time by a factor-of-9 and multiplied in amplitude to generate 200 MW peak power pulses. Such high-power pulses could be used for testing and evaluation of high-gradient mm-wave accelerator structures, for example. Evaluation of the switch design was carried out with an X-band (11.43 GHz) prototype, built to incorporate all the features required for the Ka-band version.

  1. System efficiency analysis for high power solid state radio frequency transmitter

    SciTech Connect (OSTI)

    Jain, Akhilesh, E-mail: ajain@rrcat.gov.in; Sharma, D. K.; Gupta, A. K.; Lad, M. R.; Hannurkar, P. R. [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Pathak, S. K. [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)] [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)

    2014-02-15T23:59:59.000Z

    This paper examines some important relationships, related with the system efficiency, for very high power, radio frequency solid-state transmitter; incorporating multiple solid-state power amplifier modules, power combiners, dividers, couplers, and control/interlock hardware. In particular, the characterization of such transmitters, at the component as well as the system level, is discussed. The analysis for studying the influence of the amplitude and phase imbalance, on useful performance parameters like system efficiency and power distribution is performed. This analysis is based on a scattering parameter model. This model serves as a template for fine-tuning the results, with the help of a system level simulator. For experimental study, this approach is applied to a recently designed modular and scalable solid-state transmitter, operating at the centre frequency of 505.8?MHz and capable of delivering a continuous power of 75 kW. Such first time presented, system level study and experimental characterization for the real time operation will be useful for the high power solid-state amplifier designs, deployed in particle accelerators.

  2. Failure modes in high-power lithium-ion batteries for use inhybrid electric vehicles

    SciTech Connect (OSTI)

    Kostecki, R.; Zhang, X.; Ross Jr., P.N.; Kong, F.; Sloop, S.; Kerr, J.B.; Striebel, K.; Cairns, E.; McLarnon, F.

    2001-06-22T23:59:59.000Z

    The Advanced Technology Development (ATD) Program seeks to aid the development of high-power lithium-ion batteries for hybrid electric vehicles. Nine 18650-size ATD baseline cells were tested under a variety of conditions. The cells consisted of a carbon anode, LiNi{sub 0.8}Co{sub 0.2}O{sub 2} cathode and DEC-EC-LiPF{sub 6} electrolyte, and they were engineered for high-power applications. Selected instrumental techniques such as synchrotron IR microscopy, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, gas chromatography, etc. were used to characterize the anode, cathode, current collectors and electrolyte from these cells. The goal was to identify detrimental processes which lead to battery failure under a high-current cycling regime as well as during storage at elevated temperatures. The diagnostic results suggest that the following factors contribute to the cell power loss: (a) SEI deterioration and non-uniformity on the anode, (b) morphology changes, increase of impedance and phase separation on the cathode, (c) pitting corrosion on the cathode Al current collector, and (d) decomposition of the LiPF{sub 6} salt in the electrolyte at elevated temperature.

  3. High-power LEDs based on InGaAsP/InP heterostructures

    SciTech Connect (OSTI)

    Rakovics, V. [Hungarian Academy of Sciences, Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences (Hungary); Imenkov, A. N.; Sherstnev, V. V.; Serebrennikova, O. Yu.; Il’inskaya, N. D.; Yakovlev, Yu. P., E-mail: Yak@iropt1.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2014-12-15T23:59:59.000Z

    High-power light-emitting diodes (LEDs) with mesa diameters of 100, 200, and 300 ?m are developed on the basis of InGaAsP/InP heterostructures. The mesas are close in shape to a truncated cone with a generatrix inclination angle of ?45° in the vicinity of the active region of the LED, with a ring etched around the mesa serving as a reflector. The emission spectra and directivity patterns of these LEDs are studied in a wide range of current densities and it is shown that radiative recombination is dominant to a current density of ?5000 A/cm{sup 2}, which makes these structures promising for the development of high-power LEDs. An emission power of ?14 mW is obtained in the continuous-wave mode (I = 0.2 A, ? = 1.1 ?m), and that of 77 mW, in the pulsed mode (I = 2 A, ? = 1.1 ?m), which corresponds to external quantum efficiencies of 6.2 and 3.4%, respectively.

  4. Demonstration of novel high-power acoustic through-the-wall sensor

    E-Print Network [OSTI]

    Felber, Franklin

    2015-01-01T23:59:59.000Z

    A high-power acoustic sensor, capable of detecting and tracking persons through steel walls of cargo containers, trailer truck bodies, and train cars, has been developed and demonstrated. The sensor is based on a new concept for narrowband mechanical-impact acoustic transmitters and matched resonant receivers. The lightweight, compact, and low-cost transmitters produce high-power acoustic pulses at one or more discrete frequencies with little input power. The energy for each pulse is accumulated over long times at low powers, like a mousetrap, and therefore can be operated with ordinary batteries and no power conditioning. A breadboard impact-transmitter and matched-receiver system that detected human motion through thick walls with only rudimentary signal processing is described, and results are presented. A conceptual design is presented of an acoustic through-the-wall sensor, costing about $10,000 per unit and capable of remotely and non-intrusively scanning steel cargo containers for stowaways at a rate o...

  5. Development of a frequency doubled high powered laser diode end-pumped Nd:YVO?/LBO laser 

    E-Print Network [OSTI]

    Barr, Aaron Maxwell

    2003-01-01T23:59:59.000Z

    The development of a high power solid state laser poses a serious non-trivial task. Several different elements combine to form this complex quantum device. Each of the elements of the laser receives sufficient description herein. The pump source...

  6. Optimization of Acetylene Black Conductive Additive and Polyvinylidene Difluoride Composition for High Power Rechargeable Lithium-Ion Cells

    E-Print Network [OSTI]

    Liu, G.; Zheng, H.; Battaglia, V.S.; Simens, A.S.; Minor, A.M.; Song, X.

    2007-01-01T23:59:59.000Z

    7), A365 G. M. Ehrlich, Lithium-ion Batteries, 3rd ed ed. (High Power Rechargeable Lithium-Ion Cells G. Liu a,z , H.local environment. (A) lithium-ion mass transfer in the

  7. Diagnostic evaluation of power fade phenomena and calendar life reduction in high-power lithium-ion batteries

    E-Print Network [OSTI]

    Kostecki, Robert; McLarnon, Frank

    2004-01-01T23:59:59.000Z

    HIGH-POWER LITHIUM-ION BATTERIES Robert Kostecki and FrankAFM Introduction Lithium-ion batteries are being seriously1.2 M LiPF 6 /graphite batteries for hybrid electric vehicle

  8. Technology survey and performance scaling for the design of high power nuclear electric power and propulsion systems

    E-Print Network [OSTI]

    White, Daniel B., Jr

    2011-01-01T23:59:59.000Z

    High power nuclear electric propulsion systems have the capability to enable many next-generation space exploration applications. To date, use of electric primary propulsion in flight systems has been limited to low-power, ...

  9. Development of a frequency doubled high powered laser diode end-pumped Nd:YVO?/LBO laser

    E-Print Network [OSTI]

    Barr, Aaron Maxwell

    2003-01-01T23:59:59.000Z

    The development of a high power solid state laser poses a serious non-trivial task. Several different elements combine to form this complex quantum device. Each of the elements of the laser receives sufficient description herein. The pump source...

  10. High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium-doped PPKTP

    E-Print Network [OSTI]

    Boyer, Edmond

    , T. Kozaki, T. Yanamoto, S. Nagahama, and T. Mukai, "High-Power Pure Blue InGaN Laser Diodes there is substantial absorption in KTP which leads to temporal instabilities at highest power levels, but stable output

  11. X-ray photoelectron spectroscopy of negative electrodes from high-power lithium-ion cells showing various levels of power fade

    E-Print Network [OSTI]

    Herstedt, Marie; Abraham, Daniel P.; Kerr, John B.

    2004-01-01T23:59:59.000Z

    Electrodes from High-Power Lithium-Ion Cells Showing VariousAbstract High-power lithium-ion cells for transportationknown electrolytes during lithium ion intercalation this SEI

  12. Low-spatial coherence electrically-pumped semiconductor laser for speckle-free full-field imaging

    E-Print Network [OSTI]

    Redding, B; Huang, X; Lee, M L; Stone, A D; Choma, M A; Cao, H

    2014-01-01T23:59:59.000Z

    The spatial coherence of laser sources has limited their application to parallel imaging and projection due to coherent artifacts, such as speckle. In contrast, traditional incoherent light sources, such as thermal sources or light emitting diodes (LEDs), provide relatively low power per independent spatial mode. Here, we present a chip-scale, electrically-pumped semiconductor laser based on a novel design, demonstrating high power per mode with much lower spatial coherence than conventional laser sources. The laser resonator was fabricated with a chaotic, D-shaped cavity optimized to achieve highly multimode lasing. Lasing occurs simultaneously and independently in ~1000 modes, and hence the total emission exhibits very low spatial coherence. Speckle-free full-field imaging is demonstrated using the chaotic cavity laser as the illumination source. The power per mode of the sample illumination is several orders of magnitude higher than that of a LED or thermal light source. Such a compact, low-cost source, wh...

  13. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 51, NO. 12, DECEMBER 2003 2469 Broad-Band High-Power Amplifier Using Spatial

    E-Print Network [OSTI]

    York, Robert A.

    --High power, broad bandwidth, high linearity, and low noise are among the most important features in amplifier-power application. A high-power amplifier using the compact combiner design is built and demonstrated to have-Band High-Power Amplifier Using Spatial Power-Combining Technique Pengcheng Jia, Member, IEEE, Lee-Yin Chen

  14. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

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

    Anders, Andre

    2014-10-01T23:59:59.000Z

    High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

  15. Commissioning the new high power rf system for the AGS with high intensity beam

    SciTech Connect (OSTI)

    Brennan, J.M.; Ciardullo, D.J.; Deng, D.P; Hayes, T.; Onillon, E.; Otis, A.; Sanders, R.T.; Zaltsman, A.

    1994-08-01T23:59:59.000Z

    A new high power rf system has been installed in the AGS in order to raise the beam loading limit to beyond 6 {times} 10{sup 13} protons per pulse. The old system was limited to 2.2 {times} 10{sup l3} ppp by: available real power, multi-loop instability, and transient beam loading during batch filling from the Booster. The key components of the new system are: new power amplifiers in the tunnel using the Thomson-CSF TH573 300kW tetrode, rf feedback around the power stage, and reduction of the 10 cavities` R/Q by 1.8 by additional gap capacitors. Commissioning of the new rf system with high intensity beam is described. The intensity goal for the 1994 running period is 4 {times} 10{sup 13} ppp. To date, 3.7 {times} 10{sup 13} ppp has been achieved.

  16. Philips Lumileds Develops a Low-Cost, High-Power, Warm-White LED Package

    Broader source: Energy.gov [DOE]

    With the help of DOE funding, Philips Lumileds has developed a low-cost, high-power, warm-white LED package for general illumination. During the course of the two-year project, this package was used to commercialize a series of products with correlated color temperatures (CCTs) ranging from 2700 to 5700 K, under the product name LUXEON M. A record efficacy of nearly 125 lm/W was demonstrated at a flux of 1023 lumens, a CCT of 3435 K, and a color rendering index (CRI) of more than 80 at room temperature in the productized package. In an R&D package, a record efficacy of more than 133 lm/W at a flux of 1015 lumens, a CCT of 3475 K, and a CRI greater than 80 at room temperature were demonstrated.

  17. Stimulated Raman Scattering and Nonlinear Focusing of High-Power Laser Beams Propagating in Water

    E-Print Network [OSTI]

    Hafizi, B; Penano, J R; Gordon, D F; Jones, T G; Helle, M H; Kaganovich, D

    2015-01-01T23:59:59.000Z

    The physical processes associated with propagation of a high-power (power > critical power for self-focusing) laser beam in water include nonlinear focusing, stimulated Raman scattering (SRS), optical breakdown and plasma formation. The interplay between nonlinear focusing and SRS is analyzed for cases where a significant portion of the pump power is channeled into the Stokes wave. Propagation simulations and an analytical model demonstrate that the Stokes wave can re-focus the pump wave after the power in the latter falls below the critical power. It is shown that this novel focusing mechanism is distinct from cross-phase focusing. While discussed here in the context of propagation in water, the gain-focusing phenomenon is general to any medium supporting nonlinear focusing and stimulated forward Raman scattering.

  18. Method of Fabrication of High Power Density Solid Oxide Fuel Cells

    DOE Patents [OSTI]

    Pham, Ai Quoc (San Jose, CA); Glass, Robert S. (Livermore, CA)

    2008-09-09T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O(LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  19. Interfacial electron and phonon scattering processes in high-powered nanoscale applications.

    SciTech Connect (OSTI)

    Hopkins, Patrick E.

    2011-10-01T23:59:59.000Z

    The overarching goal of this Truman LDRD project was to explore mechanisms of thermal transport at interfaces of nanomaterials, specifically linking the thermal conductivity and thermal boundary conductance to the structures and geometries of interfaces and boundaries. Deposition, fabrication, and post possessing procedures of nanocomposites and devices can give rise to interatomic mixing around interfaces of materials leading to stresses and imperfections that could affect heat transfer. An understanding of the physics of energy carrier scattering processes and their response to interfacial disorder will elucidate the potentials of applying these novel materials to next-generation high powered nanodevices and energy conversion applications. An additional goal of this project was to use the knowledge gained from linking interfacial structure to thermal transport in order to develop avenues to control, or 'tune' the thermal transport in nanosystems.

  20. Target isolation system, high power laser and laser peening method and system using same

    DOE Patents [OSTI]

    Dane, C. Brent (Livermore, CA); Hackel, Lloyd A. (Livermore, CA); Harris, Fritz (Rocklin, CA)

    2007-11-06T23:59:59.000Z

    A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

  1. Overview Of Control System For Jefferson Lab`s High Power Free Electron Laser

    SciTech Connect (OSTI)

    Hofler, A. S.; Grippo, A. C.; Keesee, M. S.; Song, J.

    1997-12-31T23:59:59.000Z

    In this paper the current plans for the control system for Thomas Jefferson National Accelerator Facility`s (Jefferson Lab`s) Infrared Free Electron Laser (FEL) are presented. The goals for the FEL control system are fourfold: (1) to use EPICS and EPICS compatible tools, (2) to use VME and Industry Pack (IPs) interfaces for FEL specific devices such as controls and diagnostics for the drive laser, high power optics, photocathode gun and electron-beam diagnostics, (3) to migrate Continuous Electron Beam Accelerator Facility (CEBAF) technologies to VME when possible, and (4) to use CAMAC solutions for systems that duplicate CEBAF technologies such as RF linacs and DC magnets. This paper will describe the software developed for FEL specific devices and provide an overview of the FEL control system.

  2. High power water load for microwave and millimeter-wave radio frequency sources

    DOE Patents [OSTI]

    Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

    1999-01-01T23:59:59.000Z

    A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

  3. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

    SciTech Connect (OSTI)

    Anders, Andre

    2014-08-17T23:59:59.000Z

    High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

  4. Application of high powered lasers to drilling and completing deep walls.

    SciTech Connect (OSTI)

    Reed, C. B.; Xu, Z.; Parker, R. A.; Gahan, B. C.; Batarseh, S.; Graves, R. M.; Figueroa, H.; Deeg, W.

    2003-07-30T23:59:59.000Z

    High powered laser rock drilling was studied as a revolutionary method for drilling and completing deep gas and oil wells. The objectives of this 2002 to 2003 fiscal year research were to study the concept that large diameter holes can be created by multiple overlapping small beam spots, to determine the ability of lasers to drill rock submerged to some depth in water, to demonstrate the possibilities of lasers for perforating application, and to determine the wavelength effects on rock removal. Laser technology applied to well drilling and completion operations is attractive because it has the potential to reduce drilling time, create a ceramic lining that may eliminate the need for steel casing, provide additional monitor-on-drilling laser sensors and improve well performance through improved perforation. The results from this research will help engineering design on a laser-based well drilling system.

  5. High power 325 MHz vector modulators for the Fermilab High Intensity Neutrino Source (HINS)

    SciTech Connect (OSTI)

    Madrak, Robyn Leigh; Wildman, David; /Fermilab

    2008-10-01T23:59:59.000Z

    One of the goals of the low energy 60 MeV section of the HINS H{sup -} linac [1] is to demonstrate that a total of {approx}40 RF cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each RF cavity to independently adjust the amplitude and phase of the RF input signal during the 3.5 ms RF pulse. Two versions of vector modulators have been developed; a 500 kW device for the radiofrequency quadrupole (RFQ) and a 75 kW modulator for the RF cavities. High power tests showing the vector modulator phase and amplitude responses will be presented.

  6. LEDA - A HIGH-POWER TEST BED OF INNOVATION AND OPPORTUNITY

    SciTech Connect (OSTI)

    J. SCHNEIDER; R. SHEFFIELD

    2000-08-01T23:59:59.000Z

    The low-energy demonstration accelerator (LEDA) is an operational 6.7-MeV. 100-mA proton accelerator consisting of an injector, radio-frequency quadrupole (RFQ), and all associated integration equipment. In order to achieve this unprecedented level of performance (670-kW of beam power) from an RFQ, a number of design innovations were required. They will highlight a number of those more significant technical advances, including those in the proton injector, the RFQ configuration, the RF klystrons, the beam stop, and the challenges of beam measurements. In addition to identifying the importance of these innovations to LEDA performance, they will summarize the plans for further testing, and the possibilities for addition of more accelerating structures, including the planned use of very-low-beta super-conducting structures. LEDA's current and upgradable configuration is appropriate for several future high-power accelerators, including those for the transmutation of radioactive waste.

  7. A compact ultranarrow high-power laser system for experiments with 578nm Ytterbium clock transition

    E-Print Network [OSTI]

    Cappellini, Giacomo; Mancini, Marco; Pagano, Guido; Pizzocaro, Marco; Fallani, Leonardo; Catani, Jacopo

    2015-01-01T23:59:59.000Z

    In this paper we present the realization of a compact, high-power laser system able to excite the Ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to a ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic $^{173}$Yb with a < 50 Hz linewidth over 5 minutes, limited only by a residual frequency drift of some 0.1 Hz/s.

  8. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

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

    Anders, Andre

    2014-10-01T23:59:59.000Z

    High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overviewmore »is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.« less

  9. High-Power Solid-State Lasers from a Laser Glass Perspective

    SciTech Connect (OSTI)

    Campbell, J H; Hayden, J S; Marker, A J

    2010-12-17T23:59:59.000Z

    Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

  10. An innovative demonstration of high power density in a compact MHD (magnetohydrodynamic) generator

    SciTech Connect (OSTI)

    Schmidt, H.J.; Lineberry, J.T.; Chapman, J.N.

    1990-06-01T23:59:59.000Z

    The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible. 4 refs., 60 figs., 9 tabs.

  11. Niobium direct detectors for fast and sensitive terahertz spectroscopy M. O. Reese, D. F. Santavicca, and D. E. Prober

    E-Print Network [OSTI]

    Niobium direct detectors for fast and sensitive terahertz spectroscopy M. O. Reese, D. F the performance of a niobium hot-electron bolometer designed for laboratory terahertz spectroscopy. The antenna of a niobium Nb hot-electron detector that addresses these needs. The detector is an antenna-coupled bolometer

  12. All-electric detection of the polarization state of terahertz laser radiation S. D. Ganichev,1,a

    E-Print Network [OSTI]

    Ganichev, Sergey

    All-electric detection of the polarization state of terahertz laser radiation S. D. Ganichev,1,a W online 6 June 2008 Two types of room-temperature detectors of terahertz laser radiation have been developed which allow, in an all-electric manner, the determination of the plane of polarization of linearly

  13. Terahertz radiation and second-harmonic generation from InAs: Bulk versus surface electric-field-induced contributions

    E-Print Network [OSTI]

    Reid, Matthew

    time due to a growing number of applications such as imaging,1­3 illicit-drug detection,4Terahertz radiation and second-harmonic generation from InAs: Bulk versus surface electric July 2005 Polarized second-harmonic generation and terahertz radiation in reflection from 100 , 110

  14. Terahertz studies of carrier dynamics and dielectric response of n-type, freestanding epitaxial GaN

    E-Print Network [OSTI]

    Terahertz studies of carrier dynamics and dielectric response of n-type, freestanding epitaxial GaN conductivity and dielectric function of GaN by terahertz time-domain spectroscopy. Transmission measurements are performed on an n-type, 180- m-thick, freestanding GaN crystal. Frequency dependent electron dynamics, power

  15. High-Q terahertz metamaterial from superconducting niobium nitride films

    E-Print Network [OSTI]

    Zhang, C H; Jin, B B; Ji, Z M; Kang, L; Xu, W W; Chen, J; Wu, P H

    2011-01-01T23:59:59.000Z

    We present in this letter terahertz (THz) metamaterials with low ohmic losses made from low-temperature superconductor niobium nitride (NbN) films. The resonance properties are characterized by THz time-domain spectroscopy. The unloaded quality factor reaches as high as about 178 at 8 K with the resonance frequency at around 0.58 THz, which is about 24 times as many as gold metamaterials with the same structure. The unloaded quality factor also keeps high as the resonance frequency increases, which is about 90 at 1.02 THz that is close the gap frequency of NbN film. All these experimental observations are well understood in the framework of Bardeen-Cooper-Schrieffer theory and equivalent circuit model. Our work offers an efficient way to design and make high-performance THz electronic devices.

  16. Dark current mechanism of terahertz quantum-well photodetectors

    SciTech Connect (OSTI)

    Jia, J. Y.; Gao, J. H.; Hao, M. R.; Wang, T. M.; Shen, W. Z.; Zhang, Y. H., E-mail: yuehzhang@sjtu.edu.cn [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, J. C.; Guo, X. G. [Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Schneider, H., E-mail: h.schneider@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, P.O. Box 510119, 01314 Dresden (Germany)

    2014-10-21T23:59:59.000Z

    Dark current mechanisms of terahertz quantum-well photodetectors (THz QWPs) are systematically investigated experimentally and theoretically by measuring two newly designed structures combined with samples reported previously. In contrast to previous investigations, scattering-assisted tunneling dark current is found to cause significant contributions to total dark current. A criterion is also proposed to determine the major dark current mechanism at different peak response frequencies. We further determine background limited performance (BLIP) temperatures, which decrease both experimentally and theoretically as the electric field increases. This work gives good description of dark current mechanism for QWPs in the THz region and is extended to determine the transition fields and BLIP temperatures with response peaks from 3 to 12 THz.

  17. Terahertz Radiation from a Pipe with Small Corrugations

    SciTech Connect (OSTI)

    Bane, K.L.F.; Stupakov, G.; /SLAC

    2012-01-26T23:59:59.000Z

    We have studied through analytical and numerical methods the use of a relativistic electron bunch to drive a metallic beam pipe with small corrugations for the purpose of generating terahertz radiation. For the case of a pipe with dimensions that do not change along its length, we have shown that - with reasonable parameters - one can generate a narrow-band radiation pulse with frequency {approx}1 THz, and total energy of a few milli-Joules. The pulse length tends to be on the order of tens of picoseconds. We have also shown that, if the pipe radius is tapered along its length, the generated pulse will end up with a frequency chirp; if the pulse is then made to pass through a compressor, its final length can be reduced to a few picoseconds and its peak power increased to 1 GW. We have also shown that wall losses tend to be significant and need to be included in the structure design.

  18. Linac Coherent Light Source Overview

    Broader source: Energy.gov [DOE]

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  19. Linac Coherent Light Source Overview

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  20. Linac Coherent Light Source Overview

    ScienceCinema (OSTI)

    None

    2013-05-29T23:59:59.000Z

    Take an animated tour of the Linac Coherent Light Source (LCLS). Follow the laser pulse from the injector gun all the way through to the Far Experimental Hall.

  1. Coherent states on the circle

    E-Print Network [OSTI]

    Chadzitaskos, G; Tolar, J

    2011-01-01T23:59:59.000Z

    We present a possible construction of coherent states on the unit circle as configuration space. In our approach the phase space is the product Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization over a finite periodic chain where the phase space was Z_M x Z_M. Properties of the coherent states constructed in this way are studied and the coherent states are shown to satisfy the resolution of unity.

  2. Development and Implementation of a VHF High Power Amplifier for the Multi-Channel Coherent Radar Depth Sounder/Imager System

    E-Print Network [OSTI]

    Crowe, Reid William

    2013-08-31T23:59:59.000Z

    ............................................................................. 106 Appendix B findFrequency MATLAB Function ....................................................................... 112 Appendix C WF_First_Run MATLAB Function ........................................................................ 113 Appendix D... Vs. frequency of the driver amplifier stage operating in pulse mode for an input drive level of -8.4 dBm ............................................................................ 53 vii Figure 5.9: Measured Gain Vs. Frequency of the high...

  3. APEX and ALPS, high power density technology programs in the U.S.

    SciTech Connect (OSTI)

    Wong, C. [General Atomics, San Diego, CA (United States). Fusion Group; Berk, S. [Dept. of Energy, Washington, DC (United States). Office of Fusion Energy Sciences; Abdou, M. [Univ. of California, Los Angeles, CA (United States). School of Engineering and Applied Science; Mattas, R. [Argonne National Lab., IL (United States). Fusion Power Program

    1999-02-01T23:59:59.000Z

    In fiscal year (FY) 1998 two new fusion technology programs were initiated in the US, with the goal of making marked progress in the scientific understanding of technologies and materials required to withstand high plasma heat flux and neutron wall loads. APEX is exploring new and revolutionary concepts that can provide the capability to extract heat efficiently from a system with high neutron and surface heat loads while satisfying all the fusion power technology requirements and achieving maximum reliability, maintainability, safety, and environmental acceptability. ALPS program is evaluating advanced concepts including liquid surface limiters and divertors on the basis of such factors as their compatibility with fusion plasma, high power density handling capabilities, engineering feasibility, lifetime, safety and R and D requirements. The APEX and ALPS are three-year programs to specify requirements and evaluate criteria for revolutionary approaches in first wall, blanket and high heat flux component applications. Conceptual design and analysis of candidate concepts are being performed with the goal of selecting the most promising first wall, blanket and high heat flux component designs that will provide the technical basis for the initiation of a significant R and D effort beginning in FY2001. These programs are also considering opportunities for international collaborations.

  4. Gas breakdown driven by L band short-pulse high-power microwave

    SciTech Connect (OSTI)

    Yang Yiming; Yuan Chengwei; Qian Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2012-12-15T23:59:59.000Z

    High power microwave (HPM) driven gas breakdown is a major factor in limiting the radiation and transmission of HPM. A method that HPM driven gas breakdown could be obtained by changing the aperture of horn antenna is studied in this paper. Changing the effective aperture of horn antenna can adjust the electric field in near field zone, leading to gas breakdown. With this method, measurements of air and SF{sub 6} breakdowns are carried out on a magnetically insulated transmission-line oscillators, which is capable of generating HPM with pulse duration of 30 ns, and frequency of 1.74 GHz. The typical breakdown waveforms of air and SF{sub 6} are presented. Besides, the breakdown field strengths of the two gases are derived at different pressures. It is found that the effects of air and SF{sub 6} breakdown on the transmission of HPM are different: air breakdown mainly shortens the pulse width of HPM while SF{sub 6} breakdown mainly reduces the peak output power of HPM. The electric field threshold of SF{sub 6} is about 2.4 times larger than that of air. These differences suggest that gas properties have a great effect on the transmission characteristic of HPM in gases.

  5. A high-power 626 nm diode laser system for Beryllium ion trapping

    E-Print Network [OSTI]

    H. Ball; M. W. Lee; S. D. Gensemer; M. J. Biercuk

    2013-04-07T23:59:59.000Z

    We describe a high-power, frequency-tunable, external cavity diode laser (ECDL) system near 626 nm useful for laser cooling of trapped $^9$Be$^+$ ions. A commercial single-mode laser diode with rated power output of 170 mW at 635 nm is cooled to $\\approx - 31$ C, and a single longitudinal mode is selected via the Littrow configuration. In our setup, involving multiple stages of thermoelectric cooling, we are able to obtain $\\approx$130 mW near 626 nm, sufficient for efficient frequency doubling to the required Doppler cooling wavelengths near 313 nm in ionized Beryllium. In order to improve nonlinear frequency conversion efficiency, we achieve larger useful power via injection locking of a slave laser. In this way the entirety of the slave output power is available for frequency doubling, while analysis may be performed on the master output. We believe that this simple laser system addresses a key need in the ion trapping community and dramatically reduces the cost and complexity associated with Beryllium ion trapping experiments.

  6. Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges

    SciTech Connect (OSTI)

    Stranak, Vitezslav, E-mail: stranak@prf.jcu.cz [Faculty of Science, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice (Czech Republic); Hubicka, Zdenek; Cada, Martin [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Drache, Steffen; Hippler, Rainer [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Tichy, Milan [Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, 180 00 Prague (Czech Republic)

    2014-04-21T23:59:59.000Z

    The metal ionized flux fraction and production of double charged metal ions Me{sup 2+} of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ?. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me{sup 2+} and singly Me{sup +} charged metal ions was determined. It is shown that ECWR assistance enhances Me{sup 2+} production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me{sup 2+} was observed.

  7. Boron-rich plasma by high power impulse magnetron sputtering of lanthanum hexaboride

    SciTech Connect (OSTI)

    Oks, Efim M. [State University of Control Systems and Radioelectronics, Tomsk (Russian Federation); Anders, Andre [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2012-10-15T23:59:59.000Z

    Boron-rich plasmas have been obtained using a LaB{sub 6} target in a high power impulse sputtering (HiPIMS) system. The presence of {sup 10}B{sup +}, {sup 11}B{sup +}, Ar{sup 2+}, Ar{sup +}, La{sup 2+}, and La{sup +} and traces of La{sup 3+}, {sup 12}C{sup +}, {sup 14}N{sup +}, and {sup 16}O{sup +} have been detected using an integrated mass and energy spectrometer. Peak currents as low as 20 A were sufficient to obtain plasma dominated by {sup 11}B{sup +} from a 5 cm planar magnetron. The ion energy distribution function for boron exhibits an energetic tail extending over several 10 eV, while argon shows a pronounced peak at low energy (some eV). This is in agreement with models that consider sputtering (B, La) and gas supply (from background and 'recycling'). Strong voltage oscillations develop at high current, greatly affecting power dissipation and plasma properties.

  8. Neutronic and thermal calculation of blanket for high power operating condition of fusion reactor

    SciTech Connect (OSTI)

    Sagawa, H.; Shimakawa, S.; Kuroda, T. [Oarai Research Establishement of JAERI, Ibaraki (Japan)] [and others

    1994-12-31T23:59:59.000Z

    Internal (breeding region) structures of ceramic breeder blanket to accommodate high power operating conditions such as a DEMO reactor have been investigated. The conditions considered here are the maximum neutron wall load of 2.8 MW/m{sup 2} at outboard midplane corresponding to a fusion power of 3.0 GW and the coolant temperature of 200{degrees}C. Structure of a blanket is based on the layered pebble bed concept, which has been proposed by Japan since the ITER CDA. Lithium oxide with 50% enriched {sup 6}Li is used in a shape of small spherical pebbles which are filled in a 316SS can avoid its compatibility issue with Be. Beryllium around the breeder can is filled also in a shape of spherical pebbles which works not only as a neutron multiplier but also as a thermal resistant layer to maintain breeder temperature for effective in-situ tritium recovery. Diameters and packing fractions of both pebbles are {<=} 1 mm and 65%, respectively. A layer of block Be between cooling panels is introduced as a neutron multiplier (not as the thermal resistant layer) to enhance tritium breeding performance. Inlet temperature of water coolant is 200{degrees}C to meet the high temperature conditioning requirement to the first wall which is one of walls of the blanket vessel. Neutronics calculations have been carried out by one-dimensional transport code, and thermal calculations have also been carried out by one-dimensional slab code.

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

    SciTech Connect (OSTI)

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

    2012-07-01T23:59:59.000Z

    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.

  10. Time-resolved temperature study in a high-power impulse magnetron sputtering discharge

    SciTech Connect (OSTI)

    Britun, Nikolay; Palmucci, Maria; Konstantinidis, Stephanos [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Gaillard, Mireille [Groupe de Recherches sur l'Energetique des Milieux Ionises (GREMI), UMR 7344, Universite d'Orleans, 14 rue d'Issoudun, B.P. 6744, 45067 Orleans Cedex 2 (France); Snyders, Rony [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Center, Parc Initialis, B-7000 Mons (Belgium)

    2013-07-07T23:59:59.000Z

    The gas heating dynamics is studied in a high-power impulse magnetron sputtering discharge operating in Ar-N{sub 2} gas mixtures. The time-resolved rotational temperature analysis based on the spectral transition between the B{sup 2}{Sigma}{sub u}{sup +}-X{sup 2}{Sigma}{sub g}{sup +} energy levels in molecular nitrogen ion (N{sub 2}{sup +} First Negative Band) is undertaken for this purpose. The rotational temperature in the discharge is found to increase linearly during the plasma pulse being roughly independent on the nitrogen content in the examined range. Such a temperature increase is attributed to the bulk gas heating which is the result of collisions with the sputtered species. Two sputtered materials, Ti and W, are examined during the study. In the case of W sputtering, the gas heating is found to be more pronounced than in the Ti case, which is explained by more efficient energy exchange between the sputtered W atoms and the bulk gas atoms during the plasma on-time. The obtained temperature data are compared to the laser-induced fluorescence study of Ar metastable atoms performed recently in the same discharge in our group. The particularities related to gas thermalization as well as to validity of the utilized approach for characterization of the pulsed sputtering discharges are discussed.

  11. Successful High Power Acceleration of the HSC Type Injector for Cancer Therapy in IMP

    E-Print Network [OSTI]

    Liang Lu

    2015-03-25T23:59:59.000Z

    A Hybrid single cavity (HSC) linac, which is formed by combining a radio frequency quadrupole (RFQ) structure and a drift tube (DT) structure into one interdigital-H (IH) cavity, is fabricated and assembled as a proof of principle (PoP) type injector for cancer therapy synchrotron according to the series researches. The injection method of the HSC linac adopt a direct plasma injection scheme (DPIS), which is considered to be the only method for accelerating an intense current heavy ion beam produced by a laser ion source (LIS). The input beam current of the HSC was designed to be 20 milliampere (mA) C6+ ions. According to numerical simulations, the HSC linac could accelerate a 6-mA C6+ beam which meets requirement of the needed particle number for cancer therapy use (108~9 ions per pulse). The injection system adopted HSC injector with the method of DPIS can make the existing multi-turn injection system and the stripping system unnecessary, and also can make the beam pipe of the existing synchrotron magnets downsize which could reduce the whole cost of synchrotron (estimated millions dollars). Details of the measurements and evaluations of the assembled HSC linac, and the results of the high power test using a LIS with DPIS are reported in this paper.

  12. ZrN coatings deposited by high power impulse magnetron sputtering and cathodic arc techniques

    SciTech Connect (OSTI)

    Purandare, Yashodhan, E-mail: Y.Purandare@shu.ac.uk; Ehiasarian, Arutiun; Hovsepian, Papken [Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Santana, Antonio [Ionbond AG Olten, Industriestrasse 211, CH-4600 Olten (Switzerland)

    2014-05-15T23:59:59.000Z

    Zirconium nitride (ZrN) coatings were deposited on 1??m finish high speed steel and 316L stainless steel test coupons. Cathodic Arc (CA) and High Power Impulse Magnetron Sputtering (HIPIMS) + Unbalanced Magnetron Sputtering (UBM) techniques were utilized to deposit coatings. CA plasmas are known to be rich in metal and gas ions of the depositing species as well as macroparticles (droplets) emitted from the arc sports. Combining HIPIMS technique with UBM in the same deposition process facilitated increased ion bombardment on the depositing species during coating growth maintaining high deposition rate. Prior to coating deposition, substrates were pretreated with Zr{sup +} rich plasma, for both arc deposited and HIPIMS deposited coatings, which led to a very high scratch adhesion value (L{sub C2}) of 100 N. Characterization results revealed the overall thickness of the coatings in the range of 2.5??m with hardness in the range of 30–40?GPa depending on the deposition technique. Cross-sectional transmission electron microscopy and tribological experiments such as dry sliding wear tests and corrosion studies have been utilized to study the effects of ion bombardment on the structure and properties of these coatings. In all the cases, HIPIMS assisted UBM deposited coating fared equal or better than the arc deposited coatings, the reasons being discussed in this paper. Thus H+U coatings provide a good alternative to arc deposited where smooth, dense coatings are required and macrodroplets cannot be tolerated.

  13. A source of high-power pulses of elliptically polarized ultrawideband radiation

    SciTech Connect (OSTI)

    Andreev, Yu. A., E-mail: andreev@lhfe.hcei.tsc.ru; Efremov, A. M.; Koshelev, V. I.; Kovalchuk, B. M.; Petkun, A. A.; Sukhushin, K. N.; Zorkaltseva, M. Yu. [Institute of High Current Electronics SB RAS, IHCE SB RAS, Tomsk 634055 (Russian Federation)

    2014-10-01T23:59:59.000Z

    Here, we describe a source of high-power ultrawideband radiation with elliptical polarization. The source consisting of a monopolar pulse generator, a bipolar pulse former, and a helical antenna placed into a radioparent container may be used in tests for electromagnetic compatibility. In the source, the helical antenna with the number of turns N = 4 is excited with a high-voltage bipolar pulse. Preliminary, we examined helical antennas at a low-voltage source aiming to select an optimal N and to estimate a radiation center position and boundary of a far-field zone. Finally, characteristics of the source in the operating mode at a pulse repetition rate of 100 Hz are presented in the paper as well. Energy efficiency of the antenna is 0.75 at the axial ratio equal to 1.3. The effective potential of radiation of the source at the voltage amplitudes of the bipolar pulse generator equal to -175/+200 kV reaches 280 kV.

  14. Air Electrode Design for Sustained High Power Operation of Li/air Batteries

    SciTech Connect (OSTI)

    Williford, Ralph E.; Zhang, Jiguang

    2009-08-31T23:59:59.000Z

    The rapid development of portable electronic devices increasingly requires much more energy to support advanced functions. However, currently available batteries do not meet the high energy requirement of these devices. Metal/air batteries, especially Li/air batteries, have a much higher specific energy than most other available batteries, but their power rate is limited by the accumulation of reaction products in the air electrode. Several approaches to improve the power rate of Li/air batteries have been analyzed in this work, including adjustment of air electrode porosity and catalyst reactivity distributions to minimize diffusion limitations and maximize air electrode material utilization. An interconnected dual pore system (one catalyzed and one noncatalyzed) is proposed to improve oxygen transport into the inner regions of the air electrode, but this approach alone cannot supply high power for long term applications. A time-release multiple catalyst approach is analyzed to provide temporal release of reactivity in the air electrode. When coupled with the dual pore configuration and catalysts with high reactivities, the time-release catalyst concept can extend the duration of higher powers to longer times, and result in maximum utilization of air electrode materials.

  15. Downstream plasma transport and metal ionization in a high-powered pulsed-plasma magnetron

    SciTech Connect (OSTI)

    Meng, Liang; Szott, Matthew M.; McLain, Jake T.; Ruzic, David N. [Center for Plasma-Materials Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Yu, He [Center for Plasma-Materials Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2014-06-14T23:59:59.000Z

    Downstream plasma transport and ionization processes in a high-powered pulsed-plasma magnetron were studied. The temporal evolution and spatial distribution of electron density (n{sub e}) and temperature (T{sub e}) were characterized with a 3D scanning triple Langmuir probe. Plasma expanded from the racetrack region into the downstream region, where a high n{sub e} peak was formed some time into the pulse-off period. The expansion speed and directionality towards the substrate increased with a stronger magnetic field (B), largely as a consequence of a larger potential drop in the bulk plasma region during a relatively slower sheath formation. The fraction of Cu ions in the deposition flux was measured on the substrate using a gridded energy analyzer. It increased with higher pulse voltage. With increased B field from 200 to 800 Gauss above racetrack, n{sub e} increased but the Cu ion fraction decreased from 42% to 16%. A comprehensive model was built, including the diffusion of as-sputtered Cu flux, the Cu ionization in the entire plasma region using the mapped n{sub e} and T{sub e} data, and ion extraction efficiency based on the measured plasma potential (V{sub p}) distribution. The calculations matched the measurements and indicated the main causes of lower Cu ion fractions in stronger B fields to be the lower T{sub e} and inefficient ion extraction in a larger pre-sheath potential.

  16. Polaron Coherence Condensation in Layered Colossal Resistive...

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

    are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides. Coherence Rules the Day When physicists speak of coherence, they are...

  17. Laser beat wave excitation of terahertz radiation in a plasma slab

    SciTech Connect (OSTI)

    Chauhan, Santosh; Parashar, Jetendra, E-mail: j.p.parashar@gmail.com [Department of Applied Physics, Samrat Ashok Technological Institute, Vidisha 464001, Madhya Pradesh (India)

    2014-10-15T23:59:59.000Z

    Terahertz (THz) radiation generation by nonlinear mixing of lasers, obliquely incident on a plasma slab is investigated. Two cases are considered: (i) electron density profile is parabolic but density peak is below the critical density corresponding to the beat frequency, (ii) plasma boundaries are sharp and density is uniform. In both cases, nonlinearity arises through the ponderomotive force that gives rise to electron drift at the beat frequency. In the case of inhomogeneous plasma, non zero curl of the nonlinear current density gives rise to electromagnetic THz generation. In case of uniform plasma, the sharp density variation at the plasma boundaries leads to radiation generation. In a slab width of less than a terahertz wavelength, plasma density one fourth of terahertz critical density, laser intensities ?10{sup 17?}W/cm{sup 2} at 1??m, one obtains the THz intensity ?1?GW/cm{sup 2} at 3 THz radiation frequency.

  18. Status report on Jefferson Lab`s high-power infrared free-electron laser

    SciTech Connect (OSTI)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-10-01T23:59:59.000Z

    Jefferson Lab is building a free-electron laser to produce tunable, continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting accelerator will drive the laser, and a transport lattice will recirculate the beam back through the accelerator for energy recovery. Space charge in the injector and coherent synchrotron radiation in magnetic bends will be present, and the machine is instrumented to study these phenomena during commissioning. The wiggler and optical cavity are conventional; however, significant analysis and testing was needed to ensure mirror heating at 1 kW of outcoupled power would not impede performance. The FEL is being installed in its own facility, and installation will be finished in Fall 1997. This paper surveys the machine, the status of its construction, and plans for its commissioning.

  19. Beam manipulation techniques, nonlinear beam dynamics, and space charge effect in high energy high power accelerators

    SciTech Connect (OSTI)

    Lee, S. Y.

    2014-04-07T23:59:59.000Z

    We had carried out a design of an ultimate storage ring with beam emittance less than 10 picometer for the feasibility of coherent light source at X-ray wavelength. The accelerator has an inherent small dynamic aperture. We study method to improve the dynamic aperture and collective instability for an ultimate storage ring. Beam measurement and accelerator modeling are an integral part of accelerator physics. We develop the independent component analysis (ICA) and the orbit response matrix method for improving accelerator reliability and performance. In collaboration with scientists in National Laboratories, we also carry out experimental and theoretical studies on beam dynamics. Our proposed research topics are relevant to nuclear and particle physics using high brightness particle and photon beams.

  20. A thermally self-sustained micro solid-oxide fuel-cell stack with high power density

    E-Print Network [OSTI]

    Haile, Sossina M.

    A thermally self-sustained micro solid-oxide fuel-cell stack with high power density Zongping Shao1 design challenges and cannot operate with hydrocarbon fuels of higher energy density. Solid-oxide fuel cells (SOFCs) enable direct use of higher hydrocarbons4­6 , but have not been seriously con- sidered

  1. IEEE ELECTRON DEVICE LETTERS, VOL. 28, NO. 5, MAY 2007 357 Direct Monitoring of RF Overstress in High-Power

    E-Print Network [OSTI]

    Shapira, Yoram

    Shapira, Senior Member, IEEE Abstract--Light emission from power transistors at a com- pression level Terms--Breakdown, high-power amplifier (HPA), impact ionization, light emission, parasitic oscillations improved in terms of power density, efficiency, and gain without any reduction in reliability re

  2. IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 55, NO. 4, APRIL 2008 1067 Nonuniform RF Overstress in High-Power

    E-Print Network [OSTI]

    Shapira, Yoram

    , IEEE Abstract--Nonuniform light emission from power transistors at 2­3-dB compression levels has been), light emission, parasitic oscillations, power transistor. I. INTRODUCTION THE PERFORMANCE of high-power amplifiers (HPAs) is continually being improved in terms of power density, efficiency, and gain, without any

  3. Performance Optimization of Battery-Super Capacitor Hybrid System Electrochemical capacitors (ultracapacitors) offer high power density when compared to battery

    E-Print Network [OSTI]

    Popov, Branko N.

    Performance Optimization of Battery-Super Capacitor Hybrid System Electrochemical capacitors a decreased value of power and energy densities for the hybrid system. Figure 1shows the fractional capacity (ultracapacitors) offer high power density when compared to battery systems and also have a relatively large energy

  4. HIGH-POWER PRECISION CURRENT SUPPLY IST2-1000M FOR ELEMENTS OF MAGNETIC SYSTEMS OF ACCELERATORS AND

    E-Print Network [OSTI]

    Kozak, Victor R.

    HIGH-POWER PRECISION CURRENT SUPPLY IST2-1000M FOR ELEMENTS OF MAGNETIC SYSTEMS OF ACCELERATORS. These supplies are intended to power magnetic systems of accelerators, requiring high stability and low ripples current at non-inductive load % 0,02 Rate of current raise without disturbing operation of the system

  5. Technology Survey and Performance Scaling for the Design of High Power Nuclear Electric Power and Propulsion Systems

    E-Print Network [OSTI]

    , use of electric primary propulsion in flight systems has been limited to low-power, solar electric thruster output power are identified. Design evolutions are presented for three thrusters that would1 Technology Survey and Performance Scaling for the Design of High Power Nuclear Electric Power

  6. Fully-automatic laser welding and micro-sculpting with universal in situ inline coherent imaging

    E-Print Network [OSTI]

    Webster, Paul J L; Ji, Yang; Galbraith, Christopher M; Kinross, Alison W; Van Vlack, Cole; Fraser, James M

    2014-01-01T23:59:59.000Z

    Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a process as violent as kW-class keyhole welding. We exploit ICI's high speed, high dynamic range and robustness to interference from other optical sources to achieve fully automatic, adaptive control of laser welding as well as ablation, achieving micron-scale sculpting in vastly different heterogeneous biological materials.

  7. Physics Design of the National High-power Advanced Torus Experiment

    SciTech Connect (OSTI)

    Menard, J E; Fu, G -Y; Gorelenkov, N; Kaye, S M; Kramer, G; Maingi, R; Neumeyer, C L; Sabbagh, S A; Soukhanovskii, V A

    2007-07-18T23:59:59.000Z

    Moving beyond ITER toward a demonstration power reactor (Demo) will require the integration of stable high fusion gain in steady-state, advanced methods for dissipating very high divertor heat-fluxes, and adherence to strict limits on in-vessel tritium retention. While ITER will clearly address the issue of high fusion gain, and new and planned long-pulse experiments (EAST, JT60-SA, KSTAR, SST-1) will collectively address stable steady-state highperformance operation, none of these devices will adequately address the integrated heat-flux, tritium retention, and plasma performance requirements needed for extrapolation to Demo. Expressing power exhaust requirements in terms of Pheat/R, future ARIES reactors are projected to operate with 60-200MW/m, a Component Test Facility (CTF) or Fusion Development Facility (FDF) for nuclear component testing (NCT) with 40-50MW/m, and ITER 20-25MW/m. However, new and planned long-pulse experiments are currently projected to operate at values of Pheat/R no more than 16MW/m. Furthermore, none of the existing or planned experiments are capable of operating with very high temperature first-wall (Twall = 600-1000C) which may be critical for understanding and ultimately minimizing tritium retention with a reactor-relevant metallic first-wall. The considerable gap between present and near-term experiments and the performance needed for NCT and Demo motivates the development of the concept for a new experiment — the National High-power advanced-Torus eXperiment (NHTX) — whose mission is to study the integration of a fusion-relevant plasma-material interface with stable steady-state high-performance plasma operation.

  8. High-power liquid-lithium jet target for neutron production

    SciTech Connect (OSTI)

    Halfon, S.; Feinberg, G. [Soreq NRC, Yavne 81800 (Israel) [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Arenshtam, A.; Kijel, D.; Berkovits, D.; Eliyahu, I.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Silverman, I. [Soreq NRC, Yavne 81800 (Israel)] [Soreq NRC, Yavne 81800 (Israel); Paul, M.; Friedman, M.; Tessler, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)] [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2013-12-15T23:59:59.000Z

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the {sup 7}Li(p,n){sup 7}Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm{sup 3}) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the {sup 7}Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ?200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm{sup 2} and volume power density of ?2 MW/cm{sup 3} at a lithium flow of ?4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91–2.5 MeV, 1–2 mA) at SARAF.

  9. A high power beam-on-target test of liquid lithium target for RIA.

    SciTech Connect (OSTI)

    Nolen, J.; Reed, C.; Novick, V.; Specht, J.; Plotkin, P.; Momozaki,Y.; Gomes, I.

    2005-08-29T23:59:59.000Z

    Experiments were conducted to demonstrate the stable operation of a windowless liquid lithium target under extreme thermal loads that are equivalent to uranium beams from the proposed Rare Isotope Accelerator (RIA) driver linac. The engineering and safety issues accompanying liquid lithium systems are first discussed. The liquid metal technology knowledge base generated primarily for fast reactors, and liquid metal cooled fusion reactors, was applied to the development of these systems in a nuclear physics laboratory setting. The use of a high energy electron beam for simulating a high power uranium beam produced by the RIA driver linac is also described. Calculations were performed to obtain energy deposition profiles produced by electron beams at up to a few MeV to compare with expected uranium beam energy deposition profiles. It was concluded that an experimental simulation using a 1-MeV electron beam would be a valuable tool to assess beam-jet interaction. In the experiments, the cross section of the windowless liquid lithium target was 5 mm x 10 mm, which is a 1/3rd scale prototype target, and the velocity of the liquid lithium was varied up to 6 m/s. Thermal loads up to 20 kW within a beam spot diameter of 1mm were applied on the windowless liquid lithium target by the 1-MeV electron beam. The calculations showed that the maximum power density and total power deposited within the target, from the electron beam, was equivalent to that of a 200-kW, 400-MeV/u uranium beam. It was demonstrated that the windowless liquid lithium target flowing at velocities as low as 1.8 m/s stably operated under beam powers up to 20 kW without disruption or excessive vaporization.

  10. Use of the LEDA Facility as an ADS High-Power Accelerator Test Bed

    SciTech Connect (OSTI)

    Garnett, R. W. (Robert W.); Sheffield, R. L. (Richard L.)

    2003-01-01T23:59:59.000Z

    The Low-Energy Demonstration Accelerator (LEDA) was built to generate high-current proton beams. Its successful full-power operation and testing in 1999-2001 confirmed the feasibility of a high-power linear accelerator (linac) front end, the most technically challenging portion of such a machine. The 6.7-MeV accelerator operates reliably at 95-mA CW beam current with few interruptions orjaults, and qualiJes as one of the most powerful accelerators in the world. LEDA is now available to address the needs of other programs. LEDA can be upgraded in a staged fashion to allow for full-power accelerator demonstrations. The proposed post-h!FQ accelerator structures are 350-MHz superconducting spoke cavities developed for the AAA /APT program. The superconducting portion of the accelerator is designed for a IOO-mA proton beam current. Superconducting cavities were chosen because of the signijkant thermal issues with room-temperature structures, the larger superconducting cavity apertures, and the lower operating costs ('because of improved electrical efficiency) of a superconducting accelerator. Since high reliability is a major issue for an ADS system, the superconducting design architecture alIows operation through faults due to the failure of single magnets or superconducting cavities. The presently installed power capacity of 13 MVA of input ACpower is capable of supporting a 40-MeVproton beam at 100 mA. (The input power is easily expandable to 25 MVA, allowing up to 100-MeV operation). Operation at 40-MeV would provide a complete demonstration of all of the critical accelerator sub-systems ofa full-power ADS system.

  11. Study of second harmonic generation by high power laser beam in magneto plasma

    SciTech Connect (OSTI)

    Sharma, Prerana [Ujjain Engineering College, Ujjain, Madhya Pradesh 465010 (India); Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

    2012-12-15T23:59:59.000Z

    This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency {omega}{sub c}=eB{sub 0}/mc over the laser frequency {omega}{sub 0} has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B{sub 0} is the externally applied magnetic field.

  12. High-power laser and arc welding of thorium-doped iridium alloys

    SciTech Connect (OSTI)

    David, S.A.; Liu, C.T.

    1980-05-01T23:59:59.000Z

    The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

  13. Durability of Low Platinum Fuel Cells Operating at High Power Density

    SciTech Connect (OSTI)

    Polevaya, Olga [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab] [Argonne National Lab; Borup, Rod [Los-Alamos National Lab] [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab] [Los-Alamos National Lab

    2014-03-19T23:59:59.000Z

    Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (?0.2mg/cm2) operating at high power density (?1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss was correlated with the upper potential limit in the cycle tests, although the performance degradation was found to be a strong function of initial Pt loading. A large fraction of the voltage degradation was found due to increased mass transfer overpotentials, especially in the lower Pt loading cells. Increased mass transfer overpotentials were responsible for a large fraction of the voltage degradation at high current densities. Analysis of the impedance and polarization data indicated O2 diffusion in the aged electrode ionomer to be the main source of the increased mass transfer overpotentials. Results from the experimental parametric studies were used to inform and calibrate newly developed durability model, simulating lifetime performance of the fuel cell under variety of load-cycle protocols, electrode loadings and throughout wide range of operating conditions, including elevated-to-3.0A/cm2 current densities. Complete durability model included several sub-models: platinum dissolution-and-growth as well as reaction-diffusion model of cathode electrode, applied sequentially to study the lifetime predictions of ECSA and polarization performance in the ASTs and NSTs. These models establish relations between changes in overpotentials, ECSA and oxygen mass transport in fuel cell cathodes. The model was calibrated using single cells with land-channel and open flowfield architectures. The model was validated against Nuvera Orion® (open flowfield) short stack data in the load cycle durability tests. The reaction-diffusion model was used to correlate the effective mass transfer coefficients for O2 diffusion in cathode ionomer and separately in gas pores with the operating conditions (pressure, temperature, gas velocity in flow field and current density), Pt loading, and ageing related growth in Pt particles and thinning of the electrode. Achievements of both modeling and experimental objectives were demonstrated in a full format, subscale stacks operating in a simulated but fully realistic ambient environment, using system-compatible operating protocols.

  14. Proposal to negotiate the renewal of a blanket purchase contract for the supply of high-power RF grid-tubes for the CERN accelerators

    E-Print Network [OSTI]

    2014-01-01T23:59:59.000Z

    Proposal to negotiate the renewal of a blanket purchase contract for the supply of high-power RF grid-tubes for the CERN accelerators

  15. Graphene-based terahertz tunable plasmonic directional coupler

    SciTech Connect (OSTI)

    He, Meng-Dong, E-mail: hemendong@sohu.com; Wang, Kai-Jun; Wang, Lei; Li, Jian-Bo [Institute of Mathematics and Physics, Central South University of Forestry and Technology, Changsha 410004 (China); Liu, Jian-Qiang [College of Science, Jiujiang University, Jiujiang 332005 (China); Huang, Zhen-Rong; Wang, Lingling [Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, Hunan University, Changsha 410082 (China); Wang, Lin; Hu, Wei-Da; Chen, Xiaoshuang [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China)

    2014-08-25T23:59:59.000Z

    We propose and numerically analyze a terahertz tunable plasmonic directional coupler which is composed of a thin metal film with a nanoscale slit, dielectric grating, a graphene sheet, and a dielectric substrate. The slit is employed to generate surface plasmon polaritons (SPPs), and the metal-dielectric grating-graphene-dielectric constructs a Bragg reflector, whose bandgap can be tuned over a wide frequency range by a small change in the Fermi energy level of graphene. As a graphene-based Bragg reflector is formed on one side of the slit, the structure enables SPP waves to be unidirectionally excited on the other side of the slit due to SPP interference, and the SPP waves in the Bragg reflector can be efficiently switched on and off by tuning the graphene's Fermi energy level. By introducing two optimized graphene-based Bragg reflectors into opposite sides of the slit, SPP waves can be guided to different Bragg reflectors at different Fermi energy levels, thus achieving a tunable bidirectional coupler.

  16. Coherent control of plasma dynamics

    E-Print Network [OSTI]

    He, Z -H; Lebailly, V; Nees, J A; Krushelnick, K; Thomas, A G R

    2015-01-01T23:59:59.000Z

    Coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field. Plasmas support coherent wave structures that can be generated by intense laser fields. Here, we demonstrate the coherent control of plasma dynamics in a laser wakefield electron acceleration experiment. A genetic algorithm is implemented using a deformable mirror with the electron beam signal as feedback, which allows a heuristic search for the optimal wavefront under laser-plasma conditions that is not known a priori. We are able to improve both the electron beam charge and angular distribution by an order of magnitude. These improvements do not simply correlate with having the `best' focal spot, since the highest quality vacuum focal spot produces a greatly inferior electron beam, but instead correspond to the particular laser phase that steers the plasma wave to a final state with optimal accelerating fields.

  17. Coherent control of neutron interferometry

    E-Print Network [OSTI]

    Pushin, Dmitry A

    2007-01-01T23:59:59.000Z

    In this thesis, several novel techniques are proposed and demonstrated for measuring the coherent properties of materials and testing aspects of quantum information processing using a single crystal neutron interferometer. ...

  18. Highly Efficient Coherent Raman Generation

    E-Print Network [OSTI]

    Hua, Xia

    2014-08-04T23:59:59.000Z

    , and to my daughter Christina Tzu-Hsin Hua for the happiness she brings to me. vii NOMENCLATURE SpRS spontaneous Raman scattering SRS stimulated Raman scattering CARS coherent anti-Stokes Raman scattering CSRS coherent Stokes Raman scattering... wavelength at 672 nm. ................................................................................... 75 Figure 41 The electric field spectral amplitudes of the incident pump (green), Stokes (orange), and probe (red) laser pulses with normalized...

  19. Quantum coherence and correlations in quantum system

    E-Print Network [OSTI]

    Zhengjun Xi; Yongming Li; Heng Fan

    2014-12-24T23:59:59.000Z

    Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we firstly give an uncertainty-like expression relating the coherence and the entropy of quantum system. Then, we obtain three trade-offs among the coherence, the discord and the deficit in the bipartite quantum system.As a consequence, we obtain that the relative entropy of coherence satisfies the super-additivity. Finally, we discuss the relations between the entanglement and the coherence.

  20. Composite Cathode for High-Power Density Solid Oxide Fuel Cells

    SciTech Connect (OSTI)

    Ilwon Kim; Scott Barnett; Yi Jiang; Manoj Pillai; Nikkia McDonald; Dan Gostovic; Zhongryang Zhan; Jiang Liu

    2004-01-31T23:59:59.000Z

    Reduction of solid oxide fuel cell (SOFC) operating temperature will play a key role in reducing the stack cost by allowing the use of low-cost metallic interconnects and new approaches to sealing, while making applications such as transportation more feasible. Reported results for anode-supported SOFCs show that cathode polarization resistance is the primary barrier to achieving high power densities at operating temperatures of 700 C and lower. This project aims to identify and develop composite cathodes that could reduce SOFC operating temperatures below 700 C. This effort focuses on study and use of (La,Sr)(Co,Fe)O{sub 3} (LSCF) based composite cathodes, which have arguably the best potential to substantially improve on the currently-used, (La,Sr)MnO{sub 3}-Yttria-stabilized Zirconia. During this Phase I, it was successfully demonstrated that high performances can be achieved with LSCF/Gadolinium-Doped Ceria composite cathodes on Ni-based anode supported cells operating at 700 C or lower. We studied electrochemical reactions at LSCF/Yttria-stabilized Zirconia (YSZ) interfaces, and observed chemical reactions between LSCF and YSZ. By using ceria electrolytes or YSZ electrolytes with ceria diffusion barrier layers, the chemical reactions between LSCF and electrolytes were prevented under cathode firing conditions necessary for the optimal adhesion of the cathodes. The protection provided by ceria layer is expected to be adequate for stable long-term cathode performances, but more testing is needed to verify this. Using ceria-based barrier layers, high performance Ni-YSZ anode supported cells have been demonstrated with maximum power densities of 0.8W/cm2 at 700 C and 1.6W/cm{sup 2} at 800 C. Ni-SDC anode supported cells with SDC electrolytes yielded >1W/cm{sup 2} at 600 C. We speculate that the power output of Ni-YSZ anode supported cell at 700 C and lower, was limited by the quality of the Ceria and Ceria YSZ interface. Improvements in the low-temperature performances are expected based on further development of barrier layer fabrication processes and optimization of cathode microstructure.

  1. A NEW CROWBAR SYSTEM FOR THE PROTECTION OF HIGH POWER GRIDDED TUBES AND MICROWAVE DEVICES

    SciTech Connect (OSTI)

    S.G.E. PRONKO; T.E.HARRIS

    2001-04-01T23:59:59.000Z

    As part of the electron cyclotron heating (ECH) facility upgrade at the DIII-D National Fusion Facility, two 8.4 MW modulator/regulator power systems were designed and constructed (Ref. 1). Each power system uses a high power tetrode to modulate and regulate the cathode voltage for two 1 MW-class 110 GHz gyrotrons (Ref. 2). A critical element in the power system is the fault energy divertor, or crowbar switch, that protects the tetrode and the gyrotrons in the event of an arc fault. Traditionally, mercury filled ignitron switches are used for this application, but it was desired to eliminate hazardous materials and improve overall switching performance. The new crowbar switch system was required to meet the following requirements: Operating voltage: -105 kVdc; Peak current (750 ms e-fold): 1.6 kA; Follow-on current: <1 kA (25 ms); Charge transfer per shot: <15 Cb; and Turn-on time: <1 {micro}s. The switch that was chosen for the new design is a low pressure deuterium filled device, called a metal-arc thyratron, manufactured by Marconi Applied Technologies (Ref. 3). In addition to the new crowbar switch assembly, improved fault signal processing circuitry was developed. This new circuitry uses fiber-optics for signal and trigger transmission and a complex programmable logic device for high speed signal and logic processing. Two generations of metal-arc thyratrons have been commissioned in the two ECH power systems constructed at DIII-D. In the first, the crowbar system performed extremely well, meeting all of the operating requirements and demonstrating its ability to protect a 36 gauge copper wire from fusing (energy let-through <10 J). However, after accumulating over 500 shots, the metal-arc thyratrons lost their ability to reliably hold-off voltage. This problem was solved by Marconi with a design modification of the thyratron electrodes. The second generation tubes were installed in the second ECH power system. The crowbar system was fully commissioned and all of the performance requirements were satisfactorily achieved. The design of the crowbar switch and the fault signal processing system and their performance will be presented in this paper.

  2. HIGH-POWER TURBODRILL AND DRILL BIT FOR DRILLING WITH COILED TUBING

    SciTech Connect (OSTI)

    Robert Radtke; David Glowka; Man Mohan Rai; David Conroy; Tim Beaton; Rocky Seale; Joseph Hanna; Smith Neyrfor; Homer Robertson

    2008-03-31T23:59:59.000Z

    Commercial introduction of Microhole Technology to the gas and oil drilling industry requires an effective downhole drive mechanism which operates efficiently at relatively high RPM and low bit weight for delivering efficient power to the special high RPM drill bit for ensuring both high penetration rate and long bit life. This project entails developing and testing a more efficient 2-7/8 in. diameter Turbodrill and a novel 4-1/8 in. diameter drill bit for drilling with coiled tubing. The high-power Turbodrill were developed to deliver efficient power, and the more durable drill bit employed high-temperature cutters that can more effectively drill hard and abrasive rock. This project teams Schlumberger Smith Neyrfor and Smith Bits, and NASA AMES Research Center with Technology International, Inc (TII), to deliver a downhole, hydraulically-driven power unit, matched with a custom drill bit designed to drill 4-1/8 in. boreholes with a purpose-built coiled tubing rig. The U.S. Department of Energy National Energy Technology Laboratory has funded Technology International Inc. Houston, Texas to develop a higher power Turbodrill and drill bit for use in drilling with a coiled tubing unit. This project entails developing and testing an effective downhole drive mechanism and a novel drill bit for drilling 'microholes' with coiled tubing. The new higher power Turbodrill is shorter, delivers power more efficiently, operates at relatively high revolutions per minute, and requires low weight on bit. The more durable thermally stable diamond drill bit employs high-temperature TSP (thermally stable) diamond cutters that can more effectively drill hard and abrasive rock. Expectations are that widespread adoption of microhole technology could spawn a wave of 'infill development' drilling of wells spaced between existing wells, which could tap potentially billions of barrels of bypassed oil at shallow depths in mature producing areas. At the same time, microhole coiled tube drilling offers the opportunity to dramatically cut producers' exploration risk to a level comparable to that of drilling development wells. Together, such efforts hold great promise for economically recovering a sizeable portion of the estimated remaining shallow (less than 5,000 feet subsurface) oil resource in the United States. The DOE estimates this U.S. targeted shallow resource at 218 billion barrels. Furthermore, the smaller 'footprint' of the lightweight rigs utilized for microhole drilling and the accompanying reduced drilling waste disposal volumes offer the bonus of added environmental benefits. DOE analysis shows that microhole technology has the potential to cut exploratory drilling costs by at least a third and to slash development drilling costs in half.

  3. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    SciTech Connect (OSTI)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-06-01T23:59:59.000Z

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

  4. IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 7, NO. 1, JANUARY 2008 91 Graphene Terahertz Plasmon Oscillators

    E-Print Network [OSTI]

    Afshari, Ehsan

    IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 7, NO. 1, JANUARY 2008 91 Graphene Terahertz Plasmon on charge density wave (plasmon) amplifi- cation in two-dimensional graphene. The coupling of the plasmons to interband electron­hole transitions in population inverted graphene layers can lead to plasmon amplification

  5. Plasmonic and bolometric terahertz detection by graphene field-effect A. V. Muraviev,1,a)

    E-Print Network [OSTI]

    dependence analysis of back-gated graphene field-effect transistor terahertz responsivity at frequencies 0.003 X cm covered with 300-nm thermally grown SiO2 served as a substrate and back source and drain contacts were depos- ited on graphene by the electron beam evaporation. Fig. 1(a) shows

  6. Water Pentamer: Characterization of the Torsional-Puckering Manifold by Terahertz VRT Spectroscopy

    E-Print Network [OSTI]

    Cohen, Ronald C.

    Water Pentamer: Characterization of the Torsional-Puckering Manifold by Terahertz VRT Spectroscopy Heather A. Harker, Mark R. Viant, Frank N. Keutsch,§ Ernest A. Michael,| Ryan P. McLaughlin, and Richard J observation of this perturbation in the perdeuterated water pentamer, as well as the first observation

  7. Characterization of Graphene-based Nano-antennas in the Terahertz Band

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    Characterization of Graphene-based Nano-antennas in the Terahertz Band (Invited Paper) Ignacio and Communication Technology, KTH Royal Institute of Technology, 16640 Kista, Sweden Email: lemme@kth.se Abstract--Graphene communications at the nanoscale. Indeed, graphene- based nano-antennas just a few micrometers in size have been

  8. Controlling terahertz waves with meta-materials and photonic bandgap structures

    SciTech Connect (OSTI)

    Shchegolkov, Dmitry [Los Alamos National Laboratory; Azad, Abul [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Simakov, Evgenya I [Los Alamos National Laboratory

    2010-12-07T23:59:59.000Z

    We will describe research conducted at Los Alamos National Laboratory towards developing components for controlling terahertz waves. We employ meta-materials and, particularly, meta-films, as very compact absorbers for controlling quasioptical beams. We believe that dielectric photonic bandgap structures could replace ordinary metal waveguide devices at THz, since metal structures become extremely lossy in this frequency range.

  9. Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz radiation

    E-Print Network [OSTI]

    Van Driel, Henry M.

    Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz; published online 18 November 2005 Shift and injection currents are generated in the wurtzite semiconductors in the wurtzite structure. The largest shift currents are generated along the optical axis for light polarized

  10. Terahertz photoconductivity of Pb1-xSnxTe,,In... Dmitry Khokhlov,1,a

    E-Print Network [OSTI]

    Ganichev, Sergey

    of different materials, including explosives, etc.3­6 Development of detectors of la- ser radiation system-indium-doped Pb1-xSnxTe-can be implemented for detection of terahertz radiation yielding extremely- ductivity periodically quenched by short radiofrequency pulses. A remarkable feature is that this material

  11. Terahertz responsivity of field effect transistors versus their static channel conductivity and loading effects

    E-Print Network [OSTI]

    Levelut, Claire

    . Teppe,1 and W. Knap1 1 Laboratoire Charles Coulomb UMR 5221 and TERALAB, Universite´ Montpellier2 for terahertz imaging. This article gives prospects for electrical simulation of these transistors field is rectified like in square law detectors and a constant (dc) source-to-drain voltage appears

  12. Ratchet Effects Induced by Terahertz Radiation in Heterostructures with a Lateral Periodic Potential

    E-Print Network [OSTI]

    Ganichev, Sergey

    Ratchet Effects Induced by Terahertz Radiation in Heterostructures with a Lateral Periodic of the Seebeck ratchet effect. The effect is measured in semiconductor heterostructures with a one ratchet effect, we observe a photon helicity dependent response and propose a microscopic mechanism

  13. Application of Volume diffraction grating for TeraHertz lasing in Volume FEL (VFEL)

    E-Print Network [OSTI]

    V. G. Baryshevsky; K. G. Batrakov; V. I. Stolyarsky

    2002-09-06T23:59:59.000Z

    The generation of induced radiation in volume resonator formed by metal threads is considered. It is shown that using of such volume diffraction grating allows increasing of lasing efficiency in terahertz range. The requirements on beam and grating parameters are obtained.

  14. All-electric detection of the Stokes parameters of infrared and terahertz radiation

    E-Print Network [OSTI]

    Fominov, Yakov

    All-electric detection of the Stokes parameters of infrared and terahertz radiation S.D. Ganichev to measure radiation ellipticity use polarizers-analyzers or ellipsometers. Here we report on an all-electric detection of the laser radiation polarization state describing by the Stokes parameters. The method is based

  15. Spatiotemporal shaping of half-cycle terahertz pulses by diffraction through

    E-Print Network [OSTI]

    Stroud, Carlos R.

    demonstrate a simple quasi-optical technique for spatiotemporal shaping of half-cycle terahertz-radiation (such as GaAs, InP, or CdTe) or radiation-damaged silicon-on-sapphire. Generated carri- ers are rapidly of finite thickness Jake Bromage, Stojan Radic, G. P. Agrawal, and C. R. Stroud, Jr. The Institute of Optics

  16. Terahertz Sensor for Non-Contact Thickness and Quality Measurement of Automobile Paints of Varying Complexity

    E-Print Network [OSTI]

    Su, Ke; Shen, Yao-Chun; Zeitler, J. Axel

    2014-06-06T23:59:59.000Z

    to resolve coating layers down to a thickness of 18 $mu{hbox{m}}$ and was validated for both single- and multi-layer automobile paint samples. Results of the terahertz measurements were benchmarked against other techniques that are currently used for non...

  17. Vol. 11, No. 12/December 1994/J. Opt. Soc. Am. B 2457 Coherent control of terahertz emission and carrier

    E-Print Network [OSTI]

    Purdue University

    when the exciting optical fields are shaped in both amplitude and phase. Our shaping techniques include phase-locked pulse generation in a Michelson interferometer and pulse-train generation by phase state is determined by the exciting optical field. This phase can be lost by a variety of processes

  18. Single-cycle terahertz pulses with >0.2 V/A field amplitudes via coherent transition radiation

    E-Print Network [OSTI]

    Source (LCLS) free-electron laser,17 using electron bunches as short as 50 fs. We observe THz pulses at half maximum (FWHM), corresponding to peak currents of up to 7 kA. After being passed through the LCLS

  19. Studies on the switching speed effect of the phase shift keying in SLED for generating high power microwave

    E-Print Network [OSTI]

    Zhengfeng, Xiong; Jian, Yu; Huaibi, Chen; Hui, Ning

    2015-01-01T23:59:59.000Z

    SLAC energy doubler (SLED) type radio-frequency pulse compressors are widely used in large-scale particle accelerators for converting long-duration moderate-power input pulse into short-duration high-power output pulse. The phase shift keying (PSK) is one of the key components in SLED pulse compression systems. Performance of the PSK will influence the output characteristics of SLED, such as rise-time of the output pulse, the maximal peak power gain, and the energy efficiency. In this paper, high power microwave source based on power combining and pulse compression of conventional klystrons was introduced, the nonideal PSK with slow switching speed and without power output during the switching process were investigated, the experimental results with nonideal PSK agreed well with the analytical results.

  20. A Feasibility Analysis for the Design of A Low-Cost High-Power Energy Storage System

    E-Print Network [OSTI]

    Sekhon, Jasjeet S.

    A Feasibility Analysis for the Design of A Low-Cost High-Power Energy Storage System Travis Mc://www.funginstitute.berkeley.edu/sites/default/ les/EnergyStorageSystem.pdf May 3, 2014 130 Blum Hall #5580 Berkeley, CA 94720-5580 | (510) 664 of existing systems. Energy storage is a viable method for increasing the e ciency of a broad range of systems

  1. IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 13, NO. 2, MARCH 1998 213 Nonlinear-Carrier Control for High-Power-Factor

    E-Print Network [OSTI]

    IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 13, NO. 2, MARCH 1998 213 Nonlinear-Carrier Control´c, Member, IEEE Abstract-- In this paper, nonlinear-carrier (NLC) control is proposed for high-power on a 150-W flyback rectifier are presented. Index Terms--Current-mode control, high-power-factor recti

  2. System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform

    DOE Patents [OSTI]

    Caplan, Malcolm; Friedman, Herbert W.

    2005-07-19T23:59:59.000Z

    A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

  3. Research and Development of High-Power and High-Energy Electrochemical Storage Devices

    SciTech Connect (OSTI)

    No, author

    2014-04-30T23:59:59.000Z

    The accomplishments and technology progressmade during the U.S. Department of Energy (DOE) Cooperative Agreement No. DE-FC26- 05NT42403 (duration: July 11, 2005 through April 30, 2014, funded for $125 million in cost- shared research) are summarized in this Final Technical Report for a total of thirty-seven (37) collaborative programs organized by the United States Advanced Battery Consortium, LLC (USABC). The USABC is a partnership, formed in 1991, between the three U.S. domestic automakers Chrysler, Ford, and General Motors, to sponsor development of advanced high-performance batteries for electric and hybrid electric vehicle applications. The USABC provides a unique opportunity for developers to leverage their resources in combination with those of the automotive industry and the Federal government. This type of pre-competitive cooperation minimizes duplication of effort and risk of failure, and maximizes the benefits to the public of the government funds. A major goal of this program is to promote advanced battery development that can lead to commercialization within the domestic, and as appropriate, the foreign battery industry. A further goal of this program is to maintain a consortium that engages the battery manufacturers with the automobile manufacturers and other key stakeholders, universities, the National Laboratories, and manufacturers and developers that supply critical materials and components to the battery industry. Typically, the USABC defines and establishes consensus goals, conducts pre-competitive, vehicle-related research and development (R&D) in advanced battery technology. The R&D carried out by the USABC is an integral part of the DOE’s effort to develop advanced transportation technologies that will significantly improve fuel economy, comply with projected emissions and safety regulations, and use domestically produced fuels. The USABC advanced battery development plan has the following three focus areas: 1. Existing technology validation, implementation, and cost reduction. 2. Identification of the next viable technology with emphasis on the potential to meet USABC cost and operating temperature range goals. 3. Support high-risk, high-reward battery technology R&D. Specific to the Cooperative Agreement DE- FC26-05NT42403, addressing High-Energy and High Power Energy Storage Technologies, the USABC focus was on understanding and addressing the following factors (listed in priority of effort): • Cost: Reducing the current cost of lithium- ion batteries (currently about 2-3 times the FreedomCAR target ($20/kW). • Low Temperature Performance: Improving the discharge power and removing lithium plating during regenerative braking. • Calendar Life: Achieving 15-year life and getting accurate life prediction. • Abuse Tolerance: Developing a system level tolerance to overcharge, crush, and high temperature exposure. This Final Technical Report compilation is submitted in fulfillment of the subject Cooperative Agreement, and is intended to serve as a ready-reference for the outcomes of following eight categories of projects conducted by the USABC under award from the DOE’s Energy Efficiency and Renewable Energy ) Vehicle Technologies Program: USABC DoE Final Report – DoE Cooperative Agreement DE-FC26-95EE50425 8 Protected Information 1. Electric Vehicle (EV) (Section A of this report) 2. Hybrid Electric Vehicle (HEV) (Section B 3. Plug-In Hybrid Electric Vehicle (PHEV) (Section C) 4. Low-Energy Energy Storage Systems (LEESS) (Section D) 5. Technology Assessment Program (TAP) (Section E) 6. Ultracapacitors (Section F) 7. 12 Volt Start-Stop (Section G) 8. Separators (Section H) The report summarizes the main areas of activity undertaken in collaboration with the supplier community and the National Laboratories. Copies of the individual supplier final reports are available upon request. Using project gap analysis versus defined USABC goals in each area, the report documents known technology limits and provides direction on future areas of technology and performance needs for vehicle applicatio

  4. Terahertz inline wall thickness monitoring system for plastic pipe extrusion

    SciTech Connect (OSTI)

    Hauck, J., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Stich, D., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Heidemeyer, P., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Bastian, M., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de; Hochrein, T., E-mail: j.hauck@skz.de, E-mail: d.stich@skz.de, E-mail: p.heidemeyer@skz.de, E-mail: m.bastian@skz.de, E-mail: t.hochrein@skz.de [SKZ - German Plastics Center, Wuerzburg (Germany)

    2014-05-15T23:59:59.000Z

    Conventional and commercially available inline wall thickness monitoring systems for pipe extrusion are usually based on ultrasonic or x-ray technology. Disadvantages of ultrasonic systems are the usual need of water as a coupling media and the high damping in thick walled or foamed pipes. For x-ray systems special safety requirements have to be taken into account because of the ionizing radiation. The terahertz (THz) technology offers a novel approach to solve these problems. THz waves have many properties which are suitable for the non-destructive testing of plastics. The absorption of electrical isolators is typically very low and the radiation is non-ionizing in comparison to x-rays. Through the electromagnetic origin of the THz waves they can be used for contact free measurements. Foams show a much lower absorption in contrast to acoustic waves. The developed system uses THz pulses which are generated by stimulating photoconductive switches with femtosecond laser pulses. The time of flight of THz pulses can be determined with a resolution in the magnitude of several ten femtoseconds. Hence the thickness of an object like plastic pipes can be determined with a high accuracy by measuring the time delay between two reflections on materials interfaces e.g. at the pipe's inner and outer surface, similar to the ultrasonic technique. Knowing the refractive index of the sample the absolute layer thickness from the transit time difference can be calculated easily. This method in principle also allows the measurement of multilayer systems and the characterization of foamed pipes.

  5. Practical Witness for Electronic Coherences

    E-Print Network [OSTI]

    Allan S. Johnson; Joel Yuen-Zhou; Alán Aspuru-Guzik; Jacob J. Krich

    2014-08-13T23:59:59.000Z

    The origin of the coherences in two-dimensional spectroscopy of photosynthetic complexes remains disputed. Recently it has been shown that in the ultrashort-pulse limit, oscillations in a frequency-integrated pump-probe signal correspond exclusively to electronic coherences, and thus such experiments can be used to form a test for electronic vs. vibrational oscillations in such systems. Here we demonstrate a method for practically implementing such a test, whereby pump-probe signals are taken at several different pulse durations and used to extrapolate to the ultrashort-pulse limit. We present analytic and numerical results determining requirements for pulse durations and the optimal choice of pulse central frequency, which can be determined from an absorption spectrum. Our results suggest that for numerous systems the required experiment could be implemented by many ultrafast spectroscopy laboratories using pulses of tens of femtoseconds in duration. Such experiments could resolve the standing debate over the nature of coherences in photosynthetic complexes.

  6. Superposed Coherent and Squeezed Light

    E-Print Network [OSTI]

    Fesseha Kassahun

    2012-01-18T23:59:59.000Z

    We first calculate the mean photon number and quadrature variance of superposed coherent and squeezed light, following a procedure of analysis based on combining the Hamiltonians and using the usual definition for the quadrature variance of superposed light beams. This procedure of analysis leads to physically unjustifiable mean photon number of the coherent light and quadrature variance of the superposed light. We then determine both of these properties employing a procedure of analysis based on superposing the Q functions and applying a slightly modified definition for the quadrature variance of a pair of superposed light beams. We find the expected mean photon number of the coherent light and the quadrature variance of the superposed light. Moreover, the quadrature squeezing of the superposed output light turns out to be equal to that of the superposed cavity light.

  7. Coherent scattering from a free gas

    E-Print Network [OSTI]

    Sanders, Scott N.

    We investigate decoherence in atom interferometry due to scattering from a background gas and show that the supposition that residual coherence is due to near-forward scattering is incorrect. In fact, the coherent part is ...

  8. Hanbury Brown-Twiss Experiment with Coherent

    E-Print Network [OSTI]

    39 Chapter 2 Hanbury Brown-Twiss Experiment with Coherent Light This chapter was previously a theory that allows us #12;40 Hanbury Brown-Twiss Experiment with Coherent Light to construct processes

  9. Radiation trapping in coherent media

    E-Print Network [OSTI]

    A. B. Matsko; I. Novikova; M. O. Scully; G. R. Welch

    2001-01-31T23:59:59.000Z

    We show that the effective decay rate of Zeeman coherence, generated in a Rb87 vapor by linearly polarized laser light, increases significantly with the atomic density. We explain this phenomenon as the result of radiation trapping. Our study shows that radiation trapping must be taken into account to fully understand many electromagnetically induced transparency experiments with optically thick media.

  10. Constructing matrices with optimal block coherence

    E-Print Network [OSTI]

    Thompson, Andrew

    Constructing matrices with optimal block coherence Andrew Thompson (Duke University) Joint work · Background: · The subspace packing problem · An equivalent notion: block coherence · Who is interested in this? #12;Outline · Background: · The subspace packing problem · An equivalent notion: block coherence

  11. Characterization of plasma expansion dynamics in a high power diode with a carbon-fiber-aluminum cathode

    SciTech Connect (OSTI)

    Ju, J.-C., E-mail: jujinchuan@126.com [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Laboratoire de Physique des Gaz et des Plasmas, CNRS-Université Paris-Sud, Orsay 91405 (France); Liu, L.; Cai, D. [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-06-09T23:59:59.000Z

    Thermal plasma expansion is characterised during the operation of a high power diode with an explosive emission carbon-fiber-aluminum cathode driven by a 250?kV, 150?ns accelerating pulse. It is found that a quasi-stationary state of plasma expansion is obtained during the main part of the accelerating pulse and the whole plasma expansion exhibits an “U”-shape velocity evolution. A theoretical model describing the dynamics of plasma expansion is developed, which indicates that the plasma expansion velocity is determined by equilibrium between the diode current density and plasma thermal electron current density.

  12. Evaporation-assisted high-power impulse magnetron sputtering: The deposition of tungsten oxide as a case study

    SciTech Connect (OSTI)

    Hemberg, Axel; Dauchot, Jean-Pierre; Snyders, Rony; Konstantinidis, Stephanos [Materia Nova Research Center-Parc Initialis, 1, Avenue Copernic, B-7000 Mons, Belgium and Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Center-Parc Initialis, 1, Avenue Copernic, B-7000 Mons (Belgium) and Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface, CIRMAP, Universite de Mons-20, Place du Parc, B-7000 Mons (Belgium)

    2012-07-15T23:59:59.000Z

    The deposition rate during the synthesis of tungsten trioxide thin films by reactive high-power impulse magnetron sputtering (HiPIMS) of a tungsten target increases, above the dc threshold, as a result of the appropriate combination of the target voltage, the pulse duration, and the amount of oxygen in the reactive atmosphere. This behavior is likely to be caused by the evaporation of the low melting point tungsten trioxide layer covering the metallic target in such working conditions. The HiPIMS process is therefore assisted by thermal evaporation of the target material.

  13. Absorption coefficient of aluminum near the critical point and the consequences on high-power nanosecond laser ablation

    SciTech Connect (OSTI)

    Wu Benxin; Shin, Yung C. [Center for Laser-based Manufacturing, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2006-09-11T23:59:59.000Z

    During nanosecond laser ablation, the absorption coefficient determines the laser energy deposition in the target, the accurate knowledge of which near the material critical point is crucial for understanding the fundamental physics of high-power nanosecond laser ablation. In this letter, the absorption coefficient of aluminum near the critical point is calculated through the Drude model based on the measured electrical conductivity data, and its effect on laser ablation is investigated numerically using a heat transfer model. The result supports the experimental observations that phase explosion occurs for the ablation of aluminum by sufficiently intense laser pulses, and the model predicted phase explosion threshold is consistent with experimental measurements.

  14. The development of low cost LiFePO4-based high power lithium-ion batteries

    SciTech Connect (OSTI)

    Shim, Joongpyo; Sierra, Azucena; Striebel, Kathryn A.

    2003-11-25T23:59:59.000Z

    The cycling performance of low-cost LiFePO4-based high-power lithium-ion cells was investigated and the components were analyzed after cycling to determine capacity fade mechanisms. Pouch type LiFePO4/natural graphite cells were assembled and evaluated by constant C/2 cycling, pulse-power and impedance measurements. From post-test electrochemical analysis after cycling, active materials, LiFePO4 and natural graphite, showed no degradation structurally or electrochemically. The main reasons for the capacity fade of cell were lithium inventory loss by side reaction and possible lithium deposition on the anode.

  15. Ultrafast terahertz-induced response of GeSbTe phase-change materials Michael J. Shu,1,2,a)

    E-Print Network [OSTI]

    Ultrafast terahertz-induced response of GeSbTe phase-change materials Michael J. Shu,1,2,a) Peter-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub of these materials is important for predicting the field-driven heating and phase-change behavior. However

  16. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    SciTech Connect (OSTI)

    Shu, Michael J. [Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zalden, Peter [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Chen, Frank [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Weems, Ben [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Chatzakis, Ioannis [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Hoffmann, Matthias C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, 52056 Aachen (Germany); JARA–Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen (Germany); Lindenberg, Aaron M., E-mail: aaronl@stanford.edu [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23T23:59:59.000Z

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200?kV/cm.

  17. Preparation of room temperature terahertz detector with lithium tantalate crystal and thin film

    SciTech Connect (OSTI)

    Wang, Jun, E-mail: ueoewj@gmail.com; Gou, Jun; Li, Weizhi [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2014-02-15T23:59:59.000Z

    Research on room temperature terahertz (THz) detector is essential for promoting the application of THz science and technology. Both lithium tantalate crystal (LiTaO{sub 3}) and lithium tantalate thin film were used to fabricate the THz detector in this paper. Polishing process were used to reduce the thickness of LiTaO{sub 3} crystal slice by chemical mechanical polishing techniques and an improved sol-gel process was used to obtain high concentration LiTaO{sub 3} precursor solution to fabricate LiTaO{sub 3} thin film. Three dimension models of two THz detectors were set up and the temperature increasing map of two devices were simulated using finite element method. The lowest noise equivalent power value for terahertz detector using pyroelectric material reaches 6.8 × 10{sup ?9} W at 30 Hz operating frequency, which is suitable for THz imaging application.

  18. Fundamental Studies and Development of III-N Visible LEDs for High-Power Solid-State Lighting Applications

    SciTech Connect (OSTI)

    Dupuis, Russell

    2012-02-29T23:59:59.000Z

    The goal of this program is to understand in a fundamental way the impact of strain, defects, polarization, and Stokes loss in relation to unique device structures upon the internal quantum efficiency (IQE) and efficiency droop (ED) of III-nitride (III-N) light-emitting diodes (LEDs) and to employ this understanding in the design and growth of high-efficiency LEDs capable of highly-reliable, high-current, high-power operation. This knowledge will be the basis for our advanced device epitaxial designs that lead to improved device performance. The primary approach we will employ is to exploit new scientific and engineering knowledge generated through the application of a set of unique advanced growth and characterization tools to develop new concepts in strain-, polarization-, and carrier dynamics-engineered and low-defect materials and device designs having reduced dislocations and improved carrier collection followed by efficient photon generation. We studied the effects of crystalline defect, polarizations, hole transport, electron-spillover, electron blocking layer, underlying layer below the multiplequantum- well active region, and developed high-efficiency and efficiency-droop-mitigated blue LEDs with a new LED epitaxial structures. We believe new LEDs developed in this program will make a breakthrough in the development of high-efficiency high-power visible III-N LEDs from violet to green spectral region.

  19. Calculational analysis of structural activation induced by 20-100 MeV proton beam loss in high-power linear accelerators 

    E-Print Network [OSTI]

    Lee, Stacey Kirsten

    1994-01-01T23:59:59.000Z

    to obtain dose rate estimates at several locations near the accelerator. To perform these calculations, simplified computer models were developed from detailed engineering drawings of a typical high-power accelerator design. This research focused on the 20...

  20. Quantizations on the circle and coherent states

    E-Print Network [OSTI]

    Chadzitaskos, G; Tolar, J

    2012-01-01T23:59:59.000Z

    We present a possible construction of coherent states on the unit circle as configuration space. Our approach is based on Borel quantizations on S^1 including the Aharonov-Bohm type quantum description. The coherent states are constructed by Perelomov's method as group related coherent states generated by Weyl operators on the quantum phase space Z x S^1. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction we use the analogy with our quantization and coherent states over a finite periodic chain where the quantum phase space was Z_M x Z_M. The coherent states constructed in this work are shown to satisfy the resolution of unity. To compare them with canonical coherent states, also some of their further properties are studied demonstrating similarities as well as substantial differences.

  1. Calculational analysis of structural activation induced by 20-100 MeV proton beam loss in high-power linear accelerators

    E-Print Network [OSTI]

    Lee, Stacey Kirsten

    1994-01-01T23:59:59.000Z

    fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1994 Major Subject: Nuclear Engineering CALCULATIONAL ANALYSIS OF STRUCTURAL ACTIVATION INDUCED BY 20-100 MEV PROTON BEAM LOSS IN HIGH-POWER LINEAR ACCELERATORS A Thesis...) Carl A. Beard (Member) / John . Poston (Head of Department) August 1994 Major Subject: Nuclear Engineering ABSTRACT Calculational Analysis of Structural Activation Induced by 20-100 MeV Proton Beam Loss in High-Power Linear Accelerators. (August...

  2. Quantum learning of coherent states

    E-Print Network [OSTI]

    Gael Sentís; Madalin Guta; Gerardo Adesso

    2014-10-31T23:59:59.000Z

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian estimation measurements. Our results show that, even in absence of entanglement, collective quantum measurements yield an enhancement in the readout of classical information, which is particularly relevant in the operating regime of low-energy signals.

  3. High damage-resistant Mo mirror for high-power TEA CO/sub 2/ laser systems

    SciTech Connect (OSTI)

    Ichikawa, Y.; Yoshida, K.; Tsunawaki, Y.; Yamanaka, M.; Yamanaka, T.; Yamanaka, C.; Okamoto, H.; Matsusue, N.; Kitajima, K.

    1987-09-01T23:59:59.000Z

    A high-purity molybdenum (Mo) mirror was developed by an electron-beam melting method (e.b.m. Mo mirror). For high-power TEA CO/sub 2/ laser, the e.b.m. Mo mirror has two to four times higher surface damage threshold than that of an Au-coated glass mirror and three times longer lifetime than that of a powder metallurgy Mo mirror (p.m. Mo mirror) when laser energy density lower than 60 J/cm/sup 2/ was irradiated with a 0.5-pps repetition rate. It was found that the difference between the e.b.m. Mo mirror and the p.m. Mo mirror at the laser-damage threshold was due to the five surface without voids and the small amount of impurities.

  4. Current-voltage-time characteristics of the reactive Ar/N{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect (OSTI)

    Magnus, F.; Sveinsson, O. B.; Olafsson, S. [Science Institute, University of Iceland, Dunhaga 3, Reykjavik IS-107 (Iceland); Gudmundsson, J. T. [Science Institute, University of Iceland, Dunhaga 3, Reykjavik IS-107 (Iceland); University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China)

    2011-10-15T23:59:59.000Z

    The discharge current and voltage waveforms have been measured in a reactive high power impulse magnetron sputtering (HiPIMS) Ar/N{sub 2} discharge with a Ti target for 400 {mu}s long pulses. We observe that the current waveform in the reactive Ar/N{sub 2} HiPIMS discharge is highly dependent on the pulse repetition frequency, unlike the non-reactive Ar discharge. The current is found to increase significantly as the frequency is lowered. This is attributed to an increase in the secondary electron emission yield during the self-sputtering phase, when the nitride forms on the target at low frequencies. In addition, self-sputtering runaway occurs at lower discharge voltages when nitrogen is added to the discharge. This illustrates the crucial role of self-sputtering in the behavior of the reactive HiPIMS discharge.

  5. Time resolved measurement of film growth during reactive high power pulsed magnetron sputtering (HIPIMS) of titanium nitride

    E-Print Network [OSTI]

    Mitschker, Felix; Benedikt, Jan; Maszl, Christian; von Keudell, Achim

    2013-01-01T23:59:59.000Z

    The growth rate during reactive high power pulsed magnetron sputtering (HIPIMS) of titanium nitride is measured with a temporal resolution of up to 25 us using a rotating shutter concept. According to that concept a 200 um slit is rotated in front of the substrate synchronous with the HIPIMS pulses. Thereby, the growth flux is laterally distributed over the substrate. By measuring the resulting deposition profile with profilometry and with x-ray photoelectron spectroscopy, the temporal variation of the titanium and nitrogen growth flux per pulse is deduced. The analysis reveals that film growth occurs mainly during a HIPIMS pulse, with the growth rate following the HIPIMS phases ignition, current rise, gas rarefaction, plateau and afterglow. The growth fluxes of titanium and nitrogen follow slightly different behaviors with titanium dominating at the beginning of the HIPIMS pulse and nitrogen at the end of the pulse. This is explained by the gas rarefaction effect resulting in a dense initial metal plasma and...

  6. 2012 ARPA-E Energy Innovation Summit: Profiling Foro Energy: High Power Lasers - Long Distances (Performer Video)

    ScienceCinema (OSTI)

    None Available

    2012-03-21T23:59:59.000Z

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video from Foro Energy are Joel Moxley, Founder and CEO, Mark Zediker, Founder and CTO, and Paul Deutch, President and COO. Steven Chu, Secretary of Energy, also appears briefly in this video to praise the accomplishment of a high powered laser that can transmit that power long distances for faster and more powerful drilling of geothermal, oil, and gas wells.

  7. DEPOSITION OF NIOBIUM AND OTHER SUPERCONDUCTING MATERIALS WITH HIGH POWER IMPULSE MAGNETRON SPUTTERING: CONCEPT AND FIRST RESULTS

    SciTech Connect (OSTI)

    High Current Electronics Institute, Tomsk, Russia; Anders, Andre; Mendelsberg, Rueben J.; Lim, Sunnie; Mentink, Matthijs; Slack, Jonathan L.; Wallig, Joseph G.; Nollau, Alexander V.; Yushkov, Georgy Yu.

    2011-07-24T23:59:59.000Z

    Niobium coatings on copper cavities have been considered as a cost-efficient replacement of bulk niobium RF cavities, however, coatings made by magnetron sputtering have not quite lived up to high expectations due to Q-slope and other issues. High power impulse magnetron sputtering (HIPIMS) is a promising emerging coatings technology which combines magnetron sputtering with a pulsed power approach. The magnetron is turned into a metal plasma source by using very high peak power density of ~ 1 kW/cm{sup 2}. In this contribution, the cavity coatings concept with HIPIMS is explained. A system with two cylindrical, movable magnetrons was set up with custom magnetrons small enough to be inserted into 1.3 GHz cavities. Preliminary data on niobium HIPIMS plasma and the resulting coatings are presented. The HIPIMS approach has the potential to be extended to film systems beyond niobium, including other superconducting materials and/or multilayer systems.

  8. Numerical simulations of output pulse extraction from a high-power microwave compressor with a plasma switch

    SciTech Connect (OSTI)

    Shlapakovski, Anatoli; Beilin, Leonid; Bliokh, Yuri; Donskoy, Moshe; Krasik, Yakov E. [Physics Department, Technion, Haifa 32000 (Israel); Hadas, Yoav [Department of Applied Physics, Rafael, PO Box 2250, Haifa 31021 (Israel); Schamiloglu, Edl [Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-05-07T23:59:59.000Z

    Numerical simulations of the process of electromagnetic energy release from a high-power microwave pulse compressor comprising a gas-filled cavity and interference switch were carried out. A microwave plasma discharge in a rectangular waveguide H-plane tee was modeled with the use of the fully electromagnetic particle-in-cell code MAGIC. The gas ionization, plasma evolution, and interaction with RF fields accumulated within the compressor were simulated using different approaches provided by the MAGIC code: particle-in-cell approach accounting for electron-neutral collisions, gas conductivity model based on the concept of mobility, and hybrid modeling. The dependences of the microwave output pulse peak power and waveform on parameters that can be controlled in experiments, such as an external ionization rate, RF field amplitude, and background gas pressure, were investigated.

  9. 2012 ARPA-E Energy Innovation Summit: Profiling Foro Energy: High Power Lasers - Long Distances (Performer Video)

    SciTech Connect (OSTI)

    None Available

    2012-02-28T23:59:59.000Z

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. A few videos were selected for showing during the Summit to attendees. These 'performer videos' highlight innovative research that is ongoing and related to the main topics of the Summit's sessions. Featured in this video from Foro Energy are Joel Moxley, Founder and CEO, Mark Zediker, Founder and CTO, and Paul Deutch, President and COO. Steven Chu, Secretary of Energy, also appears briefly in this video to praise the accomplishment of a high powered laser that can transmit that power long distances for faster and more powerful drilling of geothermal, oil, and gas wells.

  10. High power impulse magnetron sputtering and related discharges: scalable plasma sources for plasma-based ion implantation and deposition

    SciTech Connect (OSTI)

    Anders, Andre

    2009-09-01T23:59:59.000Z

    High power impulse magnetron sputtering (HIPIMS) and related self-sputtering techniques are reviewed from a viewpoint of plasma-based ion implantation and deposition (PBII&D). HIPIMS combines the classical, scalable sputtering technology with pulsed power, which is an elegant way of ionizing the sputtered atoms. Related approaches, such as sustained self-sputtering, are also considered. The resulting intense flux of ions to the substrate consists of a mixture of metal and gas ions when using a process gas, or of metal ions only when using `gasless? or pure self-sputtering. In many respects, processing with HIPIMS plasmas is similar to processing with filtered cathodic arc plasmas, though the former is easier to scale to large areas. Both ion implantation and etching (high bias voltage, without deposition) and thin film deposition (low bias, or bias of low duty cycle) have been demonstrated.

  11. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOE Patents [OSTI]

    Veligdan, James T. (Manorville, NY)

    1994-01-01T23:59:59.000Z

    An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90.degree. angle of incidence.

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

    SciTech Connect (OSTI)

    Guo, Jiquan; /SLAC

    2009-03-20T23:59:59.000Z

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

  13. Apparatus for generating partially coherent radiation

    DOE Patents [OSTI]

    Naulleau, Patrick P.

    2004-09-28T23:59:59.000Z

    The effective coherence of an undulator beamline can be tailored to projection lithography requirements by using a simple single moving element and a simple stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (i) source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence; (ii) a reflective surface that receives incident radiation from said source; (iii) means for moving the reflective surface through a desired range of angles in two dimensions wherein the rate of the motion is fast relative to integration time of said image processing system; and (iv) a condenser optic that re-images the moving reflective surface to the entrance plane of said image processing system, thereby, making the illumination spot in said entrance plane essentially stationary.

  14. Does coherence enhance transport in photosynthesis?

    E-Print Network [OSTI]

    Ivan Kassal; Joel Yuen-Zhou; Saleh Rahimi-Keshari

    2012-10-18T23:59:59.000Z

    Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding incoherent processes.

  15. Does coherence enhance transport in photosynthesis?

    E-Print Network [OSTI]

    Kassal, Ivan; Rahimi-Keshari, Saleh

    2012-01-01T23:59:59.000Z

    Recent observations of coherence in photosynthetic complexes have led to the question of whether quantum effects can occur in vivo, not under femtosecond laser pulses but in incoherent sunlight and at steady state, and, if so, whether the coherence explains the high exciton transfer efficiency. We distinguish several types of coherence and show that although some photosynthetic pathways are partially coherent processes, photosynthesis in nature proceeds through stationary states. This distinction allows us to rule out several mechanisms of transport enhancement in sunlight. In particular, although they are crucial for understanding exciton transport, neither wavelike motion nor microscopic coherence, on their own, enhance the efficiency. By contrast, two partially coherent mechanisms---ENAQT and supertransfer---can enhance transport even in sunlight and thus constitute motifs for the optimisation of artificial sunlight harvesting. Finally, we clarify the importance of ultrafast spectroscopy in understanding i...

  16. Dispersion retrieval from multi-level ultra-deep reactive-ion-etched microstructures for terahertz slow-wave circuits

    SciTech Connect (OSTI)

    Baik, Chan-Wook, E-mail: cw.baik@samsung.com; Young Ahn, Ho; Kim, Yongsung; Lee, Jooho; Hong, Seogwoo; Hee Choi, Jun; Kim, Sunil; Hun Lee, Sang; Min Kim, Jong; Hwang, Sungwoo [Samsung Advanced Institute of Technology, Yongin 446-712 (Korea, Republic of); Yeon Jun, So; Yu, SeGi [Department of Physics, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Lawrence Ives, R. [Calabazas Creek Research, Inc., San Mateo, California 94404-1010 (United States)

    2014-01-13T23:59:59.000Z

    A multi-level microstructure is proposed for terahertz slow-wave circuits, with dispersion relation retrieved by scattering parameter measurements. The measured return loss shows strong resonances above the cutoff with negligible phase shifts compared with finite element analysis. Splitting the circuit into multi levels enables a low aspect ratio configuration that alleviates the loading effect of deep-reactive-ion etching on silicon wafers. This makes it easier to achieve flat-etched bottom and smooth sidewall profiles. The dispersion retrieved from the measurement, therefore, corresponds well to the theoretical estimation. The result provides a straightforward way to the precise determination of dispersions in terahertz vacuum electronics.

  17. Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma

    SciTech Connect (OSTI)

    Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)

    2014-06-15T23:59:59.000Z

    A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

  18. Decoherence of multimode thermal squeezed coherent states

    SciTech Connect (OSTI)

    Yeh, L.

    1992-08-14T23:59:59.000Z

    It is well known that any multimode positive definite quadratic Hamiltonian can be transformed into a hamiltonian of uncoupled harmonic oscillators. Based on this theorem, the multimode thermal squeezed coherent states are constructed in terms of density operators. Decoherence of multimode thermal squeezed coherent states in investigated via the characteristic function and it is shown that the decohered (reduced) states are still thermal squeezed coherent states in general.

  19. Coherent states for the nonlinear harmonic oscillator

    SciTech Connect (OSTI)

    Ghosh, Subir [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108 (India)

    2012-06-15T23:59:59.000Z

    Wave packets for the quantum nonlinear oscillator are considered in the generalized coherent state framework. To first order in the nonlinearity parameter the coherent state behaves very similar to its classical counterpart. The position expectation value oscillates in a simple harmonic manner. The energy-momentum uncertainty relation is time independent as in a harmonic oscillator. Various features (such as the squeezed state nature) of the coherent state have been discussed.

  20. Optimization Online - On the Coherent Risk Measure ...

    E-Print Network [OSTI]

    KEREM UGURLU

    2014-11-25T23:59:59.000Z

    Nov 25, 2014 ... Abstract: We give a complete characterization of both comonotone and not comonotone coherent risk measures in the discrete finite probability ...

  1. Influence of coherent Raman scattering on coherent population trapping in atomic sodium vapor

    SciTech Connect (OSTI)

    Wong, Vincent; Bennink, Ryan S.; Marino, Alberto M.; Boyd, Robert W.; Stroud, C.R. Jr.; Narducci, F.A. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); EO Sensors Division, Naval Air Systems Command, Patuxent River, Maryland 20670 (United States)

    2004-11-01T23:59:59.000Z

    We study how coherent Stokes and anti-Stokes Raman scattering influence coherent population trapping. In an experiment using an atomic sodium vapor cell we observe induced transparency, induced absorption, and gain features, all of subnatural linewidth. The electromagnetically induced resonance is a peak or a dip depending on which side of the optical transition the fields are tuned to, and thus whether coherent anti-Stokes Raman scattering or coherent Stokes Raman scattering is the dominant process.

  2. Coherent Control of Quantum Matter

    SciTech Connect (OSTI)

    Cavalleri, Andrea (Max Planck Institute) [Max Planck Institute

    2011-10-05T23:59:59.000Z

    This talk addresses some recent work aimed at controlling the low-lying electrodynamics of quantum solids using strong field transients. The excitation of selected vibrational resonances to manipulate the many-body physics of one dimensional Mott Hubbard Insulators and to perturb competing orders in High-Tc superconductors is also covered. Finally, the speaker shows how the electrodynamics of layered superconductors can be driven through the orderparameter phase gradient, demonstrating ultrafast transistor action in a layered superconductor. Advances in the use of coherent optics, from tabletop sources to THz and x-ray free-electron lasers are also discussed.

  3. Coherent instabilities in random lasers

    SciTech Connect (OSTI)

    Andreasen, Jonathan; Sebbah, Patrick; Vanneste, Christian [Laboratoire de Physique de la Matiere Condensee, CNRS UMR 6622, Universite de Nice-Sophia Antipolis, Parc Valrose, F-06108, Nice Cedex 02 (France)

    2011-08-15T23:59:59.000Z

    A numerical study is presented of random lasers as a function of the pumping rate above the threshold for lasing. Depending on the leakiness of the system resonances, which is typically larger in random lasers compared to conventional lasers, we observe that the stationary lasing regime becomes unstable above a second threshold. Coherent instabilities are observed as self pulsation at a single frequency of the output intensity, population inversion, as well as the atomic polarization. We find these Rabi oscillations have the same frequency everywhere in the random laser despite the fact that the field intensity strongly depends on the spatial location.

  4. Coherent Inc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model, clickInformationNew York: EnergyCoeur d Alene Fiber FuelsCoherent Inc Jump

  5. Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

    SciTech Connect (OSTI)

    Li, Jiang; Shi, Junkai; Xu, Baozhong; Xing, Qirong; Wang, Chingyue [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); Chai, Lu, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn; Liu, Bowen; Hu, Minglie; Li, Yanfeng, E-mail: lu-chai@tju.edu.cn, E-mail: yanfengli@tju.edu.cn [Ultrafast Laser Laboratory, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin 300072 (China); MOEMS Key Laboratory (Ministry of Education), Tianjin University, Tianjin 300072 (China); Fedotov, Andrey B. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Zheltikov, Aleksei M. [Physics Department, Russian Quantum Center, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States)

    2014-01-20T23:59:59.000Z

    A chirp-tunable femtosecond 10?W, 42?MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040?nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources.

  6. Tunable coherent radiation at soft X-ray wavelengths: Generation and interferometric applications

    SciTech Connect (OSTI)

    Rosfjord, Kristine Marie

    2004-07-01T23:59:59.000Z

    The availability of high power, spectrally and spatially coherent soft x-rays (SXR) would facilitate a wide variety of experiments as this energy region covers the primary resonances of many magnetic and biological materials. Specifically, there are the carbon and oxygen K-edges that are critical for biological imaging in the water window and the L-edges of iron, nickel, and cobalt for which imaging and scattering studies can be performed. A new coherent soft X-ray branchline at the Advanced Light Source has begun operation (beamline 12.0.2). Using the third harmonic from an 8 cm period undulator, this branch delivers coherent soft x-rays with photon energies ranging from 200eV to 1keV. This branchline is composed of two sub-branches one at 14X demagnification and the other 8X demagnification. The former is optimized for use at 500eV and the latter at 800eV. Here the expected power from the third harmonic of this undulator and the beamline design and characterization is presented. The characterization includes measurements on available photon flux as well as a series of double pinhole experiments to determine the coherence factor with respect to transverse distance. The first high quality Airy patterns at SXR wavelengths are created with this new beamline. The operation of this new beamline allows for interferometry to be performed in the SXR region. Here an interferometric experiment designed to directly determine the index of refraction of a material under test is performed. Measurements are first made in the EUV region using an established beamline (beamline12.0.1) to measure silicon, ruthenium and tantalum silicon nitride. This work is then extended to the SXR region using beamline 12.0.2 to test chromium and vanadium.

  7. Optical coherence domain reflectometry guidewire

    DOE Patents [OSTI]

    Colston, Billy W. (Livermore, CA); Everett, Matthew (Pleasanton, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis (Moss Beach, CA)

    2001-01-01T23:59:59.000Z

    A guidewire with optical sensing capabilities is based on a multiplexed optical coherence domain reflectometer (OCDR), which allows it to sense location, thickness, and structure of the arterial walls or other intra-cavity regions as it travels through the body during minimally invasive medical procedures. This information will be used both to direct the guidewire through the body by detecting vascular junctions and to evaluate the nearby tissue. The guidewire contains multiple optical fibers which couple light from the proximal to distal end. Light from the fibers at the distal end of the guidewire is directed onto interior cavity walls via small diameter optics such as gradient index lenses and mirrored corner cubes. Both forward viewing and side viewing fibers can be included. The light reflected or scattered from the cavity walls is then collected by the fibers, which are multiplexed at the proximal end to the sample arm of an optical low coherence reflectometer. The guidewire can also be used in nonmedical applications.

  8. Invited Article: An integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument

    SciTech Connect (OSTI)

    Kühne, P., E-mail: kuehne@huskers.unl.edu; Schubert, M., E-mail: schubert@engr.unl.edu; Hofmann, T., E-mail: thofmann@engr.unl.edu [Department of Electrical Engineering and Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Herzinger, C. M., E-mail: cherzinger@jawoollam.com; Woollam, J. A., E-mail: jwoollam@jawoollam.com [J. A. Woollam Co., Inc., 645 M Street, Suite 102, Lincoln, Nebraska 68508-2243 (United States)

    2014-07-15T23:59:59.000Z

    We report on the development of the first integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, covering an ultra wide spectral range from 3 cm{sup ?1} to 7000 cm{sup ?1} (0.1–210 THz or 0.4–870 meV). The instrument comprises four sub-systems, where the magneto-cryostat-transfer sub-system enables the usage of the magneto-cryostat sub-system with the mid-infrared ellipsometer sub-system, and the far-infrared/terahertz ellipsometer sub-system. Both ellipsometer sub-systems can be used as variable angle-of-incidence spectroscopic ellipsometers in reflection or transmission mode, and are equipped with multiple light sources and detectors. The ellipsometer sub-systems are operated in polarizer-sample-rotating-analyzer configuration granting access to the upper left 3 × 3 block of the normalized 4 × 4 Mueller matrix. The closed cycle magneto-cryostat sub-system provides sample temperatures between room temperature and 1.4 K and magnetic fields up to 8 T, enabling the detection of transverse and longitudinal magnetic field-induced birefringence. We discuss theoretical background and practical realization of the integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, as well as acquisition of optical Hall effect data and the corresponding model analysis procedures. Exemplarily, epitaxial graphene grown on 6H-SiC, a tellurium doped bulk GaAs sample and an AlGaN/GaN high electron mobility transistor structure are investigated. The selected experimental datasets display the full spectral, magnetic field and temperature range of the instrument and demonstrate data analysis strategies. Effects from free charge carriers in two dimensional confinement and in a volume material, as well as quantum mechanical effects (inter-Landau-level transitions) are observed and discussed exemplarily.

  9. Coherence in natural language : data structures and applications

    E-Print Network [OSTI]

    Wolf, Florian, 1975-

    2005-01-01T23:59:59.000Z

    (cont.) baseline, and that some coherence-based approaches best predict the human data. However, coherence-based algorithms that operate on trees did not perform as well as coherence-based algorithms that operate on more ...

  10. Voltage-tunable terahertz and infrared photodetectors based on double-graphene-layer structures

    SciTech Connect (OSTI)

    Ryzhii, V., E-mail: v-ryzhii@riec.tohoku.ac.jp [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Aleshkin, V. Ya.; Dubinov, A. A. [Institute for Physics of Microstructures of Russian Academy of Sciences, and Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States); Shur, M. S. [Department of Electrical, Electronics, and System Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2014-04-21T23:59:59.000Z

    We propose and theoretically substantiate the concept of terahertz and infrared photodetectors using the resonant radiative transitions between graphene layers (GLs) in double-GL structures. The calculated absorption spectrum and the spectral characteristics of the photodetector responsivity exhibit sharp resonant maxima at the photon energies in a wide range. The resonant maxima can be tuned by the applied voltage. We compare the photodetector responsivity with that of the GL p-i-n photodiodes and quantum-well infrared photodetectors. Weak temperature dependences of the photocurrent and dark current enable the effective operation of the proposed photodetector at room temperature.

  11. Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses

    SciTech Connect (OSTI)

    Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

    2013-05-13T23:59:59.000Z

    Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

  12. Heating and cooling of a two-dimensional electron gas by terahertz radiation

    SciTech Connect (OSTI)

    Budkin, G. V.; Tarasenko, S. A., E-mail: tarasenko@coherent.ioffe.ru [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

    2011-04-15T23:59:59.000Z

    The absorption of terahertz radiation by free charge carriers in n-type semiconductor quantum wells accompanied by the interaction of electrons with acoustic and optical phonons is studied. It is shown that intrasubband optical transitions can cause both heating and cooling of the electron gas. The cooling of charge carriers occurs in a certain temperature and radiation frequency region where light is most efficiently absorbed due to intrasubband transitions with emission of optical phonons. In GaAs quantum wells, the optical cooling of electrons occurs most efficiently at liquid nitrogen temperatures, while cooling is possible even at room temperature in GaN heterostructures.

  13. Fabrication, Inspection, and Test Plan for the Advanced Test Reactor (ATR) High-Power Mixed-Oxide (MOX) Fuel Irradiation Project

    SciTech Connect (OSTI)

    Wachs, G. W.

    1998-09-01T23:59:59.000Z

    The Department of Energy (DOE) Fissile Disposition Program (FMDP) has announced that reactor irradiation of Mixed-Oxide (MOX) fuel is one of the preferred alternatives for disposal of surplus weapons-usable plutonium (Pu). MOX fuel has been utilized domestically in test reactors and on an experimental basis in a number of Commercial Light Water Reactors (CLWRs). Most of this experience has been with Pu derived from spent low enriched uranium (LEU) fuel, known as reactor grade (RG) Pu. The High-Power MOX fuel test will be irradiated in the Advanced Test Reactor (ATR) to provide preliminary data to demonstrate that the unique properties of surplus weapons-derived or weapons-grade (WG) plutonium (Pu) do not compromise the applicability of this MOX experience base. The purpose of the high-power experiment, in conjunction with the currently ongoing average-power experiment at the ATR, is to contribute new information concerning the response of WG plutonium under more severe irradiation conditions typical of the peak power locations in commercial reactors. In addition, the high-power test will contribute experience with irradiation of gallium-containing fuel to the database required for resolution of generic CLWR fuel design issues. The distinction between "high-power" and "average-power" relates to the position within the nominal CLWR core. The high-power test project is subject to a number of requirements, as discussed in the Fissile Materials Disposition Program Light Water Reactor Mixed Oxide Fuel Irradiation High-Power Test Project Plan (ORNL/MD/LTR-125).

  14. Coherent Manipulation of Coupled Electron Spins in

    E-Print Network [OSTI]

    Petta, Jason

    to control quantum systems in the solid state is a major challenge of modern condensed-matter physics (5, 6. Gossard3 We demonstrated coherent control of a quantum two-level system based on two-electron spin states) based on two-electron spin states (14) and demonstrate coherent control of this system through the use

  15. Can Natural Sunlight Induce Coherent Exciton Dynamics?

    E-Print Network [OSTI]

    Jan Olšina; Arend G. Dijkstra; Chen Wang; Jianshu Cao

    2014-08-21T23:59:59.000Z

    Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, this sub-picosecond time-scale is long enough for light-harvesting systems to establish static coherence, which plays a crucial role in efficient energy transfer. Further, a relationship is established between the non-equilibrium steady-state induced by the sunlight and the coherent dynamics initiated from the ground state by a laser $\\delta$-pulse, thereby making a direct connection between incoherent sunlight excitation and ultrafast spectroscopy.

  16. Coherent state quantization of paragrassmann algebras

    E-Print Network [OSTI]

    M. El Baz; R. Fresneda; J. P. Gazeau; Y. Hassouni

    2011-12-30T23:59:59.000Z

    By using a coherent state quantization of paragrassmann variables, operators are constructed in finite Hilbert spaces. We thus obtain in a straightforward way a matrix representation of the paragrassmann algebra. This algebra of finite matrices realizes a deformed Weyl-Heisenberg algebra. The study of mean values in coherent states of some of these operators lead to interesting conclusions.

  17. The Fidelity and Trace Norm Distances for Quantifying Coherence

    E-Print Network [OSTI]

    Lian-He Shao; Zhengjun Xi; Heng Fan; Yongming Li

    2014-10-30T23:59:59.000Z

    We investigate the coherence measures induced by fidelity and trace norm, based on the recent proposed coherence quantification in [Phys. Rev. Lett. 113, 140401, 2014]. We show that the fidelity of coherence does not in general satisfy the monotonicity requirement as a measure of coherence under the subselection of measurements condition. We find that the trace norm of coherence can act as a measure of coherence for qubit case and some special class of qutrits.

  18. Coherent Quantum Dynamics: What Fluctuations Can Tell

    E-Print Network [OSTI]

    Schliemann, John

    2015-01-01T23:59:59.000Z

    Coherent states provide a natural connection of quantum systems to their classical limit and are employed in various fields of physics. Here we derive general systematic expansions, with respect to quantum parameters, of expectation values of products of arbitrary operators within both oscillator coherent states and SU(2) coherent states. In particular, we generally prove that the energy fluctuations of an arbitrary Hamiltonian are in leading order entirely due to the time dependence of the classical variables. These results add to the list of wellknown properties of coherent states and are applied here to the Lipkin-Meshkov-Glick model, the Dicke model, and to coherent intertwiners in spin networks as considered in Loop Quantum Gravity.

  19. Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy

    E-Print Network [OSTI]

    Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy material in the infrared and far-infrared region.1 It plays a vital role in being used as infrared windows the frequency-dependent optical properties and complex di- electric response of ZnS over a broad far-infrared

  20. Electromagnetic absorption mechanisms in metal nanospheres: Bulk and surface effects in radiofrequency-terahertz heating of nanoparticles

    E-Print Network [OSTI]

    Hanson, George

    in radiofrequency-terahertz heating of nanoparticles G. W. Hanson,1,a) R. C. Monreal,2 and S. P. Apell3 1 Department on the absorption of electromagnetic radiation by metallic nanoparticles in the radio and far infrared frequency by which nonmagnetic metallic nanoparticles can absorb low frequency radiation, including both classical

  1. Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky*

    E-Print Network [OSTI]

    Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors Jiangquan time-domain spectroscopy (THz-TDS) study of hydrophobic and hydrophilic silica aerogels, and the adsorption of several molecular vapors in the hydrophilic silica aerogel. The hydrophobic and hydrophilic

  2. Numerical and experimental study of a high-power narrow-line phase-locked tapered lasers array in external cavity

    E-Print Network [OSTI]

    Boyer, Edmond

    of their beams by phase locking between the emitters. This has already been investigated successfully with CO2 benefit of the self-imaging Talbot properties inside an external cavity to induce the coherent emission describes the self-imaging properties of a periodic coherent field [3]. It is a pure Fresnel diffractive

  3. Design and 3D simulation of a two-cavity wide-gap relativistic klystron amplifier with high power injection

    SciTech Connect (OSTI)

    Bai Xianchen; Yang Jianhua; Zhang Jiande [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2012-08-15T23:59:59.000Z

    By using an electromagnetic particle-in-cell (PIC) code, an S-band two-cavity wide-gap klystron amplifier (WKA) loaded with washers/rods structure is designed and investigated for high power injection application. Influences of the washers/rods structure on the high frequency characteristics and the basic operation of the amplifier are presented. Generally, the rod structure has great impacts on the space-charge potential depression and the resonant frequency of the cavities. Nevertheless, if only the resonant frequency is tuned to the desired operation frequency, effects of the rod size on the basic operation of the amplifier are expected to be very weak. The 3-dimension (3-D) PIC simulation results show an output power of 0.98 GW corresponding to an efficiency of 33% for the WKA, with a 594 keV, 5 kA electron beam guided by an external magnetic field of 1.5 Tesla. Moreover, if a conductive plane is placed near the output gap, such as the electron collector, the beam potential energy can be further released, and the RF power can be increased to about 1.07 GW with the conversion efficiency of about 36%.

  4. Experimental investigation of factors limiting slow axis beam quality in 9xx nm high power broad area diode lasers

    SciTech Connect (OSTI)

    Winterfeldt, M., E-mail: martin.winterfeldt@fbh-berlin.de; Crump, P.; Wenzel, H.; Erbert, G.; Tränkle, G. [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany)

    2014-08-14T23:59:59.000Z

    GaAs-based broad-area diode lasers are needed with improved lateral beam parameter product (BPP{sub lat}) at high power. An experimental study of the factors limiting BPP{sub lat} is therefore presented, using extreme double-asymmetric (EDAS) vertical structures emitting at 910?nm. Continuous wave, pulsed and polarization-resolved measurements are presented and compared to thermal simulation. The importance of thermal and packaging-induced effects is determined by comparing junction -up and -down devices. Process factors are clarified by comparing diodes with and without index-guiding trenches. We show that in all cases studied, BPP{sub lat} is limited by a non-thermal BPP ground-level and a thermal BPP, which depends linearly on self-heating. Measurements as a function of pulse width confirm that self-heating rather than bias-level dominates. Diodes without trenches show low BPP ground-level, and a thermal BPP which depends strongly on mounting, due to changes in the temperature profile. The additional lateral guiding in diodes with trenches strongly increases the BPP ground-level, but optically isolates the stripe from the device edges, suppressing the influence of the thermal profile, leading to a BPP-slope that is low and independent of mounting. Trenches are also shown to initiate strain fields that cause parasitic TM-polarized emission with large BPP{sub lat}, whose influence on total BPP{sub lat} remains small, provided the overall polarization purity is >95%.

  5. Characterization of the Li(Si)/CoS(2) couple for a high-voltage, high-power thermal battery

    SciTech Connect (OSTI)

    GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.

    2000-02-01T23:59:59.000Z

    In order to determined the capabilities of a thermal battery with high-voltage and high-power requirements, a detailed characterization of the candidate LiSi/LiCl-LiBr-LiF/CoS{sub 2} electrochemical couple was conducted. The rate capability of this system was investigated using 0.75 inch-dia. and 1.25 inch-dia. single and multiple cells under isothermal conditions, where the cells were regularly pulsed at increasingly higher currents. Limitations of the electronic loads and power supplies necessitated using batteries to obtain the desired maximum current densities possible for this system. Both 1.25 inch-dia. and 3 inch-dia. stacks were used with the number of cells ranging from 5 to 20. Initial tests involved 1.25 inch-dia. cells, where current densities in excess of 15 A/cm{sup 2} (>200 W/cm{sup 2}) were attained with 20-cell batteries during 1-s pulses. In subsequent follow-up tests with 3 inch-dia., 10-cell batteries, ten 400-A 1-s pulses were delivered over an operating period often minutes. These tests formed the foundation for subsequent full-sized battery tests with 125 cells with this chemistry.

  6. Spatial distribution of average charge state and deposition rate in high power impulse magnetron sputtering of copper

    SciTech Connect (OSTI)

    Anders, Andre; Horwat, David; Anders, Andre

    2008-05-10T23:59:59.000Z

    The spatial distribution of copper ions and atoms in high power impulse magnetron sputtering (HIPIMS) discharges was determined by (i) measuring the ion current to electrostatic probes and (ii) measuring the film thickness by profilometry. A set of electrostatic and collection probes were placed at different angular positions and distances from the target surface. The angular distribution of the deposition rate and the average charge state of the copper species (including ions and neutrals) were deduced.The discharge showed a distinct transition to a high current mode dominated by copper self-sputtering when the applied voltage exceeded the threshold of 535 V. For a lower voltage, the deposition rate was very low and the average charge state was found to be less than 0.4. For higher voltage (and average power), the absolute deposition rates were much higher, but they were smaller than the corresponding direct current (DC) rates if normalized to the same average power. At the high voltage level, the spatial distribution of the average charge state showed some similarities with the distribution of the magnetic field, suggesting that the generation and motion of copper ions is affected by magnetized electrons. At higher voltage, the average charge state increases with the distance from the target and locally may exceed unity, indicating the presence of significant amounts of doubly charged copper ions.

  7. Optimization of Acetylene Black Conductive Additive andPolyvinylidene Difluoride Composition for High Power RechargeableLithium-Ion Cells

    SciTech Connect (OSTI)

    Liu, G.; Zheng, H.; Battaglia, V.S.; Simens, A.S.; Minor, A.M.; Song, X.

    2007-07-01T23:59:59.000Z

    Fundamental electrochemical methods were applied to study the effect of the acetylene black (AB) and the polyvinylidene difluoride (PVDF) polymer binder on the performance of high-power designed rechargeable lithium ion cells. A systematic study of the AB/PVDF long-range electronic conductivity at different weight ratios is performed using four-probe direct current tests and the results reported. There is a wide range of AB/PVDF ratios that satisfy the long-range electronic conductivity requirement of the lithium-ion cathode electrode; however, a significant cell power performance improvement is observed at small AB/PVDF composition ratios that are far from the long-range conductivity optimum of 1 to 1.25. Electrochemical impedance spectroscopy (EIS) tests indicate that the interfacial impedance decreases significantly with increase in binder content. The hybrid power pulse characterization results agree with the EIS tests and also show improvement for cells with a high PVDF content. The AB to PVDF composition plays a significant role in the interfacial resistance. We believe the higher binder contents lead to a more cohesive conductive carbon particle network that results in better overall all local electronic conductivity on the active material surface and hence reduced charge transfer impedance.

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

    SciTech Connect (OSTI)

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

    2006-01-01T23:59:59.000Z

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

  9. Origin of the energetic ion beams at the substrate generated during high power pulsed magnetron sputtering of titanium

    E-Print Network [OSTI]

    Maszl, Christian; Benedikt, Jan; von Keudell, Achim

    2013-01-01T23:59:59.000Z

    High power pulsed magnetron sputtering (HiPIMS) plasmas generate energetic metal ions at the substrate as a major difference to conventional direct current magnetron sputtering. The origin of these energetic ions in HiPIMS is still an open issue, which is unraveled by using three fast diagnostics: time resolved mass spectrometry with a temporal resolution of 2 $\\mu$s, phase resolved optical emission spectroscopy with 1 $\\mu$s and the rotating shutter experiment with a resolution of 50 $\\mu$s. A power scan from dcMS-like to HiPIMS plasmas was performed, with a 2-inch magnetron and a titanium target as sputter source and argon as working gas. Clear differences in the transport as well in the energetic properties of Ar$^+$, Ar$^{2+}$, Ti$^+$ and Ti$^{2+}$ were observed. For discharges with highest peak power densities a high energetic group of Ti$^{+}$ and Ti$^{2+}$ could be identified. A cold group of ions is always present. It is found that hot ions are observed only, when the plasma enters the spokes regime, ...

  10. Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields (invited)

    SciTech Connect (OSTI)

    Klepper, C. C., E-mail: kleppercc@ornl.gov; Isler, R. C.; Biewer, T. M.; Caughman, J. B.; Green, D. L.; Harris, J. H.; Hillis, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); Martin, E. H. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); North Carolina State University, Raleigh, North Carolina 27607 (United States); Colas, L.; Goniche, M.; Hillairet, J.; Panayotis, S.; Pegourié, B.; Jacquot, J.; Lotte, Ph.; Colledani, G.; Ekedahl, A.; Litaudon, X. [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Shannon, S. C. [North Carolina State University, Raleigh, North Carolina 27607 (United States)

    2014-11-15T23:59:59.000Z

    An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (>?1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

  11. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOE Patents [OSTI]

    Veligdan, J.T.

    1994-03-08T23:59:59.000Z

    An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90[degree] angle of incidence. 8 figures.

  12. Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields

    SciTech Connect (OSTI)

    Klepper, C Christopher [ORNL; Martin, Elijah H [ORNL; Isler, Ralph C [ORNL; Colas, L. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Goniche, M. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Hillairet, J. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Panayotis, Stephanie [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Jacquot, Jonathan [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Lotte, Ph. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Colledani, G. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Biewer, Theodore M [ORNL; Caughman, J. B. O. [Oak Ridge National Laboratory (ORNL); Ekedahl, A. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Green, David L [ORNL; Harris, Jeffrey H [ORNL; Hillis, Donald Lee [ORNL; Shannon, Prof. Steven [North Carolina State University; Litaudon, X [French Atomic Energy Commission (CEA)

    2014-01-01T23:59:59.000Z

    An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (> 1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

  13. Polarity dependence of the electrical characteristics of Ag reflectors for high-power GaN-based light emitting diodes

    SciTech Connect (OSTI)

    Park, Jae-Seong; Seong, Tae-Yeon, E-mail: tyseong@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Han, Jaecheon [Department of LED Business, Chip Development Group, LG Innotek, Paju 413-901 (Korea, Republic of); Ha, Jun-Seok [School of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

    2014-04-28T23:59:59.000Z

    We report on the polarity dependence of the electrical properties of Ag reflectors for high-power GaN-based light-emitting diodes. The (0001) c-plane samples become ohmic after annealing in air. However, the (11–22) semi-polar samples are non-ohmic after annealing, although the 300?°C-annealed sample shows the lowest contact resistivity. The X-ray photoemission spectroscopy (XPS) results show that the Ga 2p core level for the c-plane samples experiences larger shift toward the valence band than that for the semi-polar samples. The XPS depth profile results show that unlike the c-plane samples, the semi-polar samples contain some amounts of oxygen at the Ag/GaN interface regions. The outdiffusion of Ga atoms is far more significant in the c-plane samples than in the semi-polar samples, whereas the outdiffusion of N atoms is relatively less significant in the c-plane samples. On the basis of the electrical and XPS results, the polarity dependence of the electrical properties is described and discussed.

  14. aligning coherent bremsstrahlung: Topics by E-print Network

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

    internal state of the plant. Importantly, coherent observers avoid measurements of the plant outputs. We compare our coherent observers with a classical (measurement-based)...

  15. Terahertz surface plasmon waveguide based on a one-dimensional array of silicon pillars This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Murphy, Thomas E.

    -wavelength pillars on a silicon substrate. Doped silicon can exhibit conductive properties at terahertz frequencies wires [14], parallel plate transmission lines [15], hollow polycarbonate waveguides [16] and corrugated

  16. High-power, hybrid Er:fiber/Tm:fiber frequency comb source in the 2 {\\mu}m wavelength region

    E-Print Network [OSTI]

    Adler, Florian

    2012-01-01T23:59:59.000Z

    We present a 2-\\mum frequency comb based on a reliable mode-locked Er:fiber laser with 100 MHz repetition rate. After shifting the spectrum of the amplified Er:fiber comb to longer wavelengths, a single-clad Tm/Ho:fiber is used as a self-pumped pre-amplifier to generate a coherent and broadband spectrum centered at 1.93 \\mum. Subsequently, a cladding-pumped Tm:fiber amplifier boosts the system to a maximum output power of 4.8 W at 1.96 \\mum. After compression in a compact grating compressor, our amplified Er:fiber/Tm:fiber hybrid system delivers as much as 2.9 W with a pulse duration of 141 fs. The system's comb properties are examined via heterodyne measurement.

  17. Conference 5739, SPIE International Symposium Integrated Optoelectronic Devices, 22-27 Jan 2005, San Jose, CA Development of high power green light emitting diode dies in

    E-Print Network [OSTI]

    Wetzel, Christian M.

    , San Jose, CA Development of high power green light emitting diode dies in piezoelectric Ga in green light emitting diodes is one of the big challenges towards all-solid- state lighting. The prime,3], and commercialization [4,5] of high brightness light emitting diodes LEDs has led to a 1.82 Billion-$/year world market

  18. Journal of Power Sources 153 (2006) 6875 Numerical study of a flat-tube high power density solid oxide fuel cell

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    power density (HPD) solid oxide fuel cell (SOFC) is a geometry based on a tubular type SOFC: Flat-tube; High power density (HPD); Solid oxide fuel cell (SOFC); Simulation; Performance; Optimization 1. Introduction A solid oxide fuel cell (SOFC), like any other fuel cell, produces electrical

  19. Journal of Power Sources 140 (2005) 331339 Numerical study of a flat-tube high power density solid oxide fuel cell

    E-Print Network [OSTI]

    2005-01-01T23:59:59.000Z

    ) solid oxide fuel cell (SOFC) is a new design developed by Siemens Westinghouse, based on their formerly.V. All rights reserved. Keywords: Flat-tube; High power density; Solid oxide fuel cell; Simulation; Heat oxide fuel cell Part I. Heat/mass transfer and fluid flow Yixin Lu1, Laura Schaefer, Peiwen Li2

  20. A Model for Tunneling-Limited Breakdown in High-Power HEMTs Mark H. Somerville and Jes6s A. del Alamo

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    A Model for Tunneling-Limited Breakdown in High-Power HEMTs Mark H. Somerville and Jes6s A. del indicates that the cru- cial variables in determining the off-state breakdown volt- age of power HEMTs. Other design parameters have only secondary impact on the breakdown voltage for realistic device designs

  1. Micro capillary pumped loop system for a cooling high power device Chin-Tsan Wang a,*, Tzong-Shyng Leu b

    E-Print Network [OSTI]

    Leu, Tzong-Shyng "Jeremy"

    Micro capillary pumped loop system for a cooling high power device Chin-Tsan Wang a,*, Tzong-driven two-phase loop, configured on a micro capillary pumped loop (MCPL) system without an external power. The combination of micro-scale heat transfer and fluid dynamics along with high surface-to-volume ratios makes

  2. Nuclear Instruments and Methods in Physics Research A 528 (2004) 1518 First lasing at the high-power free electron laser at Siberian

    E-Print Network [OSTI]

    Kozak, Victor R.

    2004-01-01T23:59:59.000Z

    -power free electron laser at Siberian center for photochemistry research E.A. Antokhin, R.R. Akberdin, V in April 2003 on a high-power free electron laser (FEL) constructed at the Siberian Center. 2. Accelerator­recuperator Full-scale Novosibirsk free electron laser is to be based on multi

  3. Temperature-Accelerated Degradation of GaN HEMTs under High-Power Stress: Activation Energy of Drain-Current Degradation

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    that allows device characterization through external test equipment [1]. A flow chart of a typical stepTemperature-Accelerated Degradation of GaN HEMTs under High- Power Stress: Activation Energy on this observation, we demonstrate a new scheme to extract the activation energy (Ea) of device degradation from step

  4. Spatial distribution of structural degradation under high-power stress in AlGaN/GaN high electron mobility transistors

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    and high temperature, the latter being a result of de- vice self-heating. A complicating factor degradation of AlGaN/GaN high electron mobility transistors was investigated under high-power electrical electrical degradation that was mostly driven by an electric field across the AlGaN barrier. Under high

  5. High Power GaN Oscillators using Field-Plated HEMT Structure Hongtao Xu, Christopher Sanabria, Sten Heikman, Stacia Keller, Umesh K. Mishra, and Robert A.

    E-Print Network [OSTI]

    York, Robert A.

    High Power GaN Oscillators using Field-Plated HEMT Structure Hongtao Xu, Christopher Sanabria, Sten Engineering University of California, Santa Barbara, California 93106, USA Abstract -- 5 GHz MMIC GaN oscillators based on AlGaN/GaN HEMTs are presented. By using field-plated HEMT structures, both the output

  6. Impact of high-power stress on dynamic ON-resistance of high-voltage GaN HEMTs Donghyun Jin

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    Impact of high-power stress on dynamic ON-resistance of high-voltage GaN HEMTs Donghyun Jin-resistance (RON) in high- voltage GaN High-Electron-Mobility Transistors (HEMTs). We use a newly proposed dynamic. All rights reserved. 1. Introduction In the last decade, GaN Field-Effect Transistors have emerged

  7. Quantum Coherence Arguments for Cosmological Scale

    SciTech Connect (OSTI)

    Lindesay, James; /SLAC

    2005-05-27T23:59:59.000Z

    Homogeneity and correlations in the observed CMB are indicative of some form of cosmological coherence in early times. Quantum coherence in the early universe would be expected to give space-like phase coherence to any effects sourced to those times. If dark energy de-coherence is assumed to occur when the rate of expansion of the relevant cosmological scale parameter in the Friedmann-Lemaitre equations is no longer supra-luminal, a critical energy density is immediately defined. It is shown that the general class of dynamical models so defined necessarily requires a spatially flat cosmology in order to be consistent with observed structure formation. The basic assumption is that the dark energy density which is fixed during de-coherence is to be identified with the cosmological constant. It is shown for the entire class of models that the expected amplitude of fluctuations driven by the dark energy de-coherence process is of the order needed to evolve into the fluctuations observed in cosmic microwave background radiation and galactic clustering. The densities involved during de-coherence which correspond to the measured dark energy density turn out to be of the electroweak symmetry restoration scale. In an inflationary cosmology, this choice of the scale parameter in the FL equations directly relates the scale of dark energy decoherence to the De Sitter scales (associated with the positive cosmological constants) at both early and late times.

  8. Use of High-Power Brayton Nuclear Electric Propulsion (NEP) for a 2033 Mars Round-Trip Mission

    SciTech Connect (OSTI)

    McGuire, Melissa L. [Space Propulsion and Mission Analysis Office (Code: PBM), NASA Glenn Research Center, MS 500-103, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Martini, Michael C.; Packard, Thomas W. [Space Propulsion and Mission Analysis Office (Code: PBM), NASA Glenn Research Center, MS 500-103, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Analex Corporation, 1100 Apollo Drive, Brook Park, OH 44142 (United States); Weglian, John E. [Space Propulsion and Mission Analysis Office (Code: PBM), NASA Glenn Research Center, MS 500-103, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Ohio Aerospace Institute, 22800 Cedar Point Rd., Brook Park, OH 44142 (United States); Gilland, James H. [Ohio Aerospace Institute, 22800 Cedar Point Rd., Brook Park, OH 44142 (United States)

    2006-01-20T23:59:59.000Z

    The Revolutionary Aerospace Systems Concepts (RASC) team, led by the NASA Langley Research Center, is tasked with exploring revolutionary new approaches to enabling NASA to achieve its strategic goals and objectives in future missions. This paper provides the details from the 2004-2005 RASC study of a point-design that uses a high-power nuclear electric propulsion (NEP) based space transportation architecture to support a manned mission to Mars. The study assumes a high-temperature liquid-metal cooled fission reactor with a Brayton power conversion system to generate the electrical power required by magnetoplasmadynamic (MPD) thrusters. The architecture includes a cargo vehicle with an NEP system providing 5 MW of electrical power and a crewed vehicle with an NEP system with two reactors providing a combined total of 10 MW of electrical power. Both vehicles use a low-thrust, high-efficiency (5000 sec specific impulse) MPD system to conduct a spiral-out of the Earth gravity well, a low-thrust heliocentric trajectory, and a spiral-in at Mars with arrival late in 2033. The cargo vehicle carries two moon landers to Mars and arrives shortly before the crewed vehicle. The crewed vehicle and cargo vehicle rendezvous in Mars orbit and, over the course of the 60-day stay, the crew conducts nine-day excursions to Phobos and Deimos with the landers. The crewed vehicle then spirals out of Martian orbit and returns via a low-thrust trajectory to conduct an Earth flyby. The crew separates from the vehicle prior to Earth flyby and aerobrakes for a direct-entry landing.

  9. Lorentz Coherence and the Proton Form Factor

    E-Print Network [OSTI]

    Kim, Young S

    2015-01-01T23:59:59.000Z

    The dipole cutoff behavior for the proton form factor has been and still is one of the major issues in high-energy physics. It is shown that this dipole behavior comes from the coherence between the Lorentz contraction of the proton size and the decreasing wavelength of the incoming photon signal. The contraction rates are the same for both cases. This form of coherence is studied also in the momentum-energy space. The coherence effect in this space can be explained in terms of two overlapping wave functions.

  10. Lorentz Coherence and the Proton Form Factor

    E-Print Network [OSTI]

    Young S. Kim

    2015-02-28T23:59:59.000Z

    The dipole cutoff behavior for the proton form factor has been and still is one of the major issues in high-energy physics. It is shown that this dipole behavior comes from the coherence between the Lorentz contraction of the proton size and the decreasing wavelength of the incoming photon signal. The contraction rates are the same for both cases. This form of coherence is studied also in the momentum-energy space. The coherence effect in this space can be explained in terms of two overlapping wave functions.

  11. Power and capacity fade mechanism of LiNi0.8Co0.15Al0.0502 composite cathodes in high-power lithium-ion batteries

    E-Print Network [OSTI]

    Kostecki, Robert; McLarnon, Frank

    2003-01-01T23:59:59.000Z

    LIFE REDUCTION IN HIGH-POWER LITHIUM-ION BATTERIES RobertRaman, AFM Introduction Lithium-ion batteries are being

  12. Asymmetric Cache Coherency: Policy Modifications to Improve Multicore Performance

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    coherency policy, generated a 60% coherency cost reduction (reduction of latencies due to coherency messages-Sud Guy Gogniat, Lab-STICC, Universit´e de Bretagne-Sud Asymmetric coherency is a new optimisation method page or initial screen of a display along with the full citation. Copyrights for components

  13. CALIBRATION, COHERENCE, AND SCORING RULES* TEDDY SEIDENFELDt

    E-Print Network [OSTI]

    Fitelson, Branden

    CALIBRATION, COHERENCE, AND SCORING RULES* TEDDY SEIDENFELDt Department of Philosophy Washington, I focus on one such aspirant: calibration. Cal- ibration requires an alignment of announced: (i) Surveys designed to display calibration curves, from which a recalibration is to be calculated

  14. Coherent regulation in yeast cell cycle network

    E-Print Network [OSTI]

    Nese Aral; Alkan Kabakcioglu

    2014-12-14T23:59:59.000Z

    We define a measure of coherent activity for gene regulatory networks, a property that reflects the unity of purpose between the regulatory agents with a common target. We propose that such harmonious regulatory action is desirable under a demand for energy efficiency and may be selected for under evolutionary pressures. We consider two recent models of the cell-cycle regulatory network of the budding yeast, Saccharomyces cerevisiae, as a case study and calculate their degree of coherence. A comparison with random networks of similar size and composition reveals that the yeast's cell-cycle regulation is wired to yield and exceptionally high level of coherent regulatory activity. We also investigate the mean degree of coherence as a function of the network size, connectivity and the fraction of repressory/activatory interactions.

  15. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    E-Print Network [OSTI]

    Hockett, Paul; Baumert, Thomas

    2015-01-01T23:59:59.000Z

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  16. Coherence properties of the radiation from FLASH

    E-Print Network [OSTI]

    Schneidmiller, E A

    2015-01-01T23:59:59.000Z

    FLASH is the first free electron laser user facility operating in the vacuum ultraviolet and soft x-ray wavelength range. Many user experiments require knowledge of the spatial and temporal coherence properties of the radiation. In this paper we present an analysis of the coherence properties of the radiation for the fundamental and for the higher odd frequency harmonics. We show that temporal and spatial coherence reach maximum close to the FEL saturation but may degrade significantly in the post-saturation regime. We also find that the pointing stability of short FEL pulses is limited due to the fact that non-azimuthal FEL eigenmodes are not sufficiently suppressed. We discuss possible ways for improving the degree of transverse coherence and the pointing stability.

  17. The extraction of work from quantum coherence

    E-Print Network [OSTI]

    Kamil Korzekwa; Matteo Lostaglio; Jonathan Oppenheim; David Jennings

    2015-06-25T23:59:59.000Z

    We critically assess the problem of extracting work from a coherent superposition of energy eigenstates of an individual qubit system. By carefully taking into account all the resources involved in the thermodynamic transformations in a fully quantum-mechanical treatment, we show that there exists a thermal machine that can come arbitrarily close to extracting all the coherence as work. The machine only needs to act on individual copies of a state and can be reused. On the other hand, we show that for any thermal machine with finite resources not all the coherence of a state can be extracted as work. We provide explicit protocols extracting work from coherence when the resources of a thermal machine are bounded, a scenario potentially relevant for the thermodynamics at the nanoscale.

  18. Coherent neutrino scattering in dark matter detectors

    E-Print Network [OSTI]

    Anderson, Alexander John

    Coherent elastic neutrino-nucleus and weakly interacting massive particle-nucleus interaction signatures are expected to be quite similar. This paper discusses how a next-generation ton-scale dark matter detector could ...

  19. Managing coherence via put/get windows

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

    2011-01-11T23:59:59.000Z

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

  20. Managing coherence via put/get windows

    DOE Patents [OSTI]

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Ohmacht, Martin (Yorktown Heights, NY)

    2012-02-21T23:59:59.000Z

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.