National Library of Energy BETA

Sample records for term pulse mode

  1. Single mode pulsed dye laser oscillator

    DOE Patents [OSTI]

    Hackel, Richard P. (Livermore, CA)

    1992-01-01

    A single mode pulsed dye laser oscillator is disclosed. The dye laser oscillator provides for improved power efficiency by reducing the physical dimensions of the overall laser cavity, which improves frequency selection capability.

  2. Pulse-mode temperature sensing with langasite SAW devices

    E-Print Network [OSTI]

    Greve, David.W.

    combustion process. Their temperature responses were measured in pulse mode both wired to a highPulse-mode temperature sensing with langasite SAW devices Peng Zheng*1,2 , T.-L. Chin1,3 , David W is increasingly important for many industrial processes, such as control of oxy-fuel combustion

  3. Improvement in the statistical operation of a Blumlein pulse forming line in bipolar pulse mode

    SciTech Connect (OSTI)

    Pushkarev, A. I., E-mail: aipush@mail.ru; Isakova, Y. I.; Khaylov, I. P. [Laboratory of Beam and Plasma Technologies, Tomsk Polytechnic University, 2a Lenin Ave., Tomsk 634028 (Russian Federation)

    2014-07-15

    The paper presents the results of studies on shot-to-shot performance of a water Blumlein pulse forming line of 1–1.2 kJ of stored energy. The experiments were carried using the TEMP-4M pulsed ion beam accelerator during its operation in both unipolar pulse mode (150 ns, 250–300 kV) and bipolar-pulse mode with the first negative (300–600 ns, 100–150 kV) followed by a second positive (120 ns, 250–300 kV) pulse. The analysis was carried out for two cases when the Blumlein was terminated with a resistive load and with a self-magnetically insulated ion diode. It was found that in bipolar pulse mode the shot-to-shot variation in breakdown voltage of a preliminary spark gap is small, the standard deviation (1?) does not exceed 2%. At the same time, the shot-to-shot variation in the breakdown voltage of the main spark gap in both bipolar-pulse and unipolar pulse mode is 3–4 times higher than that for the preliminary spark gap. To improve the statistical performance of the main spark gap we changed the regime of its operation from a self-triggered mode to an externally triggered mode. In the new arrangement the first voltage pulse at the output of Blumlein was used to trigger the main spark gap. The new trigatron-type regime of the main spark gap operation showed a good stability of breakdown voltage and thus allowed to stabilize the duration of the first pulse. The standard deviation of the breakdown voltage and duration of the first pulse did not exceed 2% for a set of 50 pulses. The externally triggered mode of the main gap operation also allowed for a decrease in the charging voltage of the Blumlein to a 0.9–0.95 of self-breakdown voltage of the main spark gap while the energy stored in Marx generator was decreased from 4 kJ to 2.5 kJ. At the same time the energy stored in Blumlein remained the same.

  4. Limits of ultrashort pulse generation in cw mode-locked dye lasers

    SciTech Connect (OSTI)

    Petrov, V.; Rudolph, W.; Stamm, U.; Wilhelmi, B.

    1989-08-01

    Essential mechanisms limiting the achievable pulse duration in synchronously pumped, hybrid-mode-locked, and passively mode-locked cw subpicosecond dye lasers are analyzed. The action of spontaneously emitted light is shown to be the detrimental factor in synchronous mode locking. The influence of this factor can be suppressed by a saturable absorber in the hybrid-mode-locked lasers. In this case as well as in the case of passive mode locking the combined action of group-velocity dispersion and Kerr-effect-type nonlinearity, though serving as an additional shortening mechanism, causes fluctuations of the pulse parameters and determines the limit of the steady-state regime.

  5. Ultra-low repetition rate mode-locked fiber laser with high-energy pulses

    E-Print Network [OSTI]

    Kobtsev, Sergei M.

    of research into passively mode- locked fiber laser with a record-setting optical length of the resonant-repetition rate high- energy picosecond pulses from a single-wall carbon nanotube mode-locked fiber laser," presented at the Optical Amplifiers and their Applications Conference (OAA 2006), Whistler, British Columbia

  6. Improved performance in long-pulse ELMy H-mode plasmas

    E-Print Network [OSTI]

    and fast ion losses Improvement of ELMy H-mode performance ­ Extension of sustained time duration of high NImproved performance in long-pulse ELMy H-mode plasmas with internal transport barrier in JT-60U N with large non- inductive current should be sustained longer than R. Sustainability of ITB, which drives

  7. Flat-top pulse generation based on the combined action of active mode locking and nonlinear polarization rotation

    E-Print Network [OSTI]

    Wai, Ping-kong Alexander

    Flat-top pulse generation based on the combined action of active mode locking and nonlinear: A pulsewidth tunable 10 GHz flat-top pulse train is generated based on the combined action of active mode locking and nonlinear-polarization-rotation pulse shaping. The SMSR is 65 dB and the timing jitter is 145

  8. Few-cycle pulses from a graphene mode-locked all-fiber laser

    E-Print Network [OSTI]

    Purdie, D; Wittwer, V J; Jiang, Z; Bonacchini, G; Torrisi, F; Milana, S; Lidorikis, E; Ferrari, A C

    2015-01-01

    We combine a graphene mode-locked oscillator with an external compressor and achieve~29fs pulses with~52mW average power. This is a simple, low-cost, and robust setup, entirely fiber based, with no free-space optics, for applications requiring high temporal resolution.

  9. Design and optimization of 6li neutron-capture pulse mode ion chamber 

    E-Print Network [OSTI]

    Chung, Kiwhan

    2009-05-15

    The purpose of this research is to design and optimize the performance of a unique, inexpensive 6Li neutron-capture pulse-mode ion chamber (LiPMIC) for neutron detection that overcomes the fill-gas contamination stemming from outgas of detector...

  10. Statistical mechanical theory of mode-locked multimode lasers in closed cavity: determination of thresholds, spectra, pulse phase delays and pulse correlations

    E-Print Network [OSTI]

    Antenucci, Fabrizio; Leuzzi, Luca

    2014-01-01

    A study of the Mode-locking lasing pulse formation in closed cavities is presented within a statistical mechanical framework where the onset of laser coincides with a thermodynamic phase transition driven by the optical power pumped into the system. Electromagnetic modes are represented by classical degrees of freedom of a Hamiltonian model at equilibrium in an effective ensemble corresponding to the stationary laser regime. By means of optimized Monte Carlo numerical simulations, the system properties are analyzed varying mode interaction dilution, gain profile and number of modes. Novel properties of the resulting mode-locking laser phase are presented, not observable by previous mean-field approaches. For strong dilution of the nonlinear interaction network, power condensation occurs as the whole optical intensity is taken by a few electromagnetic modes, whose number does not depend on the size of the system. For all reported cases laser thresholds, intensity spectra, and ultra-fast electromagnetic pulses ...

  11. Influence of transient absorber gratings on the pulse parameters of passively mode-locked cw dye ring lasers

    SciTech Connect (OSTI)

    Kuehlke, D.; Rudolph, W.; Wilhelmi, B.

    1983-02-15

    A theoretical explanation of the experimental results obtained by the method of colliding pulse mode locking (CPM) is given. It is shown that, compared to other passive methods, the coherent interaction of the counter-running pulses in the thin absorber yields considerably shorter pulses with a more favorable stability region. Deviations from an amplifier position being symmetric with respect to the amplification of the counter-running pulses lead to different energies of the pulses and to a strong decrease of the stability range of the CPM.

  12. Doubly-Resonant Fabry-Perot Cavity for Power Enhancement of Burst-Mode Picosecond Ultraviolet Pulses

    SciTech Connect (OSTI)

    Abudureyimu, Reheman [ORNL; Huang, Chunning [ORNL; Liu, Yun [ORNL

    2015-01-01

    We report on a first experimental demonstration of locking a doubly-resonant Fabry-Perot cavity to burst-mode picosecond ultraviolet (UV) pulses by using a temperature controlled dispersion compensation method. This technique will eventually enable the intra cavity power enhancement of burst-mode 402.5MHz/50ps UV laser pulses with a MW level peak power required for the laser assisted H- beam stripping experiment at the Spallation Neutron Source.

  13. Electromagnetic vacuum energy for two parallel slabs in terms of surface, wave guide and photonic modes

    E-Print Network [OSTI]

    M. Bordag

    2012-01-05

    The formulation of the Lifshitz formula in terms of real frequencies is reconsidered for half spaces described by the plasma model. It is shown that besides the surface modes (for the TM polarization), and the photonic modes, also waveguide modes must be considered.

  14. A molecular explanation for the long-term suppression of circadian rhythms by a single light pulse

    E-Print Network [OSTI]

    Goldbeter, Albert

    A molecular explanation for the long-term suppression of circadian rhythms by a single light pulse explanation for the long-term suppression of circadian rhythms by a single light pulse. Am J Physiol rhythms in Drosophila based on transcriptional regulation, we show how a single, critical pulse of light

  15. Pulsed single-mode laser ionization of hyperfine levels of zirconium-91

    SciTech Connect (OSTI)

    Hackett, P.A.; Morrison, H.D.; Bourne, O.L.; Simard, B.; Rayner, D.M.

    1988-12-01

    We identify a considerable improvement in proposed schemes for isotopic depletion of zirconium-91 on the basis of the atomic vapor laser isotope separation (AVLIS) method. The improvement lies in applying a single-longitudinal-mode dye laser for selective excitation of all hyperfine split levels of the ground state of zirconium-91. High-resolution laser-induced fluorescence spectroscopy of atomic beams of zirconium produced through laser vaporization--supersonic expansion has been used to identify transitions of zirconium with suitable hyperfine structure. Casimir magnetic-dipole and electric-quadrupole coupling constants and isotope shifts have been derived and are reported for five excited configurations. Suitable intermediate levels in a multistep resonance ionization pathway have been identified by two-color resonance ionization spectroscopy. Isotope depletion has been demonstrated on one ground state transition (z /sup 3/F/sup circle-open//sub 3/ left-arrowa /sup 3/F/sub 2/ at 593.7 nm) by using a specially constructed pulsed, single-longitudinal-mode dye-laser oscillator. Prospects and future directions in zirconium AVLIS are discussed.

  16. 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)

    2014-06-15

    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.

  17. Abnormal electron-heating mode and formation of secondary-energetic electrons in pulsed microwave-frequency atmospheric microplasmas

    SciTech Connect (OSTI)

    Kwon, H. C.; Research and Development Division, SK Hynix Semiconductor Inc., Icheon 467-701 ; Jung, S. Y.; Kim, H. Y.; Won, I. H.; Lee, J. K.

    2014-03-15

    The formation of secondary energetic electrons induced by an abnormal electron-heating mode in pulsed microwave-frequency atmospheric microplasmas was investigated using particle-in-cell simulation. We found that additional high electron heating only occurs during the first period of the ignition phase after the start of a second pulse at sub-millimeter dimensions. During this period, the electrons are unable to follow the abruptly retreating sheath through diffusion alone. Thus, a self-consistent electric field is induced to drive the electrons toward the electrode. These behaviors result in an abnormal electron-heating mode that produces high-energy electrons at the electrode with energies greater than 50?eV.

  18. NO{sub x} and CO emissions from a pulse combustor operating in a lean premixed mode

    SciTech Connect (OSTI)

    Keller, J.O.; Bramlette, T.T.; Barr, P.K.; Alvarez, J.

    1993-04-01

    Emission levels below 5.0 ppM NO{sub x}, with corresponding levels of 75 ppM CO (corrected to 3% O{sub 2}), were achieved in a pulse combustor operating in a lean premixed mode. Both NO{sub x} and CO concentrations were invariant with the total mass flow rate, but NO{sub x} and CO concentrations did vary with the rate of microscopic mixing.

  19. Generation of synchronized trains of picosecond laser pulses at two wavelengths in a single-cavity synchronously mode-locked dye laser

    E-Print Network [OSTI]

    Rocca, Jorge J.

    Generation of synchronized trains of picosecond laser pulses at two wavelengths in a single September 1992) Synchronized trains of 5 ps pulses at two wavelengths were generated in a single-cavity synchronously mode-locked dye laser 0. Buccafusca, J. J. Rocca, M. C. Marconi, and C. S. Menoni National Science

  20. Digital Sliding Mode Pulsed Current Averaging IC Drivers for High Brightness Light Emitting Diodes

    E-Print Network [OSTI]

    Lehman, Brad

    to the load. A variable frequency boost converter in Discontinuous Conduction Mode (DCM) has been used algorithm of the inductor current variations for a digitally controlled DC-DC boost converter operating in Continuous Conduction Mode. [10] describes a microcontroller based digital boost converter for a RGB

  1. Long-term pulse profile study of the Be/X-ray pulsar SAX J2103.5+4545

    E-Print Network [OSTI]

    A. Camero Arranz; C. A. Wilson; M. H. Finger; V. Reglero

    2007-03-03

    Aims. We present the first long-term pulse profile study of the X-ray pulsar SAX J2103.5+4545. Our main goal is to study the pulse shape correlation either with luminosity, time or energy. Methods. This Be/X-ray binary system was observed from 1999 to 2004 by RXTE PCA, and by INTEGRAL from 2002 to 2005, during the Performance and Verification (PV) phase and the Galactic Plane Scan survey (GPS). X-ray pulse profiles were obtained in different energy ranges. The long-term spectral variability of this source is studied. The long-term flux, frequency and spin-up rate histories are computed. A new set of orbital parameters are also determined. Results. The pulse shape is complex and highly variable either with time or luminosity. However, an energy dependence pattern was found. Single, double, triple or even quadruple peaks pulse profile structure was obtained. It was confirmed that SAX J2103.5+4545 becomes harder when the flux is higher. The new orbital solution obtained is: P_orb= 12.66528+-0.00051 days, e = 0.401+-0.018, w = 241.36+-2.18 and a_xsin i = 80.81+-0.67 lt-s.

  2. NO[sub x] and CO emissions from a pulse combustor operating in a lean premixed mode

    SciTech Connect (OSTI)

    Keller, J.O.; Bramlette, T.T.; Barr, P.K.; Alvarez, J.R. (Sandia National Labs., Livermore, CA (United States). Combustion Research Facility)

    1994-12-01

    Control over the combustion fluid dynamics was used to minimize the emission of NO[sub x] and CO. The combustion kinetics were controlled by operating the combustor premixed and were varied by modifying the equivalence ratio over the lean stability envelope. A wide dynamic range in fluid dynamic mixing characteristics was also investigated by modifying the degree of macroscopic mixing and microscopic mixing. The residence time at high temperature was controlled by modifying the frequency of the periodic reacting flow in a pulse combustor. It was found that controlling the flame temperature, chemical kinetics, and residence time at high temperature was best accomplished by controlling the equivalence ratio and the degree of macroscopic mixing rather than controlling the microscopic mixing over the dynamic range obtainable by the techniques used in this study. Emission levels below 5.0 ppm NO[sub x], with corresponding levels of 5.0 ppm CO (corrected to 3% O[sub 2]), were achieved in a pulse combustor operating in a lean premixed mode, without the use of any post combustion cleanup technologies. Both NO[sub 2] and CO emissions were invariant to changes in the power input.

  3. Maximum relative excitation of a specific vibrational mode via optimum laser-pulse duration 

    E-Print Network [OSTI]

    Zhou, Xiang; Lin, Zhibin; Jiang, Chenwei; Gao, Meng; Allen, Roland E.

    2010-01-01

    not be truncated. ?ii? The FWHM duration is exactly half the full duration 2?. ?iii? A plot reveals that it closely resembles a Gaussian. ?iv? The slope is zero at beginning and end. ?2? The initial conditions Qk?0?=Q? k?0?=0 are imposed on the normal... for the quantized Hamiltonian H? = ? k ?P? k2/2 + ?k2Q? k2/2? ? ?? ? E ? E ? ?? ? E/2 ?4? with Qk??Q? k and ?k?????? /?Q? k , when the term involving ??? /?Qk vanishes or is neglected ?e.g., in taking rapid oscil- lations of the electric field E?t? to average...

  4. "DIAGNOSTIC" PULSE FOR SINGLE-PARTICLE-LIKE BEAM POSITION MEASUREMENTS DURING ACCUMULATION/PRODUCTION MODE IN THE LOS ALAMOS PROTON STORAGE RING

    SciTech Connect (OSTI)

    Kolski, Jeffrey S. [Los Alamos National Laboratory; Baily, Scott A. [Los Alamos National Laboratory; Bjorklund, Eric A. [Los Alamos National Laboratory; Bolme, Gerald O. [Los Alamos National Laboratory; Hall, Michael J. [Los Alamos National Laboratory; Kwon, Sung I. [Los Alamos National Laboratory; Martinez, Martin P. [Los Alamos National Laboratory; Prokop, Mark S. [Los Alamos National Laboratory; Shelley, Fred E. Jr. [Los Alamos National Laboratory; Torrez, Phillip A. [Los Alamos National Laboratory

    2012-05-14

    Beam position monitors (BPMs) are the primary diagnostic in the Los Alamos Proton Storage Ring (PSR). When injecting one turn, the transversemotion is approximated as a single particle with initial betatron position and angle {rvec x}{sub 0} and {rvec x}'{sub 0}. With single-turn injection, we fit the betatron tune, closed orbit (CO), and injection offset ({rvec x}{sub 0} and {rvec x}'{sub 0} at the injection point) to the turn-by-turn beam position. In production mode, we accumulate multiple turns, the transverse phase space fills after 5 injections (horizontal and vertical fractional betatron tunes {approx}0.2) resulting in no coherent betatron motion, and only the CO may be measured. The injection offset, which determines the accumulated beam size and is very sensitive to steering upstream of the ring, is not measurable in production mode. We describe our approach and ongoing efforts to measure the injection offset during production mode by injecting a 'diagnostic' pulse {approx}50 {micro}s after the accumulated beam is extracted. We also study the effects of increasing the linac RF gate length to accommodate the diagnostic pulse on the production beam position, transverse size, and loss.

  5. LONG-TERM PERFORMANCE OF SOLID OXIDE STACKS WITH ELECTRODE-SUPPORTED CELLS OPERATING IN THE STEAM ELECTROLYSIS MODE

    SciTech Connect (OSTI)

    J. E. O'Brien; R. C. O'Brien; X. Zhang; G. Tao; B. J. Butler

    2011-11-01

    Performance characterization and durability testing have been completed on two five-cell high-temperature electrolysis stacks constructed with advanced cell and stack technologies. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. The per-cell active area is 100 cm2. The stack is internally manifolded with compliant mica-glass seals. Treated metallic interconnects with integral flow channels separate the cells. Stack compression is accomplished by means of a custom spring-loaded test fixture. Initial stack performance characterization was determined through a series of DC potential sweeps in both fuel cell and electrolysis modes of operation. Results of these sweeps indicated very good initial performance, with area-specific resistance values less than 0.5 ?.cm2. Long-term durability testing was performed with A test duration of 1000 hours. Overall performance degradation was less than 10% over the 1000-hour period. Final stack performance characterization was again determined by a series of DC potential sweeps at the same flow conditions as the initial sweeps in both electrolysis and fuel cell modes of operation. A final sweep in the fuel cell mode indicated a power density of 0.356 W/cm2, with average per-cell voltage of 0.71 V at a current of 50 A.

  6. Microsoft PowerPoint - Arseneau_EIA_ShortTermDriversofEnergyPrices.ppt [Compatibility Mode]

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on darkMicroorganisms toPalladium wavy nanowires withTERM ENERGY

  7. Nerve-pulse interactions

    SciTech Connect (OSTI)

    Scott, A.C.

    1982-01-01

    Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

  8. The Theta Laser A Low Noise Chirped Pulse Laser

    E-Print Network [OSTI]

    Van Stryland, Eric

    The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser · Develop a frequency swept laser, · linear f-sweep, · uniform-intensity, · low noise, · with long-term stability

  9. The Role of Lithium Conditioning in Achieving High Performance, Long Pulse H-mode Discharges in the NSTX and EAST Devices

    SciTech Connect (OSTI)

    Maingi, Rajesh; Mansfield, D. K.; Gong, X. Z.; Sun, Z.; Bell, M. G.

    2014-10-01

    In this paper, the role of lithium wall conditioning on the achievement of high performance, long pulse discharges in the National Spherical Torus Experiment (NSTX) and the Experimental Advanced Superconducting Tokamak (EAST) is documented. Common observations include recycling reduction and elimination of ELMs. In NSTX, lithium conditioning typically resulted in ELM-free operation with impurity accumulation, which was ameliorated e.g. with pulsed 3D fields to trigger controlled ELMs. Active lithium conditioning in EAST discharges has overcome this problem, producing an ELM-free Hmode with controlled density and impurities.

  10. The topology and polarization of sub-beams associated with the `drifting' sub-pulse emission of pulsar B0943110 I. Analysis of Arecibo 430-and

    E-Print Network [OSTI]

    Rankin, Joanna

    and Joanna M. Rankin2w 1 Raman Research Institute, Bangalore 560 080, India 2 Physics Department, University a transition from the highly organized `B' profile mode of the star to its disorganized `Q' mode; a 1972 430); rankin@physics.uvm.edu (JMR) #12;and sub-pulse `memory' ± in terms of fundamental emission pro- cesses

  11. Long-term developments in Her X-1: Correlation between the histories of the 35 day turn-on cycle and the 1.24 sec pulse period

    E-Print Network [OSTI]

    R. Staubert; S. Schandl; D. Klochkov; J Wilms; K. Postnov; N. Shakura

    2007-02-20

    We have studied the long-term (1971-2005) behaviour of the 1.24 sec pulse period and the 35 day precession period of Her X-1 and show that both periods vary in a highly correlated way (see also Staubert et al. 1997 and 2000). When the spin-up rate decreases, the 35 day turn-on period shortens.This correlation is most evident on long time scales (~2000 days),e.g.around four extended spin-down episodes, but also on shorter time scales (a few 100 days) on which quasi-periodic variations are apparent. We argue that the likely common cause is variations of the mass accretion rate onto the neutron star.The data since 1991 allow a continuous sampling and indicate a lag between the turn-on behaviour and the spin behaviour, in the sense that changes are first seen in the spin, about one cycle later in the turn-on. Both the coronal wind model (Schandl & Meyer 1994) as well as the stream-disk model (Shakura et al.999) predict this kind of behaviour.

  12. Pulse transmission receiver with higher-order time derivative pulse correlator

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-16

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  13. Containment failure time and mode for a low-pressure short-term station blackout in a BWR-4 with Mark-I containment

    SciTech Connect (OSTI)

    Carbajo, J.J.; Greene, S.R. (Oak Ridge National Lab., TN (United States))

    1993-01-01

    This study investigates containment failure time and mode for a low-pressure, short-term station blackout severe accident sequence in a boiling water reactor (BWR-4) with a Mark-I containment. The severe accident analysis code MELCOR, version 1.8.1, was used in these calculations. Other results using the MELCOR/CORBH package and the BWRSAR and CONTAIN codes are also presented and compared to the MELCOR results. The plant analyzed is the Peach Bottom atomic station, a BWR-4 with a Mark-I containment. The automatic depressurization system was used to depressurize the vessel in accordance with the Emergency Procedure Guidelines. Two different variations of the station blackout were studied: one with a dry cavity and the other with a flooded cavity. For the flooded cavity, it is assumed that a control rod drive (CRD) pump becomes operational after vessel failure, and it is used to pump water into the cavity.

  14. Preliminary study of pseudorandom binary sequence pulsing of ORELA

    SciTech Connect (OSTI)

    Larson, N. M.; Olsen, D. K.

    1980-03-01

    It has been suggested that pseudorandom binary sequence (PRBS) pulsing might enhance the performance of the Oak Ridge Electron Linear Accelerator (ORELA) for neutron-induced, time-of-flight (TOF) cross-section measurements. In this technical memorandum, equations are developed for expected count rates, statistical variances, and backgrounds for a pulsing scheme in which a PRBS is superimposed on the periodic equalintensity ORELA bursts. Introduction of the PRBS modification permits neutrons of different energies originating from different bursts to reach the detector simultaneously, and the signal corresponding to a unique flight time to be extracted mathematically. Relative advantages and disadvantages of measurements from conventional and PRBS pulsing modes are discussed in terms of counting statistics and backgrounds. Computer models of TOF spectra are generated for both pulsing modes, using as examples a 20-meter /sup 233/U fission-chamber measurement and a 155-meter /sup 238/U sample-in transmission measurement. Detailed comparisons of PRBS vs conventional results are presented. This study indicates that although PRBS pulsing could enhance ORELA performance for selected measurements, for general ORELA operation the disadvantages from PRBS pulsing probably outweigh the advantages.

  15. From quantum pulse gate to quantum pulse shaper -- enigneered frequency conversion in nonlinear optical waveguides

    E-Print Network [OSTI]

    Benjamin Brecht; Andreas Eckstein; Andreas Christ; Hubertus Suche; Christine Silberhorn

    2011-07-28

    Full control over the spatio-temporal structure of quantum states of light is an important goal in quantum optics, to generate for instance single-mode quantum pulses or to encode information on multiple modes, enhancing channel capacities. Quantum light pulses feature an inherent, rich spectral broadband-mode structure. In recent years, exploring the use of integrated optics as well as source-engineering has led to a deep understanding of the pulse-mode structure of guided quantum states of light. In addition, several groups have started to investigate the manipulation of quantum states by means of single-photon frequency conversion. In this paper we explore new routes towards complete control of the inherent pulse-modes of ultrafast pulsed quantum states by employing specifically designed nonlinear waveguides with adapted dispersion properties. Starting from our recently proposed quantum pulse gate (QPG) we further generalize the concept of spatio-spectral engineering for arbitrary $\\chitwo$-based quantum processes. We analyse the sum-frequency generation based QPG and introduce the difference-frequency generation based quantum pulse shaper (QPS). Together, these versatile and robust integrated optics devices allow for arbitrary manipulations of the pulse-mode structure of ultrafast pulsed quantum states. The QPG can be utilized to select an arbitrary pulse mode from a multimode input state, whereas the QPS enables the generation of specific pulse modes from an input wavepacket with Gaussian-shaped spectrum.

  16. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, H.A. Jr.

    1984-01-01

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  17. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, Jr., Herbert A. (Oak Ridge, TN)

    1985-01-01

    In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

  18. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    SciTech Connect (OSTI)

    Li, Lee Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-14

    Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

  19. Pulse transmission transceiver architecture for low power communications

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-05

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A method of pulse transmission communications includes: generating a modulated pulse signal waveform; transforming said modulated pulse signal waveform into at least one higher-order derivative waveform; and transmitting said at least one higher-order derivative waveform as an emitted pulse. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  20. Pulse stretcher

    DOE Patents [OSTI]

    Horton, J.A.

    1994-05-03

    Apparatus for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse is disclosed. The apparatus uses a White cell having a plurality of optical delay paths of successively increasing number of passes between the field mirror and the objective mirrors. A pulse from a laser travels through a multi-leg reflective path between a beam splitter and a totally reflective mirror to the laser output. The laser pulse is also simultaneously injected through the beam splitter to the input mirrors of the optical delay paths. The pulses from the output mirrors of the optical delay paths go simultaneously to the laser output and to the input mirrors of the longer optical delay paths. The beam splitter is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output. 6 figures.

  1. Pacific and Atlantic herring produce burst pulse

    E-Print Network [OSTI]

    Dill, Lawrence M.

    Pacific and Atlantic herring produce burst pulse sounds Ben Wilson1,2* , Robert S. Batty3 wild-caught herring. Pacific herring pro- duce distinctive bursts of pulses, termed Fast Repetitive Tick (FRT) sounds. These trains of broadband pulses (1.7­22 kHz) lasted between 0.6 s and 7.6 s. Most

  2. 838 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 42, NO. 8, AUGUST 2006 50-GHz Passively Mode-Locked Surface-Emitting

    E-Print Network [OSTI]

    Keller, Ursula

    designs. The experimental setup is very versatile and its design and construction are discussed in detail. Index Terms--Mode locking, pulsed lasers, semiconductor lasers, thermal lens. I. INTRODUCTION can be fabricated cost-effectively by wafer-scale mass production. With an eye on the 100-GHz mark

  3. Closed-loop pulsed helium ionization detector

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.

  4. EIGHT CHANNEL PROGRAMMABLE PULSE GENERATOR

    E-Print Network [OSTI]

    Kleinfeld, David

    Master-8 EIGHT CHANNEL PROGRAMMABLE PULSE GENERATOR Operation Manual A.M.P.I. A.M.P.I. 123Uzlel St and the programming simple and easy to learn. Master-8 is an attractive unit and you will enjoy working with its eight -- Modes of operation 11 -- Setting the parameters 13 -- Triggering 14 -- Eight stored paradigms 14

  5. Development of high-voltage pulse-slicer unit with variable pulse duration for pulse radiolysis system

    SciTech Connect (OSTI)

    Upadhyay, J.; Sharma, M. L.; Navathe, C. P. [Laser Electronic Support Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Toley, M. A.; Shinde, S. J.; Nadkarni, S. A.; Sarkar, S. K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-02-15

    A high-voltage pulse-slicer unit with variable pulse duration has been developed and integrated with a 7 MeV linear electron accelerator (LINAC) for pulse radiolysis investigation. The pulse-slicer unit provides switching voltage from 1 kV to 10 kV with rise time better than 5 ns. Two MOSFET based 10 kV switches were configured in differential mode to get variable duration pulses. The high-voltage pulse has been applied to the deflecting plates of the LINAC for slicing of electron beam of 2 {mu}s duration. The duration of the electron beam has been varied from 30 ns to 2 {mu}s with the optimized pulse amplitude of 7 kV to get corresponding radiation doses from 6 Gy to 167 Gy.

  6. Low-noise pulse conditioner

    DOE Patents [OSTI]

    Bird, D.A.

    1981-06-16

    A low-noise pulse conditioner is provided for driving electronic digital processing circuitry directly from differentially induced input pulses. The circuit uses a unique differential-to-peak detector circuit to generate a dynamic reference signal proportional to the input peak voltage. The input pulses are compared with the reference signal in an input network which operates in full differential mode with only a passive input filter. This reduces the introduction of circuit-induced noise, or jitter, generated in ground referenced input elements normally used in pulse conditioning circuits, especially speed transducer processing circuits. This circuit may be used for conditioning the sensor signal from the Fidler coil in a gas centrifuge for separation of isotopic gaseous mixtures.

  7. System and process for pulsed multiple reaction monitoring

    DOE Patents [OSTI]

    Belov, Mikhail E

    2013-05-17

    A new pulsed multiple reaction monitoring process and system are disclosed that uses a pulsed ion injection mode for use in conjunction with triple-quadrupole instruments. The pulsed injection mode approach reduces background ion noise at the detector, increases amplitude of the ion signal, and includes a unity duty cycle that provides a significant sensitivity increase for reliable quantitation of proteins/peptides present at attomole levels in highly complex biological mixtures.

  8. October 1, 2003 / Vol. 28, No. 19 / OPTICS LETTERS 1835 Picosecond-pulse amplification with an external

    E-Print Network [OSTI]

    Xie, Xiaoliang Sunney

    of generating high-repetition-rate pulse trains (250 kHz) with microjoule pulse energies.2 Alternatively, pulses-locked picosecond Ti:sapphire laser to pulse energies of more than 150 nJ. © 2003 Optical Society of America OCIS codes: 320.7080, 140.4480, 300.6220. The nanojoule-scale pulse energies obtained directly from a mode

  9. Multi-dimensional laser mode combs (mode hyper-combs)

    E-Print Network [OSTI]

    Schwartz, Alon

    2012-01-01

    Laser frequency combs, as most lasers, are one-dimensional. Here we present a realization of d-dimensional laser mode lattices (mode hyper-combs) with unique properties. They are constructed from regular 1-dimensional combs by multi-frequency modulation in active mode-locking (AML). The hyper-comb, with near neighbor mode interaction and noise functioning as temperature, is mapped to interacting magnetic spin-lattices in the spherical-model, which is one of the few statistical-mechanics systems soluble in all dimensions. The important result is that such systems have, in d>2 dimensions, a phase-transition to a global mode-phase-ordered hyper-comb. It changes the nature of AML lasers, giving ultimately short and robust pulses which can capture very broad frequency bandwidths. Additionally, the hyper-combs can serve as a rare physical realization of the spherical-model in any dimension.

  10. Pulsed hydrojet

    DOE Patents [OSTI]

    Bohachevsky, I.O.; Torrey, M.D.

    1986-06-10

    An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

  11. Source term evaluation for postulated UF{sub 6} release accidents in gaseous diffusion plants -- Summer ventilation mode (non-seismic cases)

    SciTech Connect (OSTI)

    Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Wendel, M.W.; Keith, K.D.; Schmidt, R.W. [Oak Ridge National Lab., TN (United States); Carter, J.C. [J.C. Carter Associates, Inc., Knoxville, TN (United States); Dyer, R.H. [Dyer Enterprises, Harriman, TN (United States)

    1996-12-30

    Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a postulated accident involving the release of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant. For the current study, gaseous UF{sub 6} is assumed to get released in the cell housing atmosphere through B-line break at 58.97 kg/s for 10 min and 30 min duration at the Paducah and Portsmouth Gaseous Diffusion Plants. The released UF{sub 6} undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form hydrogen fluoride (HF) and radioactive uranyl fluoride (UO{sub 2}F{sub 2}) while it disperses throughout the process building. As part of a facility-wide safety evaluation, this study evaluated source terms consisting of UO{sub 2}F{sub 2} as well as HF during a postulated UF{sub 6} release accident in a process building. UO{sub 2}F{sub 2} mainly remains as airborne-solid particles (aerosols), and HF is in a vapor form. Some UO{sub 2}F{sub 2} aerosols are removed from the air flow due to gravitational settling. The HF and the remaining UO{sub 2}F{sub 2} are mixed with air and exhausted through the building ventilation system. The MELCOR computer code was selected for simulating aerosols and vapor transport in the process building. To characterize leakage flow through the cell housing wall, 3-D CFD tool (CFDS-FLOW3D) was used. About 57% of UO{sub 2}F{sub 2} was predicted to be released into the environment. Since HF was treated as vapor, close to 100% was estimated to get released into the environment.

  12. Pulse transmission receiver with higher-order time derivative pulse generator

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-12

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a front-end amplification/processing circuit; a synchronization circuit coupled to the front-end amplification/processing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  13. Fast pulsed excitation wiggler or undulator

    DOE Patents [OSTI]

    van Steenbergen, Arie (Shoreham, NY)

    1990-01-01

    A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

  14. Excitation of two atoms by a propagating single photon pulse

    E-Print Network [OSTI]

    Navneeth Ramakrishnan; Yimin Wang; Valerio Scarani

    2014-11-13

    We describe the interaction of two two-level atoms in free space with propagating modes of the quantized electromagnetic field, using the time-dependent Heisenberg-Langevin method. For single- photon pulses, we consider the effect of the pulse's spatial and temporal profiles on the atomic excitation. In particular, we find the ideal shape for a pulse to put exactly one excitation in any desired state of the bi-atomic system. Furthermore, we analyze the differences in the atomic dynamics between the cases of Fock state pulses and coherent state pulses.

  15. Fault tolerant pulse synchronization 

    E-Print Network [OSTI]

    Deconda, Keerthi

    2009-05-15

    Pulse synchronization is the evolution of spontaneous firing action across a network of sensor nodes. In the pulse synchronization model all nodes across a network produce a pulse, or "fire", at regular intervals even without access to a shared...

  16. Pulse transmission transmitter including a higher order time derivate filter

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-23

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission transmitter includes: a clock; a pseudorandom polynomial generator coupled to the clock, the pseudorandom polynomial generator having a polynomial load input; an exclusive-OR gate coupled to the pseudorandom polynomial generator, the exclusive-OR gate having a serial data input; a programmable delay circuit coupled to both the clock and the exclusive-OR gate; a pulse generator coupled to the programmable delay circuit; and a higher order time derivative filter coupled to the pulse generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  17. Long pulse production from short pulses

    DOE Patents [OSTI]

    Toeppen, J.S.

    1994-08-02

    A method of producing a long output pulse from a short pump pulse is disclosed, using an elongated amplified fiber having a doped core that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding. A seed beam of the longer wavelength is injected into the core at one end of the fiber and a pump pulse of the shorter wavelength is injected into the cladding at the other end of the fiber. The counter-propagating seed beam and pump pulse will produce an amplified output pulse having a time duration equal to twice the transit time of the pump pulse through the fiber plus the length of the pump pulse. 3 figs.

  18. Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption

    SciTech Connect (OSTI)

    Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2014-06-15

    The early stage of formation of lithium plasma in a collinear—double pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8?nm and 610.3?nm), and ionic (548.4?nm and 478.8?nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

  19. Pulse-like and crack-like ruptures in experiments mimicking crustal earthquakes

    E-Print Network [OSTI]

    Lapusta, Nadia

    Pulse-like and crack-like ruptures in experiments mimicking crustal earthquakes Xiao Lu , Nadia ruptures may propagate in a self-healing pulse-like mode. A number of expla- nations for the existence of slip pulses have been proposed and continue to be vigorously debated. This study presents experimen

  20. Properties of water surface discharge at different pulse repetition rates

    SciTech Connect (OSTI)

    Ruma,; Yoshihara, K. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Hosseini, S. H. R., E-mail: hosseini@kumamoto-u.ac.jp; Sakugawa, T.; Akiyama, H. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Akiyama, M. [Department of Electrical and Electronic Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Lukeš, P. [Institute of Plasma Physics, AS CR, Prague, Prague 18200 (Czech Republic)

    2014-09-28

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H?O?) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H?O? and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  1. Musical pulse tracking algorithms and applications

    E-Print Network [OSTI]

    Saxton, Ian Arnold

    2008-01-01

    4.1.1. Pulse-Human Pulse Inference . . . . . . . . . . . . . . . . . .Phase Consistency Pulse Tracker . . . . . . . . . . . . .

  2. Hybrid mode-locking in a 40 GHz monolithic quantum dot laser G. Fiol,1,a

    E-Print Network [OSTI]

    Vladimirov, Andrei G.

    Hybrid mode-locking in a 40 GHz monolithic quantum dot laser G. Fiol,1,a D. Arsenijevi,1 D. Bimberg; accepted 30 November 2009; published online 5 January 2010 Hybrid mode-locking in monolithic quantum dot QD of hybrid mode-locking ML , a commonly used technique for improving quality of mode- locked pulses

  3. Laser pulse stacking method

    DOE Patents [OSTI]

    Moses, E.I.

    1992-12-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  4. Mode Analyses

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGEMission Mission Missionof EnergyJennings= a nMode Analyses

  5. Investigation of mode coupling in normal-dispersion silicon nitride microresonators

    E-Print Network [OSTI]

    Purdue University

    -dispersion devices highlight mode interactions as a beneficial tool for comb initiation and pulse formation. © 2014Investigation of mode coupling in normal- dispersion silicon nitride microresonators for Kerr microresonators are the subject of intense study for potential applications ranging from short pulse generation

  6. A THz transverse electromagnetic mode two-dimensional interconnect layer incorporating quasi-optics

    E-Print Network [OSTI]

    of transmitting subpicosecond pulses in the transverse electromagnetic TEM mode over arbitrarily long paths near the cutoff fre- quency. Such pulse broadening does not occur for the trans- verse electromagneticA THz transverse electromagnetic mode two-dimensional interconnect layer incorporating quasi

  7. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  8. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  9. Hybrid chirped pulse amplification system

    DOE Patents [OSTI]

    Barty, Christopher P.; Jovanovic, Igor

    2005-03-29

    A hybrid chirped pulse amplification system wherein a short-pulse oscillator generates an oscillator pulse. The oscillator pulse is stretched to produce a stretched oscillator seed pulse. A pump laser generates a pump laser pulse. The stretched oscillator seed pulse and the pump laser pulse are directed into an optical parametric amplifier producing an optical parametric amplifier output amplified signal pulse and an optical parametric amplifier output unconverted pump pulse. The optical parametric amplifier output amplified signal pulse and the optical parametric amplifier output laser pulse are directed into a laser amplifier producing a laser amplifier output pulse. The laser amplifier output pulse is compressed to produce a recompressed hybrid chirped pulse amplification pulse.

  10. Pulse enhanced fluidized bed combustion

    SciTech Connect (OSTI)

    Mueller, B.

    1996-12-31

    Information is outlined on pulse enhanced fluidized bed combustion. The following topics are discussed: what is pulse enhanced fluidized bed combustion?; pulse combustors; pulsed atmospheric fluidized bed combustor (PAFBC); advantages of PAFBC; performance advantages; PAFBC facts; and PAFBC contact points.

  11. Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

    DOE Patents [OSTI]

    Thompson, Donald O. (Ames, IA); Hsu, David K. (Ames, IA)

    1993-12-14

    The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses.

  12. Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

    DOE Patents [OSTI]

    Thompson, D.O.; Hsu, D.K.

    1993-12-14

    The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses. 25 figures.

  13. Topological modes driven by Lyapunov control

    E-Print Network [OSTI]

    Z. C. Shi; X. L. Zhao; X. X. Yi

    2014-11-20

    By Lyapunov control, we present a proposal to drive quasiparticles into a topological mode in quantum systems described by quadratic Hamiltonian. The merit of this control strategy is that only manipulation of the boundary sites are required, and the proposal works for both Fermi and Bose systems. We take the Kitaev's chain as an illustration for Fermi system and show that by manipulating the chemical potential of the boundary sites, we can steer an arbitrary excitation mode into the Majorana zero mode. For Bose system, taking the noninteracting Su-Schrieffer-Heeger (SSH) model as an example, we illustrate how to drive the system into the edge mode, i.e., the mode localized at the boundary sites. Finally, we explore the possibility to replace the continuous control field by square wave pulses.

  14. High voltage pulse conditioning

    DOE Patents [OSTI]

    Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  15. Self-starting of passive mode locking Ariel Gordon1,2, Omri Gat1,3, Baruch Fischer1 and Franz X. Kartner2

    E-Print Network [OSTI]

    Fischer, Baruch

    transition in a system of many interacting light modes subject to noise. In the same framework, self starting Theory of Many-Mode Ordering and Pulse Formation in Lasers", Phys. Rev. Lett. 89, 103901, (2002) 16. A. Gordon and B. Fischer, Phase transition theory of pulse formation in passively mode-locked lasers

  16. Pulse compression in plasma: generation of femtosecond pulses without CPA

    E-Print Network [OSTI]

    Pulse compression in plasma: generation of femtosecond pulses without CPA G. Shvets and N. J. Fisch Garching, Germany Abstract: Laser pulses can be e#ciently compressed to femto­ second duration when a smaller­ frequency short pulse collides with high frequency long pulse in rare plasma, absorbing most

  17. Photonic generation of UWB pulses with pulse position modulation

    E-Print Network [OSTI]

    Yao, Jianping

    Photonic generation of UWB pulses with pulse position modulation H. Mu and J. Yao A novel photonic approach to generating ultra-wideband (UWB) signals with pulse position modulation (PPM) is proposed delay-line filter for UWB monocycle pulse generation, the second subsystem being a pulse

  18. Cold Flow Simulations for a Pulse Detonation Rocket Ejector J. Tyler Nichols, Donald R. Wilson, Frank K. Lu

    E-Print Network [OSTI]

    Texas at Arlington, University of

    supersonic Mach numbers (2) A pulsed normal detonation wave mode at combustion chamber Mach numbers less thanCold Flow Simulations for a Pulse Detonation Rocket Ejector J. Tyler Nichols, Donald R. Wilson pulse detonation rocket (PDR) ejecting into a duct was fabricated and integrated into the supersonic

  19. IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 17, NO. 12, DECEMBER 2005 2733 Width and Wavelength-Tunable Optical RZ Pulse

    E-Print Network [OSTI]

    Purdue University

    -Tunable Optical RZ Pulse Generation and RZ-to-NRZ Format Conversion at 10 GHz Using Spectral Line-by-Line Control, IEEE Abstract--We demonstrate a method for tunable optical return- to-zero (RZ) pulse generation on spectral line-by-line pulse shaping of a wavelength- tunable mode-locked laser. All-optical RZ

  20. Model for passive mode locking in semiconductor lasers Andrei G. Vladimirov*

    E-Print Network [OSTI]

    Vladimirov, Andrei G.

    Model for passive mode locking in semiconductor lasers Andrei G. Vladimirov* Weierstrass Institute 11 May 2005; published 12 September 2005 We derive and study a model describing passive mode locking.65.Pc INTRODUCTION Passive mode locking ML is a powerful method to gen- erate high-quality short pulses

  1. Heat pulse propagation in chaotic three-dimensional magnetic fields

    SciTech Connect (OSTI)

    Del-Castillo-Negrete, Diego [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Blazevski, Daniel [Institute for Mechanical Systems, ETH, Zurich (Switzerland)

    2014-06-01

    Heat pulse propagation in three-dimensional chaotic magnetic fields is studied by numerically solving the parallel heat transport equation using a Lagrangian Green's function (LG) method. The main two problems addressed are: the dependence of the radial transport of heat pulses on the level of magnetic field stochasticity (controlled by the amplitude of the magnetic field perturbation, ?), and the role of reversed shear magnetic field configurations on heat pulse propagation. The role of separatrix reconnection of resonant modes in the shear reversal region, and the role of shearless Cantori in the observed phenomena are also discussed.

  2. Long pulse EBW start-up experiments in MAST

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

    Shevchenko, V. F.; Baranov, Y. F.; Bigelow, T.; Caughman, J. B.; Diem, S.; Dukes, C.; Finburg, P.; Hawes, J.; Gurl, C.; Griffiths, J.; et al

    2015-03-12

    Start-up technique reported here relies on a double mode conversion (MC) for electron Bernstein wave (EBW) excitation. It consists of MC of the ordinary (O) mode, entering the plasma from the low field side of the tokamak, into the extraordinary (X) mode at a mirror-polarizer located at the high field side. The X mode propagates back to the plasma, passes through electron cyclotron resonance (ECR) and experiences a subsequent X to EBW MC near the upper hybrid resonance (UHR). Finally the excited EBW mode is totally absorbed at the Doppler shifted ECR. The absorption of EBW remains high even inmore »cold rarefied plasmas. Furthermore, EBW can generate significant plasma current giving the prospect of a fully solenoid-free plasma start-up. First experiments using this scheme were carried out on MAST [1]. Plasma currents up to 33 kA have been achieved using 28 GHz 100kW 90ms RF pulses. Recently experimental results were extended to longer RF pulses showing further increase of plasma currents generated by RF power alone. A record current of 73kA has been achieved with 450ms RF pulse of similar power. The current drive enhancement was mainly achieved due to RF pulse extension and further optimisation of the start-up scenario.« less

  3. Mode Selective Excitation Using Coherent Control Spectroscopy

    SciTech Connect (OSTI)

    Singh, Ajay K.; Konradi, Jakow; Materny, Arnulf; Sarkar, Sisir K.

    2008-11-14

    Femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) gives access to ultrafast molecular dynamics. However, femtosecond laser pulses are spectrally broad and therefore coherently excite several molecular modes. While the temporal resolution is high, usually no mode-selective excitation is possible. This paper demonstrates the feasibility of selectively exciting specific molecular vibrations in solution phase with shaped fs laser excitation using a feedback-controlled optimization technique guided by an evolutionary algorithm. This approach is also used to obtain molecule-specific CARS spectra from a mixture of different substances. The optimized phase structures of the fs pulses are characterized to get insight into the control process. Possible applications of the spectrum control are discussed.

  4. Short-pulse chirped adiabatic population transfer in diatomic molecules S. Kallush and Y. B. Band

    E-Print Network [OSTI]

    Band, Yehuda B.

    Short-pulse chirped adiabatic population transfer in diatomic molecules S. Kallush and Y. B. Band electronic states to a second electronic state. Our chirped-pulse rapid adiabatic passage scheme is implemented with short-duration optical pulses, and can be understood in terms of ``road design engineering

  5. Classical Dynamics of Free Electromagnetic Laser Pulses

    E-Print Network [OSTI]

    Goto, S; Walton, T J

    2015-01-01

    We discuss a class of exact finite energy solutions to the vacuum source-free Maxwell field equations as models for multi- and single cycle laser pulses in classical interaction with relativistic charged test particles. These solutions are classified in terms of their chiral content based on their influence on particular charge configurations in space. Such solutions offer a computationally efficient parameterization of compact laser pulses used in laser-matter simulations and provide a potential means for experimentally bounding the fundamental length scale in the generalized electrodynamics of Bopp, Lande and Podolsky.

  6. Classical Dynamics of Free Electromagnetic Laser Pulses

    E-Print Network [OSTI]

    S. Goto; R. W. Tucker; T. J. Walton

    2015-08-21

    We discuss a class of exact finite energy solutions to the vacuum source-free Maxwell field equations as models for multi- and single cycle laser pulses in classical interaction with relativistic charged test particles. These solutions are classified in terms of their chiral content based on their influence on particular charge configurations in space. Such solutions offer a computationally efficient parameterization of compact laser pulses used in laser-matter simulations and provide a potential means for experimentally bounding the fundamental length scale in the generalized electrodynamics of Bopp, Lande and Podolsky.

  7. Long Pulse Modulators

    E-Print Network [OSTI]

    Eckoldt, J

    2015-01-01

    Long pulse modulators are used to produce high-voltage, high-power pulses with durations of several hundred microseconds up to some milliseconds. The loads are one or more klystrons for producing RF power to accelerate the particle beam in superconducting cavities. After years of development and improvements in different institutes a variety of topologies exist, and are presented. The basics of modulators, pulse requirements and klystrons are explained. Additionally, the charging of internal energy storage will be addressed. The outlook for future developments is given.

  8. Mode propagation and attenuation in lined ducts

    E-Print Network [OSTI]

    BI, Wenping

    2014-01-01

    Optimal impedance for each mode is an important concept in an infinitely long duct lined with uniform absorption material. However it is not valid for finite length linings. This is because that the modes in lined ducts are not power-orthogonal; the total sound power is not equal to the sum of the sound power of each mode; cross-power terms may play important roles. In this paper, we study sound propagation and attenuation in an infinite rigid duct lined with a finite length of lining impedance. The lining impedance may be axial segments and circumferentially non-uniform. We propose two new physical quantities Kp and S to describe the self-overlap of the left eigenfunction and right eigenfunction of one mode and the normalized overlap between modes, respectively. The two new physical quantities describe totally the mode behaviors in lined ducts.

  9. Pulse measurement apparatus and method

    DOE Patents [OSTI]

    Marciante, John R. (Webster, NY); Donaldson, William R. (Pittsford, NY); Roides, Richard G. (Scottsville, NY)

    2011-10-25

    An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

  10. Digital pulse processing

    E-Print Network [OSTI]

    McCormick, Martin (Martin Steven)

    2012-01-01

    This thesis develops an exact approach for processing pulse signals from an integrate-and-fire system directly in the time-domain. Processing is deterministic and built from simple asynchronous finite-state machines that ...

  11. Studies of Charge Exchange in a High?Pressure Pulsed Electron Impact Source

    E-Print Network [OSTI]

    Sharma, D. K. Sen; Hierl, Peter M.; Franklin, J. L.

    1972-01-01

    A high pressure pulsed ion source has been used in a time?of?flight mass spectrometer in order to study the charge exchangereactions in Ar–H2 and Ar–D2 systems using the ion source in the ?ermák mode of operation. As the source was used in a pulsed...

  12. Pulsed Zeeman spectroscopy 

    E-Print Network [OSTI]

    Cullen, Raymond Paul

    1967-01-01

    PULSED ZEEMAN SPECTROSCOPY A Thesis Raymond P. Cullen Submitted to the Graduate Collepe of the Texas MM University in partial fulfillment of the requirements for the degree of MASTER OE SCIENCE August 1967 Major Subject: Chemistry PULSRD... ZEEHA&'I SPRCTPOSC::)Py A The. ", is by Raymond P. Cullen Approved es to style and content by: (Chairman o~ Commi. tee) August 1967 Pulsed Zceman Spectroscopy (August 1967) Raymond P. Cullen, B. S. , Texas A6M University Directed by: Dr...

  13. Pulse magnetic welder

    DOE Patents [OSTI]

    Christiansen, D.W.; Brown, W.F.

    1984-01-01

    A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.

  14. Pulse combustion: Commercial, industrial, and residential applications. (Latest citations from the NTIS Bibliographic database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-10-01

    The bibliography contains citations concerning the evolution of pulse combustion, the types of pulse combustion burners and their applications, and selected fuels utilized. Topics include fuel combustion efficiency, energy conversion and utilization technologies, modeling of chemical kinetics, and dynamics and thermal characteristics of pulse combustors. Pulse combustion systems for water heaters, gas furnaces, industrial and residential boilers, commercial cooking equipment, and space heating devices are presented. (Contains 250 citations and includes a subject term index and title list.)

  15. Pulse shaping with transmission lines

    DOE Patents [OSTI]

    Wilcox, Russell B. (Oakland, CA)

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  16. Efficient optical pulse stacker system

    DOE Patents [OSTI]

    Seppala, Lynn G. (Pleasanton, CA); Haas, Roger A. (Pleasanton, CA)

    1982-01-01

    Method and apparatus for spreading and angle-encoding each pulse of a multiplicity of small area, short pulses into several temporally staggered pulses by use of appropriate beam splitters, with the optical elements being arranged so that each staggered pulse is contiguous with one or two other such pulses, and the entire sequence of stacked pulses comprising a single, continuous long pulse. The single long pulse is expanded in area, and then doubly passed through a nonstorage laser amplifier such as KrF. After amplification, the physically separated, angle-encoded and temporally staggered pulses are recombined into a single pulse of short duration. This high intensity output beam is well collimated and may be propagated over long distance, or used for irradiating inertial confinement fusion targets.

  17. Photoconductive circuit element pulse generator

    DOE Patents [OSTI]

    Rauscher, Christen (Alexandria, VA)

    1989-01-01

    A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

  18. QUADRATURE CLOCK CONVERTER X1 and X4 mode selection

    E-Print Network [OSTI]

    Wedeward, Kevin

    -level selects the X1 mode. In X4 mode, an output pulse is generated for every transition at either A or B input indication output. When A input leads the B input, the UP/DN output goes high indicating that the count 0.7VDD - V - A,B Logic High VIH 3.1 - V VDD = 4.75V 5.0 - V VDD = 9V 5.6 - V VDD = 10.5V ALL OUTPUTS

  19. IEEE JOURNAL ON SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 8, NO. 3, MAY/JUNE 2002 591 Multichannel Soliton Transmission and Pulse

    E-Print Network [OSTI]

    Multichannel Soliton Transmission and Pulse Shepherding in Bit-Parallel-Wavelength Optical Fiber Links Elena A principles of the bit-parallel-wave- length (BPW) pulse transmission in multichannel single-mode op- tical fiber links for high-performance computer networks. We de- velop a theory of the pulse shepherding

  20. Pulse shaping system

    DOE Patents [OSTI]

    Skeldon, Mark D. (Penfield, NY); Letzring, Samuel A. (Jemez Springs, NM)

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

  1. Pulsed neutron detector

    DOE Patents [OSTI]

    Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

    1989-03-21

    A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

  2. Laser pulse sampler

    DOE Patents [OSTI]

    Vann, C.

    1998-03-24

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera. 5 figs.

  3. Laser pulse sampler

    DOE Patents [OSTI]

    Vann, Charles (Fremont, CA)

    1998-01-01

    The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera.

  4. Pulse shaping system

    DOE Patents [OSTI]

    Skeldon, M.D.; Letzring, S.A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

  5. American Institute of Aeronautics and Astronautics A Pulsed Detonation Based Multimode Engine

    E-Print Network [OSTI]

    Texas at Arlington, University of

    was powered by the NASP propulsion system concept (scaled up to the size required for this 'payload capable numbers (2) A pulsed normal detonation wave mode at combustion chamber Mach numbers less than the Chapman-Jouguet Mach number, (3) An oblique detonation wave mode of operation for Mach numbers in the airbreathing

  6. SNMR pulse sequence phase cycling

    DOE Patents [OSTI]

    Walsh, David O; Grunewald, Elliot D

    2013-11-12

    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

  7. Observable primordial vector modes

    E-Print Network [OSTI]

    Antony Lewis

    2004-06-04

    Primordial vector modes describe vortical fluid perturbations in the early universe. A regular solution exists with constant non-zero radiation vorticities on super-horizon scales. Baryons are tightly coupled to the photons, and the baryon velocity only decays by an order unity factor by recombination, leading to an observable CMB anisotropy signature via the Doppler effect. There is also a large B-mode CMB polarization signal, with significant power on scales larger than l~2000. This B-mode signature is distinct from that expected from tensor modes or gravitational lensing, and makes a primordial vector to scalar mode power ratio ~10^(-6) detectable. Future observations aimed at detecting large scale B-modes from gravitational waves will also be sensitive to regular vector modes at around this level.

  8. Downhole pulse tube refrigerators

    SciTech Connect (OSTI)

    Swift, G.; Gardner, D.

    1997-12-01

    This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

  9. Analog pulse processor

    DOE Patents [OSTI]

    Wessendorf, Kurt O.; Kemper, Dale A.

    2003-06-03

    A very low power analog pulse processing system implemented as an ASIC useful for processing signals from radiation detectors, among other things. The system incorporates the functions of a charge sensitive amplifier, a shaping amplifier, a peak sample and hold circuit, and, optionally, an analog to digital converter and associated drivers.

  10. Nondegenerate optical parametric chirped pulse amplifier

    DOE Patents [OSTI]

    Jovanovic, Igor; Ebbers, Christopher A.

    2005-03-22

    A system provides an input pump pulse and a signal pulse. A first dichroic beamsplitter is highly reflective for the input signal pulse and highly transmissive for the input pump pulse. A first optical parametric amplifier nonlinear crystal transfers part of the energy from the input pump pulse to the input signal pulse resulting in a first amplified signal pulse and a first depleted pump pulse. A second dichroic beamsplitter is highly reflective for the first amplified signal pulse and highly transmissive for the first depleted pump pulse. A second optical parametric amplifier nonlinear crystal transfers part of the energy from the first depleted pump pulse to the first amplified signal pulse resulting in a second amplified signal pulse and a second depleted pump pulse. A third dichroic beamsplitter receives the second amplified signal pulse and the second depleted pump pulse. The second depleted pump pulse is discarded.

  11. Fields of an ultrashort tightly-focused laser pulse

    E-Print Network [OSTI]

    Li, Jian-Xing; Hatsagortsyan, Karen Z; Keitel, Christoph H

    2015-01-01

    Analytic expressions for the electromagnetic fields of an ultrashort, tightly focused, laser pulse in vacuum are derived from scalar and vector potentials, using on equal footing two small parameters connected with the waist size of the laser beam and its duration. Compared with fields derived from a complex-source-point approach and a Lax series expansion approach, the derived fields are shown to be well-behaved and accurate even in the subcycle pulse regime. Terms stemming from the scalar potential are shown to be non-negligible and could significantly influence laser-matter interactions, in particular, direct electron acceleration in vacuum by an ultrashort laser pulse.

  12. High-power pulse trains excited by modulated continuous waves

    E-Print Network [OSTI]

    Wang, Yan; Li, Lu; Malomed, Boris A

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.

  13. Sequentially pulsed traveling wave accelerator

    DOE Patents [OSTI]

    Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  14. Optomechanical Entanglement under Pulse Drive

    E-Print Network [OSTI]

    Qing Lin; Bing He

    2015-08-12

    We report a study of optomechanical entanglement under the drive of one or a series of laser pulses with arbitrary detuning and different pulse shapes. Because of the non-existence of system steady state under pulsed driving field, we adopt a different approach from the standard treatment to optomechanical entanglement. The situation of the entanglement evolution in high temperature is also discussed.

  15. Mixed-mode cooling.

    E-Print Network [OSTI]

    Brager, Gail

    2006-01-01

    ASHRAE’s permission. Mixed-Mode Cooling Photo Credit: Paulnatural ventilation for cooling. Buildings typically had1950s of large-scale mechanical cooling, along with other

  16. Cluster Compatibility Mode

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

    the needed runtime environment. Users can also compile codes for CCM on Hopper. All compilers available to Hopper's native programming environment (Extreme Scalability Mode, ESM...

  17. Application of pulse combustion to incineration to liquid hazardous waste. Final report, September 1991-August 1993

    SciTech Connect (OSTI)

    DeBenedictis, C.

    1994-04-01

    The report gives results of a study to determine the effect of acoustic pulsations on the steady-state operation of a pulse combuster burning liquid hazardous waste. A horizontal tunnel furnace was retrofitted with a liquid injection pulse combustor that burned No. 2 fuel oil. The fuel oil was doped with surrogate principal organic hazardous constituents (POHCs). For each test condition, the burner was operated in both a pulsing and nonpulsing mode. Large amplitude acoustic pulses were generated by adjusting the burner frequency to match the natural frequency of the combustion chamber. The combustion gases were sampled to quantify organic and particulate emissions. The results showed destruction and removal efficiency (DRE) values that were greater than six nines (99.9999%) for both pulsing and nonpulsing operations. The pulse combustor for the study was equipped with a fuel vaporization unit which may have enhanced the destruction capabilities of the burner.

  18. Numerical investigation of pulse-modulated atmospheric radio frequency discharges in helium under different duty cycles

    SciTech Connect (OSTI)

    Sun Jizhong; Ding Zhengfen; Li Xuechun; Wang Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Wang Qi [Dalian Institute of Semiconductor Technology, School of Electronics Science and Technology, Dalian University of Technology, Dalian 116023 (China)

    2011-12-15

    Experiments observed that the pulse duty cycle has effects on the plasma homogeneity in pulse-modulated radio frequency (rf) discharges. In this paper, pulse-modulated rf (13.56 MHz) helium discharges are theoretically investigated using a two dimensional fluid model. With the pulse period being fixed to 15 {mu}s, it is found that when the pulse-on duration is over 4 {mu}s, i.e., the duty cycle is larger than approximately 27%, the discharge transits from an inhomogeneous to a homogeneous mode in every specific part of each pulse cycle under currently-used simulation parameters. More quantitative analysis shows that the discharge becomes more homogeneous as the duty cycle is increased but does not reach complete homogeneity. Possible reasons for the homogeneity improvement are discussed.

  19. Pulsed gas laser

    DOE Patents [OSTI]

    Anderson, Louis W. (Madison, WI); Fitzsimmons, William A. (Madison, WI)

    1978-01-01

    A pulsed gas laser is constituted by Blumlein circuits wherein space metal plates function both as capacitors and transmission lines coupling high frequency oscillations to a gas filled laser tube. The tube itself is formed by spaced metal side walls which function as connections to the electrodes to provide for a high frequency, high voltage discharge in the tube to cause the gas to lase. Also shown is a spark gap switch having structural features permitting a long life.

  20. Instrument performance study on the short and long pulse options of the second Spallation Neutron Source target station

    SciTech Connect (OSTI)

    Zhao, J. K.; Herwig, Kenneth W.; Robertson, J. L.; Gallmeier, Franz X.; Riemer, Bernard W.

    2013-10-15

    The Spallation Neutron Source (SNS) facility at the Oak Ridge National Laboratory is designed with an upgrade option for a future low repetition rate, long wavelength second target station. This second target station is intended to complement the scientific capabilities of the 1.4 MW, 60 Hz high power first target station. Two upgrade possibilities have been considered, the short and the long pulse options. In the short pulse mode, proton extraction occurs after the pulse compression in the accumulator ring. The proton pulse structure is thus the same as that for the first target station with a pulse width of ?0.7 ?s. In the long pulse mode, protons are extracted as they are produced by the linac, with no compression in the accumulator ring. The time width of the uncompressed proton pulse is ?1 ms. This difference in proton pulse structure means that neutron pulses will also be different. Neutron scattering instruments thus have to be designed and optimized very differently for these two source options which will directly impact the overall scientific capabilities of the SNS facility. In order to assess the merits of the short and long pulse target stations, we investigated a representative suit of neutron scattering instruments and evaluated their performance under each option. Our results indicate that the short pulse option will offer significantly better performance for the instruments and is the preferred choice for the SNS facility.

  1. Excimer emission from pulsed microhollow cathode discharges in xenon

    SciTech Connect (OSTI)

    Lee, B.-J.; Nam, S. H. [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of)] [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of); Rahaman, H. [CSIR–CEERI Pilani, Rajasthan 333031 (India)] [CSIR–CEERI Pilani, Rajasthan 333031 (India); Iberler, M.; Jacoby, J. [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)] [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Frank, K. [Physics Department 1, University of Erlangen – Nuremberg, 91058 Erlangen (Germany)] [Physics Department 1, University of Erlangen – Nuremberg, 91058 Erlangen (Germany)

    2013-12-15

    Direct current (dc) microhollow cathode discharge (MHCD) is an intense source for excimer radiation in vacuum ultraviolet at a wavelength of 172 nm in a high pressure xenon (Xe) gas. The concentration of precursors for the excimer formation, i.e., excited and ionized gas atoms, increases significantly by applying high voltage pulse onto the dc MHCD over the pulse duration range from 20 to 100 ns. The intensity of the excimer emission for the voltage pulse of 20 ns duration exceeds that of the emission intensity obtained from the same MHCD operated only in the dc mode, by one order of magnitude. In addition, the emission intensity increases by one order of magnitude over the pulse duration range from 20 to 100 ns. It can be assumed that the emission intensity of the MHCD source increases as long as the duration of the high voltage pulse is shorter than the electron relaxation time. For the high voltage pulse of 100 ns duration, the emission intensity has been found to be further enhanced by a factor of three when the gas pressure is increased from 200 to 800 mbar.

  2. Petawatt pulsed-power accelerator

    DOE Patents [OSTI]

    Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

    2010-03-16

    A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

  3. International magnetic pulse compression workshop: (Proceedings)

    SciTech Connect (OSTI)

    Kirbie, H.C.; Newton, M.A.; Siemens, P.D.

    1991-04-01

    A few individuals have tried to broaden the understanding of specific and salient pulsed-power topics. One such attempt is this documentation of a workshop on magnetic switching as it applies primarily to pulse compression (power transformation), affording a truly international perspective by its participants under the initiative and leadership of Hugh Kirbie and Mark Newton of the Lawrence Livermore National Laboratory (LLNL) and supported by other interested organizations. During the course of the Workshop at Granlibakken, a great deal of information was amassed and a keen insight into both the problems and opportunities as to the use of this switching approach was developed. The segmented workshop format proved ideal for identifying key aspects affecting optimum performance in a variety of applications. Individual groups of experts addressed network and system modeling, magnetic materials, power conditioning, core cooling and dielectrics, and finally circuits and application. At the end, they came together to consolidate their input and formulate the workshop's conclusions, identifying roadblocks or suggesting research projects, particularly as they apply to magnetic switching's trump card--its high-average-power-handling capability (at least on a burst-mode basis). The workshop was especially productive both in the quality and quantity of information transfer in an environment conducive to a free and open exchange of ideas. We will not delve into the organization proper of this meeting, rather we wish to commend to the interested reader this volume, which provides the definitive and most up-to-date compilation on the subject of magnetic pulse compression from underlying principles to current state of the art as well as the prognosis for the future of magnetic pulse compression as a consensus of the workshop's organizers and participants.

  4. Laser beam pulse formatting method

    DOE Patents [OSTI]

    Daly, T.P.; Moses, E.I.; Patterson, R.W.; Sawicki, R.H.

    1994-08-09

    A method for formatting a laser beam pulse using one or more delay loops is disclosed. The delay loops have a partially reflective beam splitter and a plurality of highly reflective mirrors arranged such that the laser beam pulse enters into the delay loop through the beam splitter and circulates therein along a delay loop length defined by the mirrors. As the laser beam pulse circulates within the delay loop a portion thereof is emitted upon each completed circuit when the laser beam pulse strikes the beam splitter. The laser beam pulse is thereby formatted into a plurality of sub-pulses. The delay loops are used in combination to produce complex waveforms by combining the sub-pulses using additive waveform synthesis. 8 figs.

  5. Compression of picosecond pulses from a solid-state laser using self-phase modulation in graded-index fibers

    SciTech Connect (OSTI)

    Damm, T.; Kaschke, M.; Noack, F.; Wilhelmi, B.

    1985-04-01

    We report the compression by a factor of 7 of 2-..mu..J pulses of 5-psec duration from a mode-locked Nd:phosphate glass laser. The pulses were chirped and their spectrum broadened while traveling through a graded-index core fiber. After amplification to 500 ..mu..J, they were finally compressed by traveling through a dispersive delay line, and 0.7-psec pulse widths were achieved.

  6. Mode-locked terahertz quantum cascade laser by direct phase synchronization

    SciTech Connect (OSTI)

    Maussang, K.; Maysonnave, J.; Jukam, N.; Freeman, J. R.; Cavalié, P.; Dhillon, S. S.; Tignon, J.; Khanna, S. P.; Linfield, E. H.; Davies, A. G.; Beere, H. E.; Ritchie, D. A.

    2013-12-04

    Mode-locking of a terahertz quantum cascade laser is achieved using multimode injection seeding. Contrary to standard methods that rely on gain modulation, here a fixed phase relationship is directly imprinted to the laser modes. In this work, we demonstrate the generation of 9 ps phase mode-locked pulses around 2.75 THz. A direct measurement of the emitted field phase shows that it results from the phase of the initial injection.

  7. High-speed pulse-shape generator, pulse multiplexer

    DOE Patents [OSTI]

    Burkhart, Scott C. (Livermore, CA)

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  8. Mode Initialization for On-line Estimation of Power System Electromechanical Modes

    SciTech Connect (OSTI)

    Zhou, Ning; Trudnowski, Daniel; Pierre, John W.

    2009-03-18

    Measurement-based mode estimation methods are utilized to estimate electromechanical modes of a power system using phasor measurement units (PMU) data. These methods need to extract a certain amount of information before they can give useable mode estimation. Traditionally, the information is gathered solely from measurement data. Priori mode information from other resources (e.g. model eigenvalue analysis, engineering knowledge) are not fully utilized. For real time application, this means that mode estimation takes time to converge. By adding a mode regularization term in the objective function, this paper proposes a mode initialization method to include priori mode information in a regularized robust recursive least squares (R3LS) algorithm for on-line mode estimation. The proposed method is tested using a simple model, a 17 machine model and is shown to be able to shorten the convergence period of the R3LS algorithm. The proposed method is also applied on the measurement data recorded right before a major power outage in the western North American Grid on August 10th 1996 to show its potential applica-tion in detecting an approaching small signal stability problem.

  9. Exploring Ramsey-coherent population trapping atomic clock realized with pulsed microwave modulated laser

    SciTech Connect (OSTI)

    Yang, Jing; Yun, Peter [Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Tian, Yuan; Tan, Bozhong [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Gu, Sihong, E-mail: shgu@wipm.ac.cn [Key Laboratory of Atomic Frequency Standards, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-03-07

    A scheme for a Ramsey-coherent population trapping (CPT) atomic clock that eliminates the acousto-optic modulator (AOM) is proposed and experimentally studied. Driven by a periodically microwave modulated current, the vertical-cavity surface-emitting laser emits a continuous beam that switches between monochromatic and multichromatic modes. Ramsey-CPT interference has been studied with this mode-switching beam. In eliminating the AOM, which is used to generate pulsed laser in conventional Ramsey-CPT atomic clock, the physics package of the proposed scheme is virtually the same as that of a conventional compact CPT atomic clock, although the resource budget for the electronics will slightly increase as a microwave switch should be added. By evaluating and comparing experimentally recorded signals from the two Ramsey-CPT schemes, the short-term frequency stability of the proposed scheme was found to be 46% better than the scheme with AOM. The experimental results suggest that the implementation of a compact Ramsey-CPT atomic clock promises better frequency stability.

  10. Coiled transmission line pulse generators

    DOE Patents [OSTI]

    McDonald, Kenneth Fox (Columbia, MO)

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  11. Possible high power limitations from RF pulsed heating

    SciTech Connect (OSTI)

    Pritzkau, D.P.; Bowden, G.B.; Menegat, A.; Siemann, R.H. [Stanford Linear Accelerator Center, Stanford University, California 94309 (United States)

    1999-05-01

    One of the possible limitations to achieving high power in RF structures is damage to metal surfaces due to RF pulsed heating. Such damage may lead to degradation of RF performance. An experiment to study RF pulsed heating on copper has been developed at SLAC. The experiment consists of operating two pillbox cavities in the TE{sub 011} mode using a 50 MW X-Band klystron. The estimated temperature rise of the surface of copper is 350&hthinsp;{degree}C for a power input of 20 MW to each cavity with a pulse length of 1.5 {mu}s. Preliminary results from an experiment performed earlier are presented. A revised design for continued experiments is also presented along with relevant theory and calculations. {copyright} {ital 1999 American Institute of Physics.}

  12. Diffraction mode terahertz tomography

    DOE Patents [OSTI]

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

    2006-10-31

    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.

  13. Green Light Pulse Oximeter

    DOE Patents [OSTI]

    Scharf, John Edward (Oldsmar, FL)

    1998-11-03

    A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

  14. Short-Pulse Lasers

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopment Top Scientific Impact SinceServiceShipping ToShort-Pulse

  15. An optical parametric chirped-pulse amplifier for seeding high repetition rate free-electron lasers

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

    Höppner, H.; Hage, A.; Tanikawa, T.; Schulz, M.; Riedel, R.; Teubner, U.; Prandolini, M. J.; Faatz, B.; Tavella, F.

    2015-05-15

    High repetition rate free-electron lasers (FEL), producing highly intense extreme ultraviolet and x-ray pulses, require new high power tunable femtosecond lasers for FEL seeding and FEL pump-probe experiments. A tunable, 112 W (burst mode) optical parametric chirped-pulse amplifier (OPCPA) is demonstrated with center frequencies ranging from 720–900 nm, pulse energies up to 1.12 mJ and a pulse duration of 30 fs at a repetition rate of 100 kHz. Since the power scalability of this OPCPA is limited by the OPCPA-pump amplifier, we also demonstrate a 6.7–13.7 kW (burst mode) thin-disk OPCPA-pump amplifier, increasing the possible OPCPA output power to manymore »hundreds of watts. Furthermore, third and fourth harmonic generation experiments are performed and the results are used to simulate a seeded FEL with high-gain harmonic generation.« less

  16. The electron geodesic acoustic mode

    SciTech Connect (OSTI)

    Chakrabarti, N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700 064 (India); Guzdar, P. N. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Kaw, P. K. [Institute for Plasma Research Bhat, Gandhinagar 382428 (India)

    2012-09-15

    In this report, a novel new mode, named the electron geodesic acoustic mode, is presented. This mode can occur in toroidal plasmas like the conventional geodesic acoustic mode (GAM). The frequency of this new mode is much larger than that of the conventional GAM by a factor equal to the square root of the ion to electron mass ratio.

  17. Long Pulse EBW Start-up Experiments in MAST

    E-Print Network [OSTI]

    Shevchenko, V F; Caughman, J B; Diem, S; Mailloux, J; Brien, M R O; Peng, M; Saveliev, A N; Takase, Y; Tanaka, H; Taylor, G

    2015-01-01

    The non-solenoid start-up technique reported here relies on a double mode conversion for electron Bernstein wave (EBW) excitation. It consists of the mode conversion of the ordinary mode, entering the plasma from the low field side of the tokamak, into the extraordinary (X) mode at a mirror-polarizer located at the high field side. The X mode propagates back to the plasma, passes through electron cyclotron resonance and experiences a subsequent X to EBW mode conversion near the upper hybrid resonance. Finally the excited EBW mode is totally absorbed at the Doppler shifted electron cyclotron resonance. The absorption of EBW remains high even in cold rarefied plasmas. Furthermore, EBW can generate significant plasma current giving the prospect of a fully solenoid-free plasma start-up. First experiments using this scheme were carried out on MAST [V. Shevchenko et al, Nuclear Fusion 50, 022004 (2010)]. Plasma currents up to 33 kA have been achieved using 28 GHz 100kW 90ms RF pulses. Recently experimental results ...

  18. Multiple current peaks in room-temperature atmospheric pressure homogenous dielectric barrier discharge plasma excited by high-voltage tunable nanosecond pulse in air

    SciTech Connect (OSTI)

    Yang, De-Zheng; Wang, Wen-Chun; Zhang, Shuai; Tang, Kai; Liu, Zhi-jie; Wang, Sen

    2013-05-13

    Room temperature homogenous dielectric barrier discharge plasma with high instantaneous energy efficiency is acquired by using nanosecond pulse voltage with 20-200 ns tunable pulse width. Increasing the voltage pulse width can lead to the generation of regular and stable multiple current peaks in each discharge sequence. When the voltage pulse width is 200 ns, more than 5 organized current peaks can be observed under 26 kV peak voltage. Investigation also shows that the organized multiple current peaks only appear in homogenous discharge mode. When the discharge is filament mode, organized multiple current peaks are replaced by chaotic filament current peaks.

  19. Pulsed atmospheric fluidized bed combustion

    SciTech Connect (OSTI)

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  20. Bipolar pulse forming line

    DOE Patents [OSTI]

    Rhodes, Mark A. (Pleasanton, CA)

    2008-10-21

    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  1. Compensated pulsed alternator

    DOE Patents [OSTI]

    Weldon, William F. (Austin, TX); Driga, Mircea D. (Austin, TX); Woodson, Herbert H. (Austin, TX)

    1980-01-01

    This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

  2. Switching power pulse system

    DOE Patents [OSTI]

    Aaland, K.

    1983-08-09

    A switching system for delivering pulses of power from a source to a load using a storage capacitor charged through a rectifier, and maintained charged to a reference voltage level by a transistor switch and voltage comparator. A thyristor is triggered to discharge the storage capacitor through a saturable reactor and fractional turn saturable transformer having a secondary to primary turn ratio N of n:l/n = n[sup 2]. The saturable reactor functions as a soaker'' while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor charges, and then switches to a low impedance state to dump the charge of the storage capacitor into the load through the coupling capacitor. The transformer is comprised of a multilayer core having two secondary windings tightly wound and connected in parallel to add their output voltage and reduce output inductance, and a number of single turn windings connected in parallel at nodes for the primary winding, each single turn winding linking a different one of the layers of the multilayer core. The load may be comprised of a resistive beampipe for a linear particle accelerator and capacitance of a pulse forming network. To hold off discharge of the capacitance until it is fully charged, a saturable core is provided around the resistive beampipe to isolate the beampipe from the capacitance until it is fully charged. 5 figs.

  3. Fast pulse nonthermal plasma reactor

    DOE Patents [OSTI]

    Rosocha, Louis A.

    2005-06-14

    A fast pulsed nonthermal plasma reactor includes a discharge cell and a charging assembly electrically connected thereto. The charging assembly provides plural high voltage pulses to the discharge cell. Each pulse has a rise time between one and ten nanoseconds and a duration of three to twenty nanoseconds. The pulses create nonthermal plasma discharge within the discharge cell. Accordingly, the nonthermal plasma discharge can be used to remove pollutants from gases or break the gases into smaller molecules so that they can be more efficiently combusted.

  4. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  5. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  6. High harmonic attosecond pulse train amplification in a free electron laser

    SciTech Connect (OSTI)

    McNeil, B.W.; Sheehy, B.; Thompson, N.R.; Dunning, D.J.

    2011-03-04

    It is shown using three-dimensional simulations that the temporal structure of an attosecond pulse train, such as that generated via high harmonic generation in noble gases, may be retained in a free electron laser amplifier through to saturation using a mode-locked optical klystron configuration. At wavelengths of {approx}12 nm, a train of attosecond pulses of widths {approx}300 as with peak powers in excess of 1 GW are predicted.

  7. Classical and Quantum Dynamics of Free Electromagnetic Laser Pulses

    E-Print Network [OSTI]

    Goto, S; Walton, T J

    2015-01-01

    We discuss the use of a class of exact finite energy solutions to the vacuum source free Maxwell equations as models for multi- and single cycle laser pulses in classical interaction with relativistic charged point particles. These solutions are classified in terms of their chiral content and their influence on particular charge configurations in space. The results of such classical interactions motivate a particular quantum description of a freely propagating laser pulse in terms of an effective quantum Hamiltonian. The classical chiral states that evolve according to the classical vacuum Maxwell equations are now replaced by quantized bi-qutrit elements satisfying the Schrodinger equation. This description may offer a means to control and manipulate qu-trit states encoded into such laser pulses.

  8. Classical and Quantum Dynamics of Free Electromagnetic Laser Pulses

    E-Print Network [OSTI]

    S. Goto; R. W. Tucker; T. J. Walton

    2015-02-09

    We discuss the use of a class of exact finite energy solutions to the vacuum source free Maxwell equations as models for multi- and single cycle laser pulses in classical interaction with relativistic charged point particles. These solutions are classified in terms of their chiral content and their influence on particular charge configurations in space. The results of such classical interactions motivate a particular quantum description of a freely propagating laser pulse in terms of an effective quantum Hamiltonian. The classical chiral states that evolve according to the classical vacuum Maxwell equations are now replaced by quantized bi-qutrit elements satisfying the Schrodinger equation. This description may offer a means to control and manipulate qu-trit states encoded into such laser pulses.

  9. 2258 IEEE TRANSACTIONS ON MAGNETICS, VOL. 33, NO. 3, MAY 1997 Pulsed Eddy-Current Response

    E-Print Network [OSTI]

    Bowler, John R.

    2258 IEEE TRANSACTIONS ON MAGNETICS, VOL. 33, NO. 3, MAY 1997 Pulsed Eddy-Current Response to a Conducting Half-Space John Bowler, Member, IEEE, and Marcus Johnson Abstract-- Eddy-current nondestructive agreement between theory and experiment. Index Terms--Eddy current, half-space, pulsed, transient. I

  10. Modes of perceiving and imagining 

    E-Print Network [OSTI]

    Nudds, Matthew

    2000-01-01

    We enjoy modes of sensory imagining corresponding to our five modes of perception - seeing, touching, hearing, smelling and tasting. An account of what constitutes these different modes of perseption needs also to explain ...

  11. SLIM, Short-pulse Technology for High Gradient Induction Accelerators

    SciTech Connect (OSTI)

    Arntz, Floyd; Kardo-Sysoev, A.; Krasnykh, A.; /SLAC

    2008-12-16

    A novel short-pulse concept (SLIM) suited to a new generation of a high gradient induction particle accelerators is described herein. It applies advanced solid state semiconductor technology and modern microfabrication techniques to a coreless induction method of charged particle acceleration first proven on a macro scale in the 1960's. Because this approach avoids use of magnetic materials there is the prospect of such an accelerator working efficiently with accelerating pulses in the nanosecond range and, potentially, at megahertz pulse rates. The principal accelerator section is envisioned as a stack of coreless induction cells, the only active element within each being a single, extremely fast (subnanosecond) solid state opening switch: a Drift Step Recovery Diode (DSRD). Each coreless induction cell incorporates an electromagnetic pulse compressor in which inductive energy developed within a transmission-line feed structure over a period of tens of nanoseconds is diverted to the acceleration of the passing charge packet for a few nanoseconds by the abrupt opening of the DSRD switch. The duration of this accelerating output pulse--typically two-to-four nanoseconds--is precisely determined by a microfabricated pulse forming line connected to the cell. Because the accelerating pulse is only nanoseconds in duration, longitudinal accelerating gradients approaching 100 MeV per meter are believed to be achievable without inciting breakdown. Further benefits of this approach are that, (1) only a low voltage power supply is required to produce the high accelerating gradient, and, (2) since the DSRD switch is normally closed, voltage stress is limited to a few nanoseconds per period, hence the susceptibility to hostile environment conditions such as ionizing radiation, mismatch (e.g. in medical applications the peak beam current may be low), strong electromagnetic noise levels, etc is expected to be minimal. Finally, we observe the SLIM concept is not limited to linac applications; for instance, it could be employed to both accelerate the beam and to stabilize the superbunch mode of operation in circular track machines.

  12. Accelerator-mode-based technique for studying quantum chaos

    SciTech Connect (OSTI)

    D'Arcy, M.B.; Godun, R.M.; Cassettari, D. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Summy, G.S. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078-3072 (United States)

    2003-02-01

    We experimentally demonstrate a method for selecting small regions of phase space for kicked rotor quantum chaos experiments with cold atoms. Our technique uses quantum accelerator modes to selectively accelerate atomic wave packets with localized spatial and momentum distributions. The potential used to create the accelerator mode and subsequently realize the kicked rotor system is formed by a set of off-resonant standing-wave light pulses. We also propose a method for testing whether a selected region of phase space exhibits chaotic or regular behavior using a Ramsey type separated field experiment.

  13. Pulsed depressed collector

    DOE Patents [OSTI]

    Kemp, Mark A

    2015-11-03

    A high power RF device has an electron beam cavity, a modulator, and a circuit for feed-forward energy recovery from a multi-stage depressed collector to the modulator. The electron beam cavity include a cathode, an anode, and the multi-stage depressed collector, and the modulator is configured to provide pulses to the cathode. Voltages of the electrode stages of the multi-stage depressed collector are allowed to float as determined by fixed impedances seen by the electrode stages. The energy recovery circuit includes a storage capacitor that dynamically biases potentials of the electrode stages of the multi-stage depressed collector and provides recovered energy from the electrode stages of the multi-stage depressed collector to the modulator. The circuit may also include a step-down transformer, where the electrode stages of the multi-stage depressed collector are electrically connected to separate taps on the step-down transformer.

  14. Influences of impedance matching network on pulse-modulated radio frequency atmospheric pressure glow discharges

    SciTech Connect (OSTI)

    Huo, W. G. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Xu, K.; Sun, B.; Ding, Z. F. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

    2012-08-15

    Pulse-modulated RF atmospheric pressure glow discharges (APDGs) were investigated in recent years to reduce the thermal accumulation and extend the operation region of the stable alpha glow mode. Different pulse-modulated voltage and current waveforms were acquired in previous experiments, but no attention was paid to the interpretation. We investigated this issue and associated phenomenon via positive and negative feedback effects derived from varying the series capacitor in the inversely L-shaped matching network used in our pulse-modulated RF APGD source. The evolutions of pulse-modulated RF waveforms were found to be associated with the feedback region and the pulsed plasma absorbed RF power. In the positive feedback region, pulse-modulated RF APGDs are relatively stable. In the negative feedback region, wide spikes as well as undershoots occur in RF voltage and current waveforms and the plasma absorbed RF power. In case of a high RF power discharge with a low modulation frequency, the pulse-modulated RF APGD is extinguished and re-ignited due to the enhanced undershoot during the initial pulse phase. The pulse-modulated RF APGD can transit from positive to negative feedback region in a range of series capacitance. Experimental results are discussed by the aid of equivalent circuit, negative and positive feedback effects.

  15. Pulsed atmospheric fluidized bed combustion

    SciTech Connect (OSTI)

    Not Available

    1992-08-01

    The general specifications for a Pulsed Atmospheric Fluidized Bed Combustor Design Report (PAFBC) plant are presented. The design tasks for the PAFBC are described in the following areas: Coal/Limestone preparation and feed system; pulse combustor; fluidized bed; boiler parts; and ash handling system.

  16. Switching power pulse system

    DOE Patents [OSTI]

    Aaland, Kristian (Livermore, CA)

    1983-01-01

    A switching system for delivering pulses of power from a source (10) to a load (20) using a storage capacitor (C3) charged through a rectifier (D1, D2), and maintained charged to a reference voltage level by a transistor switch (Q1) and voltage comparator (12). A thyristor (22) is triggered to discharge the storage capacitor through a saturable reactor (18) and fractional turn saturable transformer (16) having a secondary to primary turn ratio N of n:l/n=n.sup.2. The saturable reactor (18) functions as a "soaker" while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor (C4) charges, and then switches to a low impedance state to dump the charge of the storage capacitor (C3) into the load through the coupling capacitor (C4). The transformer is comprised of a multilayer core (26) having two secondary windings (28, 30) tightly wound and connected in parallel to add their output voltage and reduce output inductance, and a number of single turn windings connected in parallel at nodes (32, 34) for the primary winding, each single turn winding linking a different one of the layers of the multilayer core. The load may be comprised of a resistive beampipe (40) for a linear particle accelerator and capacitance of a pulse forming network (42). To hold off discharge of the capacitance until it is fully charged, a saturable core (44) is provided around the resistive beampipe (40) to isolate the beampipe from the capacitance (42) until it is fully charged.

  17. Two stroke homogenous charge compression ignition engine with pulsed air supplier

    DOE Patents [OSTI]

    Clarke, John M. (Chillicothe, IL)

    2003-08-05

    A two stroke homogenous charge compression ignition engine includes a volume pulsed air supplier, such as a piston driven pump, for efficient scavenging. The usage of a homogenous charge tends to decrease emissions. The use of a volume pulsed air supplier in conjunction with conventional poppet type intake and exhaust valves results in a relatively efficient scavenging mode for the engine. The engine preferably includes features that permit valving event timing, air pulse event timing and injection event timing to be varied relative to engine crankshaft angle. The principle use of the invention lies in improving diesel engines.

  18. A high voltage pulse power supply for metal plasma immersion ion implantation and deposition

    SciTech Connect (OSTI)

    Salvadori, M. C.; Teixeira, F. S.; Araujo, W. W. R.; Sgubin, L. G.; Sochugov, N. S.; Spirin, R. E.; Brown, I. G.

    2010-12-15

    We describe the design and implementation of a high voltage pulse power supply (pulser) that supports the operation of a repetitively pulsed filtered vacuum arc plasma deposition facility in plasma immersion ion implantation and deposition (Mepiiid) mode. Negative pulses (micropulses) of up to 20 kV in magnitude and 20 A peak current are provided in gated pulse packets (macropulses) over a broad range of possible pulse width and duty cycle. Application of the system consisting of filtered vacuum arc and high voltage pulser is demonstrated by forming diamond-like carbon (DLC) thin films with and without substrate bias provided by the pulser. Significantly enhanced film/substrate adhesion is observed when the pulser is used to induce interface mixing between the DLC film and the underlying Si substrate.

  19. Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

    SciTech Connect (OSTI)

    Liu, Yun [ORNL; Huang, Chunning [ORNL; Aleksandrov, Alexander V [ORNL

    2013-01-01

    We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstration of particle beam profile diagnostics using fiber optic laser pulse transmission line.

  20. Plasmon modes of metallic nanowires including quantum nonlocal effects

    SciTech Connect (OSTI)

    Moradi, Afshin

    2015-03-15

    The properties of electrostatic surface and bulk plasmon modes of cylindrical metallic nanowires are investigated, using the quantum hydrodynamic theory of plasmon excitation which allows an analytical study of quantum tunneling effects through the Bohm potential term. New dispersion relations are obtained for each type of mode and their differences with previous treatments based on the standard hydrodynamic model are analyzed in detail. Numerical results show by considering the quantum effects, as the value of wave number increases, the surface modes are slightly red-shifted first and then blue-shifted while the bulk modes are blue-shifted.

  1. Theory of Pulsed Four-Wave-Mixing in One-dimensional Silicon Photonic Crystal Slab Waveguides

    E-Print Network [OSTI]

    Lavdas, Spyros

    2015-01-01

    We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general set-up of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulae for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveg...

  2. The Pulse Line Ion Accelerator Concept

    E-Print Network [OSTI]

    Briggs, Richard J.

    2006-01-01

    field model of the pulse- line accelerator; relationship to3, 2006 LBNL-59492 The pulse line ion accelerator conceptCalifornia, 94507 The Pulse Line Ion Accelerator concept was

  3. Parametric study of broadband terahertz radiation generation based on interaction of two-color ultra-short laser pulses

    SciTech Connect (OSTI)

    Moradi, S.; Ganjovi, A.; Shojaei, F.; Saeed, M.

    2015-04-15

    In this work, using a two-dimensional kinetic model based on particle in cell-Monte Carlo collision simulation method, the influence of different parameters on the broadband intense Terahertz (THz) radiation generation via application of two-color laser fields, i.e., the fundamental and second harmonic modes, is studied. These two modes are focused into the molecular oxygen (O{sub 2}) with uniform density background gaseous media and the plasma channels are created. Thus, a broadband THz pulse that is around the plasma frequency is emitted from the formed plasma channel and co-propagates with the laser pulse. For different laser pulse shapes, the THz electric field and its spectrum are both calculated. The effects of laser pulse and medium parameters, i.e., positive and negative chirp pulse, number of laser cycles in the pulse, laser pulse shape, background gas pressure, and exerted DC electric field on THz spectrum are verified. Application of a negatively chirped femtosecond (40 fs) laser pulse results in four times enhancement of the THz pulse energy (2 times in THz electric field). The emission of THz radiation is mostly observed in the forward direction.

  4. Cluster Compatibility Mode

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAuditsCluster Compatibility Mode Cluster Compatibility Mode Edison compute

  5. Cluster Compatibility Mode

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAuditsCluster Compatibility Mode Cluster Compatibility Mode Edison

  6. High power pulsed magnicon at 34-GHz

    SciTech Connect (OSTI)

    Nezhevenko, O.A.; Yakovlev, V.P.; Ganguly, A.K.; Hirshfield, J.L. [Omega-P Inc., 202008 Yale Station, New Haven, Connecticut 06520 (United States)

    1999-05-01

    A high efficiency, high power magnicon amplifier at 34.272 GHz has been designed as a radiation source to drive multi-TeV electron-positron linear colliders. Simulations show peak output power of 45 MW in a 1.5 microsecond wide pulse with an efficiency of 45{percent} and gain of 55 dB. The repetition rate is 10 Hz. The amplifier is a frequency tripler, or third harmonic amplifier, in that the output frequency of 34.272 GHz is three times the input drive frequency of 11.424 GHz. Thus the rotating TM{sub 110} modes in the drive cavity, 3 gain cavities and double decoupled penultimate cavities are resonant near 11.424 GHz; and the rotating TM{sub 310} mode in the output cavity is resonant at 34.272 GHz. A 500 kV, 200 A high area compression electron gun will provide a low emittance electron beam with a diameter of about 0.8 mm. A superconducting solenoid magnet will provide a magnetic field of 13 kG in the deflection system and 22 kG in the output cavity. A collector for the spent beam has also been designed. Detailed simulation results for the operation of the entire magnicon amplifier (gun, magnetic system, rf system and collector) will be given. {copyright} {ital 1999 American Institute of Physics.}

  7. Dielectric liquid pulsed-power switch

    DOE Patents [OSTI]

    Christophorou, Loucas G. (Oak Ridge, TN); Faidas, Homer (Knoxville, TN)

    1990-01-01

    This disclosure identifies dielectric liquids for use as opening and closing switching media in pulsed power technology, and describes a dielectric-liquid-pulsed-power switch empolying flashlamps.

  8. Generation of 15-nJ pulses from a highly efficient, low-cost multipass-cavity Cr[superscript 3+]:LiCAF laser

    E-Print Network [OSTI]

    Demirbas, Umit

    We describe the generation of enhanced pulse energies using a multipass-cavity (MPC) Cr[superscript3] +:LiCAF laser, pumped by inexpensive, single spatial mode laser diodes. A semiconductor saturable absorber was used for ...

  9. Pulsed atmospheric fluidized bed combustion

    SciTech Connect (OSTI)

    Not Available

    1993-01-01

    The Design and Engineering of most components in the Pulsed Atmospheric Fluidized Bed System was completed prior to September 1992. The components remaining to be designed at that time were: Aerovalves for the Pulse Combustor; Gas and coal injectors for the Pulse Combustor; Lines for PC tailpipes; Air plenum and inlet silencer; Refractory lined hot gas duct connecting outlet hot cyclone to boiler; Structure and platforms, and ladders around PAFBC vessel access and major equipment. Design work is currently in progress on all of the above components. Items 1, 2, 3 and 4 are 50% completed, and items 5 6 are 75% complete.

  10. Pulsed ion beam source

    DOE Patents [OSTI]

    Greenly, J.B.

    1997-08-12

    An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

  11. Hyper dispersion pulse compressor for chirped pulse amplification systems

    DOE Patents [OSTI]

    Barty, Christopher P. J. (Hayward, CA)

    2011-11-29

    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  12. 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)

    1994-01-01

    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.

  13. Excitation of the Morse oscillator by an ultrashort chirped pulse

    SciTech Connect (OSTI)

    Astapenko, V. A., E-mail: astval@mail.ru; Romadanovskii, M. S. [Moscow Institute of Physics and Technology (Russian Federation)

    2010-03-15

    The excitation of the classic Morse oscillator by an ultrashort electromagnetic pulse with a linear frequency chirp is studied theoretically. Formulas are derived for the oscillation amplitude and the radiation power averaged over a period as functions of the excitation energy for free oscillations of the Morse oscillator. Analytical expressions for describing the oscillator motion after the end of the pulse are obtained in the harmonic limit. In the general case of arbitrary parameters of the problem, the specific features of an excited Morse oscillator are analyzed numerically. Prominence is given to the effect of chirp on the excitation energy. The consideration is performed in terms of dimensionless variables, which makes it possible to apply the results obtained to a wide range of molecular systems and exciting-pulse parameters.

  14. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOE Patents [OSTI]

    Konrad, C.E.; Boothe, R.W.

    1996-01-23

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. 6 figs.

  15. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOE Patents [OSTI]

    Konrad, Charles E. (Roanoke, VA); Boothe, Richard W. (Roanoke, VA)

    1994-01-01

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

  16. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOE Patents [OSTI]

    Konrad, Charles E. (Roanoke, VA); Boothe, Richard W. (Roanoke, VA)

    1996-01-01

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

  17. Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive

    DOE Patents [OSTI]

    Konrad, C.E.; Boothe, R.W.

    1994-02-15

    A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. 6 figures.

  18. Beam Pulse Structure and Targets Roger Bennett

    E-Print Network [OSTI]

    McDonald, Kirk

    Beam Pulse Structure and Targets Roger Bennett Rutherford Appleton Laboratory, Chilton, Didcot jets Thermal shock is not a problem - provided the pulse is short enough. #12;Shock, Pulse Length that there is permanent distortion or failure - shock. Short high intensity beam pulses will give rise to shock

  19. Harold G. Kirk High Field Pulsed Solenoid

    E-Print Network [OSTI]

    McDonald, Kirk

    Harold G. Kirk High Field Pulsed Solenoid 70o K Operation 15 T with 4.5 MW Pulsed Power 15 cm warm bore 1 m long beam pipe Peter Titus, MIT #12;Harold G. Kirk MARS Dose Calculation Pulsed Solenoid Iron Copper Hg Jet #12;Harold G. Kirk Residual Contact Dose Rate Assume: 200 pulses 16 x 1012 protons

  20. Distributedfeedback pulse generator based on nonlinearfibre grating

    E-Print Network [OSTI]

    Sipe,J. E.

    Distributedfeedback pulse generator based on nonlinearfibre grating B.J. Eggleton, C.M. de Sterke pulse generator or reshaper with applications in all-optical communications. Introduction: Fibre. This could form the basis of a pulse reshaper or pulse generator device with applications in future all

  1. Tailoring the laser pulse shape to improve the quality of the self-injected electron beam in laser wakefield acceleration

    SciTech Connect (OSTI)

    Upadhyay, Ajay K.; Samant, Sushil A.; Krishnagopal, S.

    2013-01-15

    In laser wakefield acceleration, tailoring the shape of the laser pulse is one way of influencing the laser-plasma interaction and, therefore, of improving the quality of the self-injected electron beam in the bubble regime. Using three-dimensional particle-in-cell simulations, the evolution dynamics of the laser pulse and the quality of the self-injected beam, for a Gaussian pulse, a positive skew pulse (i.e., one with sharp rise and slow fall), and a negative skew pulse (i.e., one with a slow rise and sharp fall) are studied. It is observed that with a negative skew laser pulse there is a substantial improvement in the emittance (by around a factor of two), and a modest improvement in the energy-spread, compared to Gaussian as well as positive skew pulses. However, the injected charge is less in the negative skew pulse compared to the other two. It is also found that there is an optimal propagation distance that gives the best beam quality; beyond this distance, though the energy increases, the beam quality deteriorates, but this deterioration is least for the negative skew pulse. Thus, the negative skew pulse gives an improvement in terms of beam quality (emittance and energy spread) over what one can get with a Gaussian or positive skew pulse. In part, this is because of the lesser injected charge, and the strong suppression of continuous injection for the negative skew pulse.

  2. Application of pulse combustion to solid and hazardous-waste incineration

    SciTech Connect (OSTI)

    Stewart, C.R.; Lemieux, P.M.; Zinn, B.T.

    1991-01-01

    The paper discusses the application of pulse combustion to solid and hazardous waste incineration. A rotary kiln incinerator simulator was retrofitted with a frequency-tunable pulse combustor to enhance the efficiency of combustion. The pulse combustor excites pulsations in the kiln and increases the completeness of combustion by promoting better mixing within the system. Tests were performed using toluene sorbed onto a ground corn cob sorbent and placed in cardboard containers. The burner was operated in a non-pulse mode as a baseline condition, and then in a pulse mode in which the frequency of the pulse combustor was adjusted to the natural frequency of the combustion chamber, creating resonant pulsations of large magnitude. The test was also performed using polyethylene tube bundles to simulate a solid waste and to investigate a surrogate which produces different puff characteristics. The addition of turbulence in the rotary kiln due to high amplitude acoustic pulsations has a strong tendency to reduce the amount of soot and/or semivolatile and non-volatile hydrocarbons. Mass emissions of soot were consistently reduced in all tests. Carbon monoxide increased during acoustic pulsations in the toluene tests. The paper also discusses unsatisfied oxygen demand and carbon penetration and how pulsations affect them.

  3. Constraining primordial vector mode from B-mode polarization

    SciTech Connect (OSTI)

    Saga, Shohei; Ichiki, Kiyotomo; Shiraishi, Maresuke E-mail: maresuke.shiraishi@pd.infn.it

    2014-10-01

    The B-mode polarization spectrum of the Cosmic Microwave Background (CMB) may be the smoking gun of not only the primordial tensor mode but also of the primordial vector mode. If there exist nonzero vector-mode metric perturbations in the early Universe, they are known to be supported by anisotropic stress fluctuations of free-streaming particles such as neutrinos, and to create characteristic signatures on both the CMB temperature, E-mode, and B-mode polarization anisotropies. We place constraints on the properties of the primordial vector mode characterized by the vector-to-scalar ratio r{sub v} and the spectral index n{sub v} of the vector-shear power spectrum, from the Planck and BICEP2 B-mode data. We find that, for scale-invariant initial spectra, the ?CDM model including the vector mode fits the data better than the model including the tensor mode. The difference in ?{sup 2} between the vector and tensor models is ??{sup 2} = 3.294, because, on large scales the vector mode generates smaller temperature fluctuations than the tensor mode, which is preferred for the data. In contrast, the tensor mode can fit the data set equally well if we allow a significantly blue-tilted spectrum. We find that the best-fitting tensor mode has a large blue tilt and leads to an indistinct reionization bump on larger angular scales. The slightly red-tilted vector mode supported by the current data set can also create O(10{sup -22})-Gauss magnetic fields at cosmological recombination. Our constraints should motivate research that considers models of the early Universe that involve the vector mode.

  4. Short pulse free electron laser amplifier

    DOE Patents [OSTI]

    Schlitt, Leland G. (Livermore, CA); Szoke, Abraham (Fremont, CA)

    1985-01-01

    Method and apparatus for amplification of a laser pulse in a free electron laser amplifier where the laser pulse duration may be a small fraction of the electron beam pulse duration used for amplification. An electron beam pulse is passed through a first wiggler magnet and a short laser pulse to be amplified is passed through the same wiggler so that only the energy of the last fraction, f, (f<1) of the electron beam pulse is consumed in amplifying the laser pulse. After suitable delay of the electron beam, the process is repeated in a second wiggler magnet, a third, . . . , where substantially the same fraction f of the remainder of the electron beam pulse is consumed in amplification of the given short laser pulse in each wiggler magnet region until the useful electron beam energy is substantially completely consumed by amplification of the laser pulse.

  5. A multifunctional optical correlator for picosecond UV laser pulse measurement

    SciTech Connect (OSTI)

    Abudureyimu, Reheman [ORNL; Wang, Yang [University of Alabama, Huntsville; Garcia, Frances [University of Tennessee, Knoxville (UTK); Long, Cary D [ORNL; Huang, Chunning [ORNL; Takeda, Yasuhiro [ORNL; Liu, Yun [ORNL

    2014-01-01

    A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parameter dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.

  6. Pulsed CO laser for isotope separation of uranium

    SciTech Connect (OSTI)

    Baranov, Igor Y.; Koptev, Andrey V. [Rocket-Space Technics Department, Baltic State Technical University, 1, 1st Krasnoarmeyskaya st.,St. Petersburg, 190005 (Russian Federation)

    2012-07-30

    This article proposes a technical solution for using a CO laser facility for the industrial separation of uranium used in the production of fuel for nuclear power plants, employing a method of laser isotope separation of uranium with condensation repression in a free jet. The laser operation with nanosecond pulse irradiation can provide an acceptable efficiency in the separating unit and a high efficiency of the laser with the wavelength of 5.3 {mu}m. In the present work we also introduce a calculation model and define the parameters of a mode-locked CO laser with a RF discharge in the supersonic stream. The average pulsed CO laser power of 3 kW is sufficient for efficient industrial isotope separation of uranium in one stage.

  7. Reducing pulse distortion in fast-light pulse propagation through an erbium-doped

    E-Print Network [OSTI]

    Boyd, Robert W.

    Reducing pulse distortion in fast-light pulse propagation through an erbium-doped fiber amplifier, 2007 (Doc. ID 78405); published March 19, 2007 When a pulse superposed on a cw background propagates through an erbium-doped fiber amplifier with a negative group velocity, either pulse broadening or pulse

  8. Q-switched and mode-locked Er{sup 3+}-doped fibre laser using a single-multi-single fibre filter and piezoelectric

    SciTech Connect (OSTI)

    Ji Wang; Yunjun Zhang; Aotuo Dong; Xiaoxin Xu; Youlun Ju; Baoquan Yao [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin, China, 150001 (China)

    2014-04-28

    The active Q-switched and passive mode-locked Er{sup 3+}-doped all-fibre laser is presented. The fibre laser centre wavelength is located at 1563 nm and determined by the homemade singlemulti- single (SMS) in-line fibre filter. The laser spectrum width is nearly 0.1 nm. The active Q-switched mechanism relies on the polarisation state control using a piezoelectric to press a segment of passive fibre on the circular cavity. The nonlinear polarisation rotation technology is used to realise the passive self-started modelocked operation. In the passive mode-locked regimes, the output average power is 2.1 mW, repetition frequency is 11.96 MHz, and single pulse energy is 0.18 nJ. With the 100-Hz Q-switched regimes running, the output average power is 1.5 mW. The total Q-switched pulse width is 15 ?s, and every Q-switched pulse is made up by several tens of mode-locked peak pulses. The calculated output pulse energy of the Q-switched fibre laser is about 15 ?J, and the energy of every mode-locked pulse is about 64–68 nJ during a Q-switched pulse taking into account the power fraction propagating between pulses. (lasers)

  9. Cryogenics for Pulsed Solenoid Magnet

    E-Print Network [OSTI]

    McDonald, Kirk

    a) Equipment i) 14 k gallon LH2 Dewar (140 psig) ii) 5.88 k gallon LN2 Dewar (65 psig) iii) PSM PSM ST Mode 1, 2 Outside Inside 21 September 6, 2002 ACT #12;LH2 HE PSM Mode 5 Outside Inside GHe BT design vacuum (inner/outer shell) and foam (ends, shell outer) insulation. 5). Structural detail of PSM

  10. R-mode astronomy

    E-Print Network [OSTI]

    Kokkotas, Kostas D

    2015-01-01

    Next generation gravitational wave detectors will start taking data in the near future. Here we discuss the chances to detect the continuous emission from r-mode oscillations in compact stars and study which properties of compact stars we can infer from such novel data. In particular we show that the combination of the gravitational wave data with electromagnetic multi-messenger observations could give us detailed insight into compact star properties, ranging from precise mass-radius measurements to the determination of the equation of state and the phase structure of dense matter.

  11. Thermalization of Green functions and quasinormal modes

    E-Print Network [OSTI]

    Justin R. David; Surbhi Khetrapal

    2015-05-12

    We develop a new method to study the thermalization of time dependent retarded Green function in conformal field theories holographically dual to thin shell AdS Vaidya space times. The method relies on using the information of all time derivatives of the Green function at the shell and then evolving it for later times. The time derivatives of the Green function at the shell is given in terms of a recursion formula. Using this method we obtain analytic results for short time thermalization of the Green function. We show that the late time behaviour of the Green function is determined by the first quasinormal mode. We then implement the method numerically. As applications of this method we study the thermalization of the retarded time dependent Green function corresponding to a minimally coupled scalar in the AdS3 and AdS5 thin Vaidya shells. We see that as expected the late time behaviour is determined by the first quasinormal mode. We apply the method to study the late time behaviour of the shear vector mode in AdS5 Vaidya shell. At small momentum the corresponding time dependent Green function is expected to relax to equilibrium by the shear hydrodynamic mode. Using this we obtain the universal ratio of the shear viscosity to entropy density from a time dependent process.

  12. Radial flow pulse jet mixer

    DOE Patents [OSTI]

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  13. Pulse combustor with controllable oscillations

    DOE Patents [OSTI]

    Richards, George A. (Morgantown, WV); Welter, Michael J. (Columbiana, OH); Morris, Gary J. (Morgantown, WV)

    1992-01-01

    A pulse combustor having thermally induced pulse combustion in a continuously flowing system is described. The pulse combustor is fitted with at lease one elongated ceramic body which significantly increases the heat transfer area in the combustion chamber of the combustor. The ceramic body or bodies possess sufficient mass and heat capacity to ignite the fuel-air charge once the ceramic body or bodies are heated by conventional spark plug initiated combustion so as to provide repetitive ignition and combustion of sequentially introduced fuel-air charges without the assistance of the spark plug and the rapid quenching of the flame after each ignition in a controlled manner so as to provide a selective control over the oscillation frequency and amplitude. Additional control over the heat transfer in the combustion chamber is provided by employing heat exchange mechanisms for selectively heating or cooling the elongated ceramic body or bodies and/or the walls of the combustion chamber.

  14. Pulsed atmospheric fluidized bed combustion

    SciTech Connect (OSTI)

    Not Available

    1992-10-01

    The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

  15. Pulse combustor with controllable oscillations

    SciTech Connect (OSTI)

    Richards, G.A.; Morris, G.J.; Welter, M.J.

    1991-12-31

    A pulse combustor having thermally induced pulse combustion in a continuously flowing system is described. The pulse combustor is fitted with at lease one elongated ceramic body which significantly increases the heat transfer area in the combustion chamber of the combustor. The ceramic body or bodies possess sufficient mass and heat capacity to ignite the fuel-air charge once the ceramic body or bodies are heated by conventional spark plug initiated combustion so as to provide repetitive ignition and combustion of sequentially introduced fuel-air charges without the assistance of the spark plug and the rapid quenching of the flame after each ignition in a controlled manner so as to provide a selective control over the oscillation frequency and amplitude. Additional control over the heat transfer in the combustion chamber is provided by employing heat exchange mechanisms for selectively heating or cooling the elongated ceramic body or bodies and/or the walls of the combustion chamber.

  16. Plasma dynamics in a discharge produced by a pulsed dual frequency inductively coupled plasma source

    SciTech Connect (OSTI)

    Mishra, Anurag; Lee, Sehan [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Yeom, Geun Y., E-mail: gyyeom@skku.edu [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, South Korea and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2014-11-01

    Using a Langmuir probe, time resolved measurements of plasma parameters were carried out in a discharge produced by a pulsed dual frequency inductively coupled plasma source. The discharge was sustained in an argon gas environment at a pressure of 10 mTorr. The low frequency (P{sub 2} {sub MHz}) was pulsed at 1 kHz and a duty ratio of 50%, while high frequency (P{sub 13.56} {sub MHz}) was maintained in the CW mode. All measurements were carried out at the center of the discharge and 20?mm above the substrate. The results show that, at a particular condition (P{sub 2} {sub MHz}?=?200 W and P{sub 13.56} {sub MHz?}=?600 W), plasma density increases with time and stabilizes at up to ?200 ?s after the initiation of P{sub 2} {sub MHz} pulse at a plasma density of (2?×?10{sup 17} m{sup ?3}) for the remaining duration of pulse “on.” This stabilization time for plasma density increases with increasing P{sub 2} {sub MHz} and becomes ?300 ?s when P{sub 2} {sub MHz} is 600 W; however, the growth rate of plasma density is almost independent of P{sub 2} {sub MHz}. Interestingly, the plasma density sharply increases as the pulse is switched off and reaches a peak value in ?10 ?s, then decreases for the remaining pulse “off-time.” This phenomenon is thought to be due to the sheath modulation during the transition from “pulse on” to “pulse off” and partly due to RF noise during the transition period. The magnitude of peak plasma density in off time increases with increasing P{sub 2} {sub MHz}. The plasma potential and electron temperature decrease as the pulse develops and shows similar behavior to that of the plasma density when the pulse is switched off.

  17. Simulation of Double-Pulse Laser Ablation

    SciTech Connect (OSTI)

    Povarnitsyn, Mikhail E.; Khishchenko, Konstantin V.; Levashov, Pavel R. [Joint Institute for High Temperatures of RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Itina, Tatian E. [Laboratoire Hubert Curien, UMR CNRS 5516, 18 rue Benoit Lauras, Bat. F, 42000, St-Etienne (France)

    2010-10-08

    We investigate the physical reasons of a strange decrease in the ablation depth observed in femtosecond double-pulse experiments with increasing delay between the pulses. Two ultrashort pulses of the same energy produce the crater which is less than that created by a single pulse. Hydrodynamic simulation shows that the ablation mechanism is suppressed when the delay between the pulses exceeds the electron-ion relaxation time. In this case, the interaction of the second laser pulse with the expanding target material leads to the formation of the second shock wave suppressing the rarefaction wave created by the first pulse. The modeling of the double-pulse ablation for different delays between pulses confirms this explanation.

  18. 714 IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 12, NO. 6, JUNE 2000 Skew and Jitter Removal Using Short Optical Pulses

    E-Print Network [OSTI]

    Miller, David A. B.

    , and retransmission of digital data. Index Terms--CMOS integrated circuits, optical intercon- nections, optical pulses, system design, and timing issues. Here, we define short pulse optical interconnects as those using-98-1-0002, and a subaward from the University of New Mexico. The authors are with the Departments of Applied Physics

  19. Optical pulse dynamics for quantum-dot logic operations in a photonic-crystal waveguide

    SciTech Connect (OSTI)

    Ma, Xun; John, Sajeev [Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 Canada (Canada)

    2011-11-15

    We numerically demonstrate all-optical logic operations with quantum dots (QDs) embedded in a bimodal photonic-crystal waveguide using Maxwell-Bloch equations in a slowly varying envelope approximation (SVEA). The two-level QD excitation level is controlled by one or more femtojoule optical driving pulses passing through the waveguide. Specific logic operations depend on the relative pulse strengths and their detunings from an inhomogeneouslly broadened (about 1% for QD transitions centered at 1.5 {mu}m) QD transition. This excitation controlled two-level medium then determines passage of subsequent probe optical pulses. Envelope equations for electromagnetic waves in the linear dispersion and cutoff waveguide modes are derived to simplify solution of the coupled Maxwell-Bloch equations in the waveguide. These determine the quantum mechanical evolution of the QD excitation and its polarization, driven by classical electromagnetic (EM) pulses near a sharp discontinuity in the EM density of states of the bimodal waveguide. Different configurations of the driving pulses lead to distinctive relations between driving pulse strength and probe pulse passage, representing all-optical logic and, or, and not operations. Simulation results demonstrate that such operations can be done on picosecond time scales and within a waveguide length of about 10 {mu}m in a photonic-band-gap (PBG) optical microchip.

  20. Composition dependence of the in-plane Cu-O bond-stretching LO phonon mode in YBa2Cu3O6+x

    SciTech Connect (OSTI)

    Stercil, F.; Egami, T.; Mook Jr, Herbert A; Yethiraj, Mohana; Chung, J.-H.; Arai, M.; Frost, C.; Dogan, F.

    2008-01-01

    An inelastic pulsed neutron scattering study was performed on the dependence of the dispersion and spectral intensity of the in-plane Cu-O bond-stretching LO phonon mode on doped charge density. The measurements were made in the time-of-flight mode with the multiangle position sensitive spectrometer of the ISIS facility on single crystals of YBa{sub 2}Cu{sub 3}O{sub 6+x} (x=0.15, 0.35, 0.6, 0.7, and 0.95). The focus of the study is the in-plane Cu-O bond-stretching LO phonon mode, which is known for strong electron-phonon coupling and unusual dependence on composition and temperature. It is shown that the dispersions for the samples with x=0.35, 0.6, and 0.7 are similar to the superposition of those for x=0.15 and 0.95 samples, and cannot be explained in terms of the structural anisotropy. It is suggested that the results are consistent with the model of nanoscale electronic phase separation, with the fraction of the phases being dependent on the doped charge density.

  1. A wide bandwidth free-electron laser with mode locking using current modulation.

    SciTech Connect (OSTI)

    Kur, E.; Dunning, D. J.; McNeil, B. W. J.; Wurtele, J.; Zholents, A. A. )

    2011-01-20

    A new scheme for mode locking a free-electron laser amplifier is proposed based on electron beam current modulation. It is found that certain properties of the original concept, based on the energy modulation of electrons, are improved including the spectral brightness of the source and the purity of the series of short pulses. Numerical comparisons are made between the new and old schemes and between a mode-locked free-electron laser and self-amplified spontaneous emission free-electron laser. Illustrative examples using a hypothetical mode-locked free-electron laser amplifier are provided. The ability to generate intense coherent radiation with a large bandwidth is demonstrated.

  2. Role of laser pre-pulse wavelength and inter-pulse delay on signal enhancement in collinear double-pulse laser-induced

    E-Print Network [OSTI]

    Harilal, S. S.

    Role of laser pre-pulse wavelength and inter-pulse delay on signal enhancement in collinear double-pulse May 2013 Available online 21 May 2013 Keywords: LIBS Double pulse LIBS Plasma diagnostics LPP Dual-pulse as compared to conventional single-pulse LIBS. We investigated collinear DPLIBS experimental per- formance

  3. Pulse compression and modelocking by using TPA in silicon waveguides

    E-Print Network [OSTI]

    Tien, En-Kuang; Yuksek, Nuh S; Qian, Feng; Boyraz, Ozdal

    2007-01-01

    F. Qian, O. Boyraz, “Pulse Compression and Modelocking byPulse compression and modelocking by using TPA in silicona novel broadband pulse compression and modelocking scheme

  4. End-To-End Delay for Hierarchical B-Pictures and Pulsed Quality Dual Frame Video Coders

    E-Print Network [OSTI]

    Leontaris, A; Cosman, P C

    2006-01-01

    DELAY FOR HIERARCHICAL B-PICTURES AND PULSED QUALITY DUALTerms- H.264, hierarchical B-pictures, long-term frames. areclosed-loop hierarchical B pictures," Joint Video Team of

  5. Trapped ion scaling with pulsed fast gates

    E-Print Network [OSTI]

    C. D. B. Bentley; A. R. R. Carvalho; J. J. Hope

    2015-07-10

    Fast entangling gates for trapped ions offer vastly improved gate operation times relative to implemented gates, as well as approaches to trap scaling. Gates on neighbouring ions only involve local ions when performed sufficiently fast, and we find that even a fast gate between distant ions with few degrees of freedom restores all the motional modes given more stringent gate speed conditions. We compare pulsed fast gate schemes, defined by a timescale faster than the trap period, and find that our proposed scheme has less stringent requirements on laser repetition rate for achieving arbitrary gate time targets and infidelities well below $10^{-4}$. By extending gate schemes to ion crystals, we explore the effect of ion number on gate fidelity for coupling neighbouring pairs of ions in large crystals. Inter-ion distance determines the gate time, and a factor of five increase in repetition rate, or correspondingly the laser power, reduces the infidelity by almost two orders of magnitude. We also apply our fast gate scheme to entangle the first and last ions in a crystal. As the number of ions in the crystal increases, significant increases in the laser power are required to provide the short gate times corresponding to fidelity above 0.99.

  6. FREQUENCY DEPENDENCE OF PULSE WIDTH FOR 150 RADIO NORMAL PULSARS

    SciTech Connect (OSTI)

    Chen, J. L. [Department of Physics and Electronic Engineering, Yuncheng University, 044000, Yuncheng, Shanxi (China); Wang, H. G., E-mail: hgwang.gz@gmail.com [Center for Astrophysics, Guangzhou University, 510006, Guangzhou (China)

    2014-11-01

    The frequency dependence of the pulse width is studied for 150 normal pulsars, mostly selected from the European Pulsar Network, for which the 10% multifrequency pulse widths can be well fit with the Thorsett relationship W {sub 10} = A?{sup ?} + W {sub 10,} {sub min}. The relative fraction of pulse width change between 0.4 GHz and 4.85 GHz, ? = (W {sub 4.85} – W {sub 0.4})/W {sub 0.4}, is calculated in terms of the best-fit relationship for each pulsar. It is found that 81 pulsars (54%) have ? < –10% (group A), showing considerable profile narrowing at high frequencies, 40 pulsars (27%) have –10% ?? ? 10% (group B), meaning a marginal change in pulse width, and 29 pulsars (19%) have ? > 10% (group C), showing a remarkable profile broadening at high frequencies. The fractions of the group-A and group-C pulsars suggest that the profile narrowing phenomenon at high frequencies is more common than the profile broadening phenomenon, but a large fraction of the group-B and group-C pulsars (a total of 46%) is also revealed. The group-C pulsars, together with a portion of group-B pulsars with slight pulse broadening, can hardly be explained using the conventional radius-to-frequency mapping, which only applies to the profile narrowing phenomenon. Based on a recent version of the fan beam model, a type of broadband emission model, we propose that the diverse frequency dependence of pulse width is a consequence of different types of distribution of emission spectra across the emission region. The geometrical effect predicting a link between the emission beam shrinkage and spectrum steepening is tested but disfavored.

  7. Pulse enhanced fluidized bed combustion

    SciTech Connect (OSTI)

    Mueller, B.; Golan, L. [South Carolina Energy Research and Development Center, Clemson, SC (United States); Toma, M.; Mansour, M. [Manufacturing and Technology Conversion International, Inc., Columbia, MD (United States)

    1996-12-31

    Various technologies are available for the combustion of high-sulfur, high-ash fuels, particularly coal. From performance, economic and environmental standpoints, fluidized bed combustion (FBC) is the leading candidate for utilization of high sulfur coals. ThermoChem, Inc., and the South Carolina Energy Research and Development Center (SCERDC) are installing a hybrid fluidized bed combustion system at Clemson University. This hybrid system, known as the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC), will augment the University`s steam system by providing 50--60,000 lbs/hr of saturated process steam. The PAFBC, developed by Manufacturing and Technology Conversion International, Inc., (MTCI), integrates a pulse combustor with a bubbling-bed-type atmospheric fluidized bed coal combustor. The pulse combustion system imparts an acoustic effect that enhances combustion efficiency, SO{sub 2} capture, low NO{sub x} emissions, and heat transfer efficiency in the fluidized bed. These benefits of pulse combustion result in modestly sized PAFBC units with high throughput rates and lower costs when compared to conventional fluidized bed units.

  8. Electron geodesic acoustic modes in electron temperature gradient mode turbulence

    SciTech Connect (OSTI)

    Anderson, Johan; Nordman, Hans [Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Singh, Raghvendra; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-08-15

    In this work, the first demonstration of an electron branch of the geodesic acoustic mode (el-GAM) driven by electron temperature gradient (ETG) modes is presented. The work is based on a fluid description of the ETG mode retaining non-adiabatic ions and the dispersion relation for el-GAMs driven nonlinearly by ETG modes is derived. A new saturation mechanism for ETG turbulence through the interaction with el-GAMs is found, resulting in a significantly enhanced ETG turbulence saturation level compared to the mixing length estimate.

  9. Pulse combustion: Devices and applications. (Latest citations from the US Patent database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-04-01

    The bibliography contains citations of selected patents concerning pulse combustion techniques, apparatus, and applications. Pulse combustion devices for burners, furnaces, boilers, ignition and fuel control, heating and drying systems, heat exchangers, and exhaust and noise reduction are presented. Applications for industrial, commercial, and residential space and water heating are considered. (Contains a minimum of 135 citations and includes a subject term index and title list.)

  10. Plasmon mode excitation and photoluminescence enhancement on silver nanoring

    E-Print Network [OSTI]

    Kuchmizhak, A A; Kulchin, Yu N; Vitrik, O B

    2015-01-01

    We demonstrate a simple and high-performance laser-assisted technique for silver nanoring fabrication, which includes the ablation of the Ag film by focused nanosecond pulses and subsequent reactive ion polishing. The nanoring diameter and thickness can be controlled by optimizing both the pulse energy and the metal film thickness at laser ablation step, while the subsequent reactive ion polishing provides the ability to fabricate the nanoring with desirable height. Scattering patterns of s-polarized collimated laser beam obliquely illuminating the nanoring demonstrate the focal spot inside the nanoring shifted from its center at a distance of ~ 0.57Rring. Five-fold enhancement of the photoluminescence signal from the Rhodamine 6G organic dye near the Ag nanoring was demonstrated. This enhancement was attributed to the increase of the electromagnetic field amplitude near the nanoring surface arising from excitation of the multipole plasmon modes traveling along the nanoring. This assumption was confirmed by d...

  11. ULTRASHORT LASER PULSE PROPAGATION IN WATER 

    E-Print Network [OSTI]

    Byeon, Joong-Hyeok

    2010-01-16

    We simulate ultrashort pulse propagation through water by numerical methods, which is a kind of optical communication research. Ultrashort pulses have been known to have non Beer-Lambert behavior, whereas continuous waves ...

  12. Dispersion compensation in chirped pulse amplification systems

    DOE Patents [OSTI]

    Bayramian, Andrew James; Molander, William A.

    2014-07-15

    A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

  13. Predicting non-isometric fatigue induced by electrical stimulation pulse trains as a function of pulse duration

    E-Print Network [OSTI]

    Marion, M Susan; Wexler, Anthony S; Hull, Maury L

    2013-01-01

    of stimulation frequency versus pulse duration modulation onfatigue induced by electrical stimulation pulse trains asa function of pulse duration. Journal of NeuroEngineering

  14. Active mode locking of quantum cascade lasers operating in external ring cavity

    E-Print Network [OSTI]

    Revin, D G; Wang, Y; Cockburn, J W; Belyanin, A

    2015-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode locked operation remains a challenge despite dedicated effort. Here we report the first demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents of a standard commercial laser chip.

  15. Recent advances in long-pulse high-confinement plasma operations in Experimental Advanced Superconducting Tokamak

    SciTech Connect (OSTI)

    Guo, H. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States); Li, J.; Wan, B. N., E-mail: bnwan@ipp.ac.cn; Gong, X. Z.; Xu, G. S.; Zhang, X. D.; Ding, S. Y.; Gan, K. F.; Hu, J. S.; Hu, L. Q.; Liu, S. C.; Qian, J. P.; Sun, Y. W.; Wang, H. Q.; Wang, L.; Xia, T. Y.; Xiao, B. J.; Zeng, L.; Zhao, Y. P. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); and others

    2014-05-15

    A long-pulse high confinement plasma regime known as H-mode is achieved in the Experimental Advanced Superconducting Tokamak (EAST) with a record duration over 30?s, sustained by Lower Hybrid wave Current Drive (LHCD) with advanced lithium wall conditioning and divertor pumping. This long-pulse H-mode plasma regime is characterized by the co-existence of a small Magneto-Hydrodynamic (MHD) instability, i.e., Edge Localized Modes (ELMs) and a continuous quasi-coherent MHD mode at the edge. We find that LHCD provides an intrinsic boundary control for ELMs, leading to a dramatic reduction in the transient power load on the vessel wall, compared to the standard Type I ELMs. LHCD also induces edge plasma ergodization, broadening heat deposition footprints, and the heat transport caused by ergodization can be actively controlled by regulating edge plasma conditions, thus providing a new means for stationary heat flux control. In addition, advanced tokamak scenarios have been newly developed for high-performance long-pulse plasma operations in the next EAST experimental campaign.

  16. for Pulsed Power & erElectronics|Texas

    E-Print Network [OSTI]

    Rock, Chris

    generation, explosive generators, and electric space propulsion engines. Pulsed Power research at Texas Tech for Pulsed Power and Power Electronics Department of Electrical and Computer Engineering Texas Tech- netic generators have also been investigated. The area of pulsed power research involves storing

  17. Pulsed Laser Powered Homogeneous Pyrolysis for

    E-Print Network [OSTI]

    Swihart, Mark T.

    Pulsed Laser Powered Homogeneous Pyrolysis for Reaction Kinetics Studies: Probe Laser Measurement Pulsed laser powered homogeneous pyrolysis ( LPHP) is a technique which can be used to measure rate a number of researchers have shown that pulsed laser powered homogeneous pyrolysis (LPHP) can be used

  18. The Pulse Protocol: Energy Efficient Infrastructure Access

    E-Print Network [OSTI]

    Awerbuch, Baruch

    The Pulse Protocol: Energy Efficient Infrastructure Access Baruch Awerbuch, David Holmer, herb}@cs.jhu.edu Abstract-- We present the Pulse protocol which is designed for multi-hop wireless. The Pulse protocol utilizes a periodic flood initiated at the network gateways which provides both routing

  19. APPARENT PULSE DIFFUSION DUE TO DISORDERED MICROSTRUCTURE

    E-Print Network [OSTI]

    Solna, Knut

    APPARENT PULSE DIFFUSION DUE TO DISORDERED MICROSTRUCTURE A. Nachbin \\Lambda and K. Sølna y \\Lambda, and it is important to describe when and how fine scale heterogeneities interact with a traveling seismic pulse. We are interested in pulse shaped waves that interact with the rapidly varying features (i.e. microstruture

  20. Optical precursor fields in nonlinear pulse dynamics

    E-Print Network [OSTI]

    Oughstun, Kurt

    . Oughstun and G. C. Sherman, Electromagnetic Pulse Propagation in Causal Dielectrics (Springer-Verlag, Berlin-Heidelberg, 1994). 7. K. E. Oughstun, Electromagnetic and Optical Pulse Propagation1: Spectral, 2009). 9. K. E. Oughstun and G. C. Sherman, "Propagation of electromagnetic pulses in a linear

  1. 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)

    2010-04-15

    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.

  2. Efficient Pulse-Doppler Processing and Ambiguity Functions of Nonuniform Coherent Pulse Trains

    E-Print Network [OSTI]

    Nehorai, Arye

    Efficient Pulse-Doppler Processing and Ambiguity Functions of Nonuniform Coherent Pulse Trains Lafayette, Indiana 47907 Email: {srasool, mrb}@purdue.edu Abstract--We propose a DFT based pulse Doppler processing receiver for staggered pulse trains. The proposed receiver is a simple extension of traditional

  3. Multiple colliding electromagnetic pulses: a way to lower the threshold of $e^+e^-$ pair production from vacuum

    E-Print Network [OSTI]

    S. S. Bulanov; V. D. Mur; N. B. Narozhny; J. Nees; V. S. Popov

    2010-03-12

    The scheme of simultaneous multiple pulse focusing on one spot naturally arises from the structural features of projected new laser systems, such as ELI and HiPER. It is shown that the multiple pulse configuration is beneficial for observing $e^+e^-$ pair production from vacuum under the action of sufficiently strong electromagnetic fields. The field of the focused pulses is described using a realistic three-dimensional model based on an exact solution of the Maxwell equations. The $e^+e^-$ pair production threshold in terms of electromagnetic field energy can be substantially lowered if, instead of one or even two colliding pulses, multiple pulses focused on one spot are used. The multiple pulse interaction geometry gives rise to subwavelength field features in the focal region. These features result in the production of extremely short $e^+e^-$ bunches.

  4. Upgrade of the SLAC SLED II Pulse Compression System Based on Recent High Power Tests

    SciTech Connect (OSTI)

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

    2011-09-06

    In the Next Linear Collider (NLC) it is expected that the high power rf components be able to handle peak power levels in excess of 400 MW. We present recent results of high power tests designed to investigate the RF breakdown limits of the X-band pulse compression system used at SLAC. (SLED-II). Results of these tests show that both the TE{sub 01}-TE{sub 10} mode converter and the 4-port hybrid have a maximum useful power limit of 220-250 MW. Based on these tests, modifications of these components have been undertaken to improve their peak field handling capability. Results of these modifications will be presented. As part of an international effort to develop a new 0.5-1.5 TeV electron-positron linear collider for the 21st century, SLAC has been working towards a design, referred to as 'The Next Linear Collider' (NLC), which will operate at 11.424 GHz and utilize 50-75 MW klystrons as rf power sources. One of the major challenges in this design, or any other design, is how to generate and efficiently transport extremely high rf power from a source to an accelerator structure. SLAC has been investigating various methods of 'pulse compressing' a relatively wide rf pulse ({ge} 1 {mu}s) from a klystron into a narrower, but more intense, pulse. Currently a SLED-II pulse compression scheme is being used at SLAC in the NLC Test Accelerator (NLCTA) and in the Accelerator Structures Test Area (ASTA) to provide high rf power for accelerator and component testing. In ASTA, a 1.05 {mu}s pulse from a 50 MW klystron was successfully pulse compressed to 205 MW with a pulse width of 150 ns. Since operation in NLC will require generating and transporting rf power in excess of 400 MW it was decided to test the breakdown limits of the SLED-II rf components in ASTA with rf power up to the maximum available of 400 MW. This required the combining of power from two 50 MW klystrons and feeding the summed power into the SLED-II pulse compressor. Results from this experiment demonstrated that two of the key components of SLED-II; the Magic Tee and the 'Flower Petal' mode converter (converts between TE{sub 10} rectangular and TE{sub 01} circular modes), were not robust enough at higher power levels. Because of this, a major effort is underway to upgrade the existing devices to operate stably at the higher power levels, and also to investigate new components, which have inherently low field enhancement in their design and therefore more robust.

  5. Pulsed Power for Solid-State Lasers

    SciTech Connect (OSTI)

    Gagnon, W; Albrecht, G; Trenholme, J; Newton, M

    2007-04-19

    Beginning in the early 1970s, a number of research and development efforts were undertaken at U.S. National Laboratories with a goal of developing high power lasers whose characteristics were suitable for investigating the feasibility of laser-driven fusion. A number of different laser systems were developed and tested at ever larger scale in pursuit of the optimum driver for laser fusion experiments. Each of these systems had associated with it a unique pulsed power option. A considerable amount of original and innovative engineering was carried out in support of these options. Ultimately, the Solid-state Laser approach was selected as the optimum driver for the application. Following this, the Laser Program at the Lawrence Livermore National Laboratory and the University of Rochester undertook aggressive efforts directed at developing the technology. In particular, at Lawrence Livermore National Laboratory, a series of laser systems beginning with the Cyclops laser and culminating in the present with the National Ignition Facility were developed and tested. As a result, a large amount of design information for solid-state laser pulsed power systems has been documented. Some of it is in the form of published papers, but most of it is buried in internal memoranda, engineering reports and LLNL annual reports. One of the goals of this book is to gather this information into a single useable format, such that it is easily accessed and understood by other engineers and physicists for use with future designs. It can also serve as a primer, which when seriously studied, makes the subsequent reading of original work and follow-up references considerably easier. While this book deals only with the solid-state laser pulsed power systems, in the bibliography we have included a representative cross section of papers and references from much of the very fine work carried out at other institutions in support of different laser approaches. Finally, in recent years, there has been a renewed interest in high-average-power solid-state glass lasers. Much of the prime power technology developed in support of this has definite applications in the long term for fusion power plant scenarios.

  6. Mode-locked solid state lasers using diode laser excitation

    DOE Patents [OSTI]

    Holtom, Gary R. (Boston, MA)

    2012-03-06

    A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. An asymmetric cavity provides relatively large beam spot sizes in gain medium to permit efficient coupling to a volume pumped by a laser diode bar. The cavity can include a collimation region with a controlled beam spot size for insertion of a saturable absorber and dispersion components. Beam spot size is selected to provide stable mode locking based on Kerr lensing. Pulse durations of less than 100 fs can be achieved in Yb:KGW.

  7. Unsplit bipolar pulse forming line

    DOE Patents [OSTI]

    Rhodes, Mark A. (Pleasanton, CA)

    2011-05-24

    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  8. Acoustic emission linear pulse holography

    DOE Patents [OSTI]

    Collins, H.D.; Busse, L.J.; Lemon, D.K.

    1983-10-25

    This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

  9. 140 GHz pulsed Fourier transform microwave spectrometer

    DOE Patents [OSTI]

    Kolbe, W.F.; Leskovar, B.

    1985-07-29

    A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer, including means for generating a high frequency carrier signal, and means for generating a low frequency modulating signal. The carrier signal is continuously fed to a modulator and the modulating signal is fed through a pulse switch to the modulator. When the pulse switch is on, the modulator will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device is tuned to one of the sideband signals and sway from the carrier frequency so that the high frequency energization of the frequency-responsive device is controlled by the pulse switch.

  10. Adaptive control system for pulsed megawatt klystrons

    DOE Patents [OSTI]

    Bolie, Victor W. (Albuquerque, NM)

    1992-01-01

    The invention provides an arrangement for reducing waveform errors such as errors in phase or amplitude in output pulses produced by pulsed power output devices such as klystrons by generating an error voltage representing the extent of error still present in the trailing edge of the previous output pulse, using the error voltage to provide a stored control voltage, and applying the stored control voltage to the pulsed power output device to limit the extent of error in the leading edge of the next output pulse.

  11. Development of double-decker pulse radiolysis

    SciTech Connect (OSTI)

    Kan, K.; Kondoh, T.; Yang, J.; Ogata, A.; Norizawa, K.; Yoshida, Y. [Institute of Scientific and Industrial Research, Osaka University, Osaka (Japan)

    2012-07-15

    Double-decker pulse radiolysis (DDPR), which utilizes double-decker electron beams, was investigated to develop a new pulse radiolysis with a high time resolution. The double-decker electron beams were generated by injecting two UV pulses into a photocathode radio-frequency gun. In the pulse radiolysis, one electron beam was used as a pump beam, and the other was converted to a probe pulse. Finally, as its first application, the DDPR was successfully used for observing solvated electrons in water, with a 10%-90% rise time of 8.6 ps.

  12. Dual amplitude pulse generator for radiation detectors

    DOE Patents [OSTI]

    Hoggan, Jerry M. (Idaho Falls, ID); Kynaston, Ronnie L. (Blackfoot, ID); Johnson, Larry O. (Island Park, ID)

    2001-01-01

    A pulsing circuit for producing an output signal having a high amplitude pulse and a low amplitude pulse may comprise a current source for providing a high current signal and a low current signal. A gate circuit connected to the current source includes a trigger signal input that is responsive to a first trigger signal and a second trigger signal. The first trigger signal causes the gate circuit to connect the high current signal to a pulse output terminal whereas the second trigger signal causes the gate circuit to connect the low current signal to the pulse output terminal.

  13. Ion Acceleration by Short Chirped Laser Pulses

    E-Print Network [OSTI]

    Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán

    2015-01-01

    Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

  14. Intrinsic chirp of single-cycle pulses

    SciTech Connect (OSTI)

    Lin Qiang; Zheng Jian [Institute of Optics, Department of Physics, Zhejiang University, Hangzhou 310027 (China); Dai Jianming; Ho, I-Chen; Zhang, X.-C. [Center for Terahertz Research, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2010-04-15

    The Fourier transform-limited electromagnetic pulse has been regarded to be free of chirps for a long time. This is no longer true if the pulse duration goes down to or less than one optical cycle. We report the experimental observation of intrinsic chirps in such pulses with the sub-single-cycle terahertz (THz) waveforms obtained with a standard THz time-domain spectroscopy system. The results confirm the break down of the carrier-envelope (CE) expression for single-cycle optical pulses, and may influence the experimental measurements and theoretical modeling with single-cycle pulses.

  15. Pulse amplitude modulated chlorophyll fluorometer

    DOE Patents [OSTI]

    Greenbaum, Elias; Wu, Jie

    2015-12-29

    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  16. Solid state pulsed power generator

    DOE Patents [OSTI]

    Tao, Fengfeng; Saddoughi, Seyed Gholamali; Herbon, John Thomas

    2014-02-11

    A power generator includes one or more full bridge inverter modules coupled to a semiconductor opening switch (SOS) through an inductive resonant branch. Each module includes a plurality of switches that are switched in a fashion causing the one or more full bridge inverter modules to drive the semiconductor opening switch SOS through the resonant circuit to generate pulses to a load connected in parallel with the SOS.

  17. Thermal entanglement of bosonic modes

    E-Print Network [OSTI]

    M. Asoudeh

    2006-07-21

    We study the change of entanglement under general linear transformation of modes in a bosonic system and determine the conditions under which entanglement can be generated under such transformation. As an example we consider the thermal entanglement between the vibrational modes of two coupled oscillators and determine the temperature above which quantum correlations are destroyed by thermal fluctuations.

  18. Aerovalve pulse combustion: Technical note

    SciTech Connect (OSTI)

    Richards, G.A.; Gemmen, R.S.; Narayanaswami, L.

    1994-07-01

    The authors present a mathematical model and an experimental investigation of aerodynamically valved pulse combustion. The model uses a control-volume approach to solve conservation laws in several regions of a pulse combustor. Mixing between the fresh charge and combustion products is modeled as a two-step process, with the mixing occurring slowly for a specified eddy time during each cycle, and then changing to a higher rate. Results of model simulations demonstrate that eddy time plays a significant role in determining the frequency and amplitude of combustion oscillation. The authors show that short eddy times produce steady, rather than pulsating, combustion. And they show that changes to the mixing process alter the temperature-species history of combustion gases in a manner that could prevent or promote the formation of nitrogen oxides, depending on specific mixing rates. The relatively simple control-volume approach used in this model allows rapid investigation of a wide range of geometric and operating parameters, and also defines characteristic length and time scales relevant to aerovalve pulse combustion. Experimental measurements compare favorably to model predictions. The authors place particular emphasis on time-averaged pressure differences through the combustor, which act as an indicator of pressure gain performance. They investigate both operating conditions and combustor geometry, and they show that a complex interaction between the inlet and exit flows of a combustor makes it difficult to produce general correlations among the various parameters. They use a scaling rule to produce a combustor geometry capable of producing pressure gain.

  19. Progress in understanding the enhanced pedestal H-mode in NSTX

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

    Gerhardt, S. P.; Canik, J. M.; Maingi, R.; Battaglia, D.; Bell, R. E.; Guttenfelder, W.; LeBlanc, B. P.; Smith, D. R.; Yuh, H.; Sabbagh, S.

    2014-08-01

    The paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from themore »plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.« less

  20. Progress In Understanding The Enhanced Petestal H-mode In NSTX

    SciTech Connect (OSTI)

    Gerhardt, S. P.; Canik, J. M.; Maingi, R.; Battaglia, D.; Bell, R. E.; Guttenfelder, W.; LeBlanc, B. P.; Smith, D. R.; Yuh, H.; Sabbagh, S.

    2014-06-26

    ThIS paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from the plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.

  1. Progress in understanding the enhanced pedestal H-mode in NSTX

    SciTech Connect (OSTI)

    Gerhardt, S. P.; Canik, J. M.; Maingi, R.; Battaglia, D.; Bell, R. E.; Guttenfelder, W.; LeBlanc, B. P.; Smith, D. R.; Yuh, H.; Sabbagh, S.

    2014-08-01

    The paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from the plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.

  2. Microwave pulse compression from a storage cavity with laser-induced switching

    DOE Patents [OSTI]

    Bolton, Paul R. (Menlo Park, CA)

    1992-01-01

    A laser-induced switch and a multiple cavity configuration are disclosed for producing high power microwave pulses. The microwave pulses are well controlled in wavelength and timing, with a quick rise time and a variable shape and power of the pulse. In addition, a method of reducing pre-pulse leakage to a low level is disclosed. Microwave energy is directed coherently to one or more cavities that stores the energy in a single mode, represented as a standing wave pattern. In order to switch the stored microwave energy out of the main cavity and into the branch waveguide, a laser-actuated switch is provided for the cavity. The switch includes a laser, associated optics for delivering the beam into the main cavity, and a switching gas positioned at an antinode in the main cavity. When actuated, the switching gas ionizes, creating a plasma, which becomes reflective to the microwave energy, changing the resonance of the cavity, and as a result the stored microwave energy is abruptly switched out of the cavity. The laser may directly pre-ionize the switching gas, or it may pump an impurity in the switching gas to an energy level which switches when a pre-selected cavity field is attained. Timing of switching the cavities is controlled by varying the pathlength of the actuating laser beam. For example, the pathlengths may be adjusted to output a single pulse of high power, or a series of quick lower power pulses.

  3. Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity

    SciTech Connect (OSTI)

    Bluhm, Robert; Fung Shuhong; Kostelecky, V. Alan

    2008-03-15

    Theories with spontaneous local Lorentz and diffeomorphism violation contain massless Nambu-Goldstone modes, which arise as field excitations in the minimum of the symmetry-breaking potential. If the shape of the potential also allows excitations above the minimum, then an alternative gravitational Higgs mechanism can occur in which massive modes involving the metric appear. The origin and basic properties of the massive modes are addressed in the general context involving an arbitrary tensor vacuum value. Special attention is given to the case of bumblebee models, which are gravitationally coupled vector theories with spontaneous local Lorentz and diffeomorphism violation. Mode expansions are presented in both local and spacetime frames, revealing the Nambu-Goldstone and massive modes via decomposition of the metric and bumblebee fields, and the associated symmetry properties and gauge fixing are discussed. The class of bumblebee models with kinetic terms of the Maxwell form is used as a focus for more detailed study. The nature of the associated conservation laws and the interpretation as a candidate alternative to Einstein-Maxwell theory are investigated. Explicit examples involving smooth and Lagrange-multiplier potentials are studied to illustrate features of the massive modes, including their origin, nature, dispersion laws, and effects on gravitational interactions. In the weak static limit, the massive mode and Lagrange-multiplier fields are found to modify the Newton and Coulomb potentials. The nature and implications of these modifications are examined.

  4. Stress Induced Degradation Modes in CIGSS Minimodules (Presentation)

    SciTech Connect (OSTI)

    Kempe, M. D.; Terwilliger, K.; Tarrant, D.

    2008-05-01

    The experimental objectives of this report are: (1) compare the performance of modules exposed to high temperature and humidity; (2) determine the effects of different encapsulants on long term stability of CIGSS modules; and (3) analyze failure modes to determine areas in need of improvement.

  5. Early-stage Power Grid Analysis for Uncertain Working Modes

    E-Print Network [OSTI]

    Sapatnekar, Sachin

    Early-stage Power Grid Analysis for Uncertain Working Modes Haifeng Qian Department of ECE circuits are now reaching the 100-plus watt regime, and power delivery and power grid signal integrity have and Design Aids General Terms Algorithms, Performance, Design, Reliability Keywords Power grid, Supply

  6. Understanding and Improving High Voltage Vacuum Insulators for Microsecond Pulses

    SciTech Connect (OSTI)

    Javedani, J B; Goerz, D A; Houck, T L; Lauer, E J; Speer, R D; Tully, L K; Vogtlin, G E; White, A D

    2007-03-05

    High voltage insulation is one of the main areas of pulsed power research and development, and dielectric breakdown is usually the limiting factor in attaining the highest possible performance in pulsed power devices. For many applications the delivery of pulsed power into a vacuum region is the most critical aspect of operation. The surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This mode of breakdown, called surface flashover, imposes serious limitations on the power flow into a vacuum region. This is especially troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and for applications where relatively long pulses, on the order of several microseconds, are required. The goal of this project is to establish a sound fundamental understanding of the mechanisms that lead to surface flashover, and then evaluate the most promising techniques to improve vacuum insulators and enable high voltage operation at stress levels near the intrinsic bulk breakdown limits of the material. The approach we proposed and followed was to develop this understanding through a combination of theoretical and computation methods coupled with experiments to validate and quantify expected behaviors. In this report we summarize our modeling and simulation efforts, theoretical studies, and experimental investigations. The computational work began by exploring the limits of commercially available codes and demonstrating methods to examine field enhancements and defect mechanisms at microscopic levels. Plasma simulations with particle codes used in conjunction with circuit models of the experimental apparatus enabled comparisons with experimental measurements. The large scale plasma (LSP) particle-in-cell (PIC) code was run on multiprocessor platforms and used to simulate expanding plasma conditions in vacuum gap regions. Algorithms were incorporated into LSP to handle secondary electron emission from dielectric materials to enable detailed simulations of flashover phenomenon. Theoretical studies were focused on explaining a possible mechanism for anode initiated surface flashover that involves an electron avalanche process starting near the anode, not a mechanism involving bulk dielectric breakdown. Experiments were performed in Engineering's Pulsed Power Lab using an available 100-kV, 10-{micro}s pulse generator and vacuum chamber. The initial experiments were done with polyethylene insulator material in the shape of a truncated cone cut at +45{sup o} angle between flat electrodes with a gap of 1.0 cm. The insulator was sized so there were no flashovers or breakdowns under nominal operating conditions. Insulator flashover or gap closure was induced by introducing a plasma source, a tuft of velvet, in proximity to the insulator or electrode.

  7. Resistive wall mode active control physics design for KSTAR

    SciTech Connect (OSTI)

    Park, Y. S., E-mail: ypark@pppl.gov; Sabbagh, S. A.; Bialek, J. M.; Berkery, J. W. [Department of Applied Physics and Applied Mathematics, Columbia University, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics, Columbia University, New York 10027 (United States); Bak, J. G.; Lee, S. G.; Oh, Y. K. [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of)] [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of)

    2014-01-15

    As KSTAR H-mode operation approaches the region where the resistive wall mode (RWM) can be unstable, an important issue for future long pulse, high beta plasma operation is to evaluate RWM active feedback control performance using a planned active/passive RWM stabilization system on the device. In particular, an optimal design of feedback sensors allows mode stabilization up to the highest achievable ?{sub N} close to the ideal with-wall limit, ?{sub N}{sup wall}, with reduced control power requirements. The computed ideal n?=?1 mode structure from the DCON code has been input to the VALEN-3D code to calculate the projected performance of an active RWM control system in the KSTAR three-dimensional conducting structure device geometry. Control performance with the midplane locked mode detection sensors, off-midplane saddle loops, and magnetic pickup coils is examined. The midplane sensors measuring the radial component of the mode perturbation is found to be strongly affected by the wall eddy current. The off-axis saddle loops with proper compensation of the prompt applied field are computed to provide stabilization at ?{sub N} up to 86% of ?{sub N}{sup wall} but the low RWM amplitude computed in the off-axis regions near the sensors can produce a low signal-to-noise ratio. The required control power and bandwidth are also estimated with varied noise levels in the feedback sensors. Further improvements have been explored by examining a new RWM sensor design motivated by the off-midplane poloidal magnetic field sensors in NSTX. The new sensors mounted off of the copper passive stabilizer plates near the device midplane show a clear advantage in control performance corresponding to achieving 99% of ?{sub N}{sup wall} without the need of compensation of the prompt field. The result shows a significant improvement of RWM feedback stabilization using the new sensor set which motivates a future feedback sensor upgrade.

  8. Pulse Tidal formerly Pulse Generation | 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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc Jump to:Newberg,Energy LLCALLETE Inc dEAPrysmian JumpOpenformerly Pulse

  9. Pulse

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgramExemptionsProteinTotal natural gas provedShale natural

  10. Mode Competition in Dual-Mode Quantum Dots Semiconductor Microlaser

    E-Print Network [OSTI]

    Chusseau, Laurent; Viktorovitch, P; Letartre, Xavier

    2013-01-01

    This paper describes the modeling of quantum dots lasers with the aim of assessing the conditions for stable cw dual-mode operation when the mode separation lies in the THz range. Several possible models suited for InAs quantum dots in InP barriers are analytically evaluated, in particular quantum dots electrically coupled through a direct exchange of excitation by the wetting layer or quantum dots optically coupled through the homogeneous broadening of their optical gain. A stable dual-mode regime is shown possible in all cases when quantum dots are used as active layer whereas a gain medium of quantum well or bulk type inevitably leads to bistable behavior. The choice of a quantum dots gain medium perfectly matched the production of dual-mode lasers devoted to THz generation by photomixing.

  11. Mode Competition in Dual-Mode Quantum Dots Semiconductor Microlaser

    E-Print Network [OSTI]

    Laurent Chusseau; Fabrice Philippe; P. Viktorovitch; Xavier Letartre

    2013-03-07

    This paper describes the modeling of quantum dots lasers with the aim of assessing the conditions for stable cw dual-mode operation when the mode separation lies in the THz range. Several possible models suited for InAs quantum dots in InP barriers are analytically evaluated, in particular quantum dots electrically coupled through a direct exchange of excitation by the wetting layer or quantum dots optically coupled through the homogeneous broadening of their optical gain. A stable dual-mode regime is shown possible in all cases when quantum dots are used as active layer whereas a gain medium of quantum well or bulk type inevitably leads to bistable behavior. The choice of a quantum dots gain medium perfectly matched the production of dual-mode lasers devoted to THz generation by photomixing.

  12. Multi-mode radio frequency device

    DOE Patents [OSTI]

    Gilbert, Ronald W. (Morgan Hill, CA); Carrender, Curtis Lee (Morgan Hill, CA); Anderson, Gordon A. (Benton City, WA); Steele, Kerry D. (Kennewick, WA)

    2007-02-13

    A transponder device having multiple modes of operation, such as an active mode and a passive mode, wherein the modes of operation are selected in response to the strength of a received radio frequency signal. A communication system is also provided having a transceiver configured to transmit a radio frequency signal and to receive a responsive signal, and a transponder configured to operate in a plurality of modes and to activate modes of operation in response to the radio frequency signal. Ideally, each mode of operation is activated and deactivated independent of the other modes, although two or more modes may be concurrently operational.

  13. High-Power Plasma Switch for 11.4 GHz Microwave Pulse Compressor

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2010-03-04

    Results obtained in several experiments on active RF pulse compression at X-band using a magnicon as the high-power RF source are presented. In these experiments, microwave energy was stored in high-Q TE01 and TE02 modes of two parallel-fed resonators, and then discharged using switches activated with rapidly fired plasma discharge tubes. Designs and high-power tests of several versions of the compressor are described. In these experiments, coherent pulse superposition was demonstrated at a 5–9 MW level of incident power. The compressed pulses observed had powers of 50–70 MW and durations of 40–70 ns. Peak power gains were measured to be in the range of 7:1–11:1 with efficiency in the range of 50–63%.

  14. One- and two-dimensional simulations of ultra-short-pulse reflectometry

    SciTech Connect (OSTI)

    Cohen, B.I.; Kaiser, T.B.; Garrison, J.C.

    1997-02-01

    Ultra-short-pulse reflectometry is studied by means of the numerical integration of one- and two-dimensional full-wave equations for ordinary and extraordinary modes propagating in a plasma. The numerical calculations illustrate the use of the reflection of ultra-short-pulse microwaves as an effective probe of the density or magnetic profile in the presence of density or magnetic fluctuations in the plasma. Bragg resonance effects can be identified in the reflected signals, which give information on fluctuations. It is also demonstrated that ultra-short-pulse reflectometry can be used to perform correlation reflectometry measurements in which correlation lengths for density fluctuations are deduced from the observed cross-correlation function of phase shifts as a function of frequency. {copyright} {ital 1997 American Institute of Physics.}

  15. One- and two-dimensional simulations of ultra-short-pulse reflectometry

    SciTech Connect (OSTI)

    Cohen, B.I.; Kaiser, T.B.; Garrison, J.C.

    1997-01-01

    Ultra-short-pulse reflectometry is studied by means of the numerical integration of one- and two-dimensional full-wave equations for ordinary and extraordinary modes propagating in a plasma. The numerical calculations illustrate the use of the reflection of ultra-short-pulse microwaves as an effective probe of the density or magnetic profile in the presence of density or magnetic fluctuations in the plasma. Bragg resonance effects can be identified in the reflected signals, which give information on fluctuations. It is also demonstrated that ultra-short-pulse reflectometry can be used to perform correlation reflectometry measurements in which correlation lengths for density fluctuations are deduced from the observed cross-correlation function of phase shifts as a function of frequency. {copyright} {ital 1997 American Institute of Physics.}

  16. Nuclear Excitation by a Zeptosecond Multi--MeV Laser Pulse

    E-Print Network [OSTI]

    Hans A. Weidenmueller

    2011-03-14

    A zeptosecond multi--MeV laser pulse may either excite a "plasma" of strongly interacting nucleons or a collective mode. We derive the conditions on laser energy and photon number such that either of these scenarios is realized. We use the nuclear Giant Dipole Resonance as a representative example, and a random--matrix description of the fine--structure states and perturbation theory as tools.

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

    E-Print Network [OSTI]

    Levan N. Tsintsadze; Hitoshi Hojo

    2008-10-29

    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.

  18. Collective inertia of Nambu-Goldstone mode from linear response theory

    E-Print Network [OSTI]

    Hinohara, Nobuo

    2015-01-01

    Background: Spurious zero-energy Nambu-Goldstone (NG) modes appear when the symmetry of a system is spontaneously broken. The Thouless-Valatin inertia, the collective inertia of the NG mode, contains important information concerning collective motion. Purpose: To establish an efficient and precise method for deriving the collective inertia and the conjugate operator of a NG mode, we derive an expression for the response function in terms of the coordinate-momentum representation of the quasiparticle random-phase approximation which is valid even if a symmetry-restoring zero-energy mode is present. Methods: We use the finite amplitude method for computing the response function of superfluid nuclei with the nuclear density functional theory. Results: We derived analytically the collective inertia and the conjugate coordinate operator of the NG mode from the zero-energy linear response with the momentum operator of the NG mode. The formulation is tested in the cases of translational and pairing rotational modes....

  19. ALSEP Fligbt Systen1 6 (Array E) System Level Failure Mode Effects

    E-Print Network [OSTI]

    Rathbun, Julie A.

    Gravimeter Experiment (LSGE) +C. S. R =. 8998 Heat Flow Experiment (HFE) +C. S. R =·7972 ~~Passive Seismic housekeeping data (Criticality Rank = IV} Failure modes with a criticality rank of "I'' and "II" are termed

  20. Multi-mode Energy Management for Multi-tier Server Tibor Horvath

    E-Print Network [OSTI]

    Huang, Wei

    Multi-mode Energy Management for Multi-tier Server Clusters Tibor Horvath tibor Charlottesville, VA 22904 ABSTRACT This paper presents an energy management policy for recon- figurable clusters General Terms Algorithms, Design, Experimentation, Management, Perfor- mance Keywords energy management

  1. Chaotic carrier pulse position modulation communication system and method

    DOE Patents [OSTI]

    Abarbanel, Henry D. I. (Del Mar, CA); Larson, Lawrence E. (Del Mar, CA); Rulkov, Nikolai F. (San Diego, CA); Sushchik, Mikhail M. (San Diego, CA); Tsimring, Lev S. (San Diego, CA); Volkovskii, Alexander R. (San Diego, CA)

    2001-01-01

    A chaotic carrier pulse position modulation communication system and method is disclosed. The system includes a transmitter and receiver having matched chaotic pulse regenerators. The chaotic pulse regenerator in the receiver produces a synchronized replica of a chaotic pulse train generated by the regenerator in the transmitter. The pulse train from the transmitter can therefore act as a carrier signal. Data is encoded by the transmitter through selectively altering the interpulse timing between pulses in the chaotic pulse train. The altered pulse train is transmitted as a pulse signal. The receiver can detect whether a particular interpulse interval in the pulse signal has been altered by reference to the synchronized replica it generates, and can therefore detect the data transmitted by the receiver. Preferably, the receiver predicts the earliest moment in time it can expect a next pulse after observation of at least two consecutive pulses. It then decodes the pulse signal beginning at a short time before expected arrival of a pulse.

  2. Analysis of the cryogenic system behavior for pulsed heat load in EAST

    SciTech Connect (OSTI)

    Hu, L. B.; Zhuang, M.; Zhou, Z. W.; Xia, G. H. [Cryogenic Engineering Division, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Shushanhu Road 350, Hefei, Anhui 230031 (China)

    2014-01-29

    EAST is the first full superconducting fusion device. The plasma is confined by the magnetic fields generated from a large set of superconducting magnets which are made of cable in-conduit conductor (CICC). In operation, these magnets suffer heat loads from thermal and nuclear radiation from the surrounding components and plasma as well as the eddy currents and the AC losses generated within the magnets, together with the heat conduction through supports and the resistive heat generated at the current lead transiting to room temperature. The cryogenic system of our EAST consists of a 2kW/4K helium refrigerator and a distribution system for the cooling of poloidal field (PF) and toroidal field (TF) coils, structures, thermal shields, buslines and current leads. Pulsed heat load is the main difference between the cryogenic system of a full superconducting Tokamak system and other large scale cryogenic systems. The cryogenic system operates in a pulsed heat loads mode requiring the helium refrigerator to remove periodically large heat loads in time. At the same time, the cryogenic system parameters such as helium cooling superconducting magnets, helium refrigerator and helium distribution system are changing. In this paper, the variation range of the parameters of superconducting magnets and refrigerator has been analyzed in the typical plasma discharge mode. The control scheme for the pulsed loads characteristics of the cryogenic system has been proposed, the implementation of which helps to smooth the pulse loads and to improve the stability of the operation of the cryogenic system.

  3. Decoherence of interacting Majorana modes

    E-Print Network [OSTI]

    H. T. Ng

    2015-07-31

    We study the decoherence of Majorana modes of a fermion chain, where the fermions interact with their nearest neighbours. We investigate the effect of dissipation and dephasing on the Majorana modes of a fermionic chain. The dissipative and dephasing noises induce the non-parity- and parity-preserving transitions between the eigenstates of the system, respectively. Therefore, these two types of noises lead to the different decoherence mechanisms. In each type of noise, we discuss the low- and high-frequency regimes to describe the different environments. We numerically calculate the dissipation and dephasing rates in the presence of long-range interactions. We find that the decoherence rate of interacting Majorana modes is different to that of non-interacting modes. We show the examples that the long-range interactions can reduce the decoherence rate. It is advantageous to the potential applications of quantum information processing.

  4. Pulse design without rotating wave approximation

    E-Print Network [OSTI]

    S. Ibáñez; Yi-Chao Li; Xi Chen; J. G. Muga

    2015-10-21

    We design realizable time-dependent semiclassical pulses to invert the population of a two-level system faster than adiabatically when the rotating-wave approximation cannot be applied. Different approaches, based on the counterdiabatic method or on invariants, may lead to singularities in the pulse functions. Ways to avoid or cancel the singularities are put forward when the pulse spans few oscillations. For many oscillations an alternative numerical minimization method is proposed and demonstrated.

  5. PULSE DRYING EXPERIMENT AND BURNER CONSTRUCTION

    SciTech Connect (OSTI)

    Robert States

    2006-07-15

    Non steady impingement heat transfer is measured. Impingement heating consumes 130 T-BTU/Yr in paper drying, but is only 25% thermally efficient. Pulse impingement is experimentally shown to enhance heat transfer by 2.8, and may deliver thermal efficiencies near 85%. Experimental results uncovered heat transfer deviations from steady theory and from previous investigators, indicating the need for further study and a better theoretical framework. The pulse burner is described, and its roll in pulse impingement is analyzed.

  6. Observation of the 0-fs pulse

    E-Print Network [OSTI]

    Zare, Richard N.

    Observation of the 0-fs pulse By W.H. Knox, R.S. Knox,J.F.Hoose, and R.N. Zare T he quest for the world's shor test laser pulse has led to a re markable pace of develop ment in ultrafast laser technology. Al though pulses of only a few cycles duration have been made, clearly the observation of a 0-fs

  7. Pulse Areas in Multi-Soliton Propagation

    E-Print Network [OSTI]

    Elizabeth Groves; B. D. Clader; J. H. Eberly

    2008-11-12

    The prospect of self-consistent propagation of more than two pulses contemporaneously through multi-resonant media raises open questions: whether soliton solutions exist, and whether a useful generalization of two-level pulse Area can be found. We answer these questions positively for the case of four pulses interacting in combined V and Lambda fashion with an idealized pair of atomic D-lines.

  8. Pulsed source ion implantation apparatus and method

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA)

    1996-01-01

    A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.

  9. Pulsed source ion implantation apparatus and method

    DOE Patents [OSTI]

    Leung, K.N.

    1996-09-24

    A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted. 16 figs.

  10. Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

    SciTech Connect (OSTI)

    Maget, Patrick, E-mail: patrick.maget@cea.fr; Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Lütjens, Hinrich; Luciani, Jean-François [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)

    2014-06-15

    Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q?=?5/3 and q?=?2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

  11. Mode transition of a Hall thruster discharge plasma

    SciTech Connect (OSTI)

    Hara, Kentaro, E-mail: kenhara@umich.edu; Sekerak, Michael J., E-mail: msekerak@umich.edu; Boyd, Iain D.; Gallimore, Alec D. [University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-05-28

    A Hall thruster is a cross-field plasma device used for spacecraft propulsion. An important unresolved issue in the development of Hall thrusters concerns the effect of discharge oscillations in the range of 10–30?kHz on their performance. The use of a high speed Langmuir probe system and ultra-fast imaging of the discharge plasma of a Hall thruster suggests that the discharge oscillation mode, often called the breathing mode, is strongly correlated to an axial global ionization mode. Stabilization of the global oscillation mode is achieved as the magnetic field is increased and azimuthally rotating spokes are observed. A hybrid-direct kinetic simulation that takes into account the transport of electronically excited atoms is used to model the discharge plasma of a Hall thruster. The predicted mode transition agrees with experiments in terms of the mean discharge current, the amplitude of discharge current oscillation, and the breathing mode frequency. It is observed that the stabilization of the global oscillation mode is associated with reduced electron transport that suppresses the ionization process inside the channel. As the Joule heating balances the other loss terms including the effects of wall loss and inelastic collisions, the ionization oscillation is damped, and the discharge oscillation stabilizes. A wide range of the stable operation is supported by the formation of a space charge saturated sheath that stabilizes the electron axial drift and balances the Joule heating as the magnetic field increases. Finally, it is indicated from the numerical results that there is a strong correlation between the emitted light intensity and the discharge current.

  12. LANL: AOT & LANSCE The Pulse February 2010

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

    interactions, transmembrane ionic transport, membrane structure, and membrane-based biosensors that continued on page 3 Workshop. . . continued from page 1 The Pulse-Newsletter of...

  13. Pulse Pressure Forming of Lightweight Materials, Development...

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

    Materials, Development of High Strength Superplastic Al Sheet, Friction Stir Spot Welding of Advanced High Strength Steels Pulse Pressure Forming of Lightweight Materials,...

  14. LANL: AOT & LANSCE The Pulse September 2010

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

    2 Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division More than 30...

  15. bia-pulse | netl.doe.gov

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

    Inc. Comprehensive Report to Congress Comprehensive Report to Congress on the Clean Coal Technology Program: Demonstration of Pulse Combustion in an Application for Steam...

  16. Train of high-power femtosecond pulses: Probe wave in a gas of prepared atoms

    E-Print Network [OSTI]

    Gevorg Muradyan; A. Zh. Muradyan

    2009-08-21

    We present a new method for generating a regular train of ultrashort optical pulses in a prepared two-level medium. The train develops from incident monochromatic probe radiation travelling in a medium of atoms, which are in a quantum mechanical superposition of dressed internal states. In the frame of used linear theory for the probe radiation, the energy of individual pulses is an exponentially growing function of atom density and of interaction cross section. Pulse repetition rate is determined by the generalized Rabi frequency and can be around 1 THz and greater. We also show that the terms, extra to the dipole approximation, endow the gas by a new property: non-saturating dependence of refractive index on the dressing monochromatic field intensity. Contribution of these nonsaturating terms can be compatible with the main dipole approximation in the wavelength region of about ten micrometers (the range of CO_2 laser) or larger.

  17. PHYSICAL REVIEW A 81, 033828 (2010) Intracavity dynamics in high-power mode-locked fiber lasers

    E-Print Network [OSTI]

    Turitsyn, Sergei K.

    2010-01-01

    PHYSICAL REVIEW A 81, 033828 (2010) Intracavity dynamics in high-power mode-locked fiber lasers the intracavity pulse evolutions in high-power fiber lasers. It is shown that experimentally observed dynamics within a single round trip, this new generation of high-power fiber lasers depends strongly

  18. Evaluation of Some Blockcipher Modes of Operation

    E-Print Network [OSTI]

    Rogaway, Phillip

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4. CBC, CFB, and OFB Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5. CTR; many are widely used. The modes under consideration are the encryption schemes ECB, CBC, CFB, OFB, CTR

  19. X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

    SciTech Connect (OSTI)

    Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong; Tarasenko, Victor; Kostyrya, Igor D.; Ma Hao; Yan Ping

    2012-12-15

    This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30-40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

  20. Quantum chaos with spin-chains in pulsed magnetic fields

    E-Print Network [OSTI]

    T. Boness; M. M. A. Stocklin; T. S. Monteiro

    2006-12-11

    Recently it was found that the dynamics in a Heisenberg spin-chain subjected to a sequence of periodic pulses from an external, parabolic, magnetic field can have a close correspondence with the quantum kicked rotor (QKR). The QKR is a key paradigm of quantum chaos; it has as its classical limit the well-known Standard Map. It was found that a single spin excitation could be converted into a pair of non-dispersive, counter-propagating spin coherent states equivalent to the accelerator modes of the Standard Map. Here we consider how other types of quantum chaotic systems such as a double-kicked quantum rotor or a quantum rotor with a double-well potential might be realized with spin chains; we discuss the possibilities regarding manipulation of the one-magnon spin waves.

  1. Aperiodic dynamical decoupling sequences in presence of pulse errors

    E-Print Network [OSTI]

    Zhi-Hui Wang; V. V. Dobrovitski

    2011-01-12

    Dynamical decoupling (DD) is a promising tool for preserving the quantum states of qubits. However, small imperfections in the control pulses can seriously affect the fidelity of decoupling, and qualitatively change the evolution of the controlled system at long times. Using both analytical and numerical tools, we theoretically investigate the effect of the pulse errors accumulation for two aperiodic DD sequences, the Uhrig's DD UDD) protocol [G. S. Uhrig, Phys. Rev. Lett. {\\bf 98}, 100504 (2007)], and the Quadratic DD (QDD) protocol [J. R. West, B. H. Fong and D. A. Lidar, Phys. Rev. Lett {\\bf 104}, 130501 (2010)]. We consider the implementation of these sequences using the electron spins of phosphorus donors in silicon, where DD sequences are applied to suppress dephasing of the donor spins. The dependence of the decoupling fidelity on different initial states of the spins is the focus of our study. We investigate in detail the initial drop in the DD fidelity, and its long-term saturation. We also demonstrate that by applying the control pulses along different directions, the performance of QDD protocols can be noticeably improved, and explain the reason of such an improvement. Our results can be useful for future implementations of the aperiodic decoupling protocols, and for better understanding of the impact of errors on quantum control of spins.

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

    SciTech Connect (OSTI)

    Andreev, Yu. A. Efremov, A. M.; Koshelev, V. I.; Kovalchuk, B. M.; Petkun, A. A.; Sukhushin, K. N.; Zorkaltseva, M. Yu.

    2014-10-01

    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.

  3. 10 GHz Colliding Pulse Mode Locked Laser with Electrical and Optical Injection Synchronization

    E-Print Network [OSTI]

    Kolner, Brian H.

    past the 1.15Q waveguiding layer with a methane- hydrogen based reactive ion etching (RIE) process Plasma Enhanced Chemical Vapor Deposition (PECVD) SiO2 layer patterned to mask the 2000 µm x 20 µm active

  4. Laser system using ultra-short laser pulses

    DOE Patents [OSTI]

    Dantus, Marcos (Okemos, MI); Lozovoy, Vadim V. (Okemos, MI); Comstock, Matthew (Milford, MI)

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  5. Effect of pulse intensity distributions on fragment internal energy in the infrared multiphoton dissociation of vinyl

    E-Print Network [OSTI]

    Effect of pulse intensity distributions on fragment internal energy in the infrared multiphoton the rovibra- tional energy distributions of fragmentsl formed in the infrared multiphoton dissociation (IRMPD energies of the frag- ment can be well characterized in terms of a Boltzmann distribution with a single

  6. Asymmetric plastic modes in disordered solids

    E-Print Network [OSTI]

    Luka Gartner; Edan Lerner

    2015-07-24

    We propose a framework within which a robust mechanical definition of precursors to plastic instabilities, often termed `soft-spots', naturally emerges. They are shown to be collective displacements (modes) $\\hat{z}_0$ that correspond to local minima of the `barrier function' $b(\\hat{z})$. The latter is derived from the cubic approximation of the variation $\\delta U_{\\hat{z}}(s)$ of the potential energy upon displacing particles a distance $s$ along $\\hat{z}$. We show that modes $\\hat{z}_0$ corresponding to low-lying minima of $b(\\hat{z})$ lead to transitions over energy barriers in the glass, and are therefore associated with highly asymmetric variations $\\delta U_{\\hat{z}}(s)$ with $s$. We further demonstrate how a heuristic search for local minima of $b(\\hat{z})$ can a-priori detect the locus and geometry of imminent plastic instabilities with remarkable accuracy, at strains as large as $\\gamma_c-\\gamma \\sim 10^{-2}$ away from the instability strain $\\gamma_c$, where the non-affine displacements under shear are still largely delocalized. Our findings suggest that the a-priori detection of plastic instabilities can be effectively carried out by the investigation of the landscape of $b(\\hat{z})$.

  7. Nonlinear plastic modes in disordered solids

    E-Print Network [OSTI]

    Luka Gartner; Edan Lerner

    2015-10-27

    We propose a framework within which a robust mechanical definition of precursors to plastic instabilities, often termed `soft-spots', naturally emerges. They are shown to be collective displacements (modes) $\\hat{z}_0$ that correspond to local minima of the `barrier function' $b(\\hat{z})$. The latter is derived from the cubic approximation of the variation $\\delta U_{\\hat{z}}(s)$ of the potential energy upon displacing particles a distance $s$ along $\\hat{z}$. We show that modes $\\hat{z}_0$ corresponding to low-lying minima of $b(\\hat{z})$ lead to transitions over energy barriers in the glass, and are therefore associated with highly asymmetric variations $\\delta U_{\\hat{z}}(s)$ with $s$. We further demonstrate how a heuristic search for local minima of $b(\\hat{z})$ can a-priori detect the locus and geometry of imminent plastic instabilities with remarkable accuracy, at strains as large as $\\gamma_c-\\gamma \\sim 10^{-2}$ away from the instability strain $\\gamma_c$, where the non-affine displacements under shear are still largely delocalized. Our findings suggest that the a-priori detection of plastic instabilities can be effectively carried out by the investigation of the landscape of $b(\\hat{z})$.

  8. X-band photoinjector for a chirped-pulse FEL

    SciTech Connect (OSTI)

    Luhmann, Jr., N. C.; Alvis, R. M.; Baldis, H. A.; Hartemann, F. V; Heritage, J. P.; Ho, C. H.; Landahl, E. C.; Li, K.; Troha,A. L.; White, W. E.

    1998-12-15

    The phase noise and jitter characteristics of the laser and rf systems of a high gradient X-band photoinjector have been measured experimentally. When > 100 coherently phased 5 MeV electron bunches are produced in bursts, the photoinjector should be an ideal electron source for a pulsed, pre-bunched free-electron laser (FEL) operating at 100 GHz. The laser oscillator is a self-modelocked Titanium:Sapphire system operating at the 108th subharmonic of the rf gun. The X-band signal is produced from the laser by a phase-locked dielectric resonance oscillator, and amplified by a pulsed TWT and klystron. A comparison between the klystron and TWT amplifier phase noise and the fields excited in the rf gun demonstrates the filtering effect of the high Q structure, thus indicating that the rf gun can be used as a master oscillator, and could be energized by either a rf oscillator such as a magnetron or a compact source such as a cross-field amplifier. In particular, the rf gun can play the role of a pulsed rf clock to synchronize the photocathode laser system: direct drive of a synchronously mode-locked AlGaAs quantum well laser has been achieved using the X0-band gun rf fields. This novel, GHz repetition rate, sub-picosecond laser system is being developed to replace the more conventional femtosecond Ti: Al2O3 system. Some advantages include pumping this laser with a stabilized current source instead of a costly, low efficiency pump laser. Finally, dark current measurements and initial photoelectron measurements are reported.

  9. Generation of Femtosecond Electron Pulses

    SciTech Connect (OSTI)

    Jinamoon, V.; Kusoljariyakul, K.; Rimjaem, S.; Saisut, J.; Thongbai, C.; Vilaithong, T.; Rhodes, M.W.; Wichaisirimongkol, P.; Chumphongphan, S.; Wiedemann, H.; /SLAC, SSRL

    2005-05-09

    At the Fast Neutron Research Facility (FNRF), Chiang Mai University (Thailand), the SURIYA project has been established aiming to produce femtosecond electron pulses utilizing a combination of an S-band thermionic rf gun and a magnetic bunch compressor ({alpha}-magnet). A specially designed rf-gun has been constructed to obtain optimum beam characteristics for the best bunch compression. Simulation results show that bunch lengths as short as about 50 fs rms can be expected at the experimental station. The electron bunch lengths will be determined using autocorrelation of coherent transition radiation (TR) through a Michelson interferometer. The paper discusses beam dynamics studies, design, fabrication and cold tests of the rf-gun as well as presents the project current status and forth-coming experiments.

  10. Chaos in thermal pulse combustion

    SciTech Connect (OSTI)

    Daw, C.S.; Thomas, J.F. [Engineering Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Engineering Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Richards, G.A. [U.S. Department of Energy, Morgantown Energy Technology Center, Morgantown, West Virginia 26505 (United States)] [U.S. Department of Energy, Morgantown Energy Technology Center, Morgantown, West Virginia 26505 (United States); Narayanaswami, L.L. [Embry-Riddle Aeronautical University, Department of Aerospace Engineering, Daytona Beach, Florida 32114 (United States)] [Embry-Riddle Aeronautical University, Department of Aerospace Engineering, Daytona Beach, Florida 32114 (United States)

    1995-12-01

    An experimental thermal pulse combustor and a differential equation model of this device are shown to exhibit chaotic behavior under certain conditions. Chaos arises in the model by means of a progression of period-doubling bifurcations that occur when operating parameters such as combustor wall temperature or air/fuel flow are adjusted to push the system toward flameout. Bifurcation sequences have not yet been reproduced experimentally, but similarities are demonstrated between the dynamic features of pressure fluctuations in the model and experiment. Correlation dimension, Kolmogorov entropy, and projections of reconstructed attractors using chaotic time series analysis are demonstrated to be useful in classifying dynamical behavior of the experimental combustor and for comparison of test data to the model results. Ways to improve the model are suggested. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. Cryogenic pellet production developments for long-pulse plasma operation

    SciTech Connect (OSTI)

    Meitner, S. J.; Baylor, L. R.; Combs, S. K.; Fehling, D. T.; McGill, J. M.; Duckworth, R. C.; McGinnis, W. D.; Rasmussen, D. A.

    2014-01-29

    Long pulse plasma operation on large magnetic fusion devices require multiple forms of cryogenically formed pellets for plasma fueling, on-demand edge localized mode (ELM) triggering, radiative cooling of the divertor, and impurity transport studies. The solid deuterium fueling and ELM triggering pellets can be formed by extrusions created by helium cooled, twin-screw extruder based injection system that freezes deuterium in the screw section. A solenoid actuated cutter mechanism is activated to cut the pellets from the extrusion, inserting them into the barrel, and then fired by the pneumatic valve pulse of high pressure gas. Fuel pellets are injected at a rate up to 10 Hz, and ELM triggering pellets are injected at rates up to 20 Hz. The radiative cooling and impurity transport study pellets are produced by introducing impurity gas into a helium cooled section of a pipe gun where it deposits in-situ. A pneumatic valve is opened and propellant gas is released downstream where it encounters a passive punch which initially accelerates the pellet before the gas flow around the finishes the pellet acceleration. This paper discusses the various cryogenic pellet production techniques based on the twin-screw extruder, pipe gun, and pellet punch designs.

  12. Harmonic generation with temporally focused ultrashort pulses

    E-Print Network [OSTI]

    Silberberg, Yaron

    Harmonic generation with temporally focused ultrashort pulses Dan Oron and Yaron Silberberg of harmonic generation with temporally focused ultrashort pulses are explored both theoreti- cally and experimentally. Analyzing the phase-matching conditions for harmonic generation we find a corre- spondence

  13. Stably operating pulse combustor and method

    DOE Patents [OSTI]

    Zinn, Ben T. (Atlanta, GA); Reiner, David (Haifa, IL)

    1990-01-01

    A pulse combustor apparatus adapted to burn either a liquid fuel or a pulverized solid fuel within a preselected volume of the combustion chamber. The combustion process is substantially restricted to an optimum combustion zone in order to attain effective pulse combustion operation.

  14. HEAT TRANSFER ANALYSIS OF A PULSE DETONATION

    E-Print Network [OSTI]

    Texas at Arlington, University of

    HEAT TRANSFER ANALYSIS OF A PULSE DETONATION ENGINE by NEELIMA KALIDINDI Presented to the Faculty support. November 23, 2009 #12;iv ABSTRACT HEAT TRANSFER ANALYSIS OF A PULSE DETONATION ENGINE NEELIMA thermal conductivity. The study showed a slow temperature rise along the walls of the combustion chamber

  15. Improving Pulsar Timing Precision with Single Pulses

    E-Print Network [OSTI]

    Kerr, Matthew

    2015-01-01

    The measurement error of pulse times of arrival (TOAs) in the high S/N limit is dominated by the quasi-random variation of a pulsar's emission profile from rotation to rotation. Like measurement noise, this noise is only reduced as the square root of observing time, posing a major challenge to future pulsar timing campaigns with large aperture telescopes, e.g. the Five-hundred-metre Aperture Spherical Telescope and the Square Kilometre Array. We propose a new method of pulsar timing that attempts to approximate the pulse-to-pulse variability with a small family of 'basis' pulses. If pulsar data are integrated over many rotations, this basis can be used to measure sub-pulse structure. Or, if high-time resolution data are available, the basis can be used to 'tag' single pulses and produce an optimal timing template. With realistic simulations, we show that these applications can dramatically reduce the effect of pulse-to-pulse variability on TOAs. Using high-time resolution data taken from the bright PSR J0835-...

  16. Stably operating pulse combustor and method

    DOE Patents [OSTI]

    Zinn, B.T.; Reiner, D.

    1990-05-29

    A pulse combustor apparatus is described which is adapted to burn either a liquid fuel or a pulverized solid fuel within a preselected volume of the combustion chamber. The combustion process is substantially restricted to an optimum combustion zone in order to attain effective pulse combustion operation. 4 figs.

  17. High reliability low jitter pulse generator

    DOE Patents [OSTI]

    Savage, Mark E.; Stoltzfus, Brian S.

    2013-01-01

    A method and concomitant apparatus for generating pulses comprising providing a laser light source, disposing a voltage electrode between ground electrodes, generating laser sparks using the laser light source via laser spark gaps between the voltage electrode and the ground electrodes, and outputting pulses via one or more insulated ground connectors connected to the voltage electrode.

  18. MODEL DG535 Digital Delay / Pulse Generator

    E-Print Network [OSTI]

    Berns, Hans-Gerd

    MODEL DG535 Digital Delay / Pulse Generator 1290-D Reamwood Avenue Sunnyvale, CA 94089 U.S.A. Phone/2000 #12;i DG535 DIGITAL DELAY / PULSE GENERATOR OPERATION AND SERVICE MANUAL Table of Contents CONDENSED Sequence Sheet #4 Rate Generators Sheet #5 Power Supply and Dropout Detection Sheet #6 System Connectors

  19. Optimization of the LCLS Single Pulse Shutter

    SciTech Connect (OSTI)

    Adera, Solomon; /Georgia Tech., Atlanta /SLAC

    2010-08-25

    A mechanical shutter which operates on demand is used to isolate a single pulse from a 120 Hz X-ray source. This is accomplished with a mechanical shutter which is triggered on demand with frequencies ranging from 0 to 10 Hz. The single pulse shutter is an iron blade that oscillates on a pivot in response to a force generated by a pair of pulsed electromagnets (current driven teeter-totter). To isolate an individual pulse from the X-ray beam, the motion of the mechanical shutter should be synchronized in such a way that it allows a single pulse to pass through the aperture and blocks the other incoming pulses. Two consecutive pulses are only {approx} 8 ms apart and the shutter is required to complete one full cycle such that no two pulses pass through the opening. Also the opening of the shutter blade needs to be at least 4 mm so that a 1 mm diameter rms Gaussian beam can pass through without modulation. However, the 4 mm opening is difficult to obtain due to blade rebound and oscillation of the blade after colliding with the electromagnet. The purpose of this project is to minimize and/or totally eliminate the rebound of the shutter blade in pursuit of maximizing the aperture while keeping the open window interval < {approx}12 ms.

  20. A programmable Fresnel transform pulse shaper

    E-Print Network [OSTI]

    Purdue University

    A programmable Fresnel transform pulse shaper G. M´inguez-Vega1, J.D. McKinney2 and A.M. Weiner2 1@purdue.edu Abstract: We demonstrate the first reprogrammable Fresnel transform pulse shaper based on a modified direct a free-space Fresnel transform which causes quadratic dispersion of the output temporal waveform. When

  1. Age dependent modes of extensional necking instability in soft glassy materials

    E-Print Network [OSTI]

    D. M. Hoyle; S. M. Fielding

    2015-04-29

    We study the instability to necking of an initially cylindrical filament of soft glassy material subject to extensional stretching. By numerical simulation of the soft glassy rheology model and a simplified fluidity model, and by analytical predictions within a highly generic toy description, we show that the mode of instability is set by the age of the sample relative to the inverse of the applied extensional strain rate. Young samples neck gradually via a liquid-like mode, the onset of which is determined by both the elastic loading and plastic relaxation terms in the stress constitutive equation. Older samples fail at smaller draw ratios via a more rapid mode, the onset of which is determined only by the solid-like elastic loading terms (though plastic effects arise later, once appreciable necking develops). We show this solid-like mode to be the counterpart, for elastoplastic materials, of the Consid\\`ere mode of necking in strain-rate-independent solids.

  2. Term Pricing Project

    E-Print Network [OSTI]

    Jeff Beckley

    2015-10-29

    Term Pricing Project. Your job is to reprice Purdue Life's 20 Year Term. You are to write a one page memo or report summarizing your work. The report should ...

  3. Infrared pulse characterization using four-wave mixing inside a few cycle pulse filament in air

    SciTech Connect (OSTI)

    Marceau, Claude Thomas, Steven; Kassimi, Yacine; Gingras, Guillaume; Witzel, Bernd

    2014-02-03

    We demonstrate a four-wave mixing (FWM) technique to measure near- and mid-infrared (IR) laser pulse shapes in time domain. Few cycle 800?nm laser pulses were synchronized with the IR pulse and focused colinearly to generate a plasma filament in air. Second harmonic radiation around 400?nm was generated through FWM, with a yield proportional to the IR pulse intensity. Excellent signal to noise ratio was observed from 2.1??m to 18??m. With proper phase stabilization of the IR beam, this technique is a promising step toward direct electric field sensing of near-IR pulses in air.

  4. Sensing mode atomic force microscope

    DOE Patents [OSTI]

    Hough, Paul V. C. (Port Jefferson, NY); Wang, Chengpu (Upton, NY)

    2003-01-01

    An atomic force microscope utilizes a pulse release system and improved method of operation to minimize contact forces between a probe tip affixed to a flexible cantilever and a specimen being measured. The pulse release system includes a magnetic particle affixed proximate the probe tip and an electromagnetic coil. When energized, the electromagnetic coil generates a magnetic field which applies a driving force on the magnetic particle sufficient to overcome adhesive forces exhibited between the probe tip and specimen. The atomic force microscope includes two independently displaceable piezo elements operable along a Z-axis. A controller drives the first Z-axis piezo element to provide a controlled approach between the probe tip and specimen up to a point of contact between the probe tip and specimen. The controller then drives the first Z-axis piezo element to withdraw the cantilever from the specimen. The controller also activates the pulse release system which drives the probe tip away from the specimen during withdrawal. Following withdrawal, the controller adjusts the height of the second Z-axis piezo element to maintain a substantially constant approach distance between successive samples.

  5. Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt laser system

    E-Print Network [OSTI]

    Umstadter, Donald

    Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt investigations of radiation induced chemical events. Electron pulses generated by focussing terawatt laser pulses by the ionizing electron pulses is monitored with 0.3 s time resolution. Hydrated electron concentrations as high

  6. 668 OPTICS LETTERS / Vol. 21, No. 9 / May 1, 1996 Generation of 18-fs, multiterawatt pulses by regenerative pulse

    E-Print Network [OSTI]

    Guo, Ting

    668 OPTICS LETTERS / Vol. 21, No. 9 / May 1, 1996 Generation of 18-fs, multiterawatt pulses by regenerative pulse shaping and chirped-pulse amplification C. P. J. Barty, T. Guo, C. Le Blanc, F. Raksi, C-limited, 18-fs pulses of 4.4-TW peak power are produced in a Ti:sapphire-based chirped-pulsed amplification

  7. Scissors modes: The first overtone

    SciTech Connect (OSTI)

    Hatada, Keisuke [Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); INFN Laboratori Nazionali di Frascati, c.p. 13, I-00044 Frascati (Italy); Hayakawa, Kuniko [INFN Laboratori Nazionali di Frascati, c.p. 13, I-00044 Frascati (Italy); Centro Fermi, Compendio Viminale, Roma I-00184 (Italy); Palumbo, Fabrizio [INFN Laboratori Nazionali di Frascati, c.p. 13, I-00044 Frascati (Italy)

    2011-07-15

    Scissors modes were predicted in the framework of the two-rotor model. This model has an intrinsic harmonic spectrum, so that the level above the scissors mode, the first overtone, has excitation energy twice that of the scissors mode. Because the latter is of the order of 3 MeV in the rare-earth region, the energy of the overtone is below threshold for nucleon emission, and its width should remain small enough for the overtone to be observable. We find that B(E2){up_arrow}{sub overtone}=(1/64 {theta}{sub 0}{sup 2})B(E2){up_arrow}{sub scissors}, where {theta}{sub 0} is the zero-point oscillation amplitude, which in the rare-earth region is of order 10{sup -1}.

  8. 140 GHz pulsed fourier transform microwave spectrometer

    DOE Patents [OSTI]

    Kolbe, William F. (Oakland, CA); Leskovar, Branko (Moraga, CA)

    1987-01-01

    A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer (10), including means (11, 19) for generating a high frequency carrier signal, and means (12) for generating a low frequency modulating signal. The carrier signal is continuously fed to a modulator (20) and the modulating signal is fed through a pulse switch (23) to the modulator. When the pulse switch (23) is on, the modulator (20) will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device (31) is tuned to one of the sideband signals and away from the carrier frequency so that the high frequency energization of the frequency-responsive device (31) is controlled by the pulse switch (23).

  9. 140 GHz pulsed Fourier transform microwave spectrometer

    DOE Patents [OSTI]

    Kolbe, W.F.; Leskovar, B.

    1987-10-27

    A high frequency energy pulsing system suitable for use in a pulsed microwave spectrometer, including means for generating a high frequency carrier signal, and means for generating a low frequency modulating signal is disclosed. The carrier signal is continuously fed to a modulator and the modulating signal is fed through a pulse switch to the modulator. When the pulse switch is on, the modulator will produce sideband signals above and below the carrier signal frequency. A frequency-responsive device is tuned to one of the sideband signals and away from the carrier frequency so that the high frequency energization of the frequency-responsive device is controlled by the pulse switch. 5 figs.

  10. Generation of Femtosecond Electron And Photon Pulses

    SciTech Connect (OSTI)

    Thongbai, C.; Jinamoon, V.; Kangrang, M.; Kusoljariyakul, K.; Rimjaem, S.; Saisut, J.; Vilaithong, T.; Rhodes, M.W.; Wichaisirimongkol, P.; Wiedemann, H.; /SLAC

    2006-03-17

    Femtosecond (fs) electron and photon pulses become a tool of increasing importance to study dynamics in ultrafast processes. Such short electron pulses can be generated from a system consisting of a thermionic-cathode RF-gun and a magnetic bunch compressor. The fs electron pulses can be used directly or used as a source to produce equally short electromagnetic radiation pulses via certain kind of radiation production processes. At the Fast Neutron Research Facility (FNRF), Thailand, we are especially interested in production of radiation in Farinfrared and X-ray regime. In the far-infrared wavelengths, the radiation emitted from fs electron pulses is emitted coherently resulting high intensity radiation. In the X-ray regime, development of fs X-ray sources is crucial for application in ultrafast sciene.

  11. Generation of Femtosecond Electron and Photon Pulses

    E-Print Network [OSTI]

    Thongbai, Chitrlada; Kangrang, Nopadol; Kusoljariyakul, Keerati; Rhodes, Michael W; Rimjaem, Sakhorn; Saisut, Jatuporn; Vilaithong, Thiraphat; Wichaisirimongkol, Pathom; Wiedemann, Helmut

    2005-01-01

    Femtosecond electron and photon pulses become a tool of interesting important to study dynamics at molecular or atomic levels. Such short pulses can be generated from a system consisting of an RF-gun with a thermionic cathode, an alpha magnet as a magnetic bunch compressor, and a linear accelerator. The femtosecond electron pulses can be used directly or used as sources to produce electromagnetic radiation of equally short pulses by choosing certain kind of radiation pruduction processes. At the Fast Neutron Research Facility (Thailand), we are especially interested in production of radiation in Far-infrared and X-ray regime. In the far-infrared wavelengths which are longer than the femtosecond pulse length, the radiation is emitted coherently producing intense radiation. In the X-ray regime, development of femtosecond X-ray source is crucial for application in ultrafast science.

  12. AN UPDATE ON NIF PULSED POWER

    SciTech Connect (OSTI)

    Arnold, P A; James, G F; Petersen, D E; Pendleton, D L; McHale, G B; Barbosa, F; Runtal, A S; Stratton, P L

    2009-06-22

    The National Ignition Facility (NIF) is a 192-beam laser fusion driver operating at Lawrence Livermore National Laboratory. NIF relies on three large-scale pulsed power systems to achieve its goals: the Power Conditioning Unit (PCU), which provides flashlamp excitation for the laser's injection system; the Power Conditioning System (PCS), which provides the multi-megajoule pulsed excitation required to drive flashlamps in the laser's optical amplifiers; and the Plasma Electrode Pockels Cell (PEPC), which enables NIF to take advantage of a fourpass main amplifier. Years of production, installation, and commissioning of the three NIF pulsed power systems are now complete. Seven-day-per-week operation of the laser has commenced, with the three pulsed power systems providing routine support of laser operations. We present the details of the status and operational experience associated with the three systems along with a projection of the future for NIF pulsed power.

  13. Femtosecond pulse shaping using plasmonic snowflake nanoantennas

    SciTech Connect (OSTI)

    Tok, Ruestue Umut; Sendur, Kuersat [Sabanci University, Orhanli-Tuzla, 34956, Istanbul (Turkey)

    2011-09-15

    We have theoretically demonstrated femtosecond pulse manipulation at the nanoscale using the plasmonic snowflake antenna's ability to localize light over a broad spectrum. To analyze the interaction of the incident femtosecond pulse with the plasmonic nanoantenna, we first decompose the diffraction limited incident femtosecond pulse into its spectral components. The interaction of each spectral component with the nanoantenna is analyzed using finite element technique. The time domain response of the plasmonic antenna is obtained using inverse Fourier transformation. It is shown that the rich spectral characteristics of the plasmonic snowflake nanoantenna allow manipulation of the femtosecond pulses over a wide spectrum. Light localization around the gap region of the nanoantenna is shown for femtosecond pulses. As the alignment of incident light polarization is varied, different antenna elements oscillate, which in turn creates a different spectrum and a distinct femtosecond response.

  14. Digital gate pulse generator for cycloconverter control

    DOE Patents [OSTI]

    Klein, Frederick F. (Monroeville, PA); Mutone, Gioacchino A. (Pleasant Hills, PA)

    1989-01-01

    The present invention provides a digital gate pulse generator which controls the output of a cycloconverter used for electrical power conversion applications by determining the timing and delivery of the firing pulses to the switching devices in the cycloconverter. Previous gate pulse generators have been built with largely analog or discrete digital circuitry which require many precision components and periodic adjustment. The gate pulse generator of the present invention utilizes digital techniques and a predetermined series of values to develop the necessary timing signals for firing the switching device. Each timing signal is compared with a reference signal to determine the exact firing time. The present invention is significantly more compact than previous gate pulse generators, responds quickly to changes in the output demand and requires only one precision component and no adjustments.

  15. Pulse combustion: Devices and applications. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect (OSTI)

    NONE

    1995-12-01

    The bibliography contains citations of selected patents concerning pulse combustion techniques, apparatus, and applications. Pulse combustion devices for burners, furnaces, boilers, ignition and fuel control, heating and drying systems, heat exchangers, and exhaust and noise reduction are presented. Applications for industrial, commercial, and residential space and water heating are considered.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  16. Pulse combustion: Devices and applications. (Latest citations from the US Patent Bibliographic File with Exemplary Claims). NewSearch

    SciTech Connect (OSTI)

    Not Available

    1994-10-01

    The bibliography contains citations of selected patents concerning pulse combustion techniques, apparatus, and applications. Pulse combustion devices for burners, furnaces, boilers, ignition and fuel control, heating and drying systems, heat exchangers, and exhaust and noise reduction are presented. Applications for industrial, commercial, and residential space and water heating are considered. (Contains a minimum of 155 citations and includes a subject term index and title list.)

  17. Extension of harmonic cutoff in a multicycle chirped pulse combined with a chirp-free pulse

    SciTech Connect (OSTI)

    Xu Junjie; Zeng Bin; Yu Yongli [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

    2010-11-15

    We demonstrate high-order harmonic generation in a wave form synthesized by a multicycle 800-nm chirped laser pulse and a chirp-free laser pulse. Compared with the case of using only a chirped pulse, both the harmonic cutoff and the extreme ultraviolet supercontinuum can be extended when a weak chirp-free pulse is combined with the chirped pulse. When chirp-free pulse intensity grows, the cutoff energy and bandwidth of the supercontinuum grow as well. It is found that the broad supercontinuum can be achieved for a driving pulse with long duration even though the driving pulse reaches 10 optical cycles. An isolated attosecond pulse with duration of about 59 as is obtained, and after appropriate phase compensation with a duration of about 11 as. In addition, by performing time-frequency analyses and the classical trajectory simulation, the difference in supercontinuum generation between the preceding wave form and a similar wave form synthesized by an 800-nm fundamental pulse and a 1600-nm subharmonic pulse is investigated.

  18. THE LIGHT CURVE AND INTERNAL MAGNETIC FIELD OF THE MODE-SWITCHING PULSAR PSR B0943+10

    SciTech Connect (OSTI)

    Storch, Natalia I.; Lai, Dong [Center for Space Research, Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Ho, Wynn C. G. [Mathematical Sciences and STAG Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Bogdanov, Slavko [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Heinke, Craig O. [Department of Physics, University of Alberta, CCIS 4-181, Edmonton, AB, T6G 2E1 (Canada)

    2014-07-10

    A number of radio pulsars exhibit intriguing mode-switching behavior. Recent observations of PSR B0943+10 revealed correlated radio and X-ray mode switches, providing a new avenue for understanding this class of objects. The large X-ray pulse fraction observed during the radio-quiet phase (Q-mode) was previously interpreted as a result of changing obscuration of X-rays by dense magnetosphere plasma. We show that the large X-ray pulse fraction can be explained by including the beaming effect of a magnetic atmosphere, while remaining consistent with the dipole field geometry constrained by radio observations. We also explore a more extreme magnetic field configuration, where a magnetic dipole displaced from the center of the star produces two magnetic polar caps of different sizes and magnetic field strengths. These models are currently consistent with data in radio and X-rays and can be tested or constrained by future X-ray observations.

  19. Pulse-excited, auto-zeroing multiple channel data transmission system

    DOE Patents [OSTI]

    Fasching, G.E.

    1985-02-22

    A multiple channel data transmission system is provided in which signals from a plurality of pulse operated transducers and a corresponding plurality of pulse operated signal processor channels are multiplexed for single channel FM transmission to a receiving station. The transducers and corresponding channel amplifiers are powered by pulsing the dc battery power to these devices to conserve energy and battery size for long-term data transmission from remote or inaccessible locations. Auto zeroing of the signal channel amplifiers to compensate for drift associated with temperature changes, battery decay, component aging, etc., in each channel is accomplished by means of a unique auto zero feature which between signal pulses holds a zero correction voltage on an integrating capacitor coupled to the corresponding channel amplifier output. Pseudo-continuous outputs for each channel are achieved by pulsed sample-and-hold circuits which are updated at the pulsed operation rate. The sample-and-hold outputs are multiplexed into an FM/FM transmitter for transmission to an FM receiver station for demultiplexing and storage in separate channel recorders.

  20. Pulse-excited, auto-zeroing multiple channel data transmission system

    DOE Patents [OSTI]

    Fasching, George E. (Morgantown, WV)

    1987-01-01

    A multiple channel data transmission system is provided in which signals from a plurality of pulse operated transducers and a corresponding plurality of pulse operated signal processor channels are multiplexed for single channel FM transmission to a receiving station. The transducers and corresponding channel amplifiers are powered by pulsing the dc battery power to these devices to conserve energy and battery size for long-term data transmission from remote or inaccessible locations. Auto zeroing of the signal channel amplifiers to compensate for drift associated with temperature changes, battery decay, component aging, etc., in each channel is accomplished by means of a unique auto zero feature which between signal pulses holds a zero correction voltage on an integrating capacitor coupled to the corresponding channel amplifier output. Pseudo-continuous outputs for each channel are achieved by pulsed sample-and-hold circuits which are updated at the pulsed operation rate. The sample-and-hold outputs are multiplexed into an FM/FM transmitter for transmission to an FM receiver station for demultiplexing and storage in separate channel recorders.

  1. The Homopolar Generator as a Pulsed Industrial Power Supply 

    E-Print Network [OSTI]

    Weldon, J. M.; Weldon, W. F.

    1979-01-01

    power supply for numerous industrial applications such as large metal cross section pulsed resistance welding, pulsed billet heating for subsequent hot working processes, pulsed heating for localized forging processes, and magnetic metal forming. Each...

  2. Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

    E-Print Network [OSTI]

    Cole, Lord Kahil

    2012-01-01

    Combustion and Magnetohydrodynamic Processes in Advanced PulseCombustion and Magnetohydrodynamic Processes in Advanced PulseCombustion Theory and Modeling, 9:159170, [16] Jean-Luc Cambier. Development of numerical tools for pulse

  3. PICOSECOND PULSE SHORTENING USING DYE #5 AS A SATURABLE ABSORBER

    E-Print Network [OSTI]

    George, S.M.

    2012-01-01

    G.H.C. New, "Ultrashort pulse measure- ments", Proc. IEEE,of single picosecond pulses", Opt~ Commun. , vol. Z, pp.h)Lpicosecond light pulses'], Appl. Pbys. Lett. , vol;~ll,-

  4. Reflection and Transmission of Pulsed Electromagnetic Fields through Multilayered

    E-Print Network [OSTI]

    Oughstun, Kurt

    Reflection and Transmission of Pulsed Electromagnetic Fields through Multilayered Biological Media- cally rigorous, physically correct description of the propagation of pulsed electromagnetic fields pulses through multilayered biological media consisting of three biological tissue layers rep- resenting

  5. One-dimensional full wave simulation on XB mode conversion in electron cyclotron heating

    SciTech Connect (OSTI)

    Kim, S. H., E-mail: shkim95@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Lee, H. Y.; Jo, J. G.; Hwang, Y. S. [Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-06-15

    The XB mode conversion in electron cyclotron resonance frequency heating has been studied in detail through 1D full wave simulation. The field pattern depends on the density scale length, and the wave absorption near upper hybrid resonance is maximized beyond the R(X) mode cutoff density for optimized density scale length. The simulated mode conversion efficiency has been compared with that of an analytic formula, showing good agreements except for the phase dependent term of the X wave. The mode conversion efficiency is calculated for oblique injections as well, and it is found that the efficiency decreases as the injection angles increases. Short magnetic field scale length is confirmed to relax the short density scale length condition maximizing the XB mode conversion efficiency. Finally, the simulation code is used to analyze the mode conversion and power absorption of a pre-ionization plasma in versatile experiment spherical torus.

  6. Dispersion relations of Nambu-Goldstone modes at finite temperature and density

    E-Print Network [OSTI]

    Tomoya Hayata; Yoshimasa Hidaka

    2015-03-31

    We discuss the dispersion relations of Nambu-Goldstone (NG) modes associated with spontaneous breaking of internal symmetries at finite temperature and/or density. We show that the dispersion relations of type-A (I) and type-B (II) NG modes are linear and quadratic in momentum, whose imaginary parts are quadratic and quartic, respectively. In both cases, the real parts of the dispersion relations are larger than the imaginary parts when the momentum is small, so that the NG modes can propagate far away. We derive the gap formula for NG modes in the presence of a small explicit breaking term. We also discuss the gapped partners of type-B NG modes, when type-A and type-B NG modes coexist.

  7. Pulse transit time and the pulse wave contour as measured by photoplethysmography: the effect of drugs and exercise 

    E-Print Network [OSTI]

    Payne, Rupert Alistair

    2009-07-07

    Photoplethysmography (PPG) is a simple means of measuring the pulse wave in humans, exploitable for the purposes of timing the arrival of the pulse at a particular point in the arterial tree, and for pulse contour analysis. ...

  8. Transverse pulse shaping and optimization of a tapered hard X...

    Office of Scientific and Technical Information (OSTI)

    Transverse pulse shaping and optimization of a tapered hard X-ray free electron laser Citation Details In-Document Search Title: Transverse pulse shaping and optimization...

  9. Pulse of the Profession - Mike Morgan - Government Relations...

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

    from global organizations and governments around the world Workshop 2015 - PMI 2015 Pulse Knowledge Transfer Presentation for DOE.pdf More Documents & Publications Pulse of the...

  10. Spiraling Laser Pulses Could Change Nature of Graphene

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

    Spiraling Laser Pulses Could Change Nature of Graphene Spiraling Laser Pulses Could Change Nature of Graphene Simulations Run at NERSC Show It Could Transform from Metal to...

  11. System for generating shaped optical pulses and measuring optical pulses using spectral beam deflection (SBD)

    DOE Patents [OSTI]

    Skupsky, S.; Kessler, T.J.; Letzring, S.A.

    1993-11-16

    A temporally shaped or modified optical output pulse is generated from a bandwidth-encoded optical input pulse in a system in which the input pulse is in the form of a beam which is spectrally spread into components contained within the bandwidth, followed by deflection of the spectrally spread beam (SBD) thereby spatially mapping the components in correspondence with the temporal input pulse profile in the focal plane of a lens, and by spatially selective attenuation of selected components in that focal plane. The shaped or modified optical output pulse is then reconstructed from the attenuated spectral components. The pulse-shaping system is particularly useful for generating optical pulses of selected temporal shape over a wide range of pulse duration, such pulses finding application in the fields of optical communication, optical recording and data storage, atomic and molecular spectroscopy and laser fusion. An optical streak camera is also provided which uses SBD to display the beam intensity in the focal plane as a function of time during the input pulse. 10 figures.

  12. Geometric entropy and edge modes of the electromagnetic field

    E-Print Network [OSTI]

    William Donnelly; Aron C. Wall

    2015-06-18

    We calculate the vacuum entanglement entropy of Maxwell theory in a class of curved spacetimes by Kaluza-Klein reduction of the theory onto a two-dimensional base manifold. Using two-dimensional duality, we express the geometric entropy of the electromagnetic field as the entropy of a tower of scalar fields, constant electric and magnetic fluxes, and a contact term, whose leading order divergence was discovered by Kabat. The complete contact term takes the form of one negative scalar degree of freedom confined to the entangling surface. We show that the geometric entropy agrees with a statistical definition of entanglement entropy that includes edge modes: classical solutions determined by their boundary values on the entangling surface. This resolves a longstanding puzzle about the statistical interpretation of the contact term in the entanglement entropy. We discuss the implications of this negative term for black hole thermodynamics and the renormalization of Newton's constant.

  13. Pulsed power hydrodynamics : a new application of high magnetic fields.

    SciTech Connect (OSTI)

    Reinovsky, R. E. (Robert E.); Anderson, W. E. (Wallace E.); Atchison, W. L. (Walter L.); Faehl, R. J. (Rickey J.); Keinigs, R. K. (Rhonald K.); Lindemuth, I. R.; Scudder, D. W. (David W.); Shlachter, Jack S.; Taylor, Antoinette J.,

    2002-01-01

    Pulsed Power Hydrodynamics is a new application of high magnetic fields recently developed to explore advanced hydrodynamics, instabilities, fluid turbulences, and material properties in a highly precise, controllable environment at the extremes of pressure and material velocity. The Atlas facility at Los Alamos is the world's first and only laboratory pulsed power system designed specifically to explore this relatively new family of megagauss magnetic field applications. Constructed in 2000 and commissioned in August 2001, Atlas is a 24-MJ high-performance capacitor bank delivering up to 30 MA with a current risetime of 5-6 {micro}sec. The high-precision, cylindrical, imploding liner is the tool most frequently used to convert electrical energy into the hydrodynamic (particle kinetic) energy needed to drive the experiments. For typical liner parameters including initial radius of 5 cm, the peak current of 30 MA delivered by Atlas results in magnetic fields just over 1 MG outside the liner prior to implosion. During the 5 to 10-{micro}sec implosion, the field outside the liner rises to several MG in typical situations. At these fields the rear surface of the liner is melted and it is subject to a variety of complex behaviors including: diffusion dominated andor melt wave field penetration and heating, magneto Raleigh-Taylor sausage mode behavior at the liner/field interface, and azimuthal asymmetry due to perturbations in current drive. The first Atlas liner implosion experiments were conducted in September 2000 and 10-15 experiments are planned in the: first year of operation. Immediate applications of the new pulsed power hydrodynamics techniques include material property topics including: exploration of material strength at high rates of strain, material failure including fracture and spall, and interfacial dynamics at high relative velocities and high interfacial pressures. A variety of complex hydrodynamic geometries will be explored and experiments will be designed to explore uristable perturbation growth and transition to turbulence. This paper will provide an overview of the range of problems to which pulsed power hydrodynamics can be applied and the issues associated with these techniques. Other papers at this Conference will present specifics of individual experiments and elaborate on the liner physics issues.

  14. 2 MW Active Bouncer Converter Design for Long Pulse Klystron Modulators

    E-Print Network [OSTI]

    Aguglia, D

    2012-01-01

    This paper presents some design issues of a 2 MW interleaved buck converter which is used as an active bouncer droop compensator for a 5.5MW long pulse klystron modulator. This novel design concept presents many challenges in terms of voltage ripple versus pulse rise-time. Issues related to the voltage ripple specification versus output filter design are discussed in detail. The design study is analyzed analytically, simulated numerically and is validated by experimental results obtained from a full power prototype.

  15. Estimation of temporal separation of slow light pulses in atomic vapors by weak measurement

    E-Print Network [OSTI]

    Pardeep Kumar; Shubhrangshu Dasgupta

    2015-03-16

    We show how two circular polarization components of a linearly polarized pulse, propagating through a coherently driven dilute atomic vapor, can be well resolved in time domain by weak measurement. Slower group velocity of one of the components due to electromagnetically induced transparency leads to a differential group delay between the two components. For low number density, this delay may not be large enough to temporally resolve the two components. We show how this can be enhanced in terms of mean time of arrival of the output pulse through a post-selected polarizer. We demonstrate the idea with all the analytical and numerical results, with a specific example of alkali atoms.

  16. Electromagnetically-induced transparency and light storing of a pair of pulses

    E-Print Network [OSTI]

    A. Raczynski; J. Zaremba; S. Zielinska-Kaniasty

    2003-07-30

    Electromagnetically-induced transparency and light storing are studied in the case of a medium of atoms in a double Lambda configuration, both in terms of dark- and bright-state polatitons and atomic susceptibility. It is proven that the medium can be made transparent simultaneously for two pulses following their self-adjusting so that a condition for an adiabatic evolution has become fulfilled. Analytic formulas are given for the shapes and phases of the transmitted/stored pulses. The level of transparency can be regulated by adjusting the heights and phases of the control fields.

  17. Apparatus and method for optical pulse measurement

    DOE Patents [OSTI]

    Trebino, Rick P. (Livermore, CA); Tsang, Thomas (Brooklyn, NY); Fittinghoff, David N. (San Diego, CA); Sweetser, John N. (Livermore, CA); Krumbuegel, Marco A. (Danville, CA)

    1999-12-28

    Practical third-order frequency-resolved optical grating (FROG) techniques for characterization of ultrashort optical pulses are disclosed. The techniques are particularly suited to the measurement of single and/or weak optical pulses having pulse durations in the picosecond and subpicosecond regime. The relative quantum inefficiency of third-order nonlinear optical effects is compensated for through i) use of phase-matched transient grating beam geometry to maximize interaction length, and ii) use of interface-enhanced third-harmonic generation.

  18. Nox reduction system utilizing pulsed hydrocarbon injection

    DOE Patents [OSTI]

    Brusasco, Raymond M. (Livermore, CA); Penetrante, Bernardino M. (San Ramon, CA); Vogtlin, George E. (Fremont, CA); Merritt, Bernard T. (Livermore, CA)

    2001-01-01

    Hydrocarbon co-reductants, such as diesel fuel, are added by pulsed injection to internal combustion engine exhaust to reduce exhaust NO.sub.x to N.sub.2 in the presence of a catalyst. Exhaust NO.sub.x reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbon co-reductants. By means of pulsing the hydrocarbon flow, the amount of pulsed hydrocarbon vapor (itself a pollutant) can be minimized relative to the amount of NO.sub.x species removed.

  19. Pulse propagation in decorated random chains

    E-Print Network [OSTI]

    Upendra Harbola; Alexandre Rosas; Aldo H. Romero; Katja Lindenberg

    2010-05-05

    We study pulse propagation in one-dimensional chains of spherical granules decorated with small randomly-sized granules placed between bigger monodisperse ones. Such "designer chains" are of interest in efforts to control the behavior of the pulse so as to optimize its propagation or attenuation, depending on the desired application. We show that a recently proposed effective description of simple decorated chains can be extended to predict pulse properties in chains decorated with small granules of randomly chosen radii. Furthermore, we also show that the binary collision approximation can again be used to provide analytic results for this system.

  20. SANSPOL at a pulsed source.

    SciTech Connect (OSTI)

    Bleuel, M.; Lang, E.; Krist, T.; Wagner, W.; Lal, J.; Intense Pulsed Neutron Source; Hahn Meitner Inst.; PSI

    2007-07-15

    Neutron polarization has not been implemented successfully on a time-of-flight small angle neutron scattering (TOF-SANS) machine to this date anywhere in the world. Designing a suitable one for the small angle scattering instrument (SASI) at IPNS, and implementing it, is an important first on a pulsed source. To achieve this, the installation of a solid-state supermirror-based polarizer, a gradient field adiabatic spin flipper, and a new collimator package were required. A polarizing solid-state bender without adsorbing layers, designed to transmit one polarized spin state and reflect the other has been purchased from Neutron Optics Berlin (NOB). By placing this package upstream of the collimation only the transmitted spin-state passes through to the sample. The polarization achieved with this technique up to now is 80% for neutrons in a wavelength range of 3-8 Angstroms and 67% for larger wavelengths. The polarizer is placed on a linear translator so it can be easily removed from the beam, when regular SANS measurements are desired. The first experimental results from a two-phase CuNiFe alloy sample are reported here.

  1. Terms and Conditions

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

    Testbed Results Current Testbed Research Proposal Process Terms and Conditions Dark Fiber Testbed Federated Testbed Circuits Test Circuit Service Performance (perfSONAR)...

  2. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOE Patents [OSTI]

    Veligdan, J.T.

    1994-03-08

    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.

  3. Optically controlled delays for broadband pulses 

    E-Print Network [OSTI]

    Sun, Q. Q.; Rostovtsev, Y. V.; Dowling, J. P.; Scully, Marlan O.; Zubairy, M. Suhail

    2005-01-01

    We propose a scheme that provides large controllable delays for broadband optical pulses. The system is based on the steep dispersion of a coherently driven medium, in which the narrow electromagnetically induced transparency (EIT) band is overcome...

  4. Performance of a tapered pulse tube

    SciTech Connect (OSTI)

    Swift, G.; Allen, M.; Woolan, J.J.

    1998-02-01

    In a well instrumented pulse tube refrigerator having 1,500 W of cooling power at 125 K, the authors have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near the operating point for which the taper was designed, the figure of merit is 0.96. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two loss mechanisms: heat conduction in the metal pulse tube wall and ordinary thermoacoustic heat transport in the gas within a few thermal penetration depths of the wall. At operating points farther from the design operating point, the measured figure of merit is much lower, as streaming driven convection adds a third loss mechanism.

  5. Ultrashort Pulse Propagation in the Linear Regime 

    E-Print Network [OSTI]

    Wang, Jieyu

    2010-07-14

    First, we investigate the Bouguer-Lambert-Beer (BLB) law as applied to the transmission of ultrashort pulses through water in the linear absorption regime. We present a linear theory for propagation of ultrashort laser ...

  6. Ultrasonic unipolar pulse/echo instrument

    DOE Patents [OSTI]

    Hughes, Michael S. (Ames, IA); Hsu, David K. (Ames, IA); Thompson, Donald O. (Ames, IA); Wormley, Samuel J. (Ames, IA)

    1993-01-01

    An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

  7. Ultrasonic unipolar pulse/echo instrument

    DOE Patents [OSTI]

    Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

    1993-04-06

    An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

  8. Observations of Radio Giant Pulses with GAVRT

    E-Print Network [OSTI]

    Jones, Glenn

    2015-01-01

    Radio giant pulses provide a unique opportunity to study the pulsar radio emission mechanism in exquisite detail. Previous studies have revealed a wide range of properties and phenomena, including extraordinarily high brightness temperatures, sub-nanosecond emission features, and banded dynamic spectra. New measurements of giant pulse characteristics can help guide and test theoretical emission models. To this end, an extensive observation campaign has begun which will provide more than 500 hours on the Crab with a 34-meter antenna located in California, USA. The observations are being done as part of an educational outreach program called the Goldstone-Apple Valley Radio Telescope (GAVRT). This antenna has a novel wide bandwidth receiver which provides up to 8 GHz of instantaneous bandwidth in the range of 2.5 to 14 GHz. These observations will provide detailed information about the variability, amplitude distribution, and detailed frequency structure of radio giant pulses. In addition, a database of pulses ...

  9. Medical applications of ultrashort pulse lasers

    SciTech Connect (OSTI)

    DaSilva, L.B.; Feit, M.D.; Kim, B.M.; Rubenchil, A.M.

    1999-03-16

    The characteristics of the ultrashort pulse laser (USPL, < 1 ps) ablation of biological tissues are investigated both theoretically and experimentally. Effective USPL parameters for minimal damage and high ablation rates are discussed.

  10. LANL: AOT & LANSCE The Pulse March 2010

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

    Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division I N S I D E 2 Tajima...

  11. LANL: AOT & LANSCE The Pulse July 2012

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

    2 Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division I N S I D E 2 From...

  12. LANL: AOT & LANSCE The Pulse June 2012

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

    2 Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division I N S I D E Singh to...

  13. Post pulse shutter for laser amplifier

    DOE Patents [OSTI]

    Bradley, Laird P. [Livermore, CA; Carder, Bruce M. [Antioch, CA; Gagnon, William L. [Berkeley, CA

    1981-03-17

    Apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse.

  14. Post pulse shutter for laser amplifier

    DOE Patents [OSTI]

    Bradley, L.P.; Carder, B.M.; Gagnon, W.L.

    1981-03-17

    Disclosed are an apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse. 13 figs.

  15. LANL: AOT & LANSCE The Pulse April 2011

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

    1 Los Alamos National Laboratory * Est. 1943 The Pulse-Newsletter of the Los Alamos Neutron Science Center and Accelerator Operations and Technology Division I N S I D E 2 From...

  16. Optimal arbitrarily accurate composite pulse sequences

    E-Print Network [OSTI]

    Low, Guang Hao

    Implementing a single-qubit unitary is often hampered by imperfect control. Systematic amplitude errors ?, caused by incorrect duration or strength of a pulse, are an especially common problem. But a sequence of imperfect ...

  17. Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

    SciTech Connect (OSTI)

    Brown, Jr., C G; Bond, E; Clancy, T; Dangi, S; Eder, D C; Ferguson, W; Kimbrough, J; Throop, A

    2010-02-04

    The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

  18. Semianalytic model of electron pulse propagation: Magnetic lenses and rf pulse compression cavities

    SciTech Connect (OSTI)

    Berger, Joel A.; Schroeder, W. Andreas [Department of Physics, University of Illinois at Chicago, 845 W. Taylor (M/C 273), Chicago, Illinois 60607 (United States)

    2010-12-15

    The analytical Gaussian electron pulse propagation model of Michalik and Sipe [J. Appl. Phys. 99, 054908 (2006)] is extended to include the action of external forces on the pulse. The resultant ability to simulate efficiently the effect of electron optical elements (e.g., magnetic lenses and radio-frequency cavities) allows for the rapid assessment of electron pulse delivery systems in time-resolved ultrafast electron diffraction and microscopy experiments.

  19. Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

    SciTech Connect (OSTI)

    Brown, Jr., C G; Bond, E; Clancy, T; Dangi, S; Eder, D C; Ferguson, W; Kimbrough, J; Throop, A

    2009-10-02

    The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

  20. Modeling pulse profiles of accreting millisecond pulsars

    E-Print Network [OSTI]

    Juri Poutanen

    2008-09-14

    I review the basic observational properties of accreting millisecond pulsars that are important for understanding the physics involved in formation of their pulse profiles. I then discuss main effects responsible for shaping these profiles. Some analytical results that help to understand the results of simulations are presented. Constraints on the pulsar geometry and the neutron star equation of state obtained from the analysis of the pulse profiles are discussed.

  1. Multiple laser pulse ignition method and apparatus

    DOE Patents [OSTI]

    Early, J.W.

    1998-05-26

    Two or more laser light pulses with certain differing temporal lengths and peak pulse powers can be employed sequentially to regulate the rate and duration of laser energy delivery to fuel mixtures, thereby improving fuel ignition performance over a wide range of fuel parameters such as fuel/oxidizer ratios, fuel droplet size, number density and velocity within a fuel aerosol, and initial fuel temperatures. 18 figs.

  2. Ultrashort pulse propagation and the Anderson localization

    E-Print Network [OSTI]

    Silvia Gentilini; Andrea Fratalocchi; Luca Angelani; Giancarlo Ruocco; Claudio Conti

    2008-10-09

    We investigate the dynamics of a 10 fs light pulse propagating in a random medium by the direct solution of the 3D Maxwell equations. Our approach employs molecular dynamics to generate a distribution of spherical scatterers and a parallel finite-difference time-domain code for the vectorial wave propagation. We calculate the disorder-averaged energy velocity and the decay time of the transmitted pulse Versus the localization length for an increasing refractive index.

  3. Electromagnetic or other directed energy pulse launcher

    DOE Patents [OSTI]

    Ziolkowski, Richard W. (Livermore, CA)

    1990-01-01

    The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.

  4. Continuous scanning mode for ptychography

    SciTech Connect (OSTI)

    Clark, Jesse N.; Huang, Xiaojing; Harder, Ross J.; Robinson, Ian K.

    2014-10-15

    We outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. The impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

  5. Continuous scanning mode for ptychography

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

    Clark, Jesse N.; Huang, Xiaojing; Harder, Ross J.; Robinson, Ian K.

    2014-01-01

    We outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. The impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

  6. Real-time multi-mode neutron multiplicity counter

    DOE Patents [OSTI]

    Rowland, Mark S; Alvarez, Raymond A

    2013-02-26

    Embodiments are directed to a digital data acquisition method that collects data regarding nuclear fission at high rates and performs real-time preprocessing of large volumes of data into directly useable forms for use in a system that performs non-destructive assaying of nuclear material and assemblies for mass and multiplication of special nuclear material (SNM). Pulses from a multi-detector array are fed in parallel to individual inputs that are tied to individual bits in a digital word. Data is collected by loading a word at the individual bit level in parallel, to reduce the latency associated with current shift-register systems. The word is read at regular intervals, all bits simultaneously, with no manipulation. The word is passed to a number of storage locations for subsequent processing, thereby removing the front-end problem of pulse pileup. The word is used simultaneously in several internal processing schemes that assemble the data in a number of more directly useable forms. The detector includes a multi-mode counter that executes a number of different count algorithms in parallel to determine different attributes of the count data.

  7. Generation of unipolar pulses from nonunipolar optical pulses in a nonlinear medium

    SciTech Connect (OSTI)

    Kozlov, Victor V. [Department of Information Engineering, Universita degli Studi di Brescia, Via Branze 38, I-25123 Brescia (Italy); Department of Physics, St. Petersburg State University, Petrodvoretz, St. Petersburg, 198504 (Russian Federation); Rosanov, Nikolay N. [Institute of Laser Physics, Vavilov State Optical Institute, Birzhevaya liniya, 12, St. Petersburg, 199034 (Russian Federation); St. Petersburg State University of Information Technologies, Mechanics and Optics, St. Petersburg, 197101 (Russian Federation); De Angelis, Costantino; Wabnitz, Stefan [Department of Information Engineering, Universita degli Studi di Brescia, Via Branze 38, I-25123 Brescia (Italy)

    2011-08-15

    A unipolar electromagnetic pulse is a pulse with nonzero value of the static component of the Fourier spectrum of its real electric field (and not its envelope). We show how to efficiently generate unipolar pulses through propagation of an initially nonunipolar pulse in a nonlinear optical medium. One of the major results is the demonstration that the static component can only be generated in equal portions between the forward- and backward-traveling waves in the presence of nonlinear backscattering in a nonlinear medium.

  8. Dissociative ionization of H{sub 2} in an attosecond pulse train and delayed laser pulse

    SciTech Connect (OSTI)

    He Feng; Thumm, Uwe [James R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas 66506-2604 (United States)

    2010-05-15

    The ionization of H{sub 2} in a single attosecond extreme ultraviolet (XUV) pulse generates a nuclear wave packet in H{sub 2}{sup +}, which is entangled with the emitted photoelectron wave packet. The nuclear wave-packet dynamics can be observed by dissociating H{sub 2}{sup +} in a delayed IR laser pulse. If H{sub 2} is ionized by a sequence of XUV pulses of an attosecond pulse train, whether or not the corresponding sequence of nuclear wave packets in H{sub 2}{sup +} is detected as a coherent or incoherent superposition depends on whether and how the photoelectrons are observed. We simulate the nuclear dynamics in this XUV-pump-IR-probe scenario and analyze our numerical results for both single attosecond pump pulses and pump-pulse trains of different lengths and temporal spacings between individual XUV pulses. By superimposing nuclear wave packets in H{sub 2}{sup +} generated by individual pulses in the pump-pulse train incoherently, we calculate proton kinetic energy release spectra that are in good qualitative agreement with the recent experiment of Kelkensberg et al. [Phys. Rev. Lett. 103, 123005 (2009)].

  9. Tunable pulsed narrow bandwidth light source

    DOE Patents [OSTI]

    Powers, Peter E. (Dayton, OH); Kulp, Thomas J. (Livermore, CA)

    2002-01-01

    A tunable pulsed narrow bandwidth light source and a method of operating a light source are provided. The light source includes a pump laser, first and second non-linear optical crystals, a tunable filter, and light pulse directing optics. The method includes the steps of operating the pump laser to generate a pulsed pump beam characterized by a nanosecond pulse duration and arranging the light pulse directing optics so as to (i) split the pulsed pump beam into primary and secondary pump beams; (ii) direct the primary pump beam through an input face of the first non-linear optical crystal such that a primary output beam exits from an output face of the first non-linear optical crystal; (iii) direct the primary output beam through the tunable filter to generate a sculpted seed beam; and direct the sculpted seed beam and the secondary pump beam through an input face of the second non-linear optical crystal such that a secondary output beam characterized by at least one spectral bandwidth on the order of about 0.1 cm.sup.-1 and below exits from an output face of the second non-linear optical crystal.

  10. Interaction between two stopped light pulses

    SciTech Connect (OSTI)

    Chen, Yi-Hsin, E-mail: yhchen920@gmail.com; Lee, Meng-Jung, E-mail: yhchen920@gmail.com; Hung, Weilun, E-mail: yhchen920@gmail.com; Yu, Ite A., E-mail: yu@phys.nthu.edu.tw [Department of Physics and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Ying-Cheng [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan and Department of Physics and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Yong-Fan [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2014-03-05

    The efficiency of a nonlinear optical process is proportional to the interaction time. We report a scheme of all-optical switching based on two motionless light pulses via the effect of electromagnetically induced transparency. One pulse was stopped as the stationary light pulse (SLP) and the other was stopped as stored light. The time of their interaction via the medium can be prolonged and, hence, the optical nonlinearity is greatly enhanced. Using a large optical density (OD) of 190, we achieved a very long interaction time of 6.9 ?s. This can be analogous to the scheme of trapping light pulses by an optical cavity with a Q factor of 8×10{sup 9}. With the approach of using moving light pulses in the best situation, a switch can only be activated at 2 photons per atomic absorption cross section. With the approach of employing a SLP and a stored light pulse, a switch at only 0.56 photons was achieved and the efficiency is significantly improved. Moreover, the simulation results are in good agreement with the experimental data and show that the efficiency can be further improved by increasing the OD of the medium. Our work advances the technology in quantum information manipulation utilizing photons.

  11. A versatile femtosecond stimulated Raman spectroscopy setup with tunable pulses in the visible to near infrared

    SciTech Connect (OSTI)

    Zhu, Liangdong [Department of Physics, Oregon State University, Corvallis, Oregon 97331 (United States); Liu, Weimin [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States); Fang, Chong, E-mail: Chong.Fang@oregonstate.edu [Department of Physics, Oregon State University, Corvallis, Oregon 97331 (United States); Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2014-07-28

    We demonstrate a versatile and efficient setup to perform femtosecond stimulated Raman spectroscopy (FSRS). Technical innovations are implemented to achieve the wavelength tunability for both the picosecond narrowband Raman pump pulse and femtosecond broadband Raman probe pulse. Using a simplified one-grating scheme in a home-built second harmonic bandwidth compressor followed by a two-stage noncollinear optical parametric amplifier, we tune the Raman pump pulse from ca. 480 to 750?nm. To generate the suitable Raman probe pulse in tandem, we rely on our recently demonstrated broadband up-converted multicolor array technique that readily provides tunable broadband laser sidebands across the visible to near-infrared range. This unique setup has unparalleled flexibility for conducting FSRS. We measure the ground-state Raman spectra of a cyclohexane standard using tunable pump-probe pairs at various wavelengths across the visible region. The best spectral resolution is ?12?cm{sup ?1}. By tuning the pump wavelength closer to the electronic absorption band of a photoacid pyranine in water, we observe the pre-resonantly enhanced Raman signal. The stimulated Raman gain of the 1627?cm{sup ?1} mode is increased by over 15 times.

  12. Coherence Properties of Individual Femtosecond Pulses of an X-ray Free-Electron Laser

    SciTech Connect (OSTI)

    Vartanyants, I.A.; /DESY /Moscow Phys. Eng. Inst.; Singer, A.; Mancuso, A.P.; Yefanov, O.M.; /DESY; Sakdinawat, A.; Liu, Y.; Bang, E.; /UC, Berkeley; Williams, G.J.; /SLAC; Cadenazzi, G.; Abbey, B.; /Melbourne U.; Sinn, H.; /European XFEL, Hamburg; Attwood, D.; /UC, Berkeley; Nugent, K.A.; /Melbourne U.; Weckert, E.; /DESY; Wang, T.; Zhu, D.; Wu, B.; Graves, C.; Scherz, A.; Turner, J.J.; Schlotter, W.F.; /SLAC /LERMA, Ivry /Zurich, ETH /LBL, Berkeley /ANL, APS /Argonne /SLAC /LLNL, Livermore /Latrobe U. /SLAC /SLAC /European XFEL, Hamburg /SLAC /Hamburg U.

    2012-06-06

    Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780 eV x-ray photon energy using apertures containing double pinholes in 'diffract-and-destroy' mode. We determined a coherence length of 17 {micro}m in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55 fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode.

  13. An investigation of the dynamic separation of spot welds under plane tensile pulses

    SciTech Connect (OSTI)

    Ma, Bohan; Fan, Chunlei; Chen, Danian Wang, Huanran; Zhou, Fenghua

    2014-08-07

    We performed ultra-high-speed tests for purely opening spot welds using plane tensile pulses. A gun system generated a parallel impact of a projectile plate onto a welded plate. Induced by the interactions of the release waves, the welded plate opened purely under the plane tensile pulses. We used the laser velocity interferometer system for any reflector to measure the velocity histories of the free surfaces of the free part and the spot weld of the welded plate. We then used a scanning electron microscope to investigate the recovered welded plates. We found that the interfacial failure mode was mainly a brittle fracture and the cracks propagated through the spot nugget, while the partial interfacial failure mode was a mixed fracture comprised ductile fracture and brittle fracture. We used the measured velocity histories to evaluate the tension stresses in the free part and the spot weld of the welded plate by applying the characteristic theory. We also discussed the different constitutive behaviors of the metals under plane shock loading and under uniaxial split Hopkinson pressure bar tests. We then compared the numerically simulated velocity histories of the free surfaces of the free part and the spot weld of the welded plate with the measured results. The numerical simulations made use of the fracture stress criteria, and then the computed fracture modes of the tests were compared with the recovered results.

  14. Pulse combustion: an assessment of opportunities for increased efficiency

    SciTech Connect (OSTI)

    Brenchley, D.L.; Bomelburg, H.J.

    1984-12-01

    The results of a literature review on pulse combustion are discussed. Current, near-future, and potential opportunities for pulse combustion applications are summarized, and the barriers to developing and using pulse combustion technology are discussed, along with research and development needs. Also provided are the proceedings of a pulse combustion workshop held in May, 1984 in Seattle, Washington. (LEW)

  15. SLAC-PUB-7130 PICOSECOND TIMING OF TERAWATT LASER PULSES

    E-Print Network [OSTI]

    pulses and the appropriate diagnostics are described. The jitter between the laser and electron pulses point (IP). The laser pulse crosses the electron beam at an angle of 17-degrees in the horizontal plane delivered pulses of 6 x 109 e­; while the electron beam operated at 10 Hz, collisions occurred at a rate

  16. Pulse Programming for Qubit Transitions Ryan Bowler & Viki Mirgon

    E-Print Network [OSTI]

    Blinov, Boris

    Pulse Programming for Qubit Transitions Ryan Bowler & Viki Mirgon University of Washington Department of Physics Energy levels of Barium 137 Oscilloscope output of the Pulse Programmer Envelope for the microwave control pulses Pulses! Quantum computers have been theorized for many years and are now

  17. Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets

    E-Print Network [OSTI]

    Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley) 243­3130 *Supported by U.S.Department of Energy Contract No. DE­AC02­76CH03073. ABSTRACT Long pulse pulse ignition with DT fuel. 1,2,3,4 Long pulse resistive electromagnets are alternatives to today

  18. COLLIDING PULSE INJECTION CONTROL IN A LASER-PLASMA ACCELERATOR

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    COLLIDING PULSE INJECTION CONTROL IN A LASER-PLASMA ACCELERATOR C.G.R. Geddes , G.R. Plateau, M is presented using the beat between two 'collid- ing' laser pulses to kick electrons into the plasma wake laser pulses [12, 13, 14, 15]. In the colliding pulse technique, the ponderomotive force of the beat

  19. Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets

    E-Print Network [OSTI]

    Long Pulse Fusion Physics Experiments Without Superconducting Electromagnets Robert D. Woolley) 243-3130 *Supported by U.S.Department of Energy Contract No. DE-AC02-76CH03073. ABSTRACT Long pulse pulse ignition with DT fuel. 1,2,3,4 Long pulse resistive electromagnets are alternatives to today

  20. Time-spatial drift of decelerating electromagnetic pulses

    E-Print Network [OSTI]

    Nerukh, Dmitry

    Time-spatial drift of decelerating electromagnetic pulses Alexander G. Nerukh1* and Dmitry A dependent electromagnetic pulse generated by a current running laterally to the direction of the pulse propagation is considered in paraxial approximation. It is shown that the pulse envelope moves in the time

  1. Publish date: 06/27/2011 ECE 4345: Pulsed Power

    E-Print Network [OSTI]

    Gelfond, Michael

    switches. 2. Design basic pulsed power systems including pulse forming lines. 3. Design basic pulsed power of this course students should be able to do the following: 1. Design basic pulsed power systems including (gas, vacuum, liquid, solid, and surface) - 3 hours High power switching (closing and opening) - 5

  2. Pulse homodyne field disturbance sensor

    DOE Patents [OSTI]

    McEwan, T.E.

    1997-10-28

    A field disturbance sensor operates with relatively low power, provides an adjustable operating range, is not hypersensitive at close range, allows co-location of multiple sensors, and is inexpensive to manufacture. The sensor includes a transmitter that transmits a sequence of transmitted bursts of electromagnetic energy. The transmitter frequency is modulated at an intermediate frequency. The sequence of bursts has a burst repetition rate, and each burst has a burst width and comprises a number of cycles at a transmitter frequency. The sensor includes a receiver which receives electromagnetic energy at the transmitter frequency, and includes a mixer which mixes a transmitted burst with reflections of the same transmitted burst to produce an intermediate frequency signal. Circuitry, responsive to the intermediate frequency signal indicates disturbances in the sensor field. Because the mixer mixes the transmitted burst with reflections of the transmitted burst, the burst width defines the sensor range. The burst repetition rate is randomly or pseudo-randomly modulated so that bursts in the sequence of bursts have a phase which varies. A second range-defining mode transmits two radio frequency bursts, where the time spacing between the bursts defines the maximum range divided by two. 12 figs.

  3. Pulse homodyne field disturbance sensor

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1997-01-01

    A field disturbance sensor operates with relatively low power, provides an adjustable operating range, is not hypersensitive at close range, allows co-location of multiple sensors, and is inexpensive to manufacture. The sensor includes a transmitter that transmits a sequence of transmitted bursts of electromagnetic energy. The transmitter frequency is modulated at an intermediate frequency. The sequence of bursts has a burst repetition rate, and each burst has a burst width and comprises a number of cycles at a transmitter frequency. The sensor includes a receiver which receives electromagnetic energy at the transmitter frequency, and includes a mixer which mixes a transmitted burst with reflections of the same transmitted burst to produce an intermediate frequency signal. Circuitry, responsive to the intermediate frequency signal indicates disturbances in the sensor field. Because the mixer mixes the transmitted burst with reflections of the transmitted burst, the burst width defines the sensor range. The burst repetition rate is randomly or pseudo-randomly modulated so that bursts in the sequence of bursts have a phase which varies. A second range-defining mode transmits two radio frequency bursts, where the time spacing between the bursts defines the maximum range divided by two.

  4. Path planning during combustion mode switch

    DOE Patents [OSTI]

    Jiang, Li; Ravi, Nikhil

    2015-12-29

    Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

  5. Interferometric detection of mode splitting for whispering gallery mode biosensors

    E-Print Network [OSTI]

    Knittel, Joachim; Lee, Kwan H; Bowen, Warwick P

    2010-01-01

    Sensors based on whispering gallery mode resonators can detect single nanoparticles and even single molecules. Particles attaching to the resonator induce a doublet in the transmission spectrum which provides a self-referenced detection signal. However, in practice this spectral feature is often obscured by the width of the resonance line which hides the doublet structure. This happens particularly in liquid environments that reduce the effective Q factor of the resonator. In this paper we demonstrate an interferometric set-up that allows the direct detection of the hidden doublet and thus provides a pathway for developing practical sensor applications.

  6. Method for controlling energy density for reliable pulsed laser deposition of thin films

    SciTech Connect (OSTI)

    Dowden, P. C., E-mail: dowden@lanl.gov, E-mail: qxjia@lanl.gov; Bi, Z.; Jia, Q. X., E-mail: dowden@lanl.gov, E-mail: qxjia@lanl.gov [Center for Integrated Nanotechnologies, Division of Materials Physics and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-02-15

    We have established a methodology to stabilize the laser energy density on a target surface in pulsed laser deposition of thin films. To control the focused laser spot on a target, we have imaged a defined aperture in the beamline (so called image-focus) instead of focusing the beam on a target based on a simple “lens-focus.” To control the laser energy density on a target, we have introduced a continuously variable attenuator between the output of the laser and the imaged aperture to manipulate the energy to a desired level by running the laser in a “constant voltage” mode to eliminate changes in the lasers’ beam dimensions. This methodology leads to much better controllability/reproducibility for reliable pulsed laser deposition of high performance electronic thin films.

  7. Microfiber-based gold nanorods as saturable absorber for femtosecond pulse generation in a fiber laser

    SciTech Connect (OSTI)

    Wang, Xu-De [Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong 510006 (China); School of Physics and Electronic Information, Huaibei Normal University, Huaibei, Anhui 235000 (China); Luo, Zhi-Chao; Liu, Hao; Liu, Meng; Luo, Ai-Ping, E-mail: luoaiping@scnu.edu.cn; Xu, Wen-Cheng, E-mail: xuwch@scnu.edu.cn [Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong 510006 (China)

    2014-10-20

    We reported on the femtosecond pulse generation from an erbium-doped fiber (EDF) laser by using microfiber-based gold nanorods (GNRs) as saturable absorber (SA). By virtue of the geometric characteristic of microfiber-based GNRs, the optical damage threshold of GNRs-SA could be greatly enhanced. The microfiber-based GNRs-SA shows a modulation depth of 4.9% and a nonsaturable loss of 21.1%. With the proposed GNRs-SA, the fiber laser emitted a mode-locked pulse train with duration of ?887 fs. The obtained results demonstrated that the GNRs deposited microfiber could indeed serve as a high-performance SA towards the practical applications in the field of ultrafast photonics.

  8. Optical waveguides having flattened high order modes

    DOE Patents [OSTI]

    Messerly, Michael Joseph; Beach, Raymond John; Heebner, John Edward; Dawson, Jay Walter; Pax, Paul Henry

    2014-08-05

    A deterministic methodology is provided for designing optical fibers that support field-flattened, ring-like higher order modes. The effective and group indices of its modes can be tuned by adjusting the widths of the guide's field-flattened layers or the average index of certain groups of layers. The approach outlined here provides a path to designing fibers that simultaneously have large mode areas and large separations between the propagation constants of its modes.

  9. Torsional Oscillations of Relativistic Stars with Dipole Magnetic Fields II. Global Alfvén Modes

    E-Print Network [OSTI]

    H. Sotani; K. D. Kokkotas; N. Stergioulas; M. Vavoulidis

    2006-11-21

    We investigate torsional Alfv\\'{e}n modes of relativistic stars with a global dipole magnetic field. It has been noted recently (Glampedakis et al. 2006) that such oscillation modes could serve as as an alternative explanation (in contrast to torsional crustal modes) for the SGR phenomenon, if the magnetic field is not confined to the crust. We compute global Alfv\\'{e}n modes for a representative sample of equations of state and magnetar masses, in the ideal MHD approximation and ignoring $\\ell \\pm 2$ terms in the eigenfunction. We find that the presence of a realistic crust has a negligible effect on Alfv\\'{e}n modes for $B > 4\\times 10^{15}$ G. Furthermore, we find strong avoided crossings between torsional Alfv\\'{e}n modes and torsional crust modes. For magnetar-like magnetic field strengths, the spacing between consecutive Alfv\\'{e}n modes is of the same order as the gap of avoided crossings. As a result, it is not possible to identify modes of predominantly crustal character and all oscillations are predominantly Alfv\\'{e}n-like. Interestingly, we find excellent agreement between our computed frequencies and observed frequencies in two SGRs, for a maximum magnetic field strenght in the range of (0.8--1.2)$\\times 10^{16}$ G.

  10. Batch-mode Supervised Learning Linear regression

    E-Print Network [OSTI]

    Wehenkel, Louis

    Batch-mode Supervised Learning Linear regression Applied inductive learning - Lecture 3 Louis (& Pierre Geurts)AIA... (1/19) #12;Batch-mode Supervised Learning Linear regression Batch-mode Supervised Learning Linear regression Least mean square error solution Regularization and algorithmics Residual

  11. Hydrodynamic Lyapunov Modes in Translation Invariant Systems

    E-Print Network [OSTI]

    Hydrodynamic Lyapunov Modes in Translation Invariant Systems Jean­Pierre Eckmann and Omri Gat De modes in the slowly growing part of the Lyapunov spectrum, which are analogous to the hydrodynamic modes)]. The hydrodynamic Lyapunov vectors loose the typical random structure and exhibit instead the structure of weakly

  12. Hydrodynamic Lyapunov Modes in Translation Invariant Systems

    E-Print Network [OSTI]

    Eckmann, Jean-Pierre

    Hydrodynamic Lyapunov Modes in Translation Invariant Systems Jean­Pierre Eckmann and Omri Gat De modes in the slowly growing part of the Lyapunov spectrum, which are analogous to the hydrodynamic modes)]. The hydrodynamic Lyapunov vectors loose the typical random structure and exhibit instead the structure of weakly

  13. Injection locked oscillator system for pulsed metal vapor lasers

    DOE Patents [OSTI]

    Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)

    1988-01-01

    An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

  14. Study on electrical characteristics of barrier-free atmospheric air diffuse discharge generated by nanosecond pulses and long wire electrodes

    SciTech Connect (OSTI)

    Li, Lee Liu, Yun-Long; Teng, Yun; Liu, Lun; Pan, Yuan

    2014-07-15

    In room-temperature atmospheric air, the large-scale diffuse plasmas can be generated via high-voltage nanosecond pulses with short rise-time and wire electrodes. Diffuse discharge with the wire electrode length up to 110.0?cm and the discharge spacing of several centimeters has been investigated in this paper. Electrical characteristics of diffuse discharge have been analyzed by their optical photographs and measuring of the voltage and current waveforms. Experimental results show the electrode spacing, and the length of wire electrodes can influence the intensity and mode transition of diffuse discharge. The characteristic of current waveforms is that there are several current oscillation peaks at the time of applied pulsed voltage peak, and at the tail of applied pulse, the conduction current component will compensate the displacement one so that the measured current is unidirectional in diffuse discharge mode. The transition from diffuse discharge to arc discharge is always with the increasing of conduction current density. As for nanosecond pulses with long tail, the long wire electrodes are help for generating non-equilibrium diffuse plasmas.

  15. MULTI-MODE ERROR FIELD CORRECTION ON THE DIII-D TOKAMAK

    SciTech Connect (OSTI)

    SCOVILLE, JT; LAHAYE, RJ

    2002-10-01

    OAK A271 MULTI-MODE ERROR FIELD CORRECTION ON THE DIII-D TOKAMAK. Error field optimization on DIII-D tokamak plasma discharges has routinely been done for the last ten years with the use of the external ''n = 1 coil'' or the ''C-coil''. The optimum level of correction coil current is determined by the ability to avoid the locked mode instability and access previously unstable parameter space at low densities. The locked mode typically has toroidal and poloidal mode numbers n = 1 and m = 2, respectively, and it is this component that initially determined the correction coil current and phase. Realization of the importance of nearby n = 1 mode components m = 1 and m = 3 has led to a revision of the error field correction algorithm. Viscous and toroidal mode coupling effects suggested the need for additional terms in the expression for the radial ''penetration'' field B{sub pen} that can induce a locked mode. To incorporate these effects, the low density locked mode threshold database was expanded. A database of discharges at various toroidal fields, plasma currents, and safety factors was supplement4ed with data from an experiment in which the fields of the n = 1 coil and C-coil were combined, allowing the poloidal mode spectrum of the error field to be varied. A multivariate regression analysis of this new low density locked mode database was done to determine the low density locked mode threshold scaling relationship n{sub e} {proportional_to} B{sub T}{sup -0.01} q{sub 95}{sup -0.79} B{sub pen} and the coefficients of the poloidal mode components in the expression for B{sub pen}. Improved plasma performance is achieved by optimizing B{sub pen} by varying the applied correction coil currents.

  16. New Modes of Nuclear Excitations

    E-Print Network [OSTI]

    Nadia Tsoneva; Horst Lenske

    2013-10-01

    We present a theoretical approach based on density functional theory supplemented by a microscopic multi-phonon model which is applied for investigations of pygmy resonances and other excitations of different multipolarities in stable and exotic nuclei. The possible relation of low-energy modes to the properties of neutron or proton skins is systematically studied in isotonic and isotopic chains. The fine structure of nuclear electric and magnetic response functions is analyzed and compared to experimental data. Their relevance to nuclear astrophysics is discussed.

  17. Mode Meter - Energy Innovation Portal

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGEMission Mission Missionof EnergyJennings= a nMode

  18. Aperiodic dynamical decoupling sequences in presence of pulse errors

    E-Print Network [OSTI]

    Wang, Zhi-Hui

    2011-01-01

    Dynamical decoupling (DD) is a promising tool for preserving the quantum states of qubits. However, small imperfections in the control pulses can seriously affect the fidelity of decoupling, and qualitatively change the evolution of the controlled system at long times. Using both analytical and numerical tools, we theoretically investigate the effect of the pulse errors accumulation for two aperiodic DD sequences, the Uhrig's DD UDD) protocol [G. S. Uhrig, Phys. Rev. Lett. {\\bf 98}, 100504 (2007)], and the Quadratic DD (QDD) protocol [J. R. West, B. H. Fong and D. A. Lidar, Phys. Rev. Lett {\\bf 104}, 130501 (2010)]. We consider the implementation of these sequences using the electron spins of phosphorus donors in silicon, where DD sequences are applied to suppress dephasing of the donor spins. The dependence of the decoupling fidelity on different initial states of the spins is the focus of our study. We investigate in detail the initial drop in the DD fidelity, and its long-term saturation. We also demonstra...

  19. Collective modes in the color flavor-locked phase.

    SciTech Connect (OSTI)

    Anglani, R.; Mannarelli, M.; Ruggieri, M. (Physics); (Univ. of Barcelona); (Kyoto Univ.); (Italian National Research Council)

    2011-05-17

    We study the low-energy effective action for some collective modes of the color flavor-locked (CFL) phase of QCD. This phase of matter has long been known to be a superfluid because by picking a phase its order parameter breaks the quark-number U(1){sub B} symmetry spontaneously. We consider the modes describing fluctuations in the magnitude of the condensate, namely the Higgs mode, and in the phase of the condensate, namely the Nambu-Goldstone (NG) (or Anderson-Bogoliubov) mode associated with the breaking of U(1){sub B}. By employing as microscopic theory the Nambu-Jona-Lasinio model, we reproduce known results for the Lagrangian of the NG field to the leading order in the chemical potential and extend such results evaluating corrections due to the gap parameter. Moreover, we determine the interaction terms between the Higgs and the NG field. This study paves the way for a more reliable study of various dissipative processes in rotating compact stars with a quark matter core in the CFL phase.

  20. Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes

    SciTech Connect (OSTI)

    Nong, Hanond, E-mail: Nong.Hanond@rub.de; Markmann, Sergej; Hekmat, Negar; Jukam, Nathan, E-mail: Nathan.Jukam@rub.de [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Pal, Shovon [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany); Mohandas, Reshma A.; Dean, Paul; Li, Lianhe; Linfield, Edmund H.; Giles Davies, A. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Wieck, Andreas D. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany)

    2014-09-15

    A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.

  1. Suppression of the asymmetric competition mode in the relativistic Ku-band coaxial transit-time oscillator

    SciTech Connect (OSTI)

    Ling, Junpu; He, Juntao; Zhang, Jiande; Jiang, Tao; Wang, Lei [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-10-15

    A relativistic Ku-band coaxial transit-time oscillator has been proposed in our previous work. In the experiments, we find that the asymmetric competition mode in the device limits the microwave power with the increase of the input electric power. For solving such a problem, the methods for analysis and suppression of the asymmetric competition mode in the device are investigated theoretically and experimentally. It is shown that the structure and the material of the collector, the concentricity, and the electron emission uniformity play an important part in the suppression of the asymmetric competition mode in the relativistic Ku-band transit-time oscillator. In the subsequent experiments, the asymmetric mode was suppressed effectively. At a low guiding magnetic field of 0.7?T, a microwave pulse with power of 1?GW, frequency of 14.3?GHz close to the simulation one, and efficiency of 20% was generated.

  2. Multi-pulse particle tracking velocimetry (multi-pulse PTV) is a recently proposed flow measurement technique aiming to improve the performance of conventional PTV/PIV. In this work, multi-pulse PTV

    E-Print Network [OSTI]

    Multi-pulse particle tracking velocimetry (multi-pulse PTV) is a recently proposed flow measurement technique aiming to improve the performance of conventional PTV/PIV. In this work, multi-pulse PTV and acceleration measurement are analytically calculated and compared among quadruple-pulse, triple-pulse and dual-pulse

  3. Quantum Accelerator Modes from the Farey Tree

    E-Print Network [OSTI]

    A. Buchleitner; M. B. d'Arcy; S. Fishman; S. A. Gardiner; I. Guarneri; Z. -Y. Ma; L. Rebuzzini; G. S. Summy

    2006-06-09

    We show that mode-locking finds a purely quantum non-dissipative counterpart in atom-optical quantum accelerator modes. These modes are formed by exposing cold atoms to periodic kicks in the direction of the gravitational field. They are anchored to generalized Arnol'd tongues, parameter regions where driven nonlinear classical systems exhibit mode-locking. A hierarchy for the rational numbers known as the Farey Tree provides an ordering of the Arnol'd tongues and hence of experimentally observed accelerator modes.

  4. Batch-mode vs Online-mode Supervised Learning Motivations for Artificial Neural Networks

    E-Print Network [OSTI]

    Wehenkel, Louis

    Batch-mode vs Online-mode Supervised Learning Motivations for Artificial Neural Networks Linear ANN-mode vs Online-mode Supervised Learning Motivations for Artificial Neural Networks Linear ANN Models for Artificial Neural Networks Linear ANN Models Single neuron models Single layer models Nonlinear ANN Models

  5. Second-Order Nonlinear Mixing of Two Modes in a Planar Photonic Crystal Microcavity

    E-Print Network [OSTI]

    McCutcheon, M W; Dalacu, D; Frederick, S; Poole, P J; Rieger, G W; Williams, R L; Young, J F; Aers, Geof C.; Cutcheon, Murray W. Mc; Dalacu, Dan; Frederick, Simon; Poole, Philip J.; Rieger, Georg W.; Williams, Robin L.; Young, Jeff F.

    2006-01-01

    Polarization-resolved second-harmonic spectra are obtained from the resonant modes of a two-dimensional planar photonic crystal microcavity patterned in a free-standing InP slab. The photonic crystal microcavity is comprised of a single missing-hole defect in a hexagonal photonic crystal host formed with elliptically-shaped holes. The cavity supports two orthogonally-polarized resonant modes split by 60 wavenumbers. Sum-frequency data are reported from the nonlinear interaction of the two coherently excited modes, and the polarization dependence is explained in terms of the nonlinear susceptibility tensor of the host InP.

  6. Hidden explosives detector employing pulsed neutron and x-ray interrogation

    DOE Patents [OSTI]

    Schultz, Frederick J. (Oak Ridge, TN); Caldwell, John T. (Los Alamos, NM)

    1993-01-01

    Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

  7. Hidden explosives detector employing pulsed neutron and x-ray interrogation

    DOE Patents [OSTI]

    Schultz, F.J.; Caldwell, J.T.

    1993-04-06

    Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

  8. The effect of an anisotropic pressure of thermal particles on resistive wall mode stability

    SciTech Connect (OSTI)

    Berkery, J. W. Sabbagh, S. A.; Betti, R.; Guazzotto, L.; Manickam, J.

    2014-11-15

    The effect of an anisotropic pressure of thermal particles on resistive wall mode stability in tokamak fusion plasmas is derived through kinetic theory and assessed through calculation with the MISK code [B. Hu et al., Phys. Plasmas 12, 0?57301 (2005)]. The fluid anisotropy is treated as a small perturbation on the plasma equilibrium and modeled with a bi-Maxwellian distribution function. A complete stability treatment without an assumption of high frequency mode rotation leads to anisotropic kinetic terms in the dispersion relation in addition to anisotropy corrections to the fluid terms. With the density and the average pressure kept constant, when thermal particles have a higher temperature perpendicular to the magnetic field than parallel, the fluid pressure-driven ballooning destabilization term is reduced. Additionally, the stabilizing kinetic effects of the trapped thermal ions can be enhanced. Together these two effects can lead to a modest increase in resistive wall mode stability.

  9. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    SciTech Connect (OSTI)

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18

    This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.

  10. Seismic pulse propagation with constant Q and stable probability distributions

    E-Print Network [OSTI]

    Francesco Mainardi; Massimo Tomirotti

    2010-08-07

    The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type) in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with index of stability determined by the order of the fractional time derivative in the evolution equation.

  11. Laser damage by ns and sub-ps pulses on hafnia/silica anti-reflection coatings on fused silica double-sided polished using zirconia or ceria and washed with or without an alumina wash step.

    SciTech Connect (OSTI)

    Bellum, John Curtis; Rambo, Patrick K.; Schwarz, Jens; Kletecka, Damon; Atherton, Briggs W.; Kimmel, Mark W.; Smith, Ian Craig; Smith, Douglas; Hobbs, Zachary

    2010-10-01

    Sandia's Large Optics Coating Operation has extensive results of laser induced damage threshold (LIDT) testing of its anti-reflection (AR) and high reflection coatings on substrates pitch polished using ceria and washed in a process that includes an alumina wash step. The purpose of the alumina wash step is to remove residual polishing compound to minimize its role in laser damage. These LIDT tests are for multi longitudinal mode, ns class pulses at 1064 nm and 532 nm (NIF-MEL protocol) and mode locked, sub-ps class pulses at 1054 nm (Sandia measurements), and show reasonably high and adequate laser damage resistance for coatings in the beam trains of Sandia's Z-Backlighter terawatt and petawatt lasers. An AR coating in addition to coatings of our previous reports confirms this with LIDTs of 33.0 J/cm{sup 2} for 3.5 ns pulses and 1.8 J/cm{sup 2} for 350 fs pulses. In this paper, we investigate both ceria and zirconia in doublesided polishing (common for large flat Z-Backlighter laser optics) as they affect LIDTs of an AR coating on fused silica substrates washed with or without the alumina wash step. For these AR coated, double-sided polished surfaces, ceria polishing in general affords better resistance to laser damage than zirconia polishing and laser damage is less likely with the alumina wash step than without it. This is supported by specific results of laser damage tests with 3.5 ns, multi longitudinal mode, single shot pulses at 1064 nm and 532 nm, with 7.0 ns, single and multi longitudinal mode, single and multi shot pulses at 532 nm, and with 350 fs, mode-locked, single shot pulses at 1054 nm.

  12. Pulse energy measurement at the SXR instrument

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

    Moeller, Stefan; Brown, Garth; Dakovski, Georgi; Hill, Bruce; Holmes, Michael; Loos, Jennifer; Maida, Ricardo; Paiser, Ernesto; Schlotter, William; Turner, Joshua J.; et al

    2015-04-14

    A gas monitor detector was implemented and characterized at the Soft X-ray Research (SXR) instrument to measure the average, absolute and pulse-resolved photon flux of the LCLS beam in the energy range between 280 and 2000 eV. The detector is placed after the monochromator and addresses the need to provide reliable absolute pulse energy as well as pulse-resolved measurements for the various experiments at this instrument. This detector provides a reliable non-invasive measurement for determining flux levels on the samples in the downstream experimental chamber and for optimizing signal levels of secondary detectors and for the essential need of datamore »normalization. The design, integration into the instrument and operation are described, and examples of its performance are given.« less

  13. Double pulse Thomson scattering system at RTP

    SciTech Connect (OSTI)

    Beurskens, M.N.; Barth, C.J.; Chu, C.C.; Donne, A.J.; Herranz, J.A.; Lopes Cardozo, N.J.; van der Meiden, H.J.; Pijper, F.J. [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Associatie Euratom-FOM, 3430 BE Nieuwegein (The Netherlands)] [FOM-Instituut voor Plasmafysica `Rijnhuizen`, Associatie Euratom-FOM, 3430 BE Nieuwegein (The Netherlands)

    1997-01-01

    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10{endash}800 {mu}s, max. 2{times}12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV{endash}7 keV can be determined with an accuracy as good as 2{percent}{endash}3{percent} for electron densities of 10{sup 20} m{sup {minus}3}, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. {copyright} {ital 1997 American Institute of Physics.}

  14. A Self-Biasing Pulsed Depressed Collector

    SciTech Connect (OSTI)

    Kemp, Mark A.; Jensen, Aaron; Neilson, Jeff; /SLAC

    2014-05-29

    Depressed collectors have been utilized successfully for many years to improve the electrical efficiency of vacuum electron devices. Increasingly, pulsed, high-peak power accelerator applications are placing a premium on electrical efficiency. As RF systems are responsible for a large percentage of the overall energy usage at accelerator laboratories, methods to improve upon the state-of-the-art in pulsed high-power sources are desired. This paper presents a technique for self-biasing the stages in a multistage depressed collector. With this technique, the energy lost during the rise and fall times of the pulse can be recovered, separate power supplies are not needed, and existing modulators can be retrofitted. Calculations show that significant cost savings can be realized with the implementation of this device in high-power systems. In this paper, the technique is described along with experimental demonstration. (auth)

  15. Pulse propagation in a hyper-lattice

    E-Print Network [OSTI]

    Joseph W. Dickey

    2009-07-21

    The classical dynamics and pulse propagation are presented for a series of lattice-like structures whose spatial dimensionality ranges from one to four: four representing a hyper lattice. The lattices are connected one-dimensional wave bearing systems of varying lengths and can illuminate some aspects of higher dimension structures. Short pulses are launched at an arbitrary point, reverberate throughout the entire structure, and detected at another point. Some aspects of increasing dimensionality are illustrated with particular emphasis on the transition from three to four spatial dimensions. In a hypothetical four dimension world where only three are observable, the classical conservation laws and causality do not hold. The lack of causality is illustrated at each step in dimensionality by showing the unexpected pulse returns from the next higher dimension.

  16. Pulsed pyroelectric crystal-powered gamma source

    SciTech Connect (OSTI)

    Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H. [Sandia National Laboratories, Livermore, CA 94550 (United States)

    2013-04-19

    A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as {sup 9}Be(d,n{gamma}){sup 10}B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm{sup 2} and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

  17. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect (OSTI)

    NONE

    1998-03-01

    ThermoChem, under contract to the Department of Energy, conducted extensive research, development and demonstration work on a Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) to confirm that advanced technology can meet these performance objectives. The ThermoChem/MTCI PAFBC system integrates a pulse combustor with an atmospheric bubbling-bed type fluidized bed combustor (BFBC) In this modular configuration, the pulse combustor burns the fuel fines (typically less than 30 sieve or 600 microns) and the fluidized bed combusts the coarse fuel particles. Since the ThermoChem/MTCI PAFBC employs both the pulse combustor and the AFBC technologies, it can handle the full-size range of coarse and fines. The oscillating flow field in the pulse combustor provides for high interphase and intraparticle mass transfer rates. Therefore, the fuel fines essentially burn under kinetic control. Due to the reasonably high temperature (>1093 C but less than the temperature for ash fusion to prevent slagging), combustion of fuel fines is substantially complete at the exit of the pulse combustor. The additional residence time of 1 to 2 seconds in the freeboard of the PAFBC unit then ensures high carbon conversion and, in turn, high combustion efficiency. A laboratory unit was successfully designed, constructed and tested for over 600 hours to confirm that the PAFBC technology could meet the performance objectives. Subsequently, a 50,000 lb/hr PAFBC demonstration steam boiler was designed, constructed and tested at Clemson University in Clemson, South Carolina. This Final Report presents the detailed results of this extensive and successful PAFBC research, development and demonstration project.

  18. Device for generation of pulsed corona discharge

    DOE Patents [OSTI]

    Gutsol, Alexander F. (San Ramon, CA); Fridman, Alexander (Marlton, NJ); Blank, Kenneth (Philadelphia, PA); Korobtsev, Sergey (Moscow, RU); Shiryaevsky, Valery (Moscow, RU); Medvedev, Dmitry (Moscow, RU)

    2012-05-08

    The invention is a method and system for the generation of high voltage, pulsed, periodic corona discharges capable of being used in the presence of conductive liquid droplets. The method and system can be used, for example, in different devices for cleaning of gaseous or liquid media using pulsed corona discharge. Specially designed electrodes and an inductor increase the efficiency of the system, permit the plasma chemical oxidation of detrimental impurities, and increase the range of stable discharge operations in the presence of droplets of water or other conductive liquids in the discharge chamber.

  19. LANSCE | News & Media | The Pulse

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp Graduate student Subtask2 J.N.openNeutronUser ResourcesPulsePulse

  20. ARE PULSING SOLITARY WAVES RUNNING INSIDE THE SUN?

    SciTech Connect (OSTI)

    Wolff, Charles L.

    2012-09-10

    A precise sequence of frequencies-detected four independent ways-is interpreted as a system of solitary waves below the Sun's convective envelope. Six future observational or theoretical tests of this idea are suggested. Wave properties (rotation rates, radial energy distribution, nuclear excitation strength) follow from conventional dynamics of global oscillation modes after assuming a localized nuclear term strong enough to perturb and hold mode longitudes into alignments that form 'families'. To facilitate future tests, more details are derived for a system of two dozen solitary waves 2 {<=} l {<=} 25. Wave excitation by {sup 3}He and {sup 14}C burning is complex. It spikes by factors M{sub 1} {<=} 10{sup 3} when many waves overlap in longitude but its long-time average is M{sub 2} {<=} 10. Including mixing can raise overall excitation to {approx}50 times that in a standard solar model. These spikes cause tiny phase shifts that tend to pull wave rotation rates toward their ideal values {proportional_to}[l(l + 1)]{sup -1}. A system like this would generate some extra nuclear energy in two spots at low latitude on opposite sides of the Sun. Each covers about 20 Degree-Sign of longitude. Above a certain wave amplitude, the system starts giving distinctly more nuclear excitation to some waves (e.g., l = 9, 14, and 20) than to neighboring l values. The prominence of l = 20 has already been reported. This transition begins at temperature amplitudes {Delta}T/T = 0.03 in the solar core for a typical family of modes, which corresponds to {delta}T/T {approx} 0.001 for one of its many component oscillation modes.

  1. A Summary of Taxonomies of Digital System Failure Modes Provided by the DigRel Task Group

    SciTech Connect (OSTI)

    Chu T. L.; Yue M.; Postma, W.

    2012-06-25

    Recently, the CSNI directed WGRisk to set up a task group called DIGREL to initiate a new task on developing a taxonomy of failure modes of digital components for the purposes of PSA. It is an important step towards standardized digital I&C reliability assessment techniques for PSA. The objective of this paper is to provide a comparison of the failure mode taxonomies provided by the participants. The failure modes are classified in terms of their levels of detail. Software and hardware failure modes are discussed separately.

  2. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network

    SciTech Connect (OSTI)

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-15

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory.

  3. Precision lifetime measurement of the cesium $6P_{3/2}$ level using ultrafast pump-probe laser pulses

    E-Print Network [OSTI]

    Patterson, Brian M; Ehrenreich, Thomas; Gearba, Mirela A; Brooke, George M; Scoville, James; Knize, Randy J

    2014-01-01

    Using the inherent timing stability of pulses from a mode-locked laser, we have precisely measured the cesium $6P_{3/2}$ excited state lifetime. An initial pump pulse excites cesium atoms in two counter-propagating atomic beams to the $6P_{3/2}$ level. A subsequent synchronized probe pulse ionizes atoms which remain in the excited state, and the photo-ions are collected and counted. By selecting pump pulses which vary in time with respect to the probe pulses, we obtain a sampling of the excited state population in time, resulting in a lifetime value of 30.462(46) ns. The measurement uncertainty (0.15%) is larger than our previous report of 0.12% [Phys. Rev. A 84, 010501(R) (2011)] due to the inclusion of additional data and systematic errors. In this follow-up paper we present details of the primary systematic errors encountered in the measurement, which include atomic motion within the intensity profiles of the laser beams, quantum beating in the photo-ion signal, and radiation trapping. Improvements to furt...

  4. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials

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

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H.; Azad, Abul; Marshall, Bruce; La Lone, Brandon M.; Henson, Bryan; Smilowitz, Laura

    2015-05-21

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersivemore »line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO?. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ?L/L« less

  5. IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 54, NO. 12, DECEMBER 2007 2261 Tissue Damage by Pulsed Electrical Stimulation

    E-Print Network [OSTI]

    Palanker, Daniel

    of the retina degenerates, yet the inner retinal neurons, the "processing circuitry" downstream from in retinal ganglion cells occurred at pulse durations near chronaxie--around 1.3 ms. Index Terms--Electrical stimulation, electroporation, neural prosthesis, neural stimulation, retinal prosthesis. I. INTRODUCTION AGE

  6. Collective inertia of Nambu-Goldstone mode from linear response theory

    E-Print Network [OSTI]

    Nobuo Hinohara

    2015-06-30

    Background: Spurious zero-energy Nambu-Goldstone (NG) modes appear when the symmetry of a system is spontaneously broken. The Thouless-Valatin inertia, the collective inertia of the NG mode, contains important information concerning collective motion. Purpose: To establish an efficient and precise method for deriving the collective inertia and the conjugate operator of a NG mode, we derive an expression for the response function in terms of the coordinate-momentum representation of the quasiparticle random-phase approximation which is valid even if a symmetry-restoring zero-energy mode is present. Methods: We use the finite amplitude method for computing the response function of superfluid nuclei with the nuclear density functional theory. Results: We derived analytically the collective inertia and the conjugate coordinate operator of the NG mode from the zero-energy linear response with the momentum operator of the NG mode. The formulation is tested in the cases of translational and pairing rotational modes. Illustrative calculations are performed for the neutron pairing rotation in Sn isotopes, the proton pairing rotation in N = 82 isotones, and the neutron and proton pairing rotations around the 130Xe nucleus. Conclusions: The proposed formulation allows us to compute the collective inertia of the NG mode precisely and efficiently. The conjugate coordinate operator can be utilized to remove spurious contributions to the strength distribution in the finite amplitude method.

  7. Mirror Modes in the Heliosheath

    SciTech Connect (OSTI)

    Tsurutani, B. T. [Jet Propulsion Lab., Calif. Inst. Tech., Pasadena, CA (United States); Guarnieri, F. L. [UNIVAP, Sao Jose dos Campos, SP (Brazil); Echer, E. E. [INPE, Sao Jose dos Campos, SP (Brazil); Lakhina, G. S. [Indian Institute of Geomagnetism, Navi Mumbai (India); Verkhoglyadova, O. P. [CSPAR, Univ. Alabama, Huntsville, AL (United States)

    2011-01-04

    Mirror mode (MM) structures are identified in the Voyager 1 heliosheath magnetic field data. Their characteristics are: (1) quasiperiodic structures with a typical scale size of {approx}57 {rho}{sub p}(proton gyroradii), (2) little or no angular changes across the structures ({approx}3 deg. longitude and {approx}3 deg. latitude), and (3) a lack of sharp boundaries at the magnetic dip edges. It is proposed that the pickup of interstellar neutrals in the upstream region of the termination shock (TS) is the likely cause of MM instability during intervals when the IMF is nearly orthogonal to the solar wind flow direction. Concomitant (quasiperpendicular) shock compression of the MM structures at the TS and additional injection of pickup ions (PUIs) throughout the heliosheath will enhance MM growth.

  8. Program steering : improving adaptability and mode selection via dynamic analysis

    E-Print Network [OSTI]

    Lin, Lee Chuan

    2004-01-01

    A multi-mode software system contains several distinct modes of operation and a controller for deciding when to switch between modes. Even when developers rigorously test a multi-mode system before deployment, they cannot ...

  9. Preference Term List

    E-Print Network [OSTI]

    Wu, Yih-Min

    · Subject Bibliography Library #12; 1/2 · Edit Preferences #12; 2/2 · Library ­ PreferencesDisplay Fields · ­ PreferencesDuplicates · ­ PreferencesFind Full Text · PreferencesReference Types #12;? #12;Journal term list() · Bibliography() · Footnotes() · #12;15 4.Journal Article "Insert Field" #12;16 5. : "Reference Types ""Insert

  10. Nonlinear pulse propagation and phase velocity of laser-driven plasma waves

    E-Print Network [OSTI]

    Schroeder, Carl B.

    2011-01-01

    of California. Nonlinear pulse propagation and phasea relativistically-intense short-pulse laser in un- derdenseinvestigated in the broad pulse limit, including the e?ects

  11. Standing-wave enhanced electroabsorption modulator for 40-GHz optical pulse generation

    E-Print Network [OSTI]

    Chou, H F; Chiu, Y J; Bowers, J E

    2003-01-01

    pulse generation, simulation, traveling-wave devices. I. IWAVE ENHANCED EAM FOR 40-GHz OPTICAL PULSE GENERATION (a) (Wave Enhanced Electroabsorption Modulator for 40-GHz Optical Pulse Generation

  12. A NEW METHOD OF PULSE-WISE SPECTRAL ANALYSIS OF GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Basak, Rupal; Rao, A. R., E-mail: rupalb@tifr.res.in, E-mail: arrao@tifr.res.in [Tata Institute of Fundamental Research, Mumbai-400005 (India)

    2013-05-10

    Time-resolved spectral analysis, though a very promising method to understand the emission mechanism of gamma-ray bursts (GRBs), is difficult to implement in practice because of poor statistics. We present a new method for pulse-wise time-resolved spectral study of the individual pulses of GRBs, using the fact that many spectral parameters are either constants or smooth functions of time. We use this method for the two pulses of GRB 081221, the brightest GRB with separable pulses. We choose, from the literature, a set of possible models that includes the Band model, blackbody with a power law (BBPL), and a collection of blackbodies with a smoothly varying temperature profile, along with a power law (mBBPL), and two blackbodies with a power law (2BBPL). First, we perform a time-resolved study to confirm the spectral parameter variations, and then we construct the new model to perform a joint spectral fit. We find that any photospheric emission in terms of blackbodies is required mainly in the rising parts of the pulses and the falling part can be adequately explained in terms of the Band model, with the low-energy photon index within the regime of synchrotron model. Interestingly, we find that 2BBPL is comparable or sometimes even better, though marginally, than the Band model, in all episodes. Consistent results are also obtained for the brightest GRB of Fermi era-GRB 090618. We point out that the method is generic enough to test any spectral model with well-defined parameter variations.

  13. Mode coupling in solar spicule oscillations

    E-Print Network [OSTI]

    Fazel, Zahra

    2015-01-01

    In a real medium which has oscillations, the perturbations can cause the energy transfer between different modes. The perturbation interpreted as an interaction between the modes is inferred as mode coupling. Mode coupling process in an inhomogeneous medium such as solar spicules may lead to the coupling of kink waves to local Alfven waves. This coupling occurs practically in any conditions when there is smooth variation in density in the radial direction. This process is seen as the decay of transverse kink waves in the medium. To study the damping of kink waves due to mode coupling, a 2.5-dimensional numerical simulation of the initial wave is considered in spicules. The initial perturbation is assumed to be in a plane perpendicular to the spicule axis. The considered kink wave is a standing wave which shows an exponential damping in the inhomogeneous layer after occurrence of the mode coupling.

  14. Mode-Wise Entanglement of Gaussian States

    E-Print Network [OSTI]

    Alonso Botero; Benni Reznik

    2003-01-16

    We address the decomposition of a multi-mode pure Gaussian state with respect to a bi-partite division of the modes. For any such division the state can always be expressed as a product state involving entangled two-mode squeezed states and single mode local states at each side. The character of entanglement of the state can therefore be understood modewise; that is, a given mode on one side is entangled with only one corresponding mode of the other, and therefore the total bi-partite entanglement is the sum of the modewise entanglement. This decomposition is generally not applicable to all mixed Gaussian states. However, the result can be extended to a special family of "isotropic" states, characterized by a phase space covariance matrix with a completely degenerate symplectic spectrum.

  15. Pressure wave charged repetitively pulsed gas laser

    DOE Patents [OSTI]

    Kulkarny, Vijay A. (Redondo Beach, CA)

    1982-01-01

    A repetitively pulsed gas laser in which a system of mechanical shutters bracketing the laser cavity manipulate pressure waves resulting from residual energy in the cavity gas following a lasing event so as to draw fresh gas into the cavity and effectively pump spent gas in a dynamic closed loop.

  16. Haykin Chapter 4 Baseband Pulse Transmission

    E-Print Network [OSTI]

    Al-Ghadhban, Samir

    1/30/2014 1 Haykin Chapter 4 Baseband Pulse Transmission EE571 Dr. Samir Alghadhban KFUPM 1 · In this chapter we study the transmission of digital data (of whatever origin) over a baseband channel. · Baseband transmission of digital data requires the use of a lowpass channel with a bandwidth large enough

  17. Ultrafast Optical Pulses: Synthesis and Applications 

    E-Print Network [OSTI]

    Wang, Kai

    2013-12-11

    scattering, which provides the required optical bandwidth. This technique is capable of producing a pulse whose duration can be shorter than one optical ?eld cycle in the visible-UV range, providing a potential for non-sinusoidal ?eld synthesis. We produce...

  18. Transient Pulse Formation in Jasmonate Signaling Pathway

    E-Print Network [OSTI]

    Subhasis Banerjee; Indrani Bose

    2010-03-03

    The jasmonate (JA) signaling pathway in plants is activated as defense response to a number of stresses like attacks by pests or pathogens and wounding by animals. Some recent experiments provide significant new knowledge on the molecular detail and connectivity of the pathway. The pathway has two major components in the form of feedback loops, one negative and the other positive. We construct a minimal mathematical model, incorporating the feedback loops, to study the dynamics of the JA signaling pathway. The model exhibits transient gene expression activity in the form of JA pulses in agreement with experimental observations. The dependence of the pulse amplitude, duration and peak time on the key parameters of the model is determined computationally. The deterministic and stochastic aspects of the pathway dynamics are investigated using both the full mathematical model as well as a reduced version of it. We also compare the mechanism of pulse formation with the known mechanisms of pulse generation in some bacterial and viral systems.

  19. TECH pulse Light stopped for a minute

    E-Print Network [OSTI]

    Rotter, Stefan

    TECH pulse · Light stopped for a minute DARMSTADT, Germany - At 186,000 miles per second, the speed of light is unparalleled, so slowing it down is a for- midable challenge - and stopping it seems impossible. But physicists in Germany report using a glasslike crystal to stop light for about one minute, which could have

  20. Pulse thermal energy transport/storage system

    DOE Patents [OSTI]

    Weislogel, Mark M. (23133 Switzer Rd., Brookpark, OH 44142)

    1992-07-07

    A pulse-thermal pump having a novel fluid flow wherein heat admitted to a closed system raises the pressure in a closed evaporator chamber while another interconnected evaporator chamber remains open. This creates a large pressure differential, and at a predetermined pressure the closed evaporator is opened and the opened evaporator is closed. This difference in pressure initiates fluid flow in the system.

  1. Proca Equation for Attosecond Electron Pulses

    E-Print Network [OSTI]

    Magdalena Pelc; Janina Marciak-Kozlowska; Miroslaw Kozlowski

    2008-03-03

    In this paper the heat transport of attosecond electron pulses is investigated. It is shown that attosecond electrons can propagate as thermal waves or diffused as particle conglommerates, Proca equation as type equation for the thermal transport of the attosecond electron pulsem is formulated

  2. Numerical Simulation of Pulse-Tube Refrigerators

    E-Print Network [OSTI]

    Tijsseling, A.S.

    . . . . . . . . . . . . . . . . . . 51 3.3.1 A model problem . . . . . . . . . . . . . . . . . 52 3.3.2 Two-grid LUGR with fixed refinement area . . . . . . . . 53 3.3.3 Two-grid LUGR with moving refinement area . . . . . . . 55 4 in fully developed pipe flow . . . . 76 5 Flow and heat transfer computations for the pulse tube 81 5.1 One

  3. Long Pulse Physics via International Stellarator Collaboration

    E-Print Network [OSTI]

    systems · Magnetic island divertor · 30 minute pulse at full power · LHD has been operating since 1998 Impurity transport studies · Island physics studies · Confinement studies at high density US XICS partnership in W7-X. #12;3D Magnetics on W7-X : Island Divertors · Exhaust heat from the W7-X plasma

  4. Ultimate Energy Densities for Electromagnetic Pulses

    E-Print Network [OSTI]

    Mankei Tsang

    2008-03-06

    The ultimate electric and magnetic energy densities that can be attained by bandlimited electromagnetic pulses in free space are calculated using an ab initio quantized treatment, and the quantum states of electromagnetic fields that achieve the ultimate energy densities are derived. The ultimate energy densities also provide an experimentally accessible metric for the degree of localization of polychromatic photons.

  5. CHARACTERIZATION OF MAGNETRON SPUTTERED COATINGS BY PULSED EDDY CURRENT TECHNIQUES

    E-Print Network [OSTI]

    Danon, Yaron

    CHARACTERIZATION OF MAGNETRON SPUTTERED COATINGS BY PULSED EDDY CURRENT TECHNIQUES Chris Mulligan1, Troy, NY 12180 ABSTRACT. A method that uses induced pulsed eddy currents for characterization of thick

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

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

    Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Wednesday, 29 November 2006 00:00 Researchers at...

  7. Place Pulse : measuring the collaborative image of the city

    E-Print Network [OSTI]

    Salesses, Mark Philip

    2012-01-01

    This thesis presents Place Pulse, a tool capable of conducting large crowdsourced visual preference surveys. The data collected with Place Pulse was used to create quantitative measures of the perceptions people hold of ...

  8. Detailed characteristics of intermittent current pulses due to positive corona

    SciTech Connect (OSTI)

    Liu, Yang, E-mail: liuyangwuh520@sina.com; Cui, Xiang; Lu, Tiebing; Wang, Zhenguo; Li, Xuebao; Xiang, Yu; Wang, Xiaobo [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China)

    2014-08-15

    In order to get detailed characteristics of intermittent current pulses due to positive corona such as the repetition rate of burst-pulse trains, the peak value ratio of the primary pulse to the secondary pulse, the number of pulses per burst, and the interval of the secondary pulses, a systematic study was carried out in a coaxial conductor-cylinder electrode system with the conductor electrode being set with a discharge point. Empirical formulae for the number of pulses per burst and the interval of the secondary pulses are first presented. A theoretical model based on the motion of the space-charge clouds is proposed. Analysis with the model gives explanations to the experimental results and reveals some new insights into the physical mechanism of positive intermittent corona.

  9. Lorentz-Dirac equation in the delta-function pulse

    E-Print Network [OSTI]

    Miroslav Pardy

    2012-08-01

    We formulate the Lorentz-Dirac equation in the plane wave and in the Dirac delta-function pulse. The discussion on the relation of the Dirac delta-function to the ultrashort laser pulse is involved.

  10. Electromagnetically induced transparency with broadband laser pulses D. D. Yavuz

    E-Print Network [OSTI]

    Yavuz, Deniz

    Electromagnetically induced transparency with broadband laser pulses D. D. Yavuz Department pulses inside an atomic medium using electromag- netically induced transparency. Extending the suggestion.65. k Over the last decade, counterintuitive optical effects using electromagnetically induced

  11. Tests of Four PT-415 Coolers Installed in the Drop-in Mode

    SciTech Connect (OSTI)

    Green, Michael A.; Wang, S.T.

    2008-07-08

    The superconducting magnets and absorbers for MICE will be cooled using PT415 pulse tube coolers. The cooler 2nd stage will be connected to magnets and the absorbers through a helium or hydrogen re-condensing system. It was proposed that the coolers be connected to the magnets in such a way that the cooler can be easily installed and removed, which permits the magnets to be shipped without the coolers. The drop-in mode requires that the cooler 1st stage be well connected to the magnet shields and leads through a low temperature drop demountable connection. The results of the PT415 drop-in cooler tests are presented.

  12. Green Bank Telescope Studies of Giant Pulses from Millisecond Pulsars

    E-Print Network [OSTI]

    H. S. Knight; M. Bailes; R. N. Manchester; S. M. Ord; B. A. Jacoby

    2005-12-13

    We have conducted a search for giant pulses from four millisecond pulsars using the 100m Green Bank Telescope. Coherently dedispersed time-series from PSR J0218+4232 were found to contain giant pulses of very short intrinsic duration whose energies follow power-law statistics. The giant pulses are in phase with the two minima of the radio integrated pulse profile but are phase aligned with the peaks of the X-ray profile. Historically, individual pulses more than 10-20 times the mean pulse energy have been deemed to be ``giant pulses''. As only 4 of the 155 pulses had energies greater than 10 times the mean pulse-energy, we argue the emission mechanism responsible for giant pulses should instead be defined through: (a) intrinsic timescales of microsecond or nanosecond duration; (b) power-law energy statistics; and (c) emission occurring in narrow phase-windows coincident with the phase windows of non-thermal X-ray emission. Four short-duration pulses with giant-pulse characteristics were also observed from PSR B1957+20. As the inferred magnetic fields at the light cylinders of the millisecond pulsars that emit giant pulses are all very high, this parameter has previously been considered to be an indicator of giant pulse emissivity. However, the frequency of giant pulse emission from PSR~B1957+20 is significantly lower than for other millisecond pulsars that have similar magnetic fields at their light cylinders. This suggests that the inferred magnetic field at the light cylinder is a poor indicator of the rate of emission of giant pulses.

  13. Ultraslow Propagation of Squeezed Vacuum Pulses with Electromagnetically Induced Transparency

    E-Print Network [OSTI]

    Daisuke Akamatsu; Yoshihiko Yokoi; Manabu Arikawa; Satoshi Nagatsuka; Takahito Tanimura; Akira Furusawa; Mikio Kozuma

    2008-01-27

    We have succeeded in observing ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Squeezed vacuum pulses (probe lights) were incident on a laser cooled 87Rb gas together with an intense coherent light (control light). A homodyne method sensitive to the vacuum state was employed for detecting the probe pulse passing through the gas. A delay of 3.1us was observed for the probe pulse having a temporal width of 10 us.

  14. Transverse oscillations in solar coronal loops induced by propagating Alfvenic pulses

    E-Print Network [OSTI]

    Luca Del Zanna; Eveline Schaekens; Marco Velli

    2004-11-24

    The propagation and the evolution of Alfvenic pulses in the solar coronal arcades is investigated by means of MHD numerical simulations. Significant transverse oscillations in coronal loops, triggered by nearby flare events, are often measured in EUV lines and are generally interpreted as standing kink modes. However, the damping times of these oscillations are typically very short (from one to a few periods) and the physical mechanism responsible for the decay is still a matter of debate. Moreover, the majority of the observed cases actually appears to be better modeled by propagating, rather than standing, modes. Here we perform 2.5-D compressible MHD simulations of impulsively generated Alfven waves propagating in a potential magnetic arcade (assumed as a simplified 2-D loop model), taking into account the stratification of the solar atmosphere with height from the photosphere to the corona. The results show a strong spreading of the initially localized pulses along the loop, due to the variations in the Alfven velocity with height, and correspondingly an efficient damping of the amplitude of the oscillations. We believe that simple explanations based on the effects of wave propagation in highly inhomogeneous media may apply to the majority of the reported cases, and that variations of the background density and Alfven speed along the loop should be considered as key ingredients in future models.

  15. Power limitations and pulse distortions in an Yb : KGW chirped-pulse amplification laser system

    SciTech Connect (OSTI)

    Kim, G H; Yang, J; Kulik, A V; Sall, E G; Chizhov, S A; Kang, U [KERI, Russia Science Seuol, 612, DMC, Hi-Tech Industry Center, 1580 Sangam-dong, Mapo-gu, 121-835 Seoul (Korea, Republic of); Yashin, V E [Federal State Unitary Enterprise ' Scientific and Industrial Corporation 'Vavilov State Optical Institute', St. Petersburg (Russian Federation)

    2013-08-31

    We have studied self-action effects (self-focusing and self-phase modulation) and stimulated Raman scattering in an Yb : KGW chirped-pulse amplification laser system. The results demonstrate that self-focusing in combination with thermal lensing may significantly limit the chirped pulse energy in this system (down to 200 ?J) even at a relatively long pulse duration (50 ps). Nonlinear lenses in the laser crystals in combination with thermal lenses bring the regenerative amplifier cavity in the laser system to the instability zone and limit the average output power at pulse repetition rates under 50 kHz. Self-phase modulation, a manifestation of self-action, may significantly distort a recompressed femtosecond pulse at energies near the self-focusing threshold. Stimulated Raman scattering in such a laser has a weaker effect on output parameters than do self-focusing and thermal lensing, and Raman spectra are only observed in the case of pulse energy instability. (nonlinear optical phenomena)

  16. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    SciTech Connect (OSTI)

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-06-16

    The paper reviews the results of vacuum arc experimental investigations made collaboratively by research groups from Berkeley and Tomsk over the last two years, i.e. since the last ISDEIV in 2006. Vacuum arc plasma of various metals was produced in pulses of a few hundred microseconds duration, and the research focussed on three topics: (i) the energy distribution functions for different ion charge states, (ii) the temporal development of the ion charge state distribution, and (iii) the evolution of the mean directed ion velocities during plasma expansion. A combined quadruple mass-to-charge and energy ana-lyzer (EQP by HIDEN Ltd) and a time-of-flight spectrometer were employed. Cross-checking data by those complimen-tary techniques helped to avoid possible pitfalls in interpre-tation. It was found that the ion energy distribution func-tions in the plasma were independent of the ion charge state, which implies that the energy distribution on a substrate are not equal to due to acceleration in the substrate's sheath. In pulsed arc mode, the individual ion charge states fractions showed changes leading to a decrease of the mean charge state toward a steady-state value. This decrease can be re-duced by lower arc current, higher pulse repetition rate and reduced length of the discharge gap. It was also found that the directed ion velocity slightly decreased as the plasma expanded into vacuum.

  17. Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Colliding Laser Pulses for Laser-Plasma Accelerator Injection Control G. R. Plateau, , C. G. R acceleration is a key challenge to achieve compact, reliable, tunable laser-plasma accelerators (LPA) [1, 2]. In colliding pulse injection the beat between multiple laser pulses can be used to control energy, energy

  18. A direct digital synthesis chirped pulse Fourier transform microwave spectrometer

    E-Print Network [OSTI]

    Blake, Geoffrey

    A direct digital synthesis chirped pulse Fourier transform microwave spectrometer Ian A. Finneran OF SCIENTIFIC INSTRUMENTS 84, 083104 (2013) A direct digital synthesis chirped pulse Fourier transform microwave pulse Fourier transform microwave (CP-FTMW) spectrometers have become the instrument of choice

  19. ACOUSTIC PULSE SPREADING IN A RANDOM FRACTAL KNUT S LNA

    E-Print Network [OSTI]

    Solna, Knut

    ACOUSTIC PULSE SPREADING IN A RANDOM FRACTAL KNUT S#28;LNA #3; Abstract. Fractal medium models are used to model for instance the heterogeneous earth and the turbulent atmosphere. A wave pulse with the medium uctuations. The modi#12;cation in the pulse shape depends on the roughness of the medium and can

  20. Pulse propagation in tapered granular chains: An analytic study

    E-Print Network [OSTI]

    Upendra Harbola; Alexandre Rosas; Massimiliano Esposito; Katja Lindenberg

    2009-05-27

    We study pulse propagation in one-dimensional tapered chains of spherical granules. Analytic results for the pulse velocity and other pulse features are obtained using a binary collision approximation. Comparisons with numerical results show that the binary collision approximation provides quantitatively accurate analytic results for these chains.

  1. Pulse: A Dynamic Deadlock Detection Mechanism Using Speculative Execution

    E-Print Network [OSTI]

    Sorin, Daniel J.

    1 Pulse: A Dynamic Deadlock Detection Mechanism Using Speculative Execution Tong Li1 , Carla S acquisitions. In this paper, we propose Pulse, a novel operating system mechanism that dynamically detects various types of deadlock in application programs. Pulse runs as a system daemon. Periodically, it scans

  2. Pulse confinement in optical fibers with random dispersion

    E-Print Network [OSTI]

    Gabitov, Ildar

    Pulse confinement in optical fibers with random dispersion M. Chertkov , I. Gabitov, and J. Moeser and eventually destroys all initially ultra-short pulses. However, under the con- straint that the integral- periodically along the fiber, the dynamics of the pulse propagation changes dramatically. For the case

  3. Asymptotic description of pulsed ultrawideband electromagnetic beam field

    E-Print Network [OSTI]

    Oughstun, Kurt

    Asymptotic description of pulsed ultrawideband electromagnetic beam field propagation in dispersive of a pulsed ultrawideband electro- magnetic beam field as it propagates through a dispersive, attenuative evolution of the pulsed-beam field through a single-contour integral that is of the same form

  4. THERMAL DIFFUSION OF HEAT PULSE IN SUBCOOLED LIQUID NITROGEN

    E-Print Network [OSTI]

    Chang, Ho-Myung

    and result in better thermal protection and faster recovery from a heat pulse. KEYWORDS: Heat TransferTHERMAL DIFFUSION OF HEAT PULSE IN SUBCOOLED LIQUID NITROGEN H. M. Chang1 , J. J. Byun1 , J. H ABSTRACT Transient heat transfer caused by a heat pulse in subcooled liquid nitrogen is investigated

  5. The Effect of Ionospheric Models on Electromagnetic Pulse Locations

    SciTech Connect (OSTI)

    Fenimore, Edward E.; Triplett, Laurie A.

    2014-07-01

    Locations of electromagnetic pulses (EMPs) determined by time-of-arrival (TOA) often have outliers with significantly larger errors than expected. In the past, these errors were thought to arise from high order terms in the Appleton-Hartree equation. We simulated 1000 events randomly spread around the Earth into a constellation of 22 GPS satellites. We used four different ionospheres: “simple” where the time delay goes as the inverse of the frequency-squared, “full Appleton-Hartree”, the “BobRD integrals” and a full raytracing code. The simple and full Appleton-Hartree ionospheres do not show outliers whereas the BobRD and raytracing do. This strongly suggests that the cause of the outliers is not additional terms in the Appleton-Hartree equation, but rather is due to the additional path length due to refraction. A method to fix the outliers is suggested based on fitting a time to the delays calculated at the 5 GPS frequencies with BobRD and simple ionospheres. The difference in time is used as a correction to the TOAs.

  6. Using X-mode L, R and O-mode reflectometry cutoffs to measure...

    Office of Scientific and Technical Information (OSTI)

    Using X-mode L, R and O-mode reflectometry cutoffs to measure scrape-off-layer density profiles for upgraded ORNL reflectometer on NSTX-U Citation Details In-Document Search Title:...

  7. B-modes and the Nature of Inflation

    E-Print Network [OSTI]

    Daniel Baumann; Daniel Green; Rafael A. Porto

    2015-12-09

    Observations of the cosmic microwave background do not yet determine whether inflation was driven by a slowly-rolling scalar field or involved another physical mechanism. In this paper we discuss the prospects of using the power spectra of scalar and tensor modes to probe the nature of inflation. We focus on the leading modification to the slow-roll dynamics, which entails a sound speed $c_s$ for the scalar fluctuations. We derive analytically a lower bound on $c_s$ in terms of a given tensor-to-scalar ratio $r$, taking into account the difference in the freeze-out times between the scalar and tensor modes. We find that any detection of primordial B-modes with $r > 0.01$ implies a lower bound on $c_s$ that is stronger than the bound derived from the absence of non-Gaussianity in the Planck data. For $r \\gtrsim 0.1$, the bound would be tantalizingly close to a critical value for the sound speed, $(c_s)_\\star = 0.47$ (corresponding to $(f_{\\rm NL}^{\\rm equil})_\\star = -0.93$), which we show serves as a threshold for non-trivial dynamics beyond slow-roll. We also discuss how an order-one level of equilateral non-Gaussianity is a natural observational target for other extensions of the canonical paradigm.

  8. New proofs for old modes Mark Wooding

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    the standard block cipher modes of operation: CBC, CFB, and OFB and analyse their security. We don't look in (full­width) CFB and OFB modes and that generalized counters encrypted using the block cipher (with Ciphertext feedback (CFB) en­ cryption 19 4.1 Description . . . . . . . . . 19 4.2 Sliding strings

  9. New proofs for old modes Mark Wooding

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    the standard block cipher modes of operation: CBC, CFB, and OFB and analyse their security. We don't look in (full-width) CFB and OFB modes and that generalized counters encrypted using the block cipher (with Ciphertext feedback (CFB) en- cryption 19 4.1 Description . . . . . . . . . 19 4.2 Sliding strings

  10. Normalizable fermion modes in a holographic superconductor

    E-Print Network [OSTI]

    Steven S. Gubser; Fabio D. Rocha; Pedro Talavera

    2009-11-18

    We consider fermions in a zero-temperature superconducting anti-de Sitter domain wall solution and find continuous bands of normal modes. These bands can be either partially filled or totally empty and gapped. We present a semi-classical argument which approximately captures the main features of the normal mode spectrum.

  11. Spatial mode properties of plasmon assisted transmission

    E-Print Network [OSTI]

    Xi-Feng Ren; Guo-Ping Guo; Yun-Feng Huang; Zhi-Wei Wang; Guang-Can Guo

    2006-09-11

    Orbital angular momentum of photons is explored to study the spatial mode properties of plasmon assisted transmission process. We found that photons carrying different orbital angular momentums have different transmission efficiencies, while the coherence between these spatial modes can be preserved.

  12. CRITERION DELINEATING THE MODE OF HEADCUT MIGRATION

    E-Print Network [OSTI]

    Julien, Pierre Y.

    CRITERION DELINEATING THE MODE OF HEADCUT MIGRATION By O. R. Stein,l Associate Member, ASCE, and P- tating headcutsthat tend to flatten as they migrate; and (2) stepped headcutsthat tend to retain nearly detachmentpotentialimmediatelyupstreamanddownstreamofthe headcutisused to delineate these modes of migration. The delineatingparameter is the ratio

  13. Mode suppression means for gyrotron cavities

    DOE Patents [OSTI]

    Chodorow, Marvin (Stanford, CA); Symons, Robert S. (Los Altos, CA)

    1983-08-09

    In a gyrotron electron tube of the gyro-klystron or gyro-monotron type, having a cavity supporting an electromagnetic mode with circular electric field, spurious resonances can occur in modes having noncircular electric field. These spurious resonances are damped and their frequencies shifted by a circular groove in the cavity parallel to the electric field.

  14. Stability and mode analysis of solar coronal loops using thermodynamic irreversible energy principles

    E-Print Network [OSTI]

    Andrea Costa; Rafael Gonzalez

    2007-06-08

    We study the modes and stability of non - isothermal coronal loop models with different intensity values of the equilibrium magnetic field. We use an energy principle obtained via non - equilibrium thermodynamic arguments. The principle is expressed in terms of Hermitian operators and allow to consider together the coupled system of equations: the balance of energy equation and the equation of motion. We determine modes characterized as long - wavelength disturbances that are present in inhomogeneous media. This character of the system introduces additional difficulties for the stability analysis because the inhomogeneous nature of the medium determines the structure of the disturbance, which is no longer sinusoidal. Moreover, another complication is that we obtain a continuous spectrum of stable modes in addition to the discrete one. We obtain a unique unstable mode with a characteristic time that is comparable with the characteristic life-time observed for loops. The feasibility of wave-based and flow-based models is examined.

  15. The Music of the Aetherwave - B-mode Polarization in Einstein-Aether Theory

    E-Print Network [OSTI]

    Masahiro Nakashima; Tsutomu Kobayashi

    2011-03-11

    We study how the dynamical vector degree of freedom in modified gravity affects the CMB B-mode polarization in terms of the Einstein-aether theory. In this theory, vector perturbations can be generated from inflation, which can grow on superhorizon scales in the subsequent epochs and thereby leaves imprints on the CMB B-mode polarization. We derive the linear perturbation equations in a covariant formalism, and compute the CMB B-mode polarization using the CAMB code modified so as to incorporate the effect of the aether vector field. We find that the amplitude of the B-mode signal from the aether field can surpass the contribution from the inflationary gravitational waves for a viable range of model parameters. We also give an analytic argument explaining the shape of the spectrum based on the tight coupling approximation.

  16. Multiple Oscillatory Modes of the Argentine Basin. Part II: The Spectral Origin of Basin Modes

    E-Print Network [OSTI]

    Weijer, Wilbert

    Multiple Oscillatory Modes of the Argentine Basin. Part II: The Spectral Origin of Basin Modes et Approches Numériques, Paris, France SARAH T. GILLE Scripps Institution of Oceanography, La Jolla In this paper the spectrum of barotropic basin modes of the Argentine Basin is shown to be connected

  17. Effects of phase and coupling between the vibrational modes on selective excitation in coherent anti-Stokes Raman scattering microscopy

    SciTech Connect (OSTI)

    Patel, Vishesha; Malinovsky, Vladimir S.; Malinovskaya, Svetlana

    2010-06-15

    Coherent anti-Stokes Raman scattering (CARS) microscopy has been a major tool of investigation of biological structures as it contains the vibrational signature of molecules. A quantum control method based on chirped pulse adiabatic passage was recently proposed for selective excitation of a predetermined vibrational mode in CARS microscopy [Malinovskaya and Malinovsky, Opt. Lett. 32, 707 (2007)]. The method utilizes the chirp sign variation at the peak pulse amplitude and gives a robust adiabatic excitation of the desired vibrational mode. Using this method, we investigate the impact of coupling between vibrational modes in molecules on controllability of excitation of the CARS signal. We analyze two models of two coupled two-level systems (TLSs) having slightly different transitional frequencies. The first model, featuring degenerate ground states of the TLSs, gives robust adiabatic excitation and maximum coherence in the resonant TLS for positive value of the chirp. In the second model, implying nondegenerate ground states in the TLSs, a population distribution is observed in both TLSs, resulting in a lack of selectivity of excitation and low coherence. It is shown that the relative phase and coupling between the TLSs play an important role in optimizing coherence in the desired vibrational mode and suppressing unwanted transitions in CARS microscopy.

  18. Parafermionic zero modes in ultracold bosonic systems

    E-Print Network [OSTI]

    Mohammad F. Maghrebi; Sriram Ganeshan; David J. Clarke; Alexey V. Gorshkov; Jay D. Sau

    2015-04-20

    Exotic topologically protected zero modes with parafermionic statistics (also called fractionalized Majorana modes) have been proposed to emerge in devices fabricated from a fractional quantum Hall system and a superconductor. The fractionalized statistics of these modes takes them an important step beyond the simplest non-Abelian anyons, Majorana fermions. Building on recent advances towards the realization of fractional quantum Hall states of bosonic ultracold atoms, we propose a realization of parafermions in a system consisting of Bose-Einstein-condensate trenches within a bosonic fractional quantum Hall state. We show that parafermionic zero modes emerge at the endpoints of the trenches and give rise to a topologically protected degeneracy. We also discuss methods for preparing and detecting these modes.

  19. Sliding mode control of quantum systems

    E-Print Network [OSTI]

    Daoyi Dong; Ian R. Petersen

    2009-10-31

    This paper proposes a new robust control method for quantum systems with uncertainties involving sliding mode control (SMC). Sliding mode control is a widely used approach in classical control theory and industrial applications. We show that SMC is also a useful method for robust control of quantum systems. In this paper, we define two specific classes of sliding modes (i.e., eigenstates and state subspaces) and propose two novel methods combining unitary control and periodic projective measurements for the design of quantum sliding mode control systems. Two examples including a two-level system and a three-level system are presented to demonstrate the proposed SMC method. One of main features of the proposed method is that the designed control laws can guarantee desired control performance in the presence of uncertainties in the system Hamiltonian. This sliding mode control approach provides a useful control theoretic tool for robust quantum information processing with uncertainties.

  20. Long-Term Risk From Actinides in the Environment: Modes of Mobility

    SciTech Connect (OSTI)

    Shawki Ibrahim, Ph.D.

    2001-05-24

    Laboratory soil column experiments were conducted to investigate the migration of plutonium in soils from the Waste Isolation Pilot Plant (WIPP) and the Rocky Flats Environmental Technology Site.

  1. Performance Assessment of Single Electrode-Supported Solid Oxide Cells Operating in the Steam Electrolysis Mode

    SciTech Connect (OSTI)

    X. Zhang; J. E. O'Brien; R. C. O'Brien; N. Petigny

    2011-11-01

    An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. Results presented in this paper were obtained from single cells, with an active area of 16 cm{sup 2} per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes ({approx}10 {mu}m thick), nickel-YSZ steam/hydrogen electrodes ({approx}1400 {mu}m thick), and modified LSM or LSCF air-side electrodes ({approx}90 {mu}m thick). The purpose of the present study is to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of voltage-current (VI) sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-term testing, first in the fuel cell mode, then in the electrolysis mode. Results generally indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of an improved single-cell test apparatus developed specifically for these experiments.

  2. The performance of PEM fuel cells fed with oxygen through the free-convection mode

    E-Print Network [OSTI]

    The performance of PEM fuel cells fed with oxygen through the free-convection mode Pei-Wen Li; accepted 27 September 2002 Abstract The feasibility and restrictions of feeding oxygen to a PEM fuel cell at the cathode surface, which can be viewed in terms of the relationship of the fuel cell current density

  3. The Normal Modes of the Earth Lapo Boschi (lapo@erdw.ethz.ch)

    E-Print Network [OSTI]

    Boschi, Lapo

    ) is given by Newton's law of gravitation, ¨u(r, t) = V r - r |r - r|3 G(r )d3 r , (1) with G denoting Newton, with associated eigenfrequencies: the normal modes (free oscillations) of the Earth. Self-Gravitation to the gravity field caused by the Earth's deformation u(r, t) itself ("self-gravitation"). Those terms, how

  4. Solitary electromechanical pulses in Lobster neurons

    E-Print Network [OSTI]

    Gonzalez-Perez, Alfredo; Budvytyte, Rima; Villagran-Vargas, Edgar; Jackson, Andrew D; Heimburg, Thomas

    2015-01-01

    Investigations of nerve activity have focused predominantly on electrical phenomena. Nerves, however, are thermodynamic systems, and changes in temperature and in the dimensions of the nerve can also be observed during the action potential. Measurements of heat changes during the action potential suggest that the nerve pulse shares many characteristics with an adiabatic pulse. In the past, experiments by Iwasa & Tasaki demonstrated small changes in nerve thickness and length during the action potential. Such findings have led to the suggestion that the action potential may be related to electromechanical solitons traveling without dissipation. Here, we present ultrasensitive AFM recordings of mechanical changes on the order of 0.2 - 1.2 nm in the giant axons of the lobster. When stimulated at opposite ends of the same axon, colliding action potentials pass through one another and do not annihilate. These observations are consistent with a mechanical interpretation of the nervous impulse.

  5. Electromagnetic Pulse from Final Gravitational Stellar Collapse

    E-Print Network [OSTI]

    P. D. Morley; Ivan Schmidt

    2002-01-30

    We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for medium size cores undergoing hydrodynamic bounce and large size cores undergoing black hole formation. We clearly show that there must exist two classes of neutron stars, separated by maximum allowable masses: those that collapsed as solitary stars (dynamical mass limit) and those that collapsed in binary systems allowing mass accretion (static neutron star mass). Our results show that the electromagnetic pulse spectrum associated with black hole formation is a universal signature, independent of the nuclear EOS. Our results also predict that there must exist black holes whose masses are less than the static neutron star stability limit.

  6. Combining attosecond XUV pulses with coincidence spectroscopy

    SciTech Connect (OSTI)

    Sabbar, M. Heuser, S.; Boge, R.; Lucchini, M.; Cirelli, C.; Keller, U.; Gallmann, L.

    2014-10-15

    Here we present a successful combination of an attosecond beamline with a COLTRIMS apparatus, which we refer to as AttoCOLTRIMS. The setup provides either single attosecond pulses or attosecond pulse trains for extreme ultraviolet-infrared pump-probe experiments. We achieve full attosecond stability by using an active interferometer stabilization. The capability of the setup is demonstrated by means of two measurements, which lie at the heart of the COLTRIMS detector: firstly, we resolve the rotating electric field vector of an elliptically polarized few-cycle infrared laser field by attosecond streaking exploiting the access to the 3D momentum space of the charged particles. Secondly, we show streaking measurements on different atomic species obtained simultaneously in a single measurement making use of the advantage of measuring ions and electrons in coincidence. Both of these studies demonstrate the potential of the AttoCOLTRIMS for attosecond science.

  7. Ultrashort pulse amplification in cryogenically cooled amplifiers

    DOE Patents [OSTI]

    Backus, Sterling J.; Kapteyn, Henry C.; Murnane, Margaret Mary

    2004-10-12

    A laser amplifier system amplifies pulses in a single "stage" from .about.10.sup.-9 joules to more than 10.sup.-3 joules, with average power of 1-10 watts, and beam quality M.sup.2 <2. The laser medium is cooled substantially below room temperature, as a means to improve the optical and thermal characteristics of the medium. This is done with the medium inside a sealed, evacuated or purged cell to avoid moisture or other materials condensing on the surface. A "seed" pulse from a separate laser is passed through the laser medium, one or more times, in any of a variety of configurations including single-pass, multiple-pass, and regenerative amplifier configurations.

  8. Global synchronization of parallel processors using clock pulse width modulation

    DOE Patents [OSTI]

    Chen, Dong; Ellavsky, Matthew R.; Franke, Ross L.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Jeanson, Mark J.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Littrell, Daniel; Ohmacht, Martin; Reed, Don D.; Schenck, Brandon E.; Swetz, Richard A.

    2013-04-02

    A circuit generates a global clock signal with a pulse width modification to synchronize processors in a parallel computing system. The circuit may include a hardware module and a clock splitter. The hardware module may generate a clock signal and performs a pulse width modification on the clock signal. The pulse width modification changes a pulse width within a clock period in the clock signal. The clock splitter may distribute the pulse width modified clock signal to a plurality of processors in the parallel computing system.

  9. Fast gates for ion traps by splitting laser pulses

    E-Print Network [OSTI]

    C. D. B. Bentley; A. R. R. Carvalho; D. Kielpinski; J. J. Hope

    2013-04-09

    We present a fast phase gate scheme that is experimentally achievable and has an operation time more than two orders of magnitude faster than current experimental schemes for low numbers of pulses. The gate time improves with the number of pulses following an inverse power law. Unlike implemented schemes which excite precise motional sidebands, thus limiting the gate timescale, our scheme excites multiple motional states using discrete ultra-fast pulses. We use beam-splitters to divide pulses into smaller components to overcome limitations due to the finite laser pulse repetition rate. This provides gate times faster than proposed theoretical schemes when we optimise a practical setup.

  10. Status Company Terminal Term

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2,BL4-2 Bio-SAXSAppropriations CommitteeShort-Term

  11. Terms and Conditions

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired Solar FuelTechnologyTel: Name: Rm. Tel: Location: Rm.TennesseeTerms and

  12. GENERAL TERMS & CONDITIONS

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HABFESOpportunities Nuclear Physics (NP)aboutRioGlobalGENERAL TERMS

  13. Carbon-14 Bomb-Pulse Dating

    SciTech Connect (OSTI)

    Buchholz, B A

    2007-12-16

    Atmospheric testing of nuclear weapons during the 1950s and early 1960s doubled the concentration of carbon-14 atmosphere and created a pulse that labeled everything alive in the past 50 years as carbon moved up the food chain. The variation in carbon-14 concentration in time is well-documented and can be used to chronologically date all biological materials since the mid-1950s.

  14. The Homopolar Pulse Billet Heating Process 

    E-Print Network [OSTI]

    Keith, R. E.; Weldon, W. F.

    1982-01-01

    ., Rylander, H. G., and Woodson, H. H., "Feasibility Study of Pipe Welding ~'- "Inertial Energy Storage Research at Using a Homopolar Generator", Electric The University of Texas at Austin", Power Research Institute Rept. No. IEEE Int'l. Pulsed Power Conf... and Design, Fabrication, and Testing of a Topological Considerations for Fast Five Megajoule Homopolar Discharge Homopolar Machines", IEEE Motor-Generator", Int'l. Conf. on Int'l. Conf. on Plasma Science, Ann Energy Storage, Comp~ession, and Arbor, MI...

  15. Pulsed atmospheric fluidized bed combustor apparatus

    DOE Patents [OSTI]

    Mansour, Momtaz N. (Columbia, MD)

    1993-10-26

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

  16. Gravitational-wave modes from precessing black-hole binaries

    E-Print Network [OSTI]

    Michael Boyle; Lawrence E. Kidder; Serguei Ossokine; Harald P. Pfeiffer

    2014-09-22

    Gravitational waves from precessing black-hole binaries exhibit features that are absent in nonprecessing systems. The most prominent of these is a parity-violating asymmetry that beams energy and linear momentum preferentially along or opposite to the orbital angular momentum, leading to recoil of the binary. The asymmetry will appear as amplitude and phase modulations at the orbital frequency. For strongly precessing systems, it accounts for at least 3% amplitude modulation for binaries in the sensitivity band of ground-based gravitational-wave detectors, and can exceed 50% for massive systems. Such asymmetric features are also clearly visible when the waves are decomposed into modes of spin-weighted spherical harmonics, and are inherent in the waves themselves---rather than resulting from residual eccentricity in numerical simulations, or from mode-mixing due to precession. In particular, there is generically no instantaneous frame for which the mode decomposition will have any symmetry. We introduce a method to simplify the expressions for waveforms given in analytical relativity, which can be used to combine existing high-order waveforms for nonprecessing systems with expressions for the precessing contributions, leading to improved accuracy and a unified treatment of precessing and nonprecessing binaries. Using this method, it is possible to clarify the nature and the origins of the asymmetries and show the effects of asymmetry on recoils more clearly. We present post-Newtonian (PN) expressions for the waveform modes that include these terms, complete to the relative 2PN level in spin (proportional to $v^4/c^4$ times a certain combination of the spins). Comparing the results of those expressions to numerical results, we find good qualitative agreement. We also demonstrate how these expressions can be used to efficiently calculate waveforms for gravitational-wave astronomy.

  17. Collective modes and thermodynamics of the liquid state

    E-Print Network [OSTI]

    K. Trachenko; V. V. Brazhkin

    2015-12-21

    Strongly interacting, dynamically disordered and with no small parameter, liquids took a theoretical status between gases and solids. We review different approaches to liquids and propose that liquids do not need classifying in terms of their proximity to gases and solids. Instead, they are a unique system in their own class with a notably mixed dynamical state in contrast to pure dynamical states of solids and gases. We start with explaining how the first-principles approach to liquids is an intractable, exponentially complex problem of coupled non-linear oscillators with bifurcations. This is followed by a reduction of the problem based on liquid relaxation time $\\tau$ representing non-perturbative treatment of strong interactions. On the basis of $\\tau$, solid-like high-frequency modes are predicted and we review related recent experiments. We demonstrate how these modes can be derived by generalizing either hydrodynamic or elasticity equations. We comment on the historical trend to approach liquids using hydrodynamics and compare it to an alternative solid-like approach. We subsequently discuss how collective modes evolve with temperature and how this affects liquid energy and other properties such as fast sound. Here, our emphasis is on real, rather than model, liquids. Highlighting the dominant role of high-frequency modes for liquid energy, we review a wide range of liquids: subcritical low-viscous liquids, supercritical state with two different dynamical and thermodynamic regimes separated by the Frenkel line, highly-viscous liquids and liquid-glass transition. We also discuss liquid-liquid phase transitions where the solid-like properties of liquids have become further apparent. We then discuss gas-like and solid-like approaches to quantum liquids and persisting theoretical problems. We list areas where interesting insights may appear and continue the extraordinary liquid story.

  18. Slagging retrofit pulsed coal combustor: Final report

    SciTech Connect (OSTI)

    Not Available

    1987-01-01

    A concept for a novel form of slagging retrofit pulsed coal combustor was tested in the laboratory. The combustor is based on controlled use of a form of high pressure amplitude combustion instability. The approach adopted was to resolve, in single pulse experiments, the basic technical issues arising in the development of the combustor. In a cold flow device, the issues of coal spatial distribution were addressed and a combustor and solids disperser configuration was developed to give uniform coal distribution in the combustor. Single pulse ignition experiments were conducted to determine the pressure rise in combustor, pressure rise-decay times, and coal conversion a function of various operating variables. Coal injection, flame propagation, and blowdown times leading to potential combustor size reduction of three times over steady flow combustors were demonstrated. The results give high pressure exhaust leading to potentially improved downstream heat transfer and reduced boiler size. Finally, zero-, one-, and two-dimensional mathematical models were developed in support of the experiments and also to provide design capability. 11 refs., 43 figs.

  19. New organic crystals for pulse shape discrimination

    SciTech Connect (OSTI)

    Hull, G; Zaitseva, N; Cherepy, N; Newby, J; Stoeffl, W; Payne, S

    2008-07-16

    Efficient, readily-available, low-cost, high-energy neutron detectors can play a central role in detecting illicit nuclear weapons since neutrons are a strong indication for the presence of fissile material such as Plutonium and Highly-Enriched Uranium. The main challenge in detecting fast neutrons consists in the discrimination of the signal from the gamma radiation background. At present, the only well-investigated organic crystal scintillator for fast neutron detection, in a n/{gamma} mixed field, is stilbene, which while offering good pulse shape discrimination, is not widely used because of its limited availability and high cost. In this work we report the results of our studies made with a number of new organic crystals, which exhibit pulse shape discrimination for detection of fast neutrons. In particular 1,1,4,4-tetraphenyl-1,3-butadiene features a light yield higher than anthracene and a Figure of Merit (FOM) for the pulse shape discrimination better than stilbene. New crystals are good candidates for the low-cost solution growth method, thus representing promising organic scintillators for widespread deployment for high-energy neutron detection.

  20. REX, a 5-MV pulsed-power source for driving high-brightness electron beam diodes

    SciTech Connect (OSTI)

    Carlson, R.L.; Kauppila, T.J.; Ridlon, R.N.

    1991-01-01

    The Relativistic Electron-beam Experiment, or REX accelerator, is a pulsed-power source capable of driving a 100-ohm load at 5 MV, 50 kA, 45 ns (FWHM) with less than a 10-ns rise and 15-ns fall time. This paper describes the pulsed-power modifications, modelling, and extensive measurements on REX to allow it to drive high impedance (100s of ohms) diode loads with a shaped voltage pulse. A major component of REX is the 1.83-m-diam {times} 25.4-cm-thick Lucite insulator with embedded grading rings that separates the output oil transmission line from the vacuum vessel that contains the re-entrant anode and cathode assemblies. A radially tailored, liquid-based resistor provides a stiff voltage source that is insensitive to small variations of the diode current and, in addition, optimizes the electric field stress across the vacuum side of the insulator. The high-current operation of REX employs both multichannel peaking and point-plane diverter switches. This mode reduces the prepulse to less than 2 kV and the postpulse to less than 5% of the energy delivered to the load. Pulse shaping for the present diode load is done through two L-C transmission line filters and a tapered, glycol-based line adjacent to the water PFL and output switch. This has allowed REX to drive a diode producing a 4-MV, 4.5-kA, 55-ns flat-top electron beam with a normalized Lapostolle emittance of 0.96 mm-rad corresponding to a beam brightness in excess of 4.4 {times} 10{sup 8} A/m{sup 2} {minus}rad{sup 2}. 6 refs., 13 figs.