Sample records for term pulse mode

  1. Single mode pulsed dye laser oscillator

    DOE Patents [OSTI]

    Hackel, Richard P. (Livermore, CA)

    1992-01-01T23:59:59.000Z

    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. Single mode pulsed dye laser oscillator

    DOE Patents [OSTI]

    Hackel, R.P.

    1992-11-24T23:59:59.000Z

    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. 6 figs.

  3. 1966 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 15, NO. 10, OCTOBER 1997 Mode Conversion of Ultrafast Pulses by Grating

    E-Print Network [OSTI]

    Ziolkowski, Richard W.

    conversion of an ultrafast, ultrawide-bandwidth optical pulse propagating in a layered di- electric waveguide for an ultrafast six-cycle optical pulse over that achieved with standard uniform grating convertors. Index Terms--Dielectric waveguides, FDTD, mode conversion, mode extraction, numerical modeling, ultrafast optical pulses. I

  4. March 15, 2000 / Vol. 25, No. 6 / OPTICS LETTERS 423 Generation of 90-fs pulses from a mode-locked diode-pumped

    E-Print Network [OSTI]

    Boyer, Edmond

    with a crystalline host. This laser is mode locked with a high-finesse semiconductor saturable-absorber mirror with the capability to bridge the gap in terms of pulse dura- tion, on the one hand, and emission cross sections

  5. Control and generation of localized pulses in passively mode-locked semiconductor lasers

    E-Print Network [OSTI]

    Marconi, M; Camelin, P; Chaparro, D; Balle, S; Giudici, M

    2015-01-01T23:59:59.000Z

    We show experimentally and theoretically that localized pulses can be generated from an electrically biased $200\\,\\mu$m multi-transverse mode Vertical-Cavity Surface-Emitting Laser. The device is passively mode-locked using optical feedback from a distant Resonant Saturable Absorber Mirror and it is operated below threshold. We observe multistability between the off solution and a large variety of pulsating solutions with different number and arrangements of pulses per round-trip, thus indicating that the mode-locked pulses are localized, i.e. mutually independent. We show that a modulation of the bias current allows controlling the number of the pulses travelling within the cavity, thus suggesting that our system can be operated as an arbitrary pattern generator of 10 ps pulses and 1 W peak power.

  6. Synchronization of InP Colliding Pulse Mode Locked Laser by Electrical Subharmonic Modulation

    E-Print Network [OSTI]

    Kolner, Brian H.

    to an InP-InGaAsP wafer. The CPM laser includes a saturable absorber (SA) placed in the middle of the laser-short pulses without self- pulsing commonly seen in regular mode locked lasers [1-2,4]. The MOCVD grown InP-InGaAsP deeper into absorption saturation for more stable and effective pulse-shaping for generating ultra

  7. All-Fiber Pulsed Lasers Passively Mode-Locked by Transferable Vertically Aligned Carbon Nanotube Film

    E-Print Network [OSTI]

    Maruyama, Shigeo

    All-Fiber Pulsed Lasers Passively Mode-Locked by Transferable Vertically Aligned Carbon Nanotube of Tokyo, Tokyo 113-8656, Japan An all-fiber passive laser mode locking is realized with a vertically aligned single-walled carbon nanotube film that can be transferred onto an arbitrary substrate using only

  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

    2015-01-01T23:59:59.000Z

    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. Pulsed single-mode dye laser for coherent control experiments John D. Corless, James A. West, Jake Bromage, and C. R. Stroud, Jr.

    E-Print Network [OSTI]

    Stroud Jr., Carlos R.

    Pulsed single-mode dye laser for coherent control experiments John D. Corless, James A. West, Jake Received 27 January 1997; accepted for publication 20 March 1997 We describe a pulsed single-mode dye laser quality parameter M2 1.2. We modified the pulse shape using saturable absorption in the dye amplifier

  10. Role of locked mode in the effectiveness of pulsed poloidal current drive regime in the reversed-field pinch

    SciTech Connect (OSTI)

    Frassinetti, L.; Yagi, Y.; Koguchi, H.; Shimada, T.; Hirano, Y.; Sakakita, H. [National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2005-10-01T23:59:59.000Z

    The close relationship between the locked mode (LM) and pulsed poloidal current drive (PPCD) regime in a reversed-field pinch device is described. If the modes lock close to the shell gap then the LM is enhanced and there is a high probability that the PPCD will not improve plasma performance. The physical reason will be discussed. If the position of the locked mode is far from the shell gap then the PPCD is effective with a high probability. LM energy is reduced and the more the LM energy decreases, the better the plasma performance.

  11. Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma

    SciTech Connect (OSTI)

    Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)

    2014-06-15T23:59:59.000Z

    A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

  12. Long-term stable timing distribution of an ultrafast optical pulse train over multiple fiber links with polarization maintaining output

    E-Print Network [OSTI]

    Cox, Jonathan A.

    The distribution of an ultrafast optical pulse train over multiple fiber links with long-term stable timing precision within 2 femtoseconds rms is accomplished by integrating a polarization maintaining output with 300 meter ...

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

    SciTech Connect (OSTI)

    Kwon, H. C. [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of) [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Research and Development Division, SK Hynix Semiconductor Inc., Icheon 467-701 (Korea, Republic of); Jung, S. Y. [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of)] [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Kim, H. Y.; Won, I. H.; Lee, J. K., E-mail: jkl@postech.ac.kr [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-03-15T23:59:59.000Z

    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.

  14. 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.

    1993-04-01T23:59:59.000Z

    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.

  15. Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes

    SciTech Connect (OSTI)

    Dr. Anatoly Shteynberg, PhD

    2006-08-17T23:59:59.000Z

    This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

  16. Final Technical Progress Report Long term risk from actinides in the environment: Modes of mobility

    SciTech Connect (OSTI)

    Thomas B. Kirchner

    2002-03-22T23:59:59.000Z

    The key source of uncertainty in assessing actinide mobility is the relative importance of transport by: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depends on several environmental factors and they compete with one another. A scientific assessment of the long-term risks associated with actinides in surface soils depends on better quantifying each of these three modes of mobility. The objective from our EMSP study was to quantify the mobility of soil actinides by wind erosion, water erosion, and vertical migration at three semiarid sites where actinide mobility is a key technical, social and legal issue. This EMSP project was the first to evaluate all three factors at a site. The approach has been to investigate both short- and long-term issues based on field and lab studies and model comparisons. Our results demonstrate the importance of incorporating threshold responses into a modeling framework that accounts for environmental factors and natural disturbances that trigger large changes in actinide mobility. The study measured erosional losses of sediment and fallout cesium (an actinide analogue) from field plots located near WIPP in 1998. The results highlight the large effect of burning as a disturbance on contaminant transport and mobility via runoff and erosion. The results show that runoff, erosion, and actinide transport are (1) strongly site specific-differences in radionuclide transport between WIPP and Rocky Flats differed by a factor of twelve because of soil and vegetation differences, and (2) are strongly impacted by disturbances such as fire, which can increase runoff, erosion, and actinide transport by more than an order of magnitude. In addition, a laboratory experiment using soil columns was conducted to investigate the vertical transport of contaminants in sandy soils. Nine columns of soil collected from the vicinity of the WIPP site were prepared. The column consisted of a piece of PVC pipe 20 cm in diameter and approximately 22 cm long. A thin ''marker layer'' of white soil was added to the top of each column followed by a thin layer of soil that had been spiked with 137Cs, cerium and lanthanum was applied to the surface. Approximately 900 cm of water (the equivalent of about 30 years of rainfall) was then applied at a rate of 3.2 L d-1. All of the activity contained in the soil core appeared to be in the top few mm of soil, i.e. there was virtually no movement of the 134Cs labeled particles. Finally, a library of object-oriented model components was created using Visual Basic to support the construction of contaminant transport models. These components greatly simplify the task of building 1- to 3- dimensional simulation models for risk assessment. The model components created under this funding were subsequently applied to help answer questions regarding risks from irrigation associated with potential releases from the Yucca Mountain waste repository.

  17. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    E-Print Network [OSTI]

    Kreslo, I; Delaquis, S; Ereditato, A; Janos, S; Messina, M; Moser, U; Rossi, B; Zeller, M

    2011-01-01T23:59:59.000Z

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.

  18. Pulse-shape discrimination of scintillation from alpha and beta particles with liquid scintillator and Geiger-mode multipixel avalanche diodes

    E-Print Network [OSTI]

    I. Kreslo; I. Badhrees; S. Delaquis; A. Ereditato; S. Janos; M. Messina; U. Moser; B. Rossi; M. Zeller

    2011-06-23T23:59:59.000Z

    A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.

  19. 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

    2011-11-01T23:59:59.000Z

    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.

  20. Long-term risk from actinides in the environment: Modes of mobility. 1998 annual progress report

    SciTech Connect (OSTI)

    Breshears, D.D.; Whicker, J.J. [Los Alamos National Lab., NM (US); Ibrahim, S.A.; Whicker, F.W.; Hakonson, T.E. [Colorado State Univ., Fort Collins, CO (US); Kirchner, T. [New Mexico State Univ., Las Cruces, NM (US)

    1998-06-01T23:59:59.000Z

    'The mobility of actinides in surface soils is a key issue of concern at several DOE facilities in arid and semiarid environments, including Rocky Flats, Hanford, Nevada Test Site, Idaho National Engineering Laboratory, and Los Alamos National Laboratory and the Waste Isolation Pilot Plant (WIPP). Key sources of uncertainty in assessing Pu mobility are the magnitudes of mobility resulting from three modes of transport: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depend on numerous environmental factors and they compete with one another, particularly for actinides in very shallow soils ({approximately} 1 \\265m). The overall goal of the study is to quantify the mobility of soil actinides from all three modes. The authors study is using field measurements, laboratory experiments, and ecological modeling to address these three processes at three DOE facilities where actinide kinetics are of concern: WIPP, Rocky Flats, and Hanford. Wind erosion is being measured with suite of monitoring equipment, water erosion is being studied with rainfall simulation experiments, vertical migration is being studied in controlled laboratory experiments, and the three processes are being integrated using ecological modeling. Estimates for clean up of soil actinides for the extensive tracts of DOE land range to hundreds of billion $ in the US Without studies of these processes, unnecessary clean-up of these areas may waste billions of dollars and cause irreparable ecological damage through the soil removal. Further, the outcomes of litigation against DOE are dependent on quantifying the mobility of actinides in surface soils. This report provides a summary of work for the first year of a 3-year project; subcontracts to collaborating institutions (Colorado State University and New Mexico State University) were not in place until late December 1997, and hence this report focuses on the results of the 5 months from January through May 1998. The major result to date is a review of literature on the potential for using soil concentrations of {sup 137}Cs and {sup 241}Am as tracers for plutonium in soil. Measurements of {sup 239}Pu contamination in the environment are expensive and time consuming, requiring radiochemical analysis and alpha spectroscopy. They evaluated the literature for measurements of {sup 137}Cs and {sup 241}Am, both of which are more cost-effectively measured by gamma spectrometry, as tracers for Pu in soil. Their results indicate that: significant positive correlation exists between Pu, Cs, and Am in soils and sediments at several locations including Rocky Flats, Los Alamos, and Hanford; atmospheric transport of Pu and Cs from worldwide fallout is essentially the same; the attachment of Pu and Cs to soil particles of various size is very similar; both Pu and Cs movement in the environment correlate well with soil and sediment particle movements; a significant correlation between Pu, Cs, and Am was found in soil as a function of depth, indicating similar vertical migration behavior (most of the activity of these radionuclides is confined to the top 10--20 cm of soil at virtually all locations); most Pu and Cs are strongly absorbed onto clay and organic matter in soils and there is essentially very little leaching of Pu, Am and Cs through soil columns. Based on the above information, they believe that {sup 137}Cs and {sup 241}Am are excellent tracers for both {sup 239}Pu and soil particle transport processes in clay, mineral bearing and/or organic soils. Therefore, Cs and Am would be good tracers for the proposed water erosion and vertical migration work, at least for both Rocky Flats and Hanford. The correlation between Pu and Cs may not be as strong in sandy soil (e.g. WIPP site), however, examination of more data is needed.'

  1. Nerve-pulse interactions

    SciTech Connect (OSTI)

    Scott, A.C.

    1982-01-01T23:59:59.000Z

    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.

  2. Stabilized Ultrafast Pulse Generation and Optical Frequency Combs Techniques

    E-Print Network [OSTI]

    Van Stryland, Eric

    Stabilized Ultrafast Pulse Generation and Optical Frequency Combs ­ Techniques and Applications Diodes ­ Review Ultrafast Dynamics ­ Breathing Mode (Dispersion Managed Cavity) · High Pulse Energy to Make Short Pulses - Review Ultrafast Dynamics- - Dispersion Managed (Breathing Mode) MLL #12

  3. 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

  4. 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

    2007-02-20T23:59:59.000Z

    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.

  5. 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.

    -cavity synchronously mode-locked dye laser 0. Buccafusca, J. J. Rocca, M. C. Marconi, and C. S. Menoni National Science-cavity synchronously pumped dye laser containing a mixture of two dyes in a single jet and intracavity spatial masking for frequency selection. The utilization of this dual wavelength dye laser to monitor the relaxation

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

    DOE Patents [OSTI]

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

    2003-09-16T23:59:59.000Z

    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.

  7. 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, E-mail: leeli@mail.hust.edu.cn; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, HuaZhong University of Science and Technology (HUST), Wuhan 430074 (China)

    2014-01-14T23:59:59.000Z

    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.

  8. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, H.A. Jr.

    1984-01-01T23:59:59.000Z

    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.

  9. Pulsed-neutron monochromator

    DOE Patents [OSTI]

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

    1985-01-01T23:59:59.000Z

    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.

  10. Low-noise pulse conditioner

    DOE Patents [OSTI]

    Bird, David A. (Oak Ridge, TN)

    1983-01-01T23:59:59.000Z

    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.

  11. Pulse transmission transceiver architecture for low power communications

    DOE Patents [OSTI]

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

    2003-08-05T23:59:59.000Z

    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.

  12. Single-cycle radio-frequency pulse generation by an optoelectronic

    E-Print Network [OSTI]

    Horowitz, Moshe

    Single-cycle radio-frequency pulse generation by an optoelectronic oscillator Etgar C. Levy,1-locking of an optoelectronic oscillator which generates a single-cycle radio-frequency pulse train. The measured pulse to pulse by a passive mode-locked oscillator. The passive mode-locked optoelectronic oscillator is important

  13. Method to calibrate fission chambers in Campbelling mode

    SciTech Connect (OSTI)

    Benoit Geslot; Troy C. Unruh; Philippe Filliatre; Christian Jammes; Jacques Di Salvo; Stéphane Bréaud; Jean-François Villard

    2011-06-01T23:59:59.000Z

    Fission chambers are neutron detectors which are widely used to instrument experimental reactors such as material testing reactors or zero power reactors. In the presence of a high level mixed gamma and neutron flux, fission chambers can be operated in Campbelling mode (also known as 'fluctuation mode' or 'mean square voltage mode') to provide reliable and precise neutron related measurements. Fission chamber calibration in Campbelling mode (in terms of neutron flux) is usually done empirically using a calibrated reference detector. A major drawback of this method is that calibration measurements have to be performed in a neutron environment very similar to the one in which the calibrated detector will be used afterwards. What we propose here is a different approach based on characterizing the fission chamber response in terms of fission rate. This way, the detector calibration coefficient is independent from the neutron spectrum and can be determined prior to the experiment. The fissile deposit response to the neutron spectrum can then be assessed independently by other means (experimental or numerical). In this paper, the response of CEA made miniature fission chambers in Campbelling mode is studied. We use a theoretical model of the signal to calculate the calibration coefficient. Input parameters of the model come from statistical distribution of individual pulses. Supporting measurements have been made in the CEA Cadarache zero power reactor MINERVE. Results are compared to an empirical Campbelling mode calibration.

  14. Pulse stretcher

    DOE Patents [OSTI]

    Horton, James A. (Livermore, CA)

    1994-01-01T23:59:59.000Z

    Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

  15. Broadband laser cooling of trapped atoms with ultrafast pulses

    E-Print Network [OSTI]

    Blinov, Boris

    Broadband laser cooling of trapped atoms with ultrafast pulses B. B. Blinov,* R. N. Kohn, Jr., M. J ions in an rf trap using ultrafast pulses from a mode-locked laser. The temperature of a single ion On the other hand, an ultrafast laser whose pulse is a few picoseconds long will naturally have a bandwidth

  16. System and process for pulsed multiple reaction monitoring

    DOE Patents [OSTI]

    Belov, Mikhail E

    2013-05-17T23:59:59.000Z

    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.

  17. 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)

    1996-12-30T23:59:59.000Z

    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.

  18. Pulsed hydrojet

    DOE Patents [OSTI]

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

    1986-06-10T23:59:59.000Z

    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.

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

    DOE Patents [OSTI]

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

    2003-08-12T23:59:59.000Z

    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.

  20. Note: Emittance measurements of intense pulsed proton beam for different pulse length and repetition rate

    SciTech Connect (OSTI)

    Miracoli, R. [ESS Bilbao, Vizcaya (Spain); INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Gammino, S.; Celona, L.; Mascali, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Castro, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); Gobin, R.; Delferriere, O.; Adroit, G.; Senee, F. [CEA-IRFU, Gif sur Yvette Cedex (France); Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNAO, Str. Pr. Campeggi, Pavia (Italy)

    2012-05-15T23:59:59.000Z

    The high intensity ion source (SILHI), in operation at CEA-Saclay, has been used to produce a 90 mA pulsed proton beam with pulse length and repetition rates suitable for the European Spallation Source (ESS) linac. Typical r-r{sup '} rms normalized emittance values smaller than 0.2{pi} mm mrad have been measured for operation in pulsed mode (0.01 < duty cycle < 0.15 and 1 ms < pulse duration < 10 ms) that are relevant for the design update of the Linac to be used at the ESS in Lund.

  1. Tapered pulse tube for pulse tube refrigerators

    DOE Patents [OSTI]

    Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)

    1999-01-01T23:59:59.000Z

    Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

  2. Techniques for increasing output power from mode-locked semiconductor lasers

    SciTech Connect (OSTI)

    Mar, A.; Vawter, G.A.

    1996-02-01T23:59:59.000Z

    Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers have not yet approached the performance of such systems in terms of output power. Different techniques for overcoming the problem of low output power from mode-locked semiconductor lasers will be discussed. Flared and arrayed lasers have been used successfully to increase the pulse saturation energy limit by increasing the gain cross section. Further improvements have been achieved by use of the MOPA configuration, which utilizes a flared semiconductor amplifier s amplify pulses to energies of 120 pJ and peak powers of nearly 30W.

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

    DOE Patents [OSTI]

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

    2003-09-23T23:59:59.000Z

    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.

  4. Adaptive control of femtosecond pulse propagation in optical fibers

    SciTech Connect (OSTI)

    Omenetto, F. G. (Fiorenzo G.); Taylor, Antoinette J.,; Moores, M. D. (Mark D.); Reitze, David H.

    2001-01-01T23:59:59.000Z

    We present an adaptive control loop that synthesizes fs-pulses that are self-correcting for higher order nonlinear effects when launched in a conventional single-mode fiber, nearly preserving the initial (t{approx}200 fs) pulse duration.

  5. Long pulse production from short pulses

    DOE Patents [OSTI]

    Toeppen, John S. (Livermore, CA)

    1994-01-01T23:59:59.000Z

    A method of producing a long output pulse (SA) from a short pump pulse (P), using an elongated amplified fiber (11) having a doped core (12) 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 13. A seed beam (S) of the longer wavelength is injected into the core (12) at one end of the fiber (11) and a pump pulse (P) of the shorter wavelength is injected into the cladding (13) at the other end of the fiber (11). The counter-propagating seed beam (S) and pump pulse (P) will produce an amplified output pulse (SA) having a time duration equal to twice the transit time of the pump pulse (P) through the fiber (11) plus the length of the pump pulse (P).

  6. Long pulse production from short pulses

    DOE Patents [OSTI]

    Toeppen, J.S.

    1994-08-02T23:59:59.000Z

    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.

  7. Static magnetic and microwave properties of Li-ferrite films prepared by pulsed laser deposition

    E-Print Network [OSTI]

    Patton, Carl

    Static magnetic and microwave properties of Li-ferrite films prepared by pulsed laser deposition F University, Fort Collins, Colorado 80523 Highly textured Li-ferrite films have been synthesized by pulsed approaching 1000 °C the growth mode was predominantly 333 . A similar growth mode was recently reported for Ni-ferrite

  8. 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)

    2014-06-15T23:59:59.000Z

    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.

  9. 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)

    2014-09-28T23:59:59.000Z

    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{sub 2}O{sub 2}) 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{sub 2}O{sub 2} 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.

  10. Deep reflection-mode photoacoustic imaging of

    E-Print Network [OSTI]

    Wang, Lihong

    near-infrared laser pulses of 804-nm wavelength for PA excitation to achieve deep penetration-frequency PAM system. To achieve deep penetration of light, we chose the 804-nm near-infrared wavelengthDeep reflection-mode photoacoustic imaging of biological tissue Kwang Hyun Song and Lihong V. Wang

  11. Theoretical description of spontaneous pulse formation in a semiconductor microring laser

    SciTech Connect (OSTI)

    Gil, L.; Columbo, L. [Institut du Non Lineaire de Nice (Unite Mixte de Recherche-Centre National de la Recherche Scientifique 6618) Universite de Nice Sophia Antipolis, 1361 Route des Lucioles, F-06560 Valbonne (France); Consiglio Nazionale delle Ricerche-Istituto di Fotonica e Nanotecnologie, Dipartimento Interuniversitario di Fisica, via Amendola, 173, 70126 Bari (Italy)

    2011-01-15T23:59:59.000Z

    We theoretically describe the spontaneous formation of stable pulses in a GaAs bulk semiconductor microring laser. These pulses are obtained without active or passive mode locking. We show that the parameter regime associated with their existence is limited on one side by the phase instability of the continuous-wave solution, and on the other side by the failure of Lamb's mode-locking criterion. Bistability between the continuous-wave solution and the spontaneous pulses is observed.

  12. Optically pulsed electron accelerator

    DOE Patents [OSTI]

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

    1985-05-20T23:59:59.000Z

    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.

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

    DOE Patents [OSTI]

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

    1993-12-14T23:59:59.000Z

    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.

  14. High voltage pulse conditioning

    DOE Patents [OSTI]

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

    1990-01-01T23:59:59.000Z

    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. Critical pulse power components

    SciTech Connect (OSTI)

    Sarjeant, W.J.; Rohwein, G.J.

    1981-01-01T23:59:59.000Z

    Critical components for pulsed power conditioning systems will be reviewed. Particular emphasis will be placed on those components requiring significant development efforts. Capacitors, for example, are one of the weakest elements in high-power pulsed systems, especially when operation at high-repetition frequencies for extended periods of time are necessary. Switches are by far the weakest active components of pulse power systems. In particular, opening switches are essentially nonexistent for most applications. Insulaton in all systems and components requires development and improvement. Efforts under way in technology base development of pulse power components will be discussed.

  16. 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

  17. Pulse-mode temperature sensing with langasite SAW devices

    E-Print Network [OSTI]

    Greve, David.W.

    is increasingly important for many industrial processes, such as control of oxy-fuel combustion in several papers with wired gas and temperature sensing demonstrated up to 1000 ºC [7-11], and wireless

  18. Pulse pile-up effects

    SciTech Connect (OSTI)

    Tenney, F.H.

    1983-05-01T23:59:59.000Z

    The energy spectrum containing the effects of all orders of pulse pileup is predicted for an idealized x-ray pulse-height-analysis system measuring randomly occurring events. Two simplifying assumptions used are first a fixed pulse resolution time and second that the measured energy of piled-up pulses is the algebraic sum of the energy associated with each pulse.

  19. Invited Article: Coherent imaging using seeded free-electron laser pulses with variable polarization: First results and research opportunities

    SciTech Connect (OSTI)

    Capotondi, F.; Pedersoli, E.; Mahne, N.; Menk, R. H.; Passos, G.; Raimondi, L.; Svetina, C.; Sandrin, G.; Kiskinova, M. [FERMI, Elettra-Sincrotrone Trieste, SS 14 - km 163.5, 34149 Basovizza, Trieste (Italy); Zangrando, M. [FERMI, Elettra-Sincrotrone Trieste, SS 14 - km 163.5, 34149 Basovizza, Trieste (Italy); CNR, Istituto Officina dei Materiali - TASC, SS 14 - km 163.5, 34149 Basovizza, Trieste (Italy); Bajt, S.; Barthelmess, M.; Fleckenstein, H.; Chapman, H. N. [CFEL-DESY, Notkestrasse 85, 22607 Hamburg (Germany); Schulz, J. [European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Bach, J.; Froemter, R. [Universitaet Hamburg, Institut fuer Angewandte Physik, 20355 Hamburg (Germany); Schleitzer, S.; Mueller, L.; Gutt, C. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); and others

    2013-05-15T23:59:59.000Z

    FERMI-Elettra, the first vacuum ultraviolet and soft X-ray free-electron laser (FEL) using by default a 'seeded' scheme, became operational in 2011 and has been opened to users since December 2012. The parameters of the seeded FERMI FEL pulses and, in particular, the superior control of emitted radiation in terms of spectral purity and stability meet the stringent requirements for single-shot and resonant coherent diffraction imaging (CDI) experiments. The advantages of the intense seeded FERMI pulses with variable polarization have been demonstrated with the first experiments performed using the multipurpose experimental station operated at the diffraction and projection imaging (DiProI) beamline. The results reported here were obtained with fixed non-periodic targets during the commissioning period in 2012 using 20-32 nm wavelength range. They demonstrate that the performance of the FERMI FEL source and the experimental station meets the requirements of CDI, holography, and resonant magnetic scattering in both multi- and single-shot modes. Moreover, we present the first magnetic scattering experiments employing the fully circularly polarized FERMI pulses. The ongoing developments aim at pushing the lateral resolution by using shorter wavelengths provided by double-stage cascaded FERMI FEL-2 and probing ultrafast dynamic processes using different pump-probe schemes, including jitter-free seed laser pump or FEL-pump/FEL-probe with two color FEL pulses generated by the same electron bunch.

  20. Dynamic photorefractivity guided by single-pulse voltage

    SciTech Connect (OSTI)

    Agashkov, A. V., E-mail: agashkov@inel.bas.net.by; Kovalev, A. A. [National Academy of Sciences of Belarus, Institute of Electronics (Belarus); Parka, J. [Military University of Technology, Institute of Applied Physics (Poland)

    2008-03-15T23:59:59.000Z

    The dynamic photorefractivity in a cell with photoconducting orienting layers, filled with a nematic liquid crystal (LC) 6CHBT and a mixture of anthraquinone dyes AD1 and AD2, has been investigated. The single-pulse mode, in which the polarity and amplitude of a dc electric field applied to an LC cell are switched for a fixed time interval, has been used. The scheme of dynamic self-diffraction of low-power laser beams was used in the experiment. The dependences of the width and intensity of diffraction pulses on the bias and switching voltages have been investigated. It is established that the width and intensity of the diffraction pulse arising after initial voltage recovery depends also on the switching pulse width. At the optimal width of the control pulse, the diffraction efficiency increases by two orders of magnitude.

  1. Pulsed electrodeposition. Final report

    SciTech Connect (OSTI)

    Stimetz, C.J.

    1985-02-01T23:59:59.000Z

    Pulse plating of cobalt-hardened gold alloys increases the cobalt content in the alloy. At lower duty cycles, the electrodeposits become dull. Little change in the microhardness was observed between pulsed and direct current electrodeposits. The TEM and electron diffraction analyses indicated no significant difference in microstructure between pulsed and conventional gold alloy electrodeposits. Pulse plated and conventional nickel deposits have been compared for differences in morphology, mechanical properties, and microstructure. The deposits were obtained from nickel sulfamate, nickel chloride, and Watts nickel plating solutions. No significant differences were found in the direct and pulse current deposits from the sulfamate and chloride solutions; however, significant differences in microstructure, yield strength, and microhardness were observed in deposits from the Watts nickel solution.

  2. Chaotic Pulse Trains

    E-Print Network [OSTI]

    N. J. Balmforth; G. R. Ierley; E. A. Spiegel

    1993-09-08T23:59:59.000Z

    We study a third-order nonlinear ordinary differential equation whose solutions, under certain specific conditions, are individual pulses. These correspond to homoclinic orbits in the phase space of the equation and we study the possible pulse types in some detail. Sufficiently close to the conditions under which a homoclinic orbit exists, the solutions take the form of trains of well-separated pulses. A measure of closeness to homoclinic conditions provides a small parameter for the development of an asymptotic solution consisting of superposed, isolated pulses. The solvability condition in the resulting singular perturbation theory is a {\\its timing map} relating successive pulse spacings. This map of the real line onto itself, together with the known form of the homoclinic orbit, provides a concise and accurate solution of the equation.

  3. List mode multichannel analyzer

    DOE Patents [OSTI]

    Archer, Daniel E. (Livermore, CA); Luke, S. John (Pleasanton, CA); Mauger, G. Joseph (Livermore, CA); Riot, Vincent J. (Berkeley, CA); Knapp, David A. (Livermore, CA)

    2007-08-07T23:59:59.000Z

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  4. Kink modes in pedestal

    SciTech Connect (OSTI)

    Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China) [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Dong, J. Q.; Wang, Z. H.; Xu, M. [Southwestern Institute of Physics, Chengdu 610041 (China)] [Southwestern Institute of Physics, Chengdu 610041 (China); Xu, X. L.; Mou, M. L.; Sun, T. T.; Huang, J.; Chen, S. Y.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)] [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

    2014-03-15T23:59:59.000Z

    Kink modes are investigated in pedestal for shaped tokamaks. An analytic combining criterion is presented. It lies on the middle of the sufficient criterion of Lortz and necessary criterion of Mercier giving a more restricted necessary criterion. Growth rates and mode structure are calculated. For large poloidal mode number, the modes are highly localized in both poloidal and radial directions. The modes increase rapidly when they approach to the resonant surface. They are typical of edge localized modes (ELMs). It is assumed that the modes vanish inside the next resonant surface, then, there seems to be a second stable region. Several mitigation methods for controlling ELMs are proposed.

  5. Are "EIT Waves" Fast-Mode MHD Waves?

    E-Print Network [OSTI]

    M. J. Wills-Davey; C. E. DeForest; J. O. Stenflo

    2007-04-23T23:59:59.000Z

    We examine the nature of large-scale, coronal, propagating wave fronts (``EIT waves'') and find they are incongruous with solutions using fast-mode MHD plane-wave theory. Specifically, we consider the following properties: non-dispersive single pulse manifestions, observed velocities below the local Alfven speed, and different pulses which travel at any number of constant velocities, rather than at the ``predicted'' fast-mode speed. We discuss the possibility of a soliton-like explanation for these phenomena, and show how it is consistent with the above-mentioned aspects.

  6. Pulse measurement apparatus and method

    DOE Patents [OSTI]

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

    2011-10-25T23:59:59.000Z

    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.

  7. Pulse magnetic welder

    DOE Patents [OSTI]

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

    1984-01-01T23:59:59.000Z

    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.

  8. Schwinger Pair Production in Pulsed Electric Fields

    E-Print Network [OSTI]

    Sang Pyo Kim; Hyung Won Lee; Remo Ruffini

    2012-07-22T23:59:59.000Z

    We numerically investigate the temporal behavior and the structure of longitudinal momentum spectrum and the field polarity effect on pair production in pulsed electric fields in scalar quantum electrodynamics (QED). Using the evolution operator expressed in terms of the particle and antiparticle operators, we find the exact quantum states under the influence of electric pulses and measure the number of pairs of the Minkowski particle and antiparticle. The number of pairs, depending on the configuration of electric pulses, exhibits rich structures in the longitudinal momentum spectrum and undergoes diverse dynamical behaviors at the onset of the interaction but always either converges to a momentum-dependent constant or oscillates around a momentum-dependent time average after the completion of fields.

  9. Drop shaping by laser-pulse impact

    E-Print Network [OSTI]

    Klein, Alexander L; Visser, Claas Willem; Lhuissier, Henri; Sun, Chao; Snoeijer, Jacco H; Villermaux, Emmanuel; Lohse, Detlef; Gelderblom, Hanneke

    2015-01-01T23:59:59.000Z

    We study the hydrodynamic response of a falling drop hit by a laser pulse. Combining high-speed with stroboscopic imaging we report that a millimeter-sized dyed water drop hit by a milli-Joule nanosecond laser-pulse deforms and propels forward at several meters per second, until it eventually fragments. We show that the drop motion results from the recoil momentum imparted at the drop surface by water vaporization. We measure the propulsion speed and the time-deformation law of the drop, complemented by boundary integral simulations. We explain the drop propulsion and shaping in terms of the laser pulse energy and drop surface tension. These findings are crucial for the generation of extreme ultraviolet (EUV) light in lithography machines.

  10. Pulse shaping with transmission lines

    DOE Patents [OSTI]

    Wilcox, Russell B. (Oakland, CA)

    1987-01-01T23:59:59.000Z

    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.

  11. Pulse shaping with transmission lines

    DOE Patents [OSTI]

    Wilcox, R.B.

    1985-08-15T23:59:59.000Z

    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.

  12. Singular Modes of the Electromagnetic Field

    E-Print Network [OSTI]

    Neil V. Budko; Alexander B. Samokhin

    2006-06-15T23:59:59.000Z

    We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.

  13. Singular Modes of the Electromagnetic Field

    E-Print Network [OSTI]

    Budko, N V; Budko, Neil V.; Samokhin, Alexander B.

    2006-01-01T23:59:59.000Z

    We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.

  14. Photoconductive circuit element pulse generator

    DOE Patents [OSTI]

    Rauscher, Christen (Alexandria, VA)

    1989-01-01T23:59:59.000Z

    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.

  15. Modes of log gravity

    SciTech Connect (OSTI)

    Bergshoeff, Eric A.; Rosseel, Jan [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Hohm, Olaf [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Townsend, Paul K. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2011-05-15T23:59:59.000Z

    The physical modes of a recently proposed D-dimensional 'critical gravity', linearized about its anti-de Sitter vacuum, are investigated. All 'log mode' solutions, which we categorize as 'spin-2' or 'Proca', arise as limits of the massive spin-2 modes of the noncritical theory. The linearized Einstein tensor of a spin-2 log mode is itself a 'nongauge' solution of the linearized Einstein equations whereas the linearized Einstein tensor of a Proca mode takes the form of a linearized general coordinate transformation. Our results suggest the existence of a holographically dual logarithmic conformal field theory.

  16. Effect of high-voltage nanosecond pulses on complex plasmas

    SciTech Connect (OSTI)

    Pustylnik, M. Y.; Ivlev, A. V.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, 85741 Garching (Germany); Vasilyak, L. M.; Vetchinin, S. P.; Polyakov, D. N.; Fortov, V. E. [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13/19, 125412 Moscow (Russian Federation)

    2009-11-15T23:59:59.000Z

    Influence of high-voltage (1-11 kV) pulses of nanosecond (20 ns) duration on microparticles levitating in a rf plasma is studied. It is shown that the pulses produce significant influence on the plasma, causing perturbations with the relaxation time of the order of 10{sup -4} s. This time is sufficient for the microparticle to acquire significant kinetic energy. Application of repetitive pulses leads to the vertical oscillations of the microparticles. Clusters, consisting of small number of microparticles, exhibit parametric instabilities of horizontal modes under the effect of repetitive pulses. It was shown that the parametric instability is caused by the vertical oscillations of the microparticles in the nonuniform environment of the sheath.

  17. HydroPulse Drilling

    SciTech Connect (OSTI)

    J.J. Kolle

    2004-04-01T23:59:59.000Z

    Tempress HydroPulse{trademark} tool increases overbalanced drilling rates by generating intense suction pulses at the drill bit. This report describes the operation of the tool; results of pressure drilling tests, wear tests and downhole drilling tests; and the business case for field applications. The HydroPulse{trademark} tool is designed to operate on weighted drilling mud at conventional flow rates and pressures. Pressure drilling tests confirm that the HydroPulse{trademark} tool provides 33% to 200% increased rate of penetration. Field tests demonstrated conventional rotary and mud motor drilling operations. The tool has been operated continuous for 50 hours on weighted mud in a wear test stand. This level of reliability is the threshold for commercial application. A seismic-while-drilling version of the tool was also developed and tested. This tool was used to demonstrate reverse vertical seismic profiling while drilling an inclined test well with a PDC bit. The primary applications for the HydroPulse{trademark} tool are deep onshore and offshore drilling where rate of penetration drives costs. The application of the seismic tool is vertical seismic profiling-while-drilling and look-ahead seismic imaging while drilling.

  18. Radiation Related Terms Basic Terms

    E-Print Network [OSTI]

    Vallino, Joseph J.

    Radiation Related Terms Basic Terms Radiation Radiation is energy in transit in the form of high not carry enough energy to separate molecules or remove electrons from atoms. Ionizing radiation Ionizing radiation is radiation with enough energy so that during an interaction with an atom, it can remove tightly

  19. To Expected Charge Fluctuations Data from the long pulse run 17-Feb-2002

    E-Print Network [OSTI]

    Te if possible - button BPMs equipped with electronics from the undulator - additional stripline BPM BIS long pulse operation mode in analysis mode reentrant BPM Protvino BPM dogleg +vertical steerers stripline BPM button BPMs button BPM beamdump 25 MeV beam, 8mA@10 Hz #12;Resolution of the Injector

  20. Pulse shaping system

    DOE Patents [OSTI]

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

    1999-03-23T23:59:59.000Z

    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.

  1. Pulse shaping system

    DOE Patents [OSTI]

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

    1999-03-23T23:59:59.000Z

    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.

  2. Pulsed neutron detector

    DOE Patents [OSTI]

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

    1989-03-21T23:59:59.000Z

    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.

  3. 208 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, VOL. 11, NO. 5, MAY 2001 Novel Low-Cost Ultra-Wideband, Ultra-Short-Pulse

    E-Print Network [OSTI]

    Arslan, Hüseyin

    -to-peak and a pulse repetition rate of 10 MHz. The measured pulses have good symmetry and low ringing level. Index Terms--Ground penetrating radar, MIC, pulse generator, transmitter, ultra-wideband radar. I. INTRODUCTION ULTRA-wideband (UWB), ultra-short pulses are very at- tractive for radar and wireless

  4. Self-pulsing of hollow cathode discharge in various gases

    SciTech Connect (OSTI)

    Qin, Y.; He, F., E-mail: hefeng@bit.edu.cn; Jiang, X. X.; Ouyang, J. T., E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Xie, K. [School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China)

    2014-07-15T23:59:59.000Z

    In this paper, we investigate the self-pulsing phenomenon of cavity discharge in a cylindrical hollow cathode in various gases including argon, helium, nitrogen, oxygen, and air. The current-voltage characteristics of the cavity discharge, the waveforms of the self-pulsing current and voltage as well as the repetition frequency were measured. The results show that the pulsing frequency ranges from a few to tens kilohertz and depends on the averaged current and the pressure in all gases. The pulsing frequency will increase with the averaged current and decrease with the pressure. The rising time of the current pulse is nearly constant in a given gas or mixture. The self-pulsing does not depend on the external ballast but is affected significantly by the external capacitor in parallel with the discharge cell. The low-current self-pulsing in hollow cathode discharge is the mode transition between Townsend and glow discharges. It can be described by the charging-discharging process of an equivalent circuit consisting of capacitors and resistors.

  5. Slow-light propagation using mode locking of spin precession in quantum dots

    SciTech Connect (OSTI)

    Shabaev, A. [George Mason University, Fairfax Virginia 22030 (United States); Dutton, Z. [Raytheon BBN Technologies, 10 Moulton Street, Cambridge, Massachusetts 02138 (United States); Naval Research Laboratory, Washington, D.C. 20375 (United States); Kennedy, T. A.; Efros, Al. L. [Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2010-11-15T23:59:59.000Z

    We propose using mode locking to enable coherent nonlinear optical effects in inhomogenously broadened spin ensembles. We carry out detailed calculations for quantum dot systems in which increased spin coherence via mode locking has been recently observed [A. Greilich et al., Science 313, 341 (2006); 317, 1896 (2007)]. We show how, in the presence of spin locking, a strong pulse-matching effect occurs, providing a powerful tool for high-bandwidth linear optical processing. We then go on to study 'slow light' in this system and show that high-bandwidth pulses can be controllably delayed by a time comparable to the pulse width.

  6. Downhole pulse tube refrigerators

    SciTech Connect (OSTI)

    Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

    1997-12-01T23:59:59.000Z

    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.

  7. Passively harmonic mode locked erbium doped fiber soliton laser with carbon nanotubes based

    E-Print Network [OSTI]

    Turitsyn, Sergei K.

    Passively harmonic mode locked erbium doped fiber soliton laser with carbon nanotubes based. Tokumoto, H. Kataura, and Y. Achiba, "Sub-200-fs pulsed erbium- doped fiber laser using a carbon nanotube fs erbium-doped fiber laser mode locked with a cellulose polymer film containing single-wall carbon

  8. Sequentially pulsed traveling wave accelerator

    DOE Patents [OSTI]

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

    2009-08-18T23:59:59.000Z

    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.

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

    SciTech Connect (OSTI)

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

    2009-03-18T23:59:59.000Z

    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.

  10. Architecture AddressingModes

    E-Print Network [OSTI]

    Nguyen, Dat H.

    MIPS R2000 Architecture and Assembly (Part 1) 1. CPU Registers 2. Byte Order 3. AddressingModes 4­endian byte order 3 2 1 0 0 1 2 3 Or Byte number #12; AddressingModes . MIPS is a load/store architecture . RICS -- Load/Store architecture -- All instructions have equal length of 4 bytes -- Every register can

  11. 190-fs passively mode-locked thulium fiber laser with a low threshold

    SciTech Connect (OSTI)

    Sharp, R.C.; Spock, D.E.; Pan, N.; Elliot, J. [Raytheon Company, Electronic Systems, 131 Spring Street, Lexington, Massachusetts 02173 (United States)

    1996-06-01T23:59:59.000Z

    We report a self-starting passively mode-locked thulium-doped silica fiber laser capable of 190-fs pulses. This practical, compact package is driven by a single 50-mW passively cooled diode laser, has a launched pump-power threshold of 18 mW for mode locking, and produces a 50-MHz train of mode-locked 20-pJ pulses at a wavelength near 1.9 {mu}m. {copyright} {ital 1996 Optical Society of America.}

  12. Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker

    E-Print Network [OSTI]

    Han Zhang; Qiaoliang Bao; Dingyuan Tang; Luming Zhao; Kianping Loh

    2009-09-30T23:59:59.000Z

    Due to its unique electronic property and the Pauli Blocking Principle, atomic layer graphene possesses wavelength-independent ultrafast saturable absorption, which can be exploited for the ultrafast photonics application. Through chemical functionalization, a graphene-polymer nanocomposite membrane was fabricated and firstly used to mode lock a fiber laser. Stable mode locked solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength have been directly generated from the laser. We show that graphene-polymer nanocomposites could be an attractive saturable absorber for high power fiber laser mode locking.

  13. Zero-mode waveguides

    DOE Patents [OSTI]

    Levene, Michael J.; Korlach, Jonas; Turner, Stephen W.; Craighead, Harold G.; Webb, Watt W.

    2007-02-20T23:59:59.000Z

    The present invention is directed to a method and an apparatus for analysis of an analyte. The method involves providing a zero-mode waveguide which includes a cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide. The analyte is positioned in the core of the zero-mode waveguide and is then subjected, in the core of the zero-mode waveguide, to activating electromagnetic radiation of a frequency less than the cut-off frequency under conditions effective to permit analysis of the analyte in an effective observation volume which is more compact than if the analysis were carried out in the absence of the zero-mode waveguide.

  14. Downhole pulse radar

    DOE Patents [OSTI]

    Chang, Hsi-Tien

    1987-09-28T23:59:59.000Z

    A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole. 7 figs.

  15. Ptychographic ultrafast pulse reconstruction

    E-Print Network [OSTI]

    Spangenberg, D; Brügmann, M H; Feurer, T

    2014-01-01T23:59:59.000Z

    We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

  16. 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. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2013-10-15T23:59:59.000Z

    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.

  17. International magnetic pulse compression workshop: (Proceedings)

    SciTech Connect (OSTI)

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

    1991-04-01T23:59:59.000Z

    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.

  18. 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)

    2010-03-16T23:59:59.000Z

    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.

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

    DOE Patents [OSTI]

    Burkhart, Scott C. (Livermore, CA)

    2002-01-01T23:59:59.000Z

    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.

  20. 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)

    2014-03-07T23:59:59.000Z

    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.

  1. Mixed-mode oscillations in chemical systems Valery Petrov

    E-Print Network [OSTI]

    Showalter, Kenneth

    , leading to correspondingly more complete Devil's staircases. An ex- actly comparable scenario is shown. The relative extents of the mixed-mode and nonmixed- mode forms are summarized in terms of a Devil's staircase. The completeness of the staircase as a second parameter is varied is discussed. The mechanisms by which the system

  2. 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)

    2012-09-15T23:59:59.000Z

    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.

  3. Coiled transmission line pulse generators

    DOE Patents [OSTI]

    McDonald, Kenneth Fox (Columbia, MO)

    2010-11-09T23:59:59.000Z

    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.

  4. Green Light Pulse Oximeter

    DOE Patents [OSTI]

    Scharf, John Edward (Oldsmar, FL)

    1998-11-03T23:59:59.000Z

    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.

  5. Pulsed Zeeman spectroscopy

    E-Print Network [OSTI]

    Cullen, Raymond Paul

    2012-06-07T23:59:59.000Z

    wheel was attached to the wavei( ngth indicator and was used to interrupt the light striking a small photodiode. The output voltage from the photodiode was used to provide calibration points on the recorder. Photomultiplier An Amperex 56UVP... Vertical: 2 mv/cm Horizontal: 5 microseconds/cm 23 Phc tographic Measurements ~A. Ald t p t 1 pbd. db spectra of ruby as in Fig. l. A photodiode with a risetime of four nanoseconds was used to position the magneti. c field pulse in order...

  6. 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

    2015-01-01T23:59:59.000Z

    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 ...

  7. Spectrally tailored supercontinuum generation from single-mode-fiber amplifiers

    SciTech Connect (OSTI)

    Hao, Qiang; Guo, Zhengru; Zhang, Qingshan [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); Liu, Yang; Li, Wenxue [State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China)

    2014-05-19T23:59:59.000Z

    Spectral filtering of an all-normal-dispersion Yb-doped fiber laser was demonstrated effective for broadband supercontinuum generation in the picosecond time region. The picosecond pump pulses were tailored in spectrum with 1 nm band-pass filter installed between two single-mode fiber amplifiers. By tuning the spectral filter around 1028?nm, four-wave mixing was initiated in a photonic crystal fiber spliced with single-mode fiber, as manifested by the simultaneous generation of Stokes wave at 1076?nm and anti-Stokes wave at 984?nm. Four-wave mixing took place in cascade with the influence of stimulated Raman scattering and eventually extended the output spectrum more than 900?nm of 10?dB bandwidth. This technique allows smooth octave supercontinuum generation by using simple single-mode fiber amplifiers rather than complicated multistage large-mode-area fiber amplifiers.

  8. Classical and Quantum Dynamics of Free Electromagnetic Laser Pulses

    E-Print Network [OSTI]

    Goto, S; Walton, T J

    2015-01-01T23:59:59.000Z

    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. Bipolar pulse forming line

    DOE Patents [OSTI]

    Rhodes, Mark A. (Pleasanton, CA)

    2008-10-21T23:59:59.000Z

    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.

  10. Switching power pulse system

    DOE Patents [OSTI]

    Aaland, K.

    1983-08-09T23:59:59.000Z

    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.

  11. Ultra-short pulse generator

    DOE Patents [OSTI]

    McEwan, T.E.

    1993-12-28T23:59:59.000Z

    An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shock wave diode, which increases and sharpens the pulse even more. 5 figures.

  12. Precision lifetime measurements of a single trapped ion with ultrafast laser pulses D. L. Moehring,* B. B. Blinov, D. W. Gidley, R. N. Kohn, Jr., M. J. Madsen, T. D. Sanderson, R. S. Vallery, and C. Monroe

    E-Print Network [OSTI]

    Blinov, Boris

    Precision lifetime measurements of a single trapped ion with ultrafast laser pulses D. L. Moehring and ultrafast laser technologies, the ion is excited with picosecond laser pulses from a mode-locked laser excited state lifetime of order nanoseconds by an ultrafast laser pulse duration of order picoseconds

  13. Influence of frequency scanning on the operation of pulsed lasers with external signal injection

    SciTech Connect (OSTI)

    Gapotchenko, N.I.; Likhanskii, V.V.; Napartovich, A.P.

    1985-10-01T23:59:59.000Z

    An analysis is made of the influence of variation of the detuning of the frequency of a resonator mode from that of an external injected signal on the operation of pulsed gas lasers. It is found when the detuning is varied with time there is an increase in the width of the locking region of a resonator mode in pulsed lasers. The results are given of numerical calculations of the dependences of the locking efficiency on the parameters on the injected signal and of the laser active medium.

  14. Deterministic passive mode locking of solid-state lasers

    SciTech Connect (OSTI)

    Martinez, O.E.; Spinelli, L.A.

    1981-12-01T23:59:59.000Z

    An additional passive modulation is inserted in the cavity of a passive mode-locked Nd:glass laser in order to provide the conditions for a complete selectivity of the system. A rate equation approach shows that a stationary condition is reached in which only one pulse of the original fluctuation pattern is left. Computed simulations and experimental results are also shown confirming the theoretical predictions.

  15. Photon detection efficiency of Geiger-mode avalanche photodiodes

    E-Print Network [OSTI]

    Simonetta Gentile; Ekaterina Kuznetsova; Franco Meddi

    2010-06-16T23:59:59.000Z

    The photon detection efficiencies of multi-pixel Geiger-mode avalanche photodiodes manufactured by different produ cers are estimated. A new fit method of the response spectra to low-intensity light, taking into ac count after-pulse and cross-talk effects is proposed to yield the initial number of photons. The value of photon detection efficiency is calculated using a calibrated photodetector as a reference.

  16. Capacitor discharge pulse analysis.

    SciTech Connect (OSTI)

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01T23:59:59.000Z

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  17. Pulsed ion beam source

    DOE Patents [OSTI]

    Greenly, John B. (Lansing, NY)

    1997-01-01T23:59:59.000Z

    An improved pulsed ion beam source 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.

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

    DOE Patents [OSTI]

    Clarke, John M. (Chillicothe, IL)

    2003-08-05T23:59:59.000Z

    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.

  19. Switching power pulse system

    DOE Patents [OSTI]

    Aaland, Kristian (Livermore, CA)

    1983-01-01T23:59:59.000Z

    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.

  20. A current driven electromagnetic mode in sheared and toroidal configurations

    E-Print Network [OSTI]

    Pusztai, István; Parra, Felix I; Barnes, Michael

    2013-01-01T23:59:59.000Z

    The induced electric field in a tokamak drives a parallel electron current flow. In an inhomogeneous, finite beta plasma, when this electron flow is comparable to the ion thermal speed, the Alfven mode wave solutions of the electromagnetic gyrokinetic equation can become nearly purely growing kink modes. Using the new "low-flow" version of the gyrokinetic code GS2 developed for momentum transport studies [Barnes et al 2013 Phys. Rev. Lett. 111, 055005], we are able to model the effect of the induced parallel electric field on the electron distribution to study the destabilizing influence of current on stability. We identify high mode number kink modes in GS2 simulations and make comparisons to analytical theory in sheared magnetic geometry. We demonstrate reassuring agreement with analytical results both in terms of parametric dependences of mode frequencies and growth rates, and regarding the radial mode structure.

  1. Precision digital pulse phase generator

    DOE Patents [OSTI]

    McEwan, T.E.

    1996-10-08T23:59:59.000Z

    A timing generator comprises a crystal oscillator connected to provide an output reference pulse. A resistor-capacitor combination is connected to provide a variable-delay output pulse from an input connected to the crystal oscillator. A phase monitor is connected to provide duty-cycle representations of the reference and variable-delay output pulse phase. An operational amplifier drives a control voltage to the resistor-capacitor combination according to currents integrated from the phase monitor and injected into summing junctions. A digital-to-analog converter injects a control current into the summing junctions according to an input digital control code. A servo equilibrium results that provides a phase delay of the variable-delay output pulse to the output reference pulse that linearly depends on the input digital control code. 2 figs.

  2. Precision digital pulse phase generator

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1996-01-01T23:59:59.000Z

    A timing generator comprises a crystal oscillator connected to provide an output reference pulse. A resistor-capacitor combination is connected to provide a variable-delay output pulse from an input connected to the crystal oscillator. A phase monitor is connected to provide duty-cycle representations of the reference and variable-delay output pulse phase. An operational amplifier drives a control voltage to the resistor-capacitor combination according to currents integrated from the phase monitor and injected into summing junctions. A digital-to-analog converter injects a control current into the summing junctions according to an input digital control code. A servo equilibrium results that provides a phase delay of the variable-delay output pulse to the output reference pulse that linearly depends on the input digital control code.

  3. Electrodeless short pulse laser

    SciTech Connect (OSTI)

    Proud, J.M.; Baird, D.H.; Kramer, J.M.; Lester, J.E.

    1986-06-03T23:59:59.000Z

    A system is described for the generation of coherent beams of radiation, which consists of: a tube defining a resonant cavity containing a discharge plasma capable of producing coherent radiation, the tube having an elongated shape along an optical axis along the longitudinal axis of the tube, the tube having end portions and an elongated constricted portion connecting the end portions, and the tube having laser windows sealing the end portions to form a closed envelope containing the discharge plasma, a mirror on the optical axis near at least one end of the tube, first and second external electrode means on the outside surfaces of the tube adjacent the opposite ends of the tube, the external electrode means being capacitively coupled to the discharge plasma, and means for providing a source of short pulses electrically to the first external electrode means and means for coupling the second external electrode means to a point of reference potential, further characterized by first and second internal electrode means respectively adjacent the first and second external electrode means and capacitively coupled thereto, the tube having end portions sealed to form a closed envelope containing the discharge plasma and the internal electrode means.

  4. Pulsed ion beam source

    DOE Patents [OSTI]

    Greenly, J.B.

    1997-08-12T23:59:59.000Z

    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.

  5. Hyper dispersion pulse compressor for chirped pulse amplification systems

    DOE Patents [OSTI]

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

    2011-11-29T23:59:59.000Z

    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.

  6. Prefire identification for pulse power systems

    DOE Patents [OSTI]

    Longmire, Jerry L. (Los Alamos, NM); Thuot, Michael E. (Espanola, NM); Warren, David S. (Los Alamos, NM)

    1985-01-01T23:59:59.000Z

    Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

  7. Prefire identification for pulse-power systems

    DOE Patents [OSTI]

    Longmire, J.L.; Thuot, M.E.; Warren, D.S.

    1982-08-23T23:59:59.000Z

    Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

  8. Ultrasonic flowmetering with reflected pulses

    E-Print Network [OSTI]

    Hoyle, David C.

    1984-01-01T23:59:59.000Z

    A transit time type ultrasonic flowmeter was tested with two different reflected pulse trajectories in flowing air at ambient conditions against an orifice meter. The flowmeter was designed to be highly accurate, to require ...

  9. Design and testing of an internal mode converter for a 1.5 MW, 110 GHz gyrotron with a depressed collector

    E-Print Network [OSTI]

    Tax, David Samuel

    We report experimental results on a 1.5 MW, 110 GHz, 3 microsecond pulsed gyrotron with a single-stage depressed collector. A simplified mode converter with smooth mirror surfaces has been installed in the tube. The converter ...

  10. A mechanical mode-stirred reverberation chamber with chaotic geometry

    E-Print Network [OSTI]

    Gabriele Gradoni; Franco Moglie; Valter Mariani Primiani

    2014-07-06T23:59:59.000Z

    A previous research on multivariate approach to the calculation of reverberation chamber correlation matrices is used to calculate the number of independent positions in a mode-stirred reverberation chamber. Anomalies and counterintuitive behavior are observed in terms of number of correlated matrix elements with respect to increasing frequency. This is ascribed to the regular geometry forming the baseline cavity (screened room) of a reverberation chamber, responsible for localizing energy and preserving regular modes (bouncing ball modes). Smooth wall deformations are introduced in order to create underlying Lyapunov instability of rays and then destroy survived regular modes. Numerical full-wave simulations are performed for a reverberation chamber with corner hemispheres and (off-)center wall spherical caps. Field sampling is performed by moving a mechanical carousel stirrer. It is found that wave-chaos inspired baseline geometries improve chamber performances in terms of lowest usable frequencies and number of independent cavity realizations of mechanical stirrers.

  11. 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)

    1996-01-01T23:59:59.000Z

    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.

  12. 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)

    1994-01-01T23:59:59.000Z

    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.

  13. Femtosecond laser pulse generation with a fiber taper embedded in carbon

    E-Print Network [OSTI]

    Kieu, Khanh

    Femtosecond laser pulse generation with a fiber taper embedded in carbon nanotube/polymer composite and demonstrate a new saturable absorber based on a fiber taper embedded in a carbon nanotube/polymer composite absorber. Using an embedded fiber-taper saturable absorber, we built an all-fiber mode-locked ring laser

  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.

    1996-01-23T23:59:59.000Z

    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. A new procedure for static RAM evaluation under x-ray pulses

    SciTech Connect (OSTI)

    Marec, R.; Gaillard, R. (Nucletudes S.A., Les Ulis (France)); Mary, P.; Fairbank, X. (LRBA, Vernon (France)); Ferrant, R. (Thomson-CSF Semiconducteurs Specifiques, Saint Egreve (France)); Palau, J.M.; Gasiot, J. (Univ. Montpellier (France). Centre Electronique de Montpellier)

    1994-12-01T23:59:59.000Z

    An original method, to identify the initial patterns that are the most favorable to obtain upsets under X-ray pulses, has been developed on Static RAMs in the standby mode. The results obtained with these initial patterns are interesting in order to analyze the radiation induced failures.

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

    DOE Patents [OSTI]

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

    1994-02-15T23:59:59.000Z

    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.

  17. Vacuum electron acceleration by using two variable frequency laser pulses

    SciTech Connect (OSTI)

    Saberi, H.; Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

    2013-12-15T23:59:59.000Z

    A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

  18. Slow modes in Keplerian disks

    E-Print Network [OSTI]

    Scott Tremaine

    2000-11-30T23:59:59.000Z

    Low-mass disks orbiting a massive body can support "slow" normal modes, in which the eigenfrequency is much less than the orbital frequency. Slow modes are lopsided, i.e., the azimuthal wavenumber m=1. We investigate the properties of slow modes, using softened self-gravity as a simple model for collective effects in the disk. We employ both the WKB approximation and numerical solutions of the linear eigenvalue equation. We find that all slow modes are stable. Discrete slow modes can be divided into two types, which we label g-modes and p-modes. The g-modes involve long leading and long trailing waves, have properties determined by the self-gravity of the disk, and are only present in narrow rings or in disks where the precession rate is dominated by an external potential. In contrast, the properties of p-modes are determined by the interplay of self-gravity and other collective effects. P-modes involve both long and short waves, and in the WKB approximation appear in degenerate leading/trailing pairs. Disks support a finite number---sometimes zero---of discrete slow modes, and a continuum of singular modes.

  19. Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage

    SciTech Connect (OSTI)

    Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2011-01-01T23:59:59.000Z

    Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpine was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.

  20. Fluid modes of a spherically confined Yukawa plasma

    SciTech Connect (OSTI)

    Kaehlert, H.; Bonitz, M. [Institut fuer Theoretische Physik und Astrophysik, Christian-Albrechts Universitaet zu Kiel, 24098 Kiel (Germany)

    2010-09-15T23:59:59.000Z

    The normal modes of a three-dimensional Yukawa plasma in an isotropic harmonic confinement are investigated by solving the linearized cold fluid equations. The eigenmodes are found analytically and expressed in terms of hypergeometric functions. It is found that the mode frequencies solely depend on the dimensionless plasma parameter {xi}={kappa}R, where R is the plasma radius and {kappa} is the inverse screening length. The eigenfrequencies increase monotonically with {xi} and saturate in the limit {xi}{yields}{infinity}. Compared with the results in the Coulomb limit [D. H. E. Dubin, Phys. Rev. Lett. 66, 2076 (1991)], we find an additional class of modes characterized by the number n which determines the number of radial nodes in the perturbed potential. These modes originate from the degenerate bulk modes of the Coulomb system. Analytical formulas for the eigenfrequencies are derived for limiting cases.

  1. Sandia National Laboratories: 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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -theErik Spoerke SSLS ExhibitIowaLos Alamos NationalMHK FloatingMLPE SandiaMODE

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

    SciTech Connect (OSTI)

    Stercil, F. [University of Pennsylvania; Egami, T. [University of Pennsylvania; Mook Jr, Herbert A [ORNL; Yethiraj, Mohana [ORNL; Chung, J.-H. [National Institute of Standards and Technology (NIST); Arai, M. [Institute of Materials Structure Science, Japan; Frost, C. [ISIS Facility, Rutherford Appleton Laboratory; Dogan, F. [University of Washington, Seattle

    2008-01-01T23:59:59.000Z

    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.

  3. Impossibility of faithfully storing single photons with the three-pulse photon echo

    SciTech Connect (OSTI)

    Sangouard, Nicolas; Minar, Jiri; Afzelius, Mikael; Gisin, Nicolas; Riedmatten, Hugues de [Group of Applied Physics, University of Geneva, Geneva (Switzerland); Simon, Christoph; Tittel, Wolfgang [Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Chaneliere, Thierry; Le Goueet, Jean-Louis [Laboratoire Aime Cotton, CNRS-UPR 3321, Universite Paris-Sud, F-91405 Orsay cedex (France)

    2010-06-15T23:59:59.000Z

    The three-pulse photon echo is a well-known technique to store intense light pulses in an inhomogeneously broadened atomic ensemble. This protocol is attractive because it is relatively simple and it is well suited for the storage of multiple temporal modes. Furthermore, it offers very long storage times, greater than the phase relaxation time. Here, we consider the three-pulse photon echo in both two- and three-level systems as a potential technique for the storage of light at the single-photon level. By explicit calculations, we show that the ratio between the echo signal corresponding to a single-photon input and the noise is smaller than one. This severely limits the achievable fidelity of the quantum state storage, making the three-pulse photon echo unsuitable for single-photon quantum memory.

  4. Ionization by few-cycle pulses: Tracing the electron orbits

    SciTech Connect (OSTI)

    Milosevic, D.B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Paulus, G.G. [Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

    2005-06-15T23:59:59.000Z

    High-order above-threshold ionization by few-cycle laser pulses is analyzed in terms of quantum orbits. For a given carrier-envelope phase, the number of contributing orbits and their ionization and rescattering times determine the shape of the angle-resolved spectrum in all detail. Conversely, analysis of a given spectrum reveals the carrier-envelope phase and the various interfering pathways from which the electron could choose.

  5. Radial flow pulse jet mixer

    DOE Patents [OSTI]

    VanOsdol, John G.

    2013-06-25T23:59:59.000Z

    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.

  6. Pulse combustor with controllable oscillations

    DOE Patents [OSTI]

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

    1992-01-01T23:59:59.000Z

    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.

  7. Mach 5 bow shock control by a nanosecond pulse surface dielectric barrier discharge

    SciTech Connect (OSTI)

    Nishihara, M.; Takashima, K.; Rich, J. W.; Adamovich, I. V. [Michael A. Chaszeyka Nonequilibrium Thermodynamics Laboratories, Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

    2011-06-15T23:59:59.000Z

    Bow shock perturbations in a Mach 5 air flow, produced by low-temperature, nanosecond pulse, and surface dielectric barrier discharge (DBD), are detected by phase-locked schlieren imaging. A diffuse nanosecond pulse discharge is generated in a DBD plasma actuator on a surface of a cylinder model placed in air flow in a small scale blow-down supersonic wind tunnel. Discharge energy coupled to the actuator is 7.3-7.8 mJ/pulse. Plasma temperature inferred from nitrogen emission spectra is a few tens of degrees higher than flow stagnation temperature, T = 340 {+-} 30 K. Phase-locked Schlieren images are used to detect compression waves generated by individual nanosecond discharge pulses near the actuator surface. The compression wave propagates upstream toward the baseline bow shock standing in front of the cylinder model. Interaction of the compression wave and the bow shock causes its displacement in the upstream direction, increasing shock stand-off distance by up to 25%. The compression wave speed behind the bow shock and the perturbed bow shock velocity are inferred from the Schlieren images. The effect of compression waves generated by nanosecond discharge pulses on shock stand-off distance is demonstrated in a single-pulse regime (at pulse repetition rates of a few hundred Hz) and in a quasi-continuous mode (using a two-pulse sequence at a pulse repetition rate of 100 kHz). The results demonstrate feasibility of hypersonic flow control by low-temperature, repetitive nanosecond pulse discharges.

  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)

    2012-08-15T23:59:59.000Z

    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. Accuracy of Analog Fiber-Optic Links in Pulsed Radiation Environments

    SciTech Connect (OSTI)

    E. K. Miller, G. S. Macrum, I. J. McKenna, et al.

    2007-12-01T23:59:59.000Z

    Interferometric fiber-optic links used in pulsed-power experiments are evaluated for accuracy in the presence of radiation fields which alter fiber transmission. Amplitude-modulated format (e.g., Mach-Zehnder) and phase-modulated formats are compared. Historically, studies of radiation effects on optical fibers have focused on degradation and recovery of the fibers transmission properties; such work is either in the context of survivability of fibers in catastrophic conditions or suitability of fibers installed for command and control systems within an experimental facility [1], [2]. In this work, we consider links used to transmit realtime diagnostic data, and we analyze the error introduced by radiation effects during the drive pulse. The result is increased uncertainties in key parameters required to unfold the sinusoidal transfer function. Two types of modulation are considered: amplitude modulation typical of a Mach-Zehnder (M-Z) modulator [3], and phase modulation, which offers more flexible demodulation options but relies on the spatiotemporal coherence of the light in the fiber. The M-Z link is shown schematically in Fig. 1, and the phase-modulated link is shown in Fig. 2. We present data from two experimental environments: one with intense, controlled radiation fields to simulate conditions expected at the next generation of pulsed-power facilities, and the second with radiation effects below the noise level of the recording system. In the first case, we intentionally expose three types of single-mode fiber (SMF) to ionizing radiation and study the response by simultaneously monitoring phase and amplitude of the transmitted light. The phase and amplitude effects are evidently dominated by different physical phenomena, as their recovery dynamics are markedly different; both effects, though, show similar short-term behavior during exposure, integrating the dose at the dose levels studied, from 1 to 300 kRad, over the exposure times of 50 ps and 30 ns. In the second case, we present data using a state-of-the-art fiber-optic link for single-shot transmission and recording, fielded at the OMEGA laser facility on high-yield fusion experiments. Gamma reaction history data are measured with a gas Cherenkov detector (GCD) [4], [5] and transmitted by M-Z link to a 12 GHz digitizer. Since radiation effects on the fibers are not above the noise floor, the error analysis for the unfolded data is dominated by the performance of the fast digitizer, the photoreceiver, and the laser.

  10. Radio frequency-power and the ring-mode to red-mode transition in an inductively coupled plasma

    SciTech Connect (OSTI)

    Coffer, J. G.; Camparo, J. C. [Physical Sciences Laboratories, The Aerospace Corporation, P.O. Box 92957, Los Angeles, California 90009 (United States)

    2012-04-15T23:59:59.000Z

    The optical output of an alkali-metal inductively coupled plasma (alkali-ICP) plays an important role in both atomic magnetometers and atomic clocks, producing these devices' atomic signals through optical pumping. Unfortunately, though the alkali-ICP's optical pumping efficiency grows exponentially with temperature, at relatively high temperatures ({approx}140 deg. C) the discharge transitions from ''ring mode'' to ''red mode'', which is a spectral change in the plasma's output that corresponds broadly to a transition from ''good emission'' for optical pumping to ''poor emission.'' Recently, evidence has accumulated pointing to radiation trapping as the mechanism driving the ring-mode to red-mode transition, suggesting that the phenomenon is primarily linked to the alkali vapor's temperature. However, observations of the transition made in the 1960 s, demonstrating that the ICP temperature associated with the transition depended on rf-power, would appear to cast doubt on this mechanism. Here, we carefully investigate the influence of rf-power on the ring-mode to red-mode transition, finding that rf-power only affects the transition through discharge heating. Thus, the present work shows that the primary effect of rf-power on the ring-mode to red-mode transition can be understood in terms of the radiation trapping mechanism.

  11. Deterministic source of a train of indistinguishable single-photon pulses with single-atom-cavity system

    E-Print Network [OSTI]

    A. Gogyan; S. Guérin; H. -R. Jauslin; Yu. Malakyan

    2010-05-01T23:59:59.000Z

    We present a mechanism to produce indistinguishable single-photon pulses on demand from an optical cavity. The sequences of two laser pulses generate, at the two Raman transitions of a four-level atom, the same cavity-mode photons without repumping of the atom between photon generations. Photons are emitted from the cavity with near-unit efficiency in well-defined temporal modes of identical shapes controlled by the laser fields. The second order correlation function reveals the single-photon nature of the proposed source. A realistic setup for the experimental implementation is presented.

  12. Solution Processed MoS2-PVA Composite for Sub-Bandgap Mode-Locking of a Wideband Tunable Ultrafast Er:Fiber Laser

    E-Print Network [OSTI]

    Zhang, Meng; Howe, Richard C. T.; Woodward, Robert I.; Kelleher, Edmund J. R.; Torrisi, Felice; Hu, Guohua; Popov, Sergei V.; Taylor, J. Roy; Hasan, Tawfique

    2014-11-11T23:59:59.000Z

    with stable, picosecond pulses, tunable from 1535 nm to 1565 nm 2 Solution Processed MoS2-PVA Composite for Sub-Bandgap Mode-Locking of a Wideband Tunable Ultrafast Er:Fiber Laser Meng Zhang1, Richard C. T. Howe2, Robert I. Woodward1... ! to! relaxation! of! thermalized! electron! and!phonon! distribution! [3].! This! combination! of!properties!makes!MoS2!a!suitable!saturable!absorber!(SA)! for! ultrafast! mode+locked! pulsed! lasers,! with!the! potential! for! pulse! generation! at...

  13. Pulsed electrodeposition of iron-nickel alloys

    SciTech Connect (OSTI)

    Grimmett, D.L.; Schwartz, M.; Nobe, K. (Dept. of Chemical Engineering, Univ. of California, Los Angeles, CA (US))

    1990-11-01T23:59:59.000Z

    This paper reports on the effects of dc, pulse, and pulse reverse current waveforms on deposition of Fe-Ni alloys studied in unagitated solutions and with a rotating cylindrical electrode. A nickel sulfamate/ferrous chloride electrolyte system at pH 2 less than 2 A/dm{sup 2}. Pulse reverse plating led to a decrease in anomalous deposition at low current densities. Rotating cylindrical electrodes indicated significant mass transfer effects at high current densities. During pulse reverse plating an increase in anodic pulse magnitude decreased anomalous deposition; pulse frequency had its greatest effect in reducing anomalous deposition between 100 and 300 Hz.

  14. Mode propagation and absorption loss in metal-clad periodic optical waveguides

    SciTech Connect (OSTI)

    Chunsheng Ma [Jilin Univ., Changchun (China)

    1996-02-01T23:59:59.000Z

    In terms of the mode eigenvalue equations are field distributions, calculations are performed for Au/InGaAsP/InP, air/Au/InGaAsP/InP, and Au/DiO{sub 2}InGaAsP/InP periodic optical waveguides. On the basis of the computed results, the coupling property in the periodic structure is analyzed, the mode split and the mode band formation of both TE and TM guided modes are described, and the effects of the thickness of the metal cladding and the oxide buffer layer on mode propagation and absorption loss are discussed for TE and TM guided modes as well as for the TM surface-plasma mode. Furthermore, the conversion from the surface-plasma wave to the guided wave for the TM mode is explained for Au/SiO{sub 2}/InGaAsP/InP periodic structures. 27 refs., 8 figs.

  15. Demonstration of coherent time-frequency Schmidt mode selection using dispersion-engineered frequency conversion

    E-Print Network [OSTI]

    Benjamin Brecht; Andreas Eckstein; Raimund Ricken; Viktor Quiring; Hubertus Suche; Linda Sansoni; Christine Silberhorn

    2014-09-16T23:59:59.000Z

    Time-frequency Schmidt (TFS) modes of ultrafast quantum states are naturally compatible with high bit-rate integrated quantum communication networks. Thus they offer an attractive alternative for the realization of high dimensional quantum optics. Here, we present a quantum pulse gate based on dispersion-engineered ultrafast frequency conversion in a nonlinear optical waveguide, which is a key element for harnessing the potential of TFS modes. We experimentally retrieve the modal spectral-temporal structure of our device and demonstrate a single-mode operation fidelity of 80\\%, which is limited by experimental shortcomings. In addition, we retrieve a conversion efficiency of 87.7\\% with a high signal-to-noise ratio of 8.8 when operating the quantum pulse gate at the single-photon level.

  16. Control of focusing fields in laser-plasma accelerators using higher-order modes E. Cormier-Michel,1,* E. Esarey,1

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    of intense laser pulses in plasma channels [1] has many applications, including x-ray lasers [2], highControl of focusing fields in laser-plasma accelerators using higher-order modes E. Cormier-order laser modes are analyzed as a method to control focusing forces and improve the electron bunch quality

  17. Mode Order Converter Using Tapered Multi-mode Interference Couplers

    E-Print Network [OSTI]

    Texas at Austin, University of

    , and modes of guided light is essential for flexibility in photonic integrated circuit (PIC) design.3120) Integrated optics devices; (130.2790) Guided waves 1. Introduction Accommodating various sizes, shapes indices. One can define Am0 as the transmission of the fundamental mode in the output guide when exciting

  18. Attosecond X-Ray Pulses for Molecular Electronic Dynamics

    E-Print Network [OSTI]

    Abel, Mark Joseph

    2010-01-01T23:59:59.000Z

    techniques for ultrafast laser pulse characterization. Thethe ultrafast evolution of the driver pulse intensity, weisolated pulse production will enable probing of ultrafast

  19. Cooperative pulses Technologieangebot /Technology offer

    E-Print Network [OSTI]

    on issues from the national and international research and technology transfer. To market the patentsCooperative pulses Technologieangebot /Technology offer Referenz /Reference 2010-04E04 Branche at the TUM TUM ForTe Forschungsförderung & Technologie- transfer Patent- und Lizenzbüro Arcisstra�e 2180333

  20. Novette pulse-power-system description

    SciTech Connect (OSTI)

    Gritton, D.G.; Christie, D.J.; Holloway, R.W.; Merritt, B.T.; Oicles, J.A.; Whitham, K.; Wilcox, R.B.

    1983-01-01T23:59:59.000Z

    This paper is a summary of the pulse power systems for Novette; the flashlamp power system, the pulsers for the various optical shutters and the pulse power control system.

  1. Voltage controlled MESFET pulse shape generator

    SciTech Connect (OSTI)

    Burkhart, S.C.

    1994-10-26T23:59:59.000Z

    A programmable pulse shape generator capable of producing pulse shapes for Nova and Beamlet has been designed and simulated using the circuit code SPICE. The design utilizes power MESFETS, which are commonly used in microwave amplifiers. The pulse shape is varied by setting a bias voltage on each in a chain of MESFETS with a 200 ps temporal resolution. The electrical pulse then drives an integrated electro-optic modulator similar to what is on Beamlet. Pulse shapes 22 and 25, used on Nova, have been generated by this design. There is no fundamental barrier to making such a pulse generator for use on the National Ignition Facility. In fact, the longer time scales on the NIF pulse will ease the high speed requirements of the pulse shape generator allowing the use of less expensive components. The next step will be to build a prototype circuit for initial testing on Beamlet and Nova.

  2. ULTRASHORT LASER PULSE PROPAGATION IN WATER

    E-Print Network [OSTI]

    Byeon, Joong-Hyeok

    2010-01-16T23:59:59.000Z

    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 (CW) obey the Beer...

  3. Dispersion compensation in chirped pulse amplification systems

    DOE Patents [OSTI]

    Bayramian, Andrew James; Molander, William A.

    2014-07-15T23:59:59.000Z

    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.

  4. ICE Pulse Oximeter Smart Alarm App Requirements

    E-Print Network [OSTI]

    Huth, Michael

    ICE Pulse Oximeter Smart Alarm App Requirements 6 March 2012 Revision 0 for an Integrated Clinical Environment (ICE) pulse oximetry monitoring app that provides.2 References [Purpose: List all ICE standards, and other standards and references

  5. 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

    2014-05-15T23:59:59.000Z

    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.

  6. Goldstone modes in Lyapunov spectra of hard sphere systems

    E-Print Network [OSTI]

    Astrid S. de Wijn; Henk van Beijeren

    2004-04-29T23:59:59.000Z

    In this paper, we demonstrate how the Lyapunov exponents close to zero of a system of many hard spheres can be described as Goldstone modes, by using a Boltzmann type of approach. At low densities, the correct form is found for the wave number dependence of the exponents as well as for the corresponding eigenvectors in tangent-space. The predicted values for the Lyapunov exponents belonging to the transverse mode are within a few percent of the values found in recent simulations, the propagation velocity for the longitudinal mode is within 1%, but the value for the Lyapunov exponent belonging to the longitudinal mode deviates from the simulations by 30%. For higher densities, the predicted values deviate more from the values calculated in the simulations. These deviations may be due to contributions from ring collisions and similar terms, which, even at low densities, can contribute to the leading order.

  7. Developing high energy mode-locked fiber laser at 2 micron

    E-Print Network [OSTI]

    Huang, C; Shang, W; Tang, Y; Xu, J

    2015-01-01T23:59:59.000Z

    While dissipative soliton operation has successfully improved the pulse energy of 1 {\\mu}m and 1.5 {\\mu}m fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy of dissipative solitons at 2 {\\mu}m due to the anomalous dispersion of the gain fiber. Based on theoretical simulation, we analyze intracavity dynamics of dissipative solitons (DSs) and propose that gain fiber should be condensed to short length in order to scale the pulse energy of 2 {\\mu}m DSs. The simulation predicts pulse energy of over 10 nJ for 2 {\\mu}m dissipative solitons, comparable to that achieved in the 1 {\\mu}m and 1.5 {\\mu}m regimes. Experimental operation generates stable 2 {\\mu}m DSs from a linear cavity with pulse energy of 4.9 nJ and dechirped pulse duration of 579 fs. These results advance our understanding of mode-locked fiber laser at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media at 2 {\\mu}m.

  8. Hawking radiation and Quasinormal modes

    E-Print Network [OSTI]

    SangChul Yoon

    2005-10-05T23:59:59.000Z

    The spectrum of Hawking radiation by quantum fields in the curved spacetime is continuous, so the explanation of Hawking radiation using quasinormal modes can be suspected to be impossible. We find that quasinormal modes do not explain the relation between the state observed in a region far away from a black hole and the short distance behavior of the state on the horizon.

  9. Mediating Religion: Modes of Communication

    E-Print Network [OSTI]

    Indiana University

    Mediating Religion: Modes of Communication in Religious Contexts Keynote: Dr. Lerone Martin, particularly given recent innovations in mass media and digital communications technologies. Turning attention to modes of communication in religious contexts, this conference will address ways in which mass media have

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

    SciTech Connect (OSTI)

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

    2008-05-01T23:59:59.000Z

    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.

  11. FRACTAL DIMENSION ESTIMATION: EMPIRICAL MODE DECOMPOSITION VERSUS WAVELETS

    E-Print Network [OSTI]

    Gonçalves, Paulo

    FRACTAL DIMENSION ESTIMATION: EMPIRICAL MODE DECOMPOSITION VERSUS WAVELETS Paulo Gonc¸alves INRIA, France. {firstname.lastname}@ens-lyon.fr ABSTRACT We address the problem of fractal dimension estimation motions. Index Terms-- fractal dimension, regularity exponents, wavelet transform, EMD 1. MOTIVATION

  12. Critical {delta}{sup '} for stability of viscoresistive tearing modes

    SciTech Connect (OSTI)

    Grasso, D.; Hastie, R. J.; Porcelli, F. [Burning Plasma Research Group, Dipartimento di Energetica, Politecnico di Torino, Torino (Italy); Tebaldi, C. [Burning Plasma Research Group, Dipartimento di Energetica, Politecnico di Torino, Torino (Italy); Dipartimento di Matematica, Politecnico di Torino, Torino (Italy)

    2008-07-15T23:59:59.000Z

    An analytic expression for the stability threshold of linear tearing modes is derived. The magnetized plasma is described in terms of a standard viscoresistive magnetohydrodynamic model. The analytic derivation requires an extension of the standard layer equation that represents an approximation of the full model in the vicinity of the reconnecting layer. The analytic result is checked against numerical simulations, showing excellent agreement.

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

    DOE Patents [OSTI]

    Holtom, Gary R. (Boston, MA)

    2012-03-06T23:59:59.000Z

    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.

  14. Development of the Long Pulse Negative Ion Source for ITER

    SciTech Connect (OSTI)

    Hemsworth, R.S.; Svensson, L.; Esch, H.P.L. de; Krylov, A.; Massmann, P. [Association EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, 13108 St Paul-lez-Durance (France); Boilson, D. [Association EURATOM-DCU, PRL/NCPST, Glasnevin, Dublin 13 (Ireland); Fanz, U. [Association EURATOM-IPP, Max-Planck-Institut fuer Plasmaphysik D-85748 Garching (Germany); Zaniol, B. [CONSORZIO RFX Association EURATOM-ENEA, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2005-04-06T23:59:59.000Z

    A model of the ion source designed for the neutral beam injectors of the International Thermonuclear Experimental Reactor (ITER), the KAMABOKO III ion source, is being tested on the MANTIS test stand at the DRFC Cadarache in collaboration with JAERI, Japan, who designed and supplied the ion source. The ion source is attached to a 3 grid 30 keV accelerator (also supplied by JAERI) and the accelerated negative ion current is determined from the energy deposited on a calorimeter located 1.6 m from the source.During experiments on MANTIS three adverse effects of long pulse operation were found: The negative ion current to the calorimeter is {approx_equal}50% of that obtained from short pulse operation Increasing the plasma grid (PG) temperature results in {<=}40% enhancement in negative ion yield, substantially below that reported for short pulse operation, {>=}100%. The caesium 'consumption' is up to 1500 times that expected.Results presented here indicate that each of these is, at least partially, explained by thermal effects. Additionally presented are the results of a detailed characterisation of the source, which enable the most efficient mode of operation to be identified.

  15. Response of C(60) and C(n) to ultrashort laser pulses

    E-Print Network [OSTI]

    Torralva, B.; Niehaus, TA; Elstner, M.; Suhai, S.; Frauenheim, T.; Allen, Roland E.

    2001-01-01T23:59:59.000Z

    reliable numerical simulations. 0163-1829/2001/64~15!/153105~4!/$20.00 64 153105- ultrashort laser pulses Suhai,2 Th. Frauenheim,3 and R. E. Allen1 Physics, College Station, Texas 77843 re Biophysik, D-69120 Heidelberg, Germany retische Physik, D...-33098 Paderborn, Germany d 22 June 2001; published 21 September 2001! s of nonadiabatic processes, including the e of C60 and carbon chains to laser pulses demon- . For example, in C60 the pentagonal-pinch mode t at high fluence, and dimers...

  16. RXTE observations of single pulses of PSR B0531+21: II Test for radio behavior

    E-Print Network [OSTI]

    M. Vivekanand

    2002-05-13T23:59:59.000Z

    This article is the second in the series that analyze about 1.87 million periods of Crab pulsar, observed by the PCA detector aboard the RXTE x-ray observatory. At these energies the pulsar displays none of the three phenomena that are often seen in normal radio pulsars -- ``pulse nulling'', ``systematic sub pulse drifting'' and ``mode changing''. Presence or absence of these three behavior in the Crab pulsar, at radio wavelengths, something that has not been rigorously established yet, might be important for a satisfactory understanding of the above three phenomena.

  17. CHEMICAL ENGINEERING Fall Term Spring Term

    E-Print Network [OSTI]

    Lee, Kelvin H.

    CHEMICAL ENGINEERING CURRICULUM FALL 2010 Fall Term Spring Term EGGG 101 Introduction to Chemical Engineering 3 MATH 242 Analytic Geometry & Calculus B 4 MATH 243 Analytic Geometry & Calculus C 4 Critical Reading and Writing 3 Breadth Requirement Elective 1 3 15 17 CHEG 231 Chemical Engineering

  18. CHEMICAL ENGINEERING Fall Term Spring Term

    E-Print Network [OSTI]

    Lee, Kelvin H.

    CHEG 332 Chemical Engineering Kinetics 3 CHEG 342 Heat and Mass Transfer 3 CHEG 341 Fluid Mechanics 3CHEMICAL ENGINEERING CURRICULUM Fall Term Spring Term EGGG 101 Introduction to Engineering (FYE) 2 CHEG 112 Introduction to Chemical Engineering 3 CHEM 111 General Chemistry 3 CHEM 112 General Chemistry

  19. Femtosecond pulse imaging: ultrafast optical oscilloscope

    E-Print Network [OSTI]

    Fainman, Yeshaiahu

    Femtosecond pulse imaging: ultrafast optical oscilloscope P. C. Sun, Y. T. Mazurenko,* and Y as well as our ability to detect the shape of the ul- trashort pulses that can be seen as an ultrafast 12, 1996 A nonlinear optical processor that is capable of real-time conversion of a femtosecond pulse

  20. High-Pulse-Energy Ultrafast Laser for

    E-Print Network [OSTI]

    Painter, Kevin

    High-Pulse-Energy Ultrafast Laser for Spectroscopy & Micromachining PROBLEM THIS TECHNOLOGY SOLVES. In addition to the OPO, a custom designed ultrafast pump source, provides high pulse energy (.res.hw.ac.uk Professor Derryck Reid (Principal Investigator) www.ultrafast.hw.ac.uk BENEFITS & APPLICATIONS: · High pulse

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

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

    Gerhardt, S. P. [Princeton Plasma Physics Laboratory; Canik, J. M. [ORNL; Maingi, R. [PPPL; Battaglia, D. [PPPL; Bell, R. E. [PPPL; Guttenfelder, W. [PPPL; LeBlanc, B. P. [PPPL; Smith, D. R. [U. Wisconsin-Madison; Yuh, H. [Nova Photonics; Sabbagh, S. [Columbia Univ

    2014-06-02T23:59:59.000Z

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

    SciTech Connect (OSTI)

    none,

    2014-06-26T23:59:59.000Z

    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.

  3. 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.

    2014-08-01T23:59:59.000Z

    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.

  4. Pulsed Power for Solid-State Lasers

    SciTech Connect (OSTI)

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

    2007-04-19T23:59:59.000Z

    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.

  5. Pulsed Power Driven Fusion Energy

    SciTech Connect (OSTI)

    SLUTZ,STEPHEN A.

    1999-11-22T23:59:59.000Z

    Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

  6. Unsplit bipolar pulse forming line

    DOE Patents [OSTI]

    Rhodes, Mark A. (Pleasanton, CA)

    2011-05-24T23:59:59.000Z

    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.

  7. 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)

    2001-01-01T23:59:59.000Z

    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.

  8. Ion Acceleration by Short Chirped Laser Pulses

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

    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.

  9. Adaptive control system for pulsed megawatt klystrons

    DOE Patents [OSTI]

    Bolie, Victor W. (Albuquerque, NM)

    1992-01-01T23:59:59.000Z

    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.

  10. Solid state pulsed power generator

    DOE Patents [OSTI]

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

    2014-02-11T23:59:59.000Z

    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.

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

    DOE Patents [OSTI]

    Bolton, Paul R. (Menlo Park, CA)

    1992-01-01T23:59:59.000Z

    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.

  12. Mode synthesizing atomic force microscopy and mode-synthesizing sensing

    DOE Patents [OSTI]

    Passian, Ali; Thundat, Thomas George; Tetard, Laurene

    2013-05-17T23:59:59.000Z

    A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

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

    E-Print Network [OSTI]

    Skadron, Kevin

    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

  14. Bearing Fault Detection in DFIG-Based Wind Turbines Using the First Intrinsic Mode Function

    E-Print Network [OSTI]

    Boyer, Edmond

    Bearing Fault Detection in DFIG-Based Wind Turbines Using the First Intrinsic Mode Function Y for bearing fault detection in DFIG-based wind turbines. The proposed method uses the first Intrinsic Mode Terms--Wind turbine, Doubly Fed Induction Generator (DFIG), fault detection, bearings, signal processing

  15. Peeling mode relaxation ELM model

    SciTech Connect (OSTI)

    Gimblett, C. G. [EURATOM/UKAEA Fusion Association, Culham Science Centre Abingdon, Oxon, OX14 3DB (United Kingdom)

    2006-11-30T23:59:59.000Z

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made.

  16. Existence of Metastable Kinetic Modes

    SciTech Connect (OSTI)

    Nguyen, C.; Luetjens, H.; Garbet, X.; Grandgirard, V.; Lesur, M. [Centre de Physique Theorique, CNRS-Ecole Polytechnique, Palaiseau (France); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); JAEA, Higashi-Ueno 6-9-3, Taitou, Tokyo, 110-0015 (Japan)

    2010-11-12T23:59:59.000Z

    The nonlinear evolution of resonantly driven systems, such as suprathermal particle driven modes in magnetically confined plasmas, is shown to strongly depend on the existence and nature of an underlying damping mechanism. When background resonant damping is present, subcritical states can take place. In particular, purely nonlinear steady-state regimes are found, whose destabilization threshold and saturation levels are calculated and validated using numerical simulations. This nonlinear behavior can be of relevance for acoustic modes in magnetically confined plasmas.

  17. Phase space theory of Bose-Einstein condensates and time-dependent modes

    E-Print Network [OSTI]

    B. J. Dalton

    2012-07-20T23:59:59.000Z

    A phase space theory approach for treating dynamical behaviour of Bose-Einstein condensates applicable to situations such as interferometry with BEC in time-dependent double well potentials is presented. Time-dependent mode functions are used, chosen so that one, two,.. highly occupied modes describe well the physics of interacting condensate bosons in time dependent potentials at well below the transition temperature. Time dependent mode annihilation, creation operators are represented by time dependent phase variables, but time independent total field annihilation, creation operators are represented by time independent field functions. Two situations are treated, one (mode theory) is where specific mode annihilation, creation operators and their related phase variables and distribution functions are dealt with, the other (field theory) is where only field creation, annihilation operators and their related field functions and distribution functionals are involved. The paper focuses on the hybrid approach, where the modes are divided up between condensate (highly occupied) modes and non-condensate (sparsely occupied) modes. It is found that there are extra terms in the Ito stochastic equations both for the stochastic phases and stochastic fields, involving coupling coefficients defined via overlap integrals between mode functions and their time derivatives. For the hybrid approach both the Fokker-Planck and functional Fokker-Planck equations differ from those derived via the correspondence rules, the drift vectors are unchanged but the diffusion matrices contain additional terms involving the coupling coefficients. Results are also presented for the combined approach where all the modes are treated as one set.

  18. 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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - SeptemberMicroneedlesAdvancedJanuary 13, 2011

  19. Operation conditions for a picosecond laser with an aberration thermal lens under longitudinal pulsed diode pumping

    SciTech Connect (OSTI)

    Morozov, V B; Olenin, A N; Tunkin, V G; Yakovlev, D V

    2011-06-30T23:59:59.000Z

    The dependence of the repetition frequency range that provides stable operation of a picosecond laser with longitudinal pulsed diode pumping on the parameters of the laser cavity and the thermal lens induced in the active element is analysed. The results of calculating the radius of the lower cavity mode as a function of pump beam average power and diameter are reported. Based on the measurements by the probe-beam method, the adequacy of the presented model of aberration thermal lens is demonstrated for the cases of uniformly doped Nd:YAG and composite YAG/Nd:YAG active elements upon tuning the pump pulse repetition frequency within the range of 0 - 1 kHz. The ways for implementing stable generation of millijoule pulses in a specified repetition frequency range are discussed. (control of laser radiation parameters)

  20. Efficient Photoionization-Loading of Trapped Cadmium Ions with Ultrafast Pulses

    E-Print Network [OSTI]

    L. Deslauriers; M. Acton; B. B. Blinov; K. -A. Brickman; P. C. Haljan; W. K. Hensinger; D. Hucul; S. Katnik; R. N. Kohn, Jr.; P. J. Lee; M. J. Madsen; P. Maunz; S. Olmschenk; D. L. Moehring; D. Stick; J. Sterk; M. Yeo; K. C. Younge; C. Monroe

    2006-08-04T23:59:59.000Z

    Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:Sapphire laser that produces pulses of either 100 fsec or 1 psec duration at a central wavelength of 229 nm. The large bandwidth of the pulses photoionizes all velocity classes of the Cd vapor, resulting in high loading efficiencies compared to previous ion trap loading techniques. Measured loading rates are compared with a simple theoretical model, and we conclude that this technique can potentially ionize every atom traversing the laser beam within the trapping volume. This may allow the operation of ion traps with lower levels of background pressures and less trap electrode surface contamination. The technique and laser system reported here should be applicable to loading most laser-cooled ion species.

  1. A Pulsational Model for the Orthogonal Polarization Modes in Radio Pulsars

    E-Print Network [OSTI]

    J. Christopher Clemens; R. Rosen

    2008-02-17T23:59:59.000Z

    In an earlier paper, we introduced a model for pulsars in which non-radial oscillations of high spherical degree (\\el) aligned to the magnetic axis of a spinning neutron star were able to reproduce subpulses like those observed in single-pulse measurements of pulsar intensity. The model did not address polarization, which is an integral part of pulsar emission. Observations show that many pulsars emit radio waves that appear to be the superposition of two linearly polarized emission modes with orthogonal polarization angles. In this paper, we extend our model to incorporate linear polarization. As before, we propose that pulsational displacements of stellar material modulate the pulsar emission, but now we apply this modulation to a linearly-polarized mode of emission, as might be produced by curvature radiation. We further introduce a second polarization mode, orthogonal to the first, that is modulated by pulsational velocities. We combine these modes in superposition to model the observed Stokes parameters in radio pulsars.

  2. Occupant satisfaction in mixed-mode buildings.

    E-Print Network [OSTI]

    Brager, Gail; Baker, Lindsay

    2008-01-01T23:59:59.000Z

    Strategies for Mixed-Mode Buildings, Summary Report, CenterCBE). 2006. Website: Mixed-Mode Building Case Studies.Department of Environmental Building Research Establishment

  3. Occupant satisfaction in mixed-mode buildings

    E-Print Network [OSTI]

    Brager, Gail; Baker, Lindsay

    2009-01-01T23:59:59.000Z

    Environmental Quality in Green Buildings”. Indoor Air; 14 (Strategies for Mixed-Mode Buildings, Summary Report, CenterCBE). 2006. Website: Mixed-Mode Building Case Studies.

  4. Development of an Ultra High Frequency Gyrotron with a Pulsed Magnet

    SciTech Connect (OSTI)

    Idehara, T.; Kamada, M.; Tsuchiya, H.; Hayashi, T.; Agusu, La; Mitsudo, S.; Ogawa, I. [Research Center for Development of Far Infrared Region, University of Fukui, Bunkyo 3-9-1, Fukui-shi 910-8507 (Japan); Manuilov, V. N. [Research Center for Development of Far Infrared Region, University of Fukui, Bunkyo 3-9-1, Fukui-shi 910-8507 (Japan); Radiophysical Department of Nizhny Novgorod State University, 690005, Gagarin av., 23, Nizhny Novgorod (Russian Federation); Naito, K.; Yuyama, T.; Jiang, W.; Yatsui, K. [Extreme Energy-Density Research Institute, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka-shi, Niigata 940-2188 (Japan)

    2006-01-03T23:59:59.000Z

    An ultra-high frequency gyrotron is being developed as a THz radiation source by using a pulsed magnet. We have achieved the highest field intensity of 20.2 T. High frequency operation at the second harmonic will achieve 1.01 THz; the corresponding cavity mode is TE6,11,1. On the other hand, an ultra-high power gyrotron with a pulsed magnet is also being developed as a millimeter to submillimeter wave radiation source. The gyrotron is a large orbit gyrotron (LOG) using an intense relativistic electron beam (IREB). A pulsed power generator 'ETIGO-IV' is applied for generation of the IREB. A prototype relativistic LOG was constructed for fundamental operation. The output of the LOG will achieve 144 GHz and 9 MW; the corresponding cavity mode is TE1,4,1. Cavities for 2nd and 4th harmonic operations were designed by numerical simulation for achievement of higher frequency. The progress of development for prototype high frequency gyrotrons with pulsed magnets is presented.

  5. 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)

    2001-01-01T23:59:59.000Z

    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.

  6. Two-pulse stimulated echo in magnets

    E-Print Network [OSTI]

    Zviadadze, M D; Gegechkori, T O; Akhalkatsi, A M; Gavasheli, T A

    2012-01-01T23:59:59.000Z

    The results of experimental study of two-pulse stimulated echo in ferromagnets of two types are presented. Ferromagnet Co and half-metal Co MnSi 2, in which a single-pulse echo formed by the distortion mechanism of the fronts of exciting pulse is also observed, are classified among the first type. Lithium ferrite and intermetal compound MnSb characterized by the absence of single-pulse echo in them - belong to the second type. For signals of two-pulse stimulated echo in the materials of the first type a short time and a long time of relaxations are observed. The short time is about the order of value shorter less than the spin-spin relaxation time. The long time is close to the transverse relaxation time of single-pulse echo formed by the distortion mechanism. The mechanisms that provide the possible interpretations of the peculiarities of the processes of nuclear magnetic relaxation are discussed.

  7. Pulsed source ion implantation apparatus and method

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA)

    1996-01-01T23:59:59.000Z

    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.

  8. PULSE DRYING EXPERIMENT AND BURNER CONSTRUCTION

    SciTech Connect (OSTI)

    Robert States

    2006-07-15T23:59:59.000Z

    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.

  9. Pulsed source ion implantation apparatus and method

    DOE Patents [OSTI]

    Leung, K.N.

    1996-09-24T23:59:59.000Z

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

    E-Print Network [OSTI]

    Gevorg Muradyan; A. Zh. Muradyan

    2009-08-21T23:59:59.000Z

    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.

  11. bia-pulse | netl.doe.gov

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

    4 Industrial Carbon Capture and Storage Clean Coal Power Initiative Power Plant Improvement Initiative Clean Coal Technology Demonstration Program FutureGen Pulse Combustor Design...

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

    E-Print Network [OSTI]

    D. M. Hoyle; S. M. Fielding

    2015-01-07T23:59:59.000Z

    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.

  13. 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.

    2010-01-01T23:59:59.000Z

    , M. Elstner, S. Suhai, Th. Frauen- heim, and R. E. Allen, Phys. Rev. B 64, 153105 #1;2001#2;. 12 G. P. Zhang and T. F. George, Phys. Rev. Lett. 93, 147401 #1;2004#2;; Phys. Rev. B 73, 035422 #1;2006#2;. 13 U. Banin, A. Bartana, S. Ruhman, and R...

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

    E-Print Network [OSTI]

    Chung, Kiwhan

    2009-05-15T23:59:59.000Z

    ........................................ 60 9 Top view of detector matrix for simulation setup...................................... 61 10 HDPE thickness optimization .................................................................... 62 11 Performance of matrix detector... Nonproliferation of the National Nuclear Security Administration (NNSA, 2004) states, ?Detects nuclear proliferation and illicit nuclear and radiological trafficking by conducting cutting-edge research and development?.? More specifically, the need for a neutron...

  15. Polarization Properties of A Multi-Moded Concentrator

    E-Print Network [OSTI]

    Kogut, A; Hill, R S

    2015-01-01T23:59:59.000Z

    We present the design and performance of a non-imaging concentrator for use in broad-band polarimetry at millimeter through submillimeter wavelengths. A rectangular geometry preserves the input polarization state as the concentrator couples f/2 incident optics to a 2 pi sr detector. Measurements of the co-polar and cross-polar beams in both the few-mode and highly over-moded limits agree with a simple model based on mode truncation. The measured co-polar beam pattern is nearly independent of frequency in both linear polarizations. The cross-polar beam pattern is dominated by a uniform term corresponding to polarization efficiency 94%. After correcting for efficiency, the remaining cross-polar response is -18 dB.

  16. Brief Communication High temperature pulses decrease indirect chilling injury and elevate ATP levels

    E-Print Network [OSTI]

    Lee Jr., Richard E.

    Brief Communication High temperature pulses decrease indirect chilling injury and elevate ATP: Received 20 December 2009 Accepted 8 March 2010 Available online 15 March 2010 Keywords: ATP Energy supply by determining survival rates and ATP levels for flies that had undergone continuous long-term exposure at 0 °C

  17. Preliminary Pulsing Experiments to Measure Delayed Neutron Emission Parameters

    SciTech Connect (OSTI)

    Charlton, W.S.; Parish, T.A.; Raman, S.

    1998-10-05T23:59:59.000Z

    Recent interest in delayed neutron parameters including comparisons between macroscopic (experimental) and microscopic (calculated) results have prompted a set of experiments using the 1MW Triga Reactor at the Texas A and M University (TAMU) Nuclear Science Center (NSC) designed to measure the complete set of seven-group delayed neutron parameters for several higher actinides. Operating the Nuclear Science Center Reactor (NSCR) in a pulsed mode, a complete set of delayed neutron parameters were measured for Np-237 and Am-243. The total delayed neutron yield per 100 fissions for Np-237 and Am-243 was found to be 1.14 {+-} 0.07 and 0.85 {+-} 0.05, respectively. Comparisons to previous measurements are made where such measurements are available.

  18. 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 Performance (perfSONAR) Software & Tools Development Partnerships...

  19. Response of the Hodgkin-Huxley neuron to a periodic sequence of biphasic pulses

    E-Print Network [OSTI]

    Borkowski, L S

    2013-01-01T23:59:59.000Z

    We study the response of the Hodgkin-Huxley neuron stimulated periodically by biphasic rectangular current pulses. The optimal response for charge-balanced input is obtained for cathodic-first pulses with an inter-phase gap (IPG) approximately equal 5 ms. For short pulses the topology of the global bifurcation diagram in the period-amplitude plane is approximately invariant with respect to the pulse polarity and shape details. If stimuli are delivered at neuron's resonant frequencies the firing rate is a continuous function of pulse amplitude. At nonresonant frequencies the quiescent state and the firing state coexist over a range of amplitude values and the transition to excitability is a discontinuous one. There is a multimodal odd-all transition between the 2:1 and 3:1 locked-in states. A strong antiresonant effect is found between the states 3:1 and 4:1, where the modes (2+3n):1, $n=0,1,2,...$, are entirely absent. At high frequencies the excitation threshold is a nonmonotonic function of the stimulus and...

  20. Broadband low-dispersion diffraction of femtosecond pulses

    E-Print Network [OSTI]

    Purdue University

    with that of a 100-fs pulse, which is ap- proximately 10 nm (or 5 THz) at 800 nm. The large bandwidths of ultrafast-bit-rate communications.12 Pulse shaping and control of ultrafast pulses are of interest not only from the practical point for femtosecond pulse shaping and ultrafast pulse switch- ing. Bandgap engineered broadband semiconductor MQW

  1. Laser system using ultra-short laser pulses

    DOE Patents [OSTI]

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

    2009-10-27T23:59:59.000Z

    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.

  2. 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)

    2014-06-15T23:59:59.000Z

    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.

  3. Stability of the splay state in pulse-coupled networks

    SciTech Connect (OSTI)

    Zillmer, Ruediger [Istituto dei Sistemi Complessi, CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Laboratoire de neurophysique et de physiologie du systeme moteur, CNRS-EP 1848, 45 Rue des Saints-Peres, 75270 Paris (France); INFN Sez. Firenze, via Sansone, 1-I-50019 Sesto Fiorentino (Italy); Livi, Roberto [Dipartimento di Fisica, Universita di Firenze, and Unita INFM via Sansone, 1-I-50019 Sesto Fiorentino (Italy); INFN Sez. Firenze, via Sansone, 1-I-50019 Sesto Fiorentino (Italy); Centro Interdipartimentale per lo Studio delle Dinamiche Complesse, via Sansone, 1-I-50019 Sesto Fiorentino (Italy); Politi, Antonio [Istituto dei Sistemi Complessi, CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Centro Interdipartimentale per lo Studio delle Dinamiche Complesse, via Sansone, 1-I-50019 Sesto Fiorentino (Italy); Torcini, Alessandro [Istituto dei Sistemi Complessi, CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); INFN Sez. Firenze, via Sansone, 1-I-50019 Sesto Fiorentino (Italy); Centro Interdipartimentale per lo Studio delle Dinamiche Complesse, via Sansone, 1-I-50019 Sesto Fiorentino (Italy)

    2007-10-15T23:59:59.000Z

    The stability of the dynamical states characterized by a uniform firing rate (splay states) is analyzed in a network of globally coupled leaky integrate-and-fire neurons. This is done by reducing the set of differential equations to a map that is investigated in the limit of large network size. We show that the stability of the splay state depends crucially on the ratio between the pulse width and the interspike interval. More precisely, the spectrum of Floquet exponents turns out to consist of three components: (i) one that coincides with the predictions of the mean-field analysis [Abbott and van Vreesvijk, Phys. Rev. E 48, 1483 (1993)], (ii) a component measuring the instability of 'finite-frequency' modes, (iii) a number of 'isolated' eigenvalues that are connected to the characteristics of the single pulse and may give rise to strong instabilities (the Floquet exponent being proportional to the network size). Finally, as a side result, we find that the splay state can be stable even for inhibitory coupling.

  4. 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. [Oak Ridge National Laboratory, 1Bethel Valley Rd Oak Ridge, TN 37831 (United States)

    2014-01-29T23:59:59.000Z

    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.

  5. High reliability low jitter pulse generator

    DOE Patents [OSTI]

    Savage, Mark E.; Stoltzfus, Brian S.

    2013-01-01T23:59:59.000Z

    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.

  6. Heart Physiology Lab Part 1: Pulse Rate

    E-Print Network [OSTI]

    Loughry, Jim

    Heart Physiology Lab Part 1: Pulse Rate Measure your pulse in each of the following conditions (in in the class. You may use Table 1 in the Heart Physiology Worksheet for this, if you wish. Once you have all of the class averages for each measurement. You may use Graph 1 in the Heart Physiology Worksheet for this

  7. Stably operating pulse combustor and method

    DOE Patents [OSTI]

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

    1990-01-01T23:59:59.000Z

    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.

  8. Coherence as ultrashort pulse train generator

    E-Print Network [OSTI]

    Gevorg Muradyan; Mariam Hovhannisyan

    2010-07-08T23:59:59.000Z

    Intense, well-controlled regular light pulse trains start to play a crucial role in many fields of physics. We theoretically demonstrate a very simple and robust technique for generating such periodic ultrashort pulses from a continuous probe wave which propagates in a dispersive thermal gas media.

  9. 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

  10. Strong excitation of emitters in an impedance matched cavity: the area theorem, ?-pulse and self-induced transparency

    E-Print Network [OSTI]

    Thierry Chanelière

    2014-02-16T23:59:59.000Z

    I theoretically study the behavior of strong pulses exciting emitters inside a cavity. The ensemble is supposed to be inhomogeneously broadened and the cavity matched finding application in quantum storage of optical or RF photons. My analysis is based on energy and pulse area conservation rules predicting important distortions for specific areas. It is well supported by numerical simulations. I propose a qualitative interpretation in terms of slow-light. The analogy with the free space situation is remarkable.

  11. Synchronization Techniques for Burst-Mode Continuous Phase Modulation

    E-Print Network [OSTI]

    Hosseini, Ehsan

    2013-12-31T23:59:59.000Z

    .12 BER for the burst-mode CPM receiver. L0 is the preamble length in terms of data symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 4.1 Phase response q(t) for SOQPSK-MIL (L = 1) and SOQPSK-TG (L = 8). . . . . 86 4.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 4.5 The computer search results for optimum training sequence for SOQPSK-MIL when L0 = 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 xii 4.6 The unwrapped phase response of SOQPSK-MIL and SOQPSK-TG schemes...

  12. Single-mode nonclassicality criteria via Holstein-Primakoff transformation

    E-Print Network [OSTI]

    Tasgin, Mehmet Emre

    2015-01-01T23:59:59.000Z

    Recently, two quantifications for nonclassicality of a single-mode field are shown to be equivalent; (i) the rank of entanglement it can generate by a beam-splitter and (ii) the number of terms needed to expand it as superposition of coherent states. We show that nonclassicality criteria can be obtained with an alternative approach. The rank of two-mode entanglement among 2-level identical particles converges to the rank of single-mode nonclassicality within the Holstein-Primakoff transformation, at the large particle number limit. In particular, we show that the entanglement criterion of Hillery & Zubairy converges to the Mandel's $Q$-parameter which is used to reveal nonclassicality, and spin-squeezing criterion of S{\\o}rensen et al. converges to single-mode squeezing condition. We obtain additional nonclassicality criteria not existing in the literature. We also discuss if single-mode nonclassicality can be visualized as the entanglement of space generating the photons. Moreover, in a forthcoming study...

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

    SciTech Connect (OSTI)

    Marceau, Claude, E-mail: claude.marceau.2@ulaval.ca; Thomas, Steven; Kassimi, Yacine; Gingras, Guillaume; Witzel, Bernd [Centre d'Optique, Photonique et Laser, Pavillon d'optique-photonique Québec (Québec), Université Laval, Québec G1V 0A6 (Canada)

    2014-02-03T23:59:59.000Z

    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.

  14. Digital gate pulse generator for cycloconverter control

    DOE Patents [OSTI]

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

    1989-01-01T23:59:59.000Z

    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. 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

    2009-06-22T23:59:59.000Z

    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.

  16. Ultrafast Pulse Shaping Approaches to Quantum Computing

    E-Print Network [OSTI]

    Debabrata Goswami

    2003-12-24T23:59:59.000Z

    Quantum computing exploits the quantum-mechanical nature of matter to exist in multiple possible states simultaneously. This new approach promises to revolutionize the present form of computing. As an approach to quantum computing, we discuss ultrafast laser pulse shaping, in particular, the acousto-optic modulator based Fourier-Transform pulse-shaper, which has the ability to modulate tunable high power ultrafast laser pulses. We show that optical pulse shaping is an attractive route to quantum computing since shaped pulses can be transmitted over optical hardware and the same infrastructure can be used for computation and optical information transfer. We also address the problem of extending coherence-times for optically induced processes.

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

    DOE Patents [OSTI]

    Fasching, George E. (Morgantown, WV)

    1987-01-01T23:59:59.000Z

    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.

  18. Ultrafast optical pulse shaping: A tutorial review Andrew M. Weiner

    E-Print Network [OSTI]

    Purdue University

    Ultrafast optical pulse shaping: A tutorial review Andrew M. Weiner Purdue University, School 2011 Keywords: Ultrafast optics Pulse shaping Femtosecond optics Coherent control Optical signal programmable reshapingof ultrafast pulses, or generation of arbitrary optical waveforms, according to user

  19. Information processing with longitudinal spectral decomposition of ultrashort pulses

    E-Print Network [OSTI]

    Saperstein, Robert Elliot

    2007-01-01T23:59:59.000Z

    decomposition of ultrafast pulses,” Appl. Opt. , doc. IDdecomposition of ultrafast pulses,” Appl. Opt. 47, A21-A31 (decomposition of ultrafast pulses,” Appl. Opt. 47, A21-A31 (

  20. The galactic double-mode Cepheids I. Frequency analysis of the light curves and comparison with single-mode Cepheids

    E-Print Network [OSTI]

    Ennio Poretti; Ilaria Pardo

    1996-12-05T23:59:59.000Z

    We submitted the available photometric V data of all the known galactic Double Mode Cepheids (DMCs) to a careful frequency analysis with the aim of detecting in each case the importance of the harmonics and of the cross coupling terms. For each object, starting from different data subsets, we progressively built a homogenous set of data, checking the consistency of the results step by step. It was demonstrated that each star displays a different content, showing that no a priori fit can be applied. Up to 4 harmonics were found for the fundamental radial mode (F); in every case, 2 harmonics were found for the first overtone radial mode (1 O). We also proceeded to a preliminar analysis of the Fourier parameters of the DMC light curves and we found a very close similarity between i) the light curves of the Classical Cepheids and those of the F-mode of the DMCs; ii) the light curves of the s-Cepheids and those of the 1 O-mode of the DMCs. The analysis of DMC light curves offers the possibility of unifying the light curves of Classical and s-Cepheids. The case of the unique DMC CO Aur is also discussed.

  1. Complete radiative terms for the electron/electronic energy equation

    SciTech Connect (OSTI)

    Stanley, S.A.; Carlson, L.A. [Univ of California, San Diego, CA (United States)

    1994-10-01T23:59:59.000Z

    A derivation of the radiative terms in the electron/electronic energy equation is presented, properly accounting for the effects of absorption and emission of radiation on the individual energy modes of the gas. This electron/electronic energy equation with the complete radiative terms has successfully been used to model the radiation-dominated precursor ahead of the bow shock of a hypersonic vehicle entering the Earth`s atmosphere. 8 refs.

  2. Applications of pulsed EPR spectroscopy to structural studies...

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

    pulsed EPR spectroscopy to structural studies of sulfite oxidizing enzymes. Applications of pulsed EPR spectroscopy to structural studies of sulfite oxidizing enzymes. Abstract:...

  3. Document Type: Subject Terms

    E-Print Network [OSTI]

    Major, Arkady

    Title: Authors: Source: Document Type: Subject Terms: Abstract: Full Text Word Count: ISSN at creating team results. In fact, it's priceless. Managers in Western corporations have received a lifetime

  4. Vibrational Modes of Adsorbed Atoms

    E-Print Network [OSTI]

    LAWRENCE, WR; Allen, Roland E.

    1977-01-01T23:59:59.000Z

    , because the interaction. a d t ion is weak corn pared to the Ne-A , n the 11. and ].~m ' w e 1V mode. modes lie below the In comparisons with the mass-def y eing a measure of the mass divided C. Ne on Kr The three" rin"p incipal surface mod... represe~t~~g lo or izontal" polari- 0 P) 0 CU 0 2v 1H 1L 4H e - XENON FIG. 1. Dimens' are ni nsionless f nine substrate requency (d* o- ' 'o a layers b vs two- d b 1 I" ng y try ' o He on Xe. There 15 5081 5082 R LA%REN C E AND R . E...

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

    DOE Patents [OSTI]

    Skupsky, Stanley (Rochester, NY); Kessler, Terrance J. (Rochester, NY); Letzring, Samuel A. (Honeoye Falls, NY)

    1993-01-01T23:59:59.000Z

    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.

  6. 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.

    1993-11-16T23:59:59.000Z

    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.

  7. 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)

    1999-12-28T23:59:59.000Z

    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.

  8. 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)

    2001-01-01T23:59:59.000Z

    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.

  9. Quantum simulation of Dirac fermion mode, Majorana fermion mode and Majorana-Weyl fermion mode in cavity QED lattice

    E-Print Network [OSTI]

    Sujit Sarkar

    2014-09-11T23:59:59.000Z

    Quantum simulation aims to simulate a quantum system using a controble laboratory system that underline the same mathematical model. Cavity QED lattice system is that prescribe system to simulate the relativistic quantum effect. We quantum simulate the Dirac fermion mode, Majorana fermion mode and Majorana-Weyl fermion mode and a crossover between them in cavity QED lattice. We also present the different analytical relations between the field operators for different mode excitations.

  10. Real-time multi-mode neutron multiplicity counter

    DOE Patents [OSTI]

    Rowland, Mark S; Alvarez, Raymond A

    2013-02-26T23:59:59.000Z

    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.

  11. 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

    2013-01-01T23:59:59.000Z

    electrical stimulation pulse trains as a function of pulseelectrical stimulation pulse trains as a function of pulsestimulation parameters (train duration, interpulse interval,

  12. 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

    2014-08-05T23:59:59.000Z

    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.

  13. Ultrafast Optical Pulses: Synthesis and Applications

    E-Print Network [OSTI]

    Wang, Kai

    2013-12-11T23:59:59.000Z

    This dissertation is devoted to ultrafast waveform synthesis using coherent Raman sidebands with the assistance of pulse shapers based on acousto-optic programmable dispersive ?lter (AOPDF) or deformable mirror (DM). Ultrashort optical science has...

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

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

    Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. lm015smith2010o.pdf More Documents & Publications Pulse-Pressure Forming of Lightweight Metals...

  15. Electromagnetic or other directed energy pulse launcher

    DOE Patents [OSTI]

    Ziolkowski, Richard W. (Livermore, CA)

    1990-01-01T23:59:59.000Z

    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.

  16. Broadband frequency mode entanglement in waveguided PDC

    E-Print Network [OSTI]

    Andreas Eckstein; Christine Silberhorn

    2008-07-04T23:59:59.000Z

    We report the observation of beatings of the coincidence event rate in a Hong-Ou-Mandel interference (HOMI) between signal and idler photons from a parametric downconversion (PDC) process inside a multi-mode KTP waveguide. As explanation we introduce bi-photonic states entangled in their broadband frequency modes generated by waveguide mode triples and propose a suitable entanglement detection scheme.

  17. Detection of Tones and Pulses using a Large, Uncalibrated Array S.W. Ellingson

    E-Print Network [OSTI]

    Ellingson, Steven W.

    ]; and wide- band pulses associated with (for example) gamma ray bursts [2] and intermittent "giant pulses

  18. Tunable pulsed narrow bandwidth light source

    DOE Patents [OSTI]

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

    2002-01-01T23:59:59.000Z

    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.

  19. Pulse width modulation inverter with battery charger

    DOE Patents [OSTI]

    Slicker, James M. (Union Lake, MI)

    1985-01-01T23:59:59.000Z

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  20. Nonlinear evolution of the resistive interchange mode in the cylindrical spheromak

    SciTech Connect (OSTI)

    DeLucia, J.; Jardin, S.C.

    1984-02-01T23:59:59.000Z

    Results are presented of a study of various aspects of the single helicity nonlinear development of the resistive interchange mode in the cylindrical spheromak. A formulation of the helically symmetric resistive MHD equations that partially separates the ideal MHD characteristics is developed. Mode saturation can occur due to the quasilinear flattening of the pressure profile in the vicinity of the mode rational surface. However, this saturation process is defeated when the plasma overheats and in regions of the plasma where the shear is low. Finite fluid compression has significant, and optimistic, consequences on the long-term nonlinear behavior of this mode. For a tearing mode stable cylindrical spheromak equilibrium configuration with an axial beta value of 6%, complete overlap of the m = 1 islands occurs in about 3% of the resistive skin time for a magnetic Reynold's number of S = 10/sup 5/. For typical parameters of the S-1 device at Princeton, this time corresponds to nearly one-millisecond.

  1. Fundamental oscillation modes of neutron stars: validity of universal relations

    E-Print Network [OSTI]

    Chirenti, Cecilia; Kastaun, Wolfgang

    2015-01-01T23:59:59.000Z

    We study the $f$-mode frequencies and damping times of nonrotating neutron stars (NS) in general relativity (GR) by solving the linearized perturbation equations, with the aim to establish "universal" relations that depend only weakly on the equations of state (EOS). Using a more comprehensive set of EOSs, we re-examine some proposed linearizations that describe the $f$-mode parameters in terms of mass and radius of the neutron star (NS), and we test a more recent proposal for expressing the $f$-mode parameters as quadratic functions of the effective compactness. Our extensive results for each equation of state considered allow us to study the accuracy of each proposal. In particular, we find that the damping time deviates quite considerably from the proposed linearization. We introduce a new universal relation for the product of the $f$-mode frequency and damping time as a function of the (ordinary) compactness, which proved to be more accurate. The relations using the effective compactness on the other hand...

  2. 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)

    2014-07-28T23:59:59.000Z

    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.

  3. Pulsed, Photonuclear-induced, Neutron Measurements of Nuclear Materials with Composite Shielding

    SciTech Connect (OSTI)

    James Jones; Kevin Haskell; Rich Waston; William Geist; Jonathan Thron; Corey Freeman; Martyn Swinhoe; Seth McConchie; Eric Sword; Lee Montierth; John Zabriskie

    2011-07-01T23:59:59.000Z

    Active measurements were performed using a 10-MeV electron accelerator with inspection objects containing various nuclear and nonnuclear materials available at the Idaho National Laboratory’s Zero Power Physics Reactor (ZPPR) facility. The inspection objects were assembled from ZPPR reactor plate materials to evaluate the measurement technologies for the characterization of plutonium, depleted uranium or highly enriched uranium shielded by both nuclear and non-nuclear materials. A series of pulsed photonuclear, time-correlated measurements were performed with unshielded calibration materials and then compared with the more complex composite shield configurations. The measurements used multiple 3He detectors that are designed to detect fission neutrons between pulses of an electron linear accelerator. The accelerator produced 10-MeV bremsstrahlung X-rays at a repetition rate of 125 Hz (8 ms between pulses) with a 4-us pulse width. All inspected objects were positioned on beam centerline and 100 cm from the X-ray source. The time-correlated data was collected in parallel using both a Los Alamos National Laboratory-designed list-mode acquisition system and a commercial multichannel scaler analyzer. A combination of different measurement configurations and data analysis methods enabled the identification of each object. This paper describes the experimental configuration, the ZPPR inspection objects used, and the various measurement and analysis results for each inspected object.

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

    SciTech Connect (OSTI)

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

    1984-12-01T23:59:59.000Z

    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)

  5. Mode analysis of photonic crystal L3 cavities in self-suspended lithium niobate membranes

    SciTech Connect (OSTI)

    Diziain, Séverine, E-mail: severine.diziain@uni-jena.de; Geiss, Reinhard; Zilk, Matthias; Schrempel, Frank; Kley, Ernst-Bernhard; Pertsch, Thomas [Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany)] [Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Tünnermann, Andreas [Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany) [Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Fraunhofer Institute for Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, 07745 Jena (Germany)

    2013-12-16T23:59:59.000Z

    We report on a multimodal analysis of photonic crystal L3 cavities milled in lithium niobate free-standing membranes. The classical L3 cavity geometry is compared to an L3 cavity containing a second lattice superimposed on the primary one. Those two different geometries are investigated in terms of vertical radiation and quality (Q) factor for each mode of the cavities. Depending on the cavity geometry, some modes undergo an enhancement of their vertical radiation into small angles while other modes experience a higher Q factor. Experimental characterizations are corroborated by three-dimensional finite difference time domain simulations.

  6. 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)

    2014-09-15T23:59:59.000Z

    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.

  7. Excitation of Kaluza-Klein gravitational mode

    E-Print Network [OSTI]

    Kunihito Uzawa; Yoshiyuki Morisawa; Shinji Mukohyama

    2000-04-10T23:59:59.000Z

    We investigate excitation of Kaluza-Klein modes due to the parametric resonance caused by oscillation of radius of compactification. We consider a gravitational perturbation around a D-dimensional spacetime, which we compactify on a (D-4)-sphere to obtain a 4-dimensional theory. The perturbation includes the so-called Kaluza-Klein modes, which are massive in 4-dimension, as well as zero modes, which is massless in 4-dimension. These modes appear as scalar, vector and second-rank symmetric tensor fields in the 4-dimensional theory. Since Kaluza-Klein modes are troublesome in cosmology, quanta of these Kaluza-Klein modes should not be excited abundantly. However, if radius of compactification oscillates, then masses of Kaluza-Klein modes also oscillate and, thus, parametric resonance of Kaluza-Klein modes may occur to excite their quanta. In this paper we consider part of Kaluza-Klein modes which correspond to massive scalar fields in 4-dimension and investigate whether quanta of these modes are excited or not in the so called narrow resonance regime of the parametric resonance. We conclude that at least in the narrow resonance regime quanta of these modes are not excited so catastrophically.

  8. Feedback stabilization of resistive shell modes in a reversed field pinch

    SciTech Connect (OSTI)

    Fitzpatrick, R.; Yu, E.P. [Institute for Fusion Studies, Department of Physics, University of Texas at Austin, Austin, Texas 78712-1060 (United States)] [Institute for Fusion Studies, Department of Physics, University of Texas at Austin, Austin, Texas 78712-1060 (United States)

    1999-09-01T23:59:59.000Z

    A reactor relevant reversed field pinch (RFP) must be capable of operating successfully when surrounded by a close-fitting resistive shell whose L/R time is much {ital shorter} than the pulse length. Resonant modes are largely unaffected by the shell resistivity, provided that the plasma rotation is maintained against the breaking effect of nonaxisymmetric eddy currents induced in the shell. This may require an auxiliary momentum source, such as a neutral beam injector. Nonresonant modes are largely unaffected by plasma rotation, and are expected to manifest themselves as nonrotating {ital resistive shell modes} growing on the L/R time of the shell. A general RFP equilibrium is subject to many simultaneously unstable resistive shell modes; the only viable control mechanism for such modes in a RFP reactor is {ital active feedback}. It is demonstrated than an {ital N}-fold toroidally symmetric arrangement of feedback coils, combined with a strictly linear feedback algorithm, is capable of {ital simultaneously stabilizing} all intrinsically unstable resistive shell modes over a wide range of different RFP equilibria. The number of coils in the toroidal direction {ital N}, at any given poloidal angle, must be greater than, or equal to, the range of toroidal mode numbers of the unstable resistive shell modes. However, this range is largely determined by the aspect-ratio of the device. The optimum coil configuration corresponds to one in which each feedback coil slightly overlaps its immediate neighbors in the toroidal direction. The critical current which must be driven around each feedback coils is, at most, a few percent of the equilibrium toroidal plasma current. The feedback scheme is robust to small deviations from pure {ital N}-fold toroidal symmetry or a pure linear response of the feedback circuits. {copyright} {ital 1999 American Institute of Physics.}

  9. Injection locked oscillator system for pulsed metal vapor lasers

    DOE Patents [OSTI]

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

    1988-01-01T23:59:59.000Z

    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.

  10. Laser triggering of water switches in terrawatt-class pulse power accelerators.

    SciTech Connect (OSTI)

    Woodworth, Joseph Ray; Johnson, David Lee (Titan Pulse Sciences, San Leandro, CA); Wilkins, Frank (Bechtel Nevada, Las Vegas, NV); Van De Valde, David (EG& G Technical Services, Albuquerque, NM); Sarkisov, Gennady Sergeevich (Ktech Corporation, Albuquerque, NM); Zameroski, Nathan D.; Starbird, Robert L. (Bechtel Nevada, Las Vegas, NV)

    2005-12-01T23:59:59.000Z

    Focused Beams from high-power lasers have been used to command trigger gas switches in pulse power accelerators for more than two decades. This Laboratory-Directed Research and Development project was aimed at determining whether high power lasers could also command trigger water switches on high-power accelerators. In initial work, we determined that focused light from three harmonics of a small pulsed Nd:YAG laser at 1064 nm, 532 nm, and 355 nm could be used to form breakdown arcs in water, with the lowest breakdown thresholds of 110 J/cm{sup 2} or 14 GW/cm{sup 2} at 532 nm in the green. In laboratory-scale laser triggering experiments with a 170-kV pulse-charged water switch with a 3-mm anode-cathode gap, we demonstrated that {approx}90 mJ of green laser energy could trigger the gap with a 1-{sigma} jitter of less than 2ns, a factor of 10 improvement over the jitter of the switch in its self breaking mode. In the laboratory-scale experiments we developed optical techniques utilizing polarization rotation of a probe laser beam to measure current in switch channels and electric field enhancements near streamer heads. In the final year of the project, we constructed a pulse-power facility to allow us to test laser triggering of water switches from 0.6- MV to 2.0 MV. Triggering experiments on this facility using an axicon lens for focusing the laser and a switch with a 740 kV self-break voltage produced consistent laser triggering with a {+-} 16-ns 1-{sigma} jitter, a significant improvement over the {+-} 24-ns jitter in the self-breaking mode.

  11. Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam

    SciTech Connect (OSTI)

    Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

    2006-05-02T23:59:59.000Z

    This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

  12. 2342 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 39, NO. 12, DECEMBER 2004 A 4-A Quiescent-Current Dual-Mode Digitally

    E-Print Network [OSTI]

    Sanders, Seth

    2342 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 39, NO. 12, DECEMBER 2004 A 4-A Quiescent voltage compatibility between a single-cell lithium-ion battery voltage and a low-voltage integrated with each full charge of the battery, pulse frequency modulation (PFM) mode is preferred for light load

  13. High rate pulse processing algorithms for microcalorimeters

    SciTech Connect (OSTI)

    Rabin, Michael [Los Alamos National Laboratory; Hoover, Andrew S [Los Alamos National Laboratory; Bacrania, Mnesh K [Los Alamos National Laboratory; Tan, Hui [XIA-LLC; Breus, Dimitry [XIA-LLC; Henning, Wolfgang [XIA-LLC; Sabourov, Konstantin [XIA-LLC; Collins, Jeff [XAI-LLC; Warburton, William K [XIA-LLC; Dorise, Bertrand [NIST; Ullom, Joel N [NIST; [NON LANL

    2009-01-01T23:59:59.000Z

    It has been demonstrated that microcalorimeter spectrometers based on superconducting transition-edge-sensor can readily achieve sub-100 eV energy resolution near 100 keV. However, the active volume of a single microcalorimeter has to be small to maintain good energy resolution, and pulse decay times are normally in the order of milliseconds due to slow thermal relaxation. Consequently, spectrometers are typically built with an array of microcalorimeters to increase detection efficiency and count rate. Large arrays, however, require as much pulse processing as possible to be performed at the front end of the readout electronics to avoid transferring large amounts of waveform data to a host computer for processing. In this paper, they present digital filtering algorithms for processing microcalorimeter pulses in real time at high count rates. The goal for these algorithms, which are being implemented in the readout electronics that they are also currently developing, is to achieve sufficiently good energy resolution for most applications while being (a) simple enough to be implemented in the readout electronics and (b) capable of processing overlapping pulses and thus achieving much higher output count rates than the rates that existing algorithms are currently achieving. Details of these algorithms are presented, and their performance was compared to that of the 'optimal filter' that is the dominant pulse processing algorithm in the cryogenic-detector community.

  14. Thyristor stack for pulsed inductive plasma generation

    SciTech Connect (OSTI)

    Teske, C.; Jacoby, J.; Schweizer, W.; Wiechula, J. [Plasmaphysics Group, Institute of Applied Physics, Johann-Wolfgang-Goethe University, 60438 Frankfurt am Main (Germany)

    2009-03-15T23:59:59.000Z

    A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 {mu}s and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/{mu}s.

  15. RF study and simulations of a C-band Barrel Open Cavity (BOC) pulse compressor

    E-Print Network [OSTI]

    Shu, Guan; He, Xiang

    2014-01-01T23:59:59.000Z

    This paper focuses on the RF study of a C-band(5712MHz) BOC pulse compressor. The operating principle of BOC is presented and the technical specifications are determined. The main components of BOC such as the cavity, the matching waveguide, the coupling slots and the tuning rings were numerically simulated by 3-D codes software HFSS and CST Microwave Studio(MWS). The "whispering gallery" mode TM6,1,1 with an unload Q of 100000 was chosen to oscillate in the cavity. An energy multiplication factor of 1.99 and a peak power gain of 6.34 were achieved theoretically.

  16. High-stability time-domain balanced homodyne detector for ultrafast optical pulse applications

    E-Print Network [OSTI]

    Merlin Cooper; Christoph Söller; Brian J. Smith

    2013-03-25T23:59:59.000Z

    Low-noise, efficient, phase-sensitive time-domain optical detection is essential for foundational tests of quantum physics based on optical quantum states and the realization of numerous applications ranging from quantum key distribution to coherent classical telecommunications. Stability, bandwidth, efficiency, and signal-to-noise ratio are crucial performance parameters for effective detector operation. Here we present a high-bandwidth, low-noise, ultra-stable time-domain coherent measurement scheme based on balanced homodyne detection ideally suited to characterization of quantum and classical light fields in well-defined ultrashort optical pulse modes.

  17. 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)

    1993-01-01T23:59:59.000Z

    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.

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

    DOE Patents [OSTI]

    Schultz, F.J.; Caldwell, J.T.

    1993-04-06T23:59:59.000Z

    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.

  19. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    SciTech Connect (OSTI)

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18T23:59:59.000Z

    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.

  20. Seismic pulse propagation with constant Q and stable probability distributions

    E-Print Network [OSTI]

    Francesco Mainardi; Massimo Tomirotti

    2010-08-07T23:59:59.000Z

    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.

  1. Temporally propagated optical pulses, and what they reveal about dispersion handling

    E-Print Network [OSTI]

    Kinsler, Paul

    2015-01-01T23:59:59.000Z

    I derive a temporally propagated uni-directional optical pulse equation valid in the few cycle limit. Temporal propagation is advantageous because it naturally preserves causality, unlike the competing spatially propagated models. The approach generates exact coupled bi-directional equations, which can be efficiently approximated down to a uni-directional form in cases where an optical pulse changes little over one optical cycle. It also also allows a direct term-to-term comparison of an exact bi-directional theory with an approximate uni-directional theory. Notably, temporal propagation handles dispersion in a different way, and this difference serves to highlight existing approximations inherent in spatially propagated treatments of dispersion. Accordingly, I emphasise the need for future work in clarifying the limitations of the dispersion conversion required by these types of approaches; since the only alternative in the few cycle limit may be to resort to the much more computationally intensive full Maxw...

  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.

    used in laser-produced plasma (LPP) for x-ray [20,21] and EUV emission enhancement [22,23]. The DP applications in the fields of microscopy, lithography and x-ray laser. Compared to single-pulse LIBS, DPLIBSRole of laser pre-pulse wavelength and inter-pulse delay on signal enhancement in collinear double

  3. Thermal performance testing of two Thales 9310 pulse-tube cryocoolers for PHyTIR

    SciTech Connect (OSTI)

    Paine, Christopher G. [Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Drive, Pasadena CA 91109 (United States)

    2014-01-29T23:59:59.000Z

    PHyTIR is a NASA-funded technology demonstration for a near-term earth-observing instrument in the thermal infrared spectrum, intended for use in the HyspIRI mission. PHyTIR will use two Thales 9310 single-stage pulse tube cryocoolers, one to directly cool the FPA, the other to simulate a passive radiator. We report performance measurements for the two Thales 9310 cryocoolers intended for inclusion in the PHyTIR demonstrator.

  4. Ultrafast dynamics and fragmentation of C60 in intense laser pulses

    E-Print Network [OSTI]

    Lin, Zheng-Zhe

    2014-01-01T23:59:59.000Z

    The radiation-induced fragmentation of the C60 fullerene was investigated by the tight-binding electron-ion dynamics simulations. In intense laser field, the breathing vibrational mode is much more strongly excited than the pentagonal-pinch mode. The fragmentation effect was found more remarkable at long wavelength lambda>800 nm rather than the resonant wavelengths due to the internal laser-induced dipole force, and the production ratio of C and C2 rapidly grows with increasing wavelength. By such fragmentation law, C atoms, C2 dimers or large Cn fragments could be selectively obtained by changing the laser wavelength. And the fragmentation of C60 by two laser pulses like the multi-step atomic photoionization was investigated.

  5. Multipacting saturation in parallel plate and micro-pulse electron gun

    E-Print Network [OSTI]

    Liao, Lang; Zhao, Minghua

    2014-01-01T23:59:59.000Z

    A novel parallel plate model is proposed that divided the electron cloud into three parts at saturation, and it is studied in detail using both an analytical approach and PIC (Particle In Cell) code simulations. As one part of the electron cloud, ribbons modes are suggested by tracking the trajectory of individual particle, and the aim of this mode form is to simplify the progress of multipacting effect in the parallel plate so as to be eliminated by optimizing RF parameters. The micro-pulse electron gun (MPG) has demonstrated the potential to address the need for high peak and average current electron beams, hence studying the multipacting in MPG is essential. On the basis of multipacting studying in the parallel plate, it is clear that increasing the cavity voltage is of interest in yielding high quality beams in the gun.

  6. A Self-Biasing Pulsed Depressed Collector

    SciTech Connect (OSTI)

    Kemp, Mark A.; Jensen, Aaron; Neilson, Jeff; /SLAC

    2014-05-29T23:59:59.000Z

    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)

  7. ARE PULSING SOLITARY WAVES RUNNING INSIDE THE SUN?

    SciTech Connect (OSTI)

    Wolff, Charles L., E-mail: charles.l.wolff@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-09-10T23:59:59.000Z

    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.

  8. Estimating the pressure of laser-induced plasma shockwave by stimulated Raman shift of lattice translational modes

    SciTech Connect (OSTI)

    Li Zhanlong [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Shan Xiaoning; Li Zuowei; Zhou Mi; Men Zhiwei [College of Physics, Jilin University, Changchun 130012 (China); Cao Junsheng [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Wang Yiding [College of Electronic Science and Engineering and Key Laboratory on Integrated Optoelectronics, Jilin University, Changchun 130012 (China); Sun Chenglin [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)

    2012-07-09T23:59:59.000Z

    The current paper investigates stimulated Raman scattering (SRS) when laser-induced plasma is formed in heavy water by focusing an intense pulsed 532 nm Nd:YAG laser beam at room temperature. An unexpected low-frequency SRS line attributed to the lattice translational modes of ice-VII (D{sub 2}O) is observed. The pressure of the plasma shockwave is estimated using low-frequency SRS line shift.

  9. Single mode terahertz quantum cascade amplifier

    E-Print Network [OSTI]

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

    2014-10-06T23:59:59.000Z

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

  10. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect (OSTI)

    NONE

    1998-03-01T23:59:59.000Z

    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.

  11. Dispersion compensation for attosecond electron pulses

    SciTech Connect (OSTI)

    Hansen, Peter; Baumgarten, Cory; Batelaan, Herman; Centurion, Martin [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2012-08-20T23:59:59.000Z

    We propose a device to compensate for the dispersion of attosecond electron pulses. The device uses only static electric and magnetic fields and therefore does not require synchronization to the pulsed electron source. Analogous to the well-known optical dispersion compensator, an electron dispersion compensator separates paths by energy in space. Magnetic fields are used as the dispersing element, while a Wien filter is used for compensation of the electron arrival times. We analyze a device with a size of centimeters, which can be applied to ultrafast electron diffraction and microscopy, and fundamental studies.

  12. 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)

    2012-05-08T23:59:59.000Z

    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.

  13. 2012 Long Term NTSA

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011 Mon, 11/28/2011 -April2012-Long-Term-NTSA Sign In

  14. Long Term by Group

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocsCenterCentera A B C D ELong Term Care |

  15. Terms and Conditions | EMSL

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus TomAboutManusScience and How ToMayTen-Year Site PlansTerms and

  16. 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

    2014-01-01T23:59:59.000Z

    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...

  17. 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, E-mail: zhaoliang0526@163.com; Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)

    2014-06-15T23:59:59.000Z

    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.

  18. Numerical simulation of operation modes in atmospheric pressure uniform barrier discharge excited by a saw-tooth voltage

    SciTech Connect (OSTI)

    Li Xuechen; Niu Dongying; Yin Zengqian [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Fang Tongzhen; Wang Long [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-08-15T23:59:59.000Z

    The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ion appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.

  19. Phase Modulator Programming to Get Flat Pulses with Desired Length and Power from the CTF3 Pulse Compressors

    E-Print Network [OSTI]

    Shaker, Seyd Hamed; Skowronski, Piotr; Syratchev, Igor; Tecker, Frank

    2010-01-01T23:59:59.000Z

    The pulse compressor is located after the klystron to increase the power peak by storing the energy at the beginning and releasing it near the end of klystron output pulse. In the CTF3 pulse compressors a doubling of the peak power is achieved according to our needs and the machine parameters. The magnitude of peak power, pulse length and flatness can be controlled by using a phase modulator for the input signal of klystrons. A C++ code is written to simulate the pulse compressor behaviour according to the klystron output pulse power. By manually changing the related parameters in the code for the best match, the quality factor and the filling time of pulse compressor cavities can be determined. This code also calculates and sends the suitable phase to the phase modulator according to the klystron output pulse power and the desired pulse length and peak power

  20. 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)

    2013-05-10T23:59:59.000Z

    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.

  1. Long-term multipactor discharge in multicarrier systems

    SciTech Connect (OSTI)

    Anza, S.; Vicente, C.; Gimeno, B.; Boria, V. E.; Armendariz, J. [Aurora Software and Testing S.L., Parque Cientifico Universitat de Valencia, Poligono 'La Coma' s/n, 46980 Paterna (Spain); Departamento de Comunicaciones, Universidad Politecnica de Valencia Camino de Vera s/n, 46022 Valencia (Spain); Departamento de Fisica Aplicada y Electromagnetismo - ICMUV, Universitat de Valencia c/ Dr. Moliner, 50, 46100 Valencia (Spain); Departamento de Comunicaciones, Universidad Politecnica de Valencia Camino de Vera s/n, 46022 Valencia (Spain); Aurora Software and Testing S.L., Parque Cientifico Universitat de Valencia, Poligono 'La Coma' s/n, 46980 Paterna (Spain)

    2007-08-15T23:59:59.000Z

    A new mechanism of long-term multipactor in multicarrier systems is studied employing both analytical and numerical methods. In particular, the investigation is focused on the impact that a realistic secondary emission yield at low energies produces on the development of long term multipactor. A novel analytical model for this interperiod charge accumulation is presented using the traditional multipactor theory for parallel plates, and approximating the multicarrier signal as a single-carrier signal modulated by a pulsed signal envelope. The analytical predictions are verified by numerical simulations for a typical rectangular waveguide. The analytical and numerical results demonstrate that the susceptibility of the system to develop a long-term multipactor discharge increases with higher values of low-energy secondary emission yield.

  2. Long-Term Risk From Actinides in the Environment: Modes of Mobility

    SciTech Connect (OSTI)

    Shawki Ibrahim, Ph.D.

    2001-05-24T23:59:59.000Z

    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.

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

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines AboutDecember 2005 (Thousand9,0,Information Administration390 2.387NASEO 2006/07Summer8

  4. Evanescent-wave coupled right angled buried waveguide: Applications in carbon nanotube mode-locking

    SciTech Connect (OSTI)

    Mary, R.; Thomson, R. R.; Kar, A. K., E-mail: a.k.kar@hw.ac.uk [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Brown, G. [Optoscribe Ltd, 0/14 Alba Innovation Centre, Alba Campus, Livingston EH54 7GA (United Kingdom)] [Optoscribe Ltd, 0/14 Alba Innovation Centre, Alba Campus, Livingston EH54 7GA (United Kingdom); Beecher, S. J. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom)] [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Popa, D.; Sun, Z.; Torrisi, F.; Hasan, T.; Milana, S.; Bonaccorso, F.; Ferrari, A. C. [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom)] [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2013-11-25T23:59:59.000Z

    We present an evanescent-field device based on a right-angled waveguide. This consists of orthogonal waveguides, with their points of intersection lying along an angled facet of the chip. Light guided along one waveguide is incident at the angled dielectric-air facet at an angle exceeding the critical angle, so that the totally internally reflected light is coupled into the second waveguide. By depositing a nanotube film on the angled surface, the chip is then used to mode-lock an Erbium doped fiber ring laser with a repetition rate of 26?MHz, and pulse duration of 800?fs.

  5. Mode-locked Lasers Applied to Deflecting a Near Earth Object on Collision Course with Earth

    E-Print Network [OSTI]

    Fork, Richard; Burgess, Luke; Bergstue, Grant

    2013-01-01T23:59:59.000Z

    We consider synchronized trains of sub-picosecond pulses generated by mode-locked lasers applied to deflection of near Earth objects (NEO) on collision course with Earth. Our method is designed to avoid a predicted collision of the NEO with Earth by at least the diameter of Earth. We estimate deflecting a 10,000 MT NEO, such as the asteroid which struck Earth near Chelyabinsk, Russia to be feasible within several months using average power in the ten kilowatt range. We see this deflection method as scalable to larger NEO to a degree not possible using continuous laser systems.

  6. Optimization of pulsed-DEER measurements for Gd-based labels...

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

    Optimization of pulsed-DEER measurements for Gd-based labels: choice of operational frequencies, pulse durations and positions, Optimization of pulsed-DEER measurements for...

  7. E-Print Network 3.0 - atmospheric pressure pulsed Sample Search...

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

    see the needle jump with the pulse 1. Record the pressure measured... by the sphygmomanometer between pulses. 2. Record the amount the pressure changes during a pulse. 3....

  8. Pressure wave charged repetitively pulsed gas laser

    DOE Patents [OSTI]

    Kulkarny, Vijay A. (Redondo Beach, CA)

    1982-01-01T23:59:59.000Z

    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.

  9. Pulse thermal energy transport/storage system

    DOE Patents [OSTI]

    Weislogel, Mark M. (23133 Switzer Rd., Brookpark, OH 44142)

    1992-07-07T23:59:59.000Z

    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.

  10. Mode Shape Estimation Algorithms Under Ambient Conditions: A Comparative Review

    SciTech Connect (OSTI)

    Dosiek, Luke; Zhou, Ning; Pierre, John W.; Huang, Zhenyu; Trudnowski, Daniel J.

    2013-05-01T23:59:59.000Z

    Abstract—This paper provides a comparative review of five existing ambient electromechanical mode shape estimation algorithms, i.e., the Transfer Function (TF), Spectral, Frequency Domain Decomposition (FDD), Channel Matching, and Subspace Methods. It is also shown that the TF Method is a general approach to estimating mode shape and that the Spectral, FDD, and Channel Matching Methods are actually special cases of it. Additionally, some of the variations of the Subspace Method are reviewed and the Numerical algorithm for Subspace State Space System IDentification (N4SID) is implemented. The five algorithms are then compared using data simulated from a 17-machine model of the Western Electricity Coordinating Council (WECC) under ambient conditions with both low and high damping, as well as during the case where ambient data is disrupted by an oscillatory ringdown. The performance of the algorithms is compared using the statistics from Monte Carlo Simulations and results from measured WECC data, and a discussion of the practical issues surrounding their implementation, including cases where power system probing is an option, is provided. The paper concludes with some recommendations as to the appropriate use of the various techniques. Index Terms—Electromechanical mode shape, small-signal stability, phasor measurement units (PMU), system identification, N4SID, subspace.

  11. Bures distance as a measure of entanglement for two-mode squeezed thermal states

    SciTech Connect (OSTI)

    Marian, Paulina [Institute for Theoretical Atomic, Molecular and Optical Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Department of Chemistry, University of Bucharest, Boulevard Regina Elisabeta 4-12, R-030018 Bucharest (Romania); Marian, Tudor A. [Institute for Theoretical Atomic, Molecular and Optical Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Bucharest, P.O. Box MG-11, R-077125 Bucharest-Magurele (Romania); Scutaru, Horia [Center for Advanced Studies in Physics of the Romanian Academy, Calea 13 Septembrie 13, R-050711 Bucharest (Romania)

    2003-12-01T23:59:59.000Z

    We propose a reliable entanglement measure for a two-mode squeezed thermal state of the quantum electromagnetic field in terms of its Bures distance to the set of all separable states of the same kind. The requisite fidelity of a pair of two-mode squeezed thermal states is exactly evaluated. By applying the Peres-Simon criterion of separability, we find the closest separable state. This enables us to establish an insightful expression of the amount of entanglement. We also derive the relative entropy of a two-mode squeezed thermal state with respect to another one. This quantity is exploited in the pure-state case by undertaking a similar approximation for the entropic entanglement of a two-mode squeezed vacuum state. Comparison with previous work lends support to our approach that replaces the reference set of all separable Gaussian states by its subset consisting only of the squeezed thermal ones.

  12. Reliability Failure Mode, Effects, and Criticality Analysis

    E-Print Network [OSTI]

    Rathbun, Julie A.

    Reliability Failure Mode, Effects, and Criticality Analysis Addendum 1; HFE ~ ATM501 PAGE I I. Hiebert Reliability Engineer HFE · B-1 f #12;~~.~-~ -_ ~ ~ Reliability Failure Mode, Effects were slight adjustment in the linearizing resistors. The reliability is effected upward by the deletion

  13. Normalizable fermion modes in a holographic superconductor

    E-Print Network [OSTI]

    Steven S. Gubser; Fabio D. Rocha; Pedro Talavera

    2009-11-18T23:59:59.000Z

    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.

  14. Broadband frequency mode entanglement in waveguided PDC

    E-Print Network [OSTI]

    Eckstein, Andreas

    2008-01-01T23:59:59.000Z

    We report the observation of beatings of the coincidence event rate in a Hong-Ou-Mandel interference (HOMI) between signal and idler photons from a parametric downconversion process inside a multi-mode KTP waveguide. As explanation we introduce bi-photonic states entangled in their broadband frequency modes and propose a suitable entanglement witness.

  15. 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

  16. Cost-Effective Multi-Mode Offloading with peer-assisted communications

    E-Print Network [OSTI]

    Gorinsky, Sergey

    cost in terms of financial settlement, energy consump- tion, and user satisfaction. Our simulationsCost-Effective Multi-Mode Offloading with peer-assisted communications Ioannis Komnios a, , Fani caused by the ongoing explosive growth in mobile data traffic. In this paper, we propose Cost

  17. Series-counterpulse repetitive-pulse inductive storage circuit

    DOE Patents [OSTI]

    Honig, E.M.

    1984-06-05T23:59:59.000Z

    A high-power series-counterpulse repetitive-pulse inductive energy storage and transfer circuit includes an opening switch, a main energy storage coil, and a counterpulse capacitor. The local pulse is initiated simultaneously with the initiation of the counterpulse used to turn the opening switch off. There is no delay from command to output pulse. During the load pulse, the counterpulse capacitor is automatically charged with sufficient energy to accomplish the load counterpulse which terminates the load pulse and turns the load switch off. When the main opening switch is reclosed to terminate the load pulse, the counterpulse capacitor discharges through the load, causing a rapid, sharp cutoff of the load pulse as well as recovering any energy remaining in the load inductance. The counterpulse capacitor is recharged to its original condition by the main energy storage coil after the load pulse is over, not before it begins.

  18. IBEX - a pulsed power accelerator that generates no prepulse

    SciTech Connect (OSTI)

    Ramirez, J.J.; Corley, J.P.; Mazarakis, M.G.

    1983-01-01T23:59:59.000Z

    Intense relativistic electron beams are produced in vacuum diodes driven by pulsed power accelerators. For pulse widths approx. 100 nsec, pulse forming lines (PPL) are used to generate the accelerating voltage pulse. This pulse is produced by sequential switching of stored energy through two or more stages. Capacitance and/or inductive coupling usually results in the generation of a low level prepulse voltage some time during the switching sequence. This prepulse is known to have a substantial effect on the performance of the vacuum diode during the main accelerating pulse. Most accelerators use various schemes for reducing this prepulse to acceptable levels. The Isolated Blumlein PPL concept was developed at Sandia to allow for the generation of the main accelerating pulse without generating a prepulse voltage. This concept was implemented into the IBEX accelerator that generates a 4 MV, 100 kA, 20 nsec output pulse. Design and performance data are presented.

  19. Controlling electron injection in laser plasma accelerators using multiple pulses

    SciTech Connect (OSTI)

    Matlis, N. H.; Geddes, C. G. R.; Plateau, G. R.; Esarey, E.; Schroeder, C.; Bruhwiler, D.; Cormier-Michel, E.; Chen, M.; Yu, L.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Tech-X Corporation, 5621 Arapahoe Ave, Suite A, Boulder CO 80303 (United States); Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 (China); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States) and University of California, Berkeley, CA 94720 (United States)

    2012-12-21T23:59:59.000Z

    Use of counter-propagating pulses to control electron injection in laser-plasma accelerators promises to be an important ingredient in the development of stable devices. We discuss the colliding pulse scheme and associated diagnostics.

  20. 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

    2011-11-01T23:59:59.000Z

    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.

  1. Nonclassicality in two-mode BEC

    E-Print Network [OSTI]

    Sandip Kumar Giri; Biswajit Sen; C H Raymond Ooi; Anirban Pathak

    2013-07-05T23:59:59.000Z

    An analytic operator solution of a generalized quantum mechanical Hamiltonian of two-mode Bose Einstein condensates (BECs) is obtained and the same is used to investigate the nonclassical properties of the modes present in the system. Nonclassical characters are observed by means of single mode and intermodal squeezing, single mode and intermodal sub-Poissonian boson statistics and intermodal entanglement. In addition to the traditionally studied lower order nonclassical properties, signatures of higher order nonclassical characters of two-mode BEC systems are also obtained by investigating the possibility of higher order antibunching and higher order entanglement. The mutual relation among the observed nonclassicalities and their evolution (variation) with rescaled time and the ratio of the single boson tunneling amplitude ($\\varepsilon$) and the coupling constant for the intra-modal interaction ($\\kappa$) are also reported.

  2. Time-domain squeezing and quantum distributions in the pulsed regime

    SciTech Connect (OSTI)

    Adamyan, N. H. [Yerevan State University, 1 A Manoogian, 375049 Yerevan (Armenia); Adamyan, H. H. [Institute for Physical Research, National Academy of Sciences, Ashtarak-2, 378410 (Armenia); Kryuchkyan, G. Yu. [Yerevan State University, 1 A Manoogian, 375049 Yerevan (Armenia); Institute for Physical Research, National Academy of Sciences, Ashtarak-2, 378410 (Armenia)

    2008-02-15T23:59:59.000Z

    We investigate time-dependent properties of Einstein-Podolsky-Rosen (EPR) light beams generated in a nondegenerate optical parametric oscillator (NOPO) driven by a sequence of laser pulses with Gaussian time-dependent envelopes. This investigation continues our previous analysis [H. H. Adamyan and G. Yu. Kryuchkyan, Phys. Rev. A 74, 023810 (2006)] and involves problems of two-mode quadrature squeezing as well as intensity-difference squeezing in the time domain. The peculiarities of EPR beams are also discussed in the framework of phase-space quantum distributions. Two kinds of non-Gaussian Wigner functions, for the reduced one-mode state of periodically pulsed NOPO and for EPR beams which are combined on a one-half beam splitter are calculated numerically. We also investigate the Wigner functions of intensity-correlated twin beams following the conditional photon state-preparation scheme. It is demonstrated that the Wigner functions involve negative values in parts of the phase space for the schemes with one, two, and three photons.

  3. Photon statistics of atomic fluorescence after {pi}-pulse excitation

    SciTech Connect (OSTI)

    Yoshimi, Kazuyoshi [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); Koshino, Kazuki [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

    2010-09-15T23:59:59.000Z

    The photon statistics of atomic fluorescence after {pi}-pulse excitation is investigated in a system in which the input and output ports are connected to an atom. Since spontaneous decay during input pulse excitation occurs, the output pulse generally contains a multiphoton component with a certain probability. We quantitatively evaluate the probability of the output pulse containing multiple photons and determine the conditions for ideal single-photon generation.

  4. 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

    2005-12-13T23:59:59.000Z

    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.

  5. Gravitational-wave modes from precessing black-hole binaries

    E-Print Network [OSTI]

    Michael Boyle; Lawrence E. Kidder; Serguei Ossokine; Harald P. Pfeiffer

    2014-09-22T23:59:59.000Z

    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.

  6. Transportable automated ammonia sensor based on a pulsed thermoelectrically cooled

    E-Print Network [OSTI]

    Transportable automated ammonia sensor based on a pulsed thermoelectrically cooled quantum single-frequency, thermoelectrically cooled, pulsed quantum-cascade laser with an embedded distributed absorption spectroscopy with a pulsed QC DFB laser was reported in Ref. 3, where wavelength modulation

  7. Information processing with longitudinal spectral decomposition of ultrafast pulses

    E-Print Network [OSTI]

    Fainman, Yeshaiahu

    Information processing with longitudinal spectral decomposition of ultrafast pulses Robert E of waveforms depending on whether their frequency response is or is not known a priori. Ultrafast pulses prove synthesis and detection relying on longitudinal spectral decomposition of subpicosecond optical pulses

  8. Origins of Pulsing Regime in Cocurrent Packed-Bed Flows

    E-Print Network [OSTI]

    McCready, Mark J.

    , 6, and 8 mm using an air-water flow. By measuring the flow distance until pulses are observedOrigins of Pulsing Regime in Cocurrent Packed-Bed Flows B.A. Wilhite+ , B. Blackwell+ , J. Kacmar of the formation for cocurrent downflow pulse flow was studied experimentally in a packed-bed of inert spheres of 3

  9. Sample Residential Program Term Sheet

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

    Goal DRAFT U.S. DOE Sample Residential Program Term Sheet - DRAFT Introduction is seeking to develop an energy...

  10. E-Print Network 3.0 - angle rf pulses Sample Search Results

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

    pulse operating on M: RFx pulse operating on FZ: RF pulses K-Space Scheffler 1999: PDF... " cos() 2 sin2 ( 2) 1st 1st RF pulse 12;E. Wong, BE278, UCSD Winter 2011...

  11. Long-term testing

    SciTech Connect (OSTI)

    Ferber, M.; Graves, G.A. Jr.

    1994-12-31T23:59:59.000Z

    Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000--10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

  12. Edge modes in band topological insulators

    E-Print Network [OSTI]

    Lukasz Fidkowski; T. S. Jackson; Israel Klich

    2011-05-09T23:59:59.000Z

    We characterize gapless edge modes in translation invariant topological insulators. We show that the edge mode spectrum is a continuous deformation of the spectrum of a certain gluing function defining the occupied state bundle over the Brillouin zone (BZ). Topologically non-trivial gluing functions, corresponding to non-trivial bundles, then yield edge modes exhibiting spectral flow. We illustrate our results for the case of chiral edge states in two dimensional Chern insulators, as well as helical edges in quantum spin Hall states.

  13. Mixed Mode Fuel Injector And Injection System

    DOE Patents [OSTI]

    Stewart, Chris Lee (Normal, IL); Tian, Ye (Bloomington, IL); Wang, Lifeng (Normal, IL); Shafer, Scott F. (Morton, IL)

    2005-12-27T23:59:59.000Z

    A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set that are controlled respectively by first and second three way needle control valves. Each fuel injector includes first and second concentric needle valve members. One of the needle valve members moves to an open position for a homogenous charge injection event, while the other needle valve member moves to an open position for a conventional injection event. The fuel injector has the ability to operate in a homogenous charge mode with a homogenous charge spray pattern, a conventional mode with a conventional spray pattern or a mixed mode.

  14. Source depth for solar p-modes

    E-Print Network [OSTI]

    Pawan Kumar; Sarbani Basu

    2000-06-15T23:59:59.000Z

    Theoretically calculated power spectra are compares with observed solar p-mode velocity power spectra over a range of mode degree and frequency. The depth for the sources responsible for exciting p-modes of frequency 2.0 mHz is determined from the asymmetry of their power spectra and found to be about 800 km below the photosphere for quadrupole sources and 150 km if sources are dipole. The source depth for high frequency oscillations of frequency greater than about 6 mHz is 180 (50) km for quadrupole (dipole) sources.

  15. Combining attosecond XUV pulses with coincidence spectroscopy

    SciTech Connect (OSTI)

    Sabbar, M., E-mail: msabbar@phys.ethz.ch; Heuser, S.; Boge, R.; Lucchini, M.; Cirelli, C.; Keller, U. [Department of Physics, ETH Zurich, 8093 Zurich (Switzerland); Gallmann, L. [Department of Physics, ETH Zurich, 8093 Zurich (Switzerland); Institute of Applied Physics, University of Bern, 3012 Bern (Switzerland)

    2014-10-15T23:59:59.000Z

    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.

  16. 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

    2005-01-01T23:59:59.000Z

    susceptibility is given by #4;#1;#1;#5;p#2; #12; ? #6;#7;#8;p #5; #5;2 . #1;7#2; Therefore, at a position z, the delayed probe pulse is given by p#1;t,z#2; = p0 exp ? #1;t ? z/vg#2;22T2 , #1;8#2; where the group velocity of the optical pulse is vg#12... Security Agency, and the Army Research Office. #3;1#4; T. Kamiya, F. Saito, O. Wada, and H. Yajima, Femtosecond Technology #1;Springer, Berlin, 1999#2;. #3;2#4; S. E. Harris and L. V. Hau, Phys. Rev. Lett. 82, 4611 #1;1999#2;; P. C. Ku, C. J. Chang...

  17. 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.

    2013-04-02T23:59:59.000Z

    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.

  18. Pulsed atmospheric fluidized bed combustor apparatus

    DOE Patents [OSTI]

    Mansour, Momtaz N. (Columbia, MD)

    1993-10-26T23:59:59.000Z

    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.

  19. Laser cooling with ultrafast pulse trains

    E-Print Network [OSTI]

    David Kielpinski

    2003-06-14T23:59:59.000Z

    We propose a new laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires vacuum-ultraviolet laser light, while multielectron atoms need laser light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and carbon appears feasible, and extension of the technique to molecules may be possible.

  20. Kinetic theory of geodesic acoustic and related modes

    E-Print Network [OSTI]

    Kinetic theory of geodesic acoustic and related modes A.I. Smolyakov Department of Physics · Geodesic Acoustic Modes (GAM) are relatively high frequency eigen-modes supported by plasma compressibility history of GAM and related modes ·1968 : Geodesic acoustic modes: Winsor, Johnson, Dawson ·2000-05: Surge

  1. Field Quantization, Photons and Non-Hermitean Modes

    E-Print Network [OSTI]

    S. A. Brown; B. J. Dalton

    2001-09-10T23:59:59.000Z

    Field quantization in three dimensional unstable optical systems is treated by expanding the vector potential in terms of non-Hermitean (Fox-Li) modes in both the cavity and external regions. The cavity non-Hermitean modes (NHM) are treated using the paraxial and monochromaticity approximations. The NHM bi-orthogonality relationships are used in a standard canonical quantization procedure based on introducing generalised coordinates and momenta for the electromagnetic (EM) field. The quantum EM field is equivalent to a set of quantum harmonic oscillators (QHO), associated with either the cavity or the external region NHM. This confirms the validity of the photon model in unstable optical systems, though the annihilation and creation operators for each QHO are not Hermitean adjoints. The quantum Hamiltonian for the EM field is the sum of non-commuting cavity and external region contributions, each of which is sum of independent QHO Hamiltonians for each NHM, but the external field Hamiltonian also includes a coupling term responsible for external NHM photon exchange processes. Cavity energy gain and loss processes is associated with the non-commutativity of cavity and external region operators, given in terms of surface integrals involving cavity and external region NHM functions on the cavity-external region boundary. The spontaneous decay of a two-level atom inside an unstable cavity is treated using the essential states approach and the rotating wave approximation. Atomic transitions leading to cavity NHM photon absorption have a different coupling constant to those leading to photon emission, a feature resulting from the use of NHM functions. Under certain conditions the decay rate is enhanced by the Petermann factor.

  2. Pulsed Power Peer Review Committee Report

    SciTech Connect (OSTI)

    BLOOMQUIST,DOUGLAS D.

    2000-12-01T23:59:59.000Z

    In 1993, the Government Performance and Results Act (GPRA, PL 103-62) was enacted. GPRA, which applies to all federal programs, has three components: strategic plans, annual performance plans, and metrics to show how well annual plans are being followed. As part of meeting the GRPA requirement in FY2000, a 14-member external peer review panel (the Garwin Committee) was convened on May 17-19, 2000 to review Sandia National Laboratories' Pulsed Power Programs as a component of the Performance Appraisal Process negotiated with the Department of Energy (DOE). The scope of the review included activities in inertial confinement fission (ICF), weapon physics, development of radiation sources for weapons effects simulation, x-ray radiography, basic research in high energy density physics (HEDP), and pulsed power technology research and development. In his charge to the committee, Jeffrey Quintenz, Director of Pulsed Power Sciences (1600) asked that the review be based on four criteria (1) quality of science, technology, and engineering, (2) programmatic performance, management, and planning, (3) relevance to national needs and agency missions, and (4) performance in the operation and construction of major research facilities. In addition, specific programmatic questions were posed by the director and by the DOE-Defense Programs (DP). The accompanying report, produced as a SAND document, is the report of the committee's findings.

  3. Pulsed-electron-beam melting of Fe

    SciTech Connect (OSTI)

    Knapp, J.A.; Follstaedt, D.M.

    1981-01-01T23:59:59.000Z

    Pulsed (50 nsec) electron beams with deposited energies of 1.1 to 2.3 J/cm/sup 2/ have been used to rapidly melt a surface layer of Fe. Calculations show that this range of energies produces melt depths from 0.4 to 1.2 ..mu..m and melt times of 100 to 500 nsec. Optical microscopy and SEM of pulse treated polycrystalline foils show slip traces, as well as a general smoothing of surface features which shows that melting has occurred. TEM shows that the resolidified material is bcc, and that the material within a grain is epitaxial with the substrate. TEM also shows slip traces along (110) planes, as well as a high density of dislocations, both extended and loop. At the highest energy, subgrain boundaries are observed. Some samples were implanted with 1 x 10/sup 16/ Sn/cm/sup 2/ at 150 keV. After pulse treatment, the Sn depth profile was observed to have broadened, consistent with liquid phase diffusion. The Sn had the unexpected effect of suppressing slip at the sample surface.

  4. Oscillating plasma bubbles. II. Pulsed experiments

    SciTech Connect (OSTI)

    Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2012-08-15T23:59:59.000Z

    Time-dependent phenomena have been investigated in plasma bubbles which are created by inserting spherical grids into an ambient plasma and letting electrons and ions form a plasma of different parameters than the ambient one. There are no plasma sources inside the bubble. The grid bias controls the particle flux. There are sheaths on both sides of the grid, each of which passes particle flows in both directions. The inner sheath or plasma potential develops self consistently to establish charge neutrality and divergence free charge and mass flows. When the electron supply is restricted, the inner sheath exhibits oscillations near the ion plasma frequency. When all electrons are excluded, a virtual anode forms on the inside sheath, reflects all ions such that the bubble is empty. By pulsing the ambient plasma, the lifetime of the bubble plasma has been measured. In an afterglow, plasma electrons are trapped inside the bubble and the bubble decays as slow as the ambient plasma. Pulsing the grid voltage yields the time scale for filling and emptying the bubble. Probes have been shown to modify the plasma potential. Using pulsed probes, transient ringing on the time scale of ion transit times through the bubble has been observed. The start of sheath oscillations has been investigated. The instability mechanism has been qualitatively explained. The dependence of the oscillation frequency on electrons in the sheath has been clarified.

  5. A method to synchronize signals from multiple patient monitoring devices through a single input channel for inclusion in list-mode acquisitions

    SciTech Connect (OSTI)

    O’Connor, J. Michael; Pretorius, P. Hendrik; Johnson, Karen; King, Michael A., E-mail: Michael.King@umassmed.edu [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: This technical note documents a method that the authors developed for combining a signal to synchronize a patient-monitoring device with a second physiological signal for inclusion into list-mode acquisition. Our specific application requires synchronizing an external patient motion-tracking system with a medical imaging system by multiplexing the tracking input with the ECG input. The authors believe that their methodology can be adapted for use in a variety of medical imaging modalities including single photon emission computed tomography (SPECT) and positron emission tomography (PET). Methods: The authors insert a unique pulse sequence into a single physiological input channel. This sequence is then recorded in the list-mode acquisition along with the R-wave pulse used for ECG gating. The specific form of our pulse sequence allows for recognition of the time point being synchronized even when portions of the pulse sequence are lost due to collisions with R-wave pulses. This was achieved by altering our software used in binning the list-mode data to recognize even a portion of our pulse sequence. Limitations on heart rates at which our pulse sequence could be reliably detected were investigated by simulating the mixing of the two signals as a function of heart rate and time point during the cardiac cycle at which our pulse sequence is mixed with the cardiac signal. Results: The authors have successfully achieved accurate temporal synchronization of our motion-tracking system with acquisition of SPECT projections used in 17 recent clinical research cases. In our simulation analysis the authors determined that synchronization to enable compensation for body and respiratory motion could be achieved for heart rates up to 125 beats-per-minute (bpm). Conclusions: Synchronization of list-mode acquisition with external patient monitoring devices such as those employed in motion-tracking can reliably be achieved using a simple method that can be implemented using minimal external hardware and software modification through a single input channel, while still recording cardiac gating signals.

  6. Improvement of the Temporal Contrast of High-Power Laser Pulses

    E-Print Network [OSTI]

    high gain8 pass amplifier ultrafast pulse cleaner 107 preamplifierJ ultrafast pulse cleaner ASE for pulse amplification. In our laser system, we insert the preamplifier and ultrafast pulse cleaner before for optimizing the performance of the ultrafast pulse cleaner. After passing through the pulse cleaner, the high

  7. PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation

    E-Print Network [OSTI]

    Subramaniam, Anandh

    PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation The Uniaxial Tension Test Mechanisms underlying Plastic Deformation Strengthening mechanisms Mechanical Metallurgy George E Dieter McClick here to know about all the mechanisms by which materials fail #12;Slip (Dislocation motion) Plastic

  8. Whispering-gallery-mode-based seismometer

    SciTech Connect (OSTI)

    Fourguette, Dominique Claire; Otugen, M Volkan; Larocque, Liane Marie; Ritter, Greg Aan; Meeusen, Jason Jeffrey; Ioppolo, Tindaro

    2014-06-03T23:59:59.000Z

    A whispering-gallery-mode-based seismometer provides for receiving laser light into an optical fiber, operatively coupling the laser light from the optical fiber into a whispering-gallery-mode-based optical resonator, operatively coupling a spring of a spring-mass assembly to a housing structure; and locating the whispering-gallery-mode-based optical resonator between the spring-mass assembly and the housing structure so as to provide for compressing the whispering-gallery-mode-based optical resonator between the spring-mass assembly and the housing structure responsive to a dynamic compression force from the spring-mass assembly responsive to a motion of the housing structure relative to an inertial frame of reference.

  9. Rotary Mode Core Sample System availability improvement

    SciTech Connect (OSTI)

    Jenkins, W.W.; Bennett, K.L.; Potter, J.D. [Westinghouse Hanford Co., Richland, WA (United States); Cross, B.T.; Burkes, J.M.; Rogers, A.C. [Southwest Research Institute (United States)

    1995-02-28T23:59:59.000Z

    The Rotary Mode Core Sample System (RMCSS) is used to obtain stratified samples of the waste deposits in single-shell and double-shell waste tanks at the Hanford Site. The samples are used to characterize the waste in support of ongoing and future waste remediation efforts. Four sampling trucks have been developed to obtain these samples. Truck I was the first in operation and is currently being used to obtain samples where the push mode is appropriate (i.e., no rotation of drill). Truck 2 is similar to truck 1, except for added safety features, and is in operation to obtain samples using either a push mode or rotary drill mode. Trucks 3 and 4 are now being fabricated to be essentially identical to truck 2.

  10. Two-Mode Theory of BEC Interferometry

    E-Print Network [OSTI]

    B J Dalton

    2007-02-03T23:59:59.000Z

    A theory of BEC interferometry in an unsymmetrical double-well trap has been developed for small boson numbers, based on the two-mode approximation. The bosons are initially in the lowest mode of a single well trap, which is split into a double well and then recombined. Possible fragmentations into separate BEC states in each well during the splitting/recombination process are allowed for. The BEC is treated as a giant spin system, the fragmented states are eigenstates of S^2 and Sz. Self-consistent sets of equations for the amplitudes of the fragmented states and for the two single boson mode functions are obtained. The latter are coupled Gross-Pitaevskii equations. Interferometric effects may be measured via boson numbers in the first excited mode

  11. Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion

    SciTech Connect (OSTI)

    Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

    2013-04-22T23:59:59.000Z

    We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

  12. Transient X-ray pulsar V0332+53: pulse phase-resolved spectroscopy and the reflection model

    E-Print Network [OSTI]

    Lutovinov, A A; Suleimanov, V F; Mushtukov, A A; Doroshenko, V; Nagirner, D I; Poutanen, J

    2015-01-01T23:59:59.000Z

    We present the results of the pulse phase- and luminosity-resolved spectroscopy of the transient X-ray pulsar V0332+53, performed for the first time in a wide luminosity range (1-40)x10^{37} erg/s during a giant outburst observed by the RXTE observatory in Dec 2004 - Feb 2005. We characterize the spectra quantitatively and built the detailed "three-dimensional" picture of spectral variations with pulse phase and throughout the outburst. We show that all spectral parameters are strongly variable with the pulse phase, and the pattern of this variability significantly changes with luminosity directly reflecting the associated changes in the structure of emission regions and their beam patterns. Obtained results are qualitatively discussed in terms of the recently developed reflection model for the formation of cyclotron lines in the spectra of X-ray pulsars.

  13. Analysis of microwave leaky modes propagating through laser plasma filaments column waveguide

    SciTech Connect (OSTI)

    Alshershby, Mostafa; Hao Zuoqiang; Lin Jingquan [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)

    2012-12-15T23:59:59.000Z

    A plasma column waveguide formed by a bundle of closely spaced plasma filaments induced by the propagation of ultrafast laser pulses in air and revived by a longer infrared laser pulse is shown to support microwave radiation. We consider values of both the plasma electron density and microwave frequency for which the refractive index of plasma is lower than the refractive index of air; therefore, a leaky plasma waveguide can be realized in extremely high frequency band. The guiding mechanism does not require high conductance of the plasma and can be easily excited by using commercial femtosecond laser sources. A theoretical study of leaky mode characteristics of isotropic and homogeneous plasma column waveguides is investigated with several values of plasma and waveguide structure parameters. The microwave transmission loss was found to be mainly caused by the microwave leakage through the air-plasma interface and is weakly dependent on the plasma absorption. In spite of losses of microwaves caused by leakage and plasma absorption, it is shown to be much lower than both that accompanying to surface waves attaching to single conducting plasma wire and the free space propagation over distances in the order of the filament length, which opens exciting perspectives for short distance point to point wireless transmission of pulsed-modulated microwaves.

  14. Dirac Quasinormal modes of MSW black holes

    E-Print Network [OSTI]

    Sebastian, Saneesh

    2014-01-01T23:59:59.000Z

    In this paper we study the Dirac quasinormal modes of an uncharged 2 + 1 black hole proposed by Mandal et. al and referred to as MSW black hole in this work. The quasi- normal mode is studied using WKB approximation method. The study shows that the imaginary part of quasinormal frequencies increases indicating that the oscillations are damping and hence the black hole is stable against Dirac perturbations.

  15. Dirac Quasinormal modes of MSW black holes

    E-Print Network [OSTI]

    Saneesh Sebastian; V. C. Kuriakose

    2014-01-15T23:59:59.000Z

    In this paper we study the Dirac quasinormal modes of an uncharged 2 + 1 black hole proposed by Mandal et. al and referred to as MSW black hole in this work. The quasi- normal mode is studied using WKB approximation method. The study shows that the imaginary part of quasinormal frequencies increases indicating that the oscillations are damping and hence the black hole is stable against Dirac perturbations.

  16. Propagation Plane waves -High order Modes

    E-Print Network [OSTI]

    Berlin,Technische Universität

    1 Propagation · Plane waves - High order Modes y x a One wave: p(x,y,t)=p0 cos(k y)e-jk x e j t vy(y,t)= 0 ; y=0,a xy } ky = n a Propagation · Plane waves - High order Modes x n a p(x,y,t)=pn cos( y + - +- + + - +- + - + + +- - - (m,n) #12;4 Propagation · Circular duct ­ Helical waves (spiralling waves) kc=m/a kz k

  17. Propagation Plane waves -High order Modes

    E-Print Network [OSTI]

    Berlin,Technische Universität

    1 Propagation · Plane waves - High order Modes y x a ky = n a One wave: p(x,y,t)=p0 cos(k y)e-jk x e j t vy(y,t)= 0 ; y=0,a xy } Propagation · Plane waves - High order Modes x n a p(x,y,t)=pn cos( y;4 Propagation · Circular duct ­ Helical waves (spiralling waves) kc=m/a kz kH Projection: Propagation #12

  18. Forecasting Turbulent Modes with Nonparametric Diffusion Models

    E-Print Network [OSTI]

    Tyrus Berry; John Harlim

    2015-01-27T23:59:59.000Z

    This paper presents a nonparametric diffusion modeling approach for forecasting partially observed noisy turbulent modes. The proposed forecast model uses a basis of smooth functions (constructed with the diffusion maps algorithm) to represent probability densities, so that the forecast model becomes a linear map in this basis. We estimate this linear map by exploiting a previously established rigorous connection between the discrete time shift map and the semi-group solution associated to the backward Kolmogorov equation. In order to smooth the noisy data, we apply diffusion maps to a delay embedding of the noisy data, which also helps to account for the interactions between the observed and unobserved modes. We show that this delay embedding biases the geometry of the data in a way which extracts the most predictable component of the dynamics. The resulting model approximates the semigroup solutions of the generator of the underlying dynamics in the limit of large data and in the observation noise limit. We will show numerical examples on a wide-range of well-studied turbulent modes, including the Fourier modes of the energy conserving Truncated Burgers-Hopf (TBH) model, the Lorenz-96 model in weakly chaotic to fully turbulent regimes, and the barotropic modes of a quasi-geostrophic model with baroclinic instabilities. In these examples, forecasting skills of the nonparametric diffusion model are compared to a wide-range of stochastic parametric modeling approaches, which account for the nonlinear interactions between the observed and unobserved modes with white and colored noises.

  19. Edge-localized-modes in tokamaks

    SciTech Connect (OSTI)

    Leonard, A. W. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States)

    2014-09-15T23:59:59.000Z

    Edge-localized-modes (ELMs) are a ubiquitous feature of H-mode in tokamaks. When gradients in the H-mode transport barrier grow to exceed the MHD stability limit the ELM instability grows explosively, rapidly transporting energy and particles onto open field lines and material surfaces. Though ELMs provide additional particle and impurity transport through the H-mode transport barrier, enabling steady operation, the resulting heat flux transients to plasma facing surfaces project to large amplitude in future low collisionality burning plasma tokamaks. Measurements of the ELM heat flux deposition onto material surfaces in the divertor and main chamber indicate significant broadening compared to inter-ELM heat flux, with a timescale for energy deposition that is consistent with sonic ion flow and numerical simulation. Comprehensive ELM simulation is highlighting the important physics processes of ELM transport including parallel transport due to magnetic reconnection and turbulence resulting from collapse of the H-mode transport barrier. Encouraging prospects for ELM control and/or suppression in future tokamaks include intrinsic modes of ELM free operation, ELM triggering with frequent small pellet injection and the application of 3D magnetic fields.

  20. Noise-like pulse based on dissipative four-wave-mixing with photonic crystal fiber filled by reduced graphene oxide

    E-Print Network [OSTI]

    Gao, Lei; Huang, Wei

    2014-01-01T23:59:59.000Z

    A noise-like pulse based on dissipative four-wave-mixing in a fiber cavity with photonic crystal fiber filled by reduced graphene oxide is proposed. Due to large evanescent field provided by 3 cm photonic crystal fiber and ultrahigh nonlinearity of reduced graphene oxide, this mixed structure provides excellent saturable absorption and high nonlinearity, which are necessary for generating four-wave-mixing (FWM). We experimentally prove that the mode-locked laser transfers its energy from center wavelength to sidebands through degenerate FWM, and new frequencies are generated via cascaded FWM among those sidebands. During this process, the frequencies located in various orders of longitudinal modes of the ring cavity are supported, and others are suppressed due to destructive interference. As the longitudinal modes of the cavity with a spacing of 6.874 MHz are partially supported, the loosely fixed phase relationship results in noise-like pulse with a coherent peak of 530 fs locating on a pedestal of 730.693 p...

  1. Sandia National Laboratories: Failure Mode and Effect Analysis...

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

    ProcessFailure Mode and Effect Analysis (FMEA) Tutorial Failure Mode and Effect Analysis (FMEA) Tutorial Failure Mode and Effect Analysis (FMEA) Tutorial (SAND2012-0602W) Tagged...

  2. Compressed Wannier modes found from an $L_1$ regularized energy functional

    E-Print Network [OSTI]

    Farzin Barekat; Ke Yin; Russel E. Caflisch; Stanley J. Osher; Rongjie Lai; Vidvuds Ozolins

    2014-03-26T23:59:59.000Z

    We propose a method for calculating Wannier functions of periodic solids directly from a modified variational principle for the energy, subject to the requirement that the Wannier functions are orthogonal to all their translations ("shift-orthogonality"). Localization is achieved by adding an $L_1$ regularization term to the energy functional. This approach results in "compressed" Wannier modes with compact support, where one parameter $\\mu$ controls the trade-off between the accuracy of the total energy and the size of the support of the Wannier modes. Efficient algorithms for shift-orthogonalization and solution of the variational minimization problem are demonstrated.

  3. Two-photon interference with continuous-wave multi-mode coherent light

    E-Print Network [OSTI]

    Yong-Su Kim; Oliver Slattery; Paulina S. Kuo; Xiao Tang

    2013-09-12T23:59:59.000Z

    We report two-photon interference with continuous-wave multi-mode coherent light. We show that the two-photon interference, in terms of the detection time difference, reveals two-photon beating fringes with the visibility $V = 0.5$. While scanning the optical delay of the interferometer, Hong-Ou-Mandel dips or peaks are measured depending on the chosen detection time difference. The HOM dips/peaks are repeated when the optical delay and the first-order coherence revival period of the multi-mode coherent light are the same.

  4. Electrostatic mode associated with the pinch velocity in reversed field pinch simulations

    SciTech Connect (OSTI)

    Delzanno, Gian Luca [Los Alamos National Laboratory (LANL); Chacon, Luis [Oak Ridge National Laboratory (ORNL); Finn, John M. [Los Alamos National Laboratory (LANL)

    2008-01-01T23:59:59.000Z

    The existence of a new phenomenon in reversed field pinch (RFP) simulations related to the equilibrium pinch flow is discussed. This behavior is due to the inward equilibrium flow, but is strongly affected by boundary conditions on the perturbed azimuthal flow. It is important to understand and control this mechanism in single helicity simulations of RFPs. This mechanism can be explained in terms of an electrostatic instability related to a mode which can occur in fluid dynamics. In a simple linear model, it is shown that the mode, which is related to the inward advection of angular momentum from the edge, can be stabilized by using homogeneous Dirichlet (no-slip) boundary conditions at the wall. Behavior due to this mode is present in nonlinear simulations with zero-viscous-stress boundary conditions on the tangential velocity at the wall and, even in the presence of the usual magnetohydrodynamic modes, this mode can dominate the nonlinear dynamics of the velocity. In nonlinear simulations with Dirichlet boundary conditions on the tangential velocity, behavior associated with this electrostatic mode is not observed.

  5. Electrostatic mode associated with the pinch velocity in reversed field pinch simulations

    SciTech Connect (OSTI)

    Delzanno, Gian Luca; Finn, John M. [T-15 Plasma Theory Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Chacon, Luis [T-15 Plasma Theory Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

    2008-12-15T23:59:59.000Z

    The existence of a new phenomenon in reversed field pinch (RFP) simulations related to the equilibrium pinch flow is discussed. This behavior is due to the inward equilibrium flow, but is strongly affected by boundary conditions on the perturbed azimuthal flow. It is important to understand and control this mechanism in single helicity simulations of RFPs. This mechanism can be explained in terms of an electrostatic instability related to a mode which can occur in fluid dynamics. In a simple linear model, it is shown that the mode, which is related to the inward advection of angular momentum from the edge, can be stabilized by using homogeneous Dirichlet (no-slip) boundary conditions at the wall. Behavior due to this mode is present in nonlinear simulations with zero-viscous-stress boundary conditions on the tangential velocity at the wall and, even in the presence of the usual magnetohydrodynamic modes, this mode can dominate the nonlinear dynamics of the velocity. In nonlinear simulations with Dirichlet boundary conditions on the tangential velocity, behavior associated with this electrostatic mode is not observed.

  6. Effects of carbon nanotubes and graphene oxide absorbers on the noise of mode-locked fiber lasers

    E-Print Network [OSTI]

    Li, Xiaohui; Yu, Xuechao; Wang, Yonggang; Wang, Yishan; Meng, Bo; Tang, Yulong; Yu, Xia; Zhang, Ying; Sun, Zhipei; Shum, Perry Ping; Wang, Qi Jie

    2014-01-01T23:59:59.000Z

    Phase noise is very important for the ultrafast pulse application in telecommunication, ultrafast diagnose, material science, and biology. In this paper, two types of carbon nano-materials, single-wall carbon nanotube and graphene oxide, are investigated for noise suppression in ultrafast photonics. Various properties of the wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the phase noise of the ultrafast pulses. A reduced-noise femtosecond fiber laser is experimentally demonstrated by optimizing the above parameters of carbon material based SAs. The phase noise reduction more than 10 dB at 10 kHz can be obtained in the experiments. To our knowledge, this is the first time that the relationship between different carbon material based SAs and the phase noise of mode-locked lasers has been investigated. This work will pave the way to get a high-quality ultrashort pulse in passively mode-locked fiber lasers.

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

    SciTech Connect (OSTI)

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

    2014-02-24T23:59:59.000Z

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

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

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

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

  9. Unregulated Emissions from High-Efficiency Clean Combustion Modes...

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

    Unregulated Emissions from High-Efficiency Clean Combustion Modes - ORNL-FEERC Unregulated Emissions from High-Efficiency Clean Combustion Modes - ORNL-FEERC Poster presentation at...

  10. Modeling Combustion Control for High Power Diesel Mode Switching

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

    and Emissions Research Conference 2010 Modeling Combustion Control for High Power Diesel Mode Switching P-20 Motivation * High power LTC-diesel mode operation * Transient...

  11. Burning Modes and Oxidation Rates of Soot: Relevance to Diesel...

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

    Burning Modes and Oxidation Rates of Soot: Relevance to Diesel Particulate Traps Burning Modes and Oxidation Rates of Soot: Relevance to Diesel Particulate Traps Presentation given...

  12. Sequestering Uranium from Seawater: Binding Strength and Modes...

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

    Sequestering Uranium from Seawater: Binding Strength and Modes of Uranyl Complexes with Glutarimidedioxime Sequestering Uranium from Seawater: Binding Strength and Modes of Uranyl...

  13. Mixed-mode diesel HCCI with External Mixture Formation: Preliminary...

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

    Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results 2003 DEER Conference...

  14. D-3 FALL TERM TERM CR. COURSE DEPARTMENT

    E-Print Network [OSTI]

    Cui, Yan

    Community Oral Health Dr. P.N. Gregory 2 PDCH 302 Pediatric Dental Clinic* Pediatric Dentistry Dr. H.K. Sharp 1 PDCH 304 Patient Centered Dentistry Pediatric Dentistry Ms. M. Seeberg 2 PERI 301 Basic *Continues through Spring Term D-3 SPRING TERM 1 DSOM 305 Advanced Dental Radiology Oral Maxillofacial

  15. D-3 FALL TERM TERM CR COURSE DEPARTMENT

    E-Print Network [OSTI]

    Cui, Yan

    Community Oral Health Dr. P.N. Gregory 2 PDCH 302 Pediatric Dental Clinic* Pediatric Dentistry Dr. H.K. Sharp 1 PDCH 304 Patient Centered Dentistry Pediatric Dentistry Ms. M. Seeberg 2 PERI 301 Basic *Continues through Spring Term D-3 SPRING TERM 1 DSOM 305 Advanced Dental Radiology Oral Maxillofacial

  16. Tunable sub-20 fs pulses from a 500 kHz OPCPA with 15 W average power based on an all-ytterbium laser

    E-Print Network [OSTI]

    Puppin, Michele; Prochnow, Oliver; Ahrens, Jan; Binhammer, Thomas; Morgner, Uwe; Krenz, Marcel; Wolf, Martin; Ernstorfer, Ralph

    2014-01-01T23:59:59.000Z

    An optical parametric chirped pulse amplifier fully based on Yb lasers at 500 kHz is described. Passive optical-synchronization is achieved between a fiber laser-pumped white-light and a 515 nm pump produced with a 200 W picosecond Yb:YAG InnoSlab amplifier. An output power up to 19.7 W with long-term stability of 0.3% is demonstrated for wavelength tunable pulses between 680 nm and 900 nm and spectral stability of 0.2%; 16.5 W can be achieved with a bandwidth supporting 5.4 fs pulses. We demonstrate compression of 30 microjoule pulses to sub-20 fs duration with a prism compressor, suitable for high harmonic generation.

  17. Inductive gas line for pulsed lasers

    DOE Patents [OSTI]

    Benett, William J. (Livermore, CA); Alger, Terry W. (Tracy, CA)

    1985-01-01T23:59:59.000Z

    A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

  18. Inductive gas line for pulsed lasers

    DOE Patents [OSTI]

    Benett, W.J.; Alger, T.W.

    1982-09-29T23:59:59.000Z

    A gas laser having a metal inlet gas feed line assembly shaped as a coil, to function as an electrical inductance and therefore high impedance to pulses of electric current applied to electrodes at opposite ends of a discharge tube of a laser, for example. This eliminates a discharge path for the laser through the inlet gas feed line. A ferrite core extends through the coil to increase the inductance of the coil and provide better electric isolation. By elimination of any discharge breakdown through the gas supply, efficiency is increased and a significantly longer operating lifetime of the laser is provided.

  19. Chamber dynamic research with pulsed power

    SciTech Connect (OSTI)

    PETERSON,ROBERT R.; OLSON,CRAIG L.; RENK,TIMOTHY J.; ROCHAU,GARY E.; SWEENEY,MARY ANN

    2000-05-15T23:59:59.000Z

    In Inertial Fusion Energy (IFE), Target Chamber Dynamics (TCD) is an integral part of the target chamber design and performance. TCD includes target output deposition of target x-rays, ions and neutrons in target chamber gases and structures, vaporization and melting of target chamber materials, radiation-hydrodynamics in target chamber vapors and gases, and chamber conditions at the time of target and beam injections. Pulsed power provides a unique environment for IFE-TCD validation experiments in two important ways: they do not require the very clean conditions which lasers need and they currently provide large x-ray and ion energies.

  20. Optical penetration sensor for pulsed laser welding

    DOE Patents [OSTI]

    Essien, Marcelino (Albuquerque, NM); Keicher, David M. (Albuquerque, NM); Schlienger, M. Eric (Albuquerque, NM); Jellison, James L. (Albuquerque, NM)

    2000-01-01T23:59:59.000Z

    An apparatus and method for determining the penetration of the weld pool created from pulsed laser welding and more particularly to an apparatus and method of utilizing an optical technique to monitor the weld vaporization plume velocity to determine the depth of penetration. A light source directs a beam through a vaporization plume above a weld pool, wherein the plume changes the intensity of the beam, allowing determination of the velocity of the plume. From the velocity of the plume, the depth of the weld is determined.

  1. Pulsed Power Technology at Sandia National Laboratories

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassive Solar HomePromising Science for1 2011 Publications Wood, V., Panzer, PULSED

  2. The Homopolar Pulse Billet Heating Process

    E-Print Network [OSTI]

    Keith, R. E.; Weldon, W. F.

    1982-01-01T23:59:59.000Z

    Research Institute Rept. No. IEEE Int'l. Pulsed Power Conf., 1st, NP-1285, Dec. 1979. Lubbock, TX, Nov. 9-11, 1976. 12. Driga, M. D., Nasa, S. A., Rylande~, 2. Weldon, W. F., Driga, M. D., Woodson, H. G., Weldon, W. F., and Woodson, H. H. H...., and Ryl ander, H.' G., "The H., "Fundamental Limitations 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...

  3. 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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs &JeffIntensitySurface Los Alamos09Pulse 2012

  4. 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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs &JeffIntensitySurface Los Alamos09Pulse

  5. Spatiotemporal reconstruction of list-mode PET data

    SciTech Connect (OSTI)

    Nichols, Thomas E.; Qi, Jinyi; Asma, Evren; Leahy, Richard M.

    2002-03-01T23:59:59.000Z

    We describe a method for computing a continuous time estimate of tracer density using list-mode positron emission tomography data. The rate function in each voxel is modeled as an inhomogeneous Poisson process whose rate function can be represented using a cubic B-spline basis. The rate functions are estimated by maximizing the likelihood of the arrival times of detected photon pairs over the control vertices of the spline, modified by quadratic spatial and temporal smoothness penalties and a penalty term to enforce nonnegativity. Randoms rate functions are estimated by assuming independence between the spatial and temporal randoms distributions. Similarly, scatter rate functions are estimated by assuming spatiotemporal independence and that the temporal distribution of the scatter is proportional to the temporal distribution of the trues. A quantitative evaluation was performed using simulated data and the method is also demonstrated in a human study using 11C-raclopride.

  6. Method of estimating pulse response using an impedance spectrum

    DOE Patents [OSTI]

    Morrison, John L; Morrison, William H; Christophersen, Jon P; Motloch, Chester G

    2014-10-21T23:59:59.000Z

    Electrochemical Impedance Spectrum data are used to predict pulse performance of an energy storage device. The impedance spectrum may be obtained in-situ. A simulation waveform includes a pulse wave with a period greater than or equal to the lowest frequency used in the impedance measurement. Fourier series coefficients of the pulse train can be obtained. The number of harmonic constituents in the Fourier series are selected so as to appropriately resolve the response, but the maximum frequency should be less than or equal to the highest frequency used in the impedance measurement. Using a current pulse as an example, the Fourier coefficients of the pulse are multiplied by the impedance spectrum at corresponding frequencies to obtain Fourier coefficients of the voltage response to the desired pulse. The Fourier coefficients of the response are then summed and reassembled to obtain the overall time domain estimate of the voltage using the Fourier series analysis.

  7. Single molecule imaging with longer x-ray laser pulses

    E-Print Network [OSTI]

    Martin, Andrew V; Caleman, Carl; Quiney, Harry M

    2015-01-01T23:59:59.000Z

    In serial femtosecond crystallography, x-ray laser pulses do not need to outrun all radiation damage processes because Bragg diffraction exceeds the damage-induced background scattering for longer pulses ($\\sim$ 50--100 fs). This is due to a "self-gating pulse" effect whereby damage terminates Bragg diffraction prior to the pulse completing its passage through the sample, as if that diffraction were produced by a shorter pulse of equal fluence. We show here that a similar gating effect applies to single molecule diffraction with respect to spatially uncorrelated damage processes like ionization and ion diffusion. The effect is clearly seen in calculations of the diffraction contrast, by calculating the diffraction of average structure separately to the diffraction from statistical fluctuations of the structure due to damage ("damage noise"). Our results suggest that sub-nanometer single molecule imaging with longer pulses, like those produced at currently operating facilities, should not yet be ruled out. The...

  8. Long-term environmental stewardship.

    SciTech Connect (OSTI)

    Nagy, Michael David

    2010-08-01T23:59:59.000Z

    The purpose of this Supplemental Information Source Document is to effectively describe Long-Term Environmental Stewardship (LTES) at Sandia National Laboratories/New Mexico (SNL/NM). More specifically, this document describes the LTES and Long-Term Stewardship (LTS) Programs, distinguishes between the LTES and LTS Programs, and summarizes the current status of the Environmental Restoration (ER) Project.

  9. Microcalorimeter Spectroscopy at High Pulse Rates: a Multi-Pulse Fitting Technique

    E-Print Network [OSTI]

    Fowler, J W; Doriese, W B; Fischer, D A; Jaye, C; Joe, Y I; O'Neil, G C; Swetz, D S; Ullom, J N

    2015-01-01T23:59:59.000Z

    Transition edge sensor microcalorimeters can measure x-ray and gamma-ray energies with very high energy resolution and high photon-collection efficiency. For this technology to reach its full potential in future x-ray observatories, each sensor must be able to measure hundreds or even thousands of photon energies per second. Current "optimal filtering" approaches to achieve the best possible energy resolution work only for photons well isolated in time, a requirement in direct conflict with the need for high-rate measurements. We describe a new analysis procedure to allow fitting for the pulse height of all photons even in the presence of heavy pulse pile-up. In the limit of isolated pulses, the technique reduces to the standard optimal filtering with long records. We employ reasonable approximations to the noise covariance function in order to render multi-pulse fitting computationally viable even for very long data records. The technique is employed to analyze x-ray emission spectra at 600 eV and 6 keV at r...

  10. Benchmarking kinetic calculations of resistive wall mode stability

    SciTech Connect (OSTI)

    Berkery, J. W.; Sabbagh, S. A. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Liu, Y. Q. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Wang, Z. R.; Logan, N. C.; Park, J.-K.; Manickam, J. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Betti, R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2014-05-15T23:59:59.000Z

    Validating the calculations of kinetic resistive wall mode (RWM) stability is important for confidently predicting RWM stable operating regions in ITER and other high performance tokamaks for disruption avoidance. Benchmarking the calculations of the Magnetohydrodynamic Resistive Spectrum—Kinetic (MARS-K) [Y. Liu et al., Phys. Plasmas 15, 112503 (2008)], Modification to Ideal Stability by Kinetic effects (MISK) [B. Hu et al., Phys. Plasmas 12, 057301 (2005)], and Perturbed Equilibrium Nonambipolar Transport (PENT) [N. Logan et al., Phys. Plasmas 20, 122507 (2013)] codes for two Solov'ev analytical equilibria and a projected ITER equilibrium has demonstrated good agreement between the codes. The important particle frequencies, the frequency resonance energy integral in which they are used, the marginally stable eigenfunctions, perturbed Lagrangians, and fluid growth rates are all generally consistent between the codes. The most important kinetic effect at low rotation is the resonance between the mode rotation and the trapped thermal particle's precession drift, and MARS-K, MISK, and PENT show good agreement in this term. The different ways the rational surface contribution was treated historically in the codes is identified as a source of disagreement in the bounce and transit resonance terms at higher plasma rotation. Calculations from all of the codes support the present understanding that RWM stability can be increased by kinetic effects at low rotation through precession drift resonance and at high rotation by bounce and transit resonances, while intermediate rotation can remain susceptible to instability. The applicability of benchmarked kinetic stability calculations to experimental results is demonstrated by the prediction of MISK calculations of near marginal growth rates for experimental marginal stability points from the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)].

  11. High-power efficient cw and pulsed lasers based on bulk Yb : KYW crystals with end diode pumping

    SciTech Connect (OSTI)

    Kim, G H; Yang, G H; Lee, D S; Kulik, Alexander V; Sall', E G; Chizhov, S A; Yashin, V E; Kang, U

    2012-04-30T23:59:59.000Z

    End-diode-pumped lasers based on one and two Yb : KYW crystals operating in cw and Q-switched regimes, as well as in the regime of mode-locking, are studied. The single-crystal laser generated stable ultrashort (shorter than 100 fs) laser pulses at wavelengths of 1035 and 1043 nm with an average power exceeding 1 W. The average output power of the two-crystal laser exceeded 18 W in the cw regime and 16 W in the Q-switched regime with a slope efficiency exceeding 30%.

  12. Ultraslow dissociation of the H{sub 2}{sup +} molecular ion via two-color ultrafast laser pulses

    SciTech Connect (OSTI)

    Moser, B.; Gibson, G. N. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2009-10-15T23:59:59.000Z

    We report a mode of dissociative ionization in an intense two-color laser field. When bond softened by the superposition of 800 and 400 nm ultrafast laser pulses in a narrow intensity range, H{sub 2}{sup +} molecular ions experience ultraslow dissociation. This near-zero kinetic-energy release is supported by theoretical simulations and two-color field-dressed adiabatic potential curves. Furthermore, we show that the shift to lower energy of a known bond-softened peak can be explained by the influence of a two-color field-induced potential well. Such ultraslow dissociation can facilitate ultrafast time-resolved spectroscopy of molecules.

  13. A compact streak camera for 150 fs time resolved measurement of bright pulses in ultrafast electron diffraction

    SciTech Connect (OSTI)

    Kassier, G. H.; Haupt, K.; Erasmus, N.; Rohwer, E. G.; Bergmann, H. M. von; Schwoerer, H. [Laser Research Institute, University of Stellenbosch, Private Bag X1, 7602 Matieland (South Africa); Coelho, S. M. M.; Auret, F. D. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa)

    2010-10-15T23:59:59.000Z

    We have developed a compact streak camera suitable for measuring the duration of highly charged subrelativistic femtosecond electron bunches with an energy bandwidth in the order of 0.1%, as frequently used in ultrafast electron diffraction (UED) experiments for the investigation of ultrafast structural dynamics. The device operates in accumulation mode with 50 fs shot-to-shot timing jitter, and at a 30 keV electron energy, the full width at half maximum temporal resolution is 150 fs. Measured durations of pulses from our UED gun agree well with the predictions from the detailed charged particle trajectory simulations.

  14. Device For Trapping Laser Pulses In An Optical Delay Line

    DOE Patents [OSTI]

    Yu, David U. L. (Rancho Palos Verdes, CA); Bullock, Donald L. (Los Angeles, CA)

    1997-12-23T23:59:59.000Z

    A device for maintaining a high-energy laser pulse within a recirculating optical delay line for a period time to optimize the interaction of the pulse with an electron beam pulse train comprising closely spaced electron micropulses. The delay line allows a single optical pulse to interact with many of the electron micropulses in a single electron beam macropulse in sequence and for the introduction of additional optical pulses to interact with the micropulses of additional electron beam macropulses. The device comprises a polarization-sensitive beam splitter for admitting an optical pulse to and ejecting it from the delay line according to its polarization state, a Pockels cell to control the polarization of the pulse within the delay line for the purpose of maintaining it within the delay line or ejecting it from the delay line, a pair of focusing mirrors positioned so that a collimated incoming optical pulse is focused by one of them to a focal point where the pulse interacts with the electron beam and then afterwards the pulse is recollimated by the second focusing mirror, and a timing device which synchronizes the introduction of the laser pulse into the optical delay line with the arrival of the electron macropulse at the delay line to ensure the interaction of the laser pulse with a prescribed number of electron micropulses in sequence. In a first embodiment of the invention, the principal optical elements are mounted with their axes collinear. In a second embodiment, all principal optical elements are mounted in the configuration of a ring.

  15. Pulse Transformer Design for Magnet Powering in Particle Accelerators

    E-Print Network [OSTI]

    Aguglia, D

    2014-01-01T23:59:59.000Z

    This paper presents an optimal design procedure for pulse transformers fed by power converters for supplying pulsed current magnets in particle accelerators. Usually their volume must be minimized because of limited space available in the accelerator tunnel. Analytical and numerical models are presented as well as an experimental validation and a real case study where the design tool is exploited to derive a wide variety of solutions depending on the pulse transformers location with respect to the magnet position.

  16. Detecting individual gravity modes in the Sun

    E-Print Network [OSTI]

    Garcia, R A; Eff-Darwich, A; Garrido, R; Jimenez, A; Mathis, S; Moya, A; Palle, P L; Regulo, C; Salabert, D; Suarez, J C; Turck-Chieze, S

    2009-01-01T23:59:59.000Z

    Many questions are still open regarding the structure and the dynamics of the solar core. By constraining more this region in the solar evolution models, we can reduce the incertitudes on some physical processes and on momentum transport mechanisms. A first big step was made with the detection of the signature of the dipole-gravity modes in the Sun, giving a hint of a faster rotation rate inside the core. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as dipole gravity modes. In that case, those modes can be characterized, thus bringing better constraints on the rotation of the core as well as some structural parameters such as the density at these very deep layers of the Sun interior.

  17. A new metric of the low-mode asymmetry for ignition target designs

    SciTech Connect (OSTI)

    Gu, Jianfa, E-mail: gu-jianfa@iapcm.ac.cn; Dai, Zhensheng; Fan, Zhengfeng; Zou, Shiyang, E-mail: zou-shiyang@iapcm.ac.cn; Ye, Wenhua; Pei, Wenbing; Zhu, Shaoping [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)] [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2014-01-15T23:59:59.000Z

    In the deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility, the measured neutron yield and hot spot pressure are significantly lower than simulations. Understanding the underlying physics of the deficit is essential to achieving ignition. This paper investigates the low-mode areal density asymmetry in the main fuel of ignition capsule. It is shown that the areal density asymmetry breaks up the compressed shell and significantly reduces the conversion of implosion kinetic energy to hot spot internal energy, leading to the calculated hot spot pressure and neutron yield quite close to the experimental data. This indicates that the low-mode shell areal density asymmetry can explain part of the large discrepancy between simulations and experiments. Since only using the hot spot shape term could not adequately characterize the effects of the shell areal density asymmetry on implosion performance, a new metric of the low-mode asymmetry is developed to accurately measure the probability of ignition.

  18. Pulsed combustion process for black liquor gasification

    SciTech Connect (OSTI)

    Durai-Swamy, K.; Mansour, M.N.; Warren, D.W.

    1991-02-01T23:59:59.000Z

    The objective of this project is to test an energy efficient, innovative black liquor recovery system on an industrial scale. In the MTCI recovery process, black liquor is sprayed directly onto a bed of sodium carbonate solids which is fluidized by steam. Direct contact of the black liquor with hot bed solids promotes high rates of heating and pyrolysis. Residual carbon, which forms as a deposit on the particle surface, is then gasified by reaction with steam. Heat is supplied from pulse combustor resonance tubes which are immersed within the fluid bed. A portion of the gasifier product gas is returned to the pulse combustors to provide the energy requirements of the reactor. Oxidized sulfur species are partially reduced by reaction with the gasifier products, principally carbon monoxide and hydrogen. The reduced sulfur decomposed to solid sodium carbonate and gaseous hydrogen sulfide (H{sub 2}S). Sodium values are recovered by discharging a dry sodium carbonate product from the gasifier. MTCI's indirectly heated gasification technology for black liquor recovery also relies on the scrubbing of H{sub 2}S for product gases to regenerate green liquor for reuse in the mill circuit. Due to concerns relative to the efficiency of sulfur recovery in the MTCI integrated process, an experimental investigation was undertaken to establish performance and design data for this portion of the system.

  19. Pulse spectral evolution of GRBs: implication as standard candle

    E-Print Network [OSTI]

    Basak, Rupal

    2012-01-01T23:59:59.000Z

    Using an \\emph{empirical} description of a prompt GRB pulse, we analyze the individual pulses of all Fermi/GBM GRBs with known redshifts, till July 2009. This description is simultaneous in time and energy and allows one to determine the peak energy of Band spectrum at zero fluence ($E_{peak,0}$). We demonstrate, for the first time, that the $E_{peak,0}$ bears a very strong correlation with the isotropic energy of the individual pulses, and hence, each pulse can be used as a luminosity indicator. As a physical description is needed in order to use GRB pulses for cosmological purposes, we explore other physical spectral models. As pulses are the building blocks of a GRB, we choose another sample of Fermi/GBM GRBs having bright, long and single/ separable pulse(s) and fit the time-resolved spectra of the individual pulses with the Band model and a model consisting of a blackbody and a power-law. Both these models give acceptable fits. We find that the peak energy/ temperature always decreases exponentially with...

  20. Suppression of Magnetic State Decoherence Using Ultrafast Optical Pulses

    E-Print Network [OSTI]

    C. Search; P. R. Berman

    2000-03-01T23:59:59.000Z

    It is shown that the magnetic state decoherence produced by collisions in a thermal vapor can be suppressed by the application of a train of ultrafast optical pulses.

  1. A modified parallel HVDC convertor for 24 pulse operation

    SciTech Connect (OSTI)

    Arrillaga, J.; Villablanca, M. (Canterbury Univ., Christchurch (New Zealand))

    1991-01-01T23:59:59.000Z

    A new concept of convertor design is proposed suitable for large current ratings, such as used in back-to-back HVDC interconnections. It consists of a parallel 12-pulse configuration involving two phase shifted bridges and a thyristor-tapped interphase reactor. The dc. ripple present across the interphase reactor is used to derive a current waveform which, when added to the original phase currents, effectively doubles the converters pulse number. It is shown theoretically and experimentally that the use of dc.-ripple reinjection achieves 24-pulse operations from a conventional 12-pulse HVDC converter configuration.

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

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

    100 femtoseconds, synchronization to another ultrafast source ranging from infrared to x-ray wavelengths, and the ability to shape the time envelope of the pulse. Among the...

  3. Spatial and spectral effects in subcritical system pulsed experiments

    SciTech Connect (OSTI)

    Dulla, S.; Nervo, M.; Ravetto, P. [Politecnico di Torino, Dipartimento Energia, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy); Carta, M. [ENEA - C.R. CASACCIA, UTFISSM-PRONOC, Via Anguillarese, 301, 00123 S. Maria di Galeria (Italy)

    2013-07-01T23:59:59.000Z

    Accurate neutronic models are needed for the interpretation of pulsed experiments in subcritical systems. In this work, the extent of spatial and spectral effects in the pulse propagation phenomena is investigated and the analysis is applied to the GUINEVERE experiment. The multigroup cross section data is generated by the Monte Carlo SERPENT code and the neutronic evolution following the source pulse is simulated by a kinetic diffusion code. The results presented show that important spatial and spectral aspects need to be properly accounted for and that a detailed energy approach may be needed to adequately capture the physical features of the system to the pulse injection. (authors)

  4. Saturable inductor and transformer structures for magnetic pulse compression

    DOE Patents [OSTI]

    Birx, Daniel L. (Londonderry, NH); Reginato, Louis L. (Orinda, CA)

    1990-01-01T23:59:59.000Z

    Saturable inductor and transformer for magnetic compression of an electronic pulse, using a continuous electrical conductor looped several times around a tightly packed core of saturable inductor material.

  5. Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler

    DOE Patents [OSTI]

    Shekarriz, Alireza (Kennewick, WA); Sheen, David M. (Richland, WA)

    2000-01-01T23:59:59.000Z

    According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.

  6. Self-Similar Modes of Coherent Diffusion

    E-Print Network [OSTI]

    O. Firstenberg; P. London; D. Yankelev; R. Pugatch; M. Shuker; N. Davidson

    2010-08-16T23:59:59.000Z

    Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical diffraction. In an experiment of light storage in a gas of diffusing atoms, a complex initial condition is imprinted, and its diffusion dynamics is monitored. The self-similarity of both the amplitude and the phase pattern is demonstrated, and an algebraic decay associated with the mode order is measured. Notably, as opposed to a regular diffusion spreading, a self-similar contraction of a special subset of the solutions is predicted and observed.

  7. Head-Tail Modes for Strong Space Charge

    SciTech Connect (OSTI)

    Burov, Alexey

    2008-12-01T23:59:59.000Z

    Head-tail modes are described here for the space charge tune shift significantly exceeding the synchrotron tune. General equation for the modes is derived. Spatial shapes of the modes, their frequencies, and coherent growth rates are explored. The Landau damping rates are also found. Suppression of the transverse mode coupling instability by the space charge is explained.

  8. Neodymium glass laser with a pulse energy of 220 J and a pulse repetition rate of 0.02 Hz

    SciTech Connect (OSTI)

    Kuzmin, A A; Kulagin, O V; Khazanov, Efim A; Shaykin, A A [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)] [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2013-07-31T23:59:59.000Z

    A compact neodymium glass laser with a pulse energy of 220 J and a record-high pulse repetition rate of 0.02 Hz (pulse duration 30 ns) is developed. Thermally induced phase distortions are compensated using wave phase conjugation. The integral depolarisation of radiation is decreased to 0.4% by using linear compensation schemes. The second harmonic of laser radiation can be used for pumping Ti : sapphire multipetawatt complexes. (letters)

  9. Two-gigawatt burst-mode operation of the intense microwave prototype (IMP) free-electron laser (FEL) for the microwave tokamak experiment (MTX)

    SciTech Connect (OSTI)

    Felker, B.; Allen, S.; Bell, H. [and others

    1993-10-06T23:59:59.000Z

    The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the parameter space of the IMP FEL, and finally evaluate transmission and absorption in the MTX. Single-pulse operations were repeatable. After the MTX was shut down burst-mode operations were successful at 2 kHz. This paper will describe the IMP FEL, Microwave Transmission System to MTX, the diagnostics used for calorimetric measurements, and the operations of the entire Microwave system. A discussion of correlated and uncorrelated errors that affect FEL performance will be made Linear and non-linear absorption data of the microwaves in the MTX plasma will be presented.

  10. Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

    E-Print Network [OSTI]

    D. L. Moehring; B. B. Blinov; D. W. Gidley; R. N. Kohn Jr.; M. J. Madsen; T. D. Sanderson; R. S. Vallery; C. Monroe

    2005-05-15T23:59:59.000Z

    We report precision measurements of the excited state lifetime of the $5p$ $^2P_{1/2}$ and $5p$ $^2P_{3/2}$ levels of a single trapped Cd$^+$ ion. The ion is excited with picosecond laser pulses from a mode-locked laser and the distribution of arrival times of spontaneously emitted photons is recorded. The resulting lifetimes are 3.148 $\\pm$ 0.011 ns and 2.647 $\\pm$ 0.010 ns for $^2P_{1/2}$ and $^2P_{3/2}$ respectively. With a total uncertainty of under 0.4%, these are among the most precise measurements of any atomic state lifetimes to date.

  11. The BRAIN experiment, a bolometric interferometer dedicated to the CMB B-mode measurement

    E-Print Network [OSTI]

    Romain Charlassier; for the BRAIN Collaboration

    2008-05-29T23:59:59.000Z

    We present the BRAIN Experiment, a project of B-mode experiment using a novel technology, bolometric interferometry. This technique is a promising alternative to direct imaging experiments since it combines the advantages of interferometry in terms of systematic effects handling and those of bolometry in terms of sensitivity. We briefly introduce some of the bolometric interferometry key concepts and difficulties. We then give the specifications of the BRAIN future detector. A first module of the final instrument is planned to be installed at Dome C in 2010. We hope to constrain a tensor to scalar modes ratio of 0.01 with nine modules and one effective year of data. BRAIN is a collaboration between France, Italy and United Kingdom.

  12. Plasma Modes Along the Open Field Lines of a Neutron Star

    E-Print Network [OSTI]

    U. A. Mofiz; B. J. Ahmedov

    2007-05-30T23:59:59.000Z

    We consider electrostatic plasma modes along the open field lines of a rotating neutron star. Goldreich-Julian charge density in general relativity is analyzed for the neutron star with zero inclination. It is found that the charge density is maximum at the polar cap and it remains almost same in certain extended region of the pole. For a steady state Goldreich-Julian charge density we found the usual plasma oscillation along the field lines; plasma frequency resembles to the gravitational redshift close to the Schwarzschild radius. We study the nonlinear plasma mode along the field lines. From the system of equations under general relativity, a second order differential equation is derived. The equation contains a term which describes the growing plasma modes near Schwarzschild radius in a black hole environment. The term vanishes with the distance far away from the gravitating object. For initially zero potential and field on the surface of a neutron star, Goldreich-Julian charge density is found to create the plasma mode, which is enhanced and propagates almost without damping along the open field lines. We briefly outline our plan to extend the work for studying soliton propagation along the open field lines of strongly gravitating objects.

  13. Effect of Nuclear Motion on Molecular High-Order Harmonics and on Generation of Attosecond Pulses in Intense Laser Pulses

    SciTech Connect (OSTI)

    Bandrauk, Andre D.; Chelkowski, Szczepan; Kawai, Shinnosuke; Lu, Huizhong [Departement de Chimie, Universite de Sherbrooke, Sherbrooke, Qc, J1K 2R1 (Canada)

    2008-10-10T23:59:59.000Z

    We calculate harmonic spectra and shapes of attosecond-pulse trains using numerical solutions of Non-Born-Oppenheimer time-dependent Shroedinger equation for 1D H{sub 2} molecules in an intense laser pulse. A very strong signature of nuclear motion is seen in the time profiles of high-order harmonics. In general the nuclear motion shortens the part of the attosecond-pulse train originating from the first electron contribution, but it may enhance the second electron contribution for longer pulses. The shape of time profiles of harmonics can thus be used for monitoring the nuclear motion.

  14. Ultra-wideband short-pulse radar with range accuracy for short range detection

    DOE Patents [OSTI]

    Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

    2014-10-07T23:59:59.000Z

    An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

  15. TERMINATION OF SIMPLY MODED WELLTYPED LOGIC PROGRAMS

    E-Print Network [OSTI]

    Giesl, Juergen

    TERMINATION OF SIMPLY MODED WELL­TYPED LOGIC PROGRAMS UNDER TABLED EXECUTION MECHANISM Sofie mechanism for logic programs. In particular, tabled execution of logic programs terminates more often than execution based on SLD­resolution. So, if a program can be proven to terminate under SLD­resolution (by one

  16. Standby and Off-Mode Energy Losses

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Standby and Off-Mode Energy Losses In New Appliances Measured in Shops #12;ISBN: 978 with the University of Coimbra. Its research interests include energyefficient technologies, renewable energies, and energy planning. Recent work includes the coordination of several European projects on market

  17. Do red giants have short mode lifetimes?

    E-Print Network [OSTI]

    D. Stello; H. Kjeldsen; T. R. Bedding; D. Buzasi

    2005-10-18T23:59:59.000Z

    We show evidence that the red giant star ksi Hya has an oscillation mode lifetime, tau, of about 2 days significantly shorter than predicted by theory (tau = 17 days, Houdek & Gough 2002). If this is a general trend of red giants it would limit the prospects of asteroseismology on these stars because of poor coherence of the oscillations.

  18. Psychological Insights on Transportation Mode Choice

    E-Print Network [OSTI]

    Bertini, Robert L.

    transportation modes such as bicycles, car sharing, and mass transit. Case studies were conducted with currentAlternatives to single occupancy vehicles:occupancy vehicles: Bicycles Buses Light rail Car sharing Car pooling Photo a car..." (TriMet Journal, March 6, 2006) He had been waiting for the train at the MAX platform (at 6 PM

  19. Thermionic converter in load-switching mode

    SciTech Connect (OSTI)

    Mendel'baum, M.A.; Es'kov, V.D.

    1983-01-01T23:59:59.000Z

    An electrical equivalent circuit is proposed for a thermionic electrogenerating element. It is suitable for calculation of transients in load-switching mode. Formulas are given for estimating circuit parameters. A sample numerical calculation is given for the transient between no-load and short-circuit regimes. The results may be employed to identify experimental data in the frequency domain.

  20. HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS

    E-Print Network [OSTI]

    McCluskey, Matthew

    HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS M.D. MCCLUSKEY* University) spectroscopy of hydrogen and deuterium in GaP, AlSb, ZnSe, and GaN has provided important information about the structures of dopant- hydrogen complexes and their interaction with the host lattice. In GaN:Mg, for example

  1. Nonlinearly driven harmonics of Alfvén modes

    SciTech Connect (OSTI)

    Zhang, B., E-mail: bozhang@austin.utexas.edu; Breizman, B. N.; Zheng, L. J.; Berk, H. L. [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States)] [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-01-15T23:59:59.000Z

    In order to study the leading order nonlinear magneto-hydrodynamic (MHD) harmonic response of a plasma in realistic geometry, the AEGIS code has been generalized to account for inhomogeneous source terms. These source terms are expressed in terms of the quadratic corrections that depend on the functional form of a linear MHD eigenmode, such as the Toroidal Alfvén Eigenmode. The solution of the resultant equation gives the second order harmonic response. Preliminary results are presented here.

  2. Calendar Year study term 1

    E-Print Network [OSTI]

    Dawson, Jeff W.

    laboratory and research facilities Carleton's laboratory and computer facilities are unparalleled association with, government organizations such as the National Research Council Canada. Your co Study Term 5 Dynamics of Machinery Mechanics of Solids II Systems and Simulation Electrical

  3. Short-Term Energy Outlook

    U.S. Energy Information Administration (EIA) Indexed Site

    Chart Gallery for April 2015 Short-Term Energy Outlook U.S. Energy Information Administration Independent Statistics & Analysis 0 20 40 60 80 100 120 140 160 180 200 220 Jan 2014...

  4. Short-Term Energy Outlook

    Gasoline and Diesel Fuel Update (EIA)

    day Forecast -1.0 2012 2013 2014 OPEC countries North America Russia and Caspian Sea Latin America North Sea Other Non-OPEC Source: Short-Term Energy Outlook, November 2013 -1 0...

  5. CMB B-modes, spinorial space-time and Pre-Big Bang (II)

    E-Print Network [OSTI]

    Luis Gonzalez-Mestres

    2014-08-02T23:59:59.000Z

    The BICEP2 collaboration reported recently a B-mode polarization of the cosmic microwave background (CMB) radiation inconsistent with the null hypothesis at a significance of > 5 {\\sigma}. This result has been often interpreted as a signature of primordial gravitational waves from cosmic inflation, even if actually polarized dust emission may be at the origin of such a signal. Even assuming that part of this CMB B-mode polarization really corresponds to the early Universe dynamics, its interpretation in terms of inflation and primordial gravitational waves is not the only possible one. Alternative cosmologies such as pre-Big Bang patterns and the spinorial space-time (SST) we introduced in 1996-97 can naturally account for such CMB B-modes. In particular, the SST automatically generates a privileged space direction (PSD) whose existence may have been confirmed by Planck data. If such a PSD exists, it seems normal to infer that vector perturbations have been present in the early Universe leading to CMB B-modes in suitable cosmological patterns. Inflation would not be required to explain the BICEP2 result assuming it really contains a primordial signal. More generally, pre-Big Bang cosmologies can also generate gravitational waves in the early Universe without any need for cosmic inflation. We further discuss here possible alternatives to the inflationary interpretation of a primordial B-mode polarization of cosmic microwave background radiation.

  6. Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias

    SciTech Connect (OSTI)

    Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Macheret, Sergey O. [Lockheed Martin Aeronautics Company, Palmdale, California 93599 (United States)

    2008-08-15T23:59:59.000Z

    Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

  7. Ultrashort pulse laser deposition of thin films

    DOE Patents [OSTI]

    Perry, Michael D. (Livermore, CA); Banks, Paul S. (Livermore, CA); Stuart, Brent C. (Fremont, CA)

    2002-01-01T23:59:59.000Z

    Short pulse PLD is a viable technique of producing high quality films with properties very close to that of crystalline diamond. The plasma generated using femtosecond lasers is composed of single atom ions with no clusters producing films with high Sp.sup.3 /Sp.sup.2 ratios. Using a high average power femtosecond laser system, the present invention dramatically increases deposition rates to up to 25 .mu.m/hr (which exceeds many CVD processes) while growing particulate-free films. In the present invention, deposition rates is a function of laser wavelength, laser fluence, laser spot size, and target/substrate separation. The relevant laser parameters are shown to ensure particulate-free growth, and characterizations of the films grown are made using several diagnostic techniques including electron energy loss spectroscopy (EELS) and Raman spectroscopy.

  8. Bipolar pulse field for magnetic refrigeration

    DOE Patents [OSTI]

    Lubell, M.S.

    1994-10-25T23:59:59.000Z

    A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies. 2 figs.

  9. Supergiant Pulses from Extragalactic Neutron Stars

    E-Print Network [OSTI]

    Cordes, J M

    2015-01-01T23:59:59.000Z

    We evaluate the hypothesis that extragalactic radio bursts originate from neutron stars. These could be active pulsars or dormant, slowly spinning objects, but the different population distances for these two classes require correspondingly different contributions to burst dispersion measures from any host or intervening galaxies combined with the intergalactic medium. The large, apparent burst rate $\\sim 10^4~$ sky$^{-1}~$ day$^{-1}$ is comparable to the core-collapse supernova rate in a Hubble volume and can be accommodated by a single burst per object in the resulting large reservoir of $\\sim 10^{17}~$ neutron stars. A smaller population distance requires more bursts per object but the likelihood of seeing repeated bursts from any single object is extremely low on human timescales. Gravitational microlensing could play a role for high redshift sources. Extrapolation of the Crab pulsar's giant pulses --- exemplars of coherent, high brightness temperature radiation --- to a rate of one per $10^3~$yr yields a...

  10. Pulse combusted acoustic agglomeration apparatus and process

    DOE Patents [OSTI]

    Mansour, Momtaz N. (Columbia, MD)

    1993-01-01T23:59:59.000Z

    An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

  11. Pulse combusted acoustic agglomeration apparatus and process

    DOE Patents [OSTI]

    Mansour, Momtaz N. (Columbia, MD); Chandran, Ravi (Ellicott City, MD)

    1994-01-01T23:59:59.000Z

    An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance agglomeration of particulates which may be collected and removed using a conventional separation apparatus. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, added particulates may include a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

  12. RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium

    E-Print Network [OSTI]

    Killian, Thomas C.

    RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta A Thesis Submitted April, 2004 #12;2 #12;#12;iii ABSTRACT Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta that is used to make ultracold strontium plasma. In order to make ultracold plasma, we cool and trap strontium

  13. PulsedPower Transient Plasma: Energy, Engines, and

    E-Print Network [OSTI]

    Levi, Anthony F. J.

    1Gundersen PulsedPower USC Transient Plasma: Energy, Engines, and Aerospace Applications USC: Dan phase prior to equilibration of the electron energy distribution It is studied for applications Biomedical (Cancer) A Little Wine Catalyst Yung-Hsu Andy Kuthi #12;3Gundersen PulsedPower USC Transient

  14. Beams 92: Proceedings. Volume 1: Invited papers, pulsed power

    SciTech Connect (OSTI)

    Mosher, D.; Cooperstein, G. [eds.] [Naval Research Lab., Washington, DC (United States)

    1993-12-31T23:59:59.000Z

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere.

  15. Raman Amplification of Laser Pulses in Microcapillary Plasmas

    E-Print Network [OSTI]

    of overcoming the power limit of current chirped-pulse-amplification (CPA) CP641, X-Ray Lasers 2002: 8th International Conference on X-Ray Lasers, edited by J. J. Rocca et al. > 2002American Institute of Physics 0 of the optics. Such Raman amplifiers can be useful to produce ultra-intense laser pulses for pumping soft x-ray

  16. DIRECT SPACE-TO-TIME PULSE SHAPING FOR ULTRAFAST OPTICAL

    E-Print Network [OSTI]

    Purdue University

    DIRECT SPACE-TO-TIME PULSE SHAPING FOR ULTRAFAST OPTICAL WAVEFORM GENERATION A Thesis Submitted ago. To the students, past and present, post-docs, and visitors of the Ultrafast Optics & Optical me what it is that I love about this work. The experimental optical pulse train generation devices

  17. Searching for Transient Pulses with the ETA Radio Telescope

    E-Print Network [OSTI]

    Ellingson, Steven W.

    frequency pulses from transient events such as gamma ray bursts and primordial black hole explosions ray bursts (GRBs). PBHs are postulated to arise from density fluctu- ations in the early universe for these pulses include the ex- plosion of primordial black holes (PBHs) and prompt emission associated with gamma

  18. Isolated attosecond pulses using a detuned second-harmonic field

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Isolated attosecond pulses using a detuned second-harmonic field Hamed Merdji,1,2, * Thierry 2 . The slight detuning of the second harmonic is used to break the symmetry of the electric field-order harmonics generation (HHG) of intense laser pulses in gases is attracting much attention due to both

  19. Multiple pulse resonantly enhanced laser plasma wakefield acceleration

    SciTech Connect (OSTI)

    Corner, L.; Walczak, R.; Nevay, L. J.; Dann, S.; Hooker, S. M.; Bourgeois, N.; Cowley, J. [John Adams Institute for Accelerator Science, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom)

    2012-12-21T23:59:59.000Z

    We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates.

  20. Pulse thermal processing of functional materials using directed plasma arc

    DOE Patents [OSTI]

    Ott, Ronald D. (Knoxville, TN); Blue, Craig A. (Knoxville, TN); Dudney, Nancy J. (Knoxville, TN); Harper, David C. (Kingston, TN)

    2007-05-22T23:59:59.000Z

    A method of thermally processing a material includes exposing the material to at least one pulse of infrared light emitted from a directed plasma arc to thermally process the material, the pulse having a duration of no more than 10 s.

  1. Ultrashort-pulse laser generated nanoparticles of energetic materials

    DOE Patents [OSTI]

    Welle, Eric J. (Niceville, NM); Tappan, Alexander S. (Albuquerque, NM); Palmer, Jeremy A. (Albuquerque, NM)

    2010-08-03T23:59:59.000Z

    A process for generating nanoscale particles of energetic materials, such as explosive materials, using ultrashort-pulse laser irradiation. The use of ultrashort laser pulses in embodiments of this invention enables one to generate particles by laser ablation that retain the chemical identity of the starting material while avoiding ignition, deflagration, and detonation of the explosive material.

  2. Conditions for two-photon interference with coherent pulses

    E-Print Network [OSTI]

    Yong-Su Kim; Oliver Slattery; Paulina S. Kuo; Xiao Tang

    2013-06-27T23:59:59.000Z

    We study the conditions for two-photon classical interference with coherent pulses. We find that the temporal overlap between optical pulses is not required for interference However, coherence within the same inputs is found to be essential for the interference.

  3. Plasmon enhanced photoelectron spectroscopy and the generation of isolated attosecond XUV pulses for use with condensed matter targets

    E-Print Network [OSTI]

    Nagel, Phillip Michael

    2011-01-01T23:59:59.000Z

    experiments, an ultrafast laser pulse is used to launch ahigh intensity, ultrafast laser pulses. Lasers that generateexcited directly by ultrafast laser pulses without requiring

  4. Lead acid battery pulse discharge investigation. Final report

    SciTech Connect (OSTI)

    Dowgiallo, E

    1980-04-01T23:59:59.000Z

    The effects of high current pulses caused by electric vehicle silicon-controlled rectifier and transistor chopper controllers on battery energy, lifetime, and microstructure were studied. Test equipment and results are described. It was found that the energy of improved golf cart-type batteries deteriorated under pulsed conditions by about 10% with respect to dc conditions for pulses between 16 and 333 Hz - no difference was noted above 333 Hz. Frequencies and duty cycles characteristic of electric vehicle controllers produce ampere-hour capacities similar in magnitude to dc discharges of the same average currents. The amount of positive plate corrosion under pulsed conditions was about twice that ot the unpulsed. Unusually large lead sulfate crystals were found in isolated colonies in pulsed plates, whereas a battery that had been discharged each cycle at an equivalent steady state did not show these large crystals. 5 figures, 3 tables. (RWR)

  5. Plasma Switch for High-Power Active Pulse Compressor

    SciTech Connect (OSTI)

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

    2013-11-04T23:59:59.000Z

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

  6. ON THE NATURE OF OFF-PULSE EMISSION FROM PULSARS

    SciTech Connect (OSTI)

    Basu, Rahul; Mitra, Dipanjan [National Centre for Radio Astrophysics, P.O. Bag 3, Pune University Campus, Pune 411 007 (India); Athreya, Ramana, E-mail: rbasu@ncra.tifr.res.in, E-mail: dmitra@ncra.tifr.res.in, E-mail: rathreya@iiserpune.ac.in [Indian Institute of Science Education Research (IISER)-Pune, 900, NCL Innovation Park, Homi Bhabha Road, Pune, 411 008 (India)

    2012-10-20T23:59:59.000Z

    In our earlier studies, we reported the detection of off-pulse emission from two long-period pulsars B0525+21 and B2045-16. The pulsars were observed at a single epoch using the 325 MHz frequency band of the Giant Meterwave Radio Telescope (GMRT). In this paper, we report a detailed study of the off-pulse emission from these two pulsars using multiple observations at two different frequencies, 325 MHz and 610 MHz bands of GMRT. We report detection of off-pulse emission during each observation and based on the scintillation effects and spectral index of off-pulse emission we conclude a magnetospheric origin. The magnetospheric origin of off-pulse emission gives rise to various interesting possibilities about its emission mechanism and raises questions about the structure of the magnetosphere.

  7. High-performance laser processing using manipulated ultrafast laser pulses

    SciTech Connect (OSTI)

    Sugioka, Koji; Cheng Ya; Xu Zhizhan; Hanada, Yasutaka; Midorikawa, Katsumi [RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan); State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (China); RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan)

    2012-07-30T23:59:59.000Z

    We employ manipulated ultrafast laser pulses to realize microprocessing with high-performance. Efficient microwelding of glass substrates by irradiation by a double-pulse train of ultrafast laser pulses is demonstrated. The bonding strength of two photostructurable glass substrates welded by double-pulse irradiation was evaluated to be 22.9 MPa, which is approximately 22% greater than that of a sample prepared by conventional irradiation by a single pulse train. Additionally, the fabrication of hollow microfluidic channels with a circular cross-sectional shape embedded in fused silica is realized by spatiotemporally focusing the ultrafast laser beam. We show both theoretically and experimentally that the spatiotemporal focusing of ultrafast laser beam allows for the creation of a three-dimensionally symmetric spherical peak intensity distribution at the focal spot.

  8. High-voltage air-core pulse transformers

    SciTech Connect (OSTI)

    Rohwein, G. J.

    1981-01-01T23:59:59.000Z

    General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

  9. Molecular spinning by a chiral train of short laser pulses

    E-Print Network [OSTI]

    Johannes Floß; Ilya Sh. Averbukh

    2012-10-31T23:59:59.000Z

    We provide a detailed theoretical analysis of molecular rotational excitation by a chiral pulse train -- a sequence of linearly polarised pulses with the polarisation direction rotating from pulse to pulse by a controllable angle. Molecular rotation with a preferential rotational sense (clockwise or counter-clockwise) can be excited by this scheme. We show that the directionality of the rotation is caused by quantum interference of different excitation pathways. The chiral pulse train is capable of selective excitation of molecular isotopologues and nuclear spin isomers in a mixture. We demonstrate this using 14N2 and 15N2 as examples for isotopologues, and para- and ortho-nitrogen as examples for nuclear spin isomers.

  10. Term statistics Zipf's law text statistics

    E-Print Network [OSTI]

    Lu, Jianguo

    Term statistics Zipf's law text statistics October 20, 2014 text statistics 1 / 19 #12;Term statistics Zipf's law Overview 1 Term statistics 2 Zipf's law text statistics 2 / 19 #12;Term statistics Zipf's law Outline 1 Term statistics 2 Zipf's law text statistics 3 / 19 #12;Term statistics Zipf's law Model

  11. Abstract--In the design of a spaceborne Synthetic Aperture RADAR mission with multiple modes and swaths, like the

    E-Print Network [OSTI]

    Gesbert, David

    the modes. Index Terms-- Synthetic Aperture Radar, STRIPMAP, TOPSAR. Conference topic: SAR/ISAR I Sophia-Antipolis cedex, France. mail: lorenzo.maggi@eurecom.fr calibration and the processing. In order of a spaceborne SAR. Let us refer to the geometry of Fig. 1.a, where we assumed for simplicity flat earth

  12. Radical Matter: Materiality in Postwar and Contemporary American Mixed Mode Poetry

    E-Print Network [OSTI]

    Wang, Sophia

    2012-01-01T23:59:59.000Z

    Mixed  Mode  Poetry   By   Sophia  Wang   A  dissertation  Mode  Poetry   by   Sophia  Wang   Doctor  of  Philosophy  

  13. 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 into a supersonic helium gas jet are used to ionize liquid water. The decay of the hydrated electrons produced electron generator is shown, for the first time, to produce sufficient charge to conduct time resolved

  14. Mode-synthesizing atomic force microscopy and mode-synthesizing sensing

    DOE Patents [OSTI]

    Passain, Ali; Thundat, Thomas George; Tetard, Laurene

    2014-07-22T23:59:59.000Z

    A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

  15. Electron acceleration by Z-mode and whistler-mode waves

    SciTech Connect (OSTI)

    Lee, K. H. [Institute of Space Science, National Central University, Zhongli, Taiwan (China)] [Institute of Space Science, National Central University, Zhongli, Taiwan (China); Omura, Y. [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan)] [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan); Lee, L. C. [Institute of Space Science, National Central University, Zhongli, Taiwan (China) [Institute of Space Science, National Central University, Zhongli, Taiwan (China); Institute of Earth Science, Academia Sinica, Nankang, Taiwan (China)

    2013-11-15T23:59:59.000Z

    We carried out a series of particle simulations to study electron acceleration by Z-mode and whistler-mode waves generated by an electron ring distribution. The electron ring distribution leads to excitations of X-mode waves mainly in the perpendicular direction, Z-mode waves in the perpendicular and parallel directions, and whistler-mode waves mainly in the parallel direction. The parallel Z- and whistler-mode waves can lead to an effective acceleration of ring electrons. The electron acceleration is mainly determined by the wave amplitude and phase velocity, which in turn is affected by the ratio of electron plasma to cyclotron frequencies. For the initial kinetic energy ranging from 100 to 500 keV, the peak energy of the accelerated electrons is found to reach 2–8 times the initial kinetic energy. We further study the acceleration process by test-particle calculations in which electrons interact with one, two, or four waves. The electron trajectories in the one-wave case are simple diffusion curves. In the multi-wave cases, electrons are accelerated simultaneously by counter-propagating waves and can have a higher final energy.

  16. Comparison of H-Mode Plasmas Diverted to Solid and Liquid Lithium Surfaces

    SciTech Connect (OSTI)

    R. Kaita, et. al.

    2012-07-20T23:59:59.000Z

    Experiments were conducted with a Liquid Lithium Divertor (LLD) in NSTX. Among the goals was to use lithium recoating to sustain deuterium (D) retention by a static liquid lithium surface, approximating the ability of flowing liquid lithium to maintain chemical reactivity. Lithium evaporators were used to deposit lithium on the LLD surface. Improvements in plasma edge conditions were similar to those with lithiated graphite plasma-facing components (PFCs), including an increase in confinement over discharges without lithiumcoated PFCs and ELM reduction during H-modes. With the outer strike point on the LLD, the D retention in the LLD was about the same as that for solid lithium coatings on graphite, or about two times that achieved without lithium PFC coatings. There were also indications of contamination of the LLD surface, possibly due erosion and redeposition of carbon from PFCs. Flowing lithium may thus be needed for chemically active PFCs during long-pulse operation.

  17. Dynamics of local micro-breakdown in the Geiger mode of avalanche photodiodes

    SciTech Connect (OSTI)

    Verhovtseva, A. V., E-mail: alevteena@gmail.com; Gergel, V. A. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)], E-mail: gergel@mail.cplire.ru

    2009-07-15T23:59:59.000Z

    Mathematical modeling methods were used to study the dynamics of micro-breakdown development in structures of silicon avalanche photodiodes. The constructed model considers the locality of the avalanchexs multiplication region appearing during single photon absorption and the delay of the avalanchexs current spreading over the rear electrode of the diode. The calculations showed two different phases of transient process of the formation of the electrical signal, i.e., the rapid and slow ones due to current spreading and ordinary RC recharge, respectively. The load resistances required to implement the pulsed mode of operation of the structures of the avalanche photodiode were calculated for a series of actual diode capacitances and spreading resistances of the rear electrode.

  18. Tuning the external optical feedback-sensitivity of a passively mode-locked quantum dot laser

    SciTech Connect (OSTI)

    Raghunathan, R., E-mail: raghunat@vt.edu; Kovanis, V.; Lester, L. F. [Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, 302 Whittemore Hall, Blacksburg, Virginia 24061 (United States); Grillot, F. [Télécom ParisTech, Ecole Nationale Supérieure des Télécommunications, CNRS LTCI, 46 rue Barrault, 75634 Paris Cedex 13 (France); Mee, J. K.; Murrell, D. [Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)

    2014-07-28T23:59:59.000Z

    The external optical feedback-sensitivity of a two-section, passively mode-locked quantum dot laser operating at elevated temperature is experimentally investigated as a function of absorber bias voltage. Results show that the reverse-bias voltage on the absorber has a direct impact on the damping rate of the free-running relaxation oscillations of the optical signal output, thereby enabling interactive external control over the feedback-response of the device, even under the nearly resonant cavity configuration. The combination of high temperature operation and tunable feedback-sensitivity is highly promising from a technological standpoint, in particular, for applications requiring monolithic integration of multi-component architectures on a single chip in order to accomplish, for instance, the dual-objectives of stable pulse quality and isolation from parasitic reflections.

  19. Phase modulation mode of scanning ion conductance microscopy

    SciTech Connect (OSTI)

    Li, Peng; Zhang, Changlin [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Lianqing, E-mail: lqliu@sia.cn, E-mail: gli@engr.pitt.edu; Wang, Yuechao; Yang, Yang [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Guangyong, E-mail: lqliu@sia.cn, E-mail: gli@engr.pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)

    2014-08-04T23:59:59.000Z

    This Letter reports a phase modulation (PM) mode of scanning ion conductance microscopy. In this mode, an AC current is directly generated by an AC voltage between the electrodes. The portion of the AC current in phase with the AC voltage, which is the current through the resistance path, is modulated by the tip-sample distance. It can be used as the input of feedback control to drive the scanner in Z direction. The PM mode, taking the advantages of both DC mode and traditional AC mode, is less prone to electronic noise and DC drift but maintains high scanning speed. The effectiveness of the PM mode has been proven by experiments.

  20. Geodesic stability, Lyapunov exponents and quasinormal modes

    E-Print Network [OSTI]

    Vitor Cardoso; Alex S. Miranda; Emanuele Berti; Helvi Witek; Vilson T. Zanchin

    2009-03-12T23:59:59.000Z

    Geodesic motion determines important features of spacetimes. Null unstable geodesics are closely related to the appearance of compact objects to external observers and have been associated with the characteristic modes of black holes. By computing the Lyapunov exponent, which is the inverse of the instability timescale associated with this geodesic motion, we show that, in the eikonal limit, quasinormal modes of black holes in any dimensions are determined by the parameters of the circular null geodesics. This result is independent of the field equations and only assumes a stationary, spherically symmetric and asymptotically flat line element, but it does not seem to be easily extendable to anti-de Sitter spacetimes. We further show that (i) in spacetime dimensions greater than four, equatorial circular timelike geodesics in a Myers-Perry black hole background are unstable, and (ii) the instability timescale of equatorial null geodesics in Myers-Perry spacetimes has a local minimum for spacetimes of dimension d > 5.

  1. ITER L-Mode Confinement Database

    SciTech Connect (OSTI)

    S.M. Kaye and the ITER Confinement Database Working Group

    1997-10-01T23:59:59.000Z

    This paper describes the content of an L-mode database that has been compiled with data from Alcator C-Mod, ASDEX, DIII, DIII-D, FTU, JET, JFT-2M, JT-60, PBX-M, PDX, T-10, TEXTOR, TFTR, and Tore-Supra. The database consists of a total of 2938 entries, 1881 of which are in the L-phase while 922 are ohmically heated (OH) only. Each entry contains up to 95 descriptive parameters, including global and kinetic information, machine conditioning, and configuration. The paper presents a description of the database and the variables contained therein, and it also presents global and thermal scalings along with predictions for ITER. The L-mode thermal confinement time scaling was determined from a subset of 1312 entries for which the thermal confinement time scaling was provided.

  2. Tensor modes on the string theory landscape

    E-Print Network [OSTI]

    Alexander Westphal

    2012-12-22T23:59:59.000Z

    We attempt an estimate for the distribution of the tensor mode fraction $r$ over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards large-field or small-field inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for small-field vs large-field inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped Calabi-Yau flux compactifications of type IIB string theory.

  3. Disordered Optical Modes for Photon Management

    E-Print Network [OSTI]

    Vynck, Kevin; Riboli, Francesco; Wiersma, Diederik S

    2012-01-01T23:59:59.000Z

    Wave transport in disordered systems is a vast research topic, ranging from electrons in semiconductors, to light in random dielectrics, to cold atoms in laser speckles. In optics, light transport is conveyed by random electromagnetic modes and the wave can be localized about a point or extended throughout the system, depending on disorder strength, structural correlations and dimensionality of the system. Light localization phenomena are more dominantly present in two-dimensional systems than in three-dimensional ones and their optical modes can be tailored to a greater extent. Here, we show that it is possible to make use of the properties of lower-dimensional disordered structures to obtain photon management in three-dimensional space. More particularly, we argue that two-dimensional disorder and wave interferences can be exploited to improve the performance of light absorbers or emitters. Our findings have direct applications for enhancing the absorption efficiency of third-generation solar cells in a rel...

  4. The impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants

    SciTech Connect (OSTI)

    Latkowski, J.F. [Lawrence Livermore National Lab., CA (United States); Sanz, J. [Universidad Politecnica de Madrid (Spain); Vujic, J.L. [California Univ., Berkeley, CA (United States)

    1996-06-26T23:59:59.000Z

    Inertial fusion energy (IFE) and magnetic fusion energy (MFE) power plants will probably operate in a pulsed mode. The two different schemes, however, will have quite different time periods. Typical repetition rates for IFE power plants will be 1-5 Hz. MFE power plants will ramp up in current for about 1 hour, shut down for several minutes, and repeat the process. Traditionally, activation calculations for IFE and MFE power plants have assumed continuous operation and used either the ``steady state`` (SS) or ``equivalent steady state`` (ESS) approximations. It has been suggested recently that the SS and ESS methods may not yield accurate results for all radionuclides of interest. The present work expands that of Sisolak, et al. by applying their formulae to conditions which might be experienced in typical IFE and MFE power plants. In addition, complicated, multi-step reaction/decay chains are analyzed using an upgraded version of the ACAB radionuclide generation/depletion code. Our results indicate that the SS method is suitable for application to MFE power plant conditions. We also find that the ESS method generates acceptable results for radionuclides with half-lives more than a factor of three greater than the time between pulses. For components that are subject to 0.05 Hz (or more frequent) irradiation (such as coolant), use of the ESS method is recommended. For components or materials that are subject to less frequent irradiation (such as high-Z target materials), pulsed irradiation calculations should be used.

  5. Stabilizing windings for tilting and shifting modes

    DOE Patents [OSTI]

    Jardin, Stephen C. (Princeton, NJ); Christensen, Uffe R. (Princeton, NJ)

    1984-01-01T23:59:59.000Z

    This invention relates to passive conducting loops for stabilizing a plasma ring against unstable tilting and/or shifting modes. To this end, for example, plasma ring in a spheromak is stabilized by a set of four figure-8 shaped loops having one pair on one side of the plasma and one pair on the other side with each pair comprising two loops whose axes are transverse to each other.

  6. Light plasmon mode in the CFL phase

    E-Print Network [OSTI]

    Malekzadeh, H; Rischke, Dirk H.

    2007-01-01T23:59:59.000Z

    The self-energies and the spectral densities of longitudinal and transverse gluons at zero temperature in the color-flavor-locked (CFL) phase are calculated. There appears a collective excitation, a light plasmon, at energies smaller than two times the gap parameter and momenta smaller than about eight times the gap. The minimum in the dispersion relation of this mode at some nonzero value of momentum corresponds to the van Hove singularity.

  7. Light plasmon mode in the CFL phase

    E-Print Network [OSTI]

    H. Malekzadeh; Dirk H. Rischke

    2006-11-10T23:59:59.000Z

    The self-energies and the spectral densities of longitudinal and transverse gluons at zero temperature in the color-flavor-locked (CFL) phase are calculated. There appears a collective excitation, a light plasmon, at energies smaller than two times the gap parameter and momenta smaller than about eight times the gap. The minimum in the dispersion relation of this mode at some nonzero value of momentum corresponds to the van Hove singularity.

  8. Compression mode resonances in Zr-90

    E-Print Network [OSTI]

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

    2004-01-01T23:59:59.000Z

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

  9. Tunable THz Generation by the Interaction of a Super-luminous Laser Pulse with Biased Semiconductor Plasma

    SciTech Connect (OSTI)

    Papadopoulos, K. [BAE Systems-ATI, University of Maryland, College Park MD 20742 (United States); Zigler, A. [BAE Systems-ATI, Hebrew University (Israel)

    2006-01-03T23:59:59.000Z

    Terahertz (THz) radiation is electromagnetic radiation in the range between several hundred and a few thousand GHz. It covers the gap between fast-wave electronics (millimeter waves) and optics (infrared). This spectral region offers enormous potential for detection of explosives and chemical/biological agents, non-destructive testing of non-metallic structural materials and coatings of aircraft structures, medical imaging, bio-sensing of DNA stretching modes and high-altitude secure communications. The development of these applications has been hindered by the lack of powerful, tunable THz sources with controlled waveform. The need for such sources is accentuated by the strong, but selective absorption of THz radiation during transmission through air with high vapor content. The majority of the current experimental work relies on time-domain spectroscopy using fast electrically biased photoconductive sources in conjunction with femto-second mode-locked Ti:Sapphire lasers. These sources known as Large Aperture Photoconductive Antennas (LAPA) have very limited tunability, relatively low upper bound of power and no bandwidth control. The paper presents a novel source of THz radiation known as Miniature Photoconductive Capacitor Array (MPCA). Experiments demonstrated tunability between .1 - 2 THz, control of the relative bandwidth {delta}f/f between .5-.01, and controlled pulse length and pulse waveform (temporal shape, chirp, pulse-to-pulse modulation etc.). Direct scaling from the current device indicates efficiency in excess of 30% at 1 THz with 1/f2 scaling at higher frequencies, peak power of 100 kW and average power between .1-1 W. The physics underlying the MPCA is the interaction of a super-luminous ionization front generated by the oblique incidence of a Ti:Sapphire laser pulse on a semiconductor crystal (ZnSe) biased with an alternating electrostatic field, similar to that of a frozen wave generator. It is shown theoretically and experimentally that the interaction results in the emission of an electromagnetic wave at the plasma frequency of the ionization front. The device resembles the well-known DARC plasma device with two significant differences. First, the frozen wave is on a semiconductor crystal and not on a gas (Azulene Vapor). Second, the ionizing front is super-luminous. These differences result in a device with superior tunability, efficiency, compactness and flexibility. The paper concludes with examples of THz imaging using the MPCA.

  10. A Her X-1 Turn-On: Using the pulse profile to probe the outer edge of an accretion disk

    E-Print Network [OSTI]

    M. Kuster; J. Wilms; R. Staubert; P. Risse; W. A. Heindl; R. Rothschild; N. I. Shakura; K. A. Postnov

    2002-03-13T23:59:59.000Z

    The X-ray binary pulsar Her X-1 shows a wide variety of long and short term variabilities in the X-ray light curve. The 35 d variability of the source is interpreted as the influence of a warped, inclined, and twisted accretion disk periodically covering the line of sight to the central neutron star. In 1997 September we observed the ``turn-on'' of a 35 d cycle with the Rossi X-ray Timing Explorer (RXTE). Spectral analysis reveals that during early phases of the turn-on the overall spectrum is composed of X-rays scattered into the line of sight plus heavily absorbed X-rays. This interpretation is consistent with the variation of the pulse profile observed at the same time. The overall shape of the pulse profile is not changing, but towards earlier phases of the turn-on the pulse signature is steadily ``washed out''. This behavior can be understood as an influence of scattering and absorption due to the presence of the accretion disk rim. Using a Monte Carlo code we simulate the influence of both processes on a time variable, beamed emission characteristic, similar to the pulse profile of Her X-1. By comparing the results of the simulation with the observed profiles we determine the amount of scattered radiation, absorbed radiation, and the size of the scattering region.

  11. The Burst Mode of Protostellar Accretion

    E-Print Network [OSTI]

    E. I. Vorobyov; Shantanu Basu

    2006-07-06T23:59:59.000Z

    We present new numerical simulations in the thin-disk approximation which characterize the burst mode of protostellar accretion. The burst mode begins upon the formation of a centrifugally balanced disk around a newly formed protostar. It is comprised of prolonged quiescent periods of low accretion rate (typically $\\la 10^{-7} \\Msun$ yr$^{-1}$) which are punctuated by intense bursts of accretion (typically $\\ga 10^{-4} \\Msun$ yr$^{-1}$, with duration $\\la 100$ yr) during which most of the protostellar mass is accumulated. The accretion bursts are associated with the formation of dense protostellar/protoplanetary embryos, which are later driven onto the protostar by the gravitational torques that develop in the disk. Gravitational instability in the disk, driven by continuing infall from the envelope, is shown to be an effective means of transporting angular momentum outward, and mass inward to the protostar. We show that the disk mass always remains significantly less than the central protostar mass throughout this process. The burst phenomenon is robust enough to occur for a variety of initial values of rotation rate, frozen-in (supercritical) magnetic field, and density-temperature relations. Even in cases where the bursts are nearly entirely suppressed, a moderate increase in cloud size or rotation rate can lead to vigorous burst activity. We conclude that most (if not all) protostars undergo a burst mode of evolution during their early accretion history, as inferred empirically from observations of FU Orionis variables.

  12. Pulse Jet Mixing Tests With Noncohesive Solids

    SciTech Connect (OSTI)

    Meyer, Perry A.; Bamberger, Judith A.; Enderlin, Carl W.; Fort, James A.; Wells, Beric E.; Sundaram, S. K.; Scott, Paul A.; Minette, Michael J.; Smith, Gary L.; Burns, Carolyn A.; Greenwood, Margaret S.; Morgen, Gerald P.; Baer, Ellen BK; Snyder, Sandra F.; White, Michael; Piepel, Gregory F.; Amidan, Brett G.; Heredia-Langner, Alejandro; Bailey, Sharon A.; Bower, John C.; Denslow, Kayte M.; Eakin, David E.; Elmore, Monte R.; Gauglitz, Phillip A.; Guzman, Anthony D.; Hatchell, Brian K.; Hopkins, Derek F.; Hurley, David E.; Johnson, Michael D.; Kirihara, Leslie J.; Lawler, Bruce D.; Loveland, Jesse S.; Mullen, O Dennis; Pekour, Mikhail S.; Peters, Timothy J.; Robinson, Peter J.; Russcher, Michael S.; Sande, Susan; Santoso, Christian; Shoemaker, Steven V.; Silva, Steve M.; Smith, Devin E.; Su, Yin-Fong; Toth, James J.; Wiberg, John D.; Yu, Xiao-Ying; Zuljevic, Nino

    2009-05-11T23:59:59.000Z

    This report summarizes results from pulse jet mixing (PJM) tests with noncohesive solids in Newtonian liquid conducted during FY 2007 and 2008 to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant (WTP). Tests were conducted at three geometric scales using noncohesive simulants. The test data were used to independently develop mixing models that can be used to predict full-scale WTP vessel performance and to rate current WTP mixing system designs against two specific performance requirements. One requirement is to ensure that all solids have been disturbed during the mixing action, which is important to release gas from the solids. The second requirement is to maintain a suspended solids concentration below 20 weight percent at the pump inlet. The models predict the height to which solids will be lifted by the PJM action, and the minimum velocity needed to ensure all solids have been lifted from the floor. From the cloud height estimate we can calculate the concentration of solids at the pump inlet. The velocity needed to lift the solids is slightly more demanding than "disturbing" the solids, and is used as a surrogate for this metric. We applied the models to assess WTP mixing vessel performance with respect to the two perform¬ance requirements. Each mixing vessel was evaluated against these two criteria for two defined waste conditions. One of the wastes was defined by design limits and one was derived from Hanford waste characterization reports. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy the performance criteria used for any of the conditions evaluated. The remaining three vessel types provide varying assessments when the different particle characteristics are evaluated. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy the performance criteria used for any of the conditions evaluated. The remaining three vessel types provide varying assessments when the different particle characteristics are evaluated. The HLP-022 vessel was also evaluated using 12 m/s pulse jet velocity with 6-in. nozzles, and this design also did not satisfy the criteria for all of the conditions evaluated.

  13. E-Print Network 3.0 - alternate pulse current Sample Search Results

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

    larger. To prevent the heat pulse from... on the complement channel of the pulse ... Source: Balandin, Alexander- Department of Electrical Engineering, University of...

  14. E-Print Network 3.0 - assisted pulsed laser Sample Search Results

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

    pulsed laser Search Powered by Explorit Topic List Advanced Search Sample search results for: assisted pulsed laser Page: << < 1 2 3 4 5 > >> 1 JOURNAL OF LIGHTWAVE TECHNOLOGY,...

  15. E-Print Network 3.0 - ankle pulse wave Sample Search Results

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

    Engineering 5 ARTICLE ARTICLE Functional electrical stimulation using Summary: is a train of stimulation pulses whose amplitude, pulse width, and rate are set to provide...

  16. E-Print Network 3.0 - adiabatic-rectangular pulse train Sample...

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

    rectangular pulse train Search Powered by Explorit Topic List Advanced Search Sample search results for: adiabatic-rectangular pulse train Page: << < 1 2 3 4 5 > >> 1 IEEE...

  17. E-Print Network 3.0 - attosecond pulse trains Sample Search Results

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

    Trains In HHG... polarized. Therefore, attosecond pulses generally are produced in a train, with two pulses ... Source: Kling, Matthias - Max-Planck-Institut fr Quantenoptik...

  18. E-Print Network 3.0 - analyzers pulse Sample Search Results

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

    From Dropout Summary: studied indirectly by performing measurements on the whole pulse train using an RF spectrum analyzer... in the pulse train was observed in the sampling...

  19. E-Print Network 3.0 - attosecond laser pulses Sample Search Results

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

    41 (2008) 081003 (5pp) doi:10.10880953-4075418081003 Summary: . Besides that, trains of attosecond pulses with only one pulse per infrared laser cycle can be produced......

  20. Reversing-counterpulse repetitive-pulse inductive storage circuit

    DOE Patents [OSTI]

    Honig, E.M.

    1984-06-05T23:59:59.000Z

    A high power reversing-counterpulse repetitive-pulse inductive storage and transfer circuit includes an opening switch, a main energy storage coil, a counterpulse capacitor and a small inductor. After counterpulsing the opening switch off, the counterpulse capacitor is recharged by the main energy storage coil before the load pulse is initiated. This gives the counterpulse capacitor sufficient energy for the next counterpulse operation, although the polarity of the capacitor's voltage must be reversed before that can occur. By using a current-zero switch as the counterpulse start switch, the capacitor is disconnected from the circuit (with a full charge) when the load pulse is initiated, preventing the capacitor from depleting its energy store by discharging through the load. After the load pulse is terminated by reclosing the main opening switch, the polarity of the counterpulse capacitor voltage is reversed by discharging the capacitor through a small inductor and interrupting the discharge current oscillation at zero current and peak reversed voltage. The circuit enables high-power, high-repetition-rate operation with reusable switches and features total control (pulse-to-pulse) over output pulse initiation, duration, repetition rate, and, to some extent, risetime.

  1. Capacitor charging FET switcher with controller to adjust pulse width

    DOE Patents [OSTI]

    Mihalka, Alex M. (Livermore, CA)

    1986-01-01T23:59:59.000Z

    A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20-50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the DC input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformer failure, or failure of the drive circuitry.

  2. Calendar Year study term 1

    E-Print Network [OSTI]

    Dawson, Jeff W.

    planet is in need of clean and renewable sources of energy such as wind, solar, geothermal, tidal and Renewable Energy Sources Electrical Power Engineering Study Term 6 Probability and Statistics Systems and biomass. Carleton University's program in Sustainable and Renewable Energy Engineering provides you

  3. Method and apparatus for analog pulse pile-up rejection

    DOE Patents [OSTI]

    De Geronimo, Gianluigi

    2014-11-18T23:59:59.000Z

    A method and apparatus for pulse pile-up rejection are disclosed. The apparatus comprises a delay value application constituent configured to receive a threshold-crossing time value, and provide an adjustable value according to a delay value and the threshold-crossing time value; and a comparison constituent configured to receive a peak-occurrence time value and the adjustable value, compare the peak-occurrence time value with the adjustable value, indicate pulse acceptance if the peak-occurrence time value is less than or equal to the adjustable value, and indicate pulse rejection if the peak-occurrence time value is greater than the adjustable value.

  4. Method and apparatus for analog pulse pile-up rejection

    DOE Patents [OSTI]

    De Geronimo, Gianluigi

    2013-12-31T23:59:59.000Z

    A method and apparatus for pulse pile-up rejection are disclosed. The apparatus comprises a delay value application constituent configured to receive a threshold-crossing time value, and provide an adjustable value according to a delay value and the threshold-crossing time value; and a comparison constituent configured to receive a peak-occurrence time value and the adjustable value, compare the peak-occurrence time value with the adjustable value, indicate pulse acceptance if the peak-occurrence time value is less than or equal to the adjustable value, and indicate pulse rejection if the peak-occurrence time value is greater than the adjustable value.

  5. Wide-range monitor for pulsed x-ray sources

    SciTech Connect (OSTI)

    Kaifer, R.C.; Jenkins, T.E.; Straume, T.

    1981-10-12T23:59:59.000Z

    A monitoring instrument based on a high-pressure ionization chamber has been developed that measures average dose rates as low as 0.1 mR/h and responds linearly to short pulses at dose rates up to 1.2 x 10/sup 10/ R/h. Its sensitivity can be remotely changed by a factor of 10/sup 4/, to enable accurate measurement of both background radiation and very high intensities such as can be expected from accelerator beam-spills. The instrument's detector-electrometer pulse response was measured using a dose-calibrated field-emission accelerator having a 30-ns pulse width.

  6. Improving the resolution of chopper spectrometers at pulsed neutron sources

    SciTech Connect (OSTI)

    Carpenter, J.M. (Argonne National Lab., IL (USA)); Mildner, D.F.R. (National Bureau of Standards, Washington, DC (USA). Center for Analytical Chemistry)

    1990-01-01T23:59:59.000Z

    We examine the relationships between intensity and resolution in pulsed-source chopper spectrometers, including the effects of Soller collimation, narrower rotor slits and higher rotor speeds. The basis is a simplified description of a spectrometer, approximately optimizing the rotor pulse and lighthouse effects. the analysis includes a new treatment of the angular distribution transmitted through a system consisting of a coarse collimator and a Soller collimator. The results encourage the prospect for a reasonably easily accomplished, higher resolution, optional configuration of the pulsed source chopper spectrometers at IPNS. 6 refs., 5 figs.

  7. Optimized pulse sequences for suppressing unwanted transitions in quantum systems

    SciTech Connect (OSTI)

    Schroeder, C. A.; Agarwal, G. S. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St. Norman, Oklahoma 73019 (United States); Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

    2011-01-15T23:59:59.000Z

    We investigate the nature of the pulse sequence so that unwanted transitions in quantum systems can be inhibited optimally. For this purpose we show that the sequence of pulses proposed by Uhrig [Phys. Rev. Lett. 98, 100504 (2007)] in the context of inhibition of environmental dephasing effects is optimal. We derive exact results for inhibiting the transitions and confirm the results numerically. We posit a very significant improvement by usage of the Uhrig sequence over an equidistant sequence in decoupling a quantum system from unwanted transitions. The physics of inhibition is the destructive interference between transition amplitudes before and after each pulse.

  8. Spectrometric Analysis for Pulse Jet Mixer Testing

    SciTech Connect (OSTI)

    ZEIGLER, KRISTINE

    2004-07-12T23:59:59.000Z

    The Analytical Development Section (ADS) was tasked with providing support for a Hanford River Protection Program-Waste Treatment Program (RPP-WTP) project test involving absorption analysis for non-Newtonian pulse jet mixer testing for small scale (PJM) and prototype (CRV) tanks with sparging. Tanks filled with clay were mixed with various amounts of powdered dye as a tracer. The objective of the entire project was to determine the best mixing protocol (nozzle velocity, number of spargers used, total air flow, etc.) by determining the percent mixed volume through the use of an ultraviolet-visible (UV-Vis) spectrometer. The dye concentration within the sample could be correlated to the volume fraction mixed in the tank. Samples were received in vials, a series of dilutions were generated from the clay, allowed to equilibrate, then centrifuged and siphoned for the supernate liquid to analyze by absorption spectroscopy. Equilibration of the samples and thorough mixing of the samples were a continuous issue with dilution curves being difficult to obtain. Despite these technical issues, useful data was obtained for evaluation of various mix conditions.

  9. The pulsed amplitude unit for the SLC

    SciTech Connect (OSTI)

    Rolfe, J.; Browne, M.J.; Jobe, R.K.

    1987-02-01T23:59:59.000Z

    There is a recurring requirement in the SLC for the control of devices such as magnets, phase shifters, and attenuators on a beam-by-beam basis. The Pulsed Amplitude Unit (PAU) is a single width CAMAC module developed for this purpose. It provides digitally programmed analog output voltages on a beam-by-beam basis. Up to 32 preprogrammed values of output voltage are available from the single analog output of the module, and any of these values can be associated with any of the 256 possible SLC beam definitions. A 12-bit Analog-to-Digital Converter (ADC) digitizes an analog input signal at the appropriate beam time and stores it in a buffer memory. This feature is normally used to monitor the response of the device being controlled by the PAU at each beam time. Initial application of the PAU is a part of the system that controls the output of Klystrons in the SLC. The PAU combines several different functions in a single module. In order to accommodate these functions in a single width CAMAC module, field programmed logic is used extensively. Field Programmable Logic Arrays, Programmed Array Logic, and a Field Programmable Logic Sequencer are employed.

  10. Zero Net Energy Myths and Modes of Thought

    E-Print Network [OSTI]

    Rajkovich, Nicholas B.

    2010-01-01T23:59:59.000Z

    mypp.html. ———. (2009). "Net-Zero Energy CommercialZero Net Energy Myths and Modes of Thought  Nicholas B.  AC02? 05CH11231. Page | i Zero Net Energy Myths and Modes of

  11. Acoustic modes in combustors with complex impedances and multidimensional active

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Acoustic modes in combustors with complex impedances and multidimensional active flames F. Nicoud-acoustic modes in combustors. In the case of a non-isothermal reacting medium, the wave equation for the pressure

  12. acoustic mode frequencies: Topics by E-print Network

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

    simulations were then compared to the number of p-modes candidates observed in real Sun-as-a-star data at low frequencies. The fraction of simulated spectra in which modes...

  13. Diagnostic for two-mode variable valve activation device

    DOE Patents [OSTI]

    Fedewa, Andrew M

    2014-01-07T23:59:59.000Z

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  14. Extracting Operating Modes from Building Electrical Load Data: Preprint

    SciTech Connect (OSTI)

    Frank, S.; Polese, L. G.; Rader, E.; Sheppy, M.; Smith, J.

    2012-01-01T23:59:59.000Z

    Empirical techniques for characterizing electrical energy use now play a key role in reducing electricity consumption, particularly miscellaneous electrical loads, in buildings. Identifying device operating modes (mode extraction) creates a better understanding of both device and system behaviors. Using clustering to extract operating modes from electrical load data can provide valuable insights into device behavior and identify opportunities for energy savings. We present a fast and effective heuristic clustering method to identify and extract operating modes in electrical load data.

  15. Viscoelastic modes in a strongly coupled, cold, magnetized dusty plasma

    SciTech Connect (OSTI)

    Banerjee, Debabrata; Mylavarapu, Janaki Sita; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, I/AF Bidhannagar, Calcutta 700 064 (India)

    2010-11-15T23:59:59.000Z

    A generalized hydrodynamical model has been used to study the low frequency modes in a strongly coupled, cold, magnetized dusty plasma. Such plasmas exhibit elastic properties due to the strong correlations among dust particles and the tensile stresses imparted by the magnetic field. It has been shown that longitudinal compressional Alfven modes and elasticity modified transverse shear mode exist in such a medium. The features of these collective modes are established and discussed.

  16. Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

    SciTech Connect (OSTI)

    Afhami, Saeedeh; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of)

    2014-06-15T23:59:59.000Z

    An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

  17. The Influence of Topology Changes on Inter-area Oscillation Modes and Mode Shapes

    SciTech Connect (OSTI)

    Chen, Yousu; Fuller, Jason C.; Diao, Ruisheng; Zhou, Ning; Huang, Zhenyu; Tuffner, Francis K.

    2011-10-17T23:59:59.000Z

    The topology of a power grid network is a piece of critical information for power grid operations. Different power grid topologies can change grid characteristics, inter-area oscillation modes, mode shapes, and even the robustness of the power system. This paper presents some preliminary study results, based on an approved WECC operating case and a modified low damping WECC system, to show the impact of topology changes resulting from N-1 contingencies on power system modes and mode shapes. The results show that topology changes can have very different impact on modal properties in a power system: some result in unstable situation, while others can improve small signal stability. For the former, the studies show about 4.5% damping reduction, so 5% damping margin would be required to ensure the system can sustain the contingencies. For the latter, those topology changes could be used as a control method to improve small signal stability. Mode shapes normally do not change when there is an N-1 topology change. These observations suggest that the inclusion of topological information is useful for improving the accuracy and effectiveness of power system control schemes.

  18. Transportation Mode Detection using Mobile Phones and GIS Information

    E-Print Network [OSTI]

    Wolfson, Ouri E.

    Transportation Mode Detection using Mobile Phones and GIS Information Leon Stenneth, Ouri Wolfson, Chicago, IL 60607-7053 {lstennet, wolfson, psyu, boxu} @cs.uic.edu ABSTRACT The transportation mode. In this paper, we propose an approach to inferring a user's mode of transportation based on the GPS sensor

  19. Stability Properties of Toroidal Alfvn Modes Driven by Fast Particles

    E-Print Network [OSTI]

    of a strong drive, TAEs will be strongly modi#28;ed to new types of mode, the Resonant TAE[8] or Energetic #12; which is able to resolve new resonant branches of the toroidal Alfvén modes called resonant TAE, such as DIII-D at General Atomics [3]. A new type of chirping frequency modes was re- ported in spherical

  20. Observation of pedestal turbulence in edge localized mode-free H-mode on experimental advanced superconducting tokamak

    SciTech Connect (OSTI)

    Han, X., E-mail: hanx@ipp.ac.cn; Zhang, T.; Zhang, S. B.; Wang, Y. M.; Shi, T. H.; Liu, Z. X.; Kong, D. F.; Qu, H.; Gao, X. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-10-15T23:59:59.000Z

    Two different pedestal turbulence structures have been observed in edge localized mode-free phase of H-mode heated by lower hybrid wave and RF wave in ion cyclotron range of frequencies (ICRF) on experimental advanced superconducting tokamak. When the fraction of ICRF power P{sub ICRF}/P{sub total} exceeds 0.7, coherent mode is observed. The mode is identified as an electromagnetic mode, rotating in electron diamagnetic direction with a frequency around 50 kHz and toroidal mode number n?=??3. Whereas when P{sub ICRF}/P{sub total} is less than 0.7, harmonic mode with frequency f?=?40–300 kHz appears instead. The characteristics of these two modes are demonstrated preliminarily. The threshold value of heating power and also the plasma parameters are distinct.