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1

Electronic High-Intensity Discharge Lighting  

Science Conference Proceedings (OSTI)

This EPRI Technical Update addresses the most promising controllable energy efficient light source electronic high-intensity discharge (HID) lighting. Business and technical market factors (Chapter 2) explain the upcoming growth of the HID lamp and electronic HID ballast market. Future technical improvements are emphasized along with discussion of the importance of utility involvement in helping their customers make the switch from magnetically-ballasted HID lighting to higher efficiency electronic HID l...

2007-12-21T23:59:59.000Z

2

ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.  

SciTech Connect

One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

WEI,J.; MACEK,R.J.

2002-04-14T23:59:59.000Z

3

A New High Intensity Electron Beam for Wakefield Acceleration...  

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

HIGH INTENSITY ELECTRON BEAM FOR WAKEFIELD ACCELERATION STUDIES* M.E. Conde , W. Gai, C. Jing, R. Konecny, W. Liu, J.G. Power, H. Wang, Z. Yusof ANL, Argonne, IL 60439, USA...

4

ELECTRON COUD DYNAMICS IN HIGH-INTENSITY RINGS.  

SciTech Connect

Electron cloud due to beam-induced multipacting is one of the main concerns for the high intensity. Electrons generated and accumulated inside the beam pipe form an ''electron cloud'' that interacts with the circulating charged particle beam. With sizeable amount of electrons, this interaction can cause beam instability, beam loss and emittance growth. At the same time, the vacuum pressure will rise due to electron desorption. This talk intends to provide an overview of the mechanism and dynamics of the typical electron multipacting in various magnetic fields and mitigation measures with different beams.

WANG, L.; WEI, J.

2005-05-16T23:59:59.000Z

5

Slow Electrons Generated by Intense High-Frequency Laser Pulses  

Science Conference Proceedings (OSTI)

A very slow electron is shown to emerge when an intense high-frequency laser pulse is applied to a hydrogen negative ion. This counterintuitive effect cannot be accounted for by multiphoton or tunneling ionization mechanisms. We explore the effect and show that in the high-frequency regime the atomic electron is promoted to the continuum via a nonadiabatic transition caused by slow deformation of the dressed potential that follows a variation of the envelope of the laser pulse. This is a general mechanism, and a slow electron peak should always appear in the photoelectron spectrum when an atom is irradiated by a high-frequency pulse of finite length.

Toyota, Koudai; Watanabe, Shinichi [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); Tolstikhin, Oleg I. [Russian Research Center 'Kurchatov Institute', Kurchatov Square 1, Moscow 123182 (Russian Federation); Morishita, Toru [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2009-10-09T23:59:59.000Z

6

400-Watt Electronic High-Bay Fixture for Metal-Halide High-Intensity Discharge Lighting  

Science Conference Proceedings (OSTI)

The product under assessment is an advanced lighting technology8212a 400-watt, metal-halide, electronic high-intensity discharge (HID) ballast technology designed to be operated as a stand-alone ballast or integrated as a fixture where the ballast becomes part of the fixture mechanical support system.

2008-06-12T23:59:59.000Z

7

Initial Results of the New High Intensity Electron Gun at the...  

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

INITIAL RESULTS OF THE NEW HIGH INTENSITY ELECTRON GUN AT THE ARGONNE WAKEFIELD ACCELERATOR * M.E. Conde, W. Gai, R. Konecny, J.G. Power, P. Schoessow, X. Sun, ANL, Argonne, IL...

8

Device for providing high-intensity ion or electron beam  

SciTech Connect

A thin film of a low-thermionic-work-function material is maintained on the cathode of a device for producing a high-current, low-pressure gas discharge by means of sputter deposition from an auxiliary electrode. The auxiliary electrode includes a surface with a low-work-function material, such as thorium, uranium, plutonium or one of the rare earth elements, facing the cathode but at a disposition and electrical potential so as to extract ions from the gas discharge and sputter the low-work-function material onto the cathode. By continuously replenishing the cathode film, high thermionic emissions and ion plasmas can be realized and maintained over extended operating periods.

McClanahan, Edwin D. (Richland, WA); Moss, Ronald W. (Richland, WA)

1977-01-01T23:59:59.000Z

9

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen targetr constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center (SLAC). The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, cosntruction details and operating experience are discussed.

Mark, J.W.

1984-02-01T23:59:59.000Z

10

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen target constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center. The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, construction details and operating experience are discussed.

Mark, J.W.

1983-07-01T23:59:59.000Z

11

Calculation of synchrotron radiation from high intensity electron beam at eRHIC  

Science Conference Proceedings (OSTI)

The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

Jing Y.; Chubar, O.; Litvinenko, V.

2012-05-20T23:59:59.000Z

12

High intensity electron beam ion trap for charge state boosting of radioactive ion beams  

SciTech Connect

A high intensity electron beam ion trap under development at LLNL could be adapted for charge state boosting of radioactive ion beams, enabling a substantial reduction in the size and cost of a post-accelerator. We report estimates of the acceptance, ionization time, charge state distribution, emittance, and beam intensity for charge state boosting of radioactive ions in this device. The estimates imply that, for tin isotopes, over 10{sup 10} ions/s can be ionized to q = 40+ with an absolute emittance of approximately 1 (pi) mm mrad at an energy of 30 x q.k.

Marrs, R.

1998-09-30T23:59:59.000Z

13

High intensity hadron accelerators  

SciTech Connect

This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

Teng, L.C.

1989-05-01T23:59:59.000Z

14

Assessment of Electrical, Efficiency, and Photometric Performance of Advanced Lighting Sources: Dimmable Advanced Lighting Technolog ies -- Electronic High-Intensity Discharge Ballasts  

Science Conference Proceedings (OSTI)

This EPRI Technical Update addresses the dimming performance of electronic high-intensity discharge (HID) ballasts. Chapter 1 provides a discussion of basic lighting control, the importance of considering power quality in lighting control, lighting control methods and parameters, and the advantages and future of lighting control. Chapter 2 addresses in more depth the dimming methods used in advanced lighting sources and controls for incandescent, fluorescent, high-intensity discharge (HID) and light-emit...

2008-12-18T23:59:59.000Z

15

Harmonic generation at high intensities  

Science Conference Proceedings (OSTI)

Atomic electrons subject to intense laser fields can absorb many photons, leading either to multiphoton ionization or the emission of a single, energetic photon which can be a high multiple of the laser frequency. The latter process, high-order harmonic generation, has been observed experimentally using a range of laser wavelengths and intensities over the past several years. Harmonic generation spectra have a generic form: a steep decline for the low order harmonics, followed by a plateau extending to high harmonic order, and finally an abrupt cutoff beyond which no harmonics are discernible. During the plateau the harmonic production is a very weak function of the process order. Harmonic generation is a promising source of coherent, tunable radiation in the XUV to soft X-ray range which could have a variety of scientific and possibly technological applications. Its conversion from an interesting multiphoton phenomenon to a useful laboratory radiation source requires a complete understanding of both its microscopic and macroscopic aspects. We present some recent results on the response of single atoms at intensities relevant to the short pulse experiments. The calculations employ time-dependent methods, which we briefly review in the next section. Following that we discuss the behavior of the harmonics as a function of laser intensity. Two features are notable: the slow scaling of the harmonic intensities with laser intensity, and the rapid variation in the phase of the individual harmonics with respect to harmonic order. We then give a simple empirical formula that predicts the extent of the plateau for a given ionization potential, wavelength and intensity.

Schafer, K.J.; Krause, J.L.; Kulander, K.C.

1993-06-01T23:59:59.000Z

16

Transverse instability in high intensity proton rings  

SciTech Connect

In recent years, many applications are being considered for low energy high intensity proton synchrotrons. Most high intensity proton rings are at low energy below transition. Several aspects of the beam dynamics of this kind of rings are different from the electron or high energy rings. The transverse microwave instabilities will be discussed in this article.

Zhang, S.Y.; Weng, W.T.

1997-07-01T23:59:59.000Z

17

Polarisation response of a gas medium in the field of a high-intensity ultrashort laser pulse: high order Kerr nonlinearities or plasma electron component?  

SciTech Connect

The polarisation response of quantum systems modelling silver and xenon atoms in the field of a high-intensity femtosecond Ti : sapphire laser (photon energy h{omega} Almost-Equal-To 1.5 eV), has been investigated by direct numerical integration of the Schroedinger equation. The applicability ranges of the perturbation theory and polarisation expansion in powers of field are determined. The contributions of excited atoms and electrons in the continuous-spectrum states to the polarisation response at the fundamental frequency, which arise as a result of excitation and photoionisation, are analysed. It is shown that specifically ionisation changes the sign of dielectric susceptibility with an increase in radiation intensity for the systems under consideration. (interaction of laser radiation with matter. laser plasmas)

Volkova, E A; Popov, Alexander M; Tikhonova, O V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2012-08-31T23:59:59.000Z

18

Assessment of Electrical, Efficiency, and Photometric Performance of Advanced Lighting Technologies: Dimmable Advanced Lighting Tech nologies -- Electronic Fluorescent, High-Intensity Discharge, and Light-Emitting Diode  

Science Conference Proceedings (OSTI)

This EPRI Technical Report is a compilation of four technical updates that address the basic dimming performance of advanced lighting sources: EPRI report 1018476 for linear fluorescent ballasts, 1018477 for hot and cold cathode compact fluorescent lamps, 1018479 for electronic high-intensity discharge (HID) ballasts, and 1018480 for light-emitting diode (LED) lighting. Chapter 1 provides a discussion of basic lighting control, the importance of considering power quality in lighting control, lighting con...

2008-12-22T23:59:59.000Z

19

X-ray polarization spectroscopy to study anisotropic velocity distribution of hot electrons produced by an ultra-high-intensity laser  

SciTech Connect

The anisotropy of the hot-electron velocity distribution in ultra-high-intensity laser produced plasma was studied with x-ray polarization spectroscopy using multilayer planar targets including x-ray emission tracer in the middle layer. This measurement serves as a diagnostic for hot-electron transport from the laser-plasma interaction region to the overdense region where drastic changes in the isotropy of the electron velocity distribution are observed. These polarization degrees are consistent with analysis of a three-dimensional polarization spectroscopy model coupled with particle-in-cell simulations. Electron velocity distribution in the underdense region is affected by the electric field of the laser and that in the overdense region becomes wider with increase in the tracer depth. A full-angular spread in the overdense region of 22.4 deg.{sub -2.4}{sup +5.4} was obtained from the measured polarization degree.

Inubushi, Y. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Graduate School of Engineering, Osaka University, Suita, Osaka (Japan); Okano, Y.; Nishimura, H.; Cai, H.; Nagatomo, H.; Kai, T.; Fujioka, S.; Nakamura, T.; Johzaki, T.; Mima, K. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Kawamura, T. [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Batani, D.; Morace, A.; Redaelli, R. [Dipartmento di Fisica 'G. Occhialini', University of Milano-Bicocca, Milan (Italy); Fourment, C.; Santos, J. J.; Malka, G. [CELIA, Universite de Bordeaux/CNRS/CEA, Talence (France); Boscheron, A.; Bonville, O.; Grenier, J. [CEA/CESTA, Le Barp (France)

2010-03-15T23:59:59.000Z

20

High intensity protons in RHIC  

SciTech Connect

During the 2012 summer shutdown a pair of electron lenses will be installed in RHIC, allowing the beam-beam parameter to be increased by roughly 50 percent. To realize the corresponding luminosity increase bunch intensities have to be increased by 50 percent, to 2.5 {center_dot} 10{sup 11} protons per bunch. We list the various RHIC subsystems that are most affected by this increase, and propose beam studies to ensure their readiness. The proton luminosity in RHIC is presently limited by the beam-beam effect. To overcome this limitation, electron lenses will be installed in IR10. With the help of these devices, the headon beam-beam kick experienced during proton-proton collisions will be partially compensated, allowing for a larger beam-beam tuneshift at these collision points, and therefore increasing the luminosity. This will be accomplished by increasing the proton bunch intensity from the presently achieved 1.65 {center_dot} 10{sup 11} protons per bunch in 109 bunches per beam to 2.5 {center_dot} 10{sup 11}, thus roughly doubling the luminosity. In a further upgrade we aim for bunch intensities up to 3 {center_dot} 10{sup 11} protons per bunch. With RHIC originally being designed for a bunch intensity of 1 {center_dot} 10{sup 11} protons per bunch in 56 bunches, this six-fold increase in the total beam intensity by far exceeds the design parameters of the machine, and therefore potentially of its subsystems. In this note, we present a list of major subsystems that are of potential concern regarding this intensity upgrade, show their demonstrated performance at present intensities, and propose measures and beam experiments to study their readiness for the projected future intensities.

Montag, C.; Ahrens& #44; L.; Blaskiewicz& #44; M.; Brennan& #44; J.M.; Drees& #44; K.A.; Fischer& #44; W.; Huang& #44; H.; Minty& #44; M.; Robert-Demolaize& #44; G.; Thieberger& #44; P.; Yip& #44; K.

2012-01-05T23:59:59.000Z

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


21

High-Intensity Discharge Lighting  

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

High-intensity discharge (HID) lighting provides the highest efficacy and longest service life of any lighting type. It can save 75%-90% of lighting energy when it replaces incandescent lighting.

22

Operation of a large GEM-MSGC detector in a high intensity hadronic test beam using fully pipelined readout electronics  

E-Print Network (OSTI)

98-060 In a recent test beam experiment at PSI a new tracking device for very high particle fluxes consisting of a low gain micro strip gas chamber (MSGC) combined with a gas electron multiplier (GEM) foil has been run under beam conditions similar to those foreseen in the HERA-B experiment [1], where such devices are being installed for the inner tracker. They are also being evaluated for the LHCb experiment [2]. In both detectors very high, mainly hadronic particle densities (up to 10 4 mm -2 sec -1) are expected, while the momentum resolution of the magnetic spectrometers foreseen in the two experiments is limited by multiple scattering. Also photon conversions represent a significant background source and therefore a minimal thickness in terms of radiation length is important, while position resolution requirements are moderate (typically 300 mu m pitch is sufficient). This paper describes the detailed construction of this novel detector, the test beam configuration and some of the data taken using the fu...

Eisele, F; Straumann, U; Straumann, Ulrich

1998-01-01T23:59:59.000Z

23

Intense steady state electron beam generator  

DOE Patents (OSTI)

An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source. 2 figs.

Hershcovitch, A.; Kovarik, V.J.; Prelec, K.

1990-07-17T23:59:59.000Z

24

Short rise time intense electron beam generator  

DOE Patents (OSTI)

A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

Olson, Craig L. (Albuquerque, NM)

1987-01-01T23:59:59.000Z

25

Optimizing electron-positron pair production on kilojoule-class high-intensity lasers for the purpose of pair-plasma creation  

Science Conference Proceedings (OSTI)

Expressions for the yield of electron-positron pairs, their energy spectra, and production rates have been obtained in the interaction of multi-kJ pulses of high-intensity laser light interacting with solid targets. The Bethe-Heitler conversion of hard x-ray bremsstrahlung [D. A. Gryaznykh, Y. Z. Kandiev, and V. A. Lykov, JETP Lett. 67, 257 (1998); K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505 (2002)] is shown to dominate over direct production (trident process) [E. P. Liang, S. C. Wilks, and M. Tabak, Phys. Rev. Lett. 81, 4887 (1998)]. The yields and production rates have been optimized as a function of incident laser intensity by the choice of target material and dimensions, indicating that up to 5x10{sup 11} pairs can be produced on the OMEGA EP laser system [L. J. Waxer et al., Opt. Photonics News 16, 30 (2005)]. The corresponding production rates are high enough to make possible the creation of a pair plasma.

Myatt, J.; Delettrez, J. A.; Maximov, A. V.; Meyerhofer, D. D.; Short, R. W.; Stoeckl, C.; Storm, M. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2009-06-15T23:59:59.000Z

26

Effect of the change in the load resistance on the high voltage pulse transformer of the intense electron-beam accelerators  

Science Conference Proceedings (OSTI)

A high voltage pulse transformer (HVPT) is usually used as a charging device for the pulse forming line (PFL) of intense electron-beam accelerators (IEBAs). Insulation of the HVPT is one of the important factors that restrict the development of the HVPT. Until now, considerable effort has been focused on minimizing high field regions to avoid insulation breakdown between windings. Characteristics of the HVPT have been widely discussed to achieve these goals, but the effects of the PFL and load resistance on HVPT are usually neglected. In this paper, a HVPT is used as a charging device for the PFL of an IEBA and the effect of the change in the load resistance on the HVPT of the IEBA is presented. When the load resistance does not match the wave impedance of the PFL, a high-frequency bipolar oscillating voltage will occur, and the amplitude of the oscillating voltage will increase with the decrease in the load resistance. The load resistance approximates to zero and the amplitude of the oscillating voltage is much higher. This makes it easier for surface flashover along the insulation materials to form and decrease the lifetime of the HVPT.

Cheng Xinbing; Liu Jinliang; Qian Baoliang; Zhang Yu; Zhang Hongbo [College of Photoelectrical Science and Engineering, National University of Defense Technology, Hunan 410073 (China)

2009-11-15T23:59:59.000Z

27

Ionized channel generation of an intense-relativistic electron beam  

DOE Patents (OSTI)

A foilless intense relativistic electron beam generator uses an ionized cnel to guide electrons from a cathode passed an anode to a remote location.

Frost, Charles A. (Albuquerque, NM); Leifeste, Gordon T. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

28

High Speed Electronics  

Science Conference Proceedings (OSTI)

High Speed Electronics. ... optic sampling system provides traceability for our electrical waveform measurements ... Metrology for Electronic Packaging. ...

2013-03-25T23:59:59.000Z

29

Photoionization of hydrogen atom by coherent intense high-frequency short laser pulses: Direct propagation of electron wave packets on enormous spatial grids  

E-Print Network (OSTI)

The time-dependent Schr\\"{o}dinger equation for the hydrogen atom and its interaction with coherent intense high-frequency short laser pulses is solved numerically exactly by employing the code implemented for the multi-configurational time-dependent Hartree-Fock (MCTDHF) method. Thereby, the wavefunction is followed in space and time for times longer than the pulse duration. Results are explicitly shown for 3 and 10 fs pulses. Particular attention is paid to identifying the effect of dynamic interference of photoelectrons emitted with the same kinetic energy at different times during the rising and falling sides of the pulse predicted in [\\emph{Ph.V. Demekhin and L.S. Cederbaum}, Phys. Rev. Lett. \\textbf{108}, 253001 (2012)]. In order to be able to see the dynamic interference pattern in the computed electron spectra, the photoelectron wave packet has to be propagated over long distances. Clearly, complex absorption potentials often employed to compute spectra of emitted particles cannot be used to detect dy...

Demekhin, Philipp V; Cederbaum, Lorenz S

2013-01-01T23:59:59.000Z

30

High-Intensity Proton Accelerator  

SciTech Connect

Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

Jay L. Hirshfield

2011-12-27T23:59:59.000Z

31

STABILIZED HIGH INTENSITY SOURCE OF 80 kv  

SciTech Connect

With the change of the current load from 0 to 2.5 mamp and simultaneous change of incoming intensity from 270 to 190 v, the stabilized high-intensity source changes less than l%.. The stabilized intensity can be arranged in steps of 5 kv from 60 to 80 kv. The high-intensity stabilizer automatically switches on upon reaching 60 kv. (tr-auth)

Polivanov, V.V.; Izyurov, A.V.; Pyatakov, N.I.

1959-09-01T23:59:59.000Z

32

Intense synchrotron radiation from a magnetically compressed relativistic electron layer  

SciTech Connect

Using a simple model of a relativistic electron layer rotating in an axial magnetic field, energy gain by an increasing magnetic field and energy loss by synchrotron radiation were considered. For a typical example, initial conditions were approximately 8 MeV electron in approximately 14 kG magnetic field, at a layer radius of approximately 20 mm, and final conditions were approximately 4 MG magnetic field approximately 100 MeV electron layer energy at a layer radius of approximately 1.0 mm. In the final state, the intense 1-10 keV synchrotron radiation imposes an electron energy loss time constant of approximately 100 nanoseconds. In order to achieve these conditions in practice, the magnetic field must be compressed by an imploding conducting liner; preferably two flying rings in order to allow the synchrotron radiation to escape through the midplane. The synchrotron radiation loss rate imposes a lower limit to the liner implosion velocity required to achieve a given final electron energy (approximately 1 cm/$mu$sec in the above example). In addition, if the electron ring can be made sufficiently strong (field reversed), the synchrotron radiation would be a unique source of high intensity soft x-radiation. (auth)

Shearer, J.W.; Nowak, D.A.; Garelis, E.; Condit, W.C.

1975-10-01T23:59:59.000Z

33

Ionized channel generation of an intense relativistic electron beam  

DOE Patents (OSTI)

An intense relativistic electron beam generator uses an ionized channel to guide electrons from a cathode past an anode to a remote location without the use of a foil.

Frost, C.A.; Leifeste, G.T.; Shope, S.L.

1986-03-31T23:59:59.000Z

34

High intensity performance of the Brookhaven AGS  

SciTech Connect

Experience and results from recent high intensity proton running periods of the Brookhaven AGS, during which a record intensity for a proton synchrotron of 6.3 x 10{sup 13} protons/pulse was reached, is presented. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.

Brennan, J.M.; Roser, T.

1996-07-01T23:59:59.000Z

35

High brightness electron accelerator  

DOE Patents (OSTI)

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity.

Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

1992-12-31T23:59:59.000Z

36

Nonlinear Magnetoresistance Oscillations in Intensely Irradiated Two-Dimensional Electron Systems Induced by Multiphoton Processes.  

SciTech Connect

We report on magneto-oscillations in differential resistivity of a two-dimensional electron system subject to intense microwave radiation. The period of these oscillations is determined not only by microwave frequency but also by its intensity. A theoretical model based on quantum kinetics at high microwave power captures all important characteristics of this phenomenon which is strongly nonlinear in microwave intensity. Our results demonstrate a crucial role of the multiphoton processes near the cyclotron resonance and its harmonics in the presence of strong dc electric field and offer a unique way to reliably determine the intensity of microwaves acting on electrons.

Khodas, M.; Chiang, H.-S.; Hatke, A.T.; Zudov, M.A.; Vavilov, M.G.; Pfeiffer, L.N.; West, K.W.

2010-05-21T23:59:59.000Z

37

HIGH INTENSITY PERFORMANCE OF THE BROOKHAVEN AGS.  

SciTech Connect

The Brookhaven AGS provides 24 GeV protons for a multi-user program of fixed-target high energy physics experiments, such as the study of extremely rare Kaon decays. Up to 7 x 10{sup 13} protons are slowly extracted over 2.2 seconds each 5.1 seconds. The muon storage ring of the g-2 experiment is supplied with bunches of 7 x 10{sup 12} protons. Since the completion of the a 1.9 GeV Booster synchrotron and installation of a new high-power rf system and transition jump system in the AGS various modes of operation have been explored to overcome space charge limits and beam instabilities at these extreme beam intensities. Experiments have been done using barrier cavities to enable accumulation of debunched beam in the AGS as a potential path to significantly higher intensities. We report on the present understanding of intensity limitations and prospects for overcoming them.

AHRENS,L.A.; ALESSI,J.; BLASKIEWICZ,M.; BRENNAN,J.M.; BROWN,K.; GARDNER,C.; GLENN,J.W.; ROSER,T.; SMITH,K.S.; VAN ASSELT,W.; ZHANG,S.Y.

1999-03-29T23:59:59.000Z

38

AGS RESONANT EXTRACTION WITH HIGH INTENSITY BEAMS.  

SciTech Connect

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams.[1] Learning to extract and transport these higher intensity beams has required a process of careful modeling and experimentation. We have had to learn how to correct for various instabilities and how to better match extraction and the transport lines to the higher emittance beams being accelerated in the AGS. Techniques employed include ''RF'' methods to smooth out momentum distributions and fine structure. We will present results of detailed multi-particle tracking modeling studies which enabled us to develop a clear understanding of beam loss mechanisms in the transport and extraction process. We will report on our status, experiences, and the present understanding of the intensity limitations imposed by resonant extraction and transport to fixed target stations.

AHRENS,L.; BROWN,K.; GLENN,J.W.; ROSER,T.; TSOUPAS,N.; VANASSELT,W.

1999-03-29T23:59:59.000Z

39

Computational Simulations of High Intensity X-Ray Matter Interaction  

SciTech Connect

Free electron lasers have the promise of producing extremely high-intensity short pulses of coherent, monochromatic radiation in the 1-10 keV energy range. For example, the Linac Coherent Light Source at Stanford is being designed to produce an output intensity of 2 x 10{sup 14} W/cm{sup 2} in a 230 fs pulse. These sources will open the door to many novel research studies. However, the intense x-ray pulses may damage the optical components necessary for studying and controlling the output. At the full output intensity, the dose to optical components at normal incidence ranges from 1-10 eV/atom for low-Z materials (Z < 14) at photon energies of 1 keV. It is important to have an understanding of the effects of such high doses in order to specify the composition, placement, and orientation of optical components, such as mirrors and monochromators. Doses of 10 eV/atom are certainly unacceptable since they will lead to ablation of the surface of the optical components. However, it is not precisely known what the damage thresholds are for the materials being considered for optical components for x-ray free electron lasers. In this paper, we present analytic estimates and computational simulations of the effects of high-intensity x-ray pulses on materials. We outline guidelines for the maximum dose to various materials and discuss implications for the design of optical components.

London, R A; Rionta, R; Tatchyn, R; Roessler, S

2001-08-02T23:59:59.000Z

40

Very high intensity reaction chamber design  

SciTech Connect

The problem of achieving very high intensity irradiation by light in minimal regions was studied. Three types of irradiation chamber are suggested: the common laser-reaction chamber, the folded concentric or near-concentric resonator, and the asymmetric confocal resonator. In all designs the ratio of high-intensity illuminated volume to other volume is highly dependent (to the $sup 3$/$sub 2$ power) on the power and fluence tolerances of optical elements, primarily mirrors. Optimization of energy coupling is discussed for the common cavity. For the concentric cavities, optimization for both coherent and incoherent beams is treated. Formulae and numerical examples give the size of chambers, aspect ratios, maximum pass number, image sizes, fluences, and the like. Similarly for the asymmetric confocal chamber, formulae and numerical examples for fluences, dimensions, losses, and totally contained pass numbers are given. (auth)

Devaney, J.J.

1975-09-01T23:59:59.000Z

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


41

Resonant Auger Effect at High X-Ray Intensity  

SciTech Connect

The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

Rohringer, N; Santra, R

2008-03-27T23:59:59.000Z

42

High Availability Electronics Standards  

Science Conference Proceedings (OSTI)

Availability modeling of the proposed International Linear Collider (ILC) predicts unacceptably low uptime with current electronics systems designs. High Availability (HA) analysis is being used as a guideline for all major machine systems including sources, utilities, cryogenics, magnets, power supplies, instrumentation and controls. R&D teams are seeking to achieve total machine high availability with nominal impact on system cost. The focus of this paper is the investigation of commercial standard HA architectures and packaging for Accelerator Controls and Instrumentation. Application of HA design principles to power systems and detector instrumentation are also discussed.

Larsen, R.S.; /SLAC

2006-12-13T23:59:59.000Z

43

High intensity discharge device containing oxytrihalides  

DOE Patents (OSTI)

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO.sub.2, with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube.

Lapatovich, Walter P. (Hudson, MA); Keeffe, William M. (Rockport, MA); Liebermann, Richard W. (Danvers, MA); Maya, Jakob (Brookline, MA)

1987-01-01T23:59:59.000Z

44

High intensity discharge device containing oxytrihalides  

DOE Patents (OSTI)

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

1987-06-09T23:59:59.000Z

45

Energetic electron propagation in solid targets driven by the intense electric fields of femtosecond laser pulses  

Science Conference Proceedings (OSTI)

An analytical model is used to interpret experimental data on the propagation of energetic electrons perpendicular to and parallel to the propagation direction of intense femtosecond laser pulses that are incident on solid targets. The pulses with {approx_equal}10{sup 20} W/cm{sup 2} intensity are incident normal onto a gadolinium or tungsten wire embedded in an aluminum substrate, and MeV electrons generated in the focal spot propagate along the laser direction into the irradiated wire. Electrons also propagate laterally from the focal spot through the aluminum substrate and into a dysprosium or hafnium spectator wire at a distance up to 1 mm from the irradiated wire. The ratio of the K shell emission from the spectator and irradiated wires is a measure of the numbers and energies of the MeV electrons propagating parallel to and perpendicular to the intense oscillating electric field of the laser pulse. It is found that the angular distribution of electrons from the focal spot is highly non-isotropic, and approximately twice as many electrons are driven by the electric field toward the spectator wire as into the irradiated wire. This quantitative result is consistent with the qualitative experimental observation that the oscillating electric field of an intense femtosecond laser pulse, when interacting with a heavy metal target, preferentially drives energetic electrons in the electric field direction as compared to perpendicular to the field.

Seely, J. F. [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Szabo, C. I. [Artep, Inc., 2922 Excelsior Spring Circle, Ellicott City, Maryland 21042 (United States); Audebert, P.; Brambrink, E. [Laboratoire pour L'Utilisation des Lasers Intenses (LULI), Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2011-06-15T23:59:59.000Z

46

ENERGY DISTRIBUTION OF TWO-ELECTRON IONIZATION OF HELIUM IN AN INTENSE LASER FIELD.  

DOE Green Energy (OSTI)

It is well known that a neutral atom interacting with a strong laser field will ionize at sufficiently high intensity even for photon energies well below the ionization threshold. When the required number of photons becomes very large, this process is best described by the suppression of the Coulomb barrier by the laser's oscillating electric field, allowing the electron to tunnel into the continuum. As the laser intensity is increased, more tightly bound electrons may be successively liberated by this mechanism. Such a sequential multiple ionization, long accepted as a reasonable approach to the formidable problem of a multielectron atom interacting nonperturbatively with an intense electromagnetic field, provides fair estimates of the various charge state appearance intensities while the tunneling rates are in excellent agreement with single ionization yields. However, more accurate measurements revealed systematic and very large deviations from the tunneling rates: near appearance intensity under standard experimental conditions, the observed double ion yield is several orders of magnitude larger than predicted by the sequential rate. It soon became clear that electrons could not be considered as independent and that electron-electron correlation had to be taken into account. Dynamic correlations have been considered in several theories. First qualitatively in the shakeoff model; then empirically through the e-2e cross-section in the quantum/classical three-step model (tunnel ionization, acceleration by the oscillating electric field and e-2e recollision with the ion); recently through the so-called intense field many-body-S-matrix theory and a purely empirical model of collective tunnel ionization. The validity of these ideas has been examined using numerical models. The measurement of total ion yields over a dynamic range exceeding ten orders of magnitude, a major breakthrough made possible by the availability of high-repetition rate lasers at the beginning of the 90's, was for a long time the only quantitative data to confront theory.

LAFON,R.; CHALOUPKA,J.L.; SHEEHY,B.; DIMAURO,L.F.; PAUL,P.M.; AGOSTINI,P.; KULANDER,K.C.

2000-09-24T23:59:59.000Z

47

High-Intensity Discharge Lighting Basics | Department of Energy  

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

High-Intensity Discharge Lighting Basics High-Intensity Discharge Lighting Basics High-Intensity Discharge Lighting Basics August 15, 2013 - 5:59pm Addthis High-intensity discharge (HID) lighting provides the highest efficacy and longest service life of any lighting type. It can save 75%-90% of lighting energy when it replaces incandescent lighting. Illustration of a high-intensity discharge (HID) lIllustration amp. The lamp is a tall cylindrical shape, and a cutout of the outer tube shows the materials inside. A long, thin cylinder called the arc tube runs through the lamp between two electrodes. The space around the arc tube is labeled as a vacuum. In a high-intensity discharge lamp, electricity arcs between two electrodes, creating an intensely bright light. Mercury, sodium, or metal halide gas

48

HIGH INTENSITY BEAM OPERATION OF THE BROOKHAVEN AGS  

SciTech Connect

For the last few years the Brookhaven AGS has operated at record proton intensities. This high beam intensity allowed for the simultaneous operation of several high precision rare kaon decay experiments. The record beam intensities were achieved after the AGS Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. The intensity is presently limited by space charge effects at both Booster and AGS injection and transverse instabilities in the AGS.

ROSER,T.

1999-06-28T23:59:59.000Z

49

Beam experiments towards high-intensity beams in RHIC  

SciTech Connect

Proton bunch intensities in RHIC are planned to be increased from 2 {center_dot} 10{sup 11} to 3 {center_dot} 10{sup 11} protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results are presented.

Montag C.; Ahrens, L.; Brennan, J.M.; Blaskiewicz, M.; Drees, A.; Fischer, W.; Hayes, T.; Huang, H.; Mernick, K.; Robert-Demolaize, G.; Smith, K.; Than, R.; Thieberger, P.; Yip, K.; Zeno, K.; Zhang, S.Y.

2012-05-20T23:59:59.000Z

50

Performances of BNL high-intensity synchrotrons  

SciTech Connect

The AGS proton synchrotron was completed in 1960 with initial intensity in the 10 to the 10th power proton per pulse (ppp) range. Over the years, through many upgrades and improvements, the AGS now reached an intensity record of 6.3 {times} 10{sup 13} ppp, the highest world intensity record for a proton synchrotron on a single pulse basis. At the same time, the Booster reached 2.2 {times} 10{sup 13} ppp surpassing the design goal of 1.5 {times} 10{sup 13} ppp due to the introduction of second harmonic cavity during injection. The intensity limitation caused by space charge tune spread and its relationship to injection energy at 50 MeV, 200 MeV, and 1,500 MeV will be presented as well as many critical accelerator manipulations. BNL currently participates in the design of an accumulator ring for the SNS project at Oak Ridge. The status on the issues of halo formation, beam losses and collimation are also presented.

Weng, W.T.

1998-03-01T23:59:59.000Z

51

High pressure study of changes in energy and intensity of excitations in crystalline metal glyoximes  

SciTech Connect

The effect of high pressure has been measured on the energy and integrated intensity of electronic excitations of several layered crystals of glyoximes containing Ni, Pd, or Pt. Large changes in both energy and intensity were observed, both of which were completely reversible. The shifts in energy with pressure, are explained in terms of the relative spatial extent of the outer d and p orbitals of Ni, Pd, and Pt. The effects of back donation from the ligands and intensity borrowing from the higher energy charge transfer excitations are considered as possible causes of the observed intensity changes. It was concluded that intensity borrowing was the major cause of the observed changes.

Tkacz, M.; Drickamer, H.G.

1986-07-15T23:59:59.000Z

52

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons  

Science Conference Proceedings (OSTI)

We present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 micrometers and mass of a few 10{sup -8} g were irradiated with up to 7 J of laser energy focused to intensities of several 10{sup 19} W/cm{sup 2}. The conversion of laser energy to K-alpha radiation is measured, as well as high resolution spectra that allow observation of line shifts, indicating isochoric heating of the target up to 18 eV. A zero-dimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.

Neumayer, P; Lee, H J; Offerman, D; Shipton, E; Kemp, A; Kritcher, A L; Doppner, T; Back, C A; Glenzer, S H

2009-02-04T23:59:59.000Z

53

High intensity performance and upgrades at the Brookhaven AGS  

SciTech Connect

For the last two years the Brookhaven AGS has operated the slow extracted beam program at record proton intensities. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.

Roser, T.

1996-12-31T23:59:59.000Z

54

High-order harmonics from bow wave caustics driven by a high-intensity laser  

Science Conference Proceedings (OSTI)

We propose a new mechanism of high-order harmonic generation during an interaction of a high-intensity laser pulse with underdense plasma. A tightly focused laser pulse creates a cavity in plasma pushing electrons aside and exciting the wake wave and the bow wave. At the joint of the cavity wall and the bow wave boundary, an annular spike of electron density is formed. This spike surrounds the cavity and moves together with the laser pulse. Collective motion of electrons in the spike driven by the laser field generates high-order harmonics. A strong localization of the electron spike, its robustness to oscillations imposed by the laser field and, consequently, its ability to produce high-order harmonics is explained by catastrophe theory. The proposed mechanism explains the experimental observations of high-order harmonics with the 9 TW J-KAREN laser (JAEA, Japan) and the 120 TW Astra Gemini laser (CLF RAL, UK) [A. S. Pirozhkov, et al., arXiv:1004.4514 (2010); A. S. Pirozhkov et al, AIP Proceedings, this volume]. The theory is corroborated by high-resolution two-and three-dimensional particle-in-cell simulations.

Pirozhkov, A.S.; Kando, M.; Esirkepov, T.Zh. [Advanced Beam Technology Division, Japan Atomic Energy Agency (Japan); and others

2012-07-11T23:59:59.000Z

55

Interaction of High Intensity Electromagnetic Waves with Plasmas  

SciTech Connect

The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.

G. Shvets

2008-10-03T23:59:59.000Z

56

Simulations Identify Requirements for LANL's High Intensity Laser...  

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

Identify Requirements for LANL's High Intensity Laser Lab cielo equip Fig. 1. Cielo is a 1.37 petaflops capability-class supercomputer installed at LANL, funded by the US DOE NNSA...

57

Scaling to Ultra-High Intensities by High-Energy Petawatt Beam Combining  

SciTech Connect

The output pulse energy from a single-aperture high-energy laser amplifier (e.g. fusion lasers such as NIF and LMJ) are critically limited by a number of factors including optical damage, which places an upper bound on the operating fluence; parasitic gain, which limits together with manufacturing costs the maximum aperture size to {approx} 40-cm; and non-linear phase effects which limits the peak intensity. For 20-ns narrow band pulses down to transform-limited sub-picosecond pulses, these limiters combine to yield 10-kJ to 1-kJ maximum pulse energies with up to petawatt peak power. For example, the Advanced Radiographic Capability (ARC) project at NIF is designed to provide kilo-Joule pulses from 0.75-ps to 50-ps, with peak focused intensity above 10{sup 19} W/cm{sup 2}. Using such a high-energy petawatt (HEPW) beamline as a modular unit, they discuss large-scale architectures for coherently combining multiple HEPW pulses from independent apertures, called CAPE (Coherent Addition of Pulses for Energy), to significantly increase the peak achievable focused intensity. Importantly, the maximum intensity achievable with CAPE increases non-linearly. Clearly, the total integrated energy grows linearly with the number of apertures N used. However, as CAPE combines beams in the focal plane by increasing the angular convergence to focus (i.e. the f-number decreases), the foal spot diameter scales inversely with N. Hence the peak intensity scales as N{sup 2}. Using design estimates for the focal spot size and output pulse energy (limited by damage fluence on the final compressor gratings) versus compressed pulse duration in the ARC system, Figure 2 shows the scaled focal spot intensity and total energy for various CAPE configurations from 1,2,4, ..., up to 192 total beams. They see from the fixture that the peak intensity for event modest 8 to 16 beam combinations reaches the 10{sup 21} to 10{sup 22} W/cm{sup 2} regime. With greater number of apertures, or with improvements to the focusability of the individual beams, the maximum peak intensity can be increased further to {approx} 10{sup 24} W/cm{sup 2}. Lastly, an important feature of the CAPE architecture is the ability to coherently combine beams to produce complex spatio-temporal intensity distributions for laser-based accelerators (e.g. all-optical electron injection and acceleration) and high energy density science applications such as fast ignition.

Siders, C W; Jovanovic, I; Crane, J; Rushford, M; Lucianetti, A; Barty, C J

2006-06-23T23:59:59.000Z

58

E-beam ionized channel guiding of an intense relativistic electron beam  

DOE Patents (OSTI)

An Intense Relativistic Electron Beam (IREB) is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path.

Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

1986-04-25T23:59:59.000Z

59

Nonsequential double ionization below laser-intensity threshold: Anticorrelation of electrons without excitation of parent ion  

SciTech Connect

Two-electron correlated spectra of nonsequential double ionization below laser-intensity threshold are known to exhibit back-to-back scattering of the electrons, i.e., the anticorrelation of the electrons. Currently, the widely accepted interpretation of the anticorrelation is recollision-induced excitation of the ion plus subsequent field ionization of the second electron. We argue that another mechanism, namely, simultaneous electron emission, when the time of return of the rescattered electron is equal to the time of liberation of the bounded electron (i.e., the ion has no time for excitation), can also explain the anticorrelation of the electrons in the deep, below laser-intensity threshold regime. Our conclusion is based on the results of the numerical solution of the time-dependent Schroedinger equation for a model system of two one-dimensional electrons, as well as on an adiabatic analytic model that allows for a closed-form solution.

Bondar, D. I. [University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada); Yudin, G. L. [National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada); Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada); Liu, W.-K. [University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Ivanov, M. Yu. [Imperial College, London SW7 2BW (United Kingdom); Bandrauk, A. D. [Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada)

2011-01-15T23:59:59.000Z

60

HIGH-INTENSITY EFFECTS IN THE LONGITUDINAL MOTION OF STORED PARTICLE BEAMS  

SciTech Connect

A brief review is given of the various self-field phenomena associated with the longitudinal motion of particles in storage rings. Although there are some high-intensity phenomena for which the coupling of longitudinal and transverse motion is essential, such as, for example, the headtail effect; the great majority of high-intensity phenomena primarily involve either longitudinal or transverse degrees of freedom. In this review, we restrict our attention to phenomena which are essentially longitudinal in nature. It is convenient to consider separately the behavior of unbunched (coasting) and bunched (external RF system in operation) beams. Detailed experimental information on coasting beams has been obtained on the ISR, on the (old) CERN electron model CESAR, and on electron ring accelerators. All high-energy electron storage rings have bunched beams and, of course, so do synchrotrons, so that there are a large number of sources of experimental information about the longitudinal motion of bunched beams.

Sessler, Andrew M.

1973-02-01T23:59:59.000Z

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


61

On the high intensity aspects of AGS Booster proton operation  

SciTech Connect

Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

1993-06-01T23:59:59.000Z

62

On the high intensity aspects of AGS Booster proton operation  

SciTech Connect

Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

1993-01-01T23:59:59.000Z

63

High intensity performance and upgrades at the Brookhaven AGS  

SciTech Connect

The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster. All modifications associated with this are discussed.

Roser, T.

1998-12-01T23:59:59.000Z

64

Drift tube suspension for high intensity linear accelerators  

DOE Patents (OSTI)

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

1980-03-11T23:59:59.000Z

65

Critical design issues of high intensity proton linacs  

SciTech Connect

Medium-energy proton linear accelerators are being studied as drivers for spallation applications requiring large amounts of beam powder. Important design factors for such high-intensity linacs are reviewed, and issues and concerns specific to this unprecedented power regime are discussed.

Lawrence, G.P.

1994-08-01T23:59:59.000Z

66

Drift tube suspension for high intensity linear accelerators  

SciTech Connect

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, Donald J. (Los Alamos, NM); Schamaun, Roger G. (Los Alamos, NM); Clark, Donald C. (Los Alamos, NM); Potter, R. Christopher (Los Alamos, NM); Frank, Joseph A. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

67

Some Intensive and Extensive Quantities in High-Energy Collisions  

E-Print Network (OSTI)

We review the evolution of some statistical and thermodynamical quantities measured in difference sizes of high-energy collisions at different energies. We differentiate between intensive and extensive quantities and discuss the importance of their distinguishability in characterizing possible critical phenomena of nuclear collisions at various energies with different initial conditions.

Tawfik, A

2013-01-01T23:59:59.000Z

68

ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS  

SciTech Connect

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

Qiu, Rui

2011-03-21T23:59:59.000Z

69

BEAM HALO FORMATION IN HIGH-INTENSITY BEAMS.  

SciTech Connect

Studies of beam halo became unavoidable feature of high-intensity machines where uncontrolled beam loss should be kept to extremely small level. For a well controlled stable beam such a loss is typically associated with the low density halo surrounding beam core. In order to minimize uncontrolled beam loss or improve performance of an accelerator, it is very important to understand what are the sources of halo formation in a specific machine of interest. The dominant mechanisms are, in fact, different in linear accelerators, circular machines or Energy Recovering Linacs (ERL). In this paper, we summarize basic mechanisms of halo formation in high-intensity beams and discuss their application to various types of accelerators of interest, such as linacs, rings and ERL.

FEDOTOV, A.V.

2005-03-18T23:59:59.000Z

70

Measurements of electron density and temperature in the H-1 heliac plasma by helium line intensity ratios  

Science Conference Proceedings (OSTI)

Electron density and temperature distributions in the H-1 heliac plasma are measured using the helium line intensity ratio technique based on a collisional-radiative model. An inversion approach with minimum Fisher regularization is developed to reconstruct the ratios of the local emission radiances from detected line-integrated intensities. The electron density and temperature inferred from the He I 667.8/728.1 and He I 728.1/706.5 nm line ratios are in good agreement with those from other diagnostic techniques in the inner region of the plasma. The electron density and temperature values appear to be a little high in the outer region of the plasma. Some possible causes of the discrepancy in the outer region are discussed.

Ma Shuiliang; Howard, John; Blackwell, Boyd D.; Thapar, Nandika [Plasma Research Laboratory, Australian National University, Canberra ACT 0200 (Australia)

2012-03-15T23:59:59.000Z

71

HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS  

SciTech Connect

We present experimental data of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using the Rutherford Appleton Laboratory Vulcan petawatt laser. These measurements were made using a CCD-based magnetic spectrometer. We present details on the distinct effective temperatures that were obtained for a wide variety of targets as a function of laser intensity. It is found that as the intensity increases from 10{sup 17} W/cm{sup 2} to 10{sup 19} W/cm{sup 2}, a 0.4 dependence on the laser intensity is found. Between 10{sup 19} W/cm{sup 2} and 10{sup 20} W/cm{sup 2}, a gradual rolling off of temperature with intensity is observed.

Chen, H; Wilks, S C; Kruer, W L; Moon, S; Patel, N; Patel, P K; Shepherd, R; Snavely, R

2005-12-08T23:59:59.000Z

72

Development of a high intensity EBIT for basic and applied science/011  

Science Conference Proceedings (OSTI)

The electron-beam ion trap (EBIT) is a device for producing and studying cold, very highly charged ions of any element, up to a fully ionized U{sup 92+}. These highly charged ions occur in hot plasmas and therefore play important roles in nuclear weapons, controlled fusion, and astrophysical phenomena. The remarkable interaction of these ions with surfaces may lead to technological applications. The highly charged ions can either be studied inside the EBIT itself with measurements of their x-ray emission spectra, or the ions can be extracted from the EBIT in order to study their interaction with solid material. Both types of measurements are being pursued vigorously with the two existing low-intensity EBITs at LLNL and with similar EBITs that have been built at six other laboratories around the world since the EBIT was first developed at LLNL 10 years ago. However, all existing EBITs have approximately the same intensity as the original LLNL EBIT; that is, they all produce about the same number of very-highly-charged ions (roughly 2 x 10{sup 6} per second) and the same number of x-ray photons (roughly 10{sup 7} per second). The goal of the High-Intensity-EBIT project is to increase the x-ray emission per centimeter of length along the electron beam by a factor of 100 and to increase the ion output by a factor of 1000. This dramatic increase in intensity will enable the next generation of basic and applied experimental research in the structure of highly charged ions. For example, the precision of EBIT x-ray measurements of atomic energy levels- which is now limited by count rate-can be improved by an order of magnitude, and new applications in surface science, nanotechnology, and microscopy will be possible with the expected intense ion beams. When the high ion output is combined with the demonstrated low emittance of EBIT ions, we will have a high-brightness source of highly charged ions that can be focused to submicrometer spots. One example of a measurement that will benefit from increased x-ray intensity is our study of the binding energy of high-Z heliumlike ions. The small ``two-electron`` contribution to this binding energy is a fundamental aspect of atomic structure. It arises from the small forces that the two electrons exert on each other in the presence of the much larger force from the atomic nucleus. Our existing EBIT measurements are sensitive to the so-called ``second order`` contribution to the two-electron binding energy, but with the High-Intensity EBIT we can probe an even more subtle effect: the screening by one electron of the quantum electrodynamic (QED) energy contribution from the other electron.

Marrs, R.E., LLNL

1998-02-05T23:59:59.000Z

73

Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries  

SciTech Connect

This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silica high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 ?m) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.

Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

2006-11-14T23:59:59.000Z

74

HIGH INTENSITY PERFORMANCE AND UPGRADES AT THE BROOKHAVEN AGS  

SciTech Connect

Fig. 1 shows the present layout of the AGS-RHIC accelerator complex. The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster[1]. In Fig. 2 the history of the AGS intensity improvements is shown and the major upgrades are indicated. The AGS Booster has one quarter the circumference of the AGS and therefore allows four Booster beam pulses to be stacked in the AGS at an injection energy of 1.5--1.9 GeV. At this increased energy, space charge forces are much reduced and this in turn allows for the dramatic increase in the AGS beam intensity. The 200 MeV LINAC is being used both for the injection into the Booster as well as an isotope production facility. A recent upgrade of the LINAC rf system made it possible to operated at an average H{sup {minus}} current of 150 {micro}A and a maximum of 12 x 10{sup 13} H{sup {minus}} per 500 {micro}s LINAC pulse for the isotope production target. Typical beam currents during the 500 {micro}s pulse are about 80 mA at the source, 60 mA after the 750 keV RFQ, 38 mA after the first LINAC tank (10 MeV), and 37 mA at end of the LINAC at 200 MeV. The normalized beam emittance is about 2 {pi} mm mrad for 95% of the beam and the beam energy spread is about {+-}1.2 MeV. A magnetic fast chopper installed at 750 keV allows the shaping of the beam injected into the Booster to avoid excessive beam loss.

ROSER,T.

1998-05-04T23:59:59.000Z

75

CW high intensity non-scaling FFAG proton drivers  

SciTech Connect

Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider). These high-intensity GeV-range proton drivers are particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive alternative to the cyclotron. Its strong focusing optics are expected to mitigate space charge effects, and a recent innovation in design has coupled stable tunes with isochronous orbits, making the FFAG capable of fixed-frequency, CW acceleration, as in the classical cyclotron. This paper reports on these new advances in FFAG accelerator technology and references advanced modeling tools for fixed-field accelerators developed for and unique to the code COSY INFINITY.

Johnstone, C.; /Fermilab; Berz, M.; Makino, K.; /Michigan State U.; Snopok, P.; /IIT, Chicago

2011-04-01T23:59:59.000Z

76

Intensity-dependent enhancements in high-order above-threshold ionization  

Science Conference Proceedings (OSTI)

The very pronounced intensity-dependent enhancements of groups of peaks of high-order above-threshold-ionization spectra of rare-gas atoms are investigated using an improved version of the strong-field approximation, which realistically models the respective atom. Two types of enhancements are found and explained in terms of constructive interference of the contributions of a large number of long quantum orbits. The first type is observed for intensities slightly below channel closings. Its intensity dependence is comparatively smooth and it is generated by comparatively few (of the order of 20) orbits. The second type occurs precisely at channel closings and exhibits an extremely sharp intensity dependence. It requires constructive interference of a very large number of long orbits (several hundreds) and generates cusps in the electron spectrum at integer multiples of the laser-photon energy. An interpretation of these enhancements as a threshold phenomenon is also given. An interplay of different types of the threshold anomalies is observed. The position of both types of enhancements, in the photoelectron-energy--laser-intensity plane, shifts to the next channel closing intensity with the change of the ground-state parity. The enhancements gradually disappear with decreasing laser pulse duration. This confirms the interpretation of enhancements as a consequence of the interference of long strong-laser-field-induced quantum orbits.

Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany); Hasovic, E.; Gazibegovic-Busuladzic, A. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina); Busuladzic, M. [Medical Faculty, University of Sarajevo, Cekalusa 90, 71000 Sarajevo (Bosnia and Herzegowina); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2007-11-15T23:59:59.000Z

77

Images of Complex Interactions of an Intense Ion Beam with Plasma Electrons  

SciTech Connect

Ion beam propagation in a background plasma is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because plasma electrons move in strong electric and magnetic fields of the beam. Computer simulation images of plasma interaction with an intense ion beam pulse are presented.

Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

2004-08-03T23:59:59.000Z

78

Acceleration of electrons by a circularly polarized laser pulse in the presence of an intense axial magnetic field in vacuum  

Science Conference Proceedings (OSTI)

Acceleration of electrons by a circularly polarized laser pulse in the presence of a short duration intense axial magnetic field has been studied. Resonance occurs between the electrons and the laser field for an optimum magnetic field leading to effective energy transfer from laser to electrons. The value of optimum magnetic field is independent of the laser intensity and decreases with initial electron energy. The electrons rotate around the axis of the laser pulse with small angle of emittance and small energy spread. Acceleration gradient increases with laser intensity and decreases with initial electron energy.

Singh, K. P. [Computational Plasma Dynamics Laboratory, Kettering University, Flint, Michigan 48504 (United States)

2006-08-15T23:59:59.000Z

79

HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS  

Science Conference Proceedings (OSTI)

Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

2008-10-08T23:59:59.000Z

80

Summary of sessions B and F: High intensity linacs and frontend & proton drivers  

SciTech Connect

This paper summarizes the sessions B&F of the 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity & High Brightness Hadron Beams held in Bensheim, Germany. It covers high intensity linacs, front ends and proton driver topics.

Ferdinand, R.; /Saclay; Chou, W.; /Fermilab; Galambos, J.; /Oak Ridge

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity electron" from the National Library of EnergyBeta (NLEBeta).
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81

A Plasma Lens for High Intensity Laser Focusing  

SciTech Connect

A plasma lens based on a short hydrogen-filled alumina capillary discharge is experimentally characterized. For a plasma length of about 5mm, the focal length, measured from the plasma entrance, was {approx} 11 to 8mm for on axis densities of {approx} 2.5 to 5 x 1018cm-3, respectively. The plasma temperature away from the walls of the 1/2mm diameter capillary was estimated to be {approx} 8eV indicating that the plasma is fully ionized. Such a lens should thus be suitable for focusing very high intensity pulses. Comparisons of the measured focusing strength to that predicted by a first-order fluid model [N. A. Bobrova, et al., Phys. Rev. E 65, 016407 (2002)] shows reasonable agreement given that some of the observed plasma parameters are not predicted by this model.

Fang, F.; Clayton, C. E.; Marsh, K. A.; Joshi, C. [UCLA Department of Electrical Engineering, Los Angeles, CA, 90095 (United States); Lopes, N. C. [Grupo de Lasers e Plasmas, ESuperior Tecnico, Lisbon (Portugal); Ito, H. [Utsunomiya University, 7-1-2 Yoto, Utsunomiya City, Zip 321-8585 (Japan)

2006-11-27T23:59:59.000Z

82

HIGH INTENSITY LIGHT SOURCES (Part II of Thesis)  

SciTech Connect

A stable carbon arc operated in controlled atmosphere is described. The arc was designed to serve as a light source during lifetime studies of the B/sup 2/ SIGMA state of the CN molecule. The CN radiation from the plasma of the arc was investigated and found to have a brightness temperature of 5500 icient laborato K at lambda 3883 A. This is considerably higher than an estimate of the value required for lifetime measurements. The stability of the carbon arc under various conditions is discussed. For successful lifetime measurements, the light source employed must have a high brightness temperature (intensity). A method for the determination of the brightness temperature of a light source at a specific wave length is described. The method was used for determining the brightness temperatures of some available light sources. Sodium, thallium, and mercury discharge lamps, a medium-pressure mercury arc lamp, and the carbon arc were studied. (auth)

Worden, E.F. Jr.

1958-10-01T23:59:59.000Z

83

Comoving acceleration of overdense electron-positron plasma by colliding ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Particle-in-cell (PIC) simulation results of sustained acceleration of electron-positron (e+e-) plasmas by comoving electromagnetic (EM) pulses are presented. When a thin slab of overdense e+e- plasma is irradiated with linear-polarized ultra-intense short laser pulses from both sides, the pulses are transmitted when the plasma is compressed to thinner than {approx}2 relativistic skin depths. A fraction of the plasma is then captured and efficiently accelerated by self-induced JxB forces. For 1 {mu}m laser and 10{sup 21} W cm{sup -2} intensity, the maximum energy exceeds GeV in a picosecond.

Liang, Edison [Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

2006-06-15T23:59:59.000Z

84

Frequency conversion of high-intensity, femtosecond laser pulses  

SciTech Connect

Almost since the invention of the laser, frequency conversion of optical pulses via non- linear processes has been an area of active interest. However, third harmonic generation using ~(~1 (THG) in solids is an area that has not received much attention because of ma- terial damage limits. Recently, the short, high-intensity pulses possible with chirped-pulse amplification (CPA) laser systems allow the use of intensities on the order of 1 TW/cm2 in thin solids without damage. As a light source to examine single-crystal THG in solids and other high field inter- actions, the design and construction of a Ti:sapphire-based CPA laser system capable of ultimately producing peak powers of 100 TW is presented. Of special interest is a novel, all-reflective pulse stretcher design which can stretch a pulse temporally by a factor of 20,000. The stretcher design can also compensate for the added material dispersion due to propagation through the amplifier chain and produce transform-limited 45 fs pulses upon compression. A series of laser-pumped amplifiers brings the peak power up to the terawatt level at 10 Hz, and the design calls for additional amplifiers to bring the power level to the 100 TW level for single shot operation. The theory for frequency conversion of these short pulses is presented, focusing on conversion to the third harmonic in single crystals of BBO, KD*P, and d-LAP (deuterated I-arginine phosphate). Conversion efficiencies of up to 6% are obtained with 500 fs pulses at 1053 nm in a 3 mm thick BBO crystal at 200 GW/cm 2. Contributions to this process by unphasematched, cascaded second harmonic generation and sum frequency generation are shown to be very significant. The angular relationship between the two orders is used to measure the tensor elements of C = xt3)/4 with Crs = -1.8 x 1O-23 m2/V2 and .15Cri + .54Crs = 4.0 x 1O-23 m2/V2. Conversion efficiency in d-LAP is about 20% that in BBO and conversion efficiency in KD*P is 1% that of BBO. It is calculated that conversion efficiencies of 30-40% are possible at intensities of 600-800 GW/cm2, which is the operating level of the Petawatt laser at LLNL. The main limiting factors are phase modulation and material damage.

Banks, P S

1997-06-01T23:59:59.000Z

85

Space charge measurements with a high intensity bunch at the Fermilab Main Injector  

SciTech Connect

For Project X, the Fermilab Main Injector will be required to operate with 3 times higher bunch intensity. The plan to study the space charge effects at the injection energy with intense bunches will be discussed. A multi-MW proton facility has been established as a critical need for the U.S. HEP program by HEPAP and P5. Utilization of the Main Injector (MI) as a high intensity proton source capable of delivering in excess of 2 MW beam power will require a factor of three increase in bunch intensity compared to current operations. Instabilities associated with beam loading, space charge, and electron cloud effects are common issues for high intensity proton machines. The MI intensities for current operations and Project X are listed in Table 1. The MI provides proton beams for Fermilab's Tevatron Proton-Antiproton Collider and MINOS neutrino experiments. The proposed 2MW proton facility, Project X, utilizes both the Recycler (RR) and the MI. The RR will be reconfigured as a proton accumulator and injector to realize the factor 3 bunch intensity increase in the MI. Since the energy in the RR and the MI at injection will be 6-8 GeV, which is relatively low, space charge effects will be significant and need to be studied. Studies based on the formation of high intensity bunches in the MI will guide the design and fabrication of the RF cavities and space-charge mitigation devices required for 2 MW operation of the MI. It is possible to create the higher bunch intensities required in the MI using a coalescing technique that has been successfully developed at Fermilab. This paper will discuss a 5 bunch coalescing scheme at 8 GeV which will produce 2.5 x 10{sup 11} protons in one bunch. Bunch stretching will be added to the coalescing process. The required RF parameters were optimized with longitudinal simulations. The beam studies, that have a goal of 85% coalescing efficiency, were started in June 2010.

Seiya, K.; Chase, B.; Dey, J.; Joireman, P.; Kourbanis, I.; /Fermilab; Yagodnitsyna, A.; /Novosibirsk State U.

2011-03-01T23:59:59.000Z

86

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

SciTech Connect

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

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

1995-05-01T23:59:59.000Z

87

Compton harmonic resonances, stochastic instabilities, quasilinear diffusion, and collisionless damping with ultra-high intensity laser waves  

SciTech Connect

The dynamics of electrons in two-dimensional, linearly or circularly polarized, ultra-high intensity (above 10{sup 18}W/cm{sup 2}) laser waves, is investigated. The Compton harmonic resonances are identified as the source of various stochastic instabilities. Both Arnold diffusion and resonance overlap are considered. The quasilinear kinetic equation, describing the evolution of the electron distribution function, is derived, and the associated collisionless damping coefficient is calculated. The implications of these new processes are considered and discussed.

Rax, J.M.

1992-04-01T23:59:59.000Z

88

High temperature electronic gain device  

SciTech Connect

An integrated thermionic device suitable for use in high temperature, high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube.

McCormick, J. Byron (Los Alamos, NM); Depp, Steven W. (Los Alamos, NM); Hamilton, Douglas J. (Tucson, AZ); Kerwin, William J. (Tucson, AZ)

1979-01-01T23:59:59.000Z

89

Creating intense polarized electron beam via laser stripping and spin-orbit interaction  

DOE Green Energy (OSTI)

The recent advance in laser field make it possible to excite and strip electrons with definite spin from hydrogen atoms. The sources of hydrogen atoms with orders of magnitude higher currents (than that of the conventional polarized electron cathods) can be obtained from H{sup -} sources with good monochromatization. With one electron of H{sup -} stripped by a laser, the remained electron is excited to upper state (2P{sup 3/2} and 2P{sup 1/2}) by a circular polarization laser light from FEL. Then, it is excited to a high quantum number (n=7) with mostly one spin direction due to energy level split of the states with a definite direction of spin and angular momentum in an applied magnetic field and then it is stripped by a strong electric field of an RF cavity. This paper presents combination of lasers and fields to get high polarization and high current electron source.

Danilov, V.; Ptitsyn, V.; Gorlov, T.

2010-12-01T23:59:59.000Z

90

High intensity production of high and medium charge state uraniumand other heavy ion beams with VENUS  

SciTech Connect

The next generation, superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) started operation with 28GHzmicrowave heating in 2004. Since then it has produced world recordion beam intensities. For example, 2850 e mu A of O6+, 200 e mu A of U33+or U34+, and in respect to high charge state ions, 1 e mu A of Ar18+, 270e mu A of Ar16+, 28 e mu A of Xe35+ and 4.9 e mu A of U47+ have beenproduced. A brief overview of the latest developments leading to theserecord intensities is given and the production of high intensity uraniumbeams is discussed in more detail.

Leitner, Daniela; Galloway, Michelle L.; Loew, Timothy J.; Lyneis, Claude M.; Rodriguez, Ingrid Castro; Todd, Damon S.

2007-11-15T23:59:59.000Z

91

Max Tech and Beyond: High-Intensity Discharge Lamps  

Science Conference Proceedings (OSTI)

High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable operating conditions, and this necessitates additional power beyond that used by the lamp itself. HID lamps offer important advantages compared to other lighting technologies, making them well suited for certain applications. HID lamps can be very efficient, have long operating lives, are relatively temperature-insensitive and produce a large quantity of light from a small package. For these reasons, HID lamps are often used when high levels of illumination are required over large areas and where operating and maintenance costs must be kept to a minimum. Furthermore, if the installation has a significant mounting height, high-power HID lamps can offer superior optical performance luminaires, reducing the number of lamps required to illuminate a given area. The indoor environments best suited to HID lamps are those with high ceilings, such as those commonly found in industrial spaces, warehouses, large retail spaces, sports halls and large public areas. Research into efficacy improvements for HID lighting technologies has generally followed market demand for these lamps, which is in decline for MV and LPS, has reached a plateau for HPS and is growing for MH. Several manufacturers interviewed for this study indicated that although solid-state lighting was now receiving the bulk of their company's R&D investment, there are still strong HID lamp research programs, which concentrate on MH technologies, with some limited amount of investment in HPS for specific niche applications (e.g., agricultural greenhouses). LPS and MV lamps are no longer being researched or improved in terms of efficacy or other performance attributes, although some consider MH HID lamps to be the next-generation MV lamp. Thus, the efficacy values of commercially available MV, LPS and HPS lamps are not expected to increase in the next 5 to 10 years. MH lamps, and more specifically, ceramic MH lamps are continuing to improve in efficacy as well as light quality, manufacturability and lamp life. Within an HID lamp, the light-producing plasma must be heated to sufficiently high temperatures to achieve high efficiencie

Scholand, Michael

2012-04-01T23:59:59.000Z

92

Delivery confirmation of bolus electron conformal therapy combined with intensity modulated x-ray therapy  

Science Conference Proceedings (OSTI)

Purpose: The purpose of this study was to demonstrate that a bolus electron conformal therapy (ECT) dose plan and a mixed beam plan, composed of an intensity modulated x-ray therapy (IMXT) dose plan optimized on top of the bolus ECT plan, can be accurately delivered. Methods: Calculated dose distributions were compared with measured dose distributions for parotid and chest wall (CW) bolus ECT and mixed beam plans, each simulated in a cylindrical polystyrene phantom that allowed film dose measurements. Bolus ECT plans were created for both parotid and CW PTVs (planning target volumes) using 20 and 16 MeV beams, respectively, whose 90% dose surface conformed to the PTV. Mixed beam plans consisted of an IMXT dose plan optimized on top of the bolus ECT dose plan. The bolus ECT, IMXT, and mixed beam dose distributions were measured using radiographic films in five transverse and one sagittal planes for a total of 36 measurement conditions. Corrections for film dose response, effects of edge-on photon irradiation, and effects of irregular phantom optical properties on the Cerenkov component of the film signal resulted in high precision measurements. Data set consistency was verified by agreement of depth dose at the intersections of the sagittal plane with the five measured transverse planes. For these same depth doses, results for the mixed beam plan agreed with the sum of the individual depth doses for the bolus ECT and IMXT plans. The six mean measured planar dose distributions were compared with those calculated by the treatment planning system for all modalities. Dose agreement was assessed using the 4% dose difference and 0.2 cm distance to agreement. Results: For the combined high-dose region and low-dose region, pass rates for the parotid and CW plans were 98.7% and 96.2%, respectively, for the bolus ECT plans and 97.9% and 97.4%, respectively, for the mixed beam plans. For the high-dose gradient region, pass rates for the parotid and CW plans were 93.1% and 94.62%, respectively, for the bolus ECT plans and 89.2% and 95.1%, respectively, for the mixed beam plans. For all regions, pass rates for the parotid and CW plans were 98.8% and 97.3%, respectively, for the bolus ECT plans and 97.5% and 95.9%, respectively, for the mixed beam plans. For the IMXT component of the mixed beam plans, pass rates for the parotid and CW plans were 93.7% and 95.8%. Conclusions: Bolus ECT and mixed beam therapy dose delivery to the phantom were more accurate than IMXT delivery, adding confidence to the use of planning, fabrication, and delivery for bolus ECT tools either alone or as part of mixed beam therapy. The methodology reported in this work could serve as a basis for future standardization of the commissioning of bolus ECT or mixed beam therapy. When applying this technology to patients, it is recommended that an electron dose algorithm more accurate than the pencil beam algorithm, e.g., a Monte Carlo algorithm or analytical transport such as the pencil beam redefinition algorithm, be used for planning to ensure the desired accuracy.

Kavanaugh, James A. [Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States); Hogstrom, Kenneth R.; Fontenot, Jonas P.; Henkelmann, Gregory [Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 and Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States); Chu, Connel; Carver, Robert A. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 (United States)

2013-02-15T23:59:59.000Z

93

Deep Trek High Temperature Electronics Project  

Science Conference Proceedings (OSTI)

This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

Bruce Ohme

2007-07-31T23:59:59.000Z

94

Phase contrast in high resolution electron microscopy  

DOE Patents (OSTI)

This patent relates to a device for developing a phase contrast signal for a scanning transmission electron microscope. The lens system of the microscope is operated in a condition of defocus so that predictable alternate concentric regions of high and low electron density exist in the cone of illumination. Two phase detectors are placed beneath the object inside the cone of illumination, with the first detector having the form of a zone plate, each of its rings covering alternate regions of either higher or lower electron density. The second detector is so configured that it covers the regions of electron density not covered by the first detector. Each detector measures the number of electrons incident thereon and the signal developed by the first detector is subtracted from the signal developed by the record detector to provide a phase contrast signal. (auth)

Rose, H.H.

1975-09-23T23:59:59.000Z

95

High-temperature electronics: an overview  

DOE Green Energy (OSTI)

A summary is presented providing an overview of contemporary high-temperature electronics and identifying the major areas where developments are needed and the laboratories where research is being conducted. The geothermal program, high-temperature oil and gas well logging, jet engine monitors, and circuits for operation in the sodium coolant loop of the Clinch River Breeder reactor have stimulated research. (FS)

Heckman, R.C.

1979-01-01T23:59:59.000Z

96

A STUDY ON THE CHOICE OF PARAMETERS FOR A HIGH ENERGY ELECTRON RING ACCELERATOR  

SciTech Connect

The production of high energy (multi-GeV) proton beams by an electron ring accelerator is considered. Both the final energy and intensity of the proton beam depend on the choice of parameters for the electron ring. Possible sets of parameters, consistent with all the known requirements of ring stability, and which optimize the energy and (or) the intensity of the proton beam, are presented.

Bovet, C.; Pellegrini, C.

1970-06-26T23:59:59.000Z

97

Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF  

SciTech Connect

The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

Ma, T

2010-04-21T23:59:59.000Z

98

A high transmission analyzing magnet for intense high charge state beams  

DOE Green Energy (OSTI)

The low energy beam transport (LEBT) for VENUS will provide for extraction, mass analysis and transport to the axial injection line for the 88-Inch Cyclotron. The new LEBT was designed from the beginning to handle high intensity beams where space charge forces strongly affect the transmission. The magnet has a unique design with specially shaped poles to apply sextupole correction in both the horizontal and vertical plane.

Leitner, M.; Abbott, S.R.; Leitner, D.; Lyneis, C.

2002-06-11T23:59:59.000Z

99

HIGH INTENSITY LOW-ENERGY POSITRON SOURCE AT JEFFERSON  

SciTech Connect

We present a novel concept of a low-energy e{sup +} source with projected intensity on the order of 10{sup 10} slow e{sup +}/s. The key components of this concept are a continuous wave e{sup -} beam, a rotating positron-production target, a synchronized raster/anti-raster, a transport channel, and extraction of e{sup +} into a field-free area through a magnetic plug for moderation in a cryogenic solid. Components were designed in the framework of GEANT4-based (G4beamline) Monte Carlo simulation and TOSCA magnetic field calculation codes. Experimental data to demonstrate the effectiveness of the magnetic plug is presented.

Serkan Golge, Bogdan Wojtsekhowski, Branislav Vlahovic

2012-07-01T23:59:59.000Z

100

REFLECTED LIGHT INTENSITY DISTRIBUTIONS FROM DEFECTS ON HIGHLY REFLECTIVE SPHERES PDO 6984778, Topical Report  

SciTech Connect

A light reflection technique suitable for development into an automated surface quality certification system was investigated to determine if reflected light intensity distributions could be corre]ated with surface defect depths. Reflected laser light intensity distributions from pit and scratch defects on highly reflective spheres were studied with a commercial multi-element photodetector. It was found that the intensity distributions --Goll'lf be correlated with depths of pits and scratches in a size range of concern on highly reflective' spheres.

Klingsport, P. E.

1977-02-01T23:59:59.000Z

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


101

Diamondoid monolayers as electron emitters - Energy Innovation ...  

Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron ...

102

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

DOE Green Energy (OSTI)

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

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

2012-05-01T23:59:59.000Z

103

Liquid lithium target as a high intensity, high energy neutron source  

DOE Patents (OSTI)

This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

Parkin, Don M. (Los Alamos, NM); Dudey, Norman D. (Glen Ellyn, IL)

1976-01-01T23:59:59.000Z

104

High-Intensity Laser Diagnostics for OMEGA EP  

Science Conference Proceedings (OSTI)

OMEGA EP is a new high-energy petawatt laser system under construction at the University of Rochester’s Laboratory for Laser Energetics. This paper describes our designs for two diagnostics critical to OMEGA EP’s mission. The focal-spot diagnostic (FSD) is responsible for characterizing the focal spot of OMEGA EP’s off-axis parabolic mirror at full energy. The ultrafast temporal diagnostic (UTD) is responsible for characterizing pulse shapes of full-energy target shots ranging in width from petawatt laser at full energy.

Bromage, J.; Zuegel, J.D.; Bahk, S.-W.; Vickery, D.S.; Waxer, L.J.; Irwin, D.; Bagnoud, V.; Boni, R.; Moore, M.D.; Junquist, R.; Stoeckl, C.

2006-07-13T23:59:59.000Z

105

Production of intense highly charged ion beams with SERSE  

E-Print Network (OSTI)

The source SERSE is operational at LNS since June 1998 and many improvements have been carried out in this period. The frequency has been increased from 14.5 GHz to 18 GHz and the use of two frequency heating has given positive results. Metallic ion production has been tested by means of a high temperature oven and the preliminary results are described. Tests of magnetic field scaling and frequency scaling have confirmed the results of previous tests with SC-ECRIS at lower frequency and seems to suggest that the upgrading of the source to higher frequency may be considered.

Gammino, S; Ciavola, G; Castro, M; Chines, F; Marletta, S; Melin, G; Briand, P; Girard, A; Ludwig, P; Seyfert, P; Guillaume, D

1999-01-01T23:59:59.000Z

106

High-Intensity Plasma Glass Melter Final Technical Report  

Science Conference Proceedings (OSTI)

The purpose of this project was to demonstrate the energy efficiency and reduced emissions that can be obtained with a dual torch DC plasma transferred arc-melting system. Plasmelt Glass Technologies, LLC was formed to solicit and execute the project, which utilize a full-scale test melter system. The system is similar to the one that was originally constructed by Johns Manville, but Plasmelt has added significant improvements to the torch design and melter system that has extended the original JM short torch lives. The original JM design has been shown to achieve melt rates 5 to 10 times faster than conventional gas or electric melting, with improved energy efficiency and reduced emissions. This project began on 7/28/2003 and ended 7/27/06. A laboratory scale melter was designed, constructed, and operated to conduct multiple experimental melting trials on various glass compositions. Glass quality was assessed. Although the melter design is generic and equally applicable to all sectors within the glass industry, the development of this melter has focused primarily on fiberglass with additional exploratory melting trials of frits, specialty, and minerals-melting applications. Throughput, energy efficiency, and glass quality have been shown to be heavily dependent on the selected glass composition. During this project, Plasmelt completed the proof-of-concept work in our Boulder, CO Lab to show the technical feasibility of this transferred-arc plasma melter. Late in the project, the work was focused on developing the processes and evaluating the economic viability of plasma melting aimed at the specific glasses of interest to specific client companies. Post project work is on going with client companies to address broader non-glass materials such as refractories and industrial minerals. Exploratory melting trials have been conducted on several glasses of commercial interest including: C-glass, E-glass, S-Glass, AR-Glass, B-glass, Lighting Glass, NE-Glass, and various frits. Exploratory melts of non-glassy materials, such as wollastonite, zirconium silicate, and alumino-silicate melts were successfully done indicating that plasma melting has potential application beyond glass. Experimental results were generated that show the high quality of plasma-melted fiberglass compositions, such as E-glass, can result in good fiberizing performance. Fiberizing performance and tensile strength data were achieved during the project to support this conclusion. High seed counts are a feature of the current lab scale melter and must be dealt with via other means, since fining work was outside the scope of this project.

Gonterman, J. Ronald; Weinstein, Michael A.

2006-10-27T23:59:59.000Z

107

High accuracy electronic material level sensor  

DOE Patents (OSTI)

The High Accuracy Electronic Material Level Sensor (electronic dipstick) is a sensor based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line or guide wire that is partially immersed in the material being measured; a launcher plate is positioned at the beginning of the guide wire. Reflected pulses are produced at the material interface due to the change in dielectric constant. The time difference of the reflections at the launcher plate and at the material interface are used to determine the material level. Improved performance is obtained by the incorporation of: 1) a high accuracy time base that is referenced to a quartz crystal, 2) an ultrawideband directional sampler to allow operation without an interconnect cable between the electronics module and the guide wire, 3) constant fraction discriminators (CFDs) that allow accurate measurements regardless of material dielectric constants, and reduce or eliminate errors induced by triple-transit or "ghost" reflections on the interconnect cable. These improvements make the dipstick accurate to better than 0.1%.

McEwan, Thomas E. (Livermore, CA)

1997-01-01T23:59:59.000Z

108

Extremely high frequency RF effects on electronics.  

SciTech Connect

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

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

2012-01-01T23:59:59.000Z

109

High resolution electron crystallography of protein molecules  

Science Conference Proceedings (OSTI)

Electron diffraction data and high resolution images can now be used to obtain accurate, three-dimensional density maps of biological macromolecules. These density maps can be interpreted by building an atomic-resolution model of the structure into the experimental density. The Cowley-Moodie formalism of dynamical diffraction theory has been used to validate the use of kinematic diffraction theory, strictly the weak phase object approximation, in producing such 3-D density maps. Further improvements in the preparation of very flat specimens and in the retention of diffraction to a resolution of 0.2 nm or better could result in electron crystallography becoming as important a technique as x-ray crystallography currently is for the field of structural molecular biology.

Glaeser, R.M. [California Univ., Berkeley, CA (United States). Dept. of Molecular and Cell Biology]|[Lawrence Berkeley Lab., CA (United States); Downing, K.H. [Lawrence Berkeley Lab., CA (United States)

1993-06-01T23:59:59.000Z

110

High-intensity, high-brightness polarized and unpolarized beam production in charge-exchange collisions  

DOE Green Energy (OSTI)

Basic limitations on the high-intensity H{sup -} ion beam production were experimentally studied in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapour jet ionizer cell. These studies are the part of the polarized source upgrade (to 10 mA peak current and 85% polarization) project for RHIC. In the source the atomic hydrogen beam of a 5-10 keV energy and total (equivalent) current up to 5 A is produced by neutralization of proton beam in pulsed hydrogen gas target. Formation of the proton beam (from the surface of the plasma emitter with a low transverse ion temperature {approx}0.2 eV) is produced by four-electrode spherical multi-aperture ion-optical system with geometrical focusing. The hydrogen atomic beam intensity up to 1.0 A/cm{sup 2} (equivalent) was obtained in the Na-jet ionizer aperture of a 2.0 cm diameter. At the first stage of the experiment H-beam with 36 mA current, 5 keV energy and {approx}1.0 cm {center_dot} mrad normalized emittance was obtained using the flat grids and magnetic focusing.

Zelenski, A.; Ritter, J.; Zubets, V.; Steski, D.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.

2011-03-28T23:59:59.000Z

111

IT-intensive value innovation in the electronic economy: insights from Marshall industries  

Science Conference Proceedings (OSTI)

Keywords: CIO, IT architecture, Internet, distribution industry, e-business, electronic commerce, electronic economy, electronic value chains, extranet, fast-response, intermediation, intranet, strategic information systems, supply chain management, systems approach, time-based competition, total quality management, value innovation

Omar A. El Sawy; Arvind Malhotra; Sanjay Gosain; Kerry M. Young

1999-09-01T23:59:59.000Z

112

STATUS OF SLOW EXTRACTION OF HIGH INTENSITY PROTONS FROM BROOKHAVEN'S AGS.  

SciTech Connect

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams. We have an active program of high energy physics experiments, including the high precision measurement of the muons magnetic moment [1] and the discovery of the rare Kaon decay, K+ {yields} {pi} + {nu}{bar {nu}} [2]. This program is continuing into the future with the rare symmetry violating process experiments [3] currently being designed to operate at the AGS. In this paper, we will present results from operation of high intensity slow extraction, the problems we encounter, and our solutions to those problems.

BROWN,K.A.AHRENS,L.BRENNAN,J.M.GLENN,J.W.ROSER,T.RUSSO,T.TSOUPAS,N.SMITH,K.ZENO,K.

2003-05-12T23:59:59.000Z

113

Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma  

DOE Green Energy (OSTI)

The results of an experimental study on the trapping and energy loss mechanisms of intense, relativistic electron rings confined in Astron-like magnetic field geometries are presented. The work is subdivided into four sections: gas trapping; average ring electron energetics; plasma trapping, and hollow-beam cusp-injection into gas and plasma. The mechanisms by which the injected beam coalesces into a current ring in the existing Cornell RECE-Berta facility are considered. To investigate the nature of ring electron energy loss mechanisms following completion of the trapping process, a diagnostic was developed utilizing multi-foil X-ray absorption spectroscopy to analyze the Bremsstrahlung generated by the electrons as they impinge upon a thin tungsten wire target suspended in the circulating current. Finally, a set of preliminary experimental results is presented in which an annular electron beam was passed through a coaxial, non-adiabatic magnetic cusp located at one end of a magnetic mirror well.

Smith, A.C. Jr.

1977-04-25T23:59:59.000Z

114

Collective Focusing of Intense Ion Beam Pulses for High-energy Density Physics Applications  

SciTech Connect

The collective focusing concept in which a weak magnetic lens provides strong focusing of an intense ion beam pulse carrying a neutralizing electron background is investigated by making use of advanced particle-in-cell simulations and reduced analytical models. The original analysis by Robertson Phys. Rev. Lett. 48, 149 (1982) is extended to the parameter regimes of particular importance for several high-energy density physics applications. The present paper investigates (1) the effects of non-neutral collective focusing in a moderately strong magnetic field; (2) the diamagnetic effects leading to suppression of the applied magnetic field due to the presence of the beam pulse; and (3) the influence of a finite-radius conducting wall surrounding the beam cross-section on beam neutralization. In addition, it is demonstrated that the use of the collective focusing lens can significantly simplify the technical realization of the final focusing of ion beam pulses in the Neutralized Drift Compression Experiment-I (NDCX-I) , and the conceptual designs of possible experiments on NDCX-I are investigated by making use of advanced numerical simulations. 2011 American Institute of Physics

Mikhail A. Dorf, Igor D. Kaganovich, Edward A. Startsev and Ronald C. Davidson

2011-04-27T23:59:59.000Z

115

Improved Heat Transfer and Performance of High Intensity Combustion Systems for Reformer Furnace Applications  

E-Print Network (OSTI)

Developments over the past fifteen years have evolved new short flame, high intensity (1,000,000 BTU/HR/ft3 ) combustion systems for industrial uses. Such systems produce a more uniform and higher heat flux than conventional low intensity systems and should enable substantial capital cost savings in new furnace applications. Recent performance improvements established from tests of high intensity combustion systems are described along with advances made in the analytical prediction of design performance. High intensity combustion systems can operate at zero excess air conditions without generating undesirable constituents in the exhaust. A more uniform gas temperature and gas emissivity renders modeling and design of the furnace radiant heat transfer section more realistic. 'Over-design' to allow for the less determinate conditions typical of low intensity, turbulent diffusion oil flame systems should be avoidable. A model has been set up and results generated which indicate the potentialities of the above premise. The application of vortex stabilized high intensity burners for reformer furnaces in the petrochemical industry is then reviewed and emphasized.

Williams, F. D. M.; Kondratas, H. M.

1983-01-01T23:59:59.000Z

116

Electron Linacs for High Energy Physics  

Science Conference Proceedings (OSTI)

The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

Wilson, Perry B.; /SLAC

2011-11-08T23:59:59.000Z

117

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths  

SciTech Connect

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15T23:59:59.000Z

118

Generation of high intensity rf pulses in the ionosphere by means of in situ compression  

SciTech Connect

We demonstrate, using a simple model, that high intensity pulses can be generated from a frequency-chirped modifier of much lower intensity by making use of the dispersive properties of the ionosphere. We show that a frequency-chirped pulse can be constructed so that its various components overtake each other at a prescribed height, resulting in large (up to one hundred times) transient intensity enhancements as compared to those achievable from a steady modifier operating at the same power. We examine briefly one possible application: the enhancement of plasma wave amplitudes which occurs as a result of the interaction of such a compressed pulse with pre-generated turbulence.

Cowley, S.C.; Perkins, F.W.; Valeo, E.J.

1993-04-01T23:59:59.000Z

119

Metrology of High Current Density Electron Field Emitters  

Science Conference Proceedings (OSTI)

... through a biasing grid. These thermal electron sources have limitations due to the required high operating temperature, power consumption, and ...

2012-07-10T23:59:59.000Z

120

Overview of the High Intensity Neutrino Source Linac R&D program at Fermilab  

SciTech Connect

The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is building a first-of-a-kind 60 MeV superconducting H- linac. The HINS Linac incorporates superconducting solenoids for transverse focusing, high power RF vector modulators for independent control of multiple cavities powered from a single klystron, and superconducting spoke-type accelerating cavities starting at 10 MeV. This will be the first application and demonstration of any of these technologies in a low-energy, high-intensity proton/H- linear accelerator. The HINS effort is relevant to a high intensity, superconducting H- linac that might serve the next generation of neutrino physics and muon storage ring/collider experiments. An overview of the HINS program, machine design, status, and outlook is presented.

Webber, R.C.; Appollinari, G.; Carneiro, J.P.; Gonin, I.; Hanna, B.; Hays, S.; Khabiboulline, T.; Lanfranco, G.; Madrak, R.L.; Moretti, A.; Nicol, T.; /Fermilab /Argonne

2008-09-01T23:59:59.000Z

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


121

High Performance Wide Bandgap Power Electronics  

Science Conference Proceedings (OSTI)

Symposium, Advanced Materials for Power Electronics, Power Conditioning, and ... therefore, designers unknowingly navigate the design space with a lack of ...

122

Magnetic Materials for High Frequency Power Electronics  

Science Conference Proceedings (OSTI)

Mar 7, 2013 ... Advanced Materials for Power Electronics, Power Conditioning, and Power ... in power conditioning, conversion, and generation applications.

123

AlSb/InAs HIGH ELECTRON MOBILITY TRANSISTORS - Energy ...  

The Naval Research Laboratory (NRL) has developed materials growth and fabrication technology for the manufacture of high-speed, low power AlSb/InAs high electron ...

124

High-Flying Electrons May Provide New Test of Quantum ...  

Science Conference Proceedings (OSTI)

... propose engineering so-called hydrogen-like Rydberg atoms—atomic nuclei stripped of all but a single electron in a high-lying energy level far ...

2011-07-18T23:59:59.000Z

125

Hot-electron production and suprathermal heat flux scaling with laser intensity from the two-plasmon-decay instability  

SciTech Connect

The fully kinetic reduced-description particle-in-cell (RPIC) method has been applied to simulations of two-plasmon-decay (TPD) instability, driven by crossed laser beams, in an inhomogeneous plasma for parameters consistent with recent direct-drive experiments related to laser-driven inertial fusion. The nonlinear saturated state is characterized by very spiky electric fields, with Langmuir cavitation occurring preferentially inside density channels produced by the ponderomotive beating of the crossed laser beams and the primary TPD Langmuir waves (LWs). The heated electron distribution function is, in all cases, bi-Maxwellian, with instantaneous hot-electron temperatures in the range 60-100 keV. The net hot-electron energy flux out of the system is a small fraction ({approx}1% to 2%) of the input laser intensity in these simulations. Scalings of the hot-electron temperature and suprathermal heat flux as functions of the laser intensity are obtained numerically from RPIC simulations. These simulations lead to the preliminary conclusion that Langmuir cavitation and collapse provide dissipation by producing suprathermal electrons, which stabilize the system in saturation and drive the LW spectrum to the small dissipation scales at the Landau cutoff. The Langmuir turbulence originates at an electron density 0.241 Multiplication-Sign the laser's critical density, where the crossed laser beams excite a 'triad' mode-a common forward LW plus a pair of backward LWs. Remnants of this 'triad' evolve in k-space and dominate the time-averaged energy spectrum. At times exceeding 10 ps, the excited Langmuir turbulence spreads toward lower densities. Comparisons of RPIC simulations with the extended Zakharov model are presented in appropriate regimes, and the necessary requirements for the validity of a quasi-linear Zakharov model (where the spatially averaged electron-velocity distribution is evolved) are verified by RPIC simulation results.

Vu, H. X. [University of California, San Diego, La Jolla, California 92093 (United States); DuBois, D. F. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Myatt, J. F. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2012-10-15T23:59:59.000Z

126

E-beam ionized channel guiding of an intense relativistic electron beam  

DOE Patents (OSTI)

An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path. 2 figs.

Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

1988-05-10T23:59:59.000Z

127

Laparoscopic tumor therapy using high energy electron ...  

The e-beam is transported through a laparoscopic tube proximate a target tumor for electron irradiation ... Biomass and Biofuels; Building Energy Efficiency;

128

High frequency limit for single-electron pumping operations  

E-Print Network (OSTI)

In this Letter, we study the transient electron transfer phenomena of single-electron devices with alternating external gate voltages. We obtain a high frequency limit for pumping electrons one at a time in single-electron devices. Also, we find that in general the electrical current is not proportional to the frequency of the external signals in the single-electron devices, due to the strong quantum coherence tunneling effect.

Chuan-Yu Lin; Wei-Min Zhang

2010-12-04T23:59:59.000Z

129

A high-intensity plasma-sputter heavy negative ion source  

SciTech Connect

A multicusp magnetic field plasma surface ion source, normally used for H/sup /minus//ion beam formation, has been modified for the generation of high-intensity, pulsed, heavy negative ion beams suitable for a variety of uses. To date, the source has been utilized to produce mA intensity pulsed beams of more than 24 species. A brief description of the source, and basic pulsed-mode operational data, (e.g., intensity versus cesium oven temperature, sputter probe voltage, and discharge pressure), are given. In addition, illustrative examples of intensity versus time and the mass distributions of ion beams extracted from a number of samples along with emittance data, are also presented. Preliminary results obtained during dc operation of the source under low discharge power conditions suggest that sources of this type may also be used to produce high-intensity (mA) dc beams. The results of these investigations are given, as well, and the technical issues that must be addressed for this mode of operation are discussed. 15 refs., 10 figs., 2 tabs.

Alton, G.D.; Mori, Y.; Takagi, A.; Ueno, A.; Fukumoto, S.

1989-01-01T23:59:59.000Z

130

The Evolution Towards Grids: Ten Years of High-Speed, Wide Area, Data Intensive Computing  

E-Print Network (OSTI)

1 The Evolution Towards Grids: Ten Years of High-Speed, Wide Area, Data Intensive Computing William aggregating and scheduling many resources. Data must be located and staged, cache and network capacity must and non-destructive imaging to supply real-time data to a remote, on-line, airframe structures expert who

131

The Edward teller medal lecture: High intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement. {copyright} {ital 1997 American Institute of Physics.}

Key, M.H. [Lawrence Livermore National Laboratory, Livermore, California94551 (United States)

1997-04-01T23:59:59.000Z

132

The Edward Teller medal lecture: High intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

Key, M. H. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1997-04-15T23:59:59.000Z

133

Edward Teller medal lecture: high intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

Key, M.H.

1997-06-02T23:59:59.000Z

134

Electron cloud effects on an intense ion beam in a four solenoid lattice  

E-Print Network (OSTI)

beam in a four solenoid lattice J.E. Coleman Department ofbeam in a two-solenoid lattice. Initial experiments showed aadded to the two-solenoid lattice in order to study electron

2008-01-01T23:59:59.000Z

135

Self-focusing of intense high frequency electromagnetic waves in a collisional magnetoactive plasma  

Science Conference Proceedings (OSTI)

The self-focusing of an intense electromagnetic beam in a collisional magnetoactive plasma has been investigated by the perturbation method. Considering the relativistic and ponderomotive nonlinearities and the first three terms of perturbation expansion for the electron density and velocity, the nonlinear wave equation is obtained. This wave equation is solved by applying the source dependent expansion method and the evolution of electromagnetic beam spot-size is discussed. It is shown that the laser spot-size decreases with increasing the collision frequency and external magnetic field strength.

Niknam, A. R.; Hashemzadeh, M. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of); Aliakbari, A.; Majedi, S. [Physics Department, Faculty of Science, Tafresh University, Tafresh (Iran, Islamic Republic of); Haji Mirzaei, F. [Physics Department, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of)

2011-11-15T23:59:59.000Z

136

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.  

DOE Green Energy (OSTI)

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

Nibur, Kevin A.

2010-11-01T23:59:59.000Z

137

High-order harmonic generation with Rydberg atoms by using an intense few-cycle pulse  

Science Conference Proceedings (OSTI)

We demonstrate that high-order harmonic generation (HHG) with both high cutoff frequency and high conversion efficiency can be realized by using a Rydberg atom in a few-cycle laser pulse. This is because a Rydberg state has a large electron orbital radius and small binding energy; therefore an electron in the Rydberg state can be ionized easily and accelerated directly toward the core under the interaction of a few-cycle laser pulse, leading to emission of harmonic photons. In this case, the tunneling process of the electron is not involved and, hence, the conversion efficiency and the cutoff frequency of harmonic generation can be higher than that predicted by the conventional three-step model.

Zhai Zhen; Fu Panming; Wang Bingbing [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Zhu Qiren [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Chen Jing [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Yan Zongchao [Department of Physics, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3 (Canada)

2011-04-15T23:59:59.000Z

138

Surface area generation and droplet size control in solvent extraction systems utilizing high intensity electric fields  

DOE Patents (OSTI)

A method and system for solvent extraction where droplets are shattered by a high intensity electric field. These shattered droplets form a plurality of smaller droplets which have a greater combined surface area than the original droplet. Dispersion, coalescence and phase separation are accomplished in one vessel through the use of the single pulsing high intensity electric field. Electric field conditions are chosen so that simultaneous dispersion and coalescence are taking place in the emulsion formed in the electric field. The electric field creates a large amount of interfacial surface area for solvent extraction when the droplet is disintegrated and is capable of controlling droplet size and thus droplet stability. These operations take place in the presence of a counter current flow of the continuous phase.

Scott, Timothy C. (Knoxville, TN); Wham, Robert M. (Oak Ridge, TN)

1988-01-01T23:59:59.000Z

139

Commissioning of the new high-intensity ultracold neutron source at the Paul Scherrer Institut  

E-Print Network (OSTI)

Commissioning of the new high-intensity ultracold neutron (UCN) source at the Paul Scherrer Institut (PSI) has started in 2009. The design goal of this new generation high intensity UCN source is to surpass by a factor of ~100 the current ultracold neutron densities available for fundamental physics research, with the greatest thrust coming from the search for a neutron electric dipole moment. The PSI UCN source is based on neutron production via proton induced lead spallation, followed by neutron thermalization in heavy water and neutron cooling in a solid deuterium crystal to cold and ultracold energies. A successful beam test with up to 2 mA proton beam on the spallation target was conducted recently. Most source components are installed, others being finally mounted. The installation is on the track for the first cool-down and UCN production in 2010.

Bernhard Lauss

2010-11-17T23:59:59.000Z

140

Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED.  

Science Conference Proceedings (OSTI)

We consider the possibility of experimental verification of vacuum e{sup +}e{sup -} pair creation at the focus of two counter-propagating optical laser beams with intensities 10{sup 20}-10{sup 22} W/cm{sup 2}, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10{sup 29} W/cm{sup 2} to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e{sup +} and e{sup -} distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e{sup +}e{sup -} annihilation into {gamma}-pairs and the refraction of a high-frequency probe laser beam by the produced e{sup +}e{sup -} plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for {mu}{sup +}{mu}{sup -} and {pi}{sup +}{pi}{sup -} pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as 'boosters' of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.

Blaschke, D. B.; Prozorkevich, A. V.; Roepke, G.; Roberts, C. D.; Schmidt, S. M.; Shkirmanov, D. S.; Smolyansky, S. A.; Physics; Univ. of Wroclaw; Joint Inst. for Nuclear Research; Univ. Rostock; Saratov State Univ.; Forschungszentrum Juelich GmbH

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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141

Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED  

E-Print Network (OSTI)

We consider the possibility of experimental verification of vacuum e^+e^- pair creation at the focus of two counter-propagating optical laser beams with intensities 10^{20}-10^{22} W/cm^2, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10^{29} W/cm^2 to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e^+ and e^- distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e^+e^- annihilation into gamma-pairs and the refraction of a high-frequency probe laser beam by the produced e^+e^- plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for \\mu^+\\mu^- and \\pi^+\\pi^- pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as ``boosters'' of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.

D. B. Blaschke; A. V. Prozorkevich; G. Roepke; C. D. Roberts; S. M. Schmidt; D. S. Shkirmanov; S. A. Smolyansky

2008-11-21T23:59:59.000Z

142

High temperature electronics and instrumentation seminar proceedings  

DOE Green Energy (OSTI)

This seminar was tailored to address the needs of the borehole logging industry and to stimulate the development and application of this technology, for logging geothermal, hot oil and gas, and steam injection wells. The technical sessions covered the following topics: hybrid circuits, electronic devices, transducers, cables and connectors, materials, mechanical tools and thermal protection. Thirty-eight papers are included. Separate entries were prepared for each one. (MHR)

Veneruso, A.F.; Arnold, C.; Simpson, R.S. (eds.)

1980-05-01T23:59:59.000Z

143

High temperature electronics application in well logging  

DOE Green Energy (OSTI)

Some limitations, problems, and needs are briefly reviewed for neutron logging tools used in high-temperature geothermal environments. (ACR)

Traeger, R.K.; Lysne, P.C.

1987-01-01T23:59:59.000Z

144

High intensity discharge 400-watt sodium ballast. Phase I. Final report  

SciTech Connect

The results of a research and development program directed toward design, test, and evaluation of energy efficient High Intensity Discharge (HID) Solid State 400-Watt Ballast lighting system are reported. Phase I of the project which was designed to modify the existing Datapower ballast to LBL configuration, measure performance characteristics, and compare efficiency with a core/coil ballast including energy loss analysis is covered. In addition, Datapower was tasked to build six (6) prototype 400-Watt High Pressure Sodium Ballasts for verification tests by an independent test facility and follow-on performance and life tests at LBL.

Felper, G.

1980-06-01T23:59:59.000Z

145

High-charge energetic electron bunch generated by intersecting laser pulses  

SciTech Connect

The interaction of two energetic electron bunches generated in the wakefields of two intense intersecting laser pulses in rarefied plasmas is investigated using particle-in-cell simulations. It is found that, with suitable intersection angle between the two laser pulses, the initially independent wakefield accelerated electron bunches can merged into a single one with high charge, energy, and narrow energy spread. The dynamics of the laser-pulse intersection and wake-bubble merging process is also investigated, and the crucial roles of the intersection angle are pointed out and analyzed.

Yang Lei; Deng Zhigang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wang, Xingang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062 (China)

2013-03-15T23:59:59.000Z

146

First high-temperature electronics products survey 2005.  

Science Conference Proceedings (OSTI)

On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

Normann, Randy Allen

2006-04-01T23:59:59.000Z

147

Narrow Energy Spread Protons and Ions from High-Intensity, High-Contrast Laser Solid Target Interactions  

Science Conference Proceedings (OSTI)

Recent simulations show that an idealized, high intensity, short pulse laser can generate quasi-monoenergetic proton beams with energies over 100 MeV in an interaction with a thin film. However, most short pulse laser facilities with sufficient intensity have difficulty controlling the nanosecond and picosecond contrast necessary to realize such a regime. Experiments were performed to investigate proton and ion acceleration from a high contrast, short pulse laser by employing dual plasma mirrors along with a deformable mirror at the HERCULES laser facility at the Center for Ultrafast Optical Sciences, University of Michigan. Plasma mirrors were characterized, allowing a 50% throughput with an intensity contrast increase of 105. The focal spot quality was also exceptional, showing a 1.1 micron full width at half maximum (FWHM) focal diameter. Experiments were done using temporally cleaned 30 TW, 32 fs pulses to achieve an intensity of up to 10{sup 21} Wcm{sup -2} on Si{sub 3}N{sub 4} and Mylar targets with thicknesses ranging 50 nm to 13 microns. Proton beams with energy spreads below 2 MeV were observed from all thicknesses, peaking with energies up to 10.3 MeV and an energy spread of 0.8 MeV. Similar narrow energy spreads were observed for oxygen, nitrogen, and carbon at the silicon nitride thickness of 50 nm with energies up to 24 MeV with an energy spread of 3 MeV, whereas the energy spread is greatly increased at a larger thickness. Maximum energies were confirmed with CR39 track detectors, while a Thomson ion spectrometer was used to gauge the monoenergetic nature of the beam.

Dollar, Franklin; Matsuoka, Takeshi; McGuffey, Christopher; Bulanov, Stepan S.; Chvykov, Vladimir; Kalintchenko, Galina; Thomas, Alec G. R.; Willingale, Louise; Yanovsky, Victor; Maksimchuk, Anatoly; Krushelnick, Karl [Center for Ultrafast Optical Science, Univ. Of Michigan, Ann Arbor, MI 48109 (United States); Davis, Jack; Petrov, George [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2010-11-04T23:59:59.000Z

148

Boron nitride substrates for high-quality graphene electronics  

E-Print Network (OSTI)

Boron nitride substrates for high-quality graphene electronics C. R. Dean1,2 *, A. F. Young3 , I and J. Hone2 * Graphene devices on standard SiO2 substrates are highly disor- dered, exhibiting report the fabrication and characterization of high-quality exfoliated mono- and bilayer graphene devices

Shepard, Kenneth

149

Millimeter-wave GaN high electron mobility transistors and their integration with silicon electronics  

E-Print Network (OSTI)

In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. ...

Chung, Jinwook W. (Jinwook Will)

2011-01-01T23:59:59.000Z

150

Time Integrated Soft X-ray Imaging in High Intensity Laser Experiments (thesis)  

Science Conference Proceedings (OSTI)

2009 marks a significant achievement and the dawn of a new era in high intensity laser research with the final commissioning of all 192 beams at the National Ignition Facility (NIF). NIF is a department of energy (DOE) funded project more than 10 years in the making located at the Lawrence Livermore National Laboratory (LLNL). The following research was done as one of many preliminary experiments done to prepare for these historic events. The primary focus of the experimental campaign this paper addresses is to test and develop a thermal x-radiation source using a short pulse laser. This data is hoped to provide information about the thermal transport mechanisms important in the development of prediction models in High Energy Density (HED) science. One of several diagnostics fielded was a soft x-ray imager (SXRI) which is detailed in this paper. The SXRI will be used to measure the relative size of the heated region and also the relative level of specific x-ray emissions among several shot and target configurations. The laser system used was the Titan laser located in the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). Titan uses the JLF Janus Nd:glass laser west frontend system with a Optical Parametric Chirped Pulse Amplification (OPCPA) in place of the nanosecond oscillator. The system is capable of producing laser intensities of over a petawatt with several tens of joules delivered in the beam.

Stafford, D

2009-06-01T23:59:59.000Z

151

System and method that suppresses intensity fluctuations for free space high-speed optical communication  

DOE Patents (OSTI)

A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

Berman, Gennady P. (Los Alamos, NM); Bishop, Alan R. (Los Alamos, NM); Nguyen, Dinh C. (Los Alamos, NM); Chernobrod, Boris M. (Santa Fe, NM); Gorshkov, Vacheslav N. (Kiev, UA)

2009-10-13T23:59:59.000Z

152

A Class Of Generalized Kapchinskij-Vladimirskij Solutions And Associated Envelope Equations For High-intensity Charged Particle Beams  

SciTech Connect

A class of generalized Kapchinskij-Vladimirskij solutions of the nonlinear Vlasov-Maxwell equations and the associated envelope equations for high-intensity beams in a periodic lattice is derived. It includes the classical Kapchinskij-Vladimirskij solution as a special case. For a given lattice, the distribution functions and the envelope equations are specified by eight free parameters. The class of solutions derived captures a wider range of dynamical envelope behavior for high-intensity beams, and thus provides a new theoretical tool to investigate the dynamics of high-intensity beams.

Hong Qin and Ronald C. Davidson

2012-04-25T23:59:59.000Z

153

Polymers with Tailored Electronic Structure for High Capacity Lithium  

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

Polymers with Tailored Electronic Structure for High Capacity Lithium Polymers with Tailored Electronic Structure for High Capacity Lithium Battery Electrodes Title Polymers with Tailored Electronic Structure for High Capacity Lithium Battery Electrodes Publication Type Journal Article Year of Publication 2011 Authors Liu, Gao, Shidi Xun, Nenad Vukmirovic, Xiangyun Song, Paul Olalde-Velasco, Honghe Zheng, Vince S. Battaglia, Linwang Wang, and Wanli Yang Journal Advanced Materials Volume 23 Start Page 4679 Issue 40 Pagination 4679 - 4683 Date Published 10/2011 Keywords binders, conducting polymers, density funcational theory, lithium batteries, X-ray spectroscopy Abstract A conductive polymer is developed for solving the long-standing volume change issue in lithium battery electrodes. A combination of synthesis, spectroscopy and simulation techniques tailors the electronic structure of the polymer to enable in situ lithium doping. Composite anodes based on this polymer and commercial Si particles exhibit 2100 mAh g-1 in Si after 650 cycles without any conductive additive.

154

High-intensity discharge (HID) solid-state ballast program: engineering development report. Phase II  

SciTech Connect

A high frequency (28 to 31/sup 0/K Hz) electronic current source (ballast) designed to drive a 200 watt 100 volt sodium vapor gas discharge lamp is described. A resonant switching power amplifier system utilizing a novel constant power feedback loop is employed to maintain the lamp input power constant within two percent via changes due to lamp aging etc. The lamp input power and therefore the light output is adjustable from 50 to 100 percent of rated power. A input (electronic filter) inverter, changes the 277 volts alternating voltage input to a regulated direct current (DC) voltage used to power the output stage. The inverter reflects, a essentially unity power factor load to the power input source at all times.

Carlson, R.S.

1983-12-01T23:59:59.000Z

155

Attaining and using extremely high intensities of solar energy with non-imaging concentrators  

SciTech Connect

Using the principles and techniques of non-imaging optics, solar concentrations that approach the theoretical maximum can be achieved. In this paper, the authors review recent progress in attaining, measuring, and using such ultrahigh solar fluxes. In particular, they review the design principles for optimized two-stage concentrators and solar furnaces and discuss the characteristics and properties of a variety of non-imaging secondaries which have been employed. These include Compound Parabolic Concentrators (CPC) type secondaries, Dielectric Totally Internally Reflecting Concentrators (DTIRC), and flow-line or {open_quotes}trumpet{close_quotes} concentrators. The usual design is a configuration where {phi}, the rim angle of the primary, is small, that is, corresponding to a system with a relatively large focal length to diameter (F/D) ratio. All three types of secondary are characterized by a design acceptance angle {phi}{sub a} which must be greater than or equal to {phi}. The design parameters and trade-offs for each of these systems including strategies for choice of particular secondary and degree of truncation, are presented. The authors review the calorimetric techniques used to measure these high intensities and describe a newly developed technique for {open_quotes}extracting{close_quotes} light from inside a high index medium. Finally they review a number of potential applications for highly concentrated solar energy and the current status of the associated technology. By making possible new and unique applications for intense solar flux, these techniques have opened a whole new frontier for research and development of potential economic uses of solar energy. 63 refs., 34 figs., 3 tabs.

Jenkins, D.; O`Gallagher, J.; Winston, R.

1997-12-31T23:59:59.000Z

156

Absolute intensity calibration of the Wendelstein 7-X high efficiency extreme ultraviolet overview spectrometer system  

Science Conference Proceedings (OSTI)

The new high effiency extreme ultraviolet overview spectrometer (HEXOS) system for the stellarator Wendelstein 7-X is now mounted for testing and adjustment at the tokamak experiment for technology oriented research (TEXTOR). One part of the testing phase was the intensity calibration of the two double spectrometers which in total cover a spectral range from 2.5 to 160.0 nm with overlap. This work presents the current intensity calibration curves for HEXOS and describes the method of calibration. The calibration was implemented with calibrated lines of a hollow cathode light source and the branching ratio technique. The hollow cathode light source provides calibrated lines from 16 up to 147 nm. We could extend the calibrated region in the spectrometers down to 2.8 nm by using the branching line pairs emitted by an uncalibrated pinch extreme ultraviolet light source as well as emission lines from boron and carbon in TEXTOR plasmas. In total HEXOS is calibrated from 2.8 up to 147 nm, which covers most of the observable wavelength region. The approximate density of carbon in the range of the minor radius from 18 to 35 cm in a TEXTOR plasma determined by simulating calibrated vacuum ultraviolet emission lines with a transport code was 5.5x10{sup 17} m{sup -3} which corresponds to a local carbon concentration of 2%.

Greiche, Albert; Biel, Wolfgang; Marchuk, Oleksandr [Institut fuer Energieforschung-Plasmaphysik, Forschungszentrum Juelich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Burhenn, Rainer [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany)

2008-09-15T23:59:59.000Z

157

A Lightweight, High-performance I/O Management Package for Data-intensive Computing  

Science Conference Proceedings (OSTI)

Our group has been working with ANL collaborators on the topic â??bridging the gap between parallel file system and local file systemâ?ť during the course of this project period. We visited Argonne National Lab -- Dr. Robert Rossâ??s group for one week in the past summer 2007. We looked over our current project progress and planned the activities for the incoming years 2008-09. The PI met Dr. Robert Ross several times such as HEC FSIO workshop 08, SCâ??08 and SCâ??10. We explored the opportunities to develop a production system by leveraging our current prototype to (SOGP+PVFS) a new PVFS version. We delivered SOGP+PVFS codes to ANL PVFS2 group in 2008.We also talked about exploring a potential project on developing new parallel programming models and runtime systems for data-intensive scalable computing (DISC). The methodology is to evolve MPI towards DISC by incorporating some functions of Google MapReduce parallel programming model. More recently, we are together exploring how to leverage existing works to perform (1) coordination/aggregation of local I/O operations prior to movement over the WAN, (2) efficient bulk data movement over the WAN, (3) latency hiding techniques for latency-intensive operations. Since 2009, we start applying Hadoop/MapReduce to some HEC applications with LANL scientists John Bent and Salman Habib. Another on-going work is to improve checkpoint performance at I/O forwarding Layer for the Road Runner super computer with James Nuetz and Gary Gridder at LANL. Two senior undergraduates from our research group did summer internships about high-performance file and storage system projects in LANL since 2008 for consecutive three years. Both of them are now pursuing Ph.D. degree in our group and will be 4th year in the PhD program in Fall 2011 and go to LANL to advance two above-mentioned works during this winter break. Since 2009, we have been collaborating with several computer scientists (Gary Grider, John bent, Parks Fields, James Nunez, Hsing-Bung Chen, etc) from HPC5 and James Ahrens from Advanced Computing Laboratory in Los Alamos National Laboratory. We hold a weekly conference and/or video meeting on advancing works at two fronts: the hardware/software infrastructure of building large-scale data intensive cluster and research publications. Our group members assist in constructing several onsite LANL data intensive clusters. Two parties have been developing software codes and research papers together using both sidesâ?? resources.

Wang, Jun

2011-06-22T23:59:59.000Z

158

Analysis of Intense Poleward Water Vapor Transports into High Latitudes of Western North America  

Science Conference Proceedings (OSTI)

Significant cool season precipitation along the western coast of North America is often associated with intense water vapor transport (IWVT) from the Pacific Ocean during favorable synoptic-scale flow regimes. These relatively narrow and intense ...

Alain Roberge; John R. Gyakum; Eyad H. Atallah

2009-12-01T23:59:59.000Z

159

Relativistic effects in the interaction of high intensity ultra-short laser pulse with collisional underdense plasma  

SciTech Connect

In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.

Abedi, Samira [Physics Department, North Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Abari, Mehdi Etehadi [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Shokri, Babak [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

2011-09-15T23:59:59.000Z

160

High-Intensity and High-Density Charge-Exchange Injection Studies into the CERN PS Booster at Intermediate Energies  

E-Print Network (OSTI)

For the high brilliance LHC ultimate beam and the high intensity CNGS beam, single batch injections into the CERN Proton Synchrotron (PS) will be used to increase the overall machine intensity compared with the present double batch injections. Charge-exchange injection into the PS Booster with a new linac at intermediate energies is thus examined. A key parameter to consider is the energy dependence of beam incoherent tune shifts at injection. Increasing the linac energy from the present 50 MeV to 160 MeV should yield a safer tune shift. For each PS Booster ring, a charge-exchange injection scheme is envisaged inside a proper straight section, redesigned with new bends to make a local bump and using the existing fast bump magnets for horizontal phase-space painting. ACCSIM simulations for charge-exchange injection at 160 MeV have been investigated for both LHC and CNGS beams. After optimizing the parameters that are used for the space charge tracking routines, the results of the simulations agree well with ex...

Martini, M

2004-01-01T23:59:59.000Z

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


161

Boron nitride substrates for high-quality graphene electronics  

E-Print Network (OSTI)

(right axis) versus gate voltage at B ÂĽ 14 T (solid line) and 8.5 T (dashed line) for monolayer grapheneBoron nitride substrates for high-quality graphene electronics C. R. Dean1,2 *, A. F. Young3 , I and J. Hone2 * Graphene devices on standard SiO2 substrates are highly disor- dered, exhibiting

Kim, Philip

162

Meson production in high-energy electron-nucleus scattering  

E-Print Network (OSTI)

Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering is now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus. The process takes place in the small-angle-Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

Göran Fäldt

2010-06-09T23:59:59.000Z

163

Industrial Application of High Combustion Intensity Systems and Energy Conservation Implications  

E-Print Network (OSTI)

In the past decade industrial combustion technology has been advanced through adaptations of the equipment operating with dramatically reduced excess air requirements and use of air preheat techniques. The importance of operating industrial combustion equipment at stoichiometric conditions is emphasized. The calculated fuel savings resulting from elimination of excess air and use of heat recovery air preheat are reviewed. Design parameters for the aerodynamic design and control of the combustion process are quantified for vortex stabilized systems. Design analyses of the fuel injectors used with gaseous, liquid and pulverized coal fuels are also presented. The resulting high intensity combustion systems evolved are illustrated with photographs of flames in actual installations and during equipment development testing. Attention to detail in equipment manufacture and proper field adjustment of combustion equipment is essential in achieving the dramatic fuel savings that are possible.

Williams, F. D. M.; Anderson, L. E.

1982-01-01T23:59:59.000Z

164

Design of a high-intensity RFQ for a possible LHC laser ion source  

E-Print Network (OSTI)

We have designed a 100 MHz RFQ to accelerate Pb25+ ions from 9.6 keV/u to 250 keV/u for the LHC ion program. We assume an input beam from a laser ion source with a total beam current of 90 mA, out of which 9 mA is Pb25+. The main challenge of the design is to match the tight longitudinal acceptance of the downstream Interdigital H structure while dealing with a high intensity beam composed of a variety of charge states. In this paper, we present a baseline setup optimized for nominal conditions, and show the sensitivity of the RFQ performance to varying input beam characteristics and rf parameters. Further studies will cover the compatibility of this design with an upgraded ECR source under investigation at CERN.

Hanke, K

2002-01-01T23:59:59.000Z

165

High-reliability high-efficiency electronic ballast  

SciTech Connect

This patent describes an electronic ballast adapted to connect with the AC voltage on an ordinary electric utility power line and to power a gas discharge lamp. The AC voltage is electrically referenced to ground, the ballast comprising: full-wave rectifier means connected with the AC voltage and operable to provide a DC output across a pair of DC output terminals; push-pull inverter means connected in series with an inductor means to form a series-combination, the series-combination being connected across the DC output terminals; the inverter means being operable to provide a current-limited substantially sinusoidal output voltage between a first output terminal and a second output terminal; the magnitude of the voltage existing between the first output terminal and ground being is substantially equal to that of the voltage existing between the second output terminal and ground, the phasing of the voltage existing between the first terminal and ground being substantially equal and opposite with respect to the phasing of the voltage existing between the second terminal and ground; the frequency of the output voltage is substantially higher than that of the AC voltage; connect means to permit connection of a gas discharge lamp across the output terminals; and safety means connected in circuit between the output terminals and the inverter means, operable to cause substantial reduction in the magnitude of the output voltage; in case the magnitude of current flowing out of the first output terminal is substantially different from that of the current flowing into the second output terminal, the safety means is then non-responsive to any current flowing in the power lines.

Nilssen, O.K.

1987-06-23T23:59:59.000Z

166

The theory and practice of high resolution scanning electron microscopy  

Science Conference Proceedings (OSTI)

Recent advances in instrumentation have produced the first commercial examples of what can justifiably be called High Resolution Scanning Electron Microscopes. The key components of such instruments are a cold field emission gun, a small-gap immersion probe-forming lens, and a clean dry-pumped vacuum. The performance of these microscopes is characterized by several major features including a spatial resolution, in secondary electron mode on solid specimens, which can exceed 1nm on a routine basis; an incident probe current density of the order of 10{sup 6} amps/cm{sup 2}; and the ability to maintain these levels of performance over an accelerating voltage range of from 1 to 30keV. This combination of high resolution, high probe current, low contamination and flexible electron-optical conditions provides many new opportunitites for the application of the SEM to materials science, physics, and the life sciences. 27 refs., 14 figs.

Joy, D.C. (Tennessee Univ., Knoxville, TN (USA) Oak Ridge National Lab., TN (USA))

1990-01-01T23:59:59.000Z

167

The LLNL/UCLA high gradient inverse free electron laser  

SciTech Connect

We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of > 200 MeV/m. We present the final design of the accelerator as well as the results of start-to-end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

Moody, J. T.; Musumeci, P.; Anderson, G.; Anderson, S.; Betts, S.; Fisher, S.; Gibson, D.; Tremaine, A.; Wu, S. [Department of Physics and Astronomy, UCLA, Los Angeles California, 90095 (United States); Lawrence Livermore National Laboratory (United States)

2012-12-21T23:59:59.000Z

168

High-intensity-discharger 400-W sodium ballast. Phase II. Final report  

SciTech Connect

A research and development program directed toward design, test, and evaluation of an energy efficient High Intensity Discharge (HID) Solid-State 400 Watt Ballast lighting system was undertaken. Under Phase I of the project, the existing ballast was modified, performance characteristics were measured, efficiency was compared with a core/coil ballast including energy loss analysis. Six (6) prototype 400 W High Pressure Sodium Ballasts were built, for verification tests by an independent test facility prior to follow-on performance and life tests. This report covers Phase II of the project which was designed to make test data comparisons on results received from the independent test laboratory, determine methods to increase ballast efficiency, determine the importance of power factors, conduct bulb life tests, perform specification review, performance versus cost analysis, investigate the ballast to determine compliance with new FCC requirement, and determine a line transient specification in respect to solid state ballasting. In addition, Phase II required reliability testing, a manufacturing test plan, a marketing study for solid-state ballast, and the manufacture and delivery of fifteen (15) demonstration ballast units to LBL. These requirements are discussed.

Felper, G.

1981-10-01T23:59:59.000Z

169

Preparation of diamond-like carbon and boron nitirde films by high-intensity pulsed ion beam deposition  

SciTech Connect

Intense ion beams (300-keV C{sup +}, O{sup +}, and H{sup +}, 20--30 kA, 50 to 400-ns pulsewidth, up to 0.3-Hz repetition rate) were used to prepare diamond-like carbon (DLC) and boron nitride (BN) films. Deposition rates of up to 25{plus_minus}5 nm/pulse were obtained with instantaneous rates exceeding 1 mm/s. Most films were uniform, light brown, translucent, and nonporous with some micron-size particulates. Raman and parallel electron energy loss spectroscopy indicated the presence of DLC. The films possessed favorable electron field-emission characteristics desirable for cold-cathode displays. Transmission electron microscopy (TEM) and transmission electron diffraction (TED) revealed that the C films contained diamond crystals with 25 to 125-nm grain size. BN films were composed of hexagonal, cubic and wurtzite phases.

Rej, D.J.; Davis, H.A. [Los Alamos National Lab., NM (United States); Remnev, G.E. [Tomsk Polytechnic Univ., Tomsk (Russian Federation). Nuclear Physics Institute.] [and others

1995-05-01T23:59:59.000Z

170

Electronically conductive ceramics for high temperature oxidizing environments  

DOE Patents (OSTI)

This invention pertains to a high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

Kucera, G.H.; Smith, J.L.; Sim, J.W.

1983-11-10T23:59:59.000Z

171

On the electron temperatures in high-metallicity HII regions  

E-Print Network (OSTI)

The electron temperatures of high-metallicity (12+log(O/H) > 8.2) HII regions have been studied. The empirical ff relations which express the nebular-to- auroral [OIII] line ratio Q_3,O (as well as the nebular-to-auroral [OII] line ratio Q_2,O, and the nebular-to-auroral [NII] line ratio Q_2,N) in terms of the nebular R_3 and R_2 line fluxes in spectra of high-metallicity HII regions are derived, and the electron temperatures t_3,O, t_2,O, and t_2,N in a number of extragalactic HII regions are also determined. Furthermore, the t_2 - t_3 diagram is discussed. It is found that there is a one-to-one correspondence between t_2 and t_3 electron temperatures for HII regions with a weak nebular R_3 lines (logR_ 0.5) do not follow this relation. A discrepancy between t_2,N and t_2,O temperatures is found, being the t_2,N temperatures systematically lower than t_2,O ones. The differences are small at low electron temperatures and increases with increasing electron temperatures up to 10% at t=1. The uncertainties in t...

Pilyugin, L S; Vílchez, J M; Cedres, B

2009-01-01T23:59:59.000Z

172

High-Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

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

Jay L. Hirshfield

2012-09-19T23:59:59.000Z

173

Electronic high frequency fluorescent ballasts (past, present and future)  

SciTech Connect

Based upon the years of development and manufacture as well as a documented three and one-half year life test the reliability of the electronic high frequency ballast concept has been established. There are several characteristics that can be used to assess a ballast's performance with respect to cost effectiveness, lamp life and power quality. The higher cost of the electronic ballast is due to the demand exceeding the supply. With more competition in an expanding market the price of ballasts will be significantly reduced. 4 refs.

Verderber, R.R.

1990-03-01T23:59:59.000Z

174

Sourcebook on high-temperature electronics and instrumentation  

DOE Green Energy (OSTI)

This sourcebook summarizes the high-temperature characteristics of a number of commercially available electronic components and materials required in geothermal well-logging instruments that must operate to 275/sup 0/C. The sourcebook is written to provide a starting place for instrument designers, who need to know the high-temperature electronic products that are available and the design and performance limitations of these products. The electronic component information given includes the standard repertoire of passive devices such as resistors, capacitors, and magnetics; the active devices and integrated circuits sections emphasize silicon semiconductor JFETs and CMOS circuits; and, to complete the electronics, interconnections and packaging of hybrid microelectronics are described. Thermal insulation and refrigeration alternatives are also presented in the sourcebook. Finally, instrument housing materials and high-temperature cables and cablehead connectors are listed. This information was compiled as part of the Geothermal Logging Instrumentation Development Program that Sandia National Laboratories conducted for the US Department of Energy's Divison of Geothermal Energy from 1976 to 1981.

Veneruso, A.F. (ed.)

1981-10-01T23:59:59.000Z

175

Sourcebook on high-temperature electronics and instrumentation  

SciTech Connect

This sourcebook summarizes the high-temperature characteristics of a number of commercially available electronic components and materials required in geothermal well-logging instruments that must operate to 275/sup 0/C. The sourcebook is written to provide a starting place for instrument designers, who need to know the high-temperature electronic products that are available and the design and performance limitations of these products. The electronic component information given includes the standard repertoire of passive devices such as resistors, capacitors, and magnetics; the active devices and integrated circuits sections emphasize silicon semiconductor JFETs and CMOS circuits; and, to complete the electronics, interconnections and packaging of hybrid microelectronics are described. Thermal insulation and refrigeration alternatives are also presented in the sourcebook. Finally, instrument housing materials and high-temperature cables and cablehead connectors are listed. This information was compiled as part of the Geothermal Logging Instrumentation Development Program that Sandia National Laboratories conducted for the US Department of Energy's Divison of Geothermal Energy from 1976 to 1981.

Veneruso, A.F. (ed.)

1981-10-01T23:59:59.000Z

176

High-Intensity Laser Interactions with Mass-Limited Solid Targets and Implications for Fast-Ignition Experiments on OMEGA EP  

Science Conference Proceedings (OSTI)

The modeling of petawatt laser-generated hot electrons in mass-limited solid-foil-target interactions at "relativistic" laser intensities is presented using copper targets and parameters motivated by recent experiments at the Rutherford Appleton Laboratory Petawatt and 100-TW facilities. Electron refluxing allows a unique determination of the laser-electron conversion efficiency and a test with simulations.

Myatt, J.; Theobald, W.; Delettrez, J.A.; Stoeckl, C.; Storm, M.; Sangster, T.C.; Maximov, A.V.; Short, R.W.

2007-03-23T23:59:59.000Z

177

Analytic fluid theory of beam spiraling in high-intensity cyclotrons  

E-Print Network (OSTI)

Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in isochronous cyclotrons in the nonrelativistic limit. With a multiscale analysis separating the time ...

Cerfon, A. J.

178

Development and applications of compact high-intensity lasers* G. Mourou+ and D. Umstadter  

E-Print Network (OSTI)

'ttnt*t' ' 't**Bd ' 'r'"& lOi 10'4 lOiS lo'! 10" Laser intensity (W/cm') 1 oio :0 109 z g lo8 3 N `ij 10

Umstadter, Donald

179

Generalized Kapchinskij-Vladimirskij Distribution and Envelope Equation for High-intensity Beams in a Coupled Transverse Focusing Lattice  

SciTech Connect

In an uncoupled lattice, the Kapchinskij-Vladimirskij (KV) distribution function first analyzed in 1959 is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high- intensity beams including self-fields in a self-consistent manner. The KV solution is generalized here to high-intensity beams in a coupled transverse lattice using the recently developed generalized Courant-Snyder invariant for coupled transverse dynamics. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space, determined by the generalized matrix envelope equation.

Hong Qin, Moses Chung, and Ronald C. Davidson

2009-11-20T23:59:59.000Z

180

Conceptual design of a high-intensity positron source for the Advanced Neutron Source  

SciTech Connect

The Advanced Neutron Source (ANS) is a planned new basic and applied research facility based on a powerful steady-state research reactor that provides neutrons for measurements and experiments in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The useful neutron flux will be at least five times more than is available in the world`s best existing reactor facility. Construction of the ANS provides a unique opportunity to build a positron spectroscopy facility (PSF) with very-high-intensity beams based on the radioactive decay of a positron-generating isotope. The estimated maximum beam current is 1000 to 5000 times higher than that available at the world`s best existing positron research facility. Such an improvement in beam capability, coupled with complementary detectors, will reduce experiment durations from months to less than one hour while simultaneously improving output resolution. This facility will remove the existing barriers to the routine use of positron-based analytical techniques and will be a giant step toward realization of the full potential of the application of positron spectroscopy to materials science. The ANS PSF is based on a batch cycle process using {sup 64}Cu isotope as the positron emitter and represents the status of the design at the end of last year. Recent work not included in this report, has led to a proposal for placing the laboratory space for the positron experiments outside the ANS containment; however, the design of the positron source is not changed by that relocation. Hydraulic and pneumatic flight tubes transport the source material between the reactor and the positron source where the beam is generated and conditioned. The beam is then transported through a beam pipe to one of several available detectors. The design presented here includes all systems necessary to support the positron source, but the beam pipe and detectors have not been addressed yet.

Hulett, L.D.; Eberle, C.C.

1994-12-01T23:59:59.000Z

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


181

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10{sup 15}-10{sup 17} W/cm{sup 2} and contrast ratio 10{sup 6} is studied. Red shift of a 'mirror' reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

Andreev, A. A.; Bayanov, V. I.; Vankov, A. B.; Kozlov, A. A.; Kurnin, I. V.; Platonov, K. Y.; Solovyev, N. A.; Chizhov, S. A.; Yashin, V. E. [Research Institute for Laser Physics, SC 'Vavilov State Optical Institute', 12, Birzhevaya line, St. Petersburg, 199034 (Russian Federation)

1998-02-20T23:59:59.000Z

182

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10 15 –10 17 ? W/cm 2 and contrast ratio 10 6 is studied. Red shift of a “mirror” reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

A. A. Andreev; V. I. Bayanov; A. B. Vankov; A. A. Kozlov; I. V. Kurnin; K. Y. Platonov; N. A. Solovyev; S. A. Chizhov; V. E. Yashin

1998-01-01T23:59:59.000Z

183

Experimental Estimate of Beam Loading and Minimum rf Voltage for Acceleration of High Intensity Beam in the Fermilab Booster  

E-Print Network (OSTI)

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Yang, X; Norem, J; Yang, Xi

2004-01-01T23:59:59.000Z

184

Experimental estimate of beam loading and minimum rf voltage for acceleration of high intensity beam in the Fermilab Booster  

SciTech Connect

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Xi Yang; Charles M Ankenbrandt and Jim Norem

2004-04-01T23:59:59.000Z

185

The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC  

Science Conference Proceedings (OSTI)

Electrons are ideal for treating shallow tumors and sparing adjacent normal tissue. Conventionally, electron beams are collimated by cut-outs that are time-consuming to make and difficult to adapt to tumor shape throughout the course of treatment. We propose that electron cut-outs can be replaced using photon multileaf collimator (MLC). Two major problems of this approach are that the scattering of electrons causes penumbra widening because of a large air gap, and available commercial treatment planning systems (TPSs) do not support MLC-collimated electron beams. In this study, these difficulties were overcome by (1) modeling electron beams collimated by photon MLC for a commercial TPS, and (2) developing a technique to reduce electron beam penumbra by adding low-energy intensity-modulated radiation therapy (IMRT) photons (4 MV). We used blocks to simulate MLC shielding in the TPS. Inverse planning was used to optimize boost photon beams. This technique was applied to a parotid and a central nervous system (CNS) clinical case. Combined photon and electron plans were compared with conventional plans and verified using ion chamber, film, and a 2D diode array. Our studies showed that the beam penumbra for mixed beams with 90 cm source to surface distance (SSD) is comparable with electron applicators and cut-outs at 100 cm SSD. Our mixed-beam technique yielded more uniform dose to the planning target volume and lower doses to various organs at risk for both parotid and CNS clinical cases. The plans were verified with measurements, with more than 95% points passing the gamma criteria of 5% in dose difference and 5 mm for distance to agreement. In conclusion, the study has demonstrated the feasibility and potential advantage of using photon MLC to collimate electron beams with boost photon IMRT fields.

Mosalaei, Homeira, E-mail: homeira.mosalaei@lhsc.on.ca [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); Karnas, Scott [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); University of Waterloo, Waterloo, Ontario (Canada); Shah, Sheel [University of Western Ontario, London, Ontario (Canada); Van Doodewaard, Sharon [McMaster University, Hamilton, Ontario (Canada); Foster, Tim [University of Western Ontario, London, Ontario (Canada); Chen, Jeff [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); University of Waterloo, Waterloo, Ontario (Canada)

2012-04-01T23:59:59.000Z

186

SECONDARY ELECTRON TRAJECTORIES IN HIGH-GRADIENT VACUUM INSULATORS WITH FAST HIGH-VOLTAGE PULSES  

Science Conference Proceedings (OSTI)

Vacuum insulators composed of alternating layers of metal and dielectric, known as high-gradient insulators (HGIs), have been shown to withstand higher electric fields than conventional insulators. Primary or secondary electrons (emitted from the insulator surface) can be deflected by magnetic fields from external sources, the high-current electron beam, the conduction current in the transmission line, or the displacement current in the insulator. These electrons are deflected either toward or away from the insulator surface and this affects the performance of the vacuum insulator. This paper shows the effects of displacement current from short voltage pulses on the performance of high gradient insulators. Generally, vacuum insulator failure is due to surface flashover, initiated by electrons emitted from a triple junction. These electrons strike the insulator surface thus producing secondary electrons, and can lead to a subsequent electron cascade along the surface. The displacement current in the insulator can deflect electrons either toward or away from the insulator surface, and affects the performance of the vacuum insulator when the insulator is subjected to a fast high-voltage pulse. Vacuum insulators composed of alternating layers of metal and dielectric, known as high-gradient insulators (HGIs), have been shown to withstand higher electric fields than conventional insulators. HGIs, being tolerant of the direct view of high-current electron and ion beams, and having desirable RF properties for accelerators, are a key enabling technology for the dielectric-wall accelerators (DWA) being developed at Lawrence Livermore National Laboratory (LLNL). Characteristically, insulator surface breakdown thresholds go up as the applied voltage pulse width decreases. To attain the highest accelerating gradient in the DWA, short accelerating voltage pulses are only applied locally, along the HGI accelerator tube, in sync with the charged particle bunch, and the effects of displacement current on trajectories of electrons emitted from HGI surface are particularly interesting. This paper presents simulated electron trajectories experiencing either constant or short-duration applied voltage pulses. Comparisons of these trajectories clearly indicate the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process for HGIs.

Chen, Y; Blackfield, D; Nelson, S D; Poole, B

2010-04-21T23:59:59.000Z

187

Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma  

DOE Green Energy (OSTI)

This volume is a direct continuation of Volume 1. Included are chapters 5 and 6 which deal with the trapping and confinement of electron rings in preionized media, neutral gases, and plasma.

Smith, A.C. Jr.

1977-04-25T23:59:59.000Z

188

High Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

A new type of switch for modulation of the Q-factor of a multi-mode storage resonator in a high-power active microwave pulse compressor is described. The operating principle of the switch is based on a sharp increase in the TE{sub 02{yields}}TE{sub 01} coupling coefficient, when an electron beam is injected into the switch cavity. The switch was tested at low power level in a compressor operated at X-band. A power gain of 19-20 in the compressed pulse with pulse duration of 40-50 ns was achieved. The proposed switch shows good prospects for use in high-power active pulse compressors.

Ivanov, O. A.; Vikharev, A. L. [Institute of Applied Physics RAS, Nizhny Novgorod, 603600 (Russian Federation); Omega-P, Inc., New Haven, Connecticut 06510 (United States); Isaev, V. A.; Lobaev, M. A. [Institute of Applied Physics RAS, Nizhny Novgorod, 603600 (Russian Federation); Hirshfield, J. L. [Omega-P, Inc., New Haven, Connecticut 06510 (United States); Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)

2010-11-04T23:59:59.000Z

189

Electronic phase diagram of high temperature copper oxide superconductors.  

SciTech Connect

In order to understand the origin of high-temperature superconductivity in copper oxides, we must understand the normal state from which it emerges. Here, we examine the evolution of the normal state electronic excitations with temperature and carrier concentration in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} using angle-resolved photoemission. In contrast to conventional superconductors, where there is a single temperature scale T{sub c} separating the normal from the superconducting state, the high-temperature superconductors exhibit two additional temperature scales. One is the pseudogap scale T*, below which electronic excitations exhibit an energy gap. The second is the coherence scale T{sub coh}, below which sharp spectral features appear due to increased lifetime of the excitations. We find that T* and T{sub coh} are strongly doping dependent and cross each other near optimal doping. Thus the highest superconducting T{sub c} emerges from an unusual normal state that is characterized by coherent excitations with an energy gap.

Chatterjee, U.; Ai, D.; Zhao, J.; Rosenkranz, S.; Kaminski, A.; Raffy, H.; Li, Z. Z.; Kadowaki, K.; Randeria, M.; Norman, M. R.; Campuzano, J. C. (Materials Science Division); (Univ. of Illinois at Chicago); (Iowa State Univ.); (Univ. Paris-Sud); (Univ. of Tsukuba); (Ohio State Univ.)

2011-06-07T23:59:59.000Z

190

High intensity uranium beams from the superHILAC and the bevatron: final report  

Science Conference Proceedings (OSTI)

The two injectors formerly used at the SuperHILAC were a 750-kV air-insulated Cockcroft-Walton (EVE) and a 2.5-MV pressurized HV multiplier (ADAM). The EVE injector can deliver adequate intensities of ions up to mass 40 (argon). The ADAM injector can accelerate ions with lower charge-to-mass ratios, and they can produce beams of heavier ions. The intensity of these beams decreases as the mass number increases, with the lowest practical intensity being achieved with lead beams. Experience with the two existing injectors provided substantial help in defining the general requirements for a new injector which would provide ample beams above mass 40. The requirements for acceptance by the first tank of the SuperHILAC are a particle velocity ..beta.. = 0.0154 (corresponding to an energy of 113 keV/amu) and a charge-to-mass ratio of 0.046 or larger. Present ion source performance dictates an air-insulated Cockcroft-Walton as a pre-accelerator because of its easy accessibility and its good overall reliability. The low charge state ions then receive further acceleration and, if necessary, subsequent stripping to the required charge state before injection into the SuperHILAC. A low-beta linac of the Widereoe type has been built to perform this acceleration. The injector system described consists of a Cockcroft-Walton pre-injector, injection beam lines and isotope analysis, a low-velocity linear accelerator, and SuperHILAC control center modifications.

Not Available

1982-03-01T23:59:59.000Z

191

Manifestation of quantum chaos on scattering techniques: application to low-energy and photo-electron diffraction intensities  

E-Print Network (OSTI)

Intensities of LEED and PED are analyzed from a statistical point of view. The probability distribution is compared with a Porter-Thomas law, characteristic of a chaotic quantum system. The agreement obtained is understood in terms of analogies between simple models and Berry's conjecture for a typical wavefunction of a chaotic system. The consequences of this behaviour on surface structural analysis are qualitatively discussed by looking at the behaviour of standard correlation factors.

P. L. de Andres; J. A. Vergés

1997-10-08T23:59:59.000Z

192

Investigating physical and chemical changes in high-k gate stacks using nanoanalytical electron microscopy  

Science Conference Proceedings (OSTI)

The thermal budget involved in processing high-k gate stacks can cause undesirable physical and chemical changes which limit device performance. The transmission electron microscope and associated analytical techniques provide a way of investigating ... Keywords: Electron energy loss near edge structure, Electron energy loss spectroscopy, High-k dielectrics, Nanoanalytical electron microscopy

A. J. Craven; M. MacKenzie; D. W. McComb; F. T. Docherty

2005-06-01T23:59:59.000Z

193

Intense multimicrojoule high-order harmonics generated from neutral atoms of In{sub 2}O{sub 3} nanoparticles  

Science Conference Proceedings (OSTI)

We studied high-order harmonic generation from plasma that contains an abundance of indium oxide nanoparticles. We found that harmonics from nanoparticle-containing plasma are considerably more intense than from plasma produced on the In{sub 2}O{sub 3} bulk target, with high-order harmonic energy ranging from 6 {mu}J (for the ninth harmonic) to 1 {mu}J (for the 17th harmonic) in the former case. The harmonic cutoff from nanoparticles was at the 21st order, which is lower than that observed using indium oxide solid target. By comparing the harmonic spectra obtained from solid and nanoparticle indium oxide targets, we concluded that intense harmonics in the latter case are dominantly generated from neutral atoms of the In{sub 2}O{sub 3} nanoparticles.

Elouga Bom, L. B.; Abdul-Hadi, J.; Vidal, F.; Ozaki, T. [Centre Energie, Materiaux et Telecommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Ganeev, R. A. [Centre Energie, Materiaux et Telecommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Scientific Association Akadempribor, Uzbekistan Academy of Sciences, Akademgorodok, Tashkent 100125 (Uzbekistan)

2009-03-16T23:59:59.000Z

194

X-ray Methods in High-Intensity Discharges and Metal-Halide Lamps: X-ray Induced Fluorescence  

SciTech Connect

We describe the use of x-ray induced fluorescence to study metal-halide high-intensity discharge lamps and to measure equilibrium vapor pressures of metal-halide salts. The physical principles of metal-halide lamps, relevant aspects of x-ray-atom interactions, the experimental method using synchrotron radiation, and x-ray induced fluorescence measurements relevant to metal-halide lamps are covered.

Curry, John J.; Lapatovich, Walter P.; Henins, Albert (NIST)

2011-12-09T23:59:59.000Z

195

Production of high-density high-temperature plasma by collapsing small solid-density plasma shell with two ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Three-dimensional particle-in-cell simulations show that the anisotropic collapse of a plasma microshell by impact of two oppositely directed intense laser pulses can create at the center of the shell cavity a submicron-sized plasma of high density and temperature suitable for generating fusion neutrons.

Xu, H. [National Laboratory for Parallel and Distributed Processing, School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, Bochum D-44780 (Germany); Wong, A. Y. [Department of Physics, University of California, Los Angeles, California 90095 (United States); Sheng, Z. M.; Zhang, J. [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)

2012-04-02T23:59:59.000Z

196

Atomic gas temperature in a nonequilibrium high-intensity discharge lamp determined from the red wing of the resonance mercury line 254 nm  

Science Conference Proceedings (OSTI)

For developing low-wattage high intensity discharge (HID) lamps, a better understanding of the relatively unexplored nonequilibrium phenomena is essential. This needs interpretation of diagnostic results by methods free from equilibrium assumptions. In this paper, the atomic temperature is determined from the simulation of a quasistatic broadened resonance line by distinguishing between atomic temperature and excitation temperature in the equation of radiative transfer. The proposed method is applied to the red wing of the resonance mercury line 254 nm emitted from a HID lamp working on ac. The experimental results show severe deviation from local thermodynamic equilibrium. More than one thousand degrees difference was obtained between atomic and electron temperatures at the maximum current phase.

Drakakis, E. [Technological Educational Institute, Department of Electrical Engineering, 71004 Heraklion (Greece); Karabourniotis, D. [Institute of Plasma Physics, Department of Physics, University of Crete, 71003 Heraklion (Greece)

2012-09-01T23:59:59.000Z

197

Sensitivity to Dark Energy candidates by searching for four-wave mixing of high-intensity lasers in the vacuum  

E-Print Network (OSTI)

Theoretical challenges to understand Dark Matter and Dark Energy suggest the existence of low-mass and weakly coupling fields in the universe. The quasi-parallel photon-photon collision system (QPS) can provide chances to probe the resonant production of these light dark fields and the induced decay by the coherent nature of laser fields simultaneously. By focusing high-intensity lasers with different colors in the vacuum, new colors emerge as the signature of the interaction. Because four photons in the initial and final states interplay via the dark field exchange, this process is analogous to four-wave mixing in quantum optics, where the frequency sum and difference among the incident three waves generate the fourth wave with a new frequency via the nonlinear property of crystals. The interaction rate of the four-wave mixing process has the cubic dependence on the intensity of each wave. Therefore, if high-intensity laser fields are given, the sensitivity to the weakly coupling of dark fields to photons rapidly increases over the wide mass range below sub-eV. Based on the experimentally measurable photon energies and the linear polarization states, we formulate the relation between the accessible mass-coupling domains and the high-intensity laser parameters, where the effects of the finite spectrum width of pulse lasers are taken into account. The expected sensitivity suggests that we have a potential to explore interactions at the Super-Planckian coupling strength in the sub-eV mass range, if the cutting-edge laser technologies are properly combined.

Kensuke Homma

2012-11-09T23:59:59.000Z

198

Multiplication of high-energy electrons in irradiated materials studied using the Boltzmann kinetic equation  

SciTech Connect

Processes involved in the formation of electron collision cascades created by nonrelativistic high-energy electrons, which can develop in materials exposed to electron and gamma radiation fluxes, have been considered. The problem is solved using the Boltzmann kinetic equation for high-energy electrons moving in a medium. A model scattering indicatrix is constructed for this equation with an arbitrary potential of interaction between colliding particles. Using this scattering indicatrix, the distribution of the particle energies is obtained. Based on this energy distribution (with an arbitrary interparticle interaction potential), a cascade function is found that describes the multiplication of knock-out electrons (electron cascade) generated when a high-energy electron with a certain energy is scattered on the electron subsystem of the irradiated material. The cascade function has been calculated for the Coulomb potential of the interaction between a high-energy electron and atomic-shell electrons.

Ryazanov, A. I., E-mail: ryazanoff@eomail.ru; Mogilyuk, T. I.; Semenov, E. V. [National Research Centre Kurchatov Institute (Russian Federation)

2012-04-15T23:59:59.000Z

199

Design Considerations for High Energy Electron -- Positron Storage Rings  

DOE R&D Accomplishments (OSTI)

High energy electron-positron storage rings give a way of making a new attack on the most important problems of elementary particle physics. All of us who have worked in the storage ring field designing, building, or using storage rings know this. The importance of that part of storage ring work concerning tests of quantum electrodynamics and mu meson physics is also generally appreciated by the larger physics community. However, I do not think that most of the physicists working tin the elementary particle physics field realize the importance of the contribution that storage ring experiments can make to our understanding of the strongly interacting particles. I would therefore like to spend the next few minutes discussing the sort of things that one can do with storage rings in the strongly interacting particle field.

Richter, B.

1966-11-00T23:59:59.000Z

200

Experimental investigation of electron multipactor discharges at very high frequency  

E-Print Network (OSTI)

Multipactor discharges are a resonant condition in which electrons impact a surface in phase with an alternating electric field. The discharge is sustained by electron multiplication from secondary emission. As motivation, ...

Graves, Timothy P. (Timothy Paul)

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity electron" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


201

Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies  

E-Print Network (OSTI)

The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyv\\"askyl\\"a, has been supplied with a new cyclotron which will provide protons of the order of 100 {\\mu}A with up to 30 MeV energy, or deuterons with half the energy and intensity. This makes it an ideal place for measurements of neutron-induced fission products from various actinides, in view of proposed future nuclear fuel cycles. The groups at Uppsala University and University of Jyv\\"askyl\\"a are working on the design of a neutron converter that will be used as neutron source in fission yield studies. The design is based on simulations with Monte Carlo codes and a benchmark measurement that was recently performed at The Svedberg Laboratory in Uppsala. In order to obtain a competitive count rate the fission targets will be placed very close to the neutron converter. The goal is to have a flexible design that will enable the use of neutron fields with different energy distributions. In the present paper, some considerations for the design of the neutron converter will be discussed, together with different scenarios for which fission targets and neutron energies to focus on.

M. Lantz; D. Gorelov; A. Jokinen; V. S. Kolhinen; A. Mattera; H. Penttilä; S. Pomp; V. Rakopoulos; S. Rinta-Antila; A. Solders

2013-04-09T23:59:59.000Z

202

High intensity discharge lamp self-adjusting ballast system sensitive to the radiant energy or heat of the lamp  

SciTech Connect

This patent describes a self-adjusting ballast system for mercury vapor, high intensity discharge lamps having outputs of 100 watts or greater, comprising: a direct current source; a lamp circuit containing a high intensity discharge lamp; sensing means for sensing the radiant energy output of the lamp; a pulse width modulator which, in response to the output of the sensing means, varies the width of the pulses that power the lamp during warm-up of the lamp; a high frequency oscillator; a DC to AC converter that converts current from the direct source to pulses of alternating current for powering the lamp, the converter comprising: at least one switch for gating current to the lamp; a switch control means, responsive to the high frequency oscillator, for controlling the switch and controlling the frequency of the alternating current pulses that power the lamp; current sensing means for sensing the current being supplied to the lamp; and current control means for limiting the current through the lamp to a predetermined safe level when the current sensed by the current sensing means exceeds a reference value.

Kuhnel, D.S.; Ottenstein, S.A.

1987-07-21T23:59:59.000Z

203

Thermal imaging diagnostics of high-current electron beams  

SciTech Connect

The thermal imaging diagnostics of measuring pulsed electron beam energy density is presented. It provides control of the electron energy spectrum and a measure of the density distribution of the electron beam cross section, the spatial distribution of electrons with energies in the selected range, and the total energy of the electron beam. The diagnostics is based on the thermal imager registration of the imaging electron beam thermal print in a material with low bulk density and low thermal conductivity. Testing of the thermal imaging diagnostics has been conducted on a pulsed electron accelerator TEU-500. The energy of the electrons was 300-500 keV, the density of the electron current was 0.1-0.4 kA/cm{sup 2}, the duration of the pulse (at half-height) was 60 ns, and the energy in the pulse was up to 100 J. To register the thermal print, a thermal imager Fluke-Ti10 was used. Testing showed that the sensitivity of a typical thermal imager provides the registration of a pulsed electron beam heat pattern within one pulse with energy density over 0.1 J/cm{sup 2} (or with current density over 10 A/cm{sup 2}, pulse duration of 60 ns and electron energy of 400 keV) with the spatial resolution of 0.9-1 mm. In contrast to the method of using radiosensitive (dosimetric) materials, thermal imaging diagnostics does not require either expensive consumables, or plenty of processing time.

Pushkarev, A.; Kholodnaya, G.; Sazonov, R.; Ponomarev, D. [Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

2012-10-15T23:59:59.000Z

204

Plume splitting and rebounding in a high-intensity CO{sub 2} laser induced air plasma  

Science Conference Proceedings (OSTI)

The dynamics of plasma plume formed by high-intensity CO{sub 2} laser induced breakdown of air at atmospheric pressure is investigated. The laser wavelength is 10.6 {mu}m. Measurements were made using 3 ns gated fast photography as well as space and time resolved optical emission spectroscopy. The behavior of the plasma plume was studied with a laser energy of 3 J and 10 J. The results show that the evolution of the plasma plume is very complicated. The splitting and rebounding of the plasma plume is observed to occur early in the plumes history.

Chen Anmin; Jiang Yuanfei; Liu Hang; Jin Mingxing; Ding Dajun [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

2012-07-15T23:59:59.000Z

205

High-efficiency free-electron laser results  

Science Conference Proceedings (OSTI)

Results obtained with a tapered-wiggler free-electron laser demonstrate the concepts proposed by Morton for enhanced efficiency and show deceleration of electrons by as much as 7%, and extraction of more than 3% of the total electron-beam energy as laser energy when the laser is operated as an amplifier. The experiment is presently being reconfigured to examine its performance as a laser oscillator.

Boyer, K.; Baru, C.A.; Newnam, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.; Young, L.M.

1983-01-01T23:59:59.000Z

206

High Contrast Hollow-Cone Dark Field Transmission Electron ...  

Science Conference Proceedings (OSTI)

For nanocrystalline materials, the scale of grain size necessitates the use of transmission electron microscopy (TEM) for quantification. Given the complex ...

207

Oxide Target Designs for High Primary Beam Intensities for Future Radioactive Ion Beam Facilities  

SciTech Connect

Oxide targets used nowadays in ISOL facilities can only accommodate up to a few kW incoming beam power because of the targets' moderate operation temperatures and their low thermal conductivities. A generic design to accommodate a 100 kW, 1 GeV proton beam, used as baseline parameters in the ongoing EURISOL-DS project, along with the numerical and experimental tools required for its validation, are reported here. We provide some details on these high-power composite oxide-refractory metal targets and on the proposed arrangement in several sub-units merging into a single ion source.

Stora, T.; Bouquerel, E.; Bruno, L.; Catherall, R.; Fernandes, S.; Kasprowicz, P.; Lettry, J.; Marzari, S.; Noah, E.; Penescu, L.; Wilfinger, R. [AB Department, CERN, CH-1211 Geneva 23 (Switzerland); Singh, B. S. Nara [Department of Physics, University of York, York, Y10 5DD (United Kingdom)

2009-03-10T23:59:59.000Z

208

Contribution to the numerical study of turbulence in high intensity discharge lamps  

SciTech Connect

We present in this paper a comparison between results obtained with a laminar and turbulent models for high-pressure mercury arc. The two models are based on the resolution of bidimensional time-dependent equations by a semi-implicit finite-element code. The numerical computation of turbulent model is solved with large eddy simulation model; this approach takes into account the various scales of turbulence by a filtering method on each scale. The results show the quantitative influence of turbulence on the flow fields and also the difference between laminar and turbulent effects on the dynamic thermal behaviour and on the characteristics of the discharge.

Kaziz, S.; Ben Ahmed, R.; Helali, H.; Gazzah, H.; Charrada, K. [Unite d'Etude des Milieux Ionises et Reactifs, IPEIM, 5019 route de Kairouan Monastir (Tunisia)

2011-07-15T23:59:59.000Z

209

Interaction of relativistic electron beams with high Z plasmas  

SciTech Connect

A set of relativistic multigroup diffusion equations was derived for the study of electron beam--target interactions. Included are transport, Coulomb collisions, electric and magnetic fields, bremsstrahlung, and hydrodynamic motion of the background plasma. LASNEX, the Laser-Fusion code, is being modified to include these equations and will be used for modeling electron beam fusion. (auth)

Kershaw, D.S.

1975-10-27T23:59:59.000Z

210

LambdaStation: Exploiting Advance Networks In Data Intensive High Energy Physics Applications  

SciTech Connect

Lambda Station software implements selective, dynamic, secure path control between local storage & analysis facilities, and high bandwidth, wide-area networks (WANs). It is intended to facilitate use of desirable, alternate wide area network paths which may only be intermittently available, or subject to policies that restrict usage to specified traffic. Lambda Station clients gain awareness of potential alternate network paths via Clarens-based web services, including path characteristics such as bandwidth and availability. If alternate path setup is requested and granted, Lambda Station will configure the local network infrastructure to properly forward designated data flows via the alternate path. A fully functional implementation of Lambda Station, capable of dynamic alternate WAN path setup and teardown, has been successfully developed. A limited Lambda Station-awareness capability within the Storage Resource Manager (SRM) product has been developed. Lambda Station has been successfully tested in a number of venues, including Super Computing 2008. LambdaStation software, developed by the Fermilab team, enables dynamic allocation of alternate network paths for high impact traffic and to forward designated flows across LAN. It negotiates with reservation and provisioning systems of WAN control planes, be it based on SONET channels, demand tunnels, or dynamic circuit networks. It creates End-To-End circuit between single hosts, computer farms or networks with predictable performance characteristics, preserving QoS if supported in LAN and WAN and tied security policy allowing only specific traffic to be forwarded or received through created path. Lambda Station project also explores Network Awareness capabilities.

Harvey B. Newman

2009-09-11T23:59:59.000Z

211

Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species  

DOE Patents (OSTI)

Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

Cross, Jon B. (Santa Fe, NM); Cremers, David A. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

212

Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species  

DOE Patents (OSTI)

Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

Cross, J.B.; Cremers, D.A.

1986-01-10T23:59:59.000Z

213

High-intensity ion sources for accelerators with emphasis on H-beam formation and transport  

SciTech Connect

This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as d. c. discharge- and rf-driven multicusp sources. Penning-type and ECR-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber-. and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed. ionization mechanism, beam formation and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

Keller, Roderich [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

214

Design features of high-intensity medium-energy superconducting heavy-ion Linac.  

DOE Green Energy (OSTI)

The proposed Rare Isotope Accelerator (RIA) requires the construction of a cw 1.4 GV superconducting (SC) linac that is capable of producing 400 kW beams of all ions from protons at 900 MeV to uranium at 400 MeV/u. The design of such a linac was outlined at the previous Linac conference. This linac will accelerate multiple-charge-states (multi-q) of the heaviest ion beams, for which the beam current is limited by ion-source performance. The linac consists of two different types of accelerating and focusing lattice: for uranium below {approx}85 MeV/u the focusing is provided by SC solenoids installed in cryostats with the SC resonators while in the high-beta section the focusing elements are located outside of the cryostats. A detailed design has been developed for the focusing-accelerating lattice of the linac. Beam dynamics studies have been performed with the goal of optimization of the linac structure in order to reduce a possible effective emittance growth of the multi-q uranium beam. A wide tuning range of the accelerating and focusing fields is required for acceleration of the variety of ions with different charge-to-mass ratios to the highest possible energy in single charge state mode. The focusing must be retuned for different ion masses to avoid resonance coupling between the transverse and longitudinal motions. Any visible impact of this coupling on the formation of beam halo must be avoided due to the high beam power.

Ostroumov, P. N.

2002-09-20T23:59:59.000Z

215

Using high-intensity laser-generated energetic protons to radiograph directly driven implosions  

Science Conference Proceedings (OSTI)

The recent development of petawatt-class lasers with kilojoule-picosecond pulses, such as OMEGA EP [L. Waxer et al., Opt. Photonics News 16, 30 (2005)], provides a new diagnostic capability to study inertial-confinement-fusion (ICF) and high-energy-density (HED) plasmas. Specifically, petawatt OMEGA EP pulses have been used to backlight OMEGA implosions with energetic proton beams generated through the target normal sheath acceleration (TNSA) mechanism. This allows time-resolved studies of the mass distribution and electromagnetic field structures in ICF and HED plasmas. This principle has been previously demonstrated using Vulcan to backlight six-beam implosions [A. J. Mackinnon et al., Phys. Rev. Lett. 97, 045001 (2006)]. The TNSA proton backlighter offers better spatial and temporal resolution but poorer spatial uniformity and energy resolution than previous D{sup 3}He fusion-based techniques [C. Li et al., Rev. Sci. Instrum. 77, 10E725 (2006)]. A target and the experimental design technique to mitigate potential problems in using TNSA backlighting to study full-energy implosions is discussed. The first proton radiographs of 60-beam spherical OMEGA implosions using the techniques discussed in this paper are presented. Sample radiographs and suggestions for troubleshooting failed radiography shots using TNSA backlighting are given, and future applications of this technique at OMEGA and the NIF are discussed.

Zylstra, A. B.; Li, C. K.; Rinderknecht, H. G.; Seguin, F. H.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C.; Meyerhofer, D. D.; Nilson, P.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Le Pape, S.; Mackinnon, A.; Patel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-01-15T23:59:59.000Z

216

A Photo-Stimulated Low Electron Temperature High Current Diamond Film Field  

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

A Photo-Stimulated Low Electron Temperature High Current Diamond A Photo-Stimulated Low Electron Temperature High Current Diamond Film Field Emission Cathode A Photo-Stimulated Low Electron Temperature High Current Diamond Film Field Emission Cathode Nanostructure diamond cathodes can operate at relatively moderate vacuum pressures due to the inert surface/vacuum interface. September 27, 2013 A Photo-Stimulated Low Electron Temperature High Current Diamond Film Field Emission Cathode Researchers at LANL have developed a novel, ultra-high-quality, robust electron source, which uses nanostructured polycrystalline diamond in a matrix with single-walled carbon nanotubes (SWCNs). Available for thumbnail of Feynman Center (505) 665-9090 Email A Photo-Stimulated Low Electron Temperature High Current Diamond Film Field Emission Cathode

217

High density of electronic excitation in nanometric scale: transformation of the matter.  

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

density density of electronic excitation in nanometric scale: transformation of the matter. Marcel Toulemonde CIMAP, Caen, France Within the several possibilities of producing high electronic excitation, swift heavy ions allow to create a high electronic density in nanometer scale. The energy deposited on the electrons along the ion path comes down to the lattice and transform the matter in a cylinder of around 10 nm in diameter (figure on left) After a review of selected experimental results concerning insulating materials, a transient thermal process will be developed to quantify the track size. In this model, the energy given to the electrons relaxes to the lattice atoms via the electron-phonon interaction. When considering the input parameters in this model, the main one will be the electron-phonon mean free path that defines the length of energy that diffuses on the electrons prior

218

Development of a high average current polarized electron source with long cathode operational lifetime  

SciTech Connect

Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

2007-02-01T23:59:59.000Z

219

HIGH LATITUDE ULYSSES OBSERVATIONS OF THE H/HE INTENSITY RATIO UNDER SOLAR MINIMUM AND SOLAR MAXIMUM CONDITIONS  

DOE Green Energy (OSTI)

We analyze measurements of the 0.5-1.0 MeV/nucleon H/He intensity ratio from the Ulysses spacecraft during its first (1992-94) and second (1999-2000) ascent to southern high latitude regions of the heliosphere. These cover a broad range of heliocentric distances (from 5.2 to 2.0 AU) and out-of-ecliptic latitudes (from 18{degree}S to 80{degree}S). During Ulysses' first southern pass, the HI-SCALE instrument measured a series of enhanced particle fluxes associated with the passage of a recurrent corotating interaction region (CIR). Low values ({approximately}6) of the H/He ratio were observed in these recurrent corotating events, with a clear minimum following the passage of the corotating reverse shock. When Ulysses reached high southern latitudes (>40{degree}S), the H/He ratio always remained below {approximately}10 except during two transient solar events that brought the ratio to high (>20) values. Ulysses' second southern pass was characterized by a higher average value of the H/He ratio. No recurrent pattern was observed in the energetic ion intensity which was dominated by the occurrence of transient events of solar origin. Numerous CIRs, many of which were bounded by forward and reverse shock pairs, were still observed in the solar wind and magnetic field data. The arrival of those CIRs at Ulysses did not always result in a decrease of the H/He ratio; on the contrary, many CIRs showed a higher H/He ratio than some transient events. Within a CIR, however, the H/He ratio usually increased around the forward shock and decreased towards the reverse shock. Throughout the second ascent to southern heliolatitudes, the H/He ratio seldom decreased below {approximately}10 even at high latitudes (>40{degree}S). We interpret these higher values of the H/He ratio in terms of the increasing level of solar activity together with the poor definition and short life that corotating solar wind structures have under solar maximum conditions. The global filling of the heliosphere by transient solar events and the fact that in 1999-2000 Ulysses observed only intermediate (<650 km s{sup {minus}1}) solar wind speed (whose contents in pick-up He is less energetic than in the fast solar wind streams observed in 1992-1994) favored the protons with respect to alpha particles. Hence the fact that the average values of the H/He ratio observed by Ulysses during the rising phase of the solar cycle (1999-2000) were higher than those observed during the declining phase (1992-1994).

J. GOSLING; D. LARIO; ET AL

2001-03-01T23:59:59.000Z

220

Device and method for electron beam heating of a high density plasma  

DOE Patents (OSTI)

A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

Thode, Lester E. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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221

Analysis of Schottky gate electron tunneling in polarization induced AlGaN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

( gate=nickel)/(barrier=GaN/Al (y) Ga (1?y) N)/(buffer=GaN)/(substrate=SiC ) polarizationinduced high electron mobility transistors (PI-HEMTs) show promise for ultrahigh power microwave amplification. The polarization fields in these Ga-face

Lester F. Eastman

1999-01-01T23:59:59.000Z

222

Advanced technologies for improving high frequency performance of AlGaN/GaN high electron mobility transistors  

E-Print Network (OSTI)

In this thesis, we have used a combination of physical analysis, numerical simulation and experimental work to identify and overcome some of the main challenges in AlGaN/GaN high electron mobility transistors (HEMTs) for ...

Chung, Jinwook W. (Jinwook Will)

2008-01-01T23:59:59.000Z

223

composites for high performance electronic packaging and thermal ...  

Science Conference Proceedings (OSTI)

The applications include; leading edges and engine components for the National Aerospace Plane, radiators for space power, flexible high conductance thermal ...

224

DIFFUSE HARD X-RAY EMISSION IN STARBURST GALAXIES AS SYNCHROTRON FROM VERY HIGH ENERGY ELECTRONS  

SciTech Connect

The origin of the diffuse hard X-ray (2-10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10-100 TeV electrons and positrons (e {sup {+-}}) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e {sup {+-}} at these energies: (1) primary electrons directly accelerated by supernova remnants, (2) pionic secondary e {sup {+-}} created by inelastic collisions between cosmic ray (CR) protons and gas nuclei in the dense interstellar medium of starbursts, and (3) pair e {sup {+-}} produced between the interactions between 10 and 100 TeV {gamma}-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic center (R {<=} 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power-law injection spectrum for electrons and protons. We consider different injection spectral slopes, magnetic field strengths, CR acceleration efficiencies, and diffusive escape times, and include advective escape, radiative cooling processes, and secondary and pair e {sup {+-}}. We compare these models to extant radio and GeV and TeV {gamma}-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and inverse Compton (IC) luminosities of these starbursts in the models which satisfy multiwavelength constraints. If the primary electron spectrum extends to {approx}PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron emission contributes 2%-20% of their unresolved, diffuse hard X-ray emission. However, there is great uncertainty in this conclusion because of the limited information on the CR electron spectrum at these high energies. IC emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic center to 10% in Arp 220's nuclei, with the main uncertainty being the starbursts' magnetic field. We also model generic starbursts, including submillimeter galaxies, in the context of the FIR-X-ray relation, finding that anywhere between 0% and 16% of the total hard X-ray emission is synchrotron for different parameters, and up to 2% in the densest starbursts assuming an E {sup -2.2} injection spectrum and a diffusive escape time of 10 Myr (E/3 GeV){sup -1/2} (h/100 pc). Neutrino observations by IceCube and TeV {gamma}-ray data from HESS, VERITAS, and CTA can further constrain the synchrotron X-ray emission of starbursts. Our models do not constrain the possibility of hard, second components of primary e {sup {+-}} from sources like pulsars in starbursts, which could enhance the synchrotron X-ray emission further.

Lacki, Brian C. [Institute for Advanced Study, Princeton, NJ 08540 (United States)] [Institute for Advanced Study, Princeton, NJ 08540 (United States); Thompson, Todd A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)] [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)

2013-01-01T23:59:59.000Z

225

A Secure Web Application Providing Public Access to High-Performance Data Intensive Scientific Resources - ScalaBLAST Web Application  

SciTech Connect

This work presents the ScalaBLAST Web Application (SWA), a web based application implemented using the PHP script language, MySQL DBMS, and Apache web server under a GNU/Linux platform. SWA is an application built as part of the Data Intensive Computer for Complex Biological Systems (DICCBS) project at the Pacific Northwest National Laboratory (PNNL). SWA delivers accelerated throughput of bioinformatics analysis via high-performance computing through a convenient, easy-to-use web interface. This approach greatly enhances emerging fields of study in biology such as ontology-based homology, and multiple whole genome comparisons which, in the absence of a tool like SWA, require a heroic effort to overcome the computational bottleneck associated with genome analysis. The current version of SWA includes a user account management system, a web based user interface, and a backend process that generates the files necessary for the Internet scientific community to submit a ScalaBLAST parallel processing job on a dedicated cluster.

Curtis, Darren S.; Peterson, Elena S.; Oehmen, Chris S.

2008-05-04T23:59:59.000Z

226

MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform  

SciTech Connect

Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

Merckel, Laura G., E-mail: L.G.Merckel-2@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Bartels, Lambertus W., E-mail: W.Bartels@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Koehler, Max O., E-mail: max.kohler@philips.com [Philips Healthcare (Finland); Bongard, H. J. G. Desiree van den, E-mail: D.vandenBongard@umcutrecht.nl [University Medical Center Utrecht, Department of Radiotherapy (Netherlands); Deckers, Roel, E-mail: R.Deckers-2@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands)] [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Mali, Willem P. Th. M., E-mail: W.Mali@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Binkert, Christoph A., E-mail: Christoph.Binkert@ksw.ch [Cantonal Hospital Winterthur, Department of Radiology (Switzerland); Moonen, Chrit T., E-mail: C.Moonen@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Gilhuijs, Kenneth G. A., E-mail: K.G.A.Gilhuijs@umcutrecht.nl; Bosch, Maurice A. A. J. van den, E-mail: mbosch@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands)

2013-04-15T23:59:59.000Z

227

Guiding of high intensity ultrashort laser pulses in plasma channels produced with the dual laser pulse ignitor-heater technique  

DOE Green Energy (OSTI)

The authors present results of experimental investigations of laser guiding in plasma channels. A new technique for plasma channel creation, the Ignitor-Heater scheme is proposed and experimentally tested in hydrogen and nitrogen. It makes use of two laser pulses. The Ignitor, an ultrashort (< 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used subsequently to heat the existing spark via inverse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. The channel density was diagnosed with time resolved longitudinal interferometry. From these measurements the plasma temperature was inferred. The guiding properties of the channels were tested by injecting a > 5 {times} 10{sup 17} W/cm{sup 2}, 75 fs laser pulse.

Volfbeyn, P.; Leemans, W.P.

1998-07-01T23:59:59.000Z

228

Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow  

Science Conference Proceedings (OSTI)

Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M. [Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Philips Healthcare Canada, Markham, ON, L6C 2S3 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Department of Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada)

2012-11-28T23:59:59.000Z

229

HIGH-VACUUM ELECTRON-BEAM FUSION WELDING  

SciTech Connect

A newly developed welding process is described for welding in a high vacuum without introducing contaminating material into the system as a part of the welding operation. (J.E.D.)

Wyman, W.L.

1958-02-01T23:59:59.000Z

230

High-voltage DC transmission: a power electronics workhorse  

Science Conference Proceedings (OSTI)

Thyristor-based HVDC converter technology is used for highly reliable power transfer across natural or national boundaries or between AC systems designed for different frequencies or incompatible frequency controls. The author discusses the benefits ...

N. G. Hingorani

1996-04-01T23:59:59.000Z

231

Electronic properties of doped Mott insulators and high temperature superconductors  

E-Print Network (OSTI)

High-temperature superconducting cuprates, which are the quintessential example of a strongly correlated system and the most extensively studied materials after semiconductors, spurred the development in the fields of ...

Ribeiro, Tiago Castro

2005-01-01T23:59:59.000Z

232

HILL: The High-Intensity Laser Laboratory Core Team's Reply to Questions from the NNSA Experimental Facilities Panel  

SciTech Connect

Question 1 - The type of physics regimes that HILL can access for weapons studies is quite interesting. The question that arises for the proposal team is what priority does this type of experimental data have versus data that can be obtained with NIF, and Z. How does HILL rank in priority compared to MARIE 1.0 in terms of the experimental data it will provide? We reiterate that isochoric heating experiments to be conducted with HILL are complementary to the high energy density physics experiments at NIF and Z and uniquely access states of matter that neither other facility can access. It is our belief that HILL will enable several important questions, e.g., as related to mix morphology, radiation transfer from corrugated surfaces, and equations of state, to be run to ground through carefully diagnosed, 'unit-physics' experiments. Such experiments will substantially improve confidence in our computer models and provide a rigorous science basis for certification. Question 2 - A secondary question relates to the interests of LLNL and SNL in the physics that HILL can address. This should be spelled out clearly. I would like to see the other labs be part of the discussion regarding how important this capability would be if built. Both sister Labs have a keen interest in the physics enabled by high-intensity, high-energy lasers, as evinced by the Z Petawatt and NIF ARC upgrades to their signature facilities. LANL scientists have teamed with scientists from both Laboratories in high-intensity laser 'first experiments' envisioned for HILL and we fully intend to continue these profitable discussions going forward. In the preparation of the HILL proposal, feedback was solicited from the broader HEDP and weapons science communities. The consensus view was that HILL filled a critical gap and that there was a need for a facility like HILL to address outstanding questions in weapons science. It was recognized that co-location of HILL with a facility such as MaRIE 1.0, Z, NIF, or Omega may offer additional advantages and we would expect these to be explored and evaluated during the CD process. Question 3 - A laser/optics experts group should review this proposal to ensure the level of R&D is reasonable to provide a sufficient chance of success (>50%). In the preparation of the HILL proposal, we sent our proposal and cost estimates to laser designers/scientists across the complex. Though risks were identified with our design, the prevailing view of those we engaged was that the risks were appropriately represented by the TRL levels assigned and that the enabling R&D planned in our proposal was adequate for risk mitigation. Question 4 - More data and peer review is needed from its sister facilities around the world. It is our specific intent to conduct both scientific and technical workshops with the user community if the High Intensity Science field is further encouraged as part of the NNSA Roadmap. Question 5 - Does HILL have to be co-located with MARIE 1.0? Is that feasible from the point of view of TA-53 real estate? Multiple siting options were considered for HILL, including co-location with MaRIE 1.0 (the most cost-effective and flexible option), as well as in a separate, stand-alone building and in a retro-fitted existing building. The cost estimate included these contingencies and candidate locations for HILL in TA-53 were identified. There is actually significant space at TA-53 on the hill in the northeast end of the mesa. Question 6 - What would be the impact on the weapons program if this facility were NOT built? An inability to elucidate aspects of weapons science in the dense plasma regime and validate computer models for same. This will lead to reduced confidence in the computer tools used for certification. Question 7 - Will HILL allow some of the x-ray vulnerability studies proposed by SPARC? If so what does Sandia's vulnerability group think of this method versus SPARC. It is possible that some of the scope envisioned for SPARC could be achieved on HILL, although likely that the energy produced at HILL not bei

Albright, B J [Los Alamos National Laboratory

2012-08-02T23:59:59.000Z

233

High density electronic circuit and process for making  

DOE Patents (OSTI)

High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits are disclosed. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing. 8 figs.

Morgan, W.P.

1999-06-29T23:59:59.000Z

234

High frequency electronic ballast for HID lamps. Technical progress report, October 1, 1993--December 31, 1994  

SciTech Connect

Electronic Ballast Systems Corp. has been working on the development of highly efficient (94%) electronic ballast for HID lamps (35W,...,400W) providing energy savings of up to thirty five percent (35%) as compared to the only available alternative, the standard core and coil HID ballasts currently on the market.

1995-03-01T23:59:59.000Z

235

Quality of Life After Hypofractionated Concomitant Intensity-Modulated Radiotherapy Boost for High-Risk Prostate Cancer  

SciTech Connect

Purpose: To evaluate the change in health-related quality of life (QOL) of patients with high-risk prostate cancer treated using hypofractionated radiotherapy combined with long-term androgen deprivation therapy. Methods and Materials: A prospective Phase I-II study enrolled patients with any of the following: clinical Stage T3 disease, prostate-specific antigen level {>=}20 ng/mL, or Gleason score 8-10. Radiotherapy consisted of 45 Gy (1.8 Gy per fraction) to the pelvic lymph nodes with a concomitant 22.5 Gy intensity-modulated radiotherapy boost to the prostate, for a total of 67.5 Gy (2.7 Gy per fraction) in 25 fractions over 5 weeks. Daily image guidance was performed using three gold seed fiducials. Quality of life was measured using the Expanded Prostate Cancer Index Composite (EPIC), a validated tool that assesses four primary domains (urinary, bowel, sexual, and hormonal). Results: From 2004 to 2007, 97 patients were treated. Median follow-up was 39 months. Compared with baseline, at 24 months there was no statistically significant change in the mean urinary domain score (p = 0.99), whereas there were decreases in the bowel (p < 0.01), sexual (p < 0.01), and hormonal (p < 0.01) domains. The proportion of patients reporting a clinically significant difference in EPIC urinary, bowel, sexual, and hormonal scores at 24 months was 27%, 31%, 55%, and 60%, respectively. However, moderate and severe distress related to these symptoms was minimal, with increases of only 3% and 5% in the urinary and bowel domains, respectively. Conclusions: Hypofractionated radiotherapy combined with long-term androgen deprivation therapy was well tolerated. Although there were modest rates of clinically significant patient-reported urinary and bowel toxicity, most of this caused only mild distress, and moderate and severe effects on QOL were limited. Additional follow-up is ongoing to characterize long-term QOL.

Quon, Harvey [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Cheung, Patrick C.F., E-mail: patrick.cheung@sunnybrook.ca [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Loblaw, D. Andrew; Morton, Gerard; Pang, Geordi; Szumacher, Ewa; Danjoux, Cyril [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Choo, Richard [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Kiss, Alex; Mamedov, Alexandre; Deabreu, Andrea [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada)

2012-06-01T23:59:59.000Z

236

RF Power Degradation of GaN High Electron Mobility Transistors  

E-Print Network (OSTI)

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

Joh, Jungwoo

237

Telecontrol of Ultra-High Voltage Electron Microscope over Global IPv6 Network  

Science Conference Proceedings (OSTI)

Osaka University has an Ultra-High VoltageElectron Microscope (UHVEM) which can provide highquality specimen images for worldwide researchers. Forusability improvements, we have worked on thetelecontrol of the UHVEM. In this paper, we would liketo introduce ...

Toyokazu Akiyama; Shinji Shimojo; Shojiro Nishio; Yoshinori Kitatsuji; Steven Peltier; Thomas Hutton; Fang-Pang Lin

2003-01-01T23:59:59.000Z

238

Electric field engineering in GaN high electron mobility transistors  

E-Print Network (OSTI)

In the last few years, AlGaN/GaN high electron mobility transistors (HEMTs) have become the top choice for power amplification at frequencies up to 20 GHz. Great interest currently exists in industry and academia to increase ...

Zhao, Xu, S.M. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

239

Multi-wavelength analysis of high energy electrons in solar flares: a case study of August 20, 2002 flare  

E-Print Network (OSTI)

A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and MDI observations with advanced methods and techniques never previously applied in the solar flare context. A new method to account for X-ray Compton backscattering in the photosphere (photospheric albedo) has been used to deduce the primary X-ray flare spectra. The mean electron flux distribution has been analysed using both forward fitting and model independent inversion methods of spectral analysis. We show that the contribution of the photospheric albedo to the photon spectrum modifies the calculated mean electron flux distribution, mainly at energies below 100 keV. The positions of the Halpha emission and hard X-ray sources with respect to the current-free extrapolation of the MDI photospheric magnetic field and the characteristics of the radio emission provide evidence of the closed geometry of the magnetic field structure and the flare process in low altitude magnetic loops. In agreement with the predictions of some solar flare models, the hard X-ray sources are located on the external edges of the Halpha emission and show chromospheric plasma heated by the non-thermal electrons. The fast changes of Halpha intensities are located not only inside the hard X-ray sources, as expected if they are the signatures of the chromospheric response to the electron bombardment, but also away from them.

J. Kasparova; M. Karlicky; E. P. Kontar; R. A. Schwartz; B. R. Dennis

2005-08-30T23:59:59.000Z

240

AGS intensity upgrades  

SciTech Connect

After the successful completion of the AGS Booster and several upgrades of the AGS, a new intensity record of 6.3 x 10{sup 13} protons per pulse accelerated to 24 GeV was achieved. The high intensity slow-extracted beam program at the AGS typically serves about five production targets and about eight experiments including three rare Kaon decay experiments. Further intensity upgrades are being discussed that could increase the average delivered beam intensity by up to a factor of four.

Roser, T.

1995-12-01T23:59:59.000Z

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


241

Generalized Courant-Snyder Theory and Kapchinskij-Vladimirskij Distribution For High-intensity Beams In A Coupled Transverse Focusing Lattice  

SciTech Connect

The Courant-Snyder (CS) theory and the Kapchinskij-Vladimirskij (KV) distribution for high-intensity beams in a uncoupled focusing lattice are generalized to the case of coupled transverse dynamics. The envelope function is generalized to an envelope matrix, and the envelope equation becomes a matrix envelope equation with matrix operations that are non-commutative. In an uncoupled lattice, the KV distribution function, first analyzed in 1959, is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high-intensity beams including self-fields in a self-consistent manner. The KV solution is generalized to high-intensity beams in a coupled transverse lattice using the generalized CS invariant. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space. The fully self-consistent solution reduces the nonlinear Vlasov-Maxwell equations to a nonlinear matrix ordinary differential equation for the envelope matrix, which determines the geometry of the pulsating and rotating beam ellipse. These results provide us with a new theoretical tool to investigate the dynamics of high-intensity beams in a coupled transverse lattice. A strongly coupled lattice, a so-called N-rolling lattice, is studied as an example. It is found that strong coupling does not deteriorate the beam quality. Instead, the coupling induces beam rotation, and reduces beam pulsation.

Hong QIn, Ronald Davidson

2011-07-18T23:59:59.000Z

242

The Impact of Intrinsic Heavy Quark Distributions in the Proton on New Physics Searches at the High Intensity Frontier  

SciTech Connect

The possibility of an intense proton facility, at 'Project X' or elsewhere, will provide many new opportunities for searches for physics beyond the Standard Model. A Project X can serve a yet broader role in the search for new physics, and in this note we highlight the manner in which thus-enabled studies of the flavor structure of the proton, particularly of its intrinsic heavy quark content, facilitate other direct and indirect searches for new physics. Intrinsic heavy quarks in both light and heavy hadrons play a key role in searches for physics BSM with hadrons - and their study at the Intensity Frontier may prove crucial to establishing its existence.

Brodsky, Stanley; /SLAC; Gardner, Susan; /Kentucky U.

2012-02-16T23:59:59.000Z

243

High Efficiency Driving Electronics for General Illumination LED Luminaires  

SciTech Connect

New generation of standalone LED driver platforms developed, which are more efficient These LED Drivers are more efficient (?90%), smaller in size ( 0.15 in3/watt), lower in cost ( 12 cents/watt in high volumes in millions of units). And these products are very reliable having an operating life of over 50,000 hours. This technology will enable growth of LED light sources in the use. This will also help in energy saving and reducing total life cycle cost of LED units. Two topologies selected for next generation of LED drivers: 1) Value engineered single stage Flyback topology. This is suitable for low powered LED drivers up to 50W power. 2) Two stage boost power factor correction (PFC) plus LLC half bridge platform for higher powers. This topology is suitable for 40W to 300W LED drivers. Three new product platforms were developed to cover a wide range of LED drivers: 1) 120V 40W LED driver, 2) Intellivolt 75W LED driver, & 3) Intellivolt 150W LED driver. These are standalone LED drivers for rugged outdoor lighting applications. Based on these platforms number of products are developed and successfully introduced in the market place meeting key performance, size and cost goals.

Upadhyay, Anand

2012-10-31T23:59:59.000Z

244

FLUKA calculations of radionuclides, star, and neutron fluence in soil around high-energy electron and proton linear accelerators  

E-Print Network (OSTI)

FLUKA calculations of radionuclides, star, and neutron fluence in soil around high-energy electron and proton linear accelerators

Puryear, A; Rokni, S H

2002-01-01T23:59:59.000Z

245

Research on Active Power Factor Correction of the Electronic Ballast for High-Pressure Sodium Lamps Based on L6563  

Science Conference Proceedings (OSTI)

In the recent years, there has been a growing interest in the design of high-pressure sodium lamp electronic ballast. Two measures are proposed to improve the power factor of high-pressure sodium lamp electronic ballasts from the definition of harmonic ... Keywords: high-pressure sodium lamps, electronic ballast, active power factor correction, L6563

Sun Jing

2010-06-01T23:59:59.000Z

246

Very heavily electron-doped CrSi2 as a high performance high temperature thermoelectric material  

SciTech Connect

We analyze the thermoelectric behavior, using first principles and Boltzmann transport calculations, of very heavily electron-doped CrSi2 and find that at temperatures of 1250 K and electron dopings of $1-4 \\times10^{21}$ cm$^{-3}$, thermopowers as large or larger in magnitude than 200 $\\mathrm{\\mu}$V/K may be found. Such high thermopowers at such high carrier concentrations are extremely rare, and suggest that good thermolectric performance (i.e. ZT) may be found in these ranges of temperature and doping.

Parker, David S [ORNL; Singh, David J [ORNL

2012-01-01T23:59:59.000Z

247

Transmission electron microscopy characterization of electrically stressed AlGaN/GaN high electron mobility transistor devices  

Science Conference Proceedings (OSTI)

A set of AlGaN/GaN high electron mobility transistor devices has been investigated using step-stress testing, and representative samples of undegraded, source-side-degraded, and drain-side-degraded devices were examined using electron microscopy and microanalysis. An unstressed reference sample was also examined. All tested devices and their corresponding transmission electron microscopy samples originated from the same wafer and thus received nominally identical processing. Step-stressing was performed on each device and the corresponding current voltage characteristics were generated. Degradation in electrical performance, specifically greatly increased gate leakage current, was shown to be correlated with the presence of crystal defects near the gate edges. However, the drain-side-degraded device showed a surface pit on the source side, and another region of the same device showed no evidence of damage. Moreover, significant metal diffusion into the barrier layer from the gate contacts was also observed, as well as thin amorphous oxide layers below the gate metal contacts, even in the unstressed sample. Overall, these observations emphasize that gate-edge defects provide only a partial explanation for device failure.

Johnson, Michael [Arizona State University; Cullen, David A [ORNL; Liu, Lu [University of Florida; Kang, Tsung Sheng [University of Florida, Gainesville; Ren, F. [University of Florida; Chang, C. Y. [University of Florida; Pearton, S. J. [University of Florida; Jang, Soohwan [University of Florida, Gainesville; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Smith, David J [Arizona State University

2012-01-01T23:59:59.000Z

248

Exploring electronic structure through high-resolution hard x-ray  

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

Exploring electronic structure through high-resolution hard x-ray Exploring electronic structure through high-resolution hard x-ray spectroscopies Tuesday, July 23, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Dimosthenis Sokaras, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory Modern high brilliance beamlines coupled with recent advances in hard-x-ray optics are establishing high-resolution hard x-ray spectroscopies as a powerful analytical tool for routine electronic structure investigations. Their advantageous characteristics like the chemical sensitivity or the hard x-rays penetration depth, that permits the implementation of difficult sample environments, expand the applicability of the relevant studies to multidisciplinary scientific fields. Simultaneously, the experimental

249

Experimental demonstration of high quality MeV ultrafast electron diffraction  

SciTech Connect

The simulation optimization and an experimental demonstration of improved performances of mega-electron-volt ultrafast electron diffraction (MeV UED) are reported in this paper. Using ultrashort high quality electron pulses from an S-band photocathode rf gun and a polycrystalline aluminum foil as the sample, we experimentally demonstrated an improved spatial resolution of MeV UED, in which the Debye-Scherrer rings of the (111) and (200) planes were clearly resolved. This result showed that MeV UED is capable to achieve an atomic level spatial resolution and a -100 fs temporal resolution simultaneously, and will be a unique tool for ultrafast structural dynamics studies.

Li, R.; Tang, C., Du, Y., Huang, W., Du, Q., Shi, J., Yan, L., Wang, X.

2009-08-18T23:59:59.000Z

250

Printing Highly-aligned Single-crystalline Organic Electronic Thin Films |  

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

Printing Highly-aligned Single-crystalline Organic Electronic Thin Films Printing Highly-aligned Single-crystalline Organic Electronic Thin Films Monday, September 23, 2013 Organic semiconductor materials have some intriguing advantages compared to their inorganic counterparts: low-cost and versatile manufacturing (e.g. roll-to-roll printing), material abundance and new form factors (e.g. flexible, transparent and stretchable). However, solution-processed organic devices are usually made and optimized with poorly scalable fabrication using lab-based techniques such as spin coating or dip coating. A better route for organic-electronics fabrication is printing, which can potentially realize large-area, high-throughput, low-cost fabrication on an industrial scale. Fluence image FLUENCE: fluid-enhanced crystal engineering. Solution shearing (a) using a

251

Electron Injection at High Mach Number Quasi-Perpendicular Shocks : Surfing and Drift Acceleration  

E-Print Network (OSTI)

Electron injection process at high Mach number collisionless quasi-perpendicular shock waves is investigated by means of one-dimensional electromagnetic particle-in-cell simulations. We find that energetic electrons are generated through the following two steps: (1) electrons are accelerated nearly perpendicular to the local magnetic field by shock surfing acceleration at the leading edge of the shock transition region. (2) the preaccelerated electrons are further accelerated by shock drift acceleration. As a result, energetic electrons are preferentially reflected back to the upstream. Shock surfing acceleration provides sufficient energy required for the reflection. Therefore, it is important not only for the energization process by itself, but also for triggering the secondary acceleration process. We also present a theoretical model of the two-step acceleration mechanism based on the simulation results, which can predict the injection efficiency for subsequent diffusive shock acceleration process. We show that the injection efficiency obtained by the present model agrees well with the value obtained by Chandra X-ray observations of SN 1006. At typical supernova remnant shocks, energetic electrons injected by the present mechanism can self-generate upstream Alfven waves, which scatter the energetic electrons themselves.

T. Amano; M. Hoshino

2006-12-08T23:59:59.000Z

252

Evolution of structural defects associated with electrical degradation in AlGaN/GaN high electron mobility transistors  

E-Print Network (OSTI)

We have investigated the surface morphology of electrically stressed AlGaN/GaN high electron mobility transistors using atomic force microscopy and scanning electron microscopy after removing the gate metallization by ...

Makaram, Prashanth

253

High-Resolution Infrared and Electron-Diffraction Studies of Trimethylenecyclopropane ([3]-Radialene)  

SciTech Connect

Combined high-resolution spectroscopic, electron-diffraction, and quantum theoretical methods are particularly advantageous for small molecules of high symmetry and can yield accurate structures that reveal subtle effects of electron delocalization on molecular bonds. The smallest of the radialene compounds, trimethylenecyclopropane, [3]-radialene, has been synthesized and examined in the gas phase by these methods. The first high-resolution infrared spectra have been obtained for this molecule of D3h symmetry, leading to an accurate B0 rotational constant value of 0.1378629(8) cm-1, within 0.5% of the value obtained from electronic structure calculations (density functional theory (DFT) B3LYP/cc-pVTZ). This result is employed in an analysis of electron-diffraction data to obtain the rz bond lengths (in Ĺ): C-H = 1.072 (17), C-C = 1.437 (4), and C=C = 1.330 (4). The analysis does not lead to an accurate value of the HCH angle; however, from comparisons of theoretical and experimental angles for similar compounds, the theoretical prediction of 117.5? is believed to be reliable to within 2?. The effect of electron delocalization in radialene is to reduce the single C-C bond length by 0.07 Ĺ compared to that in cyclopropane.

Wright, Corey R.; Holmes, Joshua; Nibler, Joseph W.; Hedberg, Kenneth; White, James D.; Hedberg, Lise; Weber, Alfons; Blake, Thomas A.

2013-05-16T23:59:59.000Z

254

Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams  

Science Conference Proceedings (OSTI)

The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.

Ratner, Daniel; /Stanford U. /SLAC

2012-05-25T23:59:59.000Z

255

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

Science Conference Proceedings (OSTI)

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

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

2002-08-01T23:59:59.000Z

256

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

Science Conference Proceedings (OSTI)

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

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

2004-06-21T23:59:59.000Z

257

Energy distribution of nonequilibrium electrons and optical phonons in GaAs under band-to-band pumping by intense short pulses of light  

SciTech Connect

Deviation from the Fermi distribution of nonequilibrium electrons and distribution of 'hot' optical phonons in GaAs under band-to-band pumping by picosecond pulses of light are calculated.

Altybaev, G. S.; Kumekov, S. E., E-mail: skumekov@mail.ru; Mahmudov, A. A. [Satpaev Kazakh National Technical University (Kazakhstan)

2009-03-15T23:59:59.000Z

258

Schottky-Drain Technology for AlGaN/GaN High-Electron Mobility Transistors  

E-Print Network (OSTI)

In this letter, we demonstrate 27% improvement in the buffer breakdown voltage of AlGaN/GaN high-electron mobility transistors (HEMTs) grown on Si substrate by using a new Schottky-drain contact technology. Schottky-drain ...

Lu, Bin

259

Time response of the high-field electron distribution function in GaAs  

Science Conference Proceedings (OSTI)

Numerical calculations have been made of the high-field electron distribution function for GaAs, its small-signal frequency response and its behavior in large sinusoidal electric fields-The response speed is limited by the low scattering rate within ...

H. D. Rees

1969-09-01T23:59:59.000Z

260

Effect of trapping on the critical voltage for degradation in gan high electron mobility transistors  

E-Print Network (OSTI)

We have performed V[subscript DS] = 0 V and OFF-state step-stress experiments on GaN-on-Si and GaN-on-SiC high electron mobility transistors under UV illumination and in the dark. We have found that for both stress conditions, ...

Demirtas, Sefa

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261

Towards a curriculum for electronic textiles in the high school classroom  

Science Conference Proceedings (OSTI)

This paper proposes a curriculum for a high school e-textile course-a curriculum rooted in our experiences in developing an e-textile construction kit and in holding several courses and workshops with these materials. The paper briefly describes the ... Keywords: computational crafts, e-textiles, electronic textiles, wearable computing

Leah Buechley; Mike Eisenberg; Nwanua Elumeze

2007-06-01T23:59:59.000Z

262

Stability of very-high pressure arc discharges against perturbations of the electron temperature  

Science Conference Proceedings (OSTI)

We study the stability of the energy balance of the electron gas in very high-pressure plasmas against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion equation, we apply the model to a very high-pressure (100 bar) xenon plasma and find instability for electron temperatures, T{sub e}, in a window between 2400 K and 5500-7000 K x 10{sup 3} K, depending on the current density (10{sup 6}-10{sup 8} A/m{sup 2}). The instability can be traced back to the Joule heating of the electron gas being a growing function of T{sub e}, which is due to a rising dependence of the electron-atom collision frequency on T{sub e}. We then analyze the T{sub e} range occurring in very high-pressure xenon lamps and conclude that only the near-anode region exhibits T{sub e} sufficiently low for this instability to occur. Indeed, previous experiments have revealed that such lamps develop, under certain conditions, voltage oscillations accompanied by electromagnetic interference, and this instability has been pinned down to the plasma-anode interaction. A relation between the mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is discussed.

Benilov, M. S. [Departamento de Fisica, Ciencias Exactas e Engenharia, Universidade da Madeira, Largo do Municipio, Funchal 9000 (Portugal); Hechtfischer, U. [Philips Lighting, BU Automotive Lamps, Technology, Philipsstrasse 8, Aachen 52068 (Germany)

2012-04-01T23:59:59.000Z

263

Nuclear quadrupole resonance of an electronically excited state from high-resolution hole-burning spectroscopy  

E-Print Network (OSTI)

Nuclear quadrupole resonance of an electronically excited state from high-resolution hole-burning 2003; published 5 May 2003 Hole-burning spectroscopy can eliminate inhomogeneous broadening and thereby, the homogeneous linewidth is often small compared to the splittings due to nuclear-spin interactions. Hole-burning

Suter, Dieter

264

Electronic  

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

contribution contribution to friction on GaAs: An atomic force microscope study Yabing Qi, 1,2 J. Y. Park, 2 B. L. M. Hendriksen, 2 D. F. Ogletree, 2 and M. Salmeron 2,3 1 Applied Science and Technology Graduate Group, University of California, Berkeley, California 94720, USA 2 Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA 3 Department of Materials Sciences and Engineering, University of California, Berkeley, California 94720, USA ͑Received 23 January 2008; revised manuscript received 11 April 2008; published 7 May 2008͒ The electronic contribution to friction at semiconductor surfaces was investigated by using a Pt-coated tip with 50 nm radius in an atomic force microscope sliding against an n-type GaAs͑100͒ substrate. The GaAs surface was covered by an approximately 1 nm thick oxide layer. Charge accumulation

265

Formation of silver nanoparticles inside a soda-lime glass matrix in the presence of a high intensity Ar{sup +} laser beam  

SciTech Connect

Formation and motion of the silver nanoparticles inside an ion-exchanged soda-lime glass in the presence of a focused high intensity continuous wave Ar{sup +} laser beam (intensity: 9.2 x 10{sup 4} W/cm{sup 2}) have been studied in here. One-dimensional diffusion equation has been used to model the diffusion of the silver ions into the glass matrix, and a two-dimensional reverse diffusion model has been introduced to explain the motion of the silver clusters and their migration toward the glass surface in the presence of the laser beam. The results of the mentioned models were in agreement with our measurements on thickness of the ion-exchange layer by means of optical microscopy and recorded morphology of the glass surface around the laser beam axis by using a Mirau interferometer. SEM micrographs were used to extract the size distribution of the migrated silver particles over the glass surface.

Niry, M. D.; Khalesifard, H. R. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Optics Research Center, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Mostafavi-Amjad, J.; Ahangary, A. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Azizian-Kalandaragh, Y. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Department of Physics, University of Mohaghegh Ardabili (UMA), P.O. Box 179, Ardabil (Iran, Islamic Republic of)

2012-02-01T23:59:59.000Z

266

High-Precision Cross Sections for Low-Energy Electron-Atom Collisions  

Science Conference Proceedings (OSTI)

We describe a recently developed B-spline R-matrix method for electron and photon collisions with atoms and ions. Using non-orthogonal sets of orbitals to construct the target description and to represent the scattering functions, this implementation of the close-coupling approach allows us to employ highly correlated target wavefunctions with relatively small configuration expansions. Example results from recent applications of the method for accurate calculations of low-energy electron scattering from He, Zn, Ne, Ar, Xe, and Fe+ are presented.

Bartschat, Klaus; Zatsarinny, Oleg [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States)

2007-04-06T23:59:59.000Z

267

High electron mobility in Ga(In)NAs films grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

We report the highest mobility values above 2000 cm{sup 2}/Vs in Si doped GaNAs film grown by molecular beam epitaxy. To understand the feature of the origin which limits the electron mobility in GaNAs, temperature dependences of mobility were measured for high mobility GaNAs and referential low mobility GaInNAs. Temperature dependent mobility for high mobility GaNAs is similar to the GaAs case, while that for low mobility GaInNAs shows large decrease in lower temperature region. The electron mobility of high quality GaNAs can be explained by intrinsic limiting factor of random alloy scattering and extrinsic factor of ionized impurity scattering.

Miyashita, Naoya; Ahsan, Nazmul; Monirul Islam, Muhammad; Okada, Yoshitaka [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Inagaki, Makoto [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511, Aichi (Japan); Yamaguchi, Masafumi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511, Aichi (Japan)

2012-11-26T23:59:59.000Z

268

Simulation of dynamics of radiation belt electrons during geomagnetic storms driven by high speed solar wind streams.  

E-Print Network (OSTI)

??Satellite observations have shown that fluxes of relativistic electrons in the earth's radiation belts can vary by orders of magnitude during periods of high solar… (more)

Yu, Bin

2007-01-01T23:59:59.000Z

269

Coupled force-balance and particle-occupation rate equations for high-field electron transport  

SciTech Connect

It is pointed out that in the framework of balance-equation approach, the coupled force-balance and particle-occupation rate equations can be used as a complete set of equations to determine the high-field transport of semiconductors in both strong and weak electron-electron interaction limits. We call to attention that the occupation rate equation conserves the total particle number and maintains the energy balance of the relative electron system, and there is no need to introduce any other term in it. The addition of an energy-drift term in the particle-occupation rate equation [Phys. Rev. B 71, 195205 (2005)] is physically inadequate for the violation of the total particle-number conservation and the energy balance. It may lead to a substantial unphysical increase of the total particle number by the application of a dc electric field.

Lei, X. L. [Department of Physics, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030 (China)

2008-01-15T23:59:59.000Z

270

High Energy Electron Signals from Dark Matter Annihilation in the Sun  

Science Conference Proceedings (OSTI)

In this paper we discuss two mechanisms by which high energy electrons resulting from dark matter annihilations in or near the Sun can arrive at the Earth. Specifically, electrons can escape the sun if DM annihilates into long-lived states, or if dark matter scatters inelastically, which would leave a halo of dark matter outside of the sun. Such a localized source of electrons may affect the spectra observed by experiments with narrower fields of view oriented towards the sun, such as ATIC, differently from those with larger fields of view such as Fermi. We suggest a simple test of these possibilities with existing Fermi data that is more sensitive than limits from final state radiation. If observed, such a signal will constitute an unequivocal signature of dark matter.

Schuster, Philip; /SLAC; Toro, Natalia; /Stanford U., ITP; Weiner, Neal; Yavin, Itay; /New York U., CCPP

2012-04-09T23:59:59.000Z

271

Scattering and electron mobility in combination-doped HFET-structures AlGaAs/InGaAs/AlGaAs with high electron density  

Science Conference Proceedings (OSTI)

Molecular-beam epitaxy is used for growing structures differing in doping technique and doping level and having a high two-dimensional-electron concentration n{sub s} in the quantum well. The effect of doping combining uniform and {delta} doping on the electron-transport properties of heterostructures is investigated. A new type of structure with a two-sided silicon {delta} doping of GaAs transition layers located on the quantum-well boundaries is proposed. The largest value of electron mobility {mu}{sub H} = 1520 cm{sup 2}/(V s) is obtained simultaneously with a high electron density n{sub s} = 1.37 Multiplication-Sign 10{sup 13} cm{sup -2} at 300 K with such a doping. It is associated with decreasing electron scattering by an ionized impurity, which is confirmed by the carried out calculations.

Khabibullin, R. A., E-mail: khabibullin_r@mail.ru; Vasil'evskii, I. S. [MEPHI National Research Nuclear University (Russian Federation); Galiev, G. B.; Klimov, E. A. [Russian Academy of Sciences, Institute of Ultrahigh-Frequency Semiconductor Electronics (Russian Federation); Ponomarev, D. S. [MEPHI National Research Nuclear University (Russian Federation); Lunin, R. A.; Kulbachinskii, V. A. [Moscow State University (Russian Federation)

2011-10-15T23:59:59.000Z

272

Neutron-induced electronic failures around a high-energy linear accelerator  

Science Conference Proceedings (OSTI)

Purpose: After a new in-vault CT-on-rails system repeatedly malfunctioned following use of a high-energy radiotherapy beam, we investigated the presence and impact of neutron radiation on this electronic system, as well as neutron shielding options. Methods: We first determined the CT scanner's failure rate as a function of the number of 18 MV monitor units (MUs) delivered. We then re-examined the failure rate with both 2.7-cm-thick and 7.6-cm-thick borated polyethylene (BPE) covering the linac head for neutron shielding. To further examine shielding options, as well as to explore which neutrons were relevant to the scanner failure, Monte Carlo simulations were used to calculate the neutron fluence and spectrum in the bore of the CT scanner. Simulations included BPE covering the CT scanner itself as well as covering the linac head. Results: We found that the CT scanner had a 57% chance of failure after the delivery of 200 MUs. While the addition of neutron shielding to the accelerator head reduced this risk of failure, the benefit was minimal and even 7.6 cm of BPE was still associated with a 29% chance of failure after the delivery of 200 MU. This shielding benefit was achieved regardless of whether the linac head or CT scanner was shielded. Additionally, it was determined that fast neutrons were primarily responsible for the electronic failures. Conclusions: As illustrated by the CT-on-rails system in the current study, physicists should be aware that electronic systems may be highly sensitive to neutron radiation. Medical physicists should therefore monitor electronic systems that have not been evaluated for potential neutron sensitivity. This is particularly relevant as electronics are increasingly common in the therapy vault and newer electronic systems may exhibit increased sensitivity.

Kry, Stephen F.; Johnson, Jennifer L.; White, R. Allen; Howell, Rebecca M.; Kudchadker, Rajat J.; Gillin, Michael T. [Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Department of Biostatistics and Applied Mathematics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States) and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States) and Health Science Center Houston, Graduate School of Biomedical Sciences, University of Texas, Houston, Texas 77030 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

2011-01-15T23:59:59.000Z

273

The effect of high-energy electron-beam irradiation on microstructural modification of a high-speed steel roll  

SciTech Connect

The purpose of this study is to investigate the microstructural modification in a high-speed steel (HSS) roll irradiated with an accelerated high-energy electron beam. The HSS roll samples were irradiated at the beam travel speeds of 2.5 to 25 mm/s using an electron accelerator (1.4 MeV). The microstructure was examined with a scanning electron microscope (SEM) capable of in situ fracture testing and simultaneous measurement of the apparent fracture toughness. Irradiation changed the matrix phase from tempered martensite to a mixture of retained austenite and martensite. Coarse primary carbides were partially or completely dissolved, depending on the heat input. Irradiation greatly improved the fracture properties because of the presence of retained austenite, which could retard crack propagation, although hardness was decreased. Occasional interior quench cracks were found in the heat-affected region. Appropriate processing methods, such as pre- or postirradiation, were suggested. A heat transfer analysis of the irradiated surface layer was also carried out to elucidate the influence of the irradiation parameters on the microstructure.

Suh, D.; Lee, S.; Koo, Y. [Pohang Univ. of Science and Technology (Korea, Republic of); Lee, H.C. [Kangwon Industries, Ltd., Pohang (Korea, Republic of). Roll Technology Dept.

1996-10-01T23:59:59.000Z

274

High mobility two-dimensional electron gases in nitride heterostructures with high Al composition AlGaN alloy barriers  

Science Conference Proceedings (OSTI)

We report high-electron mobility nitride heterostructures with >70% Al composition AlGaN alloy barriers grown by molecular beam epitaxy. Direct growth of such AlGaN layers on GaN resulted in hexagonal trenches and a low mobility polarization-induced charge. By applying growth interruption at the heterojunction, the surface morphology improved dramatically and the room temperature two-dimensional electron gas (2DEG) mobility increased by an order of magnitude, exceeding 1300 cm{sup 2}/V s. The 2DEG density was tunable at 0.4-3.7x10{sup 13}/cm{sup 2} by varying the total barrier thickness (t). Surface barrier heights of the heterostructures were extracted and exhibited dependence on t.

Li Guowang; Cao Yu; Xing Huili Grace; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2010-11-29T23:59:59.000Z

275

HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION  

SciTech Connect

During Phase I, the following goals were achieved: (1) design and fabrication of a novel, nano-dimensional CNT field emitter assembly for high current density application, with high durability; (2) fabrication of a ceramic based micro channel plate (MCP) and characterization of its secondary electron emission; and (3) characterizing the CNT/MCP cathode for high field emission and durability. As a result of these achievements, a relatively high current density of ~ 1.2 A/cm2 from a CNT cathode and single channel MCP were measured. The emission current was also extremely stable with a peak-to-peak variation of only 1.8%. The emission current could be further enhanced to meet requirements for electron lens applications by increasing the number of MCP channels. A calculation for maximum possible current density with a 1200 channel/cm2 MCP, placed over a cathode with 1200 uniformly functioning CNTs, would be ~1.46 kA/cm2, neglecting space charge limitations. Clearly this level of emission is far greater than what is needed for the electron lens application, but it does offer a highly comforting margin to account for sub-standard emitters and/or to allow the lesser challenge of building a cathode with fewer channels/cm2. A satisfactory goal for the electron lens application would be a controllable emission of 2-4 mA per channel in an ensemble of 800-1200 uniformly-functioning channels/cm2, and a cathode with overall area of about 1 cm2.

Hirshfield, Jay L

2012-12-28T23:59:59.000Z

276

Performance of GAASP/GAAS Superlattice Photocathodes in High Energy Experiments using Polarized Electrons  

Science Conference Proceedings (OSTI)

The GaAsP/GaAs strained superlattice photocathode structure has proven to be a significant advance for polarized electron sources operating with high peak currents per microbunch and relatively low duty factor. This is the characteristic type of operation for SLAC and is also planned for the ILC. This superlattice structure was studied at SLAC [1], and an optimum variation was chosen for the final stage of E-158, a high-energy parity violating experiment at SLAC. Following E-158, the polarized source was maintained on standby with the cathode being re-cesiated about once a week while a thermionic gun, which is installed in parallel with the polarized gun, supplied the linac electron beams. However, in the summer of 2005, while the thermionic gun was disabled, the polarized electron source was again used to provide electron beams for the linac. The performance of the photocathode 24 months after its only activation is described and factors making this possible are discussed.

Brachmann, A.; Clendenin, J.E.; Maruyama, T.; Garwin, E.L.; Ioakemidi, K.; Prescott, C.Y.; Turner, J.L.; /SLAC; Prepost, R.; /Wisconsin U., Madison

2006-02-27T23:59:59.000Z

277

The uses of electron beam ion traps in the study of highly charged ions  

SciTech Connect

The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

Knapp, D.

1994-11-02T23:59:59.000Z

278

Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions  

SciTech Connect

We present results from the grant entitled, ���¢��������Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions.���¢������� The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

Mori, Warren, B.

2012-12-01T23:59:59.000Z

279

High-resolution data of the Iceland Basin geomagnetic excursion from ODP sites 1063 and 983: Existence of intense flux  

E-Print Network (OSTI)

High-resolution data of the Iceland Basin geomagnetic excursion from ODP sites 1063 and 983-resolution records of the 185 kyr Iceland Basin (IB) geomagnetic excursion from Ocean Drilling Project (ODP) Site reserved. Keywords: Geomagnetic excursions; Iceland Basin excursion; Preferred VGP longitudes; Patches

Niocaill, Conall Mac

280

Field Guide: Compressors for High-Voltage Circuit Breakers, Optimized for Electronic Viewing  

Science Conference Proceedings (OSTI)

High-voltage circuit breakers perform essential protection and control functions on power transmission networks. A circuit breaker that fails to operate within its design time period may cause serious damage and extended outages. Proper maintenance of compressors can help to ensure that breakers operate reliably and can prevent premature failures. This field guide, which has been optimized for use on electronic devices such as smart phones and tablets, is intended to help utility field personnel properly...

2011-11-09T23:59:59.000Z

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


281

Universality of electron distributions in high-energy air showers - description of Cherenkov light production  

E-Print Network (OSTI)

The shower simulation code CORSIKA has been used to investigate the electron energy and angular distributions in high-energy showers. Based on the universality of both distributions, we develop an analytical description of Cherenkov light emission in extensive air showers, which provides the total number and angular distribution of photons. The parameterisation can be used e.g. to calculate the contribution of direct and scattered Cherenkov light to shower profiles measured with the air fluorescence technique.

F. Nerling; J. Blümer; R. Engel; M. Risse

2005-06-29T23:59:59.000Z

282

High harmonic attosecond pulse train amplification in a free electron laser  

SciTech Connect

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

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

2011-03-04T23:59:59.000Z

283

(Interaction of slow electrons with high-pressure gases (quasi-liquids): synthesis of our knowledge on slow electron-molecule interactions. Progress report for year ending May 31, 1981  

SciTech Connect

Research on electron interactions with molecules at high pressure is reported. This includes electron collisions with chlorofluoroethanes; temperature dependence of electron attachment to halocarbons; electron energy distribution functions in argon; the role of electron attachment in the breakdown strength of gaseous dielectrics; a new high temperature swarm experiment; electron scattering from molecules of environmental interest; negative ions of polyatomic molecules; electron motion in high pressure polar gases (NH/sub 3/); fast gases for radiation detectors; and electron affinities of atoms and molecules. (GHT)

Christophorou, L.G.; McCorkle, D.L.

1981-01-01T23:59:59.000Z

284

Design and testing of an electron cyclotron resonance heating ion source for use in high field compact superconducting cyclotrons  

E-Print Network (OSTI)

The main goal of this project is to evaluate the feasibility of axial injection of a high brightness beam from an Electron Cyclotron Resonance ion source into a high magnetic field cyclotron. Axial injection from an ion ...

Artz, Mark E

2012-01-01T23:59:59.000Z

285

Spectral broadening and compression of high-intensity laser pulses in quasi-periodic systems with Kerr nonlinearity  

SciTech Connect

We report the results of theoretical studies and numerical simulations of optical high-power pulse compression systems based on the spectral broadening in a Kerr nonlinear medium with subsequent pulse compression in a dispersive delay line. It is shown that the effective spectral broadening requires suppressing a smallscale instability arising due to self-focusing, which is possible in quasi-periodic systems consisting of a nonlinear medium and optical relay telescopes transmitting images of the laser beam through the system. The numerical calculations have shown the possibility of broadening the spectrum, followed by 15-fold pulse compression until the instability is excited. (control of laser radiation parameters)

Vlasov, Sergei N; Koposova, E V; Yashin, V E

2012-11-30T23:59:59.000Z

286

Ultra high-gradient energy loss by a pulsed electron beam in a plasma  

SciTech Connect

The plasma wake-field mechanism can be used to couple energy at a high rate from a bunched electron beam into a plasma wave. We will present results from the Fermilab A0 facility where a beam with an initial energy of 14 MeV passes through the plasma to emerge with a much broader energy spread, spanning from a low of 3 MeV to a high of over 20 MeV. Over the 8 cm length of the 10{sup 14} cm{sup -3} plasma, this implies a 140 MeV/m deceleration and 72 MeV/m acceleration gradient.

Nikolai Barov et al.

2001-12-19T23:59:59.000Z

287

The effects of intense magnetic fields on Landau levels in a neutron star  

E-Print Network (OSTI)

In this paper, an approximate method of calculating the Fermi energy of electrons ($E_{F}(e)$) in a high-intensity magnetic field, based on the analysis of the distribution of a neutron star magnetic field, has been proposed. In the interior of a Neutron star, different forms of intense magnetic field could exist simultaneously and a high electron Fermi energy could be generated by the release of magnetic field energy. The calculation results show that: $E_{F}(e)$ is related to density $\\rho$, the mean electron number per baryon $Y_{e}$ and magnetic field strength $B$.

Gao, Z F; Song, D L; Yuan, J P; Chou, C K

2013-01-01T23:59:59.000Z

288

RHIC PRESSURE RISE AND ELECTRON CLOUD.  

SciTech Connect

In RHIC high intensity operation, two types of pressure rise are currently of concern. The first type is at the beam injection, which seems to be caused by the electron multipacting, and the second is the one at the beam transition, where the electron cloud is not the dominant cause. The first type of pressure rise is limiting the beam intensity and the second type might affect the experiments background for very high total beam intensity. In this article, the pressure rises at RHIC are described, and preliminary study results are reported. Some of the unsettled issues and questions are raised, and possible counter measures are discussed.

Zhang, S Y; Blaskiewicz, M; Cameron, P; Drees, P; Afischer, W; Gassner, D; Gullotta, J; He, P; Hseuh, H; Chuang, H; Iriso-Aziz, U; Lee, R; Mackay, W; Woerter, B; Ptitsyn, V; Ponnaiyan, V; Roser, T; Satogata, T; Smart, L; Trbojevic, D

2003-05-12T23:59:59.000Z

289

A PROPOSAL FOR THE Mc$sup 2$ ISOCHRONOUS CYCLOTRON. A GENERAL PURPOSE HIGH- INTENSITY 810-Mev PROTON ACCELERATOR  

SciTech Connect

An isochronous eight-sector proton cyclotron to provide an extracted beam in excess of 100 mu amp at 810 Mev is proposed. The primary proton beam and the secondary meson and neutron beams will be used to investigate nuclear structure and the interactions between elementary particles. Biomedical and space-oriented research programs are also planned. Shielded research areas and an extensive beam transport and analysis system are provided. Theoretical and experimental studies have shown that the Mc/sup 2/ Cyclotron in a practival concept; high extraction efficiencies can be obtained, and the residual radiation problems are manageable. The project would require less than seven years to complete and would cost about ,000,000. (auth)

1963-11-01T23:59:59.000Z

290

Electron Quasielastic Scattering at High Energy from $^{56}$Fe, What Suppression?  

E-Print Network (OSTI)

Quasielastic electron scattering $(e,e')$ from $^{56}$Fe is calculated at large electron energies (2-4 GeV) and large three momentum transfer (0.5-1.5 GeV/c). We use a relativistic mean-field single particle model for the bound and continuum nucleon wavefunctions based on the $\\sigma-\\omega$ model and we include the effects of electron Coulomb distortion in the calculation. The calculations are compared to high energy data from SLAC and more recent data from Jefferson Laboratory, particularly for kinematics where the energy transfer is less than 500 to 600 MeV and the quasielastic process is expected to dominate the cross section. The effects of the predicted weakening of the strong scalar and vector potentials of the $\\sigma-\\omega$ model at high energy are investigated. Possible evidence for `longitudinal suppression' or modifications of nucleon form factors in the medium is considered, but neither is necessary to explain the quasielastic data for four momentum transfers less than 1 (GeV/c)$^2$.

K. S. Kim; L. E. Wright

2002-08-21T23:59:59.000Z

291

High-dielectric-constant ferroelectric thin film and bulk ceramic capacitors for power electronics.  

DOE Green Energy (OSTI)

Significant effort is presently focused on reducing the size and weight of power electronic modules. To achieve these goals in high-power capacitors, alternative materials and fabrication processes are needed. Thin film (<0.5 {micro}m) and bulk capacitors that use perovskite-based ferroelectric dielectrics are promising alternative technologies. Ferroelectrics possess high dielectric constants, thus offering substantial increases in volumetric capacitance. In thin film form, these materials display low loss and high breakdown strength. The unique properties of some of these materials, such as a nonlinear dielectric response or a high energy-storage capacity accompanying a phase change, can be exploited for power electronic capacitors. Prototype capacitors of two such materials, (Ba,Sr)TiO{sub 3} and PbZrO{sub 3}, have been fabricated in both thin film and bulk ceramic form. The influence of fabrication conditions on dielectric properties has been studied. Initial studies have demonstrated the viability of perovskite ferroelectrics for next-generation capacitor components.

Auciello, O. H.; Baldo, P.; Baumann, P.; Erck, R. A.; Giumarra, J.; Im, J.; Kaufman, D. Y.; Lanagan, M. T.; Pan, M. J.; Streiffer, S. K.; Zebrowski, J.

1999-08-10T23:59:59.000Z

292

Microstructural evolution in adiabatic shear bands of copper at high strain rates: Electron backscatter diffraction characterization  

SciTech Connect

The microstructural evolution of adiabatic shear bands in annealed copper with different large strains at high strain rates has been investigated by electron backscatter diffraction. The results show that mechanical twinning can occur with minimal contribution to shear localization under dynamic loading. Elongated ultrafine grains with widths of 100-300 nm are observed during the evolution of the adiabatic shear bands. A rotational dynamic recrystallization mechanism is proposed to explain the formation of the elongated ultrafine grains. - Highlights: Black-Right-Pointing-Pointer The microstructural evolution of ASB is studied by electron backscatter diffraction. Black-Right-Pointing-Pointer Twinning can occur in ASB while the contribution to shear localization is slight. Black-Right-Pointing-Pointer Elongated ultrafine grains are observed during the evolution process of ASB. Black-Right-Pointing-Pointer A possible mechanism is proposed to explain the microstructure evolution of ASB.

Tang Lin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Chen Zhiyong, E-mail: czysh@netease.com [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Zhan Congkun; Yang Xuyue; Liu Chuming [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Cai Hongnian [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2012-02-15T23:59:59.000Z

293

Microsoft Word - Extreme Electron Correlation in the Strange Metal Phase of High  

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

October 2011 October 2011 An exemplary fit of ARPES data using the ECFL theory. In this fit, the very wide energy of the data are fit including the rising background, thanks to the "caparison factor" of the ECFL theory. Extreme Electron Correlation in the Strange Metal Phase of High- temperature Superconductors High-temperature superconductors are known for their "strange metal phase," which presents a rich but strange set of phenomena that challenge understanding. A requirement for building a correct theoretical model of high temperature superconductors is that this strange metallic phase be explained first. One of the defining characteristics of the strange metal phase is the anomalous line shapes measured by angle resolved photoelectron

294

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners  

DOE Patents (OSTI)

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

Thode, Lester E. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

295

Solar wind suprathermal electron Stahl widths across high-speed stream structures  

SciTech Connect

Suprathermal electrons (100-1500 eV) observed in the solar wind typically show a strahl distribution, that is, a beam directed away from the Sun along the magnetic field direction. The strahl width observed at 1 AU is highly variable, ranging from 10-70 degrees. The obsenred finite width of the strahl results from the competition between beam focusing as the interplanetary magnetic field strength drops with distance from the Sun, and pitch-angle scattering as the beam interacts with the solar wind plasma in transit from the sun. Here we examine strahl width, observed with ACE SWEPAM across high-speed stream structures to investigate variations in electron scattering as a function of local plasma characteristics. We find that narrow strahls (less than 20 degrees wide), indicating reduced scattering, are observed within high-speed streams. Narrow strahls are also observed in both very low temperature solar wind, in association with ICMEs. Case studies of high-speed streams typically show the strahl narrowing at the leading edge of the stream. In some cases, the strahl narrows at the reverse shock or pressure wave, in other cases at the stream interface. The narrowing can either occur discontinuously or gradually over a period of hours. Within the high-speed wind, the strahl remains narrow for a period of hours to days, and then gradually broadens. The strahl width is roughly constant at all energies across these structures. For some fraction of high-speed streams, counterstreaming is associated with passage of the corotating interaction region. In these cases, we find the widths of the two counterstreaming beams frequently differ by more than 40 degrees. This dramatic difference in strahl width contrasts with observations in the solar wind as a whole, in which counterstreaming strahls typically differ in width by less than 20 degrees.

Skoug, Ruth M [Los Alamos National Laboratory; Steinberg, John T [Los Alamos National Laboratory; Goodrich, Katherine A [Los Alamos National Laboratory; Anderson, Brett R [DARTMUTH UNIV.

2011-01-03T23:59:59.000Z

296

Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons  

SciTech Connect

The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

Thieberger T.; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Minty, M.; Miller, T.; Montag, C.; Pikin, A.

2012-04-15T23:59:59.000Z

297

On information-provided monitoring of geodynamic processes in the Kuznetsk Coal Basin in the conditions of highly intensive sub-soil usage  

Science Conference Proceedings (OSTI)

It is shown that formation of underground hollows of the Kuznetsk Coal Basin (Kuzbass), induced by opencut and underground mining has reached an intensity of 1.3-1.5 million m{sup 3}/day. In the conditions of high concentration of mines and open-cuts in small areas, a regional monitoring network is required in view of a generated geomechanical space, hazardous in geodynamic manifestations. A developed information support of this network is presented, including information models of a geological environment and database obtained from instrumental observations on geomechanical processes. The equations of connection between structural and strength characteristics of rocks, their metamorphization grade and occurrence depth are given for five geological-tectonic zones of the Kuzbass as a way of prediction of their properties.

Oparin, V.N.; Potapov, V.P.; Tanaino, A.S. [Russian Academy of Science, Novosibirsk (Russian Federation). Inst. of Mining

2006-09-15T23:59:59.000Z

298

,,,"Incandescent","Standard Fluorescent","Compact Fluorescent","High-Intensity Discharge","Halogen"  

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

B39. Lighting Equipment, Floorspace, 1999" B39. Lighting Equipment, Floorspace, 1999" ,"Total Floorspace (million square feet)" ,"All Buildings","All Lit Buildings","Lighting Equipment (more than one may apply)" ,,,"Incandescent","Standard Fluorescent","Compact Fluorescent","High-Intensity Discharge","Halogen" "All Buildings ................",67338,64321,38156,60344,20666,19223,17926 "Building Floorspace" "(Square Feet)" "1,001 to 5,000 ...............",6774,5859,2946,5154,738,245,600 "5,001 to 10,000 ..............",8238,7464,4047,6722,1108,663,991 "10,001 to 25,000 .............",11153,10393,6055,9815,1759,1701,1996 "25,001 to 50,000 .............",9311,9053,5004,8344,2296,2224,1611

299

Magnetic lens apparatus for a low-voltage high-resolution electron microscope  

DOE Patents (OSTI)

A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

Crewe, Albert V. (Palos Park, IL)

1996-01-01T23:59:59.000Z

300

Electronic Properties of Iron Arsenic High Temperature Superconductors Revealed by Angle Resolved Photoemission Spectroscopy (ARPES)  

Science Conference Proceedings (OSTI)

We present an overview of the electronic properties of iron arsenic high temperature superconductors with emphasis on low energy band dispersion, Fermi surface and superconducting gap. ARPES data is compared with full-potential linearized plane wave (FLAPW) calculations. We focus on single layer NdFe-AsO{sub 0.9}F{sub 0.1} (R1111) and two layer Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} (B122) compounds. We find general similarities between experimental data and calculations in terms of character of Fermi surface pockets, and overall band dispersion. We also find a number of differences in details of the shape and size of the Fermi surfaces as well as the exact energy location of the bands, which indicate that magnetic interaction and ordering significantly affects the electronic properties of these materials. The Fermi surface consists of several hole pockets centered at {tau} and electron pockets located in zone corners. The size and shape of the Fermi surface changes significantly with doping. Emergence of a coherent peak below the critical temperature T{sub c} and diminished spectral weight at the chemical potential above T{sub c} closely resembles the spectral characteristics of the cuprates, however the nodeless superconducting gap clearly excludes the possibility of dwave order parameter. Instead it points to s-wave or extended s-wave symmetry of the order parameter.

Valla, T.; Liu, C.; Kondo, T.; Palczewski, A.D.; Samolyuk, G.D.; Lee, Y.; Tillman, M.E.; Ni, N.; Muna, E.D.; Gordon, R.; Santander-Syro, A.F.; Bud’ko, S.L.; McChesney, J.L.; Rotenberg, E.; Fedorov, A.V.; Copie, O.; Tanatar, M.A.; Martin, C.; Harmon, B.N.; Canfield, P.C.; Prozorov, R.; Schmalian, J.; Kaminski, A.

2009-06-15T23:59:59.000Z

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


301

Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes  

DOE Patents (OSTI)

Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

Crewe, Albert V. (Dune Acres, IN)

2000-01-01T23:59:59.000Z

302

Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics  

SciTech Connect

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.

Lowe, K.T.

2005-10-07T23:59:59.000Z

303

Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics  

SciTech Connect

The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.

Lowe, K.T.

2005-10-07T23:59:59.000Z

304

Absolute intensity calibration of flat-field space-resolved extreme ultraviolet spectrometer using radial profiles of visible and extreme ultraviolet bremsstrahlung continuum emitted from high-density plasmas in Large Helical Device  

Science Conference Proceedings (OSTI)

A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 A is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n{sub e}{>=} 10{sup 14} cm{sup -3}) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.

Dong Chunfeng; Wang Erhui [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); Morita, Shigeru; Goto, Motoshi [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); National Institute for Fusion Science, Toki 509-5292, Gifu (Japan)

2011-11-15T23:59:59.000Z

305

Reduction of Edge Localized Mode Intensity on DIII-D by On-demand triggering with High Frequency Pellet Injection and Implications for ITER  

Science Conference Proceedings (OSTI)

The injection of small deuterium pellets at high repetition rates up to 12 the natural edge localized mode (ELM) frequency has been used to trigger high-frequency ELMs in otherwise low natural ELM frequency H-mode deuterium discharges in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. The resulting pellet-triggered ELMs result in up to 12 lower energy and particle fluxes to the divertor than the natural ELMs. The plasma global energy confinement and density are not strongly affected by the pellet perturbations. The plasma core impurity density is strongly reduced with the application of the pellets. These experiments were performed with pellets injected from the low field side pellet in plasmas designed to match the ITER baseline configuration in shape and normalized operation with input heating power just above the H-mode power threshold. Nonlinear MHD simulations of the injected pellets show that destabilization of ballooning modes by a local pressure perturbation is responsible for the pellet ELM triggering. This strongly reduced ELM intensity shows promise for exploitation in ITER to control ELM size while maintaining high plasma purity and performance.

Baylor, Larry R [ORNL; Commaux, Nicolas JC [ORNL; Jernigan, T. C. [Oak Ridge National Laboratory (ORNL); Meitner, Steven J [ORNL; Combs, Stephen Kirk [ORNL; Isler, Ralph C [ORNL; Unterberg, Ezekial A [ORNL; Brooks, N. H. [General Atomics, San Diego; Evans, T.E. [General Atomics, San Diego; Leonard, A. W. [General Atomics; Osborne, T. H. [General Atomics; Parks, P. B. [General Atomics; Snyder, P. B. [General Atomics; Strait, E. J. [General Atomics; Fenstermacher, M. E. [Lawrence Livermore National Laboratory (LLNL); Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Moyer, R.A. [University of California, San Diego; Loarte, A. [ITER Organization, Cadarache, France; Huijsmans, G.T.A. [ITER Organization, Saint Paul Lez Durance, France; Futantani, S. [ITER Organization, Saint Paul Lez Durance, France

2013-01-01T23:59:59.000Z

306

Accelerators for Intensity Frontier Research  

SciTech Connect

In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

Derwent, Paul; /Fermilab

2012-05-11T23:59:59.000Z

307

Intense low energy positron beams  

Science Conference Proceedings (OSTI)

Intense positron beams are under development or being considered at several laboratories. Already today a few accelerator based high intensity, low brightness e{sup +} beams exist producing of the order of 10{sup 8} {minus} 10{sup 9} e{sup +}/sec. Several laboratories are aiming at high intensity, high brightness e{sup +} beams with intensities greater than 10{sup 9} e{sup +}/sec and current densities of the order of 10{sup 13} {minus} 10{sup 14} e{sup +} sec{sup {minus}} {sup 1}cm{sup {minus}2}. Intense e{sup +} beams can be realized in two ways (or in a combination thereof) either through a development of more efficient B{sup +} moderators or by increasing the available activity of B{sup +} particles. In this review we shall mainly concentrate on the latter approach. In atomic physics the main trust for these developments is to be able to measure differential and high energy cross-sections in e{sup +} collisions with atoms and molecules. Within solid state physics high intensity, high brightness e{sup +} beams are in demand in areas such as the re-emission e{sup +} microscope, two dimensional angular correlation of annihilation radiation, low energy e{sup +} diffraction and other fields. Intense e{sup +} beams are also important for the development of positronium beams, as well as exotic experiments such as Bose condensation and Ps liquid studies.

Lynn, K.G.; Jacobsen, F.M.

1993-12-31T23:59:59.000Z

308

Intense ion beam generator  

DOE Patents (OSTI)

Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

Humphries, Jr., Stanley (Ithaca, NY); Sudan, Ravindra N. (Ithaca, NY)

1977-08-30T23:59:59.000Z

309

High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets  

SciTech Connect

This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.

Scalettar, Richard T.; Pickett, Warren E.

2004-07-01T23:59:59.000Z

310

High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets  

SciTech Connect

This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

Richard T. Scalettar; Warren E. Pickett

2005-08-02T23:59:59.000Z

311

Electronic imaging system and technique  

SciTech Connect

A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

Bolstad, Jon O. (Idaho Falls, ID)

1987-01-01T23:59:59.000Z

312

Electronic imaging system and technique  

DOE Patents (OSTI)

A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

Bolstad, J.O.

1984-06-12T23:59:59.000Z

313

A model for the critical voltage for electrical degradation of GaN high electron mobility transistors  

E-Print Network (OSTI)

We have found that there is a critical drain-to-gate voltage beyond which GaN high-electron mobility transistors start to degrade in electrical-stress experiments. The critical voltage depends on the detailed voltage biasing ...

Joh, Jungwoo

314

A picosecond time-resolved electron energy spectrometer based on Cerenkov radiation  

Science Conference Proceedings (OSTI)

The energy spectrum of relativistic electrons is an important characterization of high intensity laser-matter interactions. We present a technique that utilizes Cerenkov radiation to measure the time-resolved energy distribution of electrons. Electrons escaping from targets irradiated by high-intensity laser pulses were measured, demonstrating the feasibility of such a novel diagnostic. Limitations on the time resolution of this diagnostic are also discussed.

Elberson, Lee N.; Hill, Wendell T. III [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); Ping, Yuan; Shepherd, Ronnie L.; Patel, Pravesh K.; Mackinnon, Andrew J. [Lawrence Livermore National Laboratory, Livermore, California 94550-9234 (United States)

2009-02-15T23:59:59.000Z

315

The electron temperatures of SDSS high-metallicity giant extragalactic HII regions  

E-Print Network (OSTI)

Spectra of high-metallicity (12+log(O/H) > 8.2) HII regions where oxygen auroral lines are measurable in both the O+ and O++ zones, have been extracted from the Data Release 6 of the Sloan Digital Sky Survey (SDSS). Our final sample consists of 181 SDSS spectra of HII regions in galaxies in the redshift range from ~0.025 to ~0.17. The t_2,O-t_3,O diagram is examined. In the SDSS HII regions, the electron temperature t_2,O is found to have a large scatter at a given value of the electron temperature t_3,O. The majority of the SDSS HII regions lie below the t_2,O-t_3,O relation derived for HII regions in nearby galaxies, i.e. the positions of the SDSS HII regions show a systematic shift towards lower t_2,O temperatures or/and towards higher t_3,O temperatures. The scatter and shift of the SDSS HII regions in the t_2,O-t_3,O diagram can be understood if they are composite nebulae excited by two or more ionizing sources of different temperatures.

Pilyugin, L S; Cedres, B; Thuan, T X

2009-01-01T23:59:59.000Z

316

Industrial Plant for Flue Gas Treatment with High Power Electron Accelerators  

SciTech Connect

Fossil fuel combustion leads to acidic pollutants, like SO2, NOx, HCl emission. Different control technologies are proposed however, the most popular method is combination of wet FGD (flue gas desulfurization) and SCR (selective catalytic reduction). First, using lime or limestone slurry leads to SO2 capture, and gypsum is a product. The second process where ammonia is used as reagent and nitrogen oxides are reduced over catalyst surface to gaseous nitrogen removes NOx. New advanced method using electron accelerators for simultaneous SO2 and NOx removal has been developed in Japan, the USA, Germany and Poland. Both pollutants are removed with high efficiency and byproduct can be applied as fertilizer. Two industrial plants have been already constructed. One in China and second in Poland, third one is under construction in Japan. Information on the Polish plant is presented in the paper. Plant has been constructed at Power Station Pomorzany, Szczecin (Dolna Odra Electropower Stations Group) and treats flue gases from two Benson boilers 60 MWe and 100 MWth each. Flow rate of the flue gas stream is equal to 270 000 Nm3/h. Four transformer accelerators, 700 keV electron energy and 260 kW beam power each were applied. With its 1.05 MW total beam power installed it is a biggest radiation facility over the world, nowadays. Description of the plant and results obtained has been presented in the paper.

Chmielewski, Andrzej G. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); University of technology, faculty of Process and Chemical Engineering, Warsaw (Poland); Tyminski, Bogdan; Zimek, Zbigniew; Pawelec, Andrzej [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Licki, Janusz [Institute of Atomic Energy, Swierk (Poland)

2003-08-26T23:59:59.000Z

317

CIM - compact intensity modulation.  

SciTech Connect

Compact intensity modulation (CIM), a new method to modulate the intensity of a neutron beam is demonstrated. CIM allows the production of arbitrary signals where the focus point can be chosen and changed without any constraints. A novel feature in this technique compared to spin echo techniques is that the neutron polarization is kept parallel or anti-parallel to the static fields during the passage through the magnetic fields and the beating pattern at the detector is produced by an amplitude modulation (AM) of the adiabatic RF-spin flippers rather than Larmor precession like in neutron spin echo (NSE) instruments; thus, the achievable contrast is very high and the instrument resolution can be changed very quickly. This gives the fascinating possibility at pulsed neutron sources to sweep the modulation frequency of the flippers in order to increase dynamic resolution range during the same neutron pulse.

Bleuel, M.; Lang, E.; Gahler, G.; Lal, J.; Intense Pulsed Neutron Source; Inst. Lau Langevin

2008-07-21T23:59:59.000Z

318

Imaging the geometrical structure of the H{sub 2}{sup +} molecular ion by high-order above-threshold ionization in an intense laser field  

Science Conference Proceedings (OSTI)

Using a frequency-domain theory, we demonstrate that an angle-resolved high-order above-threshold ionization (HATI) spectrum carries three pieces of important information: the fingerprint of the molecular wave function in the direct above-threshold-ionization amplitude, the geometrical structure of the molecule in the potential scattering between two plane waves, and the interaction between the ionized electron and the laser field, manifested in a phase factor associated with laser-assisted collisions. As a result all main interference features in the HATI spectrum can be physically explained. As an application it is pointed out that the skeleton structure of a molecule can be better imaged using lasers of higher frequencies.

Guo Yingchun [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Fu Panming; Wang Bingbing [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Yan Zongchao [Department of Physics, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, Canada E3B 5A3 (Canada); Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Gong Jiangbin [Department of Physics and Center of Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore)

2009-12-15T23:59:59.000Z

319

Space charge effect of the high intensity proton beam during the resonance extraction for the Mu2e experiment at Fermilab  

SciTech Connect

The proposed Mu2e experiment to search for direct {mu} {yields} e conversion at Fermilab plans slow, resonant extraction of a beam with 3 x 10{sup 12} protons from the Debuncher ring. Space charge of this high intensity beam is a critical factor, since it induces significant betatron tune spread and consequently affects resonance extraction processes, such as spill uniformity and beam losses. This study shows the multi-particle simulation results in the early stages of resonance extraction and spill uniformity in the presence of 2D and 3D space charge effects. We have presented the results of the third-integer resonance extraction in early stage for the Mu2e experiment in the presence of space charge effects. In order to track particles and to calculate self-consistent space charge effects, Synergia2 was used, which is capable of parallel computing. The space charge tune shift was computed and was reasonable value compared with the analytical calculation. Locations of the septum and Lambertson were chosen so that particles are kicked and extracted efficiently. The spill rates for with and without space charge effects were uniform, but should be improved for the early stage after the sextupole field ramping.

Park, Chong Shik; Amundson, James; Johnstone, John; Michelotti, Leo; Nagaslaev, Vladimir; Werkema, Steve; /Fermilab

2011-03-01T23:59:59.000Z

320

Higher Hydroclimatic Intensity with Global Warming  

Science Conference Proceedings (OSTI)

Because of their dependence on water, natural and human systems are highly sensitive to changes in the hydrologic cycle. The authors introduce a new measure of hydroclimatic intensity (HY-INT), which integrates metrics of precipitation intensity ...

F. Giorgi; E.-S. Im; E. Coppola; N. S. Diffenbaugh; X. J. Gao; L. Mariotti; Y. Shi

2011-10-01T23:59:59.000Z

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321

High-speed Imaging of the Electron-beam Based Additive ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Oak Ridge National Laboratory (ORNL) has been utilizing the Arcam electron beam melting (EBM) technology to additively manufacture ...

322

High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system  

Science Conference Proceedings (OSTI)

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20 deg. - 40 deg. from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system.

Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Doane, J.; Olstad, R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Henderson, M. [ITER Organization, CS90 046, 13067 St. Paul lez Durance Cedex (France)

2011-06-15T23:59:59.000Z

323

A Study of the Impacts of Vertical Diffusion on the Structure and Intensity of the Tropical Cyclones Using the High-Resolution HWRF System  

Science Conference Proceedings (OSTI)

The Hurricane Weather Research and Forecasting (HWRF) system was used in an idealized framework to gain a fundamental understanding of the variability in tropical cyclone (TC) structure and intensity prediction that may arise due to vertical ...

Sundararaman G. Gopalakrishnan; Frank Marks Jr.; Jun A. Zhang; Xuejin Zhang; Jian-Wen Bao; Vijay Tallapragada

2013-02-01T23:59:59.000Z

324

High-Resolution Observations and Model Simulations of the Life Cycle of an Intense Mesoscale Snowband over the Northeastern United States  

Science Conference Proceedings (OSTI)

This paper investigates the structural and dynamical evolution of an intense mesoscale snowband occurring 25–26 December 2002 over the northeastern United States. Dual-Doppler, wind profiler, aircraft, and water vapor observations in concert with ...

David R. Novak; Brian A. Colle; Sandra E. Yuter

2008-04-01T23:59:59.000Z

325

Electron emission and defect formation in the interaction of slow,highly charged ions with diamond surfaces  

DOE Green Energy (OSTI)

We report on electron emission and defect formation in theinteraction between slow (v~;0.3 vBohr) highly charged ions (SHCI) withinsulating (type IIa) and semiconducting (type IIb) diamonds. Electronemission induced by 31Pq+ (q=5 to 13), and 136Xeq+ (q=34 to 44) withkinetic energies of 9 kVxq increase linearly with the ion charge states,reaching over 100 electrons per ion for high xenon charge states withoutsurface passivation of the diamond with hydrogen. Yields from bothdiamond types are up to a factor of two higher then from reference metalsurfaces. Crater like defects with diameters of 25 to 40 nm are formed bythe impact of single Xe44+ ions. High secondary electron yields andsingle ion induced defects enable the formation of single dopant arrayson diamond surfaces.

Sideras-Haddad, E.; Shrivastava, S.; Rebuli, D.B.; Persaud, A.; Schneider, D.H.; Schenkel, T.

2006-05-31T23:59:59.000Z

326

Double pulse doped InGaAs/AlGaAs/GaAs pseudomorphic high-electron-mobility transistor heterostructures  

Science Conference Proceedings (OSTI)

Double pulse doped ({delta}-doped) InGaAs/AlGaAs/GaAs pseudomorphic high-electron-mobility transistor (HEMT) heterostructures were grown by molecular-beam epitaxy using a multiwafer technological system. The room-temperature electron mobility was determined by the Hall method as 6550 and 6000 cm{sup 2}/(V s) at sheet electron densities of 3.00 x 10{sup 12} and 3.36 x 10{sup 12} cm{sup -2}, respectively. HEMT heterostructures fabricated in a single process feature high uniformity of structural and electrical characteristics over the entire area of wafers 76.2 mm in diameter and high reproducibility of characteristics from process to process.

Egorov, A. Yu., E-mail: anton@beam.ioffe.ru; Gladyshev, A. G.; Nikitina, E. V.; Denisov, D. V.; Polyakov, N. K.; Pirogov, E. V.; Gorbazevich, A. A. [Russian Academy of Sciences, St. Petersburg Physics and Technology Center for Research and Education (Russian Federation)

2010-07-15T23:59:59.000Z

327

A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers  

Science Conference Proceedings (OSTI)

We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of {mu} A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance.

Barcellan, L.; Carugno, G. [INFN Section, Padua (Italy); Berto, E.; Galet, G.; Galeazzi, G. [Department of Physics, University of Padua (Italy); Borghesani, A. F. [INFN Section, Padua (Italy); CNISM Unit, Department of Physics, University of Padua (Italy)

2011-09-15T23:59:59.000Z

328

Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope  

DOE Patents (OSTI)

A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

de Jonge, Niels (Oak Ridge, TN)

2010-08-17T23:59:59.000Z

329

Low-energy electron and low-energy positron holography  

Science Conference Proceedings (OSTI)

We demonstrate holographic reconstruction using low-energy electron-diffraction (LEED) and low-energy positron-diffraction (LEPD) intensity spectra. Calculated LEED and LEPD intensity spectra from a multiple-scattering method are inverted to produce high-fidelity images of near-neighbor atoms whose positions are measured from an adatom. We show that low-energy positron diffraction is better suited for holographic reconstruction because positron scattering in solids is weaker than that of electrons.

Tong, S.Y.; Huang, H.; Guo, X.Q. (Laboratory for Surface Studies and Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201 (United States))

1992-12-21T23:59:59.000Z

330

L1, Formation of Structural Defects in AlGaN/GaN High Electron ...  

Science Conference Proceedings (OSTI)

Transmission electron microscope (TEM) cross sectional image has shown that electrical degradation is closely related to structural damage in the GaN cap and  ...

331

Photo-stimulated low electron temperature high current diamond film field emission cathode  

DOE Patents (OSTI)

An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

Shurter; Roger Philips (Los Alamos, NM), Devlin; David James (Santa Fe, NM), Moody; Nathan Andrew (Los Alamos, NM), Taccetti; Jose Martin (Santa Fe, NM), Russell; Steven John (Los Alamos, NM)

2012-07-24T23:59:59.000Z

332

Stretchable form of single crystal silicon for high performance electronics on rubber substrates  

DOE Patents (OSTI)

The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

University of Illinois (Urbana, IL)

2009-04-21T23:59:59.000Z

333

Stretchable form of single crystal silicon for high performance electronics on rubber substrates  

DOE Patents (OSTI)

The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

Rogers, John A. (Champaign, IL); Khang, Dahl-Young (Seoul, KR); Sun, Yugang (Naperville, IL); Menard, Etienne (Durham, NC)

2012-06-12T23:59:59.000Z

334

High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels  

Science Conference Proceedings (OSTI)

The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

1991-09-01T23:59:59.000Z

335

Effect of buffer structures on AlGaN/GaN high electron mobility transistor reliability  

Science Conference Proceedings (OSTI)

AlGaN/GaN high electron mobility transistors (HEMTs) with three different types of buffer layers, including a GaN/AlGaN composite layer, or 1 or 2 lm GaN thick layers, were fabricated and their reliability compared. The HEMTs with the thick GaN buffer layer showed the lowest critical voltage (Vcri) during off-state drain step-stress, but this was increased by around 50% and 100% for devices with the composite AlGaN/GaN buffer layers or thinner GaN buffers, respectively. The Voff - state for HEMTs with thin GaN and composite buffers were 100 V, however, this degraded to 50 60V for devices with thick GaN buffers due to the difference in peak electric field near the gate edge. A similar trend was observed in the isolation breakdown voltage measurements, with the highest Viso achieved based on thin GaN or composite buffer designs (600 700 V), while a much smaller Viso of 200V was measured on HEMTs with the thick GaN buffer layers. These results demonstrate the strong influence of buffer structure and defect density on AlGaN/GaN HEMT performance and reliability.

Liu, L. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

2012-01-01T23:59:59.000Z

336

How Electron Spectroscopy with Synchrotron Light Can Help Us Understand High-Tc Superconductivity and Other Complex States of Matter  

SciTech Connect

All the physical, chemical, and mechanical properties of materials are controlled by electrons that occupy the highest energy levels in solids, those near the Fermi energy. Many techniques were developed to study those electrons, leading to the great successes of condensed matter physics. Newer and complex materials, such as the high-temperature superconductors, tend to exhibit very large anisotropies in their physical properties, requiring a more detailed knowledge of the behavior of electrons not only as a function of their energy, but also their momentum. Angle-resolved photoemission can contribute to our understanding by providing a great deal of information on many of the momentum-dependent properties of electrons and their interactions. In this talk, I will present a brief overview of how a long-term and focused collaboration between scientists at Argonne and other institutions has contributed to making angle-resolved photoemissions a most useful tool in the study of complex states of matter.

Campuzano, Juan Carlos [University of Illinois, Chicago

2012-03-07T23:59:59.000Z

337

EXTRACTION OF HIGHLY CHARGED AU IONS FROM A MULTIAMPHERE ELECTRON BEAM EBIS AT BNL.  

DOE Green Energy (OSTI)

Excellent progress has been made in the operation of the BNL Electron Beam Ion Source (EBIS), which is a prototype for an EBIS that could meet requirements for a RHIC preinjector. We have achieved very stable operation of the electron beam at 10 A through the EBIS trap. Ion injection of low charge gold ions from a LEVA [1] ion source and subsequent extraction of these ions with most probable charge state AU{sup 34+} has been demonstrated with electron beams up to 8A. The total ion charge for gold measured on current transformer at the EBIS exit was 55nC after a 30ms confinement period. This corresponds to {approx}85% of the theoretical ion trap capacity and exceeds our goal of 50% neutralization. The collected ion charge is proportional to the electron current and the gold charge state scales with the electron current density. Details of the EBIS configuration, total charge measurements, and TOF spectra are given.

BEEBE,E.N.; ALESSI,J.G.; GOULD,O.; GRAHAM,D.; KPONOU,A.; PIKIN,A.; PRELEC,K.; RITTER,J.

2001-09-02T23:59:59.000Z

338

A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers  

E-Print Network (OSTI)

We report on the design of a new type of electron gun to be used for experiments of infrared emission spectroscopy of rare gas excimers. It is based on a filament heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply. The filament current is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. Our experiment requires that the charge injection is pulsed and constant and stable in time. This electron gun can deliver several tens of nC per pulse of electrons of energy up to $100\\,$keV into the sample cell. This new design eliminates ripples in the emission current and ensures up to 12 hrs of stable performance.

Barcellan, L; Carugno, G; Galet, G; Galeazzi, G; Borghesani, A F

2011-01-01T23:59:59.000Z

339

High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States); Bender, H. A.; Wilcox, N. S. [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

2010-01-15T23:59:59.000Z

340

High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

2010-01-01T23:59:59.000Z

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


341

Phase II Study of Long-Term Androgen Suppression With Bevacizumab and Intensity-Modulated Radiation Therapy (IMRT) in High-Risk Prostate Cancer  

Science Conference Proceedings (OSTI)

Purpose: We report a Phase II trial assessing the acute and late toxicities of intensity-modulated radiation therapy (IMRT), long-term androgen suppression (LTAS), and bevacizumab in patients with high-risk localized prostate cancer. Methods and Materials: We treated 18 patients with LTAS with bicalutamide and goserelin in combination with bevacizumab and IMRT. Bevacizumab (10 mg/kg every 2 weeks) was administered for the first 16 weeks, and 15 mg/kg was then given every 3 weeks for 12 additional weeks, with an IMRT dose of 77.9 Gy to the prostate, 64.6 Gy to the seminal vesicles, and 57 Gy to the pelvic lymph nodes. Patients were eligible if they had clinical stage T2b to T4, a Gleason sum score of 8 to 10, or a prostate- specific antigen level of 20ng/mL or greater. The primary endpoint of the study was evaluation of acute and late toxicities. Results: The median age was 69 years, with a median pretreatment prostate-specific antigen level of 12.5 ng/mL and Gleason score of 8. The pretreatment clinical stage was T1c in 4 patients, T2 in 11, and T3 in 3. All patients completed IMRT with median follow-up of 34 months (range, 28-40 months) The most common Grade 2 or higher toxicities were hypertension (61% of patients with Grade 2 and 11% with Grade 3), proteinuria (28% with Grade 2 and 6% with Grade 3), and leucopenia (28% with Grade 2). No Grade 4 or higher acute toxicities were reported. Late toxicities included proctitis (6% of patients with Grade 2 and 11% with Grade 3), rectal bleeding (6% with Grade 2 and 11% with Grade 3), hematuria (6% with Grade 2), proteinuria (17% with Grade 2), hyponatremia (6% with Grade 3), cystitis (6% with Grade 3), and urinary retention (6% with Grade 2 and 11% with Grade 3). Grade 4 prostatitis occurred in 1 patient (6%). Conclusions: Bevacizumab does not appear to exacerbate the acute effects of IMRT. Late toxicities may have been worsened with this regimen. Further investigations of bevacizumab with LTAS and IMRT should be performed cautiously.

Vuky, Jacqueline, E-mail: vukyja@ohsu.edu [Section of Community Hematology/Oncology, Knight Cancer Institute, Oregon Health Sciences University, Portland, OR (United States); Pham, Huong T. [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States); Warren, Sarah; Douglass, Erika [Benaroya Research Institute, Virginia Mason Medical Center, Seattle, WA (United States); Badiozamani, Kasra [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States); Madsen, Berit; Hsi, Alex [Peninsula Cancer Center, Poulsbo, WA (United States); Song Guobin [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States)

2012-03-15T23:59:59.000Z

342

International Journal of High Speed Electronics and Systems Vol. 16, No 2 (2006) pp. 559-566  

E-Print Network (OSTI)

International Journal of High Speed Electronics and Systems Vol. 16, No 2 (2006) pp. 559-566 © World Scientific Publishing Company FEASIBILITY OF AN OPTICAL FREQUENCY MODULATION SYSTEM FOR FREE, SUNY, Stony Brook, NY 11794-2350, USA We consider a free-space communication system based on optical

Luryi, Serge

343

SnO2 functionalized AlGaN/GaN high electron mobility transistor for hydrogen sensing applications  

E-Print Network (OSTI)

. Nanocrystalline indium oxide-doped tin oxide thin film as low temperature hydrogen sensor. Sensors and Actuators B Available online 1 May 2012 Keywords: Hydrogen sensor High electron mobility transistors (HEMT) Tin oxide rights reserved. 1. Introduction Hydrogen is a clean, renewable, and sustainable energy carrier

Florida, University of

344

Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma  

SciTech Connect

Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2012-07-15T23:59:59.000Z

345

Low-energy, high-current, ion source with cold electron emitter  

SciTech Connect

An ion source based on a two-stage discharge with electron injection from a cold emitter is presented. The first stage is the emitter itself, and the second stage provides acceleration of injected electrons for gas ionization and formation of ion flow (<20 eV, 5 A dc). The ion accelerating system is gridless; acceleration is accomplished by an electric field in the discharge plasma within an axially symmetric, diverging, magnetic field. The hollow cathode electron emitter utilizes an arc discharge with cathode spots hidden inside the cathode cavity. Selection of the appropriate emitter material provides a very low erosion rate and long lifetime.

Vizir, A. V.; Oks, E. M. [High Current Electronics Institute, Russian Academy of Sciences, Tomsk 634055 (Russian Federation); State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Shandrikov, M. V.; Yushkov, G. Yu. [High Current Electronics Institute, Russian Academy of Sciences, Tomsk 634055 (Russian Federation)

2012-02-15T23:59:59.000Z

346

High-energy electron-helium scattering in a Nd:YAG laser field  

SciTech Connect

We report measurements of the scattering of electrons by helium atoms in the presence of 1.17 eV photons from a Nd:YAG laser. The incident energy of the electrons was in the range 50-350 eV, and the polarization of the laser was arranged to be parallel to electrons scattered through 135 deg. Energy-shifted peaks corresponding both to one- and two-photon emission were observed. Calculations using the Kroll-Watson approximation are perfectly consistent with the data.

Harak, B. A. de [Physics Department, Illinois Wesleyan University, P.O. Box 2900, Bloomington, Illinois 61702-2900 (United States); Ladino, L.; MacAdam, K. B.; Martin, N. L. S. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

2011-02-15T23:59:59.000Z

347

Analysis, design, and experiments of a high-power-factor electronic ballast  

SciTech Connect

A charge pump power-factor-correction (CPPFC) converter is first derived, and its unity power factor condition is then reviewed. A single-stage power-factor-correction electronic ballast using the charge pump concept is analyzed. The design criteria are derived to optimize the electronic ballast based on the steady-state analysis. Constant lamp power operations associated with its control are also discussed. Large signal simulation and experimental results verify the theoretical analysis. It is shown that the designed electronic ballast has 0.995 power factor and 5% total harmonic distortion (THD) with lamp power variation within {+-}15% when the line input voltage changes {+-}10%.

Qian, J.; Lee, F.C. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Yamauchi, T. [Matsushita Electric Works, Inc., Woburn, MA (United States)

1998-05-01T23:59:59.000Z

348

OECD energy intensity  

Science Conference Proceedings (OSTI)

to examine OECD countries' energy intensity levels (i.e., the ratio of energy ... steady-state or long-run distribution of energy intensity for the Organisation of ...

349

Elimination of two atomic electrons by a single high energy photon  

Science Conference Proceedings (OSTI)

This report discusses the following topics: mechanism of two-electron photoionization; multiple photoionization near inner shell thresholds; double ionization accompanying compton-effect; and the investigation of secondary photon emission in coincidence with double charged ion production.

Amusia, M.Y. [Argonne National Lab., IL (United States); Ioffe, A.F. [AN SSSR, Leningrad (Russian Federation). Fiziko-Tekhnicheskij Inst.

1993-12-31T23:59:59.000Z

350

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge  

SciTech Connect

Recently, an anomalous evolution of argon metastable density with plasma discharge power (electron density) was reported [A. M. Daltrini, S. A. Moshkalev, T. J. Morgan, R. B. Piejak, and W. G. Graham, Appl. Phys. Lett. 92, 061504 (2008)]. Although the importance of the metastable atom and its density has been reported in a lot of literature, however, a basic physics behind the anomalous evolution of metastable density has not been clearly understood yet. In this study, we investigated a simple global model to elucidate the underlying physics of the anomalous evolution of argon metastable density with the electron density. On the basis of the proposed simple model, we reproduced the anomalous evolution of the metastable density and disclosed the detailed physics for the anomalous result. Drastic changes of dominant mechanisms for the population and depopulation processes of Ar metastable atoms with electron density, which take place even in relatively low electron density regime, is the clue to understand the result.

Park, Min; Chang, Hong-Young [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, Shin-Jae; Kim, Jung-Hyung [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon, 305-306 (Korea, Republic of); Shin, Yong-Hyeon

2011-10-15T23:59:59.000Z

351

High Throughput Ab initio Modeling of Charge Transport for Bio-Molecular-Electronics  

E-Print Network (OSTI)

resonant tunneling diode (RTD) for electronic circuitstructure to perform as an RTD. A resonant level lies closecharacteristics of an RTD. The I-V has a peak magnitude of 4

Bruque, Nicolas A.

2009-01-01T23:59:59.000Z

352

Magnetic-field shielding of satellites from high-energy-electron environments  

Science Conference Proceedings (OSTI)

Magnet configurations are found that limit the 6-MeV electrons threatening satellite electronics to <1% of the incident flux. Successful configurations of permanent magnets and electromagnets require magnetic energies of {approximately}8 to 12 kJ to protect each liter of electronics volume. The fundamental strength of materials leads to a required minimum mass of {approximately}48 to 64 kg/liter to support the magnetic pressure. With the electronics requiring {approximately}5 liters, several hundred kilograms are needed for this support. Except for protecting small apertures, magnetic shielding provides little, if any, advantage over that obtained by coating with an equivalent mass using traditional methods. 7 refs., 9 figs., 1 tab.

Vittitoe, C.N.

1990-05-01T23:59:59.000Z

353

Coulomb Distortion Effects for (e,e'p) Reactions at High Electron Energy  

E-Print Network (OSTI)

We report a significant improvement of an approximate method of including electron Coulomb distortion in electron induced reactions at momentum transfers greater than the inverse of the size of the target nucleus. In particular, we have found a new parametrization for the elastic electron scattering phase shifts that works well at all electron energies greater than 300 $MeV$. As an illustration, we apply the improved approximation to the $(e,e'p)$ reaction from medium and heavy nuclei. We use a relativistic ``single particle'' model for $(e,e'p)$ as as applied to $^{208}Pb(e,e'p)$ and to recently measured data at CEBAF on $^{16}O(e,e'p)$ to investigate Coulomb distortion effects while examining the physics of the reaction.

K. S. Kim; L. E. Wright

1999-07-09T23:59:59.000Z

354

Density effect on relativistic electron beams in a plasma fiber  

Science Conference Proceedings (OSTI)

Intense short-petawatt-laser driven relativistic electron beams in a hollow high-Z plasma fiber embedded in low-Z plasmas of different densities are studied. When the plasma is of lower density than the hollow fiber, resistive filamentation of the electron beam is observed. It is found that the electron motion and the magnetic field are highly correlated with tens of terahertz oscillation frequency. Depending on the material property around the hollow fiber and the plasma density, the beam electrons can be focused or defocused as it propagates in the plasma. Relativistic electron transport and target heating are also investigated.

Zhou, C. T.; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wang, X. G. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wu, S. Z. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Cai, H. B. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Wang, F. [Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2010-11-15T23:59:59.000Z

355

3-D readout-electronics packaging for high-bandwidth massively paralleled imager  

DOE Patents (OSTI)

Dense, massively parallel signal processing electronics are co-packaged behind associated sensor pixels. Microchips containing a linear or bilinear arrangement of photo-sensors, together with associated complex electronics, are integrated into a simple 3-D structure (a "mirror cube"). An array of photo-sensitive cells are disposed on a stacked CMOS chip's surface at a 45.degree. angle from light reflecting mirror surfaces formed on a neighboring CMOS chip surface. Image processing electronics are held within the stacked CMOS chip layers. Electrical connections couple each of said stacked CMOS chip layers and a distribution grid, the connections for distributing power and signals to components associated with each stacked CSMO chip layer.

Kwiatkowski, Kris (Los Alamos, NM); Lyke, James (Albuquerque, NM)

2007-12-18T23:59:59.000Z

356

Electron beam lithography at 10keV using an epoxy based high resolution negative resist  

Science Conference Proceedings (OSTI)

The behaviour of a new epoxy based resist (mr-EBL 6000.1 XP) as a negative resist for e-beam lithography is presented. We demonstrate that it is possible to define sub-100nm patterns when irradiating thin (120nm) layers of resist with a 10keV electron ... Keywords: EBL, Nanopatterning, Negative resist, Polymer technology

C. Martin; G. Rius; A. Llobera; A. Voigt; G. Gruetzner; F. Pérez-Murano

2007-05-01T23:59:59.000Z

357

Preparations for a high gradient inverse free electron laser experiment at Brookhaven national laboratory  

SciTech Connect

Preparations for an inverse free electron laser experiment at Brookhaven National Laboratory's Accelerator Test Facilty are presented. Details of the experimental setup including beam and laser transport optics are first discussed. Next, the driving laser pulse structure is investigated and initial diagnostics are explored and compared to simulations. Finally, planned improvements to the experimental setup are discussed.

Duris, J.; Li, R. K.; Musumeci, P.; Sakai, Y.; Threlkeld, E.; Williams, O.; Fedurin, M.; Kusche, K.; Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V. [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Accelerator Test Facility, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

2012-12-21T23:59:59.000Z

358

High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators  

DOE Patents (OSTI)

A mixture of epoxy resins such as a semi-solid triglycidyl ether of tris (hydroxyphenyl) methane and a low viscosity bisphenol A glycidyl ether and a cationic photoinitiator such as a diaryliodonium salt is cured by irradiating with a dosage of electron beams from about 50 to about 150 kGy, forming a cross-linked epoxy resin polymer.

Janke, Christopher J. (Powell, TN); Lopata, Vincent J. (Manitoba, CA); Havens, Stephen J. (Knoxville, TN); Dorsey, George F. (Farragut, TN); Moulton, Richard J. (Lafayette, CA)

1999-01-01T23:59:59.000Z

359

High-current electron beam generation by a pulsed hollow cathode  

Science Conference Proceedings (OSTI)

In this paper the parameters of a hollow-cathode electron source and the generatedelectron beam are presented. A gas puff valve is used to provide a sharp pressure gradient between the cathode cavity and the accelerating gap. To produce the plasma inside the hollow cathode we used a pulse forming network (10 kV

J. Z. Gleizer; A. Krokhmal; Ya. E. Krasik; J. Felsteiner

2002-01-01T23:59:59.000Z

360

Characteristics of InGaP/InGaAs pseudomorphic high electron mobility transistors with triple delta-doped sheets  

Science Conference Proceedings (OSTI)

Fundamental and insightful characteristics of InGaP/InGaAs double channel pseudomorphic high electron mobility transistors (DCPHEMTs) with graded and uniform triple {delta}-doped sheets are coomprehensively studied and demonstrated. To gain physical insight, band diagrams, carrier densities, and direct current characteristics of devices are compared and investigated based on the 2D semiconductor simulator, Atlas. Due to uniform carrier distribution and high electron density in the double InGaAs channel, the DCPHEMT with graded triple {delta}-doped sheets exhibits better transport properties, higher and linear transconductance, and better drain current capability as compared with the uniformly triple {delta}-doped counterpart. The DCPHEMT with graded triple {delta}-doped structure is fabricated and tested, and the experimental data are found to be in good agreement with simulated results.

Chu, Kuei-Yi [National Cheng-Kung University, Institute of Microelectronics, Department of Electrical Engineering (China); Chiang, Meng-Hsueh, E-mail: mhchiang@niu.edu.tw; Cheng, Shiou-Ying, E-mail: sycheng@niu.edu.tw [National II an University, Department of Electronic Engineering (China); Liu, Wen-Chau [National Cheng-Kung University, Institute of Microelectronics, Department of Electrical Engineering (China)

2012-02-15T23:59:59.000Z

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


361

Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams  

DOE Patents (OSTI)

Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

Hawryluk, A.M.; Ceglio, N.M.

1991-04-10T23:59:59.000Z

362

Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams  

DOE Patents (OSTI)

Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

Hawryluk, Andrew M. (Modesto, CA); Ceglio, Natale M. (Livermore, CA)

1993-01-01T23:59:59.000Z

363

High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions  

SciTech Connect

A large area plasma source based on 12 multi-dipolar ECR plasma cells arranged in a 3 x 4 matrix configuration was built and optimized for silicon etching by negative ions. The density ratio of negative ions to electrons has exceeded 300 in Ar/SF{sub 6} gas mixture when a magnetic filter was used to reduce the electron temperature to about 1.2 eV. Mass spectrometry and electrostatic probe were used for plasma diagnostics. The new source is free of density jumps and instabilities and shows a very good stability for plasma potential, and the dominant negative ion species is F{sup -}. The magnetic field in plasma volume is negligible and there is no contamination by filaments. The etching rate by negative ions measured in Ar/SF{sub 6}/O{sub 2} mixtures was almost similar with that by positive ions reaching 700 nm/min.

Stamate, E. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde 4000 (Denmark); Draghici, M. [Infineon Technologies Austria AG, Siemensstrasse 2, Villach 9500 (Austria)

2012-04-15T23:59:59.000Z

364

High-energy electron observations by PPB-BETS flight in Antarctica  

E-Print Network (OSTI)

We have observed cosmic-ray electrons from 10 GeV to 800 GeV by a long duration balloon flight using Polar Patrol Balloon (PPB) in Antarctica. The observation was carried out for 13 days at an average altitude of 35 km in January 2004. The detector is an imaging calorimeter composed of scintillating-fiber belts and plastic scintillators inserted between lead plates with 9 radiation lengths. The performance of the detector has been confirmed by the CERN-SPS beam test and also investigated by Monte-Carlo simulations. New telemetry system using a commercial satellite of Iridium, power supply by solar batteries, and automatic level control using CPU have successfully been developed and operated during the flight. From the long duration balloon observations, we derived the energy spectrum of cosmic-ray electrons in the energy range from 100 GeV to 800 GeV. In addition, for the first time we derived the electron arrival directions above 100 GeV, which is consistent with the isotropic distribution.

S. Torii; T. Yamagami; T. Tamura; K. Yoshida; H. Kitamura; K. Anraku; J. Chang; M. Ejiri; I. Iijima; A. Kadokura; K. Kasahara; Y. Katayose; T. Kobayashi; Y. Komori; Y. Matsuzaka; K. Mizutani; H. Murakami; M. Namiki; J. Nishimura; S. Ohta; Y. Saito; M. Shibata; N. Tateyama; H. Yamagishi; T. Yamashita; T. Yuda

2008-09-04T23:59:59.000Z

365

High fidelity gate operations within the coupled nuclear and electron spins of a nitrogen vacancy center in diamond  

E-Print Network (OSTI)

In this article we investigate the dynamics of a single negatively charged nitrogen-vacancy center (NV-) coupled to the spin of the nucleus of a 15-nitrogen atom and show that high fidelity gate operations are possible without the need for complicated composite pulse sequences. These operations include both the electron and nuclear spin rotations, as well as an entangling gate between them. These are experimentally realizable gates with current technology of sufficiently high fidelities that they can be used to build graph states for quantum information processing tasks.

Mark S. Everitt; Simon Devitt; W. J. Munro; Kae Nemoto

2013-09-12T23:59:59.000Z

366

Analysis and experimental results of a single-stage high-power-factor electronic ballast based on flyback converter  

SciTech Connect

A new single-stage high-power-factor electronic ballast based on a flyback converter is presented in this paper. The ballast is able to supply a fluorescent lamp assuring a high-input power factor for the utility line. Other features are lamp power regulation against line voltage variations and low lamp current crest factor, both assuring long lamp life. The ballast is analyzed at steady-state operation, and design equations and characteristics are obtained. Also, a procedure for the ballast design is presented. Finally, simulation and experimental results from a laboratory prototype are shown.

Calleja, A.J.; Alonso, J.M.; Lopez, E.; Ribas, J.; Martinez, J.A.; Rico-Secades, M.

1999-11-01T23:59:59.000Z

367

Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas  

SciTech Connect

We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

2011-09-15T23:59:59.000Z

368

High power microwave generator  

DOE Patents (OSTI)

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

Ekdahl, C.A.

1983-12-29T23:59:59.000Z

369

High power microwave generator  

DOE Patents (OSTI)

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

Ekdahl, Carl A. (Albuquerque, NM)

1986-01-01T23:59:59.000Z

370

Electron Beam Ion Trap (EBIT) Facility  

Science Conference Proceedings (OSTI)

... At these temperatures, even the heaviest atoms shed most of their electrons. ... The ions are probed with an intense electron beam, and the emitted ...

2013-06-06T23:59:59.000Z

371

Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics  

SciTech Connect

GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grid—eliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grid’s network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

None

2012-01-23T23:59:59.000Z

372

Intensity Frontier Instrumentation  

E-Print Network (OSTI)

This report summarizes findings of the 2013 Snowmass Community Summer Study Instrumentation Frontier's subgroup on the Intensity Frontier. This report is directed at identifying instrumentation R&D needed to support particle physics research over the coming decades at the Intensity Frontier.

S. H. Kettell; R. A. Rameika; R. S. Tschirhart

2013-09-26T23:59:59.000Z

373

Light intensity compressor  

DOE Patents (OSTI)

In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

Rushford, Michael C. (Livermore, CA)

1990-01-01T23:59:59.000Z

374

INTENSITY OF BETATRON RADIATION AS FUNCTION OF INJECTION VOLTAGE  

SciTech Connect

The intensity of betatron radiation emission as a function of injection voltage was studied using a 25-Mev betatron with a 350-kw external electron injector. The injection voltage was measured every 20 to 30 kw from 50 to 250 kw. The results showed that up to 250 kw, emission intensity increases according to theory. It is suggested that an increase in injection intensity up to 1000 kw and over should result in a considerable rise in emission intensity. (R.V.J.)

Moskalev, V.A.; Okulov, B.V.

1962-09-01T23:59:59.000Z

375

Impact of proton irradiation on dc performance of AlGaN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

The effects of proton irradiation dose on dc characteristics and the reliability of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. The HEMTs were irradiated with protons at a fixed energy of 5 MeV and doses ranging from 109 to 2 1014 cm-2. For the dc characteristics, there was only minimal degradation of saturation drain current (IDSS), transconductance (gm), electron mobility and sheet carrier concentration at doses below 2 1013 cm-2, while the reduction of these parameters were 15%, 9%, 41% and 16.6%, respectively, at a dose of 2 1014 cm-2. At this same dose condition, increases of 37% in drain breakdown voltage (VBR) and of 45% in critical voltage (Vcri) were observed. The improvement of device reliability was attributed to the modification of the depletion region due to the introduction of a higher density of defects after irradiation at a higher dose.

Liu, L. [University of Florida, Gainesville; Cuervo, C.V. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Kravchenko, Ivan I [ORNL

2013-01-01T23:59:59.000Z

376

Electronic Structure of LaOFeP - a Different Type of High Temperature...  

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

discovery not only ended the monopoly of copper oxides in the family of high temperature superconductors, but also provides a new direction to understand the essential...

377

Existence domains of arbitrary amplitude nonlinear structures in two-electron temperature space plasmas. II. High-frequency electron-acoustic solitons  

Science Conference Proceedings (OSTI)

A three-component plasma model composed of ions, cool electrons, and hot electrons is adopted to investigate the existence of large amplitude electron-acoustic solitons not only for the model for which inertia and pressure are retained for all plasma species which are assumed to be adiabatic but also neglecting inertial effects of the hot electrons. Using the Sagdeev potential formalism, the Mach number ranges supporting the existence of large amplitude electron-acoustic solitons are presented. The limitations on the attainable amplitudes of electron-acoustic solitons having negative potentials are attributed to a number of different physical reasons, such as the number density of either the cool electrons or hot electrons ceases to be real valued beyond the upper Mach number limit, or, alternatively, a negative potential double layer occurs. Electron-acoustic solitons having positive potentials are found to be supported only if inertial effects of the hot electrons are retained and these are found to be limited only by positive potential double layers.

Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Modderdam Road, Bellville 7530 (South Africa); Singh, S. V. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

2012-12-15T23:59:59.000Z

378

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail. (AIP) {copyright} {ital 1999 American Institute of Physics.}

Rosenzweig, J.B. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Le Sage, G.P. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-01T23:59:59.000Z

379

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail.

Rosenzweig, J. B.; Le Sage, G. P. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-12T23:59:59.000Z

380

The Intense Radiation Gas  

E-Print Network (OSTI)

We present a new dispersion relation for photons that are nonlinearly interacting with a radiation gas of arbitrary intensity due to photon-photon scattering. It is found that the photon phase velocity decreases with increasing radiation intensity, it and attains a minimum value in the limit of super-intense fields. By using Hamilton's ray equations, a self-consistent kinetic theory for interacting photons is formulated. The interaction between an electromagnetic pulse and the radiation gas is shown to produce pulse self-compression and nonlinear saturation. Implications of our new results are discussed.

M. Marklund; P. K. Shukla; B. Eliasson

2004-10-14T23:59:59.000Z

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


381

High frequency transformerless electronics ballast using double inductor-capacitor resonant power conversion for gas discharge lamps  

SciTech Connect

A novel high frequency LCLC double resonant electronic ballast has been developed for gas discharge lamp applications. The ballast consists of a half-bridge inverter which switches at zero voltage crossing and an LCLC resonant circuit which converts a low ac voltage to a high ac voltage. The LCLC resonant circuit has two LC stages. The first LC stage produces a high voltage before the lamp is ignited. The second LC stage limits lamp current with the circuit inductance after the lamp is ignited. In another embodiment a filament power supply is provided for soft start up and for dimming the lamp. The filament power supply is a secondary of the second resonant inductor. 27 figs.

Lai, J.S.

1995-06-20T23:59:59.000Z

382

Analysis and design of a high power factor, single-stage electronic dimming ballast  

SciTech Connect

This paper presents the analysis, design, and practical consideration of a single-stage electronic dimming ballast with unity power factor. The power stage of the ballast is derived from combining a buck-boost converter and a half-bridge series-resonant parallel-loaded inverter (SRPLI). With the plasma model of the lamp, the analysis of the ballast is carried out, from which the key equations used for dimming control are derived. Starting performance and dimming consideration are also addressed in the paper. In this dimming ballast, both pulsewidth modulation (PWM) and variable-frequency control strategies are employed. The discussed ballast with the controls can save a controller and a switch driver, reduce size and cost, and possibly increase system reliability over conventional two-stage systems in the applications with moderate power level. Simulated and experimental results of the ballast for an OSRAM T8 32-W lamp are used to verify the discussion.

Wu, T.F.; Yu, T.H. [National Chung Cheng Univ., Chia-Yi (Taiwan, Province of China)

1998-05-01T23:59:59.000Z

383

Anisotropic electron coupling as a phenomenological model for high-[ital T][sub [ital c  

Science Conference Proceedings (OSTI)

A three-dimensional weak coupling BCS model with an [ital anisotropic] pairing interaction in momentum space is reported. It exhibits an anisotropic gap in accord with recent experimental observations for high-[ital T][sub [ital c

Langfeld, K. (Institut fuer Theoretische Physik, Universitaet Tuebingen, DW-7400 Tuebingen (Germany) Physik Department, Technische Universitaet Muenchen, DW-8046 Garching (Germany)); Frey, E. (Lyman Laboratory of Physics, Harvard University, Cambridge, Massachusetts ( ))

1993-08-01T23:59:59.000Z

384

Investigation of electron temperature gradient driven micro-reconnecting modes in toroidal high-energy plasmas  

E-Print Network (OSTI)

Experiments carried out with magnetically confined, high temperature plasmas have revealed important effects that have yet to be justified by existing theory. In particular, there arises an anomalous particle inflow in the ...

Takasaki, Kevin T. (Keven Takao)

2007-01-01T23:59:59.000Z

385

High average power CW FELs (Free Electron Laser) for application to plasma heating: Designs and experiments  

SciTech Connect

A short period wiggler (period {approximately} 1 cm), sheet beam FEL has been proposed as a low-cost source of high average power (1 MW) millimeter-wave radiation for plasma heating and space-based radar applications. Recent calculation and experiments have confirmed the feasibility of this concept in such critical areas as rf wall heating, intercepted beam ( body'') current, and high voltage (0.5 - 1 MV) sheet beam generation and propagation. Results of preliminary low-gain sheet beam FEL oscillator experiments using a field emission diode and pulse line accelerator have verified that lasing occurs at the predicted FEL frequency. Measured start oscillation currents also appear consistent with theoretical estimates. Finally, we consider the possibilities of using a short-period, superconducting planar wiggler for improved beam confinement, as well as access to the high gain, strong pump Compton regime with its potential for highly efficient FEL operation.

Booske, J.H.; Granatstein, V.L.; Radack, D.J.; Antonsen, T.M. Jr.; Bidwell, S.; Carmel, Y.; Destler, W.W.; Latham, P.E.; Levush, B.; Mayergoyz, I.D.; Zhang, Z.X. (Maryland Univ., College Park, MD (USA). Lab. for Plasma Research); Freund, H.P. (Science Applications International Corp., McLean, VA (USA))

1989-01-01T23:59:59.000Z

386

Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry  

E-Print Network (OSTI)

Four hydroxynitrates (R(OH)R'ONO2) representative of atmospheric volatile organic compound (VOC) oxidation products were synthesized, nebulized and sampled into an Aerodyne High Resolution Time of Flight Aerosol Mass ...

Rollins, A. W.

387

Design of a miniature high-speed carbon-nanotube-enhanced ultracapacitor for electronics applications  

E-Print Network (OSTI)

Electrolytic capacitors, the current standard for high-value capacitors, are one of the most challenging components to miniaturize, accounting for up to 1/3 of the volume in some power devices, and are the weak link with ...

D'Asaro, Matthew E. (Matthew Eric)

2012-01-01T23:59:59.000Z

388

Effects of proton irradiation on dc characteristics of InAlN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

The effects of proton irradiation on the dc characteristics of InAlN/GaN high electron mobility transistors were investigated. In this study we used 5 MeV protons with doses varying from 21011 to 21015 cm2. The transfer resistance and contact resistivity suffered more degradation as compared to the sheet resistance. With irradiation at the highest dose of 21015 cm2, both forward- and reverse-bias gate currents were increased after proton irradiation. A negative threshold-shift and reduction of the saturation drain current were also observed as a result of radiation-induced carrier scattering and carrier removal. Devices irradiated with doses of 21011 to 21015 cm2 exhibited minimal degradation of the saturation drain current and extrinsic trans- conductance. These results show that InAlN/GaN high electron mobility transistors are attractive for space-based applications when high-energy proton fluxes are present. VC 2011 American Vacuum Society. [DOI: 10.1116/1.3644480

Lo, C. F. [University of Florida; Liu, L. [University of Florida, Gainesville; Ren, F. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

2011-01-01T23:59:59.000Z

389

The Hurricane Intensity Issue  

Science Conference Proceedings (OSTI)

The intensity issue of hurricanes is addressed in this paper using the angular momentum budget of a hurricane in storm-relative cylindrical coordinates and a scale-interaction approach. In the angular momentum budget in storm-relative coordinates,...

T. N. Krishnamurti; S. Pattnaik; L. Stefanova; T. S. V. Vijaya Kumar; B. P. Mackey; A. J. O’Shay; Richard J. Pasch

2005-07-01T23:59:59.000Z

390

Theory of coupled whistler-electron temperature gradient mode in high beta plasma: Application to linear plasma device  

Science Conference Proceedings (OSTI)

This paper presents a theory of coupled whistler (W) and electron temperature gradient (ETG) mode using two-fluid model in high beta plasma. Non-adiabatic ion response, parallel magnetic field perturbation ({delta}B{sub z}), perpendicular magnetic flutter ({delta}B{sub perpendicular}), and electron collisions are included in the treatment of theory. A linear dispersion relation for whistler-electron temperature gradient (W-ETG) mode is derived. The numerical results obtained from this relation are compared with the experimental results observed in large volume plasma device (LVPD) [Awasthi et al., Phys. Plasma 17, 42109 (2010)]. The theory predicts that the instability grows only where the temperature gradient is finite and the density gradient flat. For the parameters of the experiment, theoretically estimated frequency and wave number of W-ETG mode match with the values corresponding to the peak in the power spectrum observed in LVPD. By using simple mixing length argument, estimated level of fluctuations of W-ETG mode is in the range of fluctuation level observed in LVPD.

Singh, S. K.; Awasthi, L. M.; Singh, R.; Kaw, P. K.; Jha, R.; Mattoo, S. K. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

2011-10-15T23:59:59.000Z

391

High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam  

DOE Patents (OSTI)

The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

Brown, Jr., R. Malcolm (Austin, TX); Barnes, Zack (Austin, TX); Sawatari, Chie (Shizuoka, JP); Kondo, Tetsuo (Kukuoka, JP)

2008-02-26T23:59:59.000Z

392

Characterization methodology for pseudomorphic high electron mobility transistors using surface photovoltage spectroscopy  

E-Print Network (OSTI)

for the characterization of PHEMT structures. Information about the energy band diagram and related fields and charges and their analysis are shown to provide values for the electrical parameters of the structure. The sensitivity market of monolithic microwave integrated circuits. PHEMTs combine the high conductivity of an In

Shapira, Yoram

393

Self?aligned high electron mobility transistor gate fabrication using focused ion beams  

Science Conference Proceedings (OSTI)

A new gate fabrication technique has been developed based on focused ion beam exposure and reactive ion etching of a polymethylmethacrylate (PMMA)/Ge/PMMA multilevel resist structure. The focused ion beam exposes the thin PMMA imaging layer that is transferred directly to the germanium layer using reactive ion etching (RIE). The underlying resist is etched first in oxygen at high pressure

G. M. Atkinson; R. L. Kubena; L. E. Larson; L. D. Nguyen; F. P. Stratton; L. M. Jelloian; M. V. Le; H. McNulty

1991-01-01T23:59:59.000Z

394

Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals  

SciTech Connect

We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

Stoupin, Stanislav; Shvyd'ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey [Advanced Photon Source, Argonne National Laboratory, Illinois 60439 (United States)

2012-02-15T23:59:59.000Z

395

Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.  

Science Conference Proceedings (OSTI)

We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

Stoupin, S.; Shvydko, Y.; Shu, D.; Khachatryan, R.; Xiao, X. (X-Ray Science Division)

2012-01-01T23:59:59.000Z

396

Observation of Synchrotron Radiation from Electrons Accelerated in a Petawatt-Laser-Generated Plasma Cavity  

Science Conference Proceedings (OSTI)

The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured synchrotron spectrum is found to scale as the Maxwellian temperature of the simultaneously measured electron spectra. At low laser intensity transverse oscillations are negligible as the electrons are predominantly accelerated axially by the laser generated wakefield. At high laser intensity, electrons are directly accelerated by the laser and enter a highly radiative regime with up to 5% of their energy converted into x rays.

Kneip, S.; Nagel, S. R.; Bellei, C.; Dangor, A. E.; Mangles, S. P. D.; Nilson, P. M.; Willingale, L.; Najmudin, Z. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Bourgeois, N.; Marques, J. R. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau (France); Gopal, A. [Department of Electronics, Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Heathcote, R. [Central Laser Facility, Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom); Maksimchuk, A.; Reed, S. [Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States); Phuoc, K. Ta; Rousse, A. [Laboratoire d'Optique Applique, ENSTA, Ecole Polytechnique, 91761 Palaiseau (France); Tzoufras, M.; Tsung, F. S.; Mori, W. B. [Department of Physics and Astronomy and Department of Electrical Engineering, UCLA, Los Angeles, California 90095 (United States); Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States)

2008-03-14T23:59:59.000Z

397

Radiation-induced surface degradation of GaAs and high electron mobility transistor structures  

Science Conference Proceedings (OSTI)

Transistor heterostructures with high-carrier-mobility have been studied. It is shown that, as the {gamma}-irradiation dose {Phi} increases, their degradation occurs in the following sequence. (i) At {Phi} 0.2-eV decrease in the diffusion energy of intrinsic defects and, probably, atmospheric oxygen. (ii) At {Phi} > 10{sup 7} rad, highly structurally disordered regions larger than 1 {mu}m are formed near microscopic defects or dislocations. (iii) At {Phi} > 10{sup 8} rad, there occurs degradation of the internal AlGaAs/InGaAs/GaAs interfaces and the working channel. An effective method for studying the degradation processes in heterostructures is to employ a set of structural diagnostic methods to analyze processes of radiation-induced and aging degradation, in combination with theoretical simulation of the occurring processes.

Bobyl, A. V.; Konnikov, S. G.; Ustinov, V. M.; Baidakova, M. V.; Maleev, N. A.; Sakseev, D. A. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Konakova, R. V., E-mail: konakova@isp.kiev.ua; Milenin, V. V.; Prokopenko, I. V. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine)

2012-06-15T23:59:59.000Z

398

Building dependability arguments for software intensive systems  

E-Print Network (OSTI)

A method is introduced for structuring and guiding the development of end-to-end dependability arguments. The goal is to establish high-level requirements of complex software-intensive systems, especially properties that ...

Seater, Robert Morrison

2009-01-01T23:59:59.000Z

399

Le Bail Intensity Extraction  

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

Le Bail Intensity Extraction Le Bail Intensity Extraction Presentation Goal Introduce the concepts behind LeBail fitting; why it is useful and how to perform a Le Bail fit with GSAS. Format: PDF slides or a RealPlayer video of the slides with accompanying audio and a demo video that shows how a Le Bail fit is performed. Presentation Outline What is the Le Bail method? Other approaches Why use the Le Bail method? Parameter fitting with Le Bail intensity extraction Le Bail refinement strategies Avoiding problems with background fitting: BKGEDIT Demo: an example Le Bail fit Links Le Bail lecture Slides (as PDF file) FlashMovie presentation with index (best viewed with 1024x768 or better screen resolution) FlashMovie file (800x600 pixels) Le Bail demo FlashMovie presentation with index (best viewed with 1024x768 or

400

Coherent terahertz radiation from high-harmonic component of modulated free-electron beam in a tapered two-asymmetric grating structure  

SciTech Connect

Based on the mechanism of incoherent diffraction radiation excited by an electron bunch in a waveguide with periodic structure, this paper presents the concept of coherent terahertz (THz) radiation from the high-harmonic component of a modulated free-electron beam in a tapered two-asymmetric grating structure. The results show that in this mechanism 0.43 THz radiation can be generated with 10 A/cm{sup 2} current density, and the efficiency can reach 0.5%. Because of the low required current density and relative high efficiency, this concept shows the application potential for electron-beam-driven terahertz sources.

Zhang Yaxin; Zhou Yucong; Dong Liang; Liu Shenggang [Terahertz Science and Technology Research Center, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2012-09-17T23:59:59.000Z

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


401

X-ray scattering intensities of water at extreme pressure and temperature  

DOE Green Energy (OSTI)

We have calculated the coherent x-ray scattering intensity of several phases of water at 1500 and 2000 K under high pressure, using ab initio Density Functional Theory (DFT). Our calculations span the molecular liquid, ice VII, and superionic solid phases, including the recently predicted symmetrically hydrogen bonded region of the superionic phase. We show that wide angle x-ray scattering intensity could be used to determine phase boundaries between these high pressure phases, and we compare the results for ice VII and superionic water. We compute simulated spectra and provide new atomic scattering form factors for water at extreme conditions, which take into account frequently neglected changes in ionic charge and electron delocalization. We show that our modifed atomic form factors allow for a nearly exact comaprison to the total x-ray scattering intensities calculated from DFT. Finally, we analyze the effect our new form factors have on determination of the oxygen-oxygen radial distribution function.

Goldman, N; Fried, L E

2007-01-03T23:59:59.000Z

402

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

SciTech Connect

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

Hopkins, Patrick E.

2011-10-01T23:59:59.000Z

403

Design and Fabrication of the RHIC Electron-Cooling Experiment High Beta Cavity and Cryomodule  

Science Conference Proceedings (OSTI)

The summary of this report is: (1) A high-current SRF cavity for an Energy Recovery Linac (ERL) has been designed by BNL and AES and fabricated by AES; (2) The cavity was cleaned and tested by JLAB with BNL personnel support; (3) Cavity performance exceeded goal of 20 MV/m at Q{sub 0} > 1 x 10{sup 10} and far exceeded requirement of 15 MV/m at Q{sub 0} > 1 x 10{sup 10}; (4) Hermetic String assembled at JLAB with BNL personnel support and shipped to BNL; and (5) BNL has recently completed Cryomodule assembly and unit is ready for installation in the ERL vault.

Holmes,D.; Calderaro, M.; Cole, M.; Falletta, M.; Peterson, E.; Rathke, J.; Schultheiss, T.; Wong, R.; Ben-Zvi, I.; Burrill, A.; Calaga, R.; McIntyre, G.

2008-11-17T23:59:59.000Z

404

Energy Intensity Strategy  

E-Print Network (OSTI)

Our presentation will cover how we began the journey of conserving energy at our facility. We’ll discuss a basic layout of our energy intensity plan and the impact our team has had on the process, what tools we’re using, what goals have been identified, how we structured the plan to include our team in the process and so on.

Rappolee, D.

2008-01-01T23:59:59.000Z

405

High-speed, multi-channel detector readout electronics for fast radiation detectors  

SciTech Connect

In this project, we are developing a high speed digital spectrometer that a) captures detector waveforms at rates up to 500 MSPS b) has upgraded event data acquisition with additional data buffers for zero dead time operation c) moves energy calculations to the FPGA to increase spectrometer throughput in fast scintillator applications d) uses a streamlined architecture and high speed data interface for even faster readout to the host PC These features are in addition to the standard functions in our existing spectrometers such as digitization, programmable trigger and energy filters, pileup inspection, data acquisition with energy and time stamps, MCA histograms, and run statistics. In Phase I, we upgraded one of our existing spectrometer designs to demonstrate the key principle of fast waveform capture using a 500 MSPS, 12 bit ADC and a Xilinx Virtex-4 FPGA. This upgraded spectrometer, named P500, performed well in initial tests of energy resolution, pulse shape analysis, and timing measurements, thus achieving item (a) above. In Phase II, we are revising the P500 to build a commercial prototype with the improvements listed in items (b)-(d). As described in the previous report, two devices were built to pursue this goal, named the Pixie-500 and the Pixie-500 Express. The Pixie-500 has only minor improvements from the Phase I prototype and is intended as an early commercial product (its production and part of its development were funded outside the SBIR). It also allows testing of the ADC performance in real applications.The Pixie-500 Express (or Pixie-500e) includes all of the improvements (b)-(d). At the end of Phase II of the project, we have tested and debugged the hardware, firmware and software of the Pixie-500 Express prototype boards delivered 12/3/2010. This proved substantially more complex than anticipated. At the time of writing, all hardware bugs have been fixed, the PCI Express interface is working, the SDRAM has been successfully tested and the SHARC DSP has been booted with preliminary code. All new ICs and circuitry on the prototype are working properly, however some of the planned firmware and software functions have not yet been completely implemented and debugged. Overall, due to the unanticipated complexity of the PCI Express interface, some aspects of the project could not be completed with the time and funds available in Phase II. These aspects will be completed in self-funded Phase III.

Hennig, Wolfgang

2012-06-22T23:59:59.000Z

406

Effect of a high-energy proton-irradiation dose on the electron mobility in n-Si crystals  

Science Conference Proceedings (OSTI)

n-Si single crystals produced by the floating zone method are studied. The concentration of electrons in the crystals is 6 Multiplication-Sign 10{sup 13} cm{sup -3}. The samples are irradiated with 25-MeV protons at 300 K. The irradiation dose is varied in the range (1.8-8.1) Multiplication-Sign 10{sup 12} cm{sup -2}. The measurements are carried out by means of the Hall technique in the range of temperatures T = 77-300 K. In samples irradiated with different proton doses, a sharp increase in the experimental effective Hall mobility {mu}{sub eff} or a deep minimum in the dependence {mu}{sub eff}(T) in the region of phonon scattering of electrons is observed immediately after irradiation or after aging of the samples, respectively. The observed effect is attributed to the formation of high-conductivity (metal-like) inclusions in the irradiated samples and to changes in the degree of screening of the inclusions by impurity-defect shells in relation to the irradiation dose, the time of natural aging, and the temperature of measurements. The impurity-defect shells are formed around metal-like inclusions during isochronal annealing or natural aging of the irradiated samples. It is suggested that metal-like inclusions formed in the n-Si crystals on irradiation with protons with the energy 25 MeV are atomic nanoclusters with an 80-nm radius.

Pagava, T. A., E-mail: tpagava@gtu.ge; Maisuradze, N. I.; Beridze, M. G. [Georgian Technical University, Department of Physics (Georgia)

2011-05-15T23:59:59.000Z

407

SnO2-gated AlGaN/GaN high electron mobility transistors based oxygen sensors  

Science Conference Proceedings (OSTI)

Hydrothermally grown SnO2 was integrated with AlGaN/GaN high electron mobility transistor (HEMT) sensor as the gate electrode for oxygen detection. The crystalline of the SnO2 was improved after annealing at 400 C. The grain growth kinetics of the SnO2 nanomaterials, together with the O2 gas sensing properties and sensing mechanism of the SnO2 gated HEMT sensors were investigated. Detection of 1% oxygen in nitrogen at 100 C was possible. A low operation temperature and low power consumption oxygen sensor can be achieved by combining the SnO2 films with the AlGaN/GaN HEMT structure

Hung, S.T. [Feng Chia University, Taichung, Taiwan; Chung, Chi-Jung [Feng Chia University, Taichung, Taiwan; Chen, Chin Ching [University of Florida, Gainesville; Lo, C. F. [University of Florida; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Kravchenko, Ivan I [ORNL

2012-01-01T23:59:59.000Z

408

The effects of proton irradiation on the reliability of InAlN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

We have investigated the effect of proton irradiation on reliability of InAlN/GaN high electron mobility transistors (HEMTs). Devices were subjected to 5-15 MeV proton irradiations with a fixed dose of 5 1015 cm-2, or to a different doses of 2 1011, 5 1013 or 2 1015 cm-2 of protons at a fixed energy of 5 MeV. During off-state electrical stressing, the typical critical voltage for un-irradiated devices was 45 to 55 V. By sharp contrast, no critical voltage was detected for proton irradiated HEMTs up to 100 V, which was instrument-limited. After electrical stressing, no degradation was observed for the drain or gate current-voltage characteristics of the proton-irradiated HEMTs. However, the drain current decreased ~12%, and the reverse bias gate leakage current increased more than two orders of magnitude for un-irradiated HEMTs as a result of electrical stressing.

Liu, L. [University of Florida, Gainesville; Lo, C. F. [University of Florida; Xi, Y. Y. [University of Florida, Gainesville; Wang, Y.l. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL; Ren, F. [University of Florida

2012-01-01T23:59:59.000Z

409

Effect of high-energy electron irradiation in an electron microscope column on fluorides of alkaline earth elements (CaF{sub 2}, SrF{sub 2}, and BaF{sub 2})  

SciTech Connect

The effect of high-energy (150 eV) electron irradiation in an electron microscope column on crystals of fluorides of alkaline earth elements CaF{sub 2}, SrF{sub 2}, and BaF{sub 2} is studied. During structural investigations by electron diffraction and electron microscopy, the electron irradiation causes chemical changes in MF{sub 2} crystals such as the desorption of fluorine and the accumulation of oxygen in the irradiated area with the formation of oxide MO. The fluorine desorption rate increases significantly when the electron-beam density exceeds the threshold value of {approx}2 Multiplication-Sign 10{sup 3} pA/cm{sup 2}). In BaF{sub 2} samples, the transformation of BaO into Ba(OH){sub 2} was observed when irradiation stopped. The renewal of irradiation is accompanied by the inverse transformation of Ba(OH){sub 2} into BaO. In the initial stage of irradiation of all MF{sub 2} compounds, the oxide phase is in the single-crystal state with a lattice highly matched with the MF{sub 2} matrix. When the irradiation dose is increased, the oxide phase passes to the polycrystalline phase. Gaseous products of MF{sub 2} destruction (in the form of bubbles several nanometers in diameter) form a rectangular array with a period of {approx}20 nm in the sample.

Nikolaichik, V. I. [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation); Sobolev, B. P., E-mail: sobolev@ns.crys.ras.ru; Zaporozhets, M. A.; Avilov, A. S. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2012-03-15T23:59:59.000Z

410

Numerical simulation of high-energy-electron gerated field in dielectrics of various geometries. Final report, June 1, 1979-May 15, 1980  

SciTech Connect

It has been observed that the exposure of dielectrics to electron beams can produce an electric field of sufficient magnitude to cause dielectric breakdown. The present investigations will be directed to calculate the electric field intensity in dielectrics under spherical and cylindrical geometries. In the spherical geometry the method of multiple images renders the full numerical calculation unnecessary, whereas in a finite length cylindrical geometry the full numerical calculation seems to be inevitable. A description and results of the spherical geometry are presented and a more detailed presentation of the finite cylinder geometry is given.

Yee, K.S.

1980-01-01T23:59:59.000Z

411

High-Pressure Evolution of Fe2O3 Electronic Structure Revealed by X-ray Absorption  

SciTech Connect

We report the first high pressure measurement of the Fe K-edge in hematite (Fe{sub 2}O{sub 3}) by X-ray absorption spectroscopy in partial fluorescence yield geometry. The pressure-induced evolution of the electronic structure as Fe{sub 2}O{sub 3} transforms from a high-spin insulator to a low-spin metal is reflected in the x-ray absorption pre-edge. The crystal field splitting energy was found to increase monotonically with pressure up to 48 GPa, above which a series of phase transitions occur. Atomic multiplet, cluster diagonalization, and density-functional calculations were performed to simulate the pre-edge absorption spectra, showing good qualitative agreement with the measurements. The mechanism for the pressure-induced phase transitions of Fe{sub 2}O{sub 3} is discussed and it is shown that ligand hybridization significantly reduces the critical high-spin/low-spin gap pressure.

Kao, Chi-Chang

2011-08-12T23:59:59.000Z

412

Unlocking energy intensive habits  

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

energy intensive habits energy intensive habits Presentation at LBL Oct 10, 2013 by Hal Wilhite Professor and Research Director University of Oslo Centre for Development and the Environment Source: WWF US EIA Outlook 2011 Conventional framing of the energy consumption and savings * Sovereign consumers * Economically rational and persistentely reflexive. * Uninfluenced by social and material conditions of everyday life * Focus on efficiency and not on size and volume which is for the most part treated as an indifferent variable Cognitive reductionism The change of frame * From individual to socio-material * From rational/reflexive experience-based (practical) knowledge * From efficiency to reduction A theory of habit * Acknowledges the role of lived experience (history, both cultural and personal) in forming

413

New Electronic Light Sources for Sustainability in a Greener Environment  

Science Conference Proceedings (OSTI)

This EPRI Technical Update continues the technical assessment of advanced lighting technologies in the product areaselectronic linear fluorescent, electronic compact fluorescent, electronic high-intensity discharge (HID), and light-emitting diode (LED). This year, a new type of light sourcesolid-state plasma lighting (a miniature HID technology)was assessed. This project demonstrates how light sources are making their way into new designs providing new types of light fixtures. A total of seven products w...

2010-12-31T23:59:59.000Z

414

NEUTRON FLUX INTENSITY DETECTION  

DOE Patents (OSTI)

A method of measuring the instantaneous intensity of neutron flux in the core of a nuclear reactor is described. A target gas capable of being transmuted by neutron bombardment to a product having a resonance absorption line nt a particular microwave frequency is passed through the core of the reactor. Frequency-modulated microwave energy is passed through the target gas and the attenuation of the energy due to the formation of the transmuted product is measured. (AEC)

Russell, J.T.

1964-04-21T23:59:59.000Z

415

Suppression of Exponential Electronic Decay in a Charged Environment  

Science Conference Proceedings (OSTI)

Inner-shell ionization of atoms and molecules leads to the creation of highly excited ionic states that often decay by electron emission. The dynamics of the decay is usually assumed to be exponential and the process is characterized by a decay rate. Here we show that in a multiply ionized cluster created by interaction with a high-intensity free-electron laser (FEL) radiation, trapping of the emitted electron by the neighboring ions changes the character of the decay dynamics qualitatively to the extent that it can become oscillatory instead of exponential. Implications of the predicted effect on Coster-Kronig and interatomic Coulombic decay processes induced by FELs are investigated.

Averbukh, Vitali [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, D-01187 Dresden (Germany); Saalmann, Ulf; Rost, Jan Michael [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, D-01187 Dresden (Germany); Max Planck Advanced Study Group at the Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg (Germany)

2010-06-11T23:59:59.000Z

416

New high- Tc benchmarks for organic superconductors based on ET (electron-donor) and C sub 60 (electron-acceptor) molecules  

SciTech Connect

The highest {Tc}'s achieved in organic electron-donor-based systems occur in two isostructural ET salts, viz., {kappa}-((ET){sub 2}Cu)(N(CN){sub 2})X, X = Br ({Tc} = 11.6 K, ambient pressure), X = Cl ({Tc} = 12.8 K, 0.3 kbar) whereas for the electron-acceptor-based systems derived from C{sub 60} they occur in K{sub 3}C{sub 60} ({Tc} = 19 K), Rb{sub 3}C{sub 60} ({Tc} = 29 K), Rb{sub x}Cs{sub y}C{sub 60} ({Tc} 33 K) and Rb{sub x}Tl{sub y}C{sub 60} ({Tc} {approx} 45 K). Research performed at Argonne National Laboratory, and based on the ET and C{sub 60} systems, is reviewed.

Williams, J.M.; Geiser, U.; Carlson, K.D.; Wang, H.H.; Kini, A.M.; Schultz, A.J.; Kwok, W.K.; Welp, U.; Crabtree, G.W. (Argonne National Lab., IL (United States)); Whangbo, M.H. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemistry); Schirber, J.E. (Sandia National Labs., Albuquerque, NM (United States))

1992-01-01T23:59:59.000Z

417

New high-{Tc} benchmarks for organic superconductors based on ET (electron-donor) and C{sub 60} (electron-acceptor) molecules  

SciTech Connect

The highest {Tc}`s achieved in organic electron-donor-based systems occur in two isostructural ET salts, viz., {kappa}-[(ET){sub 2}Cu][N(CN){sub 2}]X, X = Br ({Tc} = 11.6 K, ambient pressure), X = Cl ({Tc} = 12.8 K, 0.3 kbar) whereas for the electron-acceptor-based systems derived from C{sub 60} they occur in K{sub 3}C{sub 60} ({Tc} = 19 K), Rb{sub 3}C{sub 60} ({Tc} = 29 K), Rb{sub x}Cs{sub y}C{sub 60} ({Tc} 33 K) and Rb{sub x}Tl{sub y}C{sub 60} ({Tc} {approx} 45 K). Research performed at Argonne National Laboratory, and based on the ET and C{sub 60} systems, is reviewed.

Williams, J.M.; Geiser, U.; Carlson, K.D.; Wang, H.H.; Kini, A.M.; Schultz, A.J.; Kwok, W.K.; Welp, U.; Crabtree, G.W. [Argonne National Lab., IL (United States); Whangbo, M.H. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemistry; Schirber, J.E. [Sandia National Labs., Albuquerque, NM (United States)

1992-03-01T23:59:59.000Z

418

Aspects of a high intensity neutron source  

E-Print Network (OSTI)

A unique methodology for creating a neutron source model was developed for deuterons and protons incident on solid phase beryllium and lithium targets. This model was then validated against experimental results already ...

Chapman, Peter H. (Peter Henry)

2010-01-01T23:59:59.000Z

419

Energy Basics: High-Intensity Discharge Lighting  

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

and longest service life of any lighting type. It can save 75%-90% of lighting energy when it replaces incandescent lighting. HID lamps use an electric arc to produce...

420

Controlling double ionization of atoms in an intense bichromatic laser pulse  

SciTech Connect

We consider the classical dynamics of a two-electron system subjected to an intense bichromatic linearly polarized laser pulse. By varying the parameters of the field, such as the phase lag and the relative amplitude between the two colors of the field, we observe several trends from the statistical analysis of a large ensemble of trajectories initially in the ground-state energy of the helium atom: high sensitivity of the sequential double-ionization component, low sensitivity of the intensities where nonsequential double ionization occurs, while the corresponding yields can vary drastically. All these trends hold irrespective of which parameter is varied: the phase lag or the relative amplitude. We rationalize these observations by an analysis of the phase-space structures that drive the dynamics of this system and determine the extent of double ionization. These trends turn out to be mainly regulated by the dynamics of the inner electron.

Kamor, A.; Uzer, T. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Mauger, F.; Chandre, C. [Centre de Physique Theorique, CNRS, Aix-Marseille Universite, Campus de Luminy, case 907, 13288 Marseille cedex 09 (France)

2011-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity electron" from the National Library of EnergyBeta (NLEBeta).
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421

Higher order terms of radiative damping in extreme intense laser-matter interaction  

Science Conference Proceedings (OSTI)

The higher order terms of the Lorentz-Abraham-Dirac equation have been derived, and their effects are studied via a relativistic collisional particle-in-cell simulation. The dominant group of terms up to the fourth order of the Lorentz-Abraham-Dirac equation is identified for ultra-intense laser-matter interactions. The second order terms are found to be the damping terms of the Lorentz force while the first order terms represent friction in the equation of motion. Because the second order terms restrict electron acceleration during the laser interaction, electrons/ions are prevented from over-accelerating. Radiative damping becomes highly significant when I{>=} 10{sup 22} W/cm{sup 2} while Bremsstrahlung will be saturated, thus radiative damping will be a dominant source of hard x-rays in regimes at extreme intensities.

Pandit, Rishi R.; Sentoku, Yasuhiko [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

2012-07-15T23:59:59.000Z

422

Electron-beam-controlled gas lasers: discussion from the engineering viewpoint. Part II. Problems in the electrical design of very high energy systems  

SciTech Connect

Some problem areas in the design of very-high-energy electronbeam- controlled short-pulse gas lasers are discussed. One of the prime areas of interest is the high-voltage pulse generators for driving the electron gun and gas pumping. The use of pulse-forming networks for improving energy-transfer efficiency is discussed. The use of thermionic cathode devices will require a large ac power installation. The properties of alternate electron sources (cold cathode and plasma cathode devices) are reviewed. The impact of laser beam energy density limitations on system geometry and electrical design are discussed last. (auth)

Riepe, K.B.; Stapleton, R.E.

1973-01-01T23:59:59.000Z

423

Dependence on proton energy of degradation of AlGaN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

The effects of proton irradiation energy on dc, small signal, and large signal rf characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. AlGaN/GaN HEMTs were irradiated with protons at fixed fluence of 51015/cm2 and energies of 5, 10, and 15 MeV. Both dc and rf characteristics revealed more degradation at lower irradiation energy, with reductions of maximum transconductance of 11%, 22%, and 38%, and decreases in drain saturation current of 10%, 24%, and 46% for HEMTs exposed to 15, 10, and 5MeV protons, respectively. The increase in device degradation with decreasing proton energy is due to the increase in linear energy transfer and corresponding increase in nonionizing energy loss with decreasing proton energy in the active region of the HEMTs. After irradiation, both subthreshold drain leakage current and reverse gate current decreased more than 1 order of magnitude for all samples. The carrier removal rate was in the range 121 336 cm1 over the range of proton energies employed in this study

Liu, L. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Wang, Y.l. [University of Florida; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Fitch, Robert C [Air Force Research Laboratory, Wright-Patterson AFB, OH; Walker, Dennis E [Air Force Research Laboratory, Wright-Patterson AFB, OH; Chabak, Kelson D [Air Force Research Laboratory, Wright-Patterson AFB, OH; Gillespie, James k [Air Force Research Laboratory, Wright-Patterson AFB, OH; Tetlak, Stephen E [Air Force Research Laboratory, Wright-Patterson AFB, OH; Via, Glen D [Air Force Research Laboratory, Wright-Patterson AFB, OH; Crespo, Antonio [Air Force Research Laboratory, Wright-Patterson AFB, OH; Kravchenko, Ivan I [ORNL

2013-01-01T23:59:59.000Z

424

Proton irradiation energy dependence of dc and rf characteristics on InAlN/GaN high electron mobility transistors  

Science Conference Proceedings (OSTI)

The effects of proton irradiation energy on dc and rf characteristics of InAlN/GaN high electron mobility transistors (HEMTs) were investigated. A fixed proton dose of 51015 cm2 with 5, 10, and 15 MeV irradiation energies was used in this study. For the dc characteristics, degradation was observed for sheet resistance, transfer resistance, contact resistivity, saturation drain current, maximum transconductance, reverse-bias gate leakage current, and sub-threshold drain leakage current for all the irradiated HEMTs; however, the degree of the degradation was decreased as the irradiation energy increased. Similar trends were obtained for the rf performance of the devices, with 10% degradation of the unity gain cut-off frequency (fT) and maximum oscillation frequency ( fmax) for the HEMTs irradiated with 15 MeV protons but 30% for 5 MeV proton irradiation. The carrier removal rate was in the range 0.66 1.24 cm1 over the range of proton energies investigated

Lo, C. F. [University of Florida; Liu, L. [University of Florida, Gainesville; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Gila, Brent P. [University of Florida, Gainesville; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

2012-01-01T23:59:59.000Z

425

Evaluation of Miscellaneous and Electronic Device Energy Use...  

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

loads, energy utilisation intensity, healthcare facilities, hospital energy use, energy consumption. Abstract Miscellaneous and electronic loads (MELs) consume about...

426

Intense laser field ionization of atom and molecular ion.  

E-Print Network (OSTI)

??In order to understand how does the intense laser interact with matter we first of all study the ionization process. In this highly nonlinear region… (more)

Long, Zi Jian

2008-01-01T23:59:59.000Z

427

Figure 55. Residential delivered energy intensity in four ...  

U.S. Energy Information Administration (EIA)

Sheet3 Sheet2 Sheet1 Figure 55. Residential delivered energy intensity in four cases, 2005-2035 (index, 2005 = 1) Best Available Technology case High Technology case

428

Intensity Frontier Instrumentation  

SciTech Connect

The fundamental origin of flavor in the Standard Model (SM) remains a mystery. Despite the roughly eighty years since Rabi asked “Who ordered that?” upon learning of the discovery of the muon, we have not understood the reason that there are three generations or, more recently, why the quark and neutrino mixing matrices and masses are so different. The solution to the flavor problem would give profound insights into physics beyond the Standard Model (BSM) and tell us about the couplings and the mass scale at which the next level of insight can be found. The SM fails to explain all observed phenomena: new interactions and yet unseen particles must exist. They may manifest themselves by causing SM reactions to differ from often very precise predictions. The Intensity Frontier (1) explores these fundamental questions by searching for new physics in extremely rare processes or those forbidden in the SM. This often requires massive and/or extremely finely tuned detectors.

Kettell S.; Rameika, R.; Tshirhart, B.

2013-09-24T23:59:59.000Z

429

Generation of Femtosecond Electron And Photon Pulses  

SciTech Connect

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

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

2006-03-17T23:59:59.000Z

430

rf modulator design and phase amplitude control for a high-power free-electron-laser linac  

SciTech Connect

The continued interest for building tunable lasers using an electron accelerator as the source of primary energy has resulted in the design of a new accelerator. Earlier work by other members of the Los Alamos team has demonstrated that this design does work in an amplifier mode. The accelerator is to be upgraded for use in an oscillator experiment and the new rf power amplifier system must meet some of the very stringent demands for power and stability placed on the electron beam for the free-electron laser (FEL) interaction to be observed. These demands are particularly stringent because the electron beam energy ultimately will be circulated back through the accelerator so that the electron beam energy not used in the FEL interaction is not wasted. These considerations have to some measure been incorporated into the design of the second FEL system at Los Alamos and are discussed.

Hoeberling, R.F.; Tallerico, P.J.

1981-01-01T23:59:59.000Z

431

Electron Based Techniques  

Science Conference Proceedings (OSTI)

Mar 5, 2013 ... Characterization of Materials through High Resolution Coherent Imaging: Electron Based Techniques Sponsored by: TMS Structural Materials ...

432

Genomics of Electronic Materials  

Science Conference Proceedings (OSTI)

... Metamaterials; Highly correlated electron materials, eg superconductors, such as ... A near-field scanning microwave microscope for characterization ...

2013-08-08T23:59:59.000Z