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Sample records for center 19id undulator

  1. In situ X-ray data collection and structure phasing of protein crystals at Structural Biology Center 19-ID

    Energy Technology Data Exchange (ETDEWEB)

    Michalska, Karolina; Tan, Kemin; Chang, Changsoo; Li, Hui; Hatzos-Skintges, Catherine; Molitsky, Michael; Alkire, Randy; Joachimiak, Andrzej

    2015-10-15

    A prototype of a 96-well plate scanner forin situdata collection has been developed at the Structural Biology Center (SBC) beamline 19-ID, located at the Advanced Photon Source, USA. The applicability of this instrument for protein crystal diffraction screening and data collection at ambient temperature has been demonstrated. Several different protein crystals, including selenium-labeled, were used for data collection and successful SAD phasing. Without the common procedure of crystal handling and subsequent cryo-cooling for data collection atT= 100 K, crystals in a crystallization buffer show remarkably low mosaicity (<0.1°) until deterioration by radiation damage occurs. Data presented here show that cryo-cooling can cause some unexpected structural changes. Based on the results of this study, the integration of the plate scanner into the 19-ID end-station with automated controls is being prepared. With improvement of hardware and software,in situdata collection will become available for the SBC user program including remote access.

  2. Plasma undulator

    International Nuclear Information System (INIS)

    Two types of the undulator which is developed as a generator of the highly brilliant light for the synchrotron radiation sources and the free electron lasers, are newly proposed using the array of slender plasmas columns. One is the magnetic field type, in which the undulator force on the relativistic electron beam is generated with the electric current flowing through the plasma columns. The other is the electric field type, in which the undulator force is generated with the periodic variation of the density between the slender plasma columns. The production methods and stabilization ones of plasma columns are discussed. (author)

  3. Hybrid undulator numerical optimization

    Energy Technology Data Exchange (ETDEWEB)

    Hairetdinov, A.H. [Kurchatov Institute, Moscow (Russian Federation); Zukov, A.A. [Solid State Physics Institute, Chernogolovka (Russian Federation)

    1995-12-31

    3D properties of the hybrid undulator scheme arc studied numerically using PANDIRA code. It is shown that there exist two well defined sets of undulator parameters which provide either maximum on-axis field amplitude or minimal higher harmonics amplitude of the basic undulator field. Thus the alternative between higher field amplitude or pure sinusoidal field exists. The behavior of the undulator field amplitude and harmonics structure for a large set of (undulator gap)/(undulator wavelength) values is demonstrated.

  4. High harmonics focusing undulator

    Energy Technology Data Exchange (ETDEWEB)

    Varfolomeev, A.A.; Hairetdinov, A.H.; Smirnov, A.V.; Khlebnikov, A.S. [Kurchatov Institute, Moscow (Russian Federation)

    1995-12-31

    It was shown in our previous work that there exist a possibility to enhance significantly the {open_quote}natural{close_quote} focusing properties of the hybrid undulator. Here we analyze the actual undulator configurations which could provide such field structure. Numerical simulations using 2D code PANDIRA were carried out and the enhanced focusing properties of the undulator were demonstrated. The obtained results provide the solution for the beam transport in a very long (short wavelength) undulator schemes.

  5. Tuning The Laser Heater Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Zackary

    2010-12-03

    The laser heater undulator for the LCLS requires different tuning techniques than the main undulators. It is a pure permanent magnet (PPM) undulator, rather than the hybrid design of the main undulators. The PPM design allows analytic calculation of the undulator fields. The calculations let errors be introduced and correction techniques be derived. This note describes how the undulator was modelled, and the methods which were found to correct potential errors in the undulator. The laser heater undulator for the LCLS is a pure permanent magnet device requiring different tuning techniques than the main undulators. In this note, the laser heater undulator is modelled and tuning techniques to compensate various errors are derived.

  6. JSR undulator experiment

    International Nuclear Information System (INIS)

    JSR has an 1.5m long straight section for a insertion device. An undulator was installed in this straight section in July, 1991. The first observation of spontaneous radiation from this undulator was performed in August. The wavelength change due to K-parameter change was measured at the beam energy of 138.9MeV and 174.6MeV, and also measured was the tune shift due to the undulator insertion. These experimental results are in good agreements with calculations. (author)

  7. Interferometry using undulator sources

    International Nuclear Information System (INIS)

    Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in Soft X-Ray Projection Lithography, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), 18, 1089, and D. Attwood et al., Appl. Opt. 32, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg et al., in Extreme Ultra Lithography, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg et al., Proc. SPIE 2437, to be published, and K. Goldberg et al., J. Vac. Sci. Technol. B 13, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown. copyright 1996 American Institute of Physics

  8. The JLAB UV Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Gottschalk, Steven C. [STI, Washington, USA; Benson, Steven V. [JLAB; Moore, Steven Wesley [JLAB

    2013-05-01

    Recently the JLAB FEL has demonstrated 150 W at 400 nm and 200 W at 700 nm using a 33mm period undulator designed and built by STI Optronics. This paper describes the undulator design and performance. Two key requirements were low phase error, zero steering and offset end fields and small rms trajectory errors. We will describe a new genetic algorithm that allowed phase error minimization to 1.8 degrees while exceeding specifications. The mechanical design, control system and EPICS interface will also be summarized.

  9. Modelling of undulator sources

    International Nuclear Information System (INIS)

    We present a new code capable of realistically modelling the radiation from ideal undulator sources, including explicit electron emittance effects. The code has been developed as part of the SHADOW X-ray optics ray tracing program, in order to predict the performances of undulator-based optical systems. The approach is based on a simplified field distribution that allows an efficient calculation of the trajectory and of the radiation field. We show explicitly that the undulator radiation pattern is shift-invariant with respect to the electron trajectory angles, so that the emittance effects can be included without recomputing the radiation distribution. Furthermore, the time consuming computation of the undulator emission patterns is decoupled from the Monte Carlo sampling of the wavefront, leading to a very fast code. This is achieved by computing the three-dimensional source probability distribution function and by using an inversion algorithm to generate a random variate with the same distribution as the source. The physical basis of the code and the algorithm used are discussed in detail and some results presented

  10. Undulators at the ALS

    International Nuclear Information System (INIS)

    At Lawrence Berkeley Laboratory's (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/- 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10-11 Torr range and storage ring operating pressures with full current are in the low 10-10 Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented

  11. Desing considerations for a fast modulator in a 'crossed undulator'

    International Nuclear Information System (INIS)

    The modulator, a short electromagnetic wiggler, can be used to generate a phase shift between the synchrotron radiation of the two undulators in a crossed undulator. The switching frequency between two polarization states can be as high as 10 Hz. This paper discusses some physical requirements for the modulator and a conceptual design of the magnet for a crossed undulator at the Aladdin storage ring (Synchrotron Radiation center, University of Wisconsin, Madison) as a prototype development for the Advanced Light Source (ALS) and the Advanced Photon Source (APS)

  12. Tapered undulators for SASE FELs

    CERN Document Server

    Fawley, W M; Vinokurov, N A

    2002-01-01

    We discuss the use of tapered undulators to enhance the performance of free-electron lasers (FELs) based upon self-amplified spontaneous emission, where the radiation tends to have a relatively broad bandwidth and limited temporal coherence. Using the polychromatic FEL simulation code GINGER, we numerically demonstrate the effectiveness of tapered undulators for parameters corresponding to the Argonne low-energy undulator test line FEL and the proposed linac coherent light source.

  13. Thermal Tests of Undulator Quad

    International Nuclear Information System (INIS)

    Running at the nominal temperature, the undulator quadrupole has a several degree temperature increase. This note describes the test used to determine the effect on the undulator integrals from the temperature gradient caused by the heat from the quadrupole conducting down the beam pipe. The undulator quadrupoles running at their nominal current of 4 amps heat up approximately 4 degrees Celsius; this magnet in turn heats up the beampipe which goes into the undulator. The heating ends up introducing a thermal gradient across the undulator which causes small changes in the magnetic field of the heated poles. By measuring the temperature change in the poles we can model the effects on the field and determine what the magnetic errors will be.

  14. Properties of undulator radiation

    International Nuclear Information System (INIS)

    Properties of the radiation emitted by a plane sinusoidal undulator are calculated in the far field approximation. Software has been developed to calculate the spectral distribution and polarization of the radiated intensity I(E) at a point on (or integrated over) a cross sectional observation plane of the photon beam. Spatial distribution of monochromatic radiation and power density contours are also calculated. Spectral broadening caused by an electron beam of finite spatial distribution is considered. Dispersive properties of the photon beam, including the dependence on deflection parameter, are analyzed. It is shown that reasonably constant intensity distribution I(E) can be obtained by properly shaping the beam acceptance aperture. 5 refs., 11 figs

  15. Self-stimulated Emission of Undulator Radiation

    CERN Document Server

    Bessonov, E G; Mikhailichenko, A A; Osipov, A L

    2010-01-01

    We attract attention that interaction of particle in downstream undulator with its own wavelet emitted in upstream undulator could be as strong as with the frictional field in undulator itself. This phenomenon could be used for enhancement of signal from pickup undulators in optical stochastic cooling methods as well as for increase of damping.

  16. Undulator-based production of polarized positrons

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, G. [Tel-Aviv Univ. (Israel); Barley, J. [Cornell Univ., Ithaca, NY (United States); Batygin, Y. [SLAC, Menlo Park, CA (US)] (and others)

    2009-05-15

    Full exploitation of the physics potential of a future International Linear Collider will require the use of polarized electron and positron beams. Experiment E166 at the Stanford Linear Accelerator Center (SLAC) has demonstrated a scheme in which an electron beam passes through a helical undulator to generate photons (whose first-harmonic spectrum extended to 7.9 MeV) with circular polarization, which are then converted in a thin target to generate longitudinally polarized positrons and electrons. The experiment was carried out with a one-meter-long, 400-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) operated at 46.6 GeV. Measurements of the positron polarization have been performed at five positron energies from 4.5 to 7.5 MeV. In addition, the electron polarization has been determined at 6.7MeV, and the effect of operating the undulator with a ferrofluid was also investigated. To compare the measurements with expectations, detailed simulations were made with an upgraded version of GEANT4 that includes the dominant polarization-dependent interactions of electrons, positrons, and photons with matter. The measurements agree with calculations, corresponding to 80% polarization for positrons near 6 MeV and 90% for electrons near 7 MeV. (orig.)

  17. Undulator-Based Production of Polarized Positrons

    CERN Document Server

    Alexander, Gideon; Batygin, Yuri; Berridge, Steven; Bharadwaj, Vinod; Bower, Gary; Bugg, William; Decker, Franz-Josef; Dollan, Ralph; Efremenko, Yuri; Floettmann, Klaus; Gharibyan, Vahagn; Hast, Carsten; Iverson, Richard; Kolanoski, Hermann; Kovermann, Jan W; Laihem, Karim; Lohse, Thomas; McDonald, Kirk T; Mikhailichenko, Alexander A; Moortgat-Pick, Gudrid; Pahl, Philipp; Pitthan, Rainer; Poeschl, Roman; Reinherz-Aronis, Erez; Riemann, Sabine; Schaelicke, Andreas; Schueler, Klaus-Peter; Schweizer, Thomas; Scott, Duncan; Sheppard, John C; Stahl, Achim; Szalata, Zenon; Walz, Dieter R; Weidemann, Achim

    2009-01-01

    Full exploitation of the physics potential of a future International Linear Collider will require the use of polarized electron and positron beams. Experiment E166 at the Stanford Linear Accelerator Center (SLAC) has demonstrated a scheme in which an electron beam passes through a helical undulator to generate photons (whose first-harmonic spectrum extended to 7.9MeV) with circular polarization, which are then converted in a thin target to generate longitudinally polarized positrons and electrons. The experiment was carried out with a one-meter-long, 400-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) operated at 46.6GeV. Measurements of the positron polarization have been performed at five positron energies from 4.5 to 7.5MeV. In addition, the electron polarization has been determined at 6.7MeV, and the effect of operating the undulator with a ferrofluid was also investigated. To compare the measurements with expectations, detailed simulations were made with an upgraded version of Geant4...

  18. Numerical Modeling of Shoreline Undulations

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg

    The present thesis considers undulations on sandy shorelines. The aim of the study is to determine the physical mechanisms which govern the morphologic evolution of shoreline undulations, and thereby to be able to predict their shape, dimensions and evolution in time. In order to do so a numerical...... model has been developed which describes the longshore sediment transport along arbitrarily shaped shorelines. The numerical model is based on a spectral wave model, a depth integrated flow model, a wave-phase resolving sediment transport description and a one-line shoreline model. First the theoretical...... length of the shoreline undulations is determined in the linear regime using a shoreline stability analysis based on the numerical model. The analysis shows that the length of the undulations in the linear regime depends on the incoming wave conditions and on the coastal profile. For larger waves...

  19. APS undulator radiation: First results

    International Nuclear Information System (INIS)

    The first undulator radiation has been extracted from the Advanced Photon Source (APS). The results from the characterization of this radiation are very satisfactory. With the undulator set at a gap of 15.8 mm (K=1.61), harmonics as high as the 17th were observed using a crystal spectrometer. The angular distribution of the third-harmonic radiation was measured, and the source was imaged using a zone plate to determine the particle beam emittance. The horizontal beam emittance was found to be 6.9 ± 1.0 nm-rad, and the vertical emittance coupling was found to be less than 3%. The absolute spectral flux was measured over a wide range of photon energies, and it agrees remarkably well with the theoretical calculations based on the measured undulator magnetic field profile and the measured beam emittance. These results indicate that both the emittance of the electron beam and the undulator magnetic field quality exceed the original specifications

  20. Transition undulator radiation as bright infrared sources

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.J. [Lawrence Berkeley Lab., CA (United States)

    1995-02-01

    Undulator radiation contains, in addition to the usual component with narrow spectral features, a broad-band component in the low frequency region emitted in the near forward direction, peaked at an angle 1/{gamma}, where {gamma} is the relativistic factor. This component is referred to as the transition undulator radiation, as it is caused by the sudden change in the electron`s longitudinal velocity as it enters and leaves the undulator. The characteristic of the transition undulator radiation are analyzed and compared with the infrared radiation from the usual undulator harmonics and from bending magnets.

  1. Transition undulator radiation as bright infrared sources

    International Nuclear Information System (INIS)

    Undulator radiation contains, in addition to the usual component with narrow spectral features, a broad-band component in the low frequency region emitted in the near forward direction, peaked at an angle 1/γ, where γ is the relativistic factor. This component is referred to as the transition undulator radiation, as it is caused by the sudden change in the electron's longitudinal velocity as it enters and leaves the undulator. The characteristics of the transition undulator radiation are analyzed and compared with the infrared radiation from the usual undulator harmonics and from bending magnets

  2. Damping Undulators vs Damping Wigglers

    OpenAIRE

    Muchnoi, Nickolai

    2016-01-01

    Use of damping wigglers is a common technique for beam emittance reduction in the electron storage rings. The general approach to estimate damping effect is based on evaluation of several radiation integrals for a storage ring itself as well as for insertion devices. In this letter we show that a wiggler radiation integrals should be tweaked to account for the impact of lower harmonics of undulator radiation, which is an equivalent of Thomson scattering. Under certain conditions, these amendm...

  3. Observational constraints on undulant cosmologies

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela; /Valencia U.; Mena Requejo, Olga; Quigg, Chris; /Fermilab

    2005-10-01

    In an undulant universe, cosmic expansion is characterized by alternating periods of acceleration and deceleration. We examine cosmologies in which the dark-energy equation of state varies periodically with the number of e-foldings of the scale factor of the universe, and use observations to constrain the frequency of oscillation. We find a tension between a forceful response to the cosmic coincidence problem and the standard treatment of structure formation.

  4. Coherent radiation in an undulator

    Science.gov (United States)

    Chin, Yong Ho

    1990-12-01

    This paper is concerned with the synchrotron radiation from an undulating electron beam in a rectangular waveguide. The analysis is based on the dyadic Green's function approach to solve Maxwell's equations in terms of the vector potential. It is shown analytically and numerically that the radiated energy spectrum may differ significantly from the free space results when the undulator length divided by the Lorentz factor of the electron beam is larger than the transverse size of the waveguide. Then, the appearance of the spectrum is changed into a small number of sharp peaks, each corresponding to an excited waveguide mode. The undulator radiation is identified with the wake field in beam instabilities. The concepts of wake function and impedance are introduced to formulate the present problem in the same manner as the beam instability problem, so that the accumulated techniques of the latter can be applied. It is shown that the obtained impedances satisfy the Panofsky-Wenzel theorem and other properties inevitable for wake fields.

  5. Damping Undulators vs Damping Wigglers

    CERN Document Server

    Muchnoi, Nickolai

    2016-01-01

    Use of damping wigglers is a common technique for beam emittance reduction in the electron storage rings. The general approach to estimate damping effect is based on evaluation of several radiation integrals for a storage ring itself as well as for insertion devices. In this letter we show that a wiggler radiation integrals should be tweaked to account for the impact of lower harmonics of undulator radiation, which is an equivalent of Thomson scattering. Under certain conditions, these amendments play a decisive role in a formation of equilibrium emittance.

  6. Radiation emitted by transverse-gradient undulators

    Science.gov (United States)

    Bernhard, Axel; Braun, Nils; Rodríguez, Verónica Afonso; Peiffer, Peter; Rossmanith, Robert; Widmann, Christina; Scheer, Michael

    2016-09-01

    Conventional undulators are used in synchrotron light sources to produce radiation with a narrow relative spectral width as compared to bending magnets or wigglers. The spectral width of the radiation produced by conventional undulators is determined by the number of undulator periods and by the energy spread and emittance of the electron beam. In more compact electron sources like for instance laser plasma accelerators the energy spread becomes the dominating factor. Due to this effect these electron sources cannot in general be used for high-gain free electron lasers (FELs). In order to overcome this limitation, modified undulator schemes, so-called transverse gradient undulators (TGUs), were proposed and a first superconducting TGU was built at Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. In this paper simulations of the expected synchrotron radiation spectral distribution are presented. An experimental test with that device is under preparation at the laser wakefield accelerator at the JETI laser at the University of Jena, Germany.

  7. Undulator with dynamic compensation of magnetic forces

    Energy Technology Data Exchange (ETDEWEB)

    Gluskin, Efim; Trakhtenberg, Emil; Xu, Joseph Z.

    2016-05-31

    A method and apparatus for implementing dynamic compensation of magnetic forces for undulators are provided. An undulator includes a respective set of magnet arrays, each attached to a strongback, and placed on horizontal slides and positioned parallel relative to each other with a predetermined gap. Magnetic forces are compensated by a set of compensation springs placed along the strongback. The compensation springs are conical springs having exponential-force characteristics that substantially match undulator magnetic forces independently of the predetermined gap. The conical springs are positioned along the length of the magnets.

  8. Wakefield Undulator For Generating X-rays

    CERN Document Server

    Opanasenko, A N

    2004-01-01

    Conception of wakefield undulator (WFU) with very short period is presented. In the base of photon generation by the WFU lies a new mechanism of undulator-type radiation emitted by an ultrarelativistic electron bunch that undulates due to non-synchronous spatial harmonics of its wakefields while the bunch moves along a periodic waveguide. The creation of the WFU with sub-millimeter periods due to advanced accelerator technology opens possibilities to generate hard X-rays employing relatively low electron energies without external alternative fields.

  9. MaRIE Undulator & XFEL Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Laboratory; Marksteiner, Quinn R. [Los Alamos National Laboratory; Anisimov, Petr Mikhaylovich [Los Alamos National Laboratory; Buechler, Cynthia Eileen [Los Alamos National Laboratory

    2015-03-23

    The 22 slides in this presentation treat the subject under the following headings: MaRIE XFEL Performance Parameters, Input Electron Beam Parameters, Undulator Design, Genesis Simulations, Risks, and Summary It is concluded that time-dependent Genesis simulations show the MaRIE XFEL can deliver the number of photons within the required bandwidth, provided a number of assumptions are met; the highest risks are associated with the electron beam driving the XFEL undulator; and risks associated with the undulator and/or distributed seeding technique may be evaluated or retired by performing early validation experiments.

  10. Experience with small-gap undulators

    International Nuclear Information System (INIS)

    Over the past year, we have gained some experience with small-gap undulators through operation of the NSLS Prototype Small-Gap Undulator (PSGU). PSGU is a small R ampersand D insertion device intended for investigation of the fundamental limitations of small-gap devices. At the same time, PSGU aptly demonstrates the enhanced performance offered by such devices, through generation of radiation with a 16 mm period pure-permanent-magnet undulator. In what follows, we present a brief description of PSGU and a summary of operating experience to date. This includes a spectrum of the undulator radiation produced at a 5.6 mm magnet gap, and the appearance of operational limitations, namely lifetime degradation, beam instabilities, and increased bremsstrahlung radiation

  11. A preliminary design of a knot undulator.

    Science.gov (United States)

    Xi, Fuchun; Shi, Tan; Fan, Qingyan; Prestemon, Soren; Wan, Weishi; An, Zhenghua; Qiao, S

    2013-01-01

    The magnetic field configuration of the previously proposed knot undulator [Qiao et al. (2009). Rev. Sci. Instrum. 80, 085108] is realised in the design of a hybridized elliptically polarized undulator, which is presented. Although the details of the field distribution are not the same as those in the theoretical proposal, it is demonstrated that the practical knot undulator could work perfectly. In order to understand the minor discrepancies of the two, mathematical formulae of the synchrotron radiation are derived based on the Fourier transform of the magnetic field. From the results of calculations by simulation program, the discrepancies could be well interpreted by the corresponding formulae. The results show the importance of optimization of the end sections of the knot undulator to suppress the on-axis heat load. Furthermore, a study of the impact of the undulator on beam dynamics of the storage ring was conducted using the Shanghai Synchrotron Radiation Facility as an example and the results show that the knot undulator has little effect on the beam. PMID:23254667

  12. Positioning system for the LCLS undulator.

    Energy Technology Data Exchange (ETDEWEB)

    Trakhenberg, E. M.

    2002-09-12

    The Linac Coherent Light Source (LCLS) Project includes the undulator subsystem that has 33 undulator magnetic structures each 3.4 m long. Positioning of the LCLS undulators along the undulator line with an accuracy of 50 {micro}m in the vertical transverse direction is required. A prototype of the LCLS undulator has been built with a positioning system based on three stages with cam shafts. Each cam shaft produces reciprocating motion with a range of {+-}3 mm. A servomotor with integrated brake, incremental rotary encoder, servo amplifier, and controller is used with a 100:1 ratio gear box to drive each cam shaft. Resolution of the motion control is about 0.05 {micro}m. SmartMotors are connected in parallel through an RS-485 interface to the serial port of the computer. With this approach, the control system is easily expandable; up to 120 motors can be controlled with one serial port. Positioning accuracy of about 10 {micro}m for the LCLS undulator prototype is demonstrated.

  13. A New PLS-II In-Vacuum Undulator and Characterization of Undulator Radiation

    CERN Document Server

    Kim, D-E; Park, K-H; Seo, H-S; Ha, T; Jeong, Y-G; Han, H-S; Lee, W W; Huang, J-Y; Nam, S; Kim, K-R; Shin, S

    2016-01-01

    This paper describes the result of overall studies from development to characterization of undulator radiation. After three years of upgrading, PLS-II [1, 2] has been operating successfully since 21st March 2012. During the upgrade, we developed and installed an in-vacuum undulator (IVU) that generates brilliant X-ray beam. The IVU with 3 GeV electron beam generates undulator radiation up to ~ 21 keV using 11th higher harmonic. The characterizations of the undulator radiation at an X-ray beam line in PLS-II agreed well with the simulation. Based on this performance demonstration, the in-vacuum undulator is successfully operating at PLS-II.

  14. Interferometry using undulator sources (invited, abstract)

    Science.gov (United States)

    Beguiristain, R.; Goldberg, K. A.; Tejnil, E.; Bokor, J.; Medecki, H.; Attwood, D. T.; Jackson, K.

    1996-09-01

    Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in Soft X-Ray Projection Lithography, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), 18, 1089, and D. Attwood et al., Appl. Opt. 32, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg et al., in Extreme Ultra Lithography, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg et al., Proc. SPIE 2437, to be published, and K. Goldberg et al., J. Vac. Sci. Technol. B 13, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown.

  15. Optical Fibre Dosimeter for SASE FEL Undulators

    CERN Document Server

    Körfer, M

    2003-01-01

    Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is ...

  16. Coherent Radiation Effects in the LCLS Undulator

    CERN Document Server

    Reiche, Sven

    2004-01-01

    For X-ray Free-Electron Lasers, a change in the electron energy while amplifying the FEL radiation can shift the resonance condition out of the bandwidth of the FEL. The largest sources of energy loss is incoherent undulator radiation. Because the loss per electron depends only on the undulator parameters and the beam energy, which are fixed for a given resonant wavelength, the average energy loss can be compensated for by a fixed taper of the undulator. Coherent radiation has a strong enhancement proportional to the number of electrons in the bunch for wavelengths comparable to or longer than the bunch dimension or bunch sub-structures. If the coherent loss is comparable to that of the incoherent the required taper depends on the bunch charge and the applied compression scheme and a change of these parameters would require a change of the taper. This imposes a limitation on the operation of FELs, where the taper can only be adjusted manually. In this presentation we analyze the coherent emission of undulator...

  17. KIAE-1.5-3 undulator performance

    Energy Technology Data Exchange (ETDEWEB)

    Varfolomeev, A.A.; Ivanchenko, S.N.; Khlebnikov, A.S. [Kurchatov Institute, Moscow (Russian Federation)] [and others

    1995-12-31

    Hybrid type undulator with 60 periods of {lambda}{sub w} = 1.5 cm and tunable gap in wide range has been designed and manufactured. Additional side magnet arrays provide high magnetic field (near Halbach limit) along with transverse field profiles for e.b. focusing.

  18. Undulator Radiation Damage Experience at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, H. D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Field, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mao, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Levashov, Y. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Santana, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Welch, J. N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wolf, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-01-06

    The SLAC National Accelerator Laboratory has been running the Linac Coherent Light Source (LCLS), the first x-ray Free Electron Laser since 2009. Undulator magnet damage from radiation, produced by the electron beam traveling through the 133-m long straight vacuum tube, has been and is a concern. A damage measurement experiment has been performed in 2007 in order to obtain dose versus damage calibrations. Radiation reduction and detection devices have been integrated into the LCLS undulator system. The accumulated radiation dose rate was continuously monitored and recorded. In addition, undulator segments have been routinely removed from the beamline to be checked for magnetic (50 ppm, rms) and mechanic (about 0.25 µm, rms) changes. A reduction in strength of the undulator segments is being observed, at a level, which is now clearly above the noise. Recently, potential sources for the observed integrated radiation levels have been investigated. The paper discusses the results of these investigation as well as comparison between observed damage and measured dose accumulations and discusses, briefly, strategies for the new LCLS-II upgrade, which will be operating at more than 300 times larger beam rate.

  19. Generation and characterization of superradiant undulator radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bocek, D.

    1997-06-01

    High-power, pulsed, coherent, far-infrared (FIR) radiation has many scientific applications, such as pump-probe studies of surfaces, liquids, and solids, studies of high-T{sub c} superconductors, biophysics, plasma diagnostics, and excitation of Rydberg atoms. Few sources of such FIR radiation currently exist. Superradiant undulator radiation produced at the SUNSHINE (Stanford UNiversity SHort INtense Electron-source) is such a FIR source. First proposed in the mm-wave spectral range by Motz, superradiant undulator radiation has been realized in the 45 {micro}m to 300 {micro}m spectral range by using sub-picosecond electron bunches produced by the SUNSHINE facility. The experimental setup and measurements of this FIR radiation are reported in this thesis. In addition, to being a useful FIR source, the superradiant undulator radiation produced at SUNSHINE is an object of research in itself. Measured superlinear growth of the radiated energy along the undulator demonstrates the self-amplification of radiation by the electron bunch. This superlinear growth is seen at 47 {micro}m to 70 {micro}m wavelengths. These wavelengths are an order of magnitude shorter than in previous self-amplification demonstrations.

  20. Concept of quasi-periodic undulator - control of radiation spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Shigemi [Japan Atomic Energy Research Institute, Ibaraki (Japan)

    1995-02-01

    A new type of undulator, the quasi-periodic undulator (QPU) is considered which generates the irrational harmonics in the radiation spectrum. This undulator consists of the arrays of magnet blocks aligned in a quasi-periodic order, and consequentially lead to a quasi-periodic motion of electron. A combination of the QPU and a conventional crystal/grating monochromator provides pure monochromatic photon beam for synchrotron radiation users because the irrational harmonics do not be diffracted in the same direction by a monochromator. The radiation power and width of each radiation peak emitted from this undulator are expected to be comparable with those of the conventional periodic undulator.

  1. An experimental superconducting helical undulator

    Energy Technology Data Exchange (ETDEWEB)

    Caspi, S.; Taylor, C. [Lawrence Berkeley Lab., CA (United States)

    1995-12-31

    Improvements in the technology of superconducting magnets for high energy physics and recent advancements in SC materials with the artificial pinning centers (APC){sup 2}, have made a bifilar helical SC device an attractive candidate for a single-pass free electron laser (FEL){sup 3}. Initial studies have suggested that a 6.5 mm inner diameter helical device, with a 27 mm period, can generate a central field of 2-2.5 Tesla. Additional studies have also suggested that with a stored energy of 300 J/m, such a device can be made self-protecting in the event of a quench. However, since the most critical area associated with high current density SC magnets is connected with quenching and training, a short experimental device will have to be built and tested. In this paper we discuss technical issues relevant to the construction of such a device, including a conceptual design, fields, and forces.

  2. Exact relativistic theory of geoid's undulation

    CERN Document Server

    Kopeikin, Sergei; Karpik, Alexander

    2014-01-01

    Precise determination of geoid is one of the most important problem of physical geodesy. The present paper extends the Newtonian concept of the geoid to the realm of Einstein's general relativity and derives an exact relativistic equation for the unperturbed geoid and level surfaces under assumption of axisymmetric distribution of background matter in the core and mantle of the Earth. We consider Earth's crust as a small disturbance imposed on the background distribution of matter, and formulate the master equation for the anomalous gravity potential caused by this disturbance. We find out the gauge condition that drastically simplifies the master equation for the anomalous gravitational potential and reduces it to the form closely resembling the one in the Newtonian theory. The master equation gives access to the precise calculation of geoid's undulation with the full account for relativistic effects not limited to the post-Newtonian approximation. The geoid undulation theory, given in the present paper, uti...

  3. Thermal analysis of superconducting undulator cryomodules

    Science.gov (United States)

    Shiroyanagi, Y.; Doose, C.; Fuerst, J.; Harkay, K.; Hasse, Q.; Ivanyushenkov, Y.; Kasa, M.

    2015-12-01

    A cryocooler-cooled superconducting undulator (SCU0) has been operating in the Advanced Photon Source (APS) storage ring since January of 2013. Based on lessons learned from the construction and operation of SCU0, a second superconducting undulator (SCU1) has been built and cold tested stand-alone. An excess cooling capacity measurement and static heat load analysis show a large improvement of cryogenic performance of SCU1 compared with SCU0. ANSYS-based thermal analysis of these cryomodules incorporating all the cooling circuits was completed. Comparisons between measured and calculated temperatures at the three operating conditions of the cryomodule (static, beam heat only, beam heat and magnet current) will be presented.

  4. Conceptual design of a plasma undulator

    Science.gov (United States)

    Suzuki, Yasuo

    1993-07-01

    A micropitched plasma undulator is proposed for the first time. It is composed of an array of hundreds of discharged and pinched slender columns of plasma. Two kinds of undulating forces on the electron beam can be considered: one is a periodic magnetic field generated by the electric currents flowing through the array of the small radius plasma columns and the other is a periodic electrostatic field generated by the interaction of the relativistic electron beam with the rippled density of the plasma. Methods for both producing and stabilizing the array of the plasma columns are discussed. The effects of collisions between the plasma particles and the electron beam on the orbit and the momentum of the electrons are also discussed, leading to the conclusion that they can be negligibly small, as far as the gas pressure in the chamber leaking from the plasma region does not disturb the performance of the electron accelerator.

  5. In vacuum undulator task force report

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; Kao, C.C.; Stefan, P. [and others

    1998-06-01

    Historically the NSLS has been active in R&D for state-of-the-art electron beams, photon beams and x-ray optics. One of the available straight sections has therefore been dedicated to insertion device R&D. Over the past five to seven years a program aimed at exploiting the very small vertical {beta} function in the straight sections has yielded first a prototype small gap undulator (PSGU) and then an in-vacuum undulator (IVUN). The IVUN sources attain a brightness similar to the existing hybrid wigglers in X21 and X25. They radiate significantly lower total power than the wigglers but produce higher power densities. They provide undulator rather than wiggler spectra. Because of the small gaps and small periods there is not much tunability in these devices and they will have to be purpose-built for a specific scientific program. The original IVUN parameters were chosen for in-elastic x-ray scattering, similar to the scientific program on X21. This put the fundamental at 4.6 keV and the third harmonic at 13.8 keV. The question that this new possible insertion device poses is what science programs can best take advantage of this new insertion device source? To answer this, a task force was formed by M. Hart, NSLS Department Chair and charged with identifying viable scientific programs that could seek outside funding to construct IVUN beamlines. The task force concentrated on experimental programs that are presently being pursued on new insertion devices worldwide. For example, x-ray photon correlation spectroscopy, which takes advantage of the large coherent flux from undulator sources, was considered. However, this program was not considered as the highest priority. The general area of protein crystallography, however, is ideal for the IVUN source. The unique electron beam optics that makes the IVUN possible in the first place also makes the IVUN ideal as a source for microdiffraction.

  6. Feasibility of Diagnostics Undulator Studies at ASTA

    OpenAIRE

    Lumpkin, A. H.; Wendt, M.; Byrd, J. M.

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermilab. With a 1-ms macropulse composed of up to 3000 micropulses and with beam energies projected from 45 to 800 MeV, the need for non-intercepting diagnostics for beam size, position, energy, and bunch length is clear. In addition to the rf BPMs, optical synchrotron radiation (OSR), and optical diffraction radiation (ODR) techniques already planned, we propose the use of undulator radiation fr...

  7. Operation of the ANKA Synchrotron Light Source with Superconductive Undulators

    CERN Document Server

    Rossmanith, Robert; Bernhard, Axel; Hagelstein, Michael; Kostka, Barbara; Steffens, Erhard; Weisser, Matthias; Wollmann, D

    2005-01-01

    The synchrotron light source ANKA (2.5 GeV, 200 mA) is a versatile multi-purpose storage ring with beam lines for coherent IR and THz radiation (IR-laser), LIGA applications and high brilliance X-rays. It is now plannned to install in addition several superconductive undulators for a wide range of applications: fast tunable X-rays for material research, imaging applications and an undulator with variable polarization direction for a dichroism beamline. This development of ANKA is the result of successful research on superconductive undulators which surpass the performance of permanent undulators by far (collaboration between ANKA, the University of Karlsruhe and the University of Erlangen-Nürnberg). The basic layout of the undulators and the required changes to a storage ring to accommodate the superconductive undulators is described in this paper.

  8. Undulator systems for the TESLA X-FEL

    International Nuclear Information System (INIS)

    A large X-ray FEL lab is under consideration within the TESLA project and is supposed to be operated in parallel with the TESLA linear collider. There will be five SASE FELs and five conventional spontaneous undulators. A conceptual design study has been made for the undulator systems for these X-FELs. It includes segmentation into 6.1 m long undulator 'cells'. Each consists of a 5 m long undulator 'segment', a separate quadrupole, one horizontal and one vertical corrector, and a phase shifter. These items are presented and discussed

  9. Research on Complexity of Surface Undulating Shapes of Rock Joints

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The surface undulating shapes of rock joints have been described qualitatively or experimental-quantitatively for a long time. The non-determined describing method can not fit quantitative evaluation of mechanical parameters of rock joints in engineering. In this paper, relative amplitude (RA) is chosen as a quantitative-describing index of surface measurement of 1 023 surface undulating curves which conducted by profile curve device(PCD). We discuss the nonuniformity,anisotropy and unhomogeneity of surface undulating shapes of joints. A new method that analyzes the complexity of surface undulating shapes of rock joints directional-statistically in various rock joints is also put forward.

  10. Undulator radiation carrying spin and orbital angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Shigemi [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)], E-mail: sasaki@aps.anl.gov; McNulty, Ian; Dejus, Roger [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2007-11-11

    We show that the radiation from a helical undulator not only carries spin angular momentum (circular polarization) but also orbital angular momentum. This exotic property of the undulator radiation may be useful in coherent X-ray imaging and scattering experiments and to probe electronic transitions in matter by orbital dichroism spectroscopy. Also, we present that a new magnet configuration, similar to the structure of Figure-8 undulator or the PERA undulator, may generate right- and left-hand circularly polarized off-axis radiation simultaneously.

  11. Undulator radiation carrying spin and orbital angular momentum.

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S.; McNulty, I.; Dejus, R.; X-Ray Science Division

    2007-11-11

    We show that the radiation from a helical undulator not only carries spin angular momentum (circular polarization) but also orbital angular momentum. This exotic property of the undulator radiation may be useful in coherent X-ray imaging and scattering experiments and to probe electronic transitions in matter by orbital dichroism spectroscopy. Also, we present that a new magnet configuration, similar to the structure of Figure-8 undulator or the PERA undulator, may generate right- and left-hand circularly polarized off-axis radiation simultaneously.

  12. Undulations from amplified low frequency surface waves

    CERN Document Server

    Coutant, Antonin

    2012-01-01

    We study the scattering of gravity waves in longitudinal stationary flows. When the flow velocity becomes supercritical, counterflow propagating waves are amplified in such a way that, in the zero-frequency limit, the free surface develops an undu- lation, i.e., a zero-frequency wave of large amplitude with nodes located at specific places. From this, we show that the unperturbed flat surface is unstable against perturbations of arbitrary small amplitude. We then show that this instability also appears when treating low frequency waves by a stochastic ensemble. The relation between the generation of undulations and black hole radiation (the Hawking effect) is discussed.

  13. LCLS Undulator Commissioning, Alignment, and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, Heinz-Dieter

    2009-10-30

    The LCLS x-ray FEL has recently achieved its 1.5-Angstrom lasing and saturation goals upon first trial. This was achieved as a result of a thorough pre-beam checkout, both traditional and beam-based component alignment techniques, and high electron beam brightness. The x-ray FEL process demands very tight tolerances on the straightness of the electron beam trajectory (<5 {micro}m) through the LCLS undulator system. Tight, but less stringent tolerances of {approx}100 {micro}m rms were met for the transverse placement of the individual undulator segments with respect to the beam axis. The tolerances for electron beam straightness can only be met through a beam-based alignment (BBA) method, which is implemented using large electron energy variations and sub-micron resolution cavity beam position monitors (BPM), with precise conventional alignment used to set the starting conditions. Precision-fiducialization of components mounted on remotely adjustable girders, and special beam-finder wires (BFW) at each girder have been used to meet these challenging alignment tolerances. Longer-term girder movement due to ground motion and temperature changes are being monitored, continuously, by a unique stretched wire and hydrostatic level Alignment Diagnostics System (ADS).

  14. Cosmological constraints on the Undulant Universe

    Institute of Scientific and Technical Information of China (English)

    Tian Lan; Yan Gong; Hao-Yi Wan; Tong-Jie Zhang

    2010-01-01

    We use the redshifi Hubble parameter H(z)data derived from relative galaxy ages,distant type Ⅰa supernovae(SNe Ⅰa),the Baryonic Acoustic Oscillation (BAO)peak,and the Cosmic Microwave Background(CMB)shift parameter data,to constrain cosmological parameters in the Undulant Universe.We marginalize the likelihood functions over h by integrating the probability density P ∝ e-x2/2.By using a Markov Chain Monte Carlo(MCMC)technique,we obtain the best fitting results and give the confidence regions in the b-Ωm0 plane.Then we compare their constraints.Our results show that the H(z)data play a similar role with the SNe Ia data in cosmological study.By presenting the independent and joint constraints,we find that the BAO and CMB data play very important roles in breaking the degeneracy compared with the H(z)and SNe Ⅰa data alone.Combined with the BAO or CMB data,one can remarkably improve the constraints.The SNe Ia data sets constrain Ωm0 much tighter than the H(z)data sets,but the H(z)data sets constrain b much tighter than the SNe Ⅰa data sets.All these results show that the Undulant Universe approaches the ACDM model.We expect more H(z)data to constrain cosmological parameters in the future.

  15. The adjustable phase planar helical undulator

    International Nuclear Information System (INIS)

    The study of magnetic and biological materials which exhibit magnetic circular dichroism has created a demand for circularly polarized x-rays whose helicity may be switched between the right and left hand senses. At present, circularly polarized x-rays are obtained from storage ring bending magnets by accepting radiation from above and below the axis, but insertion device sources are desired for greater intensity. Planar helical undulators are magnetic insertion devices that generate helical magnetic fields. The charged particle beam executes a helical trajectory in the device, and produces elliptically polarized x-rays. The special case of circularly polarized x-rays is most in demand. We present here the design description of a new type of planar helical undulator, which we are constructing for the SPEAR storage ring at the Stanford Synchrotron Radiation Laboratory (SSRL). It comprises four rows of pure permanent magnet blocks, one row in each quadrant about the axis defined by the electron beam. Rows may be translated longitudinally with respect to each other to change the helicity of the magnetic field they create at the position of the beam. They may also be translated longitudinally to vary the energy of the x-rays emitted, unlike designs where this function is performed by varying the gap between the rows. This work includes numerical calculations of the fields, electron trajectories, x-ray spectra, off-axis effects, and mechanical design considerations

  16. Resistive Wall Wakefield in the LCLS Undulator

    CERN Document Server

    Bane, Karl Leopold Freitag

    2005-01-01

    In the Linac Coherent Light Source (LCLS), a short, intense bunch (rms length 20 microns, bunch charge 1 nC) will pass through a small, long undulator beam pipe (radius 2.5 mm, length 130 m). The wakefields in the undulator, particularly the resistive wall wake of the beam pipe, will induce an energy variation along the bunch, a variation that needs to be kept to within a few times the Pierce parameter for all beam particles to continue to lase. Earlier calculations included the short-range resistive wall wake, but did not include the frequency dependence of conductivity (ac conductivity) of the beam pipe walls. We show that for copper and for the LCLS bunch structure, including the ac conductivity results in a very large effect. We show that the effect can be ameliorated by choosing aluminum and also by taking a flat, rather than round, beam pipe chamber (if the vertical aperture is fixed). The effect of the (high frequency) anomalous skin effect is also considered.

  17. Short-Period RF Undulator for a SASE Nanometer source

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2001-12-21

    Analysis is described towards development of a RF undulator with a period < 1 cm, an undulator parameter K of the order of unity, and a gap greater than 2.25 mm. The application for the undulator is for a SASE source to produce 1 nm wavelength radiation using a low energy electron beam in the range 1-2 GeV. Particle orbit calculations in a conventional standing-wave resonator configuration show that the presence of a co-propagating component of RF field can cause deleterious motion for the undulating electrons that can seriously degrade their radiation spectrum. To obviate this problem, resonator designs were devised in which only the counter-propagating field components interact with the particles. Two resonator configurations with the same undulator parameter K = 0.4 have been devised and are described in this report.

  18. Auroral Undulations During Magnetic Storms: TIMED/GUVI Observations

    Science.gov (United States)

    Zhang, Y.; Paxton, L. J.; Morrison, D.; Lui, T.; Kil, H.; Wolven, B.; Meng, C. I.

    2005-05-01

    Giant undulations on the equatorward edge of the diffuse aurora have been identified in TIMED/GUVI auroral images in the far ultraviolet wavelengths. Some new features have been observed: (1) The GUVI 121.6nm auroral images provide direct optical evidence that the undulations occur in the proton aurora, (2) Undulations are not limited to the dusk sector, they can occur in all local time sectors, (3) Both large ionospheric ion drift velocity (1000 m/s and above) and strong velocity shear (> 0.1 1/s) appear to be a necessary condition for the undulation to occur, (4) While almost all of the undulation events are observed during magnetic storms (Dst K-H instability.

  19. Feasibility of Diagnostics Undulator Studies at ASTA

    CERN Document Server

    Lumpkin, A H; Byrd, J M

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermilab. With a 1-ms macropulse composed of up to 3000 micropulses and with beam energies projected from 45 to 800 MeV, the need for non-intercepting diagnostics for beam size, position, energy, and bunch length is clear. In addition to the rf BPMs, optical synchrotron radiation (OSR), and optical diffraction radiation (ODR) techniques already planned, we propose the use of undulator radiation from a dedicated device for diagnostics. with a nominal period of 4-5 cm, a tunable field parameter K, and a length of several meters. The feasibility of extending such techniques in the visible regime at a beam energy of 125 MeV into the UV and VUV regimes with beam energies of 250 and 500 MeV will be presented.

  20. Spontaneous emission spectra from a staggered-array undulator

    International Nuclear Information System (INIS)

    A staggered-array undulator set inside the superconducting solenoid coils is shown to be able to provide high undulator fields larger than the longitudinal magnetic fields, a small undulator period, easy tunability through the solenoid coil current, and compact and easy fabrication. The overall performance characteristics of this undulator were studied mainly with respect to iron and aluminum disk widths, and spontaneous emission spectra through the numerical calculations. The maximum undulator field is found to be obtained for the ratio of the aluminum disk width to the undulator period of 0.45. The line widths (FWHM) of the spontaneous emission spectra, however, do not show Nw-1 dependence on the number of the undulator period Nw for practical beams with a Gaussian distribution, compared with for a single electron. The energy spread among various parameters is seen to play an important role in reducing the FWHM with increase of Nw. The large tunability of the wavelength is proved to cover 6-10 mm by changing the solenoid magnetic field from 0.4 T to 1.6 T. (author)

  1. Effects of Tapered Betafunction in the LCLS Undulators

    CERN Document Server

    Goldammer, K; Huang, Z

    2005-01-01

    The Linac coherent Light Source (LCLS) is an x-ray free-electron laser (FEL) project based on the SLAC linac. With its nominal set of electron beam, focusing and undulator parameters, it is designed to achieve SASE saturation at an undulator length of about 100m with an average power of 10GW. In order to keep the electron beam focused in the undulators, a FODO lattice is integrated along the entire length of the undulators. Nominally, the quadrupoles strengths are chosen to produce nearly constant beta function and beam size along the undulator, optimized for the FEL interaction in the exponential growth regime. Since these quadrupoles are electromagnetic, it is possible to adjust the individual quadrupole strength to vary the beta function and the beam size along the undulator, tailoring the FEL interaction in the startup and the saturation regimes. In this paper, we present simulation studies of the tapered beta function in the LCLS undulator and discuss the generated x-ray properties.

  2. Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, Heinz Dieter; Gassner, Georg; Peters, Franz; /SLAC

    2012-03-26

    X-ray FELs demand that the positions of undulator components be stable to less than 1 {mu}m per day. Simultaneously, the undulator length increases significantly in order to saturate at x-ray wavelengths. To minimize the impact of the outside environment, the Linac Coherent Light Source (LCLS) undulator is placed underground, but reliable data about ground motion inside such a tunnel was not available in the required stability range during the planning phase. Therefore, a new position monitor system had been developed and installed with the LCLS undulator. This system is capable of measuring x, y, roll, pitch and yaw of each of the 33 undulator quadrupoles with respect to stretched wires. Instrument resolution is about 10 nm and instrument drift is negligible. Position data of individual quadrupoles can be correlated along the entire 132-m long undulator. The system has been under continuous operation since 2009. This report describes long term experiences with the running system and the observed positional stability of the undulator quadrupoles.

  3. Free Electron Lasers with Slowly Varying Beam and Undulator Parameters

    CERN Document Server

    Huang, Zhirong

    2005-01-01

    The performance of a free electron lasers (FEL) is affected when the electron beam energy varies alone the undulator as would be caused by vacuum pipe wakefields and/or when the undulator strength parameter is tapered in the small signal regime until FEL saturation. In this paper, we present a self-consistent theory of FELs with slowly-varying beam and undulator parameters. A general method is developed to apply the WKB approximation to the beam-radiation system by employing the adjoint eigenvector that is orthogonal to the eigenfunctions of the coupled Maxwell-Vlasov equations. This method may be useful for other slowly varying processes in beam dynamics.

  4. Optics Concept for a Pair of Undulator Beamlines for MX*

    OpenAIRE

    Berman, L. E.; Allaire, M; Chance, M R; Hendrickson, W A; Héroux, A; Jakoncic, J.; Liu, Q.; Orville, A.M.; Robinson, H.H.; Schneider, D. K.; SHI, W.; Soares, A.S.; Stojanoff, V.; Stoner-Ma, D.; Sweet, R M

    2011-01-01

    We describe a concept for x-ray optics to feed a pair of macromolecular crystallography (MX) beamlines which view canted undulator radiation sources in the same storage ring straight section. It can be deployed at NSLS-II and at other low-emittance third-generation synchrotron radiation sources where canted undulators are permitted, and makes the most of these sources and beamline floor space, even when the horizontal angle between the two canted undulator emissions is as little as 1-2 mrad. ...

  5. First test results for an adjustable phase undulator

    International Nuclear Information System (INIS)

    An Adjustable Phase Undulator (APU) was installed and tested on the beamline 5 of the SPEAR storage ring. The APU has the same magnetic structure as a conventional adjustable gap undulator (AGU), but its magnetic field is varied by changing the longitudinal position between the rows of magnets, while keeping the gap between them fixed. The tests described here show that this undulator performs according to theoretical predictions and numerical models. The main reason to consider a phase adjustable design is the substantial reduction in size, complexity, and cost over comparable conventional designs. (author) 4 refs.; 3 figs

  6. A Comparison of Geoid Undulations for West Central Greenland

    Science.gov (United States)

    Roman, Daniel R.; Csatho, Beata; Jezek, Kenneth C.; Thomas, Robert H.; Krabill, William B.; vonFrese, Ralph R. B.; Forsberg, Rene

    1997-01-01

    The accuracy of a new local gravity field model, GEOID94A, is examined at a site on the western Greenland ice sheet. The model, developed by the Danish National Survey and Cadastre, incorporates several new gravity data sets including an extensive amount of airborne gravity data. Model-derived geoid undulations were compared to independently determined undulations found by differencing the elevations from Global Positioning System controlled airborne laser altimetry and optical leveling surveys. Differences between the two sets of undulations were less than +/- 6 cm RMS. The comparison improved (+/- 5 cm RMS) when GEOID94A undulations were adjusted by local gravity observations also acquired at the site. Our comparisons demonstrate that GEOID94A adequately models the long to intermediate wavelengths of the gravity field. We conclude that GEOID94A constitutes a reliable reference model for studies of Greenland's gravity field.

  7. Undulation frequency affects burial performance in living and model flatfishes.

    Science.gov (United States)

    McKee, Amberle; MacDonald, Ian; Farina, Stacy C; Summers, Adam P

    2016-04-01

    Flatfishes bury themselves under a thin layer of sand to hide from predators or to ambush prey. We investigated the role of undulation frequency of the body in burial in five species of flatfishes (Isopsetta isolepis, Lepidopsetta bilineata, Hippoglossoides elassodon, Parophrys vetulus, and Psettichthys melanostictus). High-speed videos show that undulations begin cranially and pass caudally while burying, as in forward swimming in many other fishes. The flatfishes also flick the posterior edge of their dorsal and anal fins during burial, which may increase the total surface area covered by substrate. We built a simple physical model - a flexible, oval silicone plate with a motorized, variable-speed actuator - to isolate the effect of undulation frequency on burial. In both the model and actuated dead flatfish, increased undulation frequency resulted in an increase in the area of sand coverage. Complete coverage required an undulation frequency of no more than 10Hz for our models, and that was also sufficient for live flatfishes. The model shows that undulation is sufficient to bury the animal, but live flatfishes showed a superior ability to bury, which we attribute to the action of the median fins. PMID:26763759

  8. Design of an x-ray free electron laser undulator

    International Nuclear Information System (INIS)

    An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FEL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. We shall consider the case of the Linear Coherent Light Source (LCLS) FEL project at SLAC, which is intended to create 1.5 A x-rays using an electron beam with 15 GeV energy, 1.5π mm-mrad normalized emittance, 3400 A peak current, and 280 fsec FWHM bunch duration. We find that this 65 μm rms diameter beam must overlap its radiation with a walkoff of no more than 5 μm for efficient gain. This places severe limitations on the magnetic field errors and other mechanical tolerances. The following is a discussion of the undulator design, specifications, alignment, engineering, and beam position monitoring we plan to implement for the LCLS X-ray FEL

  9. Design of an x-ray free electron laser undulator

    International Nuclear Information System (INIS)

    An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FeL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. The authors shall consider the case of the Linear Coherent Light Source (LCLS) FEL project at SLAC, which is intended to create 1.5 angstrom x-rays using an electron beam with 15 GeV energy, 1.5π mm-mrad normalized emittance, 3,400 A peak current, and 280 fsec FWHM bunch duration. They find that this 65 microm rms diameter beam must overlap its radiation with a walkfoff of no more than 5 microm for efficient gain. This places severe limitations on the magnetic field errors and other mechanical tolerances. The following is a discussion of the undulator design, specifications, alignment, engineering, and beam position monitoring they plan to implement for the LCLS X-ray FEL

  10. Phase error reduction in superconductive undulators using induction shimming

    Energy Technology Data Exchange (ETDEWEB)

    Drayer, Elisabeth; Bernhard, Axel; Afonso Rodriguez, Veronica; Grau, Andreas; Peiffer, Peter; Widmann, Christina; Baumbach, Tilo [KIT, Karlsruhe (Germany)

    2013-07-01

    The reduction of field errors in superconductive undulators is more demanding than in room temperature permanent magnet undulators. Various basic concepts exist but most of them have the disadvantage that they require field measurements at liquid-Helium temperature and modifications of the undulator coils at room temperature. Thus one or more thermal cycles are needed for an iterative improvement of the field quality. In order to avoid such a procedure it was proposed to cover the undulator coils with a thin layer of coupled superconductive loops which passively compensate the field errors via induction of persistent correction currents. In previous measurements this concept proved to work in principle and conclusions on an optimised shim configuration and field measurement setup could be drawn. In this paper we present the results of new measurements using one 12-period superconductive undulator short model and applying an optimised induction shim configuration. Due to further improvements of the field measurement setup these experiments for the first time give a quantitative indication of the phase error reduction efficiency of induction shimming.

  11. Superradiance in an undulator in dual resonance mode

    Science.gov (United States)

    Bogdankevich, L. S.; Gelkhviidze, L. K.; Ivanov, V. S.; Krementsov, S. I.; Rayzer, M. D.; Rukhadze, A. A.; Fedotov, A. V.

    1986-01-01

    The emission of a relativistic electron beam in a linearly polarized undulator magnetic field is investigated experimentally and theoretically. The Terek-I high current accelerator was employed as the electron beam injector. A spatially periodic magnetic field was formed by a system of copper rings within the external pulse magnetic field. The resonance conditions for the longitudinal and transverse components of the magnetic field are investigated. Current transmission is found to be strongly dependent on the angle between the axis of the undulator and the axis of the solenoid. A system of equations is derived for the movement of a relativistic electron in the magnetic field of the undulator. The experimentally observed values of the resonant longitudinal magnetic field, the width of the resonant region, the transverse velocity of the electrons, and the radiation line width are explained analytically.

  12. Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Lai-bing Jia; Shi-wu Zhang; Jie Yang; K.H.Low

    2007-01-01

    Biomimetic design employs the principles of nature to solve engineering problems.Such designs which are hoped to be quick,efficient,robust,and versatile,have taken advantage of optimization via natural selection.In the present research.an environment-friendly propulsion system mimicking undulating fins of stingray was built.A non-conventional method was considered to model the flexibility of the fins of stingray.A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin.The driving linkages were used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fins.Owing to the modularity of the design of the mechanical fin,various undulating patterns can be realized.Some qualitative observations,obtained by experiments,predicted that the thrusts produced by the mechanical fin are different among various undulating patterns.To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system.Here,four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics(CFD)method.An unstructured,grid-based,unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles.The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into lift and thrust.The pressure force and friction force were also computed throughout the swimming cycle.Finally,vortex contour maps of these four basic fin undulating patterns were displayed and compared.

  13. Commissioning of the Delta Polarizing Undulator at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, Heinz-Dieter

    2015-09-25

    The Linac Coherent Light Source (LCLS) generates linearly polarized, intense, high-brightness x-ray pulses from planar fixed-gap undulators. While the fixed-gap design supports a very successful and tightly controlled alignment concept, it provides only limited taper capability (up to 1% through canted pole and horizontal position adjustability) and lacks polarization control. The latter is of great importance for soft x-ray experiments. A new 3.2-m-long compact undulator (based on the Cornell University Delta design) has been developed and installed in place of the last LCLS undulator segment (U33) in October 2014. This undulator provides full control of the polarization degree and K value. Used on its own, it produces fully polarized radiation in the selected state (linear, circular or elliptical) but at low intensity. To increase the output power by orders of magnitude, the electron beam is micro-bunched by several (~10) of the upstream LCLS undulator segments operated in the linear FEL regime. As unavoidable by-product, this microbunching process produces moderate amounts of horizontally linear polarized radiation which mixes with the radiation produced by the Delta undulator. This unwanted radiation component has been greatly reduced by the reverse taper configuration, as suggested by E. Schneidmiller and M. Yurkov. Full elimination of the linear polarized component was achieved through spatial separation combined with transverse collimation. The paper describes these and other methods tested during commissioning. It also presents results of polarization measurements showing high degrees of circular polarization in the soft x-ray wavelength range (500 eV - 1500 eV).

  14. Coherent harmonic production using a two-section undulator FEL

    Energy Technology Data Exchange (ETDEWEB)

    Jaroszynski, D.A. [Commissariat a l`Energie, Bruyeres-le-Chatel (France); Prazeres, R.; Glotin, F. [Centre Universitaire Paris-Sud (France)] [and others

    1995-12-31

    We present measurements and a theoretical analysis of a new method of generating harmonic radiation in a free-electron laser oscillator with a two section undulator in a single optical cavity. To produce coherent harmonic radiation the undulator is arranged so that the downstream undulator section resonance frequency matches a harmonic of the upstream undulator. Both the fundamental and the harmonic optical fields evolve in the same optical cavity and are coupled out with different extraction fractions using a hole in one of the cavity mirrors. We present measurements that show that the optical power at the second and third harmonic can be enhanced by more than an order of magnitude in this fundamental/harmonic configuration. We compare the production of harmonic radiation of a two sectioned fundamental/harmonic undulator with that produced from a FEL operating at its highest efficiency with a step-tapered undulator, where the bunching at the end of the first section is very large. We examine, the dependence of the harmonic power on the intracavity power by adjusting the optical cavity desynchronism, {delta}L. We also examine the evolution of the fundamental and harmonic powers as a function of cavity roundtrip number to evaluate the importance of the small signal gain at the harmonic. We compare our measurements with predictions of a multi-electron numerical model that follows the evolution of fundamental and harmonic power to saturation. This fundamental/harmonic mode, of operation of the FEL may have useful applications in the production of coherent X-ray and VUV radiation, a spectral range where high reflectivity optical cavity mirrors are difficult or impossible to manufacture.

  15. Numerical modeling of shoreline undulations part 1: Constant wave climate

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen

    2013-01-01

    This paper presents a numerical study of the non-linear development of alongshore undulations up to fully developed quasi-steady equilibrium. A numerical model which describes the longshore sediment transport along arbitrarily shaped shorelines is applied, based on a spectral wave model, a depth...... integrated flow model, a wave-phase resolving sediment transport description and a one-line shoreline model.First the length of the shoreline undulations is determined in the linear regime using a stability analysis. Next the further evolution from the linear to the fully non-linear regime is described. In...

  16. Experimental Study For The Feasibility Of A Crystalline Undulator

    CERN Document Server

    Bellucci, S; Biryukov, V M; Chesnokov, Yu A; Dabagov, S B; Giannini, G; Guidi, V; Ivanov, Y M; Kotov, V I; Maisheev, V A; Malagu, C; Martinelli, G; Petrunin, A A; Skorobogatov, V V; Stefancich, M; Vincenzi, D; Chesnokov, Yu.A.; Ivanov, Yu.M.

    2003-01-01

    We present an idea for creation of a crystalline undulator and report its first realization. One face of a silicon crystal was given periodic micro-scratches (trenches) by means of a diamond blade. The X-ray tests of the crystal deformation due to given periodic pattern of surface scratches have shown that a sinusoidal shape is observed on both the scratched surface and the opposite (unscratched) face of the crystal, that is, a periodic sinusoidal deformation goes through the bulk of the crystal. This opens up the possibility for experiments with high-energy particles channeled in crystalline undulator, a novel compact source of radiation.

  17. Coherent effects of a macro-bunch in an undulator

    CERN Document Server

    Dohlus, M; Limberg, T

    2000-01-01

    The longitudinal radiative force of an electron bunch moving in an undulator has been investigated in [1] assuming an 1D density distribution. To obtain the contribution of pure curvature effects and to avoid singular fields, the 1D linear motion field was subtracted. To relate these results to the 3D case we present analytical and numerical field calculations using the field solver of TRAFIC4. The 1D and 3D cases have been calculated in the transient regime, the steady-state regime and the steady-state regime averaged over one undulator period for the 1 GeV parameter set of the TESLA FEL.

  18. Spontaneous radiation from relativistic electrons in a tapered Apple-Ⅱ undulator

    Institute of Scientific and Technical Information of China (English)

    CHEN Mingzhi; HE Jianhua

    2009-01-01

    This paper presents most properties of radiation from a tapered Apple-Ⅱ undulator.The study demonstrates that tapering an Apple-Ⅱ undulator can broaden the harmonic bandwidth and the performance of polarization is also excellent at the broadened energy range.So Apple-Ⅱ undulator can be tapered to provide more convenience for energy scan experiment.

  19. Test of an undulated vacuum chamber for the ISR

    CERN Multimedia

    1975-01-01

    This picture shows mechanical tests of an undulated vacuum chamber for downstream arms of ISR intersections. This chamber, made of 0.3 mm thick inconel, had inner dimensions of 150 mm by 50 mm. The deflection under vacuum is measured by dial gauges. On the left one sees the large vessel where vacuum chambers were tested at pressures above atmospheric pressure.

  20. The LCLS Undulator Beam Loss Monitor Readout System

    Energy Technology Data Exchange (ETDEWEB)

    Dusatko, John; Browne, M.; Fisher, A.S.; Kotturi, D.; Norum, S.; Olsen, J.; /SLAC

    2012-07-23

    The LCLS Undulator Beam Loss Monitor System is required to detect any loss radiation seen by the FEL undulators. The undulator segments consist of permanent magnets which are very sensitive to radiation damage. The operational goal is to keep demagnetization below 0.01% over the life of the LCLS. The BLM system is designed to help achieve this goal by detecting any loss radiation and indicating a fault condition if the radiation level exceeds a certain threshold. Upon reception of this fault signal, the LCLS Machine Protection System takes appropriate action by either halting or rate limiting the beam. The BLM detector consists of a PMT coupled to a Cherenkov radiator located near the upstream end of each undulator segment. There are 33 BLMs in the system, one per segment. The detectors are read out by a dedicated system that is integrated directly into the LCLS MPS. The BLM readout system provides monitoring of radiation levels, computation of integrated doses, detection of radiation excursions beyond set thresholds, fault reporting and control of BLM system functions. This paper describes the design, construction and operational performance of the BLM readout system.

  1. Multiple station beamline at an undulator x-ray source

    DEFF Research Database (Denmark)

    Als-Nielsen, J.; Freund, A.K.; Grübel, G.;

    1994-01-01

    The undulator X-ray source is an ideal source for many applications: the beam is brilliant, highly collimated in all directions, quasi-monochromatic, pulsed and linearly polarized. Such a precious source can feed several independently operated instruments by utilizing a downstream series of X-ray...

  2. Bionic asymmetry: from amiiform fish to undulating robotic fins

    Institute of Scientific and Technical Information of China (English)

    HU TianJiang; SHEN LinCheng; LOW K.H.

    2009-01-01

    Similar to bionic non-smooth which has been successfully applied in anti-resistance and anti-adhesion, bionic asymmetry is also an inherent property of biological systems and is worth exploring for con-ceivable pragmatic applications. Therefore, bionic asymmetry for undulations is of main interest in this paper. We initially investigate bionic asymmetry with a case study of the undulating robotic fin, RoboGnilos, which evolved from the long dorsal fin of Gymnarchus niloticus in the amiiforrn mode. Since the performance of the pre-existing undulating fins is hardly satisfactory, we obtain bionic in-spirations of undulatory asymmetry through observations and measurements on the specimen of G. niloticus, to improve upon the performance. Consequently, the newly acquired innovation for bionic asymmetry is incorporated into the previously derived kinematics model, and also applied to the ex-perimental prototype. Both computational and experimental results verify that bionic asymmetric un-dulation generates better propulsion performance (in terms of linear velocity and efficiency) than the traditional symmetric modes with the same undulatory parameters.

  3. Design of an X-ray FEL undulator

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R. [Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford, California94309 (United States)

    1997-06-01

    An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FEL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. In this paper we use the case of the Linear Coherent Light Source (LCLS) x-ray free electron laser to illustrate design concepts for long free electron laser undulators. The LCLS is intended to create 1.5 {Angstrom} x-rays using an electron beam with 15 GeV energy, 1.5{pi} mm-mrad normalized emittance, 3400 A peak current, and 280 fsec FWHM bunch duration. According to our simulations, this 2{sigma}{sub r}=65mmrms diameter beam must overlap its radiation with a walkoff of no more than 5 {mu}m RMS per 11.7 meter field gain length for efficient gain. The energy spread of the beam is {sigma}{sub E}=0.0002E{sub e}. This places severe limitations on the magnetic field errors and on mechanical tolerances. In this paper we shall discuss how to meet these requirements. {copyright} {ital 1997 American Institute of Physics.}

  4. Design of an X-ray FEL undulator

    International Nuclear Information System (INIS)

    An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FEL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. In this paper we use the case of the Linear Coherent Light Source (LCLS) x-ray free electron laser to illustrate design concepts for long free electron laser undulators. The LCLS is intended to create 1.5 A x-rays using an electron beam with 15 GeV energy, 1.5π mm-mrad normalized emittance, 3400 A peak current, and 280 fsec FWHM bunch duration. According to our simulations, this 2σr=65 mm rms diameter beam must overlap its radiation with a walkoff of no more than 5 μm RMS per 11.7 meter field gain length for efficient gain. The energy spread of the beam is σE=0.0002 Ee. This places severe limitations on the magnetic field errors and on mechanical tolerances. In this paper we shall discuss how to meet these requirements

  5. Undulator physics and coherent harmonic generation at the MAX-lab electron storage ring

    International Nuclear Information System (INIS)

    This work presents the undulator and harmonic generation project at the electron storage ring MAX-lab at University of Lund. The theory of undulator radiation, laser coherent harmonic generation, optical klystron amplifiers and FELs is treated in one uniform way, with complete solutions of the necessary equations. The permanent magnet undulator is described in some detail, along with the installation of the undulator in the storage ring. Details regarding the emitted radiation, the electron beam path in the undulator and other results are analysed. Finally harmonic generation using a Nd:YAG laser and the creation of coherent photons at the third harmonic (355 nm) is described. (author)

  6. Improvements of the undulator spectral performance by compensating the backing beam deflection

    CERN Document Server

    Wang, C; Chang, L H; Chang, C H; Fan, T C; Bach, H; Blomqvist, I

    2002-01-01

    This study thoroughly examines how the backing beam deflection affects the undulator spectral performance. Reduction of the undulator spectral intensity owing to backing beam deflection is analytically evaluated based on plane-wave approximation. The results reveal that the amplitude and the slope of the backing beam deflection affect the undulator spectral performance. Provided is a novel figure-of-merit, rms of the regressed accumulated gap deviation, to determine the backing beam deflection budget. An example of a 3.9 m undulator supporting carriage mounted with 50-mm period length undulator magnet (U5) under a maximum magnetic loading of 5 metric tons at a minimum operating gap of 14 mm, is provided. Its mechanical features are first examined via 3D commercial finite element code ANSYS that concludes the backing beam deflection is influenced heavily by the rigidity of the undulator support frames. Examining the corresponding spectral performance shows that significantly diminishing the undulator spectral ...

  7. High-gain X-ray free electron laser by beat-wave terahertz undulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chao; Hei, DongWei [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an City 710024 (China); Institute of Energy, Tsinghua University, Beijing 100084 (China); Pellegrin, Claudio; Tantawi, Sami [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States)

    2013-12-15

    The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.

  8. Coastline undulations on the West Coast of Denmark: Offshore extent, relation to breaker bars and transported sediment volume

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen; Knudsen, Søren B.

    2012-01-01

    undulations, the amount of sediment transported alongshore in the shoreline undulations, the relationship between the shoreline undulations and longshore bars and the relationship between the morphology and the hydrodynamics. In one of the data sets the shoreline undulations are well correlated...

  9. The U5.0 Undulator for the ALS

    International Nuclear Information System (INIS)

    The U5.0 Undulator, an 89 period, 5 cm period length, 4.6 m long insertion device has been designed and is in fabrication. This undulator will be the first high brightness source, in the 50 to 1500 eV range, for the Advanced Light Source (ALS) and is scheduled for completion in 1992. A modular hybrid configuration utilizing Nd-Fe-B permanent magnet material and vanadium permendur is used that achieves 0.837 Tesla effective peak field. Correction of the vertical field integral is with permanent magnet rotors at the ends. Gap adjustment is with an arrangement of roller screws, chains drives, a gear reduction unit and a stepper motor driven by a closed loop control system. The vacuum chamber design is a two-piece, machined and welded 5083-H321 aluminum construction of 5.1 m length. Magnetic design, subsystem design and fabrication progress are presented. 12 refs., 4 figs., 2 tabs

  10. Rapid and sensitive XAFS using tunable X-ray undulator

    International Nuclear Information System (INIS)

    Novel experimental techniques for rapid and sensitive X-ray absorption fine structure (XAFS) using a tunable X-ray undulator are described. It is shown that a wide energy range (5-25 keV) can be covered by varying the deflection parameter K using the first and third order radiation. Optimizing the band width of undulator by controling the tapered magnet arrays, the rapid measurement of extended X-ray absorption fine structure (EXAFS) in a fluorescence mode is feasible by quick scanning of either a double-crystal monochromator or a mask across the polychromatic beam in an energy-dispersive geometry. Feasibility for both cases is examined and arrangements of optical components are described. (author)

  11. Crystal Undulator As A Novel Compact Source Of Radiation

    CERN Document Server

    Bellucci, S; Biryukov, V M; Britvich, G I; Chesnokov, Yu A; Giannini, G; Guidi, V; Ivanov, Y M; Kotov, V I; Maisheev, V A; Malagu, C; Martinelli, G; Petrunin, A A; Pikalov, V A; Skorobogatov, V V; Stefancich, M; Tombolini, F; Vincenzi, D; Chesnokov, Yu. A.; Ivanov, Yu. M.

    2004-01-01

    A crystalline undulator (CU) with periodically deformed crystallographic planes is capable of deflecting charged particles with the same strength as an equivalent magnetic field of 1000 T and could provide quite a short period L in the sub-millimeter range. We present an idea for creation of a CU and report its first realization. One face of a silicon crystal was given periodic micro-scratches (grooves), with a period of 1 mm, by means of a diamond blade. The X-ray tests of the crystal deformation have shown that a sinusoidal-like shape of crystalline planes goes through the bulk of the crystal. This opens up the possibility for experiments with high-energy particles channeled in CU, a novel compact source of radiation. The first experiment on photon emission in CU has been started at LNF with 800 MeV positrons aiming to produce 50 keV undulator photons.

  12. Reduction of Dynamic Field Errors in Superconductive Undulators

    CERN Document Server

    Peiffer, Peter; Burkart, Florian; Ehlers, Sandra; Keilmann, Alexander; Baumbach, Tilo; Rossmanith, Robert; Schoerling, Daniel

    2010-01-01

    The magnetic field in superconductive undulators is changed by varying the current in the superconductive wires. During operation at stable current, the electric current is confined to the resistance-free filaments. During ramping, however, the superconducting wire bundles have an inductive impedance, causing part of the current to penetrate into the iron body if electric insulation leaks between the wire and the iron body are present. If this is the case the leak currents and other eddy currents decay slowly after the ramp. The magnetic field of the undulator changes during this period. It was shown experimentally that an effective electric insulation between the wires and the iron body can minimize the current and the magnetic field drifts. In this paper the results of these experiments and simulations of the described effects are presented

  13. Design and performance of the APPLE-Knot undulator

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Fuhao [Department of Physics, State Key Laboratory of Surface Physics, and Laboratory of Advanced Materials, Fudan University, 2005 Songhu Road, Shanghai 200438, People’s Republic of (China); Chang, Rui [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, People’s Republic of (China); Zhou, Qiaogen; Zhang, Wei [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai 201204, People’s Republic of (China); Ye, Mao [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, People’s Republic of (China); Sasaki, Shigemi [Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Hiroshima 739-0046 (Japan); Qiao, Shan, E-mail: qiaoshan@mail.sim.ac.cn [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, People’s Republic of (China); School of Physical Science and Technology, ShanghaiTech University, 319 Yueyang Road, Shanghai 200031, People’s Republic of (China)

    2015-06-09

    The design and performance of the Apple-Knot undulator which can generate photons with arbitrary polarization and low on-axis heat load are presented. Along with the development of accelerator technology, synchrotron emittance has continuously decreased. This results in increased brightness, but also causes a heavy heat load on beamline optics. Recently, optical surfaces with 0.1 nm micro-roughness and 0.05 µrad slope error (r.m.s.) have become commercially available and surface distortions due to heat load have become a key factor in determining beamline performance, and heat load has become a serious problem at modern synchrotron radiation facilities. Here, APPLE-Knot undulators which can generate photons with arbitrary polarization, with low on-axis heat load, are reported.

  14. Construction of CHESS compact undulator magnets at Kyma

    Science.gov (United States)

    Temnykh, Alexander B.; Lyndaker, Aaron; Kokole, Mirko; Milharcic, Tadej; Pockar, Jure; Geometrante, Raffaella

    2015-05-01

    In 2014 KYMA S.r.l. has built two CHESS Compact Undulator (CCU) magnets that are at present installed and successfully operate at the Cornell Electron Storage Ring. This type of undulator was developed for upgrade of Cornell High Energy Synchrotron Source beam-lines, but it can be used elsewhere as well. CCU magnets are compact, lightweight, cost efficient and in-vacuum compatible. They are linearly polarized undulators and have a fixed gap. Magnetic field tuning is achieved by phasing (shifting) top magnetic array relative bottom. Two CCUs constructed by KYMA S.r.l. have 28.4 mm period, 6.5 mm gap, 0.93 T peak field. Magnetic structure is of PPM type, made with NdFeB (40UH grade) permanent magnet material. Transitioning from the laboratory to industrial environment for a novel design required additional evaluation, design adjusting and extensive testing. Particular attention was given to the soldering technique used for fastening of the magnetic blocks to holders. This technique had thus far never been used before for undulator magnet construction by industry. The evaluation included tests of different types of soldering paste, measurements of strength of solder and determining the deformations of the soldered magnet and holder under simulated loading forces. This paper focuses on critical features of the CCU design, results of the soldering technique testing and the data regarding permanent magnets magnetization change due to soldering. In addition it deals with optimization-assisted assembly and the performance of the assembled devices and assesses some of the results of the CCU magnets operation at CESR.

  15. Force-Depending Radiation Reaction study in an undulator devise

    CERN Document Server

    López, Gustavo V

    2016-01-01

    The effect of force-depending radiation reaction on charge motion traveling inside an undulator is studied using the new force approach for radiation reaction. The effect on the dynamics of a charged particle is determined with the hope that this one can be measured experimentally and can be determined whether or not this approach points on the right direction to understand the nature of radiation reaction.

  16. Investigation of a 2-Colour Undulator FEL Using Puffin

    CERN Document Server

    Campbell, L T; Reiche, S

    2013-01-01

    Initial studies of a 2-colour FEL amplifier using one monoenergetic electron beam are presented. The interaction is modelled using the unaveraged, broadband FEL code Puffin. A series of undulator modules are tuned to generate two resonant frequencies along the FEL interaction and a self-consistent 2-colour FEL interaction at widely spaced non-harmonic wavelengths at 1nm and 2.4nm is demonstrated.

  17. Elliptically polarizing undulator beamlines at the Advanced Light Source

    International Nuclear Information System (INIS)

    Circular polarization insertion devices and beamlines at the Advanced Light Source are described. The facility will consist of multiple undulators feeding two independent beamlines, one optimized for microscopy and the other for spectroscopy. The energy range of the beamlines will go from below 100 eV to 1,800 eV, enabling studies of the magnetically important L2,3 edges of transition metals and the M4,5 edges of rare earths

  18. Elliptically polarizing undulator beamlines at the Advanced Light Source

    International Nuclear Information System (INIS)

    Circular polarization insertion devices and beamlines at the Advanced Light Source are described. The facility will consist of multiple undulators feeding two independent beamlines, one optimized for microscopy and the other for spectroscopy. The energy range of the beamlines will go from below 100 eV to 1800 eV, enabling studies of the magnetically important L2,3 edges of transition metals and the M4,5 edges of rare earths. copyright 1996 American Institute of Physics

  19. Image Charge Undulator: Theoretical Model and Technical Issues

    International Nuclear Information System (INIS)

    A new device, an image charge undulator, has been proposed recently [1] to utilize this mechanism for generating coherent hard radiation. We demonstrate physics principle of this device by a 2D model of a uniform sheet beam. The transverse image charge wakefields, synchrotron radiation FR-equency and coherent radiation gain length are presented. We discuss a proof-of-principle experiment that takes into consideration such technical issues as grating fabrication, flat beams and beam alignment

  20. Crossed undulator system for a variable polarization synchrotron radiation source

    International Nuclear Information System (INIS)

    A crossed undulator system can produce synchrotron radiation whose polarization is arbitrary and adjustable. The polarization can be linear and modulated between two mutually perpendicular directions, or it can be circular and can be modulated between right and left circular polarizations. The system works on low emittance electron storage rings and can cover a wide spectral range. Topics discussed include the basic principle of the system, the design equations and the limitations in performance

  1. Modulated electron bunch with amplitude front tilt in an undulator

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-12-15

    In a previous paper we discussed the physics of a microbunched electron beam kicked by the dipole field of a corrector magnet by describing the kinematics of coherent undulator radiation after the kick. We demonstrated that the effect of aberration of light supplies the basis for understanding phenomena like the deflection of coherent undulator radiation by a dipole magnet. We illustrated this fact by examining the operation of an XFEL under the steady state assumption, that is a harmonic time dependence. We argued that in this particular case the microbunch front tilt has no objective meaning; in other words, there is no experiment that can discriminate whether an electron beam is endowed with a microbunch front tilt of not. In this paper we extend our considerations to time-dependent phenomena related with a finite electron bunch duration, or SASE mode of operation. We focus our attention on the spatiotemporal distortions of an X-ray pulse. Spatiotemporal coupling arises naturally in coherent undulator radiation behind the kick, because the deflection process involves the introduction of a tilt of the bunch profile. This tilt of the bunch profile leads to radiation pulse front tilt, which is equivalent to angular dispersion of the output radiation. We remark that our exact results can potentially be useful to developers of new generation XFEL codes for cross-checking their results.

  2. Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics

    CERN Document Server

    Jeff, A; Welsch, CP

    2013-01-01

    The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMA...

  3. Wave scattering by a permeable barrier over undulating bed topography

    Science.gov (United States)

    Choudhary, A.; Martha, S. C.

    2016-06-01

    The scattering of surface water waves by bottom undulation in the presence of a permeable vertical barrier is investigated for its solution. A mixed boundary value problem (BVP) arises here in a natural way while examining this physical problem. Regular perturbation analysis is employed to determine the solution of the BVP. By utilizing this analysis the given BVP reduces to two different BVPs up to first order. The solution of the zeroth order BVP is obtained with the aid of eigenfunction expansion method in conjunction with least-squares approximation. The first order BVP is solved with the help of the Green's integral theorem and the physical quantities, namely the reflection and transmission coefficients, are obtained in the form of integrals which involve the bottom undulation and the solution of the zeroth order BVP. A particular form of the bottom undulation which closely resembles to some obstacles made by nature due to sedimentation and ripple growth of sand, is considered to evaluate these integrals. The variation of these coefficients is examined for different values of the porous effect parameter, barrier length, number of ripples and ripple amplitude.

  4. Antiaging activity of low molecular weight peptide from Paphia undulate

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; CAI Bingna; CHEN Hua; PAN Jianyu; CHEN Deke; SUN Huili

    2013-01-01

    Low molecular weight peptide (LMWP) was prepared from clam Paphia undulate and its antiaging effect on D-galactose-induced acute aging in rats,aged Kunming mice,ultraviolet-exposed rats,and thermally injured rats was investigated.P.undulate flesh was homogenized and digested using papain under optimal conditions,then subjected to Sephadex G-25 chromatography to isolate the LMWP.Administration of LMWP significantly reversed D-galactose-induced oxidative stress by increasing the activities ofglutathione peroxidase (GPx) and catalase (CAT),and by decreasing the level ofmalondialdehyde (MDA).This process was accompanied by increased collagen synthesis.The LMWP prevented photoaging and promoted dermis recovery and remission of elastic fiber hyperplasia.Furthermore,treatment with the LMWP helped to regenerate elastic fibers and the collagen network,increased superoxide dismutase (SOD)in the serum and significantly decreased MDA.Thermal scald-induced inflammation and edema were also relieved by the LWMP,while wound healing in skin was promoted.These results suggest that the LMWP from P.undulate could serve as a new antiaging substance in cosmetics.

  5. Antiaging activity of low molecular weight peptide from Paphia undulate

    Science.gov (United States)

    Chen, Xin; Cai, Bingna; Chen, Hua; Pan, Jianyu; Chen, Deke; Sun, Huili

    2013-05-01

    Low molecular weight peptide (LMWP) was prepared from clam Paphia undulate and its antiaging effect on D-galactose-induced acute aging in rats, aged Kunming mice, ultraviolet-exposed rats, and thermally injured rats was investigated. P. undulate flesh was homogenized and digested using papain under optimal conditions, then subjected to Sephadex G-25 chromatography to isolate the LMWP. Administration of LMWP significantly reversed D-galactose-induced oxidative stress by increasing the activities of glutathione peroxidase (GPx) and catalase (CAT), and by decreasing the level of malondialdehyde (MDA). This process was accompanied by increased collagen synthesis. The LMWP prevented photoaging and promoted dermis recovery and remission of elastic fiber hyperplasia. Furthermore, treatment with the LMWP helped to regenerate elastic fibers and the collagen network, increased superoxide dismutase (SOD) in the serum and significantly decreased MDA. Thermal scald-induced inflammation and edema were also relieved by the LWMP, while wound healing in skin was promoted. These results suggest that the LMWP from P. undulate could serve as a new antiaging substance in cosmetics.

  6. Magnetic Properties of Undulator Vacuum Chamber Materials for the Linac Coherent Light Source

    CERN Document Server

    Lee, S H; Vasserman, I; Walters, D R

    2005-01-01

    A prototype vacuum chamber is being designed for use in the Linac Coherent Light Source at Stanford Linear Accelerator Center under development at the Advanced Photon Source. The chamber will be fabricated from the austenite stainless steels. In general, the magnetic properties of austenite stainless steels are affected by their compositions, processing methods and physical conditions. Austenite stainless steels are generally regarded as non-magnetic in the annealed condition and not attracted significantly by a magnet. However, cold working or welding will change their magnetic properties. This paper presents measurements use to choose a proper chamber material for LCLS undulator, to examine the fabrication processes, and to investigate the relative magnetic permeabilities of the stainless steels such as 316LN, 20Cb-3, Nitronic 33, Nitronic 40 and 310S. This paper presents the results of fabricating of 3"-long vacuum chambers along with their permeability measurements. In addition, the magnetic field variati...

  7. IN VACUUM UNDULATOR TASK FORCE REPORT

    Energy Technology Data Exchange (ETDEWEB)

    HASTINGS,J.B.; KAO,C.C.; STEFAN,P.; BURLEY,S.; CARGILL,G.S.; CHANCE,M.; DIERKER,S.; HENDRICKSON,W.; EVANS-LUDERODT,K.; MAO,H.K.

    1998-06-01

    The Green-Chasman lattice, which is the basis for both NSLS storage rings, was conceived with insertion devices in mind. Long, field-free straight sections were provided in the design. The electron optics were chosen so that these sections had zero dispersion and the effects of new magnetic structures placed in these regions would have minimal effect on the emittance of the electron beam. This design concept has been followed by all high-brightness rings which were built subsequent to the NSLS. The X-Ray Ring straight sections also have a very small vertical {beta} function, in addition to the zero dispersion. This was done to optimize the brightness of wiggler sources. There is a further benefit however. The {beta} function determines the beam size and divergence at a particular point in the storage ring lattice. The size is proportional to {radical}{beta} and the divergence is proportional to 1/{radical}{beta}. Thus the electron beam is very small at the center of the X-Ray Ring straight sections. In the initial development of the insertion device program, no specific advantage was taken of this feature. Of the eight straight sections in the X-Ray Ring lattice, five are readily available for magnetic insertion devices and the remaining three are dedicated to radio-frequency drive cavities (2) and injection (1).

  8. In vacuum undulator task force report

    International Nuclear Information System (INIS)

    The Green-Chasman lattice, which is the basis for both NSLS storage rings, was conceived with insertion devices in mind. Long, field-free straight sections were provided in the design. The electron optics were chosen so that these sections had zero dispersion and the effects of new magnetic structures placed in these regions would have minimal effect on the emittance of the electron beam. This design concept has been followed by all high-brightness rings which were built subsequent to the NSLS. The X-Ray Ring straight sections also have a very small vertical β function, in addition to the zero dispersion. This was done to optimize the brightness of wiggler sources. There is a further benefit however. The β function determines the beam size and divergence at a particular point in the storage ring lattice. The size is proportional to √β and the divergence is proportional to 1/√β. Thus the electron beam is very small at the center of the X-Ray Ring straight sections. In the initial development of the insertion device program, no specific advantage was taken of this feature. Of the eight straight sections in the X-Ray Ring lattice, five are readily available for magnetic insertion devices and the remaining three are dedicated to radio-frequency drive cavities (2) and injection (1)

  9. Numerical investigation of the radiation characteristics of a variable-period helical undulator

    Science.gov (United States)

    Lee, Kitae; Mun, Jungho; Hee Park, Seong; Jang, Kyu-Ha; Uk Jeong, Young; Vinokurov, Nikolay A.

    2015-03-01

    A helical undulator with a variable-period capability has been developed at the Korea Atomic Energy Research Institute (KAERI) to generate high power radiation in the terahertz range. A simulation code for the spontaneous emission from an electron beam inside an undulator has been developed to characterize the performance of the undulator. In the case of the KAERI undulator, there is a non-negligible high-order harmonics in the longitudinal field distribution compared with a bifilar one.The axial velocity modulation by the high-order harmonics in the field distribution has been found to lead to small deviation of the spectrum of spontaneous emission from the KAERI undulator with respect to the bifilars one. The gain functions obtained from the spontaneous emission spectra according to the Madey theory, show similar shapes for both undulators.

  10. Computational and experimental study on dynamic behavior of underwater robots propelled by bionic undulating fins

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Bionic undulating fins, inspired by undulations of the median and/or paired fin (MPF) fish, have a bright prospective for un-derwater missions with higher maneuverability, lower noisy, and higher efficiency. In the present study, a coupled computa-tional fluid dynamics (CFD) model was proposed and implemented to facilitate numerical simulations on hydrodynamic ef-fects of the bionic undulating robots. Hydrodynamic behaviors of underwater robots propelled by two bionic undulating fins were computationally and experimentally studied within the three typical desired movement patterns, i.e., marching, yawing and yawing-while-marching. Moreover, several specific phenomena in the bionic undulation mode were unveiled and dis-cussed by comparison between the CFD and experimental results under the same kinematics parameter sets. The contributed work on the dynamic behavior of the undulating robots is of importance for study on the propulsion mechanism and control algorithms.

  11. A comparison of satellite Doppler and gravimetric geoid undulations considering terrain-corrected gravity data

    Science.gov (United States)

    Rapp, R. H.; Wichiencharoen, C.

    1984-01-01

    Geoid undulations derived from Doppler satellite positioning are compared with corresponding values derived from terrestrial and satellite information using three different procedures. Doppler undulations are compared with uncorrected gravimetric undulations, and systematic differences of 1.6 m and 0.4 m are found for western and eastern U.S. stations, respectively. The systematic difference of 1.6 m was reduced to 0.1 m when terrain-related corrections were applied. Undulations computed from a spherical harmonic expansion to degree 180 yielded standard deviations only slightly poorer than the combined data. A more systematic difference in the western than in the eastern stations remained.

  12. Laser-driven soft-X-ray undulator source

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Matthias

    2010-08-04

    The experimental results described in this thesis demonstrate the successful synergy between the research fields described above: the development of an undulator source driven by laser-plasma accelerated electron beams. First efforts in this new field have led to the production of radiation in the visible to infrared part of the electromagnetic spectrum [Schlenvoigt et al., 2008]. In contrast to these early achievements, the experiment described here shows the successful production of laser-driven undulator radiation in the soft-X-ray range with a remarkable reproducibility. The source produced tunable, collimated beams with a wavelength of {proportional_to}17 nm from a compact setup. Undulator spectra were detected in {proportional_to}70% of consecutive driver-laser shots, which is a remarkable reproducibility for a first proof-of-concept demonstration using ultra-high intensity laser systems. This can be attributed to a stable electron acceleration scheme as well as to the first application of miniature magnetic quadrupole lenses with laseraccelerated beams. The lenses significantly reduce the electron beam divergence and its angular shot-to-shot fluctuations The setup of this experiment is the foundation of potential university-laboratory-sized, highly-brilliant hard X-ray sources. By increasing the electron energy to about 1 GeV, X-ray pulses with an expected duration of {proportional_to}10 fs and a photon energy of 1 keV could be produced in an almost identical arrangement. It can also be used as a testbed for the development of a free-electron laser of significantly smaller dimension than facilities based on conventional accelerators [Gruener et al., 2007]. Such compact sources have the potential for application in many fields of science. In addition, these developments could lead to ideal sources for ultrafast pump-probe experiments due to the perfect synchronization of the X-ray beam to the driver laser. (orig.)

  13. Laser-driven soft-X-ray undulator source

    International Nuclear Information System (INIS)

    The experimental results described in this thesis demonstrate the successful synergy between the research fields described above: the development of an undulator source driven by laser-plasma accelerated electron beams. First efforts in this new field have led to the production of radiation in the visible to infrared part of the electromagnetic spectrum [Schlenvoigt et al., 2008]. In contrast to these early achievements, the experiment described here shows the successful production of laser-driven undulator radiation in the soft-X-ray range with a remarkable reproducibility. The source produced tunable, collimated beams with a wavelength of ∝17 nm from a compact setup. Undulator spectra were detected in ∝70% of consecutive driver-laser shots, which is a remarkable reproducibility for a first proof-of-concept demonstration using ultra-high intensity laser systems. This can be attributed to a stable electron acceleration scheme as well as to the first application of miniature magnetic quadrupole lenses with laseraccelerated beams. The lenses significantly reduce the electron beam divergence and its angular shot-to-shot fluctuations The setup of this experiment is the foundation of potential university-laboratory-sized, highly-brilliant hard X-ray sources. By increasing the electron energy to about 1 GeV, X-ray pulses with an expected duration of ∝10 fs and a photon energy of 1 keV could be produced in an almost identical arrangement. It can also be used as a testbed for the development of a free-electron laser of significantly smaller dimension than facilities based on conventional accelerators [Gruener et al., 2007]. Such compact sources have the potential for application in many fields of science. In addition, these developments could lead to ideal sources for ultrafast pump-probe experiments due to the perfect synchronization of the X-ray beam to the driver laser. (orig.)

  14. Development of a Quasi-Periodic Undulator for the HLS

    CERN Document Server

    Yang, Yufeng; Chen, Wan; Jia, Qika; Sun, Shuchen; Li, Zhiqiang

    2014-01-01

    China's first quasi-periodic undulator (QPU) has been developed for the Hefei Light Source (HLS). It uses a magnetic configuration with varied thicknesses of NdFeB blocks, based on the QPU of European Synchrotron Radiation Facility (ESRF). Depression of 3rd harmonic radiation is significantly improved over the ESRF QPU, as deduced from the measured magnetic fields. A method of configuring shims of different geometries and sizes, based on a symmetric principle to correct multi-pole field integrals, was demonstrated.

  15. Direct Observation of Ultralow Vertical Emittance using a Vertical Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent

    2015-09-17

    In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances [K. P. Wootton, et al., Phys. Rev. ST Accel. Beams, 17, 112802 (2014)]. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed.

  16. Undulating fins produce off-axis thrust and flow structures.

    Science.gov (United States)

    Neveln, Izaak D; Bale, Rahul; Bhalla, Amneet Pal Singh; Curet, Oscar M; Patankar, Neelesh A; MacIver, Malcolm A

    2014-01-15

    While wake structures of many forms of swimming and flying are well characterized, the wake generated by a freely swimming undulating fin has not yet been analyzed. These elongated fins allow fish to achieve enhanced agility exemplified by the forward, backward and vertical swimming capabilities of knifefish, and also have potential applications in the design of more maneuverable underwater vehicles. We present the flow structure of an undulating robotic fin model using particle image velocimetry to measure fluid velocity fields in the wake. We supplement the experimental robotic work with high-fidelity computational fluid dynamics, simulating the hydrodynamics of both a virtual fish, whose fin kinematics and fin plus body morphology are measured from a freely swimming knifefish, and a virtual rendering of our robot. Our results indicate that a series of linked vortex tubes is shed off the long edge of the fin as the undulatory wave travels lengthwise along the fin. A jet at an oblique angle to the fin is associated with the successive vortex tubes, propelling the fish forward. The vortex structure bears similarity to the linked vortex ring structure trailing the oscillating caudal fin of a carangiform swimmer, though the vortex rings are distorted because of the undulatory kinematics of the elongated fin. PMID:24072799

  17. Fracture mechanics parameters for cracks on a slightly undulating interface

    Science.gov (United States)

    Yang, Lin; Qu, Jianmin

    1993-11-01

    Typical bimaterial interfaces are nonplanar due to surface facets or roughness. Crack-tip stress fields of an interface crack must be influenced by nonplanarity of the interface. Consequently, interface toughness is affected. The crack-tip fields of a finite crack on an elastic/rigid interface with periodic undulation are studied. Particular emphasis is given to the fracture mechanics parameters, such as the stress intensity factors, crack-tip energy release rate, and crack-tip mode mixity. When the amplitude of interface undulation is very small relative to the crack length (which is the case for rough interfaces), asymptotic analysis is used to convert the nonplanarity effects into distributed dislocations located on the planar interface. Then, the resulting stress fields near the crack tip are obtained by using the Fourier integral transform method. It is found that the stress fields at the crack tip are strongly influenced by nonplanarity of the interface. Generally speaking, nonplanarity of the interface tends to shield the crack tip by reducing the crack-tip stress concentration.

  18. Ripple reduction control of the undulation pump total artificial heart.

    Science.gov (United States)

    Saito, Itsuro; Chinzei, Tsuneo; Mochizuki, Shuichi; Abe, Yusuke; Isoyama, Takashi; Iwasaki, Kiyotaka; Suzuki, Takafumi; Karita, Tatsuro; Ono, Toshiya; Kouno, Akimasa; Ishimaru, Mitsuhiko; Baba, Atsushi; Ozeki, Toshinaga; Tohyama, Takahiro; Kobayashi Si, Shin-ichi; Imachi, Kou

    2002-01-01

    An undulation pump total artificial heart (UPTAH) in which the revolutions of the motor are converted to undulation motion of a disk has been developed. In an experiment, a goat using the UPTAH survived for 54 days. However, a large ripple was observed in the device's output pressure and flow waveform. In calculating the spectrum of the ripple, we found that the ripple mainly comprised 2 frequency sine waves: 1 having the same frequency as and 1 having double the frequency of the motor revolutions. To reduce the ripple, 2 sine waves, 1 having the same frequency as and 1 having double the frequency of the motor revolutions, were provided to the motor current to modulate the pulse width of the pulse width modulation controlling the motor revolutions. This ripple control method reduced the pressure ripple by 90% in a mock circulation and by 70% in animal experiments. These results revealed that the ripple generated in the UPTAH could be controlled through the use of motor control software.

  19. Direct Observation of Ultralow Vertical Emittance using a Vertical Undulator - presentation slides

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent

    2015-09-17

    Direct emittance measurement based on vertical undulator is discussed. Emittance was evaluated from peak ratios, the smallest measured being =0.9 ±0.3 pm rad. The angular distribution of undulator radiation departs from Gaussian approximations, a fact of which diffraction-limited light sources should be aware.

  20. Status of a cylindrical superconducting undulator for the laser wakefield accelerator in Jena

    Energy Technology Data Exchange (ETDEWEB)

    Afonso Rodriguez, Veronica; Bernhard, Axel; Grau, Andreas; Haerer, Bastian; Peiffer, Peter; Rossmanith, Robert; Weber, Marc; Widmann, Christina [KIT, Karlsruhe (Germany); Kaluza, Malte; Nicolai, Maria; Rinck, Thorsten; Saevert, Alexander [Friedrich Schiller University Jena, Jena (Germany); Jaeckel, Oliver; Reuter, Maria [Helmholtz Institute Jena, Jena (Germany)

    2013-07-01

    Laser-Wakefield accelerators (LWFA) produce electron bunches with several 100 MeV energy within a few millimeters acceleration length, however, with a relatively large energy spread (a few percent). Undulators provide monochromatic radiation with high brilliance. The working principle of undulators requires a small energy spread of the electron beam in the order of 0.1 %. To produce monochromatic undulator radiation with LWF accelerated electrons, a novel iron-free cylindrical superconducting undulator (SCU) is under development at the KIT. This talk gives an overview about the design and the optimisation of the SCU tailored to the particular beam properties of the JETI-LWFA at the University of Jena. In addition a short model test and the construction status of the full scale undulator are shown.

  1. Up-grading a 4.7-cm-period plane electromagnetic undulator

    CERN Document Server

    Bogachenkov, V A; Papadichev, V A

    1999-01-01

    Electromagnetic undulators have a number of advantages over permanent-magnet undulators. They are less expensive to fabricate and their field is easily regulated by changing the current, without requiring a complex and expensive precision system for changing the undulator gap. Their main weaknesses are that they require a large power supply and that the field is limited due to yoke saturation mainly because of large axial stray fluxes, particularly in simple constructions. Modernization of a 4.7-cm-period, 20-period long plane electromagnetic undulator of simple design is described. Samarium-cobalt permanent magnets were used to increase the field and decrease power consumption. They were placed between adjacent rings (with opposite sign of field) and while increasing the working field they decreased saturation of the iron yokes. Small lateral displacements of permanent magnets were used to equalize field amplitudes in half periods of the undulator with 0.1% accuracy. Matched input and output to and from the ...

  2. Interfaces modify the undulation spectrum of bicontinuous microemulsions

    Science.gov (United States)

    Holderer, O.; Lipfert, F.; Frielinghaus, H.; Ohl, M.; Richter, D.

    2015-01-01

    Recently, the structure and dynamics of microemulsions adjacent to a planar hydrophilic wall have been characterized using grazing incidence small angle neutron scattering (GISANS) and grazing incidence neutron spin echo (GINSES) spectroscopy, respectively. It has been found that a bicontinuous microemulsion develops a lamellar structure, and that the relaxation rate is faster for a membrane close to the interface compared to the bulk. A model developed by Seifert was employed to explain the discovered acceleration for the near-surface lamellar ordered membranes. In this contribution we present how confinement of a flat interface influences the elastic properties of surfactant membranes and discuss the effect of locally introduced flat interfaces by clay platelets. This analysis sheds light onto the undulation mode spectrum of the surfactant membrane.

  3. Interfaces modify the undulation spectrum of bicontinuous microemulsions

    Directory of Open Access Journals (Sweden)

    Holderer O.

    2015-01-01

    Full Text Available Recently, the structure and dynamics of microemulsions adjacent to a planar hydrophilic wall have been characterized using grazing incidence small angle neutron scattering (GISANS and grazing incidence neutron spin echo (GINSES spectroscopy, respectively. It has been found that a bicontinuous microemulsion develops a lamellar structure, and that the relaxation rate is faster for a membrane close to the interface compared to the bulk. A model developed by Seifert was employed to explain the discovered acceleration for the near-surface lamellar ordered membranes. In this contribution we present how confinement of a flat interface influences the elastic properties of surfactant membranes and discuss the effect of locally introduced flat interfaces by clay platelets. This analysis sheds light onto the undulation mode spectrum of the surfactant membrane.

  4. Thermal undulations of quasi-spherical vesicles stabilized by gravity

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Ipsen, John Hjorth

    2002-01-01

    The classical treatment of quasi-spherical vesicle undulations has, in the present work, been reviewed and extended to systems, which are affected by a gravitational field caused by a density difference across the membrane. The effects have been studied by the use of perturbation theory leading......) = DeltapgR(4)/k. The contributions from gravity are in most experimental situations small and thus negligible, but for values of go above a certain limit, the perturbational corrections must be included. Expressions for the relative error on the flicker spectrum have been worked out, so that it is possible...... to define the regime where gravity is negligible. An upper limit of go has also been identified, where the error in all modes of the flicker spectrum is significant due to distortion of the mean shape....

  5. Cryogenic performance of a cryocooler-cooled superconducting undulator

    Energy Technology Data Exchange (ETDEWEB)

    Fuerst, J. D.; Doose, C.; Hasse, Q.; Ivanyushenkov, Y.; Kasa, M.; Shiroyanagi, Y. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2014-01-29

    A cryocooler-cooled superconducting undulator has been installed and operated with beam at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The device consists of a dual-core 42-pole magnet structure that is cooled to 4.2 K with a system of four cryocoolers operating in a zero-boil-off configuration. This effort represents the culmination of a development program to establish concept feasibility and evaluate cryostat design and cryocooler-based refrigeration. Cryostat performance is described including cool-down/warm-up, steady-state operation, cooling margin, and the impact of beam during operation in the APS storage ring. Plans for future devices with longer magnets, which will incorporate lessons learned from the development program, are also discussed.

  6. Crystalline undulator radiation and sub-harmonic bifurcation of system

    Institute of Scientific and Technical Information of China (English)

    Luo Xiao-Hua; He Wei; Wu Mu-Ying; Shao Ming-Zhu; Luo Shi-Yu

    2013-01-01

    Looking for new light sources,especially short wavelength laser light sources has attracted widespread attention.This paper analytically describes the radiation of a crystalline undulator field by the sine-squared potential.In the classical mechanics and the dipole approximation,the motion equation of a particle is reduced to a generalized pendulum equation with a damping term and a forcing term.The bifurcation behavior of periodic orbits is analyzed by using the Melnikov method and the numerical method,and the stability of the system is discussed.The results show that,in principle,the stability of the system relates to its parameters,and only by adjusting these parameters appropriately can the occurrence of bifurcation be avoided or suppressed.

  7. Marine Geoid Undulation Assessment Over South China Sea Using Global Geopotential Models and Airborne Gravity Data

    Science.gov (United States)

    Yazid, N. M.; Din, A. H. M.; Omar, K. M.; Som, Z. A. M.; Omar, A. H.; Yahaya, N. A. Z.; Tugi, A.

    2016-09-01

    Global geopotential models (GGMs) are vital in computing global geoid undulations heights. Based on the ellipsoidal height by Global Navigation Satellite System (GNSS) observations, the accurate orthometric height can be calculated by adding precise and accurate geoid undulations model information. However, GGMs also provide data from the satellite gravity missions such as GRACE, GOCE and CHAMP. Thus, this will assist to enhance the global geoid undulations data. A statistical assessment has been made between geoid undulations derived from 4 GGMs and the airborne gravity data provided by Department of Survey and Mapping Malaysia (DSMM). The goal of this study is the selection of the best possible GGM that best matches statistically with the geoid undulations of airborne gravity data under the Marine Geodetic Infrastructures in Malaysian Waters (MAGIC) Project over marine areas in Sabah. The correlation coefficients and the RMS value for the geoid undulations of GGM and airborne gravity data were computed. The correlation coefficients between EGM 2008 and airborne gravity data is 1 while RMS value is 0.1499.In this study, the RMS value of EGM 2008 is the lowest among the others. Regarding to the statistical analysis, it clearly represents that EGM 2008 is the best fit for marine geoid undulations throughout South China Sea.

  8. A Coherent Compton Backscattering High Gain FEL using an X-Band Microwave Undulator

    CERN Document Server

    Pellegrini, C; Travish, G

    2005-01-01

    We describe a proposed high-gain FEL using an X-band microwave undulator and operating at a wavelength of about 0.5 μm. The FEL electron beam energy is 65 MeV. The beam is produced by the NLCTA X-band linac at SLAC, using an S-band high-brightness photoinjector. The undulator consists of a circular waveguide with an rf wave counter-propagating with respect to the electron beam. The undulator is powered with two high-power X-band klystrons and a dual-moded pulse compressor recently developed at SLAC. This system is capable of delivering flat-top rf pulses of up to 400 ns and a few hundred megawatts. The equivalent undulator period is 1.4 cm, the radius of the circular pipe is 1 cm, and the undulator parameter is about 0.4 for a helical undulator configuration, obtained using two cross-polarized TE modes, or larger for a planar configuration, using one rf polarization. The undulator is about four meters long. The FEL will reach saturation within this distance when operated in a SASE mode. We describe t...

  9. Analysis of the 3D magnetic field and its errors for undulators with iron poles

    Energy Technology Data Exchange (ETDEWEB)

    Ingold, G.; Bahrdt, J.; Gaupp, A. [BESSY GmbH, Berlin (Germany)] [and others

    1995-12-31

    The attainable field strength and field quality, such as the optical phase error, the electron beam displacement within the undulator and higher order multipoles of the magnetic field, are discussed. These issues are critical to the design and construction of short period undulators for use in short wavelength FEL or for operation in third generation light sources. We discuss two approaches: (i) For superferric undulators the construction of a full length device would rely on the optimum sorting of precision machined undulator segments. Magnetic data on segments with 20 periods (period length 8.80mm) will be presented. (ii) For hybrid undulators the sorting has to be done on individual poles and magnets. For this approach typical error sources such as machining tolerances, magnetization errors of the permanent magnet material and assembly errors are modeled in 3D and compared to induced errors on an existing hybrid undulator segment. In case of undulators having a full length of hundred periods at least five times as many individual parts have to be characterized. This should be done automatically where both the mechanical and magnetic data before and after the assembly of the magnetic structure are recorded in one step. A CNC programmable measuring device suitable for this task will shortly be presented.

  10. Performance of a hard x-ray undulator at CHESS (invited)

    International Nuclear Information System (INIS)

    A 3.3-cm period Nd-Fe-B hybrid undulator has been designed and successfully operated in the Cornell Electron Storage Ring (CESR). This 2-m-long, 123-pole insertion device is a prototype of one of the undulators planned for the Advanced Photon Source. In dedicated operation, the undulator produced the expected brightness at 5.437 GeV with the fundamental x-ray energy ranging from 4.3 to 7.9 keV corresponding to a change in gap from 1.5 to 2.8 cm

  11. Calculation of undulator radiation from measured magnetic fields and comparison with measured spectra

    International Nuclear Information System (INIS)

    A new code was developed that calculates the spectrum, the state and the degree of polarization of the radiation emitted by any insertion device. It integrates along an arbitrary electron trajectory without any approximations. The trajectory can be derived either from a model undulator including random field errors or from a measured field distribution from a real undulator. The calculated one-electron pattern is convoluted with the electron beam emittance. Spectral calculations for the crossed field undulator U-2 at BESSY employing measured magnetic field data agree with absolute measurements of the spectra. (author) 18 refs.; 1 fig

  12. Spectrum splitting for fast polarization switching of undulator radiation.

    Science.gov (United States)

    Kinjo, Ryota; Tanaka, Takashi

    2016-05-01

    A simple scheme to quickly switch the polarity of circular radiation is proposed, which is based on spectrum splitting of undulator radiation. In this scheme, two helical undulators with opposite helicities are placed tandem in one straight section, both of which are divided into several segments. The optical phases between segments are tuned so that light waves from one of the two undulators are out of phase, while those from the other are in phase. Then the radiation spectrum of the former is split and the intensity at the fundamental photon energy vanishes. As a consequence, the monochromated photon beam at the fundamental energy is circularly polarized with the helicity specified by the in-phase undulator, which can be quickly flipped by tuning the optical phase. Numerical calculations carried out to demonstrate the feasibility of the proposed scheme show that a relatively high degree of circular polarization is expected if the angular acceptance of the beamline is not too large.

  13. Radiation from relativistic electrons in "light" and in conventional undulators. Classical and quantum approaches

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strokov, S. A.

    2016-07-01

    A photon spectrum of undulator radiation (UR) is calculated in the semi-classical approach. The UR intensity spectrum is determined by an electron trajectory in the undulator neglecting by energy losses for radiation. Using the Planck's law, the UR photon spectrum can be calculated from the classical intensity spectrum both for linear and nonlinear regimes. The radiation of an electron in a field of strong electromagnetic wave (radiation in the "light" undulator) is considered in the quantum electromagnetic frame. Comparison of results obtained by both approaches has been shown that UR spectra in the whole cone coincide with high accuracy for the case xbeam were simulated with taking into account the discrete process of photon emission along an electron trajectory in both kinds of undulators.

  14. A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University

    Science.gov (United States)

    Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu

    2010-06-01

    In order to develop an intense far-infrared radiation source, a high quality electron beam has been studied at Tohoku University, Sendai. The bunch length of the beam expected is very much shorter than terahertz (THz) wavelength, so that coherent spontaneous emission of synchrotron radiation will be a promising high brilliant far-infrared source. An undulator consisting of permanent magnets has been designed in which optional free electron laser (FEL) will be operated in free space mode. Consequently the minimum gap of the undulator is decided to be 54 mm for 0.36 mm radiation to avoid diffraction loss, and then the period length of 10 cm is employed. The undulator may cover a wavelength range from 0.18 to 0.36 mm with the beam energy of 17 MeV. Property of coherent THz radiation from the undulator and possibility of novel pre-bunched THz FEL is discussed.

  15. Design of a Precision Positioning System for the Undulators of the Linac Coherent Light Source

    CERN Document Server

    Trakhtenberg, Emil; Den Hartog, Patric; White, Marion

    2005-01-01

    A precision positioning system has been designed for the Linac Coherent Light Source (LCLS) and a prototype system is being fabricated. The LCLS will use a beam based alignment technique to precisely align all of the segments of the 130-m long undulator line. The requirement for overlap between the electron beam and the x-ray beam, in order to develop and maintain lasing, demands that each of the quadrupoles be aligned within a tolerance of ± 2 μm and that the undulator axis be positioned within ± 10 μm vertically and horizontally. Five cam movers, each with an eccentricity of 1.5 mm, will allow adjustment of a cradle supporting the undulator, its vacuum chamber, a quadrupole, and a beam position monitor. An additional motion transverse to the beam axis allows removal of individual undulators from the beam path. Positioning feedback will be provided by a wire position monitor system and a hydrostatic leveling system.

  16. Start-to-end global imaging as a sunward propagating, SAPS-associated giant undulation event

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Michael G [Los Alamos National Laboratory; Donovan, Eric F [U OF CALGARY; Foster, John C [MIT; Mann, Ian R [UNIV OF ALBERTA; Immel, Thomas J [UC/BERKELEY; Mende, Stephen B [UN/BERKELEY; Sigwarth, John B [NASA/GSFC

    2009-01-01

    We present high-time resolution global imaging of a sunward propagating giant undulation event from start to finish. The event occurred on November 24, 2001 during a very disturbed storm interval. The giant undulations began to develop at around 13UT and persisted for approximately 2 hours. The sunward propagation speed was on the order of 0.6 km/s (relative to SM coordinate system). The undulations had a wavelength of {approx} 750 km, amplitudes of {approx} 890 km and produced ULF pulsations on the ground with a period of {approx} 1108s. We show that the undulations were associated with SAPs flows that were caused by the proton plasma sheet penetrating substantially farther Earthward than the electron plasma sheet on the duskside. The observations appear to be consistent with the development of a shear flow and/or ballooning type of instability at the plasmapause driven by intense SAPS-associated shear flows.

  17. A review of undulated sediment features on Mediterranean prodeltas: distinguishing sediment transport structures from sediment deformation

    OpenAIRE

    Urgeles, Roger; Cattaneo, Antonio; PUIG Pere; Liquete, Camino; Mol, Ben; Amblas, David; Sultan, Nabil; Trincardi, Fabio

    2011-01-01

    Most Mediterranean prodeltas show undulated sediment features on the foresets of their Holocene wedges. These features have been described all along the Mediterranean for the last 30 years and interpreted as either soft sediment deformation and incipient landsliding, and more recently, as sediment transport structures. We perform a review and detailed analysis of these undulated sediment features using ultrahigh-resolution seismic and bathymetric data as well as geotechnical information and h...

  18. Brightness and coherence of radiation from undulators and high-gain free electron lasers

    International Nuclear Information System (INIS)

    The purpose of this paper is to review the radiation characteristics of undulators and high-gain free electron lasers (FELs). The topics covered are: a phase-space method in wave optics and synchrotron radiation, coherence from the phase-space point of view, discussions of undulator performances in next-generation synchrotron radiation facility and the characteristics of the high-gain FELs and their performances

  19. Empirical Optimization of Undulator Tapering at FLASH2 and Comparison with Numerical Simulations

    CERN Document Server

    Mak, Alan; Faatz, Bart; Werin, Sverker

    2016-01-01

    In a free-electron laser equipped with variable-gap undulator modules, the technique of undulator tapering opens up the possibility to increase the radiation power beyond the initial saturation point, thus enhancing the efficiency of the laser. The effectiveness of the enhancement relies on the proper optimization of the taper profile. In this work, a multidimensional optimization approach is implemented empirically in the x-ray free-electron laser FLASH2. The empirical results are compared with numerical simulations.

  20. Investigation of the polarization state of dual APPLE-II undulators

    Energy Technology Data Exchange (ETDEWEB)

    Hand, Matthew; Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Dhesi, Sarnjeet S.; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom)

    2016-01-01

    Complete polarization analysis of the photon beam produced by a dual APPLE-II undulator configuration using a multilayer-based soft X-ray polarimeter is given. The use of an APPLE II undulator is extremely important for providing a high-brilliance X-ray beam with the capability to switch between various photon beam polarization states. A high-precision soft X-ray polarimeter has been used to systematically investigate the polarization characteristics of the two helical APPLE II undulators installed on beamline I06 at Diamond Light Source. A simple data acquisition and processing procedure has been developed to determine the Stokes polarization parameters for light polarized at arbitrary linear angles emitted from a single undulator, and for circularly polarized light emitted from both undulators in conjunction with a single-period undulator phasing unit. The purity of linear polarization is found to deteriorate as the polarization angle moves away from the horizontal and vertical modes. Importantly, a negative correlation between the degree of circular polarization and the photon flux has been found when the phasing unit is used.

  1. Optimizing an undulating magnetic microswimmer for cargo towing

    Science.gov (United States)

    Or, Yizhar; Gutman, Emiliya

    2015-11-01

    One of the promising applications of robotic microswimmers is towing a cargo for controlled drug delivery, micro-surgery or tumor detection. This capability has been demonstrated by the magnetically-actuated microswimmer of Dreyfus et al. [Nature 2005] in which a red blood cell was attached to a chain of magnetic beads connected by flexible DNA links. A key question is what should be the optimal size of the magnetic tail for towing a given cargo. This question is addressed here for the simplest theoretical model of a magnetic microswimmer under planar undulations - a spherical load connected by a torsion spring to a magnetized rigid slender link. The swimmer's dynamics is formulated assuming negligible hydrodynamic interaction and leading-order expressions for the resulting motion are obtained explicitly under small amplitude approximation. Optimal combinations of magnetic actuation frequency, torsion stiffness, and tail length for maximizing displacement or average speed are obtained. The theoretical results are compared with several reported magnetic microswimmers, and also agree qualitatively with recent results on cargo towing by screw rotation of magnetic helical tails [Walker et al., ACS Nano Letters 2015]. This work is supported by the Israeli Science Foundation (ISF) under Grant No. 567/14.

  2. Patterns in biofilms: From contour undulations to fold focussing

    Science.gov (United States)

    Ben Amar, Martine; Wu, Min

    2014-11-01

    Morphologies of soft materials in growth, swelling or drying have been extensively studied recently. Shape modifications occur as the size varies transforming ordinary spheres, cylinders and thin plates into more or less complex objects. Here we consider the genesis of biofilm patterns when a simple disc containing initially bacteria with moderate adhesion to a rigid substrate grows according to very simple rules. The initial circular geometry is lost during the growth expansion, contour undulations and buckling appear, ultimately a rather regular periodic focussing of folds repartition emerges. We theoretically predict these morphological instabilities as bifurcations of solutions in elasticity, characterized by typical driving parameters established here. The substrate plays a critical role limiting the geometry of the possible modes of instabilities and anisotropic growth, adhesion and toughness compete to eventually give rise to wrinkling, buckling or both. Additionally, due to the substrate, we show that the ordinary buckling modes, vertical deviation of thin films, are not observed in practice and a competitive pattern with self-focussing of folds can be found analytically. These patterns are reminiscent of the blisters of delamination in material sciences and explain recent observations of bacteria biofilms. The model presented here is purely analytical, is based on a neo-Hookean elastic energy, and can be extended without difficulties and applied to polymer materials.

  3. Beam Diagnostics for Laser Undulator Based on Compton Backward Scattering

    CERN Document Server

    Kuroda, R

    2005-01-01

    A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on Compton backward scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser (10ps FWHM) and about 5 MeV high quality electron beam (10ps FWHM) generated from rf gun system. The range of X-ray energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein's coefficient in this range, a dehydration of the specimens is not necessary. To generate the soft X-ray pulse stably, the electron beam diagnostics have been developed such as the emittance measurement using double slit scan technique, the bunch length measurement using two frequency analysis technique. In this confere...

  4. Geometric Mechanics Reveals Optimal Complex Terrestrial Undulation Patterns

    Science.gov (United States)

    Gong, Chaohui; Astley, Henry; Schiebel, Perrin; Dai, Jin; Travers, Matthew; Goldman, Daniel; Choset, Howie; CMU Team; GT Team

    Geometric mechanics offers useful tools for intuitively analyzing biological and robotic locomotion. However, utility of these tools were previously restricted to systems that have only two internal degrees of freedom and in uniform media. We show kinematics of complex locomotors that make intermittent contacts with substrates can be approximated as a linear combination of two shape bases, and can be represented using two variables. Therefore, the tools of geometric mechanics can be used to analyze motions of locomotors with many degrees of freedom. To demonstrate the proposed technique, we present studies on two different types of snake gaits which utilize combinations of waves in the horizontal and vertical planes: sidewinding (in the sidewinder rattlesnake C. cerastes) and lateral undulation (in the desert specialist snake C. occipitalis). C. cerastes moves by generating posteriorly traveling body waves in the horizontal and vertical directions, with a relative phase offset equal to +/-π/2 while C. occipitalismaintains a π/2 offset of a frequency doubled vertical wave. Geometric analysis reveals these coordination patterns enable optimal movement in the two different styles of undulatory terrestrial locomotion. More broadly, these examples demonstrate the utility of geometric mechanics in analyzing realistic biological and robotic locomotion.

  5. Measurement of position and profile of undulator radiation in Indus-2 using scanning wire monitor

    International Nuclear Information System (INIS)

    Two planar undulators (U1 and U2) for Atomic Molecular Spectroscopy (AMOS) beamline and Angle Resolved Photoelectron Spectroscopy (ARPES) beamline have been installed in Indus-2. The U1 undulator is designed to produce photons in the energy range of 6 eV to 250 eV and U2 undulator is designed to produce photons in the energy range of 30 eV to 600 eV. In order to measure the position and vertical profile of photon beams emitted from these undulators, one scanning wire monitor has been installed in each beamline front end. In these scanning wire monitors, a gold coated tungsten wire of 100 μm thickness, stretched between a fork shaped alumina ceramic holder, is scanned vertically perpendicular to the direction of propagation of photon beam by using a precisely controlled stepper motor. The photo-electron current generated in the wire is measured by an electrometer. A graphical user interface has been developed which facilitates the scanning as per the given range, plots the graphs and stores the scanned data in Excel file. This paper describes our experience and usefulness of these wire monitors during commissioning of planar undulators in Indus-2. (author)

  6. Undulator beamline of the Brockhouse sector at the Canadian Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, B., E-mail: beatriz.moreno@lightsource.ca, E-mail: skycia@uoguelph.ca; Gomez, A.; Duffy, A.; Hallin, E. [Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3 (Canada); Meyer, B. [Brazilian Synchrotron, 11000 Giuseppe Maximo Scolfaro, Campinas, SP 13085-903 (Brazil); Kycia, S., E-mail: beatriz.moreno@lightsource.ca, E-mail: skycia@uoguelph.ca [Department of Physics, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1 (Canada)

    2014-08-15

    The Brockhouse project at the Canadian Light Source plans the construction of three beamlines, two wiggler beamlines, and one undulator beamline, that will be dedicated to x-ray diffraction and scattering. In this work, we will describe the undulator beamline main components and performance parameters, obtained from ray tracing using XOP-SHADOW codes. The undulator beamline will operate from 4.95 to 21 keV, using a 20 mm period hybrid undulator placed upstream of the wiggler in the same straight section. The beamline optics design was developed in cooperation with the Brazilian Synchrotron - LNLS. The beamline will have a double crystal monochromator with the options of Si(111) or Si(311) crystal pairs followed by two mirrors in the KB configuration to focus the beam at the sample position. The high brilliance of the undulator source will produce a very high flux of ∼10{sup 13} photons/s and high energy resolution into a small focus of 170 μm horizontal and 20-60 μm vertical, depending on the optical configuration and energy chosen. Two multi-axis goniometer experimental stations with area detectors and analyzers are foreseen to enable diffraction, resonant and inelastic scattering experiments, and SAXS/WAXS experiments with high resolution and time resolving capabilities.

  7. Spectral properties of segmented undulators for the 7-GeV advanced photon source

    International Nuclear Information System (INIS)

    The effect of nonzero particle beam emittance and magnetic field errors on the on-axis spectral brightness (BTo) of long undulators is discussed. It is shown that the quadratic dependence of BTo on the number of undulator periods, N, is reduced by emittance to N-x with 1 ≤x < 2. Further reductions in the intensity result from random magnetic field errors present in the undulator. An approximate model for the intensity of the central core of radiation of the principle harmonics is discussed and the results compared to those from Monte Carlo-type calculations where emittance is explicitly accounted for. An estimation of the effects of random field errors on the on-axis brightness in the presence of nonzero particle emittance is made. For the particular case of undulators proposed for the 7-GeV Advanced Photon Source, the results indicate that 5-m-long devices segmented into two sections will provide the required spectral intensity of a single long undulator when both emittance and magnet errors are considered

  8. Locomotion and Depth Control of Robotic Fish with Modular Undulating Fins

    Institute of Scientific and Technical Information of China (English)

    Kin Huat Low

    2006-01-01

    This paper presents an environmental-friendly robotic system mimicking the undulating fins of a fish. To mimic the actual flexible fin of real fish, a fin-like mechanism with a series of connecting linkages is modeled and attached to the robotic fish, by virtue of a specially designed strip. Each link is able to turn and slide with respect to the adjacent link.These driving linkages are then used to form a mechanical fin consisting of several fin segments, which are able to produce undulations, similar to those produced by the actual fish fins. Owing to the modular and re-configurable design of the mechanical fin, we are able to construct biomimetic robotic fish with various swimming modes by fin undulations. Some qualitative and workspace observations by experiments of the robotic fish are shown and discussed.

  9. Design, construction and characterization of the compact ultrafast terahertz free-electron laser undulator

    Indian Academy of Sciences (India)

    B Biswas; V Kumar; S Chouksey; S Krishnagopal

    2008-12-01

    A compact ultrafast terahertz (CUTE) free-electron laser (FEL) is being developed at the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The undulator required for the CUTE-FEL has recently been developed. We have designed, built and characterized a variable gap, 5 cm period, 2.5 m long pure permanent magnet undulator in two identical segments. The tolerable error in the magnetic field was 1% in rms, and we have measured it to be 0.7%. The obtained rms phase shake is around 2°. To ensure that the trajectories do not have an exit error in position or angle, corrector coils have been designed. Shimming coils have been applied for both the undulator segments to reduce the amplitude of the betatron oscillations in the vertical trajectory. Details of novel corrector coils and soft iron shims are given and their performance is discussed.

  10. Circular polarization opportunities at the SASE3 undulator line of the European XFEL

    CERN Document Server

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni

    2016-01-01

    XFELs provide X-ray pulses with unprecedented peak brightness and ultrashort duration. They are usually driven by planar undulators, meaning that the output radiation is linearly polarized. For many experimental applications, however, polarization control is critical: besides the ability to produce linearly polarized radiation, one often needs the possibility of generating circularly polarized radiation with a high, stable degree of polarization. This may be achieved by using a first part of the XFEL undulator to produce bunching and then, by propagating the the bunched beam through an "afterburner" - a short undulator with tunable polarization, where only limited gain takes place. One of the issues that one needs to consider in this case is the separation of the circularly polarized radiation obtained in the radiator from the linearly polarized background produced in the first part of the FEL. In this article we review several methods to do so, including the inverse tapering technique. In particular, we use ...

  11. Knot undulator to generate linearly polarized photons with low on-axis power density.

    Science.gov (United States)

    Qiao, S; Ma, Dewei; Feng, Donglai; Marks, S; Schlueter, R; Prestemon, S; Hussain, Z

    2009-08-01

    Heat load on beamline optics is a serious obstacle for devices designed to generate pure linearly polarized photons in third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by implementing a figure-eight design configuration. As yet there has been no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel design and operational mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Additionally, the minimum photon energy capability of linearly polarized photons can be significantly extended by this method. PMID:19725682

  12. An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

    OpenAIRE

    Anania, M.P.; Brunetti, E; Wiggins, S M; Grant, D W; Welsh, G. H.; Issac, R.C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; van der Geer, S. B.; De Loos, M.J.; Poole, M.W.; Shepherd, B. J. A.; Clarke, J A

    2014-01-01

    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 106 per shot for a 100 period undulator, with a mean peak brilliance of 1 × 1018 photons/s/mrad2/mm2/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has ...

  13. Operation of a small-gap undulator on the NSLS X-ray Ring

    Energy Technology Data Exchange (ETDEWEB)

    Stefan, P.M.; Krinsky, S.; Rakowsky, G.; Solomon, L. [Brookhaven National Lab., Upton, NY (United States)

    1995-02-01

    The authors report results of an on-going experiment being carried out in the X13 straight section of the NSLS X-ray Ring which explores the limits of the operation of small-gap undulators. In particular, they discuss the operation of a 16 mm period small-gap undulator. At an electron beam current of 300 mA the variable gap vacuum chamber has been closed to an inner aperture of 3.8 mm with no effect on the electron beam lifetime. Measurements of the output radiation spectrum at a magnet gap of 7.5 mm are described.

  14. A new undulator for the extension of the spectral range of the CLIO FEL

    Energy Technology Data Exchange (ETDEWEB)

    Marcouille, O.; Berset, J.M.; Glotin, F. [LURE, Orsay (France)] [and others

    1995-12-31

    We built a new undulator in order to extend the lasing range of the CLIO infrared FEL. Presently, CLIO operates in the wavelength range 2 - 17 {mu}m. Beyond 14 {mu}m, the power decreases rapidly, because of the diffraction losses of the vacuum chamber (7 mm height and 2 m long). Thus, lasing at higher wavelengths implies installing a chamber with a height approximately twice. Then the minimum gap is increased and the maximum deflection parameter, K, is reduced from 2 to 1 : the laser tunability is greatly reduced. This is why a new undulator has been built.

  15. High efficiency energy extraction from a relativistic electron beam in a strongly tapered undulator

    CERN Document Server

    Sudar, Nicholas; Duris, Joe; Gadjev, Ivan; Polyaniy, Mikhail; Pogorelsky, Igor; Fedurin, Mikhail; Swinson, Christina; Babzien, Marcus; Kusche, Karl; Gover, Avi

    2016-01-01

    We present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54 cm long strongly tapered helical magnetic undulator, extracting over 30$\\%$ of the initial electron beam energy to coherent radiation. These results demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.

  16. Light's orbital angular momentum carried by helical undulator harmonics

    International Nuclear Information System (INIS)

    Spiral interference patterns between two different harmonic radiations from two tandem-aligned helical undulators were observed by a scanning fiber multi-channel spectrometer and a UV-CCD camera placed at the end of beamline downstream of S1 straight section in UVSOR-III. Using these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical predictions for every mode in the right or left circular polarization. The rotation of an interference pattern by rotating a polarizer was also observed. In this article, a theoretical background and a series of experimental results are described for the exotic property of undulator harmonics. (author)

  17. Observation of light's orbital angular momentum from helical undulator harmonics

    International Nuclear Information System (INIS)

    A spiral interference pattern between fundamental and second harmonic radiations form two tandem-aligned helical undulators was observed by scanning a fiber multi-channel spectrometer placed at the end of beamline downstream of S1 straight section in UVSOR. With these experiments, interference patterns were in good agreement with those by theoretical prediction for right and left circular polarization modes. Also, similar interference measurement was done by using a CCD camera. With this measurement, we observed a rotation of spiral pattern by changing the undulator gap. (author)

  18. Channeling and Radiation of Electrons in Silicon Single Crystals and Si1−xGex Crystalline Undulators

    DEFF Research Database (Denmark)

    Backe, H.; Krambrich, D.; Lauth, W.;

    2013-01-01

    potential of the silicon single crystals. Radiation from a crystalline undulator, produced at the Aarhus University (UAAR), has been investigated at the Mainz Microtron electron accelerator facility MAMI. The 4-period epitaxially grown strained layer Si1−xGex undulator had a period length λu = 9.9 μm...

  19. Comparison of different undulator schemes with superimposed alternating gradients for the VUV-FEL at the TESLA Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Pflueger, J.; Nikitina, Y.M. [DESY/HASYLAB, Hamburg (Germany)

    1995-12-31

    For the VUV-FEL at the TESLA Test Facility an undulator with a total length of 30 m is needed. In this study three different approaches to realize an undulator with a sinusoidal plus a superimposed quadrupolar field were studied with the 3D code MAFIA.

  20. Sea-floor undulations formation by turbidity flow in the Adra prodeltaic system, western Mediterranean Basin: comparison between numerical simulation and real data

    Science.gov (United States)

    Fernández-Salas, Luis Miguel; Barcenas, Patricia; Macias, Jorge

    2016-04-01

    Numerical simulation of turbidity currents are used to study the formation of the seafloor undulations in the Adra prodeltaic system, western Mediterranean basin. A series of elongated and subparallel bathymetric undulations are distinguished in the foreset-bottomsets domain of the Holocene pro-deltaic wedge associated with the Adra river. In this study, multibeam data and surficial sediment samples have been used in comparison with numerical simulation to propose an evolutionary model of the seafloor undulations. Numerical model suggests that the depositional basin slope gradient is one of the factors more influent in the seafloor undulations formation. The simulations allowed to observe as seafloor undulations are approximately in phase with the undulations of the turbidity layer. Therefore, undulations are associated with Froude-supercritical flow. The upslope and downslope undulations boundaries are limited by a hydraulic jump where the flow makes a conversion from supercriticial flow (Fr>1) to subcritical flow (Frproject TESELA (P11-RNM7069)

  1. Design, fabrication, installation and commissioning of water-cooled beam viewer for undulator front-ends of Indus-2

    International Nuclear Information System (INIS)

    A water-cooled beam viewer is developed indigenously to observe the bright synchrotron light coming from recently installed undulators in Indus-2 storage ring at RRCAT, Indore. The beam viewer is installed in the undulator front-end. The frontend is a long ultra high vacuum (UHV) assembly consisting of UHV valves, shutters, vacuum pumps and beam diagnostic devices. The front-end acts as an interface between Indus-2 ring and beamline. The beam viewer uses a fluorescent sheet of Chromium doped Alumina (CHROMOX) which produces visible fluorescent light when bright synchrotron light from the undulator falls on it. This visible fluorescent light is observed through a glass window by a CCD camera. The beam viewer has been successfully tested and commissioned in Indus-2 front-end for undulator. At present, the beam viewer is operating under vacuum of 5 x 10-10 mbar in the Indus-2 undulator front-end

  2. Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract)

    Science.gov (United States)

    Ishikawa, T.; Maezawa, H.; Nomura, M.; Ando, M.

    1989-07-01

    Since undulator light is sharply collimated itself, it can be effectively monochromatized by a perfect crystal. An x-ray double-crystal monochromator with a fixed exit has been designed and built for the use of undulator light from a 60-period undulator at Photon Factory (beamline 2A). Available Bragg angle ranges from 7° to 80°. Angle scan is made by means of a goniometer outside the vacuum chamber, with the finest step of 0.1 arcsec. Magnetic fluid is used as the vacuum seal of the feedthrough. The fixed exit beam position is kept by translating the second crystal along the two mechanical guides: one for normal and the other for parallel to the crystal surface. Adjustment of the parallelity of two crystals is made manually with flexible wires. Since a total power in the central coherent portion which is limited by a 1×1-mm2 slit is not so much, a stable operation is possible without cooling the crystal. Currently, InSb (111) reflection is used. The diffracting planes of the first cyrstal is 1° off from the surface and the second is the symmetric reflection. At its fifth harmonics, brilliant undulator light of approximately 1012 photons/s mm2 with 1-eV energy resolution is available (E=2 keV).

  3. Modeling the formation of undulations of the coastline: the role of tides

    NARCIS (Netherlands)

    van der Vegt, M.; Schuttelaars, H.; de Swart, H.E.

    2007-01-01

    An idealized model is developed and analyzed to investigate the relevance of tidal motion for the emergence of undulations of a sandy coastline. The model describes feedbacks between tidal and steady flow on the inner shelf, sand transport in the nearshore zone and an irregular coastline. It is demo

  4. Beam heat load measurements in the cold bore superconductive undulator in ANKA

    CERN Document Server

    Casalbuoni, S; Hagelstein, M; Zimmermann, F; Rossmanith, Robert; Kostka, Barbara; Mashkina, Elena; Steffens, Erhard; Bernhard, Axel; Wollmann, Daniel; Baumbach, Tilo

    2007-01-01

    Measurements of the beam-induced heat load in the ANKA cold-bore superconductive undulator are summarized. The strength of the two dominating effects, resistive wall heating and heating by electron bombardment, depends on the beam parameters and the gap width.

  5. Longitudinal impedance and wake from XFEL undulators. Impact on current-enhanced SASE schemes

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, G.; Saldin, E.; Schneidmiller, E.; Yurkov, M.

    2007-06-15

    In this article we derive longitudinal impedance and wake function for an undulator setup with arbitrary undulator parameter, taking into account a finite transverse size of the electron bunch. Earlier studies considered a line density-distribution of electrons instead. We focus our attention on the long-wavelength asymptote (compared with resonance wavelength), at large distance of the electron bunch from the undulator entrance compared to the overtaking length, and for large vacuumchamber size compared to the typical transverse size of the field. These restrictions define a parameter region of interest for practical applications. We calculate a closed expression for impedance and wake function that may be evaluated numerically in the most general case. Such expression allows us to derive an analytical solution for a Gaussian transverse and longitudinal bunch shape. Finally, we study the feasibility of current-enhanced SASE schemes (ESASE) recently proposed for LCLS, that fall well-within our approximations. Numerical estimations presented in this paper indicate that impedance-induced energy spread is sufficient to seriously degrade the FEL performance. Our conclusion is in contrast with results in literature, where wake calculations for the LCLS case are given in free-space, as if the presence of the undulator were negligible. (orig.)

  6. Simultaneous ground-satellite observations of meso-scale auroral arc undulations

    Science.gov (United States)

    Motoba, T.; Hosokawa, K.; Ogawa, Y.; Sato, N.; Kadokura, A.; Milan, S. E.; Lester, M.

    2012-06-01

    We present simultaneous ground-based and in situ measurements of a train of meso-scale (about 100-300 km) auroral arc undulations, occurring in the postmidnight sector (˜1 MLT) between 0040 UT and 0054 UT on September 21, 2009. The undulations appeared at the auroral poleward boundary, and then moved eastward with a speed of 0.9-2.2 km s-1. Dynamic behaviors of the associated meso-scale ionospheric plasma flows and current systems were also detected with the ground-based magnetometer and radar measurements within the all-sky camera field-of-view. During the interval of interest, simultaneous Cluster observations in the central near tail region (11-14 RE down tail) were available, and especially the ionospheric footprint of Cluster 2 (CL2) was close to the optical auroral forms. CL2 observed strong fluctuations in the in situ magnetic field with amplitude of 5-10 nT whenever a bright arc area, and its trailing adjacent area, of the auroral undulations passed its ionospheric footprint. Such in situ magnetic field changes at CL2 could be considered as a manifestation of localized upward and downward field-aligned current sheets moving eastward at the central near-Earth tail boundary, linked to the meso-scale auroral undulation structures.

  7. Final construction of the C.R.E.O.L. 8 millimeter period hybrid undulator

    Energy Technology Data Exchange (ETDEWEB)

    Tesch, P.; Gallagher, J.; Elias, L. [Center for Research and Education in Optics and Lasers, Orlando, FL (United States)

    1995-12-31

    The construction of an 8 millimeter period hybrid undulator for the C.R.E.O.L. high power far-infared free electron laser has just been completed. This FEL is expected to come on-line in the fall of 1995 and produce close to a kilowatt of continuous power at wavelengths of 225 - 800 microns. The undulator has extremely precise mechanical tolerances and high field uniformity allowing for high electron beam recovery rates. Almost complete beam recovery is required for DC operation at high currents. A novel method for measuring the magnetic properties of individual magnets and sorting the magnets to reduce magnetic field errors will be reported. The peak field and phase errors of the undulator without the pole pieces are reduced through a magnet ordering procedure. These errors are further reduced by inserting and tuning adjustable pole pieces. The reduction of field errors through these two techniques will be presented. An analysis of the final undulator errors and the results of measurements of the mechanical tolerances will be presented.

  8. Brilliant radiation sources by laser-plasma accelerators and optical undulators

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander

    2012-09-06

    This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

  9. A robotic device with a passive undulating ribbon fin: kinematics and propulsive performance

    Science.gov (United States)

    Liu, Hanlin; Curet, Oscar

    2015-11-01

    Many aquatic animals swim with high maneuverability using undulating ribbon fins. In this type of swimming, the organism propels by sending one or multiple traveling waves along an elongated fin. In previous work, robotic models with fully actuated fins where the parameters of the traveling waves are fully prescribed have been used to study the propulsive performance and fluid dynamics of this type of propulsion. However, less work has been done in ribbon fins with passively undulating waves. In this work, we use a robotic device to study the kinematics and propulsive performance of a passively undulating ribbon fin. The physical model is composed of fifteen rays interconnected with a membrane. Only two rays are actuated while the other rays are free to rotate through a common axis. The robotic fin was tested in a flume at different flow conditions. In a series of experiments we measured fin kinematics, propulsive forces and power consumption. As the leading two rays are actuated, a traveling wave with decaying amplitude passes through the passive rays. As the frequency of the actuated rays increases, the enclosed area of the undulating wave and the traveling wave frequency increase while the wavelength decreases. Our data also show that the propulsive force generated by the fin scaled with the enclosed area and the square of the relative velocity between incoming flow and traveling wave. These results suggest that both natural swimmers and underwater vehicles using ribbon-fin-based propulsion can potentially take advantage of passive undulating waves. National Science Foundation Grant No. 1420774

  10. Tailoring the amplification of attosecond pulse through detuned X-ray FEL undulator.

    Science.gov (United States)

    Kumar, Sandeep; Kang, Heung-Sik; Kim, Dong Eon

    2015-02-01

    We demonstrate that the amplification of attosecond pulse in X-ray free electron laser (FEL) undulator can be tailored. The characteristic of the amplification of an isolated attosecond pulse in the FEL undulator is investigated. An isolated 180 attoseconds full width half maximum (FWHM) pulse at 1.25 nm with a spectral bandwidth of 1% is injected into an undulator. The simulation results show that for a direct seeding of 3MW, the seed is amplified to the peak power of 106 GW (40 μJ, an output pulse-width of 383 attoseconds) in the presence of a detuning at FEL resonance condition in 100-m long undulator. We note that the introduction of detuning leads to the better performance compared to the case without detuning: shorter by 15.5% in a pulse-width and higher by 76.6% in an output power. Tapering yields a higher power (116% increases in the output power compared to the case without detuning) but a longer pulse (15.4% longer in the pulse-width). It was observed that ± Δλ(r)/8 (Δλ(r)/λ(r) ~1%) is the maximum degree of detuning, beyond which the amplification becomes poor: lower in the output power and longer in the pulse duration. The minimum power for a seed pulse needs to be higher than 1 MW for the successful amplification of an attosecond pulse at 1.25 nm. Also, the electron beam energy-spread must be less than 0.1% for a suitable propagation of attosecond pulse along the FEL undulator under this study. PMID:25836141

  11. Tuning and characterization of the {open_quotes}Teufel{close_quotes}-undulator

    Energy Technology Data Exchange (ETDEWEB)

    Verschuur, J.W.J.; Ernst, G.J.; Witteman, W.J. [Univ. of Twente, Enschede (Netherlands)

    1995-12-31

    Three important criteria are used to tune the undulator are: reduce longitudinal phase errors, have approximately equal two plane focusing and have a good overlap between the electron beam and the optical beam. Although these criteria are the main design goals it is hard to meet them directly from the assembling. Small errors inevitably appear during the assembly, even when care is taken to keep the tolerances as tight as possible. The magnetic field was constantly monitored during construction using the pulsed wire method. However some kind of tuning mechanism is always needed to improve the performance of the undulator. The undulator we designed and build is of the Hybrid type, i.e. permanent magnets and high permeable poles. The well known method of using small permanent magnets to correct the field errors is nearly impossible due to the presence of iron poles. Hence, as a logical step, we decided to try to correct the various errors with shims in the form of small iron plates. The shims were put on the pole face at the edge of the poles. Different configurations were used to correct the different kind of errors. In the presentation an overview of the various shim configurations will be discussed. Steering errors are quite easy to correct, since only dipole fields are involved. We did put quite some effort in correcting the quadrupole errors. Gradients dBy/dx and dBx/dy were easy to correct with two shims on one side. The other gradients, on the other hand needed extensive shimming to be corrected. The error correction is limited by the presence of sextupole errors. We even found by experience that sextupole errors increased with the number of shims used. The ratio of the focusing strength of the undulator is measured to be 3/2, being slightly stronger in the direction of the wiggle motion. Longitudinal phase errors are introduced by amplitude and wavelength deviations in the undulator.

  12. Brilliant radiation sources by laser-plasma accelerators and optical undulators

    International Nuclear Information System (INIS)

    This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

  13. Short note on undulator alignments and beam tolerances for the APS FEL at 220 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Dejus, R.J.; Vasserman, I.B.

    1999-10-08

    The APS FEL consists of a series of undulators that must be carefully aligned for optimum gain and high spectral output. In order to get a better understanding of acceptable tolerance levels for undulator alignments and for the electron beam, the authors have performed computer calculations to simulate misalignments of one undulator (undulator number 2) with respect to adjacent undulators and to check the sensitivity to unmatched beam parameters ({alpha} and {beta}) at the entrance and to a noncentered incident beam x{sub o}, x{sub o}{prime}, y{sub o}, y{sub o}{prime}. They have not simulated horizontal misalignments because the undulators focus only in the vertical direction and horizontal alignments are therefore much more relaxed than vertical alignments. The exact placement and strength of the quadrupoles in the breaks need also to be addressed in follow up studies and are not presented here. Further, inherent undulator magnetic field errors have not been investigated here and will also be the subject for another study. Note, the tolerances listed in this note may be used for guidance only and will need to be updated when they have updated beam parameters.

  14. Monte Carlo Studies of the Radiation Fields in the Linac Coherent Light Source Undulators and of the Corresponding Signals in the Cerenkov Beam Loss Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Santana Leitner, Mario; Fasso, Alberto; Fisher, Alan S.; Nuhn, Heinz D.; /SLAC; Dooling, Jeffrey C.; Berg, William; Yang, Bin X.; /Argonne

    2010-09-14

    In 2009 the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Center started free electron laser (FEL) operation. In order to continue to produce the bright and short-pulsed x-ray laser demanded by FEL scientists, this pioneer hard x-ray FEL requires a perfectly tailored magnetic field at the undulators, so that the photons generated at the electron wiggling path interact at the right phase with the electron beam. In such a precise system, small (>0.01%) radiation-induced alterations of the magnetic field in the permanent magnets could affect FEL performance. This paper describes the simulation studies of radiation fields in permanent magnets and the expected signal in the detectors. The transport of particles from the radiation sources (i.e. diagnostic insert) to the undulator magnets and to the beam loss monitors (BLM) was simulated with the intra nuclear cascade codes FLUKA and MARS15. In order to accurately reproduce the optics of LCLS, lattice capabilities and magnetic fields were enabled in FLUKA and betatron oscillations were validated against reference data. All electron events entering the BLMs were printed in data files. The paper also introduces the Radioactive Ion Beam Optimizer (RIBO) Monte Carlo 3-D code, which was used to read from the event files, to compute Cerenkov production and then to simulate the optical coupling of the BLM detectors, accounting for the transmission of light through the quartz.

  15. Method of Aeromagnetic Gradients Anomaly Continuation from Undulate Surface to Plane and Its Application%航磁梯度数据的曲化平方法及应用

    Institute of Scientific and Technical Information of China (English)

    李海侠; 张小凌; 刘红战

    2013-01-01

    将插值-迭代法移植到航磁梯度数据的曲化平计算中,利用长方体模型验证方法的有效性和计算精度.计算结果表明,利用插值-迭代法对梯度异常进行曲化平可以达到较好的精度,平均相对误差小于7%.将曲化平处理前后的梯度数据分别应用于解析信号法和欧拉反褶积法,对比结果表明,利用曲面上梯度计算的解析信号极大值明显偏离了长方体磁源的中心位置,对长方体边界反映不明显,而利用化平后的梯度计算解析信号能够更好地反映场源体的边界和中心位置;利用曲面上的梯度进行欧拉反演的结果比较分散,而曲化平后的梯度数据反演的结果则比较集中,可以较好地反映出长方体场源四个角点的位置.以上结果证明梯度数据经过曲化平处理后可以改善这两种解释方法的应用效果.%The interpolation-iterative method is applied to aeromagnetic gradient anomaly continuation from undulate surface to plane in this paper,and a prism model is constructed to demonstrate the effectiveness and accuracy of the method.The calculated results show that the technique has good accuracy and that all mean relative errors of computed results are less than 7%.Gradient anomalies on undulate surface and gradient anomalies after continuation from undulate surface to plane are applied to analytic signal calculation and Euler deconvolution method respectively.Comparisons of the results indicate that the maxima of analytic signal calculated by gradient anomalies on undulate surface deviate obviously from the center location of the prism magnetic source,and that the position of prism boundaries are not clear.However,the analytic signal calculated by gradient anomalies after continuation from undulate surface to plane can be successfully used to estimate the center and boundaries position of prism.The solutions of Euler deconvolution method calculated by gradient anomalies on undulate surface

  16. A Novel Diagnostics of Ultrashort Electron Bunches Based on Detection of Coherent Radiation from Bunched Electron Beam in an Undulator

    CERN Document Server

    Saldin, Evgeny L; Yurkov, Mikhail V

    2004-01-01

    We propose a new method for measurements of the longitudinal profile of 100 femtosecond electron bunches for X-ray Free Electron Lasers (XFELs). The method is based on detection of coherent undulator radiation produced by modulated electron beam. Seed optical quantum laser is used to produce exact optical replica of ultrashort electron bunches. The replica is generated in apparatus which consists of an input undulator (energy modulator), and output undulator (radiator) separated by a dispersion section. The radiation in the output undulator is excited by the electron bunch modulated at the optical wavelength and rapidly reaches a hundred-MW-level power. We then use the now-standard method of ultrashort laser pulse-shape measurement, a tandem combination of autocorrelator and spectrum (FROG -- frequency resolved optical gating) providing real-time single-shot measurements of the electron bunch structure. The big advantage of proposed technique is that it can be used to determine the slice energy spread and emi...

  17. Radiation emission at channeling of electrons in a strained layer Si1-xGex undulator crystal

    DEFF Research Database (Denmark)

    Backe, H.; Krambrich, D.; Lauth, W.;

    2013-01-01

    Experiments have been performed at the Mainz Microtron MAMI to explore the radiation emission spectra from a crystalline undulator at electron beam energies of 270 and 855 MeV. The epitaxially grown graded composition strained layer Si1-xGex undulator had 4-period with a period length View the Math......ML source. Spectra taken at the beam energy of 270 MeV at channeling in the undulating (110) planes exhibit a broad excess yield around the theoretically expected photon energies of 0.069 MeV, as compared with a flat silicon reference crystal. Model calculations on the basis of synchrotron-like radiation...... emission from finite single arc elements, taking into account also coherence effects, suggest that evidence for a weak undulator effect has been observed for the first time for electrons....

  18. Ice Velocity Mapping of Ross Ice Shelf, Antarctica by Matching Surface Undulations Measured by Icesat Laser Altimetry

    Science.gov (United States)

    Lee, Choon-Ki; Han, Shin-Chan; Yu, Jaehyung; Scambos, Ted A.; Seo, Ki-Weon

    2012-01-01

    We present a novel method for estimating the surface horizontal velocity on ice shelves using laser altimetrydata from the Ice Cloud and land Elevation Satellite (ICESat; 20032009). The method matches undulations measured at crossover points between successive campaigns.

  19. Analysis of pulsed wire method for field integral measurements in undulators

    Indian Academy of Sciences (India)

    Vinit Kumar; Ganeshwar Mishra

    2010-05-01

    Pulsed wire technique is a fast and accurate method for the measurement of first and second field integrals of undulators used in free-electron lasers and synchrotron light sources. In this paper, we present a theoretical analysis of this technique by finding out the analytic solution of the differential equation for the forced vibration of the wire taking dispersion due to stiffness into account. Method of images is used to extend these solutions to include reflections at the ends. For long undulators, the effect of dispersion of the acoustic wave in the wire could be significant and our analysis provides a method for the evaluation of the magnetic field profile even in such cases taking the effect due to dispersion into account in an exact way.

  20. Beam dynamics studies during commissioning of two undulators in Indus-2

    International Nuclear Information System (INIS)

    Indus-2, a synchrotron light source facility at RRCAT, Indore is in continuous operation at 2.5 GeV, generating the synchrotron radiation from its bending magnets. For enhancing the intensity of synchrotron radiation, two planar undulators have been installed and successfully commissioned with the Indus-2 electron beam. Various beam dynamical challenges such as beam accumulation, beam energy ramping and storage at 2.5 GeV have been addressed to ensure the smooth commissioning of these devices. Moreover, due to interaction of the stored beam with magnetic field of undulators, various parameters of the electron beam get changed. In this paper, the beam dynamics studies to ensure the smooth commissioning of these devices and its measured effect on beam parameters have been presented. (author)

  1. A hybrid type undulator for far-infrared FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Zako, A.; Miyauchi, Y.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two FEL facilities of the FELI are now operating in the wavelength range of 1-20 {mu}m. A 3.2-m hybrid type undulator ({lambda}{sub u}=80mm, N=40) has been designed for far-infrared FELs and will be installed in December. It can cover the wavelength of 20-60 {mu}m by changing K-value from 1 to 2.7 for a 28.0-MeV electron beam. It is composed of ferrite magnetic poles and Sm-Co permanent magnets. Commonly wound coils induce alternating magnetic field in ferrite poles. Combination of the induced field and the permanent magnet field can controls the magnetic field between the undulator gap.

  2. Three-dimensional numerical investigations of the laser-beam interactions in an undulator

    Institute of Scientific and Technical Information of China (English)

    DENG Hai-Xiao; LIN Tang-Yu; YAN Jun; WANG Dong; DAI Zhi-Min

    2011-01-01

    Laser-beam interaction in an undulator is commonly suggested in the development of free electron laser(FEL)schemes. In this paper, a three-dimensional algorithm is developed to assist in laser-beam interaction simulation in an undulator, which is built on the basis of the fundamentals of electrodynamics, i.e.the electron's behavior is determined by the magnetic field and the laser electric field in the time domain. On the basis of the algorithm, the detuning effect in a laser heater, the carrier envelope phase effect of a few-cycle laser in attosecond X-ray FEL schemes and output wavelength tuning in a high gain harmonic generation FEL are numerically discussed.

  3. Tapering studies for Terawatt level X-ray FELs with a superconducting undulator

    CERN Document Server

    Emma, Claudio; Emma, Paul; Huang, Zhirong; Pellegrini, Claudio

    2015-01-01

    We study the tapering optimization scheme for a short period, less than two cm, superconducting undulator, and show that it can generate 4 keV X-ray pulses with peak power in excess of 1 terawatt, using LCLS electron beam parameters. We study the e?ect of undulator module length relative to the FEL gain length for continous and step-wise taper pro?les. For the optimal section length of 1.5m we study the evolution of the FEL process for two di?erent superconducting technologies NbTi and Nb3Sn. We discuss the major factors limiting the maximum output power, particle detrapping around the saturation location and time dependent detrapping due to generation and ampli?cation of sideband modes.

  4. Chamber Surface Roughness and Electron Cloud for the Advanced Photon Source Superconducting Undulator

    OpenAIRE

    Boon, Laura; Harkay, Katherine

    2013-01-01

    The electron cloud is a possible heat source in the superconducting undulator (SCU) designed for the Advanced Photon Source (APS), a 7-GeV electron synchrotron radiation source at Argonne National Laboratory. In electron cloud generation extensive research has been done, and is continuing, to understand the secondary electron component. However, little work has been done to understand the parameters of photoemission in the accelerator environment. To better understand the primary electron gen...

  5. Fast continuous energy scan with dynamic coupling of the monochromator and undulator at the DEIMOS beamline.

    Science.gov (United States)

    Joly, L; Otero, E; Choueikani, F; Marteau, F; Chapuis, L; Ohresser, P

    2014-05-01

    In order to improve the efficiency of X-ray absorption data recording, a fast scan method, the Turboscan, has been developed on the DEIMOS beamline at Synchrotron SOLEIL, consisting of a software-synchronized continuous motion of the monochromator and undulator motors. This process suppresses the time loss when waiting for the motors to reach their target positions, as well as software dead-time, while preserving excellent beam characteristics.

  6. A Study on Inviscid Flow with a Free Surface over an Undulating Bottom

    OpenAIRE

    Srikumar Panda

    2016-01-01

    In this paper, the problem involving inviscid flow with a free surface over an undulating bottom is studied within the framework of linear theory. Applying perturbation analysis in conjunction with the Fourier transform technique, the boundary value problem arising from the flow problem is solved analytically. Behaviour of both interface and free-surface profiles, which are unknown at the outset, are analyzed. It is found that each profile (interface and free-surface) possesses a ...

  7. On simulating lipid bilayers with an applied surface tension: periodic boundary conditions and undulations.

    OpenAIRE

    Feller, S E; Pastor, R W

    1996-01-01

    As sketched in Fig. 1, a current molecular dynamics computer simulation of a lipid bilayer fails to capture significant features of the macroscopic system, including long wavelength undulations. Such fluctuations are intrinsically connected to the value of the macroscopic (or thermodynamic) surface tension (cf. Eqs. 1 and 9; for a related treatment, see Brochard et al., 1975, 1976). Consequently, the surface tension that might be evaluated in an MD simulation should not be expected to equal t...

  8. Undulative induction electron accelerator for the waste and natural water purification systems

    CERN Document Server

    Kulish, Victor V; Gubanov, I V

    2001-01-01

    The project analysis of Undulative Induction Accelerator (EH - accelerator) for the waste and natural water purification systems is accomplished. It is shown that the use of the four-channel design of induction block and the standard set of auxiliary equipment (developed earlier for the Linear Induction Accelerators - LINACs) allow to construct commercially promising purification systems. A quality analysis of the accelerator is done and the optimal parameters are chosen taking into account the specific sphere of its usage.

  9. Beamline 9.0.1 - a high-resolution undulator beamline for gas-phase spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bozek, J.D.; Heimann, P.A.; Mossessian, D. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Beamline 9.0.1 at the Advanced Light Source is an undulator beamline with a Spherical Grating Monochromator (SGM) which provides very high resolution and flux over the photon energy range 20-320eV. The beamline has been used primarily by the atomic and molecular science community to conduct spectroscopy experiments using electron, ion and fluorescence photon detection. A description of the beamline and its performance will be provided in this abstract.

  10. Effects of undulators on the ALS: The early work on the LBL [Lawrence Berkeley Laboratory

    International Nuclear Information System (INIS)

    In this paper we describe the early work carried out at LBL on the consequences of installing insertion devices (wigglers and undulators) on the beam dynamics of the ALS. This included analytical and tracking studies, and led to an insight to the reasons behind the predicted reduction in dynamic aperture. For completeness, a description of the unperturbed storage ring characteristics are also given. 3 refs., 16 figs., 2 tabs

  11. Initial studies of Bremsstrahlung energy deposition in small-bore superconducting undulator structures in linac environments

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, T.; Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    One of the more promising technologies for developing minimal-length insertion devices for linac-driven, single-pass Free Electron Lasers (FELs) operating in the x-ray range is based on the use of superconducting (SC) materials. In recent FEL simulations, for example, a bifilar helical SC device with a 2 cm period and 1.8 T field was found to require a 30 m saturation length for operation at 1.5{Angstrom} on a 15 GeV linac, more than 40% shorter than an alternative hybrid/permanent magnet (hybrid/PM) undulator. AT the same time, however, SC technology is known to present characteristic difficulties for insertion device design, both in engineering detail and in operation. Perhaps the most critical problem, as observed, e.g., by Madey and co-workers in their initial FEL experiments, was the frequent quenching induced by scattered electrons upstream of their (bifilar) device. Postulating that this quenching was precipitated by directly-scattered or bremsstrahlung-induced particle energy deposited into the SC material or into material contiguous with it, the importance of numerical and experimental characterizations of this phenomenon for linac-based, user-facility SC undulator design becomes evident. In this paper we discuss selected prior experimental results and report on initial EGS4 code studies of scattered and bremsstrahlung induced particle energy deposition into SC structures with geometries comparable to a small-bore bifilar helical undulator.

  12. A Helical Undulator Wave-guide Inverse Free-Electron Laser

    International Nuclear Information System (INIS)

    With recent success in high gradient, high-energy gain IFEL experiments at the UCLA Neptune Laboratory, future experiments are now being contemplated. The Neptune IFEL was designed to use a tightly focused, highly diffracting, near-TW peak power 10 micron laser. This choice of laser focusing, driven by power-handling limitations of the optics near the interaction region, led to design and use of a very complex undulator, and to sensitivity to both laser misalignment and focusing errors. As these effects limited the performance of the IFEL experiment, a next generation experiment at Neptune has been studied which avoids the use of a highly diffractive laser beam through use of a waveguide. We discuss here the choice of low-loss waveguide, guided mode characteristics and likely power limitations. We also examine a preferred undulator design, which is chosen to be helical in order to maximize the acceleration achieved for a given power. With the limitations of these laser and undulator choices in mind, we show the expected performance of the IFEL using 1D simulations. Three-dimensional effects are examined, in the context of use of a solenoid for focusing and acceleration enhancement

  13. Control software of a variably polarizing undulator (APPLE type) for SX beamline in the SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Yoichi [Kansai Research Establishment, Japan Atomic Energy Research Institute, Mikazuki, Hyogo (Japan); Shimada, Taihei; Miyahara, Yoshikazu

    1999-12-01

    This paper describes the control software of a variably polarizing undulator (APPLE Type) that was installed at the SX beamline (cell number 23) in the SPring-8 storage ring in February, 1998. This undulator produces a polarized radiation in the energy range of soft X-ray by changing the gap distance between two pairs of permanent magnet arrays (gap movement). The main characteristic of the undulator is a capability to generate right and left circular polarization alternately at a period of 2 sec (0.5 Hz) by high speed phase-shifting (periodic phase movement). The developed software makes a fast correction of the closed orbit distortion (COD) of an electron beam by exciting steering magnets at a rate of time interval of 24 msec (42 Hz) during the movement of magnet arrays. Also, the software is capable to put these magnet arrays into a constant periodic phase movement with an error less than 0.1% for the period of 2 sec. The software was developed in accordance with the directions of SPring-8 standard for software development. (author)

  14. Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

    Institute of Scientific and Technical Information of China (English)

    Md. Mahbubar Rahman; Yasuyuki Toda; Hiroshi Miki

    2011-01-01

    The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin's principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

  15. An elliptically-polarizing undulator with phase adjustable energy and polarization

    International Nuclear Information System (INIS)

    The authors present a planar helical undulator designed to produce elliptically polarized light. Helical magnetic fields may be produced by a variety of undulators with four parallel cassettes of magnets. In their design, all cassettes are mounted in two planes on slides so that they may be moved parallel to the electron beam. This allows the undulator to produce x-rays of left- or right-handed elliptical or circular polarization as well as horizontal or vertical linear polarization. In model calculations, they have found that by sliding the top pair of rows with respect to the bottom pair, or the left pair with respect to the right pair, they retain the polarization setting but change the magnetic field strength, and hence the x-ray energy. This allows them to select both energy and polarization by independent phase adjustments alone, without changing the gap between the rows. Such a design may be simpler to construct than an adjustable gap machine. The authors present calculations that model its operation and its effects on an electron beam

  16. Performance of an undulator for visible and UV FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Miyauchi, Y.; Zako, A.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two infrared free electron lasers (FELs) of the FELI project are now operating in the wavelength range of 1-20{mu}m. A 2.68-m undulator has been constructed for visible and UV FELs covering the wavelength of 1-0.2{mu}m for 100-165 MeV electron beams. It generates alternating, horizontal magnetic field, and wiggles electron beam on a vertical plane. The undulator length and period are 2.68m and 40mm, respectively. The gap of undulator magnets can be changed remotely by using servomotors with an accuracy of 1 {mu}m from the control room. The maximum K-value and related magnetic field strength are 1.9 and 0.5T, respectively, when its gap is set to the minimum value of 16mm. In order to minimize magnetic field reduction due to radiation damage, Sm-Co permanent magnet was adopted. Its structure and the results of magnetic field measurement will be reported.

  17. The construction of a 9-pole prototype for SRRC U-10 undulator

    International Nuclear Information System (INIS)

    A 9-pole undulator prototype with a magnetic period length of 10 cm was designed and constructed to examine the mechanical and magnetic field performance. The hybrid permanent magnet structure was optimized by using 2D PANDIRA and 3D TOSCA magnetostatic codes. A half period magnet model was also fabricated to verify the magnetic field strength on-axis and the transverse field roll-off within 0.1% in the good field region of ±10 mm at a minimum gap of 22 mm. The end pole configurations, as equipped with either two tunable permanent magnetic rotators or steering coil correctors were designed for minimizing the deviation of the magnetic field strength integrals. The magnet structures were mounted on a 2 meter long C-frame support structure in which the gap could be moved in parallel and phase motion. The field characteristics and measurement results between the adjustable gap undulator (AGU) and the hybrid adjustable phase undulator (APU) were also presented

  18. Design of a transmission grating hard X-ray spectrometer for laser-driven undulator sources

    Energy Technology Data Exchange (ETDEWEB)

    Werle, Christian; Maier, Andreas; Zeitler, Benno; Delbos, Niels; Gruener, Florian [University of Hamburg - CFEL, Hamburg (Germany); Kajumba, Nathaniel [Ludwig Maximilian Univ., Muenchen (Germany)

    2013-07-01

    State-of-the-art laser-driven undulator sources are already becoming very versatile and powerful light sources, especially due to their wavelength tunability and ultra-short pulses. However, being still in development, they suffer from instabilities, which can make the spectral characterization of their radiation rather challenging, especially in the few-nm range. The hard X-ray transmission grating spectrometer, presented in this talk, was specifically optimized to tackle these difficulties. Its simple base design and its fully motorized optical components grant a high degree of flexibility during operation, fitting nicely to the nature of this radiation source. During calibration the device has been proven to measure wavelengths from 18 nm to 5 nm, but was in general also designed to address the sub-nm range. Following these test runs, the spectrometer was installed during a undulator campaign and was successfully used to measure laser-driven undulator radiation from 100 eV up to 300 eV, being the highest energy photons ever demonstrated with such a source.

  19. Image tuning techniques for enhancing the performance of pure permanent magnet undulators with small gap/period ratios

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    The on-axis field of a small-gap undulator constricted out of pure permanent magnet (PM) blocks arranged in an alternating-dipole (i.e., 2 dipoles/period) array can be substantially varied by positioning monolithic permeable plates above and below the undulator jaws. This simple technique, which can be used to control the 1st harmonic energy in conventional synchrotron radiation (SR) or Free Electron Laser (FEL) applications requiring sub-octave tuning, can also be shown to suppress magnetic inhomogeneities that can contribute to the undulator`s on-axis field errors. If a standard 4 block/period Halbach undulator, composed of PM blocks with square cross sections, is rearranged into an alternating-dipole array with the same period, the peak field that can be generated with superimposed image plates can substantially exceed that of the pure-PM Halbach array. This design technique, which can be viewed as intermediate between the {open_quotes}pure-PM{close_quotes} and standard {open_quotes}hybrid/PM{close_quotes} configurations, provides a potentially cost-effective method of enhancing the performance of small-gap, pure-PM insertion devices. In this paper we report on the analysis and recent characterization of pure-PM undulator structures with superimposed image plates, and discuss possible applications to FEL research.

  20. Quantitative nanoscale characterization of undulated silicon-germanium/silicon(100) epitaxial thin films

    Science.gov (United States)

    Wu, Chi-Chin

    Heteroepitaxial thin films are important for the fabrication of advanced devices and as model systems for understanding fundamental materials phenomena. Depending on the growth conditions, film thickness, and extent of lattice mismatch at the film/substrate interface during growth, the epitaxial film will undergo morphological surface evolution to help release the stored elastic strain energy. For low-mismatched structures, a compressively-strained film often roughens and/or forms misfit dislocations after achieving a characteristic thickness. Using undulated Si1-xGex/Si(100) thin films, this work focuses on measurement of quantitative nanoscale variations of compositional and strain/stress fields within roughened heteroepitaxial films. The research was initiated by calculating local and overall stresses for roughened films assuming a sinusoidal film geometry with finite element (FE) models. Chemical wet etching was then applied to experimentally determine the lateral variations of Ge composition within the undulated film. Additional FE modeling results indicated that such composition variations would contribute further overall stress reduction in the film. In-situ transmission electron microscopy (TEM) annealing experiments were performed to measure the dislocation propagation velocity in strained Si1-xGex films to explore the nanoscale correlations between stress variations and surface morphology. The local dislocation velocity data were translated into stresses using previously established stress-velocity relations developed for this system. The inferred stress variations correlated well spatially to the period of surface undulations. However, there was a large discrepancy in the stress variations between undulation peaks and troughs inferred from the local dislocation velocities compared to those calculated by FE models. A stress-dependent single-kink nucleation model was then successfully applied to reconcile these differences. The detailed local

  1. Demonstration of a high-field short-period superconducting helical undulator suitable for future TeV-scale linear collider positron sources.

    Science.gov (United States)

    Scott, D J; Clarke, J A; Baynham, D E; Bayliss, V; Bradshaw, T; Burton, G; Brummitt, A; Carr, S; Lintern, A; Rochford, J; Taylor, O; Ivanyushenkov, Y

    2011-10-21

    The first demonstration of a full-scale working undulator module suitable for future TeV-scale positron-electron linear collider positron sources is presented. Generating sufficient positrons is an important challenge for these colliders, and using polarized e(+) would enhance the machine's capabilities. In an undulator-based source polarized positrons are generated in a metallic target via pair production initiated by circularly polarized photons produced in a helical undulator. We show how the undulator design is developed by considering impedance effects on the electron beam, modeling and constructing short prototypes before the successful fabrication, and testing of a final module.

  2. Canted Undulator Upgrade for GeoSoilEnviroCARS Sector 13 at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Stephen

    2013-02-02

    Support for the beamline component of the canted undulator upgrade of Sector 13 (GeoSoilEnviroCARS; managed and operated by the University of Chicago) at the Advanced Photon Source (APS; Argonne National Laboratory) was received from three agencies (equally divided): NASA-SRLIDAP (now LARS), NSF-EAR-IF (ARRA) and DOE-Single Investigator Small Group (SISGR). The associated accelerator components (undulators, canted front end) were provided by the APS using DOE-ARRA funding. The intellectual merit of the research enabled by the upgrade lies in advancing our knowledge of the composition, structure and properties of earth materials; the processes they control; and the processes that produce them. The upgrade will facilitate scientific advances in the following areas: high pressure mineral physics and chemistry, non-crystalline and nano-crystalline materials at high pressure, chemistry of hydrothermal fluids, reactions at mineral-water interfaces, biogeochemistry, oxidation states of magmas, flow dynamics of fluids and solids, and cosmochemistry. The upgrade, allowing the microprobe to operate 100% of the time and the high pressure and surface scattering and spectroscopy instruments to receive beam time increases, will facilitate much more efficient use of the substantial investment in these instruments. The broad scientific community will benefit by the increase in the number of scientists who conduct cutting-edge research at GSECARS. The user program in stations 13ID-C (interface scattering) and 13ID-D (laser heated diamond anvil cell and large volume press) recommenced in June 2012. The operation of the 13ID-E microprobe station began in the Fall 2012 cycle (Oct.-Dec 2012). The upgraded canted beamlines double the amount of undulator beam time at Sector 13 and provide new capabilities including extended operations of the X-ray microprobe down to the sulfur K edge and enhanced brightness at high energy. The availability of the upgraded beamlines will advance the

  3. Emittance measurements of CESR using the emitted radiation from a short-period undulator

    International Nuclear Information System (INIS)

    The horizontal and vertical emittance of the Cornell Electron Storage Ring (CESR) was measured using the radiation emitted from a short-period (3.3 cm) 123-pole undulator. Average horizontal and vertical emittances measured by this technique were 80 nm-rad and 1.75 nm-rad, respectively. These compare favorably with the results from a charge-coupled device (CCD) system routinely used at CESR and with the calculated values of 65 nm-rad and ∼1 nm-rad for the horizontal and vertical emittances respectively

  4. Numerical modeling of shoreline undulations part 2: Varying wave climate and comparison with observations

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen

    2013-01-01

    waves with a directional spreading. In this paper, these findings are extended to firstly include the effect of a varying wave climate on the shoreline morphology and secondly, to tune the model to two naturally occurring shorelines. It is found that the effect of a variable wave climate is to slow down...... the development of the morphology and in some cases to inhibit the formation of shore-parallel spits at the crest of the undulations. On one of the natural shorelines, the west coast of Namibia, the shore is exposed to very obliquely waves from one main direction. Here, the shoreline model is able to...

  5. Controlling the morphology of carbon nanotube arrays: from spinnable forests to undulating foams

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying [Los Alamos National Laboratory; Zou, Guifu [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; Hawley, Marilyn E [Los Alamos National Laboratory; Sheehan, Chris J [Los Alamos National Laboratory; Zhu, Yuntain [Los Alamos National Laboratory; Jia, Quanxi [Los Alamos National Laboratory; Doorn, Stephen K [NCSU; Htoon, Han [NCSU

    2009-01-01

    By controlling catalyst pretreatment conditions, we demonstrate that the degree of spinnability of carbon nanotubes (CNTs) is closely related to the morphology of CNT arrays. Shortest catalyst pretreatment time led to CNT arrays with the best spinnability, while prolonged pretreatment resulted in coarsening of catalyst particles and non-spinnable CNTs. We further demonstrate the growth of undulating CNT arrays with uniform and tunable waviness by controlling the coalescence of catalyst particles. The CNT arrays can be tuned from well-aligned, spinnable forests to uniformly wavy, foam-like films by controlling catalyst pretreatment conditions.

  6. An acoustical research of the undulating wooden ceiling in the Vyborg Library

    DEFF Research Database (Denmark)

    Mortensen, Bo

    2004-01-01

    Much has been written about the Undulating Ceiling at the lecture hall of the Vyborg Library. Alvar Aalto himself claimed the ceiling to be "ninety-nine per cent acoustically perfect" and the sketches showing the acoustical considerations behind the ceiling-design is often reproduced. But how did...... it actually function? Did the wave form have the claimed acoustical avantages or could the ceiling as well have been horisontal. Comprehensive acoustical investigations have been carried out including acoustical measurements in a 1:20 scale model and calculations in a 3D computer model of the lecture...

  7. Undulant Universe

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela; /Valencia U.; Mena, Olga; Quigg, Chris; /Fermilab

    2004-12-01

    If the equation of state for ''dark energy'' varies periodically, the expansion of the Universe may have undergone alternating eras of acceleration and deceleration. We examine a specific form that survives existing observational tests, does not single out the present state of the Universe as exceptional, and suggests a future much like the matter-dominated past: a smooth expansion without a final inflationary epoch.

  8. Development of an electromagnetic phase shifter using a pair of cut-core coils for a cross undulator

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, I., E-mail: imatsuda@issp.u-tokyo.ac.jp [The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581 (Japan); Kuroda, A. [School of Science, University of Hyogo, Hyogo 651-2197 (Japan); Miyawaki, J.; Kosegawa, Y.; Yamamoto, S. [The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581 (Japan); Seike, T.; Bizen, T. [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Harada, Y. [The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581 (Japan); Tanaka, T.; Kitamura, H. [RIKEN SPring-8 Center, Hyogo 679-5148 (Japan)

    2014-12-11

    This paper describes the development of a phase shifter that can be used in cross undulators for fast polarization switching. The phase shifter is composed of a pair of cut-core coils and a thin-walled stainless steel duct. Evaluation of the magnetic fields of the phase shifter indicates that the switching frequency of this simple and low-cost device can exceed 30 Hz. - Highlights: • We have developed a simple phase shifter that can be used in a cross undulator for fast polarization switching. • The phase shifter is low-cost and it uses a pair of cut-core coil. • The polarization switching of the undulator light can exceed 30 Hz. • The phase shifter has the potential to make shot-by-shot polarization control for X-ray free electron laser.

  9. Combined electromagnetic and permanent magnet undulator to achieve higher field and easier field variation without mechanical movement

    Energy Technology Data Exchange (ETDEWEB)

    Bogachenkov, V.A.; Papadichev, V.A. [Lebedev Physical Institute, Moscow (Russian Federation)

    1995-12-31

    Hybrid or pure permanent magnet undulators (PMU) are widely used because they have high field quality, allow easy field correction and do not consume power. Their main drawback is the necessity of moving one half of the magnet relative to the other to change field value, which requires a high precision, remotely controlled (and thus costly) driving system On the other hand, electromagnetic undulatory (EMU) have no problem with field variation, but consume too much power (100 - 400 kW) for high fields. Adding permanent magnets to EMU results in a considerable decrease of power consumption, while retaining the advantage of easily changing field level. A model of a CW combined EM+PM plane undulator having a 4.8 cm period and 8 periods long is described. It is simple in design and cheap in manufacturing: magnet yokes are made of soft steel rings in which 1.6 cm air gaps were cut to form pole faces. Odd yokes are placed to one side of the undulator axis and even yokes to the other with the air gaps on the axis. Each set of yokes is excited by its own separate winding of simple racetrack shape. Undulator deflection parameter K = 1.1 (B = 2.4 kG) can be reached at a 0.78kW power level, i.e., less than 100 W per period, while without PM only a maximum K = 0.8 can be obtained and requires 4 kW power. No water cooling is needed, which greatly simplifies undulator design. The undulator was not optimized relative to the axial-air-gap to ring-width ratio: one might expect some increase in field level for thinner rings. Field amplitude depends also on relative transverse position of odd and even pole faces.

  10. NOVEL CHAMBER DESIGN FOR AN IN-VACUUM CRYO-COOLED MINI-GAP UNDULATOR

    International Nuclear Information System (INIS)

    A stainless steel, Ultra-High Vacuum (UHV) chamber, featuring a large vertical rectangular port (53''W by 16''H), has been fabricated to house the one-meter magnet assembly of a newly installed undulator insertion device for beamline X-25 at the National Synchrotron Light Source. To achieve UHV, the new chamber is equipped with a differential ion pump, NEG pump, nude ion gauge, residual gas analyzer, and an all metal roughing valve. Temperature of the magnet assembly is maintained below 90 C during vacuum bake. The large rectangular port cover is sealed to the main flange of the chamber using a one-piece flat aluminum gasket and special sealing surfaces developed exclusively by Nor-Cal Products, Inc. The large flange provides easy access to the gap of the installed magnet girders for in situ magnetic measurements and shimming. Special window ports were designed into the cover and chamber for manipulation of optical micrometers external to the chamber to provide precise measurements of the in-vacuum magnet gap. The vacuum chamber assembly features independently vacuum-isolated feedthroughs that can be used for either water-or-cryogenic refrigeration-cooling of the monolithic magnet girders. This would allow for cryogenic-cooled permanent magnet operation and has been successfully tested within temperature range of +100 C to -150 C. Details of the undulator assembly for beamline X-25 is described in the paper

  11. The NSLS X13 Mini-Gap Undulator: Design and Performance

    International Nuclear Information System (INIS)

    An in-vacuum short-period mini-gap undulator (MGU) has recently been installed within the National Synchrotron Light Source (NSLS) X13 straight-section. The MGU is a hybrid design, consisting of NdFeB permanent magnets and vanadium permendur poles. The MGU period is 1.25 cm, the overall length is 35 cm, and the gap can be varied between 3.3 and 11 mm. The higher magnetic field provided by the hybrid design supersedes that of the previous X13 undulator device (IVUN), allowing for a greater tunability. Operating down to a magnetic gap of 3.3 mm, the on-axis magnetic field is 0.92 Tesla, corresponding to a deflection parameter K∼1.07. The performance of the MGU has been measured using a single crystal spectrometer. At a gap of 3.3 mm, the MGU's fundamental energy was recorded at 3.7 keV with a brightness of 4x1017 ph/sec/mm2/mrad2/0.1%BW/300mA

  12. Effect of undulators on the stored electron beam of Indus-2

    Institute of Scientific and Technical Information of China (English)

    Abdurrahim; A.D.Ghodke

    2015-01-01

    Indus-2 is an Indian synchrotron light source,operating at 2.5 GeV and generating synchrotron radiation from its bending magnets.In order to provide more intense synchrotron radiation to the synchrotron users,there is a plan to install five insertion devices in the Indus-2 storage ring.In the first phase of installation of insertion devices,there is a proposal to install two out-vacuum pure permanent magnet linearly polarized undulators in long straight sections of the Indus-2 storage ring.The presence of the insertion devices in the ring has inevitable effects on beam parameters like betatron tune,betatron amplitude function,closed orbit,emittance,energy spread and dynamic aperture etc.In this paper,the effect of two undulators on the above mentioned parameters of the Indus-2 stored electron beam at 2.5 GeV is presented.Moreover a correction scheme for the restoration of the betatron tune and amplitude function is also presented.

  13. The onset of layer undulations in smectic A liquid crystals due to a strong magnetic field

    Science.gov (United States)

    Contreras, A.; Garcia-Azpeitia, C.; García-Cervera, C. J.; Joo, S.

    2016-08-01

    We investigate the effect of a strong magnetic field on a three dimensional smectic A liquid crystal. We identify a critical field above which the uniform layered state loses stability; this is associated to the onset of layer undulations. In a previous work García-Cervera and Joo (2012 Arch. Ration. Mech. Anal. 203 1-43), García-Cervera and Joo considered the two dimensional case and analyzed the transition to the undulated state via a simple bifurcation. In dimension n  =  3 the situation is more delicate because the first eigenvalue of the corresponding linearized problem is not simple. We overcome the difficulties inherent to this higher dimensional setting by identifying the irreducible representations for natural actions on the functional that take into account the invariances of the problem thus allowing for reducing the bifurcation analysis to a subspace with symmetries. We are able to describe at least two bifurcation branches, highlighting the richer landscape of energy critical states in the three dimensional setting. Finally, we analyze a reduced two dimensional problem, assuming the magnetic field is very strong, and are able to relate this to a model in micromagnetics studied in Alouges et al (2002 ESAIM Control Optim. Calc. Var. 8 31-68), from where we deduce the periodicity property of minimizers.

  14. Design, Implementation and Control of a Fish Robot with Undulating Fins

    Directory of Open Access Journals (Sweden)

    Mohsen Siahmansouri

    2011-11-01

    Full Text Available Biomimetic robots can potentially perform better than conventional robots in underwater vehicle designing. This paper describes the design of the propulsion system and depth control of a robotic fish. In this study, inspired by knife fish, we have designed and implemented an undulating fin to produce propulsive force. This undulating fin is a segmental anal fin that produces sinusoidal wave to propel the robot. The relationship between the individual fin segment and phase angles with the overall fin trajectory has also been discussed. This propulsive force can be adjusted and directed for fish robot manoeuvre by a mechanical system with two servomotors. These servomotors regulate the direction and depth of swimming. A wireless remote control system is designed to adjust the servomotors which enables us to control revolution, speed and phase differences of neighbor servomotors of fins. Finally, Field trials are conducted in an outdoor pool to demonstrate the relationship between robotic fish speed and fin parameters like phase difference, the number of phase and undulatory amplitude.

  15. The nuclear-resonance-scattering station at the PETRA II undulator beamline

    Energy Technology Data Exchange (ETDEWEB)

    Franz, H.; Hukelmann, B.; Schneider, J.R. [HASYLAB at DESY (Germany)

    2000-07-15

    PETRA II, a 12 GeV accelerator at DESY, Hamburg, is used to produce synchrotron radiation (SR) for experiments in the hard X-ray regime when it is not running as injector for HERA. The beam from an undulator is split by a diamond crystal in Laue geometry to feed two experimental stations, one of which is now dedicated for nuclear resonance experiments. The X-ray energy may be chosen in the range from 5 to 55 keV covering all isotopes already observed with SR and many interesting candidates for new resonances. Tuning may be performed by optimising the magnetic gap and the storage ring energy. In particular, the opportunities for timing experiments are unique due to a very flexible filling mode of the storage ring. The flux at the sample position is comparable to undulator beams at ESRF. The second beamline covers higher energies up to some 300 keV and may also be used for nuclear resonance experiments.

  16. The nuclear-resonance-scattering station at the PETRA II undulator beamline

    Science.gov (United States)

    Franz, H.; Hukelmann, B.; Schneider, J. R.

    2000-07-01

    PETRA II, a 12 GeV accelerator at DESY, Hamburg, is used to produce synchrotron radiation (SR) for experiments in the hard X-ray regime when it is not running as injector for HERA. The beam from an undulator is split by a diamond crystal in Laue geometry to feed two experimental stations, one of which is now dedicated for nuclear resonance experiments. The X-ray energy may be chosen in the range from 5 to 55 keV covering all isotopes already observed with SR and many interesting candidates for new resonances. Tuning may be performed by optimising the magnetic gap and the storage ring energy. In particular, the opportunities for timing experiments are unique due to a very flexible filling mode of the storage ring. The flux at the sample position is comparable to undulator beams at ESRF. The second beamline covers higher energies up to some 300 keV and may also be used for nuclear resonance experiments.

  17. Quadrupole Magnet Error Sensitivities for FODO-Cell and Triplet Lattices in the LCLS Undulator

    International Nuclear Information System (INIS)

    The error sensitivities of quadrupole magnets in the LCLS FEL undulator are compared for a FODO-cell lattice and for a triplet lattice. The comparisons are made at a radiation wavelength of 1.5 (angstrom), where electron-to-photon phase errors are very sensitive to small trajectory variations in misaligned quadrupoles between the undulator sections. The results show that the triplet lattice is extremely sensitive, with triplet pitch and yaw alignment tolerances of ∼100 (micro)rad. The FODO-cell lattice, with its shorter, weaker quadrupoles is much more error tolerant with pitch and yaw tolerances of ∼2.5 mrad. Several other magnet errors are examined and categorized as trajectory, phase slip, and beam size effects. In nearly all cases, the FODO-cell lattice is much less sensitive with technologically achievable tolerance levels, while the triplet lattice tolerances are, in many cases, near achievable limits and may not be sustainable over the long term. Table 2 presents a brief tolerance comparison for the two lattice types

  18. X1A: Second-generation undulator beamlines serving soft x-ray spectromicroscopy experiments at the NSLS

    International Nuclear Information System (INIS)

    The X1A undulator beamline is being rebuilt with two separate monochromators on its two branches. The new arrangement will deliver spatially coherent beams to imaging experiments, with spectral resolving power of up to 5000, and the capability to optimize the resolving power versus flux. The beamlines will operate simultaneously, and each will use 15 percent of the undulator beam, yet deliver high coherent flux. Because of the small beam divergence, the spherical grating monochromators can operate with fixed exit arms throughout the 250 endash 800 eV range. copyright 1996 American Institute of Physics

  19. The BTFEL, an infrared free-electron laser amplifier based on a new-design short-period superconducting tape undulator

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, M., E-mail: moohyun@postech.edu [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, Postech, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Filippetto, D.; Papadopoulos, C.F. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Pellegrini, C. [Department of Physics, University of California, Los Angeles, CA 90095 (United States); Penn, G.; Prestemon, S. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Sannibale, F., E-mail: fsannibale@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2011-12-21

    The development of undulator technologies capable of generating sub-cm undulator periods is assuming an increasing importance in X-ray free electron laser (FEL) applications. Indeed, such devices jointly with the high brightness electron beams already demonstrated at operating facilities would allow for lower energy, more compact electron linacs with a beneficial impact on the size and cost of X-ray FEL facilities. A novel design super-conducting undulator is being developed at the Lawrence Berkeley National Laboratory (LBNL) with the potential of sub-cm periods with reasonably large undulator parameter and gap. The potential and capability of such undulator technology need to be experimentally demonstrated. In this paper, the possibility of constructing an infrared FEL by combining the new undulator with the high brightness beam from the APEX injector facility at LBNL is investigated. Calculations show that the resulting FEL, when operated in self-amplified-spontaneous-emission mode, is expected to deliver a saturated power of almost a MW within a {approx}4m undulator length, in a single-spike of coherent radiation at {approx}2{mu}m wavelength. It will be also shown that the small-period of the undulator associated with the relatively low energy of the APEX beam, forces the FEL to operate in a regime with unusual and interesting characteristics. The alternative option of laser seeding the FEL is also briefly examined, showing the potential to reduce the saturation length even further.

  20. Center for X-Ray Optics, 1986

    International Nuclear Information System (INIS)

    The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers

  1. Radiological considerations in the operation of the low-energy undulator test line (LEUTL).

    Energy Technology Data Exchange (ETDEWEB)

    Moe, H.J.

    1998-11-11

    The Low-Energy Undulator Test Line (LEUTL) is a facility that uses the existing APS linac to accelerate electrons up to an energy of 700 MeV. These electrons are transported through the Pm into a portion of the booster synchrotrons and on into the LEUTL main enclosure (MIL 97). Figure 1 shows the layout of the LEUTL building, which consists of an earth-benned concrete enclosure and an end-station building. The concrete enclosure houses the electron beamline, test undulator, and beam dump. This facility is about 51 m long and 3.66 m wide. Technical components and diagnostics for characterizing the undulator light are found in the end station. This building has about 111 m{sup 2} of floor space. This note deals with the radiological considerations of operations using electrons up to 700 MeV and at power levels up to the safety envelope of 1 kW. Previous radiological considerations for electron and positron operations in the linac, PAR, and synchrotrons have been addressed else-where (MOE 93a, 93b, and 93c). Much of the methodology discussed in the previous writeups, as well as in MOE 94, has been used in the computations in this note. The radiological aspects that are addressed include the following: prompt secondary radiation (bremsstrahlung, giant resonance neutrons, medium- and high-energy neutrons) produced by electrons interacting in a beam stop or in component structures; skyshine radiation, which produces a radiation field in nearby areas and at the nearest off-site location; radioactive gases produced by neutron irradiation of air in the vicinity of a particle loss site; noxious gases (ozone and others) produced in air by the escaping bremsstrahlung radiation that results from absorbing particles in the components; activation of the LEUTL components that results in a residual radiation field in the vicinity of these materials following shutdown; potential activation of water used for cooling the magnets and other purposes in the tunnel; and evaluation of the

  2. A Comparative Numerical Study on the Performances and Vortical Patterns of Two Bioinspired Oscillatory Mechanisms: Undulating and Pure Heaving.

    Science.gov (United States)

    Ebrahimi, Mohsen; Abbaspour, Madjid

    2015-01-01

    The hydrodynamics and energetics of bioinspired oscillating mechanisms have received significant attentions by engineers and biologists to develop the underwater and air vehicles. Undulating and pure heaving (or plunging) motions are two significant mechanisms which are utilized in nature to provide propulsive, maneuvering, and stabilization forces. This study aims to elucidate and compare the propulsive vortical signature and performance of these two important natural mechanisms through a systematic numerical study. Navier-Stokes equations are solved, by a pressure-based finite volume method solver, in an arbitrary Lagrangian-Eulerian (ALE) framework domain containing a 2D NACA0012 foil moving with prescribed kinematics. Some of the important findings are (1) the thrust production of the heaving foil begins at lower St and has a greater growing slope with respect to the St; (2) the undulating mechanism has some limitations to produce high thrust forces; (3) the undulating foil shows a lower power consumption and higher efficiency; (4) changing the Reynolds number (Re) in a constant St affects the performance of the oscillations; and (5) there is a distinguishable appearance of leading edge vortices in the wake of the heaving foil without observable ones in the wake of the undulating foil, especially at higher St. PMID:27057133

  3. Purified SASE undulator configuration to enhance the performance of the soft x-ray beamline at the European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni; Zagorodnov, Igor [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany)

    2013-08-15

    The purified SASE (pSASE) undulator configuration recently proposed at SLAC promises an increase in the output spectral density of XFELs. In this article we study a straightforward implementation of this configuration for the soft x-ray beamline at the European XFEL. A few undulator cells, resonant at a subharmonic of the FEL radiation, are used in the middle of the exponential regime to amplify the radiation, while simultaneously reducing the FEL bandwidth. Based on start-to-end simulations, we show that with the proposed configuration the spectral density in the photon energy range between 1.3 keV and 3 keV can be enhanced of an order of magnitude compared to the baseline mode of operation. This option can be implemented into the tunable-gap SASE3 baseline undulator without additional hardware, and it is complementary to the self-seeding option with grating monochromator proposed for the same undulator line, which can cover the photon energy range between about 0.26 keV and 1 keV.

  4. A table-top x-ray FEL based on a laser wakefield accelerator-undulator system

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, K.; Kawakubo, T.; Nakanishi, H. [National Lab. for High Energy Physics, Ibaraki-ken (Japan)] [and others

    1995-12-31

    Ultrahigh-gradient electron acceleration has been confirmed owing to the laser wakefield acceleration mechanism driven by an intense short laser wakefield acceleration mechanism driven by an intense short laser pulse in an underdense plasma. The laser wakefield acceleration makes it possible to build a compact electron linac capable of producing an ultra-short bunched electron beam. While the accelerator is attributed to longitudinal wakefields, transverse wakefields simultaneously generated by a short laser pulse can serve as a plasma undulator with a very short wavelength equal to a half of the plasma wavelength. We propose a new FEL concept for X-rays based on a laser wakefield accelerator-undulator system driven by intense short laser pulses delivered from table-top terawatt lasers. The system is composed of the accelerator stage and the undulator stage in a table-top size. A low energy electron beam is accelerated an bunched into microbunches due to laser wakefields in the accelerator stage. A micro-bunched beam travelling to the opposite direction of driving laser pulses produces coherent X-ray radiation in the undulator stage. A practical configuration and its analyses are presented.

  5. Observation and analysis of self-amplified spontaneous emission at the APS low-energy undulator test line

    CERN Document Server

    Arnold, N D; Banks, G; Bechtold, R; Beczek, K; Benson, C; Berg, S; Berg, W; Biedron, S G; Biggs, J A; Boerste, K; Borland, M; Bosek, M; Brzowski, W R; Budz, J; Carwardine, J A; Castro, P; Chae, Y C; Christensen, S; Clark, C; Conde, M; Crosbie, E A; Decker, G A; Dejus, Roger J; Deleon, H; Den Hartog, P K; Deriy, B N; Dohan, D; Dombrowski, P; Donkers, D; Doose, C L; Dortwegt, R J; Edwards, G A; Eidelman, Y; Erdmann, M J; Error, J J; Ferry, R; Flood, R; Forrestal, J; Freund, H; Friedsam, H; Gagliano, J; Gai, W; Galayda, J N; Gerig, R; Gilmore, R L; Gluskin, E; Goeppner, G A; Goetzen, J; Gold, C; Grelick, A E; Hahne, M W; Hanuska, S; Harkay, K C; Harris, G; Hillman, A L; Hogrefe, R; Hoyt, J; Huang, Z; Jagger, J M; Jansma, W G; Jaski, M; Jones, S J; Keane, R T; Kelly, A L; Keyser, C; Kim, K J; Kim, S H; Kirshenbaum, M; Klick, J H; Knoerzer, K; Knott, M; Koldenhoven, R J; Labuda, S; Laird, R; Lang, J; Lenkszus, F R; Lessner, E S; Lewellen, J W; Li, Y; Lill, R M; Lumpkin, Alex H; Makarov, O A; Markovich, G M; McDowell, M; McDowell, W P; McNamara, P E; Meier, T; Meyer, D; Michalek, W; Milton, S V; Moe, H; Moog, E; Morrison, L; Nassiri, A; Noonan, J R; Otto, R; Pace, J; Pasky, S J; Penicka, J M; Pietryla, A F; Pile, G; Pitts, C; Power, J; Powers, T; Putnam, C C; Puttkammer, A J; Reigle, D; Reigle, L; Ronzhin, D; Rotela, E R; Russell, E F; Sajaev, Vadim; Sarkar, S; Scapino, J C; Schröder, K; Seglem, R A; Sereno, N S; Sharma, S K; Sidarous, J F; Singh, O; Smith, T L; Soliday, R; Sprau, G A; Stein, S J; Stejskal, B; Svirtun, V; Teng, L C; Theres, E; Thompson, K; Tieman, B J; Torres, J A; Trakhtenberg, E; Travish, G; Trento, G F; Vacca, J; Vasserman, I B; Vinokurov, N A; Walters, D R; Wang, J; Wang, X J; Warren, J; Wesling, S; Weyer, D L; Wiemerslage, G; Wilhelmi, K; Wright, R; Wyncott, D; Xu, S; Yang, B X; Yoder, W; Zabel, R B

    2001-01-01

    Exponential growth of self-amplified spontaneous emission at 530 nm was first experimentally observed at the Advanced Photon Source low-energy undulator test line in December 1999. Since then, further detailed measurements and analysis of the results have been made. Here, we present the measurements and compare these with calculations based on measured electron beam properties and theoretical expectations.

  6. Observation and analysis of self-amplified spontaneous emission at the APS low-energy undulator test line

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, N.D.; Attig, J.; Banks, G.; Bechtold, R.; Beczek, K.; Benson, C.; Berg, S.; Berg, W.; Biedron, S.G.; Biggs, J.A.; Borland, M.; Boerste, K.; Bosek, M.; Brzowski, W.R.; Budz, J.; Carwardine, J.A.; Castro, P.; Chae, Y.-C.; Christensen, S.; Clark, C.; Conde, M.; Crosbie, E.A.; Decker, G.A.; Dejus, R.J.; DeLeon, H.; Den Hartog, P.K.; Deriy, B.N.; Dohan, D.; Dombrowski, P.; Donkers, D.; Doose, C.L.; Dortwegt, R.J.; Edwards, G.A.; Eidelman, Y.; Erdmann, M.J.; Error, J.; Ferry, R.; Flood, R.; Forrestal, J.; Freund, H.; Friedsam, H.; Gagliano, J.; Gai, W.; Galayda, J.N.; Gerig, R.; Gilmore, R.L.; Gluskin, E.; Goeppner, G.A.; Goetzen, J.; Gold, C.; Gorski, A.J.; Grelick, A.E.; Hahne, M.W.; Hanuska, S.; Harkay, K.C.; Harris, G.; Hillman, A.L.; Hogrefe, R.; Hoyt, J.; Huang, Z.; Jagger, J.M.; Jansma, W.G.; Jaski, M.; Jones, S.J.; Keane, R.T.; Kelly, A.L.; Keyser, C.; Kim, K.-J.K.-J.; Kim, S.H.; Kirshenbaum, M.; Klick, J.H.; Knoerzer, K.; Koldenhoven, R.J.; Knott, M.; Labuda, S.; Laird, R.; Lang, J.; Lenkszus, F.; Lessner, E.S.; Lewellen, J.W.; Li, Y.; Lill, R.M.; Lumpkin, A.H.; Makarov, O.A.; Markovich, G.M.; McDowell, M.; McDowell, W.P.; McNamara, P.E.; Meier, T.; Meyer, D.; Michalek, W.; Milton, S.V. E-mail: milton@aps.anl.gov; Moe, H.; Moog, E.R.; Morrison, L.; Nassiri, A.; Noonan, J.R.; Otto, R.; Pace, J.; Pasky, S.J.; Penicka, J.M.; Pietryla, A.F.; Pile, G.; Pitts, C.; Power, J.; Powers, T.; Putnam, C.C.; Puttkammer, A.J.; Reigle, D.; Reigle, L.; Ronzhin, D.; Rotela, E.R.; Russell, E.F.; Sajaev, V.; Sarkar, S.; Scapino, J.C.; Schroeder, K.; Seglem, R.A.; Sereno, N.S.; Sharma, S.K.; Sidarous, J.F.; Singh, O.; Smith, T.L.; Soliday, R.; Sprau, G.A.; Stein, S.J.; Stejskal, B.; Svirtun, V.; Teng, L.C.; Theres, E.; Thompson, K.; Tieman, B.J.; Torres, J.A.; Trakhtenberg, E.M.; Travish, G.; Trento, G.F.; Vacca, J.; Vasserman, I.B.; Vinokurov, N.A.; Walters, D.R.; Wang, J.; Wang, X.J.; Warren, J.; Wesling, S.; Weyer, D.L.; Wiemerslage, G.; Wilhelmi, K.; Wright, R.

    2001-12-21

    Exponential growth of self-amplified spontaneous emission at 530 nm was first experimentally observed at the Advanced Photon Source low-energy undulator test line in December 1999. Since then, further detailed measurements and analysis of the results have been made. Here, we present the measurements and compare these with calculations based on measured electron beam properties and theoretical expectations.

  7. Evaluating the Fin-ray Trajectory Tracking of Bio-inspired Robotic Undulating Fins via an Experimental-numerical Approach

    Directory of Open Access Journals (Sweden)

    Xiaojia Xiang

    2014-07-01

    Full Text Available In the past decade, biomimetic undulating fin propulsion has been one of the main topics considered by scientists and researchers in the field of robotic fish. This technology is inspired by the biological wave-like propulsion of ribbon-finned fish. The swimming modes have aquatic application potentials with greater manoeuvrability, less detectable noise or wake and better efficiency at low speeds. The present work concentrates on the evaluation of fin-ray trajectory tracking of biorobotic undulating fins at the levels of kinematics and hydrodynamics by using an experimental-numerical approach. Firstly, fin-ray tracking inconsistence between the desired and actual undulating trajectories is embodied with experimental data of the fin prototype. Next, the dynamics' nonlinearity is numerically and analytically unveiled by using the computational fluid dynamics (CFD method, from the viewpoint of vortex shedding and the hydro-effect. The evaluation of fin-ray tracking performance creates a good basis for control design to improve the fin-ray undulation of prototypes.

  8. A Comparative Numerical Study on the Performances and Vortical Patterns of Two Bioinspired Oscillatory Mechanisms: Undulating and Pure Heaving.

    Science.gov (United States)

    Ebrahimi, Mohsen; Abbaspour, Madjid

    2015-01-01

    The hydrodynamics and energetics of bioinspired oscillating mechanisms have received significant attentions by engineers and biologists to develop the underwater and air vehicles. Undulating and pure heaving (or plunging) motions are two significant mechanisms which are utilized in nature to provide propulsive, maneuvering, and stabilization forces. This study aims to elucidate and compare the propulsive vortical signature and performance of these two important natural mechanisms through a systematic numerical study. Navier-Stokes equations are solved, by a pressure-based finite volume method solver, in an arbitrary Lagrangian-Eulerian (ALE) framework domain containing a 2D NACA0012 foil moving with prescribed kinematics. Some of the important findings are (1) the thrust production of the heaving foil begins at lower St and has a greater growing slope with respect to the St; (2) the undulating mechanism has some limitations to produce high thrust forces; (3) the undulating foil shows a lower power consumption and higher efficiency; (4) changing the Reynolds number (Re) in a constant St affects the performance of the oscillations; and (5) there is a distinguishable appearance of leading edge vortices in the wake of the heaving foil without observable ones in the wake of the undulating foil, especially at higher St.

  9. Towards an exact relativistic theory of Earth's geoid undulation

    Energy Technology Data Exchange (ETDEWEB)

    Kopeikin, Sergei M., E-mail: kopeikins@missouri.edu [Department of Physics & Astronomy, University of Missouri, Columbia, MO 65211 (United States); Siberian State Geodetic Academy, 10 Plakhotny St., Novosibirsk 630108 (Russian Federation); Mazurova, Elena M., E-mail: e_mazurova@mail.ru [Moscow State University of Geodesy and Cartography, 4 Gorokhovsky Alley, Moscow 105064 (Russian Federation); Siberian State Geodetic Academy, 10 Plakhotny St., Novosibirsk 630108 (Russian Federation); Karpik, Alexander P., E-mail: rector@ssga.ru [Siberian State Geodetic Academy, 10 Plakhotny St., Novosibirsk 630108 (Russian Federation)

    2015-08-14

    The present paper extends the Newtonian concept of the geoid in classic geodesy towards the realm of general relativity by utilizing the covariant geometric methods of the perturbation theory of curved manifolds. It yields a covariant definition of the anomalous (disturbing) gravity potential and formulates differential equation for it in the form of a covariant Laplace equation. The paper also derives the Bruns equation for calculation of geoid's height with full account for relativistic effects beyond the Newtonian approximation. A brief discussion of the relativistic Bruns formula is provided. - Highlights: • We apply general relativity to define the exact concept of relativistic geoid. • We derive relativistic equation of geoid and the reference level surface. • We employ the manifold perturbation theory to discuss geoid's undulation.

  10. A Study on Inviscid Flow with a Free Surface over an Undulating Bottom

    Directory of Open Access Journals (Sweden)

    Srikumar Panda

    2016-01-01

    Full Text Available In this paper, the problem involving inviscid flow with a free surface over an undulating bottom is studied within the framework of linear theory. Applying perturbation analysis in conjunction with the Fourier transform technique, the boundary value problem arising from the flow problem is solved analytically. Behaviour of both interface and free-surface profiles, which are unknown at the outset, are analyzed. It is found that each profile (interface and free-surface possesses a wave free region at the far upstream, followed by a modulated downstream wave. It also observed, for the first time, that the amplitude of the downstream wave is varying. Further, the effects of various system parameters are analyzed and demonstrated in graphical forms.

  11. A compact tunable polarized X-ray source based on laser-plasma helical undulators

    CERN Document Server

    Luo, Ji; Zeng, Ming; Vieira, Jorge; Yu, Lu-Le; Weng, Su-Ming; Silva, Luis O; Jaroszynski, Dino A; Sheng, Zheng-Ming; Zhang, Jie

    2016-01-01

    Laser wakefield accelerators have great potential as the basis for next generation compact radiation sources because their accelerating gradients are three orders of magnitude larger than traditional accelerators. However, X-ray radiation from such devices still lacks of tunability, especially the intensity and polarization distribution. Here we propose a tunable polarized radiation source from a helical plasma undulator based on plasma channel guided wakefield accelerator. When a laser pulse is initially incident with a skew angle relative to the channel axis, the laser and accelerated electrons experience collective spiral motions, which leads to elliptically polarized synchrotron-like radiation with flexible tunability on radiation intensity, spectra and polarization. We demonstrate that a radiation source with millimeter size and peak brilliance of $2\\times10^{19} photons/s/mm^{2}/mrad^{2}/0.1%$ bandwidth can be made with moderate laser and electron beam parameters. This brilliance is comparable with the ...

  12. Scattering of interface wave by bottom undulations in the presence of thin submerged vertical wall with a gap

    Science.gov (United States)

    Dolai, P.

    2016-05-01

    In this paper, the problem of interface wave scattering by bottom undulations in the presence of a thin submerged vertical wall with a gap is investigated. The thin vertical wall with a gap is submerged in a lower fluid of finite depth with bottom undulations and the upper fluid is of infinite height separated by a common interface. In the method of solution, we use a simplified perturbation analysis and suitable applications of Green's integral theorem in the two fluid regions produce first-order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom undulations and solution of the scattering problem involving a submerged vertical wall present in the lower fluid of uniform finite depth. For sinusoidal bottom undulations, the first-order transmission coefficient vanishes identically. The corresponding first-order reflection coefficient is computed numerically by solving the zero-order reflection coefficient and a suitable application of multi-term Galerkin approximations. The numerical results of the zero-order and first-order reflection coefficients are depicted graphically against the wave number in a number of figures. An oscillatory nature is observed of first-order reflection coefficient due to multiple interactions of the incident wave with bottom undulations, the edges of the submerged wall and the interface. The first-order reflection coefficient has a peak value for some particular value of the ratio of the incident wavelength and the bottom wavelength. The presence of the upper fluid has some significant effect on the reflection coefficients.

  13. Present status of vacuum ultraviolet natural circular dichroism measurement system using polarizing undulator at TERAS BL5 beamline

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahito, E-mail: masahito-tanaka@aist.go.j [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 (Japan); Yagi-Watanabe, Kazutoshi; Kaneko, Fusae [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 (Japan); Nakagawa, Kazumichi [Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan)

    2010-08-15

    The study of natural circular dichroism (CD) in the vacuum and extreme ultraviolet (VUV and EUV) regions has been providing us with chirality and structural information on biomolecules. We have developed the beamline BL5 at TERAS, Tsukuba, which is equipped with a compact Onuki-type polarizing undulator. This beamline is dedicated to measuring the CD spectra in the VUV and EUV regions for the photon energy region of 5-40 eV. The use of a polarization modulation technique with a polarizing undulator is essential for detecting a weak CD signal. Using this CD system, the natural CD spectrum has been measured in the EUV region up to 40 eV for the first time. In addition, the differences and the similarities between the CD spectra of four amino acid films (alanine, valine, leucine, and phenylalanine) in the VUV region up to 9.5 eV are determined.

  14. Procurement history of the hybrid undulator for the U-5 beam line at the national synchrotron light source

    International Nuclear Information System (INIS)

    As part of a national multi-institutional Materials Research Group (MRG), Argonne National Laboratory had the responsibility, under a prime contract with the US Department of Energy, of obtaining a Permanent Magnet Hybrid undulator to be used on the U5 Beam Line on the VUV Ring at the National Synchrotron Light Source (NSLS). The procurement involved determining the technical specifications of the device as well as developing an effective procedure for evaluation of the proposals. The conceptual-design of the magnetic structure including all pertinent magnetic field properties was developed before the actual procurement process was initiated. In addition, complete calculations of the expected spectral properties of the undulator were performed which included the emittance properties of the VUV ring. The results from both analysis were essential in determining the expected performance of the device and the final choice of operating parameters

  15. High-field strong-focusing undulator designs for X-ray Linac Coherent Light Source (LCLS) applications

    International Nuclear Information System (INIS)

    Linac-driven X-Ray Free Electron Lasers (e.g., Linac Coherent Light Sources (LCLSs)), operating on the principle of single-pass saturation in the Self-Amplified Spontaneous Emission (SASE) regime typically require multi-GeV beam energies and undulator lengths in excess of tens of meters to attain sufficient gain in the 1 angstrom--0.1 angstrom range. In this parameter regime, the undulator structure must provide: (1) field amplitudes B0 in excess of 1T within periods of 4cm or less, (2) peak on-axis focusing gradients on the order of 30T/m, and (3) field quality in the 0.1%--0.3% range. In this paper the authors report on designs under consideration for a 4.5--1.5 angstrom LCLS based on superconducting (SC), hybrid/PM, and pulsed-Cu technologies

  16. Construction of the undulator beamline equipped with a UHV-STM for observations of synchrotron-radiation-stimulated surface reaction

    International Nuclear Information System (INIS)

    An undulator beamline equipped with a UHV-scanning tunneling electron microscopy (STM) system has been designed and constructed at the UVSOR facility to investigate synchrotron-radiation-stimulated reactions. Using this undulator beamline, we have observed irradiation effects on the hydrogen terminated-(H-) Si(1 1 1) surfaces in atomic scale. The small protrusions, which are assigned to the rest-atom with missing H, appeared on the monohydride surface after irradiation. The density of them monotonically increased with irradiation dose. This phenomenon has been observed almost independent on the Si 2p core electron excitation threshold, indicating the significant contribution of the valence electron excitations to the Si-H bond dissociations

  17. Sm2Co17 magnet blocks for the in-vacuum undulators (IVU20) at the SSRF

    Institute of Scientific and Technical Information of China (English)

    HE Yong-Zhou; ZHOU Qiao-Gen; ZHANG Ji-Dong

    2011-01-01

    The design and development status of SmCo magnet blocks for two in-vacuum undulators (IVU20) at the SSRF with the same hybrid design has been described. By the technological improvement of some processes and comparison with the experimental SmCo magnet blocks for the IVU25A, magnetic properties such as the intrinsic coercive force H and the average magnetic moment M are increased, the bend point magnetic field H value and pass rate are significantly increased, and the magnetic field uniformity of the magnet blocks are significantly improved. The basic developmental method of high uniformity SmCo magnet blocks for IVU20 is presented. The magnetic field qualities of the magnet blocks, including the magnetic property, the magnetic moment distribution, the magnetization deviation angle and the magnetic field uniformity, basically satisfy the specifications of the two IVU20 in-vacuum undulators.

  18. Undulator-Based Production of Polarized Positrons, A Proposal for the 50-GeV Beam in the FFTB

    Energy Technology Data Exchange (ETDEWEB)

    G. Alexander; P. Anthony; V. Bharadwaj; Yu.K. Batygin; T. Behnke; S. Berridge; G.R. Bower; W. Bugg; R. Carr; E. Chudakov; J.E. Clendenin; F.J. Decker; Yu. Efremenko; T. Fieguth; K. Flottmann; M. Fukuda; V. Gharibyan; T. Handler; T. Hirose; R.H. Iverson; Yu. Kamyshkov; H. Kolanoski; T. Lohse; Chang-guo Lu; K.T. McDonald; N. Meyners; R. Michaels; A.A. Mikhailichenko; K. Monig; G. Moortgat-Pick; M. Olson; T. Omori; D. Onoprienko; N. Pavel; R. Pitthan; M. Purohit; L. Rinolfi; K.P. Schuler; J.C. Sheppard; S. Spanier; A. Stahl; Z.M. Szalata; J. Turner; D. Walz; A. Weidemann; J. Weisend

    2003-06-01

    The full exploitation of the physics potential of future linear colliders such as the JLC, NLC, and TESLA will require the development of polarized positron beams. In the proposed scheme of Balakin and Mikhailichenko [1] a helical undulator is employed to generate photons of several MeV with circular polarization which are then converted in a relatively thin target to generate longitudinally polarized positrons. This experiment, E-166, proposes to test this scheme to determine whether such a technique can produce polarized positron beams of sufficient quality for use in future linear colliders. The experiment will install a meter-long, short-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) at SLAC. A low-emittance 50-GeV electron beam passing through this undulator will generate circularly polarized photons with energies up to 10 MeV. These polarized photons are then converted to polarized positrons via pair production in thin targets. Titanium and tungsten targets, which are both candidates for use in linear colliders, will be tested. The experiment will measure the flux and polarization of the undulator photons, and the spectrum and polarization of the positrons produced in the conversion target, and compare the measurement results to simulations. Thus the proposed experiment directly tests for the first time the validity of the simulation programs used for the physics of polarized pair production in finite matter, in particular the effects of multiple scattering on polarization. Successful comparison of the experimental results to the simulations will lead to greater confidence in the proposed designs of polarized positrons sources for the next generation of linear colliders. This experiment requests six-weeks of time in the FFTB beam line: three weeks for installation and setup and three weeks of beam for data taking. A 50-GeV beam with about twice the SLC emittance at a repetition rate of 30 Hz is required.

  19. Three-dimensional numerical simulation of hydrodynamic interactions between pectoral-fin vortices and body undulation in a swimming fish

    Science.gov (United States)

    Yu, Cheng-Lun; Ting, Shang-Chieh; Yeh, Meng-Kao; Yang, Jing-Tang

    2011-09-01

    We investigated numerically the hydrodynamic interactions between pectoral-fin vortices and body undulation in a fish swimming with carangiform locomotion at a Reynolds number of 3.3 × 104; the three-dimensional, viscous, incompressible, Navier-Stokes equations were solved with a finite-volume method. For a fish swimming with the pectoral fins abducted, we characterized the wake flow structures, forces, and power consumption with respect to various Strouhal numbers. The numerical results reveal that a pair of vortices is formed immediately behind the abducted pectoral fins of a swimming fish. There exist hydrodynamic interactions between the pectoral-fin vortices and the undulating fish body. For Strouhal numbers in a range 0.2-0.8, the body undulation impedes the shedding of pectoral-fin vortices, resulting in vortices closely attached to the pectoral fins. In contrast, for Strouhal number = 0.1, the pectoral-fin vortices are shed from the pectoral fins and drift downstream. The low-pressure suction forces arising from the shed pectoral-fin vortices facilitate lateral movements of the fish body, decreasing the power consumption. This phenomenon indicates the possibility for an actual fish to harvest energy from the shed pectoral-fin vortices.

  20. Surface-micromachined magnetic undulator with period length between 10μm and 1 mm for advanced light sources

    Science.gov (United States)

    Harrison, Jere; Joshi, Abhijeet; Lake, Jonathan; Candler, Rob; Musumeci, Pietro

    2012-07-01

    A technological gap exists between the μm-scale wiggling periods achieved using electromagnetic waves of high intensity laser pulses and the mm scale of permanent-magnet and superconducting undulators. In the sub-mm range, surface-micromachined soft-magnetic micro-electro-mechanical system inductors with integrated solenoidal coils have already experimentally demonstrated 100 to 500 mT field amplitude across air gaps as large as 15μm. Simulations indicate that magnetic fields as large as 1.5 T across 50μm inductor gaps are feasible. A simple rearranging of the yoke and pole geometry allows for fabrication of 10+ cm long undulator structures with period lengths between 12.5μm and 1 mm. Such undulators find application both in high average power spontaneous emission sources and, if used in combination with ultrahigh-brightness electron beams, could lead to the realization of low energy compact free-electron lasers. Challenges include electron energy broadening due to wakefields and Joule heating in the electromagnet.

  1. Fiber diffraction using the BioCAT undulator beamline at the Advanced Photon Source

    CERN Document Server

    Irving, T C; Rosenbaum, G; Bunker, G B

    2000-01-01

    The BioCAT undulator-based beamline at the Advanced Photon Source, Argonne IL, USA is designed to be a state-of-the-art instrument for biological non-crystalline diffraction and X-ray absorption spectroscopy. The optics consist of double crystal monochromators with sagitally focussing second crystals followed by a vertically focussing mirror which allow independent focussing of the beam in the vertical and horizontal directions virtually anywhere along the length of the 12 m experimental enclosure. When configured for a 2 m fiber diffraction camera, a focal spot of less than 40x200 mu m (FWHM) has been observed which contained essentially all of the 1.5-2.5x10 sup 1 sup 3 ph/s delivered by the cryogenically-cooled Si(1 1 1) double crystal monochromator. This combination of highly demagnifying optics and the very low divergence of the very small source have yielded excellent quality patterns from various muscle specimens and collagen-containing tissues. Detectors available include a Fuji BAS2500 image plate sc...

  2. Present status of laser undulator compact X-ray source (LUCX) (7)

    International Nuclear Information System (INIS)

    We have developed a compact X-ray source via inverse Compton scattering between a multi-bunch electron beam and a laser pulse stacked in an optical cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. Our aim is to obtain a clear X-ray image in a shorter period of times in this accelerator, which consists of a 3.6 cell photo-cathode rf-gun, a 12cell standing wave accelerating structure and a 4-mirror planar optical cavity. In 2012, we have upgraded the accelerator to increase the intensity of X-ray. The expected number of X-ray after upgrade is 1.7x107 photons/pulse with 10% bandwidth. To achieve this target, it is necessary to increase the intensity of an electron beam to 500nC/pulse with 1000 bunches at 30 MeV. We have continued the multi-bunch beam generation and X-ray imaging test after upgrade. The accelerator produces 24 MeV beam with the total charge of 460nC in 800 bunches per pulse now. The aging process is also continued to increase energy and intensity. In this paper, the present status and the results of beam tuning and X-ray generation of LUCX accelerator will be reported. (author)

  3. Present status of laser undulator compact X-ray source (LUCX) (6)

    International Nuclear Information System (INIS)

    We have developed a compact X-ray source via inverse Compton scattering between multi-bunch electron beam and a laser pulse stacked in an optical cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. Since the autumn of 2011, we have begun X-ray imaging test. In the beginning, it had taken two hours to get an X-ray image because of low intensity of X-ray with 104 photons/pulse. To obtain a clear X-ray image in a shorter period of times, we have upgraded the accelerator, which consists of a 3.6 cell photo-cathode rf-gun, a 12 cell standing wave accelerating structure and a 4-mirror planar optical cavity. The expected number of X-ray after upgrade is 1.7x107 photons/pulse with 10% bandwidth. To achieve this target, it is necessary to increase the intensity of an electron beam to 500nC/pulse with 1000 bunches at 30 MeV. We have already started the multi-bunch beam generation and X-ray imaging test after upgrade. The accelerator produces 24 MeV beam with the total charge of 380nC in 300 bunches per pulse now. The aging process is also continued to increase energy and intensity. In this paper, the present status and the results of beam tuning of LUCX accelerator will be reported. (author)

  4. X-Ray microprobe characterization of materials: the case for undulators on advanced storage rings

    International Nuclear Information System (INIS)

    The unique properties of X-rays offer many advantages over electrons and other charged particles for the microcharacterization of materials. X-rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signals to backgrounds than obtained with electrons. Detectable limits for X-rays are a few parts per billion and are 10-3 to 10-5 less than obtained with electrons. Energy deposition in the sample by X-rays is 10-3 to 10-4 less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 6 GeV class with undulators, will be approximately 103 brighter in the X-ray energy range from 5 keV to 35 keV than existing storage rings and provide for X-ray microprobes that are as bright as the most advanced electron probes. Such X-ray microprobes will produce unprecedented low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectoscopies for both chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will be wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine

  5. The U5.0 undulator design for the advanced light source at LBL

    International Nuclear Information System (INIS)

    The U5.0 undulator, currently under design, is the first in a series of insertion devices planned for the Advanced Light Source at LBL. U5.0 parameters include a 5 cm period, 5 m length with a 0.837 T maximum field at a 14 mm gap. A hybrid configuration utilizing Nd-Fe-B permanent magnet material and Vanadium Permendur poles is used for the magnetic structure. Construction is modular with many pole assemblies attached to a pole mount, which in turn is fastened onto one of the backing beams. Vertical field integral correction at the ends is with permanent magnet rotators. The supports structure features a 4-post configuration, a rigid base with 3 kinematic floor supports and 2 rigid 5 m long backing beams that fit within the 2.4 m high accelerator enclosure. The drive system is computer controlled utilizing a stepper motor and shaft encode coupled to a roller-screw/nut and chain drive train. Vacuum chamber design is a rigid configuration with a 10 mm vertical by 218 mm horizontal aperture of 5.5 m length. Chamber fabrication features a two-piece welded chamber of 5083 H321 aluminum. Pumping is with ion and titanium sublimation pumps. 5 figs., 1 tab

  6. Analysis of electro-osmotic flow in a microchannel with undulated surfaces

    CERN Document Server

    Yoshida, Hiroaki; Washizu, Hitoshi

    2016-01-01

    The electro-osmotic flow through a channel between two undulated surfaces induced by an external electric field is investigated. The gap of the channel is very small and comparable to the thickness of the electrical double layers. A lattice Boltzmann simulation is carried out on the model consisting of the Poisson equation for electrical potential, the Nernst--Planck equation for ion concentration, and the Navier--Stokes {\\color{black}equations} for flows of the electrolyte solution. An analytical model that predicts the flow rate is also derived under the assumption that the channel width is very small compared with the characteristic length of the variation along the channel. The analytical results are compared with the numerical results obtained by using the lattice Boltzmann method. In the case of a constant surface charge density along the channel, the variation of the channel width reduces the electro-osmotic flow, and the flow rate is smaller than that of a straight channel. In the case of a surface ch...

  7. Development of Compact Soft X-ray Source Based on Laser Undulator

    CERN Document Server

    Kuroda, Ryunosuke; Minamiguchi, S; Saitô, T; Ueyama, D; Washio, Masakazu

    2004-01-01

    A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on backward Compton scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser and 4 MeV high quality electron beam generated from rf gun system. The range of energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein’s coefficient in this range, a dehydration of the specimens is not necessary. As a preliminary experiment, about 300 eV X-ray generation was carried out. As next step, soft X-ray optics with zone plate was proposed for Soft X-ray microscopy. In this conference, we will report details and results of the experiment.

  8. Hydraulic Transients Caused by Air Expulsion During Rapid Filling of Undulating Pipelines

    Directory of Open Access Journals (Sweden)

    Ciro Apollonio

    2016-01-01

    Full Text Available One of the main issues arising during the rapid filling of a pipeline is the pressure transient which originates after the entrapped air has been expelled at the air release valve. Because of the difference in density between water and air, a pressure transient originates at the impact of the water column. Many authors have analyzed the problem, both from the theoretical and the experimental standpoint. Nevertheless, mainly vertical or horizontal pipelines have been analyzed, whereas in real field applications, the pipe profile is a sequence of ascending and descending pipes, with air release/vacuum valves at high points. To overcome lack of knowledge regarding this latter case, laboratory experiments were carried out to simulate the filling of an undulating pipeline, initially empty at atmospheric pressure. The pipe profile has a high point where an orifice is installed for air venting, so as to simulate the air release valve at intermediate high point of a supply pipeline. In the experiments, the diameter of the orifice and the opening degree of both upstream and downstream valves were varied, in order to analyze their effect on the pressure transient. The experiments were also carried out with a longer descending pipe, in order to assess the effects on the pressure surge of the air volume downstream of the orifice.

  9. Reynolds averaged theory of turbulent shear flows over undulating beds and formation of sand waves.

    Science.gov (United States)

    Bose, Sujit K; Dey, Subhasish

    2009-09-01

    Based on the Reynolds averaged Navier-Stokes (RANS) equations and the time-averaged continuity equation, a theory of turbulent shear flow over an undulating sand bed is developed addressing the instability criterion of plane sand beds in free-surface flows leading to the formation of sand waves. In the analysis, the integration of RANS equations leads to generalized Saint Venant equations, in which the time-averaged streamwise velocity is characterized by a power law obtained from turbulence closure, treating the curvilinear streamlines by the Boussinesq approximation. As a consequence, the modified pressure distribution has a departure from the traditionally linear hydrostatic pressure distribution. The instability analysis of a plane sand bed yields the curves of the Froude number versus nondimensional wave number, determining an instability zone for which at lower Froude numbers (less than 0.8), the plane bed becomes unstable with the formation of dunes; whereas at higher Froude numbers, the plane bed becomes unstable with the formation of standing waves and antidunes. For higher Froude numbers, the experimental data for antidunes lie within the unstable zone; while for lower Froude numbers, the same is found for dunes with some experimental scatter. PMID:19905209

  10. Scapaundulin C, a novel labdane diterpenoid isolated from Chinese liverwort Scapania undulate, inhibits acetylcholinesterase activity.

    Science.gov (United States)

    Kang, Ya-Qi; Zhou, Jin-Chuan; Fan, Pei-Hong; Wang, Shu-Qi; Lou, Hong-Xiang

    2015-12-01

    In the present study, scapaundulin C (1), a new labdane diterpenoid, and four related known compounds scapaundulin A (2), 5α, 8α, 9α-trihydroxy-13E-labden-12-one (3), 5α, 8α-dihydroxy-13E-labden-12-one (4), and (13S)-15-hydroxylabd-8 (17)-en-19-oic acid (5), were isolated from the Chinese liverwort Scapania undulate (L.) Dum., using column chromatography. The structures of these compounds were determined on the basis of 1D- and 2D-NMR analyses. The acetylcholinesterase (AchE) inhibitory activity was evaluated using a bioautographic TLC assay and the cytotoxic activity was evaluated by the MTT method. All the compounds were reported for the first time to exhibit moderate AchE inhibitory activity with minimal inhibitory quantities ranging from 250 to 500 ng. All the compounds were tested for their cytotoxicity against five human tumor cell lines, A549, K562, A2780, Hela, and HT29, and compounds 3 and 4 exhibited moderate inhibitory effects on the growth of A2780 cells. PMID:26721712

  11. Surface undulations of Antarctic ice streams tightly controlled by bedrock topography

    Directory of Open Access Journals (Sweden)

    J. De Rydt

    2012-10-01

    Full Text Available Full Stokes models predict that fast-flowing ice streams transmit information about their bedrock topography most efficiently to the surface for basal undulations with length scales between 1 and 20 times the mean ice thickness. This typical behaviour is independent on the precise values of the flow law and sliding law exponents, and should be universally observable. However, no experimental evidence for this important theoretical prediction has been obtained so far, hence ignoring an important test for the physical validity of current-day ice flow models. In our work we use recently acquired airborne radar data for the Rutford Ice Stream and Evans Ice Stream, and we show that the surface response of fast-flowing ice is highly sensitive to bedrock irregularities with wavelengths of several ice thicknesses. The sensitivity depends on the slip ratio, i.e. the ratio between mean basal sliding velocity and mean deformational velocity. We find that higher values of the slip ratio generally lead to a more efficient transfer, whereas the transfer is significantly dampened for ice that attains most of its surface velocity by creep. Our findings underline the importance of bedrock topography for ice stream dynamics on spatial scales up to 20 times the mean ice thickness. Our results also suggest that local variations in the flow regime and surface topography at this spatial scale cannot be explained by variations in basal slipperiness.

  12. Downsizing of Johansson spectrometer for X-ray fluorescence trace analysis with brilliant undulator source

    CERN Document Server

    Sakurai, K; Inoue, K; Yagi, N

    2001-01-01

    The downsizing of a Johansson-type X-ray fluorescence (XRF) spectrometer has been examined as a way of enhancing detection efficiency with a tolerable loss of energy resolution. A compact spectrometer equipped with a Ge(2 2 0) analyzing crystal with a Rowland radius of 120 mm has been tested with a highly brilliant helical undulator source at BL40XU, SPring-8. The energy resolution obtained for cobalt K alpha sub 1 (6930.32 eV) was 8.8 eV, which is 10-20 times better than that obtained using a Si(Li) detector, and effectively improved the signal-to-background ratio for XRF spectra. The combination of the present spectrometer and a third generation synchrotron source could provide new opportunities for trace analytical applications, which have been difficult so far by conventional synchrotron XRF experiments based on a Si(Li) detector system. The detection limit obtained for solid bulk samples has reached a level of several tens of ppb.

  13. Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H. (Accelerator Systems Division (APS))

    2012-03-27

    The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

  14. Production and properties of two-color radiation generated by using a Free-Electron Laser with two orthogonal undulators

    International Nuclear Information System (INIS)

    We present the analysis of the two-color Self Amplified Spontaneous Emission generated by a Free-Electron Laser amplifier constituted by two orthogonally polarized undulators with different periods and field intensities. Equations deduced in a non-averaged and in an averaged model have been integrated and compared. The two pulses have different frequencies, ruled by proper resonance conditions, and different polarizations, while the total length of the device does not change noticeably with respect to usual single color FELs. The wavelengths of two colors can be changed by choosing different periods, while variation in the magnetic strengths can be used to modify the gain lengths in view of various applications

  15. Construction of a scanning transmission X-ray microscope at the undulator U-41 at BESSY II

    CERN Document Server

    Wiesemann, U; Frueke, R; Guttmann, P; Niemann, B; Rudolph, D; Schmahl, G

    2001-01-01

    A new scanning transmission X-ray microscope for the soft X-ray region is under construction at the BESSY II storage ring. The radiation from the undulator U-41 is monochromatized with a monochromator consisting of a plane mirror and a plane grating with varied line density. For a high resolution image, the zone plate is scanned with a piezoelectric flexure stage. The X-ray flux in the focal spot will be of the order of 10 sup 9 photons/s. The sample is located in air. A pn-CCD detector is used to measure the transmitted intensity.

  16. Hastings Center

    Science.gov (United States)

    ... Public Events October 19, Hastings Center Seminar, Garrison : Human Genetic Engineering: Wh at Can We Do? What Should We ... Public Events October 19, Hastings Center Seminar, Garrison : Human Genetic Engineering: Wh at Can We Do? What Should We ...

  17. ORAL ISSUE OF THE JOURNAL "USPEKHI FIZICHESKIKH NAUK": Ginzburg's invention of undulators and their role in modern synchrotron radiation sources and free electron lasers

    Science.gov (United States)

    Kulipanov, Gennadii N.

    2007-04-01

    Undulators — periodic magnetic structures that were originally introduced by Vitalii Ginzburg in 1947 for electromagnetic radiation generation using relativistic electrons — are among the key elements of modern synchrotron radiation sources and free electron lasers (FELs). In this talk, the history of three generations of storage ring-based synchrotron X-ray sources using wigglers and undulators is briefly traced. Prospects for two types of next-generation space-coherent X-ray sources are discussed, which use long undulators and energy recovery accelerators or, alternatively, employ linear accelerator-based FELs. The recently developed Novosibirsk terahertz FEL facility, currently the world' s most powerful terahertz source, is described. It was the generation of electromagnetic radiation in this range that Ginzburg discussed in his 1947 work.

  18. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, Roman; /SLAC

    2011-09-09

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  19. Excel Center

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Citigroup,one of the World top 500 companies,has now settled in Excel Center,Financial Street. The opening ceremony of Excel Center and the entry ceremony of Citigroup in the center were held on March 31.Government leaders of Xicheng District,the Excel CEO and the heads of Asia-Pacific Region leaders of Citibank all participated in the ceremony.

  20. LCLS X-Ray FEL Output Performance in the Presence of HighlyTime-Dependent Undulator Wakefields

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl L.F.; Emma, Paul; Huang, Heinz-Dieter Nuhn; Stupakov,Gennady; Fawley, William M.; Reiche, Sven

    2005-08-25

    Energy loss due to wakefields within a long undulator, if not compensated by an appropriate tapering of the magnetic field strength, can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive-wall component is the most critical and depends upon the chamber material (e.g., Cu) and its radius. Of recent interest[1] is the so-called ''AC'' component of the resistive-wall wake which can lead to strong variations on very short timescales (e.g., {approx} 20 0fs). To study the expected performance of the LCLS in the presence of these wakefields, we have made an extensive series of start-to-end SASE simulations with tracking codes PARMELA and ELEGANT, and time-dependent FEL simulation codes GENESIS1.3 and GINGER. We discuss the impact of the wakefield losses upon output energy, spectral bandwidth, and temporal envelope of the output FEL pulse, as well as the benefits of a partial compensation of the time-dependent wake losses obtained with a slight z-dependent taper in the undulator field. We compare the taper results to those predicted analytically[2].

  1. LCLS X-Ray FEL Output Performance in the Presence of Highly Time-Dependent Undulator Wakefields

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, W.M.; /LBL, Berkeley; Bane, K.L.F.; Emma, P.; Huang, Z.; Nuhn, H.-D.; Stupakov, G.; /SLAC; Reiche, S.; /UCLA

    2005-09-30

    Energy loss due to wakefields within a long undulator, if not compensated by an appropriate tapering of the magnetic field strength, can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive-wall component is the most critical and depends upon the chamber material (e.g., Cu) and its radius. Of recent interest[1] is the so-called ''AC'' component of the resistive-wall wake which can lead to strong variations on very short timescales (e.g., {approx} 20 fs). To study the expected performance of the LCLS in the presence of these wakefields, we have made an extensive series of start-to-end SASE simulations with tracking codes PARMELA and ELEGANT, and time-dependent FEL simulation codes GENESIS1.3 and GINGER. We discuss the impact of the wakefield losses upon output energy, spectral bandwidth, and temporal envelope of the output FEL pulse, as well as the benefits of a partial compensation of the time-dependent wake losses obtained with a slight z-dependent taper in the undulator field. We compare the taper results to those predicted analytically[2].

  2. Optimization of the LCLS X-Ray FEL Output Performance in the Presence of Strong Undulator Wakefields

    Energy Technology Data Exchange (ETDEWEB)

    Reiche, S.; /UCLA; Bane, K.L.F.; Emma, P.; Huang, Z.; Nuhn, H.D.; Stupakov, G.V.; /SLAC; Fawley, W.M.; /LBL, Berkeley

    2006-03-17

    The Linac Coherent Light Source (LCLS) Free-Electron Laser will operate in the wavelength range of 1.5 to 15 Angstroms. Energy loss due to wakefields within the long undulator can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive component is the most critical and depends upon the chamber material (e.g. Cu) and its radius. To study the expected performance in the presence of these wakefields, we make a series of start-to-end simulations with tracking codes PARMELA and ELEGANT and time-dependent FEL simulation codes Genesis 1.3 and Ginger. We discuss the impact of the wakefield on output energy, spectral bandwidth, and temporal envelope of the output FEL pulse, as well as the benefits of a partial compensation obtained with a slight z dependent taper in the undulator field. We compare these results to those obtained by decreasing the bunch charge or increasing the vacuum chamber radius. We also compare our results to those predicted in concurrent analytical work.

  3. Theoretical computation of the polarization characteristics of an X-ray Free-Electron Laser with planar undulator

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni

    2015-01-01

    We show that radiation pulses from an X-ray Free-Electron Laser (XFEL) with a planar undulator, which are mainly polarized in the horizontal direction, exhibit a suppression of the vertical polarization component of the power at least by a factor $\\lambda_w^2/(4 \\pi L_g)^2$, where $\\lambda_w$ is the length of the undulator period and $L_g$ is the FEL field gain length. We illustrate this fact by examining the XFEL operation under the steady state assumption. In our calculations we considered only resonance terms: in fact, non resonance terms are suppressed by a factor $\\lambda_w^3/(4 \\pi L_g)^3$ and can be neglected. While finding a situation for making quantitative comparison between analytical and experimental results may not be straightforward, the qualitative aspects of the suppression of the vertical polarization rate at XFELs should be easy to observe. We remark that our exact results can potentially be useful to developers of new generation FEL codes for cross-checking their results.

  4. Theoretical computation of the polarization characteristics of an X-ray Free-Electron Laser with planar undulator

    Science.gov (United States)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2015-12-01

    We show that radiation pulses from an X-ray Free-Electron Laser (XFEL) with a planar undulator, which are mainly polarized in the horizontal direction, exhibit a suppression of the vertical polarization component of the power at least by a factor λw2/(4 πLg) 2, where λw is the length of the undulator period and Lg is the FEL field gain length. We illustrate this fact by examining the XFEL operation under the steady state assumption. In our calculations we considered only resonance terms: in fact, non-resonance terms are suppressed by a factor λw3/(4 πLg) 3 and can be neglected. While finding a situation for making quantitative comparison between analytical and experimental results may not be straightforward, the qualitative aspects of the suppression of the vertical polarization rate at XFELs should be easy to observe. We remark that our exact results can potentially be useful to developers of new generation FEL codes for cross-checking their results.

  5. Measurement of X-ray beam emittance using crystal optics at an X-ray undulator beamline

    CERN Document Server

    Kohmura, Y; Awaji, M; Tanaka, T; Hara, T; Goto, S; Ishikawa, T

    2000-01-01

    We present a method of using crystal optics to measure the emittance of the X-ray source. Two perfect crystals set in (++) configuration work as a high-resolution collimator. The phase-space diagram (i.e. beam cross-section and angular distribution) could be determined without any assumptions on the light source. When the measurement is done at short wavelength radiation from undulator, the electron beam emittance is larger than the diffraction limit of the X-rays. Therefore, the electron beam emittance could be estimated. The measurement was done with the hard X-rays of 18.5 and 55 keV from an undulator beamline, BL 47XU, of SPring-8. The horizontal emittance of the X-ray beam was estimated to be about 7.6 nmrad, close to the designed electron beam emittance of the storage ring (7 nmrad). Some portions of the instrumental functions, such as the scattering by filters and windows along the beamline and the slight bent of the crystal planes of the monochromator, could not be precisely evaluated, but an upper li...

  6. Coherent x-rays and vacuum-ultraviolet radiation from storage-ring-based undulators and free electron lasers

    International Nuclear Information System (INIS)

    High-brightness electron storage rings and permanent-magnet technology provide a basis for the development of coherent radiation in the 10- to 1000-A (xuv) spectral range. The most assured route to the production of coherent x-rays and vuv is the simple interaction between properly constrained relativistic electrons and permanent-magnet undulators, a subject that is already well understood and where technology is well advanced. Other techniques are less well developed, but with increasing degrees of technical challenge they will provide additional coherence properties. Transverse optical klystrons (TOKs) provide an opportunity for additional coherence at certain harmonics of longer-wavelength lasers. Free electron lasers (FELs) extend coherence capabilities substantially through two possible routes: one is the development of suitable mirror coatings. Both FEL techniques would provide vuv radiation and soft x rays with extremely narrow spectral content. Research on all of these techniques (undulators, TOKs, and FELs) is possible in a single facility based on a high-brightness electron storage ring, referred to herein as a Coherent xuv Facility (CXF). Individual items from the report were prepared separately for the data base

  7. Plans for production of undulator X-rays on AR and its applications to material and biological sciences

    International Nuclear Information System (INIS)

    This report carries 19 studies. The first two describe 'Hope for Andulator X-Rays' and 'A Plan for Application of AR Synchrotron Radiation Beam'. Three studies on undulator X-rays are presented, which are entitled 'Development of X-Ray Undulator', 'AR-BL-NE Triple Beamline' and 'Fluctuations of Synchrotron Radiation Beam Position and Development of a Beam Position Feedback System for a Beamline of the TRISTAN Accumulation Ring'. Two studies on application to Moessbauer X-rays are contained, which are entitled 'Nuclear Resonant Scattering of Synchrotron Radiation X-Rays' and 'Biological Action of Moessbauer Effect -- Feasibility of Application to Treatment of Cancer'. Two studies on application to research on surface and interface are addressed, which are entitled 'Application to Research on Surface and Interface; Research by Diffraction' and 'How Can Compton Scattering Serve for Study on Surface Layer?'. Five studies on the application to research on submicron crystal structure' are presented, which are entitled Application to Research on Submicron Crystal Structure; Inorganic and Mineral Substances', 'Comments on Application to Research on Submicron Crystal Structure', etc. The report also contains two studies on abnormal scattering and three studies on microbeam X-rays. (N.K.)

  8. Volume-equated high- and low-repetition daily undulating programming strategies produce similar hypertrophy and strength adaptations.

    Science.gov (United States)

    Klemp, Alex; Dolan, Chad; Quiles, Justin M; Blanco, Rocky; Zoeller, Robert F; Graves, B Sue; Zourdos, Michael C

    2016-07-01

    The overarching aim of this study was to compare volume-equated high-repetition daily undulating periodization (DUPHR) versus a low-repetition daily undulating periodization (DUPLR) program for muscle performance. Sixteen college-aged (23 ± 3 years) resistance-trained males were counterbalanced into 2 groups: (i) DUPHR (n = 8), with a weekly training order of 12 repetitions (Day 1), 10 repetitions (Day 2), and 8 repetitions (Day 3); and (ii) DUPLR (n = 8), with a weekly training order of 6 repetitions (Day 1), 4 repetitions (Day 2), and 2 repetitions (Day 3). Both groups trained 3 times/week for 8 weeks on nonconsecutive days, with pre- and post-training testing during weeks 1 and 8. Participants performed only squat and bench press exercises each session. Changes in one-repetition maximum (1RM) strength, muscle thickness (MT), and muscular endurance (ME) were assessed. Both groups significantly increased 1RM strength for both squat and bench press (p 0.05). Similarly, both groups experienced significant increases in chest, lateral quadriceps distal, and anterior quadriceps MT (p 0.05). ME did not significantly change in the squat or bench press for either group (p > 0.05); however, for squat ME, a moderate effect size was observed for DUPHR (0.57) versus a trivial effect size for DUPLR (0.17). Our findings suggest that in previously trained males, training volume is a significant contributor to strength and hypertrophy adaptations, which occur independently of specific repetition ranges. PMID:27218448

  9. Nd2Fe14B and Pr2Fe14B magnets characterisation and modelling for cryogenic permanent magnet undulator applications

    International Nuclear Information System (INIS)

    Cryogenic permanent magnet undulators take benefit from improved magnetic properties of RE2Fe14B (Rare Earth based magnets) at cryogenic temperatures for achieving short period high magnetic field. In particular, using Praseodymium instead of Neodymium generally employed for insertion devices avoids limitation due to Spin Reorientation Transition phenomenon. Magnetic properties of magnet samples (Nd2Fe14B and Pr2Fe14B) versus temperature have been investigated and applied to a 20 mm period Nd2Fe14B (BH50) and to a 18 mm period Pr2Fe14B (CR53) systems. Four period undulators have been built, characterised and compared to the models.

  10. Job center

    Science.gov (United States)

    To better meet the needs of AGU members, a program has been started to increase the effectiveness of the Job Center activity at the Spring and Fall Meetings. As a result, participation in the Job Center at the 1988 AGU Spring Meeting in Baltimore increased substantially compared to previous Spring Meetings. The number of employers, applicants, and interviews scheduled more than doubled compared to the 1987 Spring Job Center.In order to make the meeting Job Centers even better, a survey is being conducted of employers and applicants who participated in the 1988 Spring Job Center. Evaluation of this survey will be useful in continuing increased participation in and the effectiveness of the Job Center at the 1988 Fall Meeting. Past participants and those interested in the future of the Job Center are encouraged to forward comments and suggestions to AGU, Member Programs Division, 2000 Florida Ave., N.W., Washington, DC 20009.

  11. On simulating lipid bilayers with an applied surface tension: periodic boundary conditions and undulations.

    Science.gov (United States)

    Feller, S E; Pastor, R W

    1996-01-01

    As sketched in Fig. 1, a current molecular dynamics computer simulation of a lipid bilayer fails to capture significant features of the macroscopic system, including long wavelength undulations. Such fluctuations are intrinsically connected to the value of the macroscopic (or thermodynamic) surface tension (cf. Eqs. 1 and 9; for a related treatment, see Brochard et al., 1975, 1976). Consequently, the surface tension that might be evaluated in an MD simulation should not be expected to equal the surface tension obtained from macroscopic measurements. Put another way, the largest of the three simulations presented here contained over 16,000 atoms and required substantial computer time to complete, but modeled a system of only 36 lipids per side. From this perspective it is not surprising that the system is not at the thermodynamic limit. An important practical consequence of this effect is that simulations with fluctuating area should be carried out with a nonzero applied surface tension (gamma 0 of Fig. 2) even when the macroscopic tension is zero, or close to zero. Computer simulations at fixed surface area, which can explicitly determine pressure anisotropy at the molecular level, should ultimately lend insight into the value of gamma 0, including its dependence on lipid composition and other membrane components. As we have noted and will describe further in separate publications (Feller et al., 1996; Feller et al., manuscript in preparation), surface tensions obtained from simulations can be distorted by inadequate initial conditions and convergence, and are sensitive to potential energy functions, force truncation methods, and system size; it is not difficult, in fact, to tune terms in the potential energy function so as to yield surface tensions close to zero. This is why parameters should be tested extensively on simpler systems, for example, monolayers. The estimates of gamma 0 that we have presented here should be regarded as qualitative, and primarily

  12. On simulating lipid bilayers with an applied surface tension: periodic boundary conditions and undulations.

    Science.gov (United States)

    Feller, S E; Pastor, R W

    1996-09-01

    As sketched in Fig. 1, a current molecular dynamics computer simulation of a lipid bilayer fails to capture significant features of the macroscopic system, including long wavelength undulations. Such fluctuations are intrinsically connected to the value of the macroscopic (or thermodynamic) surface tension (cf. Eqs. 1 and 9; for a related treatment, see Brochard et al., 1975, 1976). Consequently, the surface tension that might be evaluated in an MD simulation should not be expected to equal the surface tension obtained from macroscopic measurements. Put another way, the largest of the three simulations presented here contained over 16,000 atoms and required substantial computer time to complete, but modeled a system of only 36 lipids per side. From this perspective it is not surprising that the system is not at the thermodynamic limit. An important practical consequence of this effect is that simulations with fluctuating area should be carried out with a nonzero applied surface tension (gamma 0 of Fig. 2) even when the macroscopic tension is zero, or close to zero. Computer simulations at fixed surface area, which can explicitly determine pressure anisotropy at the molecular level, should ultimately lend insight into the value of gamma 0, including its dependence on lipid composition and other membrane components. As we have noted and will describe further in separate publications (Feller et al., 1996; Feller et al., manuscript in preparation), surface tensions obtained from simulations can be distorted by inadequate initial conditions and convergence, and are sensitive to potential energy functions, force truncation methods, and system size; it is not difficult, in fact, to tune terms in the potential energy function so as to yield surface tensions close to zero. This is why parameters should be tested extensively on simpler systems, for example, monolayers. The estimates of gamma 0 that we have presented here should be regarded as qualitative, and primarily

  13. Functional Centering

    CERN Document Server

    Hahn, M

    1996-01-01

    Based on empirical evidence from a free word order language (German) we propose a fundamental revision of the principles guiding the ordering of discourse entities in the forward-looking centers within the centering model. We claim that grammatical role criteria should be replaced by indicators of the functional information structure of the utterances, i.e., the distinction between context-bound and unbound discourse elements. This claim is backed up by an empirical evaluation of functional centering.

  14. Nonlinear undulator tapering in conventional SASE regime at baseline electron beam parameters as a way to optimize the radiation characteristics of the European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni; Zagorodnov, Igor [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany)

    2013-09-15

    We demonstrate that the output radiation characteristics of the European XFEL sources at nominal operation point can be easily made significantly better than what is currently reported in the TDRs of scientific instruments and X-ray optics. In fact, the output SASE characteristics of the baseline European XFEL have been previously optimized assuming uniform undulators at a nominal operating point of 5 kA peak current, without considering the potential of undulator tapering in the SASE regime. In order to illustrate this point, we analyze the case of an electron bunch with nominal parameters. Based on start-to-end simulations, we demonstrate that nonlinear undulator tapering allows one to achieve up to a tenfold increase in peak power and photon spectral density in the conventional SASE regime, without modification to the baseline design. The FEL code Genesis has been extensively used for these studies. In order to increase our confidence in simulation results, we cross-checked outcomes by reproducing simulations in the deep nonlinear SASE regime with tapered undulator using the code ALICE.

  15. Distribution center

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Distribution center is a logistics link fulfill physical distribution as its main functionGenerally speaking, it's a large and hiahly automated center destined to receive goods from various plants and suppliers,take orders,fill them efficiently,and deliver goods to customers as quickly as possible.

  16. Plasma density undulations correlated with thermospheric neutral mass density in the daytime low-latitude to midlatitude topside ionosphere

    Science.gov (United States)

    Park, Jaeheung; Lühr, Hermann; Nishioka, Michi; Kwak, Young-Sil

    2015-08-01

    Plasma density undulations in the dayside low-latitude/midlatitude ionospheric F region were often attributed to thermospheric gravity waves (TGWs). However, the relationship between the former and the latter has been at best indirectly evidenced. In this study we investigate daytime fluctuations in neutral mass density (ρ) and plasma density (ne) measured onboard CHAMP from 2001 to 2010. A significant amount of daytime fluctuations in ne is strongly correlated with in situ fluctuations of ρ, which we term "TGW-related ne fluctuations." The TGW-related ne fluctuations are (1) stronger in the winter hemisphere than in the summer hemisphere and (2) strongest in the South American sector during June solstice months. These climatological features are in general agreement with those of TGWs reported previously, especially at midlatitudes. On the other hand, the relative amplitude of TGW-related ne fluctuations does not depend strongly on solar activity.

  17. High-Brightness Beams from a Light Source Injector The Advanced Photon Source Low-Energy Undulator Test Line Linac

    CERN Document Server

    Travish, G; Borland, M; Hahne, M; Harkay, K C; Lewellen, J W; Lumpkin, Alex H; Milton, S V; Sereno, N S

    2000-01-01

    The use of existing linacs, and in particular light source injectors, for free-electron laser (FEL) experiments is becoming more common due to the desire to test FELs at ever shorter wavelengths. The high-brightness, high-current beams required by high-gain FELs impose technical specifications that most existing linacs were not designed to meet. Moreover, the need for specialized diagnostics, especially shot-to-shot data acquisition, demands substantial modification and upgrade of conventional linacs. Improvements have been made to the Advanced Photon Source (APS) injector linac in order to produce and characterize high-brightness beams. Specifically, effort has been directed at generating beams suitable for use in the low-energy undulator test line (LEUTL) FEL in support of fourth-generation light source research. The enhancements to the linac technical and diagnostic capabilities that allowed for self-amplified spontaneous emission (SASE) operation of the FEL at 530 nm are described. Recent results, includi...

  18. Precision white-beam slit design for high power density x-ray undulator beamlines at the Advanced Photon Source

    International Nuclear Information System (INIS)

    A set of precision horizontal and vertical white-beam slits has been designed for the Advanced Photon Source (APS) X-ray undulator beamlines at Argonne National Laboratory. There are several new design concepts applied in this slit set, including: grazing-incidence knife-edge configuration to minimize the scattering of X-rays downstream, enhanced heat transfer tubing to provide water cooling, and a second slit to eliminate the thermal distortion on the slit knife edge. The novel aspect of this design is the use of two L-shaped knife-edge assemblies, which are manipulated by two precision X-Z stepping linear actuators. The principal and structural details of the design for this slit set are presented in this paper

  19. The E166 experiment: Development of an undulator-based polarized positron source for the international linear collider

    Indian Academy of Sciences (India)

    J Kovermann; A Stahl; A A Mikhailichenko; D Scott; G A Moortgat-Pick; V Gharibyan; P Pahl; R Pöschl; K P Schüler; K Laihem; S Riemann; A Schälicke; R Dollan; H Kolanoski; T Lohse; T Schweizer; K T McDonald; Y Batygin; V Bharadwaj; G Bower; F-J Decker; C Hast; R Iverson; J C Sheppard; Z Szalata; D Walz; A Weidemann; G Alexander; E Reinherz-Aronis; S Berridge; W Bugg; Y Efrimenko

    2007-12-01

    A longitudinal polarized positron beam is foreseen for the international linear collider (ILC). A proof-of-principle experiment has been performed in the final focus test beam at SLAC to demonstrate the production of polarized positrons for implementation at the ILC. The E166 experiment uses a 1 m long helical undulator in a 46.6 GeV electron beam to produce a few MeV photons with a high degree of circular polarization. These photons are then converted in a thin target to generate longitudinally polarized + and -. The positron polarization is measured using a Compton transmission polarimeter. The data analysis has shown asymmetries in the expected vicinity of 3.4% and ∼ 1% for photons and positrons respectively and the expected positron longitudinal polarization is covering a range from 50% to 90%.

  20. Experimental research on the residual magnetization of a rare-earth permanent magnet for a cryogenic undulator

    Institute of Scientific and Technical Information of China (English)

    He Yong-Zhou

    2013-01-01

    The magnetic properties of commercial polycrystalline Nd2Fe14B (N50M,N45H,N40SH,N35EH) and Sm2Co17 (XG30/20,XG26/25,XG22/20) magnets at cryogenic temperatures were tested by using a comprehensive physical properties measurement system (PPMS).The results show that the spin tilt temperature Tst of Nd2Fe14B magnets is closely related to intrinsic coercivity Hci,N50M and N45H with smaller Hci show a residual magnetization jump at 235 K and 225 K,respectively.For Sm2Co17 magnets,in 50-300 K,with temperature decreasing,residual magnetization Mrc shows a nearly linear increase,while in 10-50 K,Mrc has little change.The research results provide a reference for cryogenic undulators and other high-precision cryogenic devices.

  1. Senior Centers

    Medline Plus

    Full Text Available ... Karen Albers] We provide a wide variety of activities -- physical, health, mental health programs with Senior Plus, cognitive ... of games. [Narrator] Many senior centers also offer exercise programs. [Karen Albers] We offer aerobics, tai chi, ...

  2. Senior Centers

    Medline Plus

    Full Text Available ... Living independently at home is something many older adults would like to do as long as they can. Senior centers, adult day care, transportation, and meals programs are long- ...

  3. Senior Centers

    Medline Plus

    Full Text Available ... variety of social and recreational activities. [Karen Albers] We provide a wide variety of activities -- physical, health, ... senior centers also offer exercise programs. [Karen Albers] We offer aerobics, tai chi, tap dancing, ballroom dancing, ...

  4. Senior Centers

    Medline Plus

    Full Text Available ... transportation, and meals programs are long-term care services available in the community which make it easier ... about senior centers and other long-term care services available in your community, contact the Eldercare Locator ...

  5. Senior Centers

    Medline Plus

    Full Text Available ... of games. [Narrator] Many senior centers also offer exercise programs. [Karen Albers] We offer aerobics, tai chi, ... chi, tap dancing, ballroom dancing, square dancing, chair exercise, arthritis classes, yoga, and lots of dancing. [Narrator] ...

  6. Neuromuscular Responses to Short-Term Resistance Training With Traditional and Daily Undulating Periodization in Adolescent Elite Judoka.

    Science.gov (United States)

    Ullrich, Boris; Pelzer, Thiemo; Oliveira, Sergio; Pfeiffer, Mark

    2016-08-01

    Ullrich, B, Pelzer, T, Oliveira, S, and Pfeiffer, M. Neuromuscular responses to short-term resistance training with traditional and daily undulating periodization in adolescent elite judoka. J Strength Cond Res 30(8): 2083-2099, 2016-The influence of different periodization models on neuromuscular outcomes after short-term strength training periods has not been examined in adolescent athletes. Eleven elite judoka (age: 14.8 ± 0.6 years, height: 163.2 ± 7.5 cm, body mass: 57.3 ± 11.1 kg, 5 boys/6 girls, and strength training experience: 2.7 ± 1.1 years) performed two 4-week strength training mesocycles (each with 12 sessions) with either traditional (TP) or daily undulating (DUP) periodization. Both mesocycles were separated by a 7-week washout period and added to the regular judo training. Strength training was performed as lifting and lowering of weights using squats, knee flexion curl, clean & jerk, snatch, bench press, barbell bench pull, and lat pull-down. The mesocycles were equated for the number of repetitions and different intensity zones (50-90% of 1 repetition maximum [1RM]), addressing the optimization of strength, power, or velocity. Laboratory and 1RM testing was carried out 2 times during the baseline (T1 and T2), after the TP mesocycle (T3), after the washout period (T4), and after the DUP mesocycle (T5). Isometric knee extensor and knee flexor maximum voluntary contractive capacity (MVC), electromyographic-estimated neural drive of the quadriceps femoris, vastus lateralis (VL) muscle architecture, and 1RMs of all training exercises were measured. ANOVA revealed moderate (5.5-13.5%) but significant (p ≤ 0.05) temporal gains in knee extensor MVC, 1RMs, and VL architecture during both the mesocycles. Wilcoxon tests detected no significant differences for the percentage changes of any outcome between the mesocycles. For adolescent judoka, TP and DUP were equally adept in improving neuromuscular outcomes during short-term training periods. PMID

  7. Senior Centers

    Medline Plus

    Full Text Available ... dancing. [Narrator] These centers can provide entree to new activities and expand a person’s social contacts. [Karen ... meeting all their interests and introducing them to new things; whether it’s an arts and crafts project, ...

  8. Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II

    Energy Technology Data Exchange (ETDEWEB)

    Park, So Yeong; Hong, Chung Ki [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Lim, Jun, E-mail: limjun@postech.ac.kr [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)

    2014-04-15

    We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 μm (horizontal) × 50 μm (vertical)

  9. Compensating the Electron Beam Energy Spread by the Natural Transverse Gradient of Laser Undulator in All-Optical X-ray Sources

    CERN Document Server

    Zhang, Tong; Deng, Haixiao; Wang, Dong; Dai, Zhimin; Zhao, Zhentang

    2013-01-01

    All-optical schemes provide a potential to dramatically cut off the size and cost of x-ray light sources to the university-laboratory scale, with the combination of the laser-plasma accelerator and the laser undulator. However, the large longitudinal energy spread of the electron beam from laser-plasma accelerator may hinder the way to high brightness of these all-optical light sources. In this letter, the beam energy spread effect is proposed to be significantly compensated by the natural transverse gradient of a laser undulator when properly dispersing the electron beam transversely. Theoretical analysis and numerical simulations on conventional laser-Compton scattering sources and high-gain all-optical x-ray free-electron lasers with the electron beams from laser-plasma accelerators are presented.

  10. Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY

    International Nuclear Information System (INIS)

    Three vacuum chambers for the VUV SASE FEL undulator sections at the TESLA Test Facility (TTF) were designed, built, tested and installed. Each chamber is 4.5 m long and of 11.5 mm thick. The inner diameter of the beam pipe is 9.5 mm. The rectangular chamber profile with a width of 128 mm is used to integrate beam position monitors and steerers. This is needed to provide a good overlap between the electron and the photon beam over the entire undulator length. The chambers are built in an aluminum extrusion technology developed for the insertion device vacuum chambers of the Advanced Photon Source. After manufacturing, special processing was performed to reach low outgassing rates (-11mbar·l/s·cm2) and particle-free chambers. Mounting of the chambers at TTF were performed under clean room conditions better class 100

  11. Design and Performance of Undulator Beamline (BL7U) for in-situ Observation of Synchrotron Radiation Stimulated Etching by STM

    International Nuclear Information System (INIS)

    An undulator beamline (BL7U) equipped with an ultra-high vacuum STM system is constructed at the UVSOR facility to investigate excitation energy dependence in synchrotron radiation (SR) stimulated etching. The SR beam is focused using two cylindrical mirrors on the sample surface just under the STM tip. The sample is cleaned by direct current heating and transferred to the sample holder for the STM measurements. The photon flux density is calculated to be 1019 photons (cm2 sec 100mA)-1 within the spot of 0.67 mm (H) x 0.17 mm (V) on the sample surface at the first harmonic tuned to 100 eV. The hydrogen adsorbed Si (111) surfaces were investigated using the STM apparatus before the undulator irradiation experiments were performed

  12. Improving the energy-extraction efficiency of laser-plasma accelerator driven free-electron laser using transverse-gradient undulator with focusing optics and longitudinal tapering

    CERN Document Server

    Zhou, G; Wu, J; Zhang, T

    2016-01-01

    It is reported that [Z. Huang et al., Phys. Rev. Lett. 109, 204801 (2012)], high-gain free-electron laser (FEL) can be generated by transverse-dispersed electron beams from laser-plasma accelerators (LPAs) using transverse-gradient undulator (TGU) assuming an ideal constant dispersion function without focusing optics. The constant dispersion function keeps electrons beyond the resonant energy bandwidth still being on resonant with the FEL radiation. Instead, in this paper, the case with focusing optics in an LPA-driven FEL using TGU is numerically studied, in which the dispersion function should be monotonously decreasing along the undulator. Even though the FEL resonance is not always satisfied for off-energy electrons in this case, through subtly optimizing the initial dispersion and focusing parameters, it is feasible to achieve a similar radiation power to the case assuming an ideal constant dispersion function without focusing optics, and meanwhile, to attain a good transverse coherence. Moreover, higher...

  13. Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY

    CERN Document Server

    Hahn, U; Pflüger, J; Rüter, M; Schmidt, G; Trakhtenberg, E

    2000-01-01

    Three vacuum chambers for the VUV SASE FEL undulator sections at the TESLA Test Facility (TTF) were designed, built, tested and installed. Each chamber is 4.5 m long and of 11.5 mm thick. The inner diameter of the beam pipe is 9.5 mm. The rectangular chamber profile with a width of 128 mm is used to integrate beam position monitors and steerers. This is needed to provide a good overlap between the electron and the photon beam over the entire undulator length. The chambers are built in an aluminum extrusion technology developed for the insertion device vacuum chambers of the Advanced Photon Source. After manufacturing, special processing was performed to reach low outgassing rates (<1x10 sup - sup 1 sup 1 mbar centre dot l/s centre dot cm sup 2) and particle-free chambers. Mounting of the chambers at TTF were performed under clean room conditions better class 100.

  14. Measurement of the positron polarization at an helical undulator based positron source for the international linear collider ILC. The E-166 experiment at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Laihem

    2008-06-05

    A helical undulator based polarized positron source is forseen at a future International Linear Collider (ILC). The E-166 experiment has tested this scheme using a one meter long, short-period, pulsed helical undulator installed in the Final Focus Test Beam (FFTB) at SLAC. A low-emittance 46.6 GeV electron beam passing through this undulator generated circularly polarized photons with energies up to about 8 MeV. The generated photons of several MeV with circular polarization are then converted in a relatively thin target to generate longitudinally polarized positrons. Measurements of the positron polarization have been performed at 5 different energies of the positrons. In addition electron polarization has been determined for one energy point. For a comparison of the measured asymmetries with the expectations detailed simulations were necessary. This required upgrading GEANT4 to include the dominant polarization dependent interactions of electrons, positrons and photons in matter. The measured polarization of the positrons agrees with the expectations and is for the energy point with the highest polarization at 6MeV about 80%. (orig.)

  15. The formation mechanism and impact of streamwise vortices on NACA 0021 airfoil's performance with undulating leading edge modification

    Science.gov (United States)

    Rostamzadeh, N.; Hansen, K. L.; Kelso, R. M.; Dally, B. B.

    2014-10-01

    Wings with tubercles have been shown to display advantageous loading behavior at high attack angles compared to their unmodified counterparts. In an earlier study by the authors, it was shown that an undulating leading-edge configuration, including but not limited to a tubercled model, induces a cyclic variation in circulation along the span that gives rise to the formation of counter-rotating streamwise vortices. While the aerodynamic benefits of full-span tubercled wings have been associated with the presence of such vortices, their formation mechanism and influence on wing performance are still in question. In the present work, experimental and numerical tests were conducted to further investigate the effect of tubercles on the flow structure over full-span modified wings based on the NACA 0021 profile, in the transitional flow regime. It is found that a skew-induced mechanism accounts for the formation of streamwise vortices whose development is accompanied by flow separation in delta-shaped regions near the trailing edge. The presence of vortices is detrimental to the performance of full-span wings pre-stall, however renders benefits post-stall as demonstrated by wind tunnel pressure measurement tests. Finally, primary and secondary vortices are identified post-stall that produce an enhanced momentum transfer effect that reduces flow separation, thus increasing the generated amount of lift.

  16. Planar undulator motion excited by a fixed traveling wave: Quasiperiodic Averaging, normal forms and the FEL Pendulum

    CERN Document Server

    Ellison, James A; Vogt, Mathias; Gooden, Matthew

    2013-01-01

    We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray Free Electron Laser (FEL) regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wavelength of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so-called ponderomotive phase. As the wavelength varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) normal form approximations. For a special initial condition and on resonance, the NtoR normal form reduces to the well-known FEL pendulum system. We then state and prove NR and Nt...

  17. IRASM Center

    International Nuclear Information System (INIS)

    IRASM is a national center for radiation processing developed around an industrial Co60 gamma irradiator. Being a department in an R and D national institute, IRASM Center is dealing with radiation treatment, pre/post microbiological control, validation of irradiation sterilization, detection of irradiated foodstuffs. Training is available for operators of new irradiation facilities focused on radiation technologies, dosimetry, sterilization, food treatment, conservation by irradiation of cultural heritage, quality assurance. Expertise on proper choosing the plastics for packaging versus dose is offered to the potential clients. IRASM Center is also involved in interdisciplinary applied research like chitosan treatment, sterile male technique or implementation of irradiation step in production of pharmaceuticals. All important activities: irradiation treatment, dosimetry, microbiology, detection of irradiated food, radioprotection, nuclear safety, physical protection. are performed in accordance with the proper standards in the frame of a certified quality management system. In this way Co60 industrial sources, a byproduct of certain nuclear power plants like Candu type, appear to be the key of a large technical and R and D domain. (authors)

  18. Longitudinal and seasonal variations in the occurrence of sunrise undulation at the dip equator: A study using Trivandrum and Jicamarca Digital Ionosonde and Jicamarca Incoherent Scatter radar measurements

    Science.gov (United States)

    Ambili, K. M.; St-Maurice, Jean-Pierre; Choudhary, Raj Kumar

    At night, the absence of photo ionization in combination with sustained downward plasma motion means that the F region can be severely depleted at the magnetic equator at the end of the night. As a result, there can be, at sunrise, a sudden upward jump in altitude of the F region peak which is then followed by a quick descent in association with the downward motion of the photo ionization production peak. This constitutes what has been described as the equatorial sunrise undulation. Its anecdotal existence has been reported over Jicamarca (120 S, 76.90 W, 1.70 S dip-latitude) while it has been seen repeatedly over Trivandrum (8.470 N, 76.920 E, 0.170 S dip latitude), India, particularly during equinox conditions. Seasonal variations in the occurrence of sunrise undulation in the F-region peak height (hmF2) at two longitudinally separated geomagnetic equatorial stations, namely Jicamarca and Trivandrum are being presented. Measurements from Digital ionosondes, located at these two stations, have been used in this study. A fast descends in hmF2 after the local F region sunrise was quite visible at both the stations. The frequency of occurrence of sunrise undulation at Trivandrum, however, was high compared to the same at Jicamarca. There were noticeable differences in the seasonal occurrence of sunrise undulation at the two places. While it was observed throughout the year at Trivandrum, there was a distinct seasonal preference of occurrence at Jicamarca, at least in the year 2010, a low solar active period. Its frequency of occurrence at Jicamarca was high during winter (June) solstice, low during equinox (March) and had almost negligible occurrence during summer solstice (December). We show that (1) plasma density during sunrise at Jicamarca on average was twice as much as at Trivandrum, and (2) average height of hmF2 during night at Jicamarca was higher (~100km ) during equinox and solstice months compared to the same at Trivandrum. Our results suggest that the

  19. Sub-Picosecond Tunable Hard X-Ray Undulator Source for Laser/X-Ray Pump-Probe Experiments

    Science.gov (United States)

    Ingold, G.; Beaud, P.; Johnson, S.; Streun, A.; Schmidt, T.; Abela, R.; Al-Adwan, A.; Abramsohn, D.; Böge, M.; Grolimund, D.; Keller, A.; Krasniqi, F.; Rivkin, L.; Rohrer, M.; Schilcher, T.; Schmidt, T.; Schlott, V.; Schulz, L.; van der Veen, F.; Zimoch, D.

    2007-01-01

    The FEMTO source under construction at the μXAS beamline is designed to enable tunable time-resolved laser/x-ray absorption and diffraction experiments in photochemistry and condensed matter with ps- and sub-ps resolution. The design takes advantage of (1) the highly stable operation of the SLS storage ring, (2) the reliable high harmonic operation of small gap, short period undulators to generate hard x-rays with energy 3-18 keV at 2.4 GeV beam energy, and (3) the progress in high power, high repetition rate fs solid-state laser technology to employ laser/e-beam `slicing' to reach a time resolution of ultimately 100 fs. The source will profit from the inherently synchronized pump (laser I: 100 fs, 2 mJ, 1 kHz) and probe (sliced X-rays, laser II: 50 fs, 5 mJ, 1 kHz) pulses, and from the excellent stability of the SLS storage ring which is operated in top-up mode and controlled by a fast orbit feedback (FOFB). Coherent radiation emitted at THz frequencies by the sliced 100 fs electron bunches will be monitored as on-line cross-correlation signal to keep the laser-electron beam interaction at optimum. The source is designed to provide at 8 keV (100 fs) a monochromized flux of 104 ph/s/0.01% bw (Si crystal monochromator) and 106 ph/s/1.5% bw (multilayer monochromator) at the sample. It is operated in parasitic mode using a hybrid bunch filling pattern. Because of the low intensity measurements are carried out repetitively over many shots using refreshing samples and gated detectors. `Diffraction gating' experiments will be used to characterize the sub-ps X-ray pulses.

  20. Research Development and Analysis of Biomimetic Robot Fish Propelled by Undulating Fins%波动鳍仿生机器鱼研究进展与分析

    Institute of Scientific and Technical Information of China (English)

    徐飞然; 王光明; 谭晓朋

    2015-01-01

    One of the most popular propulsion motion of MPF fishes is propelled by undulating fins, which made the ifsh have the characteristic of high efifciency, high stabilit y and strong maneuverability. In recent years, because of the strong efforts to develop marine resources and the urgent need to improve military equipment, the bio-mimetic robot ifsh have got more and more attractions. In the ifrst, making a brief instruction and classiifcation to the ifsh which propelled by undulating ifns, then summarize the bio-mimetic undulating robot ifsh in the two respects of propulsive mechanism study and bio-mimetic ifsh robots development, at last make some discuss and analysis to the key technologies.%依靠鳍的波动实现推进的中央鳍/对鳍(Median and/or Paired Fin,MPF)模式鱼类在运动过程中身体可以不发生变形而获得推力,具有高效率,高稳定性和强机动的游动特点,对水下推进器的研发具有极大的参考价值,近年来在加强海洋资源开发力度和加快军事装备革新步伐的号召下,波动鳍仿生机器鱼受到越来越多科研人员的关注。首先对波动鳍游动鱼类进行简要介绍和分类,从机理研究和仿鱼样机两个方面对其进行综述,然后对相关的关键技术进行了分析和讨论。

  1. Compensating the electron beam energy spread by the natural transverse gradient of laser undulator in all-optical x-ray light sources

    OpenAIRE

    ZHANG, Tong; Feng, Chao; Deng, Haixiao; Wang, Dong; Dai, Zhimin; Zhao, Zhentang

    2013-01-01

    All-optical ideas provide a potential to dramatically cut off the size and cost of x-ray light sources to the university-laboratory scale, with the combination of the laser-plasma accelerator and the laser undulator. However, the large longitudinal energy spread of the electron beam from laser-plasma accelerator may hinder the way to high brightness of these all-optical light sources. In this paper, the beam energy spread effect is proposed to be significantly compensated by the natural trans...

  2. Planar undulator motion excited by a fixed traveling wave. Quasiperiodic averaging normal forms and the FEL pendulum

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, James A.; Heinemann, Klaus [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mathematics and Statistics; Vogt, Mathias [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Gooden, Matthew [North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics

    2013-03-15

    We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray FEL regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wave length {lambda} of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so- called ponderomotive phase. As {lambda} varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) MoA normal form approximations. The NtoR normal forms contain a parameter which measures the distance from a resonance. For a special initial condition, for the planar motion and on resonance, the NtoR normal form reduces to the well known FEL pendulum system. We then state and prove NR and NtoR first-order averaging theorems which give explicit error bounds for the normal form approximations. We prove the theorems in great detail, giving the interested reader a tutorial on mathematically rigorous perturbation theory in a context where the proofs are easily understood. The proofs are novel in that they do not use a near identity transformation and they use a system of differential inequalities. The NR case is an example of quasiperiodic averaging where the small divisor problem enters in the simplest possible way. To our knowledge the planar prob- lem has not been analyzed with the generality we aspire to here nor has the standard FEL pendulum system been derived with associated error bounds as we do here. We briefly discuss the low gain theory in light of our NtoR normal form. Our mathematical treatment of the noncollective FEL beam dynamics problem in

  3. Wave optical description of the Traveling-Wave Thomson-Scattering optical undulator field and its application to the TWTS-FEL

    International Nuclear Information System (INIS)

    We show that X-ray optical free-electron lasers (OFELs) can be realized using Traveling-Wave Thomson-Scattering (TWTS). In TWTS pulse front tilted laser pulses are scattered off relativistic electron bunches in a side-scattering geometry. The pulse-front tilt guarantees overlap between laser and electrons over distances in the meter range while both are traveling in different directions. An interaction distance of 90 cm is obtained in a setup were 590 MeV electrons scatter off a petawatt class laser incident under an angle of 4.5°. The amplification of the 1.5 Å radiation saturates at the end of the interaction. In order to account for spatial and temporal dispersion introduced with the pulse front tilt, we develop an exact three-dimensional analytical description of TWTS pulses that can be used in three-dimensional simulations of the radiation amplification process. The wave-optical formulation of the TWTS pulse includes dispersion to all orders and provides a general description of laser pulses diffracted at VLS gratings. - Highlights: • Optical FELs can be realized with Traveling-Wave Thomson-Scattering (TWTS). • Pulse front tilted high-power lasers provide for optical undulators. • All dispersion effects can be controlled, resulting in long undulator lengths. • A fully analytical 3D, wave-optical description of TWTS is presented

  4. Proposal to generate 10 TW level femtosecond X-ray pulses from a baseline undulator in conventional SASE regime at the European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni; Zagorodnov, Igor [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany)

    2013-08-15

    Output characteristics of the European XFEL have been previously studied assuming an operation point at 5 kA peak current. In this paper we explore the possibility to go well beyond such nominal peak current level. In order to illustrate the potential of the European XFEL accelerator complex we consider a bunch with 0.25 nC charge, compressed up to a peak current of 45 kA. An advantage of operating at such high peak current is the increase of the X-ray output peak power without any modification to the baseline design. Based on start-to-end simulations, we demonstrate that such high peak current, combined with undulator tapering, allows one to achieve up to a 100-fold increase in a peak power in the conventional SASE regime, compared to the nominal mode of operation. In particular, we find that 10 TW-power level, femtosecond x-ray pulses can be generated in the photon energy range between 3 keV and 5 keV, which is optimal for single biomolecule imaging. Our simulations are based on the exploitation of all the 21 cells foreseen for the SASE3 undulator beamline, and indicate that one can achieve diffraction to the desired resolution with 15 mJ (corresponding to about 3.10{sup 13} photons) in pulses of about 3 fs, in the case of a 100 nm focus at the photon energy of 3.5 keV.

  5. Geoid undulations and gravity anomalies over the Aral Sea, the Black Sea and the Caspian Sea from a combined GEOS-3/SEASAT/GEOSAT altimeter data set

    Science.gov (United States)

    Au, Andrew Y.; Brown, Richard D.; Welker, Jean E.

    1991-01-01

    Satellite-based altimetric data taken by GOES-3, SEASAT, and GEOSAT over the Aral Sea, the Black Sea, and the Caspian Sea are analyzed and a least squares collocation technique is used to predict the geoid undulations on a 0.25x0.25 deg. grid and to transform these geoid undulations to free air gravity anomalies. Rapp's 180x180 geopotential model is used as the reference surface for the collocation procedure. The result of geoid to gravity transformation is, however, sensitive to the information content of the reference geopotential model used. For example, considerable detailed surface gravity data were incorporated into the reference model over the Black Sea, resulting in a reference model with significant information content at short wavelengths. Thus, estimation of short wavelength gravity anomalies from gridded geoid heights is generally reliable over regions such as the Black Sea, using the conventional collocation technique with local empirical covariance functions. Over regions such as the Caspian Sea, where detailed surface data are generally not incorporated into the reference model, unconventional techniques are needed to obtain reliable gravity anomalies. Based on the predicted gravity anomalies over these inland seas, speculative tectonic structures are identified and geophysical processes are inferred.

  6. Effects of Pre - Season Short - Term Daily Undulating Periodized Training on Muscle Strength and Sprint Performance of Under - 20 Soccer Players

    Directory of Open Access Journals (Sweden)

    Charles Ricardo L OPES

    2015-06-01

    Full Text Available The aim of this study was to evaluate the effects of daily undulating training periodization designed for maximal lower limb muscle strength and sprint performance in under - 20 soccer players. Twenty - four male athletes (age = 19.1 ± 1.2 yr; mass = 71.1 ± 6. 8 kg; height = 178.0 ± 0.1 cm participated in four weeks of a daily undulating periodized (DUP training soccer program. During the pre - and post - training periods the subjects performed a one repetition maximum (1 RM half back squat test and a 15 - meter s print. Significant training - induced changes were observed in sprint times (pre = 2.38 ± 0.01 s; post = 2.31 ± 0.02 s and 1 RM tests (pre = 107.0 ± 2.0 kg; post = 128.0 ± 2.2 kg. These results indicate that a DUP program is efficient in promoting positive neuromuscular adaptations in soccer players, even with a short - term preseason training period.

  7. Call Center ist nicht gleich Call Center

    OpenAIRE

    Baumgartner, Marc; Udris, Ivars

    2005-01-01

    Untersuchungen in 14 Schweizer Call Centers erbrachten vier Call Center-Typen, die sich hinsichtlich Arbeitstätigkeiten und Kommunikationsrichtung voneinander unterscheiden: (a) Beratungs- und Beschwerdemanagement, (b) Informationsmanagement, (c) Auftragsmanagement und (d) Kunden- und Kampagnenmanagement. Dies hat auch Auswirkungen auf die Personalstruktur, -selektion und -entwicklung der Call Center. Es wird der Frage nachgegangen, welche Kompetenzanforderungen in den unterschiedlichen Call ...

  8. Children's cancer centers

    Science.gov (United States)

    Pediatric cancer center; Pediatric oncology center; Comprehensive cancer center ... Treating childhood cancer is not the same as treating adult cancer. The cancers are different. So are the treatments and the ...

  9. Womens Business Center

    Data.gov (United States)

    Small Business Administration — Women's Business Centers (WBCs) represent a national network of nearly 100 educational centers throughout the United States and its territories, which are designed...

  10. Plasma based helical undulator for controlled emission of circularly and elliptically polarised betatron radiationJ. Vieira, J. Martins, U. Sinha

    CERN Document Server

    Vieira, J; Sinha, U

    2016-01-01

    We explore a plasma based analogue of a helical undulator capable of providing circularly and elliptically polarised betatron radiation. We focus on ionisation injection configurations and in the conditions where the laser pulse driver can force collective betatron oscillations over the whole trapped electron bunch. With an analytical model and by employing three dimensional simulations and radiation calculations, we find that circularly or elliptically polarised laser drivers can force helical betatron oscillations, which produce circularly/elliptically polarised betatron x-rays. We assess the level of polarisation numerically and analytically, and find that the number of circularly polarised photons can be controlled by tuning the laser pulse driver polarisation. We show the production of betatron radiation that is circularly polarised up to < 40% close to regions of maximum photon flux. The total flux of circularly polarised betatron radiation drops for elliptically polarised drivers, and is negligible ...

  11. Scattering of Surface Waves by the Edge of a Small Undulation on a Porous Bed in an Ocean with Ice-cover

    Institute of Scientific and Technical Information of China (English)

    Smrutiranjan Mohapatra

    2014-01-01

    Scattering of surface waves by the edge of a small undulation on a porous bed in an ocean of finite depth, where the free surface has an ice-cover being modelled as an elastic plate of very small thickness, is investigated within the framework of linearized water wave theory. The effect of surface tension at the surface below the ice-cover is neglected. There exists only one wave number propagating at just below the ice-cover. A perturbation analysis is employed to solve the boundary value problem governed by Laplace's equation by a method based on Green's integral theorem with the introduction of appropriate Green's function and thereby evaluating the reflection and transmission coefficients approximately up to first order. A patch of sinusoidal ripples is considered as an example and the related coefficients are determined.

  12. Student Success Center Toolkit

    Science.gov (United States)

    Jobs For the Future, 2014

    2014-01-01

    "Student Success Center Toolkit" is a compilation of materials organized to assist Student Success Center directors as they staff, launch, operate, and sustain Centers. The toolkit features materials created and used by existing Centers, such as staffing and budgeting templates, launch materials, sample meeting agendas, and fundraising…

  13. Day Care Centers

    Data.gov (United States)

    Department of Homeland Security — This database contains locations of day care centers for 50 states and Washington D.C. and Puerto Rico. The dataset only includes center based day care locations...

  14. Poison Control Centers

    Science.gov (United States)

    ... 1222 immediately. Name State American Association of Poison Control Centers Address AAPCC Central Office NOT A POISON ... not for emergency use. Arkansas ASPCA Animal Poison Control Center Address 1717 S. Philo Road, Suite 36 Urbana, ...

  15. New Mexico Convention Centers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This dataset provides an initial version of the locations of convention centers in New Mexico, in point form, with limited attributes, compiled using available data...

  16. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Education / Safety Education Centers En Español Carbon Monoxide Information Center The Invisible Killer Carbon monoxide, also known ... Install one and check its batteries regularly. View Information About CO Alarms Other CO Topics Safety Tips ...

  17. Hydrologic Engineering Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Hydrologic Engineering Center (HEC), an organization within the Institute for Water Resources, is the designated Center of Expertise for the U.S. Army Corps of...

  18. RSW Cell Centered Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — New cell centered grids are generated to complement the node-centered ones uploaded. Six tarballs containing the coarse, medium, and fine mixed-element and pure...

  19. Tornadoes: A Center Approach.

    Science.gov (United States)

    Christman-Rothlein, Liz; Meinbach, Anita M.

    1981-01-01

    Information is given on how to put together a learning center. Discusses information and activity packets for a complete learning center on tornadoes including objectives, directions, materials, photographs of physical arrangements, and posttest. (DC)

  20. BKG Data Center

    Science.gov (United States)

    Thorandt, Volkmar; Wojdziak, Reiner

    2013-01-01

    This report summarizes the activities and background information of the IVS Data Center for the year 2012. Included is information about functions, structure, technical equipment, and staff members of the BKG Data Center.

  1. ACTS data center

    Science.gov (United States)

    Syed, Ali; Vogel, Wolfhard J.

    1993-01-01

    Viewgraphs on ACTS Data Center status report are included. Topics covered include: ACTS Data Center Functions; data flow overview; PPD flow; RAW data flow; data compression; PPD distribution; RAW Data Archival; PPD Audit; and data analysis.

  2. NIH Clinical Centers

    Data.gov (United States)

    Federal Laboratory Consortium — The NIH Clinical Center consists of two main facilities: The Mark O. Hatfield Clinical Research Center, which opened in 2005, houses inpatient units, day hospitals,...

  3. Center for Functional Nanomaterials

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Functional Nanomaterials (CFN) explores the unique properties of materials and processes at the nanoscale. The CFN is a user-oriented research center...

  4. BIOMASS, FLUORESCENCE and species abundance tows - undulating tow and tows data collected in the North Pacific Ocean on the NEW HORIZON, RANGE RECOVERER and THOMAS G. THOMPSON cruises NH0005, NH0007 and others as part of the NEP project from 2000-05-30 to 2002-08-16 (NODC Accession 0114240)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0114240 includes tows - undulating tow, tows and biological data collected aboard the NEW HORIZON, RANGE RECOVERER and THOMAS G. THOMPSON during...

  5. CHLOROPHYLL A, SALINITY, HYDROSTATIC PRESSURE, DISSOLVED OXYGEN and other undulating profile data collected in the North Atlantic Ocean on the ENDEAVOR cruises EN321 and EN325 as part of the GB project from 1999-03-30 to 1999-06-27 (NODC Accession 0106340)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0106340 includes profile, undulating profile, biological, chemical and physical data collected aboard the ENDEAVOR during cruises EN321 and EN325 in...

  6. SALINITY, HYDROSTATIC PRESSURE, TEMPERATURE, FLUORESCENCE and SIGMA-T undulating profile data collected in the North Atlantic Ocean on the OCEANUS cruise OC342 as part of the GB project from 1999-05-21 to 1999-06-04 (NODC Accession 0104401)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0104401 includes profile, undulating profile, biological and physical data collected aboard the OCEANUS during cruise OC342 in the North Atlantic...

  7. TEMPERATURE, FLUORESCENCE, LIGHT TRANSMISSION, SIGMA-T and other undulating profile data collected in the North Atlantic Ocean on the OCEANUS cruises OC340 and OC343 as part of the GB project from 1999-03-30 to 1999-06-30 (NODC Accession 0106732)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0106732 includes profile, undulating profile, biological and physical data collected aboard the OCEANUS during cruises OC340 and OC343 in the North...

  8. Center of buoyancy definition

    International Nuclear Information System (INIS)

    The center of buoyancy of an arbitrary shaped body is defined in analogy to the center of gravity. The definitions of the buoyant force and center of buoyancy in terms of integrals over the area of the body are converted to volume integrals and shown to have simple intuitive interpretations

  9. DC method experiments in undulating earth's surface physical model made by plastic%利用橡皮泥制作起伏地表物理模型进行直流电法实验

    Institute of Scientific and Technical Information of China (English)

    梁铁成; 孙建国; 孙章庆

    2013-01-01

    It is difficult to obtain the result of DC method experiments in the undulating earth's surface condition in that it always needs to do these experiments in the sink. Although the undulating earth's surface model can be made by sand or soil, they both have their own shortcomings. So plasticine to set up the undulating earth' s surface models is used and a straightforward experimental scheme in these models for the future laboratory DC method experiments is presented.%目前室内直流电法实验大都在水槽里进行,所以要想得到起伏地表的实验结果是很难的.尽管土和沙子可以制作成起伏地表模型,但是都有各自的优缺点.采用橡皮泥制作模型实现了起伏地表的实验,为今后在室内进行直流电法实验找到了一种简单易行的方法.

  10. Characteristics of a miniature parallel-plate free-air ionization chamber for measuring the intensity of synchrotron radiation from an undulator

    Science.gov (United States)

    Nariyama, Nobuteru

    2004-09-01

    In order to develop an absolute intensity monitor for synchrotron radiation from an undulator, the characteristics of a parallel-plate free-air ionization chamber with a plate separation of 4.2 mm, which was considered to be as narrow as possible, were investigated using 8-30 keV monoenergetic photons at SPring-8. Using a Si-PIN photodiode as the reference monitor, saturation was confirmed at 8-30 keV at a photon intensity of an order of 1013 photons/s. The collection efficiency became almost unity at 8 and 10 keV within 3.8% and 1.1%, respectively, which gradually decreased with increasing energy and attained 0.52 at 30 keV because some of the high-energy electrons escaped from the sensitive volume. When the pair of electrodes was transferred from the upper and lower sides to the left and right sides of the beam axis in order to investigate the influence of linear polarization of synchrotron radiation, a decrease in the collection efficiency was observed. Monte Carlo simulations considering linear polarization showed that the plate separation required for no electron loss was 26, 14, and 8 mm for 30, 20, and 15 keV photons, respectively. For 20 keV photons, saturation characteristics were investigated using an ionization chamber with 14 mm plate separation.

  11. X-ray photon beam diagnostics devices for the commissioning and user operation of the multi-undulator facility European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Gruenert, Jan; Ozkan, Cigdem; Li, Bin; Freund, Wolfgang; Buck, Jens; Molodtsov, Serguei [European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany)

    2012-07-01

    The X-ray Free-Electron-Lasers (XFELs) LCLS, SACLA, and the European XFEL open new opportunities in the research of very small structures and at the same time extremely fast phenomena (Aangstroem and femtosecond resolution). Unlike pulses from a conventional laser radiation is here created by Self-Amplified Spontaneous Emission when electron bunches pass through very long segmented undulators. Shot noise at the origin of this process leads to pulse-to-pulse variations of intensity, spectrum, wavefront, etc. Any XFEL diagnostics is susceptible to single-shot damage due to the extreme brilliance. Apart from the large facility energy range (280 eV to 25 keV), the particular challenge for the European XFEL diagnostics is the 4.5 MHz intra-bunch train repetition rate, causing additional damage by high heat loads and making shot-to-shot diagnostics very demanding. We report on concepts, developments, and compromises between resolution/accuracy and energy range/shot-to-shot capabilities.

  12. Relativistic Guiding Center Equations

    Energy Technology Data Exchange (ETDEWEB)

    White, R. B. [PPPL; Gobbin, M. [Euratom-ENEA Association

    2014-10-01

    In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.

  13. Chemical Security Analysis Center

    Data.gov (United States)

    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  14. Surgery center joint ventures.

    Science.gov (United States)

    Zasa, R J

    1999-01-01

    Surgery centers have been accepted as a cost effective, patient friendly vehicle for delivery of quality ambulatory care. Hospitals and physician groups also have made them the vehicles for coming together. Surgery centers allow hospitals and physicians to align incentives and share benefits. It is one of the few types of health care businesses physicians can own without anti-fraud and abuse violation. As a result, many surgery center ventures are now jointly owned by hospitals and physician groups. This article outlines common structures that have been used successfully to allow both to own and govern surgery centers.

  15. Electron Microscopy Center (EMC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

  16. Test Control Center (TCC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Test Control Center (TCC) provides a consolidated facility for planning, coordinating, controlling, monitoring, and analyzing distributed test events. ,The TCC...

  17. Center for Deployment Psychology

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Deployment Psychology was developed to promote the education of psychologists and other behavioral health specialists about issues pertaining to the...

  18. Airline Operation Center Workstation

    Data.gov (United States)

    Department of Transportation — The Airline Operation Center Workstation (AOC Workstation) represents equipment available to users of the National Airspace system, outside of the FAA, that enables...

  19. Environmental Modeling Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...

  20. Data Center at NICT

    Science.gov (United States)

    Ichikawa, Ryuichi; Sekido, Mamoru

    2013-01-01

    The Data Center at the National Institute of Information and Communications Technology (NICT) archives and releases the databases and analysis results processed at the Correlator and the Analysis Center at NICT. Regular VLBI sessions of the Key Stone Project VLBI Network were the primary objective of the Data Center. These regular sessions continued until the end of November 2001. In addition to the Key Stone Project VLBI sessions, NICT has been conducting geodetic VLBI sessions for various purposes, and these data are also archived and released by the Data Center.

  1. Small Business Development Center

    Data.gov (United States)

    Small Business Administration — Small Business Development Centers (SBDCs) provide assistance to small businesses and aspiring entrepreneurs throughout the United States and its territories. SBDCs...

  2. The Undulating Spiral Motion of Celestial Bodies in Solar System Relative to a Certain Point on the Earth(III)---the Stereoscopic Superposition and Simulation Analysis of Undulating Spiral%太阳系天体相对地球某点的波动式螺线运动(Ⅲ)--波动式螺线立体叠加及模拟分析

    Institute of Scientific and Technical Information of China (English)

    李嘉; 张勇军; 李钦豪; 李琳

    2014-01-01

    在«太阳系天体相对地球某点的波动式螺线运动(I)»和«太阳系天体相对地球某点的波动式螺线运动(II)»中,推导太阳系天体对地球某点的波动式螺线运动方程。对螺线方程进行分析,并根据傅里叶原理,将各波动方程叠加,并以太阳系天体对地球赤道某点波动式螺线运动方程为例,利用计算机模拟得到各叠加图线,以探讨太阳系天体运动对地球某点的共同影响。模拟结果表明,太阳系天体对地球赤道某点立体波动式螺线叠加后,波形与单个天体类似,仍呈周期性螺线变化,且在三个坐标平面上的投影均为周期性波动,整体传播呈现薄膜状波动面。日月叠加图线与太阳近似,五大行星叠加图线较七大行星规则,五大行星在双波动坐标轴下的波动式螺线叠加在 yz平面的投影在某个阶段非常的密集,之后突然稀疏,七大行星也是,不过五大行星的密集长度比七大行星的长。日月对太阳系行星总体叠加影响不大。%In the thesis of The Undulating Spiral Motion of Celestial Bodies in Solar System Relative to a Certain Point on the Earth (I )and The Undulating Spiral Motion of Celestial Bodies in Solar System Relative to a Certain Point on the Earth (I I ),undulating spiral motion equation of solar system bodies relative to a certain point on the earth has been derived.This thesis will analyze each equation and superimpose the undulating equation based on the Fourier Principle,and then taking the undulating spiral motion equation of solar system bodies relative to a certain point on terrestrial equator for example,use computers simulation to obtain superposition graph to research the common influence of solar system bodies to a certain point on the earth.The simulation result indicates that,after superimposing the stereoscopic undulating spiral of solar system bodies relative to a certain point on terrestrial equator

  3. Funding Opportunity: Genomic Data Centers

    Science.gov (United States)

    Funding Opportunity CCG, Funding Opportunity Center for Cancer Genomics, CCG, Center for Cancer Genomics, CCG RFA, Center for cancer genomics rfa, genomic data analysis network, genomic data analysis network centers,

  4. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Consumers Businesses Contact CPSC Website Design Feedback Consumers: Español Businesses: Español , 中文 , Tiếng Việt Connect with Us : Twitter YouTube ... Safely Home / Safety Education / Safety Education Centers En Español Carbon Monoxide Information Center The Invisible Killer Carbon ...

  5. Technology Information Center

    International Nuclear Information System (INIS)

    A Transportation Technology Center (TTC) has been established at Sandia to address the transportation of nuclear waste and spent fuel. The Technology Information Center (TIC) acts as TTC's clearing house for nuclear material transportation information. TIC's activities are divided into three activities: public information, policy information, and technical information. Some of the uses of TIC's activities are briefly outlined

  6. Center for Women Veterans

    Science.gov (United States)

    ... VA » Center for Women Veterans (CWV) Center for Women Veterans (CWV) 10/27/2016 #VeteranOfTheDay Army Veteran ... Meet the Veteran of the Day » Employment and Women Veterans An interview with the Women Veteran Program ...

  7. Call Center Capacity Planning

    DEFF Research Database (Denmark)

    Nielsen, Thomas Bang

    The main topics of the thesis are theoretical and applied queueing theory within a call center setting. Call centers have in recent years become the main means of communication between customers and companies, and between citizens and public institutions. The extensively computerized infrastructu...

  8. NASA propagation information center

    Science.gov (United States)

    Smith, Ernest K.; Flock, Warren L.

    1990-07-01

    The NASA Propagation Information Center became formally operational in July 1988. It is located in the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. The center is several things: a communications medium for the propagation with the outside world, a mechanism for internal communication within the program, and an aid to management.

  9. Simple Machine Science Centers

    Science.gov (United States)

    Chessin, Debby

    2007-01-01

    Science centers can engage students; accommodate different learning styles and individual interests; help students become independent and confident learners; and encourage social skills among students. In this article, the author worked with third-grade students as they completed activities at learning centers during a week-long unit on simple…

  10. Analysis of heat generation of lithium ion rechargeable batteries used in implantable battery systems for driving undulation pump ventricular assist device.

    Science.gov (United States)

    Okamoto, Eiji; Nakamura, Masatoshi; Akasaka, Yuhta; Inoue, Yusuke; Abe, Yusuke; Chinzei, Tsuneo; Saito, Itsuro; Isoyama, Takashi; Mochizuki, Shuichi; Imachi, Kou; Mitamura, Yoshinori

    2007-07-01

    We have developed internal battery systems for driving an undulation pump ventricular assist device using two kinds of lithium ion rechargeable batteries. The lithium ion rechargeable batteries have high energy density, long life, and no memory effect; however, rise in temperature of the lithium ion rechargeable battery is a critical issue. Evaluation of temperature rise by means of numerical estimation is required to develop an internal battery system. Temperature of the lithium ion rechargeable batteries is determined by ohmic loss due to internal resistance, chemical loss due to chemical reaction, and heat release. Measurement results of internal resistance (R(cell)) at an ambient temperature of 37 degrees C were 0.1 Omega in the lithium ion (Li-ion) battery and 0.03 Omega in the lithium polymer (Li-po) battery. Entropy change (DeltaS) of each battery, which leads to chemical loss, was -1.6 to -61.1 J/(mol.K) in the Li-ion battery and -9.6 to -67.5 J/(mol.K) in the Li-po battery depending on state of charge (SOC). Temperature of each lithium ion rechargeable battery under a discharge current of 1 A was estimated by finite element method heat transfer analysis at an ambient temperature of 37 degrees C configuring with measured R(cell) and measured DeltaS in each SOC. Results of estimation of time-course change in the surface temperature of each battery coincided with results of measurement results, and the success of the estimation will greatly contribute to the development of an internal battery system using lithium ion rechargeable batteries.

  11. Relative Lyapunov Center Bifurcations

    DEFF Research Database (Denmark)

    Wulff, Claudia; Schilder, Frank

    2014-01-01

    Relative equilibria (REs) and relative periodic orbits (RPOs) are ubiquitous in symmetric Hamiltonian systems and occur, for example, in celestial mechanics, molecular dynamics, and rigid body motion. REs are equilibria, and RPOs are periodic orbits of the symmetry reduced system. Relative Lyapunov...... center bifurcations are bifurcations of RPOs from REs corresponding to Lyapunov center bifurcations of the symmetry reduced dynamics. In this paper we first prove a relative Lyapunov center theorem by combining recent results on the persistence of RPOs in Hamiltonian systems with a symmetric Lyapunov...... center theorem of Montaldi, Roberts, and Stewart. We then develop numerical methods for the detection of relative Lyapunov center bifurcations along branches of RPOs and for their computation. We apply our methods to Lagrangian REs of the N-body problem....

  12. Energy efficient data centers

    Energy Technology Data Exchange (ETDEWEB)

    Tschudi, William; Xu, Tengfang; Sartor, Dale; Koomey, Jon; Nordman, Bruce; Sezgen, Osman

    2004-03-30

    Data Center facilities, prevalent in many industries and institutions are essential to California's economy. Energy intensive data centers are crucial to California's industries, and many other institutions (such as universities) in the state, and they play an important role in the constantly evolving communications industry. To better understand the impact of the energy requirements and energy efficiency improvement potential in these facilities, the California Energy Commission's PIER Industrial Program initiated this project with two primary focus areas: First, to characterize current data center electricity use; and secondly, to develop a research ''roadmap'' defining and prioritizing possible future public interest research and deployment efforts that would improve energy efficiency. Although there are many opinions concerning the energy intensity of data centers and the aggregate effect on California's electrical power systems, there is very little publicly available information. Through this project, actual energy consumption at its end use was measured in a number of data centers. This benchmark data was documented in case study reports, along with site-specific energy efficiency recommendations. Additionally, other data center energy benchmarks were obtained through synergistic projects, prior PG&E studies, and industry contacts. In total, energy benchmarks for sixteen data centers were obtained. For this project, a broad definition of ''data center'' was adopted which included internet hosting, corporate, institutional, governmental, educational and other miscellaneous data centers. Typically these facilities require specialized infrastructure to provide high quality power and cooling for IT equipment. All of these data center types were considered in the development of an estimate of the total power consumption in California. Finally, a research ''roadmap'' was developed

  13. User-centered design

    International Nuclear Information System (INIS)

    The simplification philosophy, as an example, that both of EPRI-URD and EUR emphasize is treated mostly for the cost reduction of the nuclear power plants, but not for the simplification of the structure of user's tasks, which is one of the principles of user-centered design. A user-centered design is a philosophy based on the needs and interests of the user, with an emphasis on making products usable and understandable. However, the nuclear power plants offered these days by which the predominant reactor vendors are hardly user-centered but still designer-centered or technology-centered in viewpoint of fulfilling user requirements. The main goal of user-centered design is that user requirements are elicited correctly, reflected properly into the system requirements, and verified thoroughly by the tests. Starting from the user requirements throughout to the final test, each requirement should be traceable. That's why requirement traceability is a key to the user-centered design, and main theme of a requirement management program, which is suggested to be added into EPRI-URD and EUR in the section of Design Process. (author)

  14. Lens auto-centering

    Science.gov (United States)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève; Tremblay, Mathieu

    2015-09-01

    In a typical optical system, optical elements usually need to be precisely positioned and aligned to perform the correct optical function. This positioning and alignment involves securing the optical element in a holder or mount. Proper centering of an optical element with respect to the holder is a delicate operation that generally requires tight manufacturing tolerances or active alignment, resulting in costly optical assemblies. To optimize optical performance and minimize manufacturing cost, there is a need for a lens mounting method that could relax manufacturing tolerance, reduce assembly time and provide high centering accuracy. This paper presents a patent pending lens mounting method developed at INO that can be compared to the drop-in technique for its simplicity while providing the level of accuracy close to that achievable with techniques using a centering machine (usually innovative auto-centering method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature and the thread angle of the retaining ring. The autocentering principle and centering test results performed on real optical assemblies are presented. In addition to the low assembly time, high centering accuracy, and environmental robustness, the INO auto-centering method has the advantage of relaxing lens and barrel bore diameter tolerances as well as lens wedge tolerances. The use of this novel lens mounting method significantly reduces manufacturing and assembly costs for high performance optical systems. Large volume productions would especially benefit from this advancement in precision lens mounting, potentially providing a drastic cost reduction.

  15. Fusion engineering design center

    International Nuclear Information System (INIS)

    In the spring of 1985, the Department of Energy (DOE) directed the Design Center to take a lead responsibility in assessing the engineering feasibility of a very compact tokamak experiment with copper coils. Following this assessment, the Design Center studied the Ignitor concept at the request of DOE and arrived at a design configuration. Many features of this configuration have been incorporated into the national baseline conceptual design for a Compact Ignition Tokamak (CIT). The Design Center continued to participate in the mirror program by contributing to the Minimars design effort, a two-year program to develop and describe an attractive tandem mirror reactor concept. The Design Center's principal role is in configuration definition of the candidate concepts. The Design Center continues to lead the engineering activities for the International Tokamak Reactor program. Advanced commercial tokamaks were studied by the Design Center as part of the Tokamak Power Systems Studies project coordinated by the DOE Office of Fusion Energy. The Design Center also provided design integration of the US effort. A cost accounting system that is applicable to all magnetic fusion reactor design studies was developed and applied to different confinement concepts and types of projects. The system provides the structure for development of a fusion cost database and validated cost estimating procedures

  16. Reliability Centered Maintenance - Methodologies

    Science.gov (United States)

    Kammerer, Catherine C.

    2009-01-01

    Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

  17. National Farm Medicine Center

    Science.gov (United States)

    Research Areas Applied Sciences Biomedical Informatics Clinical Research Epidemiology Farm Medicine Human Genetics Oral-Systemic Health Clinical ... Consulting Agritourism Farm MAPPER Lyme Disease ROPS Rebate Zika Virus National Farm Medicine Center The National Farm ...

  18. Cooperative Tagging Center (CTC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Cooperative Tagging Center (CTC) began as the Cooperative Game Fish Tagging Program (GTP) at Woods Hole Oceanographic Institute (WHOI) in 1954. The GTP was...

  19. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Chairman Commissioners Contact Information Agency Reports Legislative Affairs Job Opportunities Inspector General Safety Guides Safety Education Centers OnSafety Blog Neighborhood Safety Network Community Outreach ...

  20. FEMA Disaster Recovery Centers

    Data.gov (United States)

    Department of Homeland Security — This is a search site for FEMA's Disaster Recovery Centers (DRC). A DRC is a readily accessible facility or mobile office set up by FEMA where applicants may go for...

  1. Health Center Controlled Network

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Health Center Controlled Network (HCCN) tool is a locator tool designed to make data and information concerning HCCN resources more easily available to our...

  2. Centering in Japanese Discourse

    CERN Document Server

    Walker, M; Côté, S; Walker, Marilyn; Iida, Masayo; Cote, Sharon

    1996-01-01

    In this paper we propose a computational treatment of the resolution of zero pronouns in Japanese discourse, using an adaptation of the centering algorithm. We are able to factor language-specific dependencies into one parameter of the centering algorithm. Previous analyses have stipulated that a zero pronoun and its cospecifier must share a grammatical function property such as {\\sc Subject} or {\\sc NonSubject}. We show that this property-sharing stipulation is unneeded. In addition we propose the notion of {\\sc topic ambiguity} within the centering framework, which predicts some ambiguities that occur in Japanese discourse. This analysis has implications for the design of language-independent discourse modules for Natural Language systems. The centering algorithm has been implemented in an HPSG Natural Language system with both English and Japanese grammars.

  3. HUD Homeownership Centers

    Data.gov (United States)

    Department of Housing and Urban Development — HUD Homeownership Centers (HOCs) insure single family Federal Housing Administration (FHA) mortgages and oversee the selling of HUD homes. FHA has four...

  4. Accredited Birth Centers

    Science.gov (United States)

    ... 717-933-9743 Accredited since January 2016 100 Bright Eyes Midwifery and Wild Rivers Women's Health Accredited ... Birthing Center-Cedar Park Accredited 1130 Cottonwood Creek Trail Building D Suite 2 Cedar Park, TX 78613 ...

  5. ADVANCED DATA CENTER ECONOMY

    OpenAIRE

    Sukhov, R.; Amzarakov, M.; Isaev, E.

    2013-01-01

    The article addresses basic Data Centers (DC) drivers of price and engineering, which specify rules and price evaluation for creation and further operation. DC energy efficiency concept, its influence on DC initial price, operation costs and Total Cost of Ownership.

  6. National Automotive Center - NAC

    Data.gov (United States)

    Federal Laboratory Consortium — Encouraged by the advantages of collaboration, the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) worked with the Secretary of the...

  7. World Trade Center

    Index Scriptorium Estoniae

    2006-01-01

    Esilinastus katastroofifilm "World Trade Center" : stsenarist Andrea Berloff : režissöör Oliver Stone : kunstnik Jan Roelfs : osades Nicholas Cage, Michael Pena, Stephen Dorff jpt : Ameerika Ühendriigid 2006. Ka filmi prototüüpidest

  8. Center for Contaminated Sediments

    Data.gov (United States)

    Federal Laboratory Consortium — The U.S. Army Corps of Engineers Center for Contaminated Sediments serves as a clearinghouse for technology and expertise concerned with contaminated sediments. The...

  9. USU Patient Simulation Center

    Data.gov (United States)

    Federal Laboratory Consortium — he National Capital Area (NCA) Medical Simulation Center is a state-of-the-art training facility located near the main USU campus. It uses simulated patients (i.e.,...

  10. Center Innovation Fund Program

    Data.gov (United States)

    National Aeronautics and Space Administration — To stimulate and encourage creativity and innovation within the NASA Centers. The activities are envisioned to fall within the scope of NASA Space Technology or...

  11. Hazardous Waste Research Center

    Data.gov (United States)

    Federal Laboratory Consortium — A full-service research and evaluation center equipped with safety equipment, a high-bay pilot studies area, and a large-scale pilot studies facility The U.S. Army...

  12. Advanced Missile Signature Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Missile Signature Center (AMSC) is a national facility supporting the Missile Defense Agency (MDA) and other DoD programs and customers with analysis,...

  13. CNPC International Research Center

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ CNPC International Research Center (CNPCIRC), jointly managed by CNODC and RIPED of China National Petroleum Corporation (CNPC), was established in 1999 for providing technical research support to all the overseas oil and gas projects of CNPC.

  14. The Galactic Center

    OpenAIRE

    R. Genzel; Karas, V.

    2007-01-01

    In the past decade high resolution measurements in the infrared employing adaptive optics imaging on 10m telescopes have allowed determining the three dimensional orbits stars within ten light hours of the compact radio source at the center of the Milky Way. These observations show the presence of a three million solar mass black hole in Sagittarius A* beyond any reasonable doubt. The Galactic Center thus constitutes the best astrophysical evidence for the existence of black holes which have ...

  15. Oil Reserve Center Established

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Like other countries,China has started to grow its strategic oil reserve in case oil supplies are cut On December 18,2007,the National Development and Reform Commission(NDRC),China’s top economic planner,announced that the national oil reserve center has been officially launched.The supervisory system over the oil reserves has three levels: the energy department of the NDRC,the oil reserve center,and the reserve bases.

  16. Brownian Motion, "Diverse and Undulating"

    CERN Document Server

    Duplantier, Bertrand

    2016-01-01

    We describe in detail the history of Brownian motion, as well as the contributions of Einstein, Sutherland, Smoluchowski, Bachelier, Perrin and Langevin to its theory. The always topical importance in physics of the theory of Brownian motion is illustrated by recent biophysical experiments, where it serves, for instance, for the measurement of the pulling force on a single DNA molecule. In a second part, we stress the mathematical importance of the theory of Brownian motion, illustrated by two chosen examples. The by-now classic representation of the Newtonian potential by Brownian motion is explained in an elementary way. We conclude with the description of recent progress seen in the geometry of the planar Brownian curve. At its heart lie the concepts of conformal invariance and multifractality, associated with the potential theory of the Brownian curve itself.

  17. UCSF Center for HIV Information

    Science.gov (United States)

    ... Program For providers and patients VA National Viral Hepatitis Program For providers and patients TARGET Center Technical assistance tools for the Ryan White Community AETC National Resource Center Education and training for clinicians UCSF-Gladstone Center for ...

  18. International Water Center

    Science.gov (United States)

    The urban district of Nancy and the Town of Nancy, France, have taken the initiative of creating an International Center of Water (Centre International de l'Eau à Nancy—NAN.C.I.E.) in association with two universities, six engineering colleges, the Research Centers of Nancy, the Rhine-Meuse Basin Agency, and the Chamber of Commerce and Industry. The aim of this center is to promote research and technology transfer in the areas of water and sanitation. In 1985 it will initiate a research program drawing on the experience of 350 researchers and engineers of various disciplines who have already been assigned to research in these fields. The research themes, the majority of which will be multidisciplinary, concern aspects of hygiene and health, the engineering of industrial processes, water resources, and the environment and agriculture. A specialist training program offering five types of training aimed at university graduates, graduates of engineering colleges, or experts, will start in October 1984.

  19. Patient-centered Care.

    Science.gov (United States)

    Reynolds, April

    2009-01-01

    Patient-centered care focuses on the patient and the individual's particular health care needs. The goal of patient-centered health care is to empower patients to become active participants in their care. This requires that physicians, radiologic technologists and other health care providers develop good communication skills and address patient needs effectively. Patient-centered care also requires that the health care provider become a patient advocate and strive to provide care that not only is effective but also safe. For radiologic technologists, patient-centered care encompasses principles such as the as low as reasonably achievable (ALARA) concept and contrast media safety. Patient-centered care is associated with a higher rate of patient satisfaction, adherence to suggested lifestyle changes and prescribed treatment, better outcomes and more cost-effective care. This article is a Directed Reading. Your access to Directed Reading quizzes for continuing education credit is determined by your area of interest. For access to other quizzes, go to www.asrt.org/store. According to one theory, most patients judge the quality of their healthcare much like they rate an airplane flight. They assume that the airplane is technically viable and is being piloted by competent people. Criteria for judging a particular airline are personal and include aspects like comfort, friendly service and on-time schedules. Similarly, patients judge the standard of their healthcare on nontechnical aspects, such as a healthcare practitioner's communication and "soft skills." Most are unable to evaluate a practitioner's level of technical skill or training, so the qualities they can assess become of the utmost importance in satisfying patients and providing patient-centered care.(1). PMID:19901351

  20. Center for Botanical Interaction Studies

    Data.gov (United States)

    Federal Laboratory Consortium — Research Area: Dietary Supplements, Herbs, Antioxidants Program:Centers for Dietary Supplements Research: Botanicals Description:This center will look at safety and...

  1. User Centered Design

    DEFF Research Database (Denmark)

    Egbert, Maria; Matthews, Ben

    2012-01-01

    The interdisciplinary approach of User Centered Design is presented here with a focus on innovation in the design and use of hearing technologies as well as on the potential of innovation in interaction. This approach is geared towards developing new products, systems, technologies and practices...... based on an understanding of why so few persons with hearing loss use the highly advanced hearing technologies. In integrating Conversation Analysis (“CA”), audiology and User Centered Design, three disciplines which are collaborating together for the first time, we are addressing the following...

  2. QUAD FAMILY CENTERING.

    Energy Technology Data Exchange (ETDEWEB)

    PINAYEV, I.

    2005-11-01

    It is well known that beam position monitors (BPM) utilizing signals from pickup electrodes (PUE) provide good resolution and relative accuracy. The absolute accuracy (i.e. position of the orbit in the vacuum chamber) is not very good due to the various reasons. To overcome the limitation it was suggested to use magnetic centers of quadrupoles for the calibration of the BPM [1]. The proposed method provides accuracy better then 200 microns for centering of the beam position monitors using modulation of the whole quadrupole family.

  3. Lied Transplant Center

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Department of Energy has prepared an Environmental Assessment (DOE/EA-1143) evaluating the construction, equipping and operation of the proposed Lied Transplant Center at the University of Nebraska Medical Center in Omaha, Nebraska. Based on the analysis in the EA, the DOE has determined that the proposed action does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an Environmental Statement in not required.

  4. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  5. User-Centered Design through Learner-Centered Instruction

    Science.gov (United States)

    Altay, Burçak

    2014-01-01

    This article initially demonstrates the parallels between the learner-centered approach in education and the user-centered approach in design disciplines. Afterward, a course on human factors that applies learner-centered methods to teach user-centered design is introduced. The focus is on three tasks to identify the application of theoretical and…

  6. Economics of data center optics

    Science.gov (United States)

    Huff, Lisa

    2016-03-01

    Traffic to and from data centers is now reaching Zettabytes/year. Even the smallest of businesses now rely on data centers for revenue generation. And, the largest data centers today are orders of magnitude larger than the supercomputing centers of a few years ago. Until quite recently, for most data center managers, optical data centers were nice to dream about, but not really essential. Today, the all-optical data center - perhaps even an all-single mode fiber (SMF) data center is something that even managers of medium-sized data centers should be considering. Economical transceivers are the key to increased adoption of data center optics. An analysis of current and near future data center optics economics will be discussed in this paper.

  7. Starting a sleep center.

    Science.gov (United States)

    Epstein, Lawrence J; Valentine, Paul S

    2010-05-01

    The demand for sleep medicine services has grown tremendously during the last decade and will likely continue. To date, growth in demand has been met by growth in the number of new sleep centers. The need for more new centers will be dependent on market drivers that include increasing regulatory requirements, personnel shortages, integration of home sleep testing, changes in reimbursement, a shift in emphasis from diagnostics to treatment, and an increased consumer focus on sleep. The decision to open a new center should be based on understanding the market dynamics, completing a market analysis, and developing a business plan. The business plan should include an overview of the facility, a personnel and organizational structure, an evaluation of the business environment, a financial plan, a description of services provided, and a strategy for obtaining, managing, and extending a referral base. Implementation of the business plan and successful operation require ongoing planning and monitoring of operational parameters. The need for new sleep centers will likely continue, but the shifting market dynamics indicate a greater need for understanding the marketplace and careful planning. PMID:20442123

  8. INTERMOUNTAIN INDUSTRIAL ASSESSMENT CENTER

    Energy Technology Data Exchange (ETDEWEB)

    MELINDA KRAHENBUHL

    2010-05-28

    The U. S. Department of Energy’s Intermountain Industrial Assessment Center (IIAC) at the University of Utah has been providing eligible small- and medium-sized manufacturers with no-cost plant assessments since 2001, offering cost-effective recommendations for improvements in the areas of energy efficiency, pollution prevention, and productivity improvement.

  9. The Rural Information Center.

    Science.gov (United States)

    John, Patricia La Caille

    1989-01-01

    Describes the events that led to the creation of the Rural Information Center (RIC), a joint venture between the Extension Service and the National Agricultural Library to provide information to government officials involved in rural development. The databases accessed by RIC are described, and plans for a gateway system and network of all…

  10. Carolinas Energy Career Center

    Energy Technology Data Exchange (ETDEWEB)

    Classens, Anver; Hooper, Dick; Johnson, Bruce

    2013-03-31

    Central Piedmont Community College (CPCC), located in Charlotte, North Carolina, established the Carolinas Energy Career Center (Center) - a comprehensive training entity to meet the dynamic needs of the Charlotte region's energy workforce. The Center provides training for high-demand careers in both conventional energy (fossil) and renewable energy (nuclear and solar technologies/energy efficiency). CPCC completed four tasks that will position the Center as a leading resource for energy career training in the Southeast: • Development and Pilot of a New Advanced Welding Curriculum, • Program Enhancement of Non-Destructive Examination (NDE) Technology, • Student Support through implementation of a model targeted toward Energy and STEM Careers to support student learning, • Project Management and Reporting. As a result of DOE funding support, CPCC achieved the following outcomes: • Increased capacity to serve and train students in emerging energy industry careers; • Developed new courses and curricula to support emerging energy industry careers; • Established new training/laboratory resources; • Generated a pool of highly qualified, technically skilled workers to support the growing energy industry sector.

  11. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Flickr SlideShare All Pages & Documents Recalls & News Releases Home Recalls CPSC Recall API Recall Lawsuits Recalls by ... CO Poster Contest Toy Recall Statistics Pool Safely Home / Safety Education / Safety Education Centers En Español Carbon ...

  12. DISABILITY STATISTICS CENTER

    Science.gov (United States)

    The purpose of the Disability Statistics Center is to produce and disseminate statistical information on disability and the status of people with disabilities in American society and to establish and monitor indicators of how conditions are changing over time to meet their health...

  13. Memorial Alexander Center

    Directory of Open Access Journals (Sweden)

    AECK Associates, Arquitectos

    1958-05-01

    Full Text Available En Atlanta, el Instituto Tecnológico de Georgia acaba de ampliar sus instalaciones deportivas, construyendo el Alexander Memorial Center. Consta este nuevo Centro de dos edificios: una pista de baloncesto cubierta y un edificio anejo con vestuarios, duchas, una pista de entrenamiento, equipos técnicos y la emisora de radio Georgia Tech W. G. S. T.

  14. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... an Unsafe Product Consumers Businesses Contact CPSC Website Design Feedback Consumers: Español Businesses: Español , 中文 , Tiếng Việt ... Chairman Commissioners Contact Information Agency Reports Legislative Affairs Job Opportunities Inspector General Safety Guides Safety Education Centers ...

  15. Precision Joining Center

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.W.; Westphal, D.A.

    1991-08-01

    A workshop to obtain input from industry on the establishment of the Precision Joining Center (PJC) was held on July 10--12, 1991. The PJC is a center for training Joining Technologists in advanced joining techniques and concepts in order to promote the competitiveness of US industry. The center will be established as part of the DOE Defense Programs Technology Commercialization Initiative, and operated by EG G Rocky Flats in cooperation with the American Welding Society and the Colorado School of Mines Center for Welding and Joining Research. The overall objectives of the workshop were to validate the need for a Joining Technologists to fill the gap between the welding operator and the welding engineer, and to assure that the PJC will train individuals to satisfy that need. The consensus of the workshop participants was that the Joining Technologist is a necessary position in industry, and is currently used, with some variation, by many companies. It was agreed that the PJC core curriculum, as presented, would produce a Joining Technologist of value to industries that use precision joining techniques. The advantage of the PJC would be to train the Joining Technologist much more quickly and more completely. The proposed emphasis of the PJC curriculum on equipment intensive and hands-on training was judged to be essential.

  16. vCenter troubleshooting

    CERN Document Server

    Mills, Chuck

    2015-01-01

    The book is designed for the competent vCenter administrator or anyone who is responsible for the vSphere environment. It can be used as a guide by vSphere architects and VMware consultants for a successful vSphere solution. You should have good knowledge and an understanding of core elements and applications of the vSphere environment.

  17. American Overseas Research Centers Program

    Science.gov (United States)

    Office of Postsecondary Education, US Department of Education, 2012

    2012-01-01

    The American Overseas Research Centers Program provides grants to overseas research centers that are consortia of U.S. institutions of higher education to enable the centers to promote postgraduate research, exchanges, and area studies. Eligible applicants are those consortia of U.S. institutions of higher education centers that: (1) Receive more…

  18. Undulating Spiral Energy Field Theory of a Certain Point on the Earth and the Study on Spiral Growth Mechanism of Matter (Ⅱ)%地球上某点处波动式螺线能量场理论和物质的螺线生长机理研究(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    李嘉; 李琳; 张波; 张勇军; 李钦豪

    2014-01-01

    在«地球上某点处波动式螺线能量场理论和物质的螺线生长机理研究(Ⅰ)»一文中分析了太阳、月球、七大行星相对于地球上某点的理想波动式螺线运动轨迹。采用该轨迹作为太阳、月球、七大行星在地球上某点处波动式螺线能量场理论模型,并取用同样的修正方法。概括地球上某点处波动式螺线能量场模型的性质和波动属性,用地球上某点处波动式螺线能量场描述太阳系天体-地球引力场与光线场;分析波动式螺线引力场引力大小与方向;分析波动式螺线光线场,提出波动式螺线能量场螺线轨迹,其实为自然光能量的传播和获取路径;以地球上某点处波动式螺线能量场理论和模型分析金字塔结构、能量现象和自然光子的波动式螺线光线场的相关性。并分析了彩虹弯曲的原因,分析了生命形状与功能相关等自然现象。%The thesis of Undulating Spiral Energy Field Theory of a Certain Point on the Earth and the Study on Spiral Growth Mechanism of Matter (Ⅰ),has analyzed the ideal undulating spiral traj ectory of the sun,the moon and the other seven planets relative to a certain point on the earth.The ideal undulating spiral traj ectory as the theoretical model for undulating spiral energy field of the sun,the moon,and the other seven planets relative to a certain point on earth is used;we summarize the model and fluctuation property of undulating spiral energy field of a certain point on earth,using the undulating spiral energy field of a certain point on earth to describe the gravitational field and light field between solar system bodies and the earth;we also analyze the gravitation magnitude and direction of undulation spiral gravitational field,and undulating spiral light field,and we propose that spiral locus of undulating spiral energy field is actually the spread and access locus of natural light energy;the theory and model in the

  19. Application Center 2000

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ 在NET Enterprise Servers中,Application Center 2000扮演着企业管理电子商务分布式应用程序的重要角色.ApplicationCenter 2000是可以建立在Windows 2000上的网站应用程序,能够有效率地管理、降低企业成本.它也是一个向外拓展的技术,且通过丛集服务(Cluster Service),可随需求增加其扩展性与可用性,以此降低随之而来的高成本和管理方式,以及提供配置(Deploy)丛集服务器的能力.

  20. Entanglement with Centers

    CERN Document Server

    Ma, Chen-Te

    2015-01-01

    Entanglement is a physical phenomenon that each state cannot be described individually. Entanglement entropy gives quantitative understanding to the entanglement. We use decomposition of the Hilbert space to discuss properties of the entanglement. Therefore, partial trace operator becomes important to define the reduced density matrix from different centers, which commutes with all elements in the Hilbert space, corresponding to different entanglement choices or different observations on entangling surface. Entanglement entropy is expected to satisfy the strong subadditivity. We discuss decomposition of the Hilbert space for the strong subadditivity and other related inequalities. The entanglement entropy with centers can be computed from the Hamitonian formulations systematically, provided that we know wavefunctional. In the Hamitonian formulation, it is easier to obtain symmetry structure. We consider massless $p$-form theory as an example. The massless $p$-form theory in ($2p+2)$-dimensions has global symm...

  1. 4 Exhibition Centers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    China's convention and exhibition industry has grown rapidly in recent years, with some of the nation's key cities becoming hubs of internationally renowned expositions, spurred by the construction of new exhibition centers.In 2003, a total of 3,298 conventions and exhibitions were held in China, up from 3,075 in the previous year. The number is estimated to have hit 4,000 in 2004.

  2. COMPUTATIONAL SCIENCE CENTER

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT,J.

    2004-11-01

    The Brookhaven Computational Science Center brings together researchers in biology, chemistry, physics, and medicine with applied mathematicians and computer scientists to exploit the remarkable opportunities for scientific discovery which have been enabled by modern computers. These opportunities are especially great in computational biology and nanoscience, but extend throughout science and technology and include for example, nuclear and high energy physics, astrophysics, materials and chemical science, sustainable energy, environment, and homeland security.

  3. Solar Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Bob

    2011-04-27

    The Department of Energy, Golden Field Office, awarded a grant to the UNLV Research Foundation (UNLVRF) on August 1, 2005 to develop a solar and renewable energy information center. The Solar Technology Center (STC) is to be developed in two phases, with Phase I consisting of all activities necessary to determine feasibility of the project, including design and engineering, identification of land access issues and permitting necessary to determine project viability without permanently disturbing the project site, and completion of a National Environmental Policy Act (NEPA) Environmental Assessment. Phase II is the installation of infrastructure and related structures, which leads to commencement of operations of the STC. The STC is located in the Boulder City designated 3,000-acre Eldorado Valley Energy Zone, approximately 15 miles southwest of downtown Boulder City and fronting on Eldorado Valley Drive. The 33-acre vacant parcel has been leased to the Nevada Test Site Development Corporation (NTSDC) by Boulder City to accommodate a planned facility that will be synergistic with present and planned energy projects in the Zone. The parcel will be developed by the UNLVRF. The NTSDC is the economic development arm of the UNLVRF. UNLVRF will be the entity responsible for overseeing the lease and the development project to assure compliance with the lease stipulations established by Boulder City. The STC will be operated and maintained by University of Nevada, Las Vegas (UNLV) and its Center for Energy Research (UNLV-CER). Land parcels in the Eldorado Valley Energy Zone near the 33-acre lease are committed to the construction and operation of an electrical grid connected solar energy production facility. Other projects supporting renewable and solar technologies have been developed within the energy zone, with several more developments in the horizon.

  4. The MAGIC Data Center

    OpenAIRE

    Reichardt, Ignasi; Rico, Javier; Carmona, Emiliano; Contreras, Jose Luis; Cortina, Juan; Firpo, Roger; Font, Lluis; Moralejo, Abelardo; Nieto, Daniel; Oya, Igor; Reyes, Raquel de los

    2009-01-01

    The MAGIC I telescope produces currently around 100TByte of raw data per year that is calibrated and reduced on-site at the Observatorio del Roque de los Muchachos (La Palma). Since February 2007 most of the data have been stored and further processed in the Port d'Informacio Cientifica (PIC), Barcelona. This facility, which supports the GRID Tier 1 center for LHC in Spain, provides resources to give the entire MAGIC Collaboration access to the reduced telescope data. It is expected that the ...

  5. COMPUTATIONAL SCIENCE CENTER

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT, J.

    2005-11-01

    The Brookhaven Computational Science Center brings together researchers in biology, chemistry, physics, and medicine with applied mathematicians and computer scientists to exploit the remarkable opportunities for scientific discovery which have been enabled by modern computers. These opportunities are especially great in computational biology and nanoscience, but extend throughout science and technology and include, for example, nuclear and high energy physics, astrophysics, materials and chemical science, sustainable energy, environment, and homeland security. To achieve our goals we have established a close alliance with applied mathematicians and computer scientists at Stony Brook and Columbia Universities.

  6. Center for Beam Physics, 1992

    International Nuclear Information System (INIS)

    This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities

  7. National Center for Biotechnology Information

    Science.gov (United States)

    ... to NCBI Sign Out NCBI National Center for Biotechnology Information Search database All Databases Assembly BioProject BioSample ... Search Welcome to NCBI The National Center for Biotechnology Information advances science and health by providing access ...

  8. Contact Center Manager Administration (CCMA)

    Data.gov (United States)

    Social Security Administration — CCMA is the server that provides a browser-based tool for contact center administrators and supervisors. It is used to manage and configure contact center resources...

  9. Center for Beam Physics, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    This report contains the following information on the center for beam physics: Facilities; Organizational Chart; Roster; Profiles of Staff; Affiliates; Center Publications (1991--1993); and 1992 Summary of Activities.

  10. Oceans and Human Health Center

    Science.gov (United States)

    ... through a deeper understanding of the causes of ocean-related health threats About Find out more about our Center ... research taking place at the University of Miami Oceans & Human Health Center More Gallery Check out our photo and ...

  11. Italy INAF Data Center Report

    Science.gov (United States)

    Negusini, M.; Sarti, P.

    2013-01-01

    This report summarizes the activities of the Italian INAF VLBI Data Center. Our Data Center is located in Bologna, Italy and belongs to the Institute of Radioastronomy, which is part of the National Institute of Astrophysics.

  12. Dialysis centers - what to expect

    Science.gov (United States)

    ... what to expect; Renal replacement therapy - dialysis centers; End-stage renal disease - dialysis centers; Kidney failure - dialysis ... swells and the hand on that side feels cold Your hand gets cold, numb, or weak Also ...

  13. Patient-centered Radiology.

    Science.gov (United States)

    Itri, Jason N

    2015-10-01

    Patient-centered care (ie, care organized around the patient) is a model in which health care providers partner with patients and families to identify and satisfy patients' needs and preferences. In this model, providers respect patients' values and preferences, address their emotional and social needs, and involve them and their families in decision making. Radiologists have traditionally been characterized as "doctor-to-doctor" consultants who are distanced from patients and work within a culture that does not value patient centeredness. As medicine becomes more patient driven and the trajectory of health care is toward increasing patient self-reliance, radiologists must change the perception that they are merely consultants and become more active participants in patient care by embracing greater patient interaction. The traditional business model for radiology practices, which devalues interaction between patients and radiologists, must be transformed into a patient-centered model in which radiologists are reintegrated into direct patient care and imaging processes are reorganized around patients' needs and preferences. Expanding radiology's core assets to include direct patient care may be the most effective deterrent to the threat of commoditization. As the assault on the growth of Medicare spending continues, with medical imaging as a highly visible target, radiologists must adapt to the changing landscape by focusing on their most important consumer: the patient. This may yield substantial benefits in the form of improved quality and patient safety, reduced costs, higher-value care, improved patient outcomes, and greater patient and provider satisfaction. PMID:26466190

  14. Sustainable Biofuels Development Center

    Energy Technology Data Exchange (ETDEWEB)

    Reardon, Kenneth F. [Colorado State Univ., Fort Collins, CO (United States)

    2015-03-01

    The mission of the Sustainable Bioenergy Development Center (SBDC) is to enhance the capability of America’s bioenergy industry to produce transportation fuels and chemical feedstocks on a large scale, with significant energy yields, at competitive cost, through sustainable production techniques. Research within the SBDC is organized in five areas: (1) Development of Sustainable Crops and Agricultural Strategies, (2) Improvement of Biomass Processing Technologies, (3) Biofuel Characterization and Engine Adaptation, (4) Production of Byproducts for Sustainable Biorefining, and (5) Sustainability Assessment, including evaluation of the ecosystem/climate change implication of center research and evaluation of the policy implications of widespread production and utilization of bioenergy. The overall goal of this project is to develop new sustainable bioenergy-related technologies. To achieve that goal, three specific activities were supported with DOE funds: bioenergy-related research initiation projects, bioenergy research and education via support of undergraduate and graduate students, and Research Support Activities (equipment purchases, travel to attend bioenergy conferences, and seminars). Numerous research findings in diverse fields related to bioenergy were produced from these activities and are summarized in this report.

  15. The MAGIC Data Center

    CERN Document Server

    Reichardt, Ignasi; Carmona, Emiliano; Contreras, Jose Luis; Cortina, Juan; Firpo, Roger; Font, Lluis; Moralejo, Abelardo; Nieto, Daniel; Oya, Igor; Reyes, Raquel de los

    2009-01-01

    The MAGIC I telescope produces currently around 100TByte of raw data per year that is calibrated and reduced on-site at the Observatorio del Roque de los Muchachos (La Palma). Since February 2007 most of the data have been stored and further processed in the Port d'Informacio Cientifica (PIC), Barcelona. This facility, which supports the GRID Tier 1 center for LHC in Spain, provides resources to give the entire MAGIC Collaboration access to the reduced telescope data. It is expected that the data volume will increase by a factor 3 after the start-up of the second telescope, MAGIC II. The project to improve the MAGIC Data Center to meet these requirements is presented. In addition, we discuss the production of high level data products that will allow a more flexible analysis and will contribute to the international network of astronomical data (European Virtual Observatory). For this purpose, we will have to develop a new software able to adapt the analysis process to different data taking conditions, such as ...

  16. Core Research Center

    Science.gov (United States)

    Hicks, Joshua; Adrian, Betty

    2009-01-01

    The Core Research Center (CRC) of the U.S. Geological Survey (USGS), located at the Denver Federal Center in Lakewood, Colo., currently houses rock core from more than 8,500 boreholes representing about 1.7 million feet of rock core from 35 States and cuttings from 54,000 boreholes representing 238 million feet of drilling in 28 States. Although most of the boreholes are located in the Rocky Mountain region, the geologic and geographic diversity of samples have helped the CRC become one of the largest and most heavily used public core repositories in the United States. Many of the boreholes represented in the collection were drilled for energy and mineral exploration, and many of the cores and cuttings were donated to the CRC by private companies in these industries. Some cores and cuttings were collected by the USGS along with other government agencies. Approximately one-half of the cores are slabbed and photographed. More than 18,000 thin sections and a large volume of analytical data from the cores and cuttings are also accessible. A growing collection of digital images of the cores are also becoming available on the CRC Web site Internet http://geology.cr.usgs.gov/crc/.

  17. Sustainable Biofuels Development Center

    Energy Technology Data Exchange (ETDEWEB)

    SRIVASTAVA, PREM

    2015-03-02

    The mission of the Sustainable Bioenergy Development Center (SBDC) is to enhance the capability of America’s bioenergy industry to produce transportation fuels and chemical feedstocks on a large scale, with significant energy yields, at competitive cost, through sustainable production techniques. Research within the SBDC is organized in five areas: (1) Development of Sustainable Crops and Agricultural Strategies, (2) Improvement of Biomass Processing Technologies, (3) Biofuel Characterization and Engine Adaptation, (4) Production of Byproducts for Sustainable Biorefining, and (5) Sustainability Assessment, including evaluation of the ecosystem/climate change implication of center research and evaluation of the policy implications of widespread production and utilization of bioenergy. The overall goal of this project is to develop new sustainable bioenergy-related technologies. To achieve that goal, three specific activities were supported with DOE funds: bioenergy-related research initiation projects, bioenergy research and education via support of undergraduate and graduate students, and Research Support Activities (equipment purchases, travel to attend bioenergy conferences, and seminars). Numerous research findings in diverse fields related to bioenergy were produced from these activities and are summarized in this report.

  18. The Backgrounds Data Center

    Science.gov (United States)

    Snyder, W. A.; Gursky, H.; Heckathorn, H. M.; Lucke, R. L.; Berg, S. L.; Dombrowski, E. G.; Kessel, R. A.

    1993-01-01

    The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible.

  19. On chains of centered valuations

    Directory of Open Access Journals (Sweden)

    Rachid Chibloun

    2003-01-01

    Full Text Available We study chains of centered valuations of a domain A and chains of centered valuations of A [X1,…,Xn] corresponding to valuations of A. Finally, we make some applications to chains of valuations centered on the same ideal of A [X1,…,Xn] and extending the same valuation of A.

  20. CURRICULUM GUIDE, CHILD CARE CENTERS.

    Science.gov (United States)

    California State Dept. of Education, Sacramento.

    CALIFORNIA CHILD CARE CENTERS WERE ESTABLISHED IN 1943 TO SUPPLY SERVICES TO CHILDREN OF WORKING MOTHERS. THE CHILD CARE PROGRAM PROVIDES, WITHIN NURSERY AND SCHOOLAGE CENTERS, CARE AND EDUCATIONAL SUPERVISION FOR PRESCHOOL AND ELEMENTARY SCHOOL AGE CHILDREN. THE PHILOSOPHY OF THE CHILD CENTER PROGRAM IS BASED UPON THE BELIEF THAT EACH CHILD…

  1. COMPUTATIONAL SCIENCE CENTER

    Energy Technology Data Exchange (ETDEWEB)

    DAVENPORT, J.

    2006-11-01

    Computational Science is an integral component of Brookhaven's multi science mission, and is a reflection of the increased role of computation across all of science. Brookhaven currently has major efforts in data storage and analysis for the Relativistic Heavy Ion Collider (RHIC) and the ATLAS detector at CERN, and in quantum chromodynamics. The Laboratory is host for the QCDOC machines (quantum chromodynamics on a chip), 10 teraflop/s computers which boast 12,288 processors each. There are two here, one for the Riken/BNL Research Center and the other supported by DOE for the US Lattice Gauge Community and other scientific users. A 100 teraflop/s supercomputer will be installed at Brookhaven in the coming year, managed jointly by Brookhaven and Stony Brook, and funded by a grant from New York State. This machine will be used for computational science across Brookhaven's entire research program, and also by researchers at Stony Brook and across New York State. With Stony Brook, Brookhaven has formed the New York Center for Computational Science (NYCCS) as a focal point for interdisciplinary computational science, which is closely linked to Brookhaven's Computational Science Center (CSC). The CSC has established a strong program in computational science, with an emphasis on nanoscale electronic structure and molecular dynamics, accelerator design, computational fluid dynamics, medical imaging, parallel computing and numerical algorithms. We have been an active participant in DOES SciDAC program (Scientific Discovery through Advanced Computing). We are also planning a major expansion in computational biology in keeping with Laboratory initiatives. Additional laboratory initiatives with a dependence on a high level of computation include the development of hydrodynamics models for the interpretation of RHIC data, computational models for the atmospheric transport of aerosols, and models for combustion and for energy utilization. The CSC was formed to

  2. Citizen centered design

    Directory of Open Access Journals (Sweden)

    Ingrid Mulder

    2015-11-01

    Full Text Available Today architecture has to design for rapidly changing futures, in a citizen-centered way. That is, architecture needs to embrace meaningful design. Societal challenges ask for a new paradigm in city-making, which combines top-down public management with bottom-up social innovation to reach meaningful design. The biggest challenge is indeed to embrace a new collaborative attitude, a participatory approach, and to have the proper infrastructure that supports this social fabric. Participatory design and transition management are future-oriented, address people and institutions. Only through understanding people in context and the corresponding dynamics, one is able to design for liveable and sustainable urban environments, embracing the human scale.

  3. Interactive design center.

    Energy Technology Data Exchange (ETDEWEB)

    Pomplun, Alan R. (Sandia National Laboratories, Livermore, CA)

    2005-07-01

    Sandia's advanced computing resources provide researchers, engineers and analysts with the ability to develop and render highly detailed large-scale models and simulations. To take full advantage of these multi-million data point visualizations, display systems with comparable pixel counts are needed. The Interactive Design Center (IDC) is a second generation visualization theater designed to meet this need. The main display integrates twenty-seven projectors in a 9-wide by 3-high array with a total display resolution of more than 35 million pixels. Six individual SmartBoard displays offer interactive capabilities that include on-screen annotation and touch panel control of the facility's display systems. This report details the design, implementation and operation of this innovative facility.

  4. Mi Pueblo Food Center

    Directory of Open Access Journals (Sweden)

    Alexis A. Babb

    2016-04-01

    Full Text Available This case describes a current growth opportunity for Mi Pueblo Food Center, a Hispanic grocery chain with locations throughout the Bay Area, California. The CEO of Mi Pueblo is contemplating opening a new store location in East Palo Alto, CA, which has been without a local, full-service grocery store for over 20 years. Case objectives are for students to develop an understanding of how the grocery industry operates, the risks and opportunities associated with opening a new grocery store location, and the impact on social, environmental, and economic sustainability. The SWOT (Strengths, Weaknesses, Opportunities, Threats framework is used to analyze whether or not it is feasible for Mi Pueblo to open a new location in East Palo Alto. This case may be used with students in graduate and advanced undergraduate courses.

  5. Industrial Assessment Center Program

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Dereje Agonafer

    2007-11-30

    The work described in this report was performed under the direction of the Industrial Assessment Center (IAC) at University of Texas at Arlington. The IAC at The University of Texas at Arlington is managed by Rutgers University under agreement with the United States Department of Energy Office of Industrial Technology, which financially supports the program. The objective of the IAC is to identify, evaluate, and recommend, through analysis of an industrial plant’s operations, opportunities to conserve energy and prevent pollution, thereby reducing the associated costs. IAC team members visit and survey the plant. Based upon observations made in the plant, preventive/corrective actions are recommended. At all times we try to offer specific and quantitative recommendations of cost savings, energy conservation, and pollution prevention to the plants we serve.

  6. Concurrent engineering research center

    Science.gov (United States)

    Callahan, John R.

    1995-01-01

    The projects undertaken by The Concurrent Engineering Research Center (CERC) at West Virginia University are reported and summarized. CERC's participation in the Department of Defense's Defense Advanced Research Project relating to technology needed to improve the product development process is described, particularly in the area of advanced weapon systems. The efforts committed to improving collaboration among the diverse and distributed health care providers are reported, along with the research activities for NASA in Independent Software Verification and Validation. CERC also takes part in the electronic respirator certification initiated by The National Institute for Occupational Safety and Health, as well as in the efforts to find a solution to the problem of producing environment-friendly end-products for product developers worldwide. The 3M Fiber Metal Matrix Composite Model Factory Program is discussed. CERC technologies, facilities,and personnel-related issues are described, along with its library and technical services and recent publications.

  7. Supernova Science Center

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Woosley

    2008-05-05

    The Supernova Science Center (SNSC) was founded in 2001 to carry out theoretical and computational research leading to a better understanding of supernovae and related transients. The SNSC, a four-institutional collaboration, included scientists from LANL, LLNL, the University of Arizona (UA), and the University of California at Santa Cruz (UCSC). Intitially, the SNSC was funded for three years of operation, but in 2004 an opportunity was provided to submit a renewal proposal for two years. That proposal was funded and subsequently, at UCSC, a one year no-cost extension was granted. The total operational time of the SNSC was thus July 15, 2001 - July 15, 2007. This document summarizes the research and findings of the SNSC and provides a cummulative publication list.

  8. Data-analysis center

    International Nuclear Information System (INIS)

    Changes at the data analysis center are summarized. The most dramatic change in the operation of the Data-Analysis Center (DAC) has been the implementation of a VAX cluster. The cluster is a network of loosely coupled VAX computers tied together with a high-speed network and sharing common disks. System software was enhanced with the addition of DECalc, a spread-sheet program for the VAX. EUNICE, a UNIX environment package that is layered on VMS, was added to VAX machine MPFG0. Networking capabilities in the DAC were significantly increased during 1984. Specifically, access to remote networks, such as TELENET, was made easier through the C-Division computers. In addition, the DAC acquired dial-out modems and software so that users could transfer files between DAC machines and other computers over phone lines. A major project in the data-acquisition section in the past year was a special-purpose multiprocessor system to analyze data generated at LAMPF. During the year requirements for the system have been defined, hardware for a prototype system (PDP-11/730s and Ethernet) has been selected, and the system software has been designed. During 1984 both Q replay and data acquisition using VAXes and the VMS operating system were fully implemented and released to users. VAX data acquisition was used successfully in experiments at EPICS at LAMPF, at the Bates Linear Accelerator in Massachusetts, and at the Bevalac at Lawrence Berkeley National Laboratory. The EPICS VAX-11/730 system was upgraded to a VAX-11/750 at the end of 1984 to improve on-line response and performance. Another VAX-11/750 is being purchased for HRS

  9. Kennedy Space Center

    Science.gov (United States)

    Griffin, Amanda

    2012-01-01

    Among 2011's many accomplishments, we safely retired the Space Shuttle Program after 30 incredible years; completed the International Space Station and are taking steps to enable it to reach its full potential as a multi-purpose laboratory; and helped to expand scientific knowledge with missions like Aquarius, GRAIL, and the Mars Science Laboratory. Responding to national budget challenges, we are prioritizing critical capabilities and divesting ourselves of assets no longer needed for NASA's future exploration programs. Since these facilities do not have to be maintained or demolished, the government saves money. At the same time, our commercial partners save money because they do not have to build new facilities. It is a win-win for everyone. Moving forward, 2012 will be even more historically significant as we celebrate the 50th Anniversary of Kennedy Space Center. In the coming year, KSC will facilitate commercial transportation to low-Earth orbit and support the evolution of the Space Launch System and Orion crew vehicle as they ready for exploration missions, which will shape how human beings view the universe. While NASA's Vision is to lead scientific and technological advances in aeronautics and space for a Nation on the frontier of discovery KSC's vision is to be the world's preeminent launch complex for government and commercial space access, enabling the world to explore and work in space. KSC's Mission is to safely manage, develop, integrate, and sustain space systems through partnerships that enable innovative, diverse access to space and inspires the Nation's future explorers.

  10. Center for Neuroscience & Regenerative Medicine

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Neuroscience and Regenerative Medicine (CNRM) was established as a collaborative intramural federal program involving the U.S. Department of Defense...

  11. Consolidated Copayment Processing Center (CCPC)

    Data.gov (United States)

    Department of Veterans Affairs — The Consolidated Copayment Processing Center (CCPC) database contains Veteran patient contact and billing information in order to support the printing and mailing...

  12. Center for Environmental Health Sciences

    Data.gov (United States)

    Federal Laboratory Consortium — The primary research objective of the Center for Environmental Health Sciences (CEHS) at the University of Montana is to advance knowledge of environmental impacts...

  13. Energetics Manufacturing Technology Center (EMTC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Energetics Manufacturing Technology Center (EMTC), established in 1994 by the Office of Naval Research (ONR) Manufacturing Technology (ManTech) Program, is Navy...

  14. Satellite medical centers project

    Science.gov (United States)

    Aggarwal, Arvind

    2002-08-01

    World class health care for common man at low affordable cost: anywhere, anytime The project envisages to set up a national network of satellite Medical centers. Each SMC would be manned by doctors, nurses and technicians, six doctors, six nurses, six technicians would be required to provide 24 hour cover, each SMC would operate 24 hours x 7 days. It would be equipped with the Digital telemedicine devices for capturing clinical patient information and investigations in the form of voice, images and data and create an audiovisual text file - a virtual Digital patient. Through the broad band connectivity the virtual patient can be sent to the central hub, manned by specialists, specialists from several specialists sitting together can view the virtual patient and provide a specialized opinion, they can see the virtual patient, see the examination on line through video conference or even PCs, talk to the patient and the doctor at the SMC and controlle capturing of information during examination and investigations of the patient at the SMC - thus creating a virtual Digital consultant at the SMC. Central hub shall be connected to the doctors and consultants in remote locations or tertiary care hospitals any where in the world, thus creating a virtual hub the hierarchical system shall provide upgradation of knowledge to thedoctors in central hub and smc and thus continued medical education and benefit the patient thru the world class treatment in the smc located at his door step. SMC shall be set up by franchisee who shall get safe business opportunity with high returns, patients shall get Low cost user friendly worldclass health care anywhere anytime, Doctors can get better meaningful selfemplyment with better earnings, flexibility of working time and place. SMC shall provide a wide variety of services from primary care to world class Global consultation for difficult patients.

  15. ROSAT Science Data Center

    Science.gov (United States)

    Murray, Stephen; Pisarski, Ryszard L. (Technical Monitor)

    2001-01-01

    This report provides a summary of the Smithsonian Astrophysical Observatory (SAO) ROSAT SCIENCE DATA CENTER (RSDC) activities for the recent years of our contract. Details have already been reported in the monthly reports. The SAO was responsible for the High Resolution Imager (HRI) detector on ROSAT. We also provided and supported the HRI standard analysis software used in the pipeline processing (SASS). Working with our colleagues at the Max Planck in Garching Germany (MPE), we fixed bugs and provided enhancements. The last major effort in this area was the port from VMS/VAX to VMS/ALPHA architecture. In 1998, a timing bug was found in the HRI standard processing system which degraded the positional accuracy because events accessed incorrect aspect solutions. The bug was fixed and we developed off-line correction routines and provided them to the community. The Post Reduction Off-line Software (PROS) package was developed by SAO and runs in the IRAF environment. Although in recent years PROS was not a contractual responsibility of the RSDC, we continued to maintain the system and provided new capabilities such as the ability to deal with simulated AXAF data in preparation for the NASA call for proposals for Chandra. Our most recent activities in this area included the debugging necessary for newer versions of IRAF which broke some of our software. At SAO we have an operating version of PROS and hope to release a patch even though almost all functionality that was lost was subsequently recovered via an IRAF patch (i.e. most of our problems were caused by an IRAF bug).

  16. Design of a vacuum-compatible high-precision monochromatic beam-position monitor for use with synchrotron radiation from 5 to 25 keV.

    Science.gov (United States)

    Alkire, R W; Rosenbaum, G; Evans, G

    2000-03-01

    The Structural Biology Center beamline, 19ID, has been designed to take full advantage of the highly intense undulator radiation and very low source emittance available at the Advanced Photon Source. In order to keep the X-ray beam focused onto the pre-sample slits, a novel position-sensitive PIN diode array has been developed. The array consists of four PIN diodes positioned upstream of a 0.5 microm-thick metal foil placed in the X-ray beam. Using conventional difference-over-the-sum techniques, two-dimensional position information is obtained from the metal foil fluorescence. Because the full X-ray beam passes through the metal foil, the true beam center-of-mass is measured. The device is compact, inexpensive to construct, operates in a vacuum and has a working range of 8 mm x 10 mm that can be expanded with design modifications. Measured position sensitivity is 1-2 microm. Although optimized for use in the 5-25 keV energy range, the upper limit can be extended by changing metals or adjusting foil thickness. PMID:16609175

  17. Clean Energy Application Center

    Energy Technology Data Exchange (ETDEWEB)

    Freihaut, Jim

    2013-09-30

    The Mid Atlantic Clean Energy Application Center (MACEAC), managed by The Penn State College of Engineering, serves the six states in the Mid-Atlantic region (Pennsylvania, New Jersey, Delaware, Maryland, Virginia and West Virginia) plus the District of Columbia. The goals of the Mid-Atlantic CEAC are to promote the adoption of Combined Heat and Power (CHP), Waste Heat Recovery (WHR) and District Energy Systems (DES) in the Mid Atlantic area through education and technical support to more than 1,200 regional industry and government representatives in the region. The successful promotion of these technologies by the MACEAC was accomplished through the following efforts; (1)The MACEAC developed a series of technology transfer networks with State energy and environmental offices, Association of Energy Engineers local chapters, local community development organizations, utilities and, Penn State Department of Architectural Engineering alumni and their firms to effectively educate local practitioners about the energy utilization, environmental and economic advantages of CHP, WHR and DES; (2) Completed assessments of the regional technical and market potential for CHP, WHR and DE technologies application in the context of state specific energy prices, state energy and efficiency portfolio development. The studies were completed for Pennsylvania, New Jersey and Maryland and included a set of incentive adoption probability models used as a to guide during implementation discussions with State energy policy makers; (3) Using the technical and market assessments and adoption incentive models, the Mid Atlantic CEAC developed regional strategic action plans for the promotion of CHP Application technology for Pennsylvania, New Jersey and Maryland; (4) The CHP market assessment and incentive adoption model information was discussed, on a continuing basis, with relevant state agencies, policy makers and Public Utility Commission organizations resulting in CHP favorable incentive

  18. Danish Chinese Center for Nanometals

    DEFF Research Database (Denmark)

    Winther, Grethe

    The Danish-Chinese Center for Nanometals is funded by the Danish National Research Foundation and the National Natural Science Foundation of China. The Chinese partners in the Center are Institute of Metal Research in Shenyang, Tsinghua University and Chongqing University. The Danish part...

  19. Acoustic Center or Time Origin?

    DEFF Research Database (Denmark)

    Staffeldt, Henrik

    1999-01-01

    The paper discusses the acoustic center in relation to measurements of loudspeaker polar data. Also, it presents the related concept time origin and discusses the deviation that appears between positions of the acoustic center found by wavefront based and time based measuring methods....

  20. Learning Centers: Development and Operation.

    Science.gov (United States)

    Bennie, Frances

    There has been in recent years a growing acceptance of individualized learning concepts. Learning Centers have come to be viewed as an economical and viable strategy for accommodating diverse learning styles and needs. This book provides the educator with an understanding of the learning center concept, its origins, present manifestations, and…

  1. Pengembangan Model Manajemen ICT Center

    Directory of Open Access Journals (Sweden)

    Hakkun Elmunsyah

    2013-01-01

    Full Text Available Abstrak: Pengembangan Model Manajemen ICT Center. Kemendiknas telah melakukan investasi  cukup besar berupa pembangunan Jejaring komputer pendidikan nasional yang disebut Jaringan Pendidikan Nasional (Jardiknas, pada sekolah menengah kejuruan (SMK di seluruh Indonesia yang dikenal dengan nama ICT center. Penelitian ini bertujuan untuk menemukan model manajemen ICT center sesuai karakteristik SMK sehingga dapat memberikan kontribusi mutu pada SMK tersebut. Penelitian ini merupakan penelitian pengembangan atau Research and Development yang dikembangkan oleh Borg and Gall. Hasil secara keseluruhan penelitian menunjukkan berdasarkan uji coba keefektivan kinerja manajemen pada skala terbatas dan lebih luas menunjukkan bahwa model manajemen ICT center memenuhi kriteria sangat efektif. Kata-kata kunci: Jardiknas, SMK, model manajemen ICT center, kontribusi mutu

  2. 0.6-eV bandgap In0.69Ga0.31As thermophotovoltaic devices with compositionally undulating step-graded InAsyP1-ybuffers

    Institute of Scientific and Technical Information of China (English)

    Ji Lian; Lu Shu-Long; Jiang De-Sheng; Zhao Yong-Ming; Tan Ming; Zhu Ya-Qi; Dong Jian-Rong

    2013-01-01

    Single-junction,lattice-mismatched In0.69Ga0.31 As thermophotovoltaic (TPV) devices each with a bandgap of 0.6 eV are grown on InP substrate by metal-organic chemical vapour deposition (MOCVD).Compositionally undulating stepgraded InAsyPl-y buffer layers with a lattice mismatch of ~ 1.2% are used to mitigate the effect of lattice mismatch between the device layers and the InP substrate.With an optimized buffer thickness,the In0.69Ga0.31 As active layers grown on the buffer display a high crystal quality with no measurable tetragonal distortion.High-performance single-junction devices are demonstrated,with an open-circuit voltage of 0.215 V and a photovoltaic conversion efficiency of 6.9% at a short-circuit current density of 47.6 mA/cm2,which are measured under the standard solar simulator of air mass 1.5-global (AM 1.5 G).

  3. Análisis cortical de la cuenca Golfo de SanJorge utilizando anomalías de Bouguer y ondulaciones delgeoide Crustal analysis of the San Jorge Basin basedon Bouguer anomalies and geoid undulations

    Directory of Open Access Journals (Sweden)

    LauraL. Cornaglia

    2009-11-01

    Full Text Available Con la finalidad de evaluar características tales comotipo de corteza y estado isostático de la cuenca sedimentaria del Golfo de SanJorge, analizamos los valores observados de anomalías de Bouguer y deondulaciones geoidales calculadas desde anomalías de aire libre por el métodode fuentes equivalentes, comparándolos con las respuestas de un modelo decuenca compensado hidrostáticamente determinado a partir de la masa topográficade la zona y el relleno sedimentario de la cuenca. Por ambos caminosencontramos un exceso de masas que interpretamos como significativa antirraízcortical y predice subsidencia para el futuro. Otras alternativas como porejemplo la intrusión de densas masas intracorticales, no alteran lasconclusiones.Toevaluate crustal characteristics such as crust type and isostatic balance ofthe sedimentary San Jorge Gulf Basin, we analyzed observed Bouguer anomaliesand geoid undulations calculated from free-air anomalies and equivalentsources, comparing them with the responses of a hydrostatic compensated basinmodel prepared using the topographic mass of the area and the basin sedimentaryfill. In both cases we found an excess mass that we explained as a significantcrustal anti-root that predicts subsidence in the future. Others alternativesas for example the emplacement of dense intracrustal masses, do not modifiedthe conclusions.

  4. 0.6-eV bandgap In0.69Ga0.31As thermophotovoltaic devices with compositionally undulating step-graded InAsyP1−ybuffers

    International Nuclear Information System (INIS)

    Single-junction, lattice-mismatched In0.69Ga0.31As thermophotovoltaic (TPV) devices each with abandgap of 0.6 eV are grown on InP substrate by metal—organic chemical vapour deposition (MOCVD). Compositionally undulating step-graded InAsyP1−y buffer layers with a lattice mismatch of ∼1.2% are used to mitigate the effect of lattice mismatch between the device layers and the InP substrate. With an optimized buffer thickness, the In0.69Ga0.31As active layers grown on the buffer display a high crystal quality with no measurable tetragonal distortion. High-performance single-junction devices are demonstrated, with an open-circuit voltage of 0.215 V and a photovoltaic conversion efficiency of 6.9% at a short-circuit current density of 47.6 mA/cm2, which are measured underthe standard solar simulator of air mass 1.5-global (AM 1.5 G). (condensed matter: structural, mechanical, and thermal properties)

  5. A Study of Undulating Scale of Intonation in Declarative and Interrogative Sentences of Lemo Dialect%勒墨话陈述句和疑问句语调的起伏度研究

    Institute of Scientific and Technical Information of China (English)

    蔡希睿; 姚畅宜

    2016-01-01

    在语调格局的理论框架下,以归一化、相对化的方法分析云南省怒江傈僳族自治州泸水县洛本卓白族乡的4位勒墨(白族支系)发音人陈述句和疑问句的语调。实验通过语句调域和调群调域的考察,对比陈述句和疑问句语调的音高表现,得到勒墨话陈述句和疑问句语调的起伏度分布特征。%Under the theoretical framework of intonation pattern, this thesis adopts the methods of normali-zation and relativization to investigate the intonation of declarative and interrogative sentences in Lemo dialect spo-ken by four Lemo people ( a sub-branch of Bai) .Through the pitch representations of full range in sentence and sub-range in tone group, a comparison between the intonation in declarative and interrogative sentences is made and the distribution patterns of intonational undulating scale are found.

  6. Emergency Operations Center ribbon cutting

    Science.gov (United States)

    2009-01-01

    Center Director Gene Goldman and special guests celebrate the opening of the site's new Emergency Operations Center on June 2. Participants included (l t r): Steven Cooper, deputy director of the National Weather Service Southern Region; Tom Luedtke, NASA associate administrator for institutions and management; Charles Scales, NASA associate deputy administrator; Mississippi Gov. Haley Barbour; Gene Goldman, director of Stennis Space Center; Jack Forsythe, NASA assistant administrator for the Office of Security and Program Protection; Dr. Richard Williams, NASA chief health and medical officer; and Weldon Starks, president of Starks Contracting Company Inc. of Biloxi.

  7. Shopping Malls - ShoppingCenters

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Collected from a variety of sources both commercial and internal, this layer represents shopping center locations within Volusia County and is maintained by the...

  8. Human-Centered Design Capability

    Science.gov (United States)

    Fitts, David J.; Howard, Robert

    2009-01-01

    For NASA, human-centered design (HCD) seeks opportunities to mitigate the challenges of living and working in space in order to enhance human productivity and well-being. Direct design participation during the development stage is difficult, however, during project formulation, a HCD approach can lead to better more cost-effective products. HCD can also help a program enter the development stage with a clear vision for product acquisition. HCD tools for clarifying design intent are listed. To infuse HCD into the spaceflight lifecycle the Space and Life Sciences Directorate developed the Habitability Design Center. The Center has collaborated successfully with program and project design teams and with JSC's Engineering Directorate. This presentation discusses HCD capabilities and depicts the Center's design examples and capabilities.

  9. Poison control center - emergency number

    Science.gov (United States)

    ... ANYWHERE IN THE UNITED STATES This national hotline number will let you talk to experts in poisoning. ... centers in the United States use this national number. You should call if you have any questions ...

  10. Poison control center - emergency number

    Science.gov (United States)

    For a POISON EMERGENCY call: 1-800-222-1222 ANYWHERE IN THE UNITED STATES This national hotline number will let you ... is a free and confidential service. All local poison control centers in the United States use this ...

  11. FEMA Disaster Recovery Centers - KML

    Data.gov (United States)

    Department of Homeland Security — This is a KML file for FEMA's Disaster Recovery Centers (DRC). A DRC is a readily accessible facility or mobile office set up by FEMA where applicants may go for...

  12. Aim to International Shipping Center

    Institute of Scientific and Technical Information of China (English)

    Hu Wenxiu

    2009-01-01

    @@ Since 1990s,various countries in the world have been focusing on the construction of the key ports,leading to a fiercer competition between ports.For example,in East Asia,South Korea and Japan are rivaling for the international shipping center in Northeast Asia.Taking Busan Port and Gwangyang Port as the central ports,South Korea is boosting the ports expansion plans,to construct a"logistic center in Northeast Asia".Meanwhile.Japan is projecting the optimizmg and integration of port resources,to regain the international shipping center in Asia.The central government of China made plans for constructing Shanghai Shipping Center as early in 1996.and after 13 years'construction,now Shanghai Port has the largest cargo throughput and the second largest container throughput in the world.

  13. Center for Creative Studies, Detroit

    Science.gov (United States)

    AIA Journal, 1976

    1976-01-01

    One of the ten buildings chosen to receive 1976 AIA honor awards, the arts center houses the departments of sculpture, painting, graphics, advertising art, photography, and industrial design. (Author/MLF)

  14. CMS Innovation Center Model Participants

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Innovation Center develops new payment and service delivery models in accordance with the requirements of section 1115A of the Social Security Act....

  15. Clean Energy Solutions Center Services

    Energy Technology Data Exchange (ETDEWEB)

    2016-03-01

    The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  16. Center for Beam Physics, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The Center for Beam Physics is a multi-disciplinary research and development unit in the Accelerator and Fusion Research Division at Lawrence Berkeley Laboratory. At the heart of the Center`s mission is the fundamental quest for mechanisms of acceleration, radiation and focusing of energy. Dedicated to exploring the frontiers of the physics of (and with) particle and photon beams, its primary mission is to promote the science and technology of the production, manipulation, storage and control systems of charged particles and photons. The Center serves this mission via conceptual studies, theoretical and experimental research, design and development, institutional project involvement, external collaborations, association with industry and technology transfer. This roster provides a glimpse at the scientists, engineers, technical support, students, and administrative staff that make up this team and a flavor of their multifaceted activities during 1993.

  17. Records Center Program Billing System

    Data.gov (United States)

    National Archives and Records Administration — RCPBS supports the Records center programs (RCP) in producing invoices for the storage (NARS-5) and servicing of National Archives and Records Administration’s...

  18. CENTER FOR CYBER SECURITY STUDIES

    Data.gov (United States)

    Federal Laboratory Consortium — The mission of the Center for Cyber Security Studies is to enhance the education of midshipmen in all areas of cyber warfare, to facilitate the sharing of expertise...

  19. Relativistic two-center continuum

    OpenAIRE

    Wietschorke, Karl-Heinz; Schlüter, Paul; Soff, Gerhard; Rumrich, Klaus; Greiner, Walter

    2006-01-01

    A method is presented to define unique continuum states for the two-center Dirac Hamiltonian. In the spherical limit these states become the familiar angular-momentum eigenstates of the radial Coulomb potential. The different states for a fixed total energy ‖E‖>m may be distinguished by considering the asymptotic spin-angular distribution of states with unique scattering phases. The first numerical solutions of the two-center Dirac equation for continuum states are presented.

  20. User-Centered Data Management

    CERN Document Server

    Catarci, Tiziana; Kimani, Stephen

    2010-01-01

    This lecture covers several core issues in user-centered data management, including how to design usable interfaces that suitably support database tasks, and relevant approaches to visual querying, information visualization, and visual data mining. Novel interaction paradigms, e.g., mobile and interfaces that go beyond the visual dimension, are also discussed. Table of Contents: Why User-Centered / The Early Days: Visual Query Systems / Beyond Querying / More Advanced Applications / Non-Visual Interfaces / Conclusions

  1. Centered Sublattice and its Application

    Institute of Scientific and Technical Information of China (English)

    宋振明; 徐扬; 等

    1993-01-01

    In this paper,the concept of the centered sublattice is introduceed for lattice theory and the dis-composition theorem of a lattice is given.Based on the centered sublattice,we give some new descriptions of a modular lattice,a distributive lattice,a complemented lattice and an relatively complemented lattice,etc.These new decriptions established now researching methods for lattice theory.

  2. Italy INAF Analysis Center Report

    Science.gov (United States)

    Negusini, M.; Sarti, P.

    2013-01-01

    This report summarizes the activity of the Italian INAF VLBI Analysis Center. Our Analysis Center is located in Bologna, Italy and belongs to the Institute of Radioastronomy, which is part of the National Institute of Astrophysics. IRA runs the observatories of Medicina and Noto, where two 32-m VLBI AZ-EL telescopes are situated. This report contains the AC's VLBI data analysis activities and shortly outlines the investigations into the co-locations of space geodetic instruments.

  3. The Research Role of a National Center.

    Science.gov (United States)

    Silberman, Harry F.

    The functional role of a national center for vocational education depends on the people doing the work; consequently, the center sets its own agenda when it makes personal decisions. A center's role should include two elements: in setting its own research agenda, a center should take a broad perspective on vocational education; and a center should…

  4. Advanced Call Center Supporting WAP Access

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Traditional call centers can be accessed via speech only, and the call center based on web provides both data and speech access, but it needs a powerful terminal-computer. By analyzing traditional call centers and call centers based on web, this paper presents the framework of an advanced call center supporting WAP access. A typical service is also described in detail.

  5. A Shift from Teacher Centered to Learner Centered Approach

    Directory of Open Access Journals (Sweden)

    Jeanne Schreurs

    2014-06-01

    Full Text Available In the framework of the project Western Eastern Teachers' Education Network (WETEN funded by the Tempus program the network of university teachers were established to share expertise on effective teaching and learning in universities. This network for pedagogical innovation in higher education brought together the experts from EU to share good practice and new teaching methods with academic staff from two eastern countries, Moldova and Ukraine. The learner centered concept was analyzed and guidelines for creating learner centered courses were developed and piloted. The concepts and some experiences in course design were also implemented by trained teachers in the developed courses within the WETEN project.

  6. Finding Communities by Their Centers.

    Science.gov (United States)

    Chen, Yan; Zhao, Pei; Li, Ping; Zhang, Kai; Zhang, Jie

    2016-01-01

    Detecting communities or clusters in a real-world, networked system is of considerable interest in various fields such as sociology, biology, physics, engineering science, and interdisciplinary subjects, with significant efforts devoted in recent years. Many existing algorithms are only designed to identify the composition of communities, but not the structures. Whereas we believe that the local structures of communities can also shed important light on their detection. In this work, we develop a simple yet effective approach that simultaneously uncovers communities and their centers. The idea is based on the premise that organization of a community generally can be viewed as a high-density node surrounded by neighbors with lower densities, and community centers reside far apart from each other. We propose so-called "community centrality" to quantify likelihood of a node being the community centers in such a landscape, and then propagate multiple, significant center likelihood throughout the network via a diffusion process. Our approach is an efficient linear algorithm, and has demonstrated superior performance on a wide spectrum of synthetic and real world networks especially those with sparse connections amongst the community centers. PMID:27053090

  7. Finding Communities by Their Centers

    Science.gov (United States)

    Chen, Yan; Zhao, Pei; Li, Ping; Zhang, Kai; Zhang, Jie

    2016-04-01

    Detecting communities or clusters in a real-world, networked system is of considerable interest in various fields such as sociology, biology, physics, engineering science, and interdisciplinary subjects, with significant efforts devoted in recent years. Many existing algorithms are only designed to identify the composition of communities, but not the structures. Whereas we believe that the local structures of communities can also shed important light on their detection. In this work, we develop a simple yet effective approach that simultaneously uncovers communities and their centers. The idea is based on the premise that organization of a community generally can be viewed as a high-density node surrounded by neighbors with lower densities, and community centers reside far apart from each other. We propose so-called “community centrality” to quantify likelihood of a node being the community centers in such a landscape, and then propagate multiple, significant center likelihood throughout the network via a diffusion process. Our approach is an efficient linear algorithm, and has demonstrated superior performance on a wide spectrum of synthetic and real world networks especially those with sparse connections amongst the community centers.

  8. INIS National Center in Syria

    International Nuclear Information System (INIS)

    International Nuclear Information System (INIS) is the world's leading information system on the peaceful uses of nuclear science and technology and it is operated by the International Atomic Energy Agency (IAEA) in Vienna, Austria. An overview of INIS products, services, philosophy and operation is given. INIS hold a database containing over 2.5 million references increasing at approximately 85,000 references per year and a collection of full text non-conventional, or grey literature that would be hard to obtain elsewhere. In addition, the PC-based software for inputs preparation (WinFIBRE) is demonstrated. INIS national center in Syria is considered as a regional center for INIS inputs preparation. The center is responsible for selecting the relevant nuclear literature produced and published in Syria and preparing the national inputs and send them to INIS Secretariat to be included in the INIS database. The center also provides INIS services and products to users within Syria. Availability of INIS Database on CD-ROMs, which updated monthly, and the internet version, which updated weekly, and the NCL collections are also presented. Finally, translation activity of the center, such as INIS Booklet entitled Presenting INIS, and the INIS Thesaurus into Arabic were mentioned. This was an in-kind contribution from the Atomic Energy Commission of Syria to support the valuable work of the INIS and Nuclear Knowledge Management (NKM) section and will contribute significantly the dissemination of information among the researchers and scientists in the Arab Countries. (author)

  9. Center Innovation Fund: KSC CIF Program

    Data.gov (United States)

    National Aeronautics and Space Administration — Each individual NASA Center has full discretion on the use of the funds and the Center Chief Technologists coordinates a competitive process at their Center for the...

  10. How to Understand Transplant Center Statistics

    Science.gov (United States)

    ... Print this page How to understand transplant center statistics Because statistics can be hard to understand, we recommend you ... NMDP transplant centers How to understand transplant center statistics Because statistics can be hard to understand, we ...

  11. Influence of Fiber Undulations on Stiffness of Thin Filament-Wound Cylinders%纤维缠绕复合材料壳体起伏区域刚度的研究

    Institute of Scientific and Technical Information of China (English)

    郭章新; 韩小平; 朱西平; 支希哲

    2011-01-01

    Aim. The introduction of the full paper reviews a number of papers in the open literature and then proposes the above-mentioned title's research, which we believe is more efficient than previously and which is explained in sections 1 through 4. Fig. 2 in section 1 gives the micromechanical geometry in the fiber crossover regions of filament-wound cylinders. Section 2 shows how to calculate the stiffness matrices A (stretching), B (stretching-bending coupling) and D( bending) along the length of the undulation as a function of winding angle. Section 3 gives the method for calculating the stiffness of filament winding composites. The calculated results, presented in Figs. 3 through 5 in section 4, and their discussion provide useful information for efficiently establishing the FEA (finite element analysis) of composite pressure vessels.%文章针对起伏区域纤维束的非正交交织的特点,提出一种计算缠绕复合材料的起伏区域内各点刚度的方法.通过算例,计算了整个起伏区域内不同点在不同缠绕角时的各项刚度系数值,给出了各项刚度系数随起伏区域的位置改变以及随着缠绕角变化的三维曲线,分析讨论了各项刚度系数在整个起伏区域内的变化规律,为纤维缠绕复合材料气瓶等高压密封容器的提前泄露问题的有限元分析提供了理论依据.

  12. 78 FR 14549 - National Contact Center; Information Collection; National Contact Center Customer Evaluation Survey

    Science.gov (United States)

    2013-03-06

    ... ADMINISTRATION National Contact Center; Information Collection; National Contact Center Customer Evaluation... requirement regarding the National Contact Center customer evaluation surveys. In this request, the previously... compare its customer service levels to those of private industry contact centers. DATES: Submit...

  13. Center for Beam Physics, 1993

    International Nuclear Information System (INIS)

    The Center for Beam Physics is a multi-disciplinary research and development unit in the Accelerator and Fusion Research Division at Lawrence Berkeley Laboratory. At the heart of the Center's mission is the fundamental quest for mechanisms of acceleration, radiation and focusing of energy. Dedicated to exploring the frontiers of the physics of (and with) particle and photon beams, its primary mission is to promote the science and technology of the production, manipulation, storage and control systems of charged particles and photons. The Center serves this mission via conceptual studies, theoretical and experimental research, design and development, institutional project involvement, external collaborations, association with industry and technology transfer. This roster provides a glimpse at the scientists, engineers, technical support, students, and administrative staff that make up this team and a flavor of their multifaceted activities during 1993

  14. Self-Access Centers: Maximizing Learners’ Access to Center Resources

    Directory of Open Access Journals (Sweden)

    Mark W. Tanner

    2010-09-01

    Full Text Available Originally published in TESL-EJ March 2009, Volume 12, Number 4 (http://tesl-ej.org/ej48/a2.html. Reprinted with permission from the authors.Although some students have discovered how to use self-access centers effectively, the majority appear to be unaware of available resources. A website and database of materials were created to help students locate materials and use the Self-Access Study Center (SASC at Brigham Young University’s English Language Center (ELC more effectively. Students took two surveys regarding their use of the SASC. The first survey was given before the website and database were made available. A second survey was administered 12 weeks after students had been introduced to the resource. An analysis of the data shows that students tend to use SASC resources more autonomously as a result of having a web-based database. The survey results suggest that SAC managers can encourage more autonomous use of center materials by provided a website and database to help students find appropriate materials to use to learn English.

  15. NASA(Field Center Based) Technology Commercialization Centers

    Science.gov (United States)

    1995-01-01

    Under the direction of the IC(sup 2) Institute, the Johnson Technology Commercialization Center has met or exceeded all planned milestones and metrics during the first two and a half years of the NTCC program. The Center has established itself as an agent for technology transfer and economic development in- the Clear Lake community, and is positioned to continue as a stand-alone operation. This report presents data on the experimental JTCC program, including all objective measures tracked over its duration. While the metrics are all positive, the data indicates a shortage of NASA technologies with strong commercial potential, barriers to the identification and transfer of technologies which may have potential, and small financial return to NASA via royalty-bearing licenses. The Center has not yet reached the goal of self-sufficiency based on rental income, and remains dependent on NASA funding. The most important issues raised by the report are the need for broader and deeper community participation in the Center, technology sourcing beyond JSC, and the form of future funding which will be appropriate.

  16. Center Innovation Fund: JPL CIF Program

    Data.gov (United States)

    National Aeronautics and Space Administration — Funds are distributed to each NASA Center to support emerging technologies and creative initiatives that leverage Center talent and capabilities. NASA scientists...

  17. PACS strategy for imaging centers.

    Science.gov (United States)

    Bedel, Victoria; Zdanowicz, Mark

    2004-01-01

    Picture archiving and communications systems (PACS) have been available in imaging centers for many years, but they often were less functional, were not well integrated into patient information systems, and lacked the network backbone to implement a system. As modalities are replaced and technology improves, the ability and time for an imaging center to acquire, integrate, and utilize PACS has arrived. However, each imaging center must determine why it should invest in PACS. A business plan is the fundamental need. Each imaging center must understand its target market, growth rate, and staffing plans. Additional considerations lie in current and future modality availability, the need for offsite delivery of images and reports, and the potential need for remote transmission of images. These issues must be identified and prioritized. A multidisciplinary team is essential. The most successful PACS implementation begins with complete involvement from all levels. The team should be comprised of people with complementary skills who are committed to a common purpose, set of performance goals, and approach for which they hold themselves mutually accountable. The team must jointly decide on the project's objectives. These objectives fall under 4 categories: clinical, service, financial, and performance. PACS must be considered a tool to help accomplish each objective. The imaging center must determine its top priorities, then translate them into a technology "wish list." The center can then list those pieces of technology that are most important and prioritize them. There are even more considerations for connecting multiple imaging centers. The team must create a comprehensive request for proposal (RFP) and determine the vendors that will receive the document. Once the RFP responses have been received and the vendor has been selected, an effective training plan must be executed. Training plans should be competency-based, ensuring comfort and competency among all staff. Upon

  18. User-centered agile method

    CERN Document Server

    Deuff, Dominique

    2013-01-01

    Agile development methods began to emerge around 20 years ago. However, it was not until the early 2000s that they began to be widely used in industry. This growth was often due to the advent of Internet services requiring faster cycles of development in order to heighten the rate at which an ever-greater number of functionalities were made available. In parallel, user-centered design (UCD) methods were also becoming more and more widely used: hence, user-centered design and agile methods were bound to cross paths, at least in the telecoms industry! During this period, in the field of telec

  19. Directions in Center Director Training

    Science.gov (United States)

    Bloom, Paula Jorde; Vinci, Yasmina; Rafanello, Donna; Donohue, Chip

    2011-01-01

    Exchange invited some of the leading trend watchers in the arena of director training to share their insights on the current state and future directions in this country. This article presents the authors' insights on the directions in center director training. They also share their views on whether the amount of and quality of training out there…

  20. Financial Management in Imaging Center

    Directory of Open Access Journals (Sweden)

    Arash Deljou

    2009-01-01

    Full Text Available "nIn this article, we provide a brief overview of the three main financial statements: income statement, balance sheet, and statement of cash flows, and we discuss the major landmarks in each. We discuss financial ratios and other measures of performance that radiologists and CFOs of radiology department can use to detect problems and isolate their root cause. "nInterest rates are a factor in a number of decisions (more specifically in an inflated economy, including the required rate of return on a new diagnostic imaging center, expansion, refinancing, lease versus buy decisions, and others. We discuss the factors that cause interest rates to rise or fall and what can be done about them. "nWhen considering the development of a new diagnostic imaging center, one of the key factors that a financing source, manufacturer-based, independent bank, or other third party, considers is how much cash equity the owners are putting into the project. They want to know this answer for a variety of reasons and will analyze the answer in a few different ways. "nDiagnostic imaging center equity is usually defined as the amount of cash required to get the center up and running, and until it begins to cash flow positively on its own. The art of determining equity comes from a couple of factors and from the early stages of the development of a project.  

  1. Kepler Science Operations Center Architecture

    Science.gov (United States)

    Middour, Christopher; Klaus, Todd; Jenkins, Jon; Pletcher, David; Cote, Miles; Chandrasekaran, Hema; Wohler, Bill; Girouard, Forrest; Gunter, Jay P.; Uddin, Kamal; Allen, Christopher; Hall, Jennifer; Ibrahim, Khadeejah; Clarke, Bruce; Li, Jie; McCauliff, Sean; Quintana, Elisa; Sommers, Jeneen; Stroozas, Brett; Tenenbaum, Peter; Twicken, Joseph; Wu, Hayley; Caldwell, Doug; Bryson, Stephen; Bhavsar,Paresh

    2010-01-01

    We give an overview of the operational concepts and architecture of the Kepler Science Data Pipeline. Designed, developed, operated, and maintained by the Science Operations Center (SOC) at NASA Ames Research Center, the Kepler Science Data Pipeline is central element of the Kepler Ground Data System. The SOC charter is to analyze stellar photometric data from the Kepler spacecraft and report results to the Kepler Science Office for further analysis. We describe how this is accomplished via the Kepler Science Data Pipeline, including the hardware infrastructure, scientific algorithms, and operational procedures. The SOC consists of an office at Ames Research Center, software development and operations departments, and a data center that hosts the computers required to perform data analysis. We discuss the high-performance, parallel computing software modules of the Kepler Science Data Pipeline that perform transit photometry, pixel-level calibration, systematic error-correction, attitude determination, stellar target management, and instrument characterization. We explain how data processing environments are divided to support operational processing and test needs. We explain the operational timelines for data processing and the data constructs that flow into the Kepler Science Data Pipeline.

  2. VMware vCenter cookbook

    CERN Document Server

    Kuminsky, Konstantin

    2015-01-01

    If you are a system administrator who has some experience with virtualization and already uses VMware vCenter, but wishes to learn more, then this is the book for you. If you are looking for tips or shortcuts for common administration tasks as well as workarounds for pain points in vSphere administration, you'll find this guide useful.

  3. Kempinski Hotel Beijing Lufthansa Center

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A shining star on the eastern part of Beijing Kempinski Hotel Beijing Lufthansa Center is located at the heart of the city, a fully integrated business complex with serviced apartments, top-class offices and showrooms. The hotel offers unrivaled conference, business and leisure facilities ideal for business travelers and leisure guests alike. Its impressive blend of grand Chinese cul-

  4. An International Development Technology Center

    Science.gov (United States)

    Morgan, Robert P.

    1969-01-01

    Main focus of the Center is "the application of science and technology to the solution of problems faced by people in less-developed areas of the world. Adapted from paper presented at ASEE Annual Meeting, The Pennsylvania State University, June, 1969. (Author/WM)

  5. School-Based Health Centers

    Science.gov (United States)

    ... in school increase high school graduation rates decrease school discipline cases Studies show that teens, who might resist going to a doctor, are more willing to get help for problems like depression and weight issues at a school-based health center. This might be because they ...

  6. Advanced Call Center Supporting WAP Access

    Institute of Scientific and Technical Information of China (English)

    YUANXiao-hua; CHENJun-liang

    2001-01-01

    Traditional call centers can be accessed via speech only, and the call center based on web provides both da-ta and speech access,but it needs a powerful terminal-computer.By analyzing traditional call centers and call cen-ters based on web, this paper presents the framework of an advanced call center supporting WAP access.A typical service is also described in detail.

  7. Fuzzy Logic Reliability Centered Maintenance

    Directory of Open Access Journals (Sweden)

    Felecia .

    2014-01-01

    Full Text Available Reliability Centered Maintenence (RCM is a systematic maintenence strategy based on system reliability. Application of RCM process will not always come out with a binary output of “yes” and “no”. Most of the time they are not supported with available detail information to calculate system reliability. The fuzzy logic method attempts to eliminate the uncertainty by providing “truth” in different degrees.Data and responses from maintenance department will be processed using the two methods (reliability centered maintenance and fuzzy logic to design maintenance strategy for the company. The results of the fuzzy logic RCM application are maintenance strategy which fit with current and future condition.

  8. Rolex learning center English guide

    CERN Document Server

    Della Casa, Francesco

    2012-01-01

    The novel architectural form of this building, conceived of by the architects of SAANA (winners of the Pritzker Prize in 2010), compelled the building engineers to come up with unprecedented structural, technical and logistical solutions. And yet, once the Rolex Learning Center was complete, the ingenuity required for its construction had become practically invisible in the eyes of the uninitiated. This richly illustrated guide provides, in condensed form, an account of the extraordinary adventure of the realization of the Rolex Learning Center. It explains in detail the context of its construction and brings to light the spatial subtleties of its architecture. In addition, it provides the visitor of the building with all the needed technical information and many novel facts and figures.

  9. Jellyfish: Networking Data Centers Randomly

    CERN Document Server

    Singla, Ankit; Popa, Lucian; Godfrey, P Brighten

    2011-01-01

    Industry experience indicates that the ability to incrementally expand data centers is essential. However, existing high-bandwidth network designs have rigid structure that interferes with incremental expansion. We present Jellyfish, a high-capacity network interconnect, which, by adopting a random graph topology, yields itself naturally to incremental expansion. Somewhat surprisingly, Jellyfish is more cost-efficient than a fat-tree: A Jellyfish interconnect built using the same equipment as a fat-tree, supports as many as 25% more servers at full capacity at the scale of a few thousand nodes, and this advantage improves with scale. Jellyfish also allows great flexibility in building networks with different degrees of oversubscription. However, Jellyfish's unstructured design brings new challenges in routing, physical layout, and wiring. We describe and evaluate approaches that resolve these challenges effectively, indicating that Jellyfish could be deployed in today's data centers.

  10. The Fermilab Particle Astrophysics Center

    Energy Technology Data Exchange (ETDEWEB)

    2004-11-01

    The Particle Astrophysics Center was established in fall of 2004. Fermilab director Michael S. Witherell has named Fermilab cosmologist Edward ''Rocky'' Kolb as its first director. The Center will function as an intellectual focus for particle astrophysics at Fermilab, bringing together the Theoretical and Experimental Astrophysics Groups. It also encompasses existing astrophysics projects, including the Sloan Digital Sky Survey, the Cryogenic Dark Matter Search, and the Pierre Auger Cosmic Ray Observatory, as well as proposed projects, including the SuperNova Acceleration Probe to study dark energy as part of the Joint Dark Energy Mission, and the ground-based Dark Energy Survey aimed at measuring the dark energy equation of state.

  11. Land Center for Human Rights

    OpenAIRE

    Saber, Karam

    2013-01-01

    Why Land Center for Human Rights? The farmers’ issue represents a new and very important dimension for the Human Rights movement in Egypt for several reasons. The inadequacy of a legislative structure to protect agrarian laborers. In consequence, they are exposed to daily violations. The main targeted categories are women, children and permanent or seasonal agrarian laborers. The widening gap between urban and rural Egypt, especially in the services. Thus, a wide category of people are expose...

  12. Drinfeld center of planar algebra

    CERN Document Server

    Das, Paramita; Gupta, Ved Prakash

    2012-01-01

    We introduce fusion and contragadient of affine representations of a planar algebra $P$ (not necessarily having finite depth). We prove that if $N \\subset M$ is a subfactor realization of $P$, then the Drinfeld center of the $N$-$N$-bimodule category generated by $_N L^2 (M)_M$, is equivalent to the category Hilbert affine representations of $P$ satisfying certain finiteness criterion. As a consequence, we prove Kevin Walker's conjecture for planar algebras.

  13. Human Centered Design for Development

    OpenAIRE

    Knoche, Hendrik; Rao, Sheshagiri, P. R.; Huang, Jeffrey

    2011-01-01

    This paper describes the challenges faced in ICTD by reviewing the lessons learned from a project geared at improving the livelihood of marginal farmers in India through wireless sensor networks. Insufficient user participation, lack of attention to user needs, and a primary focus on technology in the design process led to unconvinced target users who were not interested in the new technology. The authors discuss benefits that ICTD can reap from incorporating human-centered design (HCD) princ...

  14. Expeditionary mobile operations center (EMOC)

    OpenAIRE

    Gonzalez, Jose

    2014-01-01

    This research explores a viable solution to the U.S.Marine Corps’ (USMC) communications gap at the tactical edge. The aim is to leverage commercial-off-the-shelf (COTS) technology to provide a combat operations center (COC) like communication architecture to small units operating in austere environments. The proposed architecture required must be lightweight, energy efficient, and allow greater mobility through a reduced footprint and energy consumption. By reducing the energy required for un...

  15. The Scientific Data Management Center

    OpenAIRE

    Shoshani, Arie

    2006-01-01

    With the increasing volume and complexity of data produced by ultra-scale simulations and high-throughput experiments, understanding the science is largely hampered by the lack of comprehensive, end-to-end data management solutions ranging from initial data acquisition to final analysis and visualization. The Scientific Data Management (SDM) Center is bringing a set of advanced data management technologies to DOE scientists in various application domains including astrophysics, climate, ...

  16. Clean Energy Solutions Center (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Reategui, S.

    2012-07-01

    The Clean Energy Ministerial launched the Clean Energy Solutions Center in April, 2011 for major economy countries, led by Australia and U.S. with other CEM partners. Partnership with UN-Energy is extending scope to support all developing countries: 1. Enhance resources on policies relating to energy access, small to medium enterprises (SMEs), and financing programs; 2. Offer expert policy assistance to all countries; 3. Expand peer to peer learning, training, and deployment and policy data for developing countries.

  17. The Fort Collins Science Center

    Science.gov (United States)

    Wilson, Juliette T.; Banowetz, Michele M.

    2012-01-01

    With a focus on biological research, the U.S. Geological Survey Fort Collins Science Center (FORT) develops and disseminates science-based information and tools to support natural resource decision-making. This brochure succinctly describes the integrated science capabilities, products, and services that the FORT science community offers across the disciplines of aquatic systems, ecosystem dynamics, information science, invasive species science, policy analysis and social science assistance, and trust species and habitats.

  18. Learning System Center App Controller

    CERN Document Server

    Naeem, Nasir

    2015-01-01

    This book is intended for IT professionals working with Hyper-V, Azure cloud, VMM, and private cloud technologies who are looking for a quick way to get up and running with System Center 2012 R2 App Controller. To get the most out of this book, you should be familiar with Microsoft Hyper-V technology. Knowledge of Virtual Machine Manager is helpful but not mandatory.

  19. Hydrogen Bonds Involving Metal Centers

    OpenAIRE

    Pavlović, G.; Raos, N.

    2006-01-01

    Hydrogen bonds involving metal center as a hydrogen donor or hydrogen acceptor are only a specific type of metal-hydrogen interactions; it is therefore not easy to differentiate hydrogen bond from other metal-hydrogen interactions, especially agostic ones. The first part of the review is therefore devoted to the results of structural chemistry and molecular spectroscopy (NMR, IR), as a tool for differentiating hydrogen bondings from other hydrogen interactions. The classical examples of Pt···...

  20. Fuzzy Logic Reliability Centered Maintenance

    OpenAIRE

    , Felecia

    2014-01-01

    Reliability Centered Maintenence (RCM) is a systematic maintenence strategy based on system reliability. Application of RCM process will not always come out with a binary output of “yes” and “no”. Most of the time they are not supported with available detail information to calculate system reliability. The fuzzy logic method attempts to eliminate the uncertainty by providing “truth” in different degrees.Data and responses from maintenance department will be processed using the two methods (re...