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


    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. 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)


    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.

  3. 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)


    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.

  4. LCLS Undulator Design Development

    CERN Document Server

    Vasserman, Isaac; Den Hartog, P; Moog, Elizabeth; Sasaki, Shigemi; Trakhtenberg, Emil; White, Marion


    The fractional variation in deflection parameter K between segments of the 130.4-m-long undulator line for the Linac Coherent Light Source (LCLS) must be < 1.5 x 10-4. Mechanical shims were used to set the undulator gap to control K in the prototype, but this is too tedious a procedure to be used for all 33 undulator segments. Although the prototype undulator met all of the LCLS specifications, development continued in order to simplify the system. Various other alternatives for adjusting the field were considered. A canted-pole geometry was adopted that allows the K value to be changed by lateral translation of the entire undulator segment. This scheme also facilitates tapering the undulator line to accommodate energy loss in the electron beam. The prototype undulator was subsequently modified to test the canted-pole concept. Magnetic measurements demonstrated that the undulator with canted poles meets all LCLS specifications, and is more cost-effective to implement.

  5. The JLAB UV Undulator

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  6. Tapered undulators for SASE FELs

    CERN Document Server

    Fawley, W M; Vinokurov, N A


    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.

  7. 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)


    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.)

  8. 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...

  9. Undulator radiation in a waveguide

    Energy Technology Data Exchange (ETDEWEB)

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


    We propose an analytical approach to characterize undulator radiation near resonance, when the presence of the vacuum-pipe considerably affects radiation properties. This is the case of the far-infrared undulator beamline at the Free-electron LASer (FEL) in Hamburg (FLASH), that will be capable of delivering pulses in the TeraHertz (THz) range. This undulator will allow pump-probe experiments where THz pulses are naturally synchronized to the VUV pulse from the FEL, as well as the development of novel electron-beam diagnostics techniques. Since the THz radiation diffraction-size exceeds the vacuum-chamber dimensions, characterization of infrared radiation must be performed accounting for the presence of a waveguide.We developed a theory of undulator radiation in a waveguide based on paraxial and resonance approximation. We solved the field equation with a tensor Green's function technique, and extracted figure of merits describing in a simple way the influence of the vacuum-pipe on the radiation pulse as a function of the problem parameters. Our theory, that makes consistent use of dimensionless analysis, allows treatment and physical understanding of many asymptotes of the parameter space, together with their region of applicability. (orig.)

  10. Transition undulator radiation as bright infrared sources

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  11. Observational constraints on undulant cosmologies

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  12. Coherent radiation in an undulator (United States)

    Chin, Yong Ho


    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.

  13. Damping Undulators vs Damping Wigglers

    CERN Document Server

    Muchnoi, Nickolai


    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.

  14. Undulation Instability of Epithelial Tissues

    CERN Document Server

    Basan, Markus; Prost, Jacques; Risler, Thomas; 10.1103/PhysRevLett.106.158101


    Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion.

  15. LCLS Undulator Quadrupole Fiducialization Plan

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Zachary; Levashov, Michael; Lundahl, Eric; Reese, Ed; LeCocq, Catherine; Ruland, Robert; /SLAC


    This note presents the fiducialization plan for the LCLS undulator quadrupoles. The note begins by summarizing the requirements for the fiducialization. A discussion of the measurement equipment is presented, followed by the methods used to perform the fiducialization and check the results. This is followed by the detailed fiducialization plan in which each step is enumerated. Finally, the measurement results and data storage formats are presented. The LCLS is made up of 33 assemblies consisting of an undulator, quadrupole, beam finder wire, and other components mounted on a girder. The components must be mounted in such a way that the beam passes down the axis of each component. In this note, we describe how the ideal beam axis is related to tooling balls on the quadrupole. This step, called fiducialization, is necessary because the ideal beam axis is determined magnetically, whereas tangible objects must be used to locate the quadrupole. The note begins with the list of fiducialization requirements. The laboratory in which the work will be performed and the relevant equipment is then briefly described. This is followed by a discussion of the methods used to perform the fiducialization and the methods used to check the results. A detailed fiducialization plan is presented in which all the steps of fiducialization are enumerated. A discussion of the resulting data files and directory structure concludes the note.

  16. Radiation emitted by transverse-gradient undulators (United States)

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


    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.

  17. 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


    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.

  18. Undulator with dynamic compensation of magnetic forces

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  19. Wakefield Undulator For Generating X-rays

    CERN Document Server

    Opanasenko, A N


    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.

  20. Positioning system for the LCLS undulator.

    Energy Technology Data Exchange (ETDEWEB)

    Trakhenberg, E. M.


    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.

  1. Interferometry using undulator sources (invited, abstract) (United States)

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


    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.

  2. Optical Fibre Dosimeter for SASE FEL Undulators

    CERN Document Server

    Körfer, M


    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 ...

  3. Undulators at HiSOR - a compact racetrack-type ring. (United States)

    Hiraya, A; Yoshida, K; Yagi, S; Taniguchi, M; Kimura, S I; Hama, H; Takayama, T; Amano, D


    A compact racetrack-type 700 MeV storage ring (HiSOR) has been constructed at Hiroshima Synchrotron Radiation Center (HSRC). As the ring was planned for synchrotron radiation research on science and technology using VUV to X-rays up to 5 keV with limited size and cost, the ring was designed (i) to realize a high magnetic field (2.7 T) using conventional dipole magnets for higher critical energy, and (ii) to include two straight sections for insertion devices. A linear undulator (25-300 eV) and a new-type helical/linear undulator were installed at the two straight sections. The latter undulator consists of upper and lower jaws, as in a planar undulator; each jaw consists of one fixed magnet array at the centre and two magnet arrays on both sides. By longitudinal displacement of the side magnet arrays, the phase between the vertical and horizontal magnetic fields, and therefore the polarization (right- or left-circular, elliptical, linear) can be selected. The helical/linear undulator gives almost perfect circular polarization at 4-40 eV in the helical configuration without changing the phase of the magnet arrays, as well as linearly polarized light at 3-300 eV in the linear configuration.

  4. Coherent Radiation Effects in the LCLS Undulator

    CERN Document Server

    Reiche, Sven


    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...

  5. 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


    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.

  6. High-temperature superconducting undulator magnets (United States)

    Kesgin, Ibrahim; Kasa, Matthew; Ivanyushenkov, Yury; Welp, Ulrich


    This paper presents test results on a prototype superconducting undulator magnet fabricated using 15% Zr-doped rare-earth barium copper oxide high temperature superconducting (HTS) tapes. On an 11-pole magnet we demonstrate an engineering current density, J e, of more than 2.1 kA mm‑2 at 4.2 K, a value that is 40% higher than reached in comparable devices wound with NbTi-wire, which is used in all currently operating superconducting undulators. A novel winding scheme enabling the continuous winding of tape-shaped conductors into the intricate undulator magnets as well as a partial interlayer insulation procedure were essential in reaching this advance in performance. Currently, there are rapid advances in the performance of HTS; therefore, achieving even higher current densities in an undulator structure or/and operating it at temperatures higher than 4.2 K will be possible, which would substantially simplify the cryogenic design and reduce overall costs.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  8. Generation of radiation by intense plasma and electromagnetic undulators

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, C.


    We examine the characteristics of the classical radiation emission resulting from the interaction of a relativistic electron beam that propagates perpendicularly through a large amplitude relativistic plasma wave. Such a study is useful for evaluating the feasibility of using relativistic plasma waves as extremely short wavelength undulators for generating short wavelength radiation. The electron trajectories in a plasma wave undulator and in an ac FEL undulator are obtained using perturbation techniques. The spontaneous radiation frequency spectrum and angular distribution emitted by a single electron oscillating in these two undulators are then calculated. The radiation gain of a copropagating electromagnetic wave is calculated. The approximate analytic results for the trajectories, spontaneous radiation and gain are compared with 3-D simulation results. The characteristics of the plasma wave undulator are compared with the ac FEL undulator and linearly polarized magnetic undulator. 50 refs., 26 figs., 3 tabs.

  9. An experimental superconducting helical undulator

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  10. Undulators and free-electron lasers

    CERN Document Server

    Luchini, P


    This book is a reference text for all those working in free-electron laser research as well as being a learning aid for physicists and graduate students who wish an introduction to this field. Only a basic understanding of relativistic mechanics and electromagnetism is presupposed. After an overview of early developments and general principles of operation, the different models that can be used to describe free-electron lasers are presented, organized according to their range of applicability. The relevent conceptual and mathematical constructs are built up from first principles with attention to obtaining the practically important results in a simple but rigorous way. Interaction of the undulator with the driving electron accelerator and the laser cavity and design of undulator magnets are treated and an overview is given of some typical experiments.

  11. Thermal analysis of superconducting undulator cryomodules (United States)

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


    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.

  12. Exact relativistic theory of geoid's undulation

    CERN Document Server

    Kopeikin, Sergei; Karpik, Alexander


    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...

  13. In vacuum undulator task force report

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

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

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen


    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 the fully non-linear regime down-drift spits and migrating shoreline undulations are described.Three different shoreline shapes are found depending on the wave conditions: undulations with no spits, undulations with shore parallel spit and undulations with reconnecting spits. © 2012 Published by Elsevier B.V....

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

    Institute of Scientific and Technical Information of China (English)


    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.

  16. Tunable polarization plasma channel undulator for narrow bandwidth photon emission (United States)

    Rykovanov, S. G.; Wang, J. W.; Kharin, V. Yu.; Lei, B.; Schroeder, C. B.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.


    The theory of a plasma undulator excited by a short intense laser pulse in a parabolic plasma channel is presented. The undulator fields are generated either by the laser pulse incident off-axis and/or under the angle with respect to the channel axis. Linear plasma theory is used to derive the wakefield structure. It is shown that the electrons injected into the plasma wakefields experience betatron motion and undulator oscillations. Optimal electron beam injection conditions are derived for minimizing the amplitude of the betatron motion, producing narrow-bandwidth undulator radiation. Polarization control is readily achieved by varying the laser pulse injection conditions.

  17. LCLS Undulator Commissioning, Alignment, and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, Heinz-Dieter


    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).

  18. Design and analysis of a Be window for the APS diagnostics undulator beamline

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, I.C.; Yang, B.X.; Sharma, S. [Argonne National Lab., IL (United States). Advanced Photon Source


    The design of a beryllium (Be) window for use under the extremely high heat load of an undulator beam is one of the challenges for third-generation synchrotron radiation beamlines. A novel design of a Be window is presented for the Advanced Photon Source (APS) diagnostics undulator beamline, whose beam has a peak power density of 150 W/mm{sup 2} (7 GeV/100 mA stored beam). The window has a double concave profile with a thickness of 0.5 mm at the center and is brazed to a water-cooled oxygen-free, high-conductivity (OFHC) copper manifold. Finite-element thermal analysis of the Be window is also presented.

  19. Position Stability Monitoring of THEthe LCLS Undulator Quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  20. Effects of Tapered Betafunction in the LCLS Undulators

    CERN Document Server

    Goldammer, K; Huang, Z


    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.

  1. Undulators to FELs: Nanometers, Femtoseconds, Coherence and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Attwood, David [University of California Berkeley


    For scientists in many fields, from material science to the life sciences and archeology, synchrotron radiation, and in particular undulator radiation, has provide an intense source of x-rays which are tunable to the absorption edges of particular elements of interest, often permitting studies at high spatial and spectral resolution. Now a close cousin to the undulator, the x-ray free electron laser (XFEL) has emerged with improved spatial coherence and, perhaps more importantly, femtosecond pulse durations which permit dynamical studies. In the future attosecond x-ray capabilities are anticipated. In this colloqium we will describe some state of the art undulator studies, how undulators work, the evolution to FELs, their pulse and coherence properties, and the types of experiments envisioned.

  2. The Effects of Undulator Field on Stored Electron Beam


    Thananchai DASRI; Supagorn RUGMAI


    In order to extend the usable photon spectrum to higher photon flux, an undulator with periodic magnetic field has to be installed into the storage ring of the synchrotron facility. This paper presents the perturbations from the magnetic field of such a device on the electron beam dynamics in the ring. Theories and an example of a practical device are discussed. The U60 undulator of the Siam Photon Source is selected for illustrating these ideas.Graphical abstract

  3. The Effects of Undulator Field on Stored Electron Beam

    Directory of Open Access Journals (Sweden)

    Thananchai DASRI


    Full Text Available In order to extend the usable photon spectrum to higher photon flux, an undulator with periodic magnetic field has to be installed into the storage ring of the synchrotron facility. This paper presents the perturbations from the magnetic field of such a device on the electron beam dynamics in the ring. Theories and an example of a practical device are discussed. The U60 undulator of the Siam Photon Source is selected for illustrating these ideas.Graphical abstract

  4. U60 Undulator: An Insertion Device for the Siam Photon Source


    Thananchai DASRI


    Properties of insertion device, undulators, for the synchrotron light source are reviewed. Undulators are magnetic devices installed in the storage ring to improve the properties of the synchrotron light. First, the ideal simulated undulator fields will be discussed. Later the simulated fields produced by a defective undulator will be shown. Last, their effects on the stored electron beam are presented. The U60 undulator of the Siam Photon Source is used as an example.

  5. U60 Undulator: An Insertion Device for the Siam Photon Source

    Directory of Open Access Journals (Sweden)

    Thananchai DASRI


    Full Text Available Properties of insertion device, undulators, for the synchrotron light source are reviewed. Undulators are magnetic devices installed in the storage ring to improve the properties of the synchrotron light. First, the ideal simulated undulator fields will be discussed. Later the simulated fields produced by a defective undulator will be shown. Last, their effects on the stored electron beam are presented. The U60 undulator of the Siam Photon Source is used as an example.

  6. 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)


    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.

  7. Plasma undulator excited by high-order mode lasers (United States)

    Wang, Jingwei; Rykovanov, Sergey


    A laser-created plasma undulator together with a laser-plasma accelerator makes it possible to construct an economical and extremely compact XFEL. However, the spectrum spread of the radiation from the current plasma undulators is too large for XFELs, because of the different values of strength parameters. The phase slippage between the electrons and the wakefield also limits the number of the electron oscillation cycles, thus reduces the performance of XFEL. Here we proposed a phase-locked plasma undulator created by high-order mode lasers. The modulating field is uniform along the transverse direction by choosing appropriate laser intensities of the modes, which enables all the electrons oscillate with the same strength parameter. The plasma density is tapered to lock the phase between the electrons and the wakefield, which signally increases the oscillation cycles. As a result, X-ray radiation with high brightness and narrow bandwidth is generated by injecting a high-energy electron beam into the novel plasma undulator. The beam loading limit indicates that the current of the electron beam could be hundreds of Ampere. These properties imply that such a plasma undulator may have great potential in compact XFELs. This work was supported by the Helmholtz Association (Young Investigator's Group No. VH-NG-1037).

  8. 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


    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 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.

  9. 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


    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.

  10. Commissioning of the Delta Polarizing Undulator at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Nuhn, Heinz-Dieter


    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).

  11. A wire scanning type position monitor for an undulator radiation (United States)

    Zhang, Xiaowei; Sugiyama, Hiroshi; Ando, Masami; Xia, Shaojian; Shiwaku, Hideaki


    A scanning wire position monitor for insertion devices was designed and installed in an x-ray undulator beam line. It consists of a graphite wire, a copper mesh for electric shielding, and a motor-driven linear guide. The wire of the monitor was tested under the undulator radiation thermal load. It has been found that the signal level of the monitor was proportional to the radiation power density on the wire. Even when the wire crossed the beam during the x-ray experiment, no detectable influence on the experiment was observed.

  12. The importance of axonal undulation in diffusion MR measurements: a Monte Carlo simulation study. (United States)

    Nilsson, Markus; Lätt, Jimmy; Ståhlberg, Freddy; van Westen, Danielle; Hagslätt, Håkan


    Many axons follow wave-like undulating courses. This is a general feature of extracranial nerve segments, but is also found in some intracranial nervous tissue. The importance of axonal undulation has previously been considered, for example, in the context of biomechanics, where it has been shown that posture affects undulation properties. However, the importance of axonal undulation in the context of diffusion MR measurements has not been investigated. Using an analytical model and Monte Carlo simulations of water diffusion, this study compared undulating and straight axons in terms of diffusion propagators, diffusion-weighted signal intensities and parameters derived from diffusion tensor imaging, such as the mean diffusivity (MD), the eigenvalues and the fractional anisotropy (FA). All parameters were strongly affected by the presence of undulation. The diffusivity perpendicular to the undulating axons increased with the undulation amplitude, thus resembling that of straight axons with larger diameters. Consequently, models assuming straight axons for the estimation of the axon diameter from diffusion MR measurements might overestimate the diameter if undulation is present. FA decreased from approximately 0.7 to 0.5 when axonal undulation was introduced into the simulation model structure. Our results indicate that axonal undulation may play a role in diffusion measurements when investigating, for example, the optic and sciatic nerves and the spinal cord. The simulations also demonstrate that the stretching or compression of neuronal tissue comprising undulating axons alters the observed water diffusivity, suggesting that posture may be of importance for the outcome of diffusion MRI measurements.

  13. Analytical Account for the Constant Magnetic Field Effect on the Undulator Radiation Spectrum (United States)

    Zhukovsky, K. V.


    The effect of the constant magnetic field on the planar undulator radiation (UR) is studied. We employ generalized special functions to investigate the UR intensity and spectrum, calculate critical strength of the constant field, affecting the electron motion in undulators. The influence of the Earth magnetism on several real undulators' emission and spectrum is investigated.

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

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Ipsen, John Hjorth


    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...

  15. Development of optimization method for plate heat exchanger with undulation

    Directory of Open Access Journals (Sweden)

    Dvořák Václav


    Full Text Available The article deals with optimization of undulated heat transfer surface of plate heat exchanger. The goal of optimization is not only to increase effectiveness of heat transfer but also to reduce the pressure drop. A combined pattern of undulation which combines herringbone pattern and wavy pattern was optimized and best values of four parameters were found; angle of herringbone pattern, number, phase and amplitude of longitudinal waves of wavy pattern. The optimization procedure looked for maximum of objective function which was a linear combination of effectiveness and pressure drop. We used simple Monte Carlo method and the optimum was searched for four values of reference pressure drop. Four different optimization were run and we investigated the effect of various definition of objective function and parameters of undulation. It was found that during optimization of combined pattern, the herringbone pattern is more favoured than wavy pattern. It is caused by the fact that herringbone pattern was described by the only one free parameter, which was the angle of undulation, and therefore it is more likely to be found by a stochastic method. This assumption was confirmed when simple wavy pattern was optimized and higher values of objective function and effectiveness were found.

  16. Test of an undulated vacuum chamber for the ISR

    CERN Multimedia


    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.

  17. 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


    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.

  18. A comparison of geoid undulations for west central Greenland

    DEFF Research Database (Denmark)

    Roman, D.R.; Csatho, B.; Jezek, K.C.;


    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 ge......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 levelling 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...

  19. An Electromagnetic Undulator for the Far Infrared at ELBE

    CERN Document Server

    Dekorsy, Thomas; Grosse, Eckart; Michel, Peter; Seidel, Wolfgang; Wolf, Andreas; Wuensch, Rudi


    The first lasing in the mid IR at the ELBE FEL allows us to specify the parameters of a new undulator for longer wavelengths to complement the U27 undulator which is useful up to about 25 microns. In the longer wavelength region FELs constitute a unique radiation source with appealing properties. Radiation quanta in this range (2 - 10 THz) are appropriate for the low-energy spectroscopy of various interesting modes in solid state quantum structures as well as in complex biological systems. Their study establishes the basis for understanding phenomena in semiconductors and elucidating biological processes of interest for medical innovations. We envisage an electromagnetic undulator with a period of 90 - 100 mm. Using the ELBE beam IR light from 20 to 150 microns and beyond can be produced. To keep the transverse beam extension small the IR beam is to be guided by a partial waveguide inside the undulator. Appropriate bifocal resonator mirrors minimize the mode coupling losses at the exits of the waveguide. Deta...

  20. Monochromator on a synchrotron undulator source for liquid surface studies

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Freund, A.K.


    a monochromator made of a beryllium mosaic crystal using the (002) reflection in Laue geometry placed in undulator beams of DORIS III at the Hamburger Synchrotronstrahlungslabor and of the European Synchrotron Radiation Facility. An analysis of the diffraction properties in terms of mosaic spread, heat load...

  1. 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.


    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.

  2. High Efficiency Electron-Laser Interactions in Tapered Helical Undulators (United States)

    Duris, Joseph Patrick

    Efficient coupling of relativistic electron beams with high power radiation lies at the heart of advanced accelerator and light source research and development. The inverse free electron laser is a stable accelerator capable of harnessing very high intensity laser electric fields to efficiently transfer large powers from lasers to electron beams. In this dissertation, we first present the theoretical framework to describe the interaction, and then apply our improved understanding of the IFEL to the design and numerical study of meter-long, GeV IFELs for compact light sources. The central experimental work of the dissertation is the UCLA BNL helical inverse free electron laser experiment at the Accelerator Test Facility in Brookhaven National Laboratory which used a strongly tapered 54cm long, helical, permanent magnet undulator and a several hundred GW CO2 laser to accelerate electrons from 52 to 106MeV, setting new records for inverse free electron laser energy gain (54MeV) and average accelerating gradient (100MeV/m). The undulator design and fabrication as well as experimental diagnostics are presented. In order to improve the stability and quality of the accelerated electron beam, we redesigned the undulator for a slightly reduced output energy by modifying the magnet gap throughout the undulator, and we used this modified undulator to demonstrated capture of >25% of the injected beam without prebunching. In the study of heavily loaded GeV inverse free electron lasers, we show that a majority of the power may be transferred from a laser to the accelerated electron beam. Reversing the process to decelerate high power electron beams, a mechanism we refer to as tapering enhanced stimulated superradiant amplification, offers a clear path to high power light sources. We present studies of radiation production for a wide range of wavelengths (10mum, 13nm, and 0.3nm) using this method and discuss the design for a deceleration experiment using the same undulator used

  3. Magnetic performance of DEVU25.20h undulator at IDDL, DAVV,India (United States)

    Mishra, G.; Gehlot, Mona; Sharma, Geetanjali; Khullar, Roma


    In this paper, we describe the design development and magnetic performance of a prototype DEVU25.20h, variable gap hybrid undulator at IDD laboratory, DAVV, Indore, India. The undulator is NdFeB based hybrid undulator with twenty five period and 20 mm each period length. Low cost M35 grade cobalt steel is used as the pole material of the undulator. The abc coefficients of the new pole material is prescribed and the measured performance and characteristics of the undulator is evaluated using RADIA. The detailed design parameters and performance indicators are summarized in Table 1 and Table 2 respectively.

  4. 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


    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 ...

  5. 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)


    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.

  6. 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: [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)


    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.

  7. Vertically polarizing undulator with dynamic compensation of magnetic forces (United States)

    Strelnikov, N.; Vasserman, I.; Xu, J.; Jensen, D.; Schmidt, O.; Trakhtenberg, E.; Suthar, K.; Moog, E. R.; Pile, G.; Gluskin, E.


    As part of the R&D program of the LCLS-II project, a novel 3.4-meter-long undulator prototype with horizontal magnetic field and dynamic force compensation has recently been developed at the Advanced Photon Source (APS). Previous steps in this development were the shorter 0.8-meter-long and 2.8-meter-long prototypes. Extensive mechanical and magnetic testing were carried out for each prototype, and each prototype was magnetically tuned using magnetic shims. The resulting performance of the 3.4-meter-long undulator prototype meets all requirements for the LCLS-II insertion device, including limits on the field integrals, phase errors, higher-order magnetic moments, and electron-beam trajectory for all operational gaps, as well as the reproducibility and accuracy of the gap settings.

  8. Magnetic design of a 14 mm period prototype superconducting undulator (United States)

    Gehlot, Mona; Mishra, G.; Trillaud, Frederic; Sharma, Geetanjali


    In this paper we report the design of a 14 mm period prototype superconducting undulator that is under fabrication at Insertion Device Development Laboratory (IDDL) at Devi Ahilya Vishwavidyalaya, Indore, India. The field computations are made in RADIA and results are presented in an analytical form for computation of the on axis field and the field on the surface of the coil. On the basis of the findings, a best fit is presented for the model to calculate the field dependence on the gap and the current density. The fit is compared with Moser-Rossmanith formula proposed earlier to predict the magnetic flux density of a superconducting undulator. The field mapping is used to calculate the field integrals and its dependence on gap and current densities as well.

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

    CERN Document Server

    Campbell, L T; Reiche, S


    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.

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

    CERN Document Server

    López, Gustavo V


    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.

  11. Modulated Electron Bunch with Amplitude Front Tilt in an Undulator

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni


    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 radi...

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

    CERN Document Server

    Jeff, A; Welsch, CP


    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...

  13. 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


    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.

  14. Antiaging activity of low molecular weight peptide from Paphia undulate (United States)

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


    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.


    Energy Technology Data Exchange (ETDEWEB)



    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).

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

    CERN Document Server

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


    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...

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

    Institute of Scientific and Technical Information of China (English)


    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.

  18. An analysis on optimization of undulator in self-seeding free electron laser

    CERN Document Server

    Qika, Jia


    A simple analysis is given for optimum length of undulator in self-seeding free electron laser (FEL). The obtained relations show the correlation between the undulator length and the system parameters. The power required for the seeding in the second part undulator and overall efficiency to monochromatizating the seeding settle on the length of the first part undulator; the magnitude of seeding power dominates the length of the second part undulator; the whole length of the undulators in self-seeding FEL is determined by the overall efficiency to get coherent seed, it is about half as long again as that of SASE, not including the dispersion section. The requirement of the dispersion section strength is also analyzed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Matthias


    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent


    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.

  1. Ripple reduction control of the undulation pump total artificial heart. (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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wootton, Kent


    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.

  3. 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.


    This paper deals with field measurements of undulations of the bottom bathymetry along an otherwise straight coast at the Danish West Coast. Two bathymetric datasets and two time series of wave measurements are used in order to determine the following properties: the offshore extent of shoreline...... 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...... with undulations on the depth contours between −5m and +2m relative to mean sea level. In the other data set, only undulations on the depth contours between −1m and +1m are well correlated with the shoreline undulations. The main difference in the wave climate between the two locations is the orientation...

  4. 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)


    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.

  5. Investigation of the polarization state of dual APPLE-II undulators. (United States)

    Hand, Matthew; Wang, Hongchang; Dhesi, Sarnjeet S; Sawhney, Kawal


    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.

  6. Investigation of a method to calculate spontaneous radiation spectra from relativistic electrons in undulators

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming-Zhi; HE Jian-Hua


    Undulators are key devices to produce brilliant synchrotron radiation at the synchrotron radiation facilities.In this paper we present a numerical computing method,including the computing program that has been developed to calculate the spontaneous radiation emitted from relativistic electrons in undulators by simulating the electrons' trajectory.The effects of electron beam emittance and energy spread have also been taken into account.Comparing with other computing methods available at present,this method has a few advantages with respect to several aspects.It can adopt any measured or arbitrarily simulated 3D magnetic field and arbitrary electron beam pattern for the calculation and it's able to analyze undulators of any type of magnetic structure.It's expected to predict precisely the practical radiation spectrum.The calculation results of a short period in-vacuum undulator and an EllipticaUy Polarized Undulator (EPU) at Shanghai Synchrotron Radiation Facility (SSRF) are presented as examples.

  7. Photon emission by ultra-relativistic positrons in crystalline undulators: the high-energy regime

    CERN Document Server

    Krause, W; Solov'yov, A V; Greiner, W


    This paper discusses the undulator radiation emitted by high-energy positrons during planar channeling in periodically bent crystals. We demonstrate that the construction of the undulator for positrons with energies of 10 GeV and above is only possible if one takes into account the radiative energy losses. The frequency of the undulator radiation depends on the energy of the particle. Thus the decrease of the particle's energy during the passage of the crystal should result in the destruction of the undulator radiation regime. However, we demonstrate that it is possible to avoid the destructive influence of the radiative losses on the frequency of the undulator radiation by the appropriate variation of the shape of the crystal channels. We also discuss a method by which, to our mind, it would be possible to prepare the crystal with the desired properties of its channels.

  8. Forced resonant undulation in the deep Mascarene Basin (United States)

    Warren, Bruce A.; Whitworth, Thomas; LaCasce, Joseph H.

    Current meters moored for 19.5 months at Lat. 20°S in the deep water of the western Mascarene Basin recorded a distinct, large-amplitude [O(10 cm s -1)] undulation of bimonthly period, propagating westward at 7 cm s -1. Its characteristics demonstrate that it was a barotropic Rossby wave of relatively large meridional scale. Simple theory accounts for it as having been forced by local wind-stress curl at one of the resonant frequencies of the Mascarene Basin. A sharp bimonthly peak is also prominent in spectra of TOPEX/POSEIDON sea-surface height in the Mascarene Basin, but is not seen to the eastward, as is consistent with the local generation. Fluctuations of 45-day period reported earlier in the upper ocean just northeast of Madagascar might have been generated through a similar process, but with frequency shifted by the South Equatorial Current.

  9. 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)


    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.

  10. Development and testing of a prototype superconducting undulator (United States)

    Jan, J. C.; Hwang, C. S.; Lin, F. Y.; Chang, C. H.


    A prototype superconducting undulator with a 1-m magnet array, a magnet period of 15 mm and a magnet gap of 5.6 mm was fabricated to test the performance of the magnetic field and to investigate related issues. The mechanical precision of the entire iron pole construction is within 30 μm. The electric insulation was enhanced with Kapton tape on the entire magnet array between the wire and the iron. A dummy beam duct was assembled with the magnet array and tested in the test dewar. A cryogenic Hall-probe measurement system with a rail guider was assembled with the test dewar to measure the on-axis field distribution. A UHV beam duct was developed and tested in a separate environment to ensure the reliability and to test the aging effect. In this paper, the concept of the magnet design, the related technical issues, the performance of the magnetic field and the magnet training behavior is discussed.

  11. 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


    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.

  12. CSEM-Steel hybrid wiggler/undulator magnetic field studies

    Energy Technology Data Exchange (ETDEWEB)

    Halbach, K.; Hoyer, E.; Marks, S.; Plate, D.; Shuman, D.


    Current design of permanent magnet wiggler/undulators use either pure charge sheet equivalent material (CSEM) or the CSEM-Steel hybrid configuration. Hybrid configurations offer higher field strength at small gaps, field distributions dominated by the pole surfaces and pole tuning. Nominal performance of the hybrid is generally predicted using a 2-D magnetic design code neglecting transverse geometry. Magnetic measurements are presented showing transverse configuration influence on performance, from a combination of models using CSEMs, REC (H/sub c/ = 9.2 KOe) and NdFe (H/sub c/ = 10.7 kOe), different pole widths and end configurations. Results show peak field improvement using NdFe in place of REC in identical models, gap peak field decrease with pole width decrease (all results less than computed 2-D fields), transverse gap field distributions, and importance of CSEM material overhanging the poles in the transverse direction for highest gap fields. 3 refs., 6 figs.

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


    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.

  14. 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


    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.

  15. Radiation from relativistic electrons in "light" and in conventional undulators. Classical and quantum approaches (United States)

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


    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.

  16. A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University (United States)

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


    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.

  17. 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


    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.

  18. Wave scattering by undulating bed topography in a two-layer ocean

    Institute of Scientific and Technical Information of China (English)



    The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.

  19. 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


    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.

  20. Spectrum splitting for fast polarization switching of undulator radiation. (United States)

    Kinjo, Ryota; Tanaka, Takashi


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tantawi, S.; Dolgashev, V.; Nantista, C.; /SLAC; Pellegrini, C.; Rosenzweig, J.; Travish, G.; /UCLA


    High power microwave sources at X-Band, delivering 400 to 500 of megawatts for about 400 ns, have been recently developed. These sources can power a microwave undulator with short period and large gap, and can be used in short wavelength FELs reaching the nm region at a beam energy of about 1 GeV. We present here an experiment designed to demonstrate that microwave undulators have the field quality needed for high gain FELs.

  2. Electromagnetic design, implementation and test of a superconducting undulator with a transverse gradient field amplitude

    Energy Technology Data Exchange (ETDEWEB)

    Afonso Rodriguez, Veronica


    This thesis describes the development of a novel superconducting transversal gradient undulator (TGU) designed to form a compact, highly brilliant laser-wakefield accelerator (LWFA) driven radiation source. A TGU in combination with a dispersive beam transport line can be employed to produce undulator radiation with natural bandwidth despite the large energy spread of the LWFA. This thesis documents the construction, first tests and characterization of the full-scale TGU.

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

    CERN Document Server

    Mak, Alan; Faatz, Bart; Werin, Sverker


    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.

  4. Patterns in biofilms: From contour undulations to fold focussing (United States)

    Ben Amar, Martine; Wu, Min


    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.

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

    CERN Document Server

    Kuroda, R


    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...

  6. Geometric Mechanics Reveals Optimal Complex Terrestrial Undulation Patterns (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.

  7. Long wavelength undulations dominate dynamics in large surfactant membrane patches (United States)

    Lipfert, Frederik; Holderer, Olaf; Frielinghaus, Henrich; Appavou, Marie-Sousai; Do, Changwoo; Ohl, Michael; Richter, Dieter


    By exposing microemulsions to small (80 nm diameter) and large (500 nm) disk shaped clay particles we were able to show the presence of long wavelength undulations that only occur for large membrane patches. A combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) experiments have been applied to study microemulsions. These, consisting of D2O, d-decane and the surfactant C10E4, were used in connection with Laponite (small) and Nanofil (large) clay. To our knowledge our experiments show for the first time that the clay platelets induce lamellar ordering adjacent to the clay discs in the otherwise bicontinuous microemulsion. This is due to the fact that in purely structural investigations, radial averaging smears out the signature of the lamellar phase. For thermodynamically fluctuating membranes near interfaces the theory of Seifert predicts a cross-over of the dispersion relationship from k2 to a k3-dependence. With the correlation length of the membrane patches being confined by the dimension of the clay platelets we were able to show that this in fact takes place but is only present for the larger Nanofil particles.

  8. Computation of the brightness of the variably-polarizing undulator

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G.; Torre, A. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dipt. Innovazione; Schettini, G. [Rome, Univ. `La Sapienza` (Italy). Dip. di Ingegneria Elettronica; Carpanese, M.


    Undulators, producing variably polarized radiation, generate magnetic fields which induce different types of electron motion (vertically, horizontally sinusoidal and helical). The properties of the emitted radiation reflect the complexity of the motion and cannot be described with the method based on the conventional Bessel functions expansion. It`s shown that the problem can be overcome by exploiting a method which employs generalized forms of Bessel functions. The proposed technique provides an effective tool to analyze the properties of the emitted radiation. [Italiano] Ondulatori con polarizzazione variabile generano campi magnetici che inducono tipi differenti di moto degli elettroni (sinusoidale in direzione verticale o orizzontale, elicoidale). Le proprieta` della radiazione emessa riflettono la complessita` del moto e non possono essere derivate utilizzando il metodo della espansione in funzioni di Bessel ordinarie. Si dimostra come il problema possa essere superato utilizzando un metodo che utilizza forme generalizzate di funzioni di Bessel. Il metodo proposto fornisce una tecnica efficacie per l`analisi delle proprieta` della radiazione emessa.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  10. A new field correction scheme for superconducting undulators by modification the iron pole geometry

    Energy Technology Data Exchange (ETDEWEB)

    Chunjarean, S [Suranaree University of Technology (SUT), Nakhon Ratchasima (Thailand); Jan, J C; Hwang, C H [National Synchrotron Radiation Research Center (NSRRC), Hsinchu Science Park, Taiwan (China); Lin, P H [Synchrotron Light Research Institute (Public Organization), SLRI, Nakhon Ratchasima (Thailand); Wiedemann, H, E-mail: [Stanford University, Stanford, CA (United States)


    Permanent magnet material undulators are used in many research facilities worldwide to produce high brightness synchrotron radiation for basic and applied research. Their effectiveness is limited in low energy storage rings because of a lack of sufficient magnetic field intensity. Superconducting undulators can produce higher fields and therefore higher photon energies, especially at lower electron beam energies. Undulator radiation is emitted in a line spectrum where the fundamental wavelength is determined by the undulator period and strength, beam energy and harmonic number. For a given beam energy, use of these higher harmonics is desirable, because they allow the provision of higher photon energies as high as soft or hard x-rays from 1 to 10 keV. The photon flux in such harmonics is however strongly dependent on the integrity of the periodic properties of the magnetic field. Small field and phase errors will reduce the photon intensity dramatically. Correction methods as employed for permanent magnet material undulators are not applicable in superconducting undulators. In this paper, we discuss a new approach for field corrections based on a variation of the magnetic field saturation properties of individual poles. We demonstrate its efficiency in ensuring photon fluxes which are close to theoretical expectations.

  11. Impact of a Vertically Polarized Undulator on LCLS Hard X-ray Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, David [SLAC National Accelerator Lab., Menlo Park, CA (United States)


    The LCLS-II project will install two variable gap, horizontally polarized undulators into the LCLS undulator hall. One undulator is designed to produce soft x-rays spanning an energy range of 200-1250 eV (SXU) while the other is designed for the hard spectral range of 1-25 keV (HXU). The hard x-ray LCLS instruments (X-ray Pump- Probe [XPP], X-ray correlation Spectroscopy [XCS], Coherent X-ray Imaging [CXI], Matter in Extreme Conditions [MEC]) will be repurposed to operate on the HXU line while two new soft x-ray beamlines will be created for the SXU line. An alternate HXU undulator design is being considered that could provide advantages over the present design choice. In particular, the project team is collaborating with Argonne National Laboratory to develop a vertically polarized undulator (VPU). A 1-m prototype VPU device was successfully constructed this year and a full size prototype is in process. A decision to alter the project baseline, which is the construction of a horizontally polarized device, must be made in the coming weeks to not impact the present project schedule. Please note that a change to the soft x-ray undulator is not under discussion at the moment.

  12. Improvement of the crossed undulator design for effective circular polarization control in X-ray FELs

    Energy Technology Data Exchange (ETDEWEB)

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


    The production of X-ray radiation with a high degree of circular polarization constitutes an important goal at XFEL facilities. A simple scheme to obtain circular polarization control with crossed undulators has been proposed so far. In its simplest configuration the crossed undulators consist of pair of short planar undulators in crossed position separated by an electromagnetic phase shifter. An advantage of this configuration is a fast helicity switching. A drawback is that a high degree of circular polarization (over 90 %) can only be achieved for lengths of the insertion devices significantly shorter than the gain length, i.e. at output power significantly lower than the saturation power level. The obvious and technically possible extension considered in this paper, is to use a setup with two or more crossed undulators separated by phase shifters. This cascade crossed undulator scheme is distinguished, in performance, by a fast helicity switching, a high degree of circular polarization (over 95%) and a high output power level, comparable with the saturation power level in the baseline undulator at fundamental wavelength. We present feasibility study and exemplifications for the LCLS baseline in the soft X-ray regime. (orig.)

  13. Orbital motion in generalized static fields of FELs accounting for axial magnetic field, beam forces, undulator and external focusing

    Energy Technology Data Exchange (ETDEWEB)

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


    Various types of undulators with or without axial magnetic field are used in FELs. Supplementary beam focusing can be applied by wedging, inclining or profiling pole faces of plan undulators or superposing external focusing magnetic fields in addition to undulator own focusing. Space-charge forces influence significantly particle motion in high-current, low-energy electron beams. Finally, one can use simultaneously two or more different undulators for some specific purpose: more efficient and selective higher harmonics generation, changing polarization types and direction, gain enhancement in double-period undulator etc. All these cases can be treated by solving the generalized equations of transverse orbital motion in a linear approximation, which is widely used for orbit calculation, gives sufficient accuracy for practical purposes and allows to consider many variants and optimize the chosen one. The undulator field is described as a field of two plane undulators with mutually orthogonal fields and an arbitrary axial (phase) shift between them. Various values of the phase shift correspond to right- or left-handed helical undulators, plane undulator of different polarization etc. The general formulae are reduced to forms that allow easier examination of particular cases: planar or helical undulator combined with axial magnetic field or without it, gyroresonance, limiting beam current, polarization etc.

  14. Short and medium-term evolution of shoreline undulations on curvilinear coasts (United States)

    López-Ruiz, Alejandro; Ortega-Sánchez, Miguel; Baquerizo, Asunción; Losada, Miguel A.


    This article proposes a one-line type model to explain the formation and evolution of shoreline undulations on circular or elliptic curvilinear coasts, such as littoral spits. The model takes into account the variation of the surf zone width stemming from the convergence and divergence of the waves propagating over a conical bathymetry with a small radius of curvature. The alongshore sediment transport varies with the angle formed by the wave crests and the coastline, as well as with surf zone width and sediment grain size. This model was applied to the shoreline undulations observed at the mouth of the River Guadalquivir (Gulf of Cádiz, Spain) and those at El Puntal Spit (Cantabrian Sea, Spain). In the first case, the model was forced with several sets of five-year wave climate simulations. At the El Puntal Spit, three different wave conditions, corresponding to the growth, saturation, and decay stages of the undulations, were simulated. In both cases, a net longitudinal growth of the spits was observed. Despite simplifications, the amplitude and wavelength of the shoreline undulations agree with the observations. Furthermore, both the zone and development time of the shoreline undulations can be estimated. The mechanism proposed for their generation and evolution may be complementary to other mechanisms, such as the instability mechanism of the coastline associated with high-angle waves.

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

    CERN Document Server

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni


    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 ...

  16. Radiation-induced magnetization reversal causing a large flux loss in undulator permanent magnets. (United States)

    Bizen, Teruhiko; Kinjo, Ryota; Hasegawa, Teruaki; Kagamihata, Akihiro; Kida, Yuichiro; Seike, Takamitsu; Watanabe, Takahiro; Hara, Toru; Itoga, Toshiro; Asano, Yoshihiro; Tanaka, Takashi


    We report an unexpectedly large flux loss observed in permanent magnets in one of the undulators operated in SACLA, the x-ray free electron laser facility in Japan. Characterizations of individual magnets extracted from the relevant undulator have revealed that the flux loss was caused by a homogeneous magnetization reversal extending over a wide area, but not by demagnetization of individual magnets damaged by radiation. We show that the estimated flux-loss rate is much higher than what is reported in previous papers, and its distribution is much more localized to the upstream side. Results of numerical and experimental studies carried out to validate the magnetization reversal and quantify the flux loss are presented, together with possible countermeasures against rapid degradation of the undulator performance.

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

    Institute of Scientific and Technical Information of China (English)

    Kin Huat Low


    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.

  18. 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


    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.

  19. An ultracompact X-ray source based on a laser-plasma undulator. (United States)

    Andriyash, I A; Lehe, R; Lifschitz, A; Thaury, C; Rax, J-M; Krushelnick, K; Malka, V


    The capability of plasmas to sustain ultrahigh electric fields has attracted considerable interest over the last decades and has given rise to laser-plasma engineering. Today, plasmas are commonly used for accelerating and collimating relativistic electrons, or to manipulate intense laser pulses. Here we propose an ultracompact plasma undulator that combines plasma technology and nanoengineering. When coupled with a laser-plasma accelerator, this undulator constitutes a millimetre-sized synchrotron radiation source of X-rays. The undulator consists of an array of nanowires, which are ionized by the laser pulse exiting from the accelerator. The strong charge-separation field, arising around the wires, efficiently wiggles the laser-accelerated electrons. We demonstrate that this system can produce bright, collimated and tunable beams of photons with 10-100 keV energies. This concept opens a path towards a new generation of compact synchrotron sources based on nanostructured plasmas.

  20. High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator (United States)

    Sudar, N.; Musumeci, P.; Duris, J.; Gadjev, I.; Polyanskiy, M.; Pogorelsky, I.; Fedurin, M.; Swinson, C.; Kusche, K.; Babzien, M.; Gover, A.


    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, supported by simulations of the radiation field evolution, 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.

  1. 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


    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.

  2. 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


    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.

  3. Condenser for Koehler-like illumination in transmission x-ray microscopes at undulator sources (United States)

    Vogt, Ulrich; Lindblom, Magnus; Charalambous, Pambos; Kaulich, Burkhard; Wilhein, Thomas


    We report on a novel condenser for full-field transmission x-ray microscopes that use synchrotron radiation from an undulator source. The condenser produces a Koehler-like homogeneous intensity distribution in the sample plane and eliminates object illumination problems connected with the high degree of spatial coherence in an undulator beam. The optic consists of a large number of small linear diffraction gratings and is therefore relatively easy to manufacture. First imaging experiments with a prototype condenser were successfully performed with the Twinmic x-ray microscope at the Elettra synchrotron facility in Italy.

  4. Fast Polarization Switching Demonstration Using Crossed-Planar Undulator in a Seeded Free Electron Laser

    CERN Document Server

    Deng, Haixiao; Feng, Lie; Feng, Chao; Chen, Jianhui; Liu, Bo; Wang, Xingtao; Lan, Taihe; Wang, Guanglei; Zhang, Wenyan; Liu, Xiaoqing; Zhang, Meng; Lin, Guoqiang; Zhang, Miao; Wang, Dong; Zhao, Zhentang


    Fast polarization switching of light sources is required over a wide spectral range to investigate the symmetry of matter. In this Letter, we report the first experimental demonstration of the crossed-planar undulator technique at a seeded free-electron laser, which holds great promise for the full control and fast switching of the polarization of short-wavelength radiation. In the experiment, the polarization state of the coherent radiation at the 2nd harmonic of the seed laser is switched successfully. The experiment results confirm the theory, and pave the way for applying the crossed-planar undulator technique for the seeded X-ray free electron lasers.

  5. 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)


    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.

  6. 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)


    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.

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

    DEFF Research Database (Denmark)

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


    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...

  8. End field formation in planar hybrid undulators to ensure gap independence of the first and second field integrals

    Energy Technology Data Exchange (ETDEWEB)

    Papadichev, V.A. [P.N. Lebedev Physical Institute, RAS, 53 Leninsky Prospect, 119991 Moscow (Russian Federation)]. E-mail:; Rybalchenko, G.V. [P.N. Lebedev Physical Institute, RAS, 53 Leninsky Prospect, 119991 Moscow (Russian Federation)


    Magnetic field amplitude in pure permanent magnet (PPM) or hybrid undulators is varied by changing the gap. It is necessary to ensure that for all gaps the deviation of the first and second field integrals from ideal be sufficiently small, especially in the XFEL project where dozens of undulator sections, each about 5-m long, are to be used. Since a high field is required, a hybrid undulator should be used. In this paper, field calculations for such an undulator were carried out using the 'Radia' code. Unlike a PPM undulator scheme, hybrid ones require more sophisticated schemes of minimizing field integrals because of complicated redistribution of magnetic flux at the undulator ends with changing gap. Saturation of iron poles makes solution of the problem more difficult. Both effects were studied and several compensating methods were found. Parameters of the permanent magnets and iron poles of the first and last end-field-forming undulator periods were varied in order to change the form and mean value of the first and second integrals versus undulator gap.

  9. Matched injection in a helical undulator taking into account the orbit amplitude and the longitudinal magnetic field

    CERN Document Server

    Papadichev, V A


    Helical undulators are widely used in FELs because they are inexpensive and easy to fabricate. Also, because field amplitudes can be conveniently adjusted with high accuracy. Their main weakness is their use of adiabatic input and output (up to 10 periods each) for matched injection (ejection) of the electron beam in the undulator field. This leads to considerable lengthening of the undulator and optical resonator, without simultaneously providing, in a number of cases, the required injection accuracy (due to some angle error and failure to account for orbit amplitude). Here alternative methods of matched injection are described that take into account orbit amplitude and external magnetic field. The length of correcting elements does not exceed one-half of the undulator period. When the overall length of the helical undulator is large, their application permits its realization in the form of a set of successive sections with free straight gaps in which devices can be placed for measuring beam parameters and c...

  10. Transfer of the magnetic axis of an undulator to mechanical fiducial marks of a laser tracker system

    Energy Technology Data Exchange (ETDEWEB)

    Ketenoğlu, Bora [Department of Engineering Physics, Ankara University, Tandoğan, Ankara 06100 (Turkey); European XFEL, Albert-Einstein-Ring 19, Hamburg 22761 (Germany); Englisch, Uwe; Li, Yuhui; Wolff-Fabris, Frederik [European XFEL, Albert-Einstein-Ring 19, Hamburg 22761 (Germany); Benecke, Wolf; Noak, Martin; Prenting, Johannes; Schloesser, Markus [Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, Hamburg 22607 (Germany); Pflueger, Joachim, E-mail: [European XFEL, Albert-Einstein-Ring 19, Hamburg 22761 (Germany)


    The exact geometric location of the magnetic centers of sensors or sensor systems using Hall probes or pick-up coils is usually not known with high precision. In order to transfer the high spatial accuracy of magnetic measurements to external mechanic fiducials a device called “Magnetic Landmark” was developed and is described in this report. Its purpose is to establish the exact relation between “magnetic” coordinates used on magnetic measurement systems and “mechanic” coordinates used for alignment. The landmark consists of a permanent magnet configuration, which generates a field distribution with well-defined zero crossings in two orthogonal directions, which can be exactly localized with micrometer precision using magnetic measurement systems. For the “mechanic” measurements several redundant monuments for laser fiducials can be used. Using flip tests for the magnetic as well as mechanic measurements the center positions are determined in magnetic and mechanic coordinates. Using them the relation between the magnetic and surveying coordinates can be established with high accuracy. This report concentrates on the description of the landmark. A thorough analysis on achievable accuracy is presented. The method was developed for the alignment of the 91 undulator segments needed for the European XFEL but can be applied to other magnet systems as well.

  11. Microwave Undulators and Electron Generators for New-Generation Free-Electron Lasers (United States)

    Abubakirov, E. B.; Bandurkin, I. V.; Vikharev, A. A.; Kuzikov, S. V.; Rozental, R. M.; Savilov, A. V.; Fedotov, A. E.


    We discuss possible applications of relativistic pulsed microwave electronic devices in physics and engineering of modern free-electron lasers. In particular, the possibilities of using high-power millimeter-wave radiation pulses for electron pitching in the operating space of the laser (in a microwave undulator), as well as for cooling and focusing of electron bunches, are considered.

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

    DEFF Research Database (Denmark)

    Mortensen, Bo


    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...

  13. High accuracy measurements of magnetic field integrals for the european XFEL undulator systems (United States)

    Wolff-Fabris, Frederik; Viehweger, Marc; Li, Yuhui; Pflüger, Joachim


    Two high accuracy moving wire (MW) measurement systems based on stretched wire technique were built for the European XFEL (XFEL.EU). They were dedicated to monitor, tune and improve the magnetic field integrals properties during the serial production of the undulator segments, phase shifters and air coil correctors for XFEL.EU. For the magnetic tuning of phase shifters and the calibration of the air coils correctors a short portable MW measurement bench was built to measure first field integrals in short devices with magnetic length of less than about 300 mm and with an ultimate accuracy much better than 1 G cm (0.001 T mm). A long MW measurement setup was dedicated to obtain the total first and second field integrals on the 5-meters long undulator segments with accuracy of about 4 G cm (0.004 T mm) and 2000 G cm2 (20 T mm2) for the 1st and 2nd field integrals, respectively. Using these data a method was developed to compute the proper corrections for the air coils correctors used at both extremities so that zero first and second field integrals for an undulator segment are obtained. It is demonstrated that charging air coils correctors with these corrections results in near zero effect to the electron trajectory in the undulator systems and consequently no negative impact on the self-amplified spontaneous emission (SASE) process should occur.

  14. 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)


    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.

  15. A study on low emittance injector and undulator for PAL-XFEL

    Institute of Scientific and Technical Information of China (English)

    J.Hong; J.-H.Han; S.J.Park; Y.G.Jung; D.E.Kim; H.-S.Kang; J.Pflueger


    For the success of PAL-XFEL, two critical systems, namely a low emittance injector and a variable gap out-vacuum undulator, are under development. In order to realize the target emittance of the PAL-XFEL injector we carried out an optimization study of various parameters, such as the laser beam transverse profile, the laser pulse length, the laser phase,and the gun energy. The transverse emittance measured at the Injector Test Facility(ITF) is εx=0.48±0.01 mm mrad.An undulator prototype based on the EU-XFEL design and modified for PAL-XFEL was built and tested. A local-K pole tuning procedure was developed and tested. A significant reduction(90%) of the local-K fluctuation was observed. The requirement of undulator field reproducibility better than 2×10-4and the undulator gap setting accuracy below 1 μm were achieved for the prototype. The optical phase jitter after the pole height tuning at the tuning gap was calculated to be 2.6? rms, which satisfies the requirement of 5.0?.

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

    NARCIS (Netherlands)

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


    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

  17. 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.


    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.)

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

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


    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).

  19. 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)


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander


    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

  1. 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.


    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.

  2. 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


    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.

  3. Manufacture and Test of the Prototype 5 T Superconducting Undulator for the LHC Synchrotron Radiation Profile Monitor

    CERN Document Server

    MacCaferri, R; Tommasini, D; Venturini-Delsolaro, W


    A superconducting undulator wound with Nb-Ti based conductor, will be used in the LHC as a key part of the synchrotron radiation profile monitor system. Two undulators are needed, one per each circulating beam, providing 5 T in a 60 mm bore over two periods of 280 mm each. A full scale prototype has been designed and successfully tested in the end of 2004. In this paper, the electromagnetic and the mechanical design of the undulator are summarized. The fabrication of the prototype is described and the successful cold test results, both power test and magnetic flux density measurements, are reported.

  4. 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


    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

  5. Ice Velocity Mapping of Ross Ice Shelf, Antarctica by Matching Surface Undulations Measured by Icesat Laser Altimetry (United States)

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


    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.

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

    DEFF Research Database (Denmark)

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


    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....

  7. 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


    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...

  8. 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


    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.

  9. New beamline optics of the x-ray undulator BW1 at DORIS

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, U.; Frahm, R.; Guertler, P.; Schulte-Schrepping, H. [Deutsches Elektronen-Synchrotron, Hamburg (Germany). Hamburger Synchrotronstrahlungslabor


    The X-ray undulator BW1 at the storage ring DORIS is a high brightness source for the spectral range from 2 to 20 keV. The undulator beam is used by three experiments with different distances to the source. The new optical elements allow the adaptation of the focal lengths to the needs of the experimental set-ups. The optical concept consists of a premirror with different optical surfaces, a double crystal monochromator and a focusing second mirror. Sagittal focusing is achieved either by using the cylindrical part of the premirror or by a bend crystal for a monochromatic beam, meridional focusing is done with a pneumatic driven mirror bender for the second mirror.

  10. 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


    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.

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

    Indian Academy of Sciences (India)

    Vinit Kumar; Ganeshwar Mishra


    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.

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

    DEFF Research Database (Denmark)

    Kærgaard, Kasper Hauberg; Fredsøe, Jørgen


    The present work applies the shoreline model from part 1 to a real environment. In part 1, a numerical shoreline model which could handle the development of arbitrarily shaped shorelines was applied to consider the development of shoreline undulations on an unstable shoreline exposed to incoming...... 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 describe...

  13. Formation of undulated lamellar structure from ABC block terpolymer blends with different chain lengths (United States)

    Matsushita, Yushu; Suzuki, Jiro; Izumi, Yuuki; Matsuoka, Kohei; Takahashi, Shuji; Aoyama, Yoshitaka; Mihira, Tomohiro; Takano, Atsushi


    The effect of molecular weight distribution of ABC linear terpolymers on the formation of periodic structures was investigated. Three poly(isoprene-b-styrene-b-2-vinylpridine) triblockterpolymers with molecular weights of 26k, 96k, and 150k were blended variously. Three-phase, four-layer lamellar structures were observed when polydispersity index (PDI) was low, but it has been found that simple lamellar structure with flat surface transforms into an undulated lamellar one, where two interfaces, i.e., I/S and S/P, are both undulated, and they are synchronizing each other if PDI exceeds the critical value. This new structure could be formed due to the periodic and "weak" localization of three chains along the domain interfaces, which produces periodic surfaces with nonconstant mean curvatures. With further increase of PDI, the blend macroscopically phase-separated into different microphase-separated structures.

  14. Thermal analysis of the first canted-undulator front-end components at SSRF

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhongmin, E-mail:; Feng, Xinkang; Wang, Naxiu; Wu, Guanyuan; Zhang, Min; Wang, Jie


    The performance of three kinds of masks: pre-mask, splitter mask and fixed mask-photon shutter, used for the first canted-undulator front end under heat loads at SSRF, is studied. Because these components are shared with two beamlines, the X-rays from both dual undulators and bending magnets can strike on them. Under these complicated conditions, they will absorb much more thermal power than when they operate in usual beamline. So thermal and stress analysis is indispensable for their mechanical design. The method of applying the non-uniform power density using Ansys is presented. During thermal stress analysis, the normal operation or the worst possible case is considered. The finite element analyses results, such as the maximum temperature of the body and the cooling wall and the maximum stress of these components, show the design of them is reasonable and safe.

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

    Energy Technology Data Exchange (ETDEWEB)

    Anania, M. P. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); INFN, Laboratori Nazionali di Frascati, I-00044 Frascati (Italy); Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A., E-mail: [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Geer, S. B. van der; Loos, M. J. de [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands); Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A. [ASTeC, STFC, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Gillespie, W. A. [SUPA, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); MacLeod, A. M. [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee DD1 1HG (United Kingdom)


    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 × 10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1 × 10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/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 energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.

  16. Fast continuous energy scan with dynamic coupling of the monochromator and undulator at the DEIMOS beamline. (United States)

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


    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.

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

    CERN Document Server

    Kulish, Victor V; Gubanov, I V


    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.

  18. Influence of higher harmonics of the undulator in X-ray polarimetry and crystal monochromator design. (United States)

    Marx-Glowna, Berit; Schulze, Kai S; Uschmann, Ingo; Kämpfer, Tino; Weber, Günter; Hahn, Christoph; Wille, Hans Christian; Schlage, Kai; Röhlsberger, Ralf; Förster, Eckhart; Stöhlker, Thomas; Paulus, Gerhard G


    The spectrum of the undulator radiation of beamline P01 at Petra III has been measured after passing a multiple reflection channel-cut polarimeter. Odd and even harmonics up to the 15th order, as well as Compton peaks which were produced by the high harmonics in the spectrum, could been measured. These additional contributions can have a tremendous influence on the performance of the polarimeter and have to be taken into account for further polarimeter designs.

  19. 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)


    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.

  20. Undulating tubular liposomes through incorporation of a synthetic skin ceramide into phospholipid bilayers


    Xu, Peng; Tan, Grace; Zhou, Jia; He, Jibao; Lawson, Louise B.; McPherson, Gary L.; John, Vijay T.


    Non-spherical liposomes were prepared by doping L-α-phosphatidylcholine (PC) with ceramide VI (a skin lipid). Cryo-transmission electron microscopy shows the liposome shape changing from spherical to an undulating tubular morphology, when the amount ofceramide VI is increased. The formation of tubular liposomes is energetically favorableand is attributed to the association of ceramide VI with PC creating regions of lower curvature. Since ceramides are the major component of skin lipids inthe ...

  1. 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)


    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.

  2. 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


    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.

  3. Liquid X-ray scattering with a pink-spectrum undulator. (United States)

    Bratos, S; Leicknam, J-Cl; Wulff, M; Khakhulin, D


    X-ray scattering from a liquid using the spectrum from the undulator fundamental is examined as a function of the bandwidth of the spectrum. The synchrotron-generated X-ray spectrum from an undulator is 'pink', i.e. quasi-monochromatic but having a saw-tooth-shaped spectrum with a bandwidth from 1 to 15%. It is shown that features in S(q) are slightly shifted and dampened compared with strictly monochromatic data. In return, the gain in intensity is 250-500 which makes pink beams very important for time-resolved experiments. The undulator spectrum is described by a single exponential with a low-energy tail. The tail shifts features in the scattering function towards high angles and generates a small reduction in amplitude. The theoretical conclusions are compared with experiments. The r-resolved Fourier transformed signals are discussed next. Passing from q- to r-space requires a sin-Fourier transform. The Warren convergence factor is introduced in this calculation to suppress oscillatory artifacts from the finite qM in the data. It is shown that the deformation of r-resolved signals from the pink spectrum is small compared with that due to the Warren factor. The q-resolved and the r-resolved pink signals thus behave very differently.

  4. A Helical Undulator Wave-guide Inverse Free-Electron Laser (United States)

    Rosenzweig, J.; Bodzin, N.; Frigola, P.; Joshi, C.; Musumeci, P.; Pellegrini, C.; Tochitsky, S.; Travish, G.


    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.

  5. X-ray lithography using wiggler and undulator synchrotron-radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Neureuther, A.R.; Kim, K.J.; Thompson, A.C.; Hoyer, E.


    A systems design approach is used to identify feasible options for wiggler and undulator beam lines for x-ray lithography in the 0.5 to 0.2 linewidth region over 5 cm by 5 cm fields. Typical parameters from the Wiggler and Undulator in the Advanced Light Source designed at the Lawrence Berkeley Laboratory are used as examples. Moving from the conventional wavelengths of 4 to 9 A to very soft wavelengths around 15 A is shown to be very promising. The mask absorber thickness can be reduced a factor of three so that 0.2 features can be made with a 1:1 mask aspect ratio. The mask heating limited exposure time is also reduced a factor of three to 3 sec/cm/sup 2/. However, extremely thin beam line windows (1/4 mil Be) and mask supports (1 Si) must be used. A wiggler beam line design using a small slit window at a scanning mirror appears feasible. A unconventional, windowless differentially pumped beam line with dual deflecting mirrors could be used with an undulator source.

  6. 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


    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.

  7. 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)


    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.

  8. Self-assembly of colloidal particles in deformation landscapes of electrically driven layer undulations in cholesteric liquid crystals (United States)

    Varney, Michael C. M.; Zhang, Qiaoxuan; Senyuk, Bohdan; Smalyukh, Ivan I.


    We study elastic interactions between colloidal particles and deformation landscapes of undulations in a cholesteric liquid crystal under an electric field applied normal to cholesteric layers. The onset of undulation instability is influenced by the presence of colloidal inclusions and, in turn, layers' undulations mediate the spatial patterning of particle locations. We find that the bending of cholesteric layers around a colloidal particle surface prompts the local nucleation of an undulations lattice at electric fields below the well-defined threshold known for liquid crystals without inclusions, and that the onset of the resulting lattice is locally influenced, both dimensionally and orientationally, by the initial arrangements of colloids defined using laser tweezers. Spherical particles tend to spatially localize in the regions of strong distortions of the cholesteric layers, while colloidal nanowires exhibit an additional preference for multistable alignment offset along various vectors of the undulations lattice. Magnetic rotation of superparamagnetic colloidal particles couples with the locally distorted helical axis and undulating cholesteric layers in a manner that allows for a controlled three-dimensional translation of these particles. These interaction modes lend insight into the physics of liquid crystal structure-colloid elastic interactions, as well as point the way towards guided self-assembly of reconfigurable colloidal composites with potential applications in diffraction optics and photonics.

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Stephen


    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

  11. Matched injection in a helical undulator taking into account the orbit amplitude and the longitudinal magnetic field (United States)

    Papadichev, V. A.


    Helical undulators are widely used in FELs because they are inexpensive and easy to fabricate. Also, because field amplitudes can be conveniently adjusted with high accuracy. Their main weakness is their use of adiabatic input and output (up to 10 periods each) for matched injection (ejection) of the electron beam in the undulator field. This leads to considerable lengthening of the undulator and optical resonator, without simultaneously providing, in a number of cases, the required injection accuracy (due to some angle error and failure to account for orbit amplitude). Here alternative methods of matched injection are described that take into account orbit amplitude and external magnetic field. The length of correcting elements does not exceed one-half of the undulator period. When the overall length of the helical undulator is large, their application permits its realization in the form of a set of successive sections with free straight gaps in which devices can be placed for measuring beam parameters and correction of the trajectory.

  12. 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


    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.

  13. Spatial coherence of undulator radiation beyond the van Cittert-Zernike theorem

    CERN Document Server

    Takayama, Y; Miyahara, T; Kamada, S; Okamoto, W; Hatano, T; Tai, R; Kagoshima, Y


    A novel approximation for calculating the first-order spatial coherence of undulator radiation is presented. Since the far-field approximation is not used in the calculation, it is applicable even in the near-field region. Compared with numerical results based on the first principles, the approximation is proved to be quite reasonable. The spatial coherence measured at the Photon Factory, KEK is analyzed using the formula and the results are found to be consistent with the design value within experimental errors.

  14. Coupling impedance of an in-vacuum undulator. Measurement, simulation, and analytical estimation

    Energy Technology Data Exchange (ETDEWEB)

    Simaluk, Victor [Science and Technology Facilities Council (STFC), Harwell Campus, Oxford (United Kingdom). Diamond Light Source, Ltd.; Blednykh, Alexei [Brookhaven National Lab. (BNL), Upton, NY (United States); Fielder, Richard [Science and Technology Facilities Council (STFC), Harwell Campus, Oxford (United Kingdom). Diamond Light Source, Ltd.; Rehm, Guenther [Science and Technology Facilities Council (STFC), Harwell Campus, Oxford (United Kingdom). Diamond Light Source, Ltd.; Bartolini, Riccardo [Science and Technology Facilities Council (STFC), Harwell Campus, Oxford (United Kingdom). Diamond Light Source, Ltd.; Univ. of Oxford (United Kingdom)


    One of the important issues of the in-vacuum undulator design is the coupling impedance of the vacuum chamber, which includes tapered transitions with variable gap size. In order to get complete and reliable information on the impedance, analytical estimate, numerical simulations and beam-based measurements have been performed at Diamond Light Source, a forthcoming upgrade of which includes introducing additional insertion device (ID) straights. Moreover, the impedance of an already existing ID vessel geometrically similar to the new one has been measured using the orbit bump method. The measurement results in comparison with analytical estimations and numerical simulations are discussed in this paper.

  15. Coupling impedance of an in-vacuum undulator: Measurement, simulation, and analytical estimation (United States)

    Smaluk, Victor; Fielder, Richard; Blednykh, Alexei; Rehm, Guenther; Bartolini, Riccardo


    One of the important issues of the in-vacuum undulator design is the coupling impedance of the vacuum chamber, which includes tapered transitions with variable gap size. To get complete and reliable information on the impedance, analytical estimate, numerical simulations and beam-based measurements have been performed at Diamond Light Source, a forthcoming upgrade of which includes introducing additional insertion device (ID) straights. The impedance of an already existing ID vessel geometrically similar to the new one has been measured using the orbit bump method. The measurement results in comparison with analytical estimations and numerical simulations are discussed in this paper.

  16. Beam chopper For the Low-Energy Undulator Test Line (LEUTL) in the APS

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Y.; Wang, J.; Milton, S.; Teng, L. [and others


    The low-energy undulator test line (LEUTL) is being built and will be tested with a short beam pulse from an rf gun in the Advanced Photon Source (APS) at the Argonne National Laboratory. In the LEUTL a beam chopper is used after the rf gun to deflect the unwanted beam to a beam dump. The beam chopper consists of a permanent magnet and an electric deflector that can compensate for the magnetic deflection. A 30-kV pulsed power supply is used for the electric deflector. The chopper subsystem was assembled and tested for beamline installation. The electrical and beam properties of the chopper assembly are presented.

  17. Undulating tubular liposomes through incorporation of a synthetic skin ceramide into phospholipid bilayers. (United States)

    Xu, Peng; Tan, Grace; Zhou, Jia; He, Jibao; Lawson, Louise B; McPherson, Gary L; John, Vijay T


    Nonspherical liposomes were prepared by doping L-alpha-phosphatidylcholine (PC) with ceramide VI (a skin lipid). Cryo-transmission electron microscopy shows the liposome shape changing from spherical to an undulating tubular morphology, when the amount of ceramide VI is increased. The formation of tubular liposomes is energetically favorable and is attributed to the association of ceramide VI with PC creating regions of lower curvature. Since ceramides are the major component of skin lipids in the stratum corneum, tubular liposomes containing ceramide may potentially serve as self-enhanced nanocarriers for transdermal delivery.

  18. Undulant Universe

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  19. 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: [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)


    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.

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

    Institute of Scientific and Technical Information of China (English)

    Abdurrahim; A.D.Ghodke


    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.

  1. The onset of layer undulations in smectic A liquid crystals due to a strong magnetic field (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Mohsen Siahmansouri


    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.

  3. Automation of beam based alignment for the PAL-XFEL undulator line

    Energy Technology Data Exchange (ETDEWEB)

    Parc, Yong Woon; Hwang, Ilmoon [Pohang Accelerator Laboratory, Pohang 790-784 (Korea, Republic of); Han, Jang-Hui, E-mail: [Pohang Accelerator Laboratory, Pohang 790-784 (Korea, Republic of); Ko, In Soo [Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)


    An automated method of quadrupole beam based alignment in an X-ray free electron laser (XFEL) undulator line is proposed. To realize the automatic beam based alignment (BBA) independently of operator's skill and efforts, the procedure is simplified. Simulation results on the BBA technique using two alignment stages for the Pohang Accelerator Laboratory XFEL's (PAL-XFEL) undulator line is carried out. After a standard mechanical alignment the quadrupoles are expected to be aligned to 100 μm rms from our previous experience. A rough alignment method in this study is able to align the quadrupoles to about 40 μm rms without any pre-handling of electron beam orbit or quadrupoles position. At the second stage, the singular value decomposition (SVD) method is applied to perform a fine alignment in which the trajectory of an electron beam is controlled within 5 μm rms to the ideal orbit. All procedures are programmable to perform the BBA automatically.

  4. A tapered undulator experiment at the ELBE far infrared hybrid-resonator oscillator free electron laser. (United States)

    Asgekar, V; Lehnert, U; Michel, P


    A tapered undulator experiment was carried out at the ELBE far-infrared free electron laser (FEL). The oscillator FEL makes use of a hybrid optical resonator. The main motivation was to see whether the presence of a dispersive medium in the form of a waveguide in the resonator has any effect on the outcome. The FEL saturated power and the wavelength shifts have been measured as a function of both positive as well as negative undulator field amplitude tapering. In contrast to the typical high-gain FELs where positive tapering proves beneficial for the output power we observed an improvement of performance at negative taper. During the same experiments we studied the characteristics of the detuning curves. The width of the curves indicates a maximum small signal gain for zero taper while the output peak power increases with negative taper. The saturated power output, the detuning curve characteristics, and the wavelength shifts agrees with the theoretical predictions. Details of the experiment are presented.

  5. Auto-pickfi rst breaks with complex raypaths for undulate surface conditions

    Institute of Scientific and Technical Information of China (English)

    An Sheng-Pei; Hu Tian-Yue; Cui Yong-Fu; Duan Wen-Sheng; Peng Geng-Xin


    First-break picking is the key step in seismic data processing for surveying undulate surfaces, and directly infl uences the precision of near-surface modeling and effects of static corrections. The currentfi rst-break auto-picking methods may fail when the signal-to-noise ratio (SNR) is low for seismic data in the undulate area, and require labor and time intensive manual picking. This study develops an improved super-virtual interferometry (SVI) method that combines multichannel and multidomain quality control (MMQC) techniques to achieve auto-pickedfi rst breaks. The improved SVI method extends the SVI application to enhance the SNR for near-surface scattered waves for thefi rst time, which allows for the SVI method to adapt tofi rst breaks with complex raypaths by linear combination of refractions and near-surface scattered waves. Methods of inverse and multidomain interferometry are developed to effectively enhance the virtual records extracted by the SVI method. The deconvolution filter for waveforms is used to increase resolution and reduce false picks, while the MMQC technique is designed to auto-correct false picks and increase the stability of auto-pickingfi rst breaks. The robust technique developed in this study enables stable processing of large 3D seismic datasets. Higher quality results are obtained using the approach presented in this paper to actualfi eld data from the mountain areas in western China, when compared to some commonly used commercial software.

  6. Analysis of baroreflex sensitivity during undulation pump ventricular assist device support. (United States)

    Liu, Hongjian; Shiraishi, Yasuyuki; Zhang, Xiumin; Song, Hojin; Saijo, Yoshifumi; Baba, Atsushi; Yambe, Tomoyuki; Abe, Yusuke; Imachi, Kou


    The aim of this study was to examine the baroreflex sensitivity (BRS), which involves the autonomic nervous system, in a goat with a chronically implanted undulation pump ventricular assist device (UPVAD). The UPVAD involved transforming the rotation of a brushless DC motor into an undulating motion by a disc attached via a special linking mechanism, and a jellyfish valve in the outflow cannula to prevent diastolic backflow. The pump was implanted into the thoracic cavity of a goat by a left thoracotomy, and the inflow and outflow cannulae were sutured to the apex of the left ventricle and to the descending aorta, respectively. The driving cable was wired percutaneously to an external controller. Electrocardiogram and hemodynamic waveforms were recorded at a sampling frequency of 1 kHz. BRS was determined when awake by the slope of the linear regression of R-R interval against mean arterial pressure changes, which were induced by the administration of methoxamine hydrochloride, both with continuous driving of the UPVAD as well as without assistance. BRS values during the UPVAD support and without assistance were 1.60 +/- 0.30 msec/mm Hg and 0.98 +/- 0.22 msec/mm Hg (n = 5, P < 0.05), respectively. BRS was significantly improved during left ventricular assistance. Therefore, UPVAD support might decrease sympathetic nerve activity and increase parasympathetic nerve activity to improve both microcirculation and organ function.

  7. Contribution of collagen fiber undulation to regional biomechanical properties along porcine thoracic aorta. (United States)

    Zeinali-Davarani, Shahrokh; Wang, Yunjie; Chow, Ming-Jay; Turcotte, Raphaël; Zhang, Yanhang


    As major extracellular matrix components, elastin, and collagen play crucial roles in regulating the mechanical properties of the aortic wall and, thus, the normal cardiovascular function. The mechanical properties of aorta, known to vary with age and multitude of diseases as well as the proximity to the heart, have been attributed to the variations in the content and architecture of wall constituents. This study is focused on the role of layer-specific collagen undulation in the variation of mechanical properties along the porcine descending thoracic aorta. Planar biaxial tensile tests are performed to characterize the hyperelastic anisotropic mechanical behavior of tissues dissected from four locations along the thoracic aorta. Multiphoton microscopy is used to image the associated regional microstructure. Exponential-based and recruitment-based constitutive models are used to account for the observed mechanical behavior while considering the aortic wall as a composite of two layers with independent properties. An elevated stiffness is observed in distal regions compared to proximal regions of thoracic aorta, consistent with sharper and earlier collagen recruitment estimated for medial and adventitial layers in the models. Multiphoton images further support our prediction that higher stiffness in distal regions is associated with less undulation in collagen fibers. Recruitment-based models further reveal that regardless of the location, collagen in the media is recruited from the onset of stretching, whereas adventitial collagen starts to engage with a delay. A parameter sensitivity analysis is performed to discriminate between the models in terms of the confidence in the estimated model parameters.

  8. 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)


    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.

  9. Conceptual design of an undulator system for a dedicated bio-imaging beamline at the European X-ray FEL

    Energy Technology Data Exchange (ETDEWEB)

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


    We describe a future possible upgrade of the European XFEL consisting in the construction of an undulator beamline dedicated to life science experiments. The availability of free undulator tunnels at the European XFEL facility offers a unique opportunity to build a beamline optimized for coherent diffraction imaging of complex molecules, like proteins and other biologically interesting structures. Crucial parameters for such bio-imaging beamline are photon energy range, peak power, and pulse duration. Key component of the setup is the undulator source. The peak power is maximized in the photon energy range between 3 keV and 13 keV by the use of a very efficient combination of self-seeding, fresh bunch and tapered undulator techniques. The unique combination of ultra-high peak power of 1 TW in the entire energy range, and ultrashort pulse duration tunable from 2 fs to 10 fs, would allow for single shot coherent imaging of protein molecules with size larger than 10 nm. Also, the new beamline would enable imaging of large biological structures in the water window, between 0.3 keV and 0.4 keV. In order to make use of standardized components, at present we favor the use of SASE3-type undulator segments. The number segments, 40, is determined by the tapered length for the design output power of 1 TW. The present plan assumes the use of a nominal electron bunch with charge of 0.1 nC. Experiments will be performed without interference with the other three undulator beamlines. Therefore, the total amount of scheduled beam time per year is expected to be up to 4000 hours.

  10. Three-dimensional, time-dependent simulation of free-electron lasers with planar, helical, and elliptical undulators (United States)

    Freund, H. P.; van der Slot, P. J. M.; Grimminck, D. L. A. G.; Setija, I. D.; Falgari, P.


    Free-electron lasers (FELs) have been built ranging in wavelength from long-wavelength oscillators using partial wave guiding through ultraviolet through hard x-ray that are either seeded or start from noise. In addition, FELs that produce different polarizations of the output radiation ranging from linear through elliptic to circular polarization are currently under study. In this paper, we develop a three-dimensional, time-dependent formulation that is capable of modeling this large variety of FEL configurations including different polarizations. We employ a modal expansion for the optical field, i.e., a Gaussian expansion with variable polarization for free-space propagation. This formulation uses the full Newton–Lorentz force equations to track the particles through the optical and magnetostatic fields. As a result, arbitrary three-dimensional representations for different undulator configurations are implemented, including planar, helical, and elliptical undulators. In particular, we present an analytic model of an APPLE-II undulator to treat arbitrary elliptical polarizations, which is used to treat general elliptical polarizations. To model oscillator configurations, and allow propagation of the optical field outside the undulator and interact with optical elements, we link the FEL simulation with the optical propagation code OPC. We present simulations using the APPLE-II undulator model to produce elliptically polarized output radiation, and present a detailed comparison with recent experiments using a tapered undulator configuration at the Linac Coherent Light Source. Validation of the nonlinear formation is also shown by comparison with experimental results obtained in the Sorgente Pulsata Auto-amplificata di Radiazione Coerente SASE FEL experiment at ENEA Frascati, a seeded tapered amplifier experiment at Brookhaven National Laboratory, and the 10 kW upgrade oscillator experiment at the Thomas Jefferson National Accelerator Facility.

  11. 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


    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.

  12. 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)


    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.

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

    CERN Document Server

    Serkez, Svitozar; Saldin, Evgeni; Zagorodnov, Igor; Geloni, Gianluca


    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.

  14. A Comparative Numerical Study on the Performances and Vortical Patterns of Two Bioinspired Oscillatory Mechanisms: Undulating and Pure Heaving. (United States)

    Ebrahimi, Mohsen; Abbaspour, Madjid


    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.

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

    Directory of Open Access Journals (Sweden)

    Mohsen Ebrahimi


    Full Text Available 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.

  16. 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


    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.

  17. Conceptual design of an undulator system for a dedicated bio-imaging beamline at the European X-ray FEL

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni


    We describe a future possible upgrade of the European XFEL consisting in the construction of an undulator beamline dedicated to life science experiments. The availability of free undulator tunnels at the European XFEL facility offers a unique opportunity to build a beamline optimized for coherent diffraction imaging of complex molecules, like proteins and other biologically interesting structures. Crucial parameters for such bio-imaging beamline are photon energy range, peak power, and pulse duration. Key component of the setup is the undulator source. The peak power is maximized in the photon energy range between 3 keV and 13 keV by the use of a very efficient combination of self-seeding, fresh bunch and tapered undulator techniques. The unique combination of ultra-high peak power of 1 TW in the entire energy range, and ultrashort pulse duration tunable from 2 fs to 10 fs, would allow for single shot coherent imaging of protein molecules with size larger than 10 nm. Also, the new beamline would enable imagin...

  18. An undulation theory for condensation in open end slit pores: critical hysteresis temperature & critical hysteresis pore size. (United States)

    Fan, Chunyan; Zeng, Yonghong; Do, D D; Nicholson, D


    A new theory of condensation in an open end slit pore, based on the concept of temperature dependent undulation, at the interface separating the adsorbed phase and the gas-like region, is presented. The theory, describes, for the first time, the microscopic origin of the critical hysteresis temperature and the critical hysteresis pore size, properties which are not accessible to any classical theories.

  19. Compact X-ray free-electron laser based on an optical undulator

    Energy Technology Data Exchange (ETDEWEB)

    Bacci, A.; Maroli, C. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Petrillo, V. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Universita degli Studi di Milano, Via Celoria 16, 20133 Milan (Italy)], E-mail:; Rossi, A.R.; Serafini, L. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Tomassini, P. [Sezione di Milano INFN, Via Celoria 16, 20133 Milan (Italy); Universita degli Studi di Pisa, Via Buonarroti, 256127 Pisa (Italy)


    The interaction between a very high-brightness electron beam and a relativistically intense optical laser pulse produces X-rays via coherent Thomson back scattering with FEL collective amplification. The phenomenon is, however, very selective, so that the characteristics of both electron and laser beam must satisfy tight requirements in terms of beam current, emittance, energy spread and laser amplitude stability within the pulse. The three-dimensional equations governing the radiation phenomena have been studied in both linear and non-linear regime and solved numerically for the particularly interesting values of wavelengths of 1 A, 1 and 12 nm. The performance of the collective Thomson source has been compared with that of an equivalent static undulator. A set of scaling laws ruling the phenomenon is also presented.

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

    Directory of Open Access Journals (Sweden)

    Srikumar Panda


    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.

  1. 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


    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 ...

  2. Using superconducting undulator for enhanced imaging capabilities of MaRIE

    Energy Technology Data Exchange (ETDEWEB)

    Yampolsky, Nikolai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    MaRIE x-ray free electron laser (FEL) is envisioned to deliver a burst of closely spaced in time pulses for enabling the capability of studying the dynamic processes in a sample. MaRIE capability can be largely enhanced using the superconducting undulator, which has the capability of doubling its period. This technology will allow reaching the photon energy as low as ~200-500 eV. As a result, the MaRIE facility will have a broader photon energy range enabling a larger variety of experiments. The soft x-ray capability is more likely to achieve the 3D imaging of dynamic processes in noncrystal materials than the hard x-ray capability alone.

  3. Numeric Simulation on the Performance of an Undulating Fin in the Wake of a Periodic Oscillating Plate

    Directory of Open Access Journals (Sweden)

    Zhang Yong-Hua


    Full Text Available A two-dimensional unsteady computational fluid dynamics (CFD method using an unstructured, grid-based and unsteady Navier-Stokes solver with automatic adaptive re-meshing to compute the unsteady flow was adopted to study the hydrodynamic interaction between a periodic oscillating plate and a rigid undulating fin in tandem arrangement. The user-defined function (UDF program was compiled to define the undulating and oscillating motion. First, the influence of the distance between the anterior oscillating plate and the posterior undulating fin on the non-dimensional drag coefficient of the fin was investigated. Ten different distances, D=0.2L, 0.4L, 0.6L, 0.8L, 1.0L, 1.2L, 1.4L, 1.6L, 1.8L and 2.0L, were considered. The performance of the fin for different distances (D is different. Second, the plate oscillating angle (5.7o, 10 o, 20 o, 30 o, 40 o, 45 o, 50 o and frequency (0.5 Hz, 1.0 Hz, 1.5 Hz, 2.0 Hz, 2.5 Hz, 3.0 Hz, 3.5 Hz, 4.0 Hz effects on the non-dimensional drag coefficient of the fin were also implemented. The pressure distribution on the fin was computed and integrated to provide fin forces, which were decomposed into lift and thrust. Meanwhile, the flow field was demonstrated and analysed. Based on the flow structures, the reasons for different undulating performances were discussed. It shows that the results largely depend on the distance between the two objects. The plate oscillating angle and frequency also make a certain contribution to the performance of the posterior undulating fin. The results are similar to the interaction between two undulating objects in tandem arrangement and they may provide a physical insight into the understanding of fin interaction in fishes or bio-robotic underwater propulsors that are propelled by multi fins.

  4. 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)


    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.

  5. Three-Dimensional, Time-Dependent Simulation of Free-Electron Lasers with Planar, Helical, and Elliptical Undulators

    CERN Document Server

    Freund, H P; Grimminck, D L A G; Setija, I D; Falgari, P


    Free-electron lasers (FELs) have been built ranging in wavelength from long-wavelength oscillators using partial wave guiding through ultraviolet through hard x-ray that are either seeded or start from noise (SASE). In addition, FELs that produce different polarizations of the output radiation ranging from linear through elliptic to circular polarization are currently under study. In this paper, we develop a three-dimensional, time-dependent formulation that is capable of modeling this large variety of FEL configurations including different polarizations. We employ a modal expansion for the optical field, i.e., a Gaussian expansion with variable polarization for free-space propagation. This formulation uses the full Newton-Lorentz force equations to track the particles through the optical and magnetostatic fields. As a result, arbitrary three-dimensional representations for different undulator configurations are implemented, including planar, helical, and elliptical undulators. In particular, we present an an...

  6. 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


    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.

  7. Surface-micromachined magnetic undulator with period length between 10μm and 1 mm for advanced light sources (United States)

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


    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.

  8. How kilometric sandy shoreline undulations correlate with wave and morphology characteristics: preliminary analysis on the Atlantic coast of Africa (United States)

    Idier, D.; Falqués, A.


    Sandy coasts are characterized by a number of rhythmic patterns like, amongst others, shoreline undulations or sandwaves at a kilometric scale. One hypothesis for their formation is that high angle waves (large incidence angle with respect to shore normal) could induce an instability of the shoreline (Ashton et al., 2001). More recently, a scaling for their wavelength has also been proposed (van den Berg et al., 2014). The existing studies rely mainly on modelling but quantitative field tests are lacking. We aim at investigating how both the formation hypothesis of these shoreline undulations and the theoretical scaling do fit with nature at a global scale. The first step, which is the goal of this paper, is to set up the methodology by analyzing the Atlantic African coast as test site. First, based on global databases, shoreline wavelength LS, wave characteristics (obliquity θW and wavelength λW) and mean shoreface slope β are determined. Then the wave obliquity is confronted with the presence of shoreline undulations. Finally the values of the ratio β LS / λW are estimated and discussed in comparison with the estimate of van den Berg et al. (2014). It is found that the correlation between shoreline sandwave occurrence and wave obliquity is very good, allowing the identification of 5 new potential unstable shoreline stretches, whereas the results on the scaling are not conclusive and deserve further investigations.

  9. Fiber diffraction using the BioCAT undulator beamline at the Advanced Photon Source (United States)

    Irving, T. C.; Fischetti, R.; Rosenbaum, G.; Bunker, G. B.; Biophysics Collaborative Access Team (BioCAT)


    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 40×200 μm (FWHM) has been observed which contained essentially all of the 1.5-2.5×10 13 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 scanner and a 1 k×1 k CCD detector optimized for small-angle applications. Future developments will include, in vacuum beam monitoring, longer camera lengths (6-8 m), and optimizations to improve first-order resolution in small-angle applications.

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

    CERN Document Server

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


    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...

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

    CERN Document Server

    Yoshida, Hiroaki; Washizu, Hitoshi


    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...

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

    CERN Document Server

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


    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.

  13. Developments in Polarization and Energy Control of APPLE-II Undulators at Diamond Light Source (United States)

    Longhi, E. C.; Bencok, P.; Dobrynin, A.; Rial, E. C. M.; Rose, A.; Steadman, P.; Thompson, C.; Thomson, A.; Wang, H.


    A pair of 2m long APPLE-II type undulators have been built for the I10 BLADE beamline at Diamond Light Source. These 48mm period devices have gap as well as four moveable phase axes which provide the possibility to produce the full range of elliptical polarizations as well as linear polarization tilted through a full 180deg. The mechanical layout chosen has a 'master and slave' arrangement of the phase axes on the top and bottom. This arrangement allows the use of symmetries to provide operational ease for both changing energy using only the master phase while keeping fixed linear horizontal or circular polarization, as well as changing linear polarization angle while keeping fixed energy [1]. The design allows very fast motion of the master phase arrays, without sacrifice of accuracy, allowing the possibility of mechanical polarization switching at 1Hz for dichroism experiments. We present the mechanical design features of these devices, as well as the results of magnetic measurements and shimming from before installation. Finally, we present the results of characterization of these devices by the beamline, including polarimetry, which has been done on the various modes of motion to control energy and polarization. These modes of operation have been available to users since 2011.

  14. Characterization of Oxidized Ferritic Stainless Steel with Undulated Surfaces for Metallic Interconnects

    Directory of Open Access Journals (Sweden)

    Daniel R. MUMM


    Full Text Available One of the candidates for metallic interconnects of solid oxide fuel cells is a ferritic stainless steel, Crofer22 APU. Ferritic stainless steel Crofer22 APU samples with different roughness were prepared by grinding with SiC grinding papers of various grits, and a polished Crofer22 APU sample was also prepared. The prepared samples were then thermally cycled. The variations of their oxidation behavior with surface roughness and the number of thermal cycles were investigated. After 120 thermal cycles (a total 3000 h of exposure at 800 °C, the polished Crofer22 APU had arelatively flat, continuous Cr2O3 layer (thickness, ~ 1 μm, while the Crofer22 APU ground with 80 grit showed an undulating, continuous Cr2O3 layer (thickness, ~ 2 μm. For the samples that were thermally cycled 4 times (at 800 °C for 100 h total, the area specific resistance (ASR increased as grit number increased for all measured temperatures (600 – 850 °C. Generally, for the samples that were thermally cycled 20 times, the ASR decreased slowly as the grit number increased. For the samples thermally cycled 40 times, the ASR decreased in general at all the measuring temperatures as the number of grit increased, indicating that the polished Crofer22 APU is better than those with rougher surfaces for the application of Crofer22 APU to an interconnect of SOFC. 

  15. Neuromuscular Responses to 14 Weeks of Traditional and Daily Undulating Resistance Training. (United States)

    Ullrich, B; Holzinger, S; Soleimani, M; Pelzer, T; Stening, J; Pfeiffer, M


    This study compared traditional (TP) and daily undulating (DUP) periodization on muscle strength, EMG-estimated neural drive and muscle architecture of the quadriceps femoris (QF). 10 non-athletic females (24.4±3.2 years) performed 14 weeks of isometric training for the QF exercising 1 leg using TP and the contralateral leg using DUP. Intensities varied from 60% to 80% of MVC and the intensity zones and training volume were equated for each leg. Knee extension MVC, maximal voluntary QF-EMG activity and vastus lateralis (VL) muscle architecture were measured in both legs before, after 6 weeks and after 14 weeks of training using dynamometry, surface EMG and ultrasonography. Isometric MVC and maximal QF-EMG remained unaltered after 6 weeks of training, but were significantly (PMVC: TP 24%, DUP 23%; QF-EMG: TP 45%, DUP 46%). VL-architecture remained unchanged following 6 weeks of training, but VL-muscle thickness (TP 17%, DUP 16%) and fascicle length (TP 16%, DUP 17%) displayed significant (P<0.05) enlargements after 14 weeks in both legs. Importantly, these temporal neuromuscular alterations displayed no significant differences between the training legs. Therefore, periodization may not act as a key trigger for neuromuscular adaptations.

  16. Numerical estimation of heat distribution from the implantable battery system of an undulation pump LVAD. (United States)

    Okamoto, Eiji; Makino, Tsutomu; Nakamura, Masatoshi; Tanaka, Shuji; Chinzei, Tsuneo; Abe, Yusuke; Isoyama, Takashi; Saito, Itsuro; Mochizuki, Shu-ichi; Imachi, Kou; Inoue, Yusuke; Mitamura, Yoshinori


    We have been developing an implantable battery system using three series-connected lithium ion batteries having an energy capacity of 1,800 mAh to drive an undulation pump left ventricular assist device. However, the lithium ion battery undergoes an exothermic reaction during the discharge phase, and the temperature rise of the lithium ion battery is a critical issue for implantation usage. Heat generation in the lithium ion battery depends on the intensity of the discharge current, and we obtained a relationship between the heat flow from the lithium ion battery q(c)(I) and the intensity of the discharge current I as q(c)(I) = 0.63 x I (W) in in vitro experiments. The temperature distribution of the implantable battery system was estimated by means of three-dimentional finite-element method (FEM) heat transfer analysis using the heat flow function q(c)(I), and we also measured the temperature rise of the implantable battery system in in vitro experiments to conduct verification of the estimation. The maximum temperatures of the lithium ion battery and the implantable battery case were measured as 52.2 degrees C and 41.1 degrees C, respectively. The estimated result of temperature distribution of the implantable battery system agreed well with the measured results using thermography. In conclusion, FEM heat transfer analysis is promising as a tool to estimate the temperature of the implantable lithium ion battery system under any pump current without the need for animal experiments, and it is a convenient tool for optimization of heat transfer characteristics of the implantable battery system.

  17. 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))


    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.

  18. Predicting path from undulations for C. elegans using linear and nonlinear resistive force theory (United States)

    Keaveny, Eric E.; Brown, André E. X.


    A basic issue in the physics of behaviour is the mechanical relationship between an animal and its surroundings. The model nematode C. elegans provides an excellent platform to explore this relationship due to its anatomical simplicity. Nonetheless, the physics of nematode crawling, in which the worm undulates its body to move on a wet surface, is not completely understood and the mathematical models often used to describe this phenomenon are empirical. We confirm that linear resistive force theory, one such empirical model, is effective at predicting a worm’s path from its sequence of body postures for forward crawling, reversing, and turning and for a broad range of different behavioural phenotypes observed in mutant worms. Worms recently isolated from the wild have a higher effective drag anisotropy than the laboratory-adapted strain N2 and most mutant strains. This means the wild isolates crawl with less surface slip, perhaps reflecting more efficient gaits. The drag anisotropies required to fit the observed locomotion data (70  ±  28 for the wild isolates) are significantly larger than the values measured by directly dragging worms along agar surfaces (3–10 in Rabets et al (2014 Biophys. J. 107 1980–7)). A proposed nonlinear extension of the resistive force theory model also provides accurate predictions, but does not resolve the discrepancy between the parameters required to achieve good path prediction and the experimentally measured parameters. We confirm that linear resistive force theory provides a good effective model of worm crawling that can be used in applications such as whole-animal simulations and advanced tracking algorithms, but that the nature of the physical interaction between worms and their most commonly studied laboratory substrate remains unresolved.

  19. 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


    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.

  20. 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


    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.

  1. 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 (United States)

    Kulipanov, Gennadii N.


    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.

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

    CERN Document Server

    Reiche, Sven; Emma, Paul; Fawley, William M; Huang, Zhirong; Nuhn, Heinz-Dieter; Stupakov, Gennady


    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 ...

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

    CERN Document Server

    Geloni, Gianluca; Saldin, Evgeni


    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 (United States)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni


    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


    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. Cryogenic Field Measurement of Pr2Fe14B Undulator and Performance Enhancement Options at the NSLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T.; Chubar, O.; Harder, David A.; Lehecka, Michael; Rank, James; Rakowsky, George; Spataro, Charles


    Short period (14.5mm) hybrid undulator arrays composed of Praseodymium Iron Boron (Pr{sub 2}Fe{sub 14}B) magnets (CR53, NEOMAX, Inc.) and vanadium permendur poles have been fabricated at Brookhaven National Laboratory. Unlike Neodymium Iron Boron (Nd{sub 2}Fe{sub 14}B) magnets which exhibit spin reorientation at temperatures below 150K, PrFeB arrays monotonically increase performance with lower operating temperature. It opens up the posibility for use in operating a cryo-permanent magnet undulator (CPMU) in the range of 40K to 60K where very efficient cryocoolers are available. Magnetic flux density profiles were measured at various temperature ranges from room temperature down to liquid helium (LHe) using the Vertical Testing Facility (VTF) at the National Snchrotron Light Source-II (NSLS-II). Temperature variations of phase error have been characterized. In addition, we examined the use of textured Dysprosium (Dy) poles to replace permendur poles to obtain further improvement in performance.

  7. Excel Center

    Institute of Scientific and Technical Information of China (English)


    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.

  8. The Continuous Plankton Recorder: concepts and history, from Plankton Indicator to undulating recorders [review article (United States)

    Reid, P. C.; Colebrook, J. M.; Matthews, J. B. L.; Aiken, J.; Continuous Plankton Recorder Team


    Alister Hardy conceived the Continuous Plankton Recorder (CPR) survey in the 1920s as a means of mapping near-surface plankton in space and time, interpreting the changing fortunes of the fisheries and relating plankton changes to hydrometeorology and climatic change. The seed he planted has grown to become the most extensive long-term survey of marine organisms in the world and the breadth of his vision becomes ever more apparent. The survey has now run for over 70 years and its value increases with every passing decade. Operating from ‘ships of opportunity’ the machines used are robust, reliable and easy to handle. Wherever possible, all the sampling and analytical methods have not been changed to maintain the consistency of the time series. Computerisation and the development of new statistical approaches have increased our ability to handle the large quantities of information generated and enhance the sensitivity of the data analyses. This overview, based on almost 900 papers, recounts the various phases in the history of the survey. It starts with the Indicator Survey (1921-1934), the deployment of the first CPR on the Discovery Expedition (1924-1927) and the early CPR survey in the North Sea (1931-1939). The survey reopened in 1946 after the Second World War and expanded across the North Atlantic to North America from 1959. Taxonomic studies were initiated and an emphasis was placed on patterns of distribution, which were seen to reflect the varying oceanographic conditions. The years 1968-1976 saw further expansion with operations even in the American Great Lakes, publication of a Plankton Atlas and initial evidence for a downward trend in plankton biomass. At about this time electronic instrumentation was attached to CPRs to make additional measurements and work was started on the development of a new generation of undulating Continuous Plankton and Environmental Recorders (CPERs). In 1976 the survey moved to Plymouth. Scientific priorities in the UK

  9. Fabrication and Test of a Nb3Sn Model Magnet With Ceramic Insulation for the Next Generation Undulator of the LHC

    CERN Document Server

    Elias, N; Dalexandro, N; Giloux, C; Bordini, B; Maccaferri, R


    The future run of the Large Hadron Collider with lead ions will require important modifications in the synchrotron radiation profile monitor system, which at present comprises two superconducting undulators wound from Nb-Ti conductor, delivering 5 T in a 60 mm gap, and with a period of 280 mm. Whilst the gap and the nominal field of the future undulators will remain the same, the period shall be 140 mm, which translates to a peak field of over 8 T in the coils and hence requires the use of Nb3Sn technology. In this paper the electromagnetic design of the undulator is summarized. We describe the fabrication of a race-track coil wound with a 0.8 mm diameter Nb3Sn strand with ceramic insulation. Finally, the results of successful tests made at 4.3 K and 1.9 K in a mirror configuration are presented. 10 T at 4.3 K and 11.5 T at 1.9 K were measured in the yoke gap, thus validating this concept for the future undulator.

  10. 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)


    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.

  11. 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


    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.

  12. X-ray absorption spectroscopy of diluted system by undulator photon source and multi-element solid-state detector

    CERN Document Server

    Tanida, H


    In order to measure the extended X-ray absorption fine structure (EXAFS) spectrum of an ultra-diluted system, an optics and detector control system for a synchrotron radiation beamline is developed. The undulator gap width is continuously tuned to obtain the maximum X-ray photon flux during the energy scan for the EXAFS measurement. A piezoelectric translator optimizes the parallelism of the double crystal in a monochromator at each measurement point to compensate for mechanical errors of the monochromator, resulting in a smooth and intense X-ray photon flux during the measurement. For a detection of a weak fluorescence signal from diluted samples, a 19-element solid-state detector and digital signal processor are used. A K-edge EXAFS spectrum of iron in a myoglobin aqueous solution with a concentration of 5.58 parts per million was obtained by this system.

  13. Generating quasi-single-cycle THz pulse from frequency-chirped electron bunch train and a tapered undulator

    Institute of Scientific and Technical Information of China (English)

    Zhuoran Ma; Zhe Wang; Feichao Fu; Rui Wang; Dao Xiang


    We propose a proof-of-principle experiment to test a new scheme to produce a single-cycle radiation pulse in free-electron lasers(FELs). Here, a few α-BBO crystals will be first used to produce an equally spaced laser pulse train.Then, the laser pulse train illuminates the cathode to produce a frequency-chirped electron bunch train in a photocathode rf gun. Finally, the frequency-chirped electron bunch train passes through a tapered undulator to produce a quasi-single-cycle THz pulse. This experiment should allow comparison and confirmation of predictive models and scaling laws, and the preliminary experimental results will also be discussed.

  14. 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


    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%.

  15. Distribution center

    Institute of Scientific and Technical Information of China (English)


    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. Erosão real e estimada através da RUSLE em estradas florestais, em relevo ondulado a fortemente ondulado Real and estimative erosion through RUSLE from forest roads in undulated at heavily undulated relief

    Directory of Open Access Journals (Sweden)

    Carla Maria Camargo Correa


    Full Text Available O objetivo deste trabalho foi avaliar as perdas de solo provenientes de trechos de estradas de uso florestal inseridas na região de Itaiópolis, Santa Catarina, que apresenta relevo ondulado a fortemente ondulado em dois tipos de solo: Cambissolo Húmico Distrófico típico e Argissolo Vermelho-Amarelo Distrófico típico. A erosividade da chuva foi calculada através de pluviogramas e de dados de pluviosidade da empresa Rigesa - Soluções em Embalagens MeadWestvaco; a erosividade do solo foi calculada em função dos resultados de análises, a declividade e comprimento de rampa foram medidos em campo e os fatores C e P, estipulados através da literatura. A hipótese de similaridade entre os valores reais monitorados pelo período de um ano e os valores estimados pela RUSLE foi evidenciada através de análise estatística, que apresentou alta correlação nos tratamentos avaliados e se manteve dentro do limite crítico proposto pela análise, validando, portanto, essa hipótese.The objective of this work was to evaluate the soil losses from a portion of forest roads located in a region with undulated to heavily undulated relief in two types of soil: Humic Cambissoil, typical Dystrophic and Red-Yellow Argissoil, typical Dystrophic. The rainfall erosivity was calculated using rainfall data through the Rigesa Company, the soil erodibility was calculated based on the results of the analyses, the declivity and the slope length were measured in the field, and Factors C and P were estimated from literature. The similarity hypothesis between the real values monitored over a one year period and the estimated values using the RUSLE were evidenced via statistical analyses that presented high correlations in the evaluated treatments, remaining inside the critical limit considered for the analyses, therefore validating the hypothesis.

  17. Neuromuscular Responses to Short-Term Resistance Training With Traditional and Daily Undulating Periodization in Adolescent Elite Judoka. (United States)

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


    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.

  18. 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


    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...

  19. 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: [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)


    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)

  20. 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


    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.

  1. 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


    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.

  2. 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


    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.)

  3. The effect of traveling wave shapes in the maneuver control and efficiency of an underwater robot propelled by an undulating fin (United States)

    Liu, Hanlin; Curet, Oscar


    Effective control of propulsive undulating fins has the potential to enhance the maneuverability and efficiency of underwater vehicles allowing them to navigate in more complex environments. Aquatic animals using this type of propulsion are able to perform complex maneuvers by sending different traveling waves along one or multiple elongated fins. Recent work has investigated the propulsive forces, the hydrodynamics and the efficiency of an undulating ribbon fin. However, it is still not understood how different traveling wave shapes along the fin can be used to control the hydrodynamic forces and torques to perform different maneuvers. In this work, we study the effect of traveling wave shapes on the hydrodynamic forces and torques, swimming speed, maneuver control and propulsive performance of an underwater vehicle propelled by an undulating fin. The underwater robot propels by actuating a fin that is composed of sixteen independent rays interconnected with a flexible membrane. The hull contains all the electronics, batteries, motors and sensors. The underwater vehicle was tested in a water tank-flume facility. In a series of experiments, we measured the motion of the vessel and the power consumption for different traveling wave patterns. In addition, we measured the flow around the fin using Particle Image Velocimetry. We present the results concerning the power distribution along the fin, propulsive efficiency, free-swimming speed and pitch control based on different fin kinematics. National Science Foundation under Grant No. 1420774.

  4. The formation mechanism and impact of streamwise vortices on NACA 0021 airfoil's performance with undulating leading edge modification (United States)

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


    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.

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

    CERN Document Server

    Fawley, W M; Emma, P; Huang, Z; Nuhn, H D; Reiche, S; Stupakov, G


    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 component is the most critical and depends upon the chamber wall material (e.g. Cu) and its radius. Of recent interest [1] is the so-called "AC" component of the resistive wake which can lead to strong variations on very short timescales (e.g. ~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 a...

  6. A high resolution pulsed field ionization photoelectron study of O{sub 2} using third generation undulator synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, C.; Heimann, P. [Chemical Sciences Division and Advanced Light Source, Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Evans, M.; Stimson, S.; Fenn, P.T.; Ng, C.Y. [Ames Laboratory, United States Department of Energy]|[Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)


    We have improved a newly developed experimental scheme for high resolution pulsed field ionization photoelectron (PFI-PE) studies [Hsu {ital et al.}, Rev. Sci. Instrum. (in press)] using the high resolution monochromatized multibunch undulator synchrotron source of the Chemical Dynamics Beamline at the Advanced Light Source. This improved scheme makes possible PFI-PE measurements with essentially no contamination by background electrons arising from direct photoionization and prompt autoionization processes. We present here a preliminary analysis of the rotationally resolved PFI-PE spectrum for O{sub 2} obtained at a resolution of 0.5 meV (full-width-at-half-maximum) in the photon energy range of 18.1{endash}19.4 eV, yielding accurate ionization energies for the transitions O{sub 2}{sup +}(b{sup 4}{Sigma}{sub g}{sup {minus}}, v{sup +}=0{endash}9, N{sup +}=1){l_arrow}O{sub 2}(X{sup 3}{Sigma}{sub g}{sup {minus}}, v=0, N=1). {copyright} {ital 1997 American Institute of Physics.}

  7. 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


    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...

  8. 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 (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

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


    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.

  10. Centering research

    DEFF Research Database (Denmark)

    Katan, Lina Hauge; Baarts, Charlotte

    and collected 24 portfolios in which students reflect auto-ethnographically on their educational practices. Analyzing this qualitative material, we explore how researchers and students respectively read and write to develop and advance their thinking in those learning processes that the two groups fundamentally...... share as the common aim of both research and education. Despite some similarities, we find that how the two groups engage in and benefit from reading and writing diverges significantly. Thus we have even more reason to believe that centering practice-based teaching on these aspects of research is a good...

  11. 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


    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

  12. 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


    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.

  13. 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)


    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.

  14. Performance of the undulator based ultraviolet and soft x-ray beamline for catalysis and surface science at National Synchrotron Radiation Laboratory (United States)

    Du, Liangliang; Du, Xuewei; Wei, Shen; Li, Chaoyang; Pan, Congyuan; Ju, Huanxin; Wang, Qiuping; Zhu, Junfa


    The undulator based ultraviolet and soft x-ray beamline BL11U for catalysis and surface science at National Synchrotron Radiation Laboratory (NSRL) has been under opteration for months and the present performance is described. This beamline utilizes radiation from an in-vacuum undulator, which has 30 magnetic periods with the period length of 40 mm. A varied-line-spacing plane grating monochromator is employed tto cover the photon energy region of 20-600 eV by two gratings with nominal groove densities of 400 llmm and 1200 l/mm respectively. The energy resolution power E/ΔE is measured with a gas ionization chamber and the photon flux is measured by a photodiode. Results show that the resolution power is better than 10,000 at a photon energy of 29.2 eV. And the flux is higher than 1×1010 phs/s under 300 mA ring beam current for most of the covered photon energy.

  15. Mississippi Technology Transfer Center (United States)


    The Mississippi Technology Transfer Center at the John C. Stennis Space Center in Hancock County, Miss., was officially dedicated in 1987. The center is home to several state agencies as well as the Center For Higher Learning.

  16. 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


    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.

  17. Investigating excitation-dependent and fringe-field effects of electromagnet and permanent-magnet phase shifters for a crossed undulator (United States)

    Chung, Ting-Yi; Yang, Chih-Sheng; Chu, Yun-Liang; Lin, Fu-Yuan; Jan, Jyh-Chyuan; Hwang, Ching-Shiang


    To enhance the flux density or to control polarization, a phase shifter was designed and used to modulate the phase matching between segmented undulators. A larger hysteresis loop causes, however, a repeatability issue in the phase matching; the fringe field of the phase shifter creates an extra magnetic-field error. The design of the phase shifter must therefore minimize the hysteresis loop and fringe field to maintain the phases exact and to ignore the crosstalk effect. Two critical issues are the hysteresis-loop problem and the fringe-field effect, which determine the radiation performance and the stability of the ring. To investigate these issues, a phase shifter was constructed to operate in accordance with electromagnetic- and permanent-type magnets; the results from the field measurements and shims are discussed here. The shimming algorithm and a compact permanent-magnet phase shifter that eliminates the issues are also presented.

  18. Transplant Center Search Form (United States)

    ... Share Your Story Give Us Feedback - A + A Transplant Center Search Form Welcome to the Blood & Marrow ... transplant centers for patients with a particular disease. Transplant Center login Username: * Password: * Request new password Join ...

  19. Children's cancer centers (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 ...

  20. Southern California Particle Center (United States)

    Federal Laboratory Consortium — At the Southern California Particle Center, center researchers will investigate the underlying mechanisms that produce the health effects associated with exposure to...

  1. Womens Business Center (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...

  2. Student Success Center Toolkit (United States)

    Jobs For the Future, 2014


    "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…

  3. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)



    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  4. 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) (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...

  5. 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) (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...

  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) (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. 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) (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...

  8. Hydrologic Engineering Center (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...

  9. NIH Clinical Centers (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,...

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    ... Aid & Attendance & Housebound Caregivers Community Living Centers (CLC) Community Nursing Homes Domiciliaries (Please contact your local VA Medical Center) Homemaker & Home Health Aid Care Hospice and Palliative Care State Veterans ...

  11. BKG Data Center (United States)

    Thorandt, Volkmar; Wojdziak, Reiner


    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.

  12. Day Care Centers (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...

  13. Poison Control Centers (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, ...

  14. Center of Attention. (United States)

    Coffey, J. Steven; Wood-Steed, Ruth


    Illustrates how college and university student centers are becoming the institution's marketing tools. Explores how the Millennium Center at the University of Missouri in St. Louis exemplifies this new trend. (GR)

  15. RSW Cell Centered Grids (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 tet....


    Federal Laboratory Consortium — The Maryland Robotics Center is an interdisciplinary research center housed in the Institute for Systems Research (link is external)within the A. James Clark School...

  17. National Rehabilitation Information Center (United States)

    ... including News and Notes) Welcome to the National Rehabilitation Information Center! We are conducting improvements to the ... experience. We apologize for any inconvenience The National Rehabilitation Information Center ( NARIC ) is the library of the ...


    Federal Laboratory Consortium — The Maryland Robotics Center is an interdisciplinary research center housed in the Institute for Systems Research (link is external) within the A. James Clark School...

  19. Automating the Media Center. (United States)

    Holloway, Mary A.


    Discusses the need to develop more efficient information retrieval skills by the use of new technology. Lists four stages used in automating the media center. Describes North Carolina's pilot programs. Proposes benefits and looks at the media center's future. (MVL)

  20. Center for Functional Nanomaterials (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...

  1. Characteristics of a miniature parallel-plate free-air ionization chamber for measuring the intensity of synchrotron radiation from an undulator (United States)

    Nariyama, Nobuteru


    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.

  2. 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)


    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.

  3. Numerical Study of Winter Diurnal Convection Over the City of Krasnoyarsk: Effects of Non-freezing River, Undulating Fog and Steam Devils (United States)

    Hrebtov, M.; Hanjalić, K.


    We performed a numerical simulation of penetrative convection of an inversion-topped weakly stratified atmospheric boundary layer over urban terrain with a strong localized source of heat and moisture. With some simplifications, the case mimics the real environment of the Krasnoyarsk region in Russia where the non-freezing river Yenisei acts as a thermal and humidity source during winter, generating an undulating fog pattern along the river accompanied with scattered `steam devils'. An idealized full diurnal cycle was simulated using an unsteady Reynolds-averaged Navier-Stokes (RANS) three-equation algebraic flux model and the novel buoyancy-accounting functions for treating the ground boundary conditions. The results show a significant effect of the river on the net temperature and moisture distribution. The localized heat and moisture source leads to strong horizontal convection and marked non-uniformity of humidity concentration in the air. An interplay of several distinct large-scale vortex systems leads to a wavy pattern of moisture plumes over the river. The simulations deal with rare natural phenomena and show the capability of the RANS turbulence closure to capture the main features of flow and scalar fields on an affordable, relatively coarse, computational grid.

  4. Exposing the Data Center


    Sergejev, Ivan


    Given the rapid growth in the importance of the Internet, data centers - the buildings that store information on the web - are quickly becoming the most critical infrastructural objects in the world. However, so far they have received very little, if any, architectural attention. This thesis proclaims data centers to be the 'churches' of the digital society and proposes a new type of a publicly accessible data center. The thesis starts with a brief overview of the history of data centers ...

  5. Data center cooling method

    Energy Technology Data Exchange (ETDEWEB)

    Chainer, Timothy J.; Dang, Hien P.; Parida, Pritish R.; Schultz, Mark D.; Sharma, Arun


    A method aspect for removing heat from a data center may use liquid coolant cooled without vapor compression refrigeration on a liquid cooled information technology equipment rack. The method may also include regulating liquid coolant flow to the data center through a range of liquid coolant flow values with a controller-apparatus based upon information technology equipment temperature threshold of the data center.

  6. 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


    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

  7. Analysis of heat generation of lithium ion rechargeable batteries used in implantable battery systems for driving undulation pump ventricular assist device. (United States)

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


    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.

  8. Test Control Center exhibit (United States)


    Have you ever wondered how the engineers at John C. Stennis Space Center in Hancock County, Miss., test fire a Space Shuttle Main Engine? The Test Control Center exhibit at StenniSphere can answer your questions by simulating the test firing of a Space Shuttle Main Engine. A recreation of one of NASA's test control centers, the exhibit explains and portrays the 'shake, rattle and roar' that happens during a real test firing.

  9. Relativistic Guiding Center Equations

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  10. Great Lakes Science Center (United States)

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  11. Small Business Development Center (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...

  12. Advanced Simulation Center (United States)

    Federal Laboratory Consortium — The Advanced Simulation Center consists of 10 individual facilities which provide missile and submunition hardware-in-the-loop simulation capabilities. The following...

  13. Environmental Modeling Center (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...

  14. Surgery center joint ventures. (United States)

    Zasa, R J


    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. Test Control Center (TCC) (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...

  16. Data Center at NICT (United States)

    Ichikawa, Ryuichi; Sekido, Mamoru


    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.

  17. Chemical Security Analysis Center (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...

  18. Airline Operation Center Workstation (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. Center for Deployment Psychology (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...

  20. Electron Microscopy Center (EMC) (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...

  1. Audio Visual Center (United States)

    Federal Laboratory Consortium — The Audiovisual Services Center provides still photographic documentation with laboratory support, video documentation, video editing, video duplication, photo/video...

  2. Funding Opportunity: Genomic Data Centers (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,

  3. Information Centers at NAL. (United States)

    Frank, Robyn C.


    Descriptions of the 12 specialized information centers of the National Agricultural Library (NAL) include subject coverage, information services provided, information technologies used, and staffing. The development of the Rural Information Center, a joint venture between the Extension Service and NAL to provide information services to local…

  4. Assessing the Assessment Center. (United States)

    LaRue, James


    Describes the historical use of assessment centers as staff development and promotional tools and their current use in personnel selection. The elements that constitute a true assessment center are outlined, and a discussion of the advantages and disadvantages for employers and applicants focuses on positions in library administration. (10…

  5. Handbook for Learning Centers. (United States)

    Norwalk Board of Education, CT.

    The handbook for learning centers contains guidelines, forms, and supplementary information to be used with all children identified as having a learning disability, mild retardation, or sensory deprivation in the Norwalk, Connecticut public schools. It is stressed that the learning center should provide supportive services for at least 35 minutes…

  6. Relative Lyapunov Center Bifurcations

    DEFF Research Database (Denmark)

    Wulff, Claudia; Schilder, Frank


    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....

  7. Energy efficient data centers

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  8. National Automotive Center - NAC (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...

  9. Test Control Center (United States)


    At the test observation periscope in the Test Control Center exhibit in StenniSphere at the John C. Stennis Space Center in Hancock County, Miss., visitors can observe a test of a Space Shuttle Main Engine exactly as test engineers might see it during a real engine test. The Test Control Center exhibit exactly simulates not only the test control environment, but also the procedure of testing a rocket engine. Designed to entertain while educating, StenniSphere includes informative dispays and exhibits from NASA's lead center for rocket propulsion and remote sensing applications. StenniSphere is open free of charge from 9 a.m. to 5 p.m. daily.

  10. Cooperative Tagging Center (CTC) (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...

  11. NMA Analysis Center (United States)

    Kierulf, Halfdan Pascal; Andersen, Per Helge


    The Norwegian Mapping Authority (NMA) has during the last few years had a close cooperation with Norwegian Defence Research Establishment (FFI) in the analysis of space geodetic data using the GEOSAT software. In 2012 NMA has taken over the full responsibility for the GEOSAT software. This implies that FFI stopped being an IVS Associate Analysis Center in 2012. NMA has been an IVS Associate Analysis Center since 28 October 2010. NMA's contributions to the IVS as an Analysis Centers focus primarily on routine production of session-by-session unconstrained and consistent normal equations by GEOSAT as input to the IVS combined solution. After the recent improvements, we expect that VLBI results produced with GEOSAT will be consistent with results from the other VLBI Analysis Centers to a satisfactory level.

  12. Center for Contaminated Sediments (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...

  13. Reliability Centered Maintenance - Methodologies (United States)

    Kammerer, Catherine C.


    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.

  14. The ORFEUS Data Center

    Directory of Open Access Journals (Sweden)

    B. Dost


    Full Text Available 1993 the ORFEUS Data Center (ODC; Dost, 1991 changed hosting organisation. It moved within the Netherlands from the University of Utrecht to the Royal Netherlands Meteorological Institute (KNM1 in de Bilt. This change in hosting organisation was necessary to ensure a longer term stability in the operation of the ODC. Key issues for the ODC are the rapid on-line data access and quality controlled, complete and efficient off-line data access. During 1992 the ODC became the European node in the international SPYDER system which provides near real-time access to digital broadband data from selected high quality stations. Electronic messages trigger soveral centers well distributed over the globe. These centers then collect the data by modem from selected stations in their region. Finally, data are distributed between data centers over internet.

  15. Advanced data center economy


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


    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.

  16. Center Innovation Fund Program (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...

  17. Global Hydrology Research Center (United States)

    National Aeronautics and Space Administration — The GHRC is the data management and user services arm of the Global Hydrology and Climate Center. It encompasses the data and information management, supporting...

  18. National Farm Medicine Center (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 ...

  19. Hazardous Waste Research Center (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...

  20. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Community Outreach Resource Center Toy Recall Statistics CO Poster Contest Pool Safely Business & Manufacturing Business & Manufacturing Business ... Featured Resources CPSC announces winners of carbon monoxide poster contest Video View the blog Clues You Can ...

  1. World Trade Center

    Index Scriptorium Estoniae


    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

  2. Health Center Controlled Network (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...

  3. USU Patient Simulation Center (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.,...

  4. HUD Homeownership Centers (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 Homeownership...

  5. Mental Health Screening Center (United States)

    ... Releases & Announcements Public Service Announcements Partnering with DBSA Mental Health Screening Center These online screening tools are not ... you have any concerns, see your doctor or mental health professional. Depression This screening form was developed from ...

  6. FEMA Disaster Recovery Centers (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...

  7. Centering in Japanese Discourse

    CERN Document Server

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


    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.

  8. Accredited Birth Centers (United States)

    ... 9743 Accredited since January 2016 98 Bright Eyes Midwifery and Wild Rivers Women's Health Accredited 29135 Ellensburg ... Accredited since November 2015 96 Footprints in Time Midwifery Services and Birth Center Accredited 351 N. Water ...

  9. Advanced Missile Signature Center (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,...

  10. Brownian Motion, "Diverse and Undulating"

    CERN Document Server

    Duplantier, Bertrand


    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.

  11. The Tribology of Undulated Surfaces (United States)


    for it is generally hard to lubricate. Rabinowicz [10] has shown, for example, that the common liquid lubricants are essentially ineffective for...Tibology, ASME Trans., 107, pp4 5 2 -4 6 2 (1985). [101 Rabinowicz , E., "Boundary Lubrication of Titanium," Proceedings of the Fifth World Petroleum

  12. Oil Reserve Center Established

    Institute of Scientific and Technical Information of China (English)


    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.

  13. Data center cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Chainer, Timothy J; Dang, Hien P; Parida, Pritish R; Schultz, Mark D; Sharma, Arun


    A data center cooling system may include heat transfer equipment to cool a liquid coolant without vapor compression refrigeration, and the liquid coolant is used on a liquid cooled information technology equipment rack housed in the data center. The system may also include a controller-apparatus to regulate the liquid coolant flow to the liquid cooled information technology equipment rack through a range of liquid coolant flow values based upon information technology equipment temperature thresholds.

  14. National Biocontainment Training Center (United States)


    than ever before as scientists push to understand the pathology and develop diagnostics, vaccines and therapeutics for deadly diseases like Ebola...Hardcastle, Vickie Jones, Sheri Leavitt, and Belinda Rivera. Gulf Coast Consortium Postdoctoral Veterinary Training Program - A clinical veterinarian from...the Center for Comparative Medicine at Baylor College of Medicine in Houston and a veterinarian from the University of Texas Health Science Center

  15. Engineer Research and Development Center's Materials Testing Center (MTC) (United States)

    Federal Laboratory Consortium — The Engineer Research and Development Center's Materials Testing Center (MTC) is committed to quality testing and inspection services that are delivered on time and...

  16. "Infotonics Technology Center"

    Energy Technology Data Exchange (ETDEWEB)

    Fritzemeier, L. [Infotonics Technology Center Inc., Canandaigua, NY (United States); Boysel, M. B. [Infotonics Technology Center Inc., Canandaigua, NY (United States); Smith, D. R. [Infotonics Technology Center Inc., Canandaigua, NY (United States)


    During this grant period July 15, 2002 thru September 30, 2004, the Infotonics Technology Center developed the critical infrastructure and technical expertise necessary to accelerate the development of sensors, alternative lighting and power sources, and other specific subtopics of interest to Department of Energy. Infotonics fosters collaboration among industry, universities and government and operates as a national center of excellence to drive photonics and microsystems development and commercialization. A main goal of the Center is to establish a unique, world-class research and development facility. A state-of-the-art microsystems prototype and pilot fabrication facility was established to enable rapid commercialization of new products of particular interest to DOE. The Center has three primary areas of photonics and microsystems competency: device research and engineering, packaging and assembly, and prototype and pilot-scale fabrication. Center activities focused on next generation optical communication networks, advanced imaging and information sensors and systems, micro-fluidic systems, assembly and packaging technologies, and biochemical sensors. With targeted research programs guided by the wealth of expertise of Infotonics business and scientific staff, the fabrication and packaging facility supports and accelerates innovative technology development of special interest to DOE in support of its mission and strategic defense, energy, and science goals.

  17. Hospitals report on cancer centers. (United States)

    Rees, T


    Woman's Hospital, Baton Rouge, La., is first-place winner among cancer centers. Holy Cross Hospital's Michael and Dianne Bienes Comprehensive Cancer Center, Ft. Lauderdale, Fla., is named second; and, Cardinal Health System's Ball Cancer Center, Muncie, Ind., third.

  18. International Water Center (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. Lied Transplant Center

    Energy Technology Data Exchange (ETDEWEB)



    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.

  20. Data Center Energy Retrofits


    PervilÀ, Mikko


    Within the field of computer science, data centers (DCs) are a major consumer of energy. A large part of that energy is used for cooling down the exhaust heat of the servers contained in the DCs. This thesis describes both the aggregate numbers of DCs and key flagship installations in detail. We then introduce the concept of Data Center Energy Retrofits, a set of low cost, easy to install techniques that may be used by the majority of DCs for reducing their energy consumption. The main c...

  1. User Centered Design

    DEFF Research Database (Denmark)

    Egbert, Maria; Matthews, Ben


    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...


    Energy Technology Data Exchange (ETDEWEB)



    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. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)



    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.

  4. Center for Botanical Interaction Studies (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...

  5. Data Analysis and Assessment Center (United States)

    Federal Laboratory Consortium — The DoD Supercomputing Resource Center (DSRC) Data Analysis and Assessment Center (DAAC) provides classified facilities to enhance customer interactions with the ARL...

  6. 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


    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

  7. User-Centered Design through Learner-Centered Instruction (United States)

    Altay, Burçak


    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…

  8. Economics of data center optics (United States)

    Huff, Lisa


    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.

  9. vCenter troubleshooting

    CERN Document Server

    Mills, Chuck


    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.

  10. Mobile PET Center Project (United States)

    Ryzhikova, O.; Naumov, N.; Sergienko, V.; Kostylev, V.


    Positron emission tomography is the most promising technology to monitor cancer and heart disease treatment. Stationary PET center requires substantial financial resources and time for construction and equipping. The developed mobile solution will allow introducing PET technology quickly without major investments.

  11. Data Center Site Redundancy


    Brotherton, H M; Dietz, J. Eric


    Commonly, disaster contingency calls for separation of location for redundant locations to maintain the needed redundancy. This document addresses issues for the data center redundancy, including limits to the distribution, distance and location that may impact on the efficiency or energy.

  12. Alternative Fuels Data Center

    Energy Technology Data Exchange (ETDEWEB)



    Fact sheet describes the Alternative Fuels Data Center, which provides information, data, and tools to help fleets and other transportation decision makers find ways to reduce petroleum consumption through the use of alternative and renewable fuels, advanced vehicles, and other fuel-saving measures.

  13. School Based Health Centers (United States)

    Children's Aid Society, 2012


    School Based Health Centers (SBHC) are considered by experts as one of the most effective and efficient ways to provide preventive health care to children. Few programs are as successful in delivering health care to children at no cost to the patient, and where they are: in school. For many underserved children, The Children's Aid Society's…

  14. Carolinas Energy Career Center

    Energy Technology Data Exchange (ETDEWEB)

    Classens, Anver; Hooper, Dick; Johnson, Bruce


    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.

  15. Starting a sleep center. (United States)

    Epstein, Lawrence J; Valentine, Paul S


    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.

  16. Memorial Alexander Center

    Directory of Open Access Journals (Sweden)

    AECK Associates, Arquitectos


    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.

  17. Design of a BiomimeticUndulating Fin Driven Propulsor and Numerical Analysis on lts Motion%仿生波动鳍推进器设计及运动学仿真分析

    Institute of Scientific and Technical Information of China (English)

    何建慧; 章永华


    On the basis of biological research achievement of stingray pectoral fins,we carried out bionic design from the inspiration of its morphology and structure characteristics. A two-dimensional mathematic model for the undulating motion was established. Based on the CFD( Computational Fluid Dynamics) technology,the unsteady incompressible navier-stokes equation and continuity equation was solved using uncoupled implicit method. The calculation area was discreted using triangular unstructured grid. The change of non-dimensional drag coefficient with time was presented under the different kinematic parameters. The simulation results indicate that the propulsion force was increased linearly with the increase of undulating frequency,amplitude and wavelength. However,the propulsion stability was decreased with them. The simulation results provide valuable details for further understanding of propulsion principle of biomimetic undulating fin as well as for its optimal design.%以鳐鱼为仿生对象,基于两侧胸鳍的生物学研究成果,对鳐鱼的胸鳍进行形态和结构上的仿生设计。建立仿生鳍波动的二维数学模型。基于计算流体动力学( CFD:Computational Fluid Dynamics)技术,采用非耦合隐式求解非定常不可压缩N-S方程和连续性方程,利用三角形非结构网格对计算区域进行离散,比较分析了不同运动学参数下仿生鳍无量纲阻力系数随时间的变化规律。从仿真结果知:仿生鳍推进力随着波动频率的增加、波幅的增加以及波长的增长而近似线性增大,而游动稳定性则与之相反。该仿真结果为深入了解仿生波动鳍的推进机理提供更为详细的依据,也为仿生波动鳍的优化设计提供参考。

  18. Entanglement with Centers

    CERN Document Server

    Ma, Chen-Te


    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...

  19. Home media center


    Valverde Martinez, Juan Miguel


    One of the most popular indoor entertainment systems nowadays is related to playing multimedia files, not only at home but also in public events such as watching movies in cinemas or playing music in nightclubs or pubs. Developers are responsible for making this easier and innovating in the development of these systems in different ways. This project's goal was to develop a home media center which allows the user to play multimedia files easily. In addition, the development was intended t...


    Energy Technology Data Exchange (ETDEWEB)



    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.

  1. Memorial Center - Milwaukee

    Directory of Open Access Journals (Sweden)

    Saarinen, Eero


    Full Text Available El Memorial Center de Milwaukee ha sido erigido en la parte más alta de la ciudad, coronando una enorme colina que domina ampliamente el conjunto urbano y un hermoso lago. Su emplazamiento, al final de un puente de grandes dimensiones, exigía que fuese tratado en armonía con éste, habiéndose adoptado por ello el sistema de colocar la edificación reposando sobre una planta totalmente diáfana que deja vista la estructura, cuyos esbeltos soportes dan sensación de monumentalidad.


    Energy Technology Data Exchange (ETDEWEB)



    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.

  3. Sustainable Biofuels Development Center

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  4. Data center coolant switch

    Energy Technology Data Exchange (ETDEWEB)

    Iyengar, Madhusudan K.; Parida, Pritish R.; Schultz, Mark D.


    A data center cooling system is operated in a first mode; it has an indoor portion wherein heat is absorbed from components in the data center, and an outdoor heat exchanger portion wherein outside air is used to cool a first heat transfer fluid (e.g., water) present in at least the outdoor heat exchanger portion of the cooling system during the first mode. The first heat transfer fluid is a relatively high performance heat transfer fluid (as compared to the second fluid), and has a first heat transfer fluid freezing point. A determination is made that an appropriate time has been reached to switch from the first mode to a second mode. Based on this determination, the outdoor heat exchanger portion of the data cooling system is switched to a second heat transfer fluid, which is a relatively low performance heat transfer fluid, as compared to the first heat transfer fluid. It has a second heat transfer fluid freezing point lower than the first heat transfer fluid freezing point, and the second heat transfer fluid freezing point is sufficiently low to operate without freezing when the outdoor air temperature drops below a first predetermined relationship with the first heat transfer fluid freezing point.

  5. National Center for Biotechnology Information (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 ...

  6. Center for Beam Physics, 1992

    Energy Technology Data Exchange (ETDEWEB)


    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. Daugherty Memorial Assessment Center (DMAC) (United States)

    Federal Laboratory Consortium — Daugherty Memorial Assessment Center (DMAC) is a 39,000-square-foot facility that doubles the warfare center's high-secured performance assessment capabilities. DMAC...

  8. Italy INAF Data Center Report (United States)

    Negusini, M.; Sarti, P.


    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.

  9. VT Designated Village Centers Boundary (United States)

    Vermont Center for Geographic Information — This community revitalization program helps maintain or evolve small to medium-sized historic centers with existing civic and commercial buildings. The designation...

  10. Center for Veterinary Medicine (CVM) (United States)

    Federal Laboratory Consortium — As seen on the center's logo, the mission statement for FDA's Center for Veterinary Medicine (CVM) reads: "Protecting Human and Animal Health." To achieve this broad...

  11. Center for Prostate Disease Research (United States)

    Federal Laboratory Consortium — The Center for Prostate Disease Research is the only free-standing prostate cancer research center in the U.S. This 20,000 square foot state-of-the-art basic science...

  12. Contact Center Manager Administration (CCMA) (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...

  13. National Center on Family Homelessness (United States)

    ... You are here Home National Center on Family Homelessness Center A staggering 2.5 million children are ... raise awareness of the current state of child homelessness in the United States, documents the number of ...

  14. On chains of centered valuations

    Directory of Open Access Journals (Sweden)

    Rachid Chibloun


    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.


    California State Dept. of Education, Sacramento.



    Energy Technology Data Exchange (ETDEWEB)



    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

  17. Citizen centered design

    Directory of Open Access Journals (Sweden)

    Ingrid Mulder


    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.

  18. Mi Pueblo Food Center

    Directory of Open Access Journals (Sweden)

    Alexis A. Babb


    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.

  19. Supernova Science Center

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Woosley


    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.

  20. Industrial Assessment Center Program

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Dereje Agonafer


    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.

  1. Concurrent engineering research center (United States)

    Callahan, John R.


    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.

  2. The Center is Everywhere

    CERN Document Server

    Weinberg, David H


    "The Center is Everywhere" is a sculpture by Josiah McElheny, currently (through October 14, 2012) on exhibit at the Institute of Contemporary Art, Boston. The sculpture is based on data from the Sloan Digital Sky Survey (SDSS), using hundreds of glass crystals and lamps suspended from brass rods to represent the three-dimensional structure mapped by the SDSS through one of its 2000+ spectroscopic plugplates. This article describes the scientific ideas behind this sculpture, emphasizing the principle of the statistical homogeneity of cosmic structure in the presence of local complexity. The title of the sculpture is inspired by the work of the French revolutionary Louis Auguste Blanqui, whose 1872 book "Eternity Through The Stars: An Astronomical Hypothesis" was the first to raise the spectre of the infinite replicas expected in an infinite, statistically homogeneous universe. Puzzles of infinities, probabilities, and replicas continue to haunt modern fiction and contemporary discussions of inflationary cosmo...

  3. Regional Warning Center Sweden (United States)

    Lundstedt, Henrik

    RWC-Sweden is operated by the Lund division of the Swedish Institute of Space Physics located at IDEON, a Science Research Technology Park. The Institute of Technology of Lund and Lund University are just adjacent to IDEON. This creates a lot of synergy effects. Copenhagen, with the Danish National Space Center DNSC), and Atmosphere Space Research Division of Danish Meteorological Institute (DMI), is 45 min away via the bridge. The new LOIS Space Centre is located two hours away by car, north of Lund and just outside V¨xj¨. The IRF Lund a o division is aiming at becoming a "Solar and Space Weather Center". We focus on solar magnetic activity, its influence on climate and on space weather effects such the effect of geomagnetically induced currents (GIC). Basic research: A PostDoc position on "Solar Magnetic Activity: Topology and Predictions has recently been created. Research is carried on to improve predictions of solar magnetic activity. Preparations for using upcoming SDO vector magnetic fields are ongoing. Predictions: RWC-Sweden offers real-time forecasts of space weather and space weather effects based on neural networks. We participated in the NASA/NOAA Cycle 24 Prediction Panel. We have also participated in several ESA/EU solar-climate projects New observation facilities: Distributed, wide-area radio facility (LOIS) for solar (and other space physics) observations and a guest prof: Radio facility about 200 km distant, outside V¨xj¨ (Sm˚ a o aland), in Ronneby (Blekinge) and Lund (Sk˚ ane) is planned to be used for tracking of CMEs and basic solar physics studies of the corona. The LOIS station outside V¨xj¨ has a o been up and running for the past three years. Bo Thidé has joined the Lund division e as a guest prof. A new magnetometer at Risinge LOIS station has been installed an calibrated and expected to be operational in March, 2008.

  4. Satellite medical centers project (United States)

    Aggarwal, Arvind


    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.

  5. Center for Rehabilitation Sciences Research (United States)

    Federal Laboratory Consortium — The Center for Rehabilitation Sciences Research (CRSR) was established as a research organization to promote successful return to duty and community reintegration of...

  6. Energetics Manufacturing Technology Center (EMTC) (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...

  7. Center for Environmental Health Sciences (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...

  8. Consolidated Copayment Processing Center (CCPC) (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 of...

  9. Center for Neuroscience & Regenerative Medicine (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...

  10. NASA New England Outreach Center (United States)


    The NASA New England Outreach Center in Nashua, New Hampshire was established to serve as a catalyst for heightening regional business awareness of NASA procurement, technology and commercialization opportunities. Emphasis is placed on small business participation, with the highest priority given to small disadvantaged businesses, women-owned businesses, HUBZone businesses, service disabled veteran owned businesses, and historically black colleges and universities and minority institutions. The Center assists firms and organizations to understand NASA requirements and to develop strategies to capture NASA related procurement and technology opportunities. The establishment of the NASA Outreach Center serves to stimulate business in a historically underserved area. NASA direct business awards have traditionally been highly present in the West, Midwest, South, and Southeast areas of the United States. The Center guides and assists businesses and organizations in the northeast to target opportunities within NASA and its prime contractors and capture business and technology opportunities. The Center employs an array of technology access, one-on-one meetings, seminars, site visits, and targeted conferences to acquaint Northeast firms and organizations with representatives from NASA and its prime contractors to learn about and discuss opportunities to do business and access the inventory of NASA technology. This stimulus of interaction also provides firms and organizations the opportunity to propose the use of their developed technology and ideas for current and future requirements at NASA. The Center provides a complement to the NASA Northeast Regional Technology Transfer Center in developing prospects for commercialization of NASA technology. In addition, the Center responds to local requests for assistance and NASA material and documents, and is available to address immediate concerns and needs in assessing opportunities, timely support to interact with NASA Centers on

  11. Clean Energy Application Center

    Energy Technology Data Exchange (ETDEWEB)

    Freihaut, Jim


    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

  12. Stennis Visitors Center and Administrative Complex (United States)


    This aerial view shows the John C. Stennis Space Center Visitors Center and main Administrative complex. The Stennis Space Center in Hancock County, Mississippi is NASA's lead center for rocket propulsion testing and for commercial remote sensing.

  13. Allegheny County Kane Regional Center Census (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Total number of residents in each Kane Regional Center facility by race and gender. The Kane Regional Centers are skilled nursing and rehabilitation centers run by...

  14. 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


    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).

  15. 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


    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.

  16. The generation of germinal centers

    NARCIS (Netherlands)

    Kroese, Fransciscus Gerardus Maria


    Germinal centers are clusters of B lymphoblastoid cells that develop after antigenic stimulation in follicles of peripheral lymphoid organs. These structures are thought to play a major role in the generation of B memory cells. This thesis is dealing with several aspects of these germinal centers. I

  17. Learning Centers: Development and Operation. (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…

  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


    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. PTSD: National Center for PTSD

    Medline Plus

    Full Text Available ... Section Home PTSD Overview PTSD Basics Return from War Specific to Women Types of Trauma War Terrorism Violence and Abuse Disasters Is it PTSD? ... Combat Veterans & their Families Readjustment Counseling (Vet Centers) War Related Illness & Injury Study Center Homeless Veterans Returning ...

  1. User-Centered Design Gymkhana


    Garreta Domingo, Muriel; Almirall Hill, Magí; Mor Pera, Enric


    The User-centered design (UCD) Gymkhana is a tool for human-computer interaction practitioners to demonstrate through a game the key user-centered design methods and how they interrelate in the design process.The target audiences are other organizational departments unfamiliar with UCD but whose work is related to the definition, cretaion, and update of a product service.

  2. Information Sciences: Information Centers and Special Libraries. (United States)


  3. Pengembangan Model Manajemen ICT Center

    Directory of Open Access Journals (Sweden)

    Hakkun Elmunsyah


    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

  4. Emergency Operations Center ribbon cutting (United States)


    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.

  5. Center for Beam Physics, 1993

    Energy Technology Data Exchange (ETDEWEB)


    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.

  6. Shopping Malls - ShoppingCenters (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...

  7. Clean Energy Solutions Center Services

    Energy Technology Data Exchange (ETDEWEB)


    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.

  8. Student-Centered Reading Activities. (United States)

    Moffett, James; Wagner, Betty Jane


    Offers student-centered reading activities designed to bring students to reading maturity and involvement in literature. Discusses partner reading, dramatizing and performing texts, transforming texts, journal writing, discussion, and writing. (PRA)

  9. Center for Creative Studies, Detroit (United States)

    AIA Journal, 1976


    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)

  10. Electricity Infrastructure Operations Center (EIOC) (United States)

    Federal Laboratory Consortium — The Electricity Infrastructure Operations Center (EIOC) at PNNL brings together industry-leading software, real-time grid data, and advanced computation into a fully...

  11. Aim to International Shipping Center

    Institute of Scientific and Technical Information of China (English)

    Hu Wenxiu


    @@ 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.

  12. Poison control center - emergency number (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 ...


    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...

  14. Kennedy Space Center Design Visualization (United States)

    Humeniuk, Bob


    Perform simulations of ground operations leading up to launch at Kennedy Space Center and Vandenberg Air Force Base in CA since 1987. We use 3D Laser Scanning, Modeling and Simulations to verify that operations are feasible, efficient and safe.

  15. Telework centers as local development

    DEFF Research Database (Denmark)

    Lorentzen, Anne


    projects. A record of the development challenges of the two host municipalities Jammerbugt and Brønderslev, to contextualize the telework centers in the local context. And finally a preliminary analysis and discussion of the two telework centers in relation to their potential community benefits......This paper discusses the establishment of distant work centers as an element in local development strategies in rural areas with a particular view on two new telework centers in Region North Denmark Distant work is a phenomenon on the rise, due to the development of the internet on the one hand...... regardless of location, as long as there is access to internet. Not only firms, but individual labor is potentially liberated from the logic of physical location and proximity. Technically speaking ‘geography is dead’ and the clustering of new service jobs in big cities is no longer a technical necessity...

  16. PTSD: National Center for PTSD

    Medline Plus

    Full Text Available ... Espanol Apps, Videos and More Mobile Apps Videos Web Links PTSD Site Search For Professionals Professional Section ... Education Handouts Manuals Mobile Apps Publications Toolkits Videos Web Links Advanced Search About Us National Center for ...

  17. FEMA Disaster Recovery Centers - KML (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...

  18. National Center for Health Statistics (United States)

    ... Submit Search The CDC National Center for Health Statistics Note: Javascript is disabled or is not supported ... Survey of Family Growth Vital Records National Vital Statistics System National Death Index Provider Surveys National Health ...

  19. Records Center Program Billing System (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...

  20. Parent and Child Living Centers. (United States)

    Pushaw, David R.


    Parent and child living centers offer a program to improve parenting skills with areas of learning including child growth and development, family management, home care and repair, and personal growth and development. (MM)

  1. Engineering Technical Support Center (ETSC) (United States)

    ETSC is EPA’s technical support and resource centers responsible for providing specialized scientific and engineering support to decision-makers in the Agency’s ten regional offices, states, communities, and local businesses.

  2. Human-Centered Design Capability (United States)

    Fitts, David J.; Howard, Robert


    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.

  3. Transportation Research & Analysis Computing Center (United States)

    Federal Laboratory Consortium — The technical objectives of the TRACC project included the establishment of a high performance computing center for use by USDOT research teams, including those from...

  4. Joint Center for Robotics (JCR) (United States)


    Unclassified 1 Joint Center for Robotics (JCR) Dr. Jim Overholt 15 April 2008 DISTRIBUTION STATEMENT A. Approved for public release; distribution is...REPORT DATE APR 2008 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Joint Center for Robotics (JCR) 5a. CONTRACT NUMBER 5b. GRANT...ANSI Std Z39-18 Unclassified 2 TARDEC JCR Robotics CAST Projects & Cells “White Hat” Organization - Understand the needs of the user and create

  5. Italy INAF Analysis Center Report (United States)

    Negusini, M.; Sarti, P.


    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.

  6. Centered Sublattice and its Application

    Institute of Scientific and Technical Information of China (English)

    宋振明; 徐扬; 等


    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.

  7. User-Centered Data Management

    CERN Document Server

    Catarci, Tiziana; Kimani, Stephen


    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

  8. Correlations between Abelian monopoles and center vortices (United States)

    Hosseini Nejad, Seyed Mohsen; Deldar, Sedigheh


    We study the correlations between center vortices and Abelian monopoles for SU(3) gauge group. Combining fractional fluxes of monopoles, center vortex fluxes are constructed in the thick center vortex model. Calculating the potentials induced by fractional fluxes constructing the center vortex flux in a thick center vortex-like model and comparing with the potential induced by center vortices, we observe an attraction between fractional fluxes of monopoles constructing the center vortex flux. We conclude that the center vortex flux is stable, as expected. In addition, we show that adding a contribution of the monopole-antimonopole pairs in the potentials induced by center vortices ruins the Casimir scaling at intermediate regime.

  9. 仿生蓝点魟胸鳍在两种波动模式下推进力的比较%Comparative Analysis of Thrust Generation of Biomimetic Bluespotted Stingray Pectoral Fin under Two Undulating Propulsion Patterns

    Institute of Scientific and Technical Information of China (English)

    章永华; 何建慧; 贾来兵


    Fishes that rely on fin undulating motion to propel themselves usually have an extraordinary stability and maneuvering. Among them, the propulsion patterns are generally divided into two types according to the amplitude envelop formation of travelling wave, i.e. amplitude gradually increases from anterior to posterior and amplitude that stay consistent along the fin. A biomimetic pectoral fin of bluespotted ray is developed, and an experiment is implemented to investigate the differences of thrust between the two propulsion patterns under different undulating frequency, amplitude and wavelength. The experimental results illustrate that the propulsion thrust mainly increases with the increase of undulating frequency, amplitude and wavelength under both propulsion patterns. However, the thrust generated under the pattern with amplitude gradually increases from anterior to posterior is always larger than the one generated under the pattern with amplitude that stay consistent along the fin under the same kinematic parameters. Thus, for a further investigation to the experiment observations, a two dimensional biomimetic pectoral fin model is established. By taking advantage of finite volume method(FVM), the model and its corresponding computational region were dissociated. Then, the propulsion thrust of the two patterns is calculated based on computational fluid dynamic(CFD). A comparative analysis of thrust generation under different frequency, amplitude and wavelength is carried out. Finally, the pressure contour and vortex distribution in the wake of the fin is illustrated. The current findings are used for propulsion pattern selection of biomimetic fin to achieve efficient and reliable application.%依靠鱼鳍波动推进的鱼类通常具备极强的游动稳定性和机动性能,在这些鱼类中,根据鱼鳍波状运动形成行波波幅包络线形式的不同,鱼鳍波动模式主要有摆幅从前往后逐渐增大和摆幅保持不变两种.设计出一种

  10. The Research Role of a National Center. (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…

  11. Advanced Call Center Supporting WAP Access

    Institute of Scientific and Technical Information of China (English)


    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.

  12. Finding Communities by Their Centers (United States)

    Chen, Yan; Zhao, Pei; Li, Ping; Zhang, Kai; Zhang, Jie


    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.

  13. Center Innovation Fund: KSC CIF Program (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...


    Directory of Open Access Journals (Sweden)



    Full Text Available The investigation on relationships between responsibility centers and budgets supposes examining the influence of management control over the entity management structures. Thus, responsibility centers help to streamline the management structure and ensure the implementation of the budget system into practice. Budgeting refers to the transformation of financial plans into monetary units. The pragmatic approach of the relationship between responsibility centers and budgets is analyzed on the basis of Romanian entities in the regulated market of the Bucharest Stock Exchange. The fact that entities which show the management structure and at the same time show the income and expense budget makes us claim that both have an important role to play in implementing the entity strategies.

  15. Self-Access Centers: Maximizing Learners’ Access to Center Resources

    Directory of Open Access Journals (Sweden)

    Mark W. Tanner


    Full Text Available Originally published in TESL-EJ March 2009, Volume 12, Number 4 ( 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.

  16. NASA(Field Center Based) Technology Commercialization Centers (United States)


    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.

  17. User-centered agile method

    CERN Document Server

    Deuff, Dominique


    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

  18. New center for IT research

    Directory of Open Access Journals (Sweden)

    Larry R Dalton


    The motivation for creating such a center is quite obvious. Despite the ‘dot com’ crash, IT continues to be the fastest growing and dominant component of world economy. Computing power and the ability to rapidly move information around the world are, of course, important drivers of that IT economy.

  19. Center for Intelligent Control Systems (United States)


    CENTER FOR INTELLIGENT CONTROL SYSTEMS Brown Umiversity Harvard University Marsachomtta Institute of Tecnology PUBLICATIONS LIST CICS Number Authors...Equivalence of the Auction Algorithm for 11/1/92 Assignment and die e-Relaxation (Preflow- Push ) Method for Min Cost Flow 26

  20. Financial Management in Imaging Center

    Directory of Open Access Journals (Sweden)

    Arash Deljou


    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 (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


    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. The DLESE Community Services Center (United States)

    Geary, E.; Aivazian, B.; Manduca, C.; Mogk, D.


    The DLESE Community Services Center (DCSC) is one of several centers recently funded by the National Science Foundation to promote greater and more effective use of Digital Library resources. The primary goals of the DCSC are to: (1) increase the current resource user and contributor base to include greater numbers of K-12, informal, and college educators and students, (2) diversify the DLESE user and contributor base to include rich and robust representation of ethnic, cultural, and differently-abled groups, (3) improve the ability of users and contributors to easily find, adapt, and use high quality digital resources in their classrooms, laboratories, and communities and (4) demonstrate how DLESE can support community activity addressing issues in geoscience education. During the course of the next three years we will: (a) solicit, create, and disseminate "exemplars" that highlight effective digital resource use in a variety of diverse educational settings, (b) continue to support and promote on-line DLESE community services, and (c) work to develop a DLESE ambassadors outreach program involving educators, scientists, and students working across the Earth, space, and environmental sciences. Collaborations with the DLESE Evaluation and Data Centers, collection builders, the DLESE Program Center staff, as well as diverse audience groups will be a key focus of our efforts. We invite you to join us as we work to build and support the next generation of digital services and resources for educators and students at all levels.

  3. Kempinski Hotel Beijing Lufthansa Center

    Institute of Scientific and Technical Information of China (English)


    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. VMware vCenter cookbook

    CERN Document Server

    Kuminsky, Konstantin


    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.

  5. The Mud Center: Recapturing Childhood. (United States)

    Jensen, Becky J.; Bullard, Julie A.


    Describes a Montana child development center's creation of an area in which children could enjoy messy, creative, sensory experiences playing with mud and a wide variety of outdoor props. Discusses how mud play contributed to young children's emerging interests and provided opportunities for expressing creativity, enhancing fine motor skills, and…

  6. An International Development Technology Center (United States)

    Morgan, Robert P.


    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)

  7. ITMO Photonics: center of excellence (United States)

    Voznesenskaya, Anna; Bougrov, Vladislav; Kozlov, Sergey; Vasilev, Vladimir


    ITMO University, the leading Russian center in photonics research and education, has the mission to train highlyqualified competitive professionals able to act in conditions of fast-changing world. This paradigm is implemented through creation of a strategic academic unit ITMO Photonics, the center of excellence concentrating organizational, scientific, educational, financial, laboratory and human resources. This Center has the following features: dissemination of breakthrough scientific results in photonics such as advanced photonic materials, ultrafast optical and quantum information, laser physics, engineering and technologies, into undergraduate and graduate educational programs through including special modules into the curricula and considerable student's research and internships; transformation of the educational process in accordance with the best international educational practices, presence in the global education market in the form of joint educational programs with leading universities, i.e. those being included in the network programs of international scientific cooperation, and international accreditation of educational programs; development of mechanisms for the commercialization of innovative products - results of scientific research; securing financial sustainability of research in the field of photonics of informationcommunication systems via funding increase and the diversification of funding sources. Along with focusing on the research promotion, the Center is involved in science popularization through such projects as career guidance for high school students; interaction between student's chapters of international optical societies; invited lectures of World-famous experts in photonics; short educational programs in optics, photonics and light engineering for international students; contests, Olympics and grants for talented young researchers; social events; interactive demonstrations.

  8. Directory of Manufacturing Research Centers (United States)


    L. Lehn P. Klinefelter A DoD Information Analysis Center UNCLASSIFIED ECURITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PAGE a. R&D, industrial innovation case histories , and managing innovation. Industry recognizes that research and development are indispensable to the

  9. Adult Learning Center Curriculum Activities. (United States)

    City Univ. of New York, Bronx. Herbert H. Lehman Coll. Inst. for Literacy Studies.

    These curriculum materials were collected from teachers in the Lehman College Adult Learning Center (New York). They include various activities and resources, such as a series of questions about the aims of teaching adults, a list of sources for adult basic education (ABE) materials, poems, and autobiographical materials. Teaching suggestions and…

  10. Research on spatial coherence of undulator source in Shanghai synchrotron radiation facility%上海同步辐射装置波荡器光源空间相干性的研究

    Institute of Scientific and Technical Information of China (English)

    王华; 闫帅; 闫芬; 蒋升; 毛成文; 梁东旭; 杨科; 李爱国; 余笑寒


    利用高斯-谢尔光源模型理论与交叉谱密度函数在自由空间传输的规律,研究了上海同步辐射装置波荡器光源(BL15U)的空间相干性;讨论了预聚焦镜、单色器对光束空间相干性的影响;实验测量了单色光狭缝S2处光束的横向相干长度(Z方向).理论计算表明,S2处光束的横向相干长度为66.5μm,但实验测量结果为27μm.理论与实验相差较大的原因是由于S2上游光学元件预聚焦镜或单色器1期性高频振动导致了光束空间相干性的退化.实验结果表明,上海同步辐射装置波荡器光源已有较强的空间相干性,可以满足微米尺度的硬X射线相干性实验.%Firstly,based on the Gaussian-schell model source theory and the propagation of cross-spectral density function in free space, the spatial coherence of undulator source(BL15U) in Shanghai Synchrotron Radiation Facility is studied.Secondly,the influences of pre-focusing mirror and the monochromator on the beam spatial coherence are discussed.Finally,the spatial coherent length at mono slit S2 is measured.The spatial coherent length at S2 theoretically is 66.5μm,but experimentally is 27μm.This difference is due to the high frequency vibration of pre-focusing mirror or monochromato.Nevertheless,high coherent hard X ray beams can be obtained at the location of experimental sample and many coherent experiments can be fulfilled on this beamline.

  11. What Is A Teacher Education Center? (United States)

    O'Gorman, David E.

    The introductory portion of this report defines teacher education centers and briefly describes their developmental continuum. A synthesis of documents concerning student teaching and teacher education centers is followed by a list of features differentiating conventional programs, student teaching centers, and teacher education centers.…

  12. Counseling Services in Adult Day Care Centers. (United States)

    Zaki, Gamal; Zaki, Sylvia

    Federal support for adult day care centers began in the United States approximately 10 years ago. To examine the counseling practices in the adult day care centers across the country and to explore how the services are affected by the staffing patterns at these centers, 135 centers completed a questionnaire. The questionnaire addressed…

  13. Permanent magnets including undulators and wigglers


    Bahrdt, J.


    After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrat...

  14. Undulating tongue in Wilson′s disease

    Directory of Open Access Journals (Sweden)

    M Nagappa


    Full Text Available We report an unusual occurrence of involuntary movement involving the tongue in a patient with confirmed Wilson′s disease (WD. She manifested with slow, hypophonic speech and dysphagia of 4 months duration, associated with pseudobulbar affect, apathy, drooling and dystonia of upper extremities of 1 month duration. Our patient had an uncommon tongue movement which was arrhythmic. There was no feature to suggest tremor, chorea or dystonia. It might be described as athetoid as there was a writhing quality, but of lesser amplitude. Thus, the phenomenology was uncommon in clinical practice and the surface of the tongue was seen to "ripple" like a liquid surface agitated by an object or breeze. Isolated lingual dyskinesias are rare in WD. It is important to evaluate them for WD, a potentially treatable disorder.

  15. Advanced Call Center Supporting WAP Access

    Institute of Scientific and Technical Information of China (English)

    YUANXiao-hua; CHENJun-liang


    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.

  16. Jellyfish: Networking Data Centers Randomly

    CERN Document Server

    Singla, Ankit; Popa, Lucian; Godfrey, P Brighten


    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.

  17. Rolex learning center English guide

    CERN Document Server

    Della Casa, Francesco


    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.

  18. The Fermilab Particle Astrophysics Center

    Energy Technology Data Exchange (ETDEWEB)


    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.

  19. Learning System Center App Controller

    CERN Document Server

    Naeem, Nasir


    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.

  20. World Reference Center for Arboviruses. (United States)


    viruses from many parts of the world. 7 %, 1.1%vl ’ e- "., Distribution of reagents. The reference center distributed 970 ampoules of reference sera...eight pools of Culiseta melanura collected during 1984 as part of a field study on Lyme disease and other zoonoses in Connecticut. A ninth strain was...dense amorphous masses, were present also in the cytoplasm. Smooth-surfaced reticula occurred in the cytoplasm and contained viral particles in

  1. The Fort Collins Science Center (United States)

    Wilson, Juliette T.; Banowetz, Michele M.


    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.

  2. NCI Technology Transfer Center | TTC (United States)

    The National Cancer Institute’s Technology Transfer Center (TTC) facilitates partnerships between the NIH research laboratories and external partners. With specialized teams, TTC guides the interactions of our partners from the point of discovery to patenting, from invention development to licensing. We play a key role in helping to accelerate development of cutting-edge research by connecting our partners to NIH’s world-class researchers, facilities, and knowledge.

  3. The Scientific Data Management Center


    Shoshani, Arie


    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, ...

  4. Drinfeld center of planar algebra

    CERN Document Server

    Das, Paramita; Gupta, Ved Prakash


    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.

  5. Center for Advanced Propulsion Systems (United States)


    compression ignition ( HCCI ) combustion using the CFR engine described earlier (see Fig. 7.3.5 and Table 7.3.2). The concept of these first experiments was...model of Yang and Martin (1990) can give very good results when applied to either motored, HCCI , or HCSI engines for cases with small pressure...ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION Engine Research Center REPORT NUMBER University of Wisconsin - Madison 1500 Johnson Drive

  6. Clean Energy Solutions Center (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Reategui, S.


    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.

  7. Liquid cooled data center design selection

    Energy Technology Data Exchange (ETDEWEB)

    Chainer, Timothy J.; Iyengar, Madhusudan K.; Parida, Pritish R.


    Input data, specifying aspects of a thermal design of a liquid cooled data center, is obtained. The input data includes data indicative of ambient outdoor temperature for a location of the data center; and/or data representing workload power dissipation for the data center. The input data is evaluated to obtain performance of the data center thermal design. The performance includes cooling energy usage; and/or one pertinent temperature associated with the data center. The performance of the data center thermal design is output.

  8. The Northeast Climate Science Center (United States)

    Ratnaswamy, M. J.; Palmer, R. N.; Morelli, T.; Staudinger, M.; Holland, A. R.


    The Department of Interior Northeast Climate Science Center (NE CSC) is part of a federal network of eight Climate Science Centers created to provide scientific information, tools, and techniques that managers and other parties interested in land, water, wildlife and cultural resources can use to anticipate, monitor, and adapt to climate change. Recognizing the critical threats, unique climate challenges, and expansive and diverse nature of the northeast region, the University of Massachusetts Amherst, College of Menominee Nation, Columbia University, Marine Biological Laboratory, University of Minnesota, University of Missouri Columbia, and University of Wisconsin-Madison have formed a consortium to host the NE CSC. This partnership with the U.S. Geological Survey climate science center network provides wide-reaching expertise, resources, and established professional collaborations in both climate science and natural and cultural resources management. This interdisciplinary approach is needed for successfully meeting the regional needs for climate impact assessment, adaptive management, education, and stakeholder outreach throughout the northeast region. Thus, the NE CSC conducts research, both through its general funds and its annual competitive award process, that responds to the needs of natural resource management partners that exist, in part or whole, within the NE CSC bounds. This domain includes the North Atlantic, Upper Midwest and Great Lakes, Eastern Tallgrass and Big Rivers, and Appalachian Landscape Conservation Cooperatives (LCCs), among other management stakeholders. For example, researchers are developing techniques to monitor tree range dynamics as affected by natural disturbances which can enable adaptation of projected climate impacts; conducting a Designing Sustainable Landscapes project to assess the capability of current and potential future landscapes in the Northeast to provide integral ecosystems and suitable habitat for a suite of

  9. Human-Centered Information Fusion

    CERN Document Server

    Hall, David L


    Information fusion refers to the merging of information from disparate sources with differing conceptual, contextual and typographical representations. Rather than focusing on traditional data fusion applications which have been mainly concerned with physical military targets, this unique resource explores new human-centered trends, such as locations, identity, and interactions of individuals and groups (social networks). Moreover, the book discusses two new major sources of information: human observations and web-based information.This cutting-edge volume presents a new view of multi-sensor d

  10. Multifunctional centers in rural areas

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase


    In the Nordic welfare states (Island, Norway, Sweden, Finland, Denmark), an important principle has hitherto been to allow all citizens access to the same high-quality public services - independent of whether they live in urban or rural areas. In Denmark, however, this principle is gradually being......, and facilities for local associations as theatre scenes and sports halls. The centers should be designed to secure both economies of scale and geographic proximity. Empirical evidence indicates that such large meeting places in fact foster physical and social cohesion, as well as human capital and informal...

  11. NASA Airline Operations Research Center (United States)

    Mogford, Richard H.


    This is a PowerPoint presentation NASA airline operations center (AOC) research. It includes information on using IBM Watson in the AOC. It also reviews a dispatcher decision support tool call the Flight Awareness Collaboration Tool (FACT). FACT gathers information about winter weather onto one screen and includes predictive abilities. It should prove to be useful for airline dispatchers and airport personnel when they manage winter storms and their effect on air traffic. This material is very similar to other previously approved presentations with the same title.

  12. Kennedy Space Center Spaceport Analysis (United States)

    Wary, Samantha A.


    Until the Shuttle Atlantis' final landing on July 21, 2011, Kennedy Space Center (KSC) served as NASA's main spaceport, which is a launch and landing facility for rockets and spacecraft that are attempting to enter orbit. Many of the facilities at KSC were created to assist the Shuttle Program. One of the most important and used facilities is the Shuttle Landing Facility (SLF), This was the main landing area for the return of the shuttle after her mission in space. · However, the SLF has also been used for a number of other projects including straight-line testing by Gibbs Racing, weather data collection by NOAA, and an airfield for the KSC helicopters. This runway is three miles long with control tower at midfield and a fire department located at the end in care of an emergency. This facility, which was part of the great space race, will continue to be used for historical events as Kennedy begins to commercialize its facilities. KSC continues to be an important spaceport to the government, and it will transform into an important spaceport for the commercial industry as well. During my internship at KSC's Center Planning and Development Directorate, I had the opportunity to be a part of the negotiation team working on the agreement for Space Florida to control the Shuttle Landing Facility. This gave me the opportunity to learn about all the changes that are occurring here at Kennedy Space Center. Through various meetings, I discovered the Master Plan and its focus is to transform the existing facilities that were primarily used for the Shuttle Program, to support government operations and commercial flights in the future. This. idea is also in a new strategic business plan and completion of a space industry market analysis. All of these different documentations were brought to my attention and I. saw how they came together in the discussions of transitioning the SLF to a commercial operator, Space Florida. After attending meetings and partaking in discussions for

  13. Air Risk Information Support Center

    Energy Technology Data Exchange (ETDEWEB)

    Shoaf, C.R.; Guth, D.J. [Environmental Protection Agency, Washington, DC (United States)


    The Air Risk Information Support Center (Air RISC) was initiated in early 1988 by the US Environmental Protection Agency`s (EPA) Office of Health and Environmental Assessment (OHEA) and the Office of Air Quality Planning and Standards (OAQPS) as a technology transfer effort that would focus on providing information to state and local environmental agencies and to EPA Regional Offices in the areas of health, risk, and exposure assessment for toxic air pollutants. Technical information is fostered and disseminated by Air RISCs three primary activities: (1) a {open_quotes}hotline{close_quotes}, (2) quick turn-around technical assistance projects, and (3) general technical guidance projects. 1 ref., 2 figs.

  14. Metals and Ceramics Information Center. (United States)


    Information Center Box 8618 "Cameron Station (2) Ann Arbor, MI 48107 Alexandria, VA 22314 Mr. Ronald D. Brown DCASNA Chemical Propulsion Information Agency...MMh Tmnooq Pv.3wls addw S aidnm ENEfftbY AND CHEMICAL PROCESSES 10*1- R&D t-d P h nmmago * So-s Cnms. a"d W.ft l... *solid MW HmmI..s401 *we *Chmeal P o...staff have attended both the Regional and Annual DROLS Users meetings to be available to assist users of the MM4C and other IAC databses . ’I 40 Z ad C4

  15. Management of nuclear training center

    Energy Technology Data Exchange (ETDEWEB)

    Seo, In Suk; Lee, Han Young; Cho, Boung Jae; Lee, Seung Hee; Lee, Eoi Jin; You, Byung Hoon; Lee, Won Ku; Jeon, Hyung Ryeon; Seo, Kyung Won; Kim, Young Joong; Kim, Ik Hyun; Hyun, Ha Il; Choi, Il Ki; Hong, Choon Sun; Won, Jong Yeul; Joo, Yong Chang; Nam, Jae Yeul; Sin, Eun Jeong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    This report describes the annual results of training courses. The scope and contents are as follows : 1. Regional and interregional training courses, 2. Training courses assisted by foreign experts, 3. Training courses for nuclear industry personnel, 4. Training courses for internal staff-members, 5. Training courses under the law. The nuclear training center executed the open-door training courses for 2,699 engineers/scientists from the regulatory body, nuclear industries, research institutes and other related organizations by means of offering 69 training courses during the fiscal year 1995. (Author) .new.

  16. Large data centers interconnect bottlenecks. (United States)

    Ghiasi, Ali


    Large data centers interconnect bottlenecks are dominated by the switch I/O BW and the front panel BW as a result of pluggable modules. To overcome the front panel BW and the switch ASIC BW limitation one approach is to either move the optics onto the mid-plan or integrate the optics into the switch ASIC. Over the last 4 years, VCSEL based optical engines have been integrated into the packages of large-scale HPC routers, moderate size Ethernet switches, and even FPGA's. Competing solutions based on Silicon Photonics (SiP) have also been proposed for integration into HPC and Ethernet switch packages but with better integration path through the use of TSV (Through Silicon Via) stack dies. Integrating either VCSEL or SiP based optical engines into complex ASIC package that operates at high temperatures, where the required reliability is not trivial, one should ask what is the technical or the economic advantage before embarking on such a complex integration. High density Ethernet switches addressing data centers currently in development are based on 25G NRZ signaling and QSFP28 optical module that can support up to 3.6 Tb of front panel bandwidth.

  17. Midwest Clean Energy Application Center

    Energy Technology Data Exchange (ETDEWEB)

    Cuttica, John; Haefke, Cliff


    The Midwest Clean Energy Application Center (CEAC) was one of eight regional centers that promoted and assisted in transforming the market for combined heat and power (CHP), waste heat to power (WHP), and district energy (DE) technologies and concepts throughout the United States between October 1, 2009 and December 31, 2013. The key services the CEACs provided included: Market Opportunity Analyses – Supporting analyses of CHP market opportunities in diverse markets including industrial, federal, institutional, and commercial sectors. Education and Outreach – Providing information on the energy and non-energy benefits and applications of CHP to state and local policy makers, regulators, energy end-users, trade associations and others. Information was shared on the Midwest CEAC website: Technical Assistance – Providing technical assistance to end-users and stakeholders to help them consider CHP, waste heat to power, and/or district energy with CHP in their facility and to help them through the project development process from initial CHP screening to installation. The Midwest CEAC provided services to the Midwest Region that included the states of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.

  18. Kansas Water Science Center bookmark (United States)



    The U.S. Geological Survey Kansas Water Science Center has collected and interpreted hydrologic information in Kansas since 1895. Data collected include streamflow and gage height, reservoir content, water quality and water quantity, suspended sediment, and groundwater levels. Interpretative hydrologic studies are completed on national, regional, statewide, and local levels and cooperatively funded through more than 40 partnerships with these agencies. The U.S. Geological Survey provides impartial scientific information to describe and understand the health of our ecosystems and environment; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. These collected data are in the National Water Information System, and all results are documented in reports that also are online at Follow the USGS Kansas Water Science Center on Twitter for the most recent updates and other information:

  19. Reinventing the academic health center. (United States)

    Kirch, Darrell G; Grigsby, R Kevin; Zolko, Wayne W; Moskowitz, Jay; Hefner, David S; Souba, Wiley W; Carubia, Josephine M; Baron, Steven D


    Academic health centers have faced well-documented internal and external challenges over the last decade, putting pressure on organizational leaders to develop new strategies to improve performance while simultaneously addressing employee morale, patient satisfaction, educational outcomes, and research growth. In the aftermath of a failed merger, new leaders of The Pennsylvania State University College of Medicine and Milton S. Hershey Medical Center encountered a climate of readiness for a transformational change. In a case study of this process, nine critical success factors are described that contributed to significant performance improvement: performing a campus-wide cultural assessment and acting decisively on the results; making values explicit and active in everyday decisions; aligning corporate structure and governance to unify the academic enterprise and health system; aligning the next tier of administrative structure and function; fostering collaboration and accountability-the creation of unified campus teams; articulating a succinct, highly focused, and compelling vision and strategic plan; using the tools of mission-based management to realign resources; focusing leadership recruitment on organizational fit; and "growing your own" through broad-based leadership development. Outcomes assessment data for academic, research, and clinical performance showed significant gains between 2000 and 2004. Organizational transformation as a result of the nine factors is possible in other institutional settings and can facilitate a focus on crucial quality initiatives.

  20. Center Innovation Fund: AFRC CIF Program (United States)

    National Aeronautics and Space Administration — The Armstrong Flight Research Center is NASA’s primary center for atmospheric flight research and operations, with a vision “to fly what others only...

  1. National Center On Deaf-Blindness (United States)

    ... My Profile Logout Menu NCDB: National Center on Deaf-Blindness NCDB: National Center on Deaf-Blindness Help ... Collaborate Project Staff Service Provider Family Member State Deaf-Blind Projects Click on a state on the ...

  2. New Mexico Museums and Cultural Centers (United States)

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

  3. Center Innovation Fund: JPL CIF Program (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 and...

  4. Center for Food Safety and Applied Nutrition (United States)

    Federal Laboratory Consortium — The Center for Food Safety and Applied Nutrition, known as CFSAN, is one of six product-oriented centers, in addition to a nationwide field force, that carry out the...

  5. 2011 Las Conchas Post Fire Center Index (United States)

    Earth Data Analysis Center, University of New Mexico — This data set consists of photo centers of raw aerial images representing multi-spectral (red, green, blue, near-infrared) digital aerial imagery of the Las Conchas...

  6. Remote Sensing/Geographic Information Systems Center (United States)

    Federal Laboratory Consortium — The RS/GIS Center, located at ERDC's Cold Regions Research and Engineering Laboratory, in Hanover, New Hampshire, is the Corps of Engineers Center of Expertise for...

  7. Competitive Intelligence and the Information Center. (United States)

    Greene, H. Frances


    Examines the competitive intelligence approach to corporate information gathering, and discusses how it differs from the traditional library information center approach. Steps for developing a competitive intelligence system in the library information center are suggested. (33 references) (MES)

  8. Centers for Disease Control and Prevention (United States)

    ... to site content En español Centers for Disease Control and Prevention CDC 24/7: Saving Lives. Protecting People.™ Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People ...

  9. Commission for the Accreditation of Birth Centers (United States)

    ... center staff and your chosen family and friends Music therapy Massage or therapeutic touch Sterile water papules ... CABC accredited birth center does not use certain interventions, such as vacuum assisted delivery, medication to speed ...

  10. Norton & Elaine Sarnoff Center for Jewish Genetics (United States)

    ... how to register! Read more Contact Us The Norton & Elaine Sarnoff Center for Jewish Genetics is a ... part by the Michael Reese Health Trust . © 2016 Norton & Elaine Sarnoff Center for Jewish Genetics

  11. Electrolysis activities at FCH Test Center

    DEFF Research Database (Denmark)

    Ravn Nielsen, Eva; Nygaard, Frederik Berg

    FCH Test Center for fuel cell and hydrogen technologies was established in 2010 at Risø DTU in Denmark. Today, the test center is part of DTU Energy Conversion. The center gives industry access to advanced testing and demonstration of components and systems. A number of national projects and EU...... projects regarding water electrolysis involve FCH Test Center as a partner. This presentation gives an overview of the activities....

  12. MDCC: Multi-Data Center Consistency


    Kraska, Tim; Pang, Gene; Franklin, Michael J.; Madden, Samuel


    Replicating data across multiple data centers not only allows moving the data closer to the user and, thus, reduces latency for applications, but also increases the availability in the event of a data center failure. Therefore, it is not surprising that companies like Google, Yahoo, and Netflix already replicate user data across geographically different regions. However, replication across data centers is expensive. Inter-data center network delays are in the hundreds of milliseconds and vary...

  13. Hermes flight control center: Definition status (United States)

    Letalle, Pierre


    The Hermes Flight Control Center (HFCC) located in Toulouse (France) is described. The center is the third in the world after the American center in Houston and the Soviet center in Kaliningrad. All the Hermes elements, both on board and on the ground will be coordinated by the HFCC for all phases of each mission. Aspects of the detailed definition phase still in the requirements analysis subphase are described. Diagrams are used to illustrate the interplay between the different systems.

  14. Asymmetric k-Center with Minimum Coverage

    DEFF Research Database (Denmark)

    Gørtz, Inge Li


    In this paper we give approximation algorithms and inapproximability results for various asymmetric k-center with minimum coverage problems. In the k-center with minimum coverage problem, each center is required to serve a minimum number of clients. These problems have been studied by Lim et al. [A....... Lim, B. Rodrigues, F. Wang, Z. Xu, k-center problems with minimum coverage, Theoret. Comput. Sci. 332 (1–3) (2005) 1–17] in the symmetric setting....

  15. Improving Student Persistence at the Genesis Center (United States)

    Fritz, Nancy; Alsabek, Barbara Piccirilli


    The Genesis Center is a community-based adult education center located in Providence, Rhode Island. Founded in 1982 to assist immigrants and refugees from Southeast Asia in their transition to life in the United States, the Genesis Center now provides adult education, job training, and child care services to people who have immigrated from all…

  16. Orthographic Contributions to Perceived Word Center (United States)

    Fischer, Martin H.


    We have a surprising tendency to misperceive the center of visually presented words (Fischer, 1996, 2000a, 2000b). To understand the origin of this bias, four experiments assessed the impact of letter font, letter size, and grapheme-phoneme convergences on perceived stimulus center. Fourteen observers indicated the perceived centers of words,…

  17. The Poison Control Center--Its Role (United States)

    Manoguerra, Anthony S.


    Poison Control Centers are being utilized by more schools of pharmacy each year as training sites for students. This paper discusses what such a center is, its services, changes anticipated in the poison center system in the next several years and how they may influence pharmacy education, specifically as it relates to clinical toxicology.…

  18. Star Formation in the Galactic Center

    CERN Document Server

    Kauffmann, Jens


    Research on Galactic Center star formation is making great advances, in particular due to new data from interferometers spatially resolving molecular clouds in this environment. These new results are discussed in the context of established knowledge about the Galactic Center. Particular attention is paid to suppressed star formation in the Galactic Center and how it might result from shallow density gradients in molecular clouds.

  19. Clean Energy Solutions Center Services (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)


    The Clean Energy Solutions Center (Solutions Center) helps governments, advisors and analysts create policies and programs that advance the deployment of clean energy technologies. The Solutions Center partners with international organizations to provide online training, expert assistance, and technical resources on clean energy policy.

  20. The Hospital-Based Drug Information Center. (United States)

    Hopkins, Leigh


    Discusses the rise of drug information centers in hospitals and medical centers, highlighting staffing, functions, typical categories of questions received by centers, and sources used. An appendix of drug information sources included in texts, updated services, journals, and computer databases is provided. Thirteen references are listed. (EJS)