Science.gov

Sample records for multipoint thomson scattering

  1. Multipoint Thomson scattering diagnostic for DIII-D

    NASA Astrophysics Data System (ADS)

    Hsieh, C. L.; Chase, R.; Deboo, J. C.; Evanko, R. G.; Gohil, P.; Snider, R. T.; Stockdale, R. E.

    1988-02-01

    The multipoint Thomson scattering diagnostic for DIII-D has been in operation since early 1987. Its capability of measuring electron temperatures as low as 50 eV at densities of a few times 10 to the 12th/cu cm and a spatial resolution of 1.4 cm in the plasma edge region has been essential in the study of H-mode plasmas. The major components of the diagnositic system consist of a 10-J ruby laser, many stages of funnel shaped beam baffles, stacks of razor blades for viewing and stray light dumps, two wide-angle lenses for the collection of scattered light through re-entrant window ports with protection shutters, 88 fiber bundles 15 m in length for light transmission to an focal length/1.9 spectrometer, an intensified CCD camera system capable of single photon detection, and a VAX computer for hardware control and data processing. The input end of the fiber bundle is made demountable so the view locations can be reconfigured to optimize the spatial resolution for the plasma region of interest.

  2. Multipoint Thomson scattering diagnostic for DIII-D

    NASA Astrophysics Data System (ADS)

    Hsieh, C. L.; Chase, R.; DeBoo, J. C.; Evanko, R. G.; Gohil, P.; Snider, R. T.; Stockdale, R. E.

    1988-08-01

    The multipoint Thomson scattering diagnostic for DIII-D has been in operation since early 1987. Its capability of measuring electron temperatures as low as 50 eV at densities of a few times 1012 cm-3 and a spatial resolution of 1.4 cm in the plasma edge region has been essential in the study of H-mode plasmas. The major components of the diagnostic system consist of a 10-J ruby laser, many stages of funnel-shaped beam baffles, stacks of razor blades for viewing and stray light dumps, two wide-angle lenses for the collection of scattered light through reentrant window ports with protection shutters, 88 fiber bundles 15 m in length for light transmission to an f/1.9 spectrometer, an intensified CCD camera system capable of single-photon detection, and a VAX computer for hardware control and data processing. The input end of the fiber bundle is made demountable so the view locations can be reconfigured to optimize the spatial resolution for the plasma region of interest.

  3. Public Data Set: Control and Automation of the Pegasus Multi-point Thomson Scattering System

    DOE Data Explorer

    Bodner, Grant M. [University of Wisconsin-Madison] (ORCID:0000000324979172); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Reusch, Joshua A. [University of Wisconsin-Madison] (ORCID:0000000284249422); Rodriguez Sanchez, Cuauhtemoc [University of Wisconsin-Madison] (ORCID:0000000334712586); Schlossberg, David J. [University of Wisconsin-Madison] (ORCID:0000000287139448)

    2016-08-12

    This public data set contains openly-documented, machine readable digital research data corresponding to figures published in G.M. Bodner et al., 'Control and Automation of the Pegasus Multi-point Thomson Scattering System,' Rev. Sci. Instrum. 87, 11E523 (2016).

  4. Public Data Set: A Novel, Cost-Effective, Multi-Point Thomson Scattering System on the Pegasus Toroidal Experiment

    DOE Data Explorer

    Schlossberg, David J. [University of Wisconsin-Madison] (ORCID:0000000287139448); Bodner, Grant M. [University of Wisconsin-Madison] (ORCID:0000000324979172); Reusch, Joshua A. [University of Wisconsin-Madison] (ORCID:0000000284249422); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Rodriguez Sanchez, Cuauhtemoc [University of Wisconsin-Madison] (ORCID:0000000334712586)

    2016-08-13

    This public data set contains openly-documented, machine readable digital research data corresponding to figures published in D.J. Schlossberg et. al., 'A Novel, Cost-Effective, Multi-Point Thomson Scattering System on the Pegasus Toroidal Experiment,' accepted for publication in Review of Scientific Instruments.

  5. A parallelized Python based Multi-Point Thomson Scattering analysis in NSTX-U

    NASA Astrophysics Data System (ADS)

    Miller, Jared; Diallo, Ahmed; Leblanc, Benoit

    2014-10-01

    Multi-Point Thomson Scattering (MPTS) is a reliable and accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Nd:YAG (1064 nm) lasers are fired into the plasma with a frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the midplane of the tokamak pick up the light at various radii/scattering angles, and the avalanche photodiode's voltages are added to an MDSplus tree for later analysis. This project ports and optimizes the prior serial IDL MPTS code into a well-documented Python package that runs in parallel. Since there are 30 polychromators in the current NSTX setup (12 more will be added when NSTX-U is completed), using parallelism offers vast savings in performance. NumPy and SciPy further accelerate numerical calculations and matrix operations, Matplotlib and PyQt make an intuitive GUI with plots of the output, and Multiprocessing parallelizes the computationally intensive calculations. The Python package was designed with portability and flexibility in mind so it can be adapted for use in any polychromator-based MPTS system.

  6. A novel, cost-effective, multi-point Thomson scattering system on the Pegasus Toroidal Experiment (invited)

    NASA Astrophysics Data System (ADS)

    Schlossberg, D. J.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Reusch, J. A.; Rodriguez Sanchez, C.

    2016-11-01

    A novel, cost-effective, multi-point Thomson scattering system has been designed, implemented, and operated on the Pegasus Toroidal Experiment. Leveraging advances in Nd:YAG lasers, high-efficiency volume phase holographic transmission gratings, and increased quantum-efficiency Generation 3 image-intensified charge coupled device (ICCD) cameras, the system provides Thomson spectra at eight spatial locations for a single grating/camera pair. The on-board digitization of the ICCD camera enables easy modular expansion, evidenced by recent extension from 4 to 12 plasma/background spatial location pairs. Stray light is rejected using time-of-flight methods suited to gated ICCDs, and background light is blocked during detector readout by a fast shutter. This ˜103 reduction in background light enables further expansion to up to 24 spatial locations. The implementation now provides single-shot Te(R) for ne > 5 × 1018 m-3.

  7. Control and automation of the Pegasus multi-point Thomson scattering system

    DOE PAGESBeta

    Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.; Reusch, Joshua A.; Rodriguez Sanchez, C.; Schlossberg, David J.

    2016-08-12

    A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. In addition, the system has been upgraded with a set of fast (~1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

  8. Control and automation of the Pegasus multi-point Thomson scattering system

    NASA Astrophysics Data System (ADS)

    Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Reusch, J. A.; Rodriguez Sanchez, C.; Schlossberg, D. J.

    2016-11-01

    A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. Additionally, the system has been upgraded with a set of fast (˜1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

  9. Multi-Point Thomson Scattering System Calibration and Measurements on HBT-EP

    NASA Astrophysics Data System (ADS)

    Donald, G. V.; Levesque, J. P.; Stoafer, C. C.; Mauel, M. E.

    2015-11-01

    A Thomson scattering (TS) system has been successfully installed and calibrated for diagnostics of HBT-EP. The TS system provides three spatial point measurements and has significantly improved upon the previous single point system. Analysis of Rayleigh Scattering was performed for an absolute density calibration of the TS system. Energy fluctuations in the output pulse from the Nd:YAG laser are individually recorded and accounted for using an integrating sphere and photodetector. Te and ne profiles have been investigated for varying wall configuration changes, including insertion of ferritic wall elements. We report our results, for the three spatial points, and measurements of the Te and ne evolution through typical HBT-EP discharges. The three fiber bundle system will be upgraded within the next grant period to allow measurement of ten spatial points. The ten point system will enhance our equilibrium reconstruction capability, improve stability analysis of the HBT-EP discharges, and allow for further understanding of the plasma characteristics during resistive wall mode (RWM) activity and active control experiments. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  10. Thomson scattering from laser plasmas

    NASA Astrophysics Data System (ADS)

    Glenzer, S. H.; Alley, W. E.; Estabrook, K. G.; de Groot, J. S.; Haines, M. G.; Hammer, J. H.; Jadaud, J.-P.; MacGowan, B. J.; Moody, J. D.; Rozmus, W.; Suter, L. J.; Weiland, T. L.; Williams, E. A.

    1999-05-01

    Thomson scattering has recently been introduced as a fundamental diagnostic of plasma conditions and basic physical processes in dense, inertial confinement fusion plasmas. Experiments at the Nova laser facility [E. M. Campbell et al., Laser Part. Beams 9, 209 (1991)] have demonstrated accurate temporally and spatially resolved characterization of densities, electron temperatures, and average ionization levels by simultaneously observing Thomson scattered light from ion acoustic and electron plasma (Langmuir) fluctuations. In addition, observations of fast and slow ion acoustic waves in two-ion species plasmas have also allowed an independent measurement of the ion temperature. These results have motivated the application of Thomson scattering in closed-geometry inertial confinement fusion hohlraums to benchmark integrated radiation-hydrodynamic modeling of fusion plasmas. For this purpose a high energy 4ω probe laser was implemented recently allowing ultraviolet Thomson scattering at various locations in high-density gas-filled hohlraum plasmas. In particular, the observation of steep electron temperature gradients indicates that electron thermal transport is inhibited in these gas-filled hohlraums. Hydrodynamic calculations which include an exact treatment of large-scale magnetic fields are in agreement with these findings. Moreover, the Thomson scattering data clearly indicate axial stagnation in these hohlraums by showing a fast rise of the ion temperature. Its timing is in good agreement with calculations indicating that the stagnating plasma will not deteriorate the implosion of the fusion capsules in ignition experiments.

  11. Scaling Thomson scattering to big machines

    NASA Astrophysics Data System (ADS)

    Bílková, P.; Walsh, M.; Böhm, P.; Bassan, M.; Aftanas, M.; Pánek, R.

    2016-03-01

    Thomson scattering is a widely used diagnostic tool for local measurement of both electron temperature and electron density. It is used for both low and high temperature plasmas and it is a key diagnostic on all fusion devices. The extremely low cross-section of the reaction increases the complexity of the design. Since the early days of fusion, when a simple single point measurement was used, the design moved to a multi-point system with a large number of spatial points, LIDAR system or high repetition Thomson scattering diagnostic which are used nowadays. The initial low electron temperature approximation has been replaced by the full relativistic approach necessary for large devices as well as for ITER with expected higher plasma temperature. Along the way, the different development needs and the issues that exist need to be addressed to ensure that the technique is developed sufficiently to handle challenges of the bigger devices of the future as well as current developments needed for ITER. For large devices, the achievement of the necessary temperature range represents an important task. Both high and low temperatures can be measured, however, a large dynamic range makes the design difficult as size of detector and dynamic range are linked together. Therefore, the requirements of the new devices are extending the boundaries of these parameters. Namely, ITER presents challenges as access is also difficult but big efforts have been made to cope with this. This contribution contains a broad review of Thomson scattering diagnostics used in current devices together with comments on recent progress and speculation regarding future developments needed for future large scale devices.

  12. Thomson scattering at general fusion

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Parfeniuk, D.

    2016-11-01

    This paper provides an overview of the Thomson scattering diagnostic in use at General Fusion, including recent upgrades and upcoming plans. The plasma experiment under examination produces temperatures in the 50-500 eV range with density on the order of 1020 m-3. A four spatial point collection optics scheme has been implemented, with plans to expand to six spatial points. Recent changes to the optics of the laser beamline have reduced stray light. The system employs a frequency doubled Nd:YAG laser (532 nm), a grating spectrometer, and a photomultiplier array based detector.

  13. Deconvolution of H-α profiles measured by Thomson scattering collecting optics

    NASA Astrophysics Data System (ADS)

    LeBlanc, B.; Grek, B.

    1986-08-01

    A method using a multipoint Thomson scattering system to obtain spatially resolved local emissivity is described. The method involves Fourier decomposition with auxiliary constraints. Optimum solution is determined from an analysis of the entropy and the error of the inversion. The technique is applied to H-α emission profiles from the PDX tokamak.

  14. Deconvolution of H-. cap alpha. profiles measured by Thomson scattering collecting optics

    SciTech Connect

    LeBlanc, B.; Grek, B.

    1986-08-01

    A method using a multipoint Thomson scattering system to obtain spatially resolved local emissivity is described. The method involves Fourier decomposition with auxiliary constraints. Optimum solution is determined from an analysis of the entropy and the error of the inversion. The technique is applied to H-..cap alpha.. emission profiles from the PDX tokamak.

  15. Alpha particle collective Thomson scattering in TFTR

    SciTech Connect

    Machuzak, J.S.; Woskov, P.P.; Rhee, D.Y.; Gilmore, J.; Bretz, N.L.; Park, H.K.; Aamodt, R.E.; Cheung, P.Y.; Russell, D.A.; Bindslev, H.

    1993-11-01

    A collective Thomson scattering diagnostic is being implemented on TFTR to measure alpha particle, energetic and thermal ion densities and velocity distributions. A 60 GHz, 0.1-1 kW gyrotron will be used as the transmitter source, and the scattering geometry will be perpendicular to the magnetic field in the extraordinary mode polarization. An enhanced scattered signal is anticipated from fluctuations in the lower hybrid frequency range with this scattering geometry. Millimeter wave collective Thomson scattering diagnostics have the advantage of larger scattering angles to decrease the amount of stray light, and long, high power, modulated pulses to obtain improved signal to noise through synchronous detection techniques.

  16. Thomson scattering on inhomogeneous targets

    SciTech Connect

    Thiele, R.; Sperling, P.; Bornath, Th.; Kraeft, W.-D.; Redmer, R.; Chen, M.; Faeustlin, R. R.; Toleikis, S.; Fortmann, C.; Glenzer, S. H.; Pukhov, A.; Tschentscher, Th.

    2010-11-15

    The introduction of brilliant free-electron lasers enables new pump-probe experiments to characterize warm dense matter states. For instance, a short-pulse optical laser irradiates a liquid hydrogen jet that is subsequently probed with brilliant soft x-ray radiation. The strongly inhomogeneous plasma prepared by the optical laser is characterized with particle-in-cell simulations. The interaction of the soft x-ray probe radiation for different time delays between pump and probe with the inhomogeneous plasma is also taken into account via radiative hydrodynamic simulations. We calculate the respective scattering spectrum based on the Born-Mermin approximation for the dynamic structure factor considering the full density and temperature-dependent Thomson scattering cross section throughout the target. We can identify plasmon modes that are generated in different target regions and monitor their temporal evolution. Therefore, such pump-probe experiments are promising tools not only to measure the important plasma parameters density and temperature but also to gain valuable information about their time-dependent profile through the target. The method described here can be applied to various pump-probe scenarios by combining optical lasers and soft x ray, as well as x-ray sources.

  17. Thomson Scattering Lineshape Fitting for Plasma Diagnostics

    1994-02-04

    HFIT30 is used for interpreting lineshape (intensity versus frequency) data from Thomson and Rayleigh light scattering from a plasma, to obtain temperatures and number densities of the component species in the plasma.

  18. Relativistic Thomson Scatter from Factor Calculation

    2009-11-01

    The purpose of this program is calculate the fully relativistic Thomson scatter from factor in unmagnetized plasmas. Such calculations are compared to experimental diagnoses of plasmas at such facilities as the Jupiter laser facility here a LLNL.

  19. Thomson-scattering systems on TMX

    SciTech Connect

    Goodman, R.K.; Clauser, J.F.; Frank, A.M.; Goerz, D.A.; Lang, D.D.

    1982-01-30

    This report summarizes the criteria and designs that were used for the two TMX Thomson-scattering systems. It describes the optical, mechanical, electronic, and computer analysis features of these installations. A brief discussion of general Thomson-scattering principles and sensitivity limits is given. Also included are some plasma electron temperature and density measurements from TMX that were obtained through the use of these systems.

  20. Calibrations of the LHD Thomson scattering system

    NASA Astrophysics Data System (ADS)

    Yamada, I.; Funaba, H.; Yasuhara, R.; Hayashi, H.; Kenmochi, N.; Minami, T.; Yoshikawa, M.; Ohta, K.; Lee, J. H.; Lee, S. H.

    2016-11-01

    The Thomson scattering diagnostic systems are widely used for the measurements of absolute local electron temperatures and densities of fusion plasmas. In order to obtain accurate and reliable temperature and density data, careful calibrations of the system are required. We have tried several calibration methods since the second LHD experiment campaign in 1998. We summarize the current status of the calibration methods for the electron temperature and density measurements by the LHD Thomson scattering diagnostic system. Future plans are briefly discussed.

  1. Radiation Reaction and Thomson Scattering

    SciTech Connect

    Koga, James

    2007-07-11

    In recent years high power high irradiance lasers of peta-watt order have been or are under construction. In addition, in the next 10 years lasers of unprecedented powers, exa-watt, could be built If lasers such as these are focused to very small spot sizes, extremely high laser irradiances will be achieved. When electrons interact with such a laser, they become highly relativistic over very short time and spatial scales. Usually the motion of an electron under the influence of electromagnetic fields is influenced to a small extent by radiation emission from acceleration. However, under such violent acceleration the amount of radiation emitted by electrons can become so large that significant damping of the electron motion by the emission of this radiation can occur. In this lecture note we will study this problem of radiation reaction by first showing how the equations of motion are obtained. Then, we will examine the problems with such equations and what approximations are made. We will specifically examine the effects of radiation reaction on the Thomson scattering of radiation from counter-streaming laser pulses and high energy electrons through the numerical integration of the equations of motion. We will briefly address the fundamental physics, which can be addressed by using such high irradiance lasers interacting with high energy electrons.

  2. Theory of Thomson scattering in inhomogeneous media

    NASA Astrophysics Data System (ADS)

    Kozlowski, P. M.; Crowley, B. J. B.; Gericke, D. O.; Regan, S. P.; Gregori, G.

    2016-04-01

    Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is particularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous systems.

  3. Theory of Thomson scattering in inhomogeneous media.

    PubMed

    Kozlowski, P M; Crowley, B J B; Gericke, D O; Regan, S P; Gregori, G

    2016-01-01

    Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is particularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous systems. PMID:27068215

  4. Theory of Thomson scattering in inhomogeneous media

    PubMed Central

    Kozlowski, P. M.; Crowley, B. J. B.; Gericke, D. O.; Regan, S. P.; Gregori, G.

    2016-01-01

    Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is particularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous systems. PMID:27068215

  5. Recent improvements in Thomson scattering data analysis

    SciTech Connect

    Tillack, M.S.; Lazarus, E.A.

    1980-04-01

    A new profile analysis package for use with the Thomson scattering data on ISX-B has recently been implemented. The primary feature of this package is a weighted least squares fitting of temperature and density data to generate a representative curve, as opposed to the previous hand-fitting technique. The changes will automate the manner in which data are transmitted and manipulated, without affecting the calculational techniques previously used. The computer programs have also been used to estimate the sensitivity of various plasma quantities to the accuracy of the Thomson scattering data.

  6. Thomson Scattering Measurements on HIT-SI3

    NASA Astrophysics Data System (ADS)

    Everson, C. J.; Morgan, K. D.; Jarboe, T. R.

    2015-11-01

    A multi-point Thomson Scattering diagnostic has been implemented on HIT-SI3 (Helicity Injected Torus - Steady Inductive 3) to measure electron temperature. The HIT-SI3 experiment is a modification of the original HIT-SI apparatus that uses three injectors instead of two. This modification alters the configuration of magnetic fields and thus the plasma behavior in the device. The scientific aim of HIT-SI3 is to develop a deeper understanding of how injector behavior and interactions influence current drive and plasma performance in the spheromak. The Thomson Scattering system includes a 20 J (1 GW pulse) Ruby laser that provides the incident beam, and collection optics that are installed such that measurements can be taken at four spatial locations in HIT-SI3 plasmas. For each measurement point, a 3-channel polychromator is used to detect the relative level of scattering. These measurements allow for the presence of temperature gradients in the spheromak to be investigated. Preliminary HIT-SI3 temperature data are presented and can be compared to predictions from computational models. Work supported by the D.O.E.

  7. Thomson scattering at 250 kHz

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Den Hartog, D. J.

    2015-12-01

    Several upgrades have been applied to the high-repetition-rate Thomson scattering diagnostic on the MST experiment, having increased the rate and number of electron temperature measurements. The detector portion of the Thomson scattering system requires 1.5-2.0 J, 10-20 ns laser pulses at 1064 nm. A high-repetition-rate laser produces suitable pulses for short 3-4 pulse bursts with only 3 μs pulse spacing. Alternatively, the laser timing can be optimized to maximize the number of pulses in a single burst, producing up to 44 pulses at a rate of 100 kHz. The laser follows a master oscillator, power amplifier architecture. Upgrades to the laser include: a new acousto-optic modulator chopped CW laser based master oscillator, a sixth power amplifier, optimized Nd doping within Nd:glass amplifiers via optical modeling of the pump chamber, and a yet to be installed new cavity reflector. Additionally, a new long wavelength filter has been added to the Thomson scattering diagnostic's polychromator based detector, allowing possible detection of net electron drift.

  8. Thomson Scattering Density Calibration by Rayleigh and Rotational Raman Scattering on NSTX

    SciTech Connect

    B.P. LeBlanc

    2008-07-16

    The multi-point Thomson scattering (MPTS) diagnostic measures the profiles of the electron temperature Te(R) and density ne(R) on the horizontal midplane of NSTX. Normal operation makes use of Rayleigh scattering in nitrogen or argon to derive the density profile. While the Rayleigh scattering ne(R) calibration has been validated by comparison with other density measurements and through its correlation with plasma phenomena, it does require dedicated detectors at the laser wavelength in this filter polychromator based diagnostic. The presence of dust and/or stray laser light precludes routine use of these dedicated spectral channels for Thomson scattering measurement. Hence it is of interest to investigate the use of Raman scattering in nitrogen for the purpose of density calibration, since it could free up detection equipment, which could then be used for the instrumentation of additional radial channels. In this paper the viewing optics "geometrical factor" profiles obtained from Rayleigh and Raman scattering are compared. While both techniques agree nominally, residual effects on the order of 10% remain and will be discussed.

  9. Imaging X-Ray Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Gamboa, E. J.; Kuranz, C. C.; Huntington, C. M.; Trantham, M. R.; Drake, R. P.; Montgomery, D. S.; Benage, J. F.; Letzring, S. A.

    2011-10-01

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering (XRTS) is a powerful technique for measuring these plasma parameters. However, the scattered signal is typically measured with little or no spatial resolution, which limits the ability to diagnose these inhomogeneous plasmas. We report on an experiment at the Omega laser to diagnose a radiation-driven heat wave in a low density carbon foam. The temperature profile is resolved spatially using a new imaging x-ray Thomson scattering diagnostic. Diffraction of scattered x-rays from a toroidally curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile in the target while simultaneously spectrally resolving the scattered radiation. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-FG52-09NA29548, by the National Laser User Facility Program, grant number DE-NA0000850, and by the Los Alamos National Laboratory.

  10. Stray light analysis for the Thomson scattering diagnostic of the ETE Tokamak.

    PubMed

    Berni, L A; Albuquerque, B F C

    2010-12-01

    Thomson scattering is a well-established diagnostic for measuring local electron temperature and density in fusion plasma, but this technique is particularly difficult to implement due to stray light that can easily mask the scattered signal from plasma. To mitigate this problem in the multipoint Thomson scattering system implemented at the ETE (Experimento Tokamak Esférico) a detailed stray light analysis was performed. The diagnostic system was simulated in ZEMAX software and scattering profiles of the mechanical parts were measured in the laboratory in order to have near realistic results. From simulation, it was possible to identify the main points that contribute to the stray signals and changes in the dump were implemented reducing the stray light signals up to 60 times. PMID:21198020

  11. Stray light analysis for the Thomson scattering diagnostic of the ETE Tokamak.

    PubMed

    Berni, L A; Albuquerque, B F C

    2010-12-01

    Thomson scattering is a well-established diagnostic for measuring local electron temperature and density in fusion plasma, but this technique is particularly difficult to implement due to stray light that can easily mask the scattered signal from plasma. To mitigate this problem in the multipoint Thomson scattering system implemented at the ETE (Experimento Tokamak Esférico) a detailed stray light analysis was performed. The diagnostic system was simulated in ZEMAX software and scattering profiles of the mechanical parts were measured in the laboratory in order to have near realistic results. From simulation, it was possible to identify the main points that contribute to the stray signals and changes in the dump were implemented reducing the stray light signals up to 60 times.

  12. Thomson scattering from inertial confinement fusion plasmas

    SciTech Connect

    Glenzer, S.H.; Back, C.A.; Suter, L.J.

    1997-07-08

    Thomson scattering has been developed at the Nova laser facility as a direct and accurate diagnostic to characterize inertial confinement fusion plasmas. Flat disks coated with thin multilayers of gold and beryllium were with one laser beam to produce a two ion species plasma with a controlled amount of both species. Thomson scattering spectra from these plasmas showed two ion acoustic waves belonging to gold and beryllium. The phase velocities of the ion acoustic waves are shown to be a sensitive function of the relative concentrations of the two ion species and are in good agreement with theoretical calculations. These open geometry experiments further show that an accurate measurement of the ion temperature can be derived from the relative damping of the two ion acoustic waves. Subsequent Thomson scattering measurements from methane-filled, ignition-relevant hohlraums apply the theory for two ion species plasmas to obtain the electron and ion temperatures with high accuracy. The experimental data provide a benchmark for two-dimensional hydrodynamic simulations using LASNEX, which is presently in use to predict the performance of future megajoule laser driven hohlraums of the National Ignition Facility (NIF). The data are consistent with modeling using significantly inhibited heat transport at the peak of the drive. Applied to NIF targets, this flux limitation has little effect on x- ray production. The spatial distribution of x-rays is slightly modified but optimal symmetry can be re-established by small changes in power balance or pointing. Furthermore, we find that stagnating plasma regions on the hohlraum axis are well described by the calculations. This result implies that stagnation in gas-filled hohlraums occurs too late to directly affect the capsule implosion in ignition experiments.

  13. MFTF Thomson scattering: a system study

    SciTech Connect

    Frank, A.M.

    1980-09-11

    This report documents the design effort for a Thomson scattering diagnostic system for MFTF. The principal problem is obtaining enough photons, in the presence of a poorly known background, to make satisfactory measurements. No currently available laser will yield enough photons to do this. Design concepts for imaging and detection are discussed. The ability of components to survive in the high-radiation environment of MFTF is identified as an important problem. The transition to MFTF-B makes many of the problems identified here more serious.

  14. Thomson scattering of polarized photons in an intense laser beam

    SciTech Connect

    Byung Yunn

    2006-02-21

    We present a theoretical analysis of the Thomson scattering of linearly and circularly polarized photons from a pulsed laser by electrons. The analytical expression for the photon distribution functions presented in this paper should be useful to designers of Thomson scattering experiments.

  15. Spatial Expansion and Automation of the Pegasus Thomson Scattering Diagnostic System

    NASA Astrophysics Data System (ADS)

    Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Reusch, J. A.; Schlossberg, D. J.; Winz, G. R.

    2015-11-01

    The Pegasus Thomson scattering diagnostic system has recently undergone modifications to increase the spatial range of the diagnostic and automate the Thomson data collection process. Two multichannel spectrometers have been added to the original configuration, providing a total of 24 data channels to view the plasma volume. The new system configuration allows for observation of three distinct regions of the plasma: the local helicity injection (LHI) source (R ~ 67-73.8 cm), the plasma edge (R ~ 51.5-57.6 cm), and the plasma core (R ~ 35-41.1 cm). Each spectrometer utilizes a volume-phase holographic (VPH) grating and a gated-intensified CCD camera. The edge and the LHI spectrometers have been fitted with low-temperature VPH gratings to cover Te = 10 - 100 eV, while the core spectrometer has been fitted with a high-temperature VPH grating to cover Te = 0 . 1 - 1 . 0 keV. The additional spectrometers have been calibrated to account for detector flatness, detector linearity, and vignetting. Operation of the Thomson system has been overhauled to utilize LabVIEW software to synchronize the major components of the Thomson system with the Pegasus shot cycle and to provide intra-shot beam alignment. Multi-point Thomson scattering measurements will be obtained in the aforementioned regions of LHI and Ohmic discharges and will be compared to Langmuir probe measurements. Work supported by US DOE grant DE-FG02-96ER54375.

  16. Tsinghua Thomson scattering X-ray source

    NASA Astrophysics Data System (ADS)

    Tang, Chuanxiang; Huang, Wenhui; Li, Renkai; Du, Yingchao; Yan, Lixin; Shi, Jiaru; Du, Qiang; Yu, Peicheng; Chen, Huaibi; Du, Taibin; Cheng, Cheng; Lin, Yuzheng

    2009-09-01

    We proposed the Tsinghua Thomson scattering X-ray (TTX) source as an ultra-fast, high flux source for advanced X-ray imaging studies and applications. A linac system, which consists of an S-band photocathode RF gun, a SLAC type 3 m traveling wave tube and two X-band structures, generates ultra-short, high brightness electron pulses to scatter with tera-watt femto-second laser pulses. A compact low energy electron storage ring is also designed to dramatically enhance the average X-ray flux. In this paper, we present the simulation studies and optimized parameters of the electron and X-ray pulses. The construction and commissioning status of TTX is also reported.

  17. Signal evaluations using singular value decomposition for Thomson scattering diagnostics

    SciTech Connect

    Tojo, H. Yatsuka, E.; Hatae, T.; Itami, K.; Yamada, I.; Yasuhara, R.; Funaba, H.; Hayashi, H.

    2014-11-15

    This paper provides a novel method for evaluating signal intensities in incoherent Thomson scattering diagnostics. A double-pass Thomson scattering system, where a laser passes through the plasma twice, generates two scattering pulses from the plasma. Evaluations of the signal intensities in the spectrometer are sometimes difficult due to noise and stray light. We apply the singular value decomposition method to Thomson scattering data with strong noise components. Results show that the average accuracy of the measured electron temperature (T{sub e}) is superior to that of temperature obtained using a low-pass filter (<20 MHz) or without any filters.

  18. A compact multichannel spectrometer for Thomson scattering.

    PubMed

    Schoenbeck, N L; Schlossberg, D J; Dowd, A S; Fonck, R J; Winz, G R

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T(e) < 100 eV are achieved by a 2971 l∕mm VPH grating and measurements T(e) > 100 eV by a 2072 l∕mm VPH grating. The spectrometer uses a fast-gated (~2 ns) ICCD camera for detection. A Gen III image intensifier provides ~45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction. PMID:23126988

  19. A compact multichannel spectrometer for Thomson scattering

    SciTech Connect

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-10-15

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of T{sub e} < 100 eV are achieved by a 2971 l/mm VPH grating and measurements T{sub e} > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated ({approx}2 ns) ICCD camera for detection. A Gen III image intensifier provides {approx}45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  20. Implementation of a high throughput spectrograph for Thomson scattering measurements on the Compact Toriodal Hybrid

    NASA Astrophysics Data System (ADS)

    Goforth, Matthew; Traverso, Peter; Maurer, David

    2013-10-01

    To better understand the equilibrium and stability of Compact Toroidal Hybrid (CTH) plasmas, a multipoint Thomson scattering system is under development at Auburn University. Thomson scattering will be performed at 532 nm using a frequency doubled Continuum PL DLS Nd:YAG laser. The Thomson scattered light will be measured using a high throughput HoloSpec f/1.8i imaging spectrograph with in-line interference filter for spectral discrimination of stray laser light. An image intensified charge coupled device (ICCD) camera employing a Gen III photocathode with quantum efficiency of approximately 50% near the frequency doubled laser line is planned as the detection element for the scattered light. Bench and CTH impurity line emission measurements will be presented quantifying spectrometer and ICCD performance and suitability for scattering measurements over the visible spectral region near 532 nm. This work has been supported by US Department of Energy Grant No. DE-FG02-00ER54610 and the Auburn University Undergraduate Research Fellowship Program.

  1. Dense Matter Characterization by X-ray Thomson Scattering

    SciTech Connect

    Landen, O L; Glenzer, S H; Edwards, M J; Lee, R W; Collins, G W; Cauble, R C; Hsing, W W; Hammel, B A

    2000-12-29

    We discuss the extension of the powerful technique of Thomson scattering to the x-ray regime for providing an independent measure of plasma parameters for dense plasmas. By spectrally-resolving the scattering, the coherent (Rayleigh) unshifted scattering component can be separated from the incoherent Thomson component, which is both Compton and Doppler shifted. The free electron density and temperature can then be inferred from the spectral shape of the high frequency Thomson scattering component. In addition, as the plasma temperature is decreased, the electron velocity distribution as measured by incoherent Thomson scattering will make a transition from the traditional Gaussian Boltzmann distribution to a density-dependent parabolic Fermi distribution to. We also present a discussion for a proof-of-principle experiment appropriate for a high energy laser facility.

  2. Upgrades to the MST Thomson scattering diagnostic

    NASA Astrophysics Data System (ADS)

    Kubala, S. Z.; Borchardt, M. T.; den Hartog, D. J.; Holly, D. J.; Jacobson, C. M.; Morton, L. A.; Young, W. C.

    2015-11-01

    The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV to 5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1-25 kHz. A new laser system is being commissioned to enable measurements up to 250 kHz. Other subsystems of the diagnostic are also being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being updated to improve safety, reliability, and maintainablity. Each of the 144 APDs will have an individual rack-mounted switched supply with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) are being added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable electron-velocity measurement. A supercontinuum pulsed white-light source is being implemented to improve spectral calibration of the polychromators. This work is supported by the US DOE and NSF.

  3. Thomson scattering on ELMO Bumpy Torus

    SciTech Connect

    Cobble, J.A.

    1985-04-01

    Below 10/sup 12/ cm/sup -3/ density, a Thomson scattering experiment is an exacting task. Aside from the low signal level, the core plasma in this instance is bathed in high-energy x rays, surrounded by a glowing molecular surface plasma, and heated steady state by microwaves. This means that the noise level from radiation is high and the environment is extremely harsh-so harsh that much effort is required to overcome system damage. In spite of this, the ELMO Bumpy Torus (EBT) system has proven itself capable of providing reliable n/sub e/ and T/sub e/ measurements at densities as low as 2 x 10/sup 11/ cm/sup -3/. Radial scans across 20 cm of the plasma diameter have been obtained on a routine basis, and the resulting information has been a great help in understanding confinement in the EBT plasma. The bulk electron properties are revealed as flat profiles of n/sub e/ and T/sub e/, with density ranging from 0.5 to 2.0 x 10/sup 12/ cm/sup -3/ and temperature decreasing from 100 to 20 eV as pressure in the discharge is increased at constant power. Evidence is presented for a suprathermal tail, which amounts to about 10% of the electron distribution at low pressures. The validity of this conclusion is supported by two independent sensitivity calibrations.

  4. Thomson Scattering at 250 kHz

    NASA Astrophysics Data System (ADS)

    Young, William; den Hartog, D. J.; Morton, L. A.; MST Team

    2015-11-01

    The fast Thomson scattering diagnostic on the MST Reversed-Field Pinch experiment now measures electron temperature at rates of up to 250 kHz, allowing for single shot analysis of phenomena that previously required ensembles of measurements from many shots. Recent laser upgrades include the addition of a second Nd:glass amplifier (giving a total of six amplifiers including four Nd:YAG stages) and optimization of neodymium doping levels within the glass amplifier stages to reduce thermal defocusing. The master-oscillator power-amplifier laser system operates in a pulse-burst mode where the laser generates multiple pulses per flashlamp firing and these bursts of laser pulses are repeated multiple times. When optimizing for the largest number of laser pulses, the laser produces up to 30 pulses at a rate of 100 kHz per burst repeated up to 4 times every 2 ms for a total of 120 temperature measurements per MST discharge. When optimizing for fastest pulsing rate, the laser can produce 8 pulses at 250 kHz within a single burst. A laser system upgrade currently underway is replacement of the diode-pumped pulsed Nd:YVO4 master oscillator with a CW laser chopped by an acoustic-optic modulator; this upgrade may enable pulsing rates faster than 250 kHz. This work is supported by the US DOE and NSF.

  5. Thomson scattering on the Texas Experimental Tokamak

    SciTech Connect

    Porter, J.L. Jr.

    1985-01-01

    A Thomson scattering diagnostic was constructed on the Texas Experimental Tokamak (TEXT) which is capable of measuring local electron temperatures in the range 10 eV less than or equal to T/sub e/ less than or equal to 2000 eV for densities greater than or equal to 5 x 10/sup 12/ cm/sup -3/. This diagnostic has been used to study the edge region of the plasma, the scaling of the central electron temperature and Z/sub effective/ over a wide range of discharge conditions, and the evolution of the electron temperature profile during the plasma formation and during a fast current ramp initiated well into the discharge. Current diffusion was modeled during the current rise portion of the standard TEXT discharge and during discharges in which the plasma current was rapidly increased after a steady-state discharge had been established by using the measured electron temperature profiles as input to a computer code which solves the one dimensional poloidal magnetic field diffusion equation. Because of the large differences found between the predicted and measured values of the loop voltage and the quantity ..beta../sub p/ + 1/sub i//2 during the initial current rise portion of the discharge it is concluded that the plasma current penetrates faster than can be explained by classical resistive current diffusion during this portion of the discharge.

  6. Thomson scattering diagnostic systems in ITER

    NASA Astrophysics Data System (ADS)

    Bassan, M.; Andrew, P.; Kurskiev, G.; Mukhin, E.; Hatae, T.; Vayakis, G.; Yatsuka, E.; Walsh, M.

    2016-01-01

    Thomson scattering (TS) is a proven diagnostic technique that will be implemented in ITER in three independent systems. The Edge TS will measure electron temperature Te and electron density ne profiles at high resolution in the region with r/a>0.8 (with a the minor radius). The Core TS will cover the region r/a<0.85 and shall be able to measure electron temperatures up to 40 keV . The Divertor TS will observe a segment of the divertor plasma more than 700 mm long and is designed to detect Te as low as 0.3 eV . The Edge and Core systems are primary contributors to Te and ne profiles. Both are installed in equatorial port 10 and very close together with the toroidal distance between the two laser beams of less than 600 mm at the first wall (~ 6° toroidal separation), a characteristic that should allow to reliably match the two profiles in the region 0.8

  7. Energy Confinement and Helicity Dissipation Studies Using Thomson Scattering on the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

    Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Schoenbeck, N. L.; Winz, G. R.

    2012-10-01

    The Pegasus Toroidal Experiment provides several unique operating regimes that require characterization of plasma density and temperature by Thomson scattering. High-β, high Ip/ITF regimes at low BT present discharges that require accurate plasma profiles for equilibrium reconstructions. Investigations of non-solenoidal startup using point-source DC helicity injection necessitate characterizing resistive helicity dissipation, accessible via measurement of Te and ne profiles. Furthermore, the usefulness of this method for startup of future fusion devices hinges on confinement scaling during helicity injection. By measuring temperature and density profiles before, during, and after Taylor relaxation, the dominant energy confinement scalings and related helicity dissipation rates for this startup technique can be evaluated. To address these issues, a new multi-point Thomson scattering diagnostic has been deployed on Pegasus. It will provide 12--24 spatial points radially across the plasma with a high degree of flexibility to provide measurements within the varied plasma regimes. First results from the newly installed Thomson scattering system will be shown for some of these regimes.

  8. Dust in FTU with the Thomson Scattering diagnostic

    SciTech Connect

    Giovannozzi, E.; Castaldo, C.; Apruzzese, G.; Maddaluno, G.; Rydzy, A.; Ratynskaia, S.

    2008-09-07

    The Thomson scattering diagnostic has been used to measure the dust present in plasma discharges on FTU tokamak after disruption. The vaporization of the dust particles due to the high power of the laser used by the Thomson scattering diagnostic imply that only a rough estimate of the particle size could be derived from the elastic scattering of the laser light. A simple model for dust particle evaporation has been used to infer the size of the dust particle from the scattered light data.

  9. Thomson Scattering on the HBT-EP Tokamak

    NASA Astrophysics Data System (ADS)

    Levesque, J. P.; Litzner, K. D.; Hanson, J. M.; James, R.; Maurer, D. A.; Mauel, M. E.; Navratil, G. A.; Pedersen, T. S.

    2007-11-01

    Thomson scattering can be used as a non-invasive method for measuring local electron density and temperature in plasmas. We describe the HBT-EP Thomson Scattering diagnostic, which is based on a design in use at DIII-D [1]. A five-channel interference filter polychrometer measures incoherent scattered light from an 8ns, 800mJ, 1064nm Nd:YAG laser pulse. A set of pre-amplification circuits designed by Princeton Scientific Instruments [2] has recently been installed for signal detection using avalanche photodiodes. System layout, alignment, and straylight level reduction techniques will be outlined. Rayleigh and Raman scattering calibration procedures have been used to absolutely calibrate the collection optics and detection system. Recent progress on diagnosing different HBT-EP plasmas using the Thomson scattering diagnostic will be presented. [1] T. N. Carlstrom, et al, Rev. Sci. Instr. 61, 2858, 1990. [2] D. Johnson, et al, Rev. Sci. Instr. 72, 1, 1129, 2001.

  10. Analysis method for Thomson scattering diagnostics in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Ohta, K.; Yoshikawa, M.; Yasuhara, R.; Chikatsu, M.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakasima, Y.; Imai, T.; Ichimura, M.; Yamada, I.; Funaba, H.; Minami, T.

    2016-11-01

    We have developed an analysis method to improve the accuracies of electron temperature measurement by employing a fitting technique for the raw Thomson scattering (TS) signals. Least square fitting of the raw TS signals enabled reduction of the error in the electron temperature measurement. We applied the analysis method to a multi-pass (MP) TS system. Because the interval between the MPTS signals is very short, it is difficult to separately analyze each Thomson scattering signal intensity by using the raw signals. We used the fitting method to obtain the original TS scattering signals from the measured raw MPTS signals to obtain the electron temperatures in each pass.

  11. Molecular origin of background light in Thomson scattering measurements

    SciTech Connect

    McNeill, D.H.

    1986-06-01

    The plasma background light in Thomson scattering measurements is often far higher than expected for a pure hydrogen plasma. The spectral distribution of light from three plasmas (duration: 1 ms to steady state; electron density: below 10/sup 12/ to over 10/sup 14/ cm/sup -3/; temperature: below 20 to over 1000 eV) and signal-to-noise and intensity data from the Thomson scattering systems used on them are compared with analytic estimates to show that in two of these plasmas molecular light dominates the spectrum, while in the other, molecular light is present, but bremsstrahlung is usually more intense. Knowledge of the mechanism for background light can aid in designing detection systems for Thomson scattering and provide information on the neutral species composition and effective charge of the plasma.

  12. LIDAR Thomson scattering for advanced tokamaks. Final report

    SciTech Connect

    Molvik, A.W.; Lerche, R.A.; Nilson, D.G.

    1996-03-18

    The LIDAR Thomson Scattering for Advanced Tokamaks project made a valuable contribution by combining LLNL expertise from the MFE Program: tokamak design and diagnostics, and the ICF Program and Physics Dept.: short-pulse lasers and fast streak cameras. This multidisciplinary group evaluated issues involved in achieving a factor of 20 higher high spatial resolution (to as small as 2-3 mm) from the present state of the art in LIDAR Thomson scattering, and developed conceptual designs to apply LIDAR Thomson scattering to three tokamaks: Upgraded divertor measurements in the existing DIII-D tokamak; Both core and divertor LIDAR Thomson scattering in the proposed (now cancelled) TPX; and core, edge, and divertor LIDAR Thomson scattering on the presently planned International Tokamak Experimental Reactor, ITER. Other issues were evaluated in addition to the time response required for a few millimeter spatial resolution. These include the optimum wavelength, 100 Hz operation of the laser and detectors, minimizing stray light - always the Achilles heel of Thomson scattering, and time dispersion in optics that could prevent good spatial resolution. Innovative features of our work included: custom short pulsed laser concepts to meet specific requirements, use of a prism spectrometer to maintain a constant optical path length for high temporal and spatial resolution, the concept of a laser focus outside the plasma to ionize gas and form an external fiducial to use in locating the plasma edge as well as to spread the laser energy over a large enough area of the inner wall to avoid laser ablation of wall material, an improved concept for cleaning windows between shots by means of laser ablation, and the identification of a new physics issue - nonlinear effects near a laser focus which could perturb the plasma density and temperature that are to be measured.

  13. Applications of phase conjugate mirror to Thomson scattering diagnostics (invited)

    SciTech Connect

    Hatae, T.; Naito, O.; Nakatsuka, M.; Yoshida, H.

    2006-10-15

    A high performance phase conjugate mirror based on stimulated Brillouin scattering (SBS-PCM) has been applied to the Thomson scattering system in the JT-60U tokamak for the first time in order to improve the measurement performance. A SBS-PCM realized a high reflectivity of 95% at a high input power of 145 W (2.9 J, 50 Hz). Using the SBS-PCM, two methods have been developed to increase the intensity of scattered light. For the first method, we have developed a new optical design to provide a double-pass scattering method with the SBS-PCM. A laser beam passing through the plasma is reflected by the SBS-PCM. The reflected beam passes the plasma again along the same path by means of the phase conjugation of the optically nonlinear stimulated Brillouin scattering process. The double-pass Thomson scattering method using the SBS-PCM has demonstrated an increase of the scattered light by a factor of 1.6 compared with the single-pass scattering method in JT-60U. A multipass Thomson scattering method in which the laser beam can be confined between a couple of SBS-PCMs is also proposed. It is estimated that the multipass scattering method generates the scattered light more than several times as large as that of the single-pass scattering method. For the second method, a high-average-power yttrium aluminum garnet (Nd:YAG) laser system has been developed using the SBS-PCM. The SBS-PCM effectively compensated thermal degradation at two amplifier lines, and the average power was increased by a factor of >8 from 45 W (1.5 J, 30 Hz) to 373 W (7.46 J, 50 Hz). A Nd:YAG laser (5 J, 100 Hz) for the edge Thomson scattering in International Thermonuclear Experimental Reactor (ITER) has been designed based on the result.

  14. Warm, Dense Plasma Characterization by X-ray Thomson Scattering

    SciTech Connect

    Landen, O L; Glenzer, S H; Cauble, R C; Lee, R W; Edwards, J E; Degroot, J S

    2000-07-18

    We describe how the powerful technique of spectrally resolved Thomson scattering can be extended to the x-ray regime, for direct measurements of the ionization state, density, temperature, and the microscopic behavior of dense cool plasmas. Such a direct measurement of microscopic parameters of solid density plasmas could eventually be used to properly interpret laboratory measurements of material properties such as thermal and electrical conductivity, EUS and opacity. In addition, x-ray Thomson scattering will provide new information on the characteristics of rarely and hitherto difficult to diagnose Fermi degenerate and strongly coupled plasmas.

  15. Progress of development of Thomson scattering diagnostic system on COMPASS

    SciTech Connect

    Bilkova, P.; Melich, R.; Aftanas, M.; Boehm, P.; Sestak, D.; Jares, D.; Weinzettl, V.; Stoeckel, J.; Hron, M.; Panek, R.; Walsh, M. J.

    2010-10-15

    A new Thomson scattering diagnostic system has been designed and is being built now on the COMPASS tokamak at the Institute of Plasma Physics ASCR in Prague (IPP Prague) in the Czech Republic. This contribution focuses on design, development, and installation of the light collection and detection system. High spatial resolution of 3 mm will be achieved by a combination of design of collection optics and connected polychromators. Imaging characteristics of both core and edge plasma collection objectives are described and fiber backplane design is presented. Several calibration procedures are discussed. The operational deployment of the Thomson scattering diagnostic is planned by the end of 2010.

  16. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid Experiment

    NASA Astrophysics Data System (ADS)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R.

    2014-10-01

    A Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The initial system takes a single point measurement and will be used to assess options for an upgrade to a multi-point system providing electron temperature and density profiles. This single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both ohmically driven, current-carrying plasmas and future gyrotron-heated stellarator plasmas. A principle design goal is to minimize stray laser light, geometrically on the machine side and spectrally on the collection side, to allow measurements of both full and half Thomson scattered spectral profiles. The beam, generated by a frequency doubled Continuum 2 J Nd:YaG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize stray light. Light collection, spectral processing, and signal detection are accomplished with an f / # ~ 1 aspheric lens, a Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. The estimated number of scattered photons per channel will be of the order of 5 ×103 with a signal to noise ratio of S / N = 19 This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  17. Thomson scattering as a method for laser plasma diagnostics

    SciTech Connect

    Alayi, Y.

    1983-12-01

    The Thomson scattering has been used to determine the density and temperature of an inhomogeneous nonstationary plasma. A common method to calibrate the Thomson scattering device consists in replacing the plasma by a gas and measuring the Rayleigh scattering cross section. The angular distribution of the scattered light in Argon is measured, the incident light is a ruby laser with ..delta..t = 30ns and lambda = 6943nm and vertically polarized. We have found that angular distribution is strongly favored in the forward direction (30/sup 0/, 45/sup 0/, 60/sup 0/) and defavored for backward direction (90/sup 0/, 120/sup 0/, 135/sup 0/, 150/sup 0/) in agreement with the results of George, et al, but in disagreement with the Rayleigh theory which assumes a uniform distribution. Our results may be related to the form of the scattered light spectrum which undergoes a dramatic change through the kinetic-hydrodynamic transition. The general form of the spectrum is determined by the parameter y = 1/Kl (where K = 4..pi.. sin (theta/2)/lambda, theta is the scattering angle and l is the free path path), which increases in the direction of the hydrodynamic regime (small angles). By analogy, the Thomson scattering presents the same aspects with ..cap alpha.. = 1/Klambda /SUB D/ (where lambda /SUB D/ is the Debye length). The deviation from the uniform distribution provides the possibility to determine the plasma turbulence spectrum from the scattered light.

  18. Modelling of collective Thomson scattering from collisional plasmas

    NASA Astrophysics Data System (ADS)

    Tierney, T. E., IV; Montgomery, D. S.; Benage, J. F., Jr.; Wysocki, F. J.; Murillo, M. S.

    2003-06-01

    Anomalous broadening of ion-acoustic modes has been observed using collective Thomson scattering from both the electron plasma and ion-acoustic waves in ion-collisional plasmas. Ion-acoustic waves may be broadened by Landau damping, plasma inhomogeneities and instrumental effects. A model was constructed to calculate the contribution of these effects based upon spatially and spectrally resolved measurements of collective Thomson scattering. Collisional broadening effects were then calculated using a modification of the Mermin formalism. The computational model was used to interpret experimental measurements of collisional damping rates in dense, moderately coupled, plasmas. Collisional broadening is weakly dependent of ion-acoustic frequency in nearly isothermal plasmas; and therefore collective Thomson scattering can be used as a measurement technique for collisional damping rates provided all additional broadening mechanisms are taken into account. This paper further demonstrates that modelling of collective Thomson scattering from ion-collisional ion-acoustic modes must account for inhomogeneities, Landau damping, and collisions in order to evaluate plasma parameters, such as temperature and average ionization.

  19. A polarization-based Thomson scattering technique for burning plasmas

    NASA Astrophysics Data System (ADS)

    Parke, E.; Mirnov, V. V.; Den Hartog, D. J.

    2014-02-01

    The traditional Thomson scattering diagnostic is based on measurement of the wavelength spectrum of scattered light, where electron temperature measurements are inferred from thermal broadening of the spectrum. At sufficiently high temperatures, especially those predicted for ITER and other burning plasmas, relativistic effects cause a change in the degree of polarization (P) of the scattered light; for fully polarized incident laser light, the scattered light becomes partially polarized. The resulting reduction of polarization is temperature dependent and has been proposed by other authors as a potential alternative to the traditional spectral decomposition technique. Following the previously developed Stokes vector approach, we analytically calculate the degree of polarization for incoherent Thomson scattering. For the first time, we obtain exact results valid for the full range of incident laser polarization states, scattering angles, and electron temperatures. While previous work focused only on linear polarization, we show that circularly polarized incident light optimizes the degree of depolarization for a wide range of temperatures relevant to burning plasmas. We discuss the feasibility of a polarization based Thomson scattering diagnostic for ITER-like plasmas with both linearly and circularly polarized light and compare to the traditional technique.

  20. Advances in the FTU collective Thomson scattering system

    NASA Astrophysics Data System (ADS)

    Bin, W.; Bruschi, A.; D'Arcangelo, O.; Grosso, G.; Lubiako, L.; Alessi, E.; Castaldo, C.; Centioli, C.; De Angeli, M.; Figini, L.; Galperti, C.; Garavaglia, S.; Granucci, G.; Lontano, M.; Magagnino, S.; Mellera, V.; Minelli, D.; Moro, A.; Muraro, A.; Nardone, A.; Orsitto, F.; Simonetto, A.; Tartari, U.

    2016-11-01

    The new collective Thomson scattering diagnostic installed on the Frascati Tokamak Upgrade device started its first operations in 2014. The ongoing experiments investigate the presence of signals synchronous with rotating tearing mode islands, possibly due to parametric decay processes, and phenomena affecting electron cyclotron beam absorption or scattering measurements. The radiometric system, diagnostic layout, and data acquisition system were improved accordingly. The present status and near-term developments of the diagnostic are presented.

  1. Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration

    SciTech Connect

    Gamboa, E.J.; Huntington, C.M.; Trantham, M.R.; Keiter, P.A; Drake, R.P.; Montgomery, David; Benage, John F.; Letzring, Samuel A.

    2012-05-04

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  2. Detailed characterization of plasma wave behavior using collective Thomson scattering

    SciTech Connect

    Montgomery, D. S.; Kline, J. L.; Tierney, T.

    2004-01-01

    Collective Thomson scattering is widely used to measure bulk plasma parameters in high density, laser-produced plasmas, and is used to detect plasma waves from instabilities. However, inhomogeneity in these small plasmas often leads to a spectrum with insufficient resolution to discern phenomena such as wave damping and nonlinear wave effects. Two techniques are discussed for laser-produced plasmas to overcome these limitations, and provide details of wave damping and nonlinear behavior. First, imaging Thomson scattering is used to obtain spatially-resolved plasma wave profiles in a 100-200 eV plasma, and allows us to infer ion-ion collisional damping rates. Second, a diffraction-limited laser beam is used to drive stimulated Raman scattering (SRS) in a hot plasma, generating large amplitude Langmuir waves. The comparatively small interaction volume permits sufficient spectral resolution to observe nonlinear wave behavior, previously unresolved in other experiments.

  3. Calculation of Thomson scattering spectral fits for interpenetrating flows

    SciTech Connect

    Swadling, G. F. Lebedev, S. V. Burdiak, G. C.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Suzuki-Vidal, F.; Harvey-Thompson, A. J.; Rozmus, W.; Hall, G. N.; Yuan, J.

    2014-12-15

    Collective mode optical Thomson scattering has been used to investigate the interactions of radially convergent ablation flows in Tungsten wire arrays. These experiments were carried out at the Magpie pulsed power facility at Imperial College, London. Analysis of the scattered spectra has provided direct evidence of ablation stream interpenetration on the array axis, and has also revealed a previously unobserved axial deflection of the ablation streams towards the anode as they approach the axis. It is has been suggested that this deflection is caused by the presence of a static magnetic field, advected with the ablation streams, stagnated and accrued around the axis. Analysis of the Thomson scattering spectra involved the calculation and fitting of the multi-component, non-relativistic, Maxwellian spectral density function S (k, ω). The method used to calculate the fits of the data are discussed in detail.

  4. Thomson Scattering Diagnostics in the Plasma of an Ion Thruster

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naoji; Hiraoka, Yoshiaki; Sugita, Kensaku; Kurita, Tomoaki; Tomita, Kentaro; Uchino, Kiichiro; Nakashima, Hideki

    In order to validate the grid erosion evaluation code for the lifetime validation of ion thrusters, the electron number density/temperature in the vicinity of a screen gird in a 30 W class microwave discharge ion thruster were measured by means of laser Thomson scattering (LTS) technique. A photon counting method and a triple grating spectrometer were used against a small Thomson scattering signal and a strong stray laser light. Observed Thomson scattering spectrum tells that the electron energy distribution function was Maxwellian. From this spectrum and the Rayleigh scattering calibration using nitrogen gas, electron number density and electron temperature were calculated to be (3.8±0.2)×1017m-3 and 6.2±0.1 eV, respectively at incident microwave power of 8 W and krypton mass flow rate of 6.2 μg/s. The ion saturation currents estimated from the LTS measurement are in good agreement with ion beam currents through the screen grid for several conditions. These results show that LTS technique is a useful non-intrusive tool for measuring plasma property in the vicinity of the screen grid.

  5. Upgraded divertor Thomson scattering system on DIII-D

    NASA Astrophysics Data System (ADS)

    Glass, F.; Carlstrom, T. N.; Du, D.; McLean, A. G.; Taussig, D. A.; Boivin, R. L.

    2016-11-01

    A design to extend the unique divertor Thomson scattering system on DIII-D to allow measurements of electron temperature and density in high triangularity plasmas is presented. Access to this region is selectable on a shot-by-shot basis by redirecting the laser beam of the existing divertor Thomson system inboard — beneath the lower floor using a moveable, high-damage threshold, in-vacuum mirror — and then redirecting again vertically. The currently measured divertor region remains available with this mirror retracted. Scattered light is collected from viewchords near the divertor floor using in-vacuum, high temperature optical elements and relayed through the port window, before being coupled into optical fiber bundles. At higher elevations from the floor, measurements are made by dynamically re-focusing the existing divertor system collection optics. Nd:YAG laser timing, analysis of the scattered light spectrum via polychromators, data acquisition, and calibration are all handled by existing systems or methods of the current multi-pulse Thomson scattering system. Existing filtered polychromators with 7 spectral channels are employed to provide maximum measurement breadth (Te in the range of 0.5 eV-2 keV, ne in the range of 5 × 1018-1 × 1021 m3) for both low Te in detachment and high Te measurement up beyond the separatrix.

  6. Thomson scattering diagnostic for the measurement of ion species fraction

    SciTech Connect

    Ross, J S; Park, H S; Amendt, A; Divol, L; Kugland, N L; Rozmus, W; Glenzer, S H

    2012-05-01

    Simultaneous Thomson scattering measurements of collective electron-plasma and ion-acoustic fluctuations have been utilized to determine ion species fraction from laser produced CH plasmas. The CH{sub 2} foil is heated with 10 laser beams, 500 J per beam, at the Omega Laser facility. Thomson scattering measurements are made 4 mm from the foil surface using a 30 J 2{omega} probe laser with a 1 ns pulse length. Using a series of target shots the plasma evolution is measured from 2.5 ns to 9 ns after the rise of the heater beams. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the two-ion species theoretical form factor for the ion feature such that the ion temperature, plasma flow velocity and ion species fraction are determined. The ion species fraction is determined to an accuracy of {+-}0.06 in species fraction.

  7. Thomson scattering diagnostic for the measurement of ion species fraction

    SciTech Connect

    Ross, J. S.; Park, H.-S.; Amendt, P.; Divol, L.; Kugland, N. L.; Glenzer, S. H.; Rozmus, W.

    2012-10-15

    Simultaneous Thomson scattering measurements of collective electron-plasma and ion-acoustic fluctuations have been utilized to determine ion species fraction from laser produced CH plasmas. The CH{sub 2} foil is heated with 10 laser beams, 500 J per beam, at the Omega Laser facility. Thomson scattering measurements are made 4 mm from the foil surface using a 30 J 2{omega} probe laser with a 1 ns pulse length. Using a series of target shots the plasma evolution is measured from 2.5 ns to 9 ns after the rise of the heater beams. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the two-ion species theoretical form factor for the ion feature such that the ion temperature, plasma flow velocity and ion species fraction are determined. The ion species fraction is determined to an accuracy of {+-}0.06 in species fraction.

  8. Corotational Tomography of Heliospheric Features Using Global Thomson Scattering Data

    NASA Astrophysics Data System (ADS)

    Jackson, Bernard V.; Hick, P. Paul

    2002-12-01

    The Air Force/NASA Solar Mass Ejection Imager (SMEI) will provide two-dimensional images of the sky in visible light with high (0.1%) photometric precision, and unprecedented sky coverage and cadence. To optimize the information available from these images they must be interpreted in three dimensions. We have developed a Computer Assisted Tomography (CAT) technique that fits a three-dimensional kinematic heliospheric model to remotely-sensed Thomson scattering observations. This technique is designed specifically to determine the corotating background solar wind component from data provided by instruments like SMEI. Here, we present results from this technique applied to the Helios spacecraft photometer observations. The tomography program iterates to a least-squares solution of observed brightnesses using solar rotation, spacecraft motion and solar wind outflow to provide perspective views of each point in space covered by the observations. The corotational tomography described here is essentially the same as used by Jackson et al. (1998) for the analysis of interplanetary scintillation (IPS) observations. While IPS observations are related indirectly to the solar wind density through an assumed (and uncertain) relationship between small-scale density fluctuations and density, Thomson scattering physics is more straightforward, i.e., the observed brightness depends linearly on the solar wind density everywhere in the heliosphere. Consequently, Thomson scattering tomography can use a more direct density-convergence criterion to match observed Helios photometer brightness to brightness calculated from the model density. The general similarities between results based on IPS and Thomson scattering tomography validate both techniques and confirm that both observe the same type of solar wind structures. We show results for Carrington rotation 1653 near solar minimum. We find that longitudinally segmented dense structures corotate with the Sun and emanate from near the

  9. Design and development of the large helical device TV Thomson scattering

    SciTech Connect

    Yamada, I.; Narihara, K.; Funaba, H.; Hayashi, H.

    2004-10-01

    We have developed a television (TV) Thomson scattering and installed it on the large helical device (LHD). The LHD TV Thomson scattering consists of a yttrium-aluminum-garnet (YAG) laser, beam transport system, scattered light collection optics, spectrometer, intensified charge coupled device camera, and data acquisition system. The spatial and temporal resolutions are about 7 mm and a few seconds, respectively. The temporal resolution of the LHD TV Thomson scattering is not good, but will be enough for long-time, steady-state discharge experiments in LHD. In the initial experiments, we measured electron temperature profiles of LHD plasmas at five spatial points. It has been found that the electron temperatures measured by the LHD TV Thomson scattering reasonably agree with those obtained by the LHD YAG Thomson scattering. We will report the details of the LHD TV Thomson scattering system with some experimental data.

  10. Laser Thomson scattering in a pulsed atmospheric arc discharge

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Adams, Steven

    2015-09-01

    Laser scattering measurements, including Rayleigh, Raman, and Thomson scattering have been performed on an atmospheric pulsed arc discharge. Such laser scattering techniques offer a non-invasive diagnostic to measure gas temperature, electron temperature, and electron density in atmospheric plasma sources, particularly those with feature sizes approaching 1 mm. The pulsed discharge is ignited in a pin to pin electrode geometry using a 6 kV pulse with 10 ns duration. The electrodes are housed in a glass vacuum chamber filled with argon gas. The laser signal is produced by a Nd:Yag laser supply, repetitively pulsed at 10 Hz and frequency quadrupled to operate at 266 nm. The scattered laser signal is imaged onto a triple grating spectrometer, which is used to suppress the Rayleigh scatter signal in order to measure the low amplitude Thomson and Raman signals. Preliminary results include measurements of electron temperature and electron density in the plasma column taken during the evolution of the discharge. The laser system is also used to measure the Rayleigh scattering signal, which provides space and time resolved measurements of gas temperature in the arc discharge.

  11. Calibration of the ORNL two-dimensional Thomson scattering system

    SciTech Connect

    Thomas, C.E. Jr.; Lazarus, E.A.; Kindsfather, R.R.; Murakami, M.; Stewart, K.A.

    1985-10-01

    A unified presentation of the calibrations needed for accurate calculation of electron temperature and density from Thomson scattering data for the Oak Ridge National Laboratory two-dimensional Thomson scattering system (SCATPAK II) is made. Techniques are described for measuring the range of wavelengths to which each channel is responsive. A statistical method for calibrating the gain of each channel in the system is given, and methods of checking for internal consistency and accuracy are presented. The relationship between the constants describing the relative light collection efficiency of each channel and plasma light-scattering theory is developed, methods for measuring the channel efficiencies and evaluating their accuracy are described, and the effect on these constants of bending fiber optics is discussed. The use of Rayleigh or Raman scattering for absolute efficiency (density) calibration, stray light measurement, and system efficiency evaluation is discussed; the relative merits of Rayleigh vs Raman scattering are presented; and the relationship among the Rayleigh/Raman calibrations, relative channel efficiency constants, and absolute efficiencies is developed.

  12. Edge profile measurements using Thomson scattering on the KSTAR tokamak.

    PubMed

    Lee, J H; Oh, S; Lee, W R; Ko, W H; Kim, K P; Lee, K D; Jeon, Y M; Yoon, S W; Cho, K W; Narihara, K; Yamada, I; Yasuhara, R; Hatae, T; Yatsuka, E; Ono, T; Hong, J H

    2014-11-01

    In the KSTAR Tokamak, a "Tangential Thomson Scattering" (TTS) diagnostic system has been designed and installed to measure electron density and temperature profiles. In the edge system, TTS has 12 optical fiber bundles to measure the edge profiles with 10-15 mm spatial resolution. These 12 optical fibers and their spatial resolution are not enough to measure the pedestal width with a high accuracy but allow observations of L-H transition or H-L transitions at the edge. For these measurements, the prototype ITER edge Thomson Nd:YAG laser system manufactured by JAEA in Japan is installed. In this paper, the KSTAR TTS system is briefly described and some TTS edge profiles are presented and compared against the KSTAR Charge Exchange Spectroscopy and other diagnostics. The future upgrade plan of the system is also discussed in this paper.

  13. Dual-angle, self-calibrating Thomson scattering measurements in RFX-MOD

    SciTech Connect

    Giudicotti, L.

    2014-11-15

    In the multipoint Thomson scattering (TS) system of the RFX-MOD experiment the signals from a few spatial positions can be observed simultaneously under two different scattering angles. In addition the detection system uses optical multiplexing by signal delays in fiber optic cables of different length so that the two sets of TS signals can be observed by the same polychromator. Owing to the dependence of the TS spectrum on the scattering angle, it was then possible to implement self-calibrating TS measurements in which the electron temperature T{sub e}, the electron density n{sub e} and the relative calibration coefficients of spectral channels sensitivity C{sub i} were simultaneously determined by a suitable analysis of the two sets of TS data collected at the two angles. The analysis has shown that, in spite of the small difference in the spectra obtained at the two angles, reliable values of the relative calibration coefficients can be determined by the analysis of good S/N dual‑angle spectra recorded in a few tens of plasma shots. This analysis suggests that in RFX-MOD the calibration of the entire set of TS polychromators by means of the similar, dual-laser (Nd:YAG/Nd:YLF) TS technique, should be feasible.

  14. Dual-angle, self-calibrating Thomson scattering measurements in RFX-MOD

    NASA Astrophysics Data System (ADS)

    Giudicotti, L.; Pasqualotto, R.; Fassina, A.

    2014-11-01

    In the multipoint Thomson scattering (TS) system of the RFX-MOD experiment the signals from a few spatial positions can be observed simultaneously under two different scattering angles. In addition the detection system uses optical multiplexing by signal delays in fiber optic cables of different length so that the two sets of TS signals can be observed by the same polychromator. Owing to the dependence of the TS spectrum on the scattering angle, it was then possible to implement self-calibrating TS measurements in which the electron temperature Te, the electron density ne and the relative calibration coefficients of spectral channels sensitivity Ci were simultaneously determined by a suitable analysis of the two sets of TS data collected at the two angles. The analysis has shown that, in spite of the small difference in the spectra obtained at the two angles, reliable values of the relative calibration coefficients can be determined by the analysis of good S/N dual-angle spectra recorded in a few tens of plasma shots. This analysis suggests that in RFX-MOD the calibration of the entire set of TS polychromators by means of the similar, dual-laser (Nd:YAG/Nd:YLF) TS technique, should be feasible.

  15. A reflective optical transport system for ultraviolet Thomson scattering from electron plasma waves on OMEGA

    SciTech Connect

    Katz, J.; Boni, R.; Sorce, C.; Follett, R.; Shoup, M. J. III; Froula, D. H.

    2012-10-15

    A reflective optical transport system has been designed for the OMEGA Thomson-scattering diagnostic. A Schwarzschild objective that uses two concentric spherical mirrors coupled to a Pfund objective provides diffraction-limited imaging across all reflected wavelengths. This enables the operator to perform Thomson-scattering measurements of ultraviolet (0.263 {mu}m) light scattered from electron plasma waves.

  16. Cavity Enhanced Thomson Scattering for Low Temperature Plasmas

    NASA Astrophysics Data System (ADS)

    Yalin, Azer; Friss, Adam; Lee, Brian; Franka, Isaiah

    2013-09-01

    This contribution describes the design, simulation, and initial experimental development of a novel laser Thomson scattering (LTS) system for measurement of weakly-ionized low temperature plasmas. The LTS approach uses a high power intra-cavity beam of power ~10-100 kW to provide increased scattered photon counts and sensitivity as compared to conventional LTS experiments that use light sources with orders of magnitude lower average power. The high power intra-cavity beam is generated by locking a narrow linewidth source laser to a high-finesse optical cavity via Pound-Drever-Hall locking. The plasma (to be studied) is housed with the high-finesse optical cavity. The high-power source is combined with a detection system comprised of a high-suppression triple monochromator and a low-noise photomultiplier tube used in photon counting mode. We present simulations of signal strengths and scattering spectra including elastic scatter background, detector dark counts, and random (counting) noise contributions. Expected experimental performance is assessed from fits to the simulated data. The number density and electron temperature of a 1010 cm-3 plasma should be accurately measurable with standard deviation of <5% in a measurement time of 5 minutes per wavelength channel. We also present experimental development including characterization of laser locking, and initial Rayleigh and Raman signals which will be used to calibrate the Thomson system.

  17. Exact relativistic expressions for polarization of incoherent Thomson scattering

    NASA Astrophysics Data System (ADS)

    Mirnov, V. V.; Den Hartog, D. J.; Parke, E.

    2016-05-01

    We present a derivation of the degree of polarization for incoherent Thomson scattering (TS) using Mueller matrix formalism. An exact analytic solution is obtained for spectrum-integrated matrix elements. The solution is valid for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. It is based on a newly developed theoretical model, a finite transit time (FTT) correction to previous theoretical work on TS polarization. The Mueller matrix elements are substantially different from previous calculations without the FTT correction, even to the lowest linear order in Te/mec2≪1 . Mathematically, the derivation is a unique example of fully analytical integration of the 3D scattering operator over a relativistic Maxwellian distribution function; experimentally, the results have application to the use of the polarization properties of Thomson scattered light as a method of electron temperature measurement. The results can also be used as a reliable tool for benchmarking and verification of numerical codes for frequency resolved properties of TS polarization.

  18. Development of prototype polychromator system for KSTAR Thomson scattering diagnostic

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Lee, S. H.; Son, S. H.; Ko, W. H.; Seo, D. C.; Yamada, I.; Her, K. H.; Jeon, J. S.; Bog, M. G.

    2015-12-01

    A polychromator is widely used by the Thomson scattering system for measuring the electron temperature and density. This type of spectrometer includes optic elements such as band-pass filters, focusing lens, collimating lens, and avalanche photodiodes (APDs). The characteristics of band-pass filters in the polychromator are determined by the measuring range of the Thomson system. KSTAR edge polychromators were developed by co-works at NIFS in Japan, and the KSTAR core polychromators were developed by NFRI in Korea. The power supply system of these polychromators is connected only to one power supply module and can manually control the APD's voltage at the front side of the power supply by using a potentiometer. In this paper, a prototype polychromator is introduced at the KSTAR. The prototype polychromator system has a built-in power supply unit that includes high voltage for the APD and ± 5 V for an op-amp IC. The high voltage for the APD is finely controlled and monitored using a PC with the LabView software. One out of the six band pass-filters has a center wavelength of 523.5 nm with 2-nm bandwidth, which can measure Zeff, and the other five band-pass filters can simultaneously measure the Thomson signal. In addition, we will show the test result of this prototype polychromator system during the KSTAR experiment campaign (2015).

  19. Laser scattering on an atmospheric pressure plasma jet: disentangling Rayleigh, Raman and Thomson scattering

    NASA Astrophysics Data System (ADS)

    van Gessel, A. F. H.; Carbone, E. A. D.; Bruggeman, P. J.; van der Mullen, J. J. A. M.

    2012-02-01

    Laser scattering provides a very direct method for measuring the local densities and temperatures inside a plasma. We present new experimental results of laser scattering on an argon atmospheric pressure microwave plasma jet operating in an air environment. The plasma is very small so a high spatial resolution is required to study the effect of the penetration of air molecules into the plasma. The scattering signal has three overlapping contributions: Rayleigh scattering from heavy particles, Thomson scattering from free electrons and Raman scattering from molecules. The Rayleigh scattering signal is filtered out optically with a triple grating spectrometer. The disentanglement of the Thomson and Raman signals is done with a newly designed fitting method. With a single measurement we determine profiles of the electron temperature, electron density, gas temperature, partial air pressure and the N2/O2 ratio, with a spatial resolution of 50 µm, and including absolute calibration.

  20. Multichannel Thomson scattering systems with high spatial resolution (invited)

    SciTech Connect

    Johnson, D.; Bretz, N.; Dimock, D.; Grek, B.; Long, D.; Palladino, R.; Tolnas, E.

    1986-08-01

    Thomson scattering systems capable of providing snapshot profiles of electron temperature and density with high spatial resolution (>50 points) have become routine diagnostics on the Princeton large torus (PLT), Princeton divertor experiment (PDX), and tokamak fusion test reactor (TFTR) tokamaks. The design parameters of these systems are compared. Particular attention is given to describing those new components and techniques which have contributed most to improved data quality and reliability in the ten-year evolution of these systems. Examples of recent TFTR T-italic/sub e-italic/(R-italic) and n-italic/sub e-italic/(R-italic) profiles are presented.

  1. Multichannel Thomson scattering systems with high spatial resolution (invited)

    NASA Astrophysics Data System (ADS)

    Johnson, D.; Bretz, N.; Dimock, D.; Grek, B.; Long, D.; Palladino, R.; Tolnas, E.

    1986-08-01

    Thomson scattering systems capable of providing snapshot profiles of electron temperature and density with high spatial resolution (>50 points) have become routine diagnostics on the Princeton large torus (PLT), Princeton divertor experiment (PDX), and tokamak fusion test reactor (TFTR) tokamaks. The design parameters of these systems are compared. Particular attention is given to describing those new components and techniques which have contributed most to improved data quality and reliability in the ten-year evolution of these systems. Examples of recent TFTR Te(R) and ne(R) profiles are presented.

  2. Polychromator for the edge Thomson scattering system in ITER.

    PubMed

    Yatsuka, E; Hatae, T; Fujie, D; Kurokawa, A; Kusama, Y

    2012-10-01

    A new type polychromator has been designed for the edge Thomson scattering system in ITER. Signal light is parallelly dispersed into two parts at the first interference filter. Spectral transmissivities for some spectral channels may enhance better than the conventional type polychromator. In the new type polychromator, the misalignment due to the machine accuracy is expected to be within the margin of APD area. In order to calibrate the spectral transmissivity using the dual-laser injection method during the plasma discharge, it is preferred that the spectral channels are separated at the geometric mean of the injected two wavelengths.

  3. Laser beam combiner for Thomson scattering core LIDAR.

    PubMed

    Balboa, I; Huang, B; Naylor, G; Walsh, M; Sirinelli, A; Parsons, P; Fessey, J; Townsend, M; Beurskens, M; Conway, N; Flanagan, J; Kempenaars, M; Kirk, A

    2010-10-01

    The light detection and ranging Thomson scattering (TS) diagnostic is advantageous since it only requires a single view port into the tokamak. This technique requires a short pulse laser at high energy, usually showing a limited repetition rate. Having multiple lasers will increase the repetition rate. This paper presents a scanning mirror as a laser beam combiner. Measurements of the position accuracy and jitter show that the pointing stability of the laser beam is within ±25 μrad for over tens of seconds. A control feedback loop is implemented to demonstrate the long term stability. Such a system could be applied for ITER and JET. PMID:21033888

  4. Thomson scattering in magnetic fields. [of white dwarf stars

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara

    1989-01-01

    The equation of transfer in Thomson scattering atmospheres with magnetic fields is solved using Monte Carlo methods. Two cases, a plane parallel atmosphere with a magnetic field perpendicular to the atmosphere, and a dipole star, are investigated. The wavelength dependence of polarization from plane-parallel atmosphere is qualitatively similar to that observed in the magnetic white dwarf Grw+70 deg 8247, and the field strength determined by the calculation, 320 MG, is quantitatively similar to that determined from the line spectrum. The dipole model does not resemble the data as well as the single plane-parallel atmosphere.

  5. Imaging Thomson scattering measurements of radiatively heated Xe

    SciTech Connect

    Pollock, B; Meinecke, J; Kuschel, S; Ross, J S; Divol, L; Glenzer, S H; Tynan, G R

    2012-05-01

    Uniform density and temperature Xe plasmas have been produced over >4 mm scale-lengths using x-rays generated in a cylindrical Pb cavity. The cavity is 750 {micro}m in depth and diameter, and is heated by a 300 J, 2 ns square, 1054 nm laser pulse focused to a spot size of 200 {micro}m at the cavity entrance. The plasma is characterized by simultaneous imaging Thomson scattering measurements from both the electron and ion scattering features. The electron feature measurement determines the spatial electron density and temperature profile, and using these parameters as constraints in the ion feature analysis allows an accurate determination of the charge state of the Xe ions. The Thomson scattering probe beam is 40 J, 200 ps, and 527 nm, and is focused to a 100 {micro}m spot size at the entrance of the Pb cavity. Each system has a spatial resolution of 25 {micro}m, a temporal resolution of 200 ps (as determined by the probe duration), and a spectral resolution of 2 nm for the electron feature system and 0.025 nm for the ion feature system. The experiment is performed in a Xe filled target chamber at a neutral pressure of 3-10 Torr, and the x-rays produced in the Pb ionize and heat the Xe to a charge state of 20 {+-} 4 at up to 200 eV electron temperatures.

  6. Analysis of Thomson scattered light from an arc plasma jet.

    PubMed

    Gregori, G; Kortshagen, U; Heberlein, J; Pfender, E

    2002-04-01

    In this paper we present an analysis of Thomson scattered light from an arc plasma jet. Our approach goes beyond the standard random-phase approximation (RPA) and provides more consistent data for the electron temperature and density in plasmas that are weakly nonideal and collisional. The theory is based on a memory function formalism for the spectral density function with the use of the three lowest-order frequency-moment sum rules. These moments are then corrected for temperature inhomogeneities in the scattering volume. The proposed interpretation of scattering data is compared with the RPA result and with the standard Bhatnagar-Gross-Krook collisional model for the dynamic structure factor. It is shown that the obtained electron temperature values are closer but not equal to local thermodynamic equilibrium temperature values extracted from spectroscopic measurements.

  7. Horizontal Thomson Scattering Systems for DIII-D and SSPX

    SciTech Connect

    Nilson, D.G.; Hill, D.N.; Wood, R.D.; McClean, H.; Moeller, J.M.; Labik, G.; Carlstron, T.N.; Bray, B.; Hsieh, C.L.

    1999-08-01

    DIII-D--Three of the seven existing core Thomson scattering laser beams were redirected to probe the previously unmeasured central region of the DIII-D plasma. Modifications to the existing collection optics system and support tower were made to inject the lasers and collect scattered light in this new extended region. Stray light levels were reduced to acceptable levels to permit Rayleigh scattering calibration on five of the six new channels, indicating that the new in-vessel dump operates well. Measurements of the plasma temperature and density from the plasma edge to the center are now possible. Peaked density profiles are now observed in this new measurement region. SSPX--We have completed the design and installation of a 10-spatial channel Thomson scattering system to measure the plasma temperature and density profile on SSPX. A single-pulsed YAG laser operating at 0.7 J and 8 ns is used to scatter photons into a 7-element collection optic that provides a spatial resolution of 1.5 cm at the outer plasma edge and 7.5 cm at the inner edge of a .5 m radius spheromak plasma. The collected light is then analyzed by a 4-channel interference filtered polychromator which has been optimized to measure temperatures between 2 eV and 2 keV and densities as low as 1 x 10{sup 12} cm{sup 3}. We use an in-vessel beam dump and a series of entrance and exit baffles to reduce the stray laser light and provide for an absolute density calibration by Rayleigh scattering in argon gas.

  8. Thomson scattering on non-equilibrium low density plasmas: principles, practice and challenges

    NASA Astrophysics Data System (ADS)

    Carbone, Emile; Nijdam, Sander

    2015-01-01

    In this paper, we review the main challenges related to laser Thomson scattering on low temperature plasmas. The main features of the triple grating spectrometer used to discriminate Thomson and Raman scattering signals from Rayleigh scattering and stray light are presented. The main parameters influencing the detection limit of Thomson scattering are reviewed. Laser stray light and plasma emission are two limiting factors, but Raman scattering from molecules inside the plasma will further decrease it. In the case of non-thermal plasmas at high pressure, Thomson scattering is the only technique which allows us to obtain the electron density without any prior knowledge of the plasma properties. Moreover, very high 3D spatial and temporal resolutions can easily be achieved. However, special care still needs to be taken to verify that Thomson scattering is non intrusive. The mechanisms that will lead to possible measurement errors are discussed. The wavelength-resolved scattering signal also allows us to get direct information about the electron energy distribution function in the case of incoherent light scattering. Finally, we discuss some recent applications of Thomson scattering on atmospheric pressure plasma jets, but also in the field of electron collision kinetics. Thomson scattering can be applied on atomic but also molecular plasmas. In the latter case, one needs to take into account the possible contribution of rotational Raman scattering.

  9. Design of Thomson scattering diagnostic system on J-TEXT

    NASA Astrophysics Data System (ADS)

    Zhou, Yinan; Gao, Li; Huang, Jiefeng; Qiu, Qingshuang; Zhuang, Ge

    2016-11-01

    An infrared multi-channel Thomson scattering diagnostic system is designed from the viewpoint of development of the proposed system on the Joint Texas Experimental Tokamak (J-TEXT). A 3 J/50 Hz Nd:YAG laser, which is injected vertically into plasma in the direction from top to bottom, serves as the power source of the system. The scattering light is then collected horizontally and is transmitted to an interference-filter avalanche photodiode based polychromater for spectrum analysis. The system covers the half plasma cross section, providing 14 spatial points with 2 cm resolution. The proposed system can thus satisfy the requirements of the J-TEXT at present and in the near future. A detailed description of the system design is presented in this paper.

  10. The Thomson scattering system at Wendelstein 7-X

    NASA Astrophysics Data System (ADS)

    Pasch, E.; Beurskens, M. N. A.; Bozhenkov, S. A.; Fuchert, G.; Knauer, J.; Wolf, R. C.

    2016-11-01

    This paper describes the design of the Thomson scattering system at the Wendelstein 7-X stellarator. For the first operation campaign we installed a 10 spatial channel system to cover a radial half profile of the plasma cross section. The start-up system is based on one Nd:YAG laser with 10 Hz repetition frequency, one observation optics, five fiber bundles with one delay line each, and five interference filter polychromators with five spectral channels and silicon avalanche diodes as detectors. High dynamic range analog to digital converters with 14 bit, 1 GS/s are used to digitize the signals. The spectral calibration of the system was done using a pulsed super continuum laser together with a monochromator. For density calibration we used Raman scattering in nitrogen gas. Peaked temperature profiles and flat density profiles are observed in helium and hydrogen discharges.

  11. TFTR 60 GHz alpha particle collective Thomson Scattering diagnostic

    SciTech Connect

    Machuzak, J.S.; Woskov, P.P.; Gilmore, J.; Bretz, N.L.; Park, H.K.; Aamodt, R.E.; Cheung, P.Y.; Russell, D.A.; Bindslev, H.

    1995-03-01

    A 60 GHz gyrotron collective Thomson Scattering alpha particle diagnostic has been implemented for the D-T period on TFM. Gyrotron power of 0.1-1 kW in pulses of up to 1 second can be launched in X-mode. Efficient corrugated waveguides are used with antennaes and vacuum windows of the TFTR Microwave Scattering system. A multichannel synchronous detector receiver system and spectrum analyzer acquire the scattered signals. A 200 Megasample/sec digitizer is used to resolve fine structure in the frequency spectrum. By scattering nearly perpendicular to the magnetic field, this experiment will take advantage of an enhancement of the scattered signal which results from the interaction of the alpha particles with plasma resonances in the lower hybrid frequency range. Significant enhancements are expected, which will make these measurements possible with gyrotron power less than 1 kW, while maintaining an acceptable signal to noise ratio. We hope to extract alpha particle density and velocity distribution functions from the data. The D and T fuel densities and temperatures may also be obtainable by measurement of the respective ion cyclotron harmonic frequencies.

  12. Stokes parameters for Thomson scattering in a strong magnetic field with radiation damping

    NASA Astrophysics Data System (ADS)

    Chou, Chih-Kang; Chen, Hui-Hwa

    1990-12-01

    The effect of a strong magnetic field on Thomson scattering is investigated taking into account radiation damping by using the Abraham-Lorentz equation instead of the Newton-Lorentz equation. The Stokes parameters for Thomson scattering are computed in terms of the state of polarization of the incident wave, the electron-cyclotron frequency, the angle of incidence, and the angle of scattering. It is noted that the Stokes parameters for the scattered radiation show resonance structures.

  13. The Thomson Scattering System on the Lithium Tokamak eXperiment (LTX)

    SciTech Connect

    T. Strickler, R. Majeski, R. Kaita, B. LeBlanc

    2008-07-31

    The Lithium Tokamak eXperiment (LTX) is a spherical tokamak with R0 = 0.4m, a = 0.26m, BTF ~ 3.4kG, IP ~ 400kA, and pulse length ~ 0.25s. The goal of LTX is to investigate tokamak plasmas that are almost entirely surrounded by a lithium-coated plasma-facing shell conformal to the last closed magnetic flux surface. Based on previous experimental results and simulation, it is expected that the low-recycling liquid lithium surfaces will result in higher temperatures at the plasma edge, flatter overall temperature profiles, centrally-peaked density profiles, and an increased confinement time. To test these predictions, the electron temperature and density profiles in LTX will be measured by a multi-point Thomson scattering system (TVTS). Initially, TS measurements will be made at up to 12 simultaneous points between the plasma center and plasma edge. Later, high resolution edge measurements will be deployed to study the lithium edge physics in greater detail. Technical challenges to implementing the TS system included limited "line of sight" access to the plasma due to the plasma-facing shell and problems associated with the presence of liquid lithium.

  14. Progress of microwave collective Thomson scattering in LHD

    NASA Astrophysics Data System (ADS)

    Tanaka, K.; Nishiura, M.; Kubo, S.; Shimozuma, T.; Saito, T.

    2015-12-01

    Microwave collective Thomson scattering (CTS) by using a 77 GHz gyrotron is routinely working in LHD and the improvements of the system is now underway. The targets of this diagnostic are measurements of energetic fast ion distribution and ion ratio. In the present system, 800kW 77 GHz gyrotron is injected horizontally and scattered radiation is received changing scattering angle. The system works with existence of electron cyclotron resonance layer. Thus, most of the power is absorbed at the layer like beam damping and stray radiation dramatically decreases. Gyrotron is modulated at 40 Hz, then, background ECE, which is signal in gyrotron off phase, is subtracted from scattered signal in gyrotron on phase. The perturbation of electron temperature due to the gyrotron injection is almost negligible. Temporal evolution of CTS spectrum is obtained by 32ch filter bank receiver through discharge and fine spectrum is obtained by 10 GHz sampling fast digitizer for 80 ms. Change of the width and asymmetry of CTS spectrum is observed after turning off of tangentially injected neutral beam (NB). This is qualitatively consistent with reduction of fast ion density. Preliminary data of ion ratio between hydrogen and helium are also obtained.

  15. High resolution Thomson scattering for Joint European Torus (JET)

    SciTech Connect

    Pasqualotto, R.; Nielsen, P.; Gowers, C.; Beurskens, M.; Kempenaars, M.; Carlstrom, T.; Johnson, D.

    2004-10-01

    A Thomson scattering system is being developed for Joint European Torus with 15 mm spatial resolution and a foreseen accuracy for temperature better than 15% at a density of 10{sup 19} m{sup -3}. This resolution is required at the internal transport barrier and edge pedestal and it can not be fully achieved with the present light detection and ranging systems. The laser for this system is Nd:YAG, 5 Joule, 20 Hz. Scattering volumes from R=2.9 m to R=3.9 m are imaged onto 1 mm diameter fibers, with F/25 collection aperture. Two fibers are used per scattering volume. Using optical delay lines, three scattering volumes are combined in each of the 21 filter polychromators. The signals are recorded with transient digitizers, which allow the combined time delayed signals to be resolved. Knowledge of the time delay between signals allows the use of correlation techniques in determining signal levels. The ac output of the amplifier is used, which tolerates a higher level of background signal without affecting dynamic range. The noise resulting from plasma light is determined directly.

  16. Multiposition Multipass Thomson Scattering Diagnostic for Tokamak NOVA-UNICAMP

    NASA Astrophysics Data System (ADS)

    Monteiro, Marcelo J. R.; Machida, Munemasa

    2005-01-01

    In this article, the use of an 8× 8-matrix independent 10-stage dynode multichannel photomultiplier for multipass Thomson scattering is described. Light from a pulsed ruby laser is irradiated 12 times in the central region of plasma using the resonator cavity of a multipass system, and integrated scattered light is detected for the first time using the multichannel photomultiplier XP1752 from Philips. The simultaneous measurements of electron temperature and density at four spatial positions, which can be extended by increasing the numbers of Analog-to-Digital Converter (ADC) channels and signal output windows, have been performed throughout full discharge by a shot-to-shot procedure. An electron temperature Te of 50 eV and a density ne of 5× 1012 cm-3 were measured for the tokamak NOVA-UNICAMP. Because of the use of a low-power ruby laser (typically 1 J) and scattered light amplification using a multipass system, the level of stray light was kept low and absolute density measurements were made possible by nitrogen Rayleigh scattering.

  17. Design of multipulse Thomson scattering diagnostic for SST-1 tokamak

    NASA Astrophysics Data System (ADS)

    Kumar, Ajai; Chavda, Chhaya; Saxena, Y. C.; Singh, Ranjeet; Thakar, Aruna; Thomas, Jinto; Patel, Kiran; Pandya, Kaushal; Bedakihale, Vijay

    2007-04-01

    A multipulse Nd:YAG (Yttrium aluminum garnet) Thomson scattering (TS) system is designed and developed for measuring electron temperature (Te) and density (ne) profiles of SST-1 tokamak. The system operates at vertical, divertor, and horizontal (midplane) regions of plasma and measures the electron temperature of 20eVto1.5keV and density of 1018-1019m-3. Six Nd:YAG lasers synchronized with external control is used to get three different temporal resolutions (30Hz, 180Hz, and 1kHz). The entire system is laboratory tested for the stability of alignment and performance over a distance of 30m. Different imaging lens assemblies are designed to image the scattered photons from each of the scattering region to an array of optical fibers. A low cost and compact five-channel interference filter polychromator is designed, fabricated, and tested for its image quality and the filter transmission characteristics. Detection system with an avalanche photodiode and required signal conditioning electronics is developed for detecting the scattered photons. A data acquisition and control module operating on PXI bus is developed for the real time data acquisition and system control. A detailed description of design and testing of TS subsystems is presented in this article.

  18. Thomson scattering in high-intensity chirped laser pulses

    SciTech Connect

    Holkundkar, Amol R.; Harvey, Chris Marklund, Mattias

    2015-10-15

    We consider the Thomson scattering of an electron in an ultra-intense laser pulse. It is well known that at high laser intensities, the frequency and brilliance of the emitted radiation will be greatly reduced due to the electron losing energy before it reaches the peak field. In this work, we investigate the use of a small frequency chirp in the laser pulse in order to mitigate this effect of radiation reaction. It is found that the introduction of a negative chirp means the electron enters a high frequency region of the field while it still has a large proportion of its original energy. This results in a significant enhancement of the frequency and intensity of the emitted radiation as compared to the case without chirping.

  19. Design and Calibration of Thomson Scattering Diagnostic for TCSU

    NASA Astrophysics Data System (ADS)

    Lee, K. Y.; Golingo, R. P.

    2009-11-01

    A single pulse ruby laser Thomson scattering system is being designed and installed to measure the electron temperature Te and density ne profiles in a Rotating Magnetic Field (RMF) driven FRC plasma. Based on measurements that show the total temperature is about 150 eV and the density is about 10^19 m-3 in the Translation, Confinement and Sustainment Upgrade (TCSU) experiment, a Te of about 100 eV is expected. The system allows observation of 5 points on the bottom half section of the 40 cm radius TCSU device. Each spatial point is resolved with a GA polychromator attached to three PPPL pre-amplifier modules. A model to relate the fast and slow channel of the pre-amplifier followed by a spectral calibration of the polychromator characterizing the transmission of the bandpass interference filters is described. The overall system design will be discussed and initial results may be presented.

  20. Thomson scattering diagnostic upgrade on DIII-D

    SciTech Connect

    Ponce-Marquez, D. M.; Bray, B. D.; Deterly, T. M.; Liu, C.; Eldon, D.

    2010-10-15

    The DIII-D Thomson scattering system has been upgraded. A new data acquisition hardware was installed, adding the capacity for additional spatial channels and longer acquisition times for temperature and density measurements. Detector modules were replaced with faster transimpedance circuitry, increasing the signal-to-noise ratio by a factor of 2. This allows for future expansion to the edge system. A second phase upgrade scheduled for 2010-2011 includes the installation of four 1 J/pulse Nd:YAG lasers at 50 Hz repetition rate. This paper presents the first completed phase of the upgrade and performance comparison between the original system and the upgraded system. The plan for the second phase is also presented.

  1. Calibration of a Thomson scattering diagnostic for fluctuation measurements

    SciTech Connect

    Stephens, H. D.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Holly, D. J.; O'Connell, R.; Reusch, J. A.

    2008-10-15

    Detailed calibrations of the Madison Symmetric Torus polychromator Thomson scattering system have been made suitable for electron temperature fluctuation measurements. All calibrations have taken place focusing on accuracy, ease of use and repeatability, and in situ measurements wherever possible. Novel calibration processes have been made possible with an insertable integrating sphere (ISIS), using an avalanche photodiode (APD) as a reference detector and optical parametric oscillator (OPO). Discussed are a novel in situ spatial calibration with the use of the ISIS, the use of an APD as a reference detector to streamline the APD calibration process, a standard dc spectral calibration, and in situ pulsed spectral calibration made possible with a combination of an OPO as a light source, the ISIS, and an APD used as a reference detector. In addition a relative quantum efficiency curve for the APDs is obtained to aid in uncertainty analysis.

  2. Performance of JT-60SA divertor Thomson scattering diagnostics

    SciTech Connect

    Kajita, Shin; Hatae, Takaki; Tojo, Hiroshi; Hamano, Takashi; Shimizu, Katsuhiro; Kawashima, Hisato; Enokuchi, Akito

    2015-08-15

    For the satellite tokamak JT-60 Super Advanced (JT-60SA), a divertor Thomson scattering measurement system is planning to be installed. In this study, we improved the design of the collection optics based on the previous one, in which it was found that the solid angle of the collection optics became very small, mainly because of poor accessibility to the measurement region. By improvement, the solid angle was increased by up to approximately five times. To accurately assess the measurement performance, background noise was assessed using the plasma parameters in two typical discharges in JT-60SA calculated from the SONIC code. Moreover, the influence of the reflection of bremsstrahlung radiation by the wall is simulated by using a ray tracing simulation. The errors in the temperature and the density are assessed based on the simulation results for three typical field of views.

  3. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    NASA Astrophysics Data System (ADS)

    Follett, R. K.; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H.

    2016-11-01

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 1021 cm-3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  4. Progress on Thomson scattering in the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

    Schlossberg, D. J.; Bongard, M. W.; Fonck, R. J.; Schoenbeck, N. L.; Winz, G. R.

    2013-11-01

    A novel Thomson scattering system has been implemented on the Pegasus Toroidal Experiment where typical densities of 1019 m-3 and electron temperatures of 10 to 500 eV are expected. The system leverages technological advances in high-energy pulsed lasers, volume phase holographic (VPH) diffraction gratings, and gated image intensified (ICCD) cameras to provide a relatively low-maintenance, economical, robust diagnostic system. Scattering is induced by a frequency-doubled, Q-switched Nd:YAG laser (2 J at 532 nm, 7 ns FWHM pulse) directed to the plasma over a 7.7 m long beam path, and focused to < 3 mm throughout the collection region. Inter-shot beam alignment is adjustable with less than a 0.01 mm spatial resolution in the collection region. A custom lens system collects scattered photons at radii 15 cm to 85 cm from the machine's center, at ~ F/6 with 14 mm radial resolution. The initial configuration provides scattering measurements at 12 spatial locations and 12 simultaneous background measurements at adjacent locations. If plasma background subtraction proves to be insignificant, these background channels will be used as viewing channels. Each spectrometer supports 8 spatial channels and can provide 8 or more spectral bins each. The spectrometers use high-efficiency VPH transmission gratings (eff. > 80%) and fast-gated ICCDs (gate > 2 ns, Gen III intensifier) with high-throughput (F/1.8), achromatic lensing. A stray light mitigation facility has been implemented, consisting of a multi-aperture optical baffle system and a simple beam dump. Successful stray light reduction has enabled detection of scattered signal, and Rayleigh scattering has been used to provide a relative calibration. Initial temperature measurements have been made and data analysis algorithms are under development.

  5. Comparative electron temperature measurements of Thomson scattering and electron cyclotron emission diagnostics in TCABR plasmas

    SciTech Connect

    Alonso, M. P.; Figueiredo, A. C. A.; Berni, L. A.; Machida, M.

    2010-10-15

    We present the first simultaneous measurements of the Thomson scattering and electron cyclotron emission radiometer diagnostics performed at TCABR tokamak with Alfven wave heating. The Thomson scattering diagnostic is an upgraded version of the one previously installed at the ISTTOK tokamak, while the electron cyclotron emission radiometer employs a heterodyne sweeping radiometer. For purely Ohmic discharges, the electron temperature measurements from both diagnostics are in good agreement. Additional Alfven wave heating does not affect the capability of the Thomson scattering diagnostic to measure the instantaneous electron temperature, whereas measurements from the electron cyclotron emission radiometer become underestimates of the actual temperature values.

  6. Laser Thomson Scattering Diagnostics in the Low-Temperature Plasmas

    NASA Astrophysics Data System (ADS)

    Woo, Hyun-Jong; Chung, Kyu-Sun

    2008-10-01

    Laser Thomson Scattering (LTS) is the non-invasive method for measuring the electron temperature and its density, which can be used for the calibrations of electric probes within collisional and magnetized plasmas. For LTS diagnostics in the low-temperature plasmas, one need to special optics for detection of the scattered light with restricting the Rayleigh and Stray lights. For this, one uses the Triple Grating Spectrometer (TGS), which is composed of Rayleigh block (notch filter for Rayleigh light) and double grating filter (DGF). All focusing lenses are used with achromatic doublet configuration for reducing the non-linear optical effects such as spherical aberration, coma, etc. The specifications of the grating and achromatic doublet lens are 1800 gr/mm with the dimensions of 84 mm x 84 mm and 400 mm of focal length with the diameter of 100 mm, respectively. In this configurations, the linear dispersion is given as 1.006 nm/mm. Considering the dimension of Charged Coupled Device (CCD) with the linear dispersion, the LTS system can be measure the electron temperatures of less than 10 eV (in most laboratory plasmas). The initial measurement of LTS measurement and comparative study with single probe are done in Divertor Plasma Simulator (DiPS) with the following plasma parameters; plasma density of 10^11-10^13 cm-3, electron temperature of 1-4 eV, and the magnetic field of 0.2-1 kG, respectively.

  7. Central Thomson scattering upgrade on DIII-D

    SciTech Connect

    Nilson, D.G.; Stallard, B.W.; Carlstrom, T.N.; Hsieh, C.L.; Stockdale, R.E.

    1997-11-01

    The existing 36 channel Thomson scattering system on the DIII-D tokamak measures the plasma temperature and density in the core region. However, with the recent interest in core peaked density profiles, coverage needs to be extended into the magnetic axis. This paper addresses the technical issues involved with extending the viewing region from a major radius of 194 cm to 165 cm. At least one of the existing seven core laser beams will be rerouted to probe the plasma horizontally instead of vertically. To do this, a rigid extension of the existing laser/collection optics tower will be built to route the laser to a nearby tangential port. A fiber bundle array from one of the two existing core plasma collection optics sets will be rotated to allow up to 10 of the 36 core channels to view along this new beam path. A new in-vessel absorbing glass laser dump must be developed since there are no appropriate laser beam exit ports. The close proximity of this laser dump to the viewing region presents stray light issues that must be resolved to allow for an accurate density calibration using Rayleigh scattering in argon gas.

  8. Multipass/multipulse Thomson scattering on CDX-U (abstract)

    SciTech Connect

    Stutman, D.; Hwang, Y.S.; Menard, J.; Choe, W.; Ono, M.; Petrov, Y.; Gusev, V.; Mukhin, E.

    1997-01-01

    A multipass/multipulse Thomson scattering system has been implemented on CDX-U in collaboration with the Ioffe Institute, St. Petersburg. The system consists of a low energy (1.5{endash} 2.5 J), passively Q-switched ruby laser, and a multipass optical cavity enclosing the plasma. Multiple reflections of the beam within the cavity increase by about an order of magnitude the number of scattered photons, allowing temperature density to be measured with good accuracy even at very low plasma density. By feeding the returned beam back into the laser, the system can deliver several pulses over a 1 ms period. However, the experiments on CDX-U show that a mechanical shock wave reaching the multipass system affects the feedback and laser output per pulse drops significantly. Therefore we operate the system by fine tuning the laser cavity, so that output is practically independent of feedback from multipass cavity. Also, by optimizing the transmission of the passive Q-switch and the pumping power, we obtain that laser output is concentrated in single large pulse of 2{endash}2.5 J energy. We achieve circulating energy in the plasma in excess of 12 J per pulse, while minimizing at the same time stray light. As shown by results from CDX-U, this enables in some cases better than 10{percent} accuracy, despite relatively low plasma density conditions. {copyright} {ital 1997 American Institute of Physics.}

  9. Multipass/multipulse Thomson scattering on CDX-U (abstract)

    NASA Astrophysics Data System (ADS)

    Stutman, D.; Hwang, Y. S.; Menard, J.; Choe, W.; Ono, M.; Petrov, Y.; Gusev, V.; Mukhin, E.

    1997-01-01

    A multipass/multipulse Thomson scattering system has been implemented on CDX-U in collaboration with the Ioffe Institute, St. Petersburg. The system consists of a low energy (1.5- 2.5 J), passively Q-switched ruby laser, and a multipass optical cavity enclosing the plasma. Multiple reflections of the beam within the cavity increase by about an order of magnitude the number of scattered photons, allowing temperature density to be measured with good accuracy even at very low plasma density. By feeding the returned beam back into the laser, the system can deliver several pulses over a 1 ms period. However, the experiments on CDX-U show that a mechanical shock wave reaching the multipass system affects the feedback and laser output per pulse drops significantly. Therefore we operate the system by fine tuning the laser cavity, so that output is practically independent of feedback from multipass cavity. Also, by optimizing the transmission of the passive Q-switch and the pumping power, we obtain that laser output is concentrated in single large pulse of 2-2.5 J energy. We achieve circulating energy in the plasma in excess of 12 J per pulse, while minimizing at the same time stray light. As shown by results from CDX-U, this enables in some cases better than 10% accuracy, despite relatively low plasma density conditions.

  10. Beam-shape effects in nonlinear Compton and Thomson scattering

    SciTech Connect

    Heinzl, T.; Seipt, D.; Kaempfer, B.

    2010-02-15

    We discuss intensity effects in collisions between beams of optical photons from a high-power laser and relativistic electrons. Our main focus is on the modifications of the emission spectra due to realistic finite-beam geometries. By carefully analyzing the classical limit we precisely quantify the distinction between strong-field QED Compton scattering and classical Thomson scattering. A purely classical, but fully covariant, calculation of the bremsstrahlung emitted by an electron in a plane-wave laser field yields radiation into harmonics, as expected. This result is generalized to pulses of finite duration and explains the appearance of line broadening and harmonic substructure as an interference phenomenon. The ensuing numerical treatment confirms that strong focusing of the laser leads to a broad continuum while higher harmonics become visible only at moderate focusing, and hence lower intensity. We present a scaling law for the backscattered photon spectral density which facilitates averaging over electron beam phase space. Finally, we propose a set of realistic parameters such that the observation of intensity-induced spectral red shift, higher harmonics, and their substructure becomes feasible.

  11. Dual-laser calibration of Thomson scattering systems in ITER and RFX-mod

    NASA Astrophysics Data System (ADS)

    Giudicotti, L.; Pasqualotto, R.

    2014-04-01

    We first review the principles of the dual-laser calibration technique for measuring the relative sensitivities of the spectral channels in a Thomson scattering (TS) diagnostic system by detecting with the same spectrometer the spectra scattered by the same plasma volume from two laser pulses of different wavelengths. A new data analysis method is then introduced, based on the minimization of a single χ2 function, that provides a simpler and more convenient way to determine the measurement errors on the calibration coefficients. The new analysis method is used here to investigate the expected performances of this calibration technique in the core LIDAR TS system of ITER currently under design and in the conventional multipoint TS system of RFX-mod. By calculating the expected calibration errors for typical plasma scenarios we discuss the different possible choices of the calibration laser, the characteristics of the calibrating plasma and other system parameters with an impact on the application of the technique. For ITER core LIDAR TS, designed with Nd : YAG at 1064 nm as main laser, a ruby laser shows slightly better performances as a calibration laser compared with a second harmonic Nd : YAG and a calibration accuracy ˜1% can be achieved in a relatively small number of pairs of laser pulses. In RFX-mod the combination of a Nd : YAG and a Nd : YLF laser systems is the only viable choice, and we find that, in spite of the small difference between the two wavelengths (λ = 1064 nm and λ = 1053 nm, respectively), dual-laser calibration is still possible to the required accuracy with an affordable number of pairs of laser shots.

  12. Installation of a Thomson scattering diagnostic on the Compact Toroidal Hybrid Experiment

    NASA Astrophysics Data System (ADS)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Cianciosa, M. R.

    2015-11-01

    A Thomson scattering system is being commissioned for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH), a five-field period current-carrying torsatron. The initial system takes a single point measurement on the magnetic axis and will be used to assess options for an expansion to a multi-point system to enable better 3D equilibrium reconstructions using the V3FIT code. A single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both current-carrying plasmas and future gyrotron-heated stellarator plasmas. The beam, generated by a frequency doubled Continuum 2 J, Nd:YaG laser, is passed vertically through an entrance Brewster window and a two-aperture optical baffle system to minimize stray light. The beam line is designed to propagate ~ 8 m to the mid-plane of the CTH device with the beam diameter < 3 mm inside the plasma volume. An Andor iStar DH740-18U-C3 image intensified CCD camera is used in conjunction with a Holospec f/1.8 spectrograph to collect the red-shifted scattered light from 532-580 nm. A single point system will initially measure plasmas with core electron temperatures of 100 to 200 eV and densities of 5 ×1018 to 5 ×1019 m-3. This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  13. Kinetic Enhancement of Raman Backscatter, and Electron Acoustic Thomson Scatter

    SciTech Connect

    Strozzi, D J; Williams, E A; Langdon, A B; Bers, A

    2006-09-01

    1-D Eulerian Vlasov-Maxwell simulations are presented which show kinetic enhancement of stimulated Raman backscatter (SRBS) due to electron trapping in regimes of heavy linear Landau damping. The conventional Raman Langmuir wave is transformed into a set of beam acoustic modes [L. Yin et al., Phys. Rev. E 73, 025401 (2006)]. For the first time, a low phase velocity electron acoustic wave (EAW) is seen developing from the self-consistent Raman physics. Backscatter of the pump laser off the EAW fluctuations is reported and referred to as electron acoustic Thomson scatter. This light is similar in wavelength to, although much lower in amplitude than, the reflected light between the pump and SRBS wavelengths observed in single hot spot experiments, and previously interpreted as stimulated electron acoustic scatter [D. S. Montgomery et al., Phys. Rev. Lett. 87, 155001 (2001)]. The EAW observed in our simulations is strongest well below the phase-matched frequency for electron acoustic scatter, and therefore the EAW is not produced by it. The beating of different beam acoustic modes is proposed as the EAW excitation mechanism, and is called beam acoustic decay. Supporting evidence for this process, including bispectral analysis, is presented. The linear electrostatic modes, found by projecting the numerical distribution function onto a Gauss-Hermite basis, include beam acoustic modes (some of which are unstable even without parametric coupling to light waves) and a strongly-damped EAW similar to the observed one. This linear EAW results from non-Maxwellian features in the electron distribution, rather than nonlinearity due to electron trapping.

  14. Spectroscopic Analysis and Thomson Scattering Diagnostics of Wire Produced Plasma

    NASA Astrophysics Data System (ADS)

    Plechaty, Christopher; Sotnikov, Vladimir; Main, Daniel; Caplinger, James; Wallerstein, Austin; Kim, Tony

    2014-10-01

    The Lower Hybrid Drift Instability (LHDI) in plasma is driven by the presence of inhomogeneities in density, temperature, or magnetic field (Krall 1971, Davidson 1977), and occurs in systems where the electrons are magnetized and the ions are effectively unmagnetized. The LHDI is thought to occur in magnetic reconnection (Huba 1977), and has also been investigated as a mitigation technique which can allow for communications to take place through the plasma formed around hypersonic aircraft (Sotnikov 2010). To further understand the phenomenology of the LHDI, we plan to carry out experiments at the Air Force Research Laboratory, in the newly formed Plasma Physics Sensors Laboratory. In experiment, a pulsed power generator is employed to produce plasma by passing current through single, or dual-wire configurations. To characterize the plasma, a Thomson scattering diagnostic is employed, along with a visible spectroscopy diagnostic. This work was performed under the auspices of the U.S. Department of Defense by Riverside Research under Contract BAA-FA8650-13-C-1539.

  15. Laser Thomson Scattering Diagnostics of Pulsed Filamentary Discharge Plasmas

    NASA Astrophysics Data System (ADS)

    Bolouki, Nima

    2012-10-01

    Laser Thomson scattering (LTS) has been applied to measure spatiotemporal evolution of electron density and electron temperature in a pulsed filamentary discharge. The light source of LTS is the second harmonics Nd:YAG laser with a energy of 8 mJ. Also a triple grating spectrometer (TGS) having high rejection rate for stray light is used to measure LTS spectra. In our experimental conditions, non-thermal and non-equilibrium micro-plasmas are generated at round atmospheric pressure. Moreover, the electrode set in this experiment is consisted of a needle electrode and a hemispherical electrode with an inter-electrode gap of 0.5 mm. The total electric charge that flows through the discharge channel vary from 20 nC to 850 nC by changing capacitance in electrical circuit. We could show that the total charge variation leads to increase in electron density from 10^22 m-3 to 10^23 m-3. However, the electron temperature remains almost constant at the main discharge. In order to investigate the streamer phase, we changed the gap up to 16mm, and then performed the LTS method to measure the electron density and electron temperature.

  16. Diagnostics of Dielectric Barrier Microdischarges Using Laser Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Bolouki, Nima; Tomita, Kentaro; Yamagata, Yukihiko; Uchino, Kiichiro

    2011-10-01

    We have been developing a laser Thomson scattering technique to apply for dielectric barrier pulsed discharges. The light source of LTS is the second harmonics of a Nd:YAG laser with a energy of 8 mJ. Also a triple grating spectrometer which is equipped with a spatial filter for eliminating Rayleigh and stray lights is used to measure LTS spectra. The dielectric barrier discharge is generated in neon gas at around atmospheric pressure of 400 Torr by applying the bipolar pulses at a frequency of 50 Hz with a peak value of 3 kV. The electrode set in this experiment is consisted of a needle electrode and a hemispherical electrode with an inter-electrode gap of 0.5 mm. Teflon as a dielectric layer is coated on the hemispherical electrode with a thickness of 200 μm. In this experiment, the peak current of discharge was about 3 A and the total electric charge that flows through the discharge channel was estimated to be 20-30 nC. Finally, we applied LTS successfully as a diagnostics method in DBD. Temporal evolution of electron density and temperature could also be measured. It has been investigated that the peak values of electron density and electron temperature at the center of the pulsed filament discharge to be (1.0 +0.1) ×1022 m-3 and 2.62 (+0.2) eV.

  17. Focusing effects in laser-electron Thomson scattering

    NASA Astrophysics Data System (ADS)

    Harvey, Chris; Marklund, Mattias; Holkundkar, Amol R.

    2016-09-01

    We study the effects of laser pulse focusing on the spectral properties of Thomson scattered radiation. Modeling the laser as a paraxial beam we find that, in all but the most extreme cases of focusing, the temporal envelope has a much bigger effect on the spectrum than the focusing itself. For the case of ultrashort pulses, where the paraxial model is no longer valid, we adopt a subcycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focusing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to subwavelength spot sizes produce spectra that are qualitatively similar to those from subcycle pulses due to the shortening of the pulse with focusing. Finally, we study high-intensity fields and find that, in general, the focusing makes negligible difference to the spectra in the regime of radiation reaction.

  18. Observation of Hot Remnant Islands using Fast Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Morton, L. A.; Young, W. C.; den Hartog, D. J.; Hegna, C. C.; Parke, E.; Reusch, J. A.; Jacobson, C. M.

    2015-11-01

    The MST Fast Thomson Scattering Laser, operating with repetition rates of up to 100 kHz for up to 25 laser pulses, has allowed direct observation of temperature structures produced by tearing modes rotating at 10 - 20 kHz. A hot spot observed by Fast TS coincides with the O-point of the dominant m/n = 1/6 mode reconstructed by MHD modeling from edge magnetic measurements. The electron thermal conductivity inside the island is estimated from power balance to be 75 m2/s. However, MHD modeling also predicts overlap between the n =6 and n =7 islands, producing chaotic field lines and total loss of the island flux surfaces. Ensemble-averaged data from the slower burst laser (25 kHz for 8 pulses) also indicates overlap between the temperature fluctuations associated with these modes. These temperature fluctuation also exhibits the large higher-harmonic content that characterizes the hot island in the single-shot cases. DEBS finite-beta MHD simulations qualitatively reproduce MST temperature structures in certain cases. This work is supported by the US DoE and the NSF.

  19. Chevron beam dump for ITER edge Thomson scattering system

    NASA Astrophysics Data System (ADS)

    Yatsuka, E.; Hatae, T.; Vayakis, G.; Bassan, M.; Itami, K.

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  20. Chevron beam dump for ITER edge Thomson scattering system.

    PubMed

    Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

    2013-10-01

    This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

  1. X-Ray Thomson Scattering Without the Chihara Decomposition

    NASA Astrophysics Data System (ADS)

    Magyar, Rudolph; Baczewski, Andrew; Shulenburger, Luke; Hansen, Stephanie B.; Desjarlais, Michael P.; Sandia National Laboratories Collaboration

    X-Ray Thomson Scattering is an important experimental technique used in dynamic compression experiments to measure the properties of warm dense matter. The fundamental property probed in these experiments is the electronic dynamic structure factor that is typically modeled using an empirical three-term decomposition (Chihara, J. Phys. F, 1987). One of the crucial assumptions of this decomposition is that the system's electrons can be either classified as bound to ions or free. This decomposition may not be accurate for materials in the warm dense regime. We present unambiguous first principles calculations of the dynamic structure factor independent of the Chihara decomposition that can be used to benchmark these assumptions. Results are generated using a finite-temperature real-time time-dependent density functional theory applied for the first time in these conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.

  2. Initial Thomson Scattering Survey of Local Helicity Injection and Ohmic Plasmas at the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

    Schlossberg, D. J.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Winz, G. R.

    2014-10-01

    A multipoint Thomson scattering diagnostic has recently been installed on the Pegasus ST. The system utilizes a frequency-doubled Nd:YAG laser (λ0 ~ 532 nm), spectrometers with volume phase holographic gratings, and a gated, intensified CCD camera. It provides measurements of Te and ne at 8 spatial locations for each spectrometer once per discharge. A new multiple aperture and beam dump system has been implemented to mitigate interference from stray light. This system has provided initial measurements in the core region of plasmas initiated by local helicity injection (LHI), as well as conventional Ohmic L- and H-mode discharges. Multi-shot averages of low-density (ne ~ 3 ×1018 m-3) , Ip ~ 0 . 1 MA LHI discharges show central Te ~ 75 eV at the end of the helicity injection phase. Ip ~ 0 . 13 MA Ohmic plasmas at moderate densities (ne ~ 2 ×1019 m-3) have core Te ~ 150 eV in L-mode. Generally, these plasmas do not reach transport equilibrium in the short 25 ms pulse length available. After an L-H transition, strong spectral broadening indicates increasing Te, to values above the range of the present spectrometer system with a high-dispersion VPH grating. Near-term system upgrades will focus on deploying a second spectrometer, with a lower-dispersion grating capable of measuring the 0.1-1.0 keV range. The second spectrometer system will also increase the available number of spatial channels, enabling study of H-mode pedestal structure. Work supported by US DOE Grant DE-FG02-96ER54375.

  3. Single-pulse Multi-point Multi-component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.; Gaffney, Richard L., Jr.; Cutler, Andrew W.

    2006-01-01

    A simultaneous multi-point, multi-component velocimeter using interferometric detection of the Doppler shift of Rayleigh, Mie, and Rayleigh-Brillouin scattered light in supersonic flow is described. The system uses up to three sets of collection optics and one beam combiner for the reference laser light to form a single collimated beam. The planar Fabry-Perot interferometer used in the imaging mode for frequency detection preserves the spatial distribution of the signal reasonably well. Single-pulse multi-points measurements of up to two orthogonal and one non-orthogonal components of velocity in a Mach 2 free jet were performed to demonstrate the technique. The average velocity measurements show a close agreement with the CFD calculations using the VULCAN code.

  4. A simple, high performance Thomson scattering diagnostic for high temperature plasma research

    SciTech Connect

    Hartog, D.J.D.; Cekic, M.

    1994-02-01

    This Thomson scattering diagnostic is used to measure the electron temperature and density of the plasma in the MST reversed-field pinch, a magnetic confinement fusion research device. This diagnostic system is unique for its type in that it combines high performance with simple design and low cost components. In the design of this instrument, careful attention was given to the suppression of stray laser line light with simple and effective beam dumps, viewing dumps, aperatures, and a holographic edge filter. This allows the use of a single grating monochromator for dispersion of the Thomson scattered spectrum onto the microchannel plate detector. Alignment and calibration procedures for the laser beam delivery system, the scattered light collection system, and the spectrometer and detector are described. A sample Thomson scattered spectrum illustrates typical data.

  5. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid

    NASA Astrophysics Data System (ADS)

    Traverso, Peter; Maurer, David; Hartwell, Gregory; Knowlton, Stephen; Miller, Matthew

    2012-10-01

    The Compact Toroidal Hybrid (CTH) experiment is investigating the avoidance of disruptions in ohmically driven torsaton plasmas in which the ratio of vacuum or external coil transform to the total transform generated by the plasma current and external coils can be lower than 10%. To aid in the characterization and equilibrium reconstruction of these current-carrying CTH plasmas a new Thomson scattering system is under development. Details of the Thomson scattering system design and implementation will be discussed including choice of laser scattering geometry, laser wavelength, stray laser light rejection strategy, collections optics, and spectrometer design.

  6. Raman calibration of the HT-7 yttrium aluminum garnet Thomson scattering for electron density measurements

    SciTech Connect

    Zang Qing; Zhao Junyu; Gao Xiang; Shi Lingwei; Zhang Tao; Xi Xiaoqi; Yang Li; Hu Qingsheng; Sajjad, S.

    2007-11-15

    A multipulse neodym doped yttrium aluminum garnet laser Thomson scattering system calibrated by the anti-Stokes rotational Raman scattering from nitrogen gas had been developed in the HT-7 superconducting Tokmak. By virtue of this system, measured electron density results of the plasma were obtained. The results showed good repeatability and its total uncertainty was estimated to be {+-}18%.

  7. Short-interval multi-laser Thomson scattering measurements of hydrogen pellet ablation in LHD

    SciTech Connect

    Yasuhara, R. Sakamoto, R.; Yamada, I.; Motojima, G.; Hayashi, H.

    2014-11-15

    Thomson scattering forms an important aspect of measuring the electron density and temperature profiles of plasmas. In this study, we demonstrate Thomson scattering measurements obtained over a short interval (<1 ms) by using an event triggering system with a multi-laser configuration. We attempt to use our system to obtain the electron temperature and density profiles before and immediately after pellet injection into the large helical device. The obtained profiles exhibit dramatic changes after pellet injection as per our shot-by-shot measurements. We believe that this measurement technique will contribute towards a better understanding of the physics of the pellet deposition.

  8. Experimental evidence of the effect of heat flux on thomson scattering off ion acoustic waves

    PubMed

    Amiranoff; Baton; Huller; Malka; Modena; Mounaix; Galloudec; Rousseaux; Salvati

    2000-02-01

    Thomson self-scattering measurements are performed in a preionized helium gas jet plasma at different locations along the laser propagation direction. A systematic and important variation of the intensity ratio between the blue and the red ion spectral components is observed, depending on whether the location of the probed region is in front of or behind the focal plane. A simple theoretical calculation of Thomson scattering shows that this behavior can be qualitatively understood in terms of a deformation of the electron distribution function due to the return current correlated with the classical thermal heat flux. PMID:11046481

  9. Simulated performance of the optical Thomson scattering diagnostic designed for the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Ross, J. S.; Datte, P.; Divol, L.; Galbraith, J.; Froula, D. H.; Glenzer, S. H.; Hatch, B.; Katz, J.; Kilkenny, J.; Landen, O.; Manuel, A. M.; Molander, W.; Montgomery, D. S.; Moody, J. D.; Swadling, G.; Weaver, J.

    2016-11-01

    An optical Thomson scattering diagnostic has been designed for the National Ignition Facility to characterize under-dense plasmas. We report on the design of the system and the expected performance for different target configurations. The diagnostic is designed to spatially and temporally resolve the Thomson scattered light from laser driven targets. The diagnostic will collect scattered light from a 50 × 50 × 200 μm volume. The optical design allows operation with different probe laser wavelengths. A deep-UV probe beam (λ0 = 210 nm) will be used to Thomson scatter from electron plasma densities of ˜5 × 1020 cm-3 while a 3ω probe will be used for plasma densities of ˜1 × 1019 cm-3. The diagnostic package contains two spectrometers: the first to resolve Thomson scattering from ion acoustic wave fluctuations and the second to resolve scattering from electron plasma wave fluctuations. Expected signal levels relative to background will be presented for typical target configurations (hohlraums and a planar foil).

  10. Improvement in data processing of Thomson scattering diagnostic on HL-2A tokamak

    NASA Astrophysics Data System (ADS)

    Liu, C. H.; Wang, Y. Q.; Feng, Z.; Huang, Y.

    2015-12-01

    There are two types of digitizers to acquire the values of Thomson scattering signals in HL-2A tokamak. One is charge-sensitive analogue-to-digital converters (Q-ADCs) which simply integrates the signal over a gate interval, and the other is transient recorders with 12 bits resolution and 1 GHz sampling rate at each channel. Because the Thomson scattering diagnostic is prone to electrical noisy environment, in which Q-switched Nd:YAG lasers and polychromators are located closely to the HL-2A device, the high speed transient digitizers are found helpful to reduce noise overlapped in Thomson scattering signals. After triggered by the front of TTL pulse generated by laser light, data acquisition is fulfilled from -250 ns to 250 ns, so that the temporal evolution of Thomson scattering signals is obtained. A Gaussian function is utilized to fit the pulse shape of the digitized scattering signal by nonlinear least square methods. By pulse fitting and data processing, the influence of background perturbations is substantially reduced.

  11. First results from the Thomson scattering diagnostic on Proto-MPEX

    SciTech Connect

    Biewer, Theodore M; Meitner, Steven J; Rapp, Juergen

    2016-01-01

    A Thomson scattering diagnostic has been successfully implemented on the prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory. The diagnostic collects the light scattered by plasma electrons and spectroscopically resolves the Doppler shift imparted to the light by the velocity of the electrons. The spread in velocities is proportional to the electron temperature, while the total number of photons is proportional to the electron density. Thomson scattering is a technique used on many devices to measure the electron temperature (Te) and electron density (ne) of the plasma. A challenging aspect of the technique is to discriminate the small number of Thomson scattered photons against the large peak of background photons from the high-power laser used to probe the plasma. A variety of methods are used to mitigate the background photons in Proto-MPEX, including Brewster angled windows, viewing dumps, and light baffles. With these methods, first results were measured from Argon plasmas in Proto-MPEX, indicating Te ~ 2 eV and ne ~ 1x1019 m-3. The configuration of the Proto-MPEX Thomson scattering diagnostic will be described and plans for improvement will be given.

  12. Double-confocal resonator for X-ray generation via intracavity Thomson scattering

    SciTech Connect

    Xie, M.

    1995-12-31

    There has been a growing interest in developing compact X-ray sources through Thomson scattering of a laser beam by a relativistic electron beam. For higher X-ray flux it is desirable to have the scattering to occur inside an optical resonator where the laser power is higher. In this paper I propose a double-confocal resonator design optimized for head-on Thomson scattering inside an FEL oscillator and analyze its performance taking into account the diffraction and FEL gain. A double confocal resonator is equivalent to two confocal resonators in series. Such a resonator has several advantages: it couples electron beam through and X-ray out of the cavity with holes on cavity mirrors, thus allowing the system to be compact; it supports the FEL mode with minimal diffraction loss through the holes; it provides a laser focus in the forward direction for a better mode overlap with the electron beam; and it provides a focus at the same location in the backward direction for higher Thomson scattering efficiency; in addition, the mode size at the focal point and hence the Rayleigh range can be adjusted simply through intracavity apertures; furthermore, it gives a large mode size at the mirrors to reduce power loading. Simulations as well as analytical results will be presented. Also other configurations of intracavity Thomson scattering where the double-confocal resonator could be useful will be discussed.

  13. Conceptual design of new polychromator on Thomson scattering system to measure Z{sub eff}

    SciTech Connect

    Lee, Jongha; Oh, Seungtae; Wi, Hanmin; Oh, Youngkook; Yamada, I.; Narihara, K.; Kawahata, K.; Jeon, Jongsu

    2012-10-15

    To measure the Z{sub eff} with electron temperature (T{sub e}) and electron density (n{sub e}) profiles at the same time and the same position in the KSTAR tokamak, we design a new polychromator for Thomson scattering system that has additional function. The additional function is measuring bremsstrahlung intensity to calculate Z{sub eff} independent of Thomson signals. For this new polychromator, we design and fabricate a collimation lens set, and interference filter that has center wavelength of 523 nm and 2 nm FWHM. Finally, we change the lenses, detector diodes, and add the bremsstrahlung filter on the KSTAR edge Thomson scattering polychromator. Then this new polychromator was tested by Tungsten light and monochromator.

  14. Efficient Thomson Scattering Measurement System for the Diagnostics of Processing Plasmas

    NASA Astrophysics Data System (ADS)

    Kono, Akihiro; Nakatani, Keigo

    1999-10-01

    Optical measurement of electron energy distribution function (EEDF) is desirable for the diagnostics of processing plasmas. In Thomson scattering measurements, EEDF is directly derived from the Doppler broadened profile of the laser light scattered by free electrons, but one must solve the problem of very low signal intensity due to the small scattering cross section. We have constructed an efficient Thomson scattering measurement system for the diagnostics of processing plasmas, which is capable of performing multi-channel measurement of the Doppler broadened profile without suffering from strong interference due to Rayleigh scattering and other stray scattering. The measurement system consists of a specially designed triple monochromator and an ICCD camera. The plasma is irradiated by a frequency-doubled Nd:YAG laser (532 nm). With the aid of a spatial filter between the first and second stage, the triple monochromator outputs the dispersed scattered light with the center wavelength region (532 ± 0.5 nm) eliminated, enabling multi-channel measurements with the ICCD camera in the photon-counting mode. Use of a lens system as the focusing elements in the monochromator enables high transmittance and low aberration, both serving for a high signal collection efficiency. Preliminary Thomson scattering measurements indicated a promising performance of the measurement system.

  15. Direct observation of the two-plasmon-decay common plasma wave using ultraviolet Thomson scattering.

    PubMed

    Follett, R K; Edgell, D H; Henchen, R J; Hu, S X; Katz, J; Michel, D T; Myatt, J F; Shaw, J; Froula, D H

    2015-03-01

    A 263-nm Thomson-scattering beam was used to directly probe two-plasmon-decay (TPD) excited electron plasma waves (EPWs) driven by between two and five 351-nm beams on the OMEGA Laser System. The amplitude of these waves was nearly independent of the number of drive beams at constant overlapped intensity, showing that the observed EPWs are common to the multiple beams. In an experimental configuration where the Thomson-scattering diagnostic was not wave matched to the common TPD EPWs, a broad spectrum of TPD-driven EPWs was observed, indicative of nonlinear effects associated with TPD saturation. Electron plasma waves corresponding to Langmuir decay of TPD EPWs were observed in both Thomson-scattering spectra, suggesting the Langmuir decay instability as a TPD saturation mechanism. Simulated Thomson-scattering spectra from three-dimensional numerical solutions of the extended Zakharov equations of TPD are in excellent agreement with the experimental spectra and verify the presence of the Langmuir decay instability.

  16. Direct observation of the two-plasmon-decay common plasma wave using ultraviolet Thomson scattering

    SciTech Connect

    Follett, R. K.; Edgell, D. H.; Henchen, R. J.; Hu, S. X.; Katz, J.; Michel, D. T.; Myatt, J. F.; Shaw, J.; Froula, D. H.

    2015-03-26

    A 263-nm Thomson-scattering beam was used to directly probe two-plasmon-decay (TPD) excited electron plasma waves (EPWs) driven by between two and five 351-nm beams on the OMEGA Laser System. The amplitude of these waves was nearly independent of the number of drive beams at constant overlapped intensity, showing that the observed EPWs are common to the multiple beams. In an experimental configuration where the Thomson-scattering diagnostic was not wave matched to the common TPD EPWs, a broad spectrum of TPD-driven EPWs was observed, indicative of nonlinear effects associated with TPD saturation. Electron plasma waves corresponding to Langmuir decay of TPD EPWs were observed in both Thomson-scattering spectra, suggesting the Langmuir decay instability as a TPD saturation mechanism. Simulated Thomson-scattering spectra from three-dimensional numerical solutions of the extended Zakharov equations of TPD are in excellent agreement with the experimental spectra and verify the presence of the Langmuir decay instability.

  17. Direct observation of the two-plasmon-decay common plasma wave using ultraviolet Thomson scattering.

    PubMed

    Follett, R K; Edgell, D H; Henchen, R J; Hu, S X; Katz, J; Michel, D T; Myatt, J F; Shaw, J; Froula, D H

    2015-03-01

    A 263-nm Thomson-scattering beam was used to directly probe two-plasmon-decay (TPD) excited electron plasma waves (EPWs) driven by between two and five 351-nm beams on the OMEGA Laser System. The amplitude of these waves was nearly independent of the number of drive beams at constant overlapped intensity, showing that the observed EPWs are common to the multiple beams. In an experimental configuration where the Thomson-scattering diagnostic was not wave matched to the common TPD EPWs, a broad spectrum of TPD-driven EPWs was observed, indicative of nonlinear effects associated with TPD saturation. Electron plasma waves corresponding to Langmuir decay of TPD EPWs were observed in both Thomson-scattering spectra, suggesting the Langmuir decay instability as a TPD saturation mechanism. Simulated Thomson-scattering spectra from three-dimensional numerical solutions of the extended Zakharov equations of TPD are in excellent agreement with the experimental spectra and verify the presence of the Langmuir decay instability. PMID:25871046

  18. Reply to "Comment on `Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping'"

    NASA Astrophysics Data System (ADS)

    Rykovanov, S. G.; Geddes, C. G. R.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2016-09-01

    We reply to Terzic and Krafft's forgoing Comment [Phys. Rev. Accel. Beams, Comment on "Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping" 19 (2016)]. We disagree with the conclusion of the Comment regarding the novelty of solutions and the citations presented in our paper.

  19. Soft X-Ray Thomson Scattering in Warm Dense Hydrogen at FLASH

    SciTech Connect

    Faustlin, R R; Toleikis, S; Bornath, T; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Mithen, J; Przystawik, A; Redlin, H; Redmer, R; Reinholz, H; Ropke, G; Tavella, F; Thiele, R; Tiggesbaumker, J; Uschmann, I; Zastrau, U; Tschentscher, T

    2009-07-15

    We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with {approx}200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 {micro}m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

  20. Spectral characterization of Compact Toroidal Hybrid plasmas in preparation for Thomson scattering measurements

    NASA Astrophysics Data System (ADS)

    Goforth, M. M.; Loch, S. D.; Maurer, D. A.; Pearce, A. J.; Traverso, P. J.

    2014-10-01

    A Thomson scattering system is in development for the Compact Toroidal Hybrid (CTH) experiment to provide localized, internal electron temperature and density measurements. Thomson scattering yields accurate information on the internal plasma electron pressure profile, which will aid in the equilibrium reconstruction of CTH plasmas using the V3FIT code. The expected Thomson scattered signal is approximately 1015 times less than the incident laser light, and can be overwhelmed by stray laser light, background plasma emission, and intrinsic detector noise. Background plasma emission measurements in the visible spectral region near the planned laser wavelength of 532 nm are underway using a Holospec f/1.8 spectrometer and an And or iStar image intensified CCD camera to quantify line and continuum background levels. In addition, impurity line identification and plans for a separate line-of-sight averaged impurity temperature and density measurement capability employing the Thomson spectrometer are in progress. This work is supported by US DOE Grant DE-FG-02-00ER54610 and by the Auburn University Undergraduate Research Fellowship.

  1. A high-power spatial filter for Thomson scattering stray light reduction

    NASA Astrophysics Data System (ADS)

    Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

    2011-03-01

    The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

  2. Imaging x-ray Thomson scattering spectrometer design and demonstration (invited).

    PubMed

    Gamboa, E J; Huntington, C M; Trantham, M R; Keiter, P A; Drake, R P; Montgomery, D S; Benage, J F; Letzring, S A

    2012-10-01

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  3. Imaging x-ray Thomson scattering spectrometer design and demonstration (invited)a)

    NASA Astrophysics Data System (ADS)

    Gamboa, E. J.; Huntington, C. M.; Trantham, M. R.; Keiter, P. A.; Drake, R. P.; Montgomery, D. S.; Benage, J. F.; Letzring, S. A.

    2012-10-01

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  4. Coherent and incoherent Thomson scattering on an argon/hydrogen microwave plasma torch with transient behaviour

    NASA Astrophysics Data System (ADS)

    Obrusník, A.; Synek, P.; Hübner, S.; van der Mullen, J. J. A. M.; Zajíčková, L.; Nijdam, S.

    2016-10-01

    A new method of processing time-integrated coherent Thomson scattering spectra is presented, which provides not only the electron density and temperature but also information about the transient behaviour of the plasma. Therefore, it is an alternative to single-shot Thomson scattering measurements as long as the scattering is coherent. The method is applied to a microwave plasma torch operating in argon or a mixture of argon with hydrogen at atmospheric pressure. Electron densities up to 8\\cdot {{10}21} m-3 (ionization degree above 10-3) were observed, which is more than two times higher than presented in earlier works on comparable discharges. Additionally, a parametric study with respect to the argon/hydrogen ratio and the input power was carried out and the results are discussed together with earlier Stark broadening measurements on the same plasma.

  5. Nonlinear Thomson scattering of a relativistically strong tightly focused ultrashort laser pulse

    NASA Astrophysics Data System (ADS)

    Vais, O. E.; Bochkarev, S. G.; Bychenkov, V. Yu.

    2016-09-01

    The problem of nonlinear Thomson scattering of a relativistically strong linearly polarized ultrashort laser pulse tightly focused into a spot with a diameter of D F ≳ λ (where λ is the laser wavelength) is solved. The energy, spectral, and angular distributions of radiation generated due to Thomson scattering from test electrons located in the focal region are found. The characteristics of scattered radiation are studied as functions of the tightness of laser focusing and the initial position of test particles relative to the center of the focal region for a given laser pulse energy. It is demonstrated that the ultratight focusing is not optimal for obtaining the brightest and hardest source of secondary electromagnetic radiation. The hardest and shortest radiation pulse is generated when the beam waist diameter is ≃10λ.

  6. Electron beam final focus system for Thomson scattering at ELBE

    NASA Astrophysics Data System (ADS)

    Krämer, J. M.; Budde, M.; Bødker, F.; Irman, A.; Jochmann, A.; Kristensen, J. P.; Lehnert, U.; Michel, P.; Schramm, U.

    2016-09-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  7. A new dump system design for stray light reduction of Thomson scattering diagnostic system on EAST.

    PubMed

    Xiao, Shumei; Zang, Qing; Han, Xiaofeng; Wang, Tengfei; Yu, Jin; Zhao, Junyu

    2016-07-01

    Thomson scattering (TS) diagnostic is an important diagnostic for measuring electron temperature and density during plasma discharge. However, the measurement of Thomson scattering signal is disturbed by the stray light easily. The stray light sources in the Experimental Advanced Superconducting Tokamak (EAST) TS diagnostic system were analyzed by a simulation model of the diagnostic system, and simulation results show that the dump system is the primary stray light source. Based on the optics theory and the simulation analysis, a novel dump system including an improved beam trap was proposed and installed. The measurement results indicate that the new dump system can reduce more than 60% of the stray light for the diagnostic system, and the influence of stray light on the error of measured density decreases. PMID:27475558

  8. Design of a submillimeter laser Thomson scattering system for measurement of ion temperature in SUMMA

    NASA Technical Reports Server (NTRS)

    Praddaude, H. C.; Woskoboinikow, P.

    1978-01-01

    A thorough discussion of submillimeter laser Thomson scattering for the measurement of ion temperature in plasmas is presented. This technique is very promising and work is being actively pursued on the high power lasers and receivers necessary for its implementation. In this report we perform an overall system analysis of the Thomson scattering technique aimed to: (1) identify problem areas; (2) establish specifications for the main components of the apparatus; (3) study signal processing alternatives and identify the optimum signal handling procedure. Because of its importance for the successful implementation of this technique, we also review the work presently being carried out on the optically pumped submillimeter CH3F and D2O lasers.

  9. Development of a neural network technique for KSTAR Thomson scattering diagnostics

    NASA Astrophysics Data System (ADS)

    Lee, Seung Hun; Lee, J. H.; Yamada, I.; Park, Jae Sun

    2016-11-01

    Neural networks provide powerful approaches of dealing with nonlinear data and have been successfully applied to fusion plasma diagnostics and control systems. Controlling tokamak plasmas in real time is essential to measure the plasma parameters in situ. However, the χ2 method traditionally used in Thomson scattering diagnostics hampers real-time measurement due to the complexity of the calculations involved. In this study, we applied a neural network approach to Thomson scattering diagnostics in order to calculate the electron temperature, comparing the results to those obtained with the χ2 method. The best results were obtained for 103 training cycles and eight nodes in the hidden layer. Our neural network approach shows good agreement with the χ2 method and performs the calculation twenty times faster.

  10. A new dump system design for stray light reduction of Thomson scattering diagnostic system on EAST

    NASA Astrophysics Data System (ADS)

    Xiao, Shumei; Zang, Qing; Han, Xiaofeng; Wang, Tengfei; Yu, Jin; Zhao, Junyu

    2016-07-01

    Thomson scattering (TS) diagnostic is an important diagnostic for measuring electron temperature and density during plasma discharge. However, the measurement of Thomson scattering signal is disturbed by the stray light easily. The stray light sources in the Experimental Advanced Superconducting Tokamak (EAST) TS diagnostic system were analyzed by a simulation model of the diagnostic system, and simulation results show that the dump system is the primary stray light source. Based on the optics theory and the simulation analysis, a novel dump system including an improved beam trap was proposed and installed. The measurement results indicate that the new dump system can reduce more than 60% of the stray light for the diagnostic system, and the influence of stray light on the error of measured density decreases.

  11. Optimal Design of a Tunable Thomson-Scattering Based Gamma-Ray Source

    SciTech Connect

    Gibson, D J; Anderson, S G; Betts, S M; Hartemann, F V; Jovanovic, I; McNabb, D P; Messerly, M J; Pruet, J A; Shverdin, M Y; Siders, C W; Tremaine, A M; Barty, C J

    2007-06-07

    Thomson-Scattering based systems offer a path to high-brightness high-energy (> 1 MeV) x-ray and {gamma}-ray sources due to their favorable scaling with electron energy. LLNL is currently engaged in an effort to optimize such a device, dubbed the ''Thomson-Radiated Extreme X-Ray'' (T-REX) source, targeting up to 680 keV photon energy. Such a system requires precise design of the interaction between a high-intensity laser pulse and a high-brightness electron beam. Presented here are the optimal design parameters for such an interaction, including factors such as the collision angle, focal spot size, optimal bunch charge, and laser energy. These parameters were chosen based on extensive modeling using PARMELA and in-house, well-benchmarked scattering simulation codes.

  12. Measurements of Intrinsic Ion Bernstein Waves in a Tokamak by Collective Thomson Scattering

    SciTech Connect

    Korsholm, S. B.; Stejner, M.; Bindslev, H.; Furtula, V.; Leipold, F.; Meo, F.; Michelsen, P. K.; Moseev, D.; Nielsen, S. K.; Salewski, M.; Baar, M. de; Delabie, E.; Kantor, M.; Buerger, A.

    2011-04-22

    In this Letter we report measurements of collective Thomson scattering (CTS) spectra with clear signatures of ion Bernstein waves and ion cyclotron motion in tokamak plasmas. The measured spectra are in accordance with theoretical predictions and show clear sensitivity to variation in the density ratio of the main ion species in the plasma. Measurements with this novel diagnostic demonstrate that CTS can be used as a fuel ion ratio diagnostic in burning fusion plasma devices.

  13. Gyrotron collective Thomson scattering from plasma fluctuations in a Tara axicell

    SciTech Connect

    Machuzak, J.S.; Woskov, P.P.; Myer, R.C.; Mulligan, W.J.; Cohn, D.R.; Gerver, M.; Golovato, S.N.; Horne, S.; Kubota, S.; Post, R.S.; and others

    1988-08-01

    Collective Thomson scattering in the Tara Tandem Mirror axicell at MIT was accomplished with a 137-GHz, approx.0.4-kW, 75-ms pulsed gyrotron. Ion cyclotron waves, ion Bernstein wave harmonics, and other plasma fluctuations possibly due to microinstabilities and magnetohydrodynamic (MHD) activity have been observed during ion cyclotron resonance frequency (ICRF) heating. The observation of ion Bernstein waves may be due to an enhanced ion thermal fluctuation spectrum in an ICRF heated plasma.

  14. 21nm x-ray laser Thomson scattering of laser-heated exploding foil plasmas

    SciTech Connect

    Dunn, J; Rus, B; Mocek, T; Nelson, A J; Foord, M E; Rozmus, W; Baldis, H A; Shepherd, R L; Kozlova, M; Polan, J; Homer, P; Stupka, M

    2007-09-26

    Recent experiments were carried out on the Prague Asterix Laser System (PALS) towards the demonstration of a soft x-ray laser Thomson scattering diagnostic for a laser-produced exploding foil. The Thomson probe utilized the Ne-like zinc x-ray laser which was double-passed to deliver {approx}1 mJ of focused energy at 21.2 nm wavelength and lasting {approx}100 ps. The plasma under study was heated single-sided using a Gaussian 300-ps pulse of 438-nm light (3{omega} of the PALS iodine laser) at laser irradiances of 10{sup 13}-10{sup 14} W cm{sup -2}. Electron densities of 10{sup 20}-10{sup 22} cm{sup -3} and electron temperatures from 200 to 500 eV were probed at 0.5 or 1 ns after the peak of the heating pulse during the foil plasma expansion. A flat-field 1200 line mm{sup -1} variable-spaced grating spectrometer with a cooled charge-coupled device readout viewed the plasma in the forward direction at 30{sup o} with respect to the x-ray laser probe. We show results from plasmas generated from {approx}1 {micro}m thick targets of Al and polypropylene (C{sub 3}H{sub 6}). Numerical simulations of the Thomson scattering cross-sections will be presented. These simulations show electron peaks in addition to a narrow ion feature due to collective (incoherent) Thomson scattering. The electron features are shifted from the frequency of the scattered radiation approximately by the electron plasma frequency {+-}{omega}{sub pe} and scale as n{sub e}{sup 1/2}.

  15. Development of a YAG laser system for the edge Thomson scattering system in ITER.

    PubMed

    Hatae, T; Yatsuka, E; Hayashi, T; Yoshida, H; Ono, T; Kusama, Y

    2012-10-01

    A prototype YAG laser system for the edge Thomson scattering system in ITER has been newly developed. Performance of the laser amplifier was improved by using flow tubes made of samarium-doped glass; the small signal gain reached 20 at its maximum. As a result, an output energy of 7.66 J at 100 Hz was successfully achieved, and the performance exceeded the target performance (5 J, 100 Hz).

  16. Out-of-equilibrium conditions in x-ray Thomson scattering experiments

    NASA Astrophysics Data System (ADS)

    Faussurier, Gérald; Blancard, Christophe

    2015-06-01

    We study out-of-equilibrium conditions in recent x-ray Thomson scattering experiments performed in warm dense matter. We use an effective one-component plasma model to characterize the states in which electron and ion temperatures are different. An estimation of the ion temperature is obtained. This method is tested against two recent experiments. Strong out-of-equilibrium conditions are found.

  17. The preliminary design of the optical Thomson scattering diagnostic for the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Datte, P.; Ross, J. S.; Froula, D.; Galbraith, J.; Glenzer, S.; Hatch, B.; Kilkenny, J.; Landen, O.; Manuel, A. M.; Molander, W.; Montgomery, D.; Moody, J.; Swadling, G.; Weaver, J.; Vergel de Dios, G.; Vitalich, M.

    2016-05-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion programs. We report on the preliminary design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beamsplitter and gratings before the shot. A deep-UV probe beam (λ0 between 185-215 nm) will optimally collect Thomson scattered light from plasma densities of 5 x 1020 electrons/cm3 while a 3ω probe will optimally collect Thomson scattered light from plasma densities of 1 x 1019 electrons/cm3. We report the phase I design of a two phase design strategy. Phase I includes the OTS recording system to measure background levels at NIF and phase II will include the integration of a probe laser.

  18. The circuit of polychromator for Experimental Advanced Superconducting Tokamak edge Thomson scattering diagnostic

    SciTech Connect

    Zang, Qing; Zhao, Junyu; Chen, Hui; Li, Fengjuan; Hsieh, C. L.

    2013-09-15

    The detector circuit is the core component of filter polychromator which is used for scattering light analysis in Thomson scattering diagnostic, and is responsible for the precision and stability of a system. High signal-to-noise and stability are primary requirements for the diagnostic. Recently, an upgraded detector circuit for weak light detecting in Experimental Advanced Superconducting Tokamak (EAST) edge Thomson scattering system has been designed, which can be used for the measurement of large electron temperature (T{sub e}) gradient and low electron density (n{sub e}). In this new circuit, a thermoelectric-cooled avalanche photodiode with the aid circuit is involved for increasing stability and enhancing signal-to-noise ratio (SNR), especially the circuit will never be influenced by ambient temperature. These features are expected to improve the accuracy of EAST Thomson diagnostic dramatically. Related mechanical construction of the circuit is redesigned as well for heat-sinking and installation. All parameters are optimized, and SNR is dramatically improved. The number of minimum detectable photons is only 10.

  19. The circuit of polychromator for Experimental Advanced Superconducting Tokamak edge Thomson scattering diagnostic.

    PubMed

    Zang, Qing; Hsieh, C L; Zhao, Junyu; Chen, Hui; Li, Fengjuan

    2013-09-01

    The detector circuit is the core component of filter polychromator which is used for scattering light analysis in Thomson scattering diagnostic, and is responsible for the precision and stability of a system. High signal-to-noise and stability are primary requirements for the diagnostic. Recently, an upgraded detector circuit for weak light detecting in Experimental Advanced Superconducting Tokamak (EAST) edge Thomson scattering system has been designed, which can be used for the measurement of large electron temperature (T(e)) gradient and low electron density (n(e)). In this new circuit, a thermoelectric-cooled avalanche photodiode with the aid circuit is involved for increasing stability and enhancing signal-to-noise ratio (SNR), especially the circuit will never be influenced by ambient temperature. These features are expected to improve the accuracy of EAST Thomson diagnostic dramatically. Related mechanical construction of the circuit is redesigned as well for heat-sinking and installation. All parameters are optimized, and SNR is dramatically improved. The number of minimum detectable photons is only 10.

  20. Using collective x-ray Thomson scattering to measure temperature and density of warm dense matter

    SciTech Connect

    Doeppner, T; Davis, P F; Kritcher, A L; Landen, O L; Lee, H J; Regan, S P; Glenzer, S

    2009-07-29

    Collective x-ray Thomson scattering allows measuring plasmons, i.e electron plasma oscillations (Langmuir waves). This is manifest in the appearance of spectrally up- and down-shifted spectral features in addition to the Rayleigh signal. The ratio of the up- and down-shifted signals is directly related to detailed balance, allowing to determine the plasma temperature from first principles. The spectral shift of the plasmon signals is sensitive to temperature and electron density. We discuss the experimental considerations that have to be fulfilled to observe plasmon signals with x-ray Thomson scattering. As an example, we describe an experiment that used the Cl Ly-{alpha} x-ray line at 2.96 keV to measure collective Thomson scattering from solid beryllium, isochorically heated to 18 eV. Since temperature measurement based on detailed balance is based on first principles, this method is important to validate models that, for example, calculate the static ion-ion structure factor S{sub ii}(k).

  1. Intracavity Rayleigh/Mie Scattering for Multipoint, Two-Component Velocity Measurement

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.

    2006-01-01

    A simultaneous multi-point two-component Doppler velocimeter is described. The system uses two optical cavities: a Fabry-Perot etalon and an optical cavity for collecting and re-circulating the Rayleigh/Mie scattered light that is collected from the measurement volume in two parallel, but opposite directions. Single-pulse measurements of two orthogonal components of the velocity vector in a supersonic free jet were performed to demonstrate the technique. The re-circulation of the light rejected by the interferometer input mirror also increased the signal intensity by a factor of 3.5. 2005 Optical Society of America Interferometric Rayleigh scattering has previously been used for single-point velocity measurements in unseeded gas flow. However, this past work has generally been limited to probing with continuous-wave lasers resulting in time-averaged measurements of velocity. Multiple velocity components have been measured simultaneously by separate instruments.1,2 It has also been demonstrated that two orthogonal velocity components can be measured simultaneously at one point using one interferometer by reflecting back the probing laser beam, although this approach results in directional ambiguity of the flow velocity vector.3 This measurement ambiguity was removed by prior knowledge of the approximate magnitude and sign of the velocity components. Furthermore, it was shown that multiple points could be measured simultaneously with a Rayleigh scattering interferometric approach, but only one component of velocity was measured.4 Another method of performing multiple component velocity measurements with Rayleigh scattering uses a pair of cameras to image the flow, one of which views the flow through an iodine gas filter. This iodine-filter technique has the advantage of allowing high-resolution velocity imaging, but it generally has a lower dynamic range.

  2. X-ray Thomson Scattering from Dense Plasmas

    SciTech Connect

    Glenzer, S

    2007-05-14

    Advances in the development of laser-produced x-ray sources have enabled a new class of high-energy density physics experiments. Powerful narrow-bandwidth x rays penetrate through short-lived hot dense states of matter and probe the physical properties with spectrally resolved x-ray scattering. Experiments from isochorically-heated plasmas with electron densities in the range of solid density and above have been demonstrated allowing for the first time exploration of the microscopic properties of dense matter regime close to strongly-coupled and Fermi degenerate conditions. Backscatter measurements have accessed the non-collective Compton scattering regime, which provides accurate diagnostic information on the temperature, density and ionization states. The forward scattering spectrum has been shown to measure the collective plasmon oscillations. Besides extracting the standard plasma parameters, density and temperature, forward scattering yields new observables such as a direct measure of collisions, quantum effects and detailed balance. In this talk, we will discuss new results important for applications of this technique for novel experiments in a wide range of research areas such as inertial confinement fusion, radiation-hydrodynamics, material science, and laboratory astrophysics.

  3. K-(alpha) X-ray Thomson Scattering From Dense Plasmas

    SciTech Connect

    Kritcher, A L; Neumayer, P; Castor, J; Doppner, T; Falcone, R W; Landen, O L; Lee, H J; Lee, R W; Morse, E C; Ng, A; Pollaine, S; Price, D; Glenzer, S H

    2009-05-07

    Spectrally resolved Thomson scattering using ultra-fast K-{alpha} x-rays has measured the compression and heating of shocked compressed matter. The evolution and coalescence of two shock waves traveling through a solid density LiH target were characterized by the elastic scattering component. The density and temperature at shock coalescence, 2.2 eV and 1.7 x 10{sup 23}cm{sup -3}, were determined from the plasmon frequency shift and the relative intensity of the elastic and inelastic scattering features in the collective scattering regime. The observation of plasmon scattering at coalescence indicates a transition to the dense metallic state in LiH. The density and temperature regimes accessed in these experiments are relevant for inertial confinement fusion experiments and for the study of planetary formation.

  4. RF photoinjector development for a short-pulse, hard x-ray Thomson scattering source

    NASA Astrophysics Data System (ADS)

    Le Sage, G. P.; Anderson, S. G.; Cowan, T. E.; Crane, J. K.; Ditmire, T.; Rosenzweig, J. B.

    2001-05-01

    An important motivation in the development of the next generation x-ray light sources is to achieve picosecond and sub-ps pulses of hard x-rays for dynamic studies of a variety of physical, chemical, and biological processes. Present hard x-ray sources are either pulse-width or intensity limited, which allows ps-scale temporal resolution only for signal averaging of highly repetitive processes. A much faster and brighter hard x-ray source is being developed at LLNL, based on Thomson scattering of fs-laser pulses by a relativistic electron beam, which will enable x-ray characterization of the transient structure of a sample in a single shot. Experimental and diagnostic techniques relevant to the development of next generation sources including the Linac Coherent Light Source can be tested with the Thomson scattering hard x-ray source. This source will combine an RF photoinjector with a 100 MeV S-band linac. The photoinjector and linac also provide an ideal test-bed for examining space-charge induced emittance growth effects. A program of beam dynamics and diagnostic experiments are planned in parallel with Thomson source development. Our experimental progress and future plans will be discussed.

  5. Thomson Scattering Observation of Non-Maxwellian EEDF and the Effect of Local Electron Heating

    NASA Astrophysics Data System (ADS)

    Kono, A.; Funahashi, H.

    2001-10-01

    Laser Thomson scattering measurements were carried out to study electron energy distribution function (EEDF) of inductively coupled plasmas using C_4F_8/Ar and CF_4/Ar mixture gases. The plasma was produced using a one-turn coil antenna immersed in the plasma at a total pressure of 25 mTorr. A specially designed triple-grating spectrometer was used, which produces Thomson spectra on the output focal plane with the interfering Rayleigh and stray components highly suppressed; an ICCD camera operated in the photon-counting mode was used for multichannel detection of the spectrum. At a RF (13.56 MHz) input power of 300 W in the case of pure Ar plasma, EEDF was Maxwellian with an enectron density >10^12 cm-3. Upon mixing of C_4F8 as well as CF_4, decrease in the electron density and upward bend of the plot of the Thomson spectrum (energy vs. logarithmic scattering intensity) at energies around 5 eV was observed. The mechanism for producing this bend was studied via Monte-Carlo particle simulation. The results indicate that electron heating in a uniform electric field does not lead to upward bend; electrons should be heated locally near the antenna surface where the RF electric field is strong and cooled in other part of the plasma by inelastic collisions.

  6. Negative Ion Detection Using Laser Thomson Scattering Combined with Laser Photodetachment

    NASA Astrophysics Data System (ADS)

    Kono, A.; Ohno, J.; Funahashi, H.

    2001-10-01

    A purely optical technique for detecting negative ions in plasmas has been demonstrated where laser-photodetached electrons are detected via laser Thomson scattering. The technique allows one to obtain high spatial resolution (difficult to obtain using microwave techniques) without using a Langmuir probe. The plasma was irradiated by frequency-quadrupled (266nm) and frequency-doubled (532 nm) Nd:YAG laser beams originating from the same laser oscillator; the 266 nm beam causes photodetachment, while the 532 nm beam serves as the light source for Thomson scattering. It was so arranged that the 266 nm laser pulse irradiates the plasma 10 ns (>laser pulse width) earlier than the 532 nm laser pulse and, in the observation region, the focused thin 532 nm beam forms the coaxial core of the unfocused 266 nm beam. A specially designed triple-grating spectrometer was used, which produces Thomson spectra on the output focal plane with the interfering Rayleigh and stray components highly suppressed; an ICCD camera operated in the photon-counting mode was used for multichannel detection of the spectrum. Measurements for inductively coupled NF_3(5%)/Ar and SF_6(5%)/Ar plasmas at 25 mTorr with electron densities of ~ 10^11 cm-3 indicated that the negative ion density is of comparable magnitude to the electron density.

  7. Use of fast scopes to enable Thomson scattering measurement in presence of fluctuating plasma light.

    SciTech Connect

    McLean, H; Moller, J; Hill, D

    2004-04-19

    The addition of inexpensive high-speed oscilloscopes has enabled higher Te Thomson scattering measurements on the SSPX spheromak. Along with signal correlation techniques, the scopes allow new analyses based on the shape of the scattered laser pulse to discriminate against fluctuating background plasma light that often make gated-integrator measurements unreliable. A 1.4 J Nd:YAG laser at 1064 nm is the scattering source. Spatial locations are coupled by viewing optics and fibers to 4-wavelength-channel filter polychrometers. Ratios between the channels determine Te while summations of the channels determine density. Typically, the channel that provides scattered signal at higher Te is contaminated by fluctuating background light. Individual channels are correlated with either a modeled representation of the laser pulse or a noise-free stray light signal to extract channel amplitudes.

  8. Thomson scattering from near-solid density plasmas using soft x-ray free electron lasers

    SciTech Connect

    Holl, A; Bornath, T; Cao, L; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gregori, G; Laarmann, T; Meiwes-Broer, K H; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Thiele, R; Tiggesbaumker, J; Toleikis, S; Truong, N X; Tschentscher, T; Uschmann, I; Zastrau, U

    2006-11-21

    We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

  9. X-ray Thomson scattering measurements of temperature and density from multi-shocked CH capsules

    DOE PAGESBeta

    Fletcher, L. B.; Glenzer, S. H.; Kritcher, A.; Pak, A.; Ma, T.; Doppner, T.; Fortmann, C.; Divol, L.; Landen, O. L.; Vorberger, J.; et al

    2013-05-24

    Proof-of-principle measurements of the electron densities, temperatures, and ionization states of spherically compressed multi-shocked CH (polystyrene) capsules have been achieved using spectrally resolved x-ray Thomson scattering. A total energy of 13.5 kJ incident on target is used to compress a 70 μm thick CH shell above solid-mass density using three coalescing shocks. Separately, a laser-produced zinc He-α x-ray source at 9 keV delayed 200 ps-800 ps after maximum compression is used to probe the plasma in the non-collective scattering regime. The data show that x-ray Thomson scattering enables a complete description of the time-dependent hydrodynamic evolution of shock-compressed CH capsules,more » with a maximum measured density of ρ > 6 g cm–3. Additionally, the results demonstrate that accurate measurements of x-ray scattering from bound-free transitions in the CH plasma demonstrate strong evidence that continuum lowering is the primary ionization mechanism of carbon L-shell electrons.« less

  10. Design and implementation of a Thomson scattering diagnostic for the Compact Toroidal Hybrid

    NASA Astrophysics Data System (ADS)

    Traverso, P. J.; Maurer, D. A.; Hartwell, G. J.; Knowlton, S. F.; Archmiller, M. C.; Goforth, M. M.

    2013-10-01

    The Compact Toroidal Hybrid (CTH) experiment is investigating the avoidance of disruptions in ohmically driven torsaton plasmas as the ratio of vacuum transform to the total transform is changed. To better characterize these plasmas under this wide range of magnetic configurations, a new Thomson scattering diagnostic is being implemented to measure electron temperature and density profiles. These important internal profile measurements will be incorporated into the V3FIT code to enable better 3D equilibrium reconstruction. The Thomson scattering system uses a frequency doubled Continuum PL DLS 2 J Nd:YaG laser. The incident beam is passed vertically through an entrance Brewster window and a baffle system to minimize stray laser light. The beam exits through another Brewster window to an external beam dump. Polarization optics are planned to maximize the scattered light directed to the collection system for the specific scattering geometry of CTH. This work is supported by the USDoE under grant DE-FG02-00ER54610.

  11. X-ray Thomson scattering measurements of temperature and density from multi-shocked CH capsules

    SciTech Connect

    Fletcher, L. B.; Kritcher, A.; Pak, A.; Ma, T.; Döppner, T.; Divol, L.; Landen, O. L.; Glenzer, S. H.; Fortmann, C.; Vorberger, J.; Gericke, D. O.; Chapman, D. A.; Falcone, R. W.

    2013-05-15

    Proof-of-principle measurements of the electron densities, temperatures, and ionization states of spherically compressed multi-shocked CH (polystyrene) capsules have been achieved using spectrally resolved x-ray Thomson scattering. A total energy of 13.5 kJ incident on target is used to compress a 70 μm thick CH shell above solid-mass density using three coalescing shocks. Separately, a laser-produced zinc He-α x-ray source at 9 keV delayed 200 ps-800 ps after maximum compression is used to probe the plasma in the non-collective scattering regime. The data show that x-ray Thomson scattering enables a complete description of the time-dependent hydrodynamic evolution of shock-compressed CH capsules, with a maximum measured density of ρ > 6 g cm{sup −3}. In addition, the results demonstrate that accurate measurements of x-ray scattering from bound-free transitions in the CH plasma demonstrate strong evidence that continuum lowering is the primary ionization mechanism of carbon L-shell electrons.

  12. X-ray Thomson scattering measurements of temperature and density from multi-shocked CH capsules

    SciTech Connect

    Fletcher, L. B.; Glenzer, S. H.; Kritcher, A.; Pak, A.; Ma, T.; Doppner, T.; Fortmann, C.; Divol, L.; Landen, O. L.; Vorberger, J.; Chapman, D. A.; Gericke, D. O.; Falcone, R. W.

    2013-05-24

    Proof-of-principle measurements of the electron densities, temperatures, and ionization states of spherically compressed multi-shocked CH (polystyrene) capsules have been achieved using spectrally resolved x-ray Thomson scattering. A total energy of 13.5 kJ incident on target is used to compress a 70 μm thick CH shell above solid-mass density using three coalescing shocks. Separately, a laser-produced zinc He-α x-ray source at 9 keV delayed 200 ps-800 ps after maximum compression is used to probe the plasma in the non-collective scattering regime. The data show that x-ray Thomson scattering enables a complete description of the time-dependent hydrodynamic evolution of shock-compressed CH capsules, with a maximum measured density of ρ > 6 g cm–3. Additionally, the results demonstrate that accurate measurements of x-ray scattering from bound-free transitions in the CH plasma demonstrate strong evidence that continuum lowering is the primary ionization mechanism of carbon L-shell electrons.

  13. Fitting of the Thomson scattering density and temperature profiles on the COMPASS tokamak

    NASA Astrophysics Data System (ADS)

    Stefanikova, E.; Peterka, M.; Bohm, P.; Bilkova, P.; Aftanas, M.; Sos, M.; Urban, J.; Hron, M.; Panek, R.

    2016-11-01

    A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence on the actual magnetic configuration.

  14. Development of a Pulse-Burst Laser System for Fast Thomson Scattering on the MST RFP

    NASA Astrophysics Data System (ADS)

    den Hartog, D. J.

    2006-10-01

    A ``pulse-burst'' laser system is being developed for addition to the Thomson scattering diagnostic on the MST RFP. This laser will produce a burst of up to 200 approximately 1 J Q-switched pulses at repetition frequencies 5-250 kHz. The planned laser system will operate at 1064 nm and is based on existing Nd:YAG systems used to study fluid dynamics [Brian Thurow et al., Appl. Opt. 43, 5064 (2004)]. The burst train of laser pulses will enable the study of Te and ne dynamics in a single MST shot, and with ensembling, will enable correlation of Te and ne fluctuations with other fluctuating quantities.

  15. Ultrashort hard x-ray pulses generated by 90 degrees Thomson scattering

    SciTech Connect

    Chin, A.H.; Schoenlein, R.W.; Glover, T.E.

    1997-04-01

    Ultrashort x-ray pulses permit observation of fast structural dynamics in a variety of condensed matter systems. The authors have generated 300 femtosecond, 30 keV x-ray pulses by 90 degrees Thomson scattering between femtosecond laser pulses and relativistic electrons. The x-ray and laser pulses are synchronized on a femtosecond time scale, an important prerequisite for ultrafast pump-probe spectroscopy. Analysis of the x-ray beam properties also allows for electron bunch characterization on a femtosecond time scale.

  16. Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

    SciTech Connect

    Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R.

    2013-07-28

    We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed.

  17. Edge Thomson scattering diagnostic on COMPASS tokamak: Installation, calibration, operation, improvements

    SciTech Connect

    Bohm, P. Bilkova, P.; Melich, R.; Sestak, D.; Weinzettl, V.; Stockel, J.; Hron, M.; Panek, R.; Mikulin, O.; Scannell, R.; Naylor, G.; Frassinetti, L.; Fassina, A.; Walsh, M. J.

    2014-11-15

    The core Thomson scattering diagnostic (TS) on the COMPASS tokamak was put in operation and reported earlier. Implementation of edge TS, with spatial resolution along the laser beam up to ∼1/100 of the tokamak minor radius, is presented now. The procedure for spatial calibration and alignment of both core and edge systems is described. Several further upgrades of the TS system, like a triggering unit and piezo motor driven vacuum window shutter, are introduced as well. The edge TS system, together with the core TS, is now in routine operation and provides electron temperature and density profiles.

  18. Edge Thomson scattering diagnostic on COMPASS tokamak: installation, calibration, operation, improvements.

    PubMed

    Bohm, P; Aftanas, M; Bilkova, P; Stefanikova, E; Mikulin, O; Melich, R; Janky, F; Havlicek, J; Sestak, D; Weinzettl, V; Stockel, J; Hron, M; Panek, R; Scannell, R; Frassinetti, L; Fassina, A; Naylor, G; Walsh, M J

    2014-11-01

    The core Thomson scattering diagnostic (TS) on the COMPASS tokamak was put in operation and reported earlier. Implementation of edge TS, with spatial resolution along the laser beam up to ∼1/100 of the tokamak minor radius, is presented now. The procedure for spatial calibration and alignment of both core and edge systems is described. Several further upgrades of the TS system, like a triggering unit and piezo motor driven vacuum window shutter, are introduced as well. The edge TS system, together with the core TS, is now in routine operation and provides electron temperature and density profiles.

  19. First results from the Thomson scattering diagnostic on proto-MPEX

    NASA Astrophysics Data System (ADS)

    Biewer, T. M.; Meitner, S.; Rapp, J.; Ray, H.; Shaw, G.

    2016-11-01

    A Thomson scattering (TS) diagnostic has been successfully implemented on the prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory. The diagnostic collects the light scattered by plasma electrons and spectroscopically resolves the Doppler shift imparted to the light by the velocity of the electrons. The spread in velocities is proportional to the electron temperature, while the total number of photons is proportional to the electron density. TS is a technique used on many devices to measure the electron temperature (Te) and electron density (ne) of the plasma. A challenging aspect of the technique is to discriminate the small number of Thomson scattered photons against the large peak of background photons from the high-power laser used to probe the plasma. A variety of methods are used to mitigate the background photons in Proto-MPEX, including Brewster angled windows, viewing dumps, and light baffles. With these methods, first results were measured from argon plasmas in Proto-MPEX, indicating Te ˜ 2 eV and ne ˜ 1 × 1019 m-3. The configuration of the Proto-MPEX TS diagnostic will be described and plans for improvement will be given.

  20. X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser

    NASA Astrophysics Data System (ADS)

    Saunders, A. M.; Jenei, A.; Döppner, T.; Falcone, R. W.; Kraus, D.; Kritcher, A.; Landen, O. L.; Nilsen, J.; Swift, D.

    2016-11-01

    X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH2 targets on the OMEGA laser facility at the Laboratory for Laser Energetics in Rochester, NY. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Knowledge gained in this experiment shows a promising future for further XRTS measurements on indirectly driven OMEGA targets.

  1. Interpenetration and deflection phenomena in collisions between supersonic, magnetized, tungsten plasma flows diagnosed using high resolution optical Thomson scattering

    SciTech Connect

    Swadling, G. F.; Lebedev, S. V.; Burdiak, G.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Hall, G. N.; Suzuki-Vidal, F.; Bland, S.; Harvey-Thompson, A. J.; Rozmus, W.; Yuan, J.

    2015-07-15

    An optical Thomson scattering diagnostic has been used to investigate collisions between supersonic, magnetized plasma flows, in particular the transition from collisionless to collisional interaction dynamics. These flows were produced using tungsten wire array z-pinches, driven by the 1.4 MA 240 ns Magpie generator at Imperial College London. Measurements of the collective-mode Thomson scattering ion-feature clearly indicate that the ablation flows are interpenetrating at 100 ns (after current start), and this interpenetration continues until at least 140 ns. The Thomson spectrum at 150 ns shows a clear change in the dynamics of the stream interactions, transitioning towards a collisional, shock-like interaction of the streams near the axis. The Thomson scattering data also provide indirect evidence of the presence of a significant toroidal magnetic field embedded in the “precursor” plasma near the axis of the array over the period 100–140 ns; these observations are in agreement with previous measurements [Swadling et al., Phys. Rev. Lett. 113, 035003 (2014)]. The Thomson scattering measurements at 150 ns suggest that this magnetic field must collapse at around the time the dense precursor column begins to form.

  2. Collective Thomson scattering energetic particle diagnostic in high performance tokamaks. Final report

    SciTech Connect

    Cheung, P.Y.; Aamodt, R.E.; Russell, D.A.

    1997-07-08

    This report summarizes the work performed under DOE grant DE-FG03-95ER54334. Lodestar was an active participant in the low power Collective Thomson Scattering (CTS) diagnostic experiment at TFTR in collaboration with MIT. A simple and effective fitting technique was developed to extract key parameters from the scattered data. Utilizing this new technique, the concept of lower hybrid resonance scattering was adapted for a feasibility study of a low/medium power collective scattering diagnostic for ITER. The implementation and the testing of such a technique for actual parameter extraction using TFTR data, however, was severely limited due to experimental and instrumentation complications. Based on the studies the authors have performed up to date, it is believed that a combination of non-physics related effects such as multiple wall reflection of incident signal and spectral impurity problem o the gyrotron can account for the anomalous signal strength. A collaborative effort with GA was initiated and a feasibility study of developing and implementing a collective thomson scattering (CTS) diagnostic for the detection of energetic particles at DIII-D was completed. Specifically, the process of selecting an optimum receiver location for the diagnostic is discussed in detailed. Results presented here include detailed signal to noise calculations and ray-tracing studies. Critical physics issues and selection criteria are discussed and a procedure to detect anisotropic energetic ion temperatures is also outlined. Favorable results, obtained in the feasibility study, indicate that it should be possible to develop and implement a CTS diagnostic at DIII-D.

  3. Detecting non-maxwellian electron velocity distributions at JET by high resolution Thomson scattering.

    PubMed

    Beausang, K V; Prunty, S L; Scannell, R; Beurskens, M N; Walsh, M J; de la Luna, E

    2011-03-01

    The present work is motivated by a long standing discrepancy between the electron temperature measurements of Thomson scattering (TS) and electron cyclotron emission (ECE) diagnostics for plasmas with strong auxiliary heating observed at both JET and TFTR above 6–7 keV, where in some cases the ECE electron temperature measurements can be 15%–20% higher than the TS measurements. Recent analysis based on ECE results at JET has shown evidence of distortions to the Maxwellian electron velocity distribution and a correlation with the TS and ECE discrepancies has been suggested. In this paper, a technique to determine the presence of non-Maxwellian behavior using TS diagnostics is outlined. The difficulties and limitations of modern TS system designs to determine the electron velocity distribution are also discussed. It is demonstrated that small deviations such as those suggested by previous ECE analysis could be potentially detected, depending on the spectral layout of the TS polychromators. The spectral layout of the JET high resolution Thomson scattering system is such that it could be used to determine these deviations between 1 and 6 keV, and the results presented here indicate that no evidence of non-Maxwellian behavior is observed in this range. In this paper, a modification to the current polychromator design is proposed, allowing non-Maxwellian distortions to be detected up to at least 10 keV. PMID:21585113

  4. Detecting non-maxwellian electron velocity distributions at JET by high resolution Thomson scattering.

    PubMed

    Beausang, K V; Prunty, S L; Scannell, R; Beurskens, M N; Walsh, M J; de la Luna, E

    2011-03-01

    The present work is motivated by a long standing discrepancy between the electron temperature measurements of Thomson scattering (TS) and electron cyclotron emission (ECE) diagnostics for plasmas with strong auxiliary heating observed at both JET and TFTR above 6–7 keV, where in some cases the ECE electron temperature measurements can be 15%–20% higher than the TS measurements. Recent analysis based on ECE results at JET has shown evidence of distortions to the Maxwellian electron velocity distribution and a correlation with the TS and ECE discrepancies has been suggested. In this paper, a technique to determine the presence of non-Maxwellian behavior using TS diagnostics is outlined. The difficulties and limitations of modern TS system designs to determine the electron velocity distribution are also discussed. It is demonstrated that small deviations such as those suggested by previous ECE analysis could be potentially detected, depending on the spectral layout of the TS polychromators. The spectral layout of the JET high resolution Thomson scattering system is such that it could be used to determine these deviations between 1 and 6 keV, and the results presented here indicate that no evidence of non-Maxwellian behavior is observed in this range. In this paper, a modification to the current polychromator design is proposed, allowing non-Maxwellian distortions to be detected up to at least 10 keV.

  5. Conceptual Design Studies of the KSTAR Bay-Nm Cassette and Thomson Scattering Optics

    SciTech Connect

    Feder, R.; Ellis, R.; Johnson, D.; Park, H.; Lee, H. G.

    2005-09-26

    A Multi-Channel Thomson Scattering System viewing the edge and core of the KSTAR plasma will be installed at the mid-plane port Bay-N. An engineering design study was undertaken at PPPL in collaboration with the Korea Basic Science Institute (KBSI) to determine the optimal optics and cassette design. Design criteria included environmental, mechanical and optical factors. All of the optical design options have common design features; the Thomson Scattering laser, an in-vacuum shutter, a quartz heat shield and primary vacuum window, a set of optical elements and a fiber optic bundle. Neutron radiation damage was a major factor in the choice of competing lens-based and mirror-based optical designs. Both the mirror based design and the lens design are constrained by physical limits of the Bay-N cassette and interference with the Bay-N micro-wave launcher. The cassette will contain the optics and a rail system for maintenance of the optics.

  6. Development of laser beam injection system for the Edge Thomson Scattering (ETS) in ITER

    NASA Astrophysics Data System (ADS)

    Yatsuka, E.; Hatae, T.; Suitoh, S.; Ohara, M.; Hagita, K.; Inoue, K.; Bassan, M.; Walsh, M.; Itami, K.

    2016-01-01

    This paper focuses on the design and development of the laser injection system for the ITER Edge Thomson Scattering system (ETS). The ITER ETS achieves a temporal resolution of 100 Hz by firing two 50 Hz laser beams alternatively. The use of dual lasers enables us to perform the Thomson scattering measurements at a temporal resolution of 50 Hz in case that one of the laser systems stops functioning. A new type of beam combiner was developed to obtain a single beam that is collinear and fixed linearly polarized from two laser beams using a motor-driven rotating half-wave plate. The rotating half-wave plate method does not induce misalignment even if the rotating mechanism malfunctions. The combined beam is relayed from the diagnostic hall to the plasma using mirror optics and is absorbed at the beam dump integrated on the inner blanket. The beam alignment system was designed to direct the laser beam onto the center of the beam dump head. The beam position at the beam dump is monitored by four alignment laser beams which propagate parallel to the diagnostic Nd:YAG laser beam and imaging systems installed outside the diagnostic port.

  7. Electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Yoshikawa, M.; Ohta, K.; Wang, X.; Morishita, M.; Chikatsu, M.; Shima, Y.; Kohagura, J.; Yasuhara, R.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Ichimura, M.; Yamada, I.; Funaba, H.; Kawataha, K.; Minami, T.

    2015-08-01

    A multi-pass (MP) Thomson scattering (TS) system modeled on the GAMMA 10/PDX TS system was constructed for enhancing the Thomson scattered signals. The MPTS system has a polarization-based configuration with an image relaying system. The former MPTS system in GAMMA 10/PDX can measure only four passing signals. We changed the larger aperture polarization control device for improving the MP laser confinement and obtaining the over four passing MPTS signals. The integrated MPTS signals increased about 1.2 times larger than that in the former system.

  8. Temporal Evolution of Self-Modulated Laser Wakefields Measured by Coherent Thomson Scattering

    SciTech Connect

    Ting, A.; Krushelnick, K.; Moore, C.I.; Burris, H.R.; Esarey, E.; Krall, J.; Sprangle, P. |

    1996-12-01

    Coherent Thomson scattering of a picosecond probe laser was used to measure the time evolution of plasma wakefields produced by a high intensity laser pulse (7{times}10{sup 18} W/cm{sup 2}) in an underdense plasma ({ital n}{sub {ital e}}{approx_equal}10{sup 19} cm{sup {minus}3}) in the self-modulated laser wakefield accelerator configuration. Large amplitude plasma wakefields which lasted less than 5ps were observed to decay into ion acoustic waves. The time scales associated with these measurements were consistent with the effects of the modulational instability and the enhancement of scattered signal from plasma channel formation. {copyright} {ital 1996 The American Physical Society.}

  9. Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

    SciTech Connect

    Stejner, M. Nielsen, S.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Rasmussen, J.; Salewski, M.; Moseev, D.; Schubert, M.; Stober, J.; Wagner, D. H.

    2014-09-15

    Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.

  10. Initial results of the high resolution edge Thomson scattering upgrade at DIII-Da)

    NASA Astrophysics Data System (ADS)

    Eldon, D.; Bray, B. D.; Deterly, T. M.; Liu, C.; Watkins, M.; Groebner, R. J.; Leonard, A. W.; Osborne, T. H.; Snyder, P. B.; Boivin, R. L.; Tynan, G. R.

    2012-10-01

    Validation of models of pedestal structure is an important part of predicting pedestal height and performance in future tokamaks. The Thomson scattering diagnostic at DIII-D has been upgraded in support of validating these models. Spatial and temporal resolution, as well as signal to noise ratio, have all been specifically enhanced in the pedestal region. This region is now diagnosed by 20 view-chords with a spacing of 6 mm and a scattering length of just under 5 mm sampled at a nominal rate of 250 Hz. When mapped to the outboard midplane, this corresponds to ˜3 mm spacing. These measurements are being used to test critical gradient models, in which pedestal gradients increase in time until a threshold is reached. This paper will describe the specifications of the upgrade and present initial results of the system.

  11. Conceptual design of the collection optics for the edge Thomson scattering system in ITER.

    PubMed

    Yatsuka, E; Hatae, T; Suitoh, S; Aida, Y; Kusama, Y

    2010-10-01

    Neutron and gamma-ray irradiation complicates the design of the edge Thomson scattering (TS) system in ITER. The TS light is relayed through the relaying optics with labyrinth and fiber coupling optics. Electron density of 2×10(19) m(-3) is sufficient to measure T(e) and n(e) within a 10% and 5% margin of error, respectively, with a spatial resolution of 5 mm. This system can cover from 0.85 to 1 of the normalized minor radius. The time resolution is 10 ms, which is determined by the repetition rate of the laser device. A super-Gaussian is the ideal laser profile for the laser injection optics to avoid a breakdown of the filling gas used in density calibration through Raman scattering.

  12. Ultrahigh Brilliance Multi-MeV γ-Ray Beams from Nonlinear Relativistic Thomson Scattering.

    PubMed

    Sarri, G; Corvan, D J; Schumaker, W; Cole, J M; Di Piazza, A; Ahmed, H; Harvey, C; Keitel, C H; Krushelnick, K; Mangles, S P D; Najmudin, Z; Symes, D; Thomas, A G R; Yeung, M; Zhao, Z; Zepf, M

    2014-11-28

    We report on the generation of a narrow divergence (θ_{γ}<2.5  mrad), multi-MeV (E_{max}≈18  MeV) and ultrahigh peak brilliance (>1.8×10^{20}  photons s^{-1} mm^{-2}  mrad^{-2} 0.1% BW) γ-ray beam from the scattering of an ultrarelativistic laser-wakefield accelerated electron beam in the field of a relativistically intense laser (dimensionless amplitude a_{0}≈2). The spectrum of the generated γ-ray beam is measured, with MeV resolution, seamlessly from 6 to 18 MeV, giving clear evidence of the onset of nonlinear relativistic Thomson scattering. To the best of our knowledge, this photon source has the highest peak brilliance in the multi-MeV regime ever reported in the literature. PMID:25494074

  13. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited).

    PubMed

    Kubo, S; Nishiura, M; Tanaka, K; Shimozuma, T; Yoshimura, Y; Igami, H; Takahash, H; Mutoh, T; Tamura, N; Tatematsu, Y; Saito, T; Notake, T; Korsholm, S B; Meo, F; Nielsen, S K; Salewski, M; Stejner, M

    2010-10-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.

  14. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    SciTech Connect

    Nedanovska, E.; Nersisyan, G.; Lewis, C. L. S.; Riley, D.; Graham, W. G.; Morgan, T. J.; Hüwel, L.; Murakami, T.

    2015-01-07

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 10{sup 17 }cm{sup −3} to 9 × 10{sup 13 }cm{sup −3}, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t{sup 0.4} consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He{sub 2}{sup +} molecular ion play an important role.

  15. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    NASA Astrophysics Data System (ADS)

    Nedanovska, E.; Nersisyan, G.; Morgan, T. J.; Hüwel, L.; Murakami, T.; Lewis, C. L. S.; Riley, D.; Graham, W. G.

    2015-01-01

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 1017 cm-3 to 9 × 1013 cm-3, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ˜ t0.4 consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He2+ molecular ion play an important role.

  16. Simulation study of a photo-injector for brightness improvement in Thomson scattering X-ray source via ballistic bunching

    NASA Astrophysics Data System (ADS)

    Ding, Yun-Ze; Du, Ying-Chao; Zhang, Zhen; Huang, Wen-Hui

    2014-02-01

    Increasing the peak brightness is beneficial to various applications of the Thomson scattering X-ray source. A higher peak brightness of the scattered X-ray pulse demands a shorter scattering electron beam realized by beam compression in the electron beam-line. In this article, we study the possibility of compressing the electron beam in a typical S-band normal conducting photo-injector via ballistic bunching, through just adding a short RF linac section right behind the RF gun, so as to improve the peak brightness of the scattered x-ray pulse. Numerical optimization by ASTRA demonstrates that the peak current can increase from 50 A to > 300 A for a 500 pC, 10 ps FWHM electron pulse, while normalized transverse RMS emittance and RMS energy spread increases very little. Correspondingly, the peak brightness of the Thomson scattering X-ray source is estimated to increase about three times.

  17. Development of a laser diagnostic using Raman and Thomson scattering in atmospheric microplasma sources

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Adams, Steven

    2014-10-01

    A laser scattering system utilizing a triple grating spectrometer and a 266 nm ultraviolet laser has been developed in order to investigate Rayleigh, Raman, and Thomson scattering within atmospheric plasma sources. Such laser scattering interactions offer a non-invasive technique for investigating atmospheric microplasma sources, which have potential applications in remote optical sensing, materials processing, and environmental decontamination. In this work, laser scattering measurements were performed on atmospheric discharges composed of nitrogen and air. The laser signal was calibrated using a heated nitrogen vacuum cell held at atmospheric pressure. Preliminary temperature measurements were performed on a D.C. microdischarge operating in normal glow mode. This provides a non-thermal plasma in which the translational, rotational, vibrational and electron temperatures are not in equilibrium. All gas temperatures were calculated by fitting simulated scattering spectra to the experimental data obtained using the triple grating spectrometer. Measured temperatures were also compared with those obtained using standard optical emission spectroscopy methods. Special thanks to the NRC Research Associateship Program.

  18. The progress in development of edge tangential Thomson scattering system on HL-2A tokamak

    NASA Astrophysics Data System (ADS)

    Liu, C. H.; Huang, Y.; Wang, Y. Q.; Feng, Z.; Hou, Z. P.; Fu, B. Z.

    2016-11-01

    The edge tangential Thomson scattering system (ETTSS) was developed for the first time on a HL-2A tokamak. A Nd:YAG laser with a 1064 nm wavelength, 4 J energy, and 30 Hz repetition rate is employed on the ETTSS. The laser beam injects the plasma in the tangential direction on the mid-plane of the machine, and the angles between the laser injection direction and the scattered light collection direction are in the range from 157.5° to 162.8°. The scattered light collection optics with 0.21-0.47 magnification is utilized to collect the scattered light of measurement range from R = 1900 mm to 2100 mm (the normalized radius is from r/a = 0.625 to 1.125). Spatial resolution of the preliminary design could be up to Δr/a = 0.016. The measurement requirements could be achieved: 10 eV < Te < 1.5 keV, and 0.5 × 1019 m-3 < ne < 3 × 1019 m-3 with errors less than 15% and 10%, respectively.

  19. Status of the Thomson Scattering System Developed for Diagnostic Testing on the Helicon Plasma Experiment (HPX)*

    NASA Astrophysics Data System (ADS)

    Duke-Tinson, O.; James, R.; Nolan, S.; Page, E.; Paolino, R.; Romano, B.; Zuniga, J.; Schlank, C.; Lopez, M.; Karama, J.; Sherman, J.; Stutzman, B.

    2013-10-01

    HPX will utilize Electromagnetic Radiation Scattering to make internal plasma temperature and density point measurements. The United States Coast Guard Academy Plasma Laboratory's (CGAPL's) Thompson Scattering single spatial point system employs a 300 W CW YAG laser. We will use the internal temperature and density measurements in conjunction with the particle and spectral probes to track the plasmas transitions through the capacitive and inductive modes to ultimately reach the helicon mode. Once achieved, the system will be invaluable in making plasma quantitative temperature and density observations that will contribute to a comprehensive plasma profile. Most of the efforts thus far have been in the alignment and repair of the laser system. As this stage nears an end, efforts have begun to shift towards installing the aligned Thomson Scattering system (TS) into its permanent location, with mounted collection optics on HPX's top port. HPX will likely employ a polychrometer similar to the ones currently in use by HBTEP at Columbia University, for the spectral analysis of the scattered light. Data collected by the TS system will then be logged in real time by CGAPL's Data Acquisition (DAQ) system currently under construction. Further additions and progress of the TS alignment, installation, and calibration on HPX will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY12.

  20. X-ray Thomson Scattering using the Hybrid X-pinch X-ray Source

    NASA Astrophysics Data System (ADS)

    Hoyt, Cad; Pikuz, Sergei; Shelkovenko, Tania; Hammer, Dave

    2013-10-01

    Stringent photometric and bandwidth requirements have historically relegated X-ray Thomson scattering (XRTS) probe sources to high energy laser plasma sources or free electron lasers. Standard x-pinch configurations in which two or more fine wires cross and subtend an angle of about 30° forming an ``X'' between the anode and cathode of a pulsed power generatorcan produce extremely bright, subnanosecond bursts of continuum and line radiation from micron-scale sources. The hybrid x-pinch is a new configuration based on conical W-Cu alloy electrodes with a short 1-2 mm gap that is bridged by a fine wire resulting in an easier to load setup with improved performance characteristics. We explore the possibility of utilizing the hybid x-pinch as a novel XRTS probe source by examining certain spectral and temporal attributes of a range of materials in a hybrid x-pinch configuration on the XP (500 kA, 50 ns) and COBRA(1MA, 100ns) pulsed power generators. We find that a Ti hybrid x-pinch produces >1012 photons/sr in Ti He-alpha radiation and satisfies the noncollective scattering bandwidth requirement. Measurements of photon fluence, bandwidth and applicability to the relevant scattering regime and initial scattering results will be presented.

  1. Preliminary investigation of an atmospheric microplasma using Raman and Thomson laser scattering

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Adams, Steven

    2014-10-01

    A triple grating spectrometer system has been coupled with an ultraviolet laser at 266 nm for the purpose of investigating Rayleigh, Raman, and Thomson scattering within atmospheric plasma sources. Such laser interactions present a non-invasive diagnostic to investigate small scale atmospheric plasma sources, which have recently garnered interest for applications in remote optical sensing, materials processing, and environmental decontamination. In this work, the laser scatter and temperature relationship were calibrated with a heated nitrogen cell held at atmospheric pressure while subsequent scattering measurements were made in atmospheric discharges composed of nitrogen and air. An adjustable electrode configuration and dc circuit were assembled to produce a microdischarge operating in normal glow mode, thus providing a non-thermal plasma in which the translational, rotational, vibrational and electron temperatures are not in equilibrium. Preliminary results include measurements of these temperatures, which were calculated by fitting simulated scattering spectra to the experimental data obtained using the triple grating spectrometer. Measured temperatures were also compared with those obtained using standard optical emission spectroscopy methods. Special thanks to the NRC Research Associateship Program.

  2. Thomson scattering measurement of a collimated plasma jet generated by a high-power laser system

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Sakawa, Y.; Morita, T.; Yamaura, Y.; Kuramitsu, Y.; Moritaka, T.; Sano, T.; Shimoda, R.; Tomita, K.; Uchino, K.; Matsukiyo, S.; Mizuta, A.; Ohnishi, N.; Crowston, R.; Woolsey, N.; Doyle, H.; Gregori, G.; Koenig, M.; Michaut, C.; Pelka, A.; Yuan, D.; Li, Y.; Zhang, K.; Zhong, J.; Wang, F.; Takabe, H.

    2016-03-01

    One of the important and interesting problems in astrophysics and plasma physics is collimation of plasma jets. The collimation mechanism, which causes a plasma flow to propagate a long distance, has not been understood in detail. We have been investigating a model experiment to simulate astrophysical plasma jets with an external magnetic field [Nishio et al., EPJ. Web of Conferences 59, 15005 (2013)]. The experiment was performed by using Gekko XII HIPER laser system at Institute of Laser Engineering, Osaka University. We shot CH plane targets (3 mm × 3 mm × 10 μm) and observed rear-side plasma flows. A collimated plasma flow or plasma jet was generated by separating focal spots of laser beams. In this report, we measured plasma jet structure without an external magnetic field with shadowgraphy, and simultaneously measured the local parameters of the plasma jet, i.e., electron density, electron and ion temperatures, charge state, and drift velocity, with collective Thomson scattering.

  3. Characterization of heat transport and radiation hydrodynamics in collisional laser plasmas using collective Thomson scattering

    SciTech Connect

    Cameron, S.M.

    1993-10-01

    The author proposes using the collective Thomson scattering lineshape from ion acoustic waves to measure the spatial structure of local heat transport parameters and collisionality. Ion acoustic peak height asymmetry is used in conjunction with a recently developed model describing the effects of collisional and Landau damping contributions on the low-frequency electron density fluctuation spectrum to extract the relative electron drift. The local heat flux q{sub e} (proportional to drift) and the electron thermal conductivity {kappa}{sub e}{minus}q{sub e}/{gradient}T{sub e} would be inferred from experimentally determined temperature gradients {gradient}T{sub e}. Damping of the entropy wave component at zero mode frequency is shown to be an estimate of the ion thermal conductivity {kappa}{sub i}, and its visibility is a direct measure of the ion-ion mean free path {lambda}{sub ii}.

  4. Laser system for high resolution Thomson scattering diagnostics on the COMPASS tokamak

    SciTech Connect

    Bohm, P.; Sestak, D.; Bilkova, P.; Aftanas, M.; Weinzettl, V.; Hron, M.; Panek, R.; Dunstan, M. R.; Naylor, G.

    2010-10-15

    A new Thomson scattering diagnostic has been designed and is currently being installed on the COMPASS tokamak in IPP Prague in the Czech Republic. The requirements for this system are very stringent with approximately 3 mm spatial resolution at the plasma edge. A critical part of this diagnostic is the laser source. To achieve the specified parameters, a multilaser solution is utilized. Two 30 Hz 1.5 J Nd:YAG laser systems, used at the fundamental wavelength of 1064 nm, are located outside the tokamak area at a distance of 20 m from the tokamak. The design of the laser beam transport path is presented. The approach leading to a final choice of optimal focusing optics is given. As well as the beam path to the tokamak, a test path of the same optical length was built. Performance tests of the laser system carried out using the test path are described.

  5. Note: Multi-pass Thomson scattering measurement on the TST-2 spherical tokamak

    SciTech Connect

    Togashi, H. Ejiri, A.; Hiratsuka, J.; Nakamura, K.; Takase, Y.; Yamaguchi, T.; Furui, H.; Imamura, K.; Inada, T.; Kakuda, H.; Nakanishi, A.; Oosako, T.; Shinya, T.; Sonehara, M.; Tsuda, S.; Tsujii, N.; Wakatsuki, T.; Hasegawa, M.; Nagashima, Y.; Narihara, K.; and others

    2014-05-15

    In multi-pass Thomson scattering (TS) scheme, a laser pulse makes multiple round trips through the plasma, and the effective laser energy is enhanced, and we can increase the signal-to-noise ratio as a result. We have developed a coaxial optical cavity in which a laser pulse is confined, and we performed TS measurements using the coaxial cavity in tokamak plasmas for the first time. In the optical cavity, the laser energy attenuation was approximately 30% in each round trip, and we achieved a photon number gain of about 3 compared with that obtained in the first round trip. In addition, the temperature measurement accuracy was improved by accumulating the first three round trip waveforms.

  6. Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurementsa)

    NASA Astrophysics Data System (ADS)

    Moseev, D.; Meo, F.; Korsholm, S. B.; Bindslev, H.; Furtula, V.; Kantor, M.; Leipold, F.; Michelsen, P. K.; Nielsen, S. K.; Salewski, M.; Stejner, M.

    2012-10-01

    Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic on TEXTOR without a source of probing radiation in discharges with sawtooth oscillations, an elevation angle misalignment of 0.9° was found with an accuracy of 0.25°.

  7. Development of Thomson scattering system on Shenguang-III prototype laser facility

    SciTech Connect

    Gong, Tao; Li, Zhichao; Jiang, Xiaohua; Ding, Yongkun Yang, Dong; Wang, Zhebin; Wang, Fang; Li, Ping; Liu, Shenye; Jiang, Shaoen; Hu, Guangyue; Zhao, Bin; Zheng, Jian

    2015-02-15

    A Thomson scattering diagnostic system, using a 263 nm laser as the probe beam, is designed and implemented on Shenguang-III prototype laser facility. The probe beam is provided by an additional beam line completed recently. The diagnostic system allows simultaneous measurements of both ion feature and red-shifted electron feature from plasmas in a high-temperature (≥2 keV) and high-density (≥10{sup 21} cm{sup −3}) regime. Delicate design is made to satisfy the requirements for successful detection of the electron feature. High-quality ion feature spectra have already been diagnosed via this system in recent experiments with gas-filled hohlraums.

  8. Radial Electron Temperature and Density Measurements Using Thomson Scattering System in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Yoshikawa, M.; Ohta, K.; Wang, X.; Chikatsu, M.; Kohagura, J.; Shima, Y.; Sakamoto, M.; Imai, T.; Nakashima, Y.; Yasuhara, R.; Yamada, I.; Funaba, H.; Minami, T.

    2015-11-01

    A Thomson scattering (TS) system in GAMMA 10/PDX has been developed for the measurement of radial profiles of electron temperature and density in a single plasma and laser shot. The TS system has a large solid angle optical collection system and high-sensitivity signal detection system. The TS signals are obtained using four-channel high-speed digital oscilloscopes controlled by a Windows PC. We designed the acquisition program for six oscilloscopes to obtain 10-Hz TS signals in a single plasma shot, following which the time-dependent electron temperatures and densities can be determined. Moreover, in order to obtain larger TS signal intensity in the edge region, we added a second collection mirror. The radial electron temperatures and densities at six radial positions in GAMMA 10/PDX were successfully obtained.

  9. Numerical simulation for all-optical Thomson scattering X-ray source

    NASA Astrophysics Data System (ADS)

    Tan, Fang; Zhu, Bin; Han, Dan; Xin, Jian-Ting; Zhao, Zong-Qing; Cao, Lei-Feng; Gu, Yu-Qiu; Zhang, Bao-Han

    2014-03-01

    Energy spectra, angular distributions, and temporal profiles of the photons produced by an all-optical Thomson scattering X-ray source are explored through numerical simulations based on the parameters of the SILEX-I laser system (800 nm, 30 fs, 300 TW) and the previous wakefield acceleration experimental results. The simulation results show that X-ray pulses with a duration of 30 fs and an emission angle of 50 mrad can be produced from such a source. Using the optimized electron parameters, X-ray pulses with better directivity and narrower energy spectra can be obtained. Besides the electron parameters, the laser parameters such as the wavelength, pulse duration, and spot size also affect the X-ray yield, the angular distribution, and the maximum photon energy, except the X-ray pulse duration which is slightly changed for the case of ultrafast laser—electron interaction.

  10. Nonlinear relativistic single-electron Thomson scattering power spectrum for incoming laser of arbitrary intensity

    SciTech Connect

    Alvarez-Estrada, R. F.; Pastor, I.; Guasp, J.; Castejon, F.

    2012-06-15

    The classical nonlinear incoherent Thomson scattering power spectrum from a single relativistic electron with incoming laser radiation of any intensity, investigated numerically by the present authors in a previous publication, displayed both an approximate quadratic behavior in frequency and a redshift of the power spectrum for high intensity incoming radiation. The present work is devoted to justify, in a more general setup, those numerical findings. Those justifications are reinforced by extending suitably analytical approaches, as developed by other authors. Moreover, our analytical treatment exhibits differences between the Doppler-like frequencies for linear and circular polarization of the incoming radiation. Those differences depend nonlinearly on the laser intensity and on the electron initial velocity and do not appear to have been displayed by previous authors. Those Doppler-like frequencies and their differences are validated by new Monte Carlo computations beyond our previuos ones and reported here.

  11. CMB B-mode polarization from Thomson scattering in the local universe

    SciTech Connect

    Hirata, Christopher M.; Loeb, Abraham; Afshordi, Niayesh

    2005-03-15

    The polarization of the cosmic microwave background (CMB) is widely recognized as a potential source of information about primordial gravitational waves. The gravitational wave contribution can be separated from the dominant CMB polarization created by density perturbations at the times of recombination and reionization because it generates both E and B polarization modes, whereas the density perturbations create only E polarization. The limits of our ability to measure gravitational waves are thus determined by statistical and systematic errors from CMB experiments, foregrounds, and nonlinear evolution effects such as gravitational lensing of the CMB. Usually it is assumed that most foregrounds can be removed because of their frequency dependence, however Thomson scattering of the CMB quadrupole by electrons in the Galaxy or nearby structures shares the blackbody frequency dependence of the CMB. If the optical depth from these nearby electrons is anisotropic, the polarization generated can include B modes even if no tensor perturbations are present. We estimate this effect for the Galactic disk and nearby extragalactic structures, and find that it contributes to the B polarization at the level of {approx}(1-2)x10{sup -4} {mu}K per logarithmic interval in multipole l for l<30. This is well below the detectability level even for a future CMB polarization satellite and hence is negligible. Depending on its structure and extent, the Galactic corona may be a source of B-modes comparable to the residual large-scale lensing B-mode after the latter has been cleaned using lensing reconstruction techniques. For an extremely ambitious post-Planck CMB experiment, Thomson scattering in the Galactic corona is thus a potential contaminant of the gravitational wave signal; conversely, if the other foregrounds can be cleaned out, such an experiment might be able to constrain models of the corona.

  12. Thomson scattering measurements of ion interpenetration in cylindrically converging, supersonic magnetized plasma flows

    NASA Astrophysics Data System (ADS)

    Swadling, George

    2015-11-01

    Ion interpenetration driven by high velocity plasma collisions is an important phenomenon in high energy density environments such as the interiors of ICF vacuum hohlraums and fast z-pinches. The presence of magnetic fields frozen into these colliding flows further complicates the interaction dynamics. This talk focuses on an experimental investigation of ion interpenetration in collisions between cylindrically convergent, supersonic, magnetized flows (M ~10, Vflow ~ 100km/s, ni ~ 1017cm-3) . The flows used in this study were plasma ablation streams produced by tungsten wire array z-pinches, driven by the 1.4MA, 240ns Magpie facility at Imperial College, and diagnosed using a combination of optical Thomson scattering, Faraday rotation and interferometry. Optical Thomson scattering (TS) provides time-resolved measurements of local flow velocity and plasma temperature across multiple (7 to 14) spatial positions. TS spectra are recorded simultaneously from multiple directions with respect to the probing beam, resulting in separate measurements of the rates of transverse diffusion and slowing-down of the ion velocity distribution. The measurements demonstrate flow interpenetration through the array axis at early time, and also show an axial deflection of the ions towards the anode. This deflection is induced by a toroidal magnetic field (~ 10T), frozen into the plasma that accumulates near the axis. Measurements obtained later in time show a change in the dynamics of the stream interactions, transitioning towards a collisional, shock-like interaction of the streams, and rapid radial collapse of the magnetized plasma column. The quantitative nature of the spatial profiles of the density, flow velocities and ion temperatures measured in these experiments will allow detailed verification of MHD and PIC codes used by the HEDP community. Work Supported by EPSRC (Grant No. EP/G001324/1), DOE (Cooperative Agreement Nos. DE-F03-02NA00057 & DE-SC-0001063) & Sandia National

  13. CMB B-mode polarization from Thomson scattering in the local universe

    NASA Astrophysics Data System (ADS)

    Hirata, Christopher M.; Loeb, Abraham; Afshordi, Niayesh

    2005-03-01

    The polarization of the cosmic microwave background (CMB) is widely recognized as a potential source of information about primordial gravitational waves. The gravitational wave contribution can be separated from the dominant CMB polarization created by density perturbations at the times of recombination and reionization because it generates both E and B polarization modes, whereas the density perturbations create only E polarization. The limits of our ability to measure gravitational waves are thus determined by statistical and systematic errors from CMB experiments, foregrounds, and nonlinear evolution effects such as gravitational lensing of the CMB. Usually it is assumed that most foregrounds can be removed because of their frequency dependence, however Thomson scattering of the CMB quadrupole by electrons in the Galaxy or nearby structures shares the blackbody frequency dependence of the CMB. If the optical depth from these nearby electrons is anisotropic, the polarization generated can include B modes even if no tensor perturbations are present. We estimate this effect for the Galactic disk and nearby extragalactic structures, and find that it contributes to the B polarization at the level of ˜(1 2)×10-4 μK per logarithmic interval in multipole ℓ for ℓ<30. This is well below the detectability level even for a future CMB polarization satellite and hence is negligible. Depending on its structure and extent, the Galactic corona may be a source of B-modes comparable to the residual large-scale lensing B-mode after the latter has been cleaned using lensing reconstruction techniques. For an extremely ambitious post-Planck CMB experiment, Thomson scattering in the Galactic corona is thus a potential contaminant of the gravitational wave signal; conversely, if the other foregrounds can be cleaned out, such an experiment might be able to constrain models of the corona.

  14. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  15. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

    PubMed

    Johnson, W R; Nilsen, J

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  16. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited)

    SciTech Connect

    Meo, F.; Bindslev, H.; Korsholm, S. B.; Furtula, V.; Leipold, F.; Michelsen, P. K.; Nielsen, S. K.; Salewski, M.; Leuterer, F.; Woskov, P.; Stober, J.; Wagner, D.

    2008-10-15

    The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen.

  17. Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited).

    PubMed

    Meo, F; Bindslev, H; Korsholm, S B; Furtula, V; Leuterer, F; Leipold, F; Michelsen, P K; Nielsen, S K; Salewski, M; Stober, J; Wagner, D; Woskov, P

    2008-10-01

    The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen.

  18. Diagnosing Pulsed Power Produced Plasmas with X-ray Thomson Scattering at the Nevada Terawatt Facility

    NASA Astrophysics Data System (ADS)

    Valenzuela, J. C.; Krauland, C.; Mariscal, D.; Krasheninnikov, I.; Beg, F. N.; Wiewior, P.; Covington, A.; Presura, R.; Ma, T.; Niemann, C.; Mabey, P.; Gregori, G.

    2015-11-01

    We present experimental results on X-ray Thomson scattering (XRTS) at the Nevada Terawatt Facility (NTF) to study current driven plasmas. Using the Leopard laser, ~ 30 J and pulse width of 0.8 ns, we generated He- α emission (4.75 keV) from a thin Ti foil. Initial parameter scans showed that the optimum intensity is ~ 1015W/cm2 with a foil thickness of 2 μm for forward X-ray production. Bandwidth measurements of the source, using a HAPG crystal in the Von Hamos configuration, were found to be ΔE/E ~ 0.01. Giving the scattering angle of our experimental setup of 129 degrees and X-ray probing energy, the non-collective regime was accessed. The ZEBRA load was a 3 mm wide, 500 μm thick, and 10 mm long graphite foil, placed at one of the six current return posts. Estimates of the plasma temperature, density and ionization state were made by fitting the scattering spectra with dynamic structure factor calculations based on the random phase approximation for the treatment of charged particle coupling. The work was partially funded by the Department of Energy grant number DE-NA0001995.

  19. Demonstration of imaging X-ray Thomson scattering on OMEGA EP

    NASA Astrophysics Data System (ADS)

    Belancourt, Patrick X.; Theobald, Wolfgang; Keiter, Paul A.; Collins, Tim J. B.; Bonino, Mark J.; Kozlowski, Pawel M.; Regan, Sean P.; Drake, R. Paul

    2016-11-01

    Foams are a common material for high-energy-density physics experiments because of low, tunable densities, and being machinable. Simulating these experiments can be difficult because the equation of state is largely unknown for shocked foams. The focus of this experiment was to develop an x-ray scattering platform for measuring the equation of state of shocked foams on OMEGA EP. The foam used in this experiment is resorcinol formaldehyde with an initial density of 0.34 g/cm3. One long-pulse (10 ns) beam drives a shock into the foam, while the remaining three UV beams with a 2 ns square pulse irradiate a nickel foil to create the x-ray backlighter. The primary diagnostic for this platform, the imaging x-ray Thomson spectrometer, spectrally resolves the scattered x-ray beam while imaging in one spatial dimension. Ray tracing analysis of the density profile gives a compression of 3 ± 1 with a shock speed of 39 ± 6 km/s. Analysis of the scattered x-ray spectra gives an upper bound temperature of 20 eV.

  20. First results and analysis of collective Thomson scattering (CTS) fast ion distribution measurements on ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Meo, F.; Stejner, M.; Salewski, M.; Bindslev, H.; Eich, T.; Furtula, V.; Korsholm, S. B.; Leuterer, F.; Leipold, F.; Michelsen, P. K.; Moseev, D.; Nielsen, S. K.; Reiter, B.; Stober, J.; Wagner, D.; Woskov, P.; ASDEX Upgrade Team

    2010-05-01

    Experimental knowledge of the fast ion physics in magnetically confined plasmas is essential. The collective Thomson scattering (CTS) diagnostic is capable of measuring localized 1D ion velocity distributions and anisotropies dependent on the angle to the magnetic field. The CTS installed at ASDEX-Upgrade (AUG) uses mm-waves generated by the 1 MW dual frequency gyrotron. The successful commissioning the CTS at AUG enabled first scattering experiments and the consequent milestone of first fast ion distribution measurements on AUG presented in this paper. The first fast ion distribution results have already uncovered some physics of confined fast ions at the plasma centre with off-axis neutral beam heating. However, CTS experiments on AUG H-mode plasmas have also uncovered some unexpected signals not related to scattering that required additional analysis and treatment of the data. These secondary emission signals are generated from the plasma-gyrotron interaction therefore contain additional physics. Despite their existence that complicate the fast ion analysis, they do not prevent the diagnostic's capability to infer the fast ion distribution function on AUG.

  1. Perspectives of millimeter-wave collective Thomson scattering of confined alphas in ignited plasmas

    SciTech Connect

    Tartari, U.; Nowak, S.; Ramponi, G.

    1996-11-01

    Collective Thomson scattering on alpha density fluctuations in ignited plasma regimes is investigated with reference to a promising candidate source as the mm-wave gyrotron and a representative ITER-like plasma regime. It is shown that a number of intrinsic limitations characterize each of the equatorial scattering geometries selected as more promising, namely a backscattering geometry at {ital f}{sub 0}=80 GHz and two similar quasiorthogonal geometries at {ital f}{sub 0}=180 GHz. A lack of spatial resolution typical of the former geometry has to be contrasted with a significant limitation in plasma access typical of the remaining geometries. Other relevant differences concern the requirements in terms of gyrotron power, acceptable stray radiation levels, etc. Special emphasis is given in the work to a discussion of ECE noise, on which the feasibility itself of the alpha collective scattering diagnostics at mm-waves largely depends in the plasma regimes considered. {copyright} {ital 1996 American Institute of Physics.}

  2. First results of electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10

    SciTech Connect

    Yoshikawa, M. Nagasu, K.; Shimamura, Y.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Ichimura, M.; Yasuhara, R.; Yamada, I.; Funaba, H.; Kawahata, K.; Minami, T.

    2014-11-15

    A multi-pass Thomson scattering (TS) has the advantage of enhancing scattered signals. We constructed a multi-pass TS system for a polarisation-based system and an image relaying system modelled on the GAMMA 10 TS system. We undertook Raman scattering experiments both for the multi-pass setting and for checking the optical components. Moreover, we applied the system to the electron temperature measurements in the GAMMA 10 plasma for the first time. The integrated scattering signal was magnified by approximately three times by using the multi-pass TS system with four passes. The electron temperature measurement accuracy is improved by using this multi-pass system.

  3. Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D

    NASA Astrophysics Data System (ADS)

    Brookman, M. W.; Austin, M. E.; McLean, A. G.; Carlstrom, T. N.; Hyatt, A. W.; Lohr, J.

    2016-11-01

    Thomson scattering produces ne profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation ne ∝ ITS, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the ne calibration is adjusted against an absolute ne from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson ne from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as "ECH pump-out" generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.

  4. The upgrade of the Thomson scattering system for measurement on the C-2/C-2U devices

    NASA Astrophysics Data System (ADS)

    Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C.

    2016-11-01

    The C-2/C-2U Thomson scattering system has been substantially upgraded during the latter phase of C-2/C-2U program. A Rayleigh channel has been added to each of the three polychromators of the C-2/C-2U Thomson scattering system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added Rayleigh channel, the absolute intensity response of the system is calibrated with Rayleigh scattering in argon gas from 0.1 to 4 Torr, where the Rayleigh scattering signal is comparable to the Thomson scattering signal at electron densities from 1 × 1013 to 4 × 1014 cm-3. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.

  5. Periodicity property of relativistic Thomson scattering with application to exact calculations of angular and spectral distributions of the scattered field

    SciTech Connect

    Popa, Alexandru

    2011-08-15

    We prove that the analytical expression of the intensity of the relativistic Thomson scattered field for a system composed of an electron interacting with a plane electromagnetic field can be written in the form of a composite periodic function of only one variable, that is, the phase of the incident field. This property is proved without using any approximation in the most general case in which the field is elliptically polarized, the initial phase of the incident field and the initial velocity of the electron are taken into consideration, and the direction in which the radiation is scattered is arbitrary. This property leads to an exact method for calculating the angular and spectral distributions of the scattered field, which reveals a series of physical details of these distributions, such as their dependence on the components of the initial electron velocity. Since the phase of the field is a relativistic invariant, it follows that the periodicity property is also valid when the analysis is made in the inertial system in which the initial velocity of the electron is zero in the case of interactions between very intense electromagnetic fields and relativistic electrons. Consequently, the calculation method can be used for the evaluation of properties of backscattered hard radiations generated by this type of interaction. The theoretical evaluations presented in this paper are in good agreement with the experimental data from literature.

  6. Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures less than 1 keV

    SciTech Connect

    Ross, James Steven

    2010-01-01

    Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (Te < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 1020cm-3 are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.

  7. Design of the Collective Thomson scattering (CTS) system by using 170-GHz gyrotron in the KSTAR

    NASA Astrophysics Data System (ADS)

    Park, Min; Kim, Sun-Ho; Kim, Sung-Kyu; Lee, Kyu-Dong; Wang, Son-Jong

    2014-10-01

    The physics of energetic ions is one of the primary subjects to be understood toward the realization of a nuclear fusion power plant. Collective Thomson scattering (CTS) offers the possibility to diagnose the fast ions and the alpha particles in burning plasmas. Spatially- and temporally-resolved one-dimensional velocity distributions of the fast ions can be obtained from the scattered radiation with fewer geometric constraints by utilizing millimeter waves from a high-power gyrotron as a probe beam. We studied the feasibility of CTS fast-ion measurements in the KSTAR by calculating the spectral density functions. Based on that, we suggest a design for the CTS system that uses the currently-operating 170-GHz gyrotron for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) in the KSTAR. The CTS system is presented as two subsystems: the antenna system and the heterodyne receiver system. The design procedure for an off-axis ellipsoidal mirror is described, and the CTS system requirements are discussed.

  8. The design of the optical Thomson scattering diagnostic for the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Datte, P. S.; Ross, J. S.; Froula, D. H.; Daub, K. D.; Galbraith, J.; Glenzer, S.; Hatch, B.; Katz, J.; Kilkenny, J.; Landen, O.; Manha, D.; Manuel, A. M.; Molander, W.; Montgomery, D.; Moody, J.; Swadling, G. F.; Weaver, J.

    2016-11-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ0-210 nm) will be used to optimize the scattered signal for plasma densities of 5 × 1020 electrons/cm3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 1019 electrons/cm3. We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.

  9. A low-cost multichannel Thomson scattering system for CDX-U

    SciTech Connect

    Munsat, T.; LeBlanc, B.

    1999-01-01

    A multichannel Thomson scattering system has been developed for the CDX-U spherical torus. The system is designed for 10thinspeV{lt}T{sub e}{lt}400thinspeV, n{sub e}{gt}10{sup 18}thinspm{sup {minus}3}, which includes typical and predicted central and edge conditions in CDX-U. The system uses two laser passes to double the scattered photons from a 5 J ruby laser. The beam path is vertical through the {approximately}66 cm (elongated) diameter of the plasma and is movable in the major-radial direction, enabling coverage of nearly 70{percent} of the major-radial plasma extent. Twelve channels over the vertical minor radius provide {approximately}2.5 cm spatial resolution. The main collecting lens, located 45 cm from the laser beamline, provides high solid angle ({Delta}{Omega}{approximately}0.01) light collection using a 15 cm diam lens. The system makes maximum usage of an optically fast (f/1.8) compact imaging spectrometer. An intensified charge coupled device with a GaAs photocathode provides quantum efficiency of {approximately}20{percent} at 6943 {Angstrom}. The combination of plasma access, multiple beam passes, high-throughput spectrometer, and high quantum efficiency detector provide for very high total photon statistics in a relatively simple and inexpensive system.

  10. Updates on the Optical Emission Spectroscopy and Thomson Scattering Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Duke-Tinson, Omar; Karama, Jackson; Azzari, Phillip; Royce, James; Page, Eric; Schlank, Carter; Sherman, Justin; Stutzman, Brooke; Zuniga, Jonathan

    2014-10-01

    HPX at the Coast Guard Academy Plasma Laboratory (CGAPL) have set up spectral probes to verify plasma mode transitions to the W-mode. These optical probes utilize movable filters, and ccd cameras to gather data at selected spectral frequency bands. Raw data collected will be used to measure the plasma's relative density, temperature, structure, and behavior during experiments. Direct measurements of the plasma's properties can be determined through modeling and by comparison with the state transition tables, using Optical Emission Spectroscopy (OES). The spectral probes will take advantage of HPX's magnetic field structure to define and measure the plasma's radiation temp as a function of time and space. In addition, the Thomson Scattering (TS) device will measure internal temperature and density data as the HPX plasma transitions through capacitive and inductive modes while developing into helicon plasma. Currently CGAPL is focused on building its laser beam transport and scattered light collection optical systems. Recently, HPX has acquired an Andor ICCD spectrometer for the spectral analysis. Data collected by the TS system will be logged in real time by CGAPL's Data Acquisition (DAQ) system with LabView remote access. Further progress on HPX will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY13.

  11. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade.

    PubMed

    Furtula, V; Salewski, M; Leipold, F; Michelsen, P K; Korsholm, S B; Meo, F; Moseev, D; Nielsen, S K; Stejner, M; Johansen, T

    2012-01-01

    Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements.

  12. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade

    SciTech Connect

    Furtula, V.; Salewski, M.; Leipold, F.; Michelsen, P. K.; Korsholm, S. B.; Meo, F.; Moseev, D.; Nielsen, S. K.; Stejner, M.; Johansen, T.

    2012-01-15

    Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements.

  13. Upgrades to improve the usability, reliability, and spectral range of the MST Thomson scattering diagnostic

    NASA Astrophysics Data System (ADS)

    Kubala, S. Z.; Borchardt, M. T.; Den Hartog, D. J.; Holly, D. J.; Jacobson, C. M.; Morton, L. A.; Young, W. C.

    2016-11-01

    The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) have been added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable directed electron flow measurements. A supercontinuum (SC) pulsed white light source has replaced the tungsten halogen lamp previously used for spectral calibration of the polychromators. The SC source combines substantial brightness produced in nanosecond pulses with a spectrum that covers the entire range of the polychromators.

  14. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Furtula, V.; Salewski, M.; Leipold, F.; Michelsen, P. K.; Korsholm, S. B.; Meo, F.; Moseev, D.; Nielsen, S. K.; Stejner, M.; Johansen, T.

    2012-01-01

    Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements

  15. Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor.

    PubMed

    Leipold, F; Furtula, V; Salewski, M; Bindslev, H; Korsholm, S B; Meo, F; Michelsen, P K; Moseev, D; Nielsen, S K; Stejner, M

    2009-09-01

    Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic using gyrotrons operated at 60 GHz will meet the requirements for spatially and temporally resolved measurements of the velocity distributions of confined fast alphas in ITER by evaluating the scattered radiation (CTS signal). While a receiver antenna on the low field side of the tokamak, resolving near perpendicular (to the magnetic field) velocity components, has been enabled, an additional antenna on the high field side (HFS) would enable measurements of near parallel (to the magnetic field) velocity components. A compact design solution for the proposed mirror system on the HFS is presented. The HFS CTS antenna is located behind the blankets and views the plasma through the gap between two blanket modules. The viewing gap has been modified to dimensions 30x500 mm(2) to optimize the CTS signal. A 1:1 mock-up of the HFS mirror system was built. Measurements of the beam characteristics for millimeter-waves at 60 GHz used in the mock-up agree well with the modeling.

  16. Measuring the Ion Temperature in X-ray Thomson Scattering Experiments of Warm Dense Matter (WDM)

    NASA Astrophysics Data System (ADS)

    Benage, John; Murillo, Michael

    2010-11-01

    X-ray Thomson scattering offers an unprecedented method for measuring the properties of dense plasmas, including the electron temperature, the ionization state, and the free electron density. More difficult to extract from the measurements is the ion temperature. To date, the ion temperature has been extracted from experimental data using the diffractive portion of the scattering signal, which is a measure of the ion static structure S(k); thus, an accurate measurement requires an accurate model for S(k). Here, we compare models for S(k) in WDM and find that their differences are significant. Because of the paucity of WDM data, we use very accurate liquid metal data as a proxy. No current model reproduces all of the liquid metal data, although some are better for certain metals than others. We also introduce a new model that employs an effective screening length, obtained from the finite-temperature Lindhard response, in a modified hypernetted chain approach. This approach is superior to the previous approaches and we expect it will be even better for WDM.

  17. Electron heating and confinemet measurements in EBT-S using Thomson scattering

    SciTech Connect

    Bighel, L.; Cobble, J.A.

    1980-09-01

    Thomson scattering of ruby laser light was used to measure electron temperatures and densities in the ELMO Bumpy Torus-Scale (EBT-S) at Oak Ridge National Laboratory. The measurements were made primarily during May 1980, although some were taken during January 1980. The scattering system, which was designed for very low electron density measurements, features a 14-J ruby laser, a high-throughput spectrometer, and 15% quantum efficiency photomultipliers. The measured electron densities lie in the range 5 X 10/sup 11/ cm/sup -3/ to 2.2 X 10/sup 12/ cm/sup -3/ with electron temperatures from 50 to 500 eV. The radial profiles of T/sub e/ and n/sub e/ are reasonably flat over an 8-cm region from the plasma center outward. The dependence of T/sub e/ and n/sub e/ on microwave power input and on background pressure is discussed. The electron data are used to derive approximate values of the energy confinement time.

  18. Design of a CO{sub 2}-laser Thomson scattering ion-tail diagnostic for Alcator C-Mod

    SciTech Connect

    Richards, R.K.; Hutchinson, D.P.; Ma, C.H.

    1994-09-01

    A CO{sub 2}-laser Thomson scattering diagnostic has been designed for the measurement of the ICRH-produced ion tail on Alcator C-Mod. The plasma parameters and port access require that the detection of scattered radiation be made at small angles, typically one degree or less. The receiver system consists of five heterodyne detectors and the source laser produces an energy of 10 Joules per pulse with a 1 to 5 microsecond pulse length. The scattering system is currently being installed on the Alcator C-Mod experiment. Details of the diagnostic, calculations of the expected measurements, and application of the diagnostic for ITER are presented.

  19. High time resolved electron temperature measurements by using the multi-pass Thomson scattering system in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Masayuki; Yasuhara, Ryo; Ohta, Koichi; Chikatsu, Masayuki; Shima, Yoriko; Kohagura, Junko; Sakamoto, Mizuki; Nakashima, Yousuke; Imai, Tsuyoshi; Ichimura, Makoto; Yamada, Ichihiro; Funaba, Hisamichi; Minami, Takashi

    2016-11-01

    High time resolved electron temperature measurements are useful for fluctuation study. A multi-pass Thomson scattering (MPTS) system is proposed for the improvement of both increasing the TS signal intensity and time resolution. The MPTS system in GAMMA 10/PDX has been constructed for enhancing the Thomson scattered signals for the improvement of measurement accuracy. The MPTS system has a polarization-based configuration with an image relaying system. We optimized the image relaying optics for improving the multi-pass laser confinement and obtaining the stable MPTS signals over ten passing TS signals. The integrated MPTS signals increased about five times larger than that in the single pass system. Finally, time dependent electron temperatures were obtained in MHz sampling.

  20. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging.

    PubMed

    Kobayashi, T; Ida, K; Itoh, K; Yoshinuma, M; Moon, C; Inagaki, S; Yamada, I; Funaba, H; Yasuhara, R; Tsuchiya, H; Ohdachi, S; Yoshimura, Y; Igami, H; Shimozuma, T; Kubo, S; Tsujimura, T I

    2016-04-01

    This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

  1. Influence of local-field corrections on Thomson scattering in collision-dominated two-component plasmas

    SciTech Connect

    Fortmann, Carsten; Wierling, August; Roepke, Gerd

    2010-02-15

    The dynamic structure factor, which determines the Thomson scattering spectrum, is calculated via an extended Mermin approach. It incorporates the dynamical collision frequency as well as the local-field correction factor. This allows to study systematically the impact of electron-ion collisions as well as electron-electron correlations due to degeneracy and short-range interaction on the characteristics of the Thomson scattering signal. As such, the plasmon dispersion and damping width is calculated for a two-component plasma, where the electron subsystem is completely degenerate. Strong deviations of the plasmon resonance position due to the electron-electron correlations are observed at increasing Brueckner parameters r{sub s}. These results are of paramount importance for the interpretation of collective Thomson scattering spectra, as the determination of the free electron density from the plasmon resonance position requires a precise theory of the plasmon dispersion. Implications due to different approximations for the electron-electron correlation, i.e., different forms of the one-component local-field correction, are discussed.

  2. Thomson scattering diagnostics of SF6 gas-blasted arcs confined by a nozzle under free-recovery conditions

    NASA Astrophysics Data System (ADS)

    Tomita, Kentaro; Gojima, Daisuke; Shimizu, Takahiro; Uchino, Kiichiro; Nakano, Tomoyuki; Tanaka, Yasunori; Suzuki, Katsumi; Iijima, Takanori; Shinkai, Takeshi

    2015-07-01

    Collective Thomson scattering has been applied to gas-blasted arcs confined by a nozzle to measure their decay processes with respect to electron density (ne). Pure SF6 gas, an Ar/SF6 gas mixture (SF6 was 20, 40, 60, and 80% of the mixture), and pure Ar gas were used as arc-quenching media at atmospheric pressure. Copper-tungsten (40% copper) electrodes were installed inside a polytetrafluoroethylene (PTFE) nozzle and 50 mm-long gap arcs were generated between the electrodes. First, steady-state arcs were generated with 50 A current. Then, a semiconductor switch removed the arc current. It was found that after the current decreased to zero, ne exponentially decreased and the decay time constant of ne systematically decreased with an increasing SF6 gas ratio. Thomson scattering measured ne in the range 1021-1023 m-3. Self-emission measurements, which were performed with a high-speed camera at 200 000 frames per second, exhibited good agreement with the results of the Thomson scattering.

  3. Collective Thomson scattering measurements of the Ion Acoustic Decay Instability. Final report

    SciTech Connect

    Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.

    1993-12-31

    We have developed an uv collective Thomson scattering system for plasma produced by a short wavelength laser. The Ion Acoustic Decay Instabilities are studied in a large ({approximately}mm) scale, hot ({approximately}keV) plasma, which is relevant to a direct-driven laser fusion plasma. The IADI primary decay process is measured by the CTS. We used a random phase plate to minimize the non uniform irradiation of the interaction laser. Nevertheless, the threshold of the most unstable mode driven by the IADI is quite low. The measured threshold value agrees favorably with the theoretical value of the large scale plasma. We have also shown that the CTS from the IADI can be a good tool for measuring a local electron temperature. The measured results agree reasonably with the SAGE computer calculations. We used the real part of the wave (frequency) to estimate T{sub e}. The real part is, in general, reliable compared to the imaginary part such as the damping, and the growth rates. We have shown that the IADI can be easily excited in a large scale, hot plasma. The IADI has potentially important applications to direct drive laser fusion, and also critical surface diagnostic.

  4. Instrument to synchronize Thomson scattering diagnostic measurements with MHD acitivity in a tokamak

    SciTech Connect

    Wintenberg, A.L.

    1985-04-01

    An instrument to synchronize the firing of a ruby laser for a Thomson scattering diagnostic with plasma oscillations was designed, developed, and evaluated. The instrument will fire the laser at a user-selected phase of an input sine or sawtooth wave with an accuracy of +-15/sup 0/. Allowable frequencies range from 20 to 500 Hz for a sawtooth and from 1 to 30 kHz for a sine wave. The instrument also allows synchronization with a sine wave to be enabled by a preselected sawtooth phase. The instrument uses analog signal processing circuits to separate the signal components, remove unwanted components, and produce zero-phase synchronization pulses. The instrument measures the period between zero-phase pulses in order to produce phase synchronization pulses delayed a fraction of the period from the zero-phase pulses. The laser is fired by the phase synchronization pulse. Unwanted signal components are attenuated by bandpass filters. A digitally controlled self-adjusting bandpass filter for sine processing. The instrument was used to investigate the variation of the electron temperature profile with the phase of the x-ray signal from an Impurity Studies Experiment (ISX-B) plasma exhibiting magnetohydrodynamic (MHD) activity.

  5. Summary of Thomson-scattering data from the Tandem Mirror Experiment (TMX)

    SciTech Connect

    Goodman, R.K.

    1982-01-11

    We provide a synthesis of our Thomson-scattering measurements of electron temperature (T/sub e/) and density (n/sub e/) for the Tandem Mirror Experiment (TMX). TMX operated in two modes - high and low T/sub e/. When performing in the high T/sub e/ mode (in general > 100 eV), heating the central-cell ions with neutral beams raised T/sub e/ in the end plug. We achieved a maximum T/sub e/ of 260 eV in the east end plug. Specifically, our experiments demonstrated that in the end plug, the radial T/sub e/ profiles were flat to r = 5 cm; the ratio of potential (phi/sub p/) to T/sub e/ ranged between four and six. In addition, we found that although T/sub e/ in the central cell was generally comparable to that in the plug, it was often not constant along a magnetic field line. Under some conditions a non-Maxwellian electron distribution may have been present.

  6. X-ray Thomson scattering in warm dense matter at low frequencies

    SciTech Connect

    Murillo, Michael S.

    2010-03-15

    The low-frequency portion of the x-ray Thomson scattering spectrum is determined by electrons that follow the slow ion motion. This ion motion is characterized by the ion-ion dynamic structure factor, which contains a wealth of information about the ions, including structure and collective modes. The frequency-integrated (diffraction) contribution is considered first. An effective dressed-particle description of warm dense matter is derived from the quantum Ornstein-Zernike equations, and this is used to identify a Yukawa model for warm dense matter. The efficacy of this approach is validated by comparing a predicted structure with data from the extreme case of a liquid metal; good agreement is found. A Thomas-Fermi model is then introduced to allow the separation of bound and free states at finite temperatures, and issues with the definition of the ionization state in warm dense matter are discussed. For applications, analytic structure factors are given on either side of the Kirkwood line. Finally, several models are constructed for describing the slow dynamics of warm dense matter. Two classes of models are introduced that both satisfy the basic sum rules. One class of models is the 'plasmon-pole'-like class, which yields the dispersion of ion-acoustic waves. Damping is then included via generalized hydrodynamics models that incorporate viscous contributions.

  7. Improved Collective Thomson Scattering measurements of fast ions at ASDEX upgrade

    SciTech Connect

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Salewski, M.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Schubert, M.; Stober, J.; Tardini, G.; Wagner, D.; Collaboration: ASDEX Upgrade Team

    2014-08-21

    Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurement volume located close to the centre of the plasma. The measurements agree quantitatively with predictions of numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments.

  8. First operations with the new Collective Thomson Scattering diagnostic on the Frascati Tokamak Upgrade device

    NASA Astrophysics Data System (ADS)

    Bin, W.; Bruschi, A.; D'Arcangelo, O.; Castaldo, C.; De Angeli, M.; Figini, L.; Galperti, C.; Garavaglia, S.; Granucci, G.; Grosso, G.; Korsholm, S. B.; Lontano, M.; Mellera, V.; Minelli, D.; Moro, A.; Nardone, A.; Nielsen, S. K.; Rasmussen, J.; Simonetto, A.; Stejner, M.; Tartari, U.

    2015-10-01

    Anomalous emissions were found over the last few years in spectra of Collective Thomson Scattering (CTS) diagnostics in tokamak devices such as TEXTOR, ASDEX and FTU, in addition to real CTS signals. The signal frequency, down-shifted with respect to the probing one, suggested a possible origin in Parametric Decay Instability (PDI) processes correlated with the presence of magnetic islands and occurring for pumping wave power levels well below the threshold predicted by conventional models. A threshold below or close to the Electron Cyclotron Resonance Heating (ECRH) power levels could limit, under certain circumstances, the use of the ECRH in fusion devices. An accurate characterization of the conditions for the occurrence of this phenomenon and of its consequences is thus of primary importance. Exploiting the front-steering configuration available with the real-time launcher, the implementation of a new CTS setup now allows studying these anomalous emission phenomena in FTU under conditions of density and wave injection geometry that are more similar to those envisaged for CTS in ITER. The upgrades of the diagnostic are presented as well as a few preliminary spectra detected with the new system during the very first operations in 2014. The present work has been carried out under an EUROfusion Enabling Research project. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  9. Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experiment.

    PubMed

    Traverso, P J; Maurer, D A; Ennis, D A; Hartwell, G J; Goforth, M M; Loch, S D; Pearce, A J; Cianciosa, M R

    2014-11-01

    A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/#∼ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20-300 eV and densities of 5 × 10(18) to 5 × 10(19) m(-3) dependent upon operational scenario.

  10. Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experimenta)

    NASA Astrophysics Data System (ADS)

    Traverso, P. J.; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R.

    2014-11-01

    A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/{#} ˜ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20-300 eV and densities of 5 × 1018 to 5 × 1019 m-3 dependent upon operational scenario.

  11. Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experiment

    SciTech Connect

    Traverso, P. J. Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.; Goforth, M. M.; Loch, S. D.; Pearce, A. J.; Cianciosa, M. R.

    2014-11-15

    A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/#∼ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20–300 eV and densities of 5 × 10{sup 18} to 5 × 10{sup 19} m{sup −3} dependent upon operational scenario.

  12. Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Rasmussen, J.; Nielsen, S. K.; Stejner, M.; Galdon-Quiroga, J.; Garcia-Munoz, M.; Geiger, B.; Jacobsen, A. S.; Jaulmes, F.; Korsholm, S. B.; Lazanyi, N.; Leipold, F.; Ryter, F.; Salewski, M.; Schubert, M.; Stober, J.; Wagner, D.; the ASDEX Upgrade Team; the EUROFusion MST1 Team

    2016-11-01

    Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices. Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade. These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phase-space measurement volume of about 50% across sawtooth crashes, in good agreement with values predicted with the Kadomtsev sawtooth model implemented in TRANSP and with the sawtooth model in the EBdyna_go code. In contrast to the case of sawteeth, we observe no fast-ion redistribution in the presence of fishbone modes. We highlight how CTS measurements can discriminate between different sawtooth models, in particular when aided by multi-diagnostic velocity-space tomography, and briefly discuss our results in light of existing measurements from other fast-ion diagnostics.

  13. X-ray Thomson Scattering in Warm Dense Matter without the Chihara Decomposition

    NASA Astrophysics Data System (ADS)

    Baczewski, A. D.; Shulenburger, L.; Desjarlais, M. P.; Hansen, S. B.; Magyar, R. J.

    2016-03-01

    X-ray Thomson scattering is an important experimental technique used to measure the temperature, ionization state, structure, and density of warm dense matter (WDM). The fundamental property probed in these experiments is the electronic dynamic structure factor. In most models, this is decomposed into three terms [J. Chihara, J. Phys. F 17, 295 (1987)] representing the response of tightly bound, loosely bound, and free electrons. Accompanying this decomposition is the classification of electrons as either bound or free, which is useful for gapped and cold systems but becomes increasingly questionable as temperatures and pressures increase into the WDM regime. In this work we provide unambiguous first principles calculations of the dynamic structure factor of warm dense beryllium, independent of the Chihara form, by treating bound and free states under a single formalism. The computational approach is real-time finite-temperature time-dependent density functional theory (TDDFT) being applied here for the first time to WDM. We compare results from TDDFT to Chihara-based calculations for experimentally relevant conditions in shock-compressed beryllium.

  14. X-ray Thomson Scattering in Warm Dense Matter without the Chihara Decomposition.

    PubMed

    Baczewski, A D; Shulenburger, L; Desjarlais, M P; Hansen, S B; Magyar, R J

    2016-03-18

    X-ray Thomson scattering is an important experimental technique used to measure the temperature, ionization state, structure, and density of warm dense matter (WDM). The fundamental property probed in these experiments is the electronic dynamic structure factor. In most models, this is decomposed into three terms [J. Chihara, J. Phys. F 17, 295 (1987)] representing the response of tightly bound, loosely bound, and free electrons. Accompanying this decomposition is the classification of electrons as either bound or free, which is useful for gapped and cold systems but becomes increasingly questionable as temperatures and pressures increase into the WDM regime. In this work we provide unambiguous first principles calculations of the dynamic structure factor of warm dense beryllium, independent of the Chihara form, by treating bound and free states under a single formalism. The computational approach is real-time finite-temperature time-dependent density functional theory (TDDFT) being applied here for the first time to WDM. We compare results from TDDFT to Chihara-based calculations for experimentally relevant conditions in shock-compressed beryllium. PMID:27035307

  15. Enhanced Alignment Techniques for the Thomson Scattering Diagnostic on the Lithium Tokamak eXperiment (LTX)

    NASA Astrophysics Data System (ADS)

    Merino, Enrique; Kozub, Tom; Boyle, Dennis; Lucia, Matthew; Majeski, Richard; Kaita, Robert; Schmitt, John C.; Leblanc, Benoit; Diallo, Ahmed; Jacobson, C. M.

    2014-10-01

    The Thomson Scattering (TS) System in LTX is used to measure electron temperature and density profiles of core and edge plasmas. In view of TS measurements showing low signal-to-noise and high stray light, numerous improvements were performed in recent months. These will allow for better measurements. Due to the nature of LTX's lithium coated walls, a particular challenge was presented by alignment procedures which required insertion and precise positioning of equipment in the vacuum vessel without breaking vacuum. To overcome these difficulties, the laser flight tubes were removed and an alignment probe setup placed along the beam line on a differentially pumped assembly. The probe was then driven into the vacuum vessel and back-illumination of the viewing optics on it allowed for alignment and spatial calibration. Other upgrades included better bracing of flight tubes and viewing optics as well as a redesigned beam dump. An overview of these improvements will be presented. Supported by US DOE Contracts DE-AC02-09CH11466 and DE-AC52-07NA27344.

  16. Thomson scattering system on the TEXTOR tokamak using a multi-pass laser beam configuration

    NASA Astrophysics Data System (ADS)

    Kantor, M Yu; Donné, A J H; Jaspers, R; van der Meiden, H J; TEXTOR Team

    2009-05-01

    The main challenge for the Thomson scattering (TS) diagnostic on the TEXTOR tokamak is the detailed study of fast plasma events at a high spatial resolution and a high repetition rate of the measurements. The diagnostic uses intra-cavity probing of the plasma with a repetitively pulsed ruby laser and a fast CMOS camera as detectors. Since 2004, the TS system on TEXTOR has been gradually and systematically enhanced for the measurements of fast plasma events. For that it has recently been upgraded to obtain a multi-pass configuration. Two spherical mirrors have been installed that force the laser beam to probe the plasma a specified number of times before it is directed back into the laser medium. The diagnostics with the upgraded probing system have achieved the measurement accuracy of 3% for the electron temperature and 1.5% for the electron density at <1 cm spatial resolution and 3 × 1019 m-3 plasma density and can measure at 5 kHz during an interval up to 8 ms. This makes it possible to detect, amongst others, fine structures of magnetic islands and variations of the edge pedestal in the ELMy limiter H-mode.

  17. X-ray Thomson scattering of shocked carbon foam on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Ao, Tommy; Harding, Eric; Bailey, James; Lemke, Raymond; Desjarlais, Michael; Hansen, Stephanie; Smith, Ian; Reneker, Joseph; Romero, Dustin; Sinars, Daniel; Rochau, Gregory; Benage, John

    2015-06-01

    Experiments on the Sandia Z pulsed-power accelerator have demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, a space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foam was recorded on Z. The large electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cc, and temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data is comprised of three spatially distinct spectra that were simultaneously captured with a single spectrometer. These three spectra provide detailed information on the following target locations: the laser spot, the unshocked foam, and the shocked foam. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract DE-AC04-94AL85000.

  18. Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique

    SciTech Connect

    Yamamoto, N.; Tomita, K.; Sugita, K.; Kurita, T.; Nakashima, H.; Uchino, K.

    2012-07-15

    This paper reports on the development of a method for measuring xenon plasma properties using the laser Thomson scattering technique, for application to ion engine system design. The thresholds of photo-ionization of xenon plasma were investigated and the number density of metastable atoms, which are photo-ionized by a probe laser, was measured using laser absorption spectroscopy, for several conditions. The measured threshold energy of the probe laser using a plano-convex lens with a focal length of 200 mm was 150 mJ for a xenon mass flow rate of 20 {mu}g/s and incident microwave power of 6 W; the probe laser energy was therefore set as 80 mJ. Electron number density was found to be (6.2 {+-} 0.4) Multiplication-Sign 10{sup 17} m{sup -3} and electron temperature was found to be 2.2 {+-} 0.4 eV at a xenon mass flow rate of 20 {mu}g/s and incident microwave power of 6 W. The threshold of the probe laser intensity against photo-ionization in a miniature xenon ion thruster is almost constant for various mass flow rates, since the ratio of population of the metastable atoms to the electron number density is little changed.

  19. Frequency measurements of the gyrotrons used for collective Thomson scattering diagnostics at TEXTOR and ASDEX Upgrade

    SciTech Connect

    Woskov, P.; Bindslev, H.; Leipold, F.; Meo, F.; Nielsen, S. K.; Tsakadze, E. L.; Korsholm, S. B.; Scholten, J.; Tito, C.; Westerhof, E.; Oosterbeek, J. W.; Leuterer, F.; Monaco, F.; Muenich, M.; Wagner, D.

    2006-10-15

    High resolution frequency measurements of the 110 GHz gyrotron at TEXTOR and the 105 GHz mode of the two-frequency gyrotron (Odissey-1) at ASDEX Upgrade (AUG) have been made in support of fast ion collective Thomson scattering diagnostics. Measurements were done by harmonic heterodyne methods using both fast Fourier transform spectroscopy with digital oscilloscopes and fast scanning spectrum analyzers. Accurate frequencies were obtained with a frequency counter. At TEXTOR, at 180 kW forward power the starting frequency was 109.970{+-}0.005 GHz and chirped down as much as 27 MHz depending on the duty factor. At AUG, at 500 kW forward power the frequency started at 104.786 GHz and chirped down 104 MHz, with 90% of the chirp occurring in the first 100 ms. Plasma perturbation of the TEXTOR gyrotron was observed when both ion cyclotron resonance heating antennas and neutral beam injection were operating, producing modulation at 29 and 58 MHz in the gyrotron output. Each gyrotron was observed to have an instrumental measurement limited linewidth of 120 kHz full width at half maximum.

  20. A compact, low cost, 7 channel polychromator for Thomson scattering measurements

    SciTech Connect

    Carlstrom, T.N.; DeBoo, J.C.; Evanko, R.; Greenfield, C.M.; Hsieh, C.-L.; Snider, R.T.; Trost, P.

    1990-10-01

    A seven channel polychromator, utilizing high performance interference filters, has been tested for use in the multi-Nd:YAG laser Thomson scattering system for the DIII-D tokamak. Unique features of this polychromator are the combination of high throughput, easy alignment, flexibility, compact size, and low cost when compared with other alternatives. Light is introduced to the polychromator (f/1.75) via a fiber optic bundle which permits the use of small (3.0 cm dia) optics and leads to a compact design, an important design consideration for multiple polychromator systems. The light is cascaded through a series of different bandpass interference filters and relay lenses which are mounted on two precision parallel rails in such a way that alignment is trivial. The relay lenses are positioned directly in front of the filters so that light reflected from the filter passes through the lens twice. This leads to an efficient, compact design and reduces the angle of incidence (4{degree}) and the cone angle of light (4.5{degree}) seen by the filter, an important factor for narrowband (3.0 nm) filters. The transmission was optimized for 700--1100 nm by using broadband coatings throughout. The output images of each channel (2.3 mm dia) can be directly coupled to large format (3 nm dia) RCA silicon avalanche photodiode detectors, avoiding the losses caused by fiber optic coupling.

  1. Thomson scattering diagnostic system design for the Compact Toroidal Hybrid experiment.

    PubMed

    Traverso, P J; Maurer, D A; Ennis, D A; Hartwell, G J; Goforth, M M; Loch, S D; Pearce, A J; Cianciosa, M R

    2014-11-01

    A new Thomson scattering system using standard commercially available components has been designed for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH). The beam, generated by a frequency doubled Continuum PL DLS 2 J Nd:YAG laser, is passed vertically through an entrance Brewster window and an aperturing baffle system to minimize the stray laser light that could enter the collection optics. The beam line has been designed with an 8 m propagation distance to the mid-plane of the CTH device with the beam diameter kept less than 3 mm inside the plasma volume. The beam exits the vacuum system through another Brewster window and enters a beam dump, again to minimize the stray light in the vacuum chamber. Light collection, spectral processing, and signal detection are accomplished with an f/#∼ 1 aspheric lens, a commercially available Holospec f/1.8 spectrometer, and an Andor iStar DH740-18U-C3 image intensified camera. Spectral rejection of stray laser light, if needed, can be performed with the use of an optional interference filter at the spectrometer input. The system has been developed for initial single point measurements of plasmas with core electron temperatures of approximately 20-300 eV and densities of 5 × 10(18) to 5 × 10(19) m(-3) dependent upon operational scenario. PMID:25430265

  2. A study of core Thomson scattering measurements in ITER using a multi-laser approach

    NASA Astrophysics Data System (ADS)

    Kurskiev, G. S.; Sdvizhenskii, P. A.; Bassan, M.; Andrew, P.; Bazhenov, A. N.; Bukreev, I. M.; Chernakov, P. V.; Kochergin, M. M.; Kukushkin, A. B.; Kukushkin, A. S.; Mukhin, E. E.; Razdobarin, A. G.; Samsonov, D. S.; Semenov, V. V.; Tolstyakov, S. Yu.; Kajita, S.; Masyukevich, S. V.

    2015-05-01

    The electron component is the main channel for anomalous power loss and the main indicator of transient processes in the tokamak plasma. The electron temperature and density profiles mainly determine the operational mode of the machine. This imposes demanding requirements on the precision and on the spatial and temporal resolution of the Thomson scattering (TS) measurements. Measurements of such high electron temperature with good accuracy in a large fusion device such as ITER using TS encounter a number of physical problems. The 40 keV TS spectrum has a significant blue shift. Due to the transmission functions of the fibres and to their darkening that can occur under a strong neutron irradiation, the operational wavelength range is bounded on the blue side. For example, high temperature measurements become impossible with the 1064 nm probing wavelength since the TS signal within the boundaries of the operational window weakly depends on Te. The second problem is connected with the TS calibration. The TS system for a large fusion machine like ITER will have a set of optical components inaccessible for maintenance, and their spectral characteristics may change with time. Since the present concept of the TS system for ITER relies on the classical approach to measuring the shape of the scattered spectra using wide spectral channels, the diagnostic will be very sensitive to the changes in the optical transmission. The third complication is connected with the deviation of the electron velocity distribution function from a Maxwellian that can happen under a strong ECRH/ECCD, and it may additionally hamper the measurements. This paper analyses the advantages of a ‘multi-laser approach’ implementation for the current design of the core TS system. Such an approach assumes simultaneous plasma probing with different wavelengths that allows the measurement accuracy to be improved significantly and to perform the spectral calibration of the TS system. Comparative analysis

  3. Development of polarization-controlled multi-pass Thomson scattering system in the GAMMA 10 tandem mirror

    SciTech Connect

    Yoshikawa, M.; Morimoto, M.; Shima, Y.; Kohagura, J.; Sakamoto, M.; Nakashima, Y.; Imai, T.; Yasuhara, R.; Yamada, I.; Kawahata, K.; Funaba, H.; Minami, T.

    2012-10-15

    In the GAMMA 10 tandem mirror, the typical electron density is comparable to that of the peripheral plasma of torus-type fusion devices. Therefore, an effective method to increase Thomson scattering (TS) signals is required in order to improve signal quality. In GAMMA 10, the yttrium-aluminum-garnet (YAG)-TS system comprises a laser, incident optics, light collection optics, signal detection electronics, and a data recording system. We have been developing a multi-pass TS method for a polarization-based system based on the GAMMA 10 YAG TS. To evaluate the effectiveness of the polarization-based configuration, the multi-pass system was installed in the GAMMA 10 YAG-TS system, which is capable of double-pass scattering. We carried out a Rayleigh scattering experiment and applied this double-pass scattering system to the GAMMA 10 plasma. The integrated scattering signal was made about twice as large by the double-pass system.

  4. Three-dimensional time and frequency-domain theory of femtosecond x-ray pulse generation through Thomson Scattering

    SciTech Connect

    Brown, W J; Hartemann, F V

    2004-01-27

    The generation of high intensity, ultra-short x-ray pulses enables exciting new experimental capabilities, such as femtosecond pump-probe experiments used to temporally resolve material structural dynamics on atomic time scales. Thomson backscattering of a high intensity laser pulse with a bright relativistic electron bunch is a promising method for producing such high brightness x-ray pulses in the 10-100 keV range within a compact facility. While a variety of methods for producing sub-picosecond x-ray bursts by Thomson scattering exist, including compression of the electron bunch to sub-picosecond bunch lengths and/or colliding a sub-picosecond laser pulse in a side-on geometry to minimize the interaction time, a promising alternative approach to achieving this goal while maintaining ultra-high brightness is the production of a time correlated (or chirped) x-ray pulse in conjunction with pulse slicing or compression. We present the results of a complete analysis of this process using a recently developed 3-D time and frequency-domain code for analyzing the spatial, temporal, and spectral properties an x-ray beam produced by relativistic Thomson scattering. Based on the relativistic differential cross section, this code has the capability to calculate time and space dependent spectra of the x-ray photons produced from linear Thomson scattering for both bandwidth-limited and chirped incident laser pulses. Spectral broadening of the scattered x-ray pulse resulting from the incident laser bandwidth, laser focus, and the transverse and longitudinal phase space of the electron beam were examined. Simulations of chirped x-ray pulse production using both a chirped electron beam and a chirped laser pulse are presented. Required electron beam and laser parameters are summarized by investigating the effects of beam emittance, energy spread, and laser bandwidth on the scattered x-ray spectrum. It is shown that sufficient temporal correlation in the scattered x-ray spectrum

  5. Study of near scrape-off layer (SOL) temperature and density gradient lengths with Thomson scattering

    NASA Astrophysics Data System (ADS)

    Sun, H. J.; Wolfrum, E.; Eich, T.; Kurzan, B.; Potzel, S.; Stroth, U.; the ASDEX Upgrade Team

    2015-12-01

    Improvements to the Thomson scattering diagnostic have enabled the study of near scrape-off layer (SOL) decay lengths in the 2014 ASDEX Upgrade experimental campaign. A database of H-mode discharges has been studied using a two-line fit method for the core and log-linear fit for the near SOL region under both attached and detached divertor conditions. SOL electron temperature {{T}e} profiles have been found to have a radial exponential decay distribution which does not vary poloidally, consistent with the two-point model. In attached H-mode regimes, a log-linear regression shows that the SOL upstream dataset has the same main parametric dependencies as the scaling inferred from downstream Infrared camera measurements. A simple collisional relation from two-point model is found to best relate the upstream decay lengths and downstream divertor power widths. The SOL {{T}e} gradient length appears to be independent of {{T}e} pedestal parameters, but may correlate with the pedestal electron pressure parameters. Both the pedestal and SOL density and temperature scale lengths are linearly correlated with an almost constant gradient ratio, {ηe} . The smaller gradient ratio {ηe} and the fact that the Spitzer-Härm model is more valid, agrees with the studied plasma lying in the collisional regime. A transition to flat SOL ne profiles, previously reported for L-mode plasmas in many machines, has been observed in AUG detatched H-mode regimes. When the flattening of density profile happens in H-mode detached plasmas, the broadening of near SOL {{T}e} decay length {λ{{Te,u}}} also appears which may be good news for future machines.

  6. A Flexible Master Oscillator for a Thomson Scattering Pulse-Burst Laser System

    NASA Astrophysics Data System (ADS)

    den Hartog, D. J.; Young, W. C.

    2015-11-01

    A new master oscillator will be installed in the pulse-burst laser system used for high-rep-rate Thomson scattering on the MST experiment. This new master oscillator will enable pulse repetition rates up to 1 MHz, with the ability to program a burst of pulses with arbitrary and varying time separation between each pulse. In addition, the energy of each master oscillator pulse can be adjusted to compensate for gain variations in the power amplifier section of the laser system. This flexibility is accomplished by chopping a CW laser source with a high-bandwidth acousto-optic modulator (AOM). The laser source is a 1064 nm diode-pumped solid-state laser with continuous output power variable from 100 to 500 mW. The 2 mm diameter polarized beam is focused into the gallium phosphide crystal of the AOM, which deflects the beam by approximately 60 mrad. Beam deflection is controlled by a simple digital input pulse, and is capable of producing laser pulses of less than 20 ns width at repetition rates much greater than 1 MHz. These pulses from the output of the AOM will be collimated and propagated into the laser amplifier system, where they will be amplified to ~ 2 J/pulse and injected into the MST plasma. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences under Award Number DE-FC02-05ER54814, and by the National Science Foundation under Award Number PHY-0821899.

  7. Direct-View Multi-Point Two-Component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Gaffney, Richard L., Jr.; Cutler, Andrew D.

    2008-01-01

    This paper describes an instantaneous velocity measurement system based on the Doppler shift of elastically scattered laser light from gas molecules (Rayleigh scattering) relative to an incident laser. The system uses a pulsed laser as the light source, direct-viewing optics to collect the scattered light, an interferometer to analyze spectrally the scattered light mixed with the incident laser light, and a CCD camera to capture the resulting interferogram. The system is capable of simultaneous, spatially (approximately 0.2 mm(exp 3)) and temporally (approximately 40 ns) resolved, multiple point measurements of two orthogonal components of flow velocity in the presence of background scattered light, acoustic noise and vibrations, and flow particulates. Measurements in a large-scale axi-symmetric Mach 1.6 H2-air combustion-heated jet running at a flow sensible enthalpy specific to Mach 5.5 hypersonic flight are performed to demonstrate the technique. The measurements are compared with CFD calculations using a finite-volume discretization of the Favre-averaged Navier-Stokes equations (VULCAN code).

  8. Spatially resolved Thomson scattering measurements of the transition from the collective to the non-collective regime in a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Schaeffer, D. B.; Constantin, C. G.; Bondarenko, A. S.; Everson, E. T.; Niemann, C.

    2016-11-01

    We present optical Thomson scattering results that image for the first time in a single measurement the spatial transition from collective to non-collective scattering. Data were taken in the Phoenix laser laboratory at the University of California, Los Angeles. The Raptor laser was used to ablate a carbon plasma, which was diagnosed with the frequency-doubled Phoenix laser serving as a Thomson scattering probe. Scattered light was collected from the laser plasma up to 10 cm from the target surface and up to 10 us after ablation, and imaged with high spatial and spectral resolutions. The results show a strong Thomson collective feature close to the target surface that smoothly transitions to a non-collective feature over several mm.

  9. Ultra-fast x-ray Thomson scattering measurements of coalescing shock-heated matter

    SciTech Connect

    Kritcher, A; Neumayer, P; Castor, J; Doppner, T; Falcone, R W; Landen, O L; Lee, H J; Lee, R W; Morse, E C; Ng, A; Pollaine, S; Price, D; Glenzer, S H

    2008-05-29

    The experiment in this work was preformed at the Titan laser facility (S1) where a short pulse beam at a wavelength of 1053nm delivered up to 350J in 0.5 to 20 ps and a long pulse beam at 527nm, 2{omega} frequency provided energies up to 450J in 1 to 6 ns. Long pulse shaping in this experiment, similar to future capabilities at NIF, was primarily a 4ns long foot with an intensity of 1 x 10{sup 13} W/cm{sup 2}, followed by a 2ns long peak with an intensity of 3 x 10{sup 13} W/cm{sup 2}. A {approx} 600 um phase plate was used on the long pulse beam to moderate non-uniformities in the intensity profile. An illustration of the Thomson scattering setup for this experiment is provided in Fig. 1 of the main text. A nearly mono-energetic scattering source of {Delta}E/E {approx} 0.3% in the 4.5 keV Ti K-alpha line was produced via intense short-pulse laser irradiation of 1.9 x 3 x 0.01 mm Ti foils, creating energetic keV electrons in the process (S2, S3). The nearly isotropic source emission (S4) is produced in the cold solid density bulk of the foil from electron K shell ionization of neutral or weakly ionized atoms, with an emission size on the order of the laser focal spot. By optimizing the laser intensity and pulse width to 4.4 x 10{sup 16} W cm{sup -2}, a total of 2.3 x 10{sup 13} x-ray photons have been produced into 4{pi}. This value corresponds to a conversion efficiency of laser energy into Ti K-alpha x-ray energy of 5 x 10{sup -5}, see Fig. S1. These sources provide {approx}10 ps x-ray pulses as measured experimentally (S5).

  10. Benchmark and combined velocity-space tomography of fast-ion D-alpha spectroscopy and collective Thomson scattering measurements

    NASA Astrophysics Data System (ADS)

    Jacobsen, A. S.; Salewski, M.; Geiger, B.; Korsholm, S. B.; Leipold, F.; Nielsen, S. K.; Rasmussen, J.; Stejner, M.; Weiland, M.; the ASDEX Upgrade Team

    2016-04-01

    We demonstrate the combination of fast-ion D-alpha spectroscopy (FIDA) and collective Thomson scattering (CTS) measurements to determine a common best estimate of the fast-ion velocity distribution function by velocity-space tomography. We further demonstrate a benchmark of FIDA tomography and CTS measurements without using a numerical simulation as common reference. Combined velocity-space tomographies from FIDA and CTS measurements confirm that sawtooth crashes reduce the fast-ion phase-space densities in the plasma center and affect ions with pitches close to one more strongly than those with pitches close to zero.

  11. High-resolution Thomson scattering system on the COMPASS tokamak: Evaluation of plasma parameters and error analysis

    SciTech Connect

    Aftanas, M.; Bohm, P.; Bilkova, P.; Weinzettl, V.; Zajac, J.; Zacek, F.; Stockel, J.; Hron, M.; Panek, R.; Scannell, R.; Walsh, M. J.

    2012-10-15

    The electron density and temperature profiles measured by the Thomson scattering diagnostic on the COMPASS tokamak are used for estimation of electron kinetic energy, energy confinement time, and effective charge number Z{sub eff}. Data are compared with the line-integrated electron density measured by a microwave interferometer in an ohmically heated plasma with a circular cross section. An error analysis of both electron temperature and density are performed by two methods-a constant chi-square boundaries method and a Monte Carlo simulation, determining asymmetrical error bars for the electron temperature.

  12. Evolution of the millimeter-wave collective Thomson scattering system of the high-field tokamak Frascati Tokamak Upgrade

    SciTech Connect

    Tartari, U.; Grosso, G.; Granucci, G.; Gandini, F.; Garavaglia, S.; Grossetti, G.; Simonetto, A.; Mellera, V.; Muzzini, V.; Lubyako, L.; Shalashov, A.; Orsitto, F. P.; Ciccone, G.; Volpe, F.

    2007-04-15

    We first describe the improved receiving system of the diagnostic experiment of millimeter-wave collective Thomson scattering being run on the Frascati Tokamak Upgrade (FTU), and then discuss some peculiar problems and new operating procedures related to the investigation of strong anomalous spectra of nonthermal origin, many-orders-of-magnitude stronger than the ion thermal feature merged in them, systematically observed in the experimentation, and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a more general valence of the solutions actuated for the specific case of FTU are finally given.

  13. Evolution of the millimeter-wave collective Thomson scattering system of the high-field tokamak Frascati Tokamak Upgrade.

    PubMed

    Tartari, U; Grosso, G; Granucci, G; Gandini, F; Garavaglia, S; Grossetti, G; Simonetto, A; Mellera, V; Muzzini, V; Lubyako, L; Shalashov, A; Orsitto, F P; Ciccone, G; Volpe, F

    2007-04-01

    We first describe the improved receiving system of the diagnostic experiment of millimeter-wave collective Thomson scattering being run on the Frascati Tokamak Upgrade (FTU), and then discuss some peculiar problems and new operating procedures related to the investigation of strong anomalous spectra of nonthermal origin, many-orders-of-magnitude stronger than the ion thermal feature merged in them, systematically observed in the experimentation, and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a more general valence of the solutions actuated for the specific case of FTU are finally given. PMID:17477659

  14. Development of a high-resolution Thomson scattering system for plasma interactions with molten salt (FLiNaK)

    NASA Astrophysics Data System (ADS)

    Lee, K. Y.

    2014-10-01

    A high-resolution Thomson scattering system is presently being developed to measure the electron temperature and density profile during plasma interaction with molten salt. The system uses a 20-Hz Nd:YAG laser operating at the second harmonic (532 nm). The collection lens, having a 1:10 magnification ratio, measures 63 points along the 10-cm profile. The scattered light is transmitted by using an optical-fiber bundle, and is analyzed with a triple-grating spectrometer to further reduce stray light. Its spectral resolution is expected to be 0.03 nm. An intensified charge-coupled device (ICCD) camera consisting of a gated image intensifier coupled to the CCD camera is used to record the spectral distribution of the scattered light. An additional feature of operating the ICCD camera at 40-Hz to record the background signal is incorporated.

  15. Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

    2008-01-01

    This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

  16. Measurements of electron density and temperature in a miniature microwave discharge ion thruster using laser Thomson scattering technique

    NASA Astrophysics Data System (ADS)

    Yamamoto, N.; Tomita, K.; Yamasaki, N.; Tsuru, T.; Ezaki, T.; Kotani, Y.; Uchino, K.; Nakashima, H.

    2010-08-01

    In order to improve the thrust performance of a miniature microwave discharge ion thruster, the relationship between electron number density/temperature and operational conditions, mass flow rate, incident microwave power and magnetic field strength were measured by means of laser Thomson scattering. A photon counting method and a triple grating spectrometer were used against a small Thomson scattering signal and a strong stray laser light. Electron number density increased with incident microwave power and was saturated at critical incident microwave power; it was about 1.2 × 1018 m-3 at incident microwave power >8 W. In addition, electron number density increased with mass flow rate and became saturated; it was about 1.7 × 1018 m-3 at mass flow rate > 0.04 mg s-1. The electron number density gradually increased with an increase in the number of magnets, i.e. magnetic field strength. There was a sudden jump at thirteen magnets, although the thruster failed to ignite at fourteen magnets. This is because there is an optimum distance between the antenna and the electron cyclotron resonance layer. These results suggest that future improvement in thrust efficiency in miniature microwave discharge ion thrusters may come from the fine adjustment of the magnetic field configuration inside the discharge chamber.

  17. Sawtooth-cycle variation of electron temperature in MST, and prospects for improvement of fast Thomson scattering measurements

    NASA Astrophysics Data System (ADS)

    den Hartog, D. J.

    2005-10-01

    Initial measurements with the new Thomson scattering diagnostic on MST show a flattening of the Te profile during a sawtooth crash. These measurements were made in standard sawtoothing reversed-field pinch discharges, and show the core temperature dropping from 400 to approximately 150 eV, while the edge rises several-fold. Measurement of Te time dynamics in MST will be advanced by further development of the Thomson scattering diagnostic. In the near term, two independently triggerable lasers will be used to make two Te profile measurements separated by greater than or equal to 100 ns. By varying this separation time over the course of a data ensemble, an initial Te fluctuation spectrum will be produced. In the longer term, a third ``pulse-burst'' laser will be added to the diagnostic system. This laser will produce a burst of 10-30 approximately 1 J Q-switched pulses at repetition frequencies 5-250 kHz. The planned laser system will operate at 1064 nm and is based on existing Nd:YAG systems used to study fluid dynamics [Brian Thurow et al., Appl. Opt. 43, 5064 (2004)]. The burst train of laser pulses will enable the study of Te and ne dynamics in a single MST shot, and with ensembling, will enable correlation of Te and ne fluctuations with other fluctuating quantities.

  18. Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators.

    PubMed

    Luo, W; Yu, T P; Chen, M; Song, Y M; Zhu, Z C; Ma, Y Y; Zhuo, H B

    2014-12-29

    Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 1020 photons/s/mm2/mrad2/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.

  19. Development of a Thomson scattering system and its use in a rotating magnetic field driven field-reversed configurations plasma

    NASA Astrophysics Data System (ADS)

    Lee, Kiyong

    The Thomson scattering system has been utilized on the Translation Confinement & Sustainment Upgrade (TCSU) experiment to measure the electron temperature and density. The system uses five polychromators from General Atomics attached with three pre-amplifier modules from Princeton Plasma Physics Laboratory to measure five spatial points during a single plasma discharge. The diagnostic consisting of various mechanical and optical components is introduced, followed by the calibration procedure of the system. For validating measurements, the electron temperature and the relative density obtained from Thomson scattering are compared with measurements from the Langmuir probe. Both measurements are in good agreement. A power scan was conducted by applying different voltages to the rotating magnetic field (RMF) current drive to observe the scaling properties of temperature and density for even-parity and odd-parity RMF operations. Also, a discrepancy is observed when comparing the density based on pressure-balance with localized measurements. Further analysis indicates a possibility of an ion-temperature-gradient, presumably due to ion cyclotron heating, present during steady-state operation.

  20. 10 kHz repetitive high-resolution TV Thomson scattering on TEXTOR: Design and performance (invited)

    NASA Astrophysics Data System (ADS)

    van der Meiden, H. J.; Varshney, S. K.; Barth, C. J.; Oyevaar, T.; Jaspers, R.; Donné, A. J. H.; Kantor, M. Yu.; Kouprienko, D. V.; Uzgel, E.; Biel, W.; Pospieszczyk, A.; Textor Team

    2006-10-01

    In late 2003 a 10kHz multiposition Thomson scattering diagnostic with high spatial resolution became operational on the TEXTOR tokamak. In the initial phase of operation, one burst of 18 pulses of 12J each with a repetition rate of 5kHz could be extracted from the laser system. The installation of a low-dope ruby rod (spring 2005) resulted in a system, which can deliver higher pulse energy and moreover a divergence of better than 0.7mrad, leading to a big improvement in the detection of Thomson scattering photons. Furthermore, the number of laser pulses in one burst could be extended to even more than 30. The achieved laser energy of more than 15J/pulse makes it possible to measure electron temperature and density profiles with an observational error of 8% on the electron temperature (Te) and 4% on the electron density (ne) at ne=2.5×1019m-3, per spatial element of 7.5mm. The viewing optics enables sampling of either the full plasma diameter of 900mm with 120 spatial channels of 7.5mm each or a 160mm long edge chord with 98 spatial channels of 1.7mm each. The system, which has recently become available for physics exploration, has already been used to study the structure of m =2 magnetic islands and the response of the plasma to off-axis electron cyclotron resonance heating.

  1. Quantifying noise sources in the KSTAR 2014 Thomson Scattering system from the measured variation on electron temperature

    NASA Astrophysics Data System (ADS)

    Oh, T.-S.; Kim, K. H.; Lee, J. H.; Lee, S. H.; Scannell, R.; Field, A. R.; Cho, K.; Bawa'aneh, M. S.; Ghim, Y.-c.

    2016-03-01

    With the Thomson scattering (TS) system in KSTAR, temporal evolution of electron temperature (Te) is estimated using a weighted look-up table method with fast sampling (1.25 or 2.5 GS/s) digitizers during the 2014 KSTAR campaign. Background noise level is used as a weighting parameter without considering the photon noise due to the absence of information on absolute photon counts detected by the TS system. Estimated electron temperature during a relatively quiescent discharge are scattered, i.e., 15% variation on Te with respect to its mean value. We find that this 15% variation on Te cannot be explained solely by the background noise level which leads us to include photon noise effects in our analysis. Using synthetic data, we have estimated the required photon noise level consistent with the observation and determined the dominant noise source in KSTAR TS system.

  2. Qualification of a high-efficiency, gated spectrometer for x-ray Thomson scattering on the National Ignition Facility

    SciTech Connect

    Döppner, T.; Kritcher, A. L.; Bachmann, B.; Burns, S.; Hawreliak, J.; House, A.; Landen, O. L.; LePape, S.; Ma, T.; Pak, A.; Swift, D.; Neumayer, P.; Kraus, D.; Falcone, R. W.; Glenzer, S. H.

    2014-11-15

    We have designed, built, and successfully fielded a highly efficient and gated Bragg crystal spectrometer for x-ray Thomson scattering measurements on the National Ignition Facility (NIF). It utilizes a cylindrically curved Highly Oriented Pyrolytic Graphite crystal. Its spectral range of 7.4–10 keV is optimized for scattering experiments using a Zn He-α x-ray probe at 9.0 keV or Mo K-shell line emission around 18 keV in second diffraction order. The spectrometer has been designed as a diagnostic instrument manipulator-based instrument for the NIF target chamber at the Lawrence Livermore National Laboratory, USA. Here, we report on details of the spectrometer snout, its novel debris shield configuration and an in situ spectral calibration experiment with a Brass foil target, which demonstrated a spectral resolution of E/ΔE = 220 at 9.8 keV.

  3. Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

    NASA Astrophysics Data System (ADS)

    Jacobson, C. M.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A.

    2016-11-01

    The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

  4. Simulation of dark current and dark current-induced background photons in the Thomson scattering X-ray source

    NASA Astrophysics Data System (ADS)

    Zheng, Lianmin; Du, Yingchao; Huang, Wenhui; Tang, Chuanxiang

    2015-11-01

    A model of dark current generation in the photocathode radio-frequency (RF) gun is established in the Thomson scattering X-ray source, and dark current transport and losses along the beamline are simulated. A velocity bunching cavity is added between the RF gun and the first linac to achieve the longitudinal compression of the photoelectron bunches. Given the longitudinal acceleration and the transverse focusing of the bunching cavity, the dark current electrons with bunching are approximately three times more than those without bunching, and this condition aggravates the harm to the operation of the photoinjector. Numerous dark current electrons around the electron-laser interaction section hit against the pipe inner wall and two laser focusing mirrors, producing a large number of background photons. A simulation of the bremsstrahlung process using an MCNP code is presented, showing that the background photon yield is less than 2.1% of the scattering photon yield, which is acceptable for our application.

  5. Simulating x-ray Thomson scattering signals from high-density, millimetre-scale plasmas at the National Ignition Facility

    SciTech Connect

    Chapman, D. A.; Kraus, D.; Falcone, R. W.; Kritcher, A. L.; Bachmann, B.; Collins, G. W.; Gaffney, J. A.; Hawreliak, J. A.; Landen, O. L.; Le Pape, S.; Ma, T.; Nilsen, J.; Pak, A.; Swift, D. C.; Döppner, T.; Gericke, D. O.; Glenzer, S. H.; Guymer, T. M.; Neumayer, P.; Redmer, R.; and others

    2014-08-15

    We have developed a model for analysing x-ray Thomson scattering data from high-density, millimetre-scale inhomogeneous plasmas created during ultra-high pressure implosions at the National Ignition Facility in a spherically convergent geometry. The density weighting of the scattered signal and attenuation of the incident and scattered x-rays throughout the target are included using radial profiles of the density, opacity, ionization state, and temperature provided by radiation-hydrodynamics simulations. These simulations show that the scattered signal is strongly weighted toward the bulk of the shocked plasma and the Fermi degenerate material near the ablation front. We show that the scattered signal provides a good representation of the temperature of this highly nonuniform bulk plasma and can be determined to an accuracy of ca. 15% using typical data analysis techniques with simple 0D calculations. On the other hand, the mean ionization of the carbon in the bulk is underestimated. We suggest that this discrepancy is due to the convolution of scattering profiles from different regions of the target. Subsequently, we discuss modifications to the current platform to minimise the impact of inhomogeneities, as well as opacity, and also to enable probing of conditions more strongly weighted toward the compressed core.

  6. Picosecond Pulse Recirculation for High Average Brightness Thomson Scattering-based Gamma-ray Sources

    SciTech Connect

    Semenov, V. A.

    2009-06-12

    Pulse recirculation has been successfully demonstrated with the interaction laser system of LLNL's Thomson-Radiated Extreme X-ray (T-REX) source. The recirculation increased twenty-eight times the intensity of the light coming out of the laser system, demonstrating the capability of increasing the gamma-ray flux emitted by T-REX. The technical approach demonstrated could conceivably increase the average gamma-ray flux output by up to a hundred times.

  7. A theoretical study on phase-contrast mammography with Thomson-scattering x-ray sources

    SciTech Connect

    De Caro, Liberato; Giannini, Cinzia; Bellotti, Roberto; Tangaro, Sabina

    2009-10-15

    Purpose: The x-ray transmitted beam from any material/tissue depends on the complex refractive index (n=1-{delta}+i{beta}), where {delta} is responsible for the phase shift and {beta} is for the beam attenuation. Although for human tissues, the {delta} cross section is about 1000 times greater than the {beta} ones in the x-ray energy range from 10 to 150 keV, the gain in breast tumor visualization of phase-contrast mammography (PCM) with respect to absorption contact imaging (AI) is limited by the maximum dose that can be delivered to the patient. Moreover, in-line PC imaging (PCI) is the simplest experimental mode among all available x-ray PCI techniques since no optics are needed. The latter is a fundamental requirement in order to transfer the results of laboratory research into hospitals. Alternative to synchrotron radiation sources, the implementation of relativistic Thomson-scattering (TS) x-ray sources is particularly suitable for hospital use because of their high peak brightness within a relatively compact and affordable system. In this work, the possibility to realize PCM using a TS source in a hospital environment is studied, accounting for the effect of a finite deliverable dose on the PC visibility enhancement with respect to AI. Methods: The contrast-to-noise ratio of tumor-tissue lesions in PCM has been studied on the bases of a recent theoretical model, describing image contrast formation by means of both wave-optical theory and the mutual coherence formalism. The latter is used to describe the evolution, during wave propagation, of the coherence of the wave field emitted by a TS source. The contrast-to-noise ratio for both PCI and AI has been analyzed in terms of tumor size, beam energy, detector, and source distances, studying optimal conditions for performing PCM. Regarding other relevant factors which could influence ''tumor'' visibility, the authors have assumed simplified conditions such as a spherical shape description of the tumor inclusion

  8. Operation and beam profiling of an up to 200 kHz pulse-burst laser for Thomson scattering

    SciTech Connect

    Young, W. C. Den Hartog, D. J.

    2014-11-15

    A new, high-repetition rate laser is in development for use on the Thomson scattering diagnostic on the Madison Symmetric Torus. The laser has been tested at a rate of 200 kHz in a pulse-burst operation, producing bursts of 5 pulses above 1.5 J each, while capable of bursts of 17 pulses at 100 kHz. A master oscillator-power amplifier architecture is used with a Nd:YVO{sub 4} oscillator, four Nd:YAG amplifiers, and a Nd:glass amplifier. A radial profile over the pulse sequence is measured by using a set of graphite apertures and an energy meter, showing a change in beam quality over a pulsing sequence.

  9. First measurement of time evolution of electron temperature profiles with Nd:YAG Thomson scattering system on Heliotron J

    SciTech Connect

    Kenmochi, N. Tei, S.; Zang, L.; Ohtani, Y.; Kasajima, K.; Minami, T.; Takahashi, C.; Mizuuchi, T.; Kobayashi, S.; Nagasaki, K.; Nakamura, Y.; Okada, H.; Kado, S.; Yamamoto, S.; Ohshima, S.; Konoshima, S.; Shi, N.; Sano, F.

    2014-11-15

    A Nd:YAG Thomson scattering system has been developed for Heliotron J. The system consists of two 550 mJ 50 Hz lasers, large collection optics, and 25 radial channel (∼1 cm spatial resolution) interference polychromators. This measurement system achieves a S/N ratio of ∼50 for low-density plasma (n{sub e} ∼ 0.5 × 10{sup 19} m{sup −3}). A time evolution of electron temperature profiles was measured with this system for a high-intensity gas-puff (HIGP) fueling neutral-beam-injection plasma. The peripheral temperature of the higher-density phase after HIGP recovers to the low-density pre-HIGP level, suggesting that improving particle transport in the HIGP plasma may be possible.

  10. High-repetition CO{sub 2} laser for collective Thomson scattering diagnostic of {alpha} particles in burning plasmas

    SciTech Connect

    Kondoh, T.; Hayashi, T.; Kawano, Y.; Kusama, Y.; Sugie, T.; Miura, Y.; Koseki, R.; Kawahara, Y.

    2006-10-15

    A high-repetition and high-energy transversely excited atmospheric carbon dioxide (CO{sub 2}) laser for a collective Thomson scattering (CTS) diagnostic has been developed to establish a diagnostic method of confined {alpha} particles in burning plasmas. To excite a single-transverse and single-longitudinal mode, a continuous wave seed laser was injected to an unstable resonator with a cavity length of {approx}4.4 m. Pulse energy of 10 J with a repetition rate of 10 Hz has been achieved in the single-mode operation. Pulse energies of 18 J with a repetition rate of 10 Hz and 36 J with single shot operation have also been achieved in the multimode operation. These results give a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER), which requires single-mode energy of 20 J with repetition rate of 40 Hz.

  11. Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Döppner, T.; Kraus, D.; Neumayer, P.; Bachmann, B.; Emig, J.; Falcone, R. W.; Fletcher, L. B.; Hardy, M.; Kalantar, D. H.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Saunders, A. M.; Wood, R. D.

    2016-11-01

    We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.

  12. Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments

    SciTech Connect

    Harding, E. C.; Ao, T.; Bailey, J. E.; Loisel, G.; Sinars, D. B.; Geissel, M.; Rochau, G. A.; Smith, I. C.

    2015-04-15

    The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-rays with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.

  13. Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments.

    PubMed

    Harding, E C; Ao, T; Bailey, J E; Loisel, G; Sinars, D B; Geissel, M; Rochau, G A; Smith, I C

    2015-04-01

    The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-rays with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.

  14. Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Ao, T.; Bailey, J. E.; Loisel, G.; Sinars, D. B.; Geissel, M.; Rochau, G. A.; Smith, I. C.

    2015-04-01

    The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-rays with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.

  15. Operation and beam profiling of an up to 200 kHz pulse-burst laser for Thomson scattering

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Den Hartog, D. J.

    2014-11-01

    A new, high-repetition rate laser is in development for use on the Thomson scattering diagnostic on the Madison Symmetric Torus. The laser has been tested at a rate of 200 kHz in a pulse-burst operation, producing bursts of 5 pulses above 1.5 J each, while capable of bursts of 17 pulses at 100 kHz. A master oscillator-power amplifier architecture is used with a Nd:YVO4 oscillator, four Nd:YAG amplifiers, and a Nd:glass amplifier. A radial profile over the pulse sequence is measured by using a set of graphite apertures and an energy meter, showing a change in beam quality over a pulsing sequence.

  16. The use of ultraviolet Thomson scattering as a versatile diagnostic for detailed measurements of a collisional laser produced plasma

    SciTech Connect

    Tracy, M.D.

    1993-01-08

    Collective Thomson scattering from ion-acoustic waves at 266nm is used to obtain spatially resolved, two-dimensional electron density, sound speed, and radial drift profiles of a collisional laser plasma. An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where the electron densities approach n{sub c}/10. Laser plasmas of this type are important because they model some of the aspects of the plasmas found in high-gain laser-fusion pellets irradiated by long pulse widths where the laser light is absorbed mostly in the corona. The experimental results and LASNEX simulations agree within a percent standard deviation of 40% for the electron density and 50% for the sound speed and radial drift velocity. Thus it is shown that the hydrodynamics equations with classical coefficients and the numerical approximations in LASNEX are valid models of laser-heated, highly collisional plasmas. The versatility of Thomson scattering is expanded upon by extending existing theory with a Fokker-Planck based model to include plasmas that are characterized by (0 {le} k{sub ia}{lambda}{sub ii} {le} {infinity}) and ZT{sub e}/T{sub i}, where k{sub ia} is the ion- acoustic wave number, {lambda}{sub ii} is the ion-ion mean free path, Z is the ionization state of the plasma, and T{sub e}, T{sub i} are the electron and ion temperatures in electron volts respectively. The model is valid for plasmas in which the electrons are approximately collisionless, (k{sub ia}{lambda}{sub ei}, k{sub ia}{lambda}{sub ee} {ge} 1), and quasineutrality holds, ({alpha} {much_gt}1), where {alpha} = 1/k{lambda}{sub DE} and {lambda}{sub DE} is the electron Debye length. This newly developed model predicts the lineshape of the ion-acoustic Thomson spectra and when fit to experimental data provides a direct measurement of the relative thermal flow velocity between the electrons and ions.

  17. Design and Operation of a Frequency Doubled Nd:YAG Thomson Scattering System with Transmission Grating ICCD Spectrometer

    NASA Astrophysics Data System (ADS)

    Schoenbeck, N. L.; Dowd, A. S.; Fonck, R. J.; Schlossberg, D. J.; Winz, G. R.

    2012-10-01

    A novel Thomson scattering system has been deployed on the Pegasus Toroidal Experiment. It provides a relatively low-cost, simplified design. Scattering is achieved using a 7 ns, 2 J frequency doubled Nd:YAG laser operating at 532 nm. The laser focuses to ˜3 mm diameter within the plasma via a 7 m beam-line. The beam-line contains cameras as beam finders and remotely adjustable mirrors for shot-to-shot alignment. A custom multi-element lens collects scattered photons from 15 cm < Rmaj< 85 cm with 1.2 cm radial resolution. Eight fiber optic bundles provide 8 spatial points for sampling the laser or background light. Each set of 8 channels is measured in a single spectrometer that utilizes a high efficiency (˜80%) volume phase holographic grating and a high quantum efficiency (> 40%) image intensified CCD (ICCD) camera. Three spectrometers provide a total of 24 channels. Two interchangeable gratings exist to cover low (Te = 10--100 eV) and high (Te = 0.10--1 keV) electron temperature regimes on Pegasus. The spectrometer is optimized for ne from mid-10^18 to mid-10^19 m-3. The signal-to-noise expected is ˜0.5 of an equivalent system using Nd:YAG at 1064 nm and avalanche photodiode detectors.

  18. Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Ao, T.; Harding, E. C.; Bailey, J. E.; Lemke, R. W.; Desjarlais, M. P.; Hansen, S. B.; Smith, I. C.; Geissel, M.; Maurer, A.; Reneker, J.; Romero, D.; Sinars, D. B.; Rochau, G. A.; Benage, J. F.

    2016-03-01

    Experiments on the Sandia Z pulsed-power accelerator have demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (>20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm3, and temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data are composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Detailed spectral information from three target locations is provided simultaneously: the incident x-ray source, the scattered signal from unshocked foam, and the scattered signal from shocked foam.

  19. Uniform Laser-Driven Relativistic Electron Layer for Coherent Thomson Scattering

    SciTech Connect

    Wu, H.-C.; Fernandez, J.; Meyer-ter-Vehn, J.; Hegelich, B. M.

    2010-06-11

    A novel scheme is proposed to generate uniform relativistic electron layers for coherent Thomson backscattering. A few-cycle laser pulse is used to produce the electron layer from an ultrathin solid foil. The key element of the new scheme is an additional foil that reflects the drive-laser pulse, but lets the electrons pass almost unperturbed. Making use of two-dimensional particle-in-cell simulations and well-known basic theory, it is shown that the electrons, after interacting with both the drive and reflected laser pulses, form a very uniform flyer freely cruising with a high relativistic {gamma} factor exactly in the drive-laser direction (no transverse momentum). It backscatters the probe light with a full Doppler shift factor of 4{gamma}{sup 2}. The reflectivity and its decay due to layer expansion are discussed.

  20. Synchronized operation by field programmable gate array based signal controller for the Thomson scattering diagnostic system in KSTAR

    SciTech Connect

    Lee, W. R.; Park, M. K.; Lee, J. H.; Kim, H. S.; Kim, K. H.

    2012-09-15

    The Thomson scattering diagnostic system is successfully installed in the Korea Superconducting Tokamak Advanced Research (KSTAR) facility. We got the electron temperature and electron density data for the first time in 2011, 4th campaign using a field programmable gate array (FPGA) based signal control board. It operates as a signal generator, a detector, a controller, and a time measuring device. This board produces two configurable trigger pulses to operate Nd:YAG laser system and receives a laser beam detection signal from a photodiode detector. It allows a trigger pulse to be delivered to a time delay module to make a scattered signal measurement, measuring an asynchronous time value between the KSTAR timing board and the laser system injection signal. All functions are controlled by the embedded processor running on operating system within a single FPGA. It provides Ethernet communication interface and is configured with standard middleware to integrate with KSTAR. This controller has operated for two experimental campaigns including commissioning and performed the reconfiguration of logic designs to accommodate varying experimental situation without hardware rebuilding.

  1. Generation of uniform relativistic electron layer and linear and nonlinear coherent Thomson scattering

    NASA Astrophysics Data System (ADS)

    Wu, Hui-Chun; Meyer-Ter-Vehn, J.; Fernandez, J. C.; Hegelich, B. M.

    2010-11-01

    A novel, multi-layer target [H.-C. Wu et al., PRL 104, 234801 (2010)] is proposed to generate uniform relativistic electron layers for coherent Thomson backscattering (CTS). A few-cycle laser pulse produces an electron layer from an ultrathin foil and then a second foil reflects the laser pulse, but lets the electrons pass through unperturbed. 2D-PIC simulations show that after interacting with the drive and reflected laser pulses, the electrons form a very uniform flyer that propagates in the direction of laser propagation. Such a flyer backscatters light with a full Doppler shift factor of 4γ^2. Nonlinear CTS theory for relativistic laser intensity shows that compared with linear CTS, a relativistically intense laser induces transverse motion of the electron layer and decreases the linear Doppler shift by a factor 1+a0^2 . Consequently, in order to obtain the same x-ray photon energy as linear CTS, the nonlinear case needs higher electron energy. Theory also shows that CTS efficiency reaches saturation when laser amplitudea0>2. PIC simulations show that a powerful x-ray pulse (1 keV, 10 attoseconds, and GW power) can be generated and that diffraction-limited focusing may boost the intensity to of order 10^24W/cm^2.

  2. Correction of the spectral calibration of the Joint European Torus core light detecting and ranging Thomson scattering diagnostic using ray tracing

    SciTech Connect

    Hawke, J.; Scannell, R.; Maslov, M.; Migozzi, J. B.; Collaboration: JET-EFDA Contributors

    2013-10-15

    This work isolated the cause of the observed discrepancy between the electron temperature (T{sub e}) measurements before and after the JET Core LIDAR Thomson Scattering (TS) diagnostic was upgraded. In the upgrade process, stray light filters positioned just before the detectors were removed from the system. Modelling showed that the shift imposed on the stray light filters transmission functions due to the variations in the incidence angles of the collected photons impacted plasma measurements. To correct for this identified source of error, correction factors were developed using ray tracing models for the calibration and operational states of the diagnostic. The application of these correction factors resulted in an increase in the observed T{sub e}, resulting in the partial if not complete removal of the observed discrepancy in the measured T{sub e} between the JET core LIDAR TS diagnostic, High Resolution Thomson Scattering, and the Electron Cyclotron Emission diagnostics.

  3. Investigation of thermodynamic equilibrium in laser-induced aluminum plasma using the H{sub α} line profiles and Thomson scattering spectra

    SciTech Connect

    Cvejić, M. E-mail: krzysztof.dzierzega@uj.edu.pl; Dzierżęga, K. E-mail: krzysztof.dzierzega@uj.edu.pl; Pięta, T.

    2015-07-13

    We have studied isothermal equilibrium in the laser-induced plasma from aluminum pellets in argon at pressure of 200 mbar by using a method which combines the standard laser Thomson scattering and analysis of the H{sub α}, Stark-broadened, line profiles. Plasma was created using 4.5 ns, 4 mJ pulses from a Nd:YAG laser at 1064 nm. While electron density and temperature were determined from the electron feature of Thomson scattering spectra, the heavy particle temperature was obtained from the H{sub α} full profile applying computer simulation including ion-dynamical effects. We have found strong imbalance between these two temperatures during entire plasma evolution which indicates its non-isothermal character. At the same time, according to the McWhirter criterion, the electron density was high enough to establish plasma in local thermodynamic equilibrium.

  4. Correction of the spectral calibration of the Joint European Torus core light detecting and ranging Thomson scattering diagnostic using ray tracing.

    PubMed

    Hawke, J; Scannell, R; Maslov, M; Migozzi, J B

    2013-10-01

    This work isolated the cause of the observed discrepancy between the electron temperature (T(e)) measurements before and after the JET Core LIDAR Thomson Scattering (TS) diagnostic was upgraded. In the upgrade process, stray light filters positioned just before the detectors were removed from the system. Modelling showed that the shift imposed on the stray light filters transmission functions due to the variations in the incidence angles of the collected photons impacted plasma measurements. To correct for this identified source of error, correction factors were developed using ray tracing models for the calibration and operational states of the diagnostic. The application of these correction factors resulted in an increase in the observed T(e), resulting in the partial if not complete removal of the observed discrepancy in the measured T(e) between the JET core LIDAR TS diagnostic, High Resolution Thomson Scattering, and the Electron Cyclotron Emission diagnostics.

  5. Development of a new plasma diagnostic of the critical surface and studies of the ion acoustic decay instability using collective Thomson scattering. Final report

    SciTech Connect

    Mizuno, K.; DeGroot, J.S.; Seka, W.; Drake, R.P.

    1992-08-01

    We have developed 5-channel collective Thomson scattering system to measure the ion acoustic wave excited by the ion acoustic wave decay instabilities. The multichannel collective Thomson scattering technique was established with 4{omega} probe laser beam using GDL laser system at LLE, Univ. of Rochester. We have obtained the ionic charge state Z by measuring the second harmonic emission from the ion acoustic decay instability. The LASNEX computer simulation calculations have been carried out. The experimental results agree very well with the LASNEX computer simulation results with the flux number f=0.l. In high power laser regime, the spectrum become broad, and the {Delta}{gamma} decreases indicating that the turbulent like spectrum is observed. In order to understand the experimental results, we have developed a theory to study absorption of laser and heat transport. This new theory includes the temporal evolution of the heat conduction region. The results agree with flux-limited hydrodynamic simulations.

  6. Development of a new plasma diagnostic of the critical surface and studies of the ion acoustic decay instability using collective Thomson scattering

    SciTech Connect

    Mizuno, K.; DeGroot, J.S. ); Seka, W. . Lab. of Laser Energetics); Drake, R.P. )

    1992-01-01

    We have developed 5-channel collective Thomson scattering system to measure the ion acoustic wave excited by the ion acoustic wave decay instabilities. The multichannel collective Thomson scattering technique was established with 4{omega} probe laser beam using GDL laser system at LLE, Univ. of Rochester. We have obtained the ionic charge state Z by measuring the second harmonic emission from the ion acoustic decay instability. The LASNEX computer simulation calculations have been carried out. The experimental results agree very well with the LASNEX computer simulation results with the flux number f=0.l. In high power laser regime, the spectrum become broad, and the {Delta}{gamma} decreases indicating that the turbulent like spectrum is observed. In order to understand the experimental results, we have developed a theory to study absorption of laser and heat transport. This new theory includes the temporal evolution of the heat conduction region. The results agree with flux-limited hydrodynamic simulations.

  7. Theoretical Model and Interpretation of Dense Plasma X-Ray Thomson Scattering

    SciTech Connect

    Gregori, G; Landen, O; Hicks, D; Pasley, J; Collins, G; Celliers, P; Bastea, M; Glenzer, S

    2002-04-03

    The authors present analytical expressions for the dynamic structure factor, or form factor S(k,{omega}), which is the quantity describing the inelastic x-ray cross section from a dense plasma or a simple liquid. The results, based on the random phase approximation (RPA) for the treatment on the charged particle coupling, can be applied to describe scattering from either weakly coupled classical plasmas or degenerate electron liquids. The form factor correctly reproduces the Compton energy downshift and the usual Fermi-Dirac electron velocity distribution for S(k,{omega}) in the case of a cold degenerate plasma. the usual concept of scattering parameter is also reinterpreted for the degenerate case in order to include the effect of the Thomas-Fermi screening. The results shown in this work can be applied to interpreting x-ray scattering in warm dense plasmas occurring in inertial confinement fusion experiments or inside the interior of planets.

  8. Antenna decoupling requirements in a gyrotron collective Thomson scattering diagnostic (CTS) (abstract)

    SciTech Connect

    Orsitto, F.; Tartari, U.

    1995-01-01

    The required rejection ratio of the stray light in a CTS, respect to the launching power is investigated, for obtaining useful signal-to-noise ratio. This problem is faced considering the central gyrotron frequency {ital f}{sub 0}, as well as the in-band stray light raising from the spurious mode of the gyrotron and amplified cyclotron emission (the so-called gyrotron noise), falling into the scattered light spectrum. The statistical nature of the gyrotron noise in the scattering band is important because the required decoupling is obtained using the S/N formula where the fluctuation of the plasma radiation and the gyrotron noise fluctuation appears. It turns out that the total decoupling required at {ital f}{sub 0} is of the order of or greater than 80 dB, while in the scattering band could be less than 40 dB. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  9. Antenna decoupling requirements in a gyrotron collective Thomson scattering diagnostic (CTS)

    SciTech Connect

    Orsitto, F.; Tartari, U.

    1995-02-01

    The required rejection ratio of the stray light in a CTS, respect to the launching power is investigated, for obtaining useful signal-to-noise ratio. This problem is faced considering the central gyrotron frequency {ital f}{sub 0}, as well as the in-band stray light raising from the spurious mode of the gyrotron and amplified cyclotron emission (the so-called gyrotron noise), falling into the scattered light spectrum. The statistical nature of the gyrotron noise in the scattering band is important because the required decoupling is obtained using the S/N formula where the fluctuation of the plasma radiation and the gyrotron noise fluctuation appears. It turns out that the total decoupling required at {ital f}{sub 0} is of the order of or greater than 80 dB, while in the scattering band could be less than 40 dB. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  10. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Kubo, S.; Tanaka, K.; Seki, R.; Ogasawara, S.; Shimozuma, T.; Okada, K.; Kobayashi, S.; Mutoh, T.; Kawahata, K.; Watari, T.; LHD Experiment Group; Saito, T.; Tatematsu, Y.; Korsholm, S. B.; Salewski, M.

    2014-02-01

    A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclotron heating beam. To clarify the diagnostic applicability of the gyrotron in the 77 GHz frequency band, we investigated the dependence of the probe and receiver beam trajectories in plasmas with high electron densities of (4-5) × 1019 m-3 and low electron densities of (1-2) × 1019 m-3. At high density, a stray radiation component was observed in the CTS spectrum whereas it was negligibly small at low density. The CTS spectrum was measured and analysed after the in situ beam alignment using a beam scan. Qualitatively, the CTS spectrogram shows consistent response to ion temperatures of 1-2 keV for electron densities of (1-2) × 1019 m-3 and electron temperatures of 2-4 keV. The measured CTS spectrum shows an asymmetric shape at the foot of the bulk-ion region during the injection of 180 keV fast ions. This shape is explained by the fast-ion distribution in the velocity space (v‖, v⊥) based on Monte Carlo simulation results. The analysis method of the CTS spectra is used to evaluate the ion temperature and fast-ion velocity distribution from the measured CTS data.

  11. Measurement of Electron Temperature and Plasma Density via Thomson Scattering and Electric Probe in Low Temperature Plasmas

    NASA Astrophysics Data System (ADS)

    Woo, Hyun-Jong; Chung, Kyu-Sun; Lho, Taihyeop

    2011-10-01

    Laser Thomson scattering system has been developed for the measurements of electron temperature and plasma density in low temperature plasma by means of the Q-switched Nd:YAG laser with 2nd Harmonics (250 mJ at 532 nm, repetition rate of 20 Hz), triple grating spectrometer and ICCD camera. The triple grating spectrometer is composed of 3 grating (1800 gr/mm and 100 x 100 mm dimensions), 6 achromatic doublet lens (f=400 mm and 100 mm diameter) for reducing the abbreviation effect, two slits (entrance and exitance), opto- mechanical instruments, etc. The alignment and calibration of TGS system were performed by a diode laser and diffraction optics, Ne lamp (wavelength) and metal halide lamp (intensity), respectively. The LTS measurements were done wide ranges of 1

  12. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    NASA Astrophysics Data System (ADS)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  13. Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

    DOE PAGESBeta

    Ao, T.; Harding, E. C.; Bailey, J. E.; Lemke, R. W.; Desjarlais, M. P.; Hansen, S. B.; Smith, I. C.; Geissel, M.; Maurer, A.; Reneker, J.; et al

    2016-01-13

    Experiments on the Sandia Z pulsed-power accelerator demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (> 20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm3, and temperature ofmore » 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data is composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Furthermore, these spectra provide detailed information on three target locations: the laser spot, the unshocked foam, and the shocked foam.« less

  14. Customizable electron beams from optically controlled laser plasma acceleration for γ-ray sources based on inverse Thomson scattering

    NASA Astrophysics Data System (ADS)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2016-09-01

    Laser wakefield acceleration of electrons in the blowout regime can be controlled by tailoring the laser pulse phase and the plasma target. The 100 nm-scale bandwidth and negative frequency chirp of the optical driver compensate for the nonlinear frequency red-shift imparted by wakefield excitation. This mitigates pulse self-steepening and suppresses continuous injection. The plasma channel suppresses diffraction of the pulse leading edge, further reducing self-steepening, making injection even quieter. Besides, the channel destabilizes the pulse tail confined within the accelerator cavity (the electron density "bubble"), causing oscillations in the bubble size. The resulting periodic injection generates background-free comb-like beams - sequences of synchronized, low phase-space volume bunches. Controlling the number of bunches, their energy, and energy spacing by varying the channel radius and the pulse length (as permitted by the large bandwidth) enables the design of a tunable, all-optical source of polychromatic, pulsed γ-rays using the mechanism of inverse Thomson scattering. Such source may radiate ~107 quasi-monochromatic 10 MeV-scale photons per shot into a microsteradian-scale observation angle. The photon energy is distributed among several distinct bands, each having sub-25% energy spread dictated by the mrad-scale divergence of electron beam.

  15. Thomson-scattering measurements of electron temperature and density in a plasma channel created by a relativistic electron beam

    SciTech Connect

    Allen, G.R.; Parke Davis, H.; Brandenburg, J.E.

    1983-01-01

    The electron density (n/sub e/) and temperature (T/sub e/) of the plasma channel created by the propagation of a relativistic electron beam in air have been measured by a ruby laser Thomson scattering diagnostic. The measurements were made at the MIMI electron beam accelerator (1.6 MV, 21 kA, 70 ns) at various times during the plasma channel development, with 25 ns temporal resolution and 2 mm radial resolution. For example, in 5 Torr air, at the time of maximum electron beam current, the results are n/sub e/ = 1.86 x 10/sup 15/ cm/sup -3/ (+- 12%), T/sub e/ = 4.24 eV (+- 20%). These results, as well as those with other timing, are in good agreement with the theoretical results of the Air Propagation Code: n/sub e/ = 1.65 x 10/sup 15/ cm/sup -3/, T/sub e/ = 2.59 eV. Signal-to-noise is very good (10:1), limited by x-ray fluorescence of the fiber optics at the spectrometer. In fielding the diagnostic on higher energy accelerators, however, the dominant noise is expected to be the background light from the plasma and hot gas, or the fluorescence of the collecting optics. Improvements to the diagnostic and an ongoing experiment in 80 Torr of air, 4 MV, 50 kA to address these issues is presented.

  16. Observations of continuum depression in warm dense matter with x-ray Thomson scattering.

    PubMed

    Fletcher, L B; Kritcher, A L; Pak, A; Ma, T; Döppner, T; Fortmann, C; Divol, L; Jones, O S; Landen, O L; Scott, H A; Vorberger, J; Chapman, D A; Gericke, D O; Mattern, B A; Seidler, G T; Gregori, G; Falcone, R W; Glenzer, S H

    2014-04-11

    Detailed measurements of the electron densities, temperatures, and ionization states of compressed CH shells approaching pressures of 50 Mbar are achieved with spectrally resolved x-ray scattering. Laser-produced 9 keV x-rays probe the plasma during the transient state of three-shock coalescence. High signal-to-noise x-ray scattering spectra show direct evidence of continuum depression in highly degenerate warm dense matter states with electron densities ne>1024  cm-3. The measured densities and temperatures agree well with radiation-hydrodynamic modeling when accounting for continuum lowering in calculations that employ detailed configuration accounting.

  17. Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects

    NASA Astrophysics Data System (ADS)

    Tojo, H.; Yamada, I.; Yasuhara, R.; Ejiri, A.; Hiratsuka, J.; Togashi, H.; Yatsuka, E.; Hatae, T.; Funaba, H.; Hayashi, H.; Takase, Y.; Itami, K.

    2016-09-01

    This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (Te) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured Te and intensity of the signals. How accurate the values are depends on the electron temperature (Te) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high Te and a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the Te in a wide Te range spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the Te measurements are valid under harsh radiation conditions. This method to obtain Te can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

  18. Design and development of detector signal conditioning electronics for SST-1 Thomson scattering system.

    PubMed

    Thakar, Aruna; Kumar, Ajai; Thomas, Jinto; Chavda, Chhaya

    2008-09-01

    An IR enhanced thermoelectrically cooled Si-avalanche photodiode (Si-APD) module is used for detection of scattered photons from plasma electrons. Present design of signal conditioning electronics for the APD has fast (50 MHz) and slow (500 kHz) channels to measure scattered and plasma background light, respectively. We report design analysis for different stages and their performance. The performance of fast channel is analyzed for two different group delays, speed, linearity, and its cross-talk with slow channel. Temperature dependence of APD's responsivity is studied in the wavelength range of 900-1060 nm. A minimum detection of approximately 25 photoelectrons (with SN=1) in the range of 5 to 25 degrees C is achieved at an APD gain of 75 in the present design.

  19. Final Report LDRD 02-ERD-013 Dense Plasma Characterization by X-ray Thomson Scattering

    SciTech Connect

    Landen, O L; Glenzer, S H; Gregori, G; Pollaine, S M; Hammer, J H; Rogers, F; Meezan, N B; Chung, H; Lee, R W

    2005-02-11

    We have successfully demonstrated spectrally-resolved x-ray scattering in a variety of dense plasmas as a powerful new technique for providing microscopic dense plasma parameters unattainable by other means. The results have also been used to distinguish between ionization balance models. This has led to 10 published or to be published papers, 8 invited talks and significant interest from both internal and external experimental plasma physicists and the international statistical plasma physics theory community.

  20. COMPUTING THE CONTINUUM POLARIZATION FROM THOMSON SCATTERING IN GASEOUS CIRCUMSTELLAR DISKS

    SciTech Connect

    Halonen, R. J.; Mackay, F. E.; Jones, C. E.

    2013-01-15

    We investigate the computation of the intrinsic continuum linear polarization from electron scattering in optically thin and thick circumstellar disks of gas. We present the use of a non-LTE radiative transfer code, along with two different computational methods for obtaining the Stokes parameters, to reproduce the polarization levels that arise from disks of classical Be stars. Since the pioneering work of Poeckert and Marlborough, numerous improvements and refinements have been incorporated into computational radiative transfer models of classical Be stars. We present an assessment of the effect of several improvements on Poeckert and Marlborough's technique for calculating the polarization levels of the classical Be star {gamma} Cas. We find that improvements to the sampling of the disk density and the inclusion of a non-isothermal structure for the gas in the disk yield polarization levels that differ from the levels expected by Poeckert and Marlborough. Principally, the inclusion of the self-consistent calculation of the thermal structure of the disk has a significant impact on the resulting polarization. In addition, we assess the importance of the inclusion of multiple scattering calculations in predicting the continuum polarization in classical Be stars. We confirm that multiple scattering calculations are necessary for studying the linear polarization levels from optically thick gaseous disks around classical Be stars.

  1. T-REX: Thomson-Radiated Extreme X-rays Moving X-Ray Science into the ''Nuclear'' Applications Space with Thompson Scattered Photons

    SciTech Connect

    Barty, C P; Hartemann, F V

    2004-09-21

    The scattering of laser photons from relativistic electrons (Thomson scattering) has been demonstrated to be a viable method for the production of ultrashort-duration pulses of tunable radiation in the 10-keV to 100-keV range. Photons in this range are capable of exciting or ionizing even the most tightly bound of atomic electrons. A wide variety of atomistic scale applications are possible. For example, Thomson x-ray sources have been constructed at LLNL (PLEIADES) and LBL as picosecond, stroboscopic probes of atomic-scale dynamics and at Vanderbilt University as element-specific tools for medical radiography and radiology. While these sources have demonstrated an attractive ability to simultaneously probe on an atomic spatial and temporal scale, they do not necessarily exploit the full potential of the Thomson scattering process to produce high-brightness, high-energy photons. In this white paper, we suggest that the peak brightness of Thomson sources can scale as fast as the 4th power of electron beam energy and that production via Thomson scattering of quasi-monochromatic, tunable radiation in the ''nuclear-range'' between 100-keV and several MeV is potentially a much more attractive application space for this process. Traditional sources in this regime are inherently ultra-broadband and decline rapidly in brightness as a function of photon energy. The output from dedicated, national-laboratory-scale, synchrotron facilities, e.g. APS, SPring8, ESRF etc., declines by more than 10 orders from 100 keV to 1 MeV. At 1 MeV, we conservatively estimate that Thomson-source, peak brightness can exceed that of APS (the best machine in the DOE complex) by more than 15 orders of magnitude. In much the same way that tunable lasers revolutionized atomic spectroscopy, this ''Peta-step'' advance in tunable, narrow-bandwidth, capability should enable entirely new fields of study and new, programmatically-interesting, applications such as: micrometer-spatial-resolution, Me

  2. Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system

    SciTech Connect

    Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K.

    2013-09-15

    Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ∼0.3 mm and ∼0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30 keV) can be expected in the refraction system.

  3. Characterization of heat transport dynamics in laser-produced plasmas using collective Thomson scattering: Simulation and proposed experiment

    SciTech Connect

    Cameron, S.M.; Camacho, J.F.

    1995-12-01

    The authors propose an experiment in which the collective Thomson scattering lineshape obtained from ion acoustic waves is used to infer the spatial structure of local heat transport parameters and collisionality in a laser-produced plasma. The peak-height asymmetry in the ion acoustic wave spectrum will be used in conjunction with a recently developed model describing the effects of collisional and Landau damping contributions on the low-frequency electron density fluctuation spectrum to extract the relative electron drift velocity. This drift arises from temperature gradients in the plasma. The local heat flux, which is proportional to the drift, can then be estimated, and the electron thermal conductivity will be inferred from the relationship between the calculated heat flux and the experimentally determined temperature gradient. Damping of the entropy wave component at zero mode frequency is shown to be an estimate of the ion thermal conductivity, and its visibility is a direct measure of the ion-ion mean free path. The authors also propose to measure thermal transport parameters under dynamic conditions in which the plasma is heated impulsively by a laser beam on a fast ({approximately}50 ps) time scale. This technique will enable the authors to study heat transport in the presence of the large temperature gradients that are generated by this local heating mechanism. Deviations of the inferred local thermal conductivity from its Spitzer-Haerm value can be used to study the transition to the nonlocal heat transport regime. The authors have constructed a simple numerical model of this proposed experiment and present the results of a simulation. 41 refs., 9 figs.

  4. Design of collective Thomson scattering system using 77 GHz gyrotron for bulk and tail ion diagnostics in the large helical device

    SciTech Connect

    Nishiura, M.; Tanaka, K.; Kubo, S.; Kawahata, K.; Shimozuma, T.; Mutoh, T.; Saito, T.; Tatematsu, Y.; Notake, T.

    2008-10-15

    Collective Thomson scattering (CTS) system is expected to be a strong diagnostic tool for measuring thermal and fast ion distribution function at a local point inside plasmas. The electron cyclotron resonance heating system using a gyrotron at the frequency range of 77 GHz has been installed at the large helical device (LHD). The feasibility of CTS system using the 77 GHz gyrotron is assessed in terms of scattering spectrum and a background noise of the electron cyclotron emission, which affect the signal to noise ratio, with the realistic plasma parameters and incident port locations of LHD. Based on the calculated scattering spectra for bulk and tail fast ion diagnostics, the scattering radiation receiver system with gyrotron frequency feedback circuit is proposed to avoid the frequency chirping.

  5. Status of the LBL experiment on femtosecond x-ray generation through 90{degree} Thomson scattering

    SciTech Connect

    Leemans, W.; Chattopadhyay, S.; Conde, M.; Glover, E.; Kim, K.J.; Schoenlein, R.; Shank, C.V.

    1994-06-01

    A status report on the generation of femtosecond X-ray pulses through 90{degrees} Thompson scattering is presented. The experiment involves a relativistic electron beam (tunable from 25--50 MeV) with a bunch length of 10 ps containing 1 {minus}2 nC, and a ultrashort pulse (50--200 fs), high power (4 TW) 0.8 {mu}m Ti:Al{sub 2}O{sub 3} laser system. Both beams are focussed down to about a 50 {mu}m waist size and intersect at 90{degrees}. The laser field acts as an electromagnetic undulator for the relativistic electron beam generating radiation upshifted by 2 {gamma}{sup 2} and a pulse length given by the transit time of the laser beam across the electron beam. For a 50 MeV electron beam we expect 10{sup 5} photons at 0.4 {angstrom} (10% bandwidth) in a cone angle of 6 mrad in a 170 fs pulse.

  6. Single-shot Thomson scattering on argon plasmas created by the Microwave Plasma Torch; evidence for a new plasma class

    NASA Astrophysics Data System (ADS)

    van der Mullen, J. J. A. M.; van de Sande, M. J.; de Vries, N.; Broks, B.; Iordanova, E.; Gamero, A.; Torres, J.; Sola, A.

    2007-10-01

    To determine the fine-structure size of plasmas created by a Microwave Plasma Torch (MPT), single-shot Thomson scattering (TS) measurements were performed. The aim was to find a solution for the long-standing discrepancy between experiments and Global Plasma Models (GPMs). Since these GPMs are based on the assumption that (ambipolar) diffusion is the main loss process for charged particles, the diffusion length and thus the fine-structure size should be known with high precision before an appropriate theory-experiment comparison can be carried out. In order to avoid the effect of blurring, which is created during the accumulation of multi-shot TS signals and which obscures the fine-structures, single-shot measurements are indispensable to determine the diffusion length. The results of the present study reveal that the impression created by multi-shot TS that MPT plasmas resemble stable cones is not (always) correct; instead it is found that the plasmas we investigated are tiny filaments that rotate on the mantle of a virtual cone. However, the fine-structure, especially the thickness, of these filaments is not substantially smaller than that of the virtual cone. By applying the theory-experiment comparison to the filament we found that the disagreement is even worse than what we found for the cone. It is therefore inevitable to conclude that the main proposition of the GPM is incorrect. Apparently the plasma is not diffusive in nature; that is, the main loss process of charged particles is not provided by diffusion but by local chemistry. Swirling in a cool nitrogen-containing environment favors the production of molecular ions such as Ar 2+ and N 2+ inside the plasma filament. The destruction of these molecular ions leads to recombination frequencies that are more than a factor 100 larger than what ambipolar diffusion can provide. Thus we are dealing with another plasma class and it is useful to divide plasmas into diffusive and reactive plasmas. The well

  7. Polarimetric Variations of Binary Stars. I. Numerical Simulations for Circular and Eccentric Binaries in Thomson Scattering Envelopes

    NASA Astrophysics Data System (ADS)

    Manset, N.; Bastien, P.

    2000-07-01

    We present numerical simulations of the polarimetric variations produced by a binary star placed at the center of an empty spherical cavity inside a circumbinary ellipsoidal and optically thin envelope. Thomson single-scattering is considered along with pre- and postscattering extinction factors which produce a time-varying optical depth. The orbits are circular or eccentric. The mass ratio (and luminosity ratio) is in general equal to 1.0. As a function of the orbital (and envelope) inclination, the polarization follows a sin2(i) law. High polarization levels will result from a high inclination, a high optical depth, a flat envelope, or a big central cavity. Polarimetric variations are more apparent for a low inclination, a high optical depth, a flat envelope, a small cavity, or an orbit that brings the stars close to the inner edge of the cavity. It is then shown that the 1978 BME (Brown, McLean, & Emslie) model can be used to find the orbital inclination if it is >~45°, even though this model does not include variable absorption effects as in our simulations. The geometry (flatness of the envelope, size of the central cavity) and size of the orbit have no significant influence on the inclination found by the BME model. For eccentric orbits, single-periodic variations (variations seen once per orbit) appear for eccentricities as low as 0.10. As the eccentricity increases, these single-periodic variations dominate over the double-periodic (seen twice per orbit) ones. The inclinations found by the BME model with the first-order coefficients are then more reliable than those found with the second-order coefficients, especially for the highest eccentricities. For low eccentricities, e<~0.3, the inclinations can be found with the first or second-order coefficients, if i>20deg and i>45deg, respectively. For the high eccentricities, 0.310deg. Since with polarimetric observations the true inclination is not

  8. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited)

    NASA Astrophysics Data System (ADS)

    Swadling, G. F.; Lebedev, S. V.; Hall, G. N.; Patankar, S.; Stewart, N. H.; Smith, R. A.; Harvey-Thompson, A. J.; Burdiak, G. C.; de Grouchy, P.; Skidmore, J.; Suttle, L.; Suzuki-Vidal, F.; Bland, S. N.; Kwek, K. H.; Pickworth, L.; Bennett, M.; Hare, J. D.; Rozmus, W.; Yuan, J.

    2014-11-01

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7-14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  9. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited)

    SciTech Connect

    Swadling, G. F. Lebedev, S. V.; Hall, G. N.; Patankar, S.; Stewart, N. H.; Smith, R. A.; Burdiak, G. C.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Suzuki-Vidal, F.; Bland, S. N.; Kwek, K. H.; Pickworth, L.; Bennett, M.; Hare, J. D.; Harvey-Thompson, A. J.; Rozmus, W.; Yuan, J.

    2014-11-15

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7–14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  10. Diagnosing collisions of magnetized, high energy density plasma flows using a combination of collective Thomson scattering, Faraday rotation, and interferometry (invited).

    PubMed

    Swadling, G F; Lebedev, S V; Hall, G N; Patankar, S; Stewart, N H; Smith, R A; Harvey-Thompson, A J; Burdiak, G C; de Grouchy, P; Skidmore, J; Suttle, L; Suzuki-Vidal, F; Bland, S N; Kwek, K H; Pickworth, L; Bennett, M; Hare, J D; Rozmus, W; Yuan, J

    2014-11-01

    A suite of laser based diagnostics is used to study interactions of magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures the time-resolved local flow velocity and temperature across 7-14 spatial positions. The scattering spectrum is recorded from multiple directions, allowing more accurate reconstruction of the flow velocity vectors. The areal electron density is measured using 2D interferometry; optimisation and analysis are discussed. The Faraday rotation diagnostic, operating at 1053 nm, measures the magnetic field distribution in the plasma. Measurements obtained simultaneously by these diagnostics are used to constrain analysis, increasing the accuracy of interpretation.

  11. Continued Development of Python-Based Thomson Data Analysis and Associated Visualization Tool for NSTX-U

    NASA Astrophysics Data System (ADS)

    Wallace, William; Miller, Jared; Diallo, Ahmed

    2015-11-01

    MultiPoint Thomson Scattering (MPTS) is an established, accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Two Nd:YAG (1064 nm) lasers are fired into the plasma with a effective frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the NSTX-U midplane collect the scattered photons at various radii/scattering angles, and the avalanche photodiode voltages are saved to an MDSplus tree for later analysis. IDL code is then used to determine plasma temperature, pressure, and density from the captured polychromator measurements via Selden formulas. [1] Previous work [2] converted the single-processor IDL code into Python code, and prepared a new architecture for multiprocessing MPTS in parallel. However, that work was not completed to the generation of output data and curve fits that match with the previous IDL. This project refactored the Python code into a object-oriented architecture, and created a software test suite for the new architecture which allowed identification of the code which generated the difference in output. Another effort currently underway is to display the Thomson data in an intuitive, interactive format. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Community College Internship (CCI) program.

  12. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    NASA Astrophysics Data System (ADS)

    MacDonald, M. J.; Gorkhover, T.; Bachmann, B.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Ferguson, K. R.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Hau-Riege, S. P.; Kraus, D.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K.-H.; O'Grady, C. P.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Swiggers, M.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-11-01

    Atomic clusters can serve as ideal model systems for exploring ultrafast (˜100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

  13. Theoretical treatments of the bound-free contribution and experimental best practice in X-ray Thomson scattering from warm dense matter

    NASA Astrophysics Data System (ADS)

    Mattern, Brian A.; Seidler, Gerald T.

    2013-02-01

    By comparison with high-resolution synchrotron x-ray experimental results, we assess several theoretical treatments for the bound-free (core-electron) contribution to x-ray Thomson scattering (i.e., also known as nonresonant inelastic x-ray scattering). We identify an often overlooked source of systematic error in the plane-wave form factor approximation (PWFFA) used in the inference of temperature, ionization state, and free electron density in some laser-driven compression studies of warm dense matter. This error is due to a direct violation of energy conservation in the PWFFA. We propose an improved practice for the bound-free term that will be particularly relevant for XRTS experiments performed with somewhat improved energy resolution at the National Ignition Facility or the Linac Coherent Light Source. Our results raise important questions about the accuracy of state variable determination in XRTS studies, given that the limited information content in low-resolution XRTS spectra does not strongly constrain the models of electronic structure being used to fit the spectra.

  14. A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

    NASA Astrophysics Data System (ADS)

    Corvan, D. J.; Zepf, M.; Sarri, G.

    2016-09-01

    γ-Ray sources are among the most fundamental experimental tools currently available to modern physics. As well as the obvious benefits to fundamental research, an ultra-bright source of γ-rays could form the foundation of scanning of shipping containers for special nuclear materials and provide the bases for new types of cancer therapy. However, for these applications to prove viable, γ-ray sources must become compact and relatively cheap to manufacture. In recent years, advances in laser technology have formed the cornerstone of optical sources of high energy electrons which already have been used to generate synchrotron radiation on a compact scale. Exploiting the scattering induced by a second laser, one can further enhance the energy and number of photons produced provided the problems of synchronisation and compact γ-ray detection are solved. Here, we report on the work that has been done in developing an all-optical and hence, compact non-linear Thomson scattering source, including the new methods of synchronisation and compact γ-ray detection. We present evidence of the generation of multi-MeV (maximum 16-18 MeV) and ultra-high brilliance (exceeding 1020 photons s-1mm-2mrad-2 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above.

  15. Measurements of Ionic Structure in Shock Compressed Lithium Hydride from Ultra-fast X-ray Thomson Scattering

    SciTech Connect

    Kritcher, A L; Neumayer, P; Brown, C; Davis, P; Doppner, T; Falcone, R W; Gericke, D O; Gregori, G; Holst, B; Landen, O L; Lee, H J; Morse, E C; Pelka, A; Redmer, R; Roth, M; Vorberger, J; Wunsch, K; Glenzer, S H

    2009-07-14

    We present the first ultrafast temporally, spectrally and angularly resolved x-ray scattering measurements from shock-compressed matter. These laser-compressed lithium-hydride samples are well characterized by inelastic Compton and Plasmon scattering of a K-{alpha} x-ray probe providing independent measurements of temperature and density. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for ionic screening.

  16. Demonstration of improvement in the signal-to-noise ratio of Thomson scattering signal obtained by using a multi-pass optical cavity on the Tokyo Spherical Tokamak-2

    SciTech Connect

    Togashi, H. Ejiri, A.; Nakamura, K.; Takase, Y.; Yamaguchi, T.; Furui, H.; Imamura, K.; Inada, T.; Nakanishi, A.; Oosako, T.; Shinya, T.; Tsuda, S.; Tsujii, N.; Hiratsuka, J.; Kakuda, H.; Sonehara, M.; Wakatsuki, T.; Hasegawa, M.; Nagashima, Y.; Narihara, K.; and others

    2014-11-15

    The multi-pass Thomson scattering (TS) scheme enables obtaining many photons by accumulating multiple TS signals. The signal-to-noise ratio (SNR) depends on the accumulation number. In this study, we performed multi-pass TS measurements for ohmically heated plasmas, and the relationship between SNR and the accumulation number was investigated. As a result, improvement of SNR in this experiment indicated similar tendency to that calculated for the background noise dominant situation.

  17. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

    NASA Astrophysics Data System (ADS)

    Fletcher, L. B.; Zastrau, U.; Galtier, E.; Gamboa, E. J.; Goede, S.; Schumaker, W.; Ravasio, A.; Gauthier, M.; MacDonald, M. J.; Chen, Z.; Granados, E.; Lee, H. J.; Fry, A.; Kim, J. B.; Roedel, C.; Mishra, R.; Pelka, A.; Kraus, D.; Barbrel, B.; Döppner, T.; Glenzer, S. H.

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  18. Suppression of spurious mode oscillation in mega-watt 77-GHz gyrotron as a high quality probe beam source for the collective Thomson scattering in LHD

    SciTech Connect

    Ogasawara, S.; Kubo, S.; Nishiura, M.; Tanaka, K.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Ito, S.; Takita, Y.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Tatematsu, Y.; Saito, T.; Minami, R.; Kariya, T.; Imai, T.

    2012-10-15

    Collective Thomson scattering (CTS) diagnostic requires a strong probing beam to diagnose a bulk and fast ion distribution function in fusion plasmas. A mega-watt gyrotron for electron cyclotron resonance heating is used as a probing beam in the large helical device. Spurious mode oscillations are often observed during the turning on/off phase of the modulation. The frequency spectra of the 77-GHz gyrotron output power have been measured, and then one of the spurious modes, which interferes with the CTS receiver system, is identified as the TE{sub 17,6} mode at the frequency of 74.7 GHz. The mode competition calculation indicates that the increase of the magnetic field strength at the gyrotron resonator can avoid such a spurious mode and excite only the main TE{sub 18,6} mode. The spurious radiation at the 74.7 GHz is experimentally demonstrated to be suppressed in the stronger magnetic field than that optimized for the high-power operation.

  19. Suppression of spurious mode oscillation in mega-watt 77-GHz gyrotron as a high quality probe beam source for the collective Thomson scattering in LHD.

    PubMed

    Ogasawara, S; Kubo, S; Nishiura, M; Tatematsu, Y; Saito, T; Tanaka, K; Shimozuma, T; Yoshimura, Y; Igami, H; Takahashi, H; Ito, S; Takita, Y; Kobayashi, S; Mizuno, Y; Okada, K; Minami, R; Kariya, T; Imai, T

    2012-10-01

    Collective Thomson scattering (CTS) diagnostic requires a strong probing beam to diagnose a bulk and fast ion distribution function in fusion plasmas. A mega-watt gyrotron for electron cyclotron resonance heating is used as a probing beam in the large helical device. Spurious mode oscillations are often observed during the turning on/off phase of the modulation. The frequency spectra of the 77-GHz gyrotron output power have been measured, and then one of the spurious modes, which interferes with the CTS receiver system, is identified as the TE(17,6) mode at the frequency of 74.7 GHz. The mode competition calculation indicates that the increase of the magnetic field strength at the gyrotron resonator can avoid such a spurious mode and excite only the main TE(18,6) mode. The spurious radiation at the 74.7 GHz is experimentally demonstrated to be suppressed in the stronger magnetic field than that optimized for the high-power operation.

  20. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    NASA Astrophysics Data System (ADS)

    Adamek, J.; Müller, H. W.; Silva, C.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Horacek, J.; Kurzan, B.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R.; Fernandes, H.; Figueiredo, H.

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  1. Comparison of multialkali and GaAs photocathode detectors for Joint European Torus edge light detection and ranging Thomson scattering profiles

    SciTech Connect

    Kempenaars, M.; Nielsen, P.; Pasqualotto, R.; Gowers, C.; Beurskens, M.

    2004-10-01

    The Joint European Torus (JET) tokamak has two light detection and ranging (LIDAR) Thomson scattering systems, one for the core and one dedicated to the edge T{sub e} and n{sub e} profiles. The LIDAR scheme is unique to JET and is envisaged for use on ITER. The system's spatial resolution is defined by the convolution product of its components: laser pulse duration, detector response time, and digitizer speed. The original multialkali photocathode microchannel plate photomultipliers dictated the response time, resulting in a 12 cm spatial resolution along the line of sight. In the edge LIDAR system, this is improved by aligning the line of sight with the flux surfaces, thus improving the effective spatial resolution to 2 cm depending on the plasma configuration. To meet demands for better edge gradient resolution, an upgrade to higher quantum efficiency detectors was proposed. Four GaAs photocathode detectors have been procured, two of which surpass expectations. These detectors are shown to have a more than two times higher effective quantum efficiency and their response time is at least twice as fast as the multialkali detectors. Combined with a fast digitizer this improves the spatial resolution by a factor of two, down to one centimeter effective, depending on plasma configuration.

  2. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes.

    PubMed

    Adamek, J; Müller, H W; Silva, C; Schrittwieser, R; Ionita, C; Mehlmann, F; Costea, S; Horacek, J; Kurzan, B; Bilkova, P; Böhm, P; Aftanas, M; Vondracek, P; Stöckel, J; Panek, R; Fernandes, H; Figueiredo, H

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8. PMID:27131677

  3. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes.

    PubMed

    Adamek, J; Müller, H W; Silva, C; Schrittwieser, R; Ionita, C; Mehlmann, F; Costea, S; Horacek, J; Kurzan, B; Bilkova, P; Böhm, P; Aftanas, M; Vondracek, P; Stöckel, J; Panek, R; Fernandes, H; Figueiredo, H

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  4. Design of practical alignment device in KSTAR Thomson diagnostic

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Lee, S. H.; Yamada, I.

    2016-11-01

    The precise alignment of the laser path and collection optics in Thomson scattering measurements is essential for accurately determining electron temperature and density in tokamak experiments. For the last five years, during the development stage, the KSTAR tokamak's Thomson diagnostic system has had alignment fibers installed in its optical collection modules, but these lacked a proper alignment detection system. In order to address these difficulties, an alignment verifying detection device between lasers and an object field of collection optics is developed. The alignment detection device utilizes two types of filters: a narrow laser band wavelength for laser, and a broad wavelength filter for Thomson scattering signal. Four such alignment detection devices have been successfully developed for the KSTAR Thomson scattering system in this year, and these will be tested in KSTAR experiments in 2016. In this paper, we present the newly developed alignment detection device for KSTAR's Thomson scattering diagnostics.

  5. Injectors for Multipoint Injection

    NASA Technical Reports Server (NTRS)

    Prociw, Lev Alexander (Inventor); Ryon, Jason (Inventor)

    2015-01-01

    An injector for a multipoint combustor system includes an inner air swirler which defines an interior flow passage and a plurality of swirler inlet ports in an upstream portion thereof. The inlet ports are configured and adapted to impart swirl on flow in the interior flow passage. An outer air cap is mounted outboard of the inner swirler. A fuel passage is defined between the inner air swirler and the outer air cap, and includes a discharge outlet between downstream portions of the inner air swirler and the outer air cap for issuing fuel for combustion. The outer air cap defines an outer air circuit configured for substantially unswirled injection of compressor discharge air outboard of the interior flow passage.

  6. Influence of the electron velocity spread and the beam width on the efficiency and mode competition in the high-power pulsed gyrotron for 300 GHz band collective Thomson scattering diagnostics in the large helical device

    NASA Astrophysics Data System (ADS)

    Dumbrajs, O.; Saito, T.; Tatematsu, Y.; Yamaguchi, Y.

    2016-09-01

    We present results of a theoretical study of influence of the electron velocity spread and the radial width on the efficiency and mode competition in a 300-kW, 300-GHz gyrotron operating in the T E22 ,2 mode. This gyrotron was developed for application to collective Thomson scattering diagnostics in the large helical device and 300-kW level high power single T E22 ,2 mode oscillation has been demonstrated [Yamaguchi et al., J. Instrum. 10, c10002 (2015)]. Effects of a finite voltage rise time corresponding to the real power supply of this gyrotron are also considered. Simulations tracking eight competing modes show that the electron velocity spread and the finite beam width influence not only the efficiency of the gyrotron operation but also the mode competition scenario during the startup phase. A combination of the finite rise time with the electron velocity spread or the finite beam width affects the mode competition scenario. The simulation calculation reproduces the experimental observation of high power single mode oscillation of the T E22 ,2 mode as the design mode. This gives a theoretical basis of the experimentally obtained high power oscillation with the design mode in a real gyrotron and moreover shows a high power oscillation regime of the design mode.

  7. The SPARC_LAB Thomson source

    NASA Astrophysics Data System (ADS)

    Vaccarezza, C.; Alesini, D.; Anania, M. P.; Bacci, A.; Biagioni, A.; Bisesto, F.; Bellaveglia, M.; Cardarelli, P.; Cardelli, F.; Cianchi, A.; Chiadroni, E.; Croia, M.; Curcio, A.; Delogu, P.; Giovenale, D. Di; Domenico, G. Di; Pirro, G. Di; Drebot, I.; Ferrario, M.; Filippi, F.; Gallo, A.; Galletti, M.; Gambaccini, M.; Giribono, A.; Golosio, B.; Li, W.; Mostacci, A.; Oliva, P.; Palmer, D.; Petrillo, V.; Petrarca, M.; Pioli, S.; Piersanti, L.; Pompili, R.; Romeo, S.; Rossi, A. R.; Scifo, J.; Serafini, L.; Suliman, G.; Villa, F.

    2016-09-01

    The SPARC_LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges between 30 and 150 MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5 J with pulse lengths in the 25 fs-10 ps range, this provides an X-ray energy tunability in the range of 20-500 keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.

  8. SLM-based multipoint vibrometry

    NASA Astrophysics Data System (ADS)

    Haist, Tobias; Tarbeyevskaya, Alena; Warber, Michael; Osten, Wolfgang; Rembe, Christian; Ludwig, Mario; Stork, Wilhelm

    2011-05-01

    Heterodyne interferometry is a very accurate and robust technique for measuring vibrations under industrial conditions. Typically, instruments based on this principle measure on a single point and scanning is employed to obtain operational deflection shapes. For the simultaneous measurement of vibrations (e.g. to detect transients) it is possible to use a fixed arrangement of measurement beams. Dynamic steering of multiple beams, however, is not easy to achieve. In this contribution we present a solution for multipoint vibrometry using a high resolution (HDTV) programmable spatial light modulator as the core element. By using a liquid crystal display (LCD) for displaying a dynamic hologram it is possible to independently control multiple measurement spots in three dimensions with high repeatability and accuracy. Mechanical movements that might introduce noise do not oocur. The main challenge in designing such an LCD-based multipoint vibrometer is to avoid problems due to the unwanted spurious diffraction orders that will be present when using commercially available spatial light modulators for reconstructing holograms. We present a system in which the illuminating as well as the detection is programmable. One half of the high resolution LCD is used for illumination and the other half is responsible for the detection. Different possible methods to avoid spurious diffraction orders are shortly discussed. Emphasis will be laid on a method based on complex multiplexing (using hologram optimization) and a spatial multiplexing method based on Golay arrays. We show the optical design as well as first experimental results for a single detector. Hologram computation is based on a joint optimization of the detection and the illumination hologram using a modified Gerchberg-Saxton algorithm together with combinatorial optimization of the spot/detector mapping.

  9. Optimizing Thomson's jumping ring

    NASA Astrophysics Data System (ADS)

    Tjossem, Paul J. H.; Brost, Elizabeth C.

    2011-04-01

    The height to which rings will jump in a Thomson jumping ring apparatus is the central question posed by this popular lecture demonstration. We develop a simple time-averaged inductive-phase-lag model for the dependence of the jump height on the ring material, its mass, and temperature and apply it to measurements of the jump height for a set of rings made by slicing copper and aluminum alloy pipe into varying lengths. The data confirm a peak jump height that grows, narrows, and shifts to smaller optimal mass when the rings are cooled to 77 K. The model explains the ratio of the cooled/warm jump heights for a given ring, the reduction in optimal mass as the ring is cooled, and the shape of the mass resonance. The ring that jumps the highest is found to have a characteristic resistance equal to the inductive reactance of the set of rings.

  10. Multipoint study of interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Blanco-Cano, Xochitl; Kajdic, Primoz; Russell, Christopher T.; Aguilar-Rodriguez, Ernesto; Jian, Lan K.; Luhmann, Janet G.

    2016-04-01

    Interplanetary (IP) shocks are driven in the heliosphere by Interplanetary Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs). These shocks perturb the solar wind plasma, and play an active role in the acceleration of ions to suprathermal energies. Shock fronts evolve as they move from the Sun. Their surfaces can be far from uniform and be modulated by changes in the ambient solar wind (magnetic field orientation, flow velocity), shocks rippling, and perturbations upstream and downstream from the shocks, i.e., electromagnetic waves. In this work we use multipoint observations from STEREO, WIND, and MESSENGER missions to study shock characteristics at different helio-longitudes and determine the properties of the waves near them. We also determine shock longitudinal extensions and foreshock sizes. The variations of geometry along the shock surface can result in different extensions of the wave and ion foreshocks ahead of the shocks, and in different wave modes upstream and downtream of the shocks. We find that the ion foreshock can extend up to 0.2 AU ahead of the shock, and that the upstream region with modified solar wind/waves can be very asymmetric.

  11. EDITORIAL: J J Thomson's Electron

    NASA Astrophysics Data System (ADS)

    Adams, Steve

    1997-07-01

    Westminster School, London, UK A few weeks ago David Thomson, J J Thomson's grandson, presented a Friday evening discourse at the Royal Institution. In it he traced the development of JJT's life from his early studies at Owen's College in Manchester, on to Trinity College Cambridge, his work under Rayleigh at the Cavendish, and his succession as Professor of Experimental Physics in 1884 (a post he passed on to Rutherford in 1919). These were years of heroic discoveries that shaped 20th century physics. Looking around the lecture theatre at all the bow-ties and dinner jackets, it must have been rather similar on 30 April 1897 when JJT delivered his famous discourse on 'Cathode Rays' in which he cautiously but confidently announced that his own results together with those of other experimenters (Lenard in particular):

    `....seem to favour the hypothesis that the carriers of the charges are smaller than the atoms of hydrogen.'
    In this issue articles by Leif Gerward and Christopher Cousins, and by Isobel Falconer explore the historical and philosophical context of that discovery. The sound-bites to history in many A-level courses have JJT as both the hero who single-handedly discovered the electron and the rather naive Victorian scientist who thought the atom was a plum pudding. It is valuable to see how Thomson's work pulled the threads of many experiments together and to realize that he may have been first to the post because of a difference in the philosophical approach to cathode rays in Britain compared to Europe. Experimental data must always be interpreted, and divergent philosophies can lead to quite different conclusions. The electron was, of course, the first subatomic particle to be identified. Christine Sutton's article looks at how 20th century discoveries reveal Nature's mysterious habit of repeating successful patterns---electrons for example have very close relations, the muon and the tau---but why? Perhaps the answer will come

  12. A compact multichannel spectrometer for Thomson scatteringa)

    NASA Astrophysics Data System (ADS)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R.

    2012-10-01

    The availability of high-efficiency volume phase holographic (VPH) gratings and intensified CCD (ICCD) cameras have motivated a simplified, compact spectrometer for Thomson scattering detection. Measurements of Te < 100 eV are achieved by a 2971 l/mm VPH grating and measurements Te > 100 eV by a 2072 l/mm VPH grating. The spectrometer uses a fast-gated (˜2 ns) ICCD camera for detection. A Gen III image intensifier provides ˜45% quantum efficiency in the visible region. The total read noise of the image is reduced by on-chip binning of the CCD to match the 8 spatial channels and the 10 spectral bins on the camera. Three spectrometers provide a minimum of 12 spatial channels and 12 channels for background subtraction.

  13. THE THOMSON SURFACE. III. TRACKING FEATURES IN 3D

    SciTech Connect

    Howard, T. A.; DeForest, C. E.; Tappin, S. J.; Odstrcil, D.

    2013-03-01

    In this, the final installment in a three-part series on the Thomson surface, we present simulated observations of coronal mass ejections (CMEs) observed by a hypothetical polarizing white light heliospheric imager. Thomson scattering yields a polarization signal that can be exploited to locate observed features in three dimensions relative to the Thomson surface. We consider how the appearance of the CME changes with the direction of trajectory, using simulations of a simple geometrical shape and also of a more realistic CME generated using the ENLIL model. We compare the appearance in both unpolarized B and polarized pB light, and show that there is a quantifiable difference in the measured brightness of a CME between unpolarized and polarized observations. We demonstrate a technique for using this difference to extract the three-dimensional (3D) trajectory of large objects such as CMEs. We conclude with a discussion on how a polarizing heliospheric imager could be used to extract 3D trajectory information about CMEs or other observed features.

  14. Scalar discrete nonlinear multipoint boundary value problems

    NASA Astrophysics Data System (ADS)

    Rodriguez, Jesus; Taylor, Padraic

    2007-06-01

    In this paper we provide sufficient conditions for the existence of solutions to scalar discrete nonlinear multipoint boundary value problems. By allowing more general boundary conditions and by imposing less restrictions on the nonlinearities, we obtain results that extend previous work in the area of discrete boundary value problems [Debra L. Etheridge, Jesus Rodriguez, Periodic solutions of nonlinear discrete-time systems, Appl. Anal. 62 (1996) 119-137; Debra L. Etheridge, Jesus Rodriguez, Scalar discrete nonlinear two-point boundary value problems, J. Difference Equ. Appl. 4 (1998) 127-144].

  15. Multi-Point Combustion System: Final Report

    NASA Technical Reports Server (NTRS)

    Goeke, Jerry; Pack, Spencer; Zink, Gregory; Ryon, Jason

    2014-01-01

    A low-NOx emission combustor concept has been developed for NASA's Environmentally Responsible Aircraft (ERA) program to meet N+2 emissions goals for a 70,000 lb thrust engine application. These goals include 75 percent reduction of LTO NOx from CAEP6 standards without increasing CO, UHC, or smoke from that of current state of the art. An additional key factor in this work is to improve lean combustion stability over that of previous work performed on similar technology in the early 2000s. The purpose of this paper is to present the final report for the NASA contract. This work included the design, analysis, and test of a multi-point combustion system. All design work was based on the results of Computational Fluid Dynamics modeling with the end results tested on a medium pressure combustion rig at the UC and a medium pressure combustion rig at GRC. The theories behind the designs, results of analysis, and experimental test data will be discussed in this report. The combustion system consists of five radially staged rows of injectors, where ten small scale injectors are used in place of a single traditional nozzle. Major accomplishments of the current work include the design of a Multipoint Lean Direct Injection (MLDI) array and associated air blast and pilot fuel injectors, which is expected to meet or exceed the goal of a 75 percent reduction in LTO NOx from CAEP6 standards. This design incorporates a reduced number of injectors over previous multipoint designs, simplified and lightweight components, and a very compact combustor section. Additional outcomes of the program are validation that the design of these combustion systems can be aided by the use of Computational Fluid Dynamics to predict and reduce emissions. Furthermore, the staging of fuel through the individually controlled radially staged injector rows successfully demonstrated improved low power operability as well as improvements in emissions over previous multipoint designs. Additional comparison

  16. Thomson semiconductors introduces products, balances books

    NASA Astrophysics Data System (ADS)

    Carrasco, R.

    1985-10-01

    Product development at Thomson is discussed. Tono lines are featured. The VME line which consists of about 20 broads, plus software and systems. And the G64 line. Economic analysis and marketing strategy is also briefly discussed.

  17. Amplified OTDR Systems for Multipoint Corrosion Monitoring

    PubMed Central

    Nascimento, Jehan F.; Silva, Marcionilo J.; Coêlho, Isnaldo J. S.; Cipriano, Eliel; Martins-Filho, Joaquim F.

    2012-01-01

    We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. PMID:22737017

  18. Narrowband Emission in Compton/Thomson Sources Operating in the High-Field Regime

    DOE PAGESBeta

    Terzic, Balsa; Deitrick, Kirsten E.; Hofler, Alicia S.; Kraff, Geoffrey A.

    2014-02-21

    We present a novel and quite general analysis of the interaction of a high-field chirped laser pulse and a relativistic electron, in which exquisite control of the spectral brilliance of the upshifted Thomson-scattered photon is shown to be possible. Normally, when Thomson scattering occurs at high field strengths, there is ponderomotive line broadening in the scattered radiation. This effect makes the bandwidth too large for some applications, and reduces the spectral brilliance. In this paper we show that such broadening can be corrected and eliminated by suitable frequency modulation of the incident laser pulse. Further, we suggest a practical realizationmore » of this compensation idea in terms of a chirped-beam driven FEL oscillator configuration, and show that significant compensation can occur, even with the imperfect matching to be expected in these conditions.« less

  19. Narrowband Emission in Compton/Thomson Sources Operating in the High-Field Regime

    SciTech Connect

    Terzic, Balsa; Deitrick, Kirsten E.; Hofler, Alicia S.; Kraff, Geoffrey A.

    2014-02-21

    We present a novel and quite general analysis of the interaction of a high-field chirped laser pulse and a relativistic electron, in which exquisite control of the spectral brilliance of the upshifted Thomson-scattered photon is shown to be possible. Normally, when Thomson scattering occurs at high field strengths, there is ponderomotive line broadening in the scattered radiation. This effect makes the bandwidth too large for some applications, and reduces the spectral brilliance. In this paper we show that such broadening can be corrected and eliminated by suitable frequency modulation of the incident laser pulse. Further, we suggest a practical realization of this compensation idea in terms of a chirped-beam driven FEL oscillator configuration, and show that significant compensation can occur, even with the imperfect matching to be expected in these conditions.

  20. Joule-Thomson expander and heat exchanger

    NASA Technical Reports Server (NTRS)

    Norman, R. H.

    1976-01-01

    The Joule-Thomson Expander and Heat Exchanger Program was initiated to develop an assembly (JTX) which consists of an inlet filter, counterflow heat exchanger, Joule-Thomson expansion device, and a low pressure jacket. The program objective was to develop a JTX which, when coupled to an open cycle supercritical helium refrigerating system (storage vessel), would supply superfluid helium (He II) at 2 K or less for cooling infrared detectors.

  1. Thomson parabola ion energy analyzer

    SciTech Connect

    Cobble, James A; Flippo, Kirk A; Letzring, Samuel A; Lopez, Frank E; Offermann, Dustin T; Oertel, John A; Mastrosimone, Dino

    2010-01-01

    A new, versatile Thomson parabola ion energy (TPIE) analyzer has been designed and constructed for use at the OMEGA-EP facility. Multi-MeV ions from EP targets are transmitted through a W pinhole into a (5- or 8-kG) magnetic field and subsequently through a parallel electric field of up to 30 kV/cm. The ion drift region may have a user-selected length of 10, 50, or 80 cm. With the highest fields, 500-Me V C{sup 6+} and C{sup 5+} may be resolved. TPIE is TIM-mounted at OMEGA-EP and is qualified in all existing TIMs. The instrument runs on pressure-interlocked 15-VDC power available in EP TIM carts. It may be inserted to within several inches of the target to attain sufficient flux for a measurement. For additional flux control, the user may select a square-aperture W pinhole of 0.004-inch or 0.010-inch. The detector consists of CR-39 backed by an image plate. The fully relativistic design code and design features are discussed. Ion spectral results from first use at OMEGA-EP are expected.

  2. William Thomson and Joseph Janvier Woodward.

    PubMed

    Zimmerman, L E

    1995-01-01

    William Thomson and Joseph Janvier Woodward were two of several exceptionally versatile and highly productive young physicians who volunteered for service with the Union Army at the outbreak of the Civil War, and then were subsequently assigned to the Washington Area where they played significant roles and made major contributions towards the development of the Army Medical Museum. Both pioneered in photomicrography. While Thomson deserves priority, Woodward was the more prolific contributor whose work and publications helped draw attention to the Army Medical Museum as a center for excellence in pathology. After the War Thomson returned to Philadelphia where his interests in photography stimulated his pursuit of optics and eventually his becoming one of the first American physicians to specialize in ophthalmology. He became Professor of Ophthalmology at Jefferson Medical College.

  3. Reliable Wireless Broadcast with Linear Network Coding for Multipoint-to-Multipoint Real-Time Communications

    NASA Astrophysics Data System (ADS)

    Kondo, Yoshihisa; Yomo, Hiroyuki; Yamaguchi, Shinji; Davis, Peter; Miura, Ryu; Obana, Sadao; Sampei, Seiichi

    This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for ad-hoc networks like video game networks. We aim to achieve highly reliable MPtoMP broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the encoded packet is broadcasted in the next sequence as a piggy-back for its native packet. To prevent increase of overhead in each packet due to piggy-back packet transmission, network coding vector for each node is exchanged between all nodes in the negotiation phase. Each user keeps using the same coding vector generated in the negotiation phase, and only coding information that represents which user signal is included in the network coding process is transmitted along with the piggy-back packet. Our simulation results show that the proposed method can provide higher reliability than other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with a practical degree of complexity when installed on current wireless devices.

  4. An analytic formula for the relativistic incoherent Thomson backscattering spectrum for a drifting bi-Maxwellian plasma

    SciTech Connect

    Naito, O.

    2015-08-15

    An analytic formula has been derived for the relativistic incoherent Thomson backscattering spectrum for a drifting anisotropic plasma when the scattering vector is parallel to the drifting direction. The shape of the scattering spectrum is insensitive to the electron temperature perpendicular to the scattering vector, but its amplitude may be modulated. As a result, while the measured temperature correctly represents the electron distribution parallel to the scattering vector, the electron density may be underestimated when the perpendicular temperature is higher than the parallel temperature. Since the scattering spectrum in shorter wavelengths is greatly enhanced by the existence of drift, the diagnostics might be used to measure local electron current density in fusion plasmas.

  5. A variational proof of Thomson's theorem

    NASA Astrophysics Data System (ADS)

    Fiolhais, Miguel C. N.; Essén, Hanno; Gouveia, Tomé M.

    2016-08-01

    Thomson's theorem of electrostatics, which states the electric charge on a set of conductors distributes itself on the conductor surfaces to minimize the electrostatic energy, is reviewed in this letter. The proof of Thomson's theorem, based on a variational principle, is derived for a set of normal charged conductors, with and without the presence of external electric fields produced by fixed charge distributions. In this novel approach, the variations are performed on both the charge densities and electric potentials, by means of a local Lagrange multiplier associated with Poisson's equation, constraining the two variables.

  6. Genetics Home Reference: Rothmund-Thomson syndrome

    MedlinePlus

    ... risk of developing cancer, particularly a form of bone cancer called osteosarcoma. These bone tumors most often develop during childhood ... Rothmund-Thomson syndrome MedlinePlus Encyclopedia: Cataract MedlinePlus Encyclopedia: Osteosarcoma These resources from MedlinePlus offer information about the ...

  7. Convergence of multipoint Pade approximants of piecewise analytic functions

    SciTech Connect

    Buslaev, Viktor I

    2013-02-28

    The behaviour as n{yields}{infinity} of multipoint Pade approximants to a function which is (piecewise) holomorphic on a union of finitely many continua is investigated. The convergence of multipoint Pade approximants is proved for a function which extends holomorphically from these continua to a union of domains whose boundaries have a certain symmetry property. An analogue of Stahl's theorem is established for two-point Pade approximants to a pair of functions, either of which is a multivalued analytic function with finitely many branch points. Bibliography: 11 titles.

  8. Analysis and Multipoint Design of the TCA Concept

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Buning, Pieter G.

    1999-01-01

    The goal in this effort is to analyze the baseline TCA concept at transonic and supersonic cruise, then apply the natural flow wing design concept to obtain multipoint performance improvements. Analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between the overset grids.

  9. Fabrication of multipoint light emitting optical fibers for optogenetics

    NASA Astrophysics Data System (ADS)

    Sileo, Leonardo; Pisanello, Marco; De Vittorio, Massimo; Pisanello, Ferruccio

    2015-03-01

    Multipoint Light Emitting Optical Fibers (MPF) has been recently demonstrated as a versatile tool for spatially addressable optogenetics experiments. Their fabrication has been possible thanks to a number of key microfabrication technologies, in particular the unique nanofabrication capabilities of a Focused Ion Beam. This work provides the complete description of MPF fabrication, detailing the optimization process for each fabrication step.

  10. Ultrafast Materials Probing with the LLNL Thomson X-Ray Source

    SciTech Connect

    Springer, P; Anderson, S; Brown, W; Barty, C; Cauble, R; Crane, J; Cynn, H; Ebbers, C; Fittinghoff, D; Gibson, D; Hartemann, F; Javanovich, I; Kuba, J; LeSage, G; McMahan, A; Minich, R; Moriarty, J; Remington, B; Slaughter, D; Steitz, F H; Tremaine, A; Yoo, C-s; Rosenzweig, J; Ditmire, T

    2002-09-03

    The use of short laser pulses to generate very high brightness, ultra short (fs to ps) x-ray pulses is a topic of great interest. In principle, fantosecond-scale pump-probe experiments can be used to temporally resolve structural dynamics of materials on the time scale of atomic motion. The development of sub-ps x-ray pulses will make possible a wide range of materials and plasma physics studies with unprecedented time resolution. The Thomson scattering project at LLNL will provide such a novel x-ray source of high power using short laser pulses and a high brightness, relativistic electron bunch. The system is based on a 5mm-mrad normalized emittance photoinjector, 100 MeV electron RF linac, and a 300 mJ, 35 fs solid-state laser system. The Thomson source will produce ultra fast pulses with x-ray energies (60 kev) capable of probing into high-Z metals.

  11. Multipulse Thomson scattering system for the National Spherical Torus Experiment

    SciTech Connect

    Johnson, D.; Bretz, N.; LeBlanc, B.; Palladino, R.; Long, D.; Parsells, R.

    1999-01-01

    A design using a backscattering geometry is presented, which emphasizes high sensitivity and high spatial resolution at the outer edge of the National Spherical Torus Experiment, while providing full profile capability with a moderate number of channels. The design is based on Nd:YAG lasers and avalanche photodiode detectors to allow for high repetition rate measurements. {copyright} {ital 1999 American Institute of Physics.}

  12. Parametric and nonparametric linkage analysis: A unified multipoint approach

    SciTech Connect

    Kruglyak, L.; Daly, M.J.; Reeve-Daly, M.P.; Lander, E.S.

    1996-06-01

    In complex disease studies, it is crucial to perform multipoint linkage analysis with many markers and to use robust nonparametric methods that take account of all pedigree information. Currently available methods fall short in both regards. In this paper, we describe how to extract complete multipoint inheritance information from general pedigrees of moderate size. This information is captured in the multipoint inheritance distribution, which provides a framework for a unified approach to both parametric and nonparametric methods of linkage analysis. Specifically, the approach includes the following: (1) Rapid exact computation of multipoint LOD scores involving dozens of highly polymorphic markers, even in the presence of loops and missing data. (2) Nonparametric linkage (NPL) analysis, a powerful new approach to pedigree analysis. We show that NPL is robust to uncertainty about mode of inheritance, is much more powerful than commonly used nonparametric methods, and loses little power relative to parametric linkage analysis. NPL thus appears to be the method of choice for pedigree studies of complex traits. (3) Information-content mapping, which measures the fraction of the total inheritance information extracted by the available marker data and points out the regions in which typing additional markers is most useful. (4) Maximum-likelihood reconstruction of many-marker haplotypes, even in pedigrees with missing data. We have implemented NPL analysis, LOD-score computation, information-content mapping, and haplotype reconstruction in a new computer package, GENEHUNTER. The package allows efficient multipoint analysis of pedigree data to be performed rapidly in a single user-friendly environment. 34 refs., 9 figs., 2 tabs.

  13. Manganese Nitride Sorption Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Phillips, Wayne M.

    1992-01-01

    Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

  14. J. J. Thomson goes to America.

    PubMed

    Downard, Kevin M

    2009-11-01

    Joseph John (J. J.) Thomson was an accomplished scientist who helped lay the foundations of nuclear physics. A humble man of working class roots, Thomson went on to become one of the most influential physicists of the late 19th century. He is credited with the discovery of the electron, received a Nobel Prize in physics in 1906 for investigations into the conduction of electricity by gases, was knighted in 1908, and served as a Cavendish Professor and Director of the laboratory for over 35 years from 1884. His laboratory attracted some of the world's brightest minds; Francis W. Aston, Niels H. D. Bohr, Hugh L. Callendar, Charles T. R. Wilson, Ernest Rutherford, George F. C. Searle, Geoffrey I. Taylor, and John S. E. Townsend all worked under him. This article recounts J. J. Thomson's visits to North America in 1896, 1903, 1909, and finally 1923. It presents his activities and his personal impressions of the people and society of the U.S.A. and Canada, and the science of atomic physics and chemistry in the late 1800s and early 1900s.

  15. Joule-Thomson Cooler Produces Nearly Constant Temperature

    NASA Technical Reports Server (NTRS)

    Bard, Steven; Wu, Jiunn-Jeng; Trimble, Curtis A.

    1992-01-01

    Improved Joule-Thomson cooler maintains nearly constant temperature. Absolute-pressure relief valve helps stabilize temperature of cold head despite variations in atmospheric pressure. Feedback-controlled electrical heater provides additional stabilization. Demand-flow Joule-Thomson valve requires less nitrogen than fixed-orifice Joule-Thomson valve providing same amount of cooling. Provides stable low temperatures required for operation of such devices as tunable diode lasers in laboratory and balloon-borne instruments detecting contaminants in atmosphere.

  16. Multipoint Observations of Magnetospheric Processes Relevant to the Substorm Events

    NASA Astrophysics Data System (ADS)

    Sibeck, D. G.; Gutynska, O.; Fok, M. C. H.

    2015-12-01

    We present several case studies of simultaneous multipoint observations of hot ion (~30-2200 keV) injections that occur during substorms in the day- and night-side of magnetosphere from THEMIS, RBSP and MMS probes. We complement them with observations of magnetic field signatures to estimate time delays of earthward plasma flows at multiple probes. We discuss the mechanisms that trigger substorm onset comparing the observations with inner plasma sheet simulations.

  17. Multipoint mapping calculations for sperm-typing data

    SciTech Connect

    Lazzeroni, L.C.; Lange, K.; Arnheim, N.; Schmitt, K.

    1994-09-01

    This paper explains how multipoint likelihoods can be computed for sperm-typing data. Experimental errors such as multiple sperm per tube, inadequate amplification, and contamination by exogenous DNA are explicitly taken into account. By limiting the number of sperm theoretically possible per tube to a predetermined maximum and by assuming no chiasma interference, maximum-likelihood estimation can be carried out rapidly using the theory of hidden Markov chains. 14 refs., 2 tabs.

  18. Integrated Multipoint-Laser Endoscopic Airway Measurements by Transoral Approach

    PubMed Central

    Neitsch, Marie; Horn, Iris-Susanne; Hofer, Mathias; Dietz, Andreas; Fischer, Miloš

    2016-01-01

    Objectives. Optical and technical characteristics usually do not allow objective endoscopic distance measurements. So far no standardized method for endoscopic distance measurement is available. The aim of this study was to evaluate the feasibility and accuracy of transoral airway measurements with a multipoint-laser endoscope. Methods. The semirigid endoscope includes a multipoint laser measurement system that projects 49 laser points (wavelength 639 nm, power < 5 mW) into the optical axis of the endoscopic view. Distances, areas, and depths can be measured in real-time. Transoral endoscopic airway measurements were performed on nine human cadavers, which were correlated with CT measurements. Results. The preliminary experiment showed an optimum distance between the endoscope tip and the object of 5 to 6 cm. There was a mean measurement error of 3.26% ± 2.53%. A Spearman correlation coefficient of 0.95 (p = 0.01) was calculated for the laryngeal measurements and of 0.93 (p < 0.01) for the tracheal measurements compared to the CT. Using the Bland-Altman-Plot, the 95% limits of agreement for the laryngeal measurements were satisfactory: −0.76 and 0.93. Conclusions. Integrated multipoint-laser endoscopic measurement is a promising technical supplement, with potential use in diagnostic endoscopy and transoral endoscopic surgery in daily practice. PMID:27022612

  19. John Thomson: Photojournalist in Asia, 1862-1872.

    ERIC Educational Resources Information Center

    Parker, Elliott S.

    John Thomson was a nineteenth-century British photojournalist who used the wet-plate process to illustrate his explorations of eastern and Southeast Asia. His travels from 1862 to 1872 took him to the following places, among others: Ceylon, Cambodia, Singapore, Thailand, Saigon, Siam, mainland China, and Taiwan. Thomson chose to use the wet-plate…

  20. Thomson's Theorem of Electrostatics: Its Applications and Mathematical Verification

    ERIC Educational Resources Information Center

    Bakhoum, Ezzat G.

    2008-01-01

    A 100 years-old formula that was given by J. J. Thomson recently found numerous applications in computational electrostatics and electromagnetics. Thomson himself never gave a proof for the formula; but a proof based on Differential Geometry was suggested by Jackson and later published by Pappas. Unfortunately, Differential Geometry, being a…

  1. New digital circuits at Thomson semiconductor in France

    NASA Astrophysics Data System (ADS)

    Dellamussia, J. P.

    1985-11-01

    DCS, Thomson Semiconductors' Semi-Standard Circuits Department, has just announced a CMOS gate array with up to 4,200 gates, standard cells, and a unique 900-component, 3 GHz linear gate array. All of Thomson's gate arrays are supported by Daisy, Valid and Mentor workstations. These are the first fruits of a reorganization begun several months ago to distance the department from the actual design and manufacture of integrated circuits, making it more of an archestrator among customers, workstation manufacturers, independent designers and the various Thomson Semiconductors division. Thomson Semiconductors' silicon sales based on DCS contracts totaled 25,000,000 Frances in 1984. This figure should be double in 1985. Thomson Semiconductors plans to offer 120 new integrated circuits this year, twice the number available in 1984. At the same time, the Munich design center and the American subsidiary, VSI, should open new markets in 1985, bringing exports to an estimated 30 percent of sales.

  2. Resonant Compton scattering and gamma-ray burst continuum spectra

    NASA Technical Reports Server (NTRS)

    Baring, M. G.

    1995-01-01

    The Thomson limit of resonant inverse Compton scattering in the strong magnetic fields of neutron stars is considered as a mechanism for producing gamma-ray burst continuum spectra. Photon production spectra and electron cooling rates are presented using the full magnetic Thomson cross-section. Model emission spectra are obtained as self-consistent solutions of a set of photon and electron kinetic equations, displaying spectral breaks and other structure at gamma-ray energies.

  3. Multicomponent gas sorption Joule-Thomson refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Bard, Steven (Inventor)

    1991-01-01

    The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

  4. Status of Thomson source at SPARC/PLASMONX

    NASA Astrophysics Data System (ADS)

    Bacci, A.; Broggi, F.; DeMartinis, C.; Giove, D.; Maroli, C.; Petrillo, V.; Rossi, A. R.; Serafini, L.; Tomassini, P.; Cultrera, L.; Di Pirro, G.; Ferrario, M.; Filippetto, D.; Gatti, G.; Pace, E.; Vaccarezza, C.; Vicario, C.; Bosi, F.; Giulietti, D.; Gizzi, L. A.; Oliva, P.

    2009-09-01

    The PLasma Acceleration and MONochromatic X-ray generation (PLASMONX) project foresees the installation at LNF of a 0.3 PW (6 J, 20 fs pulse) Ti:Sa laser system, named Frascati Laser for Acceleration and Multidisciplinary Experiments (FLAME), to operate in close connection with the existent SPARC electron photo-injector, allowing for advanced laser/e-beam interaction experiments. Among the foreseen scientific activities, a Thomson scattering experiment between the SPARC electron bunch and the high power laser will be performed. At the present time the linac has been tested and the electron beam characterized up to the maximum operating energy (150 MeV). The beam lines transporting the beam to the interaction chamber with the laser have been designed. The electron final focusing system, featuring a quadrupole triplet and large radius solenoid magnet (ensuring an e-beam waist of 5-10 μm) as well as the whole interaction chamber layout has been defined. The optical transfer line issues: transport up to the interaction; tight focusing; diagnostics and fine positioning; have been solved within the final design. The construction of the building hosting the laser has been completed; delivering and installation of the laser, as much of the beam lines elements will take place in the next months.

  5. Concept to diagnose mix with imaging x-ray Thomson scatteringa)

    NASA Astrophysics Data System (ADS)

    Keiter, Paul A.; Gamboa, Eliseo J.; Huntington, Channing M.; Kuranz, Carolyn C.

    2012-10-01

    Turbulent mixing of two fluid species is a ubiquitous problem, prevalent in systems such as inertial confinement fusion (ICF) capsule implosions, supernova remnants, and other astrophysical systems. In complex, high Reynolds number compressible high energy density (HED) flows such as these, hydrodynamic instabilities initiate the turbulent mixing process, which can then feedback and alter the mean hydrodynamic motion through nonlinear processes. In order to predict how these systems evolve under turbulent conditions, models are used. However, these models require detailed quantitative data to validate and constrain their detailed physics models as well as improve them. Providing this much needed data is currently at the forefront of HED research but is proving elusive due to a lack of available diagnostics capable of directly measuring detailed flow variables. Thomson scattering is a promising technique in this regard as it provides fundamental conditions of the flow (ρ, T, Zbar) due to its direct interaction with the small scales of the fluid or plasma and was recently considered as a possible mix diagnostic. With the development of imaging x-ray Thomson scattering (IXRTS) obtaining spatial profiles of these variables is within reach. We propose a novel use of the IXRTS technique that will provide more detailed quantitative data required for model validation in mix experiments.

  6. Updating multipoint simulations using the ensemble Kalman filter

    NASA Astrophysics Data System (ADS)

    Hu, L. Y.; Zhao, Y.; Liu, Y.; Scheepens, C.; Bouchard, A.

    2013-02-01

    In the last two decades, the multipoint simulation (MPS) method has been developed and increasingly used for building complex geological facies models that are conditioned to geological and geophysical data. In the meantime, the ensemble Kalman filter (EnKF) approach has been developed and recognized as a promising way for assimilating dynamic production data into reservoir models. So far, the EnKF approach is proven efficient for updating continuous model parameters that have a linear statistical relation with the flow responses. It remains challenging to extend the EnKF approach to updating complex geological facies models generated by MPS, while preserving their geological and statistical consistency. In this paper, we introduce a new method for parameterizing geostatistical reservoir models generated by MPS. It is mathematically proven that updating these parameters during a history matching process does not compromise the hard data conditioning and the geological and statistical consistency of the reservoir model defined by the training image and other information including global facies proportions, trend maps etc. This method is an alternative to the gradual deformation method but has an enlarged search space for covering possible solutions. Based on the above parameterization, we present two algorithms of using EnKF approach to update multipoint simulations to dynamic data. We also present results of using the above methodology to condition a sector model of a fluvial reservoir to dynamic data.

  7. The Joule-Thomson expansion coefficient by formula manipulation

    SciTech Connect

    Hirose, Y.; Kitazawa, T. ); Yoshida, T. . Faculty of Engineering)

    1990-07-01

    By use of formula manipulation, practical programs used to estimate the Joule-Thomson coefficients are presented in this paper. The available equations of state used include the following: van der Waals, Virial, BWR, RK, and SRK. The Joule-Thomson coefficients for nitrogen and ethane are estimated by the proposed programs, and their ability to reproduce experimental values is tested. It is found that the RK equation yields the best results for nitrogen and ethane despite its simplicity.

  8. POLIX: A Thomson X-ray polarimeter for a small satellite mission

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit; Gopala Krishna, M. R.; Puthiya Veetil, Rishin

    2016-07-01

    POLIX is a Thomson X-ray polarimeter for a small satellite mission of ISRO. The instrument consists of a collimator, a scatterer and a set proportional counters to detect the scattered X-rays. We will describe the design, specifications, sensitivity, and development status of this instrument and some of the important scientific goals. This instrument will provide unprecedented opportunity to measure X-ray polarisation in the medium energy range in a large number of sources of different classes with a minimum detectable linear polarisation degree of 2-3%. The prime objects for observation with this instrument are the X-ray bright accretion powered neutron stars, accreting black holes in different spectral states, rotation powered pulsars, magnetars, and active galactic nuclei. This instrument will be a bridge between the soft X-ray polarimeters and the Compton polarimeters.

  9. Mixed refrigerant Joule-Thomson sorption cryocoolers

    NASA Astrophysics Data System (ADS)

    Tzabar, Nir; Grossman, Gershon

    2014-01-01

    Joule-Thomson (JT) sorption cryocooling is the most mature technology for cooling from a normal Room-Temperature (RT) down to temperatures below 100 K in the absence of moving parts. Therefore, high reliability and no vibrations are attainable, in comparison with other cryocoolers. Cooling to 80 - 100 K with JT cryocoolers is often implemented with pure nitrogen. Alternatively, mixed refrigerants have been suggested for reducing the operating pressures to enable closed cycle cryocooling. There is a variety of publications describing nitrogen sorption cryocoolers with different configurations of sorption compressors. In the present research we suggest a novel sorption JT cryocooler that operates with a mixed refrigerant. Merging of sorption cryocooling and a mixed refrigerant enables the use of a simple, single stage compressor for cooling to 80 - 100 K, lower operating temperatures of the sorption cycle, and thus - reduced power consumption. In previous studies we have analyzed sorption compressors for mixed gases and mixed refrigerants for JT cryocoolers, separately. In this paper the option of mixed refrigerant sorption JT cryocoolers is explored. The considerations for developing mixed refrigerants to be driven by sorption compressors and to be utilized with JT cryocoolers are provided. It appears that, unlike with pure nitrogen, mixed refrigerants can be suitable for JT cryocooling with a single stage sorption compressor.

  10. Multipoint Observations of Oval-aligned Transpolar Arc Formation

    NASA Astrophysics Data System (ADS)

    Cumnock, J. A.; Le, G.; Zhang, Y.; Slavin, J. A.

    2013-12-01

    We analyze changes in field-aligned currents associated with auroral oval-aligned transpolar arc formation during quiet times on time scales of a few minutes. This is accomplished using observations from the highly accurate multipoint magnetic field measurements provided by the Space Technology 5 mission which consists of three micro-satellites in low Earth orbit. Simultaneous measurements of precipitating particles are provided by three DMSP satellites. We analyze field-aligned currents associated with the dusk oval. For the first time we observe the field-aligned currents associated with the formation of an oval-aligned transpolar arc poleward of the auroral oval which in one case are large compared with the field-aligned currents associated with the auroral oval measured 10 minutes earlier. These events clearly illustrate the dynamic nature of oval-aligned arc formation.

  11. Multipoint measurements of energetic particles in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Baker, D. N.

    1988-01-01

    The benefits of energetic-particle measurements in the study of magnetospheric physics are reviewed, including the particles' relative ease of detection, their high rectilinear speed, their range of gyroradii, and their immunity to large-scale electric fields. With such particles, it is possible to observationally separate distinctive plasma regions, uniquely assess field-line topologies, examine connectivity from the magnetospheric equator to the ionosphere, and sense global changes in magnetospheric configuration. Multipoint measurements of energetic particles have contributed substantially to the understanding of the earth magnetopause, the leakage of particles into the upstream region, the effect of sudden storm compressions, the global nature of substorm dynamics, and the location and character of high-energy acceleration processes.

  12. Rapid multipoint linkage analysis of recessive traits in nuclear families, including homozygosity mapping

    SciTech Connect

    Kruglyak, L.; Daly, M.J.; Lander, E.S. |

    1995-02-01

    Homozygosity mapping is a powerful strategy for mapping rare recessive traits in children of consanguineous marriages. Practical applications of this strategy are currently limited by the inability of conventional linkage analysis software to compute, in reasonable time, multipoint LOD scores for pedigrees with inbreeding loops. We have developed a new algorithm for rapid multipoint likelihood calculations in small pedigrees, including those with inbreeding loops. The running time of the algorithm grows, at most, linearly with the number of loci considered simultaneously. The running time is not sensitive to the presence of inbreeding loops, missing genotype information, and highly polymorphic loci. We have incorporated this algorithm into a software package, MAPMAKER/HOMOZ, that allows very rapid multipoint mapping of disease genes in nuclear families, including homozygosity mapping. Multipoint analysis with dozens of markers can be carried out in minutes on a personal workstation. 23 refs., 4 figs., 1 tab.

  13. High-resolution wave number spectrum using multi-point measurements in space - the Multi-point Signal Resonator (MSR) technique

    NASA Astrophysics Data System (ADS)

    Narita, Y.; Glassmeier, K.-H.; Motschmann, U.

    2011-02-01

    A new analysis method is presented that provides a high-resolution power spectrum in a broad wave number domain based on multi-point measurements. The analysis technique is referred to as the Multi-point Signal Resonator (MSR) and it benefits from Capon's minimum variance method for obtaining the proper power spectral density of the signal as well as the MUSIC algorithm (Multiple Signal Classification) for considerably reducing the noise part in the spectrum. The mathematical foundation of the analysis method is presented and it is applied to synthetic data as well as Cluster observations of the interplanetary magnetic field. Using the MSR technique for Cluster data we find a wave in the solar wind propagating parallel to the mean magnetic field with relatively small amplitude, which is not identified by the Capon spectrum. The Cluster data analysis shows the potential of the MSR technique for studying waves and turbulence using multi-point measurements.

  14. Improved thermoelectric cooling based on the Thomson effect

    NASA Astrophysics Data System (ADS)

    Snyder, G. Jeffrey; Khanna, Raghav; Toberer, Eric S.; Heinz, Nicholas A.; Seifert, Wolfgang

    2016-05-01

    Traditional thermoelectric cooling relies on the Peltier effect which produces a temperature drop limited by the figure of merit, zT. This cooling limit is not required from classical thermodynamics but can be traced to problems of thermoelectric compatibility. Alternatively, if a thermoelectric cooler can be designed to achieve full thermoelectric compatibility, lower temperature can be achieved even if the zT is low. In such a device the Thomson effect plays an important role. We present the theoretical concept of a "Thomson cooler," for cryogenic cooling which is designed to maintain thermoelectric compatibility and we derive the requirements for the Seebeck coefficient.

  15. Cathode Ray Research Leading to J.J. Thomson's Discovery

    NASA Astrophysics Data System (ADS)

    Mulligan, Joseph

    1997-04-01

    This paper reviews the research on the properties and nature of cathode rays that led to the discovery of the electron by J. J. Thomson in the years 1897 - 1899. During the period from about 1870 to 1897 important research on cathode rays was carried out by William Crookes and Arthur Schuster in England, by Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Emil Wiechert and Walter Kaufman in Germany, and by Jean Perrin in France. This research was always tedious and often inexact because fast vacuum pumps and convenient vacuum gauges did not yet exist. Still a few of these earlier researchers narrowly missed beating J. J. Thomson to the discover of the electron.

  16. Program For Joule-Thomson Analysis Of Mixed Cryogens

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Lund, Alan

    1994-01-01

    JTMIX computer program predicts ideal and realistic properties of mixed gases at temperatures between 65 and 80 K. Performs Joule-Thomson analysis of any gaseous mixture of neon, nitrogen, various hydrocarbons, argon, oxygen, carbon monoxide, carbon dioxide, and hydrogen sulfide. When used in conjunction with DDMIX computer program of National Institute of Standards and Technology (NIST), JTMIX accurately predicts order-of-magnitude increases in Joule-Thomson cooling capacities occuring when various hydrocarbons added to nitrogen. Also predicts boiling temperature of nitrogen depressed from normal value to as low as 60 K upon addition of neon. Written in Turbo C.

  17. ENLIL Global Heliospheric Modeling as a Context For Multipoint Observations

    NASA Astrophysics Data System (ADS)

    Mays, M. Leila; Odstrcil, Dusan; Luhmann, Janet; Bain, Hazel; Li, Yan; Schwadron, Nathan; Gorby, Matt; Thompson, Barbara; Jian, Lan; Möstl, Christian; Rouillard, Alexis; Davies, Jackie; Temmer, Manuela; Rastaetter, Lutz; Taktakishvili, Aleksandre; MacNeice, Peter; Kuznetsova, Maria

    2016-04-01

    We present heliospheric simulation case studies using recent enhancements to WSA--ENLIL+Cone (version 2.8) at the Community Coordinated Modeling Center (CCMC). The global 3D MHD ENLIL model provides a time-dependent description of the background solar wind plasma and magnetic field using a sequence of WSA coronal model maps as input at the inner boundary of 21.5 Rs. A homogeneous, over-pressured hydrodynamic plasma cloud is launched through the inner boundary of the heliospheric computational domain and into the background solar wind. Multipoint observations help constrain simulations and this modeling system provides global context and arrival times of the solar wind streams and CMEs at Earth, planets, and spacecraft. Additionally, one can extract the magnetic topologies of observer-connected magnetic field lines and all plasma and shock properties along those field lines. ENLIL "likelihood/all-clear" forecasting maps provide expected intensity, timing/duration of events at locations throughout the heliosphere with "possible SEP affected areas" color-coded based on shock strength. ENLIL simulations are also useful to drive SEP models such as the Solar Energetic Particle Model (SEPMOD) (Luhmann et al. 2007, 2010) and Energetic Particle Radiation Environment Module (EPREM) (Schwadron et al., 2010). SEPMOD injects protons onto a sequence observer field lines at intensities dependent on the connected shock source strength which are then integrated at the observer to approximate the proton flux. EPREM couples with MHD models such as ENLIL and computes energetic particle distributions based on the focused transport equation along a Lagrangian grid of nodes that propagate out with the solar wind. Studies have shown that accurate descriptions of the heliosphere, and hence modeled CME arrival times and SEPs, are achieved by ENLIL only when the background solar wind is well-reproduced and CME parameters are accurate. It is essential to include all of the relevant CMEs and

  18. The Thomson deflectometer: A novel use of the Thomson spectrometer as a transient field and plasma diagnostic

    SciTech Connect

    Ter-Avetisyan, S.; Schnuerer, M.; Nickles, P. V.; Sokollik, T.; Risse, E.; Kalashnikov, M.; Sandner, W.; Priebe, G.

    2008-03-15

    Laser accelerated proton beams have been used for field characterization in expanding plasmas. The Thomson parabola spectrometer, as a charged particles analyzer, also allows precise measurement of the charged particles' trajectories. The proton's deflections by fast changing plasma fields can be measured with the new design of the Thomson parabola spectrometer and, therefore, it can be applied for proton deflectometry. It is shown that from resulting spectrograms the plasma field dynamics can be reconstructed with high temporal resolution. In a proof-of-principle experiment, a weakly relativistic plasma expansion is studied as an example.

  19. Joule-Thomson coefficient of ideal anyons within fractional exclusion statistics

    SciTech Connect

    Qin Fang; Chen Jisheng

    2011-02-15

    The analytical expressions of the Joule-Thomson coefficient for homogeneous and harmonically trapped three-dimensional ideal anyons which obey Haldane fractional exclusion statistics are derived. For an ideal Fermi gas, the Joule-Thomson coefficient is negative, which means that there is no maximum Joule-Thomson inversion temperature. With careful study, it is found that there exists a Joule-Thomson inversion temperature in the fractional exclusion statistics model. Furthermore, the relations between the Joule-Thomson inversion temperature and the statistical parameter g are investigated.

  20. Simulation of Soil Macropore Networks Using Multi-Point Geostatistics

    NASA Astrophysics Data System (ADS)

    Luo, L.; Lin, H.; Singha, K.

    2006-12-01

    Two-point correlation functions have been used to quantitatively evaluate the spatial variability of soil structure but cannot characterize its specific geometry. Multi-point (MP) geostatistics can be used to consider both spatial correlation and the specific shape of objects. The algorithm, SNESIM, developed by Strebelle (2002) was used to simulate complex geological patterns, reflecting different scales of variability and types of heterogeneity. Soil macropores, especially earthworm burrows and root channels, are critical to preferential flow and transport in soils. Accurate simulation of soil macropore network can allow us better simulate soil hydraulic properties and address scaling issues of structured soils. However, little work has been done to simulate soil macropore network using MP geostatistics. 3D soil macropore network of an agricultural soil in Pennsylvania, Hagerstown silt loam, was extracted from the spatially exhaustive data collected with Micro Computing Tomography. 3D training image was scanned by 3D template to obtain the 3D patterns. Permeability of the simulated macropore network was calculated using Lattice-Boltzmann method. SNESIM was able to simulate different types of macropores, the earthworm burrows and inter-aggregate pores. However, SNESIM requires that training images must have a stationary character, which may limit its ability to simulate soil macropore network. SNESIM is still very computationally consuming for the 3D structure simulation. While computationally expensive, MP geostatistics has great potential for simulating 3D soil macropore network, which is useful to understand and predict the hydraulic behavior of structured soils.

  1. Dynamic Loads Generation for Multi-Point Vibration Excitation Problems

    NASA Technical Reports Server (NTRS)

    Shen, Lawrence

    2011-01-01

    A random-force method has been developed to predict dynamic loads produced by rocket-engine random vibrations for new rocket-engine designs. The method develops random forces at multiple excitation points based on random vibration environments scaled from accelerometer data obtained during hot-fire tests of existing rocket engines. This random-force method applies random forces to the model and creates expected dynamic response in a manner that simulates the way the operating engine applies self-generated random vibration forces (random pressure acting on an area) with the resulting responses that we measure with accelerometers. This innovation includes the methodology (implementation sequence), the computer code, two methods to generate the random-force vibration spectra, and two methods to reduce some of the inherent conservatism in the dynamic loads. This methodology would be implemented to generate the random-force spectra at excitation nodes without requiring the use of artificial boundary conditions in a finite element model. More accurate random dynamic loads than those predicted by current industry methods can then be generated using the random force spectra. The scaling method used to develop the initial power spectral density (PSD) environments for deriving the random forces for the rocket engine case is based on the Barrett Criteria developed at Marshall Space Flight Center in 1963. This invention approach can be applied in the aerospace, automotive, and other industries to obtain reliable dynamic loads and responses from a finite element model for any structure subject to multipoint random vibration excitations.

  2. Multipoint observations of Ionospheric Alfvén Resonance

    NASA Astrophysics Data System (ADS)

    Baru, N. A.; Koloskov, A. V.; Yampolsky, Y. M.; Rakhmatulin, R. A.

    2016-09-01

    Among the processes that form properties of the geospace in the circumterrestrial plasma the electromagnetic resonances of the Earth, such as Schummann Resonance (SR) and Ionospheric Alfvén Resonance (IAR) are of great importance. IAR is more localized in space than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is continuously observable at any time of the day, IAR signals are registered mostly during the nighttime and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure of the natural electromagnetic noise at frequency range 0.1-40 Hz. In this work we studied an influence of the environment characteristics on IAR parameters by the means of multipoint observations. Annual data series recorded at Ukrainian Antarctic Station "Akademik Vernadsky", Low Frequency Observatory of the Institute of Radio Astronomy near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. We investigated the behaviour of IAR parameters, such as probability of resonance lines registration and frequency spacing Δ F, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere above all of the observation points and geomagnetic activity.

  3. Development of a Multi-Point Microwave Interferometry (MPMI) Method

    SciTech Connect

    Specht, Paul Elliott; Cooper, Marcia A.; Jilek, Brook Anton

    2015-09-01

    A multi-point microwave interferometer (MPMI) concept was developed for non-invasively tracking a shock, reaction, or detonation front in energetic media. Initially, a single-point, heterodyne microwave interferometry capability was established. The design, construction, and verification of the single-point interferometer provided a knowledge base for the creation of the MPMI concept. The MPMI concept uses an electro-optic (EO) crystal to impart a time-varying phase lag onto a laser at the microwave frequency. Polarization optics converts this phase lag into an amplitude modulation, which is analyzed in a heterodyne interfer- ometer to detect Doppler shifts in the microwave frequency. A version of the MPMI was constructed to experimentally measure the frequency of a microwave source through the EO modulation of a laser. The successful extraction of the microwave frequency proved the underlying physical concept of the MPMI design, and highlighted the challenges associated with the longer microwave wavelength. The frequency measurements made with the current equipment contained too much uncertainty for an accurate velocity measurement. Potential alterations to the current construction are presented to improve the quality of the measured signal and enable multiple accurate velocity measurements.

  4. Local multipoint distribution system (LDMS) versus free-space optical (FSO) networks

    NASA Astrophysics Data System (ADS)

    Willebrand, Heinz A.; Clark, Gerald R.; Willson, Bryan; Andreu von Euw, Christian G.; Roy, Joe; Mayhew, Laurel M.

    2001-11-01

    This paper compares two emerging broadband access methodologies, Free Space Optics (FSO) and Local Multipoint Distribution System (LMDS) and the atmospheric propagation characteristics of each when exposed to a dynamically changing channel. The comparison focuses on bandwidth, availability, and distance requirements for the new broadband market and how LMDS and FSO can be used to meet these requirements. Possible network topologies and their associated costs are examined. This comparison takes into account the total cost of deployment, including equipment costs, installation fees, access fees, and spectrum licensing fees. LMDS and FSO are compared on speed of deployment, scalability, aggregate bandwidth, and bandwidth per customer. Present and projected capabilities of each technology are considered for their suitability in different locations in the network, from the Wide Area Network (WAN), to the Metropolitan Area Network (MAN), all the way to Last Mile Access. There is a discussion on the relative performance of LMDS and FSO, focusing on the different factors that can affect link availability. Since network design is a large factor in assuring overall reliability, the flexibility of each technology with regard to network design is compared. LMDS and FSO are both line of sight, space-propagated technologies, and as such, they are both susceptible to path impediments and atmospheric attenuation, dispersion, scattering, and absorption. LMDS and FSO are affected very differently by different meteorological phenomena. Problematic atmospheric conditions are, specifically scintillation, rainfall, and fog, are examined. In addition to a discussion of these conditions, various techniques for minimizing atmospheric and environmental effects are investigated. The paper concludes with a summary of findings and recommendations for a number of broadband wireless applications.

  5. Mixed-Gas Sorption Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Petrick, S. Walter; Bard, Steven

    1991-01-01

    Proposed mixed-gas sorption Joule-Thomson refrigerator provides cooling down to temperature of 70 K. Includes only one stage and no mechanical compressor. Simpler, operates without vibrating, and consumes less power in producing same amount of cooling. Same sorption principle of operation applicable in compressor that chemisorbs oxygen or hydrogen from mixture with helium, neon, and/or other nonreactive gases.

  6. Nonlinear Compton scattering of ultrashort intense laser pulses

    SciTech Connect

    Seipt, D.; Kaempfer, B.

    2011-02-15

    The scattering of temporally shaped intense laser pulses off electrons is discussed by means of manifestly covariant quantum electrodynamics. We employ a framework based on Volkov states with a time-dependent laser envelope in light-cone coordinates within the Furry picture. An expression for the cross section is constructed unambiguously in respect of the pulse length. A broad distribution of scattered photons with a rich pattern of subpeaks like that obtained in Thomson scattering is found. These broad peaks may overlap at sufficiently high laser intensity, rendering inappropriate the notion of individual harmonics. The limit of monochromatic plane waves as well as the classical limit of Thomson scattering are discussed. As a main result, a scaling law is presented connecting the Thomson limit with the general result for arbitrary kinematics. In the overlapping regions of the spectral density, the classical and quantum calculations give different results, even in the Thomson limit. Thus, a phase-space region is identified where the differential photon distribution is strongly modified by quantum effects.

  7. Nonlinear Compton scattering of ultrashort intense laser pulses

    NASA Astrophysics Data System (ADS)

    Seipt, D.; Kämpfer, B.

    2011-02-01

    The scattering of temporally shaped intense laser pulses off electrons is discussed by means of manifestly covariant quantum electrodynamics. We employ a framework based on Volkov states with a time-dependent laser envelope in light-cone coordinates within the Furry picture. An expression for the cross section is constructed unambiguously in respect of the pulse length. A broad distribution of scattered photons with a rich pattern of subpeaks like that obtained in Thomson scattering is found. These broad peaks may overlap at sufficiently high laser intensity, rendering inappropriate the notion of individual harmonics. The limit of monochromatic plane waves as well as the classical limit of Thomson scattering are discussed. As a main result, a scaling law is presented connecting the Thomson limit with the general result for arbitrary kinematics. In the overlapping regions of the spectral density, the classical and quantum calculations give different results, even in the Thomson limit. Thus, a phase-space region is identified where the differential photon distribution is strongly modified by quantum effects.

  8. Isotopic imaging via nuclear resonance fluorescence with laser-based Thomson radiation

    DOEpatents

    Barty, Christopher P. J.; Hartemann, Frederic V.; McNabb, Dennis P.; Pruet, Jason A.

    2009-07-21

    The present invention utilizes novel laser-based, high-brightness, high-spatial-resolution, pencil-beam sources of spectrally pure hard x-ray and gamma-ray radiation to induce resonant scattering in specific nuclei, i.e., nuclear resonance fluorescence. By monitoring such fluorescence as a function of beam position, it is possible to image in either two dimensions or three dimensions, the position and concentration of individual isotopes in a specific material configuration. Such methods of the present invention material identification, spatial resolution of material location and ability to locate and identify materials shielded by other materials, such as, for example, behind a lead wall. The foundation of the present invention is the generation of quasimonochromatic high-energy x-ray (100's of keV) and gamma-ray (greater than about 1 MeV) radiation via the collision of intense laser pulses from relativistic electrons. Such a process as utilized herein, i.e., Thomson scattering or inverse-Compton scattering, produces beams having diameters from about 1 micron to about 100 microns of high-energy photons with a bandwidth of .DELTA.E/E of approximately 10E.sup.-3.

  9. Polaritonic pulse and coherent X- and gamma rays from Compton (Thomson) backscattering

    SciTech Connect

    Apostol, M.; Ganciu, M.

    2011-01-01

    The formation of polariton wave-packets created by high-intensity laser beams focused in plasmas is analyzed, and the velocity, energy, size, structure, stability, and electron content of such polaritonic pulses are characterized. It is shown that polaritonic pulses may transport trapped electrons with appreciable energies, provided the medium behaves as a rarefied classical plasma. The relativistic electron energy is related to the polariton group velocity, which is close to the velocity of light in this case. The plasma pulse is polarized, and the electron number in the pulse is estimated as being proportional to the square root of the laser intensity and the 3/2-power of the pulse size. It is shown that Compton (Thomson) backscattering by such polaritonic pulses of electrons may produce coherent X- and gamma rays, as a consequence of the quasirigidity of the electrons inside the polaritonic pulses and their relatively large number. The classical results of the Compton scattering are re-examined in this context, the energy of the scattered photons and their cross-section are analyzed, especially for backscattering, the great enhancement of the scattered flux of X- or gamma rays due to the coherence effect is highlighted and numerical estimates are given for some typical situations.

  10. Solar Cycle Variation and Multipoint Studies of ICME Properties

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    2005-01-01

    The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, Wind, ACE and Pioneer Venus in quadrature, multipoint, and solar cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the solar wind conditions associated with these structures are the most geoeffective of any solar wind phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient solar wind producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient solar wind, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the solar wind [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient solar wind and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.

  11. Low-delay center-bridged and distributed combining schemes for multipoint videoconferencing

    NASA Astrophysics Data System (ADS)

    Chen, Ting-Chung; Wang, Wen-deh

    1994-09-01

    Multipoint videoconferencing is a natural evolution of two-point videoconferencing and can increase its value to users. Currently, ITU-T's SG8 and SG15 are working on multipoint control related issues; ANSI's T1A1.5 is also working in this area. The video coding and related communication standards of the upcoming MPEG4 and H.26P will all include multipoint communication capability. This paper investigates transport structures and the associated combining schemes that can be used to support multipoint videoconferencing. Since low delay is a major issue for multipoint interactive communications, a distributed structure which renders the lowest delay with many other system advantages is especially investigated. We first analyze the insertion delay of a QCIF combiner bridge which have been proposing for multipoint videoconferencing. Partial input-output pipelining has been used to reduce the delay. To reduce the insertion delay caused by unevenly distributed inputs, a parallel parsing scheme is proposed. This parallel parsing scheme allows low complexity inputs not to be held up by high complexity inputs and can reduce insertion delay significantly. An efficient delay- reduction algorithm using intraslice coding was also cited in a previous proposal. As a comparison, we describe low delay pel-domain transcoding schemes which have similar delay performance with coded-domain combining but have much higher complexities. We also describe a recent proposal which eliminates most of the insertion delay but which require major changes to existing standards and encoder and decoder implementations. The performance of a distributed transport structure in providing multipoint video services is then investigated. Using the face that bandwidth usage is an important factor in estimating network complexity, it is shown that a distributed transport structure saves 40 to 62.5% bandwidth for a 4-point conferencing and also renders the shortest delay when compared with other center

  12. Cryogenic characterization of low-cost Joule-Thomson coolers

    NASA Astrophysics Data System (ADS)

    Guichard, Jerome; Cottereau, Alain; Chazot, Dominique

    2000-12-01

    This paper highlights two main achievements which were performed by AIR LIQUIDE during the last decade in the field of low cost Joule-Thomson coolers. On one hand, in order to comply with new geometrical requirements, AIR LIQUIDE is able to propose a flat cooler. This compact geometry is enabled by a new, cheap, type of heat exchanger. It offers a better resistance to external vibrations. On the other hand AIR LIQUIDE has developed, in the frame of a commercial program, a complete cryogenic cooling system, composed of a dual flow Joule-Thomson cooler, a pressurized gas capacity equipped with a manifold block and a pyrotechnic actuator, and the requested pipes and connectors. The dual flow is enabled by flexion of a washer made of shape memory alloy.

  13. Thomson Reuters to release Book Citation Index later this year

    NASA Astrophysics Data System (ADS)

    Aldred, Maxine

    2011-08-01

    Thomson Reuters will launch its new Book Citation Index later this year. Projected to include 25,000 volumes from major publishers and university presses in science, social science, and the humanities, the Book Citation Index will cover scholarly books (both series and nonseries) that present original research or literature reviews. The current effort regarding the science section is focused on books published from 2005 to the present. AGU has sent copies of its catalog for inclusion in the Book Citation Index, but the final selection will be made by Thomson Reuters, using its internal selection criteria, which may be found at http://wokinfo.com/wok/media/pdf/BKCI-SelectionEssay_web.pdf.

  14. Theoretical study on a Miniature Joule-Thomson & Bernoulli Cryocooler

    NASA Astrophysics Data System (ADS)

    Xiong, L. Y.; Kaiser, G.; Binneberg, A.

    2004-11-01

    In this paper, a microchannel-based cryocooler consisting of a compressor, a recuperator and a cold heat exchanger has been developed to study the feasibility of cryogenic cooling by the use of Joule-Thomson effect and Bernoulli effect. A set of governing equations including Bernoulli equations and energy equations are introduced and the performance of the cooler is calculated. The influences of some working conditions and structure parameters on the performance of coolers are discussed in details.

  15. Innovation as a social process: Elihu Thomson and the rise of General Electric, 1870-1900

    SciTech Connect

    Carlson, W.B.

    1992-01-01

    This book traces the development of the General Electric Corporation by following the career of inventor Elihu Thomson, who along with Thomas Edison and George Westinghouse, achieved recoginition for the rapid emergence of electric light and power in America. The author explores Thomson's development as an inventor and scientist. He goes on to examine how Thomson applied his innovation and scientific skills in the marketplace, tracks the development of the Thomson-Houston Company and subsequent merger with Edison into General Electric. Book review.

  16. Multipoint Multimedia Conferencing System with Group Awareness Support and Remote Management

    ERIC Educational Resources Information Center

    Osawa, Noritaka; Asai, Kikuo

    2008-01-01

    A multipoint, multimedia conferencing system called FocusShare is described that uses IPv6/IPv4 multicasting for real-time collaboration, enabling video, audio, and group awareness information to be shared. Multiple telepointers provide group awareness information and make it easy to share attention and intention. In addition to pointing with the…

  17. On stability of difference schemes for hyperbolic multipoint NBVP with Neumann conditions

    NASA Astrophysics Data System (ADS)

    Yildirim, Ozgur; Uzun, Meltem

    2016-08-01

    In this work, a multipoint nonlocal boundary value problem (NBVP) for hyperbolic equations with Neumann conditions is considered. Third and fourth order of accuracy stable difference schemes for solving this problem are presented. Efficiency of these schemes are tested via MATLAB implementation.

  18. Multipoint alignment monitoring with amorphous silicon position detectors in a complex light path

    NASA Astrophysics Data System (ADS)

    Alberdi, J.; Arce, P.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Molinero, A.; Navarrete, J.; Oller, J. C.; Yuste, C.; Calderón, A.; Gómez, G.; González-Sánchez, F. J.; Martínez-Rivero, C.; Matorras, F.; Rodrigo, T.; Ruiz-Árbol, P.; Sobrón, M.; Vila, I.; Virto, A. L.

    2010-12-01

    This document presents an application of the new generation of amorphous silicon position detecting (ASPD) sensors to multipoint alignment. Twelve units are monitored along a 20 m long laser beam, where the light path is deflected by 90° using a pentaprism.

  19. Complete multipoint sib-pair analysis of qualitative and quantitative traits

    SciTech Connect

    Kruglyak, L.; Lander, E.S.

    1995-08-01

    Sib-pair analysis is an increasingly important tool for genetic dissection of complex traits. Current methods for sib-pair analysis are primarily based on studying individual genetic markers one at a time and thus fail to use the full inheritance information provided by multipoint linkage analysis. In this paper, we describe how to extract the complete multipoint inheritance information for each sib pair. We then describe methods that use this information to map loci affecting traits, thereby providing a unified approach to both qualitative and quantitative traits. Specifically, complete multipoint approaches are presented for (1) exclusion mapping of qualitative traits; (2) maximum-likelihood mapping of qualitative traits; (3) information-content mapping, showing the extent to which all inheritance information has been extracted at each location in the genome; and (4) quantitative-trait mapping, by two parametric methods and one nonparametric method. In addition, we explore the effects of marker density, marker polymorphism, and availability of parents on the information content of a study. We have implemented the analysis methods in a new computer package, MAPMAKER/SIBS. With this computer package, complete multipoint analysis with dozens of markers in hundreds of sib pairs can be carried out in minutes. 25 refs., 8 figs.

  20. The multipoint de la Vallee-Poussin problem for a convolution operator

    SciTech Connect

    Napalkov, Valentin V; Nuyatov, Andrey A

    2012-02-28

    Conditions are discovered which ensure that the space of entire functions can be represented as the sum of an ideal in the space of entire functions and the kernel of a convolution operator. In this way conditions for the multipoint de la Vallee-Poussin problem to have a solution are found. Bibliography: 14 titles.

  1. Multi-Point E-Conferencing with Initial Teacher Training Students in England: Pitfalls and Potential

    ERIC Educational Resources Information Center

    Pratt, Nick

    2008-01-01

    This article reports on attempts to initiate multi-point e-conferencing between English teacher education students on school placements, their host teachers and their university tutors. A sociocultural perspective is adopted in analysing the project, using the metaphor of a "professional knowledge landscape" [Clandinin, D. J., & Connelly, F. M.…

  2. Localization of the Krabbe disease gene (GALC) on chromosome 14 by multipoint linkage analysis

    SciTech Connect

    Oehlmann, R.; Wenger, D.A.; Knowlton, R.G. ); Zlotogora, J. )

    1993-12-01

    The gene responsible for Krabbe disease, an autosomal recessive disorder caused by deficiency of galactocerebrosidase (GALC), was localized by multipoint linkage analysis on chromosome 14. Eight mapped dinucleotide repeat polymorphisms were tested for linkage to GALC. Two-point linkage analysis demonstrated close linkage of GALC and D14S48, with [cflx [Zeta

  3. Multipoint laser Doppler vibrometry using holographic optical elements and a CMOS digital camera.

    PubMed

    Connelly, Michael J; Szecówka, Przemyslaw M; Jallapuram, Raghavendra; Martin, Suzanne; Toal, Vincent; Whelan, Maurice P

    2008-02-15

    A laser Doppler vibrometer (LDV) is described in which holographic optical elements are used to provide the interferometer reference and object illumination beams. A complementary metal-oxide semiconductor camera, incorporating a digital signal processor, is used to carry out real-time signal processing of the interferometer output to allow multipoint LDV to be implemented.

  4. Characterization of Laser-Driven Electron Beams for Thomson X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Shah, Rahul; Korbiak, Katherine; Valenzuela, Anthony; Banerjee, Sudeep; Umstadter, Donald

    2002-11-01

    The relativistic nonlinear motions of a free electron resulting from extreme intensity light fields results in harmonic generation, referred to as nonlinear Thomson scattering. Up to the 30th harmonic has been observed experimentally, and the role of energetic electrons has been inferred from the narrow angular spread of the scattered light[1]. Both experiment and theory lead us to the conclusion that the electron beam emittance, flux, and energy are critical factors. Here we report on recent studies to accurately characterize and improve the laser produced electron beam. The relationship of the gas delivery conditions is first investigated by interferometric characterization of gas output from both optimized supersonic nozzles[2] and typical nozzles utilized in past experiments at Michigan. These nozzles are then compared with respect to quality of electron beam generation. Electron beam emittance is measured using the pepperpot technique, and the charge is quantified non-perturbatively by utilizing an integrating current transformer. Aluminum and mylar filters allow us to examine emittance and flux for various components of the electron spectrum. These details of the scattering electron beam are critical considerations for the creation of an all-optical, short pulse, and high-spatial-coherence source of x-rays for time resolved diffraction and absorption studies. Work supported by the Chemical Sciences, Geosciences and Biosciences Division of the Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy and NSF Grants 0078581 and 0114336. [1] S. Banerjee, A. Valenzuela, R. Shah, A Maksimchuk, and D. Umstadter, Phys. Plasmas 9, 2392 (2002). [2] S. Semushin and V. Malka, Rev. of Sci. Inst. 72, 2961 (2001).

  5. 78 FR 8587 - Thomson Reuters, Finance Operations & Technology Division, Including On-Site Leased Workers From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ... was published in the Federal Register on August 16, 2012 (77 FR 49459). At the request of the State... Employment and Training Administration Thomson Reuters, Finance Operations & Technology Division, Including... Worker Adjustment Assistance on August 2, 2012, applicable to workers of Thomson Reuters,...

  6. The Kelvin-Thomson Atom. Part 2: The Many-Electron Atoms

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1977-01-01

    Presents part two of a two-part article describing the Kelvin-Thomson atom. This part discusses the arrangement of electrons within the atom and examines some of the properties predicted for elements in the Kelvin-Thomson model. (SL)

  7. Multiple Low Energy Long Bone Fractures in the Setting of Rothmund-Thomson Syndrome

    PubMed Central

    Beckmann, Nicholas

    2015-01-01

    Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis characterized by a poikilodermatous rash starting in infancy as well as various skeletal anomalies, juvenile cataracts, and predisposition to certain cancers. Although Rothmund-Thomson syndrome is associated with diminished bone mineral density in addition to multiple skeletal abnormalities, there are few reports of the association with stress fractures or pathologic fractures in low energy trauma or delayed healing of fractures. Presented is a case of a young adult male with Rothmund-Thomson syndrome presenting with multiple episodes of long bone fractures caused by low energy trauma with one of the fractures exhibiting significantly delayed healing. The patient was also found to have an asymptomatic stress fracture of the lower extremity, another finding of Rothmund-Thomson syndrome rarely reported in the literature. A thorough review of the literature and comprehensive presentation of Rothmund-Thomson syndrome is provided in conjunction with our case. PMID:26617641

  8. Interferometric Rayleigh Scattering Measurement System

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Danehy, Paul M. (Inventor); Lee, Joseph W. (Inventor)

    2008-01-01

    A method and apparatus for performing simultaneous multi-point measurements of multiple velocity components in a gas flow is described. Pulses of laser light are directed to a measurement region of unseeded gas to produce Rayleigh or Mie scattered light in a plurality of directions. The Rayleigh or Mie scattered light is collected from multiple directions and combined in a single collimated light beam. The Rayleigh or Mie scattered light is then mixed together with a reference laser light before it is passed through a single planar Fabry-Perot interferometer for spectral analysis. At the output of the interferometer, a high-sensitivity CCD camera images the interference fringe pattern. This pattern contains the spectral and spatial information from both the Rayleigh scattered light and the reference laser light. Interferogram processing software extracts and analyzes spectral profiles to determine the velocity components of the gas flow at multiple points in the measurement region. The Rayleigh light rejected by the interferometer is recirculated to increase the accuracy and the applicability of the method for measurements at high temperatures without requiring an increase in the laser energy.

  9. Non-coherent continuum scattering as a line polarization mechanism

    SciTech Connect

    Del Pino Alemán, T.; Manso Sainz, R.; Trujillo Bueno, J. E-mail: rsainz@iac.es

    2014-03-20

    Line scattering polarization can be strongly affected by Rayleigh scattering at neutral hydrogen and Thomson scattering at free electrons. Often a depolarization of the continuum results, but the Doppler redistribution produced by the continuum scatterers, which are light (hence, fast), induces more complex interactions between the polarization in spectral lines and in the continuum. Here we formulate and solve the radiative transfer problem of scattering line polarization with non-coherent continuum scattering consistently. The problem is formulated within the spherical tensor representation of atomic and light polarization. The numerical method of solution is a generalization of the Accelerated Lambda Iteration that is applied to both the atomic system and the radiation field. We show that the redistribution of the spectral line radiation due to the non-coherence of the continuum scattering may modify the shape of the emergent fractional linear polarization patterns significantly, even yielding polarization signals above the continuum level in intrinsically unpolarizable lines.

  10. Cytogenetic analysis in Rothmund-Thomson syndrome with osteosarcoma

    SciTech Connect

    Amar, M.; Sutphen, R.; Kousseff, B.G.

    1994-09-01

    Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive condition of poikiloderma, erythema, depigmentation, hyperpigmentation, musculoskeletal abnormalities and abnormalities of hair, teeth and nails. Osteogenic sacoma has been reported in 8 patients. Abnormal chromosome studies have been reported in only two patients. Chromosome analysis of tumor or bone marrow has not been reported. We performed cytogenetic studies on a patient with Rothmund-Thomson syndrome and osteogenic sarcoma. Analysis of peripheral lymphocytes revealed 46, XX karyotype by GTW banding. Both spontaneous and chemically-induced chromosome breakage (0.35 and 0.8 breaks/cell) were increased but not significantly different from the age-matched control levels (0.05 and 0.25 breaks/cell). Analysis of mitogen-stimulated bone marrow by Giemsa banding showed slightly increased aneuploidy (20% of cells with random loss of 1 to 5 chromosomes each) and non-specific chromatid despiralization. All 34 cells analyzed from the tumor had normal diploid karyotype, 46.XX. Five of 40 cells derived from skin of the amputated right leg were hyperdiploid with karyotype 47, XX, +7. Skin from the right forearm showed normal karyotype, 46,XX. These results suggest that RTS is associated with chromosomal rearrangement causing acquired somatic mosaicism, including trisomy 7 anomalies. These abnormalities may aid in the diagnosis of RTS and provide clues to the location of the causative gene(s).

  11. Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Nyland, Ted W.; Saiyed, Naseem H.

    1992-01-01

    Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

  12. Theoretical considerations for X-ray phase contrast mammography by Thomson source

    NASA Astrophysics Data System (ADS)

    Cedola, A.; Bukreeva, I.; Lagomarsino, S.; Petrillo, V.; Maroli, C.

    2009-09-01

    The advent, in the near future, of compact X-ray sources like Thomson Back-Scattering (TBS) will allow the clinical application of advanced X-ray imaging techniques, such as phase contrast, with higher sensitivity and lower impact in terms of dose delivery. In this work, we theoretically investigated the possibility of using such sources for phase contrast imaging of micro-calcifications included in a breast tissue. In our study we analyzed the phase and amplitude distribution of the TBS source and we showed that this source can be used for phase contrast imaging since the source coherence at the sample position is sufficiently high for achieving good contrast and micrometer spatial resolution. Indeed the spatial coherence of a TBS source is closer to that of a synchrotron radiation source, and much better than that of a laboratory source. Moreover, we showed the advantages of phase imaging with respect to standard absorption imaging, in the specific case of micro-calcifications detection.

  13. Preliminary results of equation of state measurements using imaging x-ray Thomson spectrometer

    NASA Astrophysics Data System (ADS)

    Belancourt, Patrick; Theobald, Wolfgang; Keiter, Paul; Collins, Timothy; Bonino, Mark; Kozlowski, Pawel; Drake, Paul; University of Michigan Team; LaboratoryLaser Energetics Team; University of Oxford Team

    2014-10-01

    Understanding the equation of state of materials under shocked conditions is important for laboratory astrophysics and high-energy-density physics experiments. The goal of the experiments discussed here is to create a platform for equation of state measurements in shocked foams on Omega EP. The target of interest for these experiments is shocked carbonized resorcinol formaldehyde foam with an initial density of 0.34 g/cc. Lasers irradiate an ablator, driving a shock into the foam. Plasma conditions ahead of the shock, at the shock and behind the shock are diagnosed using the imaging x-ray Thomson spectrometer (IXTS). The IXTS is capable of spectrally resolving the scattered x-ray beam while imaging in one spatial dimension. Preliminary results from these experiments will be shown. This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840, and the National Laser User Facility Program, Grant Number DE-NA0000850, and through the Laboratory for Laser Energetics, University of Rochester by the NNSA/OICF under Cooperative Agreement No. DE-FC52-08NA28302.

  14. Equation-of-State Measurements of Resorcinol Formaldehyde Foam Using Imaging X-Ray Thomson Spectrometer

    NASA Astrophysics Data System (ADS)

    Belancourt, Patrick; Theobald, W.; Keiter, P. A.; Collins, T. J. B.; Bonino, M. J.; Kozlowski, P.; Drake, R. P.

    2015-11-01

    Understanding the equation of state of materials under shocked conditions is important for laboratory astrophysics and high-energy-density physics experiments. This talk will focus on experiments dedicated to developing a platform for measuring the equation of state of shocked foams on OMEGA EP. The foam used in the development of this platform is resorcinol formaldehyde foam with an initial density of 0.34 g/cc. One OMEGA EP beam drives a shock into the foam, while the remaining three beams irradiate a nickel foil to create the x-ray backlighter. The primary diagnostic for this platform, the imaging x-ray Thomson spectrometer (IXTS), spectrally resolves the scattered x-ray beam while imaging in one spatial dimension. The IXTS is ideally suited to measure plasma conditions upstream, downstream and at the shock front in the foam. Preliminary results from these experiments will be shown. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas DE-NA0001840, and by the National Laser User Facility Program DE-NA0000850.

  15. A Robust Distributed Multipoint Fiber Optic Gas Sensor System Based on AGC Amplifier Structure.

    PubMed

    Zhu, Cunguang; Wang, Rende; Tao, Xuechen; Wang, Guangwei; Wang, Pengpeng

    2016-01-01

    A harsh environment-oriented distributed multipoint fiber optic gas sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the distributed multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process. PMID:27483267

  16. A Robust Distributed Multipoint Fiber Optic Gas Sensor System Based on AGC Amplifier Structure

    PubMed Central

    Zhu, Cunguang; Wang, Rende; Tao, Xuechen; Wang, Guangwei; Wang, Pengpeng

    2016-01-01

    A harsh environment-oriented distributed multipoint fiber optic gas sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the distributed multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process. PMID:27483267

  17. Maximum a posteriori estimation of spectral reflectance from color image and multipoint spectral measurements.

    PubMed

    Murakami, Yuri; Ietomi, Kunihiko; Yamaguchi, Masahiro; Ohyama, Nagaaki

    2007-10-01

    Accurate color image reproduction under arbitrary illumination can be realized if the spectral reflectance functions in a scene are obtained. Although multispectral imaging is one of the promising methods to obtain the reflectance of a scene, it is expected to reduce the number of color channels without significant loss of accuracy. This paper presents what we believe to be a new method for estimating spectral reflectance functions from color image and multipoint spectral measurements based on maximum a posteriori (MAP) estimation. Multipoint spectral measurements are utilized as auxiliary information to improve the accuracy of spectral reflectance estimated from image data. Through simulations, it is confirmed that the proposed method improves the estimation accuracy, particularly when a scene includes subjects that belong to various categories.

  18. The use of multipoint monitoring as a tool for commissioning buildings for IAQ

    SciTech Connect

    Bearg, D.W.

    1999-07-01

    One basic goal of the commissioning process is to make sure that the HVAC system is functioning as intended. In particular, it is intended that the HVAC system not only provide adequate ventilation for the building occupants but also achieve adequate pressurization of the occupied spaces to prevent the infiltration of unconditioned air. One technique for evaluating the performance of the HVAC system in these areas is to use continual, multipoint monitoring of carbon dioxide, carbon monoxide, and dew point at selected locations in the building and the HVAC system. Specific examples of all of these performance evaluations are presented and discussed in this paper. In addition, these ongoing evaluations of system performance can not only identify the presence of problems but can also evaluate the effectiveness of mitigation efforts to correct and eliminate these problems. The use of continual, multipoint monitoring of these parameters, therefore, can yield improved indoor air quality (IAQ) in buildings from initial occupancy throughout their useful life.

  19. Role of the Symmetry of Multipoint Hydrogen Bonding on Chelate Cooperativity in Supramolecular Macrocyclization Processes.

    PubMed

    Montoro-García, Carlos; Camacho-García, Jorge; López-Pérez, Ana M; Mayoral, María J; Bilbao, Nerea; González-Rodríguez, David

    2016-01-01

    Herein, we analyze the intrinsic chelate effect that multipoint H-bonding patterns exert on the overall energy of dinucleoside cyclic systems. Our results indicate that the chelate effect is regulated by the symmetry of the H-bonding pattern, and that the effective molarity is reduced by about three orders of magnitude when going from the unsymmetric ADD-DAA or DDA-AAD patterns to the symmetric DAD-ADA pattern.

  20. Multi-point quasi-rational approximants for the modified Bessel function I1(x)

    NASA Astrophysics Data System (ADS)

    Martin, P.; Olivares, J.; Cortés-Vega, L.; Sotomayor, A.

    2016-08-01

    Approximants for the modified Bessel function I1(x) has been found using the multi-point quasi-rational technique. The approximations here determined has good accuracy for any positive value of the variable, and it seems to be adequate for most of the works where this function are used. Furthermore, the approximants are simple to calculate numerically in a direct way or using any usual MAPLE or MATLAB software.

  1. Nd:GGG disk laser with multipoint spatially periodic optical pumping

    NASA Astrophysics Data System (ADS)

    Guryev, D. A.; Nikolaev, D. A.; Tsvetkov, V. B.

    2016-04-01

    The results of the study of the output laser beam spatial characteristics of the Nd:Gd3Ga5O12 (Nd:GGG) disk laser with multipoint spatially periodic diode-pumping are presented. The presence of the optical coupling between the TEM00 lasing channels is demonstrated. The phase-locking of channels was realized due to partial overlapping of laser beams inside the pumped areas of the active element disk.

  2. High-frequency gyrotron scattering diagnostic for instability studies on TARA

    SciTech Connect

    Woskoboinikow, P.; Cohn, D.R.; Gerver, M.; Mulligan, W.J.; Post, R.S.; Temkin, R.J.; Trulsen, J.

    1985-05-01

    A 1- to 10-kW,>30-ms pulsed, narrow linewidth (<1 MHz), 137-GHz gyrotron is being fabricated for collective Thomson scattering plasma diagnostics on the TARA tandem mirror experiment. The drift cyclotron loss cone, the axial loss cone, harmonics of these instabilities, and the ion two stream instability in the TARA plugs will be studied with this diagnostic.

  3. Multipoint Measurements and Global Simulations of the June 23, 2015 Geomagnetic Storm

    NASA Astrophysics Data System (ADS)

    Buzulukova, Natalia; Fok, Mei-Ching; Moore, Thomas E.; Glocer, Alex; Dorelli, John; Sibeck, David; Angelopoulos, Vassilis; Valek, Phil; McComas, David

    2016-04-01

    On 22-23 June 2015 a severe geomagnetic storm occurred with Dst minimum of approximately -200nT. During this extreme event, multipoint observations of magnetospheric dynamics were obtained by a fleet of Geospace spacecraft including MMS, TWINS, Van-Allen Probes and THEMIS. Extensive data coverage allows us to examine the responses of the ring current, radiation belts, ion composition and wave activity during this unusual event, both for the main phase of the storm as well as for the recovery phase. We present results of analysis of satellite data and simulation from a global coupled MHD-ring current model-radiation belt model (BATSRUS-CIMI) to connect multipoint observations from different parts of the magnetosphere. The output of virtual s/c in the global model is calculated and compared with the observations. The analysis helps to identify different magnetospheric domains from multipoint measurements and various magnetospheric boundary motions. We find the model is able to capture the global structure of the magnetosphere. We also explore how the initial disturbance from the solar wind propagates through the magnetosphere causing energization of plasma in the inner magnetosphere and producing severe geomagnetic activity.

  4. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    SciTech Connect

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; Doeppner, T.; Meyerhofer, D. D.; Murphy, C. D.; Sangster, T. C.; Vorberger, J.

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  5. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    DOE PAGESBeta

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; et al

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  6. Joule-Thomson Cooling Due to CO2 Injection into Natural GasReservoirs

    SciTech Connect

    Oldenburg, Curtis M.

    2006-04-21

    Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling that accompanies the expansion of a real gas. If Joule-Thomson cooling were extreme, injectivity and formation permeability could be altered by the freezing of residual water,formation of hydrates, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. For verification of EOS7C, the classic Joule-Thomson expansion experiment is modeled for pure CO2 resulting in Joule-Thomson coefficients in agreement with standard references to within 5-7 percent. For demonstration purposes, CO2 injection at constant pressure and with a large pressure drop ({approx}50 bars) is presented in order to show that cooling by more than 20 C can occur by this effect. Two more-realistic constant-rate injection cases show that for typical systems in the Sacramento Valley, California, the Joule-Thomson cooling effect is minimal. This simulation study shows that for constant-rate injections into high-permeability reservoirs, the Joule-Thomson cooling effect is not expected to create significant problems for CSEGR.

  7. Crystalline order on a sphere and the generalized Thomson problem.

    PubMed

    Bowick, M; Cacciuto, A; Nelson, D R; Travesset, A

    2002-10-28

    We attack the generalized Thomson problem, i.e., determining the ground state energy and configuration of many particles interacting via an arbitrary repulsive pairwise potential on a sphere via a continuum mapping onto a universal long range interaction between angular disclination defects parametrized by the elastic (Young) modulus Y of the underlying lattice and the core energy E(core) of an isolated disclination. Predictions from the continuum theory for the ground state energy agree with numerical simulations of long range power law interactions of the form 1/r(gamma) (0

  8. Thomson parabola spectrometry for gold laser-generated plasmas

    SciTech Connect

    Torrisi, L.; Cutroneo, M.; Ando, L.; Ullschmied, J.

    2013-02-15

    The plasma generated from thin gold films irradiated in high vacuum at high intensity ({approx}10{sup 15} W/cm{sup 2}) laser shot is characterized in terms of ion generation through time-of-flight techniques and Thomson parabola spectrometry. Gold ions and protons, accelerated in forward direction by the electric field developed in non-equilibrium plasma, have been investigated. Measurements, performed at PALS laboratory, give information about the gold charge states distributions, the ion energy distributions and the proton acceleration driven as a function of film thickness, laser parameters, and angular emission. The ion diagnostics of produced plasma in forward direction permits to understand some mechanisms developed during its expansion kinetics. The role of the focal position of a laser beam with respect to the target surface, plasma properties, and the possibility to accelerate protons up to energies above 3 MeV has been presented and discussed.

  9. Unveiling the physics of the Thomson jumping ring

    NASA Astrophysics Data System (ADS)

    Ladera, Celso L.; Donoso, Guillermo

    2015-04-01

    We present a new theoretical model and validating experiments that unveil the rich physics behind the flight of the conductive ring in the Thomson experiment—physics that is hard to see because of the rapid motion. The electrodynamics of the flying ring exhibits interesting features, e.g., varying mutual inductance between the ring and the electromagnet. The dependences of the ring electrodynamics upon time and position as the ring travels upward are conveniently separated and determined to obtain a comprehensive view of the ring motion. We introduce a low-cost jumping ring setup that incorporates pickup coils connected in opposition, allowing us to scrutinize the ring electrodynamics and confirm our theoretical model with good accuracy. This work is within the reach of senior students of science or engineering, and it can be implemented either as a teaching laboratory experiment or as an open-ended project.

  10. Fluctuations and Gibbs-Thomson Law - the Simple Physics.

    SciTech Connect

    Chernov, A A; De Yoreo, J J; Rashkovich, L N

    2006-09-15

    Crystals of slightly soluble materials should be subject of relatively weak attachment/detachment fluctuations on their faces so that steps on that faces have low kink density. These steps are parallel to the most close packed lattice rows and form polygons on a crystal surface. The process responsible for implementation of the classical Gibbs-Thomson law (GTL) for the polygonal step (in two dimensions, 2D) is kink exchange between the step corners. For the 3D crystallites, this mechanism includes step exchange. If these mechanisms do not operate because of slow fluctuations the GTL is not applicable. Physics of these processes and conditions for the GTL applicability are discussed on a simple qualitative level.

  11. Antibacterial alkaloids from Artabotrys crassifolius Hook.f. & Thomson.

    PubMed

    Tan, Kok Kwan; Khoo, Teng Jing; Rajagopal, Mogana; Wiart, Christophe

    2015-01-01

    Chloroform extract of bark of Artabotrys crassifolius Hook.f. & Thomson exhibited antibacterial activities against both American Type Culture Collection and clinical bacterial strains in vitro with zones of inhibition ranging from 7 to 14 mm. Further analysis of this extract yielded artabotrine, liridine, lysicamine and atherospermidine. Artabotrine displayed a broad array of antibacterial activity mostly against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 1.25 μg/mL to 5 μg/mL. Of note, artabotrine, liridine and lysicamine are bactericidal against Gram-negative extended-spectrum beta-lactamase-producing Klebsiella with MIC values equal 2.5, 2.5 and 10 μg/mL, respectively, and minimum bactericidal concentrations values equal to 2.5, 5 and 20 μg/mL.

  12. Elevated-pressure mixed-coolants Joule Thomson cryocooling

    NASA Astrophysics Data System (ADS)

    Maytal, B.-Z.; Nellis, G. F.; Klein, S. A.; Pfotenhauer, J. M.

    2006-01-01

    This paper explores the potential of mixed coolants at elevated pressures for Joule-Thomson cryocooling. A numerical model of a Joule-Thomson cryocooler is developed that is capable of simulating operation with mixtures of up to 9 components consisting of hydrocarbons, non-flammable halogenated refrigerants, and inert gases. The numerical model is integrated with a genetic optimization algorithm, which has a high capability for convergence in an environment of discontinuities, constraints and local optima. The genetic optimization algorithm is used to select the optimal mixture compositions that separately maximizes following two objective functions at each elevated pressure for 80, 90 and 95 K cryocooling: the molar specific cooling capacity (the highest attainable is 3200 J/mol) and the produced cooling capacity per thermal conductance which is a measure of the compactness of the recuperator. The optimized cooling capacity for a non-flammable halogenated refrigerant mixture is smaller than for a hydrocarbon mixture; however, the cooling capacity of the two types of mixtures approach one another as pressure becomes higher. The coefficient of performance, the required heat transfer area and the effect of the number of components in the mixture is investigated as a function of the pressure. It is shown that mixtures with more components provide a higher cooling capacity but require larger recuperative heat exchangers. Optimized mixtures for 90 K cryocooling have similar cooling capacity as those for 80 K. Optimized compactness for 80 K is about 50% higher than can be achieved by pure nitrogen. For 90 K, no mixture provides a more compact recuperator than can be achieved using pure argon. The results are discussed in the context of potential applications for closed and open cycle cryocoolers.

  13. Magnetized stimulated scattering in pulsar winds

    NASA Technical Reports Server (NTRS)

    Sincell, Mark W.; Krolik, Julian H.

    1992-01-01

    The effects of stimulated scattering on a collimated high brightness temperature beam of photons traversing a relativistically streaming magnetized plasma are studied. Under the assumption that the center of the photon beam is parallel to the bulk motion, we calculate the scattering rate as a function of the angular spread of the beam and the Lorentz factor gamma. Magnetization changes the photon recoil, without which stimulated scattering has no effect. It also introduces a strong dependence on frequency and polarization: if the photon frequency matches the electron cyclotron frequency, the scattering rate of photons polarized perpendicular to the magnetic field can be substantially enhanced relative to Thomson, and if the photon frequency is much less than the cyclotron frequency, the scattering is suppressed. Applying these calculations to pulsars, we find that stimulated scattering of the radio beam in the magnetized wind believed to exist outside the light cylinder can substantially alter the spectrum and polarization state of the radio signal. We suggest that the scattering rate is so high in some pulsars that the ability of the radio signal to penetrate the pulsar magnetosphere requires modification of either the conventional model of the magnetosphere or assumptions about the effects of stimulated scattering upon a beam.

  14. Comment on "Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping"

    NASA Astrophysics Data System (ADS)

    Terzić, Balša; Krafft, Geoffrey A.

    2016-09-01

    Rykovanov, Geddes, Schroeder, Esarey and Leemans [Phys. Rev. Accel. Beams 19, 030701 (2016), 10.1103/PhysRevAccelBeams.19.030701; hereafter RGSEL] have recently reported on the analytic derivation for the laser pulse frequency modulation (chirping) which controls spectrum broadening for high laser pulse intensities. We demonstrate here that their results are the same as the exact solutions reported in Terzić, Deitrick, Hofler and Krafft [Phys. Rev. Lett. 112, 074801 (2014), 10.1103/PhysRevLett.112.074801; hereafter TDHK]. While the two papers deal with circularly and linearly polarized laser pulses, respectively, the difference in expressions for the two is just the usual factor of 1 /2 present from going from circular to linear polarization. In addition, we note the authors used an approximation to the number of subsidiary peaks in the unchirped spectrum when a better solution is given in TDHK.

  15. Thomson, the right to life, and partial birth abortion or two MULES for Sister Sarah.

    PubMed

    Alward, P

    2002-04-01

    In this paper, I argue that Thomson's famous attempt to reconcile the fetus's putative right to life with robust abortion rights is not tenable. Given her view, whether or not an abortion violates the fetus's right to life depends on the abortion procedure utilised. And I argue that Thomson's view implies that any late term abortion that involves feticide is impermissible. In particular, this would rule out the partial birth abortion technique which has been so controversial of late.

  16. The network and transmission of based on the principle of laser multipoint communication

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Liu, Xianzhu; Jiang, Huilin; Hu, Yuan; Jiang, Lun

    2014-11-01

    Space laser communication is the perfectly choose to the earth integrated information backbone network in the future. This paper introduces the structure of the earth integrated information network that is a large capacity integrated high-speed broadband information network, a variety of communications platforms were densely interconnected together, such as the land, sea, air and deep air users or aircraft, the technologies of the intelligent high-speed processing, switching and routing were adopt. According to the principle of maximum effective comprehensive utilization of information resources, get accurately information, fast processing and efficient transmission through inter-satellite, satellite earth, sky and ground station and other links. Namely it will be a space-based, air-based and ground-based integrated information network. It will be started from the trends of laser communication. The current situation of laser multi-point communications were expounded, the transmission scheme of the dynamic multi-point between wireless laser communication n network has been carefully studied, a variety of laser communication network transmission schemes the corresponding characteristics and scope described in detail , described the optical multiplexer machine that based on the multiport form of communication is applied to relay backbone link; the optical multiplexer-based on the form of the segmentation receiver field of view is applied to small angle link, the optical multiplexer-based form of three concentric spheres structure is applied to short distances, motorized occasions, and the multi-point stitching structure based on the rotation paraboloid is applied to inter-satellite communications in detail. The multi-point laser communication terminal apparatus consist of the transmitting and receiving antenna, a relay optical system, the spectroscopic system, communication system and communication receiver transmitter system. The communication forms of optical

  17. On the Interconnection of Incompatible Solid Finite Element Meshes Using Multipoint Constraints

    NASA Technical Reports Server (NTRS)

    Fox, G. L.

    1985-01-01

    Incompatible meshes, i.e., meshes that physically must have a common boundary, but do not necessarily have coincident grid points, can arise in the course of a finite element analysis. For example, two substructures may have been developed at different times for different purposes and it becomes necessary to interconnect the two models. A technique that uses only multipoint constraints, i.e., MPC cards (or MPCS cards in substructuring), is presented. Since the method uses only MPC's, the procedure may apply at any stage in an analysis; no prior planning or special data is necessary.

  18. Development of a multi-point polarization-based vibration sensor.

    PubMed

    Linze, Nicolas; Tihon, Pierre; Verlinden, Olivier; Mégret, Patrice; Wuilpart, Marc

    2013-03-11

    In this paper we propose a novel kind of multi-point vibration sensor based on the polarization properties of light. Its principle relies on the combination of mechanical transducers with fiber Bragg gratings. When subject to vibrations, the mechanical transducers induce birefringence variations within the fiber and in turn modify the state of polarization, which appears as a power variation after going through a polarizer. The FBGs reflect light from different positions of the sensing fiber and provide wavelength multiplexing. We show that this sensor can provide the vibration frequencies in a quasi-distributed manner.

  19. Time- and media-saving testing and identification of microorganisms by multipoint inoculation on undivided agar plates.

    PubMed Central

    Burman, L G; Ostensson, R

    1978-01-01

    Motility and various biochemical activities of isolates of bacteria and yeasts were tested on undivided agar plates by using a simple, manually operated multipoint inoculation apparatus that allowed the analysis of 25 isolates per 9-cm-diameter petri plate. Fermentation of all 17 carbohydrates tested as well as 13 other biochemical activities commonly used for identification of bacteria were readily demonstrated by the multipoint inoculation plate method, and the results agreed very well with those of conventional tube tests. In addition to speedy inoculation and low cost of materials, the multipoint inoculation plate method offers several other advantages when compared with conventional tube tests or with some of the manufactured test kits currently available for recognizing members of the family Enterobacteriaceae. Images PMID:359588

  20. A study of optical scattering methods in laboratory plasma diagnosis

    NASA Technical Reports Server (NTRS)

    Phipps, C. R., Jr.

    1972-01-01

    Electron velocity distributions are deduced along axes parallel and perpendicular to the magnetic field in a pulsed, linear Penning discharge in hydrogen by means of a laser Thomson scattering experiment. Results obtained are numerical averages of many individual measurements made at specific space-time points in the plasma evolution. Because of the high resolution in k-space and the relatively low maximum electron density 2 x 10 to the 13th power/cu cm, special techniques were required to obtain measurable scattering signals. These techniques are discussed and experimental results are presented.

  1. Improving Control in a Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Borders, James; Pearson, David; Prina, Mauro

    2005-01-01

    A report discusses a modified design of a Joule-Thomson (JT) refrigerator under development to be incorporated into scientific instrumentation aboard a spacecraft. In most other JT refrigerators (including common household refrigerators), the temperature of the evaporator (the cold stage) is kept within a desired narrow range by turning a compressor on and off as needed. This mode of control is inadequate for the present refrigerator because a JT-refrigerator compressor performs poorly when the flow from its evaporator varies substantially, and this refrigerator is required to maintain adequate cooling power. The proposed design modifications include changes in the arrangement of heat exchangers, addition of a clamp that would afford a controlled heat leak from a warmer to a cooler stage to smooth out temperature fluctuations in the cooler stage, and incorporation of a proportional + integral + derivative (PID) control system that would regulate the heat leak to maintain the temperature of the evaporator within a desired narrow range while keeping the amount of liquid in the evaporator within a very narrow range in order to optimize the performance of the compressor. Novelty lies in combining the temperature- and cooling-power-regulating controls into a single control system.

  2. Rothmund-Thomson Syndrome: A 13-Year Follow-Up

    PubMed Central

    Guerrero-González, Guillermo Antonio; Martínez-Cabriales, Sylvia Aideé; Hernández-Juárez, Aideé Alejandra; de Jesús Lugo-Trampe, José; Espinoza-González, Nelly Alejandra; Gómez-Flores, Minerva; Ocampo-Candiani, Jorge

    2014-01-01

    Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive disorder presenting with poikiloderma and other clinical features, affecting the bones and eyes and, in type II RTS, presenting an increased risk for malignancy. With about 300 cases reported so far, we present a 13-year follow-up including clinical images, X-rays and genetic analysis. A 13-month-old female started with a facial rash with blisters on her cheeks and limbs at the age of 3 months along with congenital hypoplastic thumbs, frontal bossing and fine hair, eyebrows and eyelashes. The patient was lost to follow-up and returned 12 years later with palmoplantar hyperkeratotic lesions, short stature, disseminated poikiloderma and sparse scalp hair, with absence of eyelashes and eyebrows. Radiographic analysis showed radial ray defect, absence of the thumb and three wrist carpal bones, and reduced bone density. Gene sequencing for the RECQL4 helicase gene revealed a mutation on each allele. RTS is a rare disease, and in this patient we observed the evolution of her skin lesions and other clinical features, which were important for the classification of type II RTS. The next years will provide even more information on this rare disease. PMID:25120469

  3. Status report of the Thomson spectrometer for LILIA experiment

    NASA Astrophysics Data System (ADS)

    Maggiore, M.; Cirrone, G. A. P.; Romano, F.; Caruso, A.; Caruso, G.; Longhitano, A.; Messina, G.; Passarello, S.; Rizzo, D.; Salomone, S.; Zappalà, E.

    2013-06-01

    LILIA is an experiment of light ions acceleration trough laser interaction with thin metal targets to be done at the FLAME facility, which is now running in INFN-LNF of Frascati (Rome). In the framework of LILIA, the LNS is involved in the design and construction of a spectrometer based on the Thomson's configuration in order to diagnostic the ion ejection from the laser-generated plasma. The main goal is to realize a compact system which is both very practical and optimized with regard to the mass and energy resolution of particles obtained by laser-plasma interactions. The preliminary design has to be able to analyze and resolve beams of protons and ions up the total energy of 10 MeV. However, the technical choices adopted in this prototype have to be applied for the final device concerning a challenging spectrograph able to analyze beams of 150 MeVof total energy. The magnetic and the electric part have been built and these have been assembled. The vacuum and the high voltage test have been accomplished out and also the magnetic measurements. The results will be presented and discussed.

  4. Characterization of a thermoelectric/Joule-Thomson hybrid microcooler

    NASA Astrophysics Data System (ADS)

    Cao, H. S.; Vanapalli, S.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.

    2016-07-01

    Micromachined Joule-Thomson (JT) coolers are attractive for cooling small electronic devices. However, microcoolers operated with pure gases, such as nitrogen gas require high pressures of about 9 MPa to achieve reasonable cooling powers. Such high pressures severely add complexity to the development of compressors. To overcome this disadvantage, we combined a JT microcooler with a thermoelectric (TE) pre-cooler to deliver an equivalent cooling power with a lower pressure or, alternatively, a higher cooling power when operating with the same pressure. This hybrid microcooler was operated with nitrogen gas as the working fluid at a low pressure of 0.6 MPa. The cooling power of the microcooler at 101 K operating with a fixed high pressure of 8.8 MPa increased from 21 to 60 mW when the precooling temperature was reduced by the thermoelectric cooler from 295 to 250 K. These tests were simulated using a dynamic numerical model and the accuracy of the model was verified through the comparison between experimental and simulation results. Based on the model, we found the high pressure of the microcooler can be reduced from 8.8 to 5.5 MPa by lowering the precooling temperature from 295 to 250 K. Moreover, the effect of TE cooler position on the performance of the hybrid microcooler was evaluated through simulation analysis.

  5. Miniature Piezoelectric Compressor for Joule-Thomson Cryocoolers

    NASA Astrophysics Data System (ADS)

    Sobol, Sergey; Tzabar, Nir; Grossman, Gershon

    Joule-Thomson (JT) cryocoolers operate with a continuous flow of the working fluid that enters the cooler at a high pressure and leaves it at a lower pressure. Ideally, the temperature of the outgoing fluid equals the temperature of the entering fluid. JT cryocoolers that operate with pure refrigerants require high pressure of a few tens of MPa where the low pressure is usually around 0.1 MPa. Circulation of the working fluid in such cases requires high pressure ratio compressors that evidently have large dimensions. JT cryocoolers can operate with much lower pressure ratios by using mixed-refrigerants. Cooling from 300 K to about 80 K in a single stage cryocooler normally requires a pressure ratio of about 1:25. In the present research a miniature compressor driven by piezoelectric elements is developed in collaboration between Rafael and the Technion. This type of compressor has the advantage of improved long life compared to other mechanical compressors, very low vibrations, and silent operation. In the current case, the design goal of the intake and discharge pressures has been 0.1 and 2.5 MPa, respectively, with a flow rate of 0.06 g/s. The compressor has two compression stages; 1:5 and 5:25. Several configurations have been considered, fabricated, and tested. The performance of the last configuration approaches the desired specification and is presented in the current paper together with the design concept.

  6. Multi-point objective-oriented sequential sampling strategy for constrained robust design

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Zhang, Siliang; Chen, Wei

    2015-03-01

    Metamodelling techniques are widely used to approximate system responses of expensive simulation models. In association with the use of metamodels, objective-oriented sequential sampling methods have been demonstrated to be effective in balancing the need for searching an optimal solution versus reducing the metamodelling uncertainty. However, existing infilling criteria are developed for deterministic problems and restricted to one sampling point in one iteration. To exploit the use of multiple samples and identify the true robust solution in fewer iterations, a multi-point objective-oriented sequential sampling strategy is proposed for constrained robust design problems. In this article, earlier development of objective-oriented sequential sampling strategy for unconstrained robust design is first extended to constrained problems. Next, a double-loop multi-point sequential sampling strategy is developed. The proposed methods are validated using two mathematical examples followed by a highly nonlinear automotive crashworthiness design example. The results show that the proposed method can mitigate the effect of both metamodelling uncertainty and design uncertainty, and identify the robust design solution more efficiently than the single-point sequential sampling approach.

  7. Multipoint and multilevel injection technique of botulinum toxin A in facial aesthetics.

    PubMed

    Iozzo, Ivano; Tengattini, Vera; Antonucci, Valentina A

    2014-06-01

    Botulinum toxin represents one of the most frequently requested cosmetic procedures. We treated 223 patients with facial wrinkles using a new technique of injection of botulinum toxin A (BTA) called multipoint and multilevel injection technique (MMIT). The aim of MMIT was to relax the muscle and not paralyze it. Patient satisfaction was evaluated by Facial Line Treatment Satisfaction Questionnaire (FTSQ). Treatment with botulinum toxin determined a good response in all patients. Facial rhytids were completely resolved in case of young skin and well reduced in case of aged skin, leaving a natural aspect both in static and dynamic wrinkles. Patient mean overall satisfaction evaluated with FTSQ was 6.4 ± 1.1. In our experience, the use of botulin toxin by MMIT consents a better calibration of action with a soft and natural result. This can be achieved by distributing the BTA dose through various injection points for each area ("multipoint injections"). Furthermore, injections can be performed at different levels ("multilevel injections"). The level of injections regulates the potency of effect on the muscle: if the level is deep (intramuscular), the effect will be strong while if it is medium or superficial (subcutaneous and intradermal), the effect will be soft. This consents a fine calibration of action on muscle activity with a personal aesthetic result.

  8. Multi-Point Electric Field Observations in the High-Altitude Cusp Region

    NASA Astrophysics Data System (ADS)

    Laakso, H.; Escoubet, C.; Grard, R.; Masson, A.; Moullard, O.; Andre, M.; Eriksson, A. I.; Gustafsson, G.; Hull, A.; Mozer, F.; Lindqvist, P.; Pedersen, A.; Balogh, A.; Dunlop, M.; Fazakerley, A.; Taylor, M.

    2001-12-01

    In January-April 2001 the Cluster quartet crossed the cusp region twice per their 56 hours orbital period. These cusp encounters occurred at high altitudes, usually above 8 RE distance. Basically these encounters can be categorized into two groups. The first group consists of crossings where the satellites enter and exit the cusp at a rather constant altitude so that the satellites exit/enter the cusp through the entry layer, on the equatorial side of the cusp, and the plasma mantle, on the poleward side of the cusp. In the second group, the satellites' movement is quite parallel with respect to cusp orientation so that their altitude changes quickly with a rather constant latitude, and then the satellites enter/exit the cusp through the exterior cusp, in the magnetosheath just above the cusp. In this study we will investigate multi-point measurements with the Cluster electric field instrument (EFW) which let us study both plasma drift patterns and electron density variations (from the spacecraft potential data) within the cusp region. We also utilize simultaneous ion, electron, and magnetic field measurements that are important observations for our effort to interpret the EFW data. In particular we attempt to investigate both dynamical and structural aspects of the cusp, as with multi-point observations we have a chance to separate spatial and temporal features from the data.

  9. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lyon, Elliott; Kuang, Zheng; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2014-11-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion - a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed.

  10. Simultaneous multipoint acoustic emission sensing using fibre acoustic wave grating sensors with identical spectrum

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Ryul; Lee, Seung-Seok; Yoon, Dong-Jin

    2008-08-01

    This paper introduces the development of a simultaneous multipoint acoustic emission (AE) sensing system using a narrowband tuneable laser with high power and fibre acoustic wave grating sensors (FAWGSs). The demodulation technique is the same as that used in existing methods where the narrowband laser peak is tuned to one mid-reflection point in the main lobe of a fibre Bragg grating (FBG) spectrum. However, the sensor head is changed to an FAWGS for which a FBG is installed in a strain-free configuration so that it can detect AE waves in a structure not directly but in the form of a fibre-guided acoustic wave. Therefore since the structural strain cannot make the Bragg wavelength change, multiple FBGs with identical spectrum can be connected with multiple optical paths realized by equal light intensity dividers. The possible temperature difference between the multiple FAWGSs is passively resolved by using short FBGs which provide a wider operating temperature region. Consequently, we can resolve the problem that the FBG spectrum is easily deviated from the lasing wavelength because of the strain. In addition, the simultaneous multipoint sensing capability based on a single laser improves the cost-performance ratio of the optical system as well as reducing the structural inspection time, and enabling in situ health monitoring of real structures exposed to large and dynamic strains. The feasibility of the system is demonstrated in typical applications of in situ structural health monitoring based on AE techniques.

  11. A multi-point laser Doppler vibrometer with fiber-based configuration

    SciTech Connect

    Yang, C.; Guo, M.; Liu, H.; Yan, K.; Xu, Y. J.; Fu, Y.; Miao, H.

    2013-12-15

    Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration, it becomes more practical for dynamic structural evaluation in industrial areas.

  12. Micro-Hole Multi-Point Punching System Using Punch and Die Made by EDM

    NASA Astrophysics Data System (ADS)

    Broomfield, Mark; Mori, Toshihiko; Mikuriya, Teruaki; Tachibana, Kazushi

    In this research a multi-point micro punch and die system was developed. The process of electric discharge machining (EDM) was used to produce both the punch and die. The punches were machined from a 5 mm diameter tungsten and a 10 mm diameter tool steel round rods by wire electric discharge machining (WEDM), using a 200 µm diameter wire electrode. The die holes were made using the punch as the electrode. The EDM process of the holes was carried out on a newly developed desktop EDM machine. The punch and die placed on a micro-die set and then on a micro press were used to produce micro-holes using an automatic control system developed for this process. Experiments to produce 50 µm to 67 µm square micro-holes on 50 µm thick aluminum, 30 µm thick copper and 20 µm thick stainless steel foils were conducted. The capabilities of multi-point punching using the tungsten punch and a tool steel punch were examined and tungsten was chosen as the material of choice for making the punch tool. A scanning electron microscope confirmed that the holes produced are clean, and the sheared surfaces smooth. The punch tool showed no signs of deformation or cracks even after repeated punching.

  13. Visual processing of informative multipoint correlations arises primarily in V2.

    PubMed

    Yu, Yunguo; Schmid, Anita M; Victor, Jonathan D

    2015-04-27

    Using the visual system as a model, we recently showed that the efficient coding principle accounted for the allocation of computational resources in central sensory processing: when sampling an image is the main limitation, resources are devoted to compute the statistical features that are the most variable, and therefore the most informative (eLife 2014;3:e03722. DOI: 10.7554/eLife.03722 Hermundstad et al., 2014). Building on these results, we use single-unit recordings in the macaque monkey to determine where these computations--sensitivity to specific multipoint correlations--occur. We find that these computations take place in visual area V2, primarily in its supragranular layers. The demonstration that V2 neurons are sensitive to the multipoint correlations that are informative about natural images provides a common computational underpinning for diverse but well-recognized aspects of neural processing in V2, including its sensitivity to corners, junctions, illusory contours, figure/ground, and 'naturalness.'

  14. Multipoint oligogenic analysis of age-at-onset data with applications to Alzheimer disease pedigrees.

    PubMed Central

    Daw, E W; Heath, S C; Wijsman, E M

    1999-01-01

    It is usually difficult to localize genes that cause diseases with late ages at onset. These diseases frequently exhibit complex modes of inheritance, and only recent generations are available to be genotyped and phenotyped. In this situation, multipoint analysis using traditional exact linkage analysis methods, with many markers and full pedigree information, is a computationally intractable problem. Fortunately, Monte Carlo Markov chain sampling provides a tool to address this issue. By treating age at onset as a right-censored quantitative trait, we expand the methods used by Heath (1997) and illustrate them using an Alzheimer disease (AD) data set. This approach estimates the number, sizes, allele frequencies, and positions of quantitative trait loci (QTLs). In this simultaneous multipoint linkage and segregation analysis method, the QTLs are assumed to be diallelic and to interact additively. In the AD data set, we were able to localize correctly, quickly, and accurately two known genes, despite the existence of substantial genetic heterogeneity, thus demonstrating the great promise of these methods for the dissection of late-onset oligogenic diseases. PMID:10053019

  15. A multi-point laser Doppler vibrometer with fiber-based configuration.

    PubMed

    Yang, C; Guo, M; Liu, H; Yan, K; Xu, Y J; Miao, H; Fu, Y

    2013-12-01

    Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration, it becomes more practical for dynamic structural evaluation in industrial areas.

  16. Effects of environmental temperature on performance of the Joule-Thomson refrigerator

    NASA Astrophysics Data System (ADS)

    Hong, Yong-Ju; Kim, Hyobong; Park, Seong-Je

    2012-06-01

    Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. Typical performance factors of the Joule-Thomson refrigerator are cool-down time, temperature of the cold end, running time and gas consumption. Those depend on operating conditions such as the pressure of the gas, thermal environment and etc.. In this study, experimental study of a miniature Joule- Thomson refrigerator with the gas pressure up to 12 MPa were performed to investigate the effects of the thermal environment (-40 ~ 50 °C). In experiments, to obtain the information of cool-down time, gas consumption and etc., the temperature of the cold end, mass flow rate and pressure of the argon gas are simultaneously measured. The Joule-Thomson refrigerator in cold thermal environment has rapid cool-down characteristics and small gas consumption. In the cold environmental condition, the Joule-Thomson refrigerator has high mass flow rate during cool-down process and in steady state.

  17. Godfrey Thomson and the Rise of University Pedagogical Study: A Recorded Lecture Delivered at the University of Edinburgh in November 1950 by Godfrey H. Thomson--A Transcript with Commentary

    ERIC Educational Resources Information Center

    Lawn, Martin; Deary, Ian J.; Brett, Caroline; Bartholomew, David J.

    2009-01-01

    Professor Sir Godfrey Thomson is one of the key foundational actors in the history of the educational sciences in the UK. At a time when educational studies and the study of educational psychology were very closely linked, in the decades of the mid-twentieth century, Thomson was a crucial figure in education research. He is known for his work on…

  18. Experimental evidence of predominantly transverse electron plasma waves driven by stimulated Raman scattering of picosecond laser pulses.

    PubMed

    Rousseaux, C; Baton, S D; Bénisti, D; Gremillet, L; Adam, J C; Héron, A; Strozzi, D J; Amiranoff, F

    2009-05-01

    We report on highly time- and space-resolved measurements of the evolution of electron plasma waves driven by stimulated Raman scattering of a picosecond, single laser speckle propagating through a preformed underdense plasma. Two-dimensional Thomson scatter spectra indicate that the dominant waves have significant transverse components. These results are supported by particle-in-cell simulations which pinpoint the dominant role of the wave front bowing and of secondary nonlinear electrostatic instabilities in the evolution of the plasma waves.

  19. Clogging of Joule-Thomson Devices in Liquid Hydrogen Handling

    NASA Technical Reports Server (NTRS)

    Jurns, John M.; Lekki, John D.

    2009-01-01

    Experiments conducted at the NASA Glenn Research Center indicate that Joule-Thomson devices become clogged when transferring liquid hydrogen (LH2), operating at a temperature range from 20.5 to 24.4 K. Blockage does not exist under all test conditions but is found to be sensitive to the inlet temperature of the LH2. At a subcooled inlet temperature of 20.5 K blockage consistently appears but is dissipated when the fluid temperature is raised above 24.5 K. Clogging steadily reduced flow rate through the orifices, eventually resulting in complete blockage. This tendency poses a threat to spacecraft cryogenic propulsion systems that would utilize passive thermal control systems. We propose that this clogging is due to trace amounts of neon in the regular LH2 supply. Neon freezes at 24.5 K at one atmosphere pressure. It is postulated that between 20.5 and 24.5 K, neon remains in a meta-stable, supercooled liquid state. When impacting the face of an orifice, liquid neon droplets solidify and accumulate, blocking flow over time. The purpose of this test program was to definitively quantify the phenomena experimentally by obtaining direct visual evidence of orifice clogging by accretion from neon contaminates in the LH2 flow stream, utilizing state of the art imaging technology. Tests were conducted with LH2 flowing in the temperature range of 20.5 to 24.4 K. Additional imaging was also done at LH2 temperatures with no flow to verify clear view through the orifice.

  20. Multipoint NIR spectroscopy for gross composition analysis of powdered infant formula under various motion conditions.

    PubMed

    Cama-Moncunill, Raquel; Markiewicz-Keszycka, Maria; Dixit, Yash; Cama-Moncunill, Xavier; Casado-Gavalda, Maria P; Cullen, Patrick J; Sullivan, Carl

    2016-07-01

    Powdered infant formula (PIF) is a worldwide, industrially produced, human milk substitute. Manufacture of PIF faces strict quality controls in order to ensure that the product meets all compositional requirements. Near-infrared (NIR) spectroscopy is a rapid, non-destructive and well-qualified technique for food quality assessments. The use of fibre-optic NIR sensors allows measuring in-line and at real-time, and can record spectra from different stages of the process. The non-contact character of fibre-optic sensors can be enhanced by fitting collimators, which allow operation at various distances. The system, based on a Fabry-Perot interferometer, records four spectra concurrently, rather than consecutively as in the "quasi-simultaneous" multipoint NIR systems. In the present study, a novel multipoint NIR spectroscopy system equipped with four fibre-optic probes with collimators was assessed to determine carbohydrate and protein contents of PIF samples under static and motion conditions (0.02, 0.15 and 0.30m/s) to simulate possible industrial scenarios. Best results were obtained under static conditions providing a R(2) of calibration of 0.95 and RMSEP values of 1.89%. Yet, considerably low values of RMSEP, for instance 2.70% at 0.15m/s, were provided with the in-motion predictions, demonstrating the system's potential for in/on-line applications at various levels of speed. The current work also evaluated the viability of using general off-line calibrations developed under static conditions for on/in-line applications subject to motion. To this end, calibrations in both modes were developed and compared. Best results were obtained with specific calibrations; however, reasonably accurate models were obtained with the general calibration. Furthermore, this work illustrated independency of the collimator-probe setup by characterizing PIF samples simultaneously recorded according to their carbohydrate content, even when measured under different conditions. Therefore

  1. Ionospheric Cubeswarm Concept Study: using low-resource instrumentation for truly multipoint in situ ionospheric observations

    NASA Astrophysics Data System (ADS)

    Hampton, D.; Lynch, K. A.; Earle, G. D.; Mannucci, A. J.; Clayton, R.; Fisher, L. E.; Fernandes, P. A.; Roberts, M.; Zettergren, M. D.

    2015-12-01

    Magnetosphere-ionosphere coupling currents close in the nightside lower ionosphere. These spatially inhomogeneous and time varying volume currents are difficult to capture with in situ observations. Our understanding of M-I coupling systems is limited by our understanding of the actual structure of ionospheric current closure. A path forward includes assimilation of a variety of data sets into increasingly capable ionospheric models. While each data set provides only a piece of the picture, the assimilation process allows optimal use of each piece.An important development for the necessary in situ observations involves making them truly multi-point, and therefore, low-resource. For thermal particle observations, the high densities of the lower ionosphere allow the use of low-gain (current-sensing rather than particle-counting) particle sensors. One observational goal is the definition of the actual structure of ionospheric closure currents. This can be approached with a number of different measurement techniques, in tandem with an ionospheric model, since the closure currents need to follow the rules of electrodynamics and current continuity. Low resource thermal plasma sensors such as retarding potential analyzers and drift meters can provide valuable measurements of plasma parameters, including density and plasma flow, without the need for high voltages or deployable boom systems. These low-resource measurements, which can be reproduced on arrays of in situ observation platforms, used in tandem with proper plasma physics interpretation of their signatures in the disturbed observing environment, and as part of an assimilated data set into an ionospheric model, can allow us to progress in our understanding of ionospheric structuring and its effects on auroral coupling. Now, with increasingly capable multipoint arrays of spacecraft, and quantitative 2D-with-time context from cameras and imagery, we are moving toward truly multipoint studies of the system

  2. 75 FR 1015 - Directing Certain Actions with Respect to Acquisition and Use of Thomson Correctional Center to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-08

    .... (Presidential Sig.) THE WHITE HOUSE, Washington, December 15, 2009 [FR Doc. 2010-227 Filed 1-7-10; 8:45 am... expeditiously as possible with respect to the facility known as the Thomson Correctional Center (TCC) in Thomson, Illinois: 1. The Attorney General shall acquire and activate the TCC as a United States Penitentiary,...

  3. Closed-Cycle Joule Thomson Cryocooler for Resistance Thermometer Calibration down to 0.65K

    NASA Astrophysics Data System (ADS)

    Shimazaki, T.; Toyoda, K.; Oota, A.; Nozato, H.; Usuda, T.; Tamura, O.

    2008-02-01

    A closed-cycle Joule Thomson cryocooler for resistance thermometer calibration has been developed. It consists of a Gifford McMahon mechanical refrigerator and a closed-cycle 3He Joule Thomson expansion circuit that utilizes the isenthalpic expansion of 3He for cooling. The developed cryocooler can reach temperatures as low as 0.6K and can operate for months with a simple procedure. The typical cooling power of the cryocooler is 1mW at 0.65K with a molar flow rate of 160μmol ·s-1 through the 3He Joule Thomson circuit. The possible mechanical vibration level experienced by the resistance thermometers was measured with a laser vibrometer. It was confirmed that the maximum acceleration level is 0.1m· s-2 and will not cause a problem for thermometer calibration.

  4. An Account of ... William Cullen: John Thomson and the Making of a Medical Biography.

    PubMed

    Shuttleton, David E

    2014-01-01

    John Thomson's An Account of the Life, Lectures and Writings of William Cullen (1832; 1859) remains a primary source for the career of the most influential academic physician in eighteenth-century Scotland and is also a significant work of medical history. But this multi-authored text, begun around 1810 by the academic surgeon, John Thomson, but only completed in 1859 by Dr David Craigie, has its own complex history. This chapter addresses what this history can reveal about the development of medical biography as a literary genre. It argues that the Account is a hybrid work shaped by a complex array of practical, domestic, intellectual, and professional pressures, as Thomson, in seeking to bolster his own career, was caught between the demands of Cullen's children for a traditional "Life" and his own more theoretical and socio-cultural interests.

  5. Characterization of Miniature Millimeter-Wave Vivaldi Antenna for Local Multipoint Distribution Service

    NASA Technical Reports Server (NTRS)

    Simon, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents first, an efficient measurement technique to characterize the input impedance of a Vivaldi antenna, second, a simple technique to impedance match a Vivaldi antenna to a 50 Ohm feed line and lastly, a desktop arrangement to determine the directional gain of a Vivaldi antenna. The characterization is done using a microwave wafer probe station, a ground-signal microwave probe, impedance standard substrate and an automatic network analyzer. The Vivaldi antenna with a matching transformer has a VSVIR close to unity and a gain of about 10 dB over the frequency band of 27.5 to 28.35 GHz which is allocated for local multipoint distribution service (LMDS).

  6. Multipoint-emitting optical fibers for spatially addressable in vivo optogenetics.

    PubMed

    Pisanello, Ferruccio; Sileo, Leonardo; Oldenburg, Ian A; Pisanello, Marco; Martiradonna, Luigi; Assad, John A; Sabatini, Bernardo L; De Vittorio, Massimo

    2014-06-18

    Optical stimulation and silencing of neural activity is a powerful technique for elucidating the structure and function of neural circuitry. In most in vivo optogenetic experiments, light is delivered into the brain through a single optical fiber. However, this approach limits illumination to a fixed volume of the brain. Here a focused ion beam is used to pattern multiple light windows on a tapered optical fiber. We show that such fibers allow selective and dynamic illumination of different brain regions along the taper. Site selection is achieved by a simple coupling strategy at the fiber input, and the use of a single tapered waveguide minimizes the implant invasiveness. We demonstrate the effectiveness of this approach for multipoint optical stimulation in the mammalian brain in vivo by coupling the fiber to a microelectrode array and performing simultaneous extracellular recording and stimulation at multiple sites in the mouse striatum and cerebral cortex. PMID:24881834

  7. A synchronized multipoint vision-based system for displacement measurement of civil infrastructures.

    PubMed

    Ho, Hoai-Nam; Lee, Jong-Han; Park, Young-Soo; Lee, Jong-Jae

    2012-01-01

    This study presents an advanced multipoint vision-based system for dynamic displacement measurement of civil infrastructures. The proposed system consists of commercial camcorders, frame grabbers, low-cost PCs, and a wireless LAN access point. The images of target panels attached to a structure are captured by camcorders and streamed into the PC via frame grabbers. Then the displacements of targets are calculated using image processing techniques with premeasured calibration parameters. This system can simultaneously support two camcorders at the subsystem level for dynamic real-time displacement measurement. The data of each subsystem including system time are wirelessly transferred from the subsystem PCs to master PC and vice versa. Furthermore, synchronization process is implemented to ensure the time synchronization between the master PC and subsystem PCs. Several shaking table tests were conducted to verify the effectiveness of the proposed system, and the results showed very good agreement with those from a conventional sensor with an error of less than 2%.

  8. Surface-sensitive conductivity measurement using a micro multi-point probe approach

    NASA Astrophysics Data System (ADS)

    Perkins, Edward; Barreto, Lucas; Wells, Justin; Hofmann, Philip

    2013-03-01

    An instrument for microscale electrical transport measurements in ultra-high vacuum is presented. The setup is constructed around collinear lithographically-created multi-point probes with a contact spacing down to 500 nm. Most commonly, twelve-point probes are used. These probes are approached to the surface via piezoelectric positioners. Standard four-point resistance measurements can be performed using any combination of contacts out of the twelve available. Current/voltage measurements are taken semi-automatically for a variety of the possible contact configurations, effectively emulating measurements with an equidistant four-point probe for a wide range of contact spacings. In this way, it is possible to distinguish between bulk-like and surface-like conduction. The paper describes the design of the instrument and the approach to data and error analysis. Application examples are given for epitaxial graphene on SiC and degenerately doped Bi2Se3.

  9. Deployment design of wireless sensor network for simple multi-point surveillance of a moving target.

    PubMed

    Tsukamoto, Kazuya; Ueda, Hirofumi; Tamura, Hitomi; Kawahara, Kenji; Oie, Yuji

    2009-01-01

    In this paper, we focus on the problem of tracking a moving target in a wireless sensor network (WSN), in which the capability of each sensor is relatively limited, to construct large-scale WSNs at a reasonable cost. We first propose two simple multi-point surveillance schemes for a moving target in a WSN and demonstrate that one of the schemes can achieve high tracking probability with low power consumption. In addition, we examine the relationship between tracking probability and sensor density through simulations, and then derive an approximate expression representing the relationship. As the results, we present guidelines for sensor density, tracking probability, and the number of monitoring sensors that satisfy a variety of application demands.

  10. Approaching Solar Maximum 24 with Stereo-Multipoint Observations of Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Dresing, N.; Cohen, C. M. S.; Gomez-Herrero, R.; Heber, B.; Klassen, A.; Leske, R. A.; Mason, G. M.; Mewaldt, R. A.; von Rosenvinge, T. T.

    2014-01-01

    Since the beginning of the Solar Terrestrial Relations Observatory (STEREO) mission at the end of 2006, the two spacecraft have now separated by more than 130? degrees from the Earth. A 360-degree view of the Sun has been possible since February 2011, providing multipoint in situ and remote sensing observations of unprecedented quality. Combining STEREO observations with near-Earth measurements allows the study of solar energetic particle (SEP) events over a wide longitudinal range with minimal radial gradient effects. This contribution provides an overview of recent results obtained by the STEREO/IMPACT team in combination with observations by the ACE and SOHO spacecraft. We focus especially on multi-spacecraft investigations of SEP events. The large longitudinal spread of electron and 3He-rich events as well as unusual anisotropies will be presented and discussed.

  11. Alternative licensing arrangements and spectrum economics: The case of multipoint distribution service

    NASA Technical Reports Server (NTRS)

    Agnew, C. E.

    1981-01-01

    At present, the Federal Communications Commission assigns radio licenses following a determination of the public interest. Whenever mutually conflicting license applications are filed, the Commission holds a comparative hearing. This assignment mechanism is criticized as cumbersome and unrealiable, and three alternatives are proposed: increasing the available spectrum, and either auctions or lotteries of radio licenses. An analysis is presented of the present system and these alternative arrangments for assigning rights to the frequency spectrum for the Multipoint Distribution Service (MDS). Although MDS is a relatively minor radio service, it serves as a prototype for message distribution services with a large potential for use in business communications. Moreover, the way in which the initial batch of MDS licenses was assigned provides a unique opportunity for empirical work on the economics of the licensing process.

  12. Multipoint-emitting optical fibers for spatially addressable in vivo optogenetics.

    PubMed

    Pisanello, Ferruccio; Sileo, Leonardo; Oldenburg, Ian A; Pisanello, Marco; Martiradonna, Luigi; Assad, John A; Sabatini, Bernardo L; De Vittorio, Massimo

    2014-06-18

    Optical stimulation and silencing of neural activity is a powerful technique for elucidating the structure and function of neural circuitry. In most in vivo optogenetic experiments, light is delivered into the brain through a single optical fiber. However, this approach limits illumination to a fixed volume of the brain. Here a focused ion beam is used to pattern multiple light windows on a tapered optical fiber. We show that such fibers allow selective and dynamic illumination of different brain regions along the taper. Site selection is achieved by a simple coupling strategy at the fiber input, and the use of a single tapered waveguide minimizes the implant invasiveness. We demonstrate the effectiveness of this approach for multipoint optical stimulation in the mammalian brain in vivo by coupling the fiber to a microelectrode array and performing simultaneous extracellular recording and stimulation at multiple sites in the mouse striatum and cerebral cortex.

  13. Mass- and energy-analyses of ions from plasma by means of a miniature Thomson spectrometer

    SciTech Connect

    Sadowski, M. J.; Czaus, K.; Malinowski, K.; Skladnik-Sadowska, E.; Zebrowski, J.

    2009-05-15

    The paper presents an improved version of a miniature mass-spectrometer of the Thomson-type, which has been adopted for ion analysis near the dense plasma region inside a vacuum chamber. Problems connected with the separation of ions from plasma streams are considered. Input diaphragms and pumping systems, needed to ensure good vacuum inside the analyzing region, are described. The application of the miniature Thomson-type analyzer is illustrated by ion parabolas recorded in plasma-focus facility and rod plasma injector experiment. A quantitative analysis of the recorded ion parabolas is presented. Factors influencing accuracy of the ion analysis are discussed and methods of the spectrometer calibration are described.

  14. An ethics ensemble: abortion, Thomson, Finnis and the case of the violin-player.

    PubMed

    Williams, Melanie

    2004-09-01

    This paper considers approaches to the ethics of abortion and putative links to "rights" debates. In particular, it revisits two papers on the topic from the early 1970's, written by Judith Jarvis Thomson and John Finnis respectively. Consideration of the discourse produced by these papers to some extent reveals the strategic importance of linguistic and conceptual organisation--the rhetorical forces underlying claims to disinterested, analytical standing. In particular, the paper reviews the practical ethics analogy proposed by Thomson; the deployment of "Hohfeldian" rights analysis by John Finnis, the link to the abortion debate and the broader implications of such deployment in its relation to current "rights" discourse. PMID:16602213

  15. Onciderini Thomson, 1860 (Coleoptera: Cerambycidae: Lamiinae) types of The Natural History Museum (BMNH).

    PubMed

    Nearns, Eugenio H; Barclay, Maxwell V L; Tavakilian, Gérard L

    2014-08-28

    The primary types of Onciderini Thomson, 1860 deposited at The Natural History Museum (BMNH), London, United Kingdom, are catalogued and illustrated. Data on the original combination, current name, and type locality are verified and presented. There are 39 primary types of Onciderini including 11 in Oncideres Lacordaire, 1830; and three each in Hesycha Fairmaire & Germain, 1859; Hypselomus Perty, 1832; Lamia Fabricius, 1775; and Tybalmia Thomson, 1868. Of the 39 primary types, 17 were described by H. W. Bates and seven by F. P. Pascoe. Five lectotypes are designated. Notes on additional Onciderini types once believed to be deposited at the BMNH are presented. 

  16. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts.

    PubMed

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  17. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts

    NASA Astrophysics Data System (ADS)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  18. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts.

    PubMed

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests. PMID:27475551

  19. Euconnus franzi Asenjo, new name on  Neotropical Euconnus Thomson (Coleoptera: Staphylinidae: Scydmaeninae: Glandulariini).

    PubMed

    Asenjo, Angélico

    2016-01-01

    During my doctoral studies, while assembling a taxonomic list of the Staphylindae of Brazil (Asenjo et al. 2013: 229), I found a primary junior homonym in the genus Euconnus Thomson. The purpose of this note is to provide a correction to this problem.

  20. Thomson develops new optical reader, digital switching system: Gigadisc reader recorder

    NASA Astrophysics Data System (ADS)

    Levy, D.

    1984-01-01

    A digital optical disk, newly developed by Thomson of France, is announced. The disk, which has a greatly enhanced data storage capacity, is capable of capturing a leading position in information processing and business communications systems by overtaking the share of the market now held by the flexible magnetic disk. A marketing strategy is presented.