WorldWideScience

Sample records for linear thomson scattering

  1. Advanced Thomson scattering system for high-flux linear plasma generator

    NARCIS (Netherlands)

    Meiden, van der H.J.; Lof, A.R.; Berg, van den M.A.; Brons, S.; Donné, A.J.H.; Eck, van H.J.N.; Koelman, Peter; Koppers, W.R.; Kruijt, O.G.; Naumenko, N.N.; Oyevaar, T.; Prins, P.R.; Rapp, J.; Scholten, J.; Schram, D.C.; Smeets, P.H.M.; Star, van der G.; Tugarinov, S.N.; Zeijlmans van Emmichoven, P.A.

    2012-01-01

    An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f /3) transmission grating

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Thomson Scattering

    NARCIS (Netherlands)

    Donne, A. J. H.

    1994-01-01

    Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is

  4. Incoherent Thomson scattering

    NARCIS (Netherlands)

    Donne, A. J. H.

    1996-01-01

    Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is

  5. Excess noise in Lidar Thomson scattering methods

    International Nuclear Information System (INIS)

    Smith, R J; Drake, L A P; Lestz, J B

    2012-01-01

    Fundamental detection limits for the Lidar Thomson scattering technique and in particular pulsed polarimetry are presented for the first time for the long wavelength limit of incoherent Thomson scattering. Pulsed polarimetry generalizes Lidar Thomson scattering to include local magnetic field sensing. The implication for these techniques is explored for two experimental regimes where shot limited detection no longer applies: tokamaks of ITER size and cm-size wire Z pinch plasmas of High Energy Density (HED) science. The utility and importance of developing Lidar Thomson scattering at longer wavelengths for the magnetic fusion program is illustrated by a study of sightline (local) polarimetry measurements on a 15MA ITER scenario. Polarimetric measurements in the far infrared regime are shown to reach sensitivities that are instructive and useful but with a complex behaviour that make spatially resolved measurements all but mandatory.

  6. Rotational Raman scattering using molecular nitrogen gas for calibration of Thomson-scattering apparatus

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Nakazawa, Ichiro

    1987-01-01

    Anti-Stokes rotational Raman lines in molecular nitrogen gas were used for the calibration of Thomson-scattering apparatus. It was found that molecular nitrogen gas is suitable for a vessel having strong stray light. The polarization ratio was 0.16 using linear-polarized laser light. (author)

  7. Thomson scattering using an atomic notch filter

    NARCIS (Netherlands)

    Bakker, L.P.; Freriks, J.M.; Hoog, de F.J.; Kroesen, G.M.W.

    2000-01-01

    One of the biggest problems in performing Thomson scattering experiments in low-density plasmas is the very high stray light intensity in comparison with the Thomson scattering intensity. This problem is especially present in fluorescent lamps because of the proximity of the glass tube. We propose

  8. LIDAR Thomson scattering

    International Nuclear Information System (INIS)

    1991-07-01

    This collection contains 21 papers on the application and development of LIDAR (Light Detection and Ranging) Thomson scattering techniques for the determination of spatially resolved electron temperature and density in magnetic confinement experiments, particularly tokamaks. Refs, figs and tabs

  9. Equipment of Thomson scattering measurement on DIVA plasma

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Kumagai, Katsuaki; Funahashi, Akimasa; Matoba, Thoru; Sengoku, Seio

    1980-02-01

    Equipment of Thomson scattering measurement using ruby-laser light is explained. DIVA device was shut down in September 1979; it gave numerous fruitful experimental results during its five years operation. We measured the profiles of electron temperature and density with the Thomson scattering equipment, which played an important role in research of the energy confinement and heating characteristics. In Thomson scattering measurements on DIVA, studies and improvements were made for reduction of stray light, increase of measuring points and data processing. The profile of electron temperature and density were thus measured successful. In this report is given an over-all view of the Thomson scattering equipment together with the above improvements. As two representative examples, the measured results of electron temperature profiles on DIVA plasma under divertor operation and low-q discharge respectively are described. (author)

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

    International Nuclear Information System (INIS)

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

    2004-01-01

    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

  11. Alpha particle collective Thomson scattering in TFTR

    International Nuclear Information System (INIS)

    Machuzak, J.S.; Woskov, P.P.; Rhee, D.Y.; Gilmore, J.; Bindslev, H.

    1993-01-01

    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

  12. 3. Laser Thomson scattering by plasmas. 3.2. Applications of incoherent Thomson scattering. 3.2.2. Incoherent Thomson scattering systems for JT-60U and JFT-2M

    International Nuclear Information System (INIS)

    Hatae, Takaki; Yoshida, Hidetoshi; Naito, Osamu; Yamauchi, Toshihiko

    2000-01-01

    Development of Thomson scattering diagnostics for the JT-60U and JFT-2M Tokamaks are described. Two Thomson scattering systems have been installed on JT-60U. The first system uses two ruby lasers (10 J, 0.25 Hz) and measures electron temperature (T e ) and density (n e ) profiles of 60 spatial points with high spatial resolution (8 mm). The second system uses a YAG laser (2 J, 30 Hz) and measures time evolution of T e and n e profiles with 15 spatial points. On JFT-2M, a TV Thomson Scattering system (TVTS) has been installed and measures at 81 spatial points with high spatial resolution (8.6 mm). These systems have provided not only profiles of all over the plasma, but successfully measured local structures to study various physics issues; e.g. H-mode edge pedestal, internal transport barrier, local MHD event. (author)

  13. Progress in development of the advanced Thomson scattering diagnostics

    International Nuclear Information System (INIS)

    Hatae, T; Naito, O; Howard, J; Ebizuka, N; Yoshida, H; Nakatsuka, M; Fujita, H; Kajita, S; Narihara, K; Yamada, I; Funaba, H; Hirano, Y; Koguchi, H

    2010-01-01

    We have been studied the advanced Thomson scattering diagnostics from viewpoints of new concepts, laser technology and spectrum analysis. This paper summarizes results of development on technologies for advanced Thomson scattering diagnostics.

  14. Stray light reduction for Thomson scattering

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.; Doebele, H.F.; Muraoka, K.

    1999-01-01

    In order to perform Thomson scattering in a gas discharge tube, the reduction of stray light is very important because of the very small Thomson cross-section. By introducing a sodium absorption cell as a notch filter, we can reduce the measured stray light considerably. Then we have to use a dye

  15. LIDAR Thomson scattering for advanced tokamaks. Final report

    International Nuclear Information System (INIS)

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

    1996-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Vais, O. E.; Bochkarev, S. G., E-mail: bochkar@sci.lebedev.ru; Bychenkov, V. Yu. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2016-09-15

    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{sub 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.

  17. Theory of Thomson scattering in inhomogeneous media.

    Science.gov (United States)

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

    2016-04-12

    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.

  18. Multichannel Thomson scattering apparatus

    International Nuclear Information System (INIS)

    Bretz, N.; Dimock, D.; Foote, V.; Johnson, D.; Long, D.; Tolnas, E.

    1977-07-01

    A Thomson scattering apparatus for measuring the electron temperature and density along a 90 cm diameter of the PLT plasma has been built. A wide angle objective images the 3 mm x 900 mm ruby laser beam onto an image dissector which rearranges the 300 : 1 image to 20 : 1 forming the input slit of a spectrometer. The stigmatic spectrometer provides 20 wavelength elements of approximately 70 A each. A micro-channel-plate image intensifier optically coupled to a cooled SIT tube provides detection with single frame linearity and 1000 : 1 dynamic range. Spatial profiles of N/sub e/ and T/sub e/ in the range 10 13 - 10 14 cm -3 and 0.05 - 3 keV have an accuracy of 30 √10 13 /N/sub e/ (cm -3 ) percent per 1.2 cm element

  19. A triple spectrograph system for low stray light Thomson scattering measurements

    NARCIS (Netherlands)

    Sande, van de M.J.; Mullen, van der J.J.A.M.

    2001-01-01

    Thomson scattering is scattering of photons by the electrons in a plasma. From the scattering spectrum, the electron temperature and density (Te, ne) of the plasma can be deduced. In the past decade, the development of high power lasers and sensitive detection devices has made Thomson scattering a

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

    Science.gov (United States)

    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.

  1. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Larsen, Axel Wright; Meo, Fernando

    2005-01-01

    The EFDA Contract 04-1213 with Risø National Laboratory concerning a detailed integrated design of a Fast Ion Collective Thomson Scattering (CTS) diagnostic for ITER was signed on 31 December 2004. In 2003 the Risø CTS group finished a feasibility study and a conceptual design of an ITER Fast Ion...... Collective Thomson Scattering System (Contract 01.654) [1, 2]. The purpose of the CTS diagnostic is to measure the distribution function of fast ions in the plasma. The feasibility study demonstrated that the only system that can fully meet the ITER measurement requirements for confined fusion alphas is a 60...... the blanket gap, and calculations of diagnosing fuel ion ratio and rotation velocity by CTS....

  2. Detectors for LIDAR type Thomson scattering diagnostics

    International Nuclear Information System (INIS)

    Hirsch, K.

    1991-04-01

    A report on the capability of the microchannel plate photomultiplier type (ITT F4128) presently used at the JET LIDAR Thomson Scattering System is given. Detailed investigation on time response, low noise amplification, shutter ratio, gating behaviour, linear mode of operation and saturation pulse recovery carried out during the design phase for LIDAR are presented. New investigation with respect to dc- and gated operation showed no measurable changes in sensitivity of this MCP photomultiplier. Comparing this type of detector with other MCP photomultipliers and with streak cameras some detection schemes for future LIDAR type diagnostic are proposed. (orig.)

  3. Thomson scattering in a low-pressure argon mercury positive column

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2000-01-01

    The electron density and the electron temperature in a low-pressure argon mercury positive column are determined using Thomson scattering. Special attention has been given to the stray light reduction in the Thomson scattering setup. The results are obtained in a discharge tube with a 26 mm diam, 5

  4. Thomson scattering in a low-pressure neon mercury positive column

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2001-01-01

    The electron density and the electron temperature in a low-pressure neon mercury positive column are determined using Thomson scattering. Special attention has been given to the stray light reduction in the Thomson scattering setup. The results are obtained in a discharge tube with a 26 mm diam, 10

  5. Incoherent Thomson scattering as a diagnostic tool

    NARCIS (Netherlands)

    Barth, C. J.

    1998-01-01

    Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wavelength is much smaller than the plasma Debye length, the total scattered power is

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

    NARCIS (Netherlands)

    Carbone, E.A.D.; Nijdam, S.

    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

  7. Gated integrator PXI-DAQ system for Thomson scattering diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kiran, E-mail: kkpatel@ipr.res.in; Pillai, Vishal; Singh, Neha; Thomas, Jinto; Kumar, Ajai

    2017-06-15

    Gated Integrator (GI) PXI based data acquisition (DAQ) system has been designed and developed for the ease of acquiring fast Thomson Scattered signals (∼50 ns pulse width). The DAQ system consists of in-house designed and developed GI modules and PXI-1405 chassis with several PXI-DAQ modules. The performance of the developed system has been validated during the SST-1 campaigns. The dynamic range of the GI module depends on the integrating capacitor (C{sub i}) and the modules have been calibrated using 12 pF and 27 pF integrating capacitors. The developed GI module based data acquisition system consists of sixty four channels for simultaneous sampling using eight PXI based digitization modules having eight channels per module. The error estimation and functional tests of this unit are carried out using standard source and also with the fast detectors used for Thomson scattering diagnostics. User friendly Graphical User Interface (GUI) has been developed using LabVIEW on Windows platform to control and acquire the Thomson scattering signal. A robust, easy to operate and maintain with low power consumption, having higher dynamic range with very good sensitivity and cost effective DAQ system is developed and tested for the SST-1 Thomson scattering diagnostics.

  8. High resolution Thomson scattering system for steady-state linear plasma sources

    Science.gov (United States)

    Lee, K. Y.; Lee, K. I.; Kim, J. H.; Lho, T.

    2018-01-01

    The high resolution Thomson scattering system with 63 points along a 25 mm line measures the radial electron temperature (Te) and its density (ne) in an argon plasma. By using a DC arc source with lanthanum hexaboride (LaB6) electrode, plasmas with electron temperature of over 5 eV and densities of 1.5 × 1019 m-3 have been measured. The system uses a frequency doubled (532 nm) Nd:YAG laser with 0.25 J/pulse at 20 Hz. The scattered light is collected and sent to a triple-grating spectrometer via optical-fibers, where images are recorded by an intensified charge coupled device (ICCD) camera. Although excellent in stray-light reduction, a disadvantage comes with its relatively low optical transmission and in sampling a tiny scattering volume. Thus requires accumulating multitude of images. In order to improve photon statistics, pixel binning in the ICCD camera as well as enlarging the intermediate slit-width inside the triple-grating spectrometer has been exploited. In addition, the ICCD camera capture images at 40 Hz while the laser is at 20 Hz. This operation mode allows us to alternate between background and scattering shot images. By image subtraction, influences from the plasma background are effectively taken out. Maximum likelihood estimation that uses a parameter sweep finds best fitting parameters Te and ne with the incoherent scattering spectrum.

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

    Energy Technology Data Exchange (ETDEWEB)

    Follett, R. K., E-mail: rfollett@lle.rochester.edu; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

    2016-11-15

    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 10{sup 21} cm{sup −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.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

    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

  11. Study of the effects of photoelectron statistics on Thomson scattering data

    International Nuclear Information System (INIS)

    Hart, G.W.; Levinton, F.M.; McNeill, D.H.

    1986-01-01

    A computer code has been developed which simulates a Thomson scattering measurement, from the counting statistics of the input channels through the mathematical analysis of the data. The scattered and background signals in each of the wavelength channels are assumed to obey Poisson statistics, and the spectral data are fitted to a Gaussian curve using a nonlinear least-squares fitting algorithm. This method goes beyond the usual calculation of the signal-to-noise ratio for the hardware and gives a quantitative measure of the effect of the noise on the final measurement. This method is applicable to Thomson scattering measurements in which the signal-to-noise ratio is low due to either low signal or high background. Thomson scattering data from the S-1 spheromak have been compared to this simulation, and they have been found to be in good agreement. This code has proven to be useful in assessing the effects of counting statistics relative to shot-to-shot variability in producing the observed spread in the data. It was also useful for designing improvements for the S-1 Thomson scattering system, and this method would be applicable to any measurement affected by counting statistics

  12. The Thomson scattering system at DANTE

    International Nuclear Information System (INIS)

    Gadeberg, M.

    1983-08-01

    The construction and operation of the 90 deg Thomson Scattering diagnostic at DANTE is described. The system is based on a double-pulse ruby laser and a three channel spectrometer. Two single point measurements can be made during each plasma discharge. (Auth.)

  13. Recent advances in Thomson scattering: high repetition rate Thomson scattering diagnostics on large plasma devices

    International Nuclear Information System (INIS)

    Roehr, H.; Steuer, K.H.; Hirsch, K.; Salzmann, H.

    1982-09-01

    In contrast to conventional ruby laser scattering devices allowing only singly pulse measurements, time evolution of Te and ne can be obtained with multipulse lasers. Within a short time interval ( proportional 1 ms) rapid variations can be investigated by employing a periodically Q-switched ruby laser. Several scattering systems under construction in different laboratories to register the time evolution of Tsub(e) and nsub(e) during the whole plasma discharge will be reported. The set-up operating successfully on the Garching tokamak ASDEX will be described in detail. This scattering system uses a Nd:YAG laser (1 J/pulse, up to 100 pps, pulse duration 30 ns, burst of max. 400 pulses) and silicon avalanche diodes as detectors. Time resolved nsub(e) and Tsub(e) measurements on different types of ASDEX discharges are shown, e.g. the electron density and electron heating during neutral beam injection in a divertor discharge. As an example of relatively fast changes of nsub(e) and Tsub(e), results on pellet injection are presented. Interferometric and ECE measurements are in good agreement with the Thomson results. Stationary ''long pulse discharges'' in ASDEX (10 s) at low densitites (10 12 cm -3 ) were diagnosed with reduced time resolution by averaging over several laser pulses. Measurements of the time evolution of electron temperature and -density profiles were done in a first step with a scanning mirror system. These results enables optimazing out 15 spatial-point Thomson scattering system on ASDEX. (orig./AH)

  14. Upgraded divertor Thomson scattering system on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Glass, F., E-mail: glassf@fusion.gat.com; Carlstrom, T. N.; Du, D.; Taussig, D. A.; Boivin, R. L. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); McLean, A. G. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    2016-11-15

    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 (T{sub e} in the range of 0.5 eV–2 keV, n{sub e} in the range of 5 × 10{sup 18}–1 × 10{sup 21} m{sup 3}) for both low T{sub e} in detachment and high T{sub e} measurement up beyond the separatrix.

  15. Thomson scattering on the PRETEXT Tokamak

    International Nuclear Information System (INIS)

    McCool, S.C.

    1982-03-01

    Ruby laser Thomson scattering was performed on the PRETEXT tokamak. A 10 Joule Q-switched laser and a 1 meter 10 channel polychromator were used to diagnose the electron temperature and density profiles in the PRETEXT plasma. These parameters were measured as a function of time and radial position on a shot to shot basis. The density measurement was calibrated by Rayleigh and Raman scattering and by comparison with data from a 4 mm microwave interferometer. Electron densities ranging from 1 x 10 12 cm -3 to 2 x 10 13 cm -3 and temperatures ranging from 3 eV to 400 eV were observed. Detailed measurements were made throughout the 40 ms discharge with particular emphasis on the current rise phase. The Thomson scattering data was used as input to a one dimensional magnetic diffusion code. This code modelled the evolution of the current density and safety factor profiles. The results of this analysis were compared with existing theories of tokamak current penetration. The growth of resitive MHD tearing modes was proposed as a likely explanation for the anomalously rapid current penetration observed in PRETEXT

  16. LIDAR Thomson scattering for ITER core plasma revisited

    International Nuclear Information System (INIS)

    Gowers, C.; Nielsen, P.; Salzmann, H.

    2016-01-01

    The authors have become aware that the development of the hitherto planned time-of-flight Thomson scattering system for the ITER core plasma is not proceeding and that conventional Thomson scattering set-ups are being discussed as an alternative. In this paper, we want to point out the advantages of LIDAR and show how criticized details of the original design can be improved. We present a design of the front optics, which in neutronics terms closely resembles a layout already previously accepted. The presented design does not require Raman scattering calibration for the density measurement. Comparison with the JET Core LIDAR system and simulations at higher temperatures both show that with the new design the specified accuracy can be met with a 1–2 J laser. Current laser and detector technology is reviewed. A strategy for how to proceed is presented

  17. Thomson scattering measurements in atmospheric plasma jets

    International Nuclear Information System (INIS)

    Gregori, G.; Schein, J.; Schwendinger, P.; Kortshagen, U.; Heberlein, J.; Pfender, E.

    1999-01-01

    Electron temperature and electron density in a dc plasma jet at atmospheric pressure have been obtained using Thomson laser scattering. Measurements performed at various scattering angles have revealed effects that are not accounted for by the standard scattering theory. Differences between the predicted and experimental results suggest that higher order corrections to the theory may be required, and that corrections to the form of the spectral density function may play an important role. copyright 1999 The American Physical Society

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

    International Nuclear Information System (INIS)

    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

  19. DIII-D Thomson Scattering Diagnostic Data Acquisition, Processing and Analysis Software

    International Nuclear Information System (INIS)

    Middaugh, K.R.; Bray, B.D.; Hsieh, C.L.; McHarg, B.B.Jr.; Penaflor, B.G.

    1999-01-01

    One of the diagnostic systems critical to the success of the DIII-D tokamak experiment is the Thomson scattering diagnostic. This diagnostic is unique in that it measures local electron temperature and density: (1) at multiple locations within the tokamak plasma; and (2) at different times throughout the plasma duration. Thomson ''raw'' data are digitized signals of scattered light, measured at different times and locations, from the laser beam paths fired into the plasma. Real-time acquisition of this data is performed by specialized hardware. Once obtained, the raw data are processed into meaningful temperature and density values which can be analyzed for measurement quality. This paper will provide an overview of the entire Thomson scattering diagnostic software and will focus on the data acquisition, processing, and analysis software implementation. The software falls into three general categories: (1) Set-up and Control: Initializes and controls all Thomson hardware and software, synchronizes with other DIII-D computers, and invokes other Thomson software as appropriate. (2) Data Acquisition and Processing: Obtains raw measured data from memory and processes it into temperature and density values. (3) Analysis: Provides a graphical user interface in which to perform analysis and sophisticated plotting of analysis parameters

  20. Enhancing detection sensitivity of SST-1 Thomson scattering experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhari, Vishnu; Patel, Kiran; Thomas, Jinto; Kumar, Ajai, E-mail: ajai@ipr.res.in

    2016-10-15

    Thomson Scattering System (TSS) is the main diagnostic to extract electron temperature and density of steady state superconducting (SST-1) tokamak plasma. Silicon avalanche photo diode is used with low noise and fast signal conditioning electronics (SCE) to detect incoming Thomson scattered laser photons. A stringent requirement for the measurement is to detect high speed and low level light signal (detection of 100 numbers of Thomson scattered photons for 50 ns pulse width at input of active area of detector) in the presence of wide band electro-magnetic interference (EMI) noise. The electronics and instruments for different sub-systems kept in laboratory contribute to the radiated and conductive noise in a complex manner to the experiment, which can degrade the resultant signal to noise ratio (SNR <1). In general a repeated trial method with flexible grounding scheme are used to improve system signal to noise ratio, which is time consuming and less efficient. In the present work a simple, robust, cost-effective instrumentation system is used for the measurement and monitoring with improved ground scheme and shielding method to minimize noise, isolating the internal sub-system generated noise and external interference which leads to an improved SNR.

  1. Thomson scattering diagnostic for the microwave tokamak experiment

    International Nuclear Information System (INIS)

    Foote, J.H.; Barter, J.D.; Sewall, N.R.; Jolly, J.J.; Schlander, L.F.

    1990-01-01

    The Thomson scattering diagnostic system (TSS) on the microwave tokamak experiment (MTX) at LLNL routinely monitors electron temperature (T e ) and density. Typical measured values at the plasma center under clean conditions are 900±70 eV and 1--2x10 14 (±30%) cm -3 . The TSS apparatus is compact, with all elements mounted on one sturdy, two-level optics table. Because of this, we maintain with minimum effort the alignment of both the ruby-laser input optics and the scattered-light collecting optics. Undesired background signals, e.g., plasma light as well as ruby-laser light scattered off obstacles and walls, are generally small compared with the Thomson-scattered signals we normally detect. In the MTX T e region, the TSS data are definitely fitted better when relativistic effects are included in the equations. Besides determining the temperature of the Maxwellian electron distribution, the system is designed to detect electron heating from GW-level free-electron laser (FEL) pulses by measuring large wavelength shifts of the scattered laser photons. TSS data suggest that we may indeed be able to detect these electrons, which can have energies up to 10 keV, according to computer simulation

  2. Stimulated Thomson scattering

    International Nuclear Information System (INIS)

    Spencer, R.L.

    1979-03-01

    The theory of stimulated Thomson scattering is investigated both quantum mechanically and classically. Two monochromatic electromagnetic waves of like polarization travelling in opposite directions are allowed to interact for a time tau with the electrons in a collisionless plasma. The electromagnetic waves have frequencies well above the plasma frequency, and their difference frequency is allowed to range upward from the plasma frequency. With the difference frequency well above the plasma frequency, the rate at which energy is transferred from one wave to the other is calculated quantum mechanically, classically from a fluid theory, and classically from an independent electron theory. The rate is calculated in both the homogeneously broadened limit, and in the inhomogeneously broadened limit

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

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Datte, P.; Divol, L.; Galbraith, J.; Hatch, B.; Landen, O.; Manuel, A. M.; Molander, W.; Moody, J. D.; Swadling, G. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Froula, D. H.; Katz, J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kilkenny, J. [General Atomics, San Diego, California 92186 (United States); Montgomery, D. S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Weaver, J. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-11-15

    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 (λ{sub 0} = 210 nm) will be used to Thomson scatter from electron plasma densities of ∼5 × 10{sup 20} cm{sup −3} while a 3ω probe will be used for plasma densities of ∼1 × 10{sup 19} cm{sup −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).

  4. First observation of the depolarization of Thomson scattering radiation by a fusion plasma

    Science.gov (United States)

    Giudicotti, L.; Kempenaars, M.; McCormack, O.; Flanagan, J.; Pasqualotto, R.; contributors, JET

    2018-04-01

    We report the first experimental observation of the depolarization of the Thomson scattering (TS) radiation, a relativistic effect expected to occur in very high {{T}e} plasmas and never observed so far in a fusion machine. A set of unused optical fibers in the collection optics of the high resolution Thomson scattering system of JET has been used to detect the depolarized TS radiation during a JET campaign with {{T}e}≤slant 8 keV . A linear polarizer with the axis perpendicular to the direction of the incident E-field was placed in front of a fiber optic pair observing a region close to the plasma core, while another fiber pair with no polariser simultaneously observed an adjacent plasma region. The measured intensity ratio was found to be consistent with the theory, taking into account sensitivity coefficients of the two measurement channels determined with post-experiment calibrations and Raman scattering. This depolarization effect is at the basis of polarimetric TS, a different and complementary method for the analysis of TS spectra that can provide significant advantages for {{T}e} measurements in very hot plasmas such as in ITER ≤ft({{T}e}≤slant 40 keV \\right) .

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

    International Nuclear Information System (INIS)

    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

  6. Calculation of Thomson scattering spectral fits for interpenetrating flows

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F., E-mail: george.swadling@imperial.ac.uk; Lebedev, S. V., E-mail: george.swadling@imperial.ac.uk; Burdiak, G. C.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Suzuki-Vidal, F. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2JI (Canada); Hall, G. N. [Blackett Laboratory, Imperial College, London, United Kingdom SW7 2BW and Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    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.

  7. Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

    DEFF Research Database (Denmark)

    Salewski, Mirko; Jacobsen, A.S.; Jensen, Thomas

    2016-01-01

    -tonoise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure 푓2퐷푣 in the MeV-range in reactor relevant plasmas...

  8. The ITER Thomson scattering core LIDAR diagnostic

    NARCIS (Netherlands)

    Naylor, G.A.; Scannell, R.; Beurskens, M.; Walsh, M.J.; Pastor, I.; Donné, A.J.H.; Snijders, B.; Biel, W.; Meszaros, B.; Giudicotti, L.; Pasqualotto, R.; Marot, L.

    2012-01-01

    The central electron temperature and density of the ITER plasma may be determined by Thomson scattering. A LIDAR topology is proposed in order to minimize the port access required of the ITER vacuum vessel. By using a LIDAR technique, a profile of the electron temperature and density can be

  9. Thomson scattering diagnostic for the Microwave Tokamak Experiment

    International Nuclear Information System (INIS)

    Foote, J.H.; Barter, J.D.; Sewall, N.R.; Jolly, J.J.; Schlander, L.F.

    1990-01-01

    The Thomson-scattering diagnostic system (TSS) on the Microwave Tokamak Experiment (MTX) at LLNL routinely monitors electron temperature (T e ) and density. Typical measured values at the plasma center under clean conditions are 900 ± 70 eV and 1 to 2 x 10 14 (±30%) cm -3 . The TSS apparatus is compact, with all elements mounted on one sturdy, two-level optics table. Because of this, we maintain with minimum effort the alignment of both the ruby-laser input optics and the scattered-light collecting optics. Undesired background signals, e.g., plasma light as well as ruby-laser light scattered off obstacles and walls, are generally small compared with the Thomson-scattered signals we normally detect. In the MTX T e region, the TSS data are definitely fitted better when relativistic effects are included in the equations. Besides determining the temperature of the Maxwellian electron distribution, the system is designed to detect electron heating from GW-level free-electron laser (FEL) pulses by measuring large wavelength shifts of the scattered laser photons. TSS data suggest that we may indeed by able to detect these electrons, which can have energies up to 10 keV, according to computer simulation. 7 refs., 4 figs

  10. Accurate calculation of high harmonics generated by relativistic Thomson scattering

    International Nuclear Information System (INIS)

    Popa, Alexandru

    2008-01-01

    The recent emergence of the field of ultraintense laser pulses, corresponding to beam intensities higher than 10 18 W cm -2 , brings about the problem of the high harmonic generation (HHG) by the relativistic Thomson scattering of the electromagnetic radiation by free electrons. Starting from the equations of the relativistic motion of the electron in the electromagnetic field, we give an exact solution of this problem. Taking into account the Lienard-Wiechert equations, we obtain a periodic scattered electromagnetic field. Without loss of generality, the solution is strongly simplified by observing that the electromagnetic field is always normal to the direction electron-detector. The Fourier series expansion of this field leads to accurate expressions of the high harmonics generated by the Thomson scattering. Our calculations lead to a discrete HHG spectrum, whose shape and angular distribution are in agreement with the experimental data from the literature. Since no approximations were made, our approach is also valid in the ultrarelativistic regime, corresponding to intensities higher than 10 23 W cm -2 , where it predicts a strong increase of the HHG intensities and of the order of harmonics. In this domain, the nonlinear Thomson scattering could be an efficient source of hard x-rays

  11. Warm dense matter and Thomson scattering at FLASH

    International Nuclear Information System (INIS)

    Faeustlin, Roland Rainer

    2010-05-01

    X-ray free electron lasers are powerful tools to investigate moderately to strongly correlated solid density low temperature plasmas, named warm dense matter. These plasmas are of most interest for astrophysics and laser plasma interaction, particularly inertial confinement fusion. This work utilizes the ultrashort soft x-ray pulse duration and high brilliance of the free electron laser in Hamburg, FLASH, to generate warm dense matter and to study its ultrafast processes. The techniques applied are absorption measurement, emission spectroscopy and Thomson scattering. Radiative hydrodynamics and Thomson scattering simulations are used to investigate the impact of temperature and density gradients in the sample and to fit the experimental data. The measurements result in a comprehensive picture of soft x-ray matter interaction related to warm dense matter and yield insight into ultrafast equilibration and relaxation mechanisms, in particular impact ionization and radiative recombination. (orig.)

  12. Warm dense matter and Thomson scattering at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faeustlin, Roland Rainer

    2010-05-15

    X-ray free electron lasers are powerful tools to investigate moderately to strongly correlated solid density low temperature plasmas, named warm dense matter. These plasmas are of most interest for astrophysics and laser plasma interaction, particularly inertial confinement fusion. This work utilizes the ultrashort soft x-ray pulse duration and high brilliance of the free electron laser in Hamburg, FLASH, to generate warm dense matter and to study its ultrafast processes. The techniques applied are absorption measurement, emission spectroscopy and Thomson scattering. Radiative hydrodynamics and Thomson scattering simulations are used to investigate the impact of temperature and density gradients in the sample and to fit the experimental data. The measurements result in a comprehensive picture of soft x-ray matter interaction related to warm dense matter and yield insight into ultrafast equilibration and relaxation mechanisms, in particular impact ionization and radiative recombination. (orig.)

  13. Experiment of laser thomson scattering at HL-1 tokamak device

    International Nuclear Information System (INIS)

    Zuo Henian; Chen Jiafu; Yan Derong; Liu Aiping; Shi Peilan; Wang Wei; Liu Xiaomei

    1989-05-01

    The structure and performance of the Ruby Laser Thomson Scattering apparatus for HL-1 tokamak device is described. The method of acquisition and calibration of multichannel scattered signals are presented. Examples of measured electron temperature T. with experimental error are given

  14. Design of Amplifier Circuit for the HT-7 Tokamak Thomson Scattering System

    International Nuclear Information System (INIS)

    Shi Lingwei; Ling Bili; Zhao Junyu; Yang Li; Zang Qing; Hu Qingsheng; Jia Yanqing

    2008-01-01

    Thomson scattering diagnostic is important for measuring electron temperature and density profiles. To improve the signal-to-noise ratio, a silicon avalanche photodiode (APD) with high quantum efficiency, high sensitivity, and high gain up to 100 was adopted to measure the Thomson scattering spectrum. A preamplifier, which has low noise, high bandwidth, and high sensitivity, was designed with suitable transimpedance. Using AD8367 as the post-amplifier, good performance of the APD readout electronics have been obtained. A discussion is presented on the performance of the amplifier using a laser diode to simulate the Thomson scattering light. The test results indicate that the designed circuit has a high amplifying factor and fast rising edge. So reduction of the integral gate of the CAMAC ADC converter can improve the signal-to-noise ratio. (brief communication and research note)

  15. Collective Thomson scattering capabilities to diagnose fusion plasmas

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Bindslev, Henrik; Furtula, Vedran

    2010-01-01

    Collective Thomson scattering (CTS) is a versatile technique for diagnosing fusion plasmas. In particular, experiments on diagnosing the ion temperature and fast ion velocity distribution have been executed on a number of fusion devices. In this article the main aim is to describe the technique...

  16. Advances in the FTU collective Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    Bin, W., E-mail: wbin@ifp.cnr.it; Bruschi, A.; Grosso, G.; Alessi, E.; De Angeli, M.; Figini, L.; Garavaglia, S.; Granucci, G.; Lontano, M.; Mellera, V.; Minelli, D.; Moro, A.; Muraro, A.; Nardone, A.; Simonetto, A.; Tartari, U. [Istituto di Fisica del Plasma “P. Caldirola,” Consiglio Nazionale delle Ricerche, Milano (Italy); D’Arcangelo, O.; Castaldo, C.; Centioli, C.; Magagnino, S. [ENEA for EUROfusion, Frascati (Italy); and others

    2016-11-15

    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.

  17. Thomson scattering measurements on an atmospheric Ar dc discharge lamp

    NARCIS (Netherlands)

    Zhu, Xiao-Yan; Redwitz, M.; Kieft, E.R.; Sande, van de M.J.; Mullen, van der J.J.A.M.

    2004-01-01

    Thomson scattering (TS) experiments have been performed in the region near the electrodes of a dc powered model lamp filled with 1-2 bar argon gas. In order to suppress the false stray light and Rayleigh scattered photons, a triple grating spectrograph was used. In this way the electron density and

  18. Feasibility study of direct spectra measurements for Thomson scattered signals for KSTAR fusion-grade plasmas

    Science.gov (United States)

    Park, K.-R.; Kim, K.-h.; Kwak, S.; Svensson, J.; Lee, J.; Ghim, Y.-c.

    2017-11-01

    Feasibility study of direct spectra measurements of Thomson scattered photons for fusion-grade plasmas is performed based on a forward model of the KSTAR Thomson scattering system. Expected spectra in the forward model are calculated based on Selden function including the relativistic polarization correction. Noise in the signal is modeled with photon noise and Gaussian electrical noise. Electron temperature and density are inferred using Bayesian probability theory. Based on bias error, full width at half maximum and entropy of posterior distributions, spectral measurements are found to be feasible. Comparisons between spectrometer-based and polychromator-based Thomson scattering systems are performed with varying quantum efficiency and electrical noise levels.

  19. Vacuum component subsystem of TV Thomson scattering system in JFT-2M

    International Nuclear Information System (INIS)

    Shiina, Tomio; Yamauchi, Toshihiko; Fujisawa, Atsushi; Hanawa, Osamu; Dimock, D.; Takahashi, Akira; Inomata, Shinji.

    1991-03-01

    The vacuum component subsystem, which is one of six subsystems in TV Thomson scattering (TVTS) system for the JFT-2M tokamak, is completed under a US-JAPAN cooperative program. This subsystem is composed of top and bottom flanges, side flange, beam dump, viewing dump and so on. These components are fitted in the existing 13-point Thomson scattering system as well as the TVTS optics newly developed by Princeton Plasma Physics Laboratory (PPPL) in USA. New feedback system of laser beam alignment was designed and developed. (author)

  20. High repetition Thomson scattering profile measurements using a nonimaging technique

    International Nuclear Information System (INIS)

    Zigler, A.

    1983-01-01

    The Thomson scattering technique is one of the most useful diagnostics for the study of magnetically confined plasmas. In this work, a simple multi-space and time Thomson scattering technique has been proposed. The spatial resolution is obtained by conversion of the scattered laser light collected from different plasma points into a time sequence. This can be done by focusing the image of the laser beam through a wideangle lens onto an array of fiber optic light pipes. Since the laser emits relatively short pulses (1020 nsec), scattered light pulses from each of the light pipes can be delayed relative to one another without overlapping. Such delays can be achieved by using an array of fiber optics of differing lengths (2-4 meters). The light is transmitted then into a spectrometer and detected by fast detectros (few nsec rise and fall time). Reconstruction from the time sequence to the spatial structure is obtained by using existing fast gate circuits. The data then is A/D converted and handled by using a data acquisition system

  1. Preliminary project of s Thomson scattering system for the ETE tokamak

    International Nuclear Information System (INIS)

    Berni, Luiz Angelo

    1997-01-01

    This report presents the preliminary project of the injection and laser light block system for the Thomson (ET) scattering diagnostic to be implanted at the ETE spheric tokamak of the Instituto Nacional de Pesquisas Espaciais (INPE/LAP). Also, a scanning system for the optics of scattered light

  2. 3.5. Apparatus for plasma electron temperature measurement by Thomson scattering

    International Nuclear Information System (INIS)

    Kolacek, K.; Babicky, V.

    1981-01-01

    Equipment was developed and tested for measuring time-resolved local electron plasma temperature and density by the Thomson scattering of ruby laser light. The laser consists of a Q-switched generator (ruby 12 mm in diameter by 150 mm long) followed by one amplifier (ruby 16 mm indi long) followed by one amplifier (ruby 16 mm in diameter by 250 mm long). For Q-switching a Pockels cell with a z-cut ADP crystal was used. The laser is capable of delivering 4 J of energy in a pulse of 50 ns in duration. The spectrum of the laser light scattered at an angle of 9a degrees is analyzed by a six-channel polychromator. Fibre optics and photomultipliers with gated amplifiers are used. Output signals are transmitted via a parallel-to-series converter to a single-trace oscilloscope. The whole Thomson scattering apparatus was successfully tested by the Rayleigh scattering in the air at atmospheric pressure. (J.U.)

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  4. Multi-Point Thomson Scattering Diagnostic for the Helicity Injected Torus

    Science.gov (United States)

    Liptac, J. E.; Smith, R. J.; Hoffman, C. S.; Jarboe, T. R.; Nelson, B. A.; Leblanc, B. P.; Phillips, P.

    1999-11-01

    The multi-point Thomson scattering system on the Helicity Injected Torus--II can determine electron temperature and density at 11 radial positions at a single time during the plasma discharge. The system includes components on loan from both PPPL and from the University of Texas. The collection optics and Littrow spectrometer from Princeton, and the 1 GW laser and multi-anode microchannel plate detector from Texas have been integrated into a compact structure, creating a mobile and reliable diagnostic. The mobility of the system allows alignment to occur in a room adjacent to the experiment, greatly reducing the disturbance to normal machine operation. The four main parts of the Thomson scattering system, namely, the laser, the beam line, the collection optics, and the mobile structure are presented and discussed.

  5. Modeling traveling-wave Thomson scattering using PIConGPU

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander; Schramm, Ulrich; Cowan, Thomas; Bussmann, Michael [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Steiniger, Klaus; Pausch, Richard; Huebl, Axel [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universitaet Dresden (Germany)

    2016-07-01

    Traveling-wave Thomson scattering (TWTS) laser pulses are pulse-front tilted and dispersion corrected beams that enable all-optical free-electron lasers (OFELs) up to the hard X-ray range. Electrons in such a side-scattering geometry experience the TWTS laser field as a continuous plane wave over centimeter to meter interaction lengths. After briefly discussing which OFEL scenarios are currently numerically accessible, we detail implementation and tests of TWTS beams within PIConGPU (3D-PIC code) and show how numerical dispersion and boundary effects are kept under control.

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

    Science.gov (United States)

    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.

  7. First high-repetition-rate Thomson scattering for fusion plasmas

    International Nuclear Information System (INIS)

    Roehr, H.; Steuer, K.H.; Schramm, G.; Hirsch, K.; Salzmann, H.

    1982-01-01

    Electron temperature and density measurements by Thomson scattering were performed for the first time for the whole duration of a tokamak discharge. A Nd:YAG laser of 60 pulses per second at 1.06μm was used in ASDEX in combination with silicon avalanche photodiode detectors. Density calibration was done by rotational anti-Stokes Raman scattering from hydrogen. The system is used for measurements at electron densities as low as 3x10 12 cm -3 . (author)

  8. First 50 pps Thomson scattering diagnostics in a tokamak

    International Nuclear Information System (INIS)

    Roehr, H.; Schramm, G.; Steuer, K.H.; Hirsch, K.; Salzmann, H.

    1981-12-01

    Electron temperature and density measurements by Thomson scattering were performed for the first time for the whole duration of a tokamak discharge. A 50 pps Nd:YAG laser at 1.06 μm was used in ASDEX in combination with Si avalanche photodiode detectors. Density calibration was done by rotational anti-Stokes Raman scattering from hydrogen. The system is used for measurements at electron densities of as low as 2 x 10 12 cm -3 . (orig.)

  9. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    International Nuclear Information System (INIS)

    Farias, G.; Dormido-Canto, S.; Vega, J.; Santos, M.; Pastor, I.; Fingerhuth, S.; Ascencio, J.

    2014-01-01

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process

  10. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Farias, G., E-mail: gonzalo.farias@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informática y Automática, UNED, 28040 Madrid (Spain); Vega, J., E-mail: jesus.vega@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Santos, M., E-mail: msantos@ucm.es [Departamento de Arquitectura de Computadores y Automática, Universidad Complutense de Madrid, 28040 Madrid (Spain); Pastor, I., E-mail: ignacio.pastor@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Fingerhuth, S., E-mail: sebastian.fingerhuth@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Ascencio, J., E-mail: j_ascencio21@hotmail.com [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile)

    2014-05-15

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.

  11. K-α X-ray Thomson Scattering From Dense Plasmas

    International Nuclear Information System (INIS)

    Kritcher, Andrea L.; Neumayer, Paul; Castor, John; Doeppner, Tilo; Landen, Otto L.; Ng, Andrew; Pollaine, Steve; Price, Dwight; Glenzer, Siegfried H.; Falcone, Roger W.; Ja Lee, Hae; Lee, Richard W.; Morse, Edward C.

    2009-01-01

    Spectrally resolved Thomson scattering using ultra-fast K-α 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 1.7x10 23 cm -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.

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

    International Nuclear Information System (INIS)

    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.

    2009-01-01

    Spectrally resolved Thomson scattering using ultra-fast K-α 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 23 cm -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

  13. Generation of Attosecond X-Ray Pulse through Coherent Relativistic Nonlinear Thomson Scattering

    CERN Document Server

    Lee, K; Jeong, Y U; Lee, B C; Park, S H

    2005-01-01

    In contrast to some recent experimental results, which state that the Nonlinear Thomson Scattered (NTS) radiation is incoherent, a coherent condition under which the scattered radiation of an incident laser pulse by a bunch of electrons can be coherently superposed has been investigated. The Coherent Relativistic Nonlinear Thomson Scattered (C-RNTS) radiation makes it possible utilizing the ultra-short pulse nature of NTS radiation with a bunch of electrons, such as plasma or electron beams. A numerical simulation shows that a 25 attosecond X-ray pulse can be generated by irradiating an ultra-intense laser pulse of 4x10(19) W/cm2 on an ultra-thin solid target of 50 nm thickness, which is commercially available. The coherent condition can be easily extended to an electron beam from accelerators. Different from the solid target, much narrower electron beam is required for the generation of an attosecond pulse. Instead, this condition could be applied for the generation of intense Compton scattered X-rays with a...

  14. A Thomson scattering diagnostic to measure fast ion and α-particle distributions in JET

    International Nuclear Information System (INIS)

    Costley, A.E.; Hoekzema, J.A.; Stott, P.E.; Watkins, M.L.

    1988-01-01

    The paper presents the findings of a feasibility investigation into the proposed Thomson scattering diagnostic to measure fast ion and α-particle distributions in JET. A description is given of the motivation for alpha particle diagnostics on JET, followed by a brief survey of possible α-particle diagnostics for JET. The basic principles of the collective Thomson scattering technique are presented, along with its implementation on JET. The expected performance of the system, and other applications of the diagnostic system are also discussed. (U.K.)

  15. Conceptual design of a divertor Thomson scattering diagnostic for NSTX-U

    Energy Technology Data Exchange (ETDEWEB)

    McLean, A. G., E-mail: mclean@fusion.gat.com; Soukhanovskii, V. A.; Allen, S. L. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Carlstrom, T. N. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); LeBlanc, B. P.; Ono, M.; Stratton, B. C. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A conceptual design for a divertor Thomson scattering (DTS) diagnostic has been developed for the NSTX-U device to operate in parallel with the existing multipoint Thomson scattering system. Higher projected peak heat flux in NSTX-U will necessitate application of advanced magnetics geometries and divertor detachment. Interpretation and modeling of these divertor scenarios will depend heavily on local measurement of electron temperature, T{sub e}, and density, n{sub e}, which DTS provides in a passive manner. The DTS design for NSTX-U adopts major elements from the successful DIII-D DTS system including 7-channel polychromators measuring T{sub e} to 0.5 eV. If implemented on NSTX-U, the divertor TS system would provide an invaluable diagnostic for the boundary program to characterize the edge plasma.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Hun, E-mail: leesh81@nfri.re.kr; Lee, J. H. [National Fusion Research Institute, 169-148 Gwahak-ro, Yuseong-gu, Daejeon 34133 (Korea, Republic of); Yamada, I. [National Institute Fusion Science, Toki, Gifu 509-5292 (Japan); Park, Jae Sun [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of)

    2016-11-15

    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 χ{sup 2} 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 χ{sup 2} method. The best results were obtained for 10{sup 3} training cycles and eight nodes in the hidden layer. Our neural network approach shows good agreement with the χ{sup 2} method and performs the calculation twenty times faster.

  17. A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Corvan, D.J., E-mail: dcorvan01@qub.ac.uk; 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 10{sup 20} photons s{sup −1}mm{sup −2}mrad{sup −2} 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above. - Highlights: • How synchrotron radiation can be produced in an all optical setting using laser-plasmas. • Generating high-energy, high-flux gamma ray beams. • Presenting results from a recent NLTS experimental campaign. • Reveal insight into the experimental techniques employed.

  18. Optical design of the TMX Thomson Scattering Diagnostic

    International Nuclear Information System (INIS)

    Frank, A.M.

    1979-01-01

    The Thomson Scattering Diagnostic on TMX was built to measure the electron temperature in the plug. The design was based on the 2XII system built by Tom Simonen. Substantial improvements were realized over the original design, these include: (1) improved sensitivity, (2) simultaneous multiple position sampling, (3) multiple pulse capability, (4) achromatic imaging, (5) vacuum alignment capability, (6) high reliability, and (7) built in calibration and performance monitoring

  19. TV thomson scattering system on JFT-2M

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Shiina, Tomio; Ishige, Yoichi; Dimock, D.

    1995-01-01

    A higher spatial resolution TV Thomson scattering system was constructed on JFT-2M tokamak. This system has been providing complete profiles of Te and ne at a single time during a plasma discharge. New detector system was developed composed of two stages of image intensifier tubes coupled to a CCD. The extinction ratio of image intensifier was improved to 1.4 x 10 7 at least. (author)

  20. Computer data-acquisition and control system for Thomson-scattering measurements

    International Nuclear Information System (INIS)

    Stewart, K.A.; Foskett, R.D.; Kindsfather, R.R.; Lazarus, E.A.; Thomas, C.E.

    1983-03-01

    The Thomson-Scattering Diagnostic System (SCATPAK II) used to measure the electron temperature and density in the Impurity Study Experiment is interfaced to a Perkin-Elmer 8/32 computer that operates under the OS/32 operating system. The calibration, alignment, and operation of this diagnostic are all under computer control. Data acquired from 106 photomultiplier tubes installed on 15 spectrometers are transmitted to the computer by eighteen 12-channel, analog-to-digital integrators along a CAMAC serial highway. With each laser pulse, 212 channels of data are acquired: 106 channels of signal plus background and 106 channels of background only. Extensive use of CAMAC instrumentation enables large amounts of data to be acquired and control processes to be performed in a time-dependent environment. The Thomson-scattering computer system currently operates in three modes: user interaction and control, data acquisition and transmission, and data analysis. This paper discusses the development and implementation of this system as well as data storage and retrieval

  1. Optical Thomson scatter from laser-ablated plumes

    International Nuclear Information System (INIS)

    Delserieys, A.; Khattak, F. Y.; Lewis, C. L. S.; Riley, D.; Pedregosa Gutierrez, J.

    2008-01-01

    We have obtained density and temperature informations on an expanding KrF laser-ablated magnesium plume via optical Thomson scatter with a frequency doubled Nd:YAG laser. The electron temperature was found to decay with the expected T e ∝t -1 dependence. However, we have found the electron density to have a time dependence n e ∝t -4.95 which can be explained by strong recombination processes. We also observed atomic Raman satellites originating from transitions between the different angular momentum levels of the metastable 3 P 0 term in Mg I

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

    Energy Technology Data Exchange (ETDEWEB)

    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. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ross, James Steven [Univ. of California, San Diego, CA (United States)

    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.

  4. Recent development of collective Thomson scattering for magnetically confined fusion plasmas

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Michelsen, Poul; Hansen, S.K.

    2017-01-01

    Here we review recent experimental developments within the field of collective Thomson scattering with a focus on the progress made on the devices TEXTOR and ASDEX Upgrade. We discuss recently discovered possibilities and limitations of the diagnostic technique. Diagnostic applications with respe...

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

    Energy Technology Data Exchange (ETDEWEB)

    Bodner, G. M., E-mail: gbodner@wisc.edu; Bongard, M. W.; Fonck, R. J.; Reusch, J. A.; Rodriguez Sanchez, C.; Schlossberg, D. J. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2016-11-15

    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.

  6. Plasma rotation and ion temperature measurements by collective Thomson scattering at ASDEX Upgrade

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2015-01-01

    We present the first deuterium ion temperature and rotation measurements by collective Thomson scattering at ASDEX Upgrade. The results are in general agreement with boron-based charge exchange recombination spectroscopy measurements and consistent with neoclassical simulations for the plasma sce...... scenario studied here. This demonstration opens the prospect for direct non-perturbative measurements of the properties of the main ion species in the plasma core with applications in plasma transport and confinement studies.......We present the first deuterium ion temperature and rotation measurements by collective Thomson scattering at ASDEX Upgrade. The results are in general agreement with boron-based charge exchange recombination spectroscopy measurements and consistent with neoclassical simulations for the plasma...

  7. A compact new incoherent Thomson scattering diagnostic for low-temperature plasma studies

    Science.gov (United States)

    Vincent, Benjamin; Tsikata, Sedina; Mazouffre, Stéphane; Minea, Tiberiu; Fils, Jérôme

    2018-05-01

    Incoherent Thomson scattering (ITS) has a long history of application for the determination of electron density and temperature in dense fusion plasmas, and in recent years, has been increasingly extended to studies in low-temperature plasma environments. In this work, the design and preliminary implementation of a new, sensitive and uniquely compact ITS platform known as Thomson scattering experiments for low temperature ion sources are described. Measurements have been performed on a hollow cathode plasma source, providing access to electron densities as low as 1016 m‑3 and electron temperatures of a few eV and below. This achievement has been made possible by the implementation of a narrow volume Bragg grating notch filter for the attenuation of stray light, a feature which guarantees compactness and reduced transmission losses in comparison to standard ITS platforms.

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

    Energy Technology Data Exchange (ETDEWEB)

    Biewer, T. M., E-mail: biewertm@ornl.gov; Meitner, S.; Rapp, J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Ray, H.; Shaw, G. [Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2016-11-15

    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 (T{sub e}) and electron density (n{sub e}) 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 T{sub e} ∼ 2 eV and n{sub e} ∼ 1 × 10{sup 19} m{sup −3}. The configuration of the Proto-MPEX TS diagnostic will be described and plans for improvement will be given.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    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 × 10{sup 13} to 4 × 10{sup 14} cm{sup −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.

  10. Experimental characterization of an ultrafast Thomson scattering x-ray source with three-dimensional time and frequency-domain analysis

    Directory of Open Access Journals (Sweden)

    W. J. Brown

    2004-06-01

    Full Text Available We present a detailed comparison of the measured characteristics of Thomson backscattered x rays produced at the Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures facility at Lawrence Livermore National Laboratory to predicted results from a newly developed, fully three-dimensional time and frequency-domain code. 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, perpendicular wave vector components in the laser focus, and the transverse and longitudinal phase spaces of the electron beam are included. Electron beam energy, energy spread, and transverse phase space measurements of the electron beam at the interaction point are presented, and the corresponding predicted x-ray characteristics are determined. In addition, time-integrated measurements of the x rays produced from the interaction are presented and shown to agree well with the simulations.

  11. Time resolved Thomson scattering measurements on a high pressure mercury lamp

    NARCIS (Netherlands)

    Vries, de N.; Zhu, Xiao-Yan; Kieft, E.R.; Mullen, van der J.J.A.M.

    2005-01-01

    Time resolved Thomson scattering (TS) measurements have been performed on an ac driven high pressure mercury lamp. For this high intensity discharge (HID) lamp, TS is coherent and a coherent fitting routine, including rotational Raman calibration, was used to determine ne and Te from the measured

  12. Energy-angle correlation correction algorithm for monochromatic computed tomography based on Thomson scattering X-ray source

    Science.gov (United States)

    Chi, Zhijun; Du, Yingchao; Huang, Wenhui; Tang, Chuanxiang

    2017-12-01

    The necessity for compact and relatively low cost x-ray sources with monochromaticity, continuous tunability of x-ray energy, high spatial coherence, straightforward polarization control, and high brightness has led to the rapid development of Thomson scattering x-ray sources. To meet the requirement of in-situ monochromatic computed tomography (CT) for large-scale and/or high-attenuation materials based on this type of x-ray source, there is an increasing demand for effective algorithms to correct the energy-angle correlation. In this paper, we take advantage of the parametrization of the x-ray attenuation coefficient to resolve this problem. The linear attenuation coefficient of a material can be decomposed into a linear combination of the energy-dependent photoelectric and Compton cross-sections in the keV energy regime without K-edge discontinuities, and the line integrals of the decomposition coefficients of the above two parts can be determined by performing two spectrally different measurements. After that, the line integral of the linear attenuation coefficient of an imaging object at a certain interested energy can be derived through the above parametrization formula, and monochromatic CT can be reconstructed at this energy using traditional reconstruction methods, e.g., filtered back projection or algebraic reconstruction technique. Not only can monochromatic CT be realized, but also the distributions of the effective atomic number and electron density of the imaging object can be retrieved at the expense of dual-energy CT scan. Simulation results validate our proposal and will be shown in this paper. Our results will further expand the scope of application for Thomson scattering x-ray sources.

  13. Preliminary project of s Thomson scattering system for the ETE tokamak; Projeto preliminar de um sistema de espalhamento Thomson para o Tokamak ETE

    Energy Technology Data Exchange (ETDEWEB)

    Berni, Luiz Angelo

    1997-12-31

    This report presents the preliminary project of the injection and laser light block system for the Thomson (ET) scattering diagnostic to be implanted at the ETE spheric tokamak of the Instituto Nacional de Pesquisas Espaciais (INPE/LAP). Also, a scanning system for the optics of scattered light 4 refs., 26 figs.

  14. Operation of the NSTX Thomson Scattering System

    International Nuclear Information System (INIS)

    LeBlanc, B.P.; Bell, R.E.; Johnson, D.W.; Hoffman, D.E.; Long, D.C.; Palladino, R.W.

    2002-01-01

    The NSTX multi-point Thomson scattering system has been in operation for nearly two years and provides routine Te(R,t) and ne(R,t) measurements. The laser beams from two 30-Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optics bundles. In the present configuration, the output ends of 20 of these bundles are instrumented with filter polychromators and avalanche photodiode detectors. In this paper, we discuss the laser implementation and the installed collection optics. We follow with examples of raw and analyzed data. We close with some comments about calibration

  15. Mirror System for Collecting Thomson-Scattered Light in a Tangential Direction

    NARCIS (Netherlands)

    Barth, C. J.; Grobben, B. J. J.; Verhaag, G. C. H. M.

    1994-01-01

    We describe an optical system for collecting Thomson-scattering light in the tangential direction of a tokamak. The key part of the optics is a set of mirrors arranged as a Venetian blind. This system makes it possible to look around the corner of the tokamak vessel. Design considerations and test

  16. Edge Thomson scattering on RFX-mod

    International Nuclear Information System (INIS)

    Alfier, A.; Pasqualotto, R.

    2006-01-01

    Electron temperature and density profiles of the RFX-mod experiment are characterized by edge gradients typically steeper than the flatter central region. The main Thomson scattering (TS) diagnostic which measures 84-point profiles along a diameter is mainly devoted to cover the core region. A second TS system has been developed to measure 12-point profiles in the external region 0.8< r/a<1, with a spatial resolution of 1 cm. It uses a single shot ruby laser. Input and collection optics share the same vacuum port and they are mounted on one optical bench, which allows offline aligning the system before connecting it to the vessel. The scattered signal is collected by a row of 12 fibers, while 4 fibers on the sides are used to check the alignment and measure the plasma light. The fibers, arranged in a 4x4 pattern, are fed into a four channel filter spectrometer and the spectrum is detected by a GaAs intensified charge-coupled device camera. The filters are arranged in a zigzag geometry, such that only one detector is needed

  17. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Bindslev, H.; Nielsen, S.K.; Porte, L.

    2006-01-01

    Here we present the first measurements by collective Thomson scattering of the evolution of fast-ion populations in a magnetically confined fusion plasma. 150 kW and 110 Ghz radiation from a gyrotron were scattered in the TEXTOR tokamak plasma with energetic ions generated by neutral beam injection...... and ion cyclotron resonance heating. The temporal behavior of the spatially resolved fast-ion velocity distribution is inferred from the received scattered radiation. The fast-ion dynamics at sawteeth and the slowdown after switch off of auxiliary heating is resolved in time. The latter is shown...

  18. Thomson scattering in the EXTRAP-T2 reversed-field pinch

    International Nuclear Information System (INIS)

    Welander, A.

    1996-11-01

    A Thomson scattering system has been installed on the EXTRAP-T2 RFP experiment. The system measures the electron density and temperature in three radial points using three spectral channels. A description of the system, the calibration techniques and examples of data obtained are given. The error bars for the electron temperature measurements are estimated to be < 10% for typical T2-plasmas. 4 refs

  19. Thomson scattering measurements on the high beta pinch Extrap-T1

    International Nuclear Information System (INIS)

    Karlsson, P.

    1989-11-01

    Electron temperature and density measurement on a high beta discharge in the Extrap-T1 device have been performed with Thomson scattering. It was found that the signal levels were low and the plasma background radiation high. The spread of the measured temperatures and densities was large. A computer code was developed to investigate whether this spread in measured temperatures was due to shot to shot variations or to photon statistics. The code showed that the scattered data could be explained by photon statistics

  20. The SPARC-LAB Thomson source

    International Nuclear Information System (INIS)

    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.

    2016-01-01

    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.

  1. The SPARC-LAB Thomson source

    Energy Technology Data Exchange (ETDEWEB)

    Vaccarezza, C., E-mail: cristina.vaccarezza@lnf.infn.it [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Alesini, D.; Anania, M.P. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Bacci, A. [INFN-MI, Via Celoria 16, 20133 Milan (Italy); Biagioni, A.; Bisesto, F.; Bellaveglia, M. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Cardarelli, P. [University of Ferrara and INFN-FE, via Saragat 1, 44122 Ferrara (Italy); Cardelli, F. [University La Sapienza and INFN-Roma1, Piazzale Aldo Moro, 2 00161 Rome (Italy); Cianchi, A. [University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Chiadroni, E.; Croia, M.; Curcio, A. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Delogu, P. [University of Pisa and INFN-PI, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Giovenale, D. Di [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Domenico, G. Di [University of Ferrara and INFN-FE, via Saragat 1, 44122 Ferrara (Italy); Pirro, G. Di [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Drebot, I. [INFN-MI, Via Celoria 16, 20133 Milan (Italy); Ferrario, M. [INFN-LNF, Via Enrico Fermi, 40 00044 Frascati, Rome (Italy); Filippi, F. [University La Sapienza and INFN-Roma1, Piazzale Aldo Moro, 2 00161 Rome (Italy); and others

    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.

  2. The spectrometer of the High-Resolution Multi position Thomson Scattering Diagnostic for TJ-II

    International Nuclear Information System (INIS)

    Herranz, J.; Barth, C. J.; Castejon, F.; Lopez-Sanchez, A.; Mirones, E.; Pastor, I.; Perez, D.; Rodriguez, C.

    2001-01-01

    Since 1998, a high-resolution multiposition thompson scattering system is in operation at the stellarator TJ-II, combining high accuracy and excellent spatial resolution. A description of the diagnostic spectrometer is presented. The main characteristics of the spectrometer that allow YJ-II Thomson scattering diagnostic to have high spatial and spectral resolution are described in this paper. (Author)

  3. The Thomson scattering system at Wendelstein 7-X

    Science.gov (United States)

    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.

  4. Thomson scattering upgrade on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, F., E-mail: fabrice.leroux@cea.f [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Manenc, L.; Moreau, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2010-07-15

    The Thomson scattering diagnostic supplies the electron temperature and density of Tore Supra plasmas from the spectrum analysis of scattered light of a very short laser pulse. A new spectrometer has been realized to improve the signal to noise ratio. In order to obtain an efficient noise reduction, a real time calculation is necessary. The current analogue integration of the signal is inadequate. A fast digitalization must be used with a sampling rate of 1 GSamples/s, a bandwidth of 150 MHz and a 12 bits dynamic range. In a first step, fast analogue data acquisition boards for 4 channels were added in 2009 to the VME acquisition system in place. A MATACQ (Matrix for acquisition) board was chosen for sampling analogue data up to 2 GSamples/s over 4 channels with a large bandwidth of 300 MHz and a 14 bits dynamic range. This solution offers a low cost acquisition system that is not available in any other commercial board with this dynamic range. The first results will be obtained on calibration period with a light emitted diode before the summer 2009. This article will present the new data acquisition system and the coming first results.

  5. Movable Thomson scattering system based on optical fiber (TS-probe)

    International Nuclear Information System (INIS)

    Narihara, K.; Hayashi, H.

    2009-01-01

    This paper proposes a movable compact Thomson scattering (TS) system based on optical fibers (TS-probe). A TS-probe consists of a probe head, optical fiber, a laser-diode, polychromators and lock-in amplifiers. A laser beam optics and light collection optics are mounted rigidly on a probe head with a fixed scattering position. Laser light and scattered light are transmitted by flexible optical fibers, enabling us to move the TS-prove head freely during plasma discharge. The light signal scattered from an amplitude-modulated laser is detected against the plasma light based on the principle of the lock-in amplifier. With a modulated laser power of 300W, the scattered signal from a sheet plasma of 15 mm depth and n e -10 19 m -3 will be measured with 10% accuracy by setting the integrating time to 0.1 s. The TS-probe head is like a 1/20 model of the currently operating LHD-TS. (author)

  6. A compact multichannel spectrometer for Thomson scattering

    International Nuclear Information System (INIS)

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

    2012-01-01

    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 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.

  7. A compact multichannel spectrometer for Thomson scattering.

    Science.gov (United States)

    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) 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.

  8. Modelling Thomson scattering for systems with non-equilibrium electron distributions

    Directory of Open Access Journals (Sweden)

    Chapman D.A.

    2013-11-01

    Full Text Available We investigate the effect of non-equilibrium electron distributions in the analysis of Thomson scattering for a range of conditions of interest to inertial confinement fusion experiments. Firstly, a generalised one-component model based on quantum statistical theory is given in the random phase approximation (RPA. The Chihara expression for electron-ion plasmas is then adapted to include the new non-equilibrium electron physics. The theoretical scattering spectra for both diffuse and dense plasmas in which non-equilibrium electron distributions are expected to arise are considered. We find that such distributions strongly influence the spectra and are hence an important consideration for accurately determining the plasma conditions.

  9. Subterahertz gyrotron developments for collective Thomson scattering in LHDa)

    Science.gov (United States)

    Notake, T.; Saito, T.; Tatematsu, Y.; Kubo, S.; Shimozuma, T.; Tanaka, K.; Nishiura, M.; Fujii, A.; Agusu, La; Ogawa, I.; Idehara, T.

    2008-10-01

    Collective Thomson scattering (CTS) is expected to provide the spatially resolved velocity distribution functions of not only thermal and tail ions but also alpha particles resulting from fusion reactions. CTS using gyrotrons with frequency higher than the conventional ones used for plasma heating would have advantages to alleviate refraction, cutoff effects, and background electron cyclotron emission noise. Therefore, a high-power pulse gyrotron operating at approximately 400 GHz is being developed for CTS in Large Helical Device (LHD). A single-mode oscillation with a frequency greater than 400 GHz, applying the second-harmonic resonance, was successfully demonstrated in the first stage. At the same time, concrete feasibility study based on ray tracing, scattering spectra, and electron cyclotron emission calculations has been conducted.

  10. Examination of a duo-collection optics design for the Korea superconducting tokamak advanced research (KSTAR) Thomson scattering system

    International Nuclear Information System (INIS)

    Oh, Seungtae; Lee, Jong Ha

    2011-01-01

    The comparison of collective optic designs is described for the Thomson scattering system of the Korea superconducting tokamak advanced research (KSTAR) device. The optical systems collecting the light emission induced through the interaction between the plasma electrons and a laser beam are the key components for the Thomson scattering system. In the first conceptual design of the collection optics for the KSTAR Thomson scattering system, a duo-lens system covering individually the core and the edge regions of the KSTAR plasma with two optical lens modules was proposed. In optical designs, the number of optical modules is a great concern in the case of limited system space. Here, the duo-lens system is evaluated through a comparison with a uni-lens system covering the whole region of the plasma with a single optical module. The duo-lens system turned out to have 2.0 times and 4.73 times higher light collections of the plasma core and edge compared with the uni-lens system

  11. Evaluation of the optical design of laser Thomson scattering diagnostics for high-temperature EAST tokamak and low-temperature MAP-II divertor simulator

    International Nuclear Information System (INIS)

    Kado, Shinichiro; Scotti, Filippo; Xi Xiaoqi; Zhao Junyu

    2009-01-01

    The optical design of the laser Thomson scattering (LTS) system for EAST tokamak is now on-going. Based on the Visible YAG laser TVTS system developed in the MAP-II (material and plasma) steady-state linear divertor/edge plasma simulator at the University of Tokyo, the required specification and the applicability of the VIS-YAG-TVTS system was evaluated in terms of the photon number to be collected by the fiber light-guide to a spectrometer and the reciprocal linear dispersion of the spectrometer. Then, the possible design of the optical system was proposed. (author)

  12. Progress on Thomson scattering in the Pegasus Toroidal Experiment

    International Nuclear Information System (INIS)

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

    2013-01-01

    A novel Thomson scattering system has been implemented on the Pegasus Toroidal Experiment where typical densities of 10 19 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 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

  13. Progress on Thomson scattering in the Pegasus Toroidal Experiment

    Science.gov (United States)

    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 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.

  14. TFTR 60 GHz alpha particle collective Thomson Scattering diagnostic

    International Nuclear Information System (INIS)

    Machuzak, J.S.; Woskov, P.P.; Gilmore, J.; Bretz, N.L.; Park, H.K.; 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

  15. Testing ion structure models with x-ray Thomson scattering

    Directory of Open Access Journals (Sweden)

    Wünsch K.

    2013-11-01

    Full Text Available We investigate the influence of various ionic structure models on the interpretation of the X-ray Thomson scattering signal. For the calculation of the ion structure, classical hypernetted chain equations are used applying different effective inter-particle potentials. It is shown that the different models lead to significant discrepancies in the theoretically predicted weight of the Rayleigh peak, in particular for small k-values where correlation effects are important. Here, we propose conditions which might allow for an experimental verification of the theories under consideration of experimental constraints of k-vector blurring.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

    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

  17. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2014-11-15

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

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

    Energy Technology Data Exchange (ETDEWEB)

    Brookman, M. W., E-mail: brookmanmw@fusion.gat.com [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Austin, M. E.; McLean, A. G. [Lawrence Livermore National Lab, Livermore, California 94500 (United States); Carlstrom, T. N.; Hyatt, A. W.; Lohr, J. [General Atomics, San Diego, California 92122 (United States)

    2016-11-15

    Thomson scattering produces n{sub e} profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation n{sub e} ∝ I{sub TS}, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the n{sub e} calibration is adjusted against an absolute n{sub e} 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 n{sub e} 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.

  19. Optical design for divertor Thomson scattering system for JT-60SA

    International Nuclear Information System (INIS)

    Kajita, Shin; Enokuchi, Akito; Hatae, Takaki; Itami, Kiyoshi; Hamano, Takashi; Kado, Shinichiro; Ohno, Noriyasu; Takeyama, Norihide

    2014-01-01

    Highlights: •A detailed designing for collection optical system of divertor Thomson scattering system in JT-60SA is conducted. •The assessment of the density and temperature errors of the measurement system is conducted. •It is shown that the measurement could be done with the temperature error of 50% when the density was 10 20 m −3 . •The availability of the laser transmission mirrors for the measurement system is discussed. •Several guidelines to improve the measurement system are discussed. -- Abstract: Optical design for divertor Thomson scattering system in JT-60SA has been conducted. The measurement system will use a Nd:YAG laser at 1064 nm, and scattered photons are collected by a collection optical system. The collection optics consists of primary mirror, secondary mirror, relay optics, and fiber collection optics. The laser transmission mirror and collection optics were designed to be installed in a slender lower port of JT-60SA. The assessment of the measurement errors in temperature was conducted for the designed collection optical system. Because of spatial limitation, the solid angle from the measurement points would be small especially for the measurement points in high field side, and consequently, the temperature errors in the high field side would be considerably large. The effects of several improvements on the error are discussed. Moreover, an assessment for the in-vessel laser transmission metallic mirrors is conducted for the present design

  20. New develops in Thomson scattering diagnostics on the L-2 stellarator

    International Nuclear Information System (INIS)

    Blokh, M.A.; Larionova, N.F.

    1989-01-01

    In this paper, a multichannel plasma diagnostic system employing Thomson scattering is modernized for the L-2 stellarator. A specialized polychromator with a large field of view, high contrast, and transmission is used together with a 16-channel photoelectron recorder. The modernized system makes it possible to measure the electron temperature at three points simultaneously in the plasma column cross-section at a local electron density 3.10 12 cm-3

  1. Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

    DEFF Research Database (Denmark)

    Salewski, Mirko; Meo, Fernando; Stejner Pedersen, Morten

    2010-01-01

    Collective Thomson scattering (CTS) experiments were carried out at ASDEX Upgrade to measure the one-dimensional velocity distribution functions of fast ion populations. These measurements are compared with simulations using the codes TRANSP/NUBEAM and ASCOT for two different neutral beam injecti...

  2. Design of new Thomson scattering diagnostic system on COMPASS tokamak

    Czech Academy of Sciences Publication Activity Database

    Bílková, Petra; Aftanas, Milan; Böhm, Petr; Weinzettl, Vladimír; Šesták, David; Melich, Radek; Stöckel, Jan; Scannell, R.; Walsh, M.

    2010-01-01

    Roč. 623, č. 2 (2010), s. 656-659 ISSN 0168-9002. [International Conference on Frontiers in Diagnostic Technologies/1st./. Frascati, 25.11.2009-27.11.2009] R&D Projects: GA ČR GA202/09/1467; GA ČR GD202/08/H057 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thomson scattering * Laser diagnostic * Electron temperature * Electron density Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.142, year: 2010 www.elsevier.com/locate/nima

  3. Impact of beam ions on α-particle measurements by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.; Budny, R.V.

    2005-01-01

    Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask the measureme......Collective Thomson scattering (CTS) has been proposed as a viable diagnostic for characterizing fusion born a-distributions in ITER. However, the velocities of the planned 1 MeV deuterium heating beam ions in 1TER are similar to that of fusion born a-particles and may therefore mask...... and the alpha-particles are calculated. Our investigations show that the CTS measurements of alpha-particles will not be masked by the presence of the beam ions in H-mode plasmas. In lower density reversed shear plasmas, only a part of the CTS alpha-particle spectrum will be perturbed....

  4. Laser Thomson Scattering, Raman Scattering and laser-absorption diagnostics of high pressure microdischarges

    International Nuclear Information System (INIS)

    Donnelly, Vincent M; Belostotskiy, Sergey G; Economou, Demetre J; Sadeghi, Nader

    2010-01-01

    Laser scattering experiments were performed in high pressure (100s of Torr) parallel-plate, slot-type DC microdischarges operating in argon or nitrogen. Laser Thomson Scattering (LTS) and Rotational Raman Scattering were employed in a novel, backscattering, confocal configuration. LTS allows direct and simultaneous measurement of both electron density (n e ) and electron temperature (T e ). For 50 mA current and over the pressure range of 300 - 700 Torr, LTS yielded T e = 0.9 ± 0.3 eV and n e = (6 ± 3)·10 13 cm -3 , in reasonable agreement with the predictions of a mathematical model. Rotational Raman spectroscopy (RRS) was employed for absolute calibration of the LTS signal. RRS was also applied to measure the 3D gas temperature (T g ) in nitrogen DC microdischarges. In addition, diode laser absorption spectroscopy was employed to measure the density of argon metastables (1s5 in Paschen notations) in argon microdischarges. The gas temperature, extracted from the width of the absorption profile, was compared with T g values obtained by optical emission spectroscopy.

  5. A compact multichannel spectrometer for Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbeck, N. L.; Schlossberg, D. J.; Dowd, A. S.; Fonck, R. J.; Winz, G. R. [Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    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.

  6. Digital filter polychromator for Thomson scattering applications

    Science.gov (United States)

    Solokha, V.; Kurskiev, G.; Mukhin, E.; Tolstyakov, S.; Babinov, N.; Bazhenov, A.; Bukreev, I.; Dmitriev, A.; Kochergin, M.; Koval, A.; Litvinov, A.; Masyukevich, S.; Razdobarin, A.; Samsonov, D.; Semenov, V.; Solovey, V.; Chernakov, P.; Chernakov, Al; Chernakov, An

    2018-02-01

    Incoherent Thomson scattering diagnostics (TS) is a proven technique capable of reliable and robust instantaneous measurement of electron temperature (T e) and density (n e) local values in wide area of plasma physics experiments: from hall-effect thrusters to tokamaks and stellarators. The TS cross section is very low (˜ 6.7 × 10-30 m2), and the corresponding TS signals, measured in fusion experiments, are usually of ˜10-15 of incident power. This paper represents 6 (7) channel filter polychromator equipped with avalanche photodiodes and low-noise preamplifiers. The incorporated ADC system (5 GS/s, 12 bit) provides digital optical output preventing acquisition system from electromagnetic interferences. The calibration techniques and T e, n e with corresponding errors measured in Globus-M plasma are given for the digital polychromator test-bench.

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

    Science.gov (United States)

    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.

  8. Thomson scattering on COMPASS – commissioning and first data

    Czech Academy of Sciences Publication Activity Database

    Aftanas, Milan; Böhm, Petr; Scannell, R.; Tripsky, M.; Weinzettl, Vladimír; Hron, Martin; Pánek, Radomír; Stöckel, Jan; Walsh, M.; Bílková, Petra

    2012-01-01

    Roč. 7, č. 1 (2012), C01074-C01074 ISSN 1748-0221. [INTERNATIONAL CONFERENCE ON LASER AIDED PLASMA DIAGNOSTICS/15./. Jeju, 13.10.2011-19.10.2011] R&D Projects: GA ČR GA202/09/1467 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thomson scattering * electron temperature * laser diagnostic * Plasma diagnostics - charged-particle spectroscopy * Plasma diagnostics - interferometry * spectroscopy and imaging * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.869, year: 2011 http://iopscience.iop.org/1748-0221/7/01/C01074/pdf/1748-0221_7_01_C01074.pdf

  9. Collective Thomson scattering measurements with high frequency resolution at TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Korsholm, Søren Bang

    2010-01-01

    We discuss the development and first results of a receiver system for the collective Thomson scattering (CTS) diagnostic at TEXTOR with frequency resolution in the megahertz range or better. The improved frequency resolution expands the diagnostic range and utility of CTS measurements in general ...... and is a prerequisite for measurements of ion Bernstein wave signatures in CTS spectra. The first results from the new acquisition system are shown to be consistent with theory and with simultaneous measurements by the standard receiver system. © 2010 EURATOM...

  10. THE THOMSON SURFACE. I. REALITY AND MYTH

    International Nuclear Information System (INIS)

    Howard, T. A.; DeForest, C. E.

    2012-01-01

    The solar corona and heliosphere are visible via sunlight that is Thomson-scattered off free electrons and detected by coronagraphs and heliospheric imagers. It is well known that these instruments are most responsive to material at the 'Thomson surface', the sphere with a diameter passing through both the observer and the Sun. It is less well known that in fact the Thomson scattering efficiency is minimized on the Thomson surface. Unpolarized heliospheric imagers such as STEREO/HI are thus approximately equally responsive to material over more than a 90° range of solar exit angles at each given position in the image plane. We call this range of angles the 'Thomson plateau'. We observe that heliospheric imagers are actually more sensitive to material far from the Thomson surface than close to it, at a fixed radius from the Sun. We review the theory of Thomson scattering as applied to heliospheric imaging, feature detection in the presence of background noise, geometry inference, and feature mass measurement. We show that feature detection is primarily limited by observing geometry and field of view, that the highest sensitivity for detection of density features is to objects close to the observer, that electron surface density inference is independent of geometry across the Thomson plateau, and that mass inference varies with observer distance in all geometries. We demonstrate the sensitivity results with a few examples of features detected by STEREO, far from the Thomson surface.

  11. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD

    DEFF Research Database (Denmark)

    Kubo, S.; Nishiura, M.; Tanaka, K.

    2010-01-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power ECRH system in 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 ...

  12. Study of a CW, two-dimensional Thomson scattering diagnostic system

    International Nuclear Information System (INIS)

    Hsieh, C.L.; Bray, B.D.; Liu, C.

    2004-01-01

    We describe an approach to Thomson scattering diagnostic that relies upon a high power CW laser cavity and a rf signal detection technique, instead of the more usual pulsed high energy laser. The system has three major elements: an ultra long (∼150 m) laser resonance cavity that includes the plasma region; an array of CW diode lasers of high power and high modulation frequency that pumps and maintains the average cavity energy (∼10 mJ); and a lock-in detection system of narrow frequency bandwidth (∼2 kHz). The resonance cavity consists of a pumping chamber for power input from diode lasers, and many relay chambers (∼30) distributed across the plasma cross section for Thomson measurement. The cavity has a low energy loss (∼2% round trip) and zero output power. It is estimated that signal-to-noise of the system is ∼100 times better than the present pulsed system on DIII-D Tokamak due to the increase in usable laser energy and the improved background signal rejection

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

    DEFF Research Database (Denmark)

    Leipold, Frank; Furtula, Vedran; Salewski, Mirko

    2009-01-01

    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...

  14. A Concept for Measuring Electron Distribution Functions Using Collective Thomson Scattering

    Science.gov (United States)

    Milder, A. L.; Froula, D. H.

    2017-10-01

    A.B. Langdon proposed that stable non-Maxwellian distribution functions are realized in coronal inertial confinement fusion plasmas via inverse bremsstrahlung heating. For Zvosc2 Zvosc2 vth2 > 1 , vth2 > 1 , the inverse bremsstrahlung heating rate is sufficiently fast to compete with electron-electron collisions. This process preferentially heats the subthermal electrons leading to super-Gaussian distribution functions. A method to identify the super-Gaussian order of the distribution functions in these plasmas using collective Thomson scattering will be proposed. By measuring the collective Thomson spectra over a range of angles the density, temperature and super-Gaussian order can be determined. This is accomplished by fitting non-Maxwellian distribution data with a super-Gaussian model; in order to match the density and electron temperature to within 10%, the super-Gaussian order must be varied. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  15. Design of practical alignment device in KSTAR Thomson diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. H., E-mail: jhlee@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); University of Science and Technology (UST), Daejeon (Korea, Republic of); Lee, S. H. [National Fusion Research Institute, Daejeon (Korea, Republic of); Yamada, I. [National Institute for Fusion Science, Toki (Japan)

    2016-11-15

    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.

  16. Theory of Thomson scattering in a strong magnetic field, 2. [Relativistic quantum theory, cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, T [Ibaraki Univ., Mito (Japan). Dept. of Physics

    1975-07-01

    A relativistic quantum theory is formulated for the Compton scattering by electrons in a strong magnetic field. It is shown that the relativistic quantum (Klein-Nishina) cross section in the center of drift system reduces exactly to the classical Thomson cross section in the limit h..omega../2..pi..<Thomson cross section is valid irrespective of the magnitudes of ..omega.. and ..omega..sub(c); the forward scattering in the direction of the magnetic field by an electron in the ground state.

  17. Collective Thomson scattering data analysis for Wendelstein 7-X

    DEFF Research Database (Denmark)

    Abramovic, I.; Pavone, A.; Svensson, J.

    2017-01-01

    Collective Thomson scattering (CTS) diagnostic is being installed on the Wendelstein 7-X stellarator to measure the bulk ion temperature in the upcoming experimental campaign. In order to prepare for the data analysis, a forward model of the diagnostic (eCTS) has been developed and integrated...... into the Bayesian data analysis framework Minerva. Synthetic spectra have been calculated with the forward model and inverted using Minerva in order to demonstrate the feasibility to measure the ion temperature in the presence of nuisance parameters that also influence CTS spectra. In this paper we report...... on the results of this anlysis and discuss the main sources of uncertainty in the CTS data analysis....

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

    International Nuclear Information System (INIS)

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

    1997-01-01

    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

  19. Plasma turbulence imaging using high-power laser Thomson scattering

    Science.gov (United States)

    Zweben, S. J.; Caird, J.; Davis, W.; Johnson, D. W.; Le Blanc, B. P.

    2001-01-01

    The two-dimensional (2D) structure of plasma density turbulence in a magnetically confined plasma can potentially be measured using a Thomson scattering system made from components of the Nova laser of Lawrence Livermore National Laboratory. For a plasma such as the National Spherical Torus Experiment at the Princeton Plasma Physics Laboratory, the laser would form an ≈10-cm-wide plane sheet beam passing vertically through the chamber across the magnetic field. The scattered light would be imaged by a charge coupled device camera viewing along the direction of the magnetic field. The laser energy required to make 2D images of density turbulence is in the range 1-3 kJ, which can potentially be obtained from a set of frequency-doubled Nd:glass amplifiers with diameters in the range of 208-315 mm. A laser pulse width of ⩽100 ns would be short enough to capture the highest frequency components of the expected density fluctuations.

  20. 154 GHz collective Thomson scattering in LHD

    Science.gov (United States)

    Tanaka, K.; Nishiura, M.; Kubo, S.; Shimozuma, T.; Saito, T.; Moseev, D.; Abramovic, I.

    2018-01-01

    Collective Thomson scattering (CTS) was developed by using a 154 GHz gyrotron, and the first data has been obtained. Already, 77 GHz CTS has worked successfully. However, in order to access higher density region, 154 GHz option enhances the usability that reduces the refraction effect, which deteriorates in the local measurements. The system in the down converted frequency was almost identical to the system for 77 GHz. Probing beam, a notch filter, a mixer, and a local oscillator in the receiver system for 77 GHz option were replaced to those for the 154 GHz option. 154 GHz gyrotron was originally prepared for the second harmonic electron cyclotron heating (ECRH) at 2.75 T. However, scattering signal was masked by the second harmonic electron cyclotron emission (ECE) at 2.75 T. Therefore, 154 GHz CTS was operated at 1.375 T with fourth harmonic ECE, and an acceptable signal to noise ratio was obtained. There is a signature of fast ion components with neutral beam (NB) injection. In addition, the CTS spectrum became broader in hydrogen discharge than in deuterium discharge, as the theoretical CTS spectrum expects. This observation indicates a possibility to identify ion species ratio by the 154 GHz CTS diagnostic.

  1. Improvements to the MST Thomson Scattering Diagnostic

    Science.gov (United States)

    Adams, D. T.; Borchardt, M. T.; den Hartog, D. J.; Holly, D. J.; Kile, T.; Kubala, S. Z.; Jacobson, C. M.; Thomas, M. A.; Wallace, J. P.; Young, W. C.; MST Thomson Scattering Team

    2017-10-01

    Multiple upgrades to the MST Thomson Scattering diagnostic have been implemented to expand capabilities of the system. In the past, stray laser light prevented electron density measurements everywhere and temperature measurements for -z/a >0.75. To mitigate stray light, a new laser beamline is being commissioned that includes a longer entrance flight tube, close-fitting apertures, and baffles. A polarizer has been added to the collection optics to further reduce stray light. An absolute density calibration using Rayleigh scattering in argon will be performed. An insertable integrating sphere will provide a full-system spectral calibration as well as maps optical fibers to machine coordinates. Reduced transmission of the collection optics due to coatings from plasma-surface interactions is regularly monitored to inform timely replacements of the first lens. Long-wavelength filters have been installed to better characterize non-Maxwellian electron distribution features. Previous work has identified residual photons not described by a Maxwellian distribution during m =0 magnetic bursts. Further effort to characterize the distribution function will be described. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences program under Award No. DE-FC02-05ER54814.

  2. Measurements of ion temperature and plasma hydrogenic composition by collective Thomson scattering in neutral beam heated discharges at TEXTOR

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Salewski, Mirko; Korsholm, Søren Bang

    2013-01-01

    A method is developed to perform plasma composition and ion temperature measurements across the plasma minor radius in TEXTOR based on ion cyclotron structures in collective Thomson scattering spectra. By gradually moving the scattering volume, we obtain measurements across the outer midplane of ...

  3. The Thomson scattering experiment pulsed by CO2 laser in FT

    International Nuclear Information System (INIS)

    Bartolini, L.; Fornetti, G.; Nardi, M.; Occhionero, G.; Ferri de Collibus, M.

    1987-01-01

    An experiment carried out to measure the plasma ion temperature Tsub(i) in the tokamak FT in Frascati by Collective Thomson Scattering. A tandem laser system generates two single mode beams (10.6μ) one of which is pulsed and amplified up to levels of 5 MW, 1μs and actively frequency locked to a second continuous wave low pressure CO 2 laser. The pulse beam crosses the plasma and the forward scattered light is collected at angles between 1 degrees centigrade and 1.6 degrees centigrade. An heterodyne technique in which the c.w. beam is the local oscillator is used to measure the Doppler enlarged spectral density of the signal. The experimental apparatus is described and the results are reported and discussed

  4. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Meo, Fernando; Korsholm, Søren Bang

    In this report we investigate the feasibility of diagnosing the fast ions in ITER by collective Thomson scattering (CTS), exploring and comparing the diagnostic potentials of CTS systems base on a range of different probe frequencies. In the first section we first recall the requirements for meas...... the diagnostic potentials uncovered in the preceding four sections. A number of more detailed discussions are placed in appendices along with supporting material....... for measurements of the confined fusion alpha particles in ITER set by the ITER team. Then we outline the considerations, which enter into the selection and evaluation of CTS systems. System definition includes choice of probe frequency, geometry of probe and receiver beam patterns and probe power, but ultimately...... covers many more details. Here we introduce terms and methods used in the more detailed system evaluations later in the report. In Sections 2 through 5 we consider four different types of CTS systems, which differ by the ranges in which their probe frequencies lie. In Section 6 we summarize and compare...

  5. Time-resolved Thomson scattering on high-intensity laser-produced hot dense helium plasmas

    International Nuclear Information System (INIS)

    Sperling, P; Liseykina, T; Bauer, D; Redmer, R

    2013-01-01

    The introduction of brilliant free-electron lasers enables new pump–probe experiments to characterize warm and hot dense matter states, i.e. systems at solid-like densities and temperatures of one to several hundred eV. Such extreme conditions are relevant for high-energy density studies such as, e.g., in planetary physics and inertial confinement fusion. We consider here a liquid helium jet pumped with a high-intensity optical short-pulse laser that is subsequently probed with brilliant soft x-ray radiation. The optical short-pulse laser generates a strongly inhomogeneous helium plasma which is characterized with particle-in-cell simulations. We derive the respective Thomson 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 observe plasmon modes that are generated in the interior of the target and study their temporal evolution. Such pump–probe experiments are promising tools to measure the important plasma parameters density and temperature. The method described here can be applied to various pump–probe scenarios by combining optical lasers, soft x-rays and hard x-ray sources. (paper)

  6. Dynamics of fast ions during sawtooth oscillations in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Salewski, Mirko; Bindslev, Henrik

    2011-01-01

    Experimental investigations of sawteeth interaction with fast ions measured by collective Thomson scattering on TEXTOR are presented. Time-resolved measurements of localized 1D fast-ion distribution functions allow us to study fast-ion dynamics during several sawtooth cycles. Sawtooth oscillation...

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

    Czech Academy of Sciences Publication Activity Database

    Böhm, Petr; Aftanas, Milan; Bílková, Petra; Štefániková, Estera; Mikulín, Ondřej; Melich, Radek; Janky, Filip; Havlíček, Josef; Šesták, David; Weinzettl, Vladimír; Stöckel, Jan; Hron, Martin; Pánek, Radomír; Scannell, R.; Frassinetti, L.; Fassina, A.; Naylor, G.; Walsh, M.J.

    2014-01-01

    Roč. 85, č. 11 (2014), 11E431-11E431 ISSN 0034-6748. [Topical Conference on High-Temperature Plasma Diagnostics/20./. Atlanta, Georgia, 01.06.2014-05.06.2014] R&D Projects: GA MŠk(CZ) LM2011021; GA ČR(CZ) GA14-35260S Institutional support: RVO:61389021 Keywords : plasma * tokamak * pedestal * Thomson scattering * diagnostic Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.614, year: 2014 http://scitation.aip.org/content/aip/journal/rsi/85/11/10.1063/1.4893995

  8. Multipoint Thomson scattering system for the EXTRAP Z-pinch experiment

    International Nuclear Information System (INIS)

    Karlsson, P.

    1986-03-01

    A Thomson scattering system for simultaneous measurements of the electron temperature and density at three different positions at two different times during a single plasma shot has been developed for the EXTRAP-L1 Z-pinch. The plasma in the present version of EXTRAP-L1 is characterized by densities in the range from 10 21 to 10 22 m -3 , temperatures up to 50 eV and a pinch radius of the order of 1 cm. A spatial resolution down to 3 mm between positions is obtained by imaging the plasma onto an array of quartz optical fibres at the output slit of the spectrometer. Fifteen PM-tubes are used to detect the scattered radiation as well as the background radiation. Due to the relatively dense plasma prevailing in the present version of EXTRAP-L1 the number of scattered photons in large and the photon to electron conversion noise is small. The background radiation is the most important factor limiting the accuracy of the measurements. (author)

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

    DEFF Research Database (Denmark)

    Bin, W.; Bruschi, A.; D'Arcangelo, O.

    2015-01-01

    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 i...

  10. Design of the divertor Thomson scattering system on DIII-D

    International Nuclear Information System (INIS)

    Carlstrom, T.N.; Foote, J.H.; Nilson, D.G.; Rice, B.W.

    1994-05-01

    Local measurements of n e and T e in the divertor region are necessary for a more complete understanding of divertor physics. We have designed an extension to the existing multipulse Thomson scattering system to measure n e in the range 5 x 10 18 to 5 x 10 20 m -3 and T e 5--500 eV, with 1 cm resolution from 1--21 cm above the floor of the DIII-D vessel, in the region of the X-point for lower single-null diverted plasmas. One of the existing 8, 20 Hz, ND:YAG lasers will be redirected to a separate vertical port, and viewed radially with a specially designed, f/6.8 lens. Fiber optics carry the light to additional polychromators whose interference filters have been optimized for low T e measurements. Other aspect of the system, including the beam path to the vessel, polychromator design, real time data acquisition, laser control, calibration facility, and DIII-D timing and data acquisition interface will be shared with the existing multipulse Thomson system. An in-situ laser alignment monitor will provide alignment information for each laser pulse

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Study of TJ-1 Tokamak plasmas with Thomson scattering and radiation diagnostics

    International Nuclear Information System (INIS)

    Pardo, C.; Zurro, B.

    1987-06-01

    The Thomson scattering system of TJ-1 is described in detail. The radial profiles of T e and n e obtained in TJ-1 discharges are presented. This data makes possible to deduce characteristic parameters of the plasma confinement in this machine, as energy confinement times, Z eff B. Using also radiation measurements (global and in the visible range) we obtained the particle confinement time and Z eff without non experimental assumptions. (author) 56 figs., 52 refs

  13. A 130 point Nd:YAG Thomson scattering diagnostic on MAST

    Energy Technology Data Exchange (ETDEWEB)

    Scannell, R.; Walsh, M. J.; Dunstan, M. R.; Figueiredo, J.; Naylor, G.; O' Gorman, T.; Shibaev, S. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Gibson, K. J.; Wilson, H. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2010-10-15

    A Thomson scattering diagnostic designed to measure both edge and core physics has been implemented on MAST. The system uses eight Nd:YAG lasers, each with a repetition rate of 30 Hz. The relative and absolute timing of the lasers may be set arbitrarily to produce fast bursts of measurements to suit the time evolution of the physics being studied. The scattered light is collected at F/6 by a 100 kg six element lens system with an aperture stop of 290 mm. The collected light is then transferred to 130 polychromators by 130 independent fiber bundles. The data acquisition and processing are based on a distributed computer system of dual core processors embedded in 26 chassis. Each chassis is standalone and performs data acquisition and processing for five polychromators. This system allows data to be available quickly after the MAST shot and has potential for real-time operations.

  14. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    International Nuclear Information System (INIS)

    Moseev, D.

    2011-11-01

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  15. Fast ion dynamics in ASDEX upgrade and TEXTOR measured by collective Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Moseev, D.

    2011-11-15

    Fast ions are an essential ingredient in burning nuclear fusion plasmas: they are responsible for heating the bulk plasma, carry a significant amount of plasma current and moreover interact with various magnetohydrodynamic (MHD) instabilities. The collective Thomson scattering (CTS) diagnostic is sensitive to the projection of fast ion velocity distribution function. This thesis is mainly devoted to investigations of fast ion physics in tokamak plasmas by means of CTS. (Author)

  16. Fast-ion redistribution due to sawtooth crash in the TEXTOR tokamak measured by collective Thomson scattering

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Salewski, Mirko

    2010-01-01

    Here we present collective Thomson scattering measurements of 1D fast-ion velocity distribution functions in neutral beam heated TEXTOR plasmas with sawtooth oscillations. Up to 50% of the fast ions in the centre are redistributed as a consequence of a sawtooth crash. We resolve various directions...

  17. Preliminary application of maximum likelihood method in HL-2A Thomson scattering system

    International Nuclear Information System (INIS)

    Yao Ke; Huang Yuan; Feng Zhen; Liu Chunhua; Li Enping; Nie Lin

    2010-01-01

    Maximum likelihood method to process the data of HL-2A Thomson scattering system is presented. Using mathematical statistics, this method maximizes the possibility of the likeness between the theoretical data and the observed data, so that we could get more accurate result. It has been proved to be applicable in comparison with that of the ratios method, and some of the drawbacks in ratios method do not exist in this new one. (authors)

  18. Progress on the multipulse Thomson scattering diagnostic on DIII-D

    International Nuclear Information System (INIS)

    Stockdale, R.E.; Carlstrom, T.N.; Hsieh, C.L.; Makariou, C.C.

    1995-01-01

    The DIII-D Thomson scattering diagnostic, operational since 1990, uses 8 Nd:YAG 20-Hz lasers to measure electron temperature and density profiles (40 spatial points) throughout the plasma discharge. Recent progress has enabled a new set of operating modes to better fulfill varying plasma physics requirements. Custom circuitry for laser control (programmable with 1 μs precision) has successfully replaced a previous scheme which used real-time 68030 software. Two new modes of operation have been demonstrated. Burst mode is useful to study a transient plasma event: a series of laser pulses are fired at a rate ≤10 kHz after an external asynchronous event trigger. Burst mode is also useful to synchronize the Thomson lasers with other systems, such as an asynchronous Michelson ECE diagnostic scanning near 40 Hz. Group mode allows a programmed set of lasers to fire simultaneously into the same (65 ns) data acquisition gate. Improved signal/noise then yields smaller statistical errors in the profile results. This provides profile data for lower density plasmas, such as those anticipated during fast wave current drive experiments. Plans for a new CCD-based laser alignment system for position monitoring and feedback control will also be presented

  19. Enhanced Thomson scattering theory applied to eight experiments

    International Nuclear Information System (INIS)

    Simon, A.; Short, R.W.; Seka, W.; Goldman, L.M.

    1985-01-01

    The onset of an instability, such as the 2ω/sub p/ at the n/sub c//4 surface, usually leads to wave breaking and the emission of hot electron pulses which can profoundly influence instability thresholds and scattering behavior elsewhere in the plasma. In particular, enhanced Thomson scattering (via the plasma line) can occur, and this has been used to explain the observation of the SRS instability well below the theoretical threshold. A simple model of the hot electron pulses based on measured values of the hot and cold electron temperatures, T/sub h/ and T/sub c/, has yielded good agreement with experimental observation of the Raman spectral frequency bands. The agreement has continued, even for experiments which are clearly above the SRS threshold, with the enhanced noise likely acting as a ''seed'' for the SRS growth. We will show details of the successful comparison of this theory with six experiments carried out on SHIVA, ARGUS, NOVETTE(2), and GDL(2), and also with an upscattering feature seen at Garching. In addition, a recent experiment using 6 beams of OMEGA (at 0.35μ) will be discussed, and compared with the theory. The report is comprised of viewgraphs of the talks

  20. Te and ne profiles on JFT-2M plasma with the highest spatial resolution TV Thomson scattering system

    International Nuclear Information System (INIS)

    Yamauchi, T.

    1993-01-01

    A high spatial resolution TV Thomson scattering system was constructed on JFT-2M tokamak. This system is similar to those used at PBX-M and TFTR. These systems are providing complete profiles of Te and ne at a single time during a plasma discharge. The characteristics of JFT-2M TVTS are as follows: 1. Measured points are composed of not only 81 points for the scattered light and plasma light, whose time difference is 2 ms, but also 10 points for plasma light measured at the same time with scattered light. 2. Spatial resolution is 0.86 cm, which is higher than any other Thomson scattering system. 3. Sensitivity of detector composed of image intensifier tubes and CCD is as high as that of photomultiplier tube. Te and ne profiles have been measured over one year on JFT-2M. The line-averaged electron density measured was in the region of 5x10 12 cm -3 - 7x10 13 cm -3 and the measured electron temperature was in the region of 50 eV -1.2 keV. (author) 7 refs., 7 figs., 1 tab

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

    Science.gov (United States)

    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. A multi-laser system for a fast sampling Thomson scattering diagnostic

    International Nuclear Information System (INIS)

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

    1990-10-01

    A multi-laser system is being developed for the DIII-D Thomson scattering diagnostic. This system combines the beams from up to eight Nd:YAG lasers onto a common beamline in which the beams are nearly parallel and are all focused into a small, common area within the desired scattering volume. Each laser can be fired at a constant rate (20 Hz per laser) for a high average repetition rate, or together in a ''burst,'' which will give very high sampling rates (10--20 kHz) for short periods. The burst mode will be triggerable by plasma events, which will allow for study of transient phenomena, but will require non-periodic firing of the lasers. Beamline diagnostics include position sensitive detectors for computer controlled feedback alignment of the 35 m beamline, an image position detection system for monitoring the alignment of the collection lens to the scattering volume, and a 1-D reticon camera for divergence monitoring. The effects of the non-periodic firing of the lasers will be monitored with the reticon camera. 3 refs., 5 figs

  3. An energy confinement study of the MST [Madison Symmetric Torus] reversed field pinch using a Thomson scattering diagnostic

    International Nuclear Information System (INIS)

    Den Hartog, D.J.

    1989-11-01

    Thomson scattering measurements of the central electron temperature and density during the plasma current peak have been performed on the MST Reversed Field Pinch (RFP). This Thomson scattering diagnostic was calibrated for absolute electron density measurements. These measurements of T e and n e , when combined with profile assumptions, were used to calculate estimates of energy confinement time (τ E ) and poloidal beta (β θ ). A standard discharge with I p ∼ 400 kA, F ∼ -0.1, and θ ∼ 1.6 typically exhibited T e ∼ 275 eV, n e ∼ 2.0 x 10 13 cm -3 , τ E ≤ 1 ms, and β θ ≤ 8%. The results of a limited plasma current scaling study did not indicate a strong scaling of T e or τ E with I p . The Thomson scattering diagnostic was used in conjunction with a bolometer, VUV radiation monitor, and edge magnetic coils to study the loss of energy from the plasma. Results indicate that thermal transport from stochastic magnetic fields, particle loss, and radiation are important energy loss processes. The experiments done for this study included an F-scan, a paddle limiter insertion series, and an argon doping series. The plasma maintained a constant βτ during these perturbation experiments, suggesting that increases in one energy loss channel are compensated by drops in other channels and increases in input power to the plasma

  4. Design of a Thomson scattering diagnostic system for VEST

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Gi [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Jong Ha [National Fusion Research Institute, Gwahangno 113, Daejeon 305-333 (Korea, Republic of); Lee, Jeongwon; An, YoungHwa; Dang, Jeong Jeung; Jo, Jungmin; Lee, HyunYeong; Chung, Kyoung-Jae; Hwang, Y.S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Na, Yong-Su, E-mail: ysna@snu.ac.kr [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2015-10-15

    Highlights: • A Thomson scattering system for Versatile Experiment Spherical Torus is designed. • The system is designed with care for the plasma with a low target electron density. • APD of low dark current and enhanced sensitivity for near infrared has been chosen. • A collecting optics system will provide a sufficient number of photoelectrons. • A designed polychromator is able to measure the electron temperature of 10–1000 eV. - Abstract: A Thomson scattering diagnostic system is designed for Versatile Experiment Spherical Torus (VEST) to measure the spatial profiles of the electron temperature. The system is carefully designed to collect a sufficient number of photoelectrons and to reduce the noise sources, since relatively low electron densities and temperatures are expected in VEST due to the limited power capacity at present. The target electron temperature and the density are 10–200 eV and 5 × 10{sup 18} m{sup −3}, respectively which are extrapolated from the data of triple Langmuir probes measuring the edge plasma parameters at R = 0.75 m by assuming a parabolic density profile. The collecting optics is designed to have a wide-view angle and low cost by using a commercial photographic lens of low f-number and high transmittance optical fiber bundle. The bandwidths of the interference filters in the polychromator are designed for reliable measurements within the target electron temperature range. As a photo detector which is coupled with the filters, an avalanche photodiode (APD) with a low dark current and an adequate quantum efficiency near the laser wavelength is selected for the high signal-to-noise ratio. The number of photons transferred to the polychromator and the number of photoelectrons in the APD are calculated. At the commissioning phase, an oscilloscope with a high sampling rate will be adopted to check the necessity of the noise reduction by multi-shot signal accumulation.

  5. Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Nielsen, Stefan Kragh; Bindslev, Henrik

    2011-01-01

    ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced......For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio—i.e. the tritium to deuterium density...... by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio...

  6. Hβ Stark broadening in cold plasmas with low electron densities calibrated with Thomson scattering

    International Nuclear Information System (INIS)

    Palomares, J.M.; Hübner, S.; Carbone, E.A.D.; Vries, N. de; Veldhuizen, E.M. de; Sola, A.; Gamero, A.; Mullen, J.J.A.M. van der

    2012-01-01

    In the present work Stark broadening measurements have been carried out on low electron density (n e 19 m −3 ) and (relatively) low gas temperature (T g e . - Highlights: ► Stark broadening measurements at low density and temperature conditions ► Calibration with Thomson scattering ► Indications of the non-Lorentzian shape of the Stark broadening ► Impossibility of simultaneous diagnostic of gas temperature and electron density

  7. Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

    Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

  8. Measurements of plasma composition in the TEXTOR tokamak by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

    2012-01-01

    We demonstrate the use of collective Thomson scattering (CTS) for spatially localized measurements of the isotopic composition of magnetically confined fusion plasmas. The experiments were conducted in the TEXTOR tokamak by scattering millimeter-wave probe radiation off plasma fluctuations...... with wave vector components nearly perpendicular to the magnetic field. Under such conditions the sensitivity of the CTS spectrum to plasma composition is enhanced by the spectral signatures of the ion cyclotron motion and of weakly damped ion Bernstein waves. Recent experiments on TEXTOR demonstrated...... the ability to resolve these signatures in the CTS spectrum as well as their sensitivity to the ion species mix in the plasma. This paper shows that the plasma composition can be inferred from the measurements through forward modeling of the CTS spectrum. We demonstrate that spectra measured in plasmas...

  9. Experimental and simulated fast ion velocity distributions on collective Thomson scattering diagnostic in the Large Helical Device

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2012-01-01

    We have developed a collective Thomson scattering diagnostic system in the LHD. The CTS spectrum spread is observed in the frequency region corresponding to the bulk and fast ions during NB injection. The NB originated fast ions are evaluated by the MORH code for understanding the measured CTS sp...

  10. Alignment of the Thomson scattering diagnostic on NSTX

    International Nuclear Information System (INIS)

    LeBlanc, B P; Diallo, A

    2013-01-01

    The Thomson scattering diagnostic can provide profile measurement of the electron temperature, T e , and density, n e , in plasmas. Proper laser beam path and optics arrangement permits profiles T e (R) and n e (R) measurement along the major radius R. Keeping proper alignment between the laser beam path and the collection optics is necessary for an accurate determination of the electron density. As time progresses the relative position of the collection optics field of view with respect to the laser beam path will invariably shift. This can be kept to a minimum by proper attention to the physical arrangement of the collection and laser-beam delivery optics. A system has been in place to monitor the relative position between laser beam and collection optics. Variation of the alignment can be detected before it begins to affect the quality of the profile data. This paper discusses details of the instrumentation and techniques used to maintain alignment during NSTX multi-month experimental campaigns

  11. Development of high-efficiency laser Thomson scattering measurement system for the investigation of EEDF in surface wave plasma

    International Nuclear Information System (INIS)

    Aramaki, M.; Kobayashi, J.; Kono, A.; Stamate, E.; Sugai, H.

    2006-01-01

    A high-efficiency multichannel Thomson scattering measurement system was developed as a tool for studying the electron heating mechanisms in a surface wave plasma. By improving the output power and repetition rate of the Nd:YAG laser, an F-number of spectrograph, and a quantum efficiency of ICCD camera, the overall Thomson signal collection efficiency per unit measurement time has been improved by a factor larger than 40 in comparison with the previous measurement system developed by the authors. The one-dimensional electron velocity distribution functions were measured in the vicinity of the dielectric window of a surface wave plasma

  12. Diagnostic of the Symbiotic Stars Environment by Thomson, Raman and Rayleigh Scattering Processes

    Directory of Open Access Journals (Sweden)

    M. Sekeráš

    2015-02-01

    Full Text Available Symbiotic stars are long-period interacting binaries consisting of a cool giant as the donor star and a white dwarf as the acretor. Due to acretion of the material from the giant’s stellar wind, the white dwarf becomes very hot and luminous. The circumstellar material partially ionized by the hot star, represents an ideal medium for processes of scattering. To investigate the symbiotic nebula we modeled the wide wings of the resonance lines OVI λ1032 Å, λ1038 Å and HeII λ1640 Å emission line in the spectrum of AG Dra, broadened by Thomson scattering. On the other hand, Raman and Rayleigh scattering arise in the neutral part of the circumstellar matter around the giant and provide a powerful tool to probe e.g. the ionization structure of the symbiotic systems and distribution of the neutral hydrogen atoms in the giant’s wind.

  13. Prospects for ion temperature measurements in JET by Thomson scattering of submillimetre waves

    International Nuclear Information System (INIS)

    Whitbourn, L.B.

    1975-03-01

    The Thomson scattering of submillimeter waves is envisaged as a possible means for measuring the ion temperature of the JET plasma. The present discussion is principally concerned with the practical limitations imposed to the method by the availability of high power pulsed sources and sensitive detectors and noise due to plasma emission at submillimeter wavelengths (bremsstrahlung and electron cyclotron emission). Coherent scattering from plasma wave (e.g. ion acoustic waves and electron drift waves) with millimeter and submillimeter waves are considered briefly. Further suitable development of lasers and heterodyne detectors would make such measurements possible. A pulsed HCN laser associated with a detectors with a lower heterodyne noise equivalent power could then be used to advantage. For scattering with CH 3 F laser the NEP of a Josephson junction would be adequate because a relatively high level of plasma emission is expected at 496 μm [fr

  14. The data acquisition and control system for Thomson Scattering on ATF [Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Stewart, K.A.; Kindsfather, R.R.; Rasmussen, D.A.

    1989-01-01

    The 2-dimensional Thomson Scattering System measuring electron temperatures and densities in the Advanced Toroidal Facility (ATF) is interfaced to a VAX-8700 computer system running in a clustered configuration. Calibration, alignment, and operation of this diagnostic is under computer control. Extensive CAMAC instrumentation is used for timing control, data acquisition, and laser alignment. This paper will discuss the computer hardware and software, system operations, and data storage and retrieval. 3 refs

  15. Detailed modeling of the statistical uncertainty of Thomson scattering measurements

    International Nuclear Information System (INIS)

    Morton, L A; Parke, E; Hartog, D J Den

    2013-01-01

    The uncertainty of electron density and temperature fluctuation measurements is determined by statistical uncertainty introduced by multiple noise sources. In order to quantify these uncertainties precisely, a simple but comprehensive model was made of the noise sources in the MST Thomson scattering system and of the resulting variance in the integrated scattered signals. The model agrees well with experimental and simulated results. The signal uncertainties are then used by our existing Bayesian analysis routine to find the most likely electron temperature and density, with confidence intervals. In the model, photonic noise from scattered light and plasma background light is multiplied by the noise enhancement factor (F) of the avalanche photodiode (APD). Electronic noise from the amplifier and digitizer is added. The amplifier response function shapes the signal and induces correlation in the noise. The data analysis routine fits a characteristic pulse to the digitized signals from the amplifier, giving the integrated scattered signals. A finite digitization rate loses information and can cause numerical integration error. We find a formula for the variance of the scattered signals in terms of the background and pulse amplitudes, and three calibration constants. The constants are measured easily under operating conditions, resulting in accurate estimation of the scattered signals' uncertainty. We measure F ≈ 3 for our APDs, in agreement with other measurements for similar APDs. This value is wavelength-independent, simplifying analysis. The correlated noise we observe is reproduced well using a Gaussian response function. Numerical integration error can be made negligible by using an interpolated characteristic pulse, allowing digitization rates as low as the detector bandwidth. The effect of background noise is also determined

  16. Using X-ray Thomson Scattering to Characterize Highly Compressed, Near-Degenerate Plasmas at the NIF

    Science.gov (United States)

    Doeppner, Tilo; Kraus, D.; Neumayer, P.; Bachmann, B.; Divol, L.; Kritcher, A. L.; Landen, O. L.; Fletcher, L.; Glenzer, S. H.; Falcone, R. W.; MacDonald, M. J.; Saunders, A.; Witte, B.; Redmer, R.; Chapman, D.; Baggott, R.; Gericke, D. O.; Yi, S. A.

    2017-10-01

    We are developing x-ray Thomson scattering for implosion experiments at the National Ignition Facility to characterize plasma conditions in plastic and beryllium capsules near stagnation, reaching more than 20x compression and electron densities of 1025 cm-3, corresponding to a Fermi energy of 170 eV. Using a zinc He- α x-ray source at 9 keV, experiments at a large scattering angle of 120° measure non-collective scattering spectra with high sensitivity to K-shell ionization, and find higher charge states than predicted by widely used ionization models. Reducing the scattering angle to 30° probes the collective scattering regime with sensitivity to collisions and conductivity. We will discuss recent results and future plans. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. Timing and triggering of the Thomson scattering diagnostics on the COMPASS tokamak

    Czech Academy of Sciences Publication Activity Database

    Mikulín, Ondřej; Hron, Martin; Böhm, Petr; Naylor, G.; Bílková, Petra; Janky, Filip; Salášek, J.; Pánek, Radomír

    2014-01-01

    Roč. 89, č. 5 (2014), s. 693-697 ISSN 0920-3796. [The 9th Technical Meeting on Control, Data Acquisition, and Remote Participation for Fusion Research/9./. Hefei, 06.05.2013-10.05.2013] R&D Projects: GA MŠk 7G10072; GA MŠk(CZ) LM2011021; GA ČR GAP205/11/2470 Institutional support: RVO:61389021 Keywords : Tokamak * Timing and triggering * FPGA * Real-time control * Diagnostics control * Thomson scattering Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.152, year: 2014 http://www.sciencedirect.com/science/article/pii/S0920379614002105#

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  19. LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

    2009-06-01

    Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

  20. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

    International Nuclear Information System (INIS)

    Bindslev, H; Nielsen, S K; Porte, L; Hoekzema, J A; Korsholm, S B; Meo, F; Michelsen, P K; Michelsen, S; Oosterbeek, J W; Tsakadze, E L; Westerhof, E; Woskov, P

    2007-01-01

    The dynamics of fast ion populations in the TEXTOR tokamak are measured by collective Thomson scattering of millimetre wave radiation generated by a gyrotron operated at 110 GHz and 100-150 kW. Temporal evolution of the energetic ion velocity distribution at switch on of neutral beam injection (NBI) and the slowdown after switch off of NBI are measured. The turn on phase of the NBI has, furthermore, been measured in plasmas with a range of electron densities and temperatures. All of these measurements are shown to be in good agreement with simple Fokker-Planck modelling. Bulk ion rotation velocity is also measured

  1. Measurement of electron density of the plasma in the Tokamak TCABR, through Thomson scattering diagnostic

    International Nuclear Information System (INIS)

    Jeronimo, Leonardo Cunha

    2013-01-01

    Over the last few years is remarkable, so increasingly evident the need for a new source of energy for mankind. One promising option is through nuclear fusion, where the plasma produced in the reactor can be converted into electrical energy. Therefore, knowing the characteristics of this plasma is very important to control it and understand it so desirable. One of the diagnostic options is called Thomson scattering . This is considered the most reliable method for the determination of important plasma parameters such as temperature and electron density, and may also help in the study and explanation of various internal mechanisms. The great advantage lies in the tact that they consist of a direct measurement and nonperturbative. But it is a diagnosis whose installation and execution is admittedly complex, limiting it only a few laboratories in the fíeld of fusion for the world. Among the main difficulties, wc can highlight the fact that the scattered signal is very small, thus requiring a large increase of the incident power. Moreover, the external physical conditions can cause mechanical vibrations that eliminate or minimize them as much as possible, is a great challenge, considering the optical micrometrically very sensitive and needs involved in the system. This work describes the entire process of installation and operation of Thomson scattering diagnostic in tokamak TCABR and through this diagnosis, we work on results of electron temperature, to finally be able to calculate the electron density of the plasma. (author)

  2. Improvement of the bandwidth of the transient digitizers in the LIDAR Thomson scattering diagnostic on JET

    International Nuclear Information System (INIS)

    Kristensen, E.

    1990-06-01

    The main limitation on the spatial resolution of the LIDAR Thomson scattering diagnostic on the JET tokamak is due to the narrow bandwidth of the detection system. The transient digitizers, Tektronik 7912AD, are the main contributors to the narrow bandwidth. It is shown how the digitizers can be modified to improve the response time from approx. 480 to 410 ps. (author)

  3. Focusing effects in laser-electron Thomson scattering

    Directory of Open Access Journals (Sweden)

    Chris Harvey

    2016-09-01

    Full Text Available 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.

  4. Personnel protection during the operation of Thomson scattering laser system on COMPASS tokamak

    Czech Academy of Sciences Publication Activity Database

    Böhm, Petr; Hron, Martin; Kovar, J.; Sova, J.; Zvolanek, M.; Aftanas, Milan; Bílková, Petra; Pánek, Radomír; Walsh, M.J.

    2011-01-01

    Roč. 86, 6-8 (2011), s. 699-702 ISSN 0920-3796. [Symposium on Fusion Technology, SOFT-26/26th./. Porto, 27.09.2010-01.10.2010] R&D Projects: GA ČR GA202/09/1467; GA ČR GD202/08/H057; GA MŠk 7G09042 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * Thomson scattering * Laser safety * Personnel protection * PLC Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.490, year: 2011 http://www.sciencedirect.com/science/article/pii/S0920379611002432

  5. Development of high-spatial resolution TV Thomson scattering system for JFT-2M

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Shiina, Tomio; Kozawa, Teruo; Ishige, Youichi.

    1996-01-01

    The JFT-2M TV Thomson scattering system (TVTS) with high spatial resolution was completed in the cooperation of the fusion research and development for the DOE-JAERI collaborative program, and has been operated for 3 years. The system is composed of six subsystems; vacuum components, optics, detector, control and data acquisition, software and laser subsystems. TVTS was totally tested in the JFT-2M tokamak and the electron temperature and density profiles are measured with good reproducibility, and the increase of electron temperature by increasing toroidal magnetic field is also measured with TVTS. (author)

  6. Calculation of the nonlinear relativistic Thomson scattering fields and Its application to electron distribution function diagnostic

    Science.gov (United States)

    Guasp, J.; Pastor, I.; Álvarez-Estrada, R. F.; Castejón, F.

    2015-02-01

    Analytical results obtained recently of the ab-initio classical incoherent Thomson Scattering (TS) spectrum from a single-electron (Alvarez-Estrada et al 2012 Phys. Plasmas 19 062302) have been numerically implemented in a paralelized code to efficiently compute the TS emission from a given electron distribution function, irrespective of its characteristics and/or the intensity of the incoming radiation. These analytical results display certain differences, when compared with other authors, in the general case of incoming linearly and circularly polarized radiation and electrons with arbitrary initial directions. We regard such discrepancies and the ubiquitous interest in TS as motivations for this work. Here, we implement some analytical advances (like generalized Bessel functions for incoming linearly polarized radiation) in TS. The bulk of this work reports on the efficient computation of TS spectra (based upon our analytical approach), for an electron population having an essentially arbitrary distribution function and for both incoming linearly and circularly polarized radiation. A detailed comparison between the present approach and a previous Monte Carlo one (Pastor et al 2011 Nuclear Fusion 51 043011), dealing with the ab-initio computation of TS spectra, is reported. Both approaches are shown to fully agree with each other. As key computational improvements, the analytical technique yields a × 30 to × 100 gain in computation time and is a very flexible tool to compute the scattered spectrum and eventually the scattered electromagnetic fields in the time domain. The latter are computed explicitly here for the first time, as far as we know. Scaling laws for the power integrated over frequency versus initial kinetic energy are studied for the case of isotropic and monoenergetic electron distribution functions and their potential application as diagnostic tools for high-energy populations is briefly discussed. Finally, we discuss the application of these

  7. Possibilities for direct optical observation of negative hydrogen ions in ion beam plasma sources via Rayleigh or Thomson scattering

    International Nuclear Information System (INIS)

    Burgess, D.D.

    1985-01-01

    The possibilities of applying optical scattering techniques to the determination of H - concentrations in plasma sources relevant to negative ion beam generation are considered. Rayleigh scattering measurements for incident wavelengths just below the H - photoionization limit appear to be only just feasible experimentally. A more promising possibility is observation of the modification in a plasma containing negative ions of the collective ion-feature in Thomson scattering. Numerical predictions of the effects of H - concentration on the spectral distribution of the ion-feature are presented. (author)

  8. Feasibility of alpha particle measurement in a magnetically confined plasma by CO2 laser Thomson scattering

    International Nuclear Information System (INIS)

    Richards, R.K.; Vander Sluis, K.L.; Hutchinson, D.P.

    1987-08-01

    Fusion-product alpha particles will dominate the behavior of the next generation of ignited D-T fusion reactors. Advanced diagnostics will be required to characterize the energy deposition of these fast alpha particles in the magnetically confined plasma. For small-angle coherent Thomson scattering of a CO 2 laser beam from such a plasma, a resonance in the scattered power occurs near 90 0 with respect to the magnetic field direction. This spatial concentration permits a simplified detection of the scattered laser power from the plasma using a heterodyne system. The signal produced by the presence of fusion-product alpha particles in an ignited plasma is calculated to be well above the noise level, which results from statistical variations of the background signal produced by scattering from free electrons. 7 refs

  9. Thomson scattering on ELMO Bumpy Torus

    International Nuclear Information System (INIS)

    Cobble, J.A.

    1985-04-01

    Below 10 12 cm -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 11 cm -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 12 cm -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

  10. X-Ray Thomson Scattering Without the Chihara Decomposition

    Science.gov (United States)

    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.

  11. X-ray Thomson Scattering from Spherically Imploded ICF Ablators

    Science.gov (United States)

    Kritcher, Andrea; Doeppner, Tilo; Landen, Otto; Glenzer, Siegfried

    2010-11-01

    Time-resolved X-ray Thomson scattering measurements from spherically imploded inertial fusion capsules-type targets have been obtained for the first time at the Omega OMEGA laser facility to characterize the in-flight properties of ICF ablators. In these experiments, the non-collective, or microscopic particle behavior, of imploding CH and Be shells, was probed using a 9 keV Zn He-alpha x-ray source at scattering angles of 113^o and 135^o. for two drive pulse shapes.As an example, the analysis of In-flight scattering measurements from one set of directly-driven compressed 8600 μm-diameter, 40-μm thick Be shells taken (4.2 ns after the start of the compression beamswhen compressed a factor of 4.83x) yielded electron densities of ˜ 1.2±0.23x10^24cm-3, temperatures of ˜13±32 eV, and an ionization state of Be(+2), with uncertainties in the temperature and density of about 40% and 20%. These conditions resulting in an inferred adiabat (ratio of plasma pressure to Fermi degenerate pressure) of 1.797 +0.3/-.5 with an error of about 30%. The high signal-to-noise and high signal-to-background ratio of data obtained in these experiments provides a platform for studying the adiabat of other indirect-drive ICF ablators such as CH and High Density Carbon (HDC) ablators and demonstrates the viability of using this diagnostic to study the in-flight properties adiabat of implosion targets at the National Ignition Facility (NIF).

  12. Operation of ADITYA Thomson scattering system: measurement of temperature and density

    International Nuclear Information System (INIS)

    Thomas, Jinto; Pillai, Vishal; Singh, Neha; Patel, Kiran; Lingeshwari, G.; Hingrajiya, Zalak; Kumar, Ajai

    2015-01-01

    ADITYA Thomson scattering (TS) system is a single point measurement system operated using a 10 J ruby laser and a 1 meter grating spectrometer. Multi-slit optical fibers are arranged at the image plane of the spectrometer so that each fiber slit collects 2 nm band of scattered spectrum. Each slit of the fiber bundle is coupled to high gain Photomultiplier tubes (PMT). Standard white light source is used to calibrate the optical fiber transmission and the laser light itself is used to calibrate the relative gain of the PMT. Rayleigh scattering has been performed for the absolute calibration of the TS system. The temperature of ADITYA plasma has been calculated using the conventional method of estimation (calculated using the slope of logarithmic intensity vs the square of delta lambda). It has been observed that the core temperature of ADITYA Tokamak plasma is in the range of 300 to 600 eV for different plasma shots and the density 2-3 X 10 13 /cc. The time evolution of the plasma discharge has been studied by firing the laser at different times of the discharge assuming the shots are identical. In some of the discharges, the velocity distribution appears to be non Maxwellian. (author)

  13. Single-shot Thomson scattering on argon plasmas created by the Microwave Plasma Torch; evidence for a new plasma class

    NARCIS (Netherlands)

    Mullen, van der J.J.A.M.; Sande, van de M.J.; Vries, de N.; Broks, B.H.P.; Iordanova, E.I.; Gamero, A.; Torres, J.; Sola, A.

    2007-01-01

    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

  14. GPIB based instrumentation and control system for ADITYA Thomson Scattering Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kiran, E-mail: kkpatel@ipr.res.in; Pillai, Vishal; Singh, Neha; Chaudhary, Vishnu; Thomas, Jinto; Kumar, Ajai

    2016-11-15

    The ADITYA Thomson Scattering Diagnostic is a single point Ruby laser based system with a spectrometer for spectral dispersion and photomultiplier tubes for the detection of scattered light. The system uses CAMAC (Computer Automated Measurement And Control) based control and data acquisition system, which synchronizes the Ruby laser, detectors and the digitizer. Previously used serial based CAMAC controller is upgraded to GPIB (General Purpose Interface Bus) based CAMAC controller for configuration and data transfer. The communication protocols for different instruments are converted to a single GPIB based for better interface. The entire control and data acquisition program is developed on LabVIEW platform for versatile operation of diagnostics with improved user friendly GUI (Graphical User Interfaces) and allows user to remotely update the laser firing time with respect to the plasma shot. The software is in handshake with the Tokamak main control program through network to minimize manual interventions for the operation of the diagnostics. The upgraded system improved the performance of the diagnostics in comparison to earlier in terms of better data transmission rate, easy to maintain and program is upgradable.

  15. GPIB based instrumentation and control system for ADITYA Thomson Scattering Diagnostic

    International Nuclear Information System (INIS)

    Patel, Kiran; Pillai, Vishal; Singh, Neha; Chaudhary, Vishnu; Thomas, Jinto; Kumar, Ajai

    2016-01-01

    The ADITYA Thomson Scattering Diagnostic is a single point Ruby laser based system with a spectrometer for spectral dispersion and photomultiplier tubes for the detection of scattered light. The system uses CAMAC (Computer Automated Measurement And Control) based control and data acquisition system, which synchronizes the Ruby laser, detectors and the digitizer. Previously used serial based CAMAC controller is upgraded to GPIB (General Purpose Interface Bus) based CAMAC controller for configuration and data transfer. The communication protocols for different instruments are converted to a single GPIB based for better interface. The entire control and data acquisition program is developed on LabVIEW platform for versatile operation of diagnostics with improved user friendly GUI (Graphical User Interfaces) and allows user to remotely update the laser firing time with respect to the plasma shot. The software is in handshake with the Tokamak main control program through network to minimize manual interventions for the operation of the diagnostics. The upgraded system improved the performance of the diagnostics in comparison to earlier in terms of better data transmission rate, easy to maintain and program is upgradable.

  16. Initial results of the high resolution edge Thomson scattering upgrade at DIII-D.

    Science.gov (United States)

    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.

  17. Feasability study of using the TFTR Thomson scattering system for q profile measurements

    International Nuclear Information System (INIS)

    Brizard, A.; Grewk, B.; Johnson, D.; LeBlanc, B.

    1986-01-01

    The results of a study made to determine the possibility of using the TFTR 76 channels Thomson scattering system to measure the direction of local magnetic fields in a tokamak plasma are presented. As this is a local measurement, this technique can in principle yield q profiles without the need of any de-convolution. The effect of the TFTR geometrical configuration and its various components on the expected measurement accuracy is discussed. The authors find that the measurement of q values within the inner half of the plasma should be possible, with only minor modification to the present TVTS system

  18. Experimental considerations concerning the velocity measurement of the relativistic electron beam in a gyrotron by means of Thomson scattering

    International Nuclear Information System (INIS)

    Siegrist, M.R.; Soumagne, G.; Tran, M.Q.

    1992-11-01

    The feasibility of Thomson scattering to determine the beam velocity in a gyrotron has been analyzed and preliminary experiments to implement such a system on our 100 GHz quasi-optical gyrotron are reported. Although the project had to be abandoned due to technical problems, the conclusions are that for the 90 o scattering arrangement discussed it should be possible to determine at least one velocity component with an acceptable signal-to-noise ratio. (author) 11 figs., 10 refs

  19. Measurements of the parametric decay of CO2 laser radiation into plasma waves at quarter critical density using ruby laser Thomson scattering

    International Nuclear Information System (INIS)

    Schuss, J.J.; Chu, T.K.; Johnson, L.C.

    1977-11-01

    We report the results of small-angle ruby laser Thomson scattering measurements of the parametric excitation of plasma waves by CO 2 laser radiation at quarter-critical density in a laser-heated gas target plasma. From supplementary data obtained from interferometry and large-angle ruby laser scattering we infer that the threshold conditions for a convective decay are satisfied

  20. Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects

    Energy Technology Data Exchange (ETDEWEB)

    Tojo, H., E-mail: tojo.hiroshi@qst.go.jp; Hiratsuka, J.; Yatsuka, E.; Hatae, T.; Itami, K. [National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193 (Japan); Yamada, I.; Yasuhara, R.; Funaba, H.; Hayashi, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Ejiri, A.; Togashi, H.; Takase, Y. [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561 (Japan)

    2016-09-15

    This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (T{sub e}) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured T{sub e} and intensity of the signals. How accurate the values are depends on the electron temperature (T{sub e}) 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 T{sub e} 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 T{sub e} in a wide T{sub e} 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 T{sub e} measurements are valid under harsh radiation conditions. This method to obtain T{sub e} can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

  1. Electron temperature and density profiles measurement in the TJ-1 tokamak by Thomson scattering

    International Nuclear Information System (INIS)

    Pardo, C.; Zurro, B.

    1986-01-01

    Electron temperature and density profiles of ohmically heated hydrogen plasmas in the TJ-1 tokamak have been measured by Thomson scattering. The temperature profile peaks sharply in the central region while the density profile is very flat. Temperature values between 100 and 390 eV have been measured for densities in the range of 5.10 12 to 2.6.10 13 cm -3 . Parameters characterizing TJ-1 plasma, such as confinement times Z eff , have been deduced from experimental data. Energy confinement times are compared with experimental scaling laws. (author)

  2. Technical development and operation of TV thomson scattering system on JFT-2M tokamak

    International Nuclear Information System (INIS)

    Shiina, Tomio; Yamauchi, Toshihiko; Ishige, Yoichi

    1998-10-01

    Six years have passed since the TV Thomson scattering system (TVTS) was completed and the operation was started on the JFT-2M tokamak. TVTS was developed in collaboration with Princeton Plasma Physics Laboratory. Many troubles on the hardware are and the software are were encountered. Improvements of the system were needed in each occasion. Phenomena of troubles were carefully analyzed and they have been solved in operating the system. This paper presents thus obtained know-how necessary for the operation of TVTS as well as methods of operation. (author)

  3. Progress On The Thomson Scattering Diagnostic For The Helicon Plasma Experiment (HPX)

    Science.gov (United States)

    Green, A.; Emami, T.; Davies, R.; Frank, J.; Hopson, J.; Karama, J.; James, R. W.; Hopson, J.; Paolino, R. N.; Sandri, E.; Turk, J.; Wicke, M.; Cgapl Team

    2017-10-01

    A high-performance spectrometer utilizing volume-phase-holographic (VPH) grating and a charge coupled device (CCD) camera with a range of 380-1090 nm and resolution of 1024x1024 has been assembled on HPX at the Coast Guard Academy Plasma Laboratory (CGAPL). This spectrometer will collect doppler shifted photons, emitted from the plasma by the first harmonic (1064 nm) of a 2.5 J Nd:YAG laser. Direct measurements of the plasma's temperature and density will be determined using HPX's Thomson Scattering (TS) single spatial point diagnostic system. A zero order half wave plate rotates the polarization of the second harmonic TS laser beam when operating at a wavelength of 532 nm. A linear actuated periscope has been constructed to remotely redirect the beam so that 532 and 1064 nm wavelengths can both be used. TS has the capability of determining plasma properties on short time scales and will be used to create a robust picture of the internal plasma parameters. Operating at both 532 and 1064 nm results in a self-consistent measurement and better use our existing spectrometer and soon to be constructed polychrometer. A prototype spectrometer has been constructed to explore the Andor CCD camera's resolution and sensitivity. The current status of the diagnostic development, spectrometer, and collection optics system will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY17.

  4. Study of early laser-induced plasma dynamics: Transient electron density gradients via Thomson scattering and Stark Broadening, and the implications on laser-induced breakdown spectroscopy measurements

    International Nuclear Information System (INIS)

    Diwakar, P.K.; Hahn, D.W.

    2008-01-01

    To further develop laser-induced breakdown spectroscopy (LIBS) as an analytical technique, it is necessary to better understand the fundamental processes and mechanisms taking place during the plasma evolution. This paper addresses the very early plasma dynamics (first 100 ns) using direct plasma imaging, light scattering, and transmission measurements from a synchronized 532-nm probe laser pulse. During the first 50 ns following breakdown, significant Thomson scattering was observed while the probe laser interacted with the laser-induced plasma. The Thomson scattering was observed to peak 15-25 ns following plasma initiation and then decay rapidly, thereby revealing the highly transient nature of the free electron density and plasma equilibrium immediately following breakdown. Such an intense free electron density gradient is suggestive of a non-equilibrium, free electron wave generated by the initial breakdown and growth processes. Additional probe beam transmission measurements and electron density measurements via Stark broadening of the 500.1-nm nitrogen ion line corroborate the Thomson scattering observations. In concert, the data support the finding of a highly transient plasma that deviates from local thermodynamic equilibrium (LTE) conditions during the first tens of nanoseconds of plasma lifetime. The implications of this early plasma transient behavior are discussed in the context of plasma-analyte interactions and the role on LIBS measurements

  5. Particle-in-cell modeling of laser Thomson scattering in low-density plasmas at elevated laser intensities

    Science.gov (United States)

    Powis, Andrew T.; Shneider, Mikhail N.

    2018-05-01

    Incoherent Thomson scattering is a non-intrusive technique commonly used for measuring local plasma density. Within low-density, low-temperature plasmas and for sufficient laser intensity, the laser may perturb the local electron density via the ponderomotive force, causing the diagnostic to become intrusive and leading to erroneous results. A theoretical model for this effect is validated numerically via kinetic simulations of a quasi-neutral plasma using the particle-in-cell technique.

  6. Collective Thomson scattering in tokamaks having energetic ions

    International Nuclear Information System (INIS)

    Myer, R.C.; Woskov, P.P.; Machuzak, J.S.; Sigmar, D.J.; Cohn, D.R.; Bretz, N.L.; Efthimion, P.C.; Colestock, P.L.

    1989-01-01

    The authors discuss how collective Thomson scattering (CTS), using high power gyrotrons or long wavelength lasers,m shows promise as a powerful non-intrusive diagnostic of fast-ion transport as it may be capable of measuring the fast-ion velocity distribution and density profile with good spatial and temporal resolution. In addition, CTS may be used as a diagnostic for detecting localized power deposition in the background plasma. High power CTS systems are presently being planned for TFTR, JET, and CIT. Recent theoretical analysis suggests that an energetic (200-800 keV) He 3 minority can be produced in TFTR by ion cyclotron heating (ICH). Such an energetic population would be useful for simulating the energetic alpha-particles produced in a burning plasma. Since the ICH generated distribution is non-Maxwellian, the authors generalize the theoretical analysis of CTS to allow for particle distributions which can be represented by various orthogonal polynomial expansions. They evaluate the efficacy of CTS in detecting a fast He 3 component and determine the sensitivity of the diagnostic to the details of the ion distribution. In particular, the effectiveness of a planned 56 GHz gyrotron CTS diagnostic for TFTR is evaluated

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Stefanikova, E. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Division of Fusion Plasma Physics, KTH Royal Institute of Technology, SE-10691 Stockholm (Sweden); Peterka, M. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); MFF Charles University, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Bohm, P., E-mail: bohm@ipp.cas.cz; Bilkova, P.; Aftanas, M.; Urban, J.; Hron, M.; Panek, R. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Sos, M. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic)

    2016-11-15

    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.

  9. Control and acquisition for MAST Thomson scattering diagnostics

    International Nuclear Information System (INIS)

    Shibaev, S.; Naylor, G.; Scannell, R.; McArdle, G.; O'Gorman, T.; Walsh, M.J.

    2010-01-01

    The MAST (mega-amp spherical tokamak) Thomson scattering (TS) diagnostics have been radically upgraded and expanded. Eight 30 Hz 1.6 J Nd:YAG lasers have been combined to produce a sampling rate of 240 Hz. The scattered signals are acquired by two spectrometer systems: core and edge. The core system has been built anew: collection optics, polychromators, digitizers, and control computers. It allows measurement of electron temperature and density at 130 spatial points with ∼10 mm resolution across the plasma. The Nd:YAG scattered light signals are registered in 650 channels as polychromator outputs; each channel is registered on two ADCs: at 1 GHz rate in a short interval around each laser pulse and at 100 kHz for background data. The fast ADCs are combined in 26 data acquisition units. Each unit is assembled in a 6 U PXI chassis with embedded controller and six 4-channel 1 GHz ADC cards. Some chassis contain a 96-channel slow ADC card with Ethernet control. The Ruby TS has been rebuilt with a new spectrometer and CCD camera to provide higher spatial resolution - 512 points; the laser has been modified to add double pulse capability. A new control and acquisition system has been developed; it has modular design allowing flexibility and seamless expansion. The system supports event-triggered and real-time operation (will be added in a later stage). A smart trigger device has been developed for TS timing and synchronisation. It provides complex pulse sequences for laser firing with resynchronisation on a number of digital and analogue inputs including plasma events. This device also triggers TS acquisition. The system is integrated by a TS master process running on the dedicated computer; it is represented as a standard MAST data acquisition unit. The Ruby TS is also implemented as a standard MAST unit linked with the Nd:YAG TS by MAST system services.

  10. Upgrade of the automatic analysis system in the TJ-II Thomson Scattering diagnostic: New image recognition classifier and fault condition detection

    NARCIS (Netherlands)

    Makili, L.; Vega, J.; Dormido-Canto, S.; Pastor, I.; Pereira, A.; Farias, G.; Portas, A.; Perez-Risco, D.; Rodriguez-Fernandez, M. C.; Busch, P.

    2010-01-01

    An automatic image classification system based on support vector machines (SVM) has been in operation for years in the TJ-II Thomson Scattering diagnostic. It recognizes five different types of images: CCD camera background, measurement of stray light without plasma or in a collapsed discharge,

  11. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2014-01-01

    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 cyclot...

  12. H{sub {beta}} Stark broadening in cold plasmas with low electron densities calibrated with Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, J.M., E-mail: j.m.palomares-linares@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Huebner, S.; Carbone, E.A.D.; Vries, N. de; Veldhuizen, E.M. de [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Sola, A.; Gamero, A. [Departamento de Fisica, Universidad de Cordoba, Campus de Rabanales, ed. C-2, 14071 Cordoba (Spain); Mullen, J.J.A.M. van der [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2012-07-15

    In the present work Stark broadening measurements have been carried out on low electron density (n{sub e} < 5{center_dot}10{sup 19} m{sup -3}) and (relatively) low gas temperature (T{sub g} < 1100 K) argon-hydrogen plasma, under low-intermediate pressure conditions (3 mbar-40 mbar). A line fitting procedure is used to separate the effects of the different broadening mechanisms (e.g. Doppler and instrumental broadening) from the Stark broadening. A Stark broadening theory is extrapolated to lower electron density values, below its theoretical validity regime. Thomson scattering measurements are used to calibrate and validate the procedure. The results show an agreement within 20%, what validates the use of this Stark broadening method under such low density conditions. It is also found that Stark broadened profiles cannot be assumed to be purely Lorentzian. Such an assumption would lead to an underestimation of the electron density. This implies that independent information on the gas temperature is needed to find the correct values of n{sub e}. - Highlights: Black-Right-Pointing-Pointer Stark broadening measurements at low density and temperature conditions Black-Right-Pointing-Pointer Calibration with Thomson scattering Black-Right-Pointing-Pointer Indications of the non-Lorentzian shape of the Stark broadening Black-Right-Pointing-Pointer Impossibility of simultaneous diagnostic of gas temperature and electron density.

  13. Laser Thomson scattering diagnostics of non-equilibrium high pressure plasmas

    International Nuclear Information System (INIS)

    Muraoka, K.; Uchino, K.; Bowden, M.D.; Noguchi, Y.

    2001-01-01

    For various applications of non-equilibrium high pressure plasmas, knowledge of electron properties, such as electron density, electron temperature and/or electron energy distribution function (eedf), is prerequisite for any rational approach to understanding physical and chemical processes occurring in the plasmas. For this purpose, laser Thomson scattering has been successfully applied for the first time to measure the electron properties in plasmas for excimer laser pumping and in microdischarges. Although this diagnostic technique is well established for measurements in high temperature plasmas, its applications to these glow discharge plasmas have had various inherent difficulties, such as a presence of high density neutral particles (>10 21 m -3 ) in the excimer laser pumping discharges and an extremely small plasma size (<0.1 mm) and the presence of nearby walls for microdischarges. These difficulties have been overcome and clear signals have been obtained. The measured results are presented and their implications in the respective discharge phenomena are discussed

  14. Design proposal for a JFT-2M TV Thomson scattering system

    International Nuclear Information System (INIS)

    Dimock, D.; Yamauchi, Toshihiko.

    1988-07-01

    A design for the optics of a TV Thomson scattering system for JFT-2M is presented, which will measure electron temperature and density profiles having up to 82 points, spanning the horizontal mid plane of the machine. A detailed design for the collecting optics is presented since it is critical to the success of the system. It is shown that the Bouwers type catadioptric collection optics can be color corrected allowing the system to be used over a wide wavelength range. The laser requirements are presented and are easily met with commercially available systems. Two sketches of spectrometer designs are presented for two different sizes of detector. The detector gating and readout requirements are presented and can be met in existing detector systems. The importance of developing larger area detectors is emphasized and a possible detector system is presented. (author)

  15. Measurement of high-beta tokamak pressure profiles with multipoint Thomson scattering

    International Nuclear Information System (INIS)

    Levinton, F.M.

    1983-01-01

    A multipoint Thomson-scattering system has been developed to obtain pressure profiles along the major radius of Torus II, a high-beta tokamak. The profiles obtained during the 20 to 25 μs lifetime of the discharge indicates that the plasma has a peak temperature of 80 eV and density of 1.0 x 10 15 cm - 3 . The profiles remain fairly constant during this time until the equilibrium is lost, after which the temperature and density decays to 10 eV and 10 14 cm - 3 very quickly (approx. 1 μs). Experimental results show Torus II has a high-beta ( approx. 10%) equilibrium, with a strong shift of the peak of the pressure profile towards the outside. Numerical results from a 2-D free boundary MHD equilibrium code have obtained equilibria which closely approximate the experimentally measured profiles

  16. The LIDAR Thomson Scattering Diagnostic on JET

    DEFF Research Database (Denmark)

    Salzmann, H.; Bundgaard, J.; Gadd, A.

    1988-01-01

    By combining the time‐of‐flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density are measured in a magnetically confined fusion plasma. This technique was realized for the first time on the JET tokamak. A ruby laser (3‐J pulse ener...

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

    Science.gov (United States)

    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

  18. REACHING ULTRA HIGH PEAK CHARACTERISTICS IN RELATIVISTIC THOMSON BACKSCATTERING

    International Nuclear Information System (INIS)

    POGORELSKY, I.V.; BEN ZVI, I.; HIROSE, T.; KASHIWAGI, S.; YAKIMENKO, V.; KUSCHE, K.; SIDDONS, P.; ET AL

    2001-01-01

    The concept of x-ray laser synchrotron sources (LSS) based on Thomson scattering between laser photons and relativistic electrons leads to future femtosecond light-source facilities fit to multidisciplinary research in ultra-fast structural dynamics. Enticed by these prospects, the Brookhaven Accelerator Test Facility (ATF) embarked into development of the LSS based on a combination of a photocathode RF linac and a picosecond CO 2 laser. We observed the record 1.7 x 10 8 x-ray photons/pulse yield generated via relativistic Thomson scattering between the 14 GW CO 2 laser and 60 MeV electron beam

  19. LIDAR Thomson scattering diagnostic on JET (invited)

    International Nuclear Information System (INIS)

    Salzmann, H.; Bundgaard, J.; Gadd, A.

    1988-01-01

    By combining the time-of-flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density are measured in a magnetically confined fusion plasma. This technique was realized for the first time on the JET tokamak. A ruby laser (3-J pulse energy, 300-ps pulse duration, 0.5-Hz repetition rate) together with a 700-MHz bandwidth detection and registration system yields a spatial resolution of about 12 cm. A spectrometer with six channels in the wavelength range 400--800 nm gives a dynamic range of the temperature measurements of 0.3--20 keV. The stray light problem in the backscatter geometry is overcome by spectral discrimination and gating of the photomultipliers. A ruby filter in the spectral channel containing the laser wavelength allows calibration of the vignetting along the line of sight by means of Raman scattering, enabling the measurement of density profiles. The low level of background signal due to the short integration time for a single spatial point yields low statistical errors (ΔT/sub e/ /T/sub e/ ≅6%, Δn/sub e/ /n/sub e/ ≅4% at T/sub e/ = 6 keV, n/sub e/ = 3 x 10/sup 19/ m/sup -3/ ). Goodness-of-fit tests indicate that the systematic errors are within the same limits. The system is described and examples of measurements are given

  20. High-rep-rate Thomson scattering for LHD

    Science.gov (United States)

    den Hartog, D. J.; Borchardt, M. T.; Holly, D. J.; Schmitz, O.; Yasuhara, R.; Yamada, I.; Funaba, H.; Osakabe, M.; Morisaki, T.

    2017-10-01

    A high-rep-rate pulse-burst laser system is being built for the LHD Thomson scattering (TS) diagnostic. This laser will have two operating scenarios, a fast-burst sequence of 15 kHz rep rate for at least 15 ms, and a slow-burst sequence of 1 kHz for at least 50 ms. There will be substantial flexibility in burst sequences for tailoring to experimental requirements. This new laser system will operate alongside the existing lasers in the LHD TS diagnostic, and will use the same beamline. This increase in temporal resolution capability complements the high spatial resolution (144 points) of the LHD TS diagnostic, providing unique measurement capability unmatched on any other fusion experiment. The new pulse-burst laser is a straightforward application of technology developed at UW-Madison, consisting of a Nd:YAG laser head with modular flashlamp drive units and a customized control system. Variable pulse-width drive of the flashlamps is accomplished by IGBT (insulated gate bipolar transistor) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, producing >1.5 J q-switched pulses with 20 ns FWHM. Burst operation of this laser system will be used to capture fast time evolution of the electron temperature and density profiles during events such as ELMs, RMP perturbations, and various MHD modes. This work is supported by the U. S. Department of Energy and the National Institute for Fusion Science (Japan).

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. Y. [National Fusion Research Institute, Gunsan (Korea, Republic of)

    2014-10-15

    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.

  2. Mechanism design of the Thomson scattering diagnostic system for the TMX east mirror plug

    International Nuclear Information System (INIS)

    Lang, D.D.; Goodman, R.K.; Jenkins, S.L.; Wilkerson, J.A.; Parkinson, J.L.

    1979-01-01

    This Thomson scattering diagnostic system is used to measure the electron temperature and density of the east mirror plug of the Tandem Mirror Experiment (TMX) at Lawrence Livermore Laboratory. The measurements are made by firing a high-power ruby laser pulse through the plasma where the electrons then re-radiate a small fraction of the light. Because of the velocity of the electrons, the wavelength of the re-radiated light is Doppler shifted. The width of the Doppler-shifted wavelength spectrum is a measure of the temperature of the electrons in the plasma, and the total amount of re-radiated light is proportional to the electron density

  3. Impact of ICRH on the measurement of fusion alphas by collective Thomson scattering in ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Eriksson, L.-G.; Bindslev, Henrik

    2009-01-01

    Collective Thomson scattering (CTS) has been proposed for measuring the phase space distributions of confined fast ion populations in ITER plasmas. This study determines the impact of fast ions accelerated by ion cyclotron resonance heating (ICRH) on the ability of CTS to diagnose fusion alphas......, corresponding to an off-axis resonance. The sensitivities of the results to the He-3 concentration (0.1-4%) and the heating power (20-40 MW) are considered. Fusion born alphas dominate the total CTS signal for large Doppler shifts of the scattered radiation. The tritons generate a negligible fraction...... perpendicular velocities, it may be difficult to draw conclusions about the physics of alpha particles alone by CTS. With this exception, the CTS diagnostic can reveal the physics of the fusion alphas in ITER even under the presence of fast ions due to ICRH....

  4. Production of High Harmonic X-ray Radiation from Non-linear Thomson Scattering at LLNL PLEIADES

    International Nuclear Information System (INIS)

    Lim, J; Doyuran, A; Frigola, P; Travish, G; Rosenzweig, J; Anderson, S; Betts, S; Crane, J; Gibson, D; Hartemann, F; Tremaine, A

    2005-01-01

    We describe an experiment for production of high harmonic x-ray radiation from Thomson backscattering of an ultra-short high power density laser by a relativistic electron beam at the PLEIADES facility at LLNL. In this scenario, electrons execute a ''figure-8'' motion under the influence of the high-intensity laser field, where the constant characterizing the field strength is expected to exceed unity: a L = eE L /m e cw L (ge) 1. With large a L this motion produces high harmonic x-ray radiation and significant broadening of the spectral peaks. This paper is intended to give a layout of the PLEIADES experiment, along with progress towards experimental goals

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

    Science.gov (United States)

    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 (λ 0 -210 nm) will be used to optimize the scattered signal for plasma densities of 5 × 10 20 electrons/cm 3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 10 19 electrons/cm 3 . 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.

  6. Time resolved Thomson scattering diagnostic of pulsed gas metal arc welding (GMAW) process

    International Nuclear Information System (INIS)

    Kühn-Kauffeldt, M; Schein, J; Marquès, J L

    2014-01-01

    In this work a Thomson scattering diagnostic technique was applied to obtain time resolved electron temperature and density values during a gas metal arc welding (GMAW) process. The investigated GMAW process was run with aluminum wire (AlMg 4,5 Mn) with 1.2 mm diameter as a wire electrode, argon as a shielding gas and peak currents in the range of 400 A. Time resolved measurements could be achieved by triggering the laser pulse at shifted time positions with respect to the current pulse driving the process. Time evaluation of resulting electron temperatures and densities is used to investigate the state of the plasma in different phases of the current pulse and to determine the influence of the metal vapor and droplets on the plasma properties

  7. The LIDAR Thomson scattering diagnostic on JET

    International Nuclear Information System (INIS)

    Salzmann, H.; Gadd, A.

    1989-01-01

    By combining the time-of-flight or LIDAR principle with a Thomson backscatter diagnostic, spatial profiles of the electron temperature and density can be measured with a single set of detectors for all spatial points. This approach considerably simplifies the collection optics required for measuring a spatial profile. The system is described and examples of measurements are given and compared with the results of other diagnostics. (author)

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

    International Nuclear Information System (INIS)

    Goodman, R.K.

    1982-01-01

    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

  9. FIR-laser scattering for JT-60

    International Nuclear Information System (INIS)

    Itagaki, Tokiyoshi; Matoba, Tohru; Funahashi, Akimasa; Suzuki, Yasuo

    1977-09-01

    An ion Thomson scattering method with far infrared (FIR) laser has been studied for measuring the ion temperature in large tokamak JT-60 to be completed in 1981. Ion Thomson scattering has the advantage of measuring spatial variation of the ion temperature. The ion Thomson scattering in medium tokamak (PLT) and future large tokamak (JET) requires a FIR laser of several megawatts. Research and development of FIR high power pulse lasers with power up to 0.6 MW have proceeded in ion Thomson scattering for future high-temperature tokamaks. The FIR laser power will reach to the desired several megawatts in a few years, so JAERI plans to measure the ion temperature in JT-60 by ion Thomson scattering. A noise source of the ion Thomson scattering with 496 μm-CH 3 F laser is synchrotron radiation of which the power is similar to NEP of the Schottky-barrier diode. However, the synchrotron radiation power is one order smaller than that when a FIR laser is 385 μm-D 2 O laser. The FIR laser power corresponding to a signal to noise ratio of 1 is about 4 MW for CH 3 F laser, and 0.4 MW for D 2 O laser if NEP of the heterodyne mixer is one order less. A FIR laser scattering system for JT-60 should be realized with improvement of FIR laser power, NEP of heterodyne mixer and reduction of synchrotron radiation. (auth.)

  10. Design and testing of a magnetic shield for the Thomson scattering photomultiplier tubes in the stray fields of the ERASMUS tokamak

    International Nuclear Information System (INIS)

    Desoppere, E.; Van Oost, G.

    1983-01-01

    A multiple coaxial shield system has been designed for the photomultiplier tubes of the ERASMUS tokamak Thomson scattering diagnostic. A stray field of 75 x 10 -4 T was reduced to 0.01 x 10 -4 T for a field parallel to the tube axis, and to 0.03 x 10 -4 T for a perpendicular field

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, T., E-mail: kobayashi.tatsuya@LHD.nifs.ac.jp; Yoshinuma, M.; Ohdachi, S. [National Institute for Fusion Science, Toki 509-5292 (Japan); SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292 (Japan); Ida, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292 (Japan); Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Itoh, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Moon, C.; Yamada, I.; Funaba, H.; Yasuhara, R.; Tsuchiya, H.; Yoshimura, Y.; Igami, H.; Shimozuma, T.; Kubo, S.; Tsujimura, T. I. [National Institute for Fusion Science, Toki 509-5292 (Japan); Inagaki, S. [Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan)

    2016-04-15

    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.

  13. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Porte, L.

    2008-01-01

    reported [Bindslev , Phys. Rev. Lett. 97, 205005 2006]. Here we extend the discussion of these results which were obtained at the TEXTOR tokamak. The fast ions are generated by neutral-beam injection and ion-cyclotron resonance heating. The CTS system uses 100-150 kW of 110-GHz gyrotron probing radiation......Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently...... of the velocity distribution after turnoff of the ion heating. These results are in close agreement with numerical simulations....

  14. Chevron beam dump for ITER edge Thomson scattering system

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  15. Chevron beam dump for ITER edge Thomson scattering system

    Energy Technology Data Exchange (ETDEWEB)

    Yatsuka, E.; Hatae, T.; Bassan, M.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Vayakis, G. [ITER Organization, 13115 St Paul Lez Durance Cedex (France)

    2013-10-15

    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.

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

    Science.gov (United States)

    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.

  17. The prospect for fuel ion ratio measurements in ITER by collective Thomson scattering

    DEFF Research Database (Denmark)

    Stejner Pedersen, Morten; Korsholm, Søren Bang; Nielsen, Stefan Kragh

    2012-01-01

    We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structures...... in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we...... conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on plasma composition, and we find that a CTS fuel ion ratio diagnostic could...

  18. Short interval measurement of the Thomson scattering system at the pellet injection by using the event triggering system in LHD

    International Nuclear Information System (INIS)

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

    2013-01-01

    We have demonstrated Thomson scattering measurements of a short interval less than 1 ms by using the event triggering system with a multi-laser configuration. We have tried to measure this system at the pellet injection and obtained electron temperature and density profiles before and just after the pellet injection. Obtained profiles were dramatically changed after pellet injection with shot-by-shot measurements. This measurement technique will contribute understanding the physics of the pellet deposition. (author)

  19. Generation of Attosecond x-ray pulse using Coherent Relativistic Nonlinear Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki Tae; Park, Seong Hee; Cha, Yong Ho; Jeong, Young Uk; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2005-07-01

    Relativistic plasma, a new regime in physics, has been opened due to the development in ultra-intense laser technology during the past decade. Not only the fundamental aspect of relativistic plasma are attractive but also its potential application seems to be significant especially in the area of the generation of high energy particles such as electrons, ions, positrons, and {gamma}-rays. The generation of x-ray radiation with a pulse width of sub-femtoseconds presently draws much attention because such a radiation allows one to explore ultra-fast dynamics of electrons and nucleons. Several schemes have been proposed and/or demonstrated to generate an ultra-short x-ray pulse: the relativistic Doppler shift of a backscattered laser pulse by a relativistic electron beam, the harmonic frequency upshift of a laser pulse by relativistic nonlinear motion of electrons, high order harmonic generation in the interaction of intense laser pulse with noble gases and solids The train of a few 100 attosecond pulses has been observed in the case of laser-noble gas interaction. When a low-intensity laser pulse is irradiated on an electron, the electron undergoes a harmonic oscillatory motion and generates a dipole radiation with the same frequency as the incident laser pulse, which is called Thomson scattering. As the laser intensity increases, the oscillatory motion of the electron becomes relativistically nonlinear, which leads to the generation of harmonic radiations, referred to as Relativistic Nonlinear Thomson Scattered (RNTS) radiation. The motion of the electron begins to be relativistic as the following normalized vector potential approaches to unity: a{sub 0}=8.5 x 10{sup -10} {lambda}{iota}{sup 1/2} , (1) where {lambda} is the laser wavelength in {mu}m and I the laser intensity in W/cm{sup 2} The RNTS radiation has been investigated in analytical ways. Recently, indebted to the development of the ultra-intense laser pulse, experiments on RNTS radiation have been carried

  20. Thomson scattering diagnostics of steady state and pulsed welding processes without and with metal vapor

    International Nuclear Information System (INIS)

    Kühn-Kauffeldt, M; Schein, J; Marqués, J-L

    2015-01-01

    Thomson scattering is applied to measure temperature and density of electrons in the arc plasma of the direct current gas tungsten arc welding (GTAW) process and pulsed gas metal arc welding (GMAW) process. This diagnostic technique allows to determine these plasma parameters independent from the gas composition and heavy particles temperature. The experimental setup is adapted to perform measurements on stationary as well as transient processes. Spatial and temporal electron temperature and density profiles of a pure argon arc in the case of the GTAW process and argon arc with the presence of aluminum metal vapor in the case of the GMAW process were obtained. Additionally the data is used to estimate the concentration of the metal vapor in the GMAW plasma. (fast track communication)

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

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T.; Kritcher, A. L.; Bachmann, B.; Burns, S.; Hawreliak, J.; House, A.; Landen, O. L.; LePape, S.; Ma, T.; Pak, A.; Swift, D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, 64291 Darmstadt (Germany); Kraus, D. [University of California, Berkeley, California 94720 (United States); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94309 (United States)

    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.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    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.

  3. BRIEF COMMUNICATION: Fast-ion redistribution due to sawtooth crash in the TEXTOR tokamak measured by collective Thomson scattering

    Science.gov (United States)

    Nielsen, S. K.; Bindslev, H.; Salewski, M.; Bürger, A.; Delabie, E.; Furtula, V.; Kantor, M.; Korsholm, S. B.; Leipold, F.; Meo, F.; Michelsen, P. K.; Moseev, D.; Oosterbeek, J. W.; Stejner, M.; Westerhof, E.; Woskov, P.; TEXTOR Team

    2010-09-01

    Here we present collective Thomson scattering measurements of 1D fast-ion velocity distribution functions in neutral beam heated TEXTOR plasmas with sawtooth oscillations. Up to 50% of the fast ions in the centre are redistributed as a consequence of a sawtooth crash. We resolve various directions to the magnetic field. The fast-ion distribution is found to be anisotropic as expected. For a resolved angle of 39° to the magnetic field we find a drop in the fast-ion distribution of 20-40%. For a resolved angle of 83° to the magnetic field the drop is no larger than 20%.

  4. Measurement of high-dynamic range x-ray Thomson scattering spectra for the characterization of nano-plasmas at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, M. J., E-mail: macdonm@umich.edu [University of Michigan, Ann Arbor, Michigan 48109 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Gorkhover, T. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Technische Universität, 10623 Berlin (Germany); Bachmann, B.; Hau-Riege, S. P.; Pardini, T.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bucher, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Argonne National Lab, Lemont, Illinois 60439 (United States); Carron, S. [California Lutheran University, Thousand Oaks, California 91360 (United States); Coffee, R. N.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Krzywinski, J.; O’Grady, C. P.; Osipov, T.; Swiggers, M. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Ferguson, K. R. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford University, Stanford, California 94305 (United States); Kraus, D. [University of California, Berkeley, California 94720 (United States); and others

    2016-11-15

    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.

  5. Physics of the ion acoustic wave driven by the stimulated Brillouin scattering instability

    International Nuclear Information System (INIS)

    Clayton, C.E.

    1984-01-01

    The ion acoustic wave excited in the stimulated Brillouin scattering (SBS) instability is probed via collective ruby-laser Thomson scattering in order to understand the low saturation level observed in the instability. Many of the features observed in the Brillouin backscattered CO 2 laser light from the underdense gas-target plasma are also observed in the Thomson scattered ruby light - from which it is learned that the ion acoustic wave grows exponentially and then saturates as the CO 2 pump power is increased. The primary advantage of the ruby Thomson scattering diagnostic is in its capability of providing simultaneous space and time resolved measurements of the ion wave amplitude. From these first such detailed measurements, it was found that the ion wave grows exponentially in space at a rate that agrees with the linear convective SBS theory. However, at higher pump powers, the ion wave saturates at an inferred amplitude of anti-n/n 0 approx. = 5 to 10%. Further increases in the pump power appear to result in an increase in the length over which the ion wave is saturated. A nearly constant SBS reflectivity in this saturated regime, however, suggests that the saturated ion wave does not contribute as much to the scattered power as would be expected from Bragg scattering theory. This apparent contradiction can be resolved if ion trapping is responsible for the saturation of the ion wave

  6. Experimental determination of EEDF and He{sub 2}{sup *} Rydberg-state density by Thomson scattering in a ns-pulsed atmospheric micro-discharge

    Energy Technology Data Exchange (ETDEWEB)

    Schregel, Christian-Georg; Luggenhoelscher, Dirk; Czarnetzki, Uwe [Institute for Plasma and Atomic Physics, Ruhr-University Bochum (Germany)

    2016-07-01

    An open question of major importance for the investigation of atmospheric micro plasmas is the shape of the EEDF. This has been addressed by using incoherent Thomson scattering as a non-invasive diagnostic. The technique has been applied to measure the temporal evolution (Δt=20 ns) of the EVDF for a pure Helium plasma between two plane molybdenum electrodes, 0.95 mm apart. The plasma is pulsed with a repetition rate of 5 kHz at 0.7 bar. Measurements were done by a 532 nm Nd:YAG laser and a triple grating spectrometer with a gated ICCD for detection. The setup allows for detection of electron energies between 0.5 eV and 12 eV with up to three orders of magnitude in the dynamic range. Additionally, time resolved optical emission spectra where recorded and the Helium metastable was density probed by laser absorption. With the different diagnostic data combined, variation of laser energy used in Thomson scattering could additionally be utilized as a probe for the absolute Helium Excimer Rydberg-state density, allowing a unique determination of absolute density values in the early stages of the afterglow. Peak electron densities of 2 . 10{sup 20} m{sup -3} with a peak electron temperature of 2 eV have been observed.

  7. Joule-Thomson Coefficient for Strongly Interacting Unitary Fermi Gas

    International Nuclear Information System (INIS)

    Liao Kai; Chen Jisheng; Li Chao

    2010-01-01

    The Joule-Thomson effect reflects the interaction among constituent particles of macroscopic system. For classical ideal gas, the corresponding Joule-Thomson coefficient is vanishing while it is non-zero for ideal quantum gas due to the quantum degeneracy. In recent years, much attention is paid to the unitary Fermi gas with infinite two-body scattering length. According to universal analysis, the thermodynamical law of unitary Fermi gas is similar to that of non-interacting ideal gas, which can be explored by the virial theorem P = 2E/3V. Based on previous works, we further study the unitary Fermi gas properties. The effective chemical potential is introduced to characterize the nonlinear levels crossing effects in a strongly interacting medium. The changing behavior of the rescaled Joule-Thomson coefficient according to temperature manifests a quite different behavior from that for ideal Fermi gas. (general)

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

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, C. M., E-mail: cjacobson@wisc.edu; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A. [Department of Physics, University of Wisconsin–Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2016-11-15

    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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  10. Development of collective Thomson scattering system using the gyrotrons of sub-tera Hz region

    International Nuclear Information System (INIS)

    Tatematsu, Y.; Kubo, S.; Nishiura, M.

    2010-11-01

    Collective Thomson scattering (CTS) system is being developed for fusion plasma and CTS measurement on the large helical device (LHD) plasma is discussed. Sub-terahertz frequencies are suitable to the probe beam for CTS on LHD. According to the feasibility study, frequency around 0.4 THz is best for the CTS measurement on LHD high density plasma, and power of 100 kW is required. Thus, only gyrotrons in the sub-terahertz range can meet these parameters. At the first stage of development, second harmonic gyrotrons have been developed. A sealed-off type of gyrotrons has been manufactured to improve a demountable one. Measured output power has increased to about 60 kW. In parallel with the development of gyrotrons, an actual CTS system using a 77 GHz gyrotron originally installed for heating is being developed as a benchmark of LHD CTS. A heterodyne receiver system of a fundamental mixer with a fixed frequency local oscillator was installed on the upstream of the transmission line. The probe beam is 100% power modulated at 50 Hz to separate the scattering component from background ECE. Signals that can be attributed to the CTS were obtained and the analysis method of these data is developed. (author)

  11. Analysis and Performance of the Thomson Scattering Diagnostics on HT-7 Tokamak Based on I-EMCCD

    International Nuclear Information System (INIS)

    Shao Chunqiang; Zhao Junyu; Zang Qing; Han Xiaofeng; Xi Xiaoqi; Yang Jianhua; Chen Hui; Hu Ailan

    2014-01-01

    A visible light imaging Thomson scattering (VIS-TVTS) diagnostic system has been developed for the measurement of plasma electron temperature on the HT-7 tokamak. The system contains a Nd:YAG laser (λ = 532 nm, repetition rate 10 Hz, total pulse duration ≍ 10 ns, pulse energy > 1.0 J), a grating spectrometer, an image intensifier (I.I.) lens coupled with an electron multiplying CCD (EMCCD) and a data acquisition and analysis system. In this paper, the measurement capability of the system is analyzed. In addition to the performance of the system, the capability of measuring plasma electron temperature has been proved. The profile of electron temperature is presented with a spatial resolution of about 0.96 cm (seven points) near the center of the plasma

  12. Interaction of relativistic electrons with an intense laser pulse: High-order harmonic generation based on Thomson scattering

    International Nuclear Information System (INIS)

    Hack, Szabolcs; Varró, Sándor; Czirják, Attila

    2016-01-01

    We investigate nonlinear Thomson scattering as a source of high-order harmonic radiation with the potential to enable attosecond light pulse generation. We present a new analytic solution of the electron’s relativistic equations of motion in the case of a short laser pulse with a sine-squared envelope. Based on the single electron emission, we compute and analyze the radiated amplitude and phase spectrum for a realistic electron bunch, with special attention to the correct initial values. These results show that the radiation spectrum of an electron bunch in head-on collision with a sufficiently strong laser pulse of sine-squared envelope has a smooth frequency dependence to allow for the synthesis of attosecond light pulses.

  13. Interaction of relativistic electrons with an intense laser pulse: High-order harmonic generation based on Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hack, Szabolcs [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary); Varró, Sándor [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Wigner Research Center for Physics, SZFI, PO Box 49, H-1525 Budapest (Hungary); Czirják, Attila [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary)

    2016-02-15

    We investigate nonlinear Thomson scattering as a source of high-order harmonic radiation with the potential to enable attosecond light pulse generation. We present a new analytic solution of the electron’s relativistic equations of motion in the case of a short laser pulse with a sine-squared envelope. Based on the single electron emission, we compute and analyze the radiated amplitude and phase spectrum for a realistic electron bunch, with special attention to the correct initial values. These results show that the radiation spectrum of an electron bunch in head-on collision with a sufficiently strong laser pulse of sine-squared envelope has a smooth frequency dependence to allow for the synthesis of attosecond light pulses.

  14. OBSERVATIONS OF LINEAR POLARIZATION IN A SOLAR CORONAL LOOP PROMINENCE SYSTEM OBSERVED NEAR 6173 Å

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Hilaire, Pascal; Martínez Oliveros, Juan-Carlos; Hudson, Hugh S.; Krucker, Säm; Bain, Hazel [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Schou, Jesper [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Couvidat, Sébastien, E-mail: shilaire@ssl.berkeley.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2014-05-10

    White-light observations by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager of a loop-prominence system occurring in the aftermath of an X-class flare on 2013 May 13 near the eastern solar limb show a linearly polarized component, reaching up to ∼20% at an altitude of ∼33 Mm, about the maximum amount expected if the emission were due solely to Thomson scattering of photospheric light by the coronal material. The mass associated with the polarized component was 8.2 × 10{sup 14} g. At 15 Mm altitude, the brightest part of the loop was 3(±0.5)% linearly polarized, only about 20% of that expected from pure Thomson scattering, indicating the presence of an additional unpolarized component at wavelengths near Fe I (617.33 nm). We estimate the free electron density of the white-light loop system to possibly be as high as 1.8 × 10{sup 12} cm{sup –3}.

  15. Multi-mode optical fibers for simultaneous 13-position measurements Thomson scattering apparatus in the JFT-2M tokamak

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Nakazawa, Ichiro; Matoba, Tohru; Ogura, Yoshiaki.

    1987-11-01

    The characteristics of fiber bundles for Thomson scattering optics are studied, whose fibers are made of multi-mode optical fibers. The variety of output patterns were observed by weighting on the fiber as well as by bending it after passing a He-Ne laser through a fiber bundle. This variety influenced the matching loss considerably. Then, the effect of former is larger than the latter, which is caused by the micro bending. And also, the spread of pulse width by weighting is connected with the spread of output pattern. The spread of pulse width was about 3ns at the most in a 2.3 m length of fiber bundle. (author)

  16. Time resolved Thomson scattering measurements on a high pressure mercury lamp

    International Nuclear Information System (INIS)

    Vries, N de; Zhu, X; Kieft, E R; Mullen, J van der

    2005-01-01

    Time resolved Thomson scattering (TS) measurements have been performed on an ac driven high pressure mercury lamp. For this high intensity discharge (HID) lamp, TS is coherent and a coherent fitting routine, including rotational Raman calibration, was used to determine n e and T e from the measured spectrum. The maximum electron density and electron temperature obtained in the centre of the discharge varied in a time period of 5 ms between 1 x 10 21 m -3 e 21 m -3 and 6500 K e < 7100 K. In order to test the non-intrusive character of TS, we have derived a general expression for the heating of the electrons. By applying this to our mercury lamp and laser settings, we have confirmed the non-intrusiveness of our method. This is supported by the experimental findings. Furthermore, because the TS results were obtained directly, thus, without the local thermodynamic equilibrium (LTE) assumptions, they enabled us to follow the deviations from LTE as a function of time. Contrary to the generally made assumption that HID lamps are in LTE, we have found deviations from both the thermal and chemical equilibrium inside the high pressure mercury lamp at different phases of the applied current

  17. Magnetic photon scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.

    1987-05-01

    The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)

  18. Progress on FIR interferometry and Thomson Scattering measurements on HIT-SI3

    Science.gov (United States)

    Everson, Christopher; Jarboe, Thomas; Morgan, Kyle

    2017-10-01

    Spatially resolved measurements of the electron temperature (Te) and density (ne) will be fundamental in assessing the degree to which HIT-SI3 demonstrates closed magnetic flux and energy confinement. Further, electron temperature measurements have not yet been made on an inductively-driven spheromak. Far infrared (FIR) interferometer and Thomson Scattering (TS) systems have been installed on the HIT-SI3 spheromak. The TS system currently implemented on HIT-SI3 was originally designed for other magnetic confinement experiments, and progress continues toward modifying and optimizing for HIT-SI3 plasmas. Initial results suggest that the electron temperature is of order 10 eV. Plans to modify the TS system to provide more sensitivity and accuracy at low temperatures are presented. The line-integrated ne is measured on one chord by the FIR interferometer, with densities near 5x1019 m-3. Four cylindrical volumes have been added to the HIT-SI3 apparatus to enhance passive pumping. It is hoped that this will allow for more control of the density during the 2 ms discharges. Density measurements from before and after the installation of the passive pumping volumes are presented for comparison.

  19. Design study of a traveling-wave Thomson-scattering experiment for the realization of optical free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Steiniger, Klaus; Loeser, Markus; Pausch, Richard; Schramm, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf (Germany); Technische Universitaet Dresden (Germany); Albach, Daniel; Debus, Alexander; Roeser, Fabian; Siebold, Matthias; Bussmann, Michael [Helmholtz-Zentrum Dresden-Rossendorf (Germany)

    2016-07-01

    We present an experimental setup strategy for the realization of an optical free-electron laser (OFEL) in the Traveling-Wave Thomson-Scattering geometry (TWTS). In TWTS, the electric field of petawatt class, pulse-front tilted laser pulses is used to provide an optical undulator field. This is passed by a relativistic electron bunch so that electron direction of motion and laser propagation direction enclose an interaction angle. The combination of side scattering and pulse-front tilt provides continuous overlap of electrons and laser pulse over meter scale distances which are achieved with centimeter wide laser pulses. An experimental challenge lies in shaping of these wide laser pulses in terms of laser dispersion compensation along the electron trajectory and focusing. In the talk we show how diffraction gratings in combination with mirrors are used to introduce and control dispersion of the laser in order to provide a plane wave laser field along the electron trajectory. Furthermore we give tolerance limits on alignment errors to operate the OFEL. Example setups illustrate functioning and demonstrate feasibility of the scheme.

  20. Scattering of linearly polarized Bessel beams by dielectric spheres

    Science.gov (United States)

    Shoorian, Hamed

    2017-09-01

    The scattering of a Linearly Polarized Bessel Beam (LPBB) by an isotropic and homogenous dielectric sphere is investigated. Using analytical relation between the cylindrical and the spherical vector wave functions, all the closed- form analytical expressions, in terms of spherical wave-functions expansions, are derived for the scattered field. It is shown that in the case of conical angle of incident Bessel beam is equal to zero, the Linearly Polarized Bessel Beam becomes a plane wave and its scattering coefficients become the same as the expansion coefficients of plane wave in Mie theory. The transverse Cartesian and spherical components of the electric field, scattered by a sphere are shown in the z-plane for different cases, moreover the intensity of the incident Bessel beam and the effects of its conical angle on the scattered field and the field inside the sphere are investigated. To quantitatively study the scattering phenomenon and the variations of the fields inside and outside of the sphere, the scattering and absorption efficiencies are obtained for the scattering of the linearly-polarized Bessel beam, and are compared with those of the plane wave scattering.

  1. Study of a filter spectrometer in the framework of a new method for measuring the temperature of thermonuclear plasmas by relativistic Thomson scattering

    International Nuclear Information System (INIS)

    Lasalle, J.

    1975-06-01

    A new method which greatly simplifies the number of measurements necessary for obtaining the temperature in thermonuclear plasmas, using the relativistic effects of Thomson scattering is presented. A few orders of magnitude are computed for probing the feasibility of such temperature measurements. The data used correspond to magnitudes relating to T.F.R. The characteristics of a filter equipped spectrometer are then defined in view of a double function: separation of the lambda>lambda laser and lambda [fr

  2. Scattering theory of the linear Boltzmann operator

    International Nuclear Information System (INIS)

    Hejtmanek, J.

    1975-01-01

    In time dependent scattering theory we know three important examples: the wave equation around an obstacle, the Schroedinger and the Dirac equation with a scattering potential. In this paper another example from time dependent linear transport theory is added and considered in full detail. First the linear Boltzmann operator in certain Banach spaces is rigorously defined, and then the existence of the Moeller operators is proved by use of the theorem of Cook-Jauch-Kuroda, that is generalized to the case of a Banach space. (orig.) [de

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

    International Nuclear Information System (INIS)

    Murillo, Michael S.

    2010-01-01

    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.

  4. Thomson scattering on a low-pressure, inductively-coupled gas discharge lamp

    International Nuclear Information System (INIS)

    Sande, M.J. van de; Mullen, J.J.A.M. van der

    2002-01-01

    Excitation and light production processes in gas discharge lamps are the result of inelastic collisions between atoms and free electrons in the plasma. Therefore, knowledge of the electron density n e and temperature T e is essential for a proper understanding of such plasmas. In this paper, an experimental system for laser Thomson scattering on a low-pressure, inductively-coupled gas discharge lamp and measurements of n e and T e in this lamp are presented. The experimental system is suitable for low electron temperatures (down to below 0.2 eV) and employs a triple grating spectrograph for a high stray light rejection, or equivalently a low stray light redistribution (R eff approximately 7x10 -9 nm -1 at 0.5 nm from the laser wavelength). The electron density detection limit of the system is n e approximately 10 16 m -3 . The modifications to the lamp that were necessary for the measurements are described, and results are presented and compared to previous work and trends expected from the electron particle and energy balances. The electron density and temperature are about n e approximately 10 19 m -3 and T e approximately 1 eV in the most active part of the plasma; the exact values depend on the argon filling pressure, the mercury pressure and the position in the lamp. (author)

  5. Rothmund - Thomson Syndrome

    Directory of Open Access Journals (Sweden)

    Sharma N. L

    2003-01-01

    Full Text Available Rothmund-Thomson syndrome is a rare geno-photodermatosis of children. Poikilodermatous cutaneous changes, growth retardation, juvenile cataract and high incidence of malignancy are its classical features. A Thomson type of Rothmund-Thomson syndrome with characteristic poikiloderma congenitale, growth retardation, absence of juvenile cataract and parental non-consanguinity is described in an 8 year old Indian girl.

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

    Energy Technology Data Exchange (ETDEWEB)

    Döppner, T., E-mail: doeppner1@llnl.gov; Bachmann, B.; Emig, J.; Hardy, M.; Kalantar, D. H.; Kritcher, A. L.; Landen, O. L.; Ma, T.; Wood, R. D. [Lawrence Livermore National Laboratory, Livermore, California 94720 (United States); Kraus, D.; Saunders, A. M. [University of California, Berkeley, California 94720 (United States); Neumayer, P. [Gesellschaft für Schwerionenphysik, Darmstadt (Germany); Falcone, R. W. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fletcher, L. B. [SLAC National Accelerator Laboratory, Menlo Park, California 94720 (United States)

    2016-11-15

    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.

  7. Comparative studies of the laser Thomson scattering and Langmuir probe methods for measurements of negative ion density in a glow discharge plasma

    International Nuclear Information System (INIS)

    Noguchi, M; Hirao, T; Shindo, M; Sakurauchi, K; Yamagata, Y; Uchino, K; Kawai, Y; Muraoka, K

    2003-01-01

    The newly developed method of the negative ion density measurement in a plasma by laser Thomson scattering (LTS) was checked by comparing the obtained results against an independent technique, namely the Langmuir probe method. Both measurements were performed at the same position of the same inductively coupled plasma. The results agree quite well with each other and this has given confidence in the LTS method of negative ion density measurement. At the same time, both methods are complementary to each other, because the Langmuir probe measurement requires knowledge of the positive ion mass number

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

    International Nuclear Information System (INIS)

    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 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

  9. Design of single-longitudinal-mode laser oscillator for edge Thomson scattering system in ITER

    International Nuclear Information System (INIS)

    Hatae, Takaki; Kusama, Yoshinori; Kubomura, Hiroyuki; Matsuoka, Shin-ichi

    2006-06-01

    A high output energy (5J) and high repetition rate (100 Hz) laser system is required for the edge Thomson scattering system in ITER. A YAG laser (Nd:YAG laser) is a first candidate for the laser system satisfying the requirements. It is important to develop a high beam quality and single longitudinal mode (SLM) laser oscillator in order to realize this high power laser system. In this design work, following activities relating to the SLM laser oscillator have been carried out: design of the laser head and the resonator, estimation of the output power for the SLM laser oscillator, consideration of the feedback control scheme and consideration of interface for amplification system to achieve required performance (5J, 100 Hz). It is expected that the designed laser diode (LD) pumped SLM laser oscillator realizes: 100 Hz of repetition rate, 10 mJ of output energy, 10 ns of pulse width, single longitudinal mode, TEM 00 of transversal mode, divergence less than 4 times of the diffraction limit, energy stability within 5%. (author)

  10. ITER fast ion collective Thomson scattering, conceptual design of 60 GHz system

    International Nuclear Information System (INIS)

    Meo, F.; Bindslev, H.; Korsholm, S.B.

    2007-08-01

    The collective Thomson scattering diagnostic for ITER at the 60 GHz range is capable of measuring the fast ion distribution parallel and perpendicular to the magnetic field at different radial locations simultaneously. The design is robust technologically with no moveable components near the plasma. The fast ion CTS diagnostic consists of two separate systems. Each system has its own RF launcher and separate set of detectors. The first system measures the perpendicular component of the fast ion velocity distribution. It consists of radially directed RF launcher and receiver, both located in the equatorial port on the low field side (LFS). This system will be referred to by the acronym LFS-BS system referring to the location of the receiver and the fact that it measures backscattered radiation. The second part of the CTS diagnostic measures the parallel component of the fast ion distribution. It consists of an RF launcher located in the mid-plane port on the LFS and a receiver mounted on the inner vacuum vessel wall that views the plasma from between two blanket modules. This system will be referred to as HFS-FS referring to the location of the receivers and that they measure forward scattered radiation. The design of both LFS-BS and HFS-FS receivers is aimed at measuring at different spatial locations simultaneously with no moveable components near the plasma. This report is a preliminary study of the hardware design and engineering constraints for this frequency range. Section 2 conceptually describes the two systems and their main components. Section 3 clarifies the impact of design parameters such as beam widths and scattering angle on the CTS measurements. With this in hand, the ITER measurement requirements are translated into constraints on the CTS system designs. An important result in this section is that systems can be designed inside these constraints. Section 4 outlines the technical feasibility and describes in more detail the design and the engineering

  11. Measurement of electron density and electron temperature of a cascaded arc plasma using laser Thomson scattering compared to an optical emission spectroscopic approach

    Science.gov (United States)

    Yong, WANG; Cong, LI; Jielin, SHI; Xingwei, WU; Hongbin, DING

    2017-11-01

    As advanced linear plasma sources, cascaded arc plasma devices have been used to generate steady plasma with high electron density, high particle flux and low electron temperature. To measure electron density and electron temperature of the plasma device accurately, a laser Thomson scattering (LTS) system, which is generally recognized as the most precise plasma diagnostic method, has been established in our lab in Dalian University of Technology. The electron density has been measured successfully in the region of 4.5 × 1019 m-3 to 7.1 × 1020 m-3 and electron temperature in the region of 0.18 eV to 0.58 eV. For comparison, an optical emission spectroscopy (OES) system was established as well. The results showed that the electron excitation temperature (configuration temperature) measured by OES is significantly higher than the electron temperature (kinetic electron temperature) measured by LTS by up to 40% in the given discharge conditions. The results indicate that the cascaded arc plasma is recombining plasma and it is not in local thermodynamic equilibrium (LTE). This leads to significant error using OES when characterizing the electron temperature in a non-LTE plasma.

  12. Thomson scattering if FIR radiation

    International Nuclear Information System (INIS)

    Evans, D.E.

    1976-12-01

    The frequency spectrum of radiation scattered by collective density fluctuations of electrons in a hot plasma is influenced by ion and electron temperatures, impurity concentration and plasma effective charge, magnetic field, and the level of microturbulence. A pulsed laser suitable for measuring collective scattering in a tokamak will have infrared wavelength, power of the order of MWs and bandwidth of a few 10s of MHz. The extent to which these conditions can be met by optically pumped submillimetre lasers, including narrow band oscillators, amplifiers and superradiance - injection assemblies operated in CH 3 F and D 2 O, under development at the Culham Laboratory, is discussed. (author)

  13. Invariant imbedding equations for linear scattering problems

    International Nuclear Information System (INIS)

    Apresyan, L.

    1988-01-01

    A general form of the invariant imbedding equations is investigated for the linear problem of scattering by a bounded scattering volume. The conditions for the derivability of such equations are described. It is noted that the possibility of the explicit representation of these equations for a sphere and for a layer involves the separation of variables in the unperturbed wave equation

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

    Science.gov (United States)

    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. Use of webcams as tools for alignment and supervision of a Thomson scattering system in the near infrared

    Energy Technology Data Exchange (ETDEWEB)

    Andrebe, Y., E-mail: yanis.andrebe@epfl.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland); Behn, R.; Duval, B.P.; Etienne, P.; Pitzschke, A. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Station 13, 1015 Lausanne (Switzerland)

    2011-10-15

    The alignment stability is a major concern for Thomson scattering systems. Even small angular deviations of the laser beams crossing the plasma lead to a loss of the calibration resulting in unreliable measurements of the electron density profile. For the TCV (Tokamak a Configuration Variable) installation, the beam paths from the laser output to the vacuum chamber are {approx}25 m long and include several optical components. In order to monitor the alignment on a regular basis, a set of 9 cameras has been installed at several locations along the beam path. They view the actual laser beam pattern by recording the scattered light from an intercepting optical surface (mirror or window) together with the position of markers used for reference. Small 'webcams' are used for this purpose; they feature adequate intensity response at the laser wavelength of 1.06 {mu}m, are compact, cheap and several units may be connected to a server PC simultaneously. The real-time images from all the cameras are accessible from a Web browser. This installation has proven to be extremely useful in the early detection of alignment problems and to assist the alignment procedure .

  16. 76 FR 50272 - West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased...

    Science.gov (United States)

    2011-08-12

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-75,099] West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased Workers From Adecco, Albuquerque, New... former workers of West, A Thomson Reuters Business, Thomson Reuters Legal Division, including On-Site...

  17. A Platform for X-Ray Thomson Scattering Measurements of Radiation Hydrodynamics Experiments on the NIF

    Science.gov (United States)

    Lefevre, Heath; Ma, Kevin; Belancourt, Patrick; MacDonald, Michael; Doeppner, Tilo; Keiter, Paul; Kuranz, Carolyn

    2017-10-01

    A recent experiment on the National Ignition Facility (NIF) radiographed the evolution of the Rayleigh-Taylor (RT) instability under high and low drive cases. This experiment showed that under a high drive the growth rate of the RT instability is reduced relative to the low drive case. The high drive launches a radiative shock, increases the temperature of the post-shock region, and ablates the spikes, which reduces the RT growth rate. The plasma parameters must be measured to validate this claim. We present a target design for making X-Ray Thomson Scattering (XRTS) measurements on radiation hydrodynamics experiments on NIF to measure the electron temperature of the shocked region in the above cases. Specifically, we show that a previously fielded NIF radiation hydrodynamics platform can be modified to allow sufficient signal and temperature resolution for XRTS measurements. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0002956 and the National Science Foundation through the Basic Plasma Science and Engineering program.

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

    Science.gov (United States)

    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.

  19. Measuring main-ion temperatures in ASDEX upgrade using scattering of ECRH radiation

    DEFF Research Database (Denmark)

    Pedersen, Morten Stejner; Nielsen, Stefan Kragh; Jacobsen, Asger Schou

    2016-01-01

    We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak.......We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak....

  20. ASHI: An All Sky Heliospheric Imager for Viewing Thomson-Scattered Light

    Science.gov (United States)

    Buffington, A.; Jackson, B. V.; Yu, H. S.; Hick, P. P.; Bisi, M. M.

    2017-12-01

    We have developed, and are now making a detailed design for an All-Sky Heliospheric Imager (ASHI), to fly on future deep-space missions. ASHI's principal long-term objective is acquisition of a precision photometric map of the inner heliosphere as viewed from deep space. Photometers on the twin Helios spacecraft, the Solar Mass Ejection Imager (SMEI) upon the Coriolis satellite, and the Heliospheric Imagers (HIs) upon the Solar-TErrestrial RElations Observatory (STEREO) twin spacecraft, all indicate an optimum instrument design for visible-light Thomson-scattering observations. This design views a hemisphere of sky starting a few degrees from the Sun. Two imagers can cover almost all of the whole sky. A key photometric specification for ASHI is 0.1% differential photometry: this enables the three dimensional reconstruction of density starting from near the Sun and extending outward. SMEI analyses have demonstrated the success of this technique: when employed by ASHI, this will provide an order of magnitude better resolution in 3-D density over time. We augment this analysis to include velocity, and these imagers deployed in deep space can thus provide high-resolution comparisons both of direct in-situ density and velocity measurements to remote observations of solar wind structures. In practice we find that the 3-D velocity determinations provide the best tomographic timing depiction of heliospheric structures. We discuss the simple concept behind this, and present recent progress in the instrument design, and its expected performance specifications. A preliminary balloon flight of an ASHI prototype is planned to take place next Summer.

  1. New physics capabilities from the upgraded Thomson scattering diagnostic on MAST

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, K J; Barratt, N; Snape, J; Tallents, G J; Thornton, A [Department of Physics, University of York, Heslington, York (United Kingdom); Chapman, I; Conway, N; Dunstan, M R; Field, A R; Garzotti, L; Kirk, A; Lloyd, B; Meyer, H; Naylor, G; O' Gorman, T; Scannell, R; Shibaev, S; Temple, D; Pinches, S; Valovic, M, E-mail: keiran.gibson@york.ac.u [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon (United Kingdom)

    2010-12-15

    The newly upgraded MAST Thomson scattering (TS) system provides excellent spatial resolution ({approx}1 cm) at over 130 radial locations across a full plasma diameter, and utilizes eight individual Nd: :YAG laser systems which can be fired sequentially, providing electron temperature and density profiles approximately every 4 ms throughout a plasma discharge. By operating the system in burst mode, whereby the laser separation can be adjusted to within a few microseconds of each other, it is possible to obtain detailed profiles of transient and periodic phenomena such as sawteeth crashes, massive gas injection for disruption mitigation and the temperature perturbations associated with neoclassical tearing mode (NTM) islands. Following Fitzpatrick et al (1995 Phys. Plasmas 2 825), we consider a simplified model in which finite parallel diffusive heat transport can provide a threshold for NTM island growth and demonstrate that the TS derived electron temperature profiles around an island can be used to obtain both the island width and the critical island width below which temperature gradients are maintained across the island, potentially removing the bootstrap current drive for the NTM. Initial results from high beta, neutral beam injection heated discharges on MAST show that the measured island width inferred from the TS data is in good agreement with magnetic estimates of the island width (considering both a cylindrical approximation and using a full field line tracing estimate). The temporal behaviour of the island width obtained from the magnetic diagnostics indicates that for the scenarios considered to date, finite parallel diffusion is likely to play an important role in NTM threshold physics in MAST.

  2. A modified linear algebraic approach to electron scattering using cubic splines

    International Nuclear Information System (INIS)

    Kinney, R.A.

    1986-01-01

    A modified linear algebraic approach to the solution of the Schrodiner equation for low-energy electron scattering is presented. The method uses a piecewise cubic-spline approximation of the wavefunction. Results in the static-potential and the static-exchange approximations for e - +H s-wave scattering are compared with unmodified linear algebraic and variational linear algebraic methods. (author)

  3. Ion temperature measurements of H-, D- and He-plasmas in the TCA tokamak by collective Thomson scattering of D2O laser radiation

    International Nuclear Information System (INIS)

    Behn, R.; Dicken, D.; Hackmann, J.; Salito, S.A.; Siegrist, M.R.

    1989-01-01

    Development of collective Thomson scattering as a method to measure the ion temperature of a tokamak plasma has been successful and encouraging results have been obtained during experiments on TCA in H-, D- and He-plasmas. Using a laser source in the far-infrared spectral region allows scattering angles close to 90 o , which results in excellent spatial resolution. The system installed on the TCA tokamak comprises an optically pumped D 2 O laser emitting 0.5 J in a 1.4 μs pulse on its Raman transition at 385μm. A heterodyne receiver with a Schottky barrier diode mixer has been chosen to detect the scattered radiation and analyze its spectral distribution in 12 channels of 80 MHz. Recent improvements of the mixer and 1st IF-amplifier yielded a system NEP of 2.2·10 -19 W/Hz. As a consequence we have obtained results which allow for the first time to evaluate the ion temperature T i in a single laser shot. (author) 3 figs., 1 tab

  4. Ultrashort x-ray pulse generation by nonlinear Thomson scattering of a relativistic electron with an intense circularly polarized laser pulse

    Directory of Open Access Journals (Sweden)

    F. Liu

    2012-07-01

    Full Text Available The nonlinear Thomson scattering of a relativistic electron with an intense laser pulse is calculated numerically. The results show that an ultrashort x-ray pulse can be generated by an electron with an initial energy of 5 MeV propagating across a circularly polarized laser pulse with a duration of 8 femtosecond and an intensity of about 1.1×10^{21}  W/cm^{2}, when the detection direction is perpendicular to the propagation directions of both the electron and the laser beam. The optimal values of the carrier-envelop phase and the intensity of the laser pulse for the generation of a single ultrashort x-ray pulse are obtained and verified by our calculations of the radiation characteristics.

  5. 76 FR 45879 - West, a Thomson Reuters Business, Thomson Reuters Legal, Including On-Site Leased Workers From...

    Science.gov (United States)

    2011-08-01

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-73,198] West, a Thomson Reuters Business, Thomson Reuters Legal, Including On-Site Leased Workers From Adecco, Including a Teleworker...-W-73,198 is hereby issued as follows: All workers of West, A Thomson Reuters Business, Thomson...

  6. Observations on the variability of linear polarization in late-type dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Huovelin, J.; Linnaluoto, S.; Tuominen, I.; Virtanen, H.

    1989-04-01

    Broadband (UBV) linear polarimetric observations of a sample of late-type (F7-K5) dwarfs are reported. The observations include ten stars and extend over a maximum of 20 nights. Seven stars show significant temporal variability of polarization, which could be interpreted as rotational modulation due to slowly varying magnetic regions. Magnetic intensification in saturated Zeeman sensitive absorption lines is suggested as the dominant effect connecting linear polarization with magnetic activity in the most active single late-type dwarfs, while the wavelength dependence in the less active stars could also be due to a combination of Rayleigh and Thomson scattering.

  7. Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

    International Nuclear Information System (INIS)

    Anderson, S.G.; Barty, C.P.J.; Betts, S.M.; Brown, W.J.; Crane, J.K.; Cross, R.R.; Fittinghoff, D.N.; Gibson, D.J.; Hartemann, F.V.; Kuba, J.; LaSage, G.P.; Rosenzweig, J.B.; Slaughter, D.R.; Springer, P.T.; Tremaine, A.M.

    2003-01-01

    We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10 20 photons/s/0.1% bandwidth/mm 2 /mrad 2 . Initial results are reported and compared to theoretical calculations

  8. Comparison of collective Thomson scattering signals due to fast ions in ITER scenarios with fusion and auxiliary heating

    DEFF Research Database (Denmark)

    Salewski, Mirko; Asunta, O.; Eriksson, L.-G.

    2009-01-01

    Auxiliary heating such as neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) will accelerate ions in ITER up to energies in the MeV range, i.e. energies which are also typical for alpha particles. Fast ions of any of these populations will elevate the collective Thomson...... functions of fast ions generated by NBI and ICRH are calculated for a steady-state ITER burning plasma equilibrium with the ASCOT and PION codes, respectively. The parameters for the auxiliary heating systems correspond to the design currently foreseen for ITER. The geometry of the CTS system for ITER...... is chosen such that near perpendicular and near parallel velocity components are resolved. In the investigated ICRH scenario, waves at 50MHz resonate with tritium at the second harmonic off-axis on the low field side. Effects of a minority heating scheme with He-3 are also considered. CTS scattering...

  9. Rayleigh scattering and depolarization ratio in linear alkylbenzene

    International Nuclear Information System (INIS)

    Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-01-01

    It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein–Smoluchowski–Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm

  10. Spectrometer Development in Support of Thomson Scattering Investigations for the Helicon Plasma Experiment (HPX)

    Science.gov (United States)

    Sandri, Eva; Davies, Richard; Azzari, Phil; Frank, John; Frank, Jackson; James, Royce; Hopson, Jordon; Duke-Tinson, Omar; Paolino, Richard; Sherman, Justin; Wright, Erin; Turk, Jeremy

    2016-10-01

    Now that reproducible plasmas have been created on the Helicon Plasma Experiment (HPX) at the Coast Guard Academy Plasma Laboratory (CGAPL), a high-performance spectrometer utilizing volume-phase-holographic (VPH) grating and a charge coupled device (CCD) camera with a range of 380-1090 nm and resolution of 1024x1024 is being assembled. This spectrometer will collect doppler shifted photons created by exciting the plasma with the first harmonic of a 2.5 J Nd:YAG laser at a wavelength of 1064 nm. Direct measurements of the plasma's temperature and density will be determined using HPX's Thomson Scattering (TS) system as a single spatial point diagnostic. TS has the capability of determining plasma properties on short time scales and will be used to create a robust picture of the internal plasma parameters. A prototype spectrometer has been constructed to explore the Andor CCD camera's resolution and sensitivity. Concurrently, through intensive study of the high energy TS system, safety protocols and standard operation procedures (SOP) for the Coast Guard's largest and most powerful Laser have been developed. The current status of the TS SOP, diagnostic development, and the collection optic's spectrometer will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY15-16.

  11. Modeling and design of radiative hydrodynamic experiments with X-ray Thomson Scattering measurements on NIF

    Science.gov (United States)

    Ma, K. H.; Lefevre, H. J.; Belancourt, P. X.; MacDonald, M. J.; Doeppner, T.; Keiter, P. A.; Kuranz, C. C.; Johnsen, E.

    2017-10-01

    Recent experiments at the National Ignition Facility studied the effect of radiation on shock-driven hydrodynamic instability growth. X-ray radiography images from these experiments indicate that perturbation growth is lower in highly radiative shocks compared to shocks with negligible radiation flux. The reduction in instability growth is attributed to ablation from higher temperatures in the foam for highly radiative shocks. The proposed design implements the X-ray Thomson Scattering (XRTS) technique in the radiative shock tube platform to measure electron temperatures and densities in the shocked foam. We model these experiments with CRASH, an Eulerian radiation hydrodynamics code with block-adaptive mesh refinement, multi-group radiation transport and electron heat conduction. Simulations are presented with SiO2 and carbon foams for both the high temperature, radiative shock and the low-temperature, hydrodynamic shock cases. Calculations from CRASH give estimations for shock speed, electron temperature, effective ionization, and other quantities necessary for designing the XRTS diagnostic measurement. This work is funded by the LLNL under subcontract B614207, and was performed under the auspices of the U.S. DOE by LLNL under Contract No. DE-AC52-07NA27344.

  12. Scattering measurements in Tokamak type devices

    International Nuclear Information System (INIS)

    Matoba, Tohru

    1975-03-01

    Theories, experiments and proposals for light scattering in Tokamak type devices are reviewed. Thomson scattering, measuring method of the current density distribution by scattering and resonance fluorescence are summarily described. These methods may be useful for diagnosis of the fusion plasmas. The report may help planning of the measuring apparatus for the fusion plasmas in future. (auth.)

  13. 76 FR 27365 - West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased...

    Science.gov (United States)

    2011-05-11

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-75,099] West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased Workers From ADECCO, Albuquerque, NM... Adjustment Assistance (TAA) applicable to workers and former workers of West, A Thomson Reuters Business...

  14. FIR laser scattering and heterodyne receiver measurements on Alcator C

    International Nuclear Information System (INIS)

    Woskoboinikow, P.; Praddaude, H.C.; Mulligan, W.J.; Cohn, D.R.; Lax, B.

    1982-01-01

    The MIT program to develop high power collective Thomson scattering diagnostics is presented. The D 2 O laser Thomson scattering system is operational on Alcator C tokamak. The major components include a 0.5 MW, 150 ns D 2 O laser, a heterodyne receiver mixer, a 25 MW, 381 μ DCOOD laser local oscillator and X-band I.F. electronics including a 32 channel multiplexer filter centered at 9.4 GHz with 80 MHz wide channels. Initial scattering measurement showed high level of stray D 2 O laser power. The spectrum was obtained by operating the Thomson scattering diagnostics with no plasma in the tokamak. An X-band notch filter was placed after the Schottky diode mixer to reject a 240 MHz band centered at 9.4 GHz. The stray light level was reduced by 16 to 20 db. Other sources of background noise such as strong non-thermal scattering and ECE did not appear to be a problem. A gas filled cell was placed on the Alcator C scattering system to reduce the level of stray light. Work is underway to improve the transverse mode quality of the laser and receiver to improve matching to the beam and viewing dumps. (Kato, T.)

  15. Linear attenuation coefficients of tissues from 1 keV to 150 keV

    Science.gov (United States)

    Böke, Aysun

    2014-09-01

    The linear attenuation coefficients and three interaction processes have been computed for liver, kidney, muscle, fat and for a range of x-ray energies from 1 keV to 150 keV. Molecular photoelectric absorption cross sections were calculated from atomic cross section data. Total coherent (Rayleigh) and incoherent (Compton) scattering cross sections were obtained by numerical integration over combinations of F2m(x) with the Thomson formula and Sm(x) with the Klein-Nishina formula, respectively. For the coherent (Rayleigh) scattering cross section calculations, molecular form factors were obtained from recent experimental data in the literature for values of xelements involved in tissue composition is 5 for liver, 47 for kidney, 44 for muscle and 3 for fat. The results are compared with previously published experimental and theoretical linear attenuation coefficients. In general, good agreement is obtained. The molecular form factors and scattering functions and cross sections are incorporated into a Monte Carlo program. The energy distributions of x-ray photons scattered from tissues have been simulated and the results are presented.

  16. Faraday effect on stimulated Raman scattering in the linear region

    Science.gov (United States)

    Liu, Z. J.; Li, B.; Xiang, J.; Cao, L. H.; Zheng, C. Y.; Hao, L.

    2018-04-01

    The paper presents the effect of Faraday rotation on stimulated Raman scattering (SRS). When light propagates along the magnetic field upon plasma, Faraday rotation occurs. The rotation angle can be expressed as {{d}}θ /{{d}}{s}=2.93× {10}-4B\\tfrac{{n}e/{n}c}{\\sqrt{1-{n}e/{n}c}} {cm}}-1 approximately, where θ is the rotation angle and s is distance, n e is the electron density, n c is the critical density and B is magnetic field in unit of Gauss. Both the incident light and Raman light have Faraday effects. The angle between the polarization directions of incident light and Raman light changes with position. The driven force of electron plasma wave also reduces, and then SRS scattering level is reduced. Faraday rotation effect can increase the laser intensity threshold of Raman scattering, even if the magnetic field strength is small. The circularly polarized light incident case is also compared with that of the linearly polarized light incident. The Raman scattering level of linearly polarized light is much smaller than that of circularly polarized light in the magnetized plasma. The difference between linearly and circularly polarized lights is also discussed.

  17. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic.

    Science.gov (United States)

    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 10 19 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.

  18. Non-Linear Rheological Properties and Neutron Scattering Investigation on Dilute Ring-Linear Blends

    DEFF Research Database (Denmark)

    Pyckhout-Hintzen, W.; Bras, A.R.; Wischnewski, A.

    in a filament stretching rheometer, followed by quenching, strong anisotropic scattering patterns were obtained which were described by affinely deformed rings which function as giant, polymeric chemical crosslinks or sliplinks and more or less isotropic topological contributions from the entangling...... with interpenetrating linear chains. At the same time the non-linear rheological and mechanical data fit to a non-affine slip-tube model as for moderately crosslinked networks and to interchain pressure models or a modified non-linear Doi-Edwards description for the observed strain hardening during the extensional...

  19. Linear systems formulation of scattering theory for rough surfaces with arbitrary incident and scattering angles.

    Science.gov (United States)

    Krywonos, Andrey; Harvey, James E; Choi, Narak

    2011-06-01

    Scattering effects from microtopographic surface roughness are merely nonparaxial diffraction phenomena resulting from random phase variations in the reflected or transmitted wavefront. Rayleigh-Rice, Beckmann-Kirchhoff. or Harvey-Shack surface scatter theories are commonly used to predict surface scatter effects. Smooth-surface and/or paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. A recent linear systems formulation of nonparaxial scalar diffraction theory applied to surface scatter phenomena resulted first in an empirically modified Beckmann-Kirchhoff surface scatter model, then a generalized Harvey-Shack theory that produces accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident and scattered angles than the classical Beckmann-Kirchhoff and the original Harvey-Shack theories. These new developments simplify the analysis and understanding of nonintuitive scattering behavior from rough surfaces illuminated at arbitrary incident angles.

  20. Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiang; Zhang, Zhenyu [Wuhan University, Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan (China); Liu, Qian; Zheng, Yangheng [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Han, Junbo [Huazhong University of Science and Technology, Wuhan National High Magnetic Field Center, Wuhan (China); Zhang, Xuan; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

    2015-11-15

    We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments. (orig.)

  1. Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiang, E-mail: xiangzhou@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Liu, Qian, E-mail: liuqian@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Han, Junbo [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan (China); Zhang, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Zhang, Xuan; Ding, Yayun [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China); Zheng, Yangheng [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Zhou, Li; Cao, Jun; Wang, Yifang [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China)

    2015-11-21

    We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments.

  2. Plasma cleaning of ITER edge Thomson scattering mock-up mirror in the EAST tokamak

    Science.gov (United States)

    Yan, Rong; Moser, Lucas; Wang, Baoguo; Peng, Jiao; Vorpahl, Christian; Leipold, Frank; Reichle, Roger; Ding, Rui; Chen, Junling; Mu, Lei; Steiner, Roland; Meyer, Ernst; Zhao, Mingzhong; Wu, Jinhua; Marot, Laurent

    2018-02-01

    First mirrors are the key element of all optical and laser diagnostics in ITER. Facing the plasma directly, the surface of the first mirrors could be sputtered by energetic particles or deposited with contaminants eroded from the first wall (tungsten and beryllium), which would result in the degradation of the reflectivity. The impurity deposits emphasize the necessity of the first mirror in situ cleaning for ITER. The mock-up first mirror system for ITER edge Thomson scattering diagnostics has been cleaned in EAST for the first time in a tokamak using radio frequency capacitively coupled plasma. The cleaning properties, namely the removal of contaminants and homogeneity of cleaning were investigated with molybdenum mirror insets (25 mm diameter) located at five positions over the mock-up plate (center to edge) on which 10 nm of aluminum oxide, used as beryllium proxy, were deposited. The cleaning efficiency was evaluated using energy dispersive x-ray spectroscopy, reflectivity measurements and x-ray photoelectron spectroscopy. Using argon or neon plasma without magnetic field in the laboratory and with a 1.7 T magnetic field in the EAST tokamak, the aluminum oxide films were homogeneously removed. The full recovery of the mirrors’ reflectivity was attained after cleaning in EAST with the magnetic field, and the cleaning efficiency was about 40 times higher than that without the magnetic field. All these results are promising for the plasma cleaning baseline scenario of ITER.

  3. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    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{sup −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 10{sup 19} cm{sup −2} Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

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

    Science.gov (United States)

    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

  5. Special Important Aspects of the Thomson Effect

    Science.gov (United States)

    Lashkevych, Igor; Velázquez, J. E.; Titov, Oleg Yu.; Gurevich, Yuri G.

    2018-03-01

    A comprehensive study of the mechanisms of heating and cooling originating from an electrical current in semiconductor devices is reported. The variation in temperature associated with the Peltier effect is not related to the presence of heat sources and sinks if the heat flux is correctly determined. The Thomson effect is commonly regarded as a heat source/sink proportional to the Thomson coefficient, which is added to the Joule heating. In the present work, we will show that this formulation of the Thomson effect is not sufficiently clear. When the heat flux is correctly defined, the Thomson heat source/sink is proportional to the Seebeck coefficient. In the conditions in which the Peltier effect takes place, the temperature gradient is created, and, consequently, the Thomson effect will occur naturally.

  6. A compact multichannel spectrometer for Thomson scatteringa)

    Science.gov (United States)

    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 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.

  7. Heldi Thomson

    Index Scriptorium Estoniae

    1997-01-01

    Teaduspreemia autorite kollektiivile arstiteaduse alal töö "Vähktõbi Eestis 1968-1992: haigestumus, levimus, elulemus ja suremus" eest - Mati Rahu (kollektiivi juht), Tiiu Aarelaid, Kaja Gornoi, Heldi Thomson

  8. Electron re-scattering from aligned linear molecules using the R-matrix method

    International Nuclear Information System (INIS)

    Harvey, A G; Tennyson, J

    2009-01-01

    Electron re-scattering in a strong laser field provides an important probe of molecular structure and processes. The laser field drives the ionization of the molecule, followed by acceleration and subsequent recollision of the electron with the parent molecular ion, the scattered electrons carry information about the nuclear geometry and electronic states of the molecular ion. It is advantageous in strong field experiments to work with aligned molecules, which introduces extra physics compared to the standard gas-phase, electron-molecule scattering problem. The formalism for scattering from oriented linear molecules is presented and applied to H 2 and CO 2 . Differential cross sections are presented for (re-)scattering by these systems concentrating on the most common, linear alignment. In H 2 these cross sections show significant angular structure which, particularly for a scattering angle of 90 deg., are predicted to vary significantly between re-collisions stimulated by an even or an odd number of photons. In CO 2 these cross sections are zero indicating the necessity of using non-parallel alignment with this molecule.

  9. Some aspects of transition radiation and scattering theory

    International Nuclear Information System (INIS)

    Ginzburg, V.L.; Tsytovich, V.N.

    1978-01-01

    Some aspects of transition radiation and transition scattering theory are considered. The transition radiation in vacuum is analysed in the presence of a strong magnetic field. It is shown, that the constant electro-magnetic field makes vacuum similar to the uniaxial ferrodielectric. The appearance of the transition radiation in the nonstationary medium is discussed when its properties in the medium change abruptly in time. It is obtained, that both types of the transition radiation for nonrelativistic particles (on an abrupt boundary of the two media interface and under an abrupt change in time of the medium properties) differ quantitatively (on the order of the value). The role of the radiation transition and scattering in plasma physics has been elucidated from different points. Four most important features of these processes are pointed out. Particularly, essential is shown to be the type of the transition scattering when one plasma wave, being the dielectric constant wave transforms into another one also a plasma wave. In the processes of the transition scattering an essential part is played by the effects of the space dispersion, particularly when the scattering takes place on the small velocity particles. Finally besides transition scattering there exists in plasma or in some cases prevails a Thomson scattering. In this case an important role in plasma is played by the interference between the Thomson and the transition scattering

  10. Hosing, sausaging, filamentation and side-scatter of a high-intensity short-pulse laser in an under-dense plasma

    International Nuclear Information System (INIS)

    Najmudin, Z.; Krushelnick, K.; Clark, E.L.; Salvati, M.; Santala, M.I.K.; Tatarakis, M.; Dangor, A.E.

    2000-01-01

    Previous studies of high-intensity short-pulse laser beams propagating in under-dense plasma have relied on spectrally integrated Thomson scattering images. Though interesting, many significant features of the interaction cannot be diagnosed by this method. We report on shadow-graphy and spectrally resolved Thomson scattering of such an interaction. These images reveal many processes previously predicted but unseen, such as the Raman side-scatter and filamentation instabilities. Also the interaction is shown to clearly demonstrate many propagation instabilities such as 'sausaging' and 'hosing' for the first time. (authors)

  11. Upgrade of the automatic analysis system in the TJ-II Thomson Scattering diagnostic: New image recognition classifier and fault condition detection

    International Nuclear Information System (INIS)

    Makili, L.; Vega, J.; Dormido-Canto, S.; Pastor, I.; Pereira, A.; Farias, G.; Portas, A.; Perez-Risco, D.; Rodriguez-Fernandez, M.C.; Busch, P.

    2010-01-01

    An automatic image classification system based on support vector machines (SVM) has been in operation for years in the TJ-II Thomson Scattering diagnostic. It recognizes five different types of images: CCD camera background, measurement of stray light without plasma or in a collapsed discharge, image during ECH phase, image during NBI phase and image after reaching the cut off density during ECH heating. Each kind of image implies the execution of different application software. Due to the fact that the recognition system is based on a learning system and major modifications have been carried out in both the diagnostic (optics) and TJ-II plasmas (injected power), the classifier model is no longer valid. A new SVM model has been developed with the current conditions. Also, specific error conditions in the data acquisition process can automatically be detected and managed now. The recovering process has been automated, thereby avoiding the loss of data in ensuing discharges.

  12. Upgrade of the automatic analysis system in the TJ-II Thomson Scattering diagnostic: New image recognition classifier and fault condition detection

    Energy Technology Data Exchange (ETDEWEB)

    Makili, L. [Dpto. Informatica y Automatica - UNED, Madrid (Spain); Vega, J. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain); Dormido-Canto, S., E-mail: sebas@dia.uned.e [Dpto. Informatica y Automatica - UNED, Madrid (Spain); Pastor, I.; Pereira, A. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain); Farias, G. [Dpto. Informatica y Automatica - UNED, Madrid (Spain); Portas, A.; Perez-Risco, D.; Rodriguez-Fernandez, M.C. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain); Busch, P. [FOM Institut voor PlasmaFysica Rijnhuizen, Nieuwegein (Netherlands)

    2010-07-15

    An automatic image classification system based on support vector machines (SVM) has been in operation for years in the TJ-II Thomson Scattering diagnostic. It recognizes five different types of images: CCD camera background, measurement of stray light without plasma or in a collapsed discharge, image during ECH phase, image during NBI phase and image after reaching the cut off density during ECH heating. Each kind of image implies the execution of different application software. Due to the fact that the recognition system is based on a learning system and major modifications have been carried out in both the diagnostic (optics) and TJ-II plasmas (injected power), the classifier model is no longer valid. A new SVM model has been developed with the current conditions. Also, specific error conditions in the data acquisition process can automatically be detected and managed now. The recovering process has been automated, thereby avoiding the loss of data in ensuing discharges.

  13. Real-time digital control, data acquisition, and analysis system for the DIII-D multipulse Thomson scattering diagnostic

    International Nuclear Information System (INIS)

    Greenfield, C.M.; Campbell, G.L.; Carlstrom, T.N.; DeBoo, J.C.; Hsieh, C.; Snider, R.T.; Trost, P.K.

    1990-01-01

    A VME-based real-time computer system for laser control, data acquisition, and analysis for the DIII-D multipulse Thomson scattering diagnostic is described. The laser control task requires precise timing of up to eight Nd:YAG lasers, each with an average firing rate of 20 Hz. A cpu module in a real-time multiprocessing computer system will operate the lasers with evenly staggered laser pulses or in a ''burst mode,'' where all available (fully charged) lasers can be fired at 50--100 μs intervals upon receipt of an external event trigger signal. One or more cpu modules, along with a LeCroy FERA (fast encoding and readout ADC) system, will perform real-time data acquisition and analysis. Partial electron temperature and density profiles will be available for plasma feedback control within 1 ms following each laser pulse. The VME-based computer system consists of two or more target processor modules (25 MHz Motorola 68030) running the VMEexec real-time operating system connected to a Unix-based host system (also a 68030). All real-time software is fully interrupt driven to maximize system efficiency. Operator interaction and (non-real-time) data analysis takes place on a MicroVAX 3400 connected via DECnet

  14. Linearized least-square imaging of internally scattered data

    KAUST Repository

    Aldawood, Ali; Hoteit, Ibrahim; Turkiyyah, George M.; Zuberi, M. A H; Alkhalifah, Tariq Ali

    2014-01-01

    Internal multiples deteriorate the quality of the migrated image obtained conventionally by imaging single scattering energy. However, imaging internal multiples properly has the potential to enhance the migrated image because they illuminate zones in the subsurface that are poorly illuminated by single-scattering energy such as nearly vertical faults. Standard migration of these multiples provide subsurface reflectivity distributions with low spatial resolution and migration artifacts due to the limited recording aperture, coarse sources and receivers sampling, and the band-limited nature of the source wavelet. Hence, we apply a linearized least-square inversion scheme to mitigate the effect of the migration artifacts, enhance the spatial resolution, and provide more accurate amplitude information when imaging internal multiples. Application to synthetic data demonstrated the effectiveness of the proposed inversion in imaging a reflector that is poorly illuminated by single-scattering energy. The least-square inversion of doublescattered data helped delineate that reflector with minimal acquisition fingerprint.

  15. Dielectric effects on Thomson scattering in a relativistic magnetized plasma

    DEFF Research Database (Denmark)

    Bindslev, H.

    1991-01-01

    The effects of the dielectric properties of a relativistic magnetized plasma on the scattering of electromagnetic radiation by fluctuations in electron density are investigated. The origin of the density fluctuations is not considered. Expressions for the scattering cross-section and the scattered...... power accepted by the receiving antenna are derived for a plasma with spatial dispersion. The resulting expressions allow thermal motion to be included in the description of the plasma and remain valid for frequencies of the probing radiation in the region of omega(p) and omega(ce), provided...... the absorption is small. Symmetry between variables relating to incident and scattered fields is demonstrated and shown to be in agreement with the reciprocity relation. Earlier results are confirmed in the cold plasma limit. Significant relativistic effects, of practical importance to the scattering...

  16. A real-time digital control, data acquisition and analysis system for the DIII-D multipulse Thomson scattering diagnostic

    International Nuclear Information System (INIS)

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

    1990-10-01

    A VME-based real-time computer systems for laser control, data acquisition and analysis for the DIII-D multipulse Thomson scattering diagnostic is described. The laser control task requires precise timing of up to 8 Nd:YAG lasers, each with an average firing rate of 20 Hz. A cpu module in real-time multiprocessing computer system will operate the lasers with evenly staggered laser pulses or in a ''burst mode'', where all available (fully charged) lasers can be fired at 50--100 μsec intervals upon receipt of an external event trigger signal. One of more cpu modules, along with a LeCroy FERA (Fast Encoding and Readout ADC) system, will perform real-time data acquisition and analysis. Partial electron temperature and density profiles will be available for plasma feedback control within 1 msec following each laser pulse. The VME-based computer system consists of 2 or more target processor modules (25 MHz Motorola 68030) running the VMEexec real-time operating system connected to a Unix based host system (also a 68030). All real-time software is fully interrupt driven to maximize system efficiency. Operator interaction and (non real-time) data analysis takes place on a MicroVAX 3400 connected via DECnet. 17 refs., 1 fig

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

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, J.M., E-mail: jmkr@danfysik.dk [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany); Budde, M.; Bødker, F. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Irman, A.; Jochmann, A. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Kristensen, J.P. [Danfysik A/S, Gregersensvej 8, 2630 Taastrup (Denmark); Lehnert, U.; Michel, P. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Schramm, U. [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstrasse 400, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany)

    2016-09-11

    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.

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

    CERN Document Server

    Krämer, J.M.; Bødker, F.; Irman, A.; .Jochmann A.; Kristensen, J.P.; Lehnert U., HZDR; Michel, P.; Schrammb, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    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 diverg...

  19. Electron Beam Final Focus System For Thomson Scattering At Elbe

    CERN Document Server

    Krämer, J.M.; Bødkera, F.; Irman, A.; Jochmann, A.; Kristensena, J.P.; Lehnert, U.; Michel, P.; Schramm, U.; 10.1016/j.nima.2015.10.067

    2016-01-01

    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 diverg...

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

    NARCIS (Netherlands)

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

    2012-01-01

    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

  1. The possibilities of linearized inversion of internally scattered seismic data

    KAUST Repository

    Aldawood, Ali

    2014-08-05

    Least-square migration is an iterative linearized inversion scheme that tends to suppress the migration artifacts and enhance the spatial resolution of the migrated image. However, standard least-square migration, based on imaging single scattering energy, may not be able to enhance events that are mainly illuminated by internal multiples such as vertical and nearly vertical faults. To alleviate this problem, we propose a linearized inversion framework to migrate internally multiply scattered energy. We applied this least-square migration of internal multiples to image a vertical fault. Tests on synthetic data demonstrate the ability of the proposed method to resolve a vertical fault plane that is poorly resolved by least-square imaging using primaries only. We, also, demonstrate the robustness of the proposed scheme in the presence of white Gaussian random observational noise and in the case of imaging the fault plane using inaccurate migration velocities.

  2. The possibilities of linearized inversion of internally scattered seismic data

    KAUST Repository

    Aldawood, Ali; Alkhalifah, Tariq Ali; Hoteit, Ibrahim; Zuberi, Mohammad; Turkiyyah, George

    2014-01-01

    Least-square migration is an iterative linearized inversion scheme that tends to suppress the migration artifacts and enhance the spatial resolution of the migrated image. However, standard least-square migration, based on imaging single scattering energy, may not be able to enhance events that are mainly illuminated by internal multiples such as vertical and nearly vertical faults. To alleviate this problem, we propose a linearized inversion framework to migrate internally multiply scattered energy. We applied this least-square migration of internal multiples to image a vertical fault. Tests on synthetic data demonstrate the ability of the proposed method to resolve a vertical fault plane that is poorly resolved by least-square imaging using primaries only. We, also, demonstrate the robustness of the proposed scheme in the presence of white Gaussian random observational noise and in the case of imaging the fault plane using inaccurate migration velocities.

  3. Electron-electron scattering in linear transport in two-dimensional systems

    DEFF Research Database (Denmark)

    Hu, Ben Yu-Kuang; Flensberg, Karsten

    1996-01-01

    We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

  4. Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1977--May 31, 1978

    International Nuclear Information System (INIS)

    York, T.M.; Klevans, E.H.

    1978-02-01

    Experimental and analytical studies of end loss from a theta pinch have been carried out. Detailed diagnostic studies of a 25 cm long theta pinch operating with reversed trapped fields have been completed; spectroscopic studies, magnetic probe, pressure probe, double diamagnetic loop, luminosity studies and Thomson scattering studies of the plasma have been carried out over the 8 μsec duration of the transient loss. Two new diagnostic techniques have been developed based on the available Thomson scattering laser source. A study of plasma loss from a 10.5 long theta pinch with an axial Twyman-Green interferometer has been completed and reported. The basic studies needed for subsequent experimental work on heat conduction loss being diagnosed by Thomson scattering data in the end region, with and without mirror coil, has been completed as a part of the mirror field studies

  5. Elastic scattering of low energy γ-rays

    International Nuclear Information System (INIS)

    Whittingham, I.B.

    1978-05-01

    Theoretical cross sections for the elastic scattering of 245, 334, 444, 779, 1086, 1112 and 1408 keV γ-rays by Pb are obtained for scattering angles up to 150 degrees. Three sets of Rayleigh scattering amplitudes have been computed using (1) the calculations of Johnson and Cheng, (2) the K shell calculations of Brown and co-workers supplemented by form factors amplitudes for higher shells, and (3) form factor amplitudes for all shells. Nuclear Thomson amplitudes have been included for all energies and, for 1408 keV, Delbruck scattering based upon the calculations of Papatzacos and Mork has been included. Nuclear resonance scattering is show to be negligble for all energies

  6. Estimation of biological parameters of marine organisms using linear and nonlinear acoustic scattering model-based inversion methods.

    Science.gov (United States)

    Chu, Dezhang; Lawson, Gareth L; Wiebe, Peter H

    2016-05-01

    The linear inversion commonly used in fisheries and zooplankton acoustics assumes a constant inversion kernel and ignores the uncertainties associated with the shape and behavior of the scattering targets, as well as other relevant animal parameters. Here, errors of the linear inversion due to uncertainty associated with the inversion kernel are quantified. A scattering model-based nonlinear inversion method is presented that takes into account the nonlinearity of the inverse problem and is able to estimate simultaneously animal abundance and the parameters associated with the scattering model inherent to the kernel. It uses sophisticated scattering models to estimate first, the abundance, and second, the relevant shape and behavioral parameters of the target organisms. Numerical simulations demonstrate that the abundance, size, and behavior (tilt angle) parameters of marine animals (fish or zooplankton) can be accurately inferred from the inversion by using multi-frequency acoustic data. The influence of the singularity and uncertainty in the inversion kernel on the inversion results can be mitigated by examining the singular values for linear inverse problems and employing a non-linear inversion involving a scattering model-based kernel.

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

    Science.gov (United States)

    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.

  8. Clasificador de Imágenes del Diagnóstico Thomson Scattering del TJ II Basado en Template Matching

    Directory of Open Access Journals (Sweden)

    Jesús A. Vega Sánchez

    2010-07-01

    Full Text Available La automatización del análisis de las señales generadas en un ambiente de fusión nuclear constituye una meta importante. El presente trabajo se encuadra en el contexto del desarrollo de clasificadores automáticos para las señales generadas en el Diagnóstico Thomson Scattering del TJ II, siendo este un ambiente de fusión específico. Dos etapas fundamentales son consideradas en el diseño del clasificador: el procesamiento de las señales y extracción de sus características, por un lado, y la clasificación, por otro. La primera es implementada, en el trabajo, recurriendo a las transformadas wavelet mientras que la segunda es implementada a través de la comparación entre las características de las señales disponibles y las de un conjunto de señales previamente seleccionadas como prototipos (template matching, operación esta que es efectuada utilizando a técnicas de trayectoria de búsqueda óptimas basadas en programación dinámica. En el mismo se muestra que la metodología empleada permite la clasificación de las señales en cuestión y que con un entrenamiento adecuado se puede extraer un buen rendimiento al clasificador desarrollado.

  9. Thomson scattering on argon surfatron plasmas at intermediate pressures: Axial profiles of the electron temperature and electron density

    International Nuclear Information System (INIS)

    Palomares, J.M.; Iordanova, E.; Veldhuizen, E.M. van; Baede, L.; Gamero, A.; Sola, A.; Mullen, J.J.A.M. van der

    2010-01-01

    The axial profiles of the electron density n e and electron temperature T e of argon surfatron plasmas in the pressure range of 6-20 mbar and microwave power between 32 and 82 W have been determined using Thomson Scattering of laser irradiation at 532 nm. For the electron density and temperature we found values in the ranges 5 x 10 18 e 19 m -3 and 1.1 e e and T e down to 8% and 3%, respectively. It is found that n e decreases in the direction of the wave propagation with a slope that is nearly constant. The slope depends on the pressure but not on the power. Just as predicted by theories we see that increasing the power leads to longer plasma columns. However, the plasmas are shorter than what is predicted by theories based on the assumption that for the plasma-wave interaction electron-atom collisions are of minor importance (the so-called collisionless regime). The plasma vanishes long before the critical value of the electron density is reached. In contrast to what is predicted by the positive column model it is found that T e does not stay constant along the column, but monotonically increases with the distance from the microwave launcher. Increases of more than 50% over 30 cm were found.

  10. An FPGA based control unit for synchronization of laser Thomson scattering measurements to plasma events on MAST

    International Nuclear Information System (INIS)

    Naylor, G.A.

    2010-01-01

    The power and flexibility of modern Field Programmable Gate Arrays (FPGAs) is now being recognised in many areas of instrumentation and control . The high performance of modern ADCs and the high throughput of FPGAs allow the emulation of many specialised analogue instruments. The functions of heterodyne detection, phase measurements, spectrum analyzers, phase sensitive detectors, counters, etc. can be achieved in relatively simple hardware using an FPGA. The complex filtering functions can be efficiently performed digitally in the FPGA, without recourse to a separate DSP chip. This paper describes the use of a custom off the shelf FPGA board with a collection of custom interface boards to produce a powerful custom trigger system. This has been developed for agile triggering of YAG lasers on MAST. This unit allows various analogue inputs including magnetics data to be processed in real-time and allow Thomson scattering data to be collected at accurate times with respect to randomly occurring MHD phenomena such as neoclassical tearing modes (NTMs). The FPGA allows a 'System On a Chip' architecture in order to perform fast filtering in logic coupled to a dedicated soft processor for real-time fixed latency operations and a second soft processor to handle external communications with the control system for system configuration and reporting of status/archived data. The use of such a generic structure in order to provide a common approach, with reduced software development times, for diverse diagnostic situations will be discussed.

  11. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Science.gov (United States)

    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.

  12. Characterization of a material by probability of linear scattering using effect of target thickness

    International Nuclear Information System (INIS)

    Nghiep, T.D.; Khai, N.T.; Cong, N.T.; Minh, D.T.N.

    2013-01-01

    We report on an experimental test with 662 keV gamma photons scattered from a set of samples from 6 C, 13 Al, 26 Fe, 29 Cu, 47 Ag, 82 Pb and stainless steel for determination of probability of linear scattering, which can be used for characterization of a material. The results show that for the given target and scattering angle, the effect of target thickness in gamma photons scattering relates to single and multiple scattering and that the scattered events exponentially increase with an increase in target thickness and saturation at some values of thickness. The experimental results correlate with the typical function of energy transfer model. (author)

  13. Scanning differential polarization microscope: Its use to image linear and circular differential scattering

    International Nuclear Information System (INIS)

    Mickols, W.; Maestre, M.F.

    1988-01-01

    A differential polarization microscope that couples the sensitivity of single-beam measurement of circular dichroism and circular differential scattering with the simultaneous measurement of linear dichroism and linear differential scattering has been developed. The microscope uses a scanning microscope stage and single-point illumination to give the very shallow depth of field found in confocal microscopy. This microscope can operate in the confocal mode as well as in the near confocal condition that can allow one to program the coherence and spatial resolution of the microscope. This microscope has been used to study the change in the structure of chromatin during the development of sperm in Drosophila

  14. Isotopic imaging via nuclear resonance fluorescence with laser-based Thomson radiation

    Science.gov (United States)

    Barty, Christopher P. J. [Hayward, CA; Hartemann, Frederic V [San Ramon, CA; McNabb, Dennis P [Alameda, CA; Pruet, Jason A [Brentwood, CA

    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.

  15. Revisão do gênero Cyclopeplus Thomson (Coleoptera, Cerambycidae, Lamiinae, Anisocerini Revision of the genus Cyclopeplus Thomson (Coleoptera, Cerambycidae, Lamiinae, Anisocerini

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Alvarenga Júlio

    2002-12-01

    Full Text Available The genus Cyclopeplus Thomson, 1860 is revised. New synonyms proposed: C. violaceus Lane, 1957 = C. peruvianas Tippmann, 1939 and C. germaini Gounelle, 1906 = C. lacordairei Thomson, 1868. The five species of Cyclopeplus are keyed, redescribed and illustrated.

  16. Advantages of using gyrotron scattering for alpha particle diagnostics

    International Nuclear Information System (INIS)

    Woskoboinikow, P.P.; Cohn, D.R.; Machuzak, J.S.; Myer, R.C.; Rhee, R.Y.

    1987-07-01

    Millimeter-wave gyrotron collective Thomson scattering can be an effective diagnostic technique for the study of alpha particle behavior in ignited plasmas. The measurement of alpha particle density, velocity distribution, and alpha particle induced plasma instabilities can be accomplished with both spatial and temporal resolution. Advantages include long pulse operation which can make possible very high signal to noise ratios and use of millimeter waves which maximizes the Doppler shifted scattered signal in WHz -1 and makes possible scattering angles up to 180 0 . Extraordinary mode scattering at approximately 60 and 200 GHz would be used in TFTR and CIT respectively, and 140 GHz ordinary mode scattering in JET. 8 refs., 1 fig

  17. Thermodynamic Analysis of TEG-TEC Device Including Influence of Thomson Effect

    Science.gov (United States)

    Feng, Yuanli; Chen, Lingen; Meng, Fankai; Sun, Fengrui

    2018-01-01

    A thermodynamic model of a thermoelectric cooler driven by thermoelectric generator (TEG-TEC) device is established considering Thomson effect. The performance is analyzed and optimized using numerical calculation based on non-equilibrium thermodynamic theory. The influence characteristics of Thomson effect on the optimal performance and variable selection are investigated by comparing the condition with and without Thomson effect. The results show that Thomson effect degrades the performance of TEG-TEC device, it decreases the cooling capacity by 27 %, decreases the coefficient of performance (COP) by 19 %, decreases the maximum cooling temperature difference by 11 % when the ratio of thermoelectric elements number is 0.6, the cold junction temperature of thermoelectric cooler (TEC) is 285 K and the hot junction temperature of thermoelectric generator (TEG) is 450 K. Thomson effect degrades the optimal performance of TEG-TEC device, it decreases the maximum cooling capacity by 28 % and decreases the maximum COP by 28 % under the same junction temperatures. Thomson effect narrows the optimal variable range and optimal working range. In the design of the devices, limited-number thermoelectric elements should be more allocated appropriately to TEG when consider Thomson effect. The results may provide some guidelines for the design of TEG-TEC devices.

  18. Linear algebraic analyses of structures with one predominant type of anomalous scatterer

    International Nuclear Information System (INIS)

    Karle, J.

    1989-01-01

    Further studies have been made of the information content of the exact linear equations for analyzing anomalous dispersion data in one-wavelength experiments. The case of interest concerns structures containing atoms that essentially do not scatter anomalously and one type of anomalously scattering atoms. For this case, there are three alternative ways of writing the equations. The alternative sets of equations and the transformations for transforming one set into the other are given explicitly. Comparison calculations were made with different sets of equations. Isomorphous replacement information is readily introduced into the calculations and the advantage of doing so is clearly illustrated by the results. Another aspect of the potential of the exact linear algebraic theory is its application to multiple-wavelength experiments. Successful applications of the latter have been made by several collaborative groups of investigators. (orig.)

  19. On analyticity of linear waves scattered by a layered medium

    Science.gov (United States)

    Nicholls, David P.

    2017-10-01

    The scattering of linear waves by periodic structures is a crucial phenomena in many branches of applied physics and engineering. In this paper we establish rigorous analytic results necessary for the proper numerical analysis of a class of High-Order Perturbation of Surfaces methods for simulating such waves. More specifically, we prove a theorem on existence and uniqueness of solutions to a system of partial differential equations which model the interaction of linear waves with a multiply layered periodic structure in three dimensions. This result provides hypotheses under which a rigorous numerical analysis could be conducted for recent generalizations to the methods of Operator Expansions, Field Expansions, and Transformed Field Expansions.

  20. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    Energy Technology Data Exchange (ETDEWEB)

    Adamek, J., E-mail: adamek@ipp.cas.cz; Horacek, J.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R. [Institute of Plasma Physics, Prague (Czech Republic); Müller, H. W. [Max-Planck-Institute for Plasma Physics, Garching near Munich (Germany); Institute of Materials Chemistry & Research, University of Vienna, Vienna (Austria); Silva, C.; Fernandes, H.; Figueiredo, H. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S. [Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck (Austria); Kurzan, B. [Max-Planck-Institute for Plasma Physics, Garching near Munich (Germany)

    2016-04-15

    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 (Φ{sub BPP}) and the floating potential (V{sub fl}) 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 T{sub e} = (Φ{sub BPP} − V{sub fl})/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. Profile measurements of the electron temperature on the ASDEX Upgrade, COMPASS, and ISTTOK tokamak using Thomson scattering, triple, and ball-pen probes

    International Nuclear Information System (INIS)

    Adamek, J.; Horacek, J.; Bilkova, P.; Böhm, P.; Aftanas, M.; Vondracek, P.; Stöckel, J.; Panek, R.; Müller, H. W.; Silva, C.; Fernandes, H.; Figueiredo, H.; Schrittwieser, R.; Ionita, C.; Mehlmann, F.; Costea, S.; Kurzan, B.

    2016-01-01

    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 (Φ_B_P_P) and the floating potential (V_f_l) 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 T_e = (Φ_B_P_P − V_f_l)/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.

  2. Production of High Harmonic X-Ray Radiation from Non-linear Thomson at LLNL PLEIADES

    CERN Document Server

    Lim, Jae; Betts, Shawn; Crane, John; Doyuran, Adnan; Frigola, Pedro; Gibson, David J; Hartemann, Fred V; Rosenzweig, James E; Travish, Gil; Tremaine, Aaron M

    2005-01-01

    We describe an experiment for production of high harmonic x-ray radiation from Thomson backscattering of an ultra-short high power density laser by a relativistic electron beam at the PLEIADES facility at LLNL. In this scenario, electrons execute a “figure-8” motion under the influence of the high-intensity laser field, where the constant characterizing the field strength is expected to exceed unity: $aL=e*EL/m*c*ωL ≥ 1$. With large $aL$ this motion produces high harmonic x-ray radiation and significant broadening of the spectral peaks. This paper is intended to give a layout of the PLEIADES experiment, along with progress towards experimental goals.

  3. Millimeter-wave receiver design for plasma diagnostics

    DEFF Research Database (Denmark)

    Leipold, Frank; Hansen, S. K.; Jacobsen, Asger Schou

    2016-01-01

    Scattered millimeter waves entering from the collective Thomson scattering diagnostic at ASDEX Upgrade fusion device are generally elliptically polarized. In order to convert the millimeter waves to linearly polarized waves (required for the detector), birefringent window assemblies (sapphire) ha...

  4. Absorption line profiles in a moving atmosphere - A single scattering linear perturbation theory

    Science.gov (United States)

    Hays, P. B.; Abreu, V. J.

    1989-01-01

    An integral equation is derived which linearly relates Doppler perturbations in the spectrum of atmospheric absorption features to the wind system which creates them. The perturbation theory is developed using a single scattering model, which is validated against a multiple scattering calculation. The nature and basic properties of the kernels in the integral equation are examined. It is concluded that the kernels are well behaved and that wind velocity profiles can be recovered using standard inversion techniques.

  5. Thomson scattering on argon surfatron plasmas at intermediate pressures: Axial profiles of the electron temperature and electron density

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, J.M., E-mail: f02palij@gmail.co [Departamento de Fisica, Universidad de Cordoba, Campus de Rabanales, ed. C-2, 14071 Cordoba (Spain); Iordanova, E.; Veldhuizen, E.M. van; Baede, L. [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Gamero, A.; Sola, A. [Departamento de Fisica, Universidad de Cordoba, Campus de Rabanales, ed. C-2, 14071 Cordoba (Spain); Mullen, J.J.A.M. van der, E-mail: j.j.a.m.v.d.Mullen@tue.n [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Departamento de Fisica, Universidad de Cordoba, Campus de Rabanales, ed. C-2, 14071 Cordoba (Spain)

    2010-03-15

    The axial profiles of the electron density n{sub e} and electron temperature T{sub e} of argon surfatron plasmas in the pressure range of 6-20 mbar and microwave power between 32 and 82 W have been determined using Thomson Scattering of laser irradiation at 532 nm. For the electron density and temperature we found values in the ranges 5 x 10{sup 18} < n{sub e} < 8 x 10{sup 19} m{sup -3} and 1.1 < T{sub e} < 2.0 eV. Due to several improvements of the setup we could reduce the errors of n{sub e} and T{sub e} down to 8% and 3%, respectively. It is found that n{sub e} decreases in the direction of the wave propagation with a slope that is nearly constant. The slope depends on the pressure but not on the power. Just as predicted by theories we see that increasing the power leads to longer plasma columns. However, the plasmas are shorter than what is predicted by theories based on the assumption that for the plasma-wave interaction electron-atom collisions are of minor importance (the so-called collisionless regime). The plasma vanishes long before the critical value of the electron density is reached. In contrast to what is predicted by the positive column model it is found that T{sub e} does not stay constant along the column, but monotonically increases with the distance from the microwave launcher. Increases of more than 50% over 30 cm were found.

  6. Inverse scattering solution of non-linear evolution equations in one space dimension: an introduction

    International Nuclear Information System (INIS)

    Alvarez-Estrada, R.F.

    1979-01-01

    A comprehensive review of the inverse scattering solution of certain non-linear evolution equations of physical interest in one space dimension is presented. We explain in some detail the interrelated techniques which allow to linearize exactly the following equations: (1) the Korteweg and de Vries equation; (2) the non-linear Schrodinger equation; (3) the modified Korteweg and de Vries equation; (4) the Sine-Gordon equation. We concentrate in discussing the pairs of linear operators which accomplish such an exact linearization and the solution of the associated initial value problem. The application of the method to other non-linear evolution equations is reviewed very briefly

  7. Application of the method of continued fractions for electron scattering by linear molecules

    International Nuclear Information System (INIS)

    Lee, M.-T.; Iga, I.; Fujimoto, M.M.; Lara, O.; Brasilia Univ., DF

    1995-01-01

    The method of continued fractions (MCF) of Horacek and Sasakawa is adapted for the first time to study low-energy electron scattering by linear molecules. Particularly, we have calculated the reactance K-matrices for an electron scattered by hydrogen molecule and hydrogen molecular ion as well as by a polar LiH molecule in the static-exchange level. For all the applications studied herein. the calculated physical quantities converge rapidly, even for a strongly polar molecule such as LiH, to the correct values and in most cases the convergence is monotonic. Our study suggests that the MCF could be an efficient method for studying electron-molecule scattering and also photoionization of molecules. (Author)

  8. Slab albedo for linearly and quadratically anisotropic scattering kernel with modified F{sub N} method

    Energy Technology Data Exchange (ETDEWEB)

    Tuereci, R. Goekhan [Kirikkale Univ. (Turkey). Kirikkale Vocational School; Tuereci, D. [Ministry of Education, Ankara (Turkey). 75th year Anatolia High School

    2017-11-15

    One speed, time independent and homogeneous medium neutron transport equation is solved with the anisotropic scattering which includes both the linearly and the quadratically anisotropic scattering kernel. Having written Case's eigenfunctions and the orthogonality relations among of these eigenfunctions, slab albedo problem is investigated as numerically by using Modified F{sub N} method. Selected numerical results are presented in tables.

  9. Cluster explosion investigated by linearly chirped spectral scattering of an expanding plasma sphere

    International Nuclear Information System (INIS)

    Liu Jiansheng; Wang Cheng; Liu Bingchen; Shuai Bin; Wang Wentao; Cai Yi; Li Hongyu; Ni Guoquan; Li Ruxin; Xu Zhizhan

    2006-01-01

    Femtosecond explosive processes of argon clusters irradiated by linearly chirped ultraintense laser pulses have been investigated by 90 deg. side spectral scattering. The spectral redshift and blueshift, which correlate with the cluster explosion processes have been measured for negatively and positively chirped driving laser pulses, respectively. The evolution of the heated-cluster polarizability indicates that the core of the cluster is shielded from the laser field in the beginning of the explosion and enhanced scattering occurs after the fast explosion initiates. Evidence of resonant heating is found from the coincidence of enhanced scattering with enhanced absorption measured using the transmitted spectra. Anomalously large-size clusters with very low gas density have been observed in this way and can be used as clean and important cluster targets

  10. Extended Linear Embedding via Green's Operators for Analyzing Wave Scattering from Anisotropic Bodies

    Directory of Open Access Journals (Sweden)

    V. Lancellotti

    2014-01-01

    Full Text Available Linear embedding via Green’s operators (LEGO is a domain decomposition method particularly well suited for the solution of scattering and radiation problems comprised of many objects. The latter are enclosed in simple-shaped subdomains (electromagnetic bricks which are in turn described by means of scattering operators. In this paper we outline the extension of the LEGO approach to the case of penetrable objects with dyadic permittivity or permeability. Since a volume integral equation is only required to solve the scattering problem inside a brick and the scattering operators are inherently surface operators, the LEGO procedure per se can afford a reduction of the number of unknowns in the numerical solution with the Method of Moments and subsectional basis functions. Further substantial reduction is achieved with the eigencurrents expansion method (EEM which employs the eigenvectors of the scattering operator as local entire-domain basis functions over a brick’s surface. Through a few selected numerical examples we discuss the validation and the efficiency of the LEGO-EEM technique applied to clusters of anisotropic bodies.

  11. Photon scattering by the giant dipole resonance

    International Nuclear Information System (INIS)

    Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.

    1979-01-01

    Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

  12. Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1978--May 31, 1979

    International Nuclear Information System (INIS)

    York, T.M.; Klevans, E.H.

    1979-02-01

    Experimental and analytical studies of end loss from a linear theta pinch have been carried out. Analysis of reduced data on loss from a 25 cm long theta pinch has indicated: rotation at the end of pinch collapse, which appears to persist; ejection of the plasma in two modes, the first of which includes reversed, trapped fields; unique patterns of radial and axial variation of electron density in the end loss flow; substantial inaccuracies in plasma properties indicated by spectroscopy as compared to Thomson scattering. Studies of loss in a 50 cm long pinch with 50 eV, 2 x 10 16 cm -3 plasma are underway

  13. Synonymic notes on Lepidanthrax osten sacken and redescription of L. tinctus (Thomson (Diptera, Bombyliidae, Anthracinae

    Directory of Open Access Journals (Sweden)

    Carlos José Einicker Lamas

    1996-01-01

    Full Text Available Based on the analysis of types, Lepidanthrax brachialis (Thomson, 1869 and L. quinquepunclatus (Thomson, 1869 are considered junior synonyms of L. tinctus (Thomson, 1869. Notes and illustrations of the type are presented.

  14. Stress and neutron scattering measurements on linear polymer melts undergoing steady elongational flow

    DEFF Research Database (Denmark)

    Hassager, Ole; Mortensen, Kell; Bach, Anders

    2012-01-01

    We use small-angle neutron scattering to measure the molecular stretching in polystyrene melts undergoing steady elongational flow at large stretch rates. The radius of gyration of the central segment of a partly deuterated polystyrene molecule is, in the stretching direction, increasing...... exhibited by the linear polystyrene melt....

  15. Scatter fractions from linear accelerators with x-ray energies from 6 to 24 MV.

    Science.gov (United States)

    Taylor, P L; Rodgers, J E; Shobe, J

    1999-08-01

    Computation of shielding requirements for a linear accelerator must take into account the amount of radiation scattered from the patient to areas outside the primary beam. Currently, the most frequently used data are from NCRP 49 that only includes data for x-ray energies up to 6 MV and angles from 30 degrees to 135 degrees. In this work we have determined by Monte Carlo simulation the scattered fractions of dose for a wide range of energies and angles of clinical significance including 6, 10, 18, and 24 MV and scattering angles from 10 degrees to 150 degrees. Calculations were made for a 400 cm2 circular field size impinging onto a spherical phantom. Scattered fractions of dose were determined at 1 m from the phantom. Angles from 10 degrees to 30 degrees are of concern for higher energies where the scatter is primarily in the forward direction. An error in scatter fraction may result in too little secondary shielding near the junction with the primary barrier. The Monte Carlo code ITS (Version 3.0) developed at Sandia National Laboratory and NIST was used to simulate scatter from the patient to the barrier. Of significance was the variation of calculated scattered dose with depth of measurement within the barrier indicating that accurate values may be difficult to obtain. Mean energies of scatter x-ray spectra are presented.

  16. Joule-Thomson expansion of Kerr-AdS black holes

    Energy Technology Data Exchange (ETDEWEB)

    Oekcue, Oezguer; Aydiner, Ekrem [Istanbul University, Department of Physics, Faculty of Science, Istanbul (Turkey)

    2018-02-15

    In this paper, we study Joule-Thomson expansion for Kerr-AdS black holes in the extended phase space. A Joule-Thomson expansion formula of Kerr-AdS black holes is derived. We investigate both isenthalpic and numerical inversion curves in the T-P plane and demonstrate the cooling-heating regions for Kerr-AdS black holes. We also calculate the ratio between minimum inversion and critical temperatures for Kerr-AdS black holes. (orig.)

  17. Multiple Low Energy Long Bone Fractures in the Setting of Rothmund-Thomson Syndrome

    Directory of Open Access Journals (Sweden)

    Nicholas Beckmann

    2015-01-01

    Full Text Available 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.

  18. Dynamic effects on cyclotron scattering in pulsar accretion columns

    International Nuclear Information System (INIS)

    Brainerd, J.J.; Meszaros, P.

    1991-01-01

    A resonant scattering model for photon reprocessing in a pulsar accretion column is presented. The accretion column is optically thin to Thomson scattering and optically thick to resonant scattering at the cyclotron frequency. Radiation from the neutron star surface propagates freely through the column until the photon energy equals the local cyclotron frequency, at which point the radiation is scattered, much of it back toward the star. The radiation pressure in this regime is insufficient to stop the infall. Some of the scattered radiation heats the stellar surface around the base of the column, which adds a softer component to the spectrum. The partial blocking by the accretion column of X-rays from the surface produces a fan beam emission pattern. X-rays above the surface cyclotron frequency freely escape and are characterized by a pencil beam. Gravitational light bending produces a pencil beam pattern of column-scattered radiation in the antipodal direction, resulting in a strongly angle-dependent cyclotron feature. 31 refs

  19. Bobina de Thomson

    Directory of Open Access Journals (Sweden)

    Horacio Munguía Aguilar

    2014-12-01

    Full Text Available Uno de los instrumentos más didácticos en la enseñanza de las leyes del electromagnetismo es la denominada Bobina de Thomson. Con ella se pueden realizar diferentes experimentos sobre las leyes de Ampere y Faraday. En el presente trabajo se muestra su funcionamiento, se explica el mecanismo de levitación del anillo de inducción, se presenta los detalles de un modelo construido y se mencionan otros experimentos que enriquecen su funcionalidad.

  20. Prediction of Isoenthalps, Joule–Thomson Coefficients and Joule–Thomson Inversion Curves of Refrigerants by Molecular Simulation

    Czech Academy of Sciences Publication Activity Database

    Figueroa-Gerstenmaier, S.; Lísal, Martin; Nezbeda, Ivo; Smith, W.R.; Trejos, V.M.

    2014-01-01

    Roč. 375, AUG 15 (2014), s. 143-151 ISSN 0378-3812 Grant - others:NSERCC(CA) OGP-1041 Institutional support: RVO:67985858 Keywords : refrigerants * molecular simulation * Joule-Thomson Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.200, year: 2014

  1. Electrons and atoms in intense laser fields

    International Nuclear Information System (INIS)

    Davidovich, L.

    1982-11-01

    Several non-linear effects that show up when electrons and atoms interact with strong laser fields are considered. Thomson scattering, electron potential scattering in the presence of a laser beam, atomic ionization by strong laser fields, the refraction of electrons by laser beams and the Kapitza-Dirac effect are discussed. (Author) [pt

  2. Electrons and atoms in intense laser fields

    International Nuclear Information System (INIS)

    Davidovich, L.

    1982-01-01

    Several non-linear effects that show up when electrons and atoms interact with strong laser fields are considered. Thomson scattering, electron potential scattering in the presence of a laser beam, atomic ionization by strong laser fields, the refraction of electrons by laser beams and the Kapitza-Dirac effect are discussed. (Author) [pt

  3. Validation of head scatter factor for an Elekta synergy platform linear accelerator

    International Nuclear Information System (INIS)

    Johannes, N.B.

    2013-07-01

    A semi-empirical method has been proposed and developed to model and compute head or collimator scatter factors for 6 and 15 MV photon beams from Elekta Synergy platform linear accelerator at the radiation oncology centre of 'Sweden-Ghana Medical Centre Limited', East Legon Hills in Accra. The proposed model was based on two dimensional Gaussian distribution, whose output was compared to measured head scatter factor data for the linear accelerator obtained during commissioning of the teletherapy machine. The two dimensions Gaussian distribution model used physical specifications and configuration of the head unit (collimator system) of the linear accelerator, which were obtained from the user manual provided by the manufacturer of the linear accelerator. The algorithm for the model was implemented using Matlab software in the Microsoft windows environment. The model was done for both square and rectangular fields, and the output compared with corresponding measured data. The comparisons for the square fields were used to establish an error term in the Gaussian distribution function. The error term was determined by plotting the difference between the output factors from MatLab and the corresponding measured data as function of one side of a square field (equivalent square field). The correlation equation of the curve obtained was chosen as the error term, which was incorporated into the Gaussian distribution function. This was repeated for two photon beam energies (6 and 15 MV). The refined Gaussian distributions were then used to determine head scatter factors for square and rectangular fields. For the rectangular fields, Sterling's proposed formula was used to find equivalent square used to obtain the equivalent square fields found in the error terms of the proposed formula was sed to find equivalent square used to obtain the equivalent square fields found in the error terms of the proposed and developed model. The output of the 2D Gaussian distribution without

  4. A variational proof of Thomson's theorem

    Energy Technology Data Exchange (ETDEWEB)

    Fiolhais, Miguel C.N., E-mail: miguel.fiolhais@cern.ch [Department of Physics, City College of the City University of New York, 160 Convent Avenue, New York, NY 10031 (United States); Department of Physics, New York City College of Technology, 300 Jay Street, Brooklyn, NY 11201 (United States); LIP, Department of Physics, University of Coimbra, 3004-516 Coimbra (Portugal); Essén, Hanno [Department of Mechanics, Royal Institute of Technology (KTH), Stockholm SE-10044 (Sweden); Gouveia, Tomé M. [Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2016-08-12

    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.

  5. Precision measurements of linear scattering density using muon tomography

    Science.gov (United States)

    Åström, E.; Bonomi, G.; Calliari, I.; Calvini, P.; Checchia, P.; Donzella, A.; Faraci, E.; Forsberg, F.; Gonella, F.; Hu, X.; Klinger, J.; Sundqvist Ökvist, L.; Pagano, D.; Rigoni, A.; Ramous, E.; Urbani, M.; Vanini, S.; Zenoni, A.; Zumerle, G.

    2016-07-01

    We demonstrate that muon tomography can be used to precisely measure the properties of various materials. The materials which have been considered have been extracted from an experimental blast furnace, including carbon (coke) and iron oxides, for which measurements of the linear scattering density relative to the mass density have been performed with an absolute precision of 10%. We report the procedures that are used in order to obtain such precision, and a discussion is presented to address the expected performance of the technique when applied to heavier materials. The results we obtain do not depend on the specific type of material considered and therefore they can be extended to any application.

  6. Transfer by anisotropic scattering between subsets of the unit sphere of directions in linear transport theory

    International Nuclear Information System (INIS)

    Trombetti, T.

    1990-01-01

    The exact kernel method is presented for linear transport problems with azimuth-dependent angular fluxes. It is based on the evaluation of average scattering densities (ASD's) that fully describe the neutron (or particle) transfer between subsets of the unit sphere of directions by anisotropic scattering. Reciprocity and other ASD functional properties are proved and combined with the symmetry properties of suitable SN quadrature sets. This greatly reduces the number of independent ASD's to be computed and stored. An approach for performing ASD computations with reciprocity checks is presented. ASD expressions of the scattering source for typical 2D geometries are explicitly given. (author)

  7. Comparison in electron density distribution of tokamak plasma between ruby-laser scattering and milli-meter wave interferometric measurements

    International Nuclear Information System (INIS)

    Matoba, Tohru; Funahashi, Akimasa; Itagaki, Tokiyoshi; Takahashi, Koki; Kumagai, Katsuaki

    1976-08-01

    The electron density in JFT-2 tokamak has been measured by two methods, i.e. Thomson scattering of ruby-laser light and interferometry of millimeter wave. Two-dimensional distribution of the scattered light intensities were obtained by scattering measurement; absolute calibration was made by normalizing the scattered intensities with the averaged density determined from interferometric measurement. The horizontal density distributions in laser scattering were compared with those in from the averaged densities measured with a 4-mm interferometer through inverse-transformation. Agreement is good between the two measurements, except where they give erroneous data because of irreproducibility of the discharge. (auth.)

  8. Variation of linear and circular polarization persistence for changing field of view and collection area in a forward scattering environment

    Science.gov (United States)

    van der Laan, John D.; Wright, Jeremy B.; Scrymgeour, David A.; Kemme, Shanalyn A.; Dereniak, Eustace L.

    2016-05-01

    We present experimental and simulation results for a laboratory-based forward-scattering environment, where 1 μm diameter polystyrene spheres are suspended in water to model the optical scattering properties of fog. Circular polarization maintains its degree of polarization better than linear polarization as the optical thickness of the scattering environment increases. Both simulation and experiment quantify circular polarization's superior persistence, compared to that of linear polarization, and show that it is much less affected by variations in the field of view and collection area of the optical system. Our experimental environment's lateral extent was physically finite, causing a significant difference between measured and simulated degree of polarization values for incident linearly polarized light, but not for circularly polarized light. Through simulation we demonstrate that circular polarization is less susceptible to the finite environmental extent as well as the collection optic's limiting configuration.

  9. The possibilities of laser scattering diagnostics in plasmas

    International Nuclear Information System (INIS)

    Doebele, H.F.

    1974-01-01

    The laser has opened many new possibilities for plasma diagnostics. Intensive monochromatic light sources with higher precision and better time resolution have helped to improve such well-known techniques as interferometry and Schlieren method. At the same time, the range of applicability was extended into the infrared range. Due to the wave length dependence of the plasma diffraction index, the effects increase approximately lambda in interferometry and approximately lambda 2 in the Schlieren methods. The laser also helped to develop entirely new methods such as utilization of the Faraday effect in the electrons of a plasma in a magnetic field which allows the calculation of the product nsub(e) x B from the rotation of the polarization plane of monochromatic light with linear polarization. Here, too, the effect increases approximately lambda 2 , and measurements have been carried out up to FIR (HCN,337 μ). The best diagnostic possibilities are offered by the Thomson scattering diagnostics. Electron and ion temperatures, electron densities, drift velocities, magnetic fields, wave propagation and dissipation can be measured by this method. (orig./AK) [de

  10. Scattering of massless lumps and non-local charges in the two-dimensional classical non-linear sigma-model

    International Nuclear Information System (INIS)

    Luescher, M.; Pohlmeyer, K.

    1977-09-01

    Finite energy solutions of the field equations of the non-linear sigma-model are shown to decay asymptotically into massless lumps. By means of a linear eigenvalue problem connected with the field equations we then find an infinite set of dynamical conserved charges. They, however, do not provide sufficient information to decode the complicated scattering of lumps. (orig.) [de

  11. On velocity space interrogation regions of fast-ion collective Thomson scattering at ITER

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nielsen, Stefan Kragh; Bindslev, Henrik

    2011-01-01

    the collective scattering in well-defined regions in velocity space, here dubbed interrogation regions. Since the CTS instrument measures entire spectra of scattered radiation, many different interrogation regions are probed simultaneously. We here give analytic expressions for weight functions describing...... the interrogation regions, and we show typical interrogation regions of the proposed ITER CTS system. The backscattering system with receivers on the low-field side is sensitive to fast ions with pitch |p| = |v/v| ... scattering system with receivers on the high-field side would be sensitive to co- and counter-passing fast ions in narrow interrogation regions with pitch |p| > 0.6–0.8. Additionally, we use weight functions to reconstruct 2D fast-ion distribution functions, given two projected 1D velocity distribution...

  12. Combining linear polarization spectroscopy and the Representative Layer Theory to measure the Beer-Lambert law absorbance of highly scattering materials.

    Science.gov (United States)

    Gobrecht, Alexia; Bendoula, Ryad; Roger, Jean-Michel; Bellon-Maurel, Véronique

    2015-01-01

    Visible and Near Infrared (Vis-NIR) Spectroscopy is a powerful non destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in-line in industries, in-vivo with biomedical applications or in-field for agricultural and environmental applications. However, highly scattering samples subvert Beer-Lambert law's linear relationship between spectral absorbance and the concentrations. Instead of spectral pre-processing, which is commonly used by Vis-NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, based on Polarized Light Spectroscopy to improve the absorbance signal measurement on highly scattering samples. This method selects part of the signal which is less impacted by scattering. The resulted signal is combined in the Absorption/Remission function defined in Dahm's Representative Layer Theory to compute an absorbance signal fulfilling Beer-Lambert's law, i.e. being linearly related to concentration of the chemicals composing the sample. The underpinning theories have been experimentally evaluated on scattering samples in liquid form and in powdered form. The method produced more accurate spectra and the Pearson's coefficient assessing the linearity between the absorbance spectra and the concentration of the added dye improved from 0.94 to 0.99 for liquid samples and 0.84-0.97 for powdered samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Predicted precision of ion temperature and impurity fractional density measurements using the JET collective scattering diagnostic

    International Nuclear Information System (INIS)

    Orsitto, F.

    1992-11-01

    In a previous investigation the possibility of measuring the bulk ion temperature was considered in detail, in the context of the proposed Thomson scattering diagnostic for fast ions and alpha particles in the Joint European Torus project. In this report we give an affirmative answer to the question of whether good precision can be obtained in the simultaneous determination of the temperatures and densities of plasma ions from a collective scattering experiment provided some conditions are satisfied. (Author)

  14. Half-space albedo problem with modified F{sub N} method for linear and quadratic anisotropic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Tuereci, R.G. [Kirikkale Univ., Kirikkale (Turkey). Kirikkale Vocational School; Tuereci, D. [Ministry of Education, Ankara (Turkey). 75th year Anatolia High School

    2017-05-15

    One speed, time independent and homogeneous medium neutron transport equation can be solved with the anisotropic scattering which includes both the linear anisotropic and the quadratic anisotropic scattering properties. Having solved Case's eigenfunctions and the orthogonality relations among these eigenfunctions, some neutron transport problems such as albedo problem can be calculated as numerically by using numerical or semi-analytic methods. In this study the half-space albedo problem is investigated by using the modified F{sub N} method.

  15. Rothmund-thomson Syndrome

    Directory of Open Access Journals (Sweden)

    M Z Mani

    1979-01-01

    Full Text Available A case of Rothmund-Thomson syndrome in an 8-year-old Indian male is reported. The patient had bilaterally symmertrical superficial pigmentary deposition of thin nebulae in the lower one-third of the cornea and oonjunctiva. Urinary togmphy rcvmw a dibasic aininoacid with excretion of arginine, lysine;.hmncicystine and glycine. Other features of interest in this patient were onset at the age of 8 days and start of the disease on the hands and feet rather than face. The patient also developed repeated ulcerations on the hands and feet subsequent to minor trauma.

  16. Rothmund-Thomson Syndrome

    DEFF Research Database (Denmark)

    Suter, Aude-Annick; Itin, Peter; Heinimann, Karl

    2016-01-01

    with neutropenia (PN) and Dyskeratosis Congenita (DC), poikiloderma occurs as one of the main symptoms. Here, we report on genotype and phenotype data of a cohort of 44 index patients with RTS or related genodermatoses. METHODS: DNA samples from 43 patients were screened for variants in the 21 exons of the RECQL4...... to assess the patients' cancer risk, to avoid continuous and inconclusive clinical evaluations and to clarify the recurrence risk in the families. Additionally, it shows that the phenotype of more than 50% of the patients with suspected Rothmund-Thomson disease may be due to mutations in other genes raising...

  17. Application of Thomson scattering at 1.06μm as a diagnostic for spatial profile measurements of electron temperature and density on the TCV tokamak

    International Nuclear Information System (INIS)

    Franke, S.

    1997-04-01

    The variable configuration tokamak, TCV, in operation at CRPP since the end of 1991, is a particularly challenging machine with regard to the experimental system that must provide essential information regarding properties of confined plasmas with strongly shaped, non-circular cross-sections. The importance of the energy confinement issue in a machine designed specifically for the investigation of the effect of plasma shape on confinement and stability is self-evident, as is the necessity for a diagnostic capable of providing the profiles of electron temperature and density required for evaluation of this confinement. For TCV, a comprehensive Thomson Scattering (TS) diagnostic was the natural choice, specifically owing to the resulting spatially localized and time resolved measurement. The details of the system installed on TCV, together with the results obtained from the diagnostic comprise the subject matter of this thesis. A first version of the diagnostic was equipped with only ten observation volumes. In this case, adequate spatial resolution can only be maintained if measurements are limited to plasmas located in the upper half of the highly elongated TCV vacuum vessel. The system has recently been upgraded through the addition of a further fifteen observation volumes, together with major technical improvements in the scattered light detection system. This new version now permits TS observations in all TCV plasma configurations, including equilibria produced in the lower and upper halves of the vacuum vessel and the highly elongated plasmas now routinely created. Whilst a description of the new detection system along with some results obtained using the extended set of observation volumes are included, this thesis reports principally on the hardware details of and the interpretation of data from the original, ten observation volume system. (author) figs., tabs., 75 refs

  18. Experimental study of TJ-1 plasma using scattering and radiation emission techniques; Analisis experimental del plasma TJ-1 con tecnicas de scattering y emision de radiacion

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, C; Zurro, B

    1987-07-01

    The Thomson scattering system of TJ-1 is described in detail. The radial profiles of Te and ne obtained in TJ-1 discharges are presented. This data make possible to deduce characteristic parameters of the plasma confinement in this machine, as energy confinement times, Zeff B. Using also radiation measurements (global and in the visible range) we obtained the particle confinement time and Zeff without non experimental assumptions. (Author) 52 refs.

  19. Polarizer design for millimeter-wave plasma diagnostics

    DEFF Research Database (Denmark)

    Leipold, Frank; Salewski, Mirko; Jacobsen, Asger Schou

    2013-01-01

    Radiation from magnetized plasmas is in general elliptically polarized. In order to convert the elliptical polarization to linear polarization, mirrors with grooved surfaces are currently employed in our collective Thomson scattering diagnostic at ASDEX Upgrade. If these mirrors can be substituted...

  20. Compton scattering from nuclei and photo-absorption sum rules

    International Nuclear Information System (INIS)

    Gorchtein, Mikhail; Hobbs, Timothy; Londergan, J. Timothy; Szczepaniak, Adam P.

    2011-01-01

    We revisit the photo-absorption sum rule for real Compton scattering from the proton and from nuclear targets. In analogy with the Thomas-Reiche-Kuhn sum rule appropriate at low energies, we propose a new 'constituent quark model' sum rule that relates the integrated strength of hadronic resonances to the scattering amplitude on constituent quarks. We study the constituent quark model sum rule for several nuclear targets. In addition, we extract the α=0 pole contribution for both proton and nuclei. Using the modern high-energy proton data, we find that the α=0 pole contribution differs significantly from the Thomson term, in contrast with the original findings by Damashek and Gilman.

  1. The effects of different expansions of the exit distribution on the extrapolation length for linearly anisotropic scattering

    International Nuclear Information System (INIS)

    Bulut, S.; Guelecyuez, M.C.; Kaskas, A.; Tezcan, C.

    2007-01-01

    H N and singular eigenfunction methods are used to determine the neutron distribution everywhere in a source-free half space with zero incident flux for a linearly anisotropic scattering kernel. The singular eigenfunction expansion of the method of elementary solutions is used. The orthogonality relations of the discrete and continuous eigenfunctions for linearly anisotropic scattering provides the determination of the expansion coefficients. Different expansions of the exit distribution are used: the expansion in powers of μ, the expansion in terms of Legendre polynomials and the expansion in powers of 1/(1+μ). The results are compared to each other. In the second part of our work, the transport equation and the infinite medium Green function are used. The numerical results of the extrapolation length obtained for the different expansions is discussed. (orig.)

  2. Moeller scattering polarimetry for high energy e sup + e sup - linear colliders

    CERN Document Server

    Alexander, G

    2002-01-01

    The general features of the Moeller scattering and its use as an electron polarimeter are described and studied in view of the planned future high energy e sup + e sup - linear colliders. In particular the study concentrates on the TESLA collider which is planned to operate with longitudinal polarised beams at a centre of mass energy of the order of 0.5 TeV with a luminosity of 3.4x10 sup 3 sup 4 cm sup - sup 2 s sup - sup 1.

  3. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Braicovich, L., E-mail: lucio.braicovich@polimi.it; Minola, M.; Dellea, G.; Ghiringhelli, G. [CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo Da Vinci 32, Milano I-20133 (Italy); Le Tacon, M. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043 (France); Supruangnet, R. [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand)

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  4. Magnetic corrections to π -π scattering lengths in the linear sigma model

    Science.gov (United States)

    Loewe, M.; Monje, L.; Zamora, R.

    2018-03-01

    In this article, we consider the magnetic corrections to π -π scattering lengths in the frame of the linear sigma model. For this, we consider all the one-loop corrections in the s , t , and u channels, associated to the insertion of a Schwinger propagator for charged pions, working in the region of small values of the magnetic field. Our calculation relies on an appropriate expansion for the propagator. It turns out that the leading scattering length, l =0 in the S channel, increases for an increasing value of the magnetic field, in the isospin I =2 case, whereas the opposite effect is found for the I =0 case. The isospin symmetry is valid because the insertion of the magnetic field occurs through the absolute value of the electric charges. The channel I =1 does not receive any corrections. These results, for the channels I =0 and I =2 , are opposite with respect to the thermal corrections found previously in the literature.

  5. Atomic form factors, incoherent scattering functions, and photon scattering cross sections

    International Nuclear Information System (INIS)

    Hubbell, J.H.; Veigele, W.J.; Briggs, E.A.; Brown, R.T.; Cromer, D.T.; Howerton, R.J.

    1975-01-01

    Tabulations are presented of the atomic form factor, F (α,Z), and the incoherent scattering function, S (x,Z), for values of x (=sin theta/2)/lambda) from 0.005 A -1 to 10 9 A -1 , for all elements A=1 to 100. These tables are constructed from available state-of-the-art theoretical data, including the Pirenne formulas for Z=1, configuration-into action results by Brown using Brown-Fontana and Weiss correlated wavefunctions for Z=2 to 6 non-relativistic Hartree-Fock results by Cromer for Z=7 to 100 and a relativistic K-shell analytic expression for F (x,Z) by Bethe Levinger for x>10 A -1 for all elements Z=2 to 100. These tabulated values are graphically compared with available photon scattering angular distribution measurements. Tables of coherent (Rayleigh) and incoherent (Compton) total scattering cross sections obtained by nummerical integration over combinations of F 2 (x,Z) with the Thomson formula and S (x,Z) with the Klum-Nishina Formual, respectively, are presented for all elements Z=1 to 100, for photon energies 100 eV (lambda=124 A) to 100 MeV (0.000124 A). The incoherent scattering cross sections also include the radiative and double-Compton corrections as given by Mork. Similar tables are presented for the special cases of terminally-bonded hydrogen and for the H 2 molecule, interpolated and extrapolated from values calculated by Stewart et al., and by Bentley and Stewart using Kolos-Roothaan wavefunctions

  6. Linear estimates of structure functions from deep inelastic lepton-nucleon scattering data. Part 1

    International Nuclear Information System (INIS)

    Anikeev, V.B.; Zhigunov, V.P.

    1991-01-01

    This paper concerns the linear estimation of structure functions from muon(electron)-nucleon scattering. The expressions obtained for the structure functions estimate provide correct analysis of the random error and the bias The bias arises because of the finite number of experimental data and the finite resolution of experiment. The approach suggested may become useful for data handling from experiments at HERA. 9 refs

  7. Stimulated Raman scattering and ion dynamics: the role of Langmuir wave non-linearities

    International Nuclear Information System (INIS)

    Bonnaud, G.; Pesme, D.

    1988-02-01

    The non-linear evolution of stimulated Raman scattering by coupling of the SRS-driven Langmuir waves to ion acoustic waves is studied numerically, in a homogeneous density laser-irradiated plasma. The coupled wave amplitude behaviour is represented either by envelope equations or by complete wave-like equations. The various physical phenomena which are involved are described. This preliminary work has been presented at the 17th Anomalous Absorption Conference, held in last May, in Lake Tahoe City (USA) [fr

  8. Disappearance of the laue spots of the downward X-ray diffraction and huge recoil Thomson scattering in solid helium as some prominent peculiarities of a quantum crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Tetsuo

    1996-02-01

    In topographs of the downward X-ray diffraction, no Laue spots could be observed using a horizontally thin line-focussed beam. The disappearance of the Laue spots by the downward X-ray diffraction could be explained by two main factors besides a synergistic effect of the smallness of the atomic-scattering factors, the absorption coefficients, the densities etc. One is that the downward X-ray diffraction is completely inelastic scattering, and, as a result, diffracted X-ray beams may become entirely diffuse scattering. The other is that the great difference in the linear scatterer density between the forward and downward directions resulted from the fact that the irradiation of a line-focussed X-ray beam to take section topographs weakens the downward X-ray diffraction. The main reason is not due to the zero-point vibration. (J.P.N.).

  9. Disappearance of the laue spots of the downward X-ray diffraction and huge recoil Thomson scattering in solid helium as some prominent peculiarities of a quantum crystal

    International Nuclear Information System (INIS)

    Nakajima, Tetsuo.

    1996-02-01

    In topographs of the downward X-ray diffraction, no Laue spots could be observed using a horizontally thin line-focussed beam. The disappearance of the Laue spots by the downward X-ray diffraction could be explained by two main factors besides a synergistic effect of the smallness of the atomic-scattering factors, the absorption coefficients, the densities etc. One is that the downward X-ray diffraction is completely inelastic scattering, and, as a result, diffracted X-ray beams may become entirely diffuse scattering. The other is that the great difference in the linear scatterer density between the forward and downward directions resulted from the fact that the irradiation of a line-focussed X-ray beam to take section topographs weakens the downward X-ray diffraction. The main reason is not due to the zero-point vibration. (J.P.N.)

  10. Experimental study of TJ-1 plasma using scattering and radiation emission techniques

    International Nuclear Information System (INIS)

    Pardo, C.; Zurro, B.

    1987-01-01

    The Thomson scattering system of TJ-1 is described in detail. The radial profiles of Te and ne obtained in TJ-1 discharges are presented. This data make possible to deduce characteristic parameters of the plasma confinement in this machine, as energy confinement times, Zeff B. Using also radiation measurements (global and in the visible range) we obtained the particle confinement time and Zeff without non experimental assumptions. (Author) 52 refs

  11. A silicon avalanche photodiode detector circuit for Nd:YAG laser scattering

    International Nuclear Information System (INIS)

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

    1990-06-01

    A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge sensitive preamplifier has been developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N = 1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low frequency background light component. The background signal is amplified with a computer controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Z eff measurements of the plasma. The signal processing has been analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis. 4 refs., 5 figs

  12. Thomson, his discovery of the electron and the twentieth century science and technology

    International Nuclear Information System (INIS)

    Ahmad, N.

    1997-01-01

    Sir J. J. Thomson was the first to discover a subatomic particle i. e. electron. Due to this discovery he is remembered in the history as T he Atom Smasher . He was a great experimentalists and a devoted physicist. He himself, his son and his seven pupils earned Noble prizes on the basis of their scientific discoveries. The discovery of electron by Sir Thomson in 1897, at Cavendish Laboratory, has rewritten the entire physical science. Although electron has wide spread applications in almost every field, yet its exact nature is not fully known. This article briefly describes the life of Sir Thomson, his achievements and the impact of his discovery of electron on the twentieth century science and technology. (author)

  13. Nuclear resonant scattering measurements on (57)Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector.

    Science.gov (United States)

    Kishimoto, S; Mitsui, T; Haruki, R; Yoda, Y; Taniguchi, T; Shimazaki, S; Ikeno, M; Saito, M; Tanaka, M

    2014-11-01

    We developed a silicon avalanche photodiode (Si-APD) linear-array detector for use in nuclear resonant scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 × 200 μm(2)) with a pixel pitch of 150 μm and depletion depth of 10 μm. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >10(7) cps per pixel. High-performance integrated circuits achieve multichannel scaling over 1024 continuous time bins with a 1 ns resolution for each pixel without dead time. The multichannel scaling method enabled us to record a time spectrum of the 14.4 keV nuclear radiation at each pixel with a time resolution of 1.4 ns (FWHM). This method was successfully applied to nuclear forward scattering and nuclear small-angle scattering on (57)Fe.

  14. Measurements of ionic structure in shock compressed lithium hydride from ultrafast x-ray Thomson scattering.

    Science.gov (United States)

    Kritcher, A L; Neumayer, P; Brown, C R D; Davis, P; Döppner, 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; Wünsch, K; Glenzer, S H

    2009-12-11

    We present the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. 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 data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for the screening of ion-ion interactions.

  15. Scattered fractions of dose from 18 and 25 MV X-ray radiotherapy linear accelerators

    International Nuclear Information System (INIS)

    Shobe, J.; Rodgers, J.E.; Taylor, P.L.; Jackson, J.; Popescu, G.

    1996-01-01

    Over the years, measurements have been made at a few energies to estimate the scattered fraction of dose from the patient in medical radiotherapy operations. This information has been a useful aid in the determination of shielding requirements for these facilities. With these measurements, known characteriztics of photons, and various other known parameters, Monte Carlo codes are being used to calculate the scattered fractions and hence the shielding requirements for the photons of other energies commonly used in radiotherapeutic applications. The National Institute of Standards and Technology (NIST) acquired a Sagittaire medical linear accelerator (linac) which was previously located at the Yale-New Haven Hospital. This linac provides an X-ray beam of 25 MV photons and electron beams with energies up to 32 MeV. The housing on the gantry was permanently removed from the accelerator during installation. A Varian Clinac 1800 linear accelerator was used to produce the 18 MV photons at the Frederick Memorial Hospital Regional Cancer Therapy Center in Frederick, MD. This paper represents a study of the photon dose scattered from a patient in typical radiation treatment situations as it relates to the dose delivered at the isocenter in water. The results of these measurements will be compared to Monte Carlo calculations. Photon spectral measurements were not made at this time. Neutron spectral measurements were made on this Sagittaire machine in its previous location and that work was not repeated here, although a brief study of the neutron component of the 18 and 25 MV linacs was performed utilizing thermoluminescent dosimetry (TLD) to determine the isotropy of the neutron dose. (author)

  16. Edge profile analysis of Joint European Torus (JET) Thomson scattering data: Quantifying the systematic error due to edge localised mode synchronisation.

    Science.gov (United States)

    Leyland, M J; Beurskens, M N A; Flanagan, J C; Frassinetti, L; Gibson, K J; Kempenaars, M; Maslov, M; Scannell, R

    2016-01-01

    The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Localised Modes (ELMs), characterised by a periodic collapse of the steep gradient region. A common method to extract the pedestal width, gradient, and height, used on numerous machines, is by performing a modified hyperbolic tangent (mtanh) fit to overlaid profiles selected from the same region of the ELM cycle. This process of overlaying profiles, termed ELM synchronisation, maximises the number of data points defining the pedestal region for a given phase of the ELM cycle. When fitting to HRTS profiles, it is necessary to incorporate the diagnostic radial instrument function, particularly important when considering the pedestal width. A deconvolved fit is determined by a forward convolution method requiring knowledge of only the instrument function and profiles. The systematic error due to the deconvolution technique incorporated into the JET pedestal fitting tool has been documented by Frassinetti et al. [Rev. Sci. Instrum. 83, 013506 (2012)]. This paper seeks to understand and quantify the systematic error introduced to the pedestal width due to ELM synchronisation. Synthetic profiles, generated with error bars and point-to-point variation characteristic of real HRTS profiles, are used to evaluate the deviation from the underlying pedestal width. We find on JET that the ELM synchronisation systematic error is negligible in comparison to the statistical error when assuming ten overlaid profiles (typical for a pre-ELM fit to HRTS profiles). This confirms that fitting a mtanh to ELM synchronised profiles is a robust and practical technique for extracting the pedestal structure.

  17. EDITORIAL: J J Thomson's Electron

    Science.gov (United States)

    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 from the theoreticians

  18. Miniature Joule-Thomson cryocooling principles and practice

    CERN Document Server

    Maytal, Ben-Zion

    2013-01-01

    This book is the first in English being entirely dedicated to Miniature Joule-Thomson Cryocooling. The category of Joule-Thomson (JT) cryocoolers takes us back to the roots of cryogenics, in 1895, with figures like Linde and Hampson. The "cold finger" of these cryocoolers is compact, lacks moving parts, and sustains a large heat flux extraction at a steady temperature. Potentially, they cool down unbeatably fast. For example, cooling to below 100 K (minus 173 Celsius) might be accomplished within only a few seconds by liquefying argon. A level of about 120 K can be reached almost instantly with krypton. Indeed, the species of coolant plays a central role dictating the size, the intensity and the level of cryocooling. It is the JT effect that drives these cryocoolers and reflects the deviation of the "real" gas from the ideal gas properties. The nine chapters of the book are arranged in five parts. • The Common Principle of Cyrocoolers shared across the broad variety of cryocooler types • Theoretical Aspec...

  19. Modification of the collective Thomson scattering radiometer in the search for parametric decay on TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Salewski, Mirko; Bongers, W.

    2012-01-01

    Strong scattering of high-power millimeter waves at 140 GHz has been shown to take place in heating and current-drive experiments at TEXTOR when a tearing mode is present in the plasma. The scattering signal is at present supposed to be generated by the parametric decay instability. Here we descr...

  20. Proposal for a new Thomson scattering technique for large fusion devices

    International Nuclear Information System (INIS)

    Salzmann, H.; Hirsch, K.

    1982-11-01

    The application of 180 0 scattering using ultrashort laser pulses is proposed. Spatial resolution along the laser beam is achieved by high-speed detection allowing time-of-flight measurements. This LIDAR technique uses a minimum number of window ports, reduces drastically the number of optical components in the vicinity of the discharge vessel and makes remote control unnecessary. As an example the performance of such a system is discussed on the basis of available laser and detection technology for the JET geometry. (orig.)

  1. Thomson Reuters to release Book Citation Index later this year

    Science.gov (United States)

    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.

  2. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    Science.gov (United States)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-07-01

    Both the semi-classical and quantum transport properties of F-doped SnO2 thick films (˜1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ˜90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  3. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    International Nuclear Information System (INIS)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-01-01

    Both the semi-classical and quantum transport properties of F-doped SnO 2 thick films (∼1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ∼90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO 2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  4. Light Scattering Study of Mixed Micelles Made from Elastin-Like Polypeptide Linear Chains and Trimers

    Science.gov (United States)

    Terrano, Daniel; Tsuper, Ilona; Maraschky, Adam; Holland, Nolan; Streletzky, Kiril

    Temperature sensitive nanoparticles were generated from a construct (H20F) of three chains of elastin-like polypeptides (ELP) linked to a negatively charged foldon domain. This ELP system was mixed at different ratios with linear chains of ELP (H40L) which lacks the foldon domain. The mixed system is soluble at room temperature and at a transition temperature (Tt) will form swollen micelles with the hydrophobic linear chains hidden inside. This system was studied using depolarized dynamic light scattering (DDLS) and static light scattering (SLS) to determine the size, shape, and internal structure of the mixed micelles. The mixed micelle in equal parts of H20F and H40L show a constant apparent hydrodynamic radius of 40-45 nm at the concentration window from 25:25 to 60:60 uM (1:1 ratio). At a fixed 50 uM concentration of the H20F, varying H40L concentration from 5 to 80 uM resulted in a linear growth in the hydrodynamic radius from about 11 to about 62 nm, along with a 1000-fold increase in VH signal. A possible simple model explaining the growth of the swollen micelles is considered. Lastly, the VH signal can indicate elongation in the geometry of the particle or could possibly be a result from anisotropic properties from the core of the micelle. SLS was used to study the molecular weight, and the radius of gyration of the micelle to help identify the structure and morphology of mixed micelles and the tangible cause of the VH signal.

  5. Periodic Thomson scattering diagnostic with 16 spatial channels on ASDEX

    International Nuclear Information System (INIS)

    Meisel, D.; Murmann, H.; Roehr, H.; Steuer, K.H.; Becker, G.; Bosch, H.S.; Brocken, H.; Eberhagen, A.; Fussmann, G.; Gehre, O.; Gernhardt, J.; Gierke, G. v.; Glock, E.; Gruber, O.; Haas, G.; Hofmann, J.; Janeschitz, G.; Karger, F.; Klueber, O.; Kornherr, M.; Lackner, K.; Lenoci, M.; Lisitano, G.; Mast, F.; Mayer, H.M.; McCormick, K.; Mertens, V.; Niedermeyer, H.; Poschenrieder, W.; Rapp, H.; Roth, J.; Schneider, F.; Setzensack, C.; Siller, G.; Soeldner, F.X.; Wagner, F.; Zasche, D.; Izvozchikov, A.; Ryter, F.

    1986-01-01

    The Nd-YAG Periodic Scattering System (PSS) was developped in teamwork with IPF of Stuttgart-University. At first a PSS with only one spatial channel was successfully tested in the ASDEX-Tokamak in 1982. Subsequently an upgraded system with 16 spatial channels was constructed. This new system is capable of measuring Te, Ne-profiles at 17 ms intervals during the entire ASDEX-Tokamak-discharge. The PSS has been working successfully for the last one and a half years as a standard diagnostic method in the ASDEX-Tokamak. This means, that the measurement is being automatically performed during all plasma-discharges. The Te- and Ne-values are stored in the ASDEX-computer and every user has the possibility to get the Te(r, t), Ne(r, t)-data for his own needs. (orig.)

  6. Joseph John Thomson's models of matter and radiation in the early 1890s.

    Science.gov (United States)

    Bordoni, Stefano

    In the late nineteenth century, Joseph John Thomson moved away from Maxwell's specific theoretical models of matter and energy, even though he continued to rely on the general framework of Maxwell's electromagnetic theory. In his 1893 book, he accomplished the conceptual drift towards a discrete model for matter, electricity, and fields. In Thomson's model, energy was linked to tubes of force, in particular to the aether contained in them and surrounding them: the energy was the kinetic energy of aether, of both a rotational and translational kind. Starting from Maxwell's electromagnetic fields, namely stresses propagating through a continuous solid medium, Thomson arrived at a representation of fields as a sea of discrete units carrying energy and momentum. He tried to transform Maxwell's theory into a unified picture in which atomic models of matter stood beside atomic models of fields. In 1904 his interpretation of X-rays was based on the integration between two complementary features of electromagnetic radiation, the continuity and the discreteness, and on some kind of fibrous aether. In recent secondary literature, the problematic conceptual link between J. J. Thomson's theory and contemporary theories on electromagnetic radiation has been underestimated. On the contrary, in the first half of the twentieth century, some physicists inquired into that link, and a widespread debate emerged, misunderstandings included.

  7. Tokamak T-10 multipulse laser scattering: Instrumentation modernization

    International Nuclear Information System (INIS)

    Baukov, V.A.; Ponomarev, A.V.; Gorshkov, A.V.; Rossikhin, B.A.; Sannikov, V.V.; Grek, B.

    1994-01-01

    The modernized Thomson scattering diagnostic complex of Tokamak T-10 is described. The complex is based on a high-power neodimium laser. Both the laser fundamental and second harmonics serve to find out the time-dependence of plasma electron temperature and density profiles, as well as to measure the electron distribution function. One detected the scattered laser radiation at θ = 90 degrees and 2.5 degrees angles. The new-version Nd laser generates eight-pulse sequences. The laser radiation energy is E o = 30-50 J/pulse. The radiation divergence was smaller than var-phi = 0.15 mrad. The multiple radiation parameters were found to be very stable. The operator could vary the inter-pulse time intervals within the pulse sequence. The second-harmonic radiation energy was E 2 = 10-15 J/pulse. The data acquisition and analysis system was supported by IBM/AT and Macintosh computers. 6 refs., 1 fig

  8. An Account of ... William Cullen: John Thomson and the Making of a Medical Biography.

    Science.gov (United States)

    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.

  9. Psühhofüsioloogilised mängud / Kaivo Thomson

    Index Scriptorium Estoniae

    Thomson, Kaivo, 1956-

    2002-01-01

    Rmt.: Thomson, Kaivo. Psühhofüsioloogilised mängud : teooria & värvitoonide, helikõrguste ja liikumiskiiruste eristamisvõime testimine ning arendamine meetodiga "WinPsycho 2000" (CD-1). Tartu : Atlex, 2001.

  10. Linear triangle finite element formulation for multigroup neutron transport analysis with anisotropic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lillie, R.A.; Robinson, J.C.

    1976-05-01

    The discrete ordinates method is the most powerful and generally used deterministic method to obtain approximate solutions of the Boltzmann transport equation. A finite element formulation, utilizing a canonical form of the transport equation, is here developed to obtain both integral and pointwise solutions to neutron transport problems. The formulation is based on the use of linear triangles. A general treatment of anisotropic scattering is included by employing discrete ordinates-like approximations. In addition, multigroup source outer iteration techniques are employed to perform group-dependent calculations. The ability of the formulation to reduce substantially ray effects and its ability to perform streaming calculations are demonstrated by analyzing a series of test problems. The anisotropic scattering and multigroup treatments used in the development of the formulation are verified by a number of one-dimensional comparisons. These comparisons also demonstrate the relative accuracy of the formulation in predicting integral parameters. The applicability of the formulation to nonorthogonal planar geometries is demonstrated by analyzing a hexagonal-type lattice. A small, high-leakage reactor model is analyzed to investigate the effects of varying both the spatial mesh and order of angular quadrature. This analysis reveals that these effects are more pronounced in the present formulation than in other conventional formulations. However, the insignificance of these effects is demonstrated by analyzing a realistic reactor configuration. In addition, this final analysis illustrates the importance of incorporating anisotropic scattering into the finite element formulation. 8 tables, 29 figures.

  11. Linear triangle finite element formulation for multigroup neutron transport analysis with anisotropic scattering

    International Nuclear Information System (INIS)

    Lillie, R.A.; Robinson, J.C.

    1976-05-01

    The discrete ordinates method is the most powerful and generally used deterministic method to obtain approximate solutions of the Boltzmann transport equation. A finite element formulation, utilizing a canonical form of the transport equation, is here developed to obtain both integral and pointwise solutions to neutron transport problems. The formulation is based on the use of linear triangles. A general treatment of anisotropic scattering is included by employing discrete ordinates-like approximations. In addition, multigroup source outer iteration techniques are employed to perform group-dependent calculations. The ability of the formulation to reduce substantially ray effects and its ability to perform streaming calculations are demonstrated by analyzing a series of test problems. The anisotropic scattering and multigroup treatments used in the development of the formulation are verified by a number of one-dimensional comparisons. These comparisons also demonstrate the relative accuracy of the formulation in predicting integral parameters. The applicability of the formulation to nonorthogonal planar geometries is demonstrated by analyzing a hexagonal-type lattice. A small, high-leakage reactor model is analyzed to investigate the effects of varying both the spatial mesh and order of angular quadrature. This analysis reveals that these effects are more pronounced in the present formulation than in other conventional formulations. However, the insignificance of these effects is demonstrated by analyzing a realistic reactor configuration. In addition, this final analysis illustrates the importance of incorporating anisotropic scattering into the finite element formulation. 8 tables, 29 figures

  12. Modeling classical and quantum radiation from laser-plasma accelerators

    Directory of Open Access Journals (Sweden)

    M. Chen

    2013-03-01

    Full Text Available The development of models and the “Virtual Detector for Synchrotron Radiation” (vdsr code that accurately describe the production of synchrotron radiation are described. These models and code are valid in the classical and linear (single-scattering quantum regimes and are capable of describing radiation produced from laser-plasma accelerators (LPAs through a variety of mechanisms including betatron radiation, undulator radiation, and Thomson/Compton scattering. Previous models of classical synchrotron radiation, such as those typically used for undulator radiation, are inadequate in describing the radiation spectra from electrons undergoing small numbers of oscillations. This is due to an improper treatment of a mathematical evaluation at the end points of an integration that leads to an unphysical plateau in the radiation spectrum at high frequencies, the magnitude of which increases as the number of oscillation periods decreases. This is important for betatron radiation from LPAs, in which the betatron strength parameter is large but the number of betatron periods is small. The code vdsr allows the radiation to be calculated in this regime by full integration over each electron trajectory, including end-point effects, and this code is used to calculate betatron radiation for cases of experimental interest. Radiation from Thomson scattering and Compton scattering is also studied with vdsr. For Thomson scattering, radiation reaction is included by using the Sokolov method for the calculation of the electron dynamics. For Compton scattering, quantum recoil effects are considered in vdsr by using Monte Carlo methods. The quantum calculation has been benchmarked with the classical calculation in a classical regime.

  13. Tracking the density evolution in counter-propagating shock waves using imaging X-ray scattering

    Czech Academy of Sciences Publication Activity Database

    Zastrau, U.; Gamboa, E. J.; Kraus, D.; Benage, J. F.; Drake, R. P.; Efthimion, P.; Falk, Kateřina; Falcone, R.W.; Fletcher, L. B.; Galtier, E.; Gauthier, M.; Granados, E.; Hastings, J.B.; Heimann, P.; Hill, K.; Keiter, P. A.; Lu, J.; MacDonald, M. J.; Montgomery, D. S.; Nagler, B.; Pablant, N.; Schropp, A.; Tobias, B.; Gericke, D.O.; Glenzer, S. H.; Lee, H. J.

    2016-01-01

    Roč. 109, č. 3 (2016), 1-4, č. článku 031108. ISSN 0003-6951 R&D Projects: GA MŠk LQ1606; GA MŠk EF15_008/0000162 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : Thomson scattering * metal transition * compression * deuterium * diamond * carbon * matter Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.411, year: 2016

  14. Temperature measurements in ZT-40M

    International Nuclear Information System (INIS)

    Little, E.M.; Haberstich, A.; Thomas, K.S.; Watt, R.G.

    1983-01-01

    Electron temperatures derived from Thomson scattering and ultrasoft x-ray (USXR) measurements taken before and after machine modifications are compared for ZT-40M. Modifications were made to the magnetic field windings to reduce field errors and the joints in the aluminum shell were coated with joint compound to reduce resistance and make all joints electrically uniform. These modifications resulted in increased plasma lifetime in ZT-40M from less than 10 ms to over 20 ms. Thomson scattering measurements were made with a single-point Thomson scattering apparatus. The scattered spectrum is collected by a three-grating spectrometer. The soft x rays are collected by a two-foil differential transmission system whose foil ratios may be easily varied. Before modifications the Thomson scattering and soft x-ray temperatures agreed up until 3 to 4 ms into the discharge. After this time the Thomson scattering temperature decreased slowly while the soft x-ray ''temperature'' increased rapidly. field errors resulted in Thomson scattering and USXR ''temperature'' time histories remaining fairly flat out to 10 to 11 ms, but introduced a small discrepancy (about 50 eV) in the absolute value of the temperatures. This change may be due either to the change in foil thickness used or to changes in radial temperature profiles. Profile changes may have been caused by the addition of four poloidal limiters or improvements to the magnetic field topology. After modifications the temperatures from both Thomson scattering and USXR were lower and the plasma density was higher. This is probably a result of the lower plasma-wall interaction with the new configuration

  15. The Kelvin-Thomson atom

    International Nuclear Information System (INIS)

    Walton, A.J.

    1977-01-01

    The contributions made by Kelvin and later by J.J. Thomson to the 'current-bun' model of the atom are discussed. It is felt that the model is worth retaining as a didactic aid since it serves as a good example around which to hang a discussion of modelling as well as providing good examples of the application of Coulomb's and Gauss's laws. The structure of atoms containing up to six electrons is examined using an analysis based on this model. It is shown that it is possible to have a mechanically stable arrangement of up to six electrons located within a sphere of uniform positive charge. With up to three electrons the arrangement is coplanar with the centre of the sphere. (U.K.)

  16. J. J. Thomson and the Discovery of the Electron

    Science.gov (United States)

    Squires, Gordon

    1997-04-01

    Joseph John Thomson (1856-1940) was appointed to the Chair of Experimental Physics in the Cavendish Laboratory at the University of Cambridge at the age of 28 and started research on the conduction of electricity through gases at low pressure. He studied the properties of the rays emanating from the cathode in a gas discharge by deflecting them with electric and magnetic fields, and in 1897 announced that they were negatively charged particles about 2000 times lighter than hydrogen atoms, the lightest particles then known. Further, the mass of the particles was the same, irrespective of the nature of the gas in the discharge tube and the material of the cathode. He concluded that he had found a new particle, a universal constituent of matter. The discovery of the particle, subsequently called the electron, was one of the most significant events in the history of science. The talk will give a brief account of Thomson's career and the experiments leading to the discovery.

  17. Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

    Science.gov (United States)

    Piotrowska, A.; Chorowski, M.; Dorosz, P.

    2017-02-01

    Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

  18. Polarization of Coronal Forbidden Lines

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hao; Qu, Zhongquan [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Landi Degl’Innocenti, Egidio, E-mail: sayahoro@ynao.ac.cn [Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Largo E. Fermi 2, I-50125 Firenze (Italy)

    2017-03-20

    Since the magnetic field is responsible for most manifestations of solar activity, one of the most challenging problems in solar physics is the diagnostics of solar magnetic fields, particularly in the outer atmosphere. To this end, it is important to develop rigorous diagnostic tools to interpret polarimetric observations in suitable spectral lines. This paper is devoted to analyzing the diagnostic content of linear polarization imaging observations in coronal forbidden lines. Although this technique is restricted to off-limb observations, it represents a significant tool to diagnose the magnetic field structure in the solar corona, where the magnetic field is intrinsically weak and still poorly known. We adopt the quantum theory of polarized line formation developed in the framework of the density matrix formalism, and synthesize images of the emergent linear polarization signal in coronal forbidden lines using potential-field source-surface magnetic field models. The influence of electronic collisions, active regions, and Thomson scattering on the linear polarization of coronal forbidden lines is also examined. It is found that active regions and Thomson scattering are capable of conspicuously influencing the orientation of the linear polarization. These effects have to be carefully taken into account to increase the accuracy of the field diagnostics. We also found that linear polarization observation in suitable lines can give valuable information on the long-term evolution of the magnetic field in the solar corona.

  19. Rothmund-Thomson syndrome and tolerance of chemoradiotherapy

    International Nuclear Information System (INIS)

    Borg, M.F.; Olver, I.N.; Hill, M.P.

    1998-01-01

    Rothmund-Thomson syndrome (RTS) is a rare disorder with a predisposition for cutaneous and non-cutaneous malignancy. It is speculated that ultraviolet (UV) sensitivity and deficient DNA repair may account for this predisposition and influence the tolerance of chemoradiotherapeutic management. A case is reported of the management of an RTS patient with squamous cell carcinoma of the tongue who demonstrated increased radiosensitivity and tissue intolerance to chemotherapy. Copyright (1998) Blackwell Science Pty Ltd

  20. Numerical Modeling of the Thomson Ring in Stationary Levitation Using FEM-Electrical Network and Newton-Raphson

    Directory of Open Access Journals (Sweden)

    Guzmán Juan

    2015-07-01

    Full Text Available There are a lot of applications of the Thomson ring: levitation of superconductor materials, power interrupters (used as actuator and elimination of electric arcs. Therefore, it is important the numerical modeling of Thomson ring. The aim of this work is to model the stationary levitation of the Thomson ring. This Thomson ring consists of a copper coil with ferromagnetic core and an aluminum ring threaded in the core. The coil is fed by a cosine voltage to ensure that the aluminum ring is in a stationary levitated position. In this situation, the state of the electromagnetic field is stable and can be used the phasor equations of the electromagnetic field. These equations are discretized using the Galerkin method in the Lagrange base space (finite element method, FEM. These equations are solved using the COMSOL software. A methodology is also described (which uses the Newton-Raphson method that obtains the separation between coil and aluminum ring. The numerical solutions of this separation are compared with experimental data. The conclusion is that the magnetic coupling of the aluminum ring on the coil can be neglected if the source voltage is high.

  1. Conformation of cyclic and linear polydimethylsiloxane in the melt a small-angle neutron-scattering study

    CERN Document Server

    Gagliardi, S; Dagger, A; Semlyen, A J

    2002-01-01

    In this study we report small-angle neutron-scattering measurements of cyclic and linear polydimethylsiloxane (PDMS) in the melt. It has been suggested that due to the presence of topological constraints, rings in the melt may be more compact than Gaussian chains. We show that the cyclic chains are partially collapsed and do not follow Gaussian statistics: the weight-average radius of gyration R sub g sub , sub w is found to be proportional to M sub w sup 0 sup . sup 5 sup 3 and M sub w sup 0 sup . sup 4 sup 0 in the case of linear and cyclic PDMS, respectively. The results are in agreement with recent computer simulations, which predict R sub g to be proportional to N sup 2 sup / sup 5 , where N is the degree of polymerisation. (orig.)

  2. Probing strong field ionization of solids with a Thomson parabola ...

    Indian Academy of Sciences (India)

    2014-01-11

    Jan 11, 2014 ... that generate peak intensity up to 1022 W/cm2 on a table top [1]. ... and energy, plasma wake fields are generated that accelerate electrons to GeVs ... more detail, it is inevitable to use Thomson parabola spectrometer (TPS).

  3. Design of a 4.8-m ring for inverse Compton scattering x-ray source

    Directory of Open Access Journals (Sweden)

    H. S. Xu

    2014-07-01

    Full Text Available In this paper we present the design of a 50 MeV compact electron storage ring with 4.8-meter circumference for the Tsinghua Thomson scattering x-ray source. The ring consists of four dipole magnets with properly adjusted bending radii and edge angles for both horizontal and vertical focusing, and a pair of quadrupole magnets used to adjust the horizontal damping partition number. We find that the dynamic aperture of compact storage rings depends essentially on the intrinsic nonlinearity of the dipole magnets with small bending radius. Hamiltonian dynamics is found to agree well with results from numerical particle tracking. We develop a self-consistent method to estimate the equilibrium beam parameters in the presence of the intrabeam scattering, synchrotron radiation damping, quantum excitation, and residual gas scattering. We also optimize the rf parameters for achieving a maximum x-ray flux.

  4. Thomson scattering measuring device using high sensitivity photomultipliers: 16% up to 860nm

    International Nuclear Information System (INIS)

    Hesse, M.

    1976-03-01

    Photomultipliers with high quantum efficiency were used to observe the entire rubis laser light spectrum scattered by a plasma. The optical and electronic acquisition device used to study this spectrum is described. The spectra obtained revealed a dissymmetry larger than that expected from relativistic theory. These results could not be interpreted. The diagnostic sensitivity allows the measurement of low electron densities (2.10 12 ecm -3 ) [fr

  5. Vector boson scattering at CLIC

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, Wolfgang; Fleper, Christian [Department Physik, Universitaet Siegen, 57068 Siegen (Germany); Reuter, Juergen [DESY Theory Group, 22603 Hamburg (Germany); Sekulla, Marco [Institut fuer Theoretische Physik, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany)

    2016-07-01

    Linear colliders operating in a range of multiple TeV are able to investigate the details of vector boson scattering and electroweak symmetry breaking. We calculate cross sections with the Monte Carlo generator WHIZARD for vector boson scattering processes at the future linear e{sup +} e{sup -} collider CLIC. By finding suitable cuts, the vector boson scattering signal processes are isolated from the background. Finally, we are able to determine exclusion sensitivities on the non-Standard Model parameters of the relevant dimension eight operators.

  6. The Gibbs-Thomson equation for a spherical coherent precipitate with applications to nucleation

    International Nuclear Information System (INIS)

    Rottman, C.; Voorhees, P.W.; Johnson, W.C.

    1988-01-01

    The conditions for interfacial thermodynamic equilibrium form the basis for the derivation of a number of basic equations in materials science, including the various forms of the Gibbs-Thomson equation. The equilibrium conditions pertaining to a curved interface in a two-phase fluid system are well-known. In contrast, the conditions for thermodynamic equilibrium at a curved interface in nonhydrostatically stressed solids have only recently been examined. These conditions can be much different from those at a fluid interface and, as a result, the Gibbs-Thomson equation appropriate to coherent solids is likely to be considerably different from that for fluids. In this paper, the authors first derive the conditions necessary for thermodynamic equilibrium at the precipitate-matrix interface of a coherent spherical precipitate. The authors' derivation of these equilibrium conditions includes a correction to the equilibrium conditions of Johnson and Alexander for a spherical precipitate in an isotropic matrix. They then use these conditions to derive the dependence of the interfacial precipitate and matrix concentrations on precipitate radius (Gibbs-Thomson equation) for a such a precipitate. In addition, these relationships are then used to calculate the critical radius for the nucleation of a coherent misfitting precipitate

  7. A high-order perturbation of surfaces method for scattering of linear waves by periodic multiply layered gratings in two and three dimensions

    Science.gov (United States)

    Hong, Youngjoon; Nicholls, David P.

    2017-09-01

    The capability to rapidly and robustly simulate the scattering of linear waves by periodic, multiply layered media in two and three dimensions is crucial in many engineering applications. In this regard, we present a High-Order Perturbation of Surfaces method for linear wave scattering in a multiply layered periodic medium to find an accurate numerical solution of the governing Helmholtz equations. For this we truncate the bi-infinite computational domain to a finite one with artificial boundaries, above and below the structure, and enforce transparent boundary conditions there via Dirichlet-Neumann Operators. This is followed by a Transformed Field Expansion resulting in a Fourier collocation, Legendre-Galerkin, Taylor series method for solving the problem in a transformed set of coordinates. Assorted numerical simulations display the spectral convergence of the proposed algorithm.

  8. Linear versus non-linear structural information limit in high-resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Van Aert, S.; Chen, J.H.; Van Dyck, D.

    2010-01-01

    A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has

  9. J J Thomson and the discovery of the electron

    International Nuclear Information System (INIS)

    Squires, Gordon

    1997-01-01

    This short biography describes the life of J.J. Thomson, head of the Cavendish Laboratory in Cambridge. His early life as well as his contributions to physics, including the discovery of the electron from his research on cathode rays in 1897 are included. The work of other contributors to the understanding of electron properties is also noted briefly. (UK)

  10. Induced Compton-scattering effects in radiation-transport approximations

    International Nuclear Information System (INIS)

    Gibson, D.R. Jr.

    1982-02-01

    The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions

  11. Thomson parabola spectrometry for gold laser generated plasmas

    Czech Academy of Sciences Publication Activity Database

    Torrisi, L.; Cutroneo, M.; Andó, L.; Ullschmied, Jiří

    2013-01-01

    Roč. 20, č. 2 (2013), 023106-023106 ISSN 1070-664X R&D Projects: GA MŠk LM2010014 Institutional research plan: CEZ:AV0Z20430508 Keywords : acceleration * ions * Thomson parabola spectrometry * PALS laser * laser targets * gold ions Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.249, year: 2013 http://pop.aip.org/resource/1/phpaen/v20/i2/p023106_s1

  12. A linear evolution for non-linear dynamics and correlations in realistic nuclei

    International Nuclear Information System (INIS)

    Levin, E.; Lublinsky, M.

    2004-01-01

    A new approach to high energy evolution based on a linear equation for QCD generating functional is developed. This approach opens a possibility for systematic study of correlations inside targets, and, in particular, inside realistic nuclei. Our results are presented as three new equations. The first one is a linear equation for QCD generating functional (and for scattering amplitude) that sums the 'fan' diagrams. For the amplitude this equation is equivalent to the non-linear Balitsky-Kovchegov equation. The second equation is a generalization of the Balitsky-Kovchegov non-linear equation to interactions with realistic nuclei. It includes a new correlation parameter which incorporates, in a model-dependent way, correlations inside the nuclei. The third equation is a non-linear equation for QCD generating functional (and for scattering amplitude) that in addition to the 'fan' diagrams sums the Glauber-Mueller multiple rescatterings

  13. Delayed Union of a Jones Fracture in a Patient With Rothmund-Thomson Syndrome: A Case Report and Review of the Literature.

    Science.gov (United States)

    Barisonek, Kirsten L; Protzman, Nicole M; Wobst, Garrett M; Brigido, Stephen A

    2016-01-01

    Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis, characterized by poikiloderma, small stature, juvenile cataracts, sparse hair, skeletal abnormalities, and a predisposition to osteogenic sarcomas and skin cancers. Although numerous skeletal abnormalities have been described in patients with Rothmund-Thomson syndrome, to our knowledge, only 1 study has shown evidence of delayed fracture healing in a patient with Rothmund-Thomson syndrome. We present the case of a 13-year-old female diagnosed with Rothmund-Thomson syndrome who demonstrated delayed union of her fifth metatarsal after a Jones fracture. She was treated conservatively for 6 weeks with non-weightbearing cast immobilization and was then transitioned to a controlled ankle motion walker for an additional 4 weeks. Two months later, however, she continued to experience pain, and, on radiographic examination, the fracture remained unchanged. Therefore, with her guardian's consent, the patient elected to undergo open reduction and internal fixation of the fifth metatarsal fracture. At 8 weeks postoperatively, the patient reported a subsidence of symptoms and had returned to normal activity. With our report, we hope to increase practitioner awareness that delayed bone healing could be a possibility in patients with Rothmund-Thomson syndrome and encourage consideration of routine imaging and supplementation with calcium and vitamin D. Additionally, the present findings suggest that patients with Rothmund-Thomson syndrome could benefit from early surgical intervention, given their poor bone healing capacity and high likelihood of nonunion. Although the association between impaired bone healing and Rothmund-Thomson syndrome is rational, additional studies are needed to determine the prevalence of chronic nonunion in this patient population. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Bibliometric Rankings of Journals Based on the Thomson Reuters Citations Database

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); M.J. McAleer (Michael)

    2015-01-01

    markdownabstract__Abstract__ Virtually all rankings of journals are based on citations, including self citations by journals and individual academics. The gold standard for bibliometric rankings based on citations data is the widely-used Thomson Reuters Web of Science (2014) citations database,

  15. Bibliometric Rankings of Journals based on the Thomson Reuters Citations Database

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); M.J. McAleer (Michael)

    2015-01-01

    markdownabstract__Abstract__ Virtually all rankings of journals are based on citations, including self citations by journals and individual academics. The gold standard for bibliometric rankings based on citations data is the widely-used Thomson Reuters Web of Science (2014) citations database,

  16. Laser light scattering in a laser-induced argon plasma: Investigations of the shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Pokrzywka, B. [Obserwatorium Astronomiczne na Suhorze, Uniwersytet Pedagogiczny, ulica Podchorazych 2, 30-084 Krakow (Poland); Mendys, A., E-mail: agata.mendys@uj.edu.pl [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Dzierzega, K.; Grabiec, M. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Pellerin, S. [GREMI, site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France)

    2012-08-15

    Shock wave produced by a laser induced spark in argon at atmospheric pressure was examined using Rayleigh and Thomson scattering. The spark was generated by focusing a laser pulse from the second harmonic ({lambda} = 532 nm) of a nanosecond Nd:YAG laser using an 80 mm focal length lens, with a fluence of 2 kJ{center_dot}cm{sup -2}. Images of the spark emission were recorded for times between 30 ns and 100 {mu}s after the laser pulse in order to characterize its spatial evolution. The position of the shock wave at several instants of its evolution and for several plasma regions was determined from the Rayleigh-scattered light of another nanosecond Nd:YAG laser (532 nm, 40 J{center_dot}cm{sup -2} fluence). Simultaneously, Thomson scattering technique was applied to determine the electron density and temperature in the hot plasma core. Attempts were made to describe the temporal evolution of the shock wave within a self-similar model, both by the simple Sedov-Taylor formula as well as its extension deduced by de Izarra. The temporal radial evolution of the shock position is similar to that obtained within theory taking into account the counter pressure of the ambient gas. Density profiles just behind the shock front are in qualitative agreement with those obtained by numerically solving the Euler equations for instantaneous explosion at a point with counter pressure. - Highlights: Black-Right-Pointing-Pointer We investigated shock wave evolution by Rayleigh scattering method. Black-Right-Pointing-Pointer 2D map of shockwave position for several times after plasma generation is presented. Black-Right-Pointing-Pointer Shock wave evolution is not satisfactorily described within self-similar models. Black-Right-Pointing-Pointer Evolution of shock position similar to theory taking into account counter pressure. Black-Right-Pointing-Pointer Density profile behind the shock similar to numerical solution of Euler equations.

  17. Induced Compton scattering effects in radiation transport approximations

    International Nuclear Information System (INIS)

    Gibson, D.R. Jr.

    1982-01-01

    In this thesis the method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions

  18. Verification of the Thomson-Onsager reciprocity relation for spin caloritronics

    NARCIS (Netherlands)

    Dejene, F. K.; Flipse, J.; van Wees, B. J.

    2014-01-01

    We investigate the Thomson-Onsager relation between the spin-dependent Seebeck and spin-dependent Peltier effect. To maintain identical device and measurement conditions we measure both effects in a single Ni80Fe20/Cu/Ni80Fe20 nanopillar spin valve device subjected to either an electrical or a

  19. Flash of the Cathode Rays: A History of J J Thomson's Electron

    International Nuclear Information System (INIS)

    Rechenberg, Helmut

    1997-01-01

    The author, a senior physicist from Berkeley having some experience in historical accounts, covers well the standard story of J J Thomson's discovery of the electron, one hundred years ago. Starting from the investigations of cathode rays in Germany, France and mainly England, the successful path of J J is covered in some detail using available information (letters, notebooks, diaries, publications), as well as his later work on positive rays and the atomic model. Lesser emphasis is given to the parallel developments connected with the Zeeman effect. However, a synopsis of the story of β-rays, the measurement of the elementary charge and the rise of the Rutherford - Bohr nuclear model of the atom is included. Dahl presents the physical contents from the standard literature in a clear and convincing way. He illustrates the narrative with (well-chosen and well-reproduced) portraits of the people involved and sketches of their original apparatus. Hence the book can be recommended highly to physicists, who will be reminded of one of the most important events in the earlier history of their field. A broader public, including other scientists, and perhaps attentive high school graduates, might also benefit from the book, not to mention professional science historians (who may appreciate the detailed, reliable description of subtle experiments and their tricky interpretation). The author succeeds far less well in providing the general background (in the history of physics and beyond) of the Thomson story. The electron as a fundamental concept existed and was applied long before J Pluecker's discovery of cathodes rays (for example, by A-M Ampere and his successors), and the importance of the work by W Weber, F Neumann and R Clausius (to mention just a few scientists in the 19th century) is mainly suppressed. Dahl's treatment of P Lenard's work around 1900, for which Lenard won the Nobel prize before Thomson, is quite unfair. Further, Chapter 14 on the French N-rays and

  20. Thomson scattering of chiral tensors and scalars against a self-dual string

    International Nuclear Information System (INIS)

    Arvidsson, Paer; Flink, Erik; Henningson, Maans

    2002-01-01

    We give a non-technical outline of a program to study the (2,0) theories in six space-time dimensions. Away from the origin of their moduli space, these theories describe the interactions of tensor multiplets and self-dual spinning strings. We argue that if the ratio between the square of the energy of a process and the string tension is taken to be small, it should be possible to study the dynamics of such a system perturbatively in this parameter. As a first step in this direction, we perform a classical computation of the amplitude for scattering chiral tensor and scalar fields (i.e. the bosonic part of a tensor multiplet) against a self-dual spinnless string. (author)

  1. Laser-aided plasma diagnostics

    NARCIS (Netherlands)

    Donne, A. J. H.; Barth, C. J.

    2008-01-01

    This paper will focus on two types of laser-aided diagnostics: Thomson scattering and laser-induced fluorescence. Thomson scattering is a very powerful diagnostic, which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can

  2. Generalized model screening potentials for Fermi-Dirac plasmas

    Science.gov (United States)

    Akbari-Moghanjoughi, M.

    2016-04-01

    In this paper, some properties of relativistically degenerate quantum plasmas, such as static ion screening, structure factor, and Thomson scattering cross-section, are studied in the framework of linearized quantum hydrodynamic theory with the newly proposed kinetic γ-correction to Bohm term in low frequency limit. It is found that the correction has a significant effect on the properties of quantum plasmas in all density regimes, ranging from solid-density up to that of white dwarf stars. It is also found that Shukla-Eliasson attractive force exists up to a few times the density of metals, and the ionic correlations are seemingly apparent in the radial distribution function signature. Simplified statically screened attractive and repulsive potentials are presented for zero-temperature Fermi-Dirac plasmas, valid for a wide range of quantum plasma number-density and atomic number values. Moreover, it is observed that crystallization of white dwarfs beyond a critical core number-density persists with this new kinetic correction, but it is shifted to a much higher number-density value of n0 ≃ 1.94 × 1037 cm-3 (1.77 × 1010 gr cm-3), which is nearly four orders of magnitude less than the nuclear density. It is found that the maximal Thomson scattering with the γ-corrected structure factor is a remarkable property of white dwarf stars. However, with the new γ-correction, the maximal scattering shifts to the spectrum region between hard X-ray and low-energy gamma-rays. White dwarfs composed of higher atomic-number ions are observed to maximally Thomson-scatter at slightly higher wavelengths, i.e., they maximally scatter slightly low-energy photons in the presence of correction.

  3. A micromachined Joule–Thomson cryogenic cooler with parallel two-stage expansion

    NARCIS (Netherlands)

    Cao, Haishan; Vanapalli, Srinivas; Holland, Herman J.; Vermeer, Cristian Hendrik; ter Brake, Hermanus J.M.

    2016-01-01

    There is an increasing need for localized cooling in integrated circuit/microfluidic chips, where cooling is currently achieved by relatively large and bulky cooling systems. Joule–Thomson (JT) cryocoolers are suitable to address these size limitations because they have no cold moving parts and,

  4. Relativistic theory of particles in a scattering flow III: photon transport.

    Science.gov (United States)

    Achterberg, A.; Norman, C. A.

    2018-06-01

    We use the theory developed in Achterberg & Norman (2018a) and Achterberg & Norman (2018b) to calculate the stress due to photons that are scattered elastically by a relativistic flow. We show that the energy-momentum tensor of the radiation takes the form proposed by Eckart (1940). In particular we show that no terms associated with a bulk viscosity appear if one makes the diffusion approximation for radiation transport and treats the radiation as a separate fluid. We find only shear (dynamic) viscosity terms and heat flow terms in our expression for the energy-momentum tensor. This conclusion holds quite generally for different forms of scattering: Krook-type integral scattering, diffusive (Fokker-Planck) scattering and Thomson scattering. We also derive the transport equation in the diffusion approximation that shows the effects of the flow on the photon gas in the form of a combination of adiabatic heating and an irreversible heating term. We find no diffusive changes to the comoving number density and energy density of the scattered photons, in contrast with some published results in Radiation Hydrodynamics. It is demonstrated that these diffusive corrections to the number- and energy density of the photons are in fact higher-order terms that can (and should) be neglected in the diffusion approximation. Our approach eliminates these terms at the root of the expansion that yields the anisotropic terms in the phase-space density of particles and photons, the terms responsible for the photon viscosity.

  5. Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

    International Nuclear Information System (INIS)

    Papell, S.S.; Nyland, T.W.; Saiyed, N.H.

    1992-07-01

    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. 3 refs

  6. Introduction to neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.

  7. How fast can a black hole eat. [Equation stationary spherically symmetric solutions, Thompson scattering, mass flow

    Energy Technology Data Exchange (ETDEWEB)

    Kafka, P; Meszaros, P [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (Germany, F.R.)

    1976-11-01

    Stationary spherically symmetric solutions of the equations for accretion of large mass flows onto a black hole, including the interaction of matter and radiation due to Thomson scattering in diffusion approximation are constructed. The relevance of these solutions is discussed with respect to the question of whether the limitation of the luminosity (Eddington limit) also implies an upper bound to the possible rate of mass flow. The question remains open until all instabilities have been studied. At the moment a negative answer is favoured.

  8. Suppression of Stimulated Brillouin Scattering in multiple-ion species inertial confinement fusion Hohlraum Plasmas

    International Nuclear Information System (INIS)

    Neumayer, P

    2007-01-01

    A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO 2 and C 3 H 8 varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ of 351-nm light, thus increasing progressively Landau damping by an order of magnitude at constant electron density and temperature. A delayed 351-nm interaction beam, spatially smoothed to produce a 200-(micro)m laser spot at best focus, has propagated along the axis of the hohlraum. The backscattered light, both into the lens and outside, the transmitted light through the hohlraum plasma and the radiation temperature of the hohlraum has been measured. For ignition relevant laser intensities (3-9 10 14 Wcm -2 ), we find that the SBS reflectivity scales as predicted with Landau damping from >30% to <1%. Simultaneously, the hohlraum radiation

  9. Generalized two-dimensional (2D) linear system analysis metrics (GMTF, GDQE) for digital radiography systems including the effect of focal spot, magnification, scatter, and detector characteristics.

    Science.gov (United States)

    Jain, Amit; Kuhls-Gilcrist, Andrew T; Gupta, Sandesh K; Bednarek, Daniel R; Rudin, Stephen

    2010-03-01

    The MTF, NNPS, and DQE are standard linear system metrics used to characterize intrinsic detector performance. To evaluate total system performance for actual clinical conditions, generalized linear system metrics (GMTF, GNNPS and GDQE) that include the effect of the focal spot distribution, scattered radiation, and geometric unsharpness are more meaningful and appropriate. In this study, a two-dimensional (2D) generalized linear system analysis was carried out for a standard flat panel detector (FPD) (194-micron pixel pitch and 600-micron thick CsI) and a newly-developed, high-resolution, micro-angiographic fluoroscope (MAF) (35-micron pixel pitch and 300-micron thick CsI). Realistic clinical parameters and x-ray spectra were used. The 2D detector MTFs were calculated using the new Noise Response method and slanted edge method and 2D focal spot distribution measurements were done using a pin-hole assembly. The scatter fraction, generated for a uniform head equivalent phantom, was measured and the scatter MTF was simulated with a theoretical model. Different magnifications and scatter fractions were used to estimate the 2D GMTF, GNNPS and GDQE for both detectors. Results show spatial non-isotropy for the 2D generalized metrics which provide a quantitative description of the performance of the complete imaging system for both detectors. This generalized analysis demonstrated that the MAF and FPD have similar capabilities at lower spatial frequencies, but that the MAF has superior performance over the FPD at higher frequencies even when considering focal spot blurring and scatter. This 2D generalized performance analysis is a valuable tool to evaluate total system capabilities and to enable optimized design for specific imaging tasks.

  10. Joule-Thomson expansion of the charged AdS black holes

    International Nuclear Information System (INIS)

    Oekcue, Oezguer; Aydiner, Ekrem

    2017-01-01

    In this paper, we study Joule-Thomson effects for charged AdS black holes. We obtain inversion temperatures and curves. We investigate similarities and differences between van der Waals fluids and charged AdS black holes for the expansion. We obtain isenthalpic curves for both systems in the T-P plane and determine the cooling-heating regions. (orig.)

  11. Joule-Thomson expansion of the charged AdS black holes

    Energy Technology Data Exchange (ETDEWEB)

    Oekcue, Oezguer; Aydiner, Ekrem [Istanbul University, Department of Physics, Faculty of Science, Vezneciler, Istanbul (Turkey)

    2017-01-15

    In this paper, we study Joule-Thomson effects for charged AdS black holes. We obtain inversion temperatures and curves. We investigate similarities and differences between van der Waals fluids and charged AdS black holes for the expansion. We obtain isenthalpic curves for both systems in the T-P plane and determine the cooling-heating regions. (orig.)

  12. The influence of Thomson effect in the energy and exergy efficiency of an annular thermoelectric generator

    International Nuclear Information System (INIS)

    Kaushik, S.C.; Manikandan, S.

    2015-01-01

    Highlights: • Exergy analysis in the annular thermoelectric generator (ATEG) system is proposed. • Analytical expressions for the power output, exergy efficiency of an ATEG is derived. • The effects of S r , R L , and θ in P out and exergy efficiency of an ATEG is studied. • The influence of Thomson effect in P out and exergy efficiency of an ATEG is studied. - Abstract: The exoreversible thermodynamic model of an annular thermoelectric generator (ATEG) considering Thomson effect in conjunction with Peltier, Joule and Fourier heat conduction has been investigated using exergy analysis. New expressions for optimum current at the maximum power output and maximum energy, exergy efficiency conditions, and dimensionless irreversibilities in the ATEG are derived. The modified expression for figure of merit of a thermoelectric generator considering the Thomson effect has also been obtained. The results show that the power output, energy and exergy efficiency of the ATEG is lower than the flat plate thermoelectric generator. The effects of annular shape parameter (S r = r 2 /r 1 ), load resistance (R L ), dimensionless temperature ratio (θ = T h /T c ) and the thermal and electrical contact resistances in power output, energy/exergy efficiency of the ATEG have been studied. It has also been proved that because of the influence of Thomson effect, the power output and energy/exergy efficiency of the ATEG is reduced. This study will help in the designing of the actual annular thermoelectric generation systems

  13. Neutron angular distribution in (γ, n reactions with linearly polarized γ-ray beam generated by laser Compton scattering

    Directory of Open Access Journals (Sweden)

    K. Horikawa

    2014-10-01

    Full Text Available In 1957, Agodi predicted that the neutron angular distribution in (γ, n reactions with a 100% linearly polarized γ-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a+b⋅cos⁡(2ϕ at the polar angle θ=90°, where ϕ is the azimuthal angle. However, this prediction has not been experimentally confirmed in over half a century. We have verified experimentally this angular distribution in the (γ, n reaction for 197Au, 127I, and natural Cu targets using linearly polarized laser Compton scattering γ-rays. The result suggests that the (γ→, n reaction is a novel tool to study nuclear physics in the giant dipole resonance region.

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

    DEFF Research Database (Denmark)

    Meo, Fernando; Bindslev, Henrik; Korsholm, Søren Bang

    2008-01-01

    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. ©2008 American Institute of Physics...

  15. Sensitivity of Micromachined Joule-Thomson Cooler to Clogging Due to Moisture

    NARCIS (Netherlands)

    Cao, Haishan; Vanapalli, Srinivas; Holland, Herman J.; Vermeer, Cristian Hendrik; ter Brake, Hermanus J.M.

    2015-01-01

    A major issue in long-term operation of micromachined Joule-Thomson coolers is the clogging of the microchannels and/or the restriction due to the deposition of water molecules present in the working fluid. In this study, we present the performance of a microcooler operated with nitrogen gas with

  16. Do Cloaked Objects Really Scatter Less?

    Directory of Open Access Journals (Sweden)

    Francesco Monticone

    2013-10-01

    Full Text Available We discuss the global scattering response of invisibility cloaks over the entire electromagnetic spectrum, from static to very high frequencies. Based on linearity, causality, and energy conservation, we show that the total extinction and scattering, integrated over all wavelengths, of any linear, passive, causal, and nondiamagnetic cloak, necessarily increase compared to the uncloaked case. In light of this general principle, we provide a quantitative measure to compare the global performance of different cloaking techniques and we discuss solutions to minimize the global scattering signature of an object using thin, superconducting shells. Our results provide important physical insights on how invisibility cloaks operate and affect the global scattering of an object, suggesting ways to defeat countermeasures aimed at detecting cloaked objects using short impinging pulses.

  17. Study of flow and loss processes at the ends of a linear theta pinch. Progress report for the period June 1, 1976--May 31, 1977

    International Nuclear Information System (INIS)

    York, T.M.; Klevans, E.H.

    1977-02-01

    Experimental and analytical studies initiating and supporting research on flow and energy losses at the ends of a linear theta pinch have been carried out. A 25 cm linear pinch coil has been driven by a 515,000 A discharge with 10 μsec half-cycle time supplied by a 100 μF, 18 kV energy storage system. With reliable preionization generated up to 400 mT He, current sheath behavior has been identified with magnetic loop probes and double loop probes. Spectroscopic determination of preionization has been made. A ruby laser Thomson scattering diagnostic has been designed and is being procured. A study of transient plasma behavior in a 10 cm theta pinch has been carried out with a Twyman-Green interferometer using a 7 mW He--Ne CW laser. Pressure, electric field, and velocity probe diagnostics have received preliminary testing. Design work has been completed for the doubling of pinch length and energy storage system. Studies of particle loss scaling and reactor scaling of linear theta pinch devices have been reported. Detailed calculations of plasma properties at the end of the pinch coil following expansion from the central coil have been carried out. A O--D, time dependent computer code that includes conduction, convection, and magnetic field diffusion has been developed. Predicted plasma behavior is in good agreement with experimental data

  18. New conformations of linear polyubiquitin chains from crystallographic and solution-scattering studies expand the conformational space of polyubiquitin.

    Science.gov (United States)

    Thach, Trung Thanh; Shin, Donghyuk; Han, Seungsu; Lee, Sangho

    2016-04-01

    The conformational flexibility of linkage-specific polyubiquitin chains enables ubiquitylated proteins and their receptors to be involved in a variety of cellular processes. Linear or Met1-linked polyubiquitin chains, associated with nondegradational cellular signalling pathways, have been known to adopt multiple conformations from compact to extended conformations. However, the extent of such conformational flexibility remains open. Here, the crystal structure of linear Ub2 was determined in a more compact conformation than that of the previously known structure (PDB entry 3axc). The two structures differ significantly from each other, as shown by an r.m.s.d. between C(α) atoms of 3.1 Å. The compactness of the linear Ub2 structure in comparison with PDB entry 3axc is supported by smaller values of the radius of gyration (Rg; 18 versus 18.9 Å) and the maximum interatomic distance (Dmax; 55.5 versus 57.8 Å). Extra intramolecular hydrogen bonds formed among polar residues between the distal and proximal ubiquitin moieties seem to contribute to stabilization of the compact conformation of linear Ub2. An ensemble of three semi-extended and extended conformations of linear Ub2 was also observed by small-angle X-ray scattering (SAXS) analysis in solution. In addition, the conformational heterogeneity in linear polyubiquitin chains is clearly manifested by SAXS analyses of linear Ub3 and Ub4: at least three distinct solution conformations are observed in each chain, with the linear Ub3 conformations being compact. The results expand the extent of conformational space of linear polyubiquitin chains and suggest that changes in the conformational ensemble may be pivotal in mediating multiple signalling pathways.

  19. Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301.

    Science.gov (United States)

    Mathur; Green; Arav; Brotherton; Crenshaw; deKool; Elvis; Goodrich; Hamann; Hines; Kashyap; Korista; Peterson; Shields; Shlosman; van Breugel W; Voit

    2000-04-20

    We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (NH greater, similar1024 cm-2) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible.

  20. Synthetic acceleration methods for linear transport problems with highly anisotropic scattering

    International Nuclear Information System (INIS)

    Khattab, K.M.; Larsen, E.W.

    1992-01-01

    The diffusion synthetic acceleration (DSA) algorithm effectively accelerates the iterative solution of transport problems with isotropic or mildly anisotropic scattering. However, DSA loses its effectiveness for transport problems that have strongly anisotropic scattering. Two generalizations of DSA are proposed, which, for highly anisotropic scattering problems, converge at least an order of magnitude (clock time) faster than the DSA method. These two methods are developed, the results of Fourier analysis that theoretically predict their efficiency are described, and numerical results that verify the theoretical predictions are presented. (author). 10 refs., 7 figs., 5 tabs

  1. Synthetic acceleration methods for linear transport problems with highly anisotropic scattering

    International Nuclear Information System (INIS)

    Khattab, K.M.; Larsen, E.W.

    1991-01-01

    This paper reports on the diffusion synthetic acceleration (DSA) algorithm that effectively accelerates the iterative solution of transport problems with isotropic or mildly anisotropic scattering. However, DSA loses its effectiveness for transport problems that have strongly anisotropic scattering. Two generalizations of DSA are proposed, which, for highly anisotropic scattering problems, converge at least an order of magnitude (clock time) faster than the DSA method. These two methods are developed, the results of Fourier analyses that theoretically predict their efficiency are described, and numerical results that verify the theoretical predictions are presented

  2. Generalized model screening potentials for Fermi-Dirac plasmas

    International Nuclear Information System (INIS)

    Akbari-Moghanjoughi, M.

    2016-01-01

    In this paper, some properties of relativistically degenerate quantum plasmas, such as static ion screening, structure factor, and Thomson scattering cross-section, are studied in the framework of linearized quantum hydrodynamic theory with the newly proposed kinetic γ-correction to Bohm term in low frequency limit. It is found that the correction has a significant effect on the properties of quantum plasmas in all density regimes, ranging from solid-density up to that of white dwarf stars. It is also found that Shukla-Eliasson attractive force exists up to a few times the density of metals, and the ionic correlations are seemingly apparent in the radial distribution function signature. Simplified statically screened attractive and repulsive potentials are presented for zero-temperature Fermi-Dirac plasmas, valid for a wide range of quantum plasma number-density and atomic number values. Moreover, it is observed that crystallization of white dwarfs beyond a critical core number-density persists with this new kinetic correction, but it is shifted to a much higher number-density value of n_0 ≃ 1.94 × 10"3"7 cm"−"3 (1.77 × 10"1"0 gr cm"−"3), which is nearly four orders of magnitude less than the nuclear density. It is found that the maximal Thomson scattering with the γ-corrected structure factor is a remarkable property of white dwarf stars. However, with the new γ-correction, the maximal scattering shifts to the spectrum region between hard X-ray and low-energy gamma-rays. White dwarfs composed of higher atomic-number ions are observed to maximally Thomson-scatter at slightly higher wavelengths, i.e., they maximally scatter slightly low-energy photons in the presence of correction.

  3. Generalized model screening potentials for Fermi-Dirac plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Akbari-Moghanjoughi, M. [Faculty of Sciences, Department of Physics, Azarbaijan Shahid Madani University, 51745-406 Tabriz, Iran and International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum (Germany)

    2016-04-15

    In this paper, some properties of relativistically degenerate quantum plasmas, such as static ion screening, structure factor, and Thomson scattering cross-section, are studied in the framework of linearized quantum hydrodynamic theory with the newly proposed kinetic γ-correction to Bohm term in low frequency limit. It is found that the correction has a significant effect on the properties of quantum plasmas in all density regimes, ranging from solid-density up to that of white dwarf stars. It is also found that Shukla-Eliasson attractive force exists up to a few times the density of metals, and the ionic correlations are seemingly apparent in the radial distribution function signature. Simplified statically screened attractive and repulsive potentials are presented for zero-temperature Fermi-Dirac plasmas, valid for a wide range of quantum plasma number-density and atomic number values. Moreover, it is observed that crystallization of white dwarfs beyond a critical core number-density persists with this new kinetic correction, but it is shifted to a much higher number-density value of n{sub 0} ≃ 1.94 × 10{sup 37} cm{sup −3} (1.77 × 10{sup 10} gr cm{sup −3}), which is nearly four orders of magnitude less than the nuclear density. It is found that the maximal Thomson scattering with the γ-corrected structure factor is a remarkable property of white dwarf stars. However, with the new γ-correction, the maximal scattering shifts to the spectrum region between hard X-ray and low-energy gamma-rays. White dwarfs composed of higher atomic-number ions are observed to maximally Thomson-scatter at slightly higher wavelengths, i.e., they maximally scatter slightly low-energy photons in the presence of correction.

  4. Four new species of Nyctonympha Thomson, 1868 (Coleoptera, Cerambycidae, Lamiinae

    Directory of Open Access Journals (Sweden)

    Antonio Santos-Silva

    2017-06-01

    Full Text Available Four new species of Nyctonympha Thomson, 1868 are described: N. antonkozlovi sp. nov. and N. sinjaevi sp. nov. from Colombia, N. birai sp. nov. from Venezuela and N. mariahelenae sp. nov. from Brazil (Rondônia, Bolivia and Peru. Nyctonympha flavipes Aurivillius, 1990 is formally excluded from the Peruvian and Brazilian fauna. A provisional key to species of Nyctonympha is provided.

  5. High-energy resolution Thomson Parabola spectrometer for laser plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G. A. P.; Schillaci, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Carpinelli, M. [INFN Sezione di Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy); Cuttone, G.; Romano, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Maggiore, M. [Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague, Czech Republic and Laboratori Nazionali di Legnaro, INFN, Via Università 2, Legnaro (PD) (Italy); Ter-Avetisyan, S. [Laboratori Nazionali di Legnaro, INFN, Via Università 2, Legnaro (PD) (Italy); Tramontana, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and School of Mathematics and Physics, The Queen' s University Belfast, BT7 1NN (United Kingdom); Velyhan, A. [Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic)

    2013-07-26

    Thomson Parabola (TP) spectrometers are widely used devices for laser-driven beam diagnostics as they provide a complete set of information on the accelerated particles. A novel TP has been developed at LNS with a design able to detect protons up to 20 MeV. The layout design and some results obtained during the experimental campaign at PALS laboratory will be reported in the following.

  6. Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1979-September 30, 1980

    International Nuclear Information System (INIS)

    York, T.M.; Klevans, E.H.

    1980-05-01

    Experimental and analytical studies of particle and energy loss at the ends of a linear theta pinch have been carried out. A study of transients occurring in the formation of reversed trapped fields within the coil, and of transients in the end region of a 25 cm long device was completed. A 1-D code has proven to be highly accurate in describing loss events and defining transport mechanisms in different experiments and is described here. A study of loss along field lines in a 50 cm long device has generated new information on loss velocity, axial and radial temperature gradients, and has established an initial effort in understanding thermal loss to the walls. Rotation and parallel trapped fields have been added to the existing 0-D code. A new technique crowbar switch and magnetic field prediction code have been developed. Direct measurment of electron velocity with Thomson scattering was accomplished experimentally. A Nd-glass laser system, frequency doubled, is being developed for low density diagnostics. Theoretical results that accurately predict confinement in FRX devices are described

  7. Quasimonochromatic x-rays generated from nonlinear Thomson backscattering

    International Nuclear Information System (INIS)

    Lan Pengfei; Lu Peixiang; Cao Wei; Wang Xinlin

    2007-01-01

    The nonlinear Thomson backscattering in a circularly polarized Gaussian laser pulse is investigated and spectral characteristics of the emission are discussed. It is indicated that the frequency of the emitted light is up-shifted by the nonlinear doppler effect. By using a properly focused laser beam or putting the electron before the focus, the variety of the nonlinear Doppler shift during the interaction can be minimized and quasimonochromatic x-rays are generated. Taking into account the emission power, the optimum situations for generating quasimonochromatic x-rays are explored

  8. A hybrid Scatter/Transform cloaking model

    Directory of Open Access Journals (Sweden)

    Gad Licht

    2015-01-01

    Full Text Available A new Scatter/Transform cloak is developed that combines the light bending of refraction characteristic of a Transform cloak with the scatter cancellation characteristic of a Scatter cloak. The hybrid cloak incorporates both Transform’s variable index of refraction with modified linear intrusions to maximize the Scatter cloak effect. Scatter/Transform improved the scattering cross-section of cloaking in a 2-dimensional space to 51.7% compared to only 39.6% or 45.1% respectively with either Scatter or Transform alone. Metamaterials developed with characteristics based on the new ST hybrid cloak will exhibit superior cloaking capabilities.

  9. Survey Talk--New Laser and Optical Radiation Diagnostics

    International Nuclear Information System (INIS)

    Leemans, W.P.

    1998-01-01

    New techniques am reported for electron beam monitoring, that rely either on the analysis of the properties of wiggler radiation (from static magnetic fields as well as from laser ''undulators'', also referred to as Thomson scattering) or on the non-linear mixing of laser radiation with electron beam radiation. The different techniques reviewed are capable of providing information on femtosecond time scales and micron or even sub-micron spatial scales. The laser undulator is also proposed as a useful tool for non- destructive measurement of high power electron beams. An example is given of measuring electron beam energy and energy spread through spectral filtering of spontaneous wiggler radiation [1]. A novel technique based on fluctuational characteristics of radiation is described, for single shot, nondestructive measurement of the electron beam bunch length [2,3]. Thomson scattering based beam monitoring techniques are discussed which, through analysis of the radiated beam properties, allow non-destructive detailed measurement of transverse and longitudinal distributions of relativistic electron beams [4]. Two new techniques are discussed which rely on non-linear optical mixing of laser radiation with electron bunch emission: differential optical gating (DOG) [5] and electron bunch length measurement in a storage ring based on sum-frequency generation [6

  10. Effects of collisions on linear and non-linear spectroscopic line shapes

    International Nuclear Information System (INIS)

    Berman, P.R.

    1978-01-01

    A fundamental physical problem is the determination of atom-atom, atom-molecule and molecule-molecule differential and total scattering cross sections. In this work, a technique for studying atomic and molecular collisions using spectroscopic line shape analysis is discussed. Collisions occurring within an atomic or molecular sample influence the sample's absorptive or emissive properties. Consequently the line shapes associated with the linear or non-linear absorption of external fields by an atomic system reflect the collisional processes occurring in the gas. Explicit line shape expressions are derived characterizing linear or saturated absorption by two-or three-level 'active' atoms which are undergoing collisions with perturber atoms. The line shapes may be broadened, shifted, narrowed, or distorted as a result of collisions which may be 'phase-interrupting' or 'velocity-changing' in nature. Systematic line shape studies can be used to obtain information on both the differential and total active atom-perturber scattering cross sections. (Auth.)

  11. Measurement of magnetically insulated line voltage using a Thomson Parabola Charged Particle Analyser

    International Nuclear Information System (INIS)

    Stanley, T.D.; Stinnett, R.W.

    1981-01-01

    The absence of direct measurements of magnetically insulated line voltage necessitated reliance on inferred voltages based on theoretical calculation and current measurements. This paper presents some of the first direct measurements of magnetically insulated transmission line peak voltages. These measurements were made on the Sandia National Laboratories HydraMITE facility. The peak voltage is measured by observing the energy of negative ions produced at the line cathode and accelerated through the line voltage. The ion energy and the charge-to-mass ratio are measured using the Thomson Parabola mass spectrometry technique. This technique uses parallel E and B fields to deflect the ions. The deflected ions are detected using a microchannel plate coupled to a phosphor screen and photographic film. The Thomson Parabola results are compared to Faraday Cup measurements and to calculated voltages based on current measurements. In addition, the significance of observed positive ions is discussed

  12. Mass- and energy-analysis of fast ion beams in PF-1000 by means of a Thomson spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Czaus, K.; Skladnik-Sadowska, E.; Malinowski, K.; Kwiatkowski, R.; Zebrowski, J. [The Andrzej Soltan Institute for Nuclear Studies - IPJ, 05-400 Otwock-Swierk (Poland); Sadowski, M.J. [The Andrzej Soltan Institute for Nuclear Studies - IPJ, 05-400 Otwock-Swierk (Poland)] [Institute of Plasma Physics and Laser Microfusion - IPPLM, 01-497 Warsaw (Poland); Zebrowski, J.; Karpinski, L.; Paduch, M.; Scholz, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion - IPPLM, 01-497 Warsaw (Poland); Garkusha, I.E. [Institute of Plasma Physics, NSC KIPT, 61-108 Kharkov (Ukraine)

    2011-07-01

    The paper describes measurements of energy spectra of ions emitted along the z-axis of the PF-1000 facility, which have been for the first time performed by means a miniature Thomson spectrometer during 480-kJ discharges with the deuterium filling. The recorded Thomson parabolas showed that the escaping deuterons have energies in the range of 25-1000 keV, while protons (originated from hydrogen remnants) have the population of about 2 orders smaller and energies within the range of 35-300 keV. This document is composed of a paper followed by a poster. (authors)

  13. Scattered X-ray beam nondestructive testing

    International Nuclear Information System (INIS)

    Harding, G.; Kosanetzky, J.

    1988-01-01

    X-ray scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered [pt

  14. Shape dependent resonance light scattering properties of gold nanorods

    International Nuclear Information System (INIS)

    Zhu Jian; Huang Liqing; Zhao Junwu; Wang Yongchang; Zhao Yanrui; Hao Limei; Lu Yimin

    2005-01-01

    Suspended gold nanorods with mean aspect ratio 2.5 have been synthesized via electrochemical method. Resonance scattering properties have been studied. Two scattering peaks fixed at 400 and 640 nm are due to the scattering of the gold nanorods via coupling to the transverse and longitudinal surface plasmon resonance. The quasi-static calculation results indicate that with the increasing aspect ratio of the nanorods, the longer wavelength scattering peak red shifts linearly and the shorter wavelength peak blue shifts non-linearly. When aspect ratio a/b = 1.0, ellipse degenerate to sphere and the two peaks unite into one peak at 450 nm

  15. Effects of temperature and salinity on light scattering by water

    Science.gov (United States)

    Zhang, Xiaodong; Hu, Lianbo

    2010-04-01

    A theoretical model on light scattering by water was developed from the thermodynamic principles and was used to evaluate the effects of temperature and salinity. The results agreed with the measurements by Morel within 1%. The scattering increases with salinity in a non-linear manner and the empirical linear model underestimate the scattering by seawater for S < 40 psu. Seawater also exhibits an 'anomalous' scattering behavior with a minimum occurring at 24.64 °C for pure water and this minimum increases with the salinity, reaching 27.49 °C at 40 psu.

  16. Calibration of a Thomson parabola ion spectrometer and Fujifilm imaging plate detectors for protons, deuterons, and alpha particles.

    Science.gov (United States)

    Freeman, C G; Fiksel, G; Stoeckl, C; Sinenian, N; Canfield, M J; Graeper, G B; Lombardo, A T; Stillman, C R; Padalino, S J; Mileham, C; Sangster, T C; Frenje, J A

    2011-07-01

    A Thomson parabola ion spectrometer has been designed for use at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) at the University of Rochester. This device uses parallel electric and magnetic fields to deflect particles of a given mass-to-charge ratio onto parabolic curves on the detector plane. Once calibrated, the position of the ions on the detector plane can be used to determine the particle energy. The position dispersion of both the electric and magnetic fields of the Thomson parabola was measured using monoenergetic proton and alpha particle beams from the SUNY Geneseo 1.7 MV tandem Pelletron accelerator. The sensitivity of Fujifilm BAS-TR imaging plates, used as a detector in the Thomson parabola, was also measured as a function of the incident particle energy over the range from 0.6 MeV to 3.4 MeV for protons and deuterons and from 0.9 MeV to 5.4 MeV for alpha particles. The device was used to measure the energy spectrum of laser-produced protons at MTW.

  17. Calibration of a Thomson parabola ion spectrometer and Fujifilm imaging plate detectors for protons, deuterons, and alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, C. G.; Canfield, M. J.; Graeper, G. B.; Lombardo, A. T.; Stillman, C. R.; Padalino, S. J. [Physics Department, SUNY Geneseo, Geneseo, New York 14454 (United States); Fiksel, G.; Stoeckl, C.; Mileham, C.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Sinenian, N.; Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2011-07-15

    A Thomson parabola ion spectrometer has been designed for use at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) at University of Rochester. This device uses parallel electric and magnetic fields to deflect particles of a given mass-to-charge ratio onto parabolic curves on the detector plane. Once calibrated, the position of the ions on the detector plane can be used to determine the particle energy. The position dispersion of both the electric and magnetic fields of the Thomson parabola was measured using monoenergetic proton and alpha particle beams from the SUNY Geneseo 1.7 MV tandem Pelletron accelerator. The sensitivity of Fujifilm BAS-TR imaging plates, used as a detector in the Thomson parabola, was also measured as a function of the incident particle energy over the range from 0.6 MeV to 3.4 MeV for protons and deuterons and from 0.9 MeV to 5.4 MeV for alpha particles. The device was used to measure the energy spectrum of laser-produced protons at MTW.

  18. Scattering Amplitudes via Algebraic Geometry Methods

    DEFF Research Database (Denmark)

    Søgaard, Mads

    Feynman diagrams. The study of multiloop scattering amplitudes is crucial for the new era of precision phenomenology at the Large Hadron Collider (LHC) at CERN. Loop-level scattering amplitudes can be reduced to a basis of linearly independent integrals whose coefficients are extracted from generalized...

  19. measurements by Thomson scattering system

    Indian Academy of Sciences (India)

    oirity in measuring the electron temperature (Te) and density (ne) in fusion plasma devices like tokamaks. ... by the plasma electrons is used for the measurements. .... will be in the photon integration mode and will be acquired by a computer.

  20. Acta Dermatovenerologica Alpina, Pannonica et Adriatica accepted for coverage in Thomson Reuters' Emerging Sources Citation Index (ESCI).

    Science.gov (United States)

    Poljak, Mario; Miljković, Jovan; Triglav, Tina

    2016-09-01

    Acta Dermatovenerologica Alpina, Pannonica et Adriatica (Acta Dermatovenerol APA) is the leading journal in dermatology and sexually transmitted infections in the region. Several important steps were taken during the last 25 years to improve the journal's quality, global visibility, and international impact. After a 1-year trial period, Thomson Reuters recently informed the editorial office that they had accepted Acta Dermatovenerol APA for coverage in Thomson Reuters' new index in the Web of Science Core Collection called the Emerging Sources Citation Index (ESCI). The coverage of Acta Dermatovenerol APA begins with the journal content published online in 2016; that is, from volume 25 onwards.

  1. High-order boundary integral equation solution of high frequency wave scattering from obstacles in an unbounded linearly stratified medium

    Science.gov (United States)

    Barnett, Alex H.; Nelson, Bradley J.; Mahoney, J. Matthew

    2015-09-01

    We apply boundary integral equations for the first time to the two-dimensional scattering of time-harmonic waves from a smooth obstacle embedded in a continuously-graded unbounded medium. In the case we solve, the square of the wavenumber (refractive index) varies linearly in one coordinate, i.e. (Δ + E +x2) u (x1 ,x2) = 0 where E is a constant; this models quantum particles of fixed energy in a uniform gravitational field, and has broader applications to stratified media in acoustics, optics and seismology. We evaluate the fundamental solution efficiently with exponential accuracy via numerical saddle-point integration, using the truncated trapezoid rule with typically 102 nodes, with an effort that is independent of the frequency parameter E. By combining with a high-order Nyström quadrature, we are able to solve the scattering from obstacles 50 wavelengths across to 11 digits of accuracy in under a minute on a desktop or laptop.

  2. Gravitational scattering of electromagnetic radiation

    Science.gov (United States)

    Brooker, J. T.; Janis, A. I.

    1980-01-01

    The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.

  3. Scattering Amplitudes via Algebraic Geometry Methods

    CERN Document Server

    Søgaard, Mads; Damgaard, Poul Henrik

    This thesis describes recent progress in the understanding of the mathematical structure of scattering amplitudes in quantum field theory. The primary purpose is to develop an enhanced analytic framework for computing multiloop scattering amplitudes in generic gauge theories including QCD without Feynman diagrams. The study of multiloop scattering amplitudes is crucial for the new era of precision phenomenology at the Large Hadron Collider (LHC) at CERN. Loop-level scattering amplitudes can be reduced to a basis of linearly independent integrals whose coefficients are extracted from generalized unitarity cuts. We take advantage of principles from algebraic geometry in order to extend the notion of maximal cuts to a large class of two- and three-loop integrals. This allows us to derive unique and surprisingly compact formulae for the coefficients of the basis integrals. Our results are expressed in terms of certain linear combinations of multivariate residues and elliptic integrals computed from products of ...

  4. General algebraic theory of identical particle scattering

    International Nuclear Information System (INIS)

    Bencze, G.; Redish, E.F.

    1978-01-01

    We consider the nonrelativistic N-body scattering problem for a system of particles in which some subsets of the particles are identical. We demonstrate how the particle identity can be included in a general class of linear integral equations for scattering operators or components of scattering operators. The Yakubovskii, Yakubovskii--Narodestkii, Rosenberg, and Bencze--Redish--Sloan equations are included in this class. Algebraic methods are used which rely on the properties of the symmetry group of the system. Operators depending only on physically distinguishable labels are introduced and linear integral equations for them are derived. This procedure maximally reduces the number of coupled equations while retaining the connectivity properties of the original equations

  5. Multiple scattering effects on the Linear Depolarization Ratio (LDR) measured during CaPE by a Ka-band air-borne radar

    Science.gov (United States)

    Iguchi, Toshio; Meneghini, Robert

    1993-01-01

    Air-borne radar measurements of thunderstorms were made as part of the CaPE (Convection and Precipitation/Electrification) experiment in Florida in July 1991. The radar has two channels, X-band (10 GHz) and Ka-band (34.5 GHz), and is capable of measuring cross-polarized returns as well as co-polarized returns. In stratiform rain, the cross-polarized components can be observed only at the bright band region and from the surface reflection. The linear depolarization ratios (LDR's) measured at X-band and Ka-band at the bright band are nearly equal. In convective rain, however, the LDR in Ka-band often exceeds the X-band LDR by several dB, and sometimes by more than 10 dB, reaching LDR values of up to -5 dB over heavy convective rain. For randomly oriented hydrometeors, such high LDR values cannot be explained by single scattering from non-spherical scattering particles alone. Because the LDR by single backscatter depends weakly on the wavelength, the difference between the Ka-band and X-band LDR's suggests that multiple scattering effects prevail in the Ka-band LDR. In order to test this inference, the magnitude of the cross-polarized component created by double scattering was calculated using the parameters of the airborne radar, which for both frequencies has beamwidths of 5.1 degrees and pulse widths of 0.5 microsecond. Uniform rain beyond the range of 3 km is assumed.

  6. Image processing methods for noise reduction in the TJ-II Thomson Scattering diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informatica y Automatica, UNED, Madrid 28040 (Spain); Farias, G. [Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Vega, J.; Pastor, I. [Asociacion EURATOM/CIEMAT para Fusion, Madrid 28040 (Spain)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We describe an approach in order to reduce or mitigate the stray-light on the images and show the exceptional results. Black-Right-Pointing-Pointer We analyze the parameters to take account in the proposed process. Black-Right-Pointing-Pointer We report a simplified exampled in order to explain the proposed process. - Abstract: The Thomsom Scattering diagnostic of the TJ-II stellarator provides temperature and density profiles. The CCD camera acquires images corrupted with noise that, in some cases, can produce unreliable profiles. The main source of noise is the so-called stray-light. In this paper we describe an approach that allows mitigation of the effects that stray-light has on the images: extraction regions with connected-components. In addition, the robustness and effectiveness of the noise reduction technique is validated in two ways: (1) supervised classification and (2) comparison of electron temperature profiles.

  7. Gibbs–Thomson Effect in Planar Nanowires: Orientation and Doping Modulated Growth

    KAUST Repository

    Shen, Youde; Chen, Renjie; Yu, Xuechao; Wang, Qijie; Jungjohann, Katherine L.; Dayeh, Shadi A.; Wu, Tao

    2016-01-01

    Epitaxy-enabled bottom-up synthesis of self-assembled planar nanowires via the vapor-liquid-solid mechanism is an emerging and promising approach toward large-scale direct integration of nanowire-based devices without postgrowth alignment. Here, by examining large assemblies of indium tin oxide nanowires on yttria-stabilized zirconia substrate, we demonstrate for the first time that the growth dynamics of planar nanowires follows a modified version of the Gibbs-Thomson mechanism, which has been known for the past decades to govern the correlations between thermodynamic supersaturation, growth speed, and nanowire morphology. Furthermore, the substrate orientation strongly influences the growth characteristics of epitaxial planar nanowires as opposed to impact at only the initial nucleation stage in the growth of vertical nanowires. The rich nanowire morphology can be described by a surface-energy-dependent growth model within the Gibbs-Thomson framework, which is further modulated by the tin doping concentration. Our experiments also reveal that the cutoff nanowire diameter depends on the substrate orientation and decreases with increasing tin doping concentration. These results enable a deeper understanding and control over the growth of planar nanowires, and the insights will help advance the fabrication of self-assembled nanowire devices. © 2016 American Chemical Society.

  8. Gibbs–Thomson Effect in Planar Nanowires: Orientation and Doping Modulated Growth

    KAUST Repository

    Shen, Youde

    2016-06-02

    Epitaxy-enabled bottom-up synthesis of self-assembled planar nanowires via the vapor-liquid-solid mechanism is an emerging and promising approach toward large-scale direct integration of nanowire-based devices without postgrowth alignment. Here, by examining large assemblies of indium tin oxide nanowires on yttria-stabilized zirconia substrate, we demonstrate for the first time that the growth dynamics of planar nanowires follows a modified version of the Gibbs-Thomson mechanism, which has been known for the past decades to govern the correlations between thermodynamic supersaturation, growth speed, and nanowire morphology. Furthermore, the substrate orientation strongly influences the growth characteristics of epitaxial planar nanowires as opposed to impact at only the initial nucleation stage in the growth of vertical nanowires. The rich nanowire morphology can be described by a surface-energy-dependent growth model within the Gibbs-Thomson framework, which is further modulated by the tin doping concentration. Our experiments also reveal that the cutoff nanowire diameter depends on the substrate orientation and decreases with increasing tin doping concentration. These results enable a deeper understanding and control over the growth of planar nanowires, and the insights will help advance the fabrication of self-assembled nanowire devices. © 2016 American Chemical Society.

  9. The application of computational thermodynamics and a numerical model for the determination of surface tension and Gibbs-Thomson coefficient of aluminum based alloys

    International Nuclear Information System (INIS)

    Jacome, Paulo A.D.; Landim, Mariana C.; Garcia, Amauri; Furtado, Alexandre F.; Ferreira, Ivaldo L.

    2011-01-01

    Highlights: → Surface tension and the Gibbs-Thomson coefficient are computed for Al-based alloys. → Butler's scheme and ThermoCalc are used to compute the thermophysical properties. → Predictive cell/dendrite growth models depend on accurate thermophysical properties. → Mechanical properties can be related to the microstructural cell/dendrite spacing. - Abstract: In this paper, a solution for Butler's formulation is presented permitting the surface tension and the Gibbs-Thomson coefficient of Al-based binary alloys to be determined. The importance of Gibbs-Thomson coefficient for binary alloys is related to the reliability of predictions furnished by predictive cellular and dendritic growth models and of numerical computations of solidification thermal variables, which will be strongly dependent on the thermophysical properties assumed for the calculations. A numerical model based on Powell hybrid algorithm and a finite difference Jacobian approximation was coupled to a specific interface of a computational thermodynamics software in order to assess the excess Gibbs energy of the liquid phase, permitting the surface tension and Gibbs-Thomson coefficient for Al-Fe, Al-Ni, Al-Cu and Al-Si hypoeutectic alloys to be calculated. The computed results are presented as a function of the alloy composition.

  10. Plane-wave scattering from half-wave dipole arrays

    DEFF Research Database (Denmark)

    Jensen, Niels E.

    1970-01-01

    A matrix equation for determination of plane-wave scattering from arrays of thin short-circuited dipoles of lengths about half a wavelength is derived. Numerical and experimental results are presented for linear, circular, and concentric circular arrays.......A matrix equation for determination of plane-wave scattering from arrays of thin short-circuited dipoles of lengths about half a wavelength is derived. Numerical and experimental results are presented for linear, circular, and concentric circular arrays....

  11. Scattering of electromagnetic waves by a traversable wormhole

    Directory of Open Access Journals (Sweden)

    B. Nasr Esfahani

    2005-09-01

    Full Text Available   Replacing the wormhole geometry with an equivalent medium using the perturbation theory of scattering and the Born approximation, we have calculated the differential scattering cross section of electromagnetic waves by a traversable wormhole. It is shown that scattering at long wavelenghts can essentially distinguish wormhole from ordinary scattering object. Some of the zeros of the scattering cross section are determined which can be used for estimating the radius of the throat of wormholes. The known result that in this kind of scattering the linear polarization remains unchanged is verified here.

  12. Memory sparing, fast scattering formalism for rigorous diffraction modeling

    Science.gov (United States)

    Iff, W.; Kämpfe, T.; Jourlin, Y.; Tishchenko, A. V.

    2017-07-01

    The basics and algorithmic steps of a novel scattering formalism suited for memory sparing and fast electromagnetic calculations are presented. The formalism, called ‘S-vector algorithm’ (by analogy with the known scattering-matrix algorithm), allows the calculation of the collective scattering spectra of individual layered micro-structured scattering objects. A rigorous method of linear complexity is applied to model the scattering at individual layers; here the generalized source method (GSM) resorting to Fourier harmonics as basis functions is used as one possible method of linear complexity. The concatenation of the individual scattering events can be achieved sequentially or in parallel, both having pros and cons. The present development will largely concentrate on a consecutive approach based on the multiple reflection series. The latter will be reformulated into an implicit formalism which will be associated with an iterative solver, resulting in improved convergence. The examples will first refer to 1D grating diffraction for the sake of simplicity and intelligibility, with a final 2D application example.

  13. Scatter factor corrections for elongated fields

    International Nuclear Information System (INIS)

    Higgins, P.D.; Sohn, W.H.; Sibata, C.H.; McCarthy, W.A.

    1989-01-01

    Measurements have been made to determine scatter factor corrections for elongated fields of Cobalt-60 and for nominal linear accelerator energies of 6 MV (Siemens Mevatron 67) and 18 MV (AECL Therac 20). It was found that for every energy the collimator scatter factor varies by 2% or more as the field length-to-width ratio increases beyond 3:1. The phantom scatter factor is independent of which collimator pair is elongated at these energies. For 18 MV photons it was found that the collimator scatter factor is complicated by field-size-dependent backscatter into the beam monitor

  14. Interaction of ionising radiations with matter

    International Nuclear Information System (INIS)

    Caudrelier, Olivier

    2010-01-01

    In a first part, this academic course addresses the interaction of non-charged particles with matter. The author more particularly addresses the interaction of a photon plasma with matter (attenuation of electromagnetic radiations, law of exponential attenuation, attenuation half value layer), the elementary phenomena of the interaction of a photon with matter (photoelectric effect, Compton effect, Thomson-Rayleigh scattering, materialisation, photo-nuclear reaction, prevalence domains, application in medical imagery), and the interaction of fast and slow neutrons with matter (elastic and inelastic scattering, radiative and non-radiative capture). The second part addresses the interaction of charged particles with matter. The author more particularly addresses the interaction with electrons present in the medium (ionization, excitation, stop efficiency, linear energy transfer, ionization linear density), the interaction with the nucleus (Bremsstrahlung), and the case of light particles (electrons) and of heavy particles (protons, alpha, fission products)

  15. Possible limits of plasma linear colliders

    Science.gov (United States)

    Zimmermann, F.

    2017-07-01

    Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency is also addressed.

  16. Enhancement of Chiroptical Signals by Circular Differential Mie Scattering of Nanoparticles

    OpenAIRE

    SeokJae Yoo; Q-Han Park

    2015-01-01

    We enhance the weak optical signals of small chiral molecules via circular differential Mie scattering (CDMS) of nanoparticles immersed in them. CDMS is the preferential Mie scattering of left- and right-handed circularly polarized light by nanoparticles whose sizes are about the same as the wavelength of light. Solving the Mie scattering theory for chiral media, we find that the CDMS signal of the particle is linearly proportional to the chirality parameter κ of the molecules. This linear am...

  17. Electromagnetic theory of plasma light scattering

    International Nuclear Information System (INIS)

    Bobin, J.L.

    1969-01-01

    The theory of light scattering by a plasma is formulated using Klimontovich's microscopic distribution functions and Landau method to solve linear kinetic equations. First, Salpeter's derivation and results are given for the spectrum of light scattered by a collisionless plasma. Then, the influence of collision is investigated through B.G.K. kinetic equation. (author) [fr

  18. Analytical description of photon beam phase spaces in inverse Compton scattering sources

    Directory of Open Access Journals (Sweden)

    C. Curatolo

    2017-08-01

    Full Text Available We revisit the description of inverse Compton scattering sources and the photon beams generated therein, emphasizing the behavior of their phase space density distributions and how they depend upon those of the two colliding beams of electrons and photons. The main objective is to provide practical formulas for bandwidth, spectral density, brilliance, which are valid in general for any value of the recoil factor, i.e. both in the Thomson regime of negligible electron recoil, and in the deep Compton recoil dominated region, which is of interest for gamma-gamma colliders and Compton sources for the production of multi-GeV photon beams. We adopt a description based on the center of mass reference system of the electron-photon collision, in order to underline the role of the electron recoil and how it controls the relativistic Doppler/boost effect in various regimes. Using the center of mass reference frame greatly simplifies the treatment, allowing us to derive simple formulas expressed in terms of rms momenta of the two colliding beams (emittance, energy spread, etc. and the collimation angle in the laboratory system. Comparisons with Monte Carlo simulations of inverse Compton scattering in various scenarios are presented, showing very good agreement with the analytical formulas: in particular we find that the bandwidth dependence on the electron beam emittance, of paramount importance in Thomson regime, as it limits the amount of focusing imparted to the electron beam, becomes much less sensitive in deep Compton regime, allowing a stronger focusing of the electron beam to enhance luminosity without loss of mono-chromaticity. A similar effect occurs concerning the bandwidth dependence on the frequency spread of the incident photons: in deep recoil regime the bandwidth comes out to be much less dependent on the frequency spread. The set of formulas here derived are very helpful in designing inverse Compton sources in diverse regimes, giving a

  19. The application of computational thermodynamics and a numerical model for the determination of surface tension and Gibbs-Thomson coefficient of aluminum based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jacome, Paulo A.D.; Landim, Mariana C. [Department of Mechanical Engineering, Fluminense Federal University, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Garcia, Amauri, E-mail: amaurig@fem.unicamp.br [Department of Materials Engineering, University of Campinas, UNICAMP, PO Box 6122, 13083-970 Campinas, SP (Brazil); Furtado, Alexandre F.; Ferreira, Ivaldo L. [Department of Mechanical Engineering, Fluminense Federal University, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil)

    2011-08-20

    Highlights: {yields} Surface tension and the Gibbs-Thomson coefficient are computed for Al-based alloys. {yields} Butler's scheme and ThermoCalc are used to compute the thermophysical properties. {yields} Predictive cell/dendrite growth models depend on accurate thermophysical properties. {yields} Mechanical properties can be related to the microstructural cell/dendrite spacing. - Abstract: In this paper, a solution for Butler's formulation is presented permitting the surface tension and the Gibbs-Thomson coefficient of Al-based binary alloys to be determined. The importance of Gibbs-Thomson coefficient for binary alloys is related to the reliability of predictions furnished by predictive cellular and dendritic growth models and of numerical computations of solidification thermal variables, which will be strongly dependent on the thermophysical properties assumed for the calculations. A numerical model based on Powell hybrid algorithm and a finite difference Jacobian approximation was coupled to a specific interface of a computational thermodynamics software in order to assess the excess Gibbs energy of the liquid phase, permitting the surface tension and Gibbs-Thomson coefficient for Al-Fe, Al-Ni, Al-Cu and Al-Si hypoeutectic alloys to be calculated. The computed results are presented as a function of the alloy composition.

  20. How many accelerograms to use and how to deal with scattering for transient non-linear seismic computations?

    International Nuclear Information System (INIS)

    Viallet, E.; Heinfling, G.

    2005-01-01

    Due to increased potentialities of computers, it is nowadays possible to perform dynamic non-linear computation of structures to evaluate their ultimate behavior under seismic loads using refined finite element models. Nevertheless, one key parameter for such complex computations is the input load (i.e. input time histories) which may lead to important discrepancies in the results and therefore difficulties to deal with for engineering purpose (variability, number of time histories to use...). In this situation, the number of accelerograms to be used and the way to deal with the results is to be carefully assessed. The objective of this study is to give some elements concerning (i) the number of accelerograms to be used for transient non-linear computations and (ii) the way to account for scattering of results. For this purpose, some simplified non-linear models are used. These models represent characteristic types of non-linearities such as : - Reinforce concrete (RC) structure model (with plastic non-linearity), - PWR core model (with impact non-linearity). For each type of non-linearity, different sets of accelerograms are used (artificial and natural ones). Each set is composed of a relatively high number of accelerograms in order to get proper trends. The results are expressed in term of average and standard deviation values of the characteristic parameters for each non-linearity (i.e. ductility drift for RC structure model and impact force for PWR core model). The results show that, a relatively large number of time histories may be necessary to get proper predictions of the average value of the characteristic non-linear parameter under consideration. In that situation, it should be difficult to deal with such a result for complex studies on reel structures. Nevertheless, it may be necessarily to perform transient non-linear seismic computations for design analyses but with a reduced number of calculations. For this purpose, the previous results are analyzed