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Sample records for multipoint thomson scattering

  1. Upgraded multipulse laser and multipoint Thomson scattering diagnostics on EAST.

    PubMed

    Zang, Qing; Zhao, Junyu; Yang, Li; Hu, Qingsheng; Xi, Xiaoqi; Dai, Xingxing; Yang, Jianhua; Han, Xiaofeng; Li, Mengting; Hsieh, C L

    2011-06-01

    Recently a new Thomson scattering diagnostic system was upgraded in EAST tokamak experiment using a multipulse Nd:YAG (neodymium-yttrium aluminium garnet) laser and a multipoint observation volumes. This diagnostic uses a new optical laser alignment technique that was made to determine accurately the laser position, and a new lens collection system that enables the measurement of wider plasma's object. A composite control system made we can get the results in several seconds. Furthermore, a new data processing method was adopted for much exact results.

  2. HT-7 Multipoint Nd Laser Thomson Scattering Apparatus

    NASA Astrophysics Data System (ADS)

    Mao, Jian-shan; Zhao, Jun-yu; Li, Ya-dong; Xie, Ai-gen; Fang, Zhi-sheng; V, Sannikov; A, Gorshkov

    2001-04-01

    A compact, low cost, multipoint Thomson scattering diagnostic system for HT-7 superconducting tokamak has been in operation since 1999. Its capability of measuring electron temperatures is in the range of 200 eV to 2 keV at a density of a few times 1012 cm-3, with a spatial resolution of 2.4 cm for 5 spatial points and a temporal resolution of 1 ms similar 1 s for 8 time points. The main components of the diagnostic system include a 20-25 J Nd:glass laser with 35 ns pulse width (8 pulses per burst), a KDP frequency-doubling unit, spherical mirrors of multipass input optical system, a wide-angle collection objective, a bandpass glass filter for reducing the stray light to zero, a f/2.5 polychromator, a fiberglass collimator, a photomultiplier's box with electronic preamplifier, high gain and high signal/noise ratio, CAMAC data acquisition and so on. The multipass optical system has been successful at increasing the quantity of scattered photons by passing the probing laser beam 10 times through the plasma under investigation. The HT-7 Thomson scattering diagnostic has provided successfully the information on two-dimensional electron temperature in the plasma of HT-7 tokamak with LHCD and IBW.

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

    SciTech Connect

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

    2016-08-12

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

  4. Multipoint Thomson scattering diagnostic for the ETE tokamak

    NASA Astrophysics Data System (ADS)

    Berni, L. A.; Alonso, M. P.; Oliveira, R. M.

    2004-10-01

    To measure the electron temperature and plasma density profiles on the Experimento Tokamak Esférico tokamak a multiplexed Thomson scattering diagnostic was implemented. The diagnostic is based on a 10 J ruby laser and a single five spectral channel filter polychromator. A collection lens with f/6.3 relay the scattered light from 23 spatial points to optical fibers. The fibers have a monotonous increasing length and are inserted into the polychromator. Between the collection lens and each fiber optic we have a microlens to match the numerical aperture and to enlarge the plasma observation volume. This work describes the project, the simulations, and the preliminary results obtained with the first four optical fibers.

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

    SciTech Connect

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

    2016-09-16

    This public data set contains openly-documented, machine readable digital research data corresponding to figures published in D.J. Schlossberg et. al., 'A Novel, Cost-Effective, Multi-Point Thomson Scattering System on the Pegasus Toroidal Experiment,' Rev. Sci. Instrum. 87, 11E403 (2016).

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

    NASA Astrophysics Data System (ADS)

    Miller, Jared; Diallo, Ahmed; Leblanc, Benoit

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2016-11-01

    A novel, cost-effective, multi-point Thomson scattering system has been designed, implemented, and operated on the Pegasus Toroidal Experiment. Leveraging advances in Nd:YAG lasers, high-efficiency volume phase holographic transmission gratings, and increased quantum-efficiency Generation 3 image-intensified charge coupled device (ICCD) cameras, the system provides Thomson spectra at eight spatial locations for a single grating/camera pair. The on-board digitization of the ICCD camera enables easy modular expansion, evidenced by recent extension from 4 to 12 plasma/background spatial location pairs. Stray light is rejected using time-of-flight methods suited to gated ICCDs, and background light is blocked during detector readout by a fast shutter. This ∼10(3) reduction in background light enables further expansion to up to 24 spatial locations. The implementation now provides single-shot Te(R) for ne > 5 × 10(18) m(-3).

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

    DOE PAGES

    Schlossberg, David J.; Bodner, Grant M.; Bongard, Michael W.; ...

    2016-09-16

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

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

    DOE PAGES

    Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.; ...

    2016-08-12

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2016-11-01

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

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

    SciTech Connect

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

    2016-09-16

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

  14. Thomson scattering from laser plasmas

    SciTech Connect

    Moody, J D; Alley, W E; De Groot, J S; Estabrook, K G; Glenzer, S H; Hammer, J H; Jadaud, J P; MacGowan, B J; Rozmus, W; Suter, L J; Williams, E A

    1999-01-12

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

  15. Scaling Thomson scattering to big machines

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  16. Thomson scattering at general fusion

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Parfeniuk, D.

    2016-11-01

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

  17. Quantum theory of Thomson scattering

    NASA Astrophysics Data System (ADS)

    Crowley, B. J. B.; Gregori, G.

    2014-12-01

    The general theory of the scattering of electromagnetic radiation in atomic plasmas and metals, in the non-relativistic regime, in which account is taken of the Kramers-Heisenberg polarization terms in the Hamiltonian, is described from a quantum mechanical viewpoint. As well as deriving the general formula for the double differential Thomson scattering cross section in an isotropic finite temperature multi-component system, this work also considers closely related phenomena such as absorption, refraction, Raman scattering, resonant (Rayleigh) scattering and Bragg scattering, and derives many essential relationships between these quantities. In particular, the work introduces the concept of scattering strength and the strength-density field which replaces the normal particle density field in the standard treatment of scattering by a collection of similar particles and it is the decomposition of the strength-density correlation function into more familiar-looking components that leads to the final result. Comparisons are made with previous work, in particular that of Chihara [1].

  18. Alpha particle collective Thomson scattering in TFTR

    SciTech Connect

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

    1993-11-01

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

  19. Thomson scattering on inhomogeneous targets.

    PubMed

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

    2010-11-01

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

  20. Calibrations of the LHD Thomson scattering system

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  1. Radiation Reaction and Thomson Scattering

    SciTech Connect

    Koga, James

    2007-07-11

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

  2. Theory of Thomson scattering in inhomogeneous media

    PubMed Central

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

    2016-01-01

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

  3. Theory of Thomson scattering in inhomogeneous media

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  4. Thomson Scattering Measurements on HIT-SI3

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Berni, L. A.; Albuquerque, B. F. C.

    2010-12-01

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

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

    PubMed

    Berni, L A; Albuquerque, B F C

    2010-12-01

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

  7. Experimental observation of multiphoton Thomson scattering

    NASA Astrophysics Data System (ADS)

    Yan, Wenchao; Golovin, Grigory; Fruhling, Colton; Haden, Daniel; Zhang, Ping; Zhang, Jun; Zhao, Baozhen; Liu, Cheng; Chen, Shouyuan; Banerjee, Sudeep; Umstadter, Donald

    2016-10-01

    With the advent of high-power lasers, several multiphoton processes have been reported involving electrons in strong fields. For electrons that were initially bound to atoms, both multiphoton ionization and scattering have been reported. However, for free electrons, only low-order harmonic generation has been observed until now. This limitation stems from past difficulty in achieving the required ultra-high-field strengths in scattering experiments. Highly relativistic laser intensities are required to reach the multiphoton regime of Thomson scattering, and generate high harmonics from free electrons. The scaling parameter is the normalized vector potential (a0). Previous experiments have observed phenomena in the weakly relativistic case (a0 >> 1). In ultra-intense fields (a0 >>1), the anomalous electron trajectory is predicted to produce a spectrum characterized by the merging of multiple high-order harmonic generation into a continuum. This may be viewed as the multiphoton Thomson scattering regime analogous to the wiggler of a synchrotron. Thus, the light produced reflects the electrons behavior in an ultra-intense lase field. We discuss the first experiments in the highly relativistic case (a0 15). This material is based upon work supported by NSF No. PHY-153700; US DOE, Office of Science, BES, # DE-FG02-05ER15663; AFOSR # FA9550-11-1-0157; and DHS DNDO # HSHQDC-13-C-B0036.

  8. MFTF Thomson scattering: a system study

    SciTech Connect

    Frank, A.M.

    1980-09-11

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

  9. Design of C-2W Thomson Scattering System

    NASA Astrophysics Data System (ADS)

    Zhai, Kan; Schindler, Tania; Zhang, Helen; Walters, Kurt; Thompson, Matthew; TAE Team

    2016-10-01

    A suite of multi-point Thomson scattering systems is now being designed and built in parallel with the construction of the C-2W FRC experimental device, which is expected to have a wide range of electron temperature Te and density ne from edge to center region at different operational phases. The suite consists of two sub-systems that measure Te and ne profiles at the C-2W central plane and at the jet region. A high-repetition rate Nd:YAG laser is planned for the central plane subsystem for time-resolved profile measurement at 1 kHz. The central plane and jet region subsystems have their own specially-designed collection optics that image 16 and 5 radial points along the laser-beam path onto corresponding surfaces of fiber bundles, which will then relay the collected laser light into dispersing polychromators. The polychromators are designed with five spectral channels with four channels optimized and dedicated to Te measurement and one channel dedicated to Rayleigh scattering calibration for ne measurement. Detail system design and layout of lasers, beam transportation and stray light control, collection optics and fiber optics, dispersion and detection system and its spectral calibration setup will be presented.

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

    SciTech Connect

    Byung Yunn

    2006-02-21

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  12. Thomson Scattering Results from General Fusion's SPECTOR

    NASA Astrophysics Data System (ADS)

    Young, William

    2016-10-01

    General Fusion has been characterizing and optimizing a new spherical tokamak based device, SPECTOR, which has demonstrated electron temperatures as high as 350 eV. This new device is intended for testing of spherically symmetric compression. Thomson scattering diagnostic is installed on an uncompressed, but heavily diagnosed version of the device, as the compression method precludes some diagnostics. Temperature and density measurements are made at four spatial positions with upcoming plans to expand to six spatial positions. The diagnostic uses a 532 nm Nd:YAG laser and an imaging spectrometer with photomultiplier tube based detector. Other planned upgrades include camera and fiber based alignment monitoring, and multi-pass configuration reusing the laser pulse to increase the scattered light signal.

  13. Double pulse Thomson scattering system at RTP

    SciTech Connect

    Beurskens, M.N.; Barth, C.J.; Chu, C.C.; Donne, A.J.; Herranz, J.A.; Lopes Cardozo, N.J.; van der Meiden, H.J.; Pijper, F.J.

    1997-01-01

    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10{endash}800 {mu}s, max. 2{times}12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV{endash}7 keV can be determined with an accuracy as good as 2{percent}{endash}3{percent} for electron densities of 10{sup 20} m{sup {minus}3}, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. {copyright} {ital 1997 American Institute of Physics.}

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

    SciTech Connect

    McLean, A. G. Soukhanovskii, V. A.; Allen, S. L.; Carlstrom, T. N.; LeBlanc, B. P.; Ono, M.; Stratton, B. C.

    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.

  15. Implementation of a Thomson Scattering Diagnostic on Pegasus

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    The multipoint Thomson scattering system on PEGASUS will diagnose point-source helicity-driven plasmas, including dominant particle transport mechanisms and sources of helicity dissipation. Helicity-driven plasmas are estimated to have áTe ñ ~ 50 eV for stochastic field line confinement and ~200 eV for standard Ohmic closed flux surface confinement. To accurately characterize these regimes, a novel system is being designed, installed, and calibrated. A Nd:YAG laser is frequency doubled to provide a 9 ns, 2 J pulse radially across the plasma. Remote alignment of steering mirrors can be performed between shots along the 6 m length of the external laser beam-line. The 532 nm laser beam is focused to a <= 3 mm diameter beam within the plasma. Plasma background measurements are made simultaneously with data collection. A custom optical system collects signal from >70% of the plasma cross-section with 1.4 cm radial resolution. Optical fibers relay light to a high-efficiency volume phase holographic grating spectrometer coupled to a high quantum efficiency image intensified CCD camera, gated at >= 2 ns. Signal levels for plasmas with ne >1018 m-3 and 10 eV

  16. Radial resolution enhancement of the NSTX Thomson scattering diagnostica)

    NASA Astrophysics Data System (ADS)

    LeBlanc, B. P.; Diallo, A.; Labik, G.; Stevens, D. R.

    2012-10-01

    Current magnetic confinement plasma physics research has increased the demand for radial resolution in profile diagnostics, in particular in the edge and pedestal regions. On NSTX, an upgrade of the existing multi-point Thomson scattering diagnostic has been implemented in order to respond to the research program needs. Twelve new radial channels have been added bringing the total number of positions to 42. Four previously un-instrumented fiber bundles were put in service. Eight existing "active" fiber bundles were divided in two sub-bundles each in order to increase spatial resolution. Twelve radial channels now cover the pedestal region with a resolution near one centimeter. Fifteen radial channels cover the core and internal transport barrier regions. Two additional channels were added, one near the inner edge and one in the outer scrape-off layer. The intersection of the focused viewing optics field of view with a finite-width laser beam results in major-radius cross talk between adjacent fiber sub-bundles. A discussion and calculation of the cross talk will be presented.

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

    SciTech Connect

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

    2014-11-15

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

  18. Thomson Scattering at FLASH - Status Report

    SciTech Connect

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

    2007-11-28

    The basic idea is to implement Thomson scattering with free electron laser (FEL) radiation at near-solid density plasmas as a diagnostic method which allows the determination of plasma temperatures and densities in the warm dense matter (WDM) regime (free electron density of n{sub e} = 10{sup 21}-10{sup 26} cm{sup -3} with temperatures of several eV). The WDM regime [1] at near-solid density (n{sub e} = 10{sup 21}-10{sup 22} cm{sup -3}) is of special interest because, it is where the transition from an ideal plasma to a degenerate, strongly coupled plasma occurs. A systematic understanding of this largely unknown WDM domain is crucial for the modeling and understanding of contemporary plasma experiments, like laser shock-wave or Z-pinch experiments as well as for inertial confinement fusion (ICF) experiments as the plasma evolution follows its path through this domain.

  19. A compact multichannel spectrometer for Thomson scattering.

    PubMed

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

    2012-10-01

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

  20. Thomson Scattering on NSTX-U

    NASA Astrophysics Data System (ADS)

    Leblanc, Benoit; Diallo, Ahmed

    2016-10-01

    The MPTS Thomson scattering diagnostic has been supporting NSTX-U since its start of operation in August 2015. At the time of this writing more than 1000 plasmas have been documented. While most MPTS elements from ``NSTX'' were reutilized, significant changes were necessitated: The laser-beam path was re-aimed in order to accommodate for the larger center-stack diameter of NSTX-U. The presence of a new neutral beam box required the introduction of mirror optics in order to dump the laser beams away from the measurement region. The FY2016 run marks the start of operation of a previously installed upgrade to 42 channels. Details of the new MPTS configuration will be given and experimental results will be presented. Future plans will also be discussed. This work was funded by DOE contract DE-AC02-09CH11466.

  1. Dense Matter Characterization by X-ray Thomson Scattering

    SciTech Connect

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

    2000-12-29

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

  2. Thomson scattering on ELMO Bumpy Torus

    SciTech Connect

    Cobble, J.A.

    1985-04-01

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

  3. Dust in FTU with the Thomson Scattering diagnostic

    SciTech Connect

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

    2008-09-07

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

  4. Observation of relativistic effects in collective Thomson scattering

    SciTech Connect

    Ross, J S; Glenzer, S H; Palastro, J P; Pollock, B B; Price, D; Divol, L; Tynan, G R; Froula, D H

    2009-10-08

    We observe relativistic modifications to the Thomson scattering spectrum in a traditionally classical regime: v{sub osc}/c = eE{sub 0}/cm{omega}{sub 0} << 1 and T{sub e} < 1 keV. The modifications result from scattering off electron-plasma fluctuations with relativistic phase velocities. Normalized phase velocities v/c between 0.03 and 0.12 have been achieved in a N{sub 2} gas-jet plasma by varying the plasma density from 3 x 10{sup 18} cm{sup -3} to 7 x 10{sup 19} cm{sup -3} and electron temperature between 85 eV and 700 eV. For these conditions, the complete temporally resolved Thomson scattering spectrum including the electron and ion features has been measured. A fully relativistic treatment of the Thomson scattering form factor has been developed and shows excellent agreement with the experimental data.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  6. Studying Filamentary Currents with Thomson Scattering on MST

    NASA Astrophysics Data System (ADS)

    den Hartog, D. J.; Young, W. C.; Kubala, S. Z.

    2016-10-01

    The MST reversed-field pinch plasma generates bursts of toroidally localized magnetic activity associated with m = 0 modes resonant at the reversal surface near the plasma edge. Previously, using data from an array of edge magnetic probes, these bursts were connected to poloidal current filaments. Now the MST Thomson scattering diagnostic is being used to measure the net drift in the electron distribution due to these currents. An additional long-wavelength spectral bin has been added to several Thomson scattering polychromators, in addition to 5-7 pre-existing short wavelength spectral bins, to improve discrimination between shifted vs. broadened spectra. The bursts are examined in plasma conditions that display spontaneous periods of low tearing-mode activity, with higher confinement and higher temperatures that improve Thomson scattering measurement performance. This work is supported by the U.S. Department of Energy and the National Science Foundation.

  7. Plasma Jet Interaction with Thomson Scattering Probe Laser

    NASA Astrophysics Data System (ADS)

    Byvank, Tom; Banasek, Jacob; Potter, William; Kusse, Bruce

    2016-10-01

    Thomson scattering systems can diagnose plasma temperatures and velocities. When probing a plasma jet with the Thomson scattering laser, we observe a laser-plasma interaction that inputs energy into the plasma jet. The absorbed energy causes a bubble of low density ( 5*1017 cm-2) in the jet (unperturbed 1018 cm-2). A pulsed power machine (1 MA peak current, 100 ns rise time) with a radial foil (15 μm thick Al) configuration generates the plasma jet. We compare the effects of using 10 J and 1 J laser energies, for which the 10 J laser is a larger perturbation. We discuss how the interaction affects the Thomson scattering temperature and velocity measurements. Work supported by National Nuclear Security Administration (NNSA) Stewardship Sciences Academic Programs under Department of Energy (DOE) Cooperative Agreement DE-NA0001836 and National Science Foundation (NSF) Grant PHY-1102471.

  8. LIDAR Thomson scattering for advanced tokamaks. Final report

    SciTech Connect

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

    1996-03-18

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

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

    SciTech Connect

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

    2000-07-18

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

  10. Thomson scattering in a magnetic field. II - Arbitrary field orientation

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    This paper presents solutions to the equation of transfer for Thomson scattering in a constant magnetic field of arbitrary orientation. Results from several atmospheres are combined to give the flux from a dipole star. The results are compared to the polarization data of the magnetic white dwarf Grw + 70 deg 8247. The fit is good, though it implies a very large polarization in the ultraviolet. Thomson scattering is not thought to be an important opacity source in white dwarfs, so the good fit is either fortuitous or is perhaps explained by assuming the magnetic field affects the polarization processes in all opacities similarly.

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

    PubMed

    Bilkova, P; Melich, R; Aftanas, M; Böhm, P; Sestak, D; Jares, D; Weinzettl, V; Stöckel, J; Hron, M; Panek, R; Scannell, R; Walsh, M J

    2010-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  13. Thomson scattering from a three-component plasma

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.

    2014-02-01

    A model for a three-component plasma consisting of two distinct ionic species and electrons is developed and applied to study x-ray Thomson scattering. Ions of a specific type are assumed to be identical and are treated in the average-atom approximation. Given the plasma temperature and density, the model predicts mass densities, effective ionic charges, and cell volumes for each ionic type, together with the plasma chemical potential and free-electron density. Additionally, the average-atom treatment of individual ions provides a quantum-mechanical description of bound and continuum electrons. The model is used to obtain parameters needed to determine the dynamic structure factors for x-ray Thomson scattering from a three-component plasma. The contribution from inelastic scattering by free electrons is evaluated in the random-phase approximation. The contribution from inelastic scattering by bound electrons is evaluated using the bound-state and scattering wave functions obtained from the average-atom calculations. Finally, the partial static structure factors for elastic scattering by ions are evaluated using a two-component version of the Ornstein-Zernike equations with hypernetted chain closure, in which electron-ion interactions are accounted for using screened ion-ion interaction potentials. The model is used to predict the x-ray Thomson scattering spectrum from a CH plasma and the resulting spectrum is compared with experimental results obtained by Feltcher et al. [Phys. Plasmas 20, 056316 (2013), 10.1063/1.4807032].

  14. Advances in the FTU collective Thomson scattering system

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  15. Relativistic Electron Beams, Forward Thomson Scattering, and ``Raman'' Scattering

    NASA Astrophysics Data System (ADS)

    Simon, A.

    1999-11-01

    Experiments at LLE (see abstract by D. Hicks at this meeting) show that surprisingly high potentials (+0.5 to 2.0 MV) develop in plasmas irradiated by high-energy lasers. The highly conducting plasma will be a near equipotential and should attract return-current electrons in a radial beam-like distribution, especially in the outer low-density regions. This will initiate the BOT instability, creating large plasma waves with phase velocities close to c. Coherent Thomson scattering of the interaction beam from these waves must occur primarily in the forward direction. This will appear to be ``backward SRS'' upon reflection from a critical surface. We will show that the resulting spectrum is fairly broad and at short wavelengths. Collisional absorption of the scattered EM wave limits the reflectivity to low values (depending on the density scale length). Thus, a distinct difference exists between the spectrum for thick targets (nc surface present) and thin targets (gasbags, etc., from which primarily a narrow absolute-SRS backward emission occurs, at the peak density). The thick-target, reflected-wave angular distribution will be concentrated in the backward direction. The corresponding plasma-wave k-vector will be a fraction of k_0. The variation of the spectrum with potential and angle will be discussed. Comparison will be made with recent results at LLE and LLNL. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460, UR, and NYSERDA.

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

    SciTech Connect

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

    2012-05-04

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

  17. Upgraded divertor Thomson scattering system on DIII-D

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

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

    2012-05-01

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

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

    SciTech Connect

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

    2004-10-01

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

  20. Laser Thomson scattering in a pulsed atmospheric arc discharge

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Adams, Steven

    2015-09-01

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

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

    SciTech Connect

    Giudicotti, L.

    2014-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  4. Thomson scattering diagnostic on the Compact Toroidal Hybrid Experiment

    NASA Astrophysics Data System (ADS)

    Traverso, Peter; Maurer, D. A.; Ennis, D. A.; Hartwell, G. J.

    2016-10-01

    A Thomson scattering system is being commissioned for the non-axisymmetric plasmas of the Compact Toroidal Hybrid (CTH), a five-field period current-carrying torsatron. The system takes a single point measurement at the magnetic axis to both calibrate the two- color soft x-ray Te system and serve as an additional diagnostic for the V3FIT 3D equilibrium reconstruction code. A single point measurement will reduce the uncertainty in the reconstructed peak pressure by an order of magnitude for both current-carrying plasmas and future gyrotron-heated stellarator plasmas. The beam, generated by a frequency doubled Continuum 2 J, Nd:YaG laser, is passed vertically through an entrance Brewster window and a two-aperture optical baffle system to minimize stray light. The beam line propagates 8 m to the CTH device mid-plane with the beam diameter < 3 mm inside the plasma volume. Thomson scattered light is collected by two adjacent f/2 plano-convex condenser lenses and focused onto a custom fiber bundle. The fiber is then re-bundled and routed to a Holospec f/1.8 spectrograph to collect the red-shifted scattered light from 535-565 nm. The system has been designed to measure plasmas with core Te of 100 to 200 eV and densities of 5 ×1018 to 5 ×1019 m-3. Work supported by USDOE Grant DE-FG02-00ER54610.

  5. Imaging Thomson scattering measurements of radiatively heated Xe

    SciTech Connect

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

    2012-05-01

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

  6. Laser beam combiner for Thomson scattering core LIDAR.

    PubMed

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

    2010-10-01

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

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

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara

    1989-01-01

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

  8. Imaging Near-Earth Electron Densities Using Thomson Scattering

    DTIC Science & Technology

    2009-01-15

    the solar corona . The technique used is “white light” imaging of the visible portion of the solar radiative flux as it undergoes Thomson scattering...toward the ecliptic pole. We also examined the output from the Koutchmy-Lamy model of the solar F- corona (Koutchmy and Lamy 1985), which is another...designation of the zodiacal light used in solar physics. Figure 9 shows the bright- ness of the F- corona as a function of radial distance from the Sun in

  9. Development of a Multichannel Spectrometer for the Thomson Scattering Diagnostic on Pegasus

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    To explore electron transport in helicity-driven discharges and investigate edge stability, a multi-point Thomson scattering diagnostic is being developed. Red-shifted scattered light from the Nd:YAG laser, 532-632 nm, is imaged using a custom lens coupled to fiber optic cables capable of imaging 1.4 cm along the length of the laser beam. Initially 1 spectrometer, containing up to 8 radial spatial points will be available for detection, with an upgrade to 3 spectrometers planned in the near future. New high efficiency volume phase holographic gratings, with > 75% transmission, allow for a simplified spectrometer design. This provides high optical throughput and readily couples to new high quantum efficiency (~45%) image intensified CCD cameras for multichannel design. These cameras can be gated to as low as 2 ns. The two gratings fabricated for this system (2971 lines/mm and 2072 lines/mm) cover the design temperature range of 10 eV to 1 keV. Completing the spectrometer are high quality lenses with focal lengths of 130 cm on the collimating lens and 85 cm on the exit lens. This design has a spectral range compatible with the blue shift from a conventional ruby laser and allows for a compact, simplified system. Work supported by US DOE Grant DE-FG02-96ER54375.

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

    NASA Astrophysics Data System (ADS)

    Carbone, Emile; Nijdam, Sander

    2015-01-01

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

  11. Material Assessment for ITER's Collective Thomson Scattering first mirror

    SciTech Connect

    Santos, R.; Policarpo, H.; Goncalves, B.; Varela, P.; Nonboel, E.; Klinkby, E.; Lauritzen, B.; Romanets, Y.; Luis, R.; Vaz, P.

    2015-07-01

    The International Thermonuclear Energy Reactor (ITER) Collective Thomson Scattering (CTS) system is a diagnostic instrument that measures plasma density and velocity through Thomson scattering of microwave radiation. Some of the key components of the CTS are quasi-optical mirrors that are used to produce astigmatic beam patterns, which have impact on the strength and spatial resolution of the diagnostic signal. The mirrors are exposed to neutron radiation, which may alter the quality of the signal received. In this work, three different materials (molybdenum (Mo), stainless steel 316 (SS-316) and tungsten (W)) are considered for the first mirror of the CTS. The objective is to access which of the material studied are best suited for this mirror, considering different neutron radiation loads simulated scenarios defined by ITER, based on the resultant stresses and temperature distributions. For it, the neutron irradiation, and subsequent heat-load on the mirrors are simulated using the Monte Carlo N-Particle (MCNP) code. Based on the MCNP heat-load results, transient thermal-structural Finite Element Analysis (FEA) of the mirror over a 400 s discharge, with and without cooling on the rear side, are conducted using in commercial FEA software ANSYS. Results show that of the tested materials Mo and W are the most suitable material for this application. Even though, this study does not yet consider the variation of the material properties with temperature, it presents a quick initial satisfactory assessment that may be considered in subsequent and more complex analysis. (authors)

  12. Conceptual design of a polarimetric Thomson scattering diagnostic in ITER

    NASA Astrophysics Data System (ADS)

    Giudicotti, L.; Bassan, M.; Orsitto, F. P.; Pasqualotto, R.; Kempenaars, M.; Flanagan, J.

    2016-01-01

    Polarimetric Thomson scattering (TS) is a novel diagnostic technique proposed as an alternative to conventional (spectral) TS, for the measurement of the electron temperature Te and density ne in very hot fusion plasmas. Contrary to spectral TS, which is based on the reconstruction of the Doppler broadened frequency spectrum, in polarimetric TS Te is determined from the depolarization of the scattered radiation. The technique is suitable for ITER, where it is expected to be competitive with conventional spectral TS for measurements in the highest Te range, specially in backward-like conditions with the scattering angle 90° ll θ <= 180°. In this paper we consider a hypothetical polarimetric TS diagnostic for ITER and evaluate its performance for the θ = 145° scattering condition typical of the core TS system and also for a different scattering geometry in which, using a tangential laser beam, the central region of the ITER plasma can be observed under a scattering angle θ ~ 75°. In both cases we calculate the expected errors on the measured Te and ne that can be obtained with a simple, two-channel polarimeter, and taking into account that only a fraction of the TS wavelength spectrum is detected. In both cases the expected performances are compared with those of the conventional spectral core TS diagnostic to determine the plasma conditions in which the polarimetric technique is more advantageous. A measurement of the depolarization effect of the TS radiation using the JET High Resolution TS system of JET is also discussed.

  13. Observations of stimulated Raman scattering using simultaneous Thomson scattering, fast electron spectroscopy, and infrared diagnostics

    SciTech Connect

    McIntosh, G.; Meyer, J.; Yazhou, Z.

    1986-10-01

    Stimulated Raman scattering (SRS) in a CO/sub 2/ laser(lambda/sub 0/ -- 10.6 ..mu..m) produced plasma has been studied experimentally. The enhanced electron plasma wave (epw) fluctuations observed with ruby laser Thomson scattering have been compared with the scattered infrared (IR) spectra and the high-energy (near 100 keV) electrons. No scattered IR light in the range 1.5lambda/sub 0/ Thomson scattered wave vector spectra.

  14. Thomson scattering in a magnetic field. I - Field along z

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    The Monte Carlo method is used here to solve the radiative transfer equation for Thomson scattering in a constant magnetic field perpendicular to the atmosphere. Emergent radiation and polarization are presented for various atmospheric thicknesses. The circular polarization peaks at frequencies near the cyclotron, omega(c), and for propagation direction along the field. At low field strengths, the circular polarization is roughly proportional to omega(c)/omega; the linear polarization is proportional to the square of omega(c)/omega and the amount of circular polarization present at each scatter and is therefore much smaller than the circular polarization. The linear polarization is large for propagation direction perpendicular to the magnetic field and at frequencies near the cyclotron and in the strong-field limit. The position angle of the linear polarization undergoes a rotation of 90 deg at a value of omega(c)/omega near the square root of three.

  15. Thomson Scattering Diagnostic Data Acquisition Systems for Modern Fusion Systems

    SciTech Connect

    Ivanenko, S.V.; Khilchenko, A.D.; Ovchar, V.K.; Zubarev, P.V.; Kvashnin, A.N.; Puryga, E.A.; Ivanova, A.A.; Kotelnikov, A.I.

    2015-07-01

    Uniquely designed complex data acquisition system for Thomson scattering diagnostic was developed. It allows recording short duration (3-5 ns) scattered pulses with 2 GHz sampling rate and 10-bit total resolution in oscilloscope mode. The system consists up to 48 photo detector modules with 0- 200 MHz bandwidth, 1-48 simultaneously sampling ADC modules and synchronization subsystem. The photo detector modules are based on avalanche photodiodes (APD) and ultra-low noise trans-impedance amplifiers. ADC modules include fast analog to digital converters and digital units based on the FPGA (Field- Programmable Gate Array) for data processing and storage. The synchronization subsystem is used to form triggering pulses and to organize the simultaneously mode of ADC modules operation. (authors)

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

    PubMed

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

    2016-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  18. The Thomson scattering system at Wendelstein 7-X

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  19. Dense Plasma Characterization by X-Ray Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Glenzer, Siegfried H.

    2001-10-01

    Solid-density plasmas close to the Fermi degenerate state are a fundamental state of matter that occurs in high energy density laboratory experiments. It has been a long-standing goal to study the microscopic properties of these dense plasmas because conventional diagnostic techniques and standard plasma theory that treat the interactions between particles as a small correction are not applicable. We have recently succeeded measuring the temperature of this previously unexplored regime of matter with a proof-of-principal experiment at the Omega laser facility at LLE, U. Rochester. We used spectrally-resolved 4.5-keV x-ray scattering from a solid-density beryllium plasma. The source is provided by a highly ionized resonance K-line from a Ti plasma. The sample is heated volumetrically by x-rays from another set of mid-Z plasmas produced by 10^15Wcm-2 laser beams. X-ray Thomson scattering provides for the first time detailed information on electron densities, temperature, and velocity distributions. In our experiments, we observe the Compton-downshifted spectral line that is broadened by the thermal motion of the electrons in the plasma indicating Te ≈ TF = 14 eV. The full range of dense plasmas, from Fermi degenerate, to strongly coupled, to high temperature ideal gas plasmas will now be accessible. For example, as the temperature is increased, the electron velocity distribution as measured by incoherent Thomson scattering will make a transition from a density-dependent parabolic Fermi distribution to the traditional Gaussian Boltzmann distribution. The technique has wide applications, ranging from studying the adiabat and compression of ICF fuels, to temperature measurements for radiatively heated foams. In addition, by accessing the collective scattering regime, basic dense plasma wave physics can be studied.

  20. Nonlinear Thomson scattering of an ultrashort laser pulse

    SciTech Connect

    Golovinski, P. A. Mikhin, E. A.

    2011-10-15

    The nonlinear scattering of an ultrashort laser pulse by free electrons is considered. The pulse is described in the 'Mexican hat' wavelet basis. The equation of motion for a charged particle in the field of a plane electromagnetic wave has an exact solution allowing, together with the instant spectrum approximation, the calculation of the intensity of nonlinear Thomson scattering for a high-intensity laser pulse. The spectral distribution of scattered radiation for the entire pulse duration is found by integrating with respect to time. The maximum of the emission spectrum of a free electron calculated in 10{sup 19}-10{sup 21} W/cm{sup 2} fields lies in the UV spectral region between 3 and 12 eV. A part of the continuous spectrum achieves high photon energies. One percent of the scattered energy for the field intensity 10{sup 20} W/cm{sup 2} is concentrated in the range h{omega} > 2.7 Multiplication-Sign 10{sup 2} eV, for a field intensity of 10{sup 21} W/cm{sup 2} in the range h{Omega} > 7.9 Multiplication-Sign 10{sup 2} eV, and for an intensity of 10{sup 22} W/cm{sup 2} in the range h{Omega} > 2.45 Multiplication-Sign 10{sup 5} eV. These results allow us to estimate nonlinear scattering as a source of hard X-rays.

  1. Thomson Scattering on exploding wires at 800 kA

    NASA Astrophysics Data System (ADS)

    Greenly, John; Seyler, Charles; Banasek, Jacob; Potter, William

    2016-10-01

    Laser Thomson scattering measurements have been carried out on a single 0.25 mm diameter Al wire load driven with an 800 kA, 100 ns risetime pulse on the COBRA pulsed power facility. The 527 nm, 10 J, 5 ns laser is brought to a line focus on a chord across the unstable, roughly cylindrical plasma column of the wire, which reaches 8mm outer diameter at 100 ns. The laser path is either on axis or 2mm or 4mm off axis. Scattered signals are collected on a fiber array yielding data across the laser path through the plasma. The scattered light is easily visible over the wire plasma self-emission. The scattered spectra have highly complex structures comprised of as many as four distinct spectral peaks spread over 1 nm in wavelength, both red-and blue-shifted. On axis, the laser does not reach the far side of the plasma, being totally absorbed and/or refracted out of its path. 2 mm off-axis the beam is severely refracted, probably from near the critical surface in the plasma, appearing in images taken with cameras 45 degrees off its entering path. The scattering should be in the collective regime, and analysis is underway to extract information on flow velocities and temperatures within the volume, of 0.5mm radius, imaged by each fiber. Work supported by US DOE NNSA Grant DE-NA0001855.

  2. Effects of turbulence on the Thomson scattering process in turbulent plasmas by the scattering of electromagnetic waves

    NASA Astrophysics Data System (ADS)

    Jung, Young-Dae

    2013-05-01

    The effects of turbulence on the Thomson scattering process are investigated in turbulent plasmas. The Thomson scattering cross section in turbulent plasmas is obtained by the fluctuation-dissipation theorem and plasma dielectric function as a function of the diffusion coefficient, wave number, and Debye length. It is demonstrated that the turbulence effect suppresses the Thomson scattering cross section. It is also shown that the turbulence effect on the Thomson scattering process decreases with increasing thermal energy. The dependence of the wave number on the total Thomson scattering cross section including the turbulent structure factor is also discussed. This paper is dedicated to the late Prof. P. K. Shukla in memory of exciting and stimulating collaborations on effective interaction potentials in various astrophysical and laboratory plasmas.

  3. Thomson Scattering Measurements During Local Helicity Injection in the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Local helicity injection (LHI) is a non-solenoidal startup technique currently being developed at the Pegasus Toroidal Experiment. In LHI, helicity is injected by compact, high-power current sources located in the plasma scrape off layer that drive bulk plasma current through magnetic reconnection. Investigations of the electron temperature and density evolution in LHI plasmas are being pursued using the multi-point Thomson scattering diagnostic on Pegasus. It has been expanded to provide a total of 24 spatial channels using a set of three high-throughput transmission gratings and intensified CCD cameras. Measurements have been made in two separate helicity injector configurations: a low-field-side (outboard midplane) configuration; and a high-field-side (lower divertor) configuration. Initial observations during injection showed 50

  4. Progress of microwave collective Thomson scattering in LHD

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    SciTech Connect

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

    2004-10-01

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

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

    PubMed

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

    2007-04-01

    A multipulse Nd:YAG (Yttrium aluminum garnet) Thomson scattering (TS) system is designed and developed for measuring electron temperature (T(e)) and density (n(e)) profiles of SST-1 tokamak. The system operates at vertical, divertor, and horizontal (midplane) regions of plasma and measures the electron temperature of 20 eV to 1.5 keV and density of 10(18)-10(19) m(-3). Six Nd:YAG lasers synchronized with external control is used to get three different temporal resolutions (30 Hz, 180 Hz, and 1 kHz). The entire system is laboratory tested for the stability of alignment and performance over a distance of 30 m. Different imaging lens assemblies are designed to image the scattered photons from each of the scattering region to an array of optical fibers. A low cost and compact five-channel interference filter polychromator is designed, fabricated, and tested for its image quality and the filter transmission characteristics. Detection system with an avalanche photodiode and required signal conditioning electronics is developed for detecting the scattered photons. A data acquisition and control module operating on PXI bus is developed for the real time data acquisition and system control. A detailed description of design and testing of TS subsystems is presented in this article.

  7. Pulse-burst laser systems for fast Thomson scattering (invited)

    SciTech Connect

    Den Hartog, D. J.; Ambuel, J. R.; Holly, D. J.; Robl, P. E.; Borchardt, M. T.; Falkowski, A. F.; Harris, W. S.; Parke, E.; Reusch, J. A.; Stephens, H. D.; Yang, Y. M.

    2010-10-15

    Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to ''pulse-burst'' capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.

  8. Pulse-burst laser systems for fast Thomson scattering (invited).

    PubMed

    Den Hartog, D J; Ambuel, J R; Borchardt, M T; Falkowski, A F; Harris, W S; Holly, D J; Parke, E; Reusch, J A; Robl, P E; Stephens, H D; Yang, Y M

    2010-10-01

    Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.

  9. Thomson scattering in high-intensity chirped laser pulses

    SciTech Connect

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

    2015-10-15

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

  10. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    SciTech Connect

    Ross, J. S. Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S.

    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.

  11. Calibration of a Thomson scattering diagnostic for fluctuation measurements

    SciTech Connect

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

    2008-10-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  13. Progress on Thomson scattering in the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  14. Thomson scattering on high pressure Hg discharge lamps

    NASA Astrophysics Data System (ADS)

    Zhu, X.; de Vries, N.; Kieft, E. R.; van der Mullen, J. J. A. M.; Haverlag, M.

    2005-06-01

    Thomson scattering (TS) experiments have been performed on high-pressure Hg discharge lamps. These lamps were filled with different amounts of Hg (15, 30, 50 and 70 mg) and were operating at different powers (150, 200 and 240 W) with a square-wave ballast. As in the previous studies (Zhu X et al 2004 J. Phys. D: Appl. Phys. 37 736-43) a triple grating spectrograph was used to suppress the false stray light and Rayleigh scattered photons. This set-up had to be modified for this special application. The collective TS spectra have been fitted using both a calibration using Raman scattering and a form fitting procedure. It was found that the electron temperature fluctuates around a certain value that seems rather constant in the central region. The value of electron temperature (Te) varies between 5500 and 7600 K in the central region (r <= 0.3 R). The spatial-averaged Te value increases with the lamp power. The electron density was found to be of the order of 1021 m-3 which is high at the centre and decreases as r increases. The ne value also increases with the lamp power. Moreover the results of TS are compared with those from x-ray absorption measurement. The comparison shows that the plasmas in such lamps are not in local thermal equilibrium in the sense that T_e\

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  16. A Thomson scattering diagnostic on the Pegasus Toroidal experiment.

    PubMed

    Schlossberg, D J; Schoenbeck, N L; Dowd, A S; Fonck, R J; Moritz, J I; Thome, K E; Winz, G R

    2012-10-01

    By exploiting advances in high-energy pulsed lasers, volume phase holographic diffraction gratings, and image intensified CCD cameras, a new Thomson scattering system has been designed to operate from 532 - 592 nm on the Pegasus Toroidal Experiment. The system uses a frequency-doubled, Q-switched Nd:YAG laser operating with an energy of 2 J at 532 nm and a pulse duration of 7 ns FWHM. The beam path is < 7m, the beam diameter remains ≤ 3 mm throughout the plasma, and the beam dump and optical baffling is located in vacuum but can be removed for maintenance by closing a gate valve. A custom lens system collects scattered photons from 15 cm < R(maj) < 85 cm at ~F∕6 with 14 mm radial resolution. Initial measurements will be made at 12 spatial locations with 12 simultaneous background measurements at corresponding locations. The estimated signal at the machine-side collection optics is ~3.5 × 10(4) photons for plasma densities of 10(19) m(-3). Typical plasmas measured will range from densities of mid-10(18) to mid-10(19) m(-3) with electron temperatures from 10 to 1000 eV.

  17. Ultraviolet Thomson Scattering from Direct-Drive Coronal Plasmas

    NASA Astrophysics Data System (ADS)

    Henchen, R. J.; Goncharov, V. N.; Michel, D. T.; Follett, R. K.; Katz, J.; Froula, D. H.

    2013-10-01

    Ultraviolet (λ4 ω = 263 nm) Thomson scattering (TS) was used to probe ion-acoustic waves (IAW's) and electron plasma waves (EPW's) from direct-drive coronal plasmas. Fifty-nine drive beams (λ3 ω = 351 nm) illuminate a spherical target with a radius of ~860 μm. Advances in the ultraviolet (UV) TS diagnostic at the Omega Laser Facility provide the ability to detect deep UV photons (~190 nm) and allow access to scattered light from EPW's propagating near the 3 ω quarter-critical surface (~2.5 × 1021 cm-3) . A series of experiments studied the effects of ablator materials on coronal plasma conditions. Electron temperatures and densities were measured from 150 μm to 400 μm from the initial target surface. Standard CH shells were compared to three-layered shells consisting of Si doped CH, Si, and Be. Early analysis indicates that these multilayered targets have less hot-electron energy as a result of higher electron temperature in the coronal plasma. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  18. Electron-ion collision-frequency for x-ray Thomson scattering in dense plasmas

    SciTech Connect

    Faussurier, Gérald Blancard, Christophe

    2016-01-15

    Two methods are presented to calculate the electron-ion collision-frequency in dense plasmas using an average-atom model. The first one is based on the Kubo-Greenwood approach. The second one uses the Born and Lenard-Balescu approximations. The two methods are used to calculate x-ray Thomson scattering spectra. Illustrations are shown for dense beryllium and aluminum plasmas. Comparisons with experiment are presented in the case of an x-ray Thomson scattering spectrum.

  19. Electron-ion collision-frequency for x-ray Thomson scattering in dense plasmas

    NASA Astrophysics Data System (ADS)

    Faussurier, Gérald; Blancard, Christophe

    2016-01-01

    Two methods are presented to calculate the electron-ion collision-frequency in dense plasmas using an average-atom model. The first one is based on the Kubo-Greenwood approach. The second one uses the Born and Lenard-Balescu approximations. The two methods are used to calculate x-ray Thomson scattering spectra. Illustrations are shown for dense beryllium and aluminum plasmas. Comparisons with experiment are presented in the case of an x-ray Thomson scattering spectrum.

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

    SciTech Connect

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

    2006-09-01

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

  1. X-Ray Thomson Scattering Without the Chihara Decomposition

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  3. Chevron beam dump for ITER edge Thomson scattering system

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  4. Photon counting spectroscopy as done with a Thomson scattering diagnostic

    SciTech Connect

    Den Hartog, D.J.; Ruppert, D.E.

    1993-11-01

    The measurement and reduction of photon counting spectral data is demonstrated within the context of a Thomson scattering diagnostic. This diagnostic contains a microchannel plate (MCP) photomultiplier tube (PMT) as the photon sensing device. The MCP PMT is not an ideal photon sensor, the loss of photoelectrons at the MCP input and the broad charge pulse distribution at the output add to the uncertainty in recorded data. Computer simulations are used to demonstrate an approach to quantification of this added uncertainty and to develop an understanding of its source; the methodology may be applicable to the development of an understanding of photon detectors other than an MCP PMT. Emphasis is placed on the Poisson statistical character of the data, because the assumption that a Gaussian probability distribution is a reasonable statistical description of photon counting data is often questionable. When the count rate is low, the product the possible number of photon counts and the probability of measurement of a single photon is usually not sufficiently large to justify Gaussian statistics. Rather, because probabilities of measurement are so low, the Poisson probability distribution best quantifies the inherent statistical fluctuations in such counting measurements. The method of maximum likelihood is applied to derive the Poisson statistics equivalent of {sub X}{sup 2}. A Poisson statistics based data fitting code is implemented using the Newton-Raphson method of multi-dimensional root finding; we also demonstrate an algorithm to estimate the uncertainties in derived quantities.

  5. Relativistic nonlinear Thomson scattering as attosecond x-ray source.

    PubMed

    Lee, K; Cha, Y H; Shin, M S; Kim, B H; Kim, D

    2003-02-01

    Relativistic, nonlinear Thomson scattering by an electron of an intense laser field has been investigated by computer simulation. Under a laser field with a pulse duration of 20-fs full width at half maximum and an intensity of 10(20) W/cm(2), the motion of an electron is highly relativistic and generates an ultrashort radiation of 2 as with photon energies from 100 to 600 eV. An interesting modulated structure of the spectrum is observed and analyzed. A radiation produced by the zigzag motion of an electron under a linearly polarized laser has better characteristics than by a helical motion under a circularly polarized laser pulse in terms of an angular divergence and an energy spectrum. The effect of ion field in a plasma was also investigated, which shows that for a laser intensity of 10(20) W/cm(2), the ion field due to an ion density of up to 7 x 10(18) cm(-3) can be ignored during the laser pulse.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  7. Single-Pulse Multi-Point Multi-Component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  8. High sensitivity imaging Thomson scattering for low temperature plasma

    SciTech Connect

    Meiden, H. J. van der; Al, R. S.; Barth, C. J.; Donne, A. J. H.; Goedheer, W. J.; Groot, B. de; Koppers, W. R.; Pol, M. J. van de; Prins, P. R.; Shumack, A. E.; Smeets, P. H. M.; Vijvers, W. A. J.; Westerhout, J.; Wright, G. M.; Rooij, G. J. van; Engeln, R.; Kleyn, A. W.; Lopes Cardozo, N. J.; Schram, D. C.

    2008-01-15

    A highly sensitive imaging Thomson scattering system was developed for low temperature (0.1-10 eV) plasma applications at the Pilot-PSI linear plasma generator. The essential parts of the diagnostic are a neodymium doped yttrium aluminum garnet laser operating at the second harmonic (532 nm), a laser beam line with a unique stray light suppression system and a detection branch consisting of a Littrow spectrometer equipped with an efficient detector based on a ''Generation III'' image intensifier combined with an intensified charged coupled device camera. The system is capable of measuring electron density and temperature profiles of a plasma column of 30 mm in diameter with a spatial resolution of 0.6 mm and an observational error of 3% in the electron density (n{sub e}) and 6% in the electron temperature (T{sub e}) at n{sub e}=4x10{sup 19} m{sup -3}. This is achievable at an accumulated laser input energy of 11 J (from 30 laser pulses at 10 Hz repetition frequency). The stray light contribution is below 9x10{sup 17} m{sup -3} in electron density equivalents by the application of a unique stray light suppression system. The amount of laser energy that is required for a n{sub e} and T{sub e} measurement is 7x10{sup 20}/n{sub e} J, which means that single shot measurements are possible for n{sub e}>2x10{sup 21} m{sup -3}.

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

    SciTech Connect

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

    1994-02-01

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

  10. Scattering volume in the collective Thomson scattering measurement using high power gyrotron in the LHD

    NASA Astrophysics Data System (ADS)

    Kubo, S.; Nishiura, M.; Tanaka, K.; Moseev, D.; Ogasawara, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Tsujimura, T. I.; Makino, R.

    2016-06-01

    High-power gyrotrons prepared for the electron cyclotron heating at 77 GHz has been used for a collective Thomson scattering (CTS) study in LHD. Due to the difficulty in removing fundamental and/or second harmonic resonance in the viewing line of sight, the subtraction of the background ECE from measured signal was performed by modulating the probe beam power from a gyrotron. The separation of the scattering component from the background has been performed successfully taking into account the response time difference between both high-energy and bulk components. The other separation was attempted by fast scanning the viewing beam across the probing beam. It is found that the intensity of the scattered spectrum corresponding to the bulk and high energy components were almost proportional to the calculated scattering volume in the relatively low density region, while appreciable background scattered component remains even in the off volume in some high density cases. The ray-trace code TRAVIS is used to estimate the change in the scattering volume due to probing and receiving beam deflection effect.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

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

    2014-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    SciTech Connect

    Xie, M.

    1995-12-31

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

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

    SciTech Connect

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

    2016-01-01

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

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

    SciTech Connect

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

    2014-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    PubMed

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Nielsen, S. K.; Michelsen, P. K.; Hansen, S. K.; Korsholm, S. B.; Leipold, F.; Rasmussen, J.; Salewski, M.; Schubert, M.; Stejner, M.; Stober, J.; Wagner, D.; The ASDEX Upgrade Team

    2017-02-01

    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 respect to ion measurements are demonstrated. Examples include measurements of the ion temperature, energetic ion distribution function, and the ion composition.

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

    SciTech Connect

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

    2009-07-15

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

  1. Fast ion dynamics measured by collective Thomson scattering

    NASA Astrophysics Data System (ADS)

    Bindslev, Henrik

    2001-10-01

    In magnetically confined fusion plasmas, fast ions, from fusion reactions and auxiliary heating, typically carry a third of the total plasma kinetic energy, and even more of the free energy. This free energy must be channelled into heating the bulk plasma, but is also available for driving waves in the plasma, affecting confinement of bulk and fast ions. We know that fast ions can drive Alfvén waves, affect sawteeth and fishbones. In turn all three can redistribute or ejects the fast ions. Wave particle interaction, also the basis of Ion Cyclotron Resonance Heating (ICRH), depends crucially on the phase space distribution of the fast ions. Conversely the effect waves and instabilities have of fast ions will manifest itself in the detail of the fast ion phase space distribution. To explore the dynamics of fast ions and their interaction with the plasma thus begs for measurements of the fast ion distribution resolved in space, time and velocity. This has long been the promise of Collective Thomson Scattering (CTS) [1]. First demonstrated at JET [2]and subsequently at TEXTOR [3], CTS is living up to its promise and is now contributing to the understanding of fast ion dynamics. With the TEXTOR CTS, temporal behaviours of fast ion velocity distributions have been uncovered. The fast ion populations are produced by ICRH and Neutral Beam Injection (NBI). At sawteeth, we see clear variations in the fast ion population, which depend on ion energy, pitch angle and spatial location. Investigating the region just inside the inversion radius, we find that ions with small parallel energy, and with perpendicular energies up to a soft threshold well above thermal, are lost from the high field side near the inversion radius, while more energetic ions in the same pitch angle range remain insensitive to the sawteeth. The sensitive population could include the potato and stagnation orbit particles identified theoretically as being sensitive the sawteeth [4]. Under the same conditions

  2. Ultraviolet Thomson Scattering from Two-Plasmon-Decay Electron Plasma Waves Driven by Multiple Laser Beams

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    Thomson scattering is used to probe electron plasma waves (EPW's) driven by the common-wave two-plasmon-decay (TPD) instability near the quarter-critical density. Between two and five laser beams (λ3 ω = 351 nm) illuminated planar CH targets with 300- μm-diam (FWHM) laser spots with overlapped intensities ~1015 W/cm2. A 263-nm Thomson-scattering beam was used to probe densities ranging from 0.2 to 0.25 nc while k matching the TPD common wave. The Thomson-scattering spectra show two spectral peaks consistent with scattering from forward-scattered TPD common-wave EPW's and Langmuir decay of backscattered TPD waves. Broad TPD driven spectral features were observed in an alternate scattering configuration probing EPW k vectors that do not lie along a TPD maximum-growth hyperbola, consistent with TPD k-space saturation. Experimental results are compared to ZAK3D simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

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

    PubMed

    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.

  4. Improving measurement accuracy by optimum data acquisition for Nd:YAG Thomson scattering system.

    PubMed

    Minami, T; Itoh, Y; Yamada, I; Yasuhara, R; Funaba, H; Nakanishi, H; Hatae, T

    2014-11-01

    A new high speed Nd:YAG Thomson scattering AD Convertor (HYADC) that can directly convert the detected scattered light signal into a digital signal is under development. The HYADC is expected to improve a signal to noise ratio of the Nd:YAG Thomson scattering measurement. The data storage of the HYADC which is required for the direct conversion of whole plasma discharge is drastically reduced by a ring buffer memory and a stop trigger system. Data transfer of the HYADC is performed by the SiTCP. The HYADC is easily expandable to a multi-channel system by the distributed data processing, and is very compact and easy to implement as a built-in system of the polychromators.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

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

  7. Scattering of strong electromagnetic wave by relativistic electrons: Thomson and Compton regimes

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

    The processes of the nonlinear Compton and the nonlinear Thomson scattering in a field of intense plane electromagnetic wave in terms of photon yield have been considered. The quantum consideration of the Compton scattering process allows us to calculate the probability of a few successive collisions k of an electron with laser photons accompanied by the absorption of n photons (nonlinear regime) when the number of collisions and the number of absorbed photons are of random quantities. The photon spectrum of the nonlinear Thomson scattering process was obtained from the classical formula for intensity using the Planck's law. The conditions for which the difference between the classical and the quantum regimes is manifested was obtained. Such a condition is determined by a discrete quantum radiation mechanism, namely, by the mean number of photons k bar emitted by an electron passing through the laser pulse.

  8. Electron kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited)a)

    NASA Astrophysics Data System (ADS)

    Mirnov, V. V.; Brower, D. L.; Hartog, D. J. Den; Ding, W. X.; Duff, J.; Parke, E.

    2014-11-01

    At anticipated high electron temperatures in ITER, the effects of electron thermal motion on Thomson scattering (TS), toroidal interferometer/polarimeter (TIP), and poloidal polarimeter (PoPola) diagnostics will be significant and must be accurately treated. The precision of the previous lowest order linear in τ = Te/mec2 model may be insufficient; we present a more precise model with τ2-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. The linear model is extended from Maxwellian to a more general class of anisotropic electron distributions that allows us to take into account distortions caused by equilibrium current, ECRH, and RF current drive effects. The classical problem of the degree of polarization of incoherent Thomson scattered radiation is solved analytically exactly without any approximations for the full range of incident polarizations, scattering angles, and electron thermal motion from non-relativistic to ultra-relativistic. The results are discussed in the context of the possible use of the polarization properties of Thomson scattered light as a method of Te measurement relevant to ITER operational scenarios.

  9. Bayesian modelling of JET high resolution Thomson scattering system using the Minerva framework

    NASA Astrophysics Data System (ADS)

    Kwak, Sehyun; Svensson, Jakob; Bozhenkov, Sergey; Flanagan, Joanne; Kempenaars, Mark; Ghim, Young-Chul; JET Contributors Collaboration

    2016-10-01

    A Bayesian model for JET high resolution Thomson scattering (HRTS) system has been developed to infer electron temperature and density profiles. The model has been implemented in the Minerva framework. The HRTS system detects Thomson scattered photons from the injected 20 ns long laser pulse penetrating along the midplane of the JET at 63 spatial points on the low field side (R = 2.9 3.9 m) with 1 1.6 cm spatial resolution and 20 Hz repetition rate. The Selden-Matoba Thomson scattering model infers scattered and stray light intensities as well as associated uncertainties taking into account of photon statistics and electrical fluctuations. The Markov Chain Monte Carlo (MCMC) method explores the posterior distribution of the electron temperature and density profiles which explain both HRTS and the interferometry data simultaneously within their uncertainties. The electron temperature and density profiles are modelled via Gaussian processes mapped onto normalised flux coordinates. The electron density profiles are automatically calibrated through the inclusion of interferometers in the model.

  10. Central Thomson Scattering Diagnostic for DIII--D

    NASA Astrophysics Data System (ADS)

    Bray, B.; Carlstrom, T. N.; Hsieh, C.; Marakiou, C. C.; Nilson, D.

    1998-11-01

    The Thomson diagnostic on DIII--D has eight YAG lasers operating at 20 Hz each and two vertical beam paths covering most of the plasma including the boundary and divertor regions. In certain instances such as high performance discharges with an internal transport barrier, the measurement can miss the plasma center by about 10--20 cm. In order to cover this central region of increasing importance, we plan to install a horizontal beam path with up to 3 lasers diverted from the existing system, a laser dump inside the machine vessel, and a maximum of 12 viewing channels. Most system hardware including lasers and polychromators will be made sharable so the spatial and temporal resolution can be arranged according to the requirements of a specific experiment. Upgrades are also planned for control and data analysis to replace older computer hardware and software. This new software will have more inspection functions to maintain the quality of the data and provide the flexibility that the plasma experiment requires. The plans for the expansion and progress will be presented.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    PubMed

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

    2016-11-01

    Neural networks provide powerful approaches of dealing with nonlinear data and have been successfully applied to fusion plasma diagnostics and control systems. Controlling tokamak plasmas in real time is essential to measure the plasma parameters in situ. However, the χ(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(2) method. The best results were obtained for 10(3) training cycles and eight nodes in the hidden layer. Our neural network approach shows good agreement with the χ(2) method and performs the calculation twenty times faster.

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

    SciTech Connect

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

    2007-06-07

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

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

    PubMed

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

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  16. Modular Python-based Code for Thomson Scattering System on NSTX-U

    NASA Astrophysics Data System (ADS)

    Horowitz, Benjamin; Diallo, Ahmed; Feibush, Eliot; Leblanc, Benoit

    2013-10-01

    Fast accurate and reliable measurements of electron temperature and density profiles within magnetically confined plasmas are essential for full operation of fusion devices. We detail the design and implementation of a modular Pythonbased code for the Thomson Scattering diagnostic system of NSTX-U which offers improvements in speed by making full use of the Python's architecture, open-source module packages, and ability to be parallelized across many processors. SciPy's weave package allows the implementation of C/C++ code within our program to clear up bottlenecks in data fitting while not loosing the flexibility and clarity of Python, while Numpy and MatplotLib allow calculations and plotting of the processed data. Using the standard MDSplus input, we create a flexible and expandable algorithm structure which can be implemented on any fusion device utilizing polychromator-based Thomson scattering diagnostic system. Supported by DOE SULI Fellowship at Princeton Plasma Physics Lab.

  17. Observation of the second harmonic in Thomson scattering from relativistic electrons.

    PubMed

    Babzien, Marcus; Ben-Zvi, Ilan; Kusche, Karl; Pavlishin, Igor V; Pogorelsky, Igor V; Siddons, David P; Yakimenko, Vitaly; Cline, David; Zhou, Feng; Hirose, Tachishige; Kamiya, Yoshio; Kumita, Tetsuro; Omori, Tsunehiko; Urakawa, Junji; Yokoya, Kaoru

    2006-02-10

    A free relativistic electron in an electromagnetic field is a pure case of a light-matter interaction. In the laboratory environment, this interaction can be realized by colliding laser pulses with electron beams produced from particle accelerators. The process of single photon absorption and reemission by the electron, so-called linear Thomson scattering, results in radiation that is Doppler shifted into the x-ray and gamma-ray regions. At elevated laser intensity, nonlinear effects should come into play when the transverse motion of the electrons induced by the laser beam is relativistic. In the present experiment, we achieved this condition and characterized the second harmonic of Thomson x-ray scattering using the counterpropagation of a 60 MeV electron beam and a subterawatt CO2 laser beam.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  19. Observation of the Second Harmonic in Thomson Scattering from Relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Babzien, Marcus; Ben-Zvi, Ilan; Kusche, Karl; Pavlishin, Igor V.; Pogorelsky, Igor V.; Siddons, David P.; Yakimenko, Vitaly; Cline, David; Zhou, Feng; Hirose, Tachishige; Kamiya, Yoshio; Kumita, Tetsuro; Omori, Tsunehiko; Urakawa, Junji; Yokoya, Kaoru

    2006-02-01

    A free relativistic electron in an electromagnetic field is a pure case of a light-matter interaction. In the laboratory environment, this interaction can be realized by colliding laser pulses with electron beams produced from particle accelerators. The process of single photon absorption and reemission by the electron, so-called linear Thomson scattering, results in radiation that is Doppler shifted into the x-ray and γ-ray regions. At elevated laser intensity, nonlinear effects should come into play when the transverse motion of the electrons induced by the laser beam is relativistic. In the present experiment, we achieved this condition and characterized the second harmonic of Thomson x-ray scattering using the counterpropagation of a 60 MeV electron beam and a subterawatt CO2 laser beam.

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

    NASA Technical Reports Server (NTRS)

    Praddaude, H. C.; Woskoboinikow, P.

    1978-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  2. Laser Thomson scattering measurements of electron temperature and density in a hall-effect plasma

    NASA Astrophysics Data System (ADS)

    Washeleski, Robert L.

    Hall-effect thrusters (HETs) are compact electric propulsion devices with high specific impulse used for a variety of space propulsion applications. HET technology is well developed but the electron properties in the discharge are not completely understood, mainly due to the difficulty involved in performing accurate measurements in the discharge. Measurements of electron temperature and density have been performed using electrostatic probes, but presence of the probes can significantly disrupt thruster operation, and thus alter the electron temperature and density. While fast-probe studies have expanded understanding of HET discharges, a non-invasive method of measuring the electron temperature and density in the plasma is highly desirable. An alternative to electrostatic probes is a non-perturbing laser diagnostic technique that measures Thomson scattering from the plasma. Thomson scattering is the process by which photons are elastically scattered from the free electrons in a plasma. Since the electrons have thermal energy their motion causes a Doppler shift in the scattered photons that is proportional to their velocity. Like electrostatic probes, laser Thomson scattering (LTS) can be used to determine the temperature and density of free electrons in the plasma. Since Thomson scattering measures the electron velocity distribution function directly no assumptions of the plasma conditions are required, allowing accurate measurements in anisotropic and non-Maxwellian plasmas. LTS requires a complicated measurement apparatus, but has the potential to provide accurate, non-perturbing measurements of electron temperature and density in HET discharges. In order to assess the feasibility of LTS diagnostics on HETs non-invasive measurements of electron temperature and density in the near-field plume of a Hall thruster were performed using a custom built laser Thomson scattering diagnostic. Laser measurements were processed using a maximum likelihood estimation method

  3. 21nm x-ray laser Thomson scattering of laser-heated exploding foil plasmas

    SciTech Connect

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

    2007-09-26

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

  4. Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak

    SciTech Connect

    Kurzan, B.; Murmann, H. D.

    2011-10-15

    A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator.

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

    SciTech Connect

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

    2013-09-15

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

  6. Design of an Optical Thomson Scattering diagnostic at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Galbraith, Justin; Datte, Phil; Ross, Steven; Swadling, George; Manuel, Stacie; Molander, Bill; Hatch, Ben; Manha, Dan; Vitalich, Mike; Petre, Brad

    2016-09-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Inertial Confinement Fusion program based on laser-target interactions. The Optical Thomson Scattering (OTS) diagnostic 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. A deep-UV probe beam is needed to overcome the large background of self-Thomson scattering produced by the 351nm (3ω) NIF drive beams. A two-phase approach to OTS on NIF will mitigate the risk presented by background levels. In Phase I, the diagnostic will assess background levels around a potential deep-UV probe wavelength considered for 5ω Thomson scattering measurements to be conducted in Phase II. The Phase I design of the diagnostic includes an unobscured collection telescope, dual crossed Czerny-Turner spectrometers, and the shared use of one streak camera located inside of an airbox. The Phase II design will include a 5ω probe laser. We will describe the engineering design and concept of operations of the Phase I NIF OTS diagnostic, with a focus on optomechanical disciplines.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  8. Z-pinch Plasma Temperature and Implosion Velocity from Laboratory Plasma Jets using Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Banasek, Jacob; Byvank, Tom; Kusse, Bruce; Hammer, David

    2016-10-01

    We discuss the use of collective Thomson scattering to determine the implosion velocity and other properties of laboratory plasma jets. The plasma jet is created using a 1 MA pulsed power machine with a 15 μm Al radial foil load. The Thomson scattering laser has a maximum energy of 10 J at 526.5 nm with a pulse duration of 3 ns. Using a time gated ICCD camera and spectrometer system we are able to record the scattered spectrum from 9 or 18 regions along the laser path with sub-mm spatial resolution. Collecting scattered radiation from the same area at two different angles simultaneously enables determination of both the radial and azimuthal velocities. The scattered spectrum for non-magnetized jets indicates a radial implosion velocity of 27 km/s into the jets. A determination of ion and electron temperatures from the scattered spectrum is in progress. Comparing results using a laser energy of 10 J and 1 J shows noticeable effects on plasma jet properties when using 10 J. Therefore the lower laser energy must be used to determine the plasma properties. This research is supported by the NNSA Stewardship Sciences Academic Programs under DOE Cooperative Agreement DE-NA0001836.

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

    SciTech Connect

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

    2009-05-07

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

  10. LIGHT SOURCE: TW Laser system for Thomson scattering X-ray light source at Tsinghua University

    NASA Astrophysics Data System (ADS)

    Yan, Li-Xm; Du, Ying-Chao; Du, Qiang; Li, Ren-Kai; Hua, Jian-Fei; Huang, Wen-Hui; Tang, Chuan-Xiang

    2009-06-01

    A TW (Tera Watt) laser system based on Ti:sapphire mainly for the Tsinghua Thomson scattering X-ray light source (TTX) is being built. Both UV (ultraviolet) laser pulse for driving the photocathode radio-frequency (RF) gun and the IR (infrared) laser pulse as the electron-beam-scattered-light are provided by the system. Efforts have also been made in laser pulse shaping and laser beam transport to optimize the high-brightness electron beam production by the photocathode RF gun.

  11. Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration

    SciTech Connect

    Xu, Tong; Chen, Min Li, Fei-Yu; Yu, Lu-Le; Sheng, Zheng-Ming; Zhang, Jie

    2014-01-06

    We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

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

    SciTech Connect

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

    2006-11-21

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

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

    SciTech Connect

    McLean, H; Moller, J; Hill, D

    2004-04-19

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

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

    DOE PAGES

    Fletcher, L. B.; Glenzer, S. H.; Kritcher, A.; ...

    2013-05-24

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

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

    SciTech Connect

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

    2013-05-24

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

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

    SciTech Connect

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

    2013-05-15

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

  17. Polarization of x-gamma radiation produced by a Thomson and Compton inverse scattering

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Drebot, I.; Giribono, A.; Maroli, C.; Rossi, A. R.; Serafini, L.; Tomassini, P.; Vaccarezza, C.; Variola, A.

    2015-11-01

    A systematic study of the polarization of x-gamma rays produced in Thomson and Compton scattering is presented, in both classical and quantum schemes. Numerical results and analytical considerations let us to establish the polarization level as a function of acceptance, bandwidth and energy. Few sources have been considered: the SPARC_LAB Thomson device, as an example of a x-ray Thomson source, ELI-NP, operating in the gamma range. Then, the typical parameters of a beam produced by a plasma accelerator has been analyzed. In the first case, with bandwidths up to 10%, a contained reduction (<10 % ) in the average polarization occurs. In the last case, for the nominal ELI-NP relative bandwidth of 5 ×1 0-3 , the polarization is always close to 1. For applications requiring larger bandwidth, however, a degradation of the polarization up to 30% must be taken into account. In addition, an all optical gamma source based on a plasma accelerated electron beam cannot guarantee narrow bandwidth and high polarization operational conditions required in nuclear photonics experiments.

  18. Classical Heat-Flux Measurements in Coronal Plasmas from Collective Thomson-Scattering Spectra

    NASA Astrophysics Data System (ADS)

    Henchen, R. J.; Hu, S. X.; Katz, J.; Froula, D. H.; Rozmus, W.

    2016-10-01

    Collective Thomson scattering was used to measure heat flux in coronal plasmas. The relative amplitude of the Thomson-scattered power into the up- and downshifted electron plasma wave features was used to determine the flux of electrons moving along the temperature gradient at three to four times the electron thermal velocity. Simultaneously, the ion-acoustic wave features were measured. Their relative amplitude was used to measure the flux of the return-current electrons. The frequencies of these ion-acoustic and electron plasma wave features provide local measurements of the electron temperature and density. These spectra were obtained at five locations along the temperature gradient in a laser-produced blowoff plasma. These measurements of plasma parameters are used to infer the Spitzer-Härm flux (qSH = - κ∇Te ) and are in good agreement with the values of the heat flux measured from the scattering-feature asymmetries. Additional experiments probed plasma waves perpendicular to the temperature gradient. The data show small effects resulting from heat flux compared to probing waves along the temperature gradient. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  1. Femtosecond x-rays from Thomson scattering using laser wakefield accelerators

    SciTech Connect

    Catravas, P.; Esarey, E.; Leemans, W.P.

    2001-03-01

    The possibility of producing femtosecond x-rays through Thomson scattering high power laser beams off laser wakefield generated relativistic electron beams is discussed. The electron beams are produced with either a self-modulated laser wakefield accelerator (SM-LWFA) or through a standard laser wakefield accelerator (LWFA) with optical injection. For a SM-LWFA (LWFA) produced electron beam, a broad (narrow) energy distribution is assumed, resulting in X-ray spectra that are broadband (monochromatic). Designs are presented for 3-100 fs x-ray pulses and the expected flux and brightness of these sources are compared.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2015-02-01

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

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

    SciTech Connect

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

    2013-07-28

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

  5. Thomson scattering measurement of a shock in laser-produced counter-streaming plasmas

    SciTech Connect

    Morita, T.; Kuramitsu, Y.; Moritaka, T.; Sakawa, Y.; Takabe, H.; Tomita, K.; Nakayama, K.; Inoue, K.; Uchino, K.; Ide, T.; Tsubouchi, K.; Nishio, K.; Ide, H.; Kuwada, M.

    2013-09-15

    We report the first direct measurement of temporally and spatially resolved plasma temperatures at a shock as well as its spatial structure and propagation in laser-produced counter-streaming plasmas. Two shocks are formed in counter-streaming collisionless plasmas early in time, and they propagate opposite directions. This indicates the existence of counter-streaming collisionless flows to keep exciting the shocks, even though the collisional effects increase later in time. The shock images are observed with optical diagnostics, and the upstream and downstream plasma parameters of one of the shocks are measured using Thomson scattering technique.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  7. Measurement of electron temperature and density in an argon microdischarge by laser Thomson scattering

    NASA Astrophysics Data System (ADS)

    Belostotskiy, Sergey G.; Khandelwal, Rahul; Wang, Qiang; Donnelly, Vincent M.; Economou, Demetre J.; Sadeghi, Nader

    2008-06-01

    Laser Thomson scattering in a novel, backscattered configuration was employed to measure the electron temperature (Te) and electron density (ne) in argon dc microdischarges, with an interelectrode gap of 600μm. Measurements were performed at the center of the gap that corresponds to the positive column. For 50mA microdischarge current and over the pressure range of 300-700Torr, the plasma parameters were found to be Te=0.9±0.3eV and ne=(6±3)×1013cm-3, in reasonable agreement with the predictions of a mathematical model.

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

    SciTech Connect

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

    1997-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

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

    PubMed

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

    2016-11-01

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

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

    PubMed

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

    2014-11-01

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

  12. Data processing and analysis of the imaging Thomson scattering diagnostic system on HT-7 tokamak.

    PubMed

    Han, Xiaofeng; Shao, Chunqiang; Xi, Xiaoqi; Zhao, Junyu; Qing, Zang; Yang, Jianhua; Dai, Xingxing; Kado, Shinichiro

    2013-05-01

    A high spatial resolution imaging Thomson scattering diagnostic system was developed in ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences). After about one month trial running on the superconducting HT-7 (Hefei Tokamak-7) tokamak, the system was proved to be capable of measuring plasma electron temperature. The system setup and data calibration are described in this paper and then the instrument function is studied in detail, as well as the measurement capability, an electron temperature of 50 eV to 2 keV and density beyond 1 × 10(19) m(-3). Finally, the data processing method and experimental results are presented.

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

    SciTech Connect

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

    1997-07-08

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  15. High-Repetition-Rate Laser for Thomson Scattering on the MST Reversed-Field Pinch

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    The MST Thomson scattering diagnostic has operated with a new, high-repetition-rate laser system, demonstrating 2 J pulses at repetition rates up to 50 kHz. The pulse repetition rate can maintain 2 J pulses for bursts of 5 kHz (sustained for 5 ms), to 50 kHz (for 10 bursts of 240 μs each). The 1064 nm laser currently employs a q-switched, diode pumped Nd:YVO4 master oscillator, four Nd:YAG amplifier stages, and a Nd:glass amplifier. The future implementation of the full laser as designed, including a second Nd:glass amplifier, is expected to produce bursts of 2 J pulses at a repetition rate of at least 250 kHz. The new laser integrates with the same collection optics and detectors as used by the present MST Thomson scattering system: 21 spatial points across the MST minor radius with sensitivity over a 10 eV-5 keV range. Initial results will be presented from application of this diagnostic to parametric scans of MST plasmas, evolution of energy confinement during spontaneous enhanced confinement periods, and non-Maxwellian electron distributions. Work Supported by the U. S. Department of Energy and National Science Foundation.

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

    SciTech Connect

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

    2005-09-26

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

  17. Prospects for measuring shifted- and non-Maxwellian electron distributions with Thomson scattering on MST

    NASA Astrophysics Data System (ADS)

    Kubala, S. Z.; den Hartog, D. J.; Dubois, A. M.; Morton, L. A.; Young, W. C.

    2016-10-01

    Recent measurements using a high-time-resolution soft x-ray spectrometer on MST suggest that a non-Maxwellian, energetic electron tail is generated during magnetic reconnection events. This has motivated the addition to the Thomson scattering (TS) diagnostic of the capability to measure shifted- and non-Maxwellian distribution functions. To that end, an 1140 nm centerline filter with 80 nm bandwidth has been installed in nine of 21 polychromators. This filter supplements a filter set that covers from approximately 715 nm to 1065 nm, used to measure Thomson scattered light from the 1064 nm YAG laser line. Simulations being performed will assess whether the TS diagnostic with the upgraded filter set will be capable of detecting a small population (around 5% of the electron density) of energetic electrons, and whether an eight-channel polychromator, which has increased resolution but also is inherently more noisy, provides a better fit than a six-channel polychromator. This work is supported by the U.S. DOE and NSF.

  18. X-ray Thomson scattering measurement of temperature in warm dense carbon

    NASA Astrophysics Data System (ADS)

    Falk, K.; Fryer, C. L.; Gamboa, E. J.; Greeff, C. W.; Johns, H. M.; Schmidt, D. W.; Šmíd, M.; Benage, J. F.; Montgomery, D. S.

    2017-01-01

    A novel platform to measure the equation of state using a combination of diagnostics, where the spectrally resolved x-ray Thomson scattering (XRTS) is used to obtain accurate temperature measurements of warm dense matter (WDM) was developed for the OMEGA laser facility. OMEGA laser beams have been used to drive strong shocks in carbon targets creating WDM and generating the Ni He-alpha x-ray probe used for XRTS. Additional diagnostics including x-ray radiography, velocity interferometry and streaked optical pyrometry provided complementary measurements of density and pressure. The WDM regime of near solid density and moderate temperatures (1-100 eV) is a challenging yet important area of research in inertial confinement fusion and astrophysics. This platform has been used to study off-Hugoniot states of shock-released diamond and graphite at pressures between 1 and 10 Mbar and temperatures between 5 and 15 eV as well as first x-ray Thomson scattering data from shocked low density CH foams reaching five times compression and temperatures of 20-30 eV.

  19. Detecting non-Maxwellian electron velocity distributions at JET by high resolution Thomson scattering

    SciTech Connect

    Beausang, K. V.; Prunty, S. L.; Scannell, R.; Beurskens, M. N.; Walsh, M. J.; Collaboration: JET EFDA Contributors

    2011-03-15

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

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

    PubMed

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

    2011-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

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

    SciTech Connect

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

    2014-09-15

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

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

    SciTech Connect

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

    2010-10-15

    Neutron and gamma-ray irradiation complicates the design of the edge Thomson scattering (TS) system in ITER. The TS light is relayed through the relaying optics with labyrinth and fiber coupling optics. Electron density of 2x10{sup 19} m{sup -3} is sufficient to measure T{sub e} and n{sub e} within a 10% and 5% margin of error, respectively, with a spatial resolution of 5 mm. This system can cover from 0.85 to 1 of the normalized minor radius. The time resolution is 10 ms, which is determined by the repetition rate of the laser device. A super-Gaussian is the ideal laser profile for the laser injection optics to avoid a breakdown of the filling gas used in density calibration through Raman scattering.

  5. Conceptual design of the collection optics for the edge Thomson scattering system in ITERa)

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    Neutron and gamma-ray irradiation complicates the design of the edge Thomson scattering (TS) system in ITER. The TS light is relayed through the relaying optics with labyrinth and fiber coupling optics. Electron density of 2×1019 m-3 is sufficient to measure Te and ne within a 10% and 5% margin of error, respectively, with a spatial resolution of 5 mm. This system can cover from 0.85 to 1 of the normalized minor radius. The time resolution is 10 ms, which is determined by the repetition rate of the laser device. A super-Gaussian is the ideal laser profile for the laser injection optics to avoid a breakdown of the filling gas used in density calibration through Raman scattering.

  6. Investigation of X-Ray Thomson Scattering Using A Statistical Approach

    NASA Astrophysics Data System (ADS)

    Johnson, Laura

    2014-10-01

    We present a statistical method of computing x-ray Thomson scattering signals. This model uses average atom wave functions for both bound and continuum electrons, which are computed in a spherically symmetric, self-consistent potential. The wave functions are used to obtain electron distributions for a statistical approach to computing the scattering signals. We compare the differences between using distorted-wave continuum electrons and free-wave electrons in both the statistical approach and the impulse approximation. The results are compared to various experiments including experimental data taken at Cornell's Laboratory of Plasma Studies. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

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

    SciTech Connect

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

    1996-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  10. Dynamic Thomson Scattering from Nonlinear Electron Plasma Waves in a Raman Plasma Amplifier

    NASA Astrophysics Data System (ADS)

    Davies, A.; Katz, J.; Bucht, S.; Haberberger, D.; Bromage, J.; Zuegel, J. D.; Froula, D. H.; Trines, R.; Bingham, R.; Sadler, J.; Norreys, P. A.

    2016-10-01

    Electron plasma waves (EPW's) can be used to transfer significant energy from a long-pulse laser to a short-pulse seed laser through the Raman scattering instability. Successful implementation of Raman amplification could open an avenue to producing high-intensity pulses beyond the capabilities of current laser technology ( 1022 W / cm 2). This three-wave interaction takes advantage of the plasma's ability to sustain large-amplitude plasma waves. Having complete knowledge of the EPW amplitude is essential to establishing optimal parameters for high-efficiency Raman amplification. A dynamic Thomson-scattering diagnostic is being developed to spatially and temporally resolve the amplitude of the driven and thermal EPW's. By imaging the scattered probe light onto a novel pulse-front tilt compensated streaked optical spectrometer, the diffraction efficiency of this plasma wave can be measured as a function of space and time. These data will be used in conjunction with particle-in-cell simulations to determine the EPW's spatial and temporal profile. This will allow the effect of the EPW profile on Raman scattering to be experimentally determined. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

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

    PubMed

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

    2016-11-01

    The edge tangential Thomson scattering system (ETTSS) was developed for the first time on a HL-2A tokamak. A Nd:YAG laser with a 1064 nm wavelength, 4 J energy, and 30 Hz repetition rate is employed on the ETTSS. The laser beam injects the plasma in the tangential direction on the mid-plane of the machine, and the angles between the laser injection direction and the scattered light collection direction are in the range from 157.5° to 162.8°. The scattered light collection optics with 0.21-0.47 magnification is utilized to collect the scattered light of measurement range from R = 1900 mm to 2100 mm (the normalized radius is from r/a = 0.625 to 1.125). Spatial resolution of the preliminary design could be up to Δr/a = 0.016. The measurement requirements could be achieved: 10 eV < Te < 1.5 keV, and 0.5 × 10(19) m(-3) < ne < 3 × 10(19) m(-3) with errors less than 15% and 10%, respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  13. Pulse-burst laser systems for fast Thomson scattering (invited)a)

    NASA Astrophysics Data System (ADS)

    Den Hartog, D. J.; Ambuel, J. R.; Borchardt, M. T.; Falkowski, A. F.; Harris, W. S.; Holly, D. J.; Parke, E.; Reusch, J. A.; Robl, P. E.; Stephens, H. D.; Yang, Y. M.

    2010-10-01

    Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.

  14. Experimental Demonstration of Incoherent and Coherent Relativistic Thomson Scattering in Plasmas

    NASA Astrophysics Data System (ADS)

    Umstadter, Donald; Chen, Szu-Yuan; Maksimchuk, Anatoly

    2000-04-01

    Short-wavelength ultrashort-duration laser-produced light sources enable a marriage between observations on the ultra-fast with those on the ultra-small scales, giving scientists novel and exciting research capabilities. We discuss recent experimental results on relativistic Thomson scattering from free electrons in plasmas, which may lead to such a source. In this case, electrons radiate harmonics due to their highly nonlinear relativistic motion in the focus of an intense laser field (10^18 W/cm^2 for 1-μm light). Results on both incoherent and phase-matched harmonic generation by this novel mechanism are described. In the latter case, we report the observation of a five-degree cone of third-harmonic emission in the forward direction.

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

    SciTech Connect

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

    2014-05-15

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

  16. Subnanosecond Thomson scattering on a vacuum arc discharge in tin vapor.

    PubMed

    Kieft, E R; van der Mullen, J J A M; Banine, V

    2005-08-01

    In a previous series of Thomson scattering (TS) experiments on an extreme ultraviolet producing vacuum arc discharge in tin vapor, background radiation emitted by the plasma was found to make measurements impossible for all parts of the discharge except the prepinch phase. To reduce the level of recorded background radiation, we have built a setup for time and space resolved subnanosecond TS. Results obtained with this new setup are presented for experiments on previously inaccessible parts of the discharge--the ignition phase, pinch phase, and decay phase. For the first two, measurements have been performed at different heights in the plasma. Electron densities for the pinch phase have been derived. For the decay phase, the electron densities confirm previous Stark broadening data. From the overall results, a more complete picture of the plasma evolution can be formed.

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

    SciTech Connect

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

    2012-06-15

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

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

    SciTech Connect

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

    2015-02-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  20. Thomson Scattering and Spectroscopy Diagnostics for Low Frequency Turbulence Produced in Dual-wire Implosions

    NASA Astrophysics Data System (ADS)

    Plechaty, Christopher; Hamilton, Andy; Main, Daniel; Zechar, Nate; Sotnikov, Vladimir

    2015-11-01

    Low frequency plasma turbulence can be driven by the presence of inhomogeneity in density, temperature, magnetic field, or by velocity shear. Low Frequency instabilities can play an important role in many different types of processes, such as magnetic reconnection, plasma structuring in the ionosphere's F-layer, structuring of laser-produced plasmas in external magnetic field, and anomalous diffusion processes in theta-pinch and Z-pinch plasmas. We plan to carry out experiments at the Air Force Research Laboratory using a pulsed power generator to study two-wire implosions and the generation of the Lower-Hybrid Drift Instability in the vicinity of the reconnection region. In this work, we develop the Thomson scattering and visible spectroscopy diagnostics that will be ultimately used to characterize the plasma in these types of experiments. Work was performed under the auspices of the Air Force Research Laboratory by Riverside Research, under contract BAA-RQKS-2014-0009.

  1. Attosecond Thomson-scattering x-ray source driven by laser-based electron acceleration

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    The possibility of producing attosecond x-rays through Thomson scattering of laser light off laser-driven relativistic electron beams is investigated. For a ≤200-as, tens-MeV electron bunch produced with laser ponderomotive-force acceleration in a plasma wire, exceeding 106 photons/s in the form of ˜160 as pulses in the range of 3-300 keV are predicted, with a peak brightness of ≥5 × 1020 photons/(s mm2 mrad2 0.1% bandwidth). Our study suggests that the physical scheme discussed in this work can be used for an ultrafast (attosecond) x-ray source, which is the most beneficial for time-resolved atomic physics, dubbed "attosecond physics."

  2. Data-driven sensitivity inference for Thomson scattering electron density measurement systems

    NASA Astrophysics Data System (ADS)

    Fujii, Keisuke; Yamada, Ichihiro; Hasuo, Masahiro

    2017-01-01

    We developed a method to infer the calibration parameters of multichannel measurement systems, such as channel variations of sensitivity and noise amplitude, from experimental data. We regard such uncertainties of the calibration parameters as dependent noise. The statistical properties of the dependent noise and that of the latent functions were modeled and implemented in the Gaussian process kernel. Based on their statistical difference, both parameters were inferred from the data. We applied this method to the electron density measurement system by Thomson scattering for the Large Helical Device plasma, which is equipped with 141 spatial channels. Based on the 210 sets of experimental data, we evaluated the correction factor of the sensitivity and noise amplitude for each channel. The correction factor varies by ≈10%, and the random noise amplitude is ≈2%, i.e., the measurement accuracy increases by a factor of 5 after this sensitivity correction. The certainty improvement in the spatial derivative inference was demonstrated.

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

    PubMed

    Bohm, P; Sestak, D; Bilkova, P; Aftanas, M; Weinzettl, V; Hron, M; Panek, R; Baillon, L; Dunstan, M R; Naylor, G; Walsh, M J

    2010-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.

    2016-03-01

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

  6. X-ray Thomson scattering as a temperature probe for gigabar shock experiments

    NASA Astrophysics Data System (ADS)

    Doeppner, T.; Kritcher, A.; Glenzer, S.; Chapman, D.; Falcone, R.; Neumayer, P.

    2013-06-01

    In X-ray Thomson scattering (XRTS), high-resolution spectrometry of probe x-rays scattered from matter gives an elastic (ionic) and an inelastic (electronic) feature, whose location, width, and amplitude can be analyzed for the temperature and density of the electrons. This diagnostic is complementary to traditional, mechanical EOS measurements which do not directly constrain temperature. XRTS has been demonstrated on planar dynamic-loading experiments at the Omega laser, and a spectrometer has been constructed for use at the National Ignition Facility (NIF). We plan to obtain XRTS measurements into the gigabar regime using hohlraum-driven converging shocks at NIF. In these experiments, the radial profile through the sample at any instant of time varies greatly, though the XRTS signal is dominated by the hottest region, which is at the shock front where simultaneous radiography obtains an equation of state measurement. However, the shock signal is potentially obscured by scattering from the preheat shield, comprising a higher-Z dopant than the sample. Thus we are developing an imaging spectrometer, which should enable a spatial unfold of XRTS spectrum, providing a more precise temperature measurement at the shock front and potentially in the converging flow behind the shock. U.S. DOE contract DE-AC52-07NA27344.

  7. Improvements, upgrades, and plans for Thomson scattering on DIII-D

    NASA Astrophysics Data System (ADS)

    Carlstrom, T. N.; Du, D.; Glass, F.; Liu, C.; Watkins, M.; McLean, A. G.

    2016-10-01

    The Thomson scattering diagnostic on DIII-D consists of 3 beam lines that probe vertically, horizontally, and in the divertor region of the tokamak, with 54 spatial locations, edge spatial resolution down to 5 mm, and 10 Nd:YAG lasers. In its 25-year history, the collection lens optics and interference filters degraded and have been replaced, restoring previous performance. In addition, improved calibrations and detector temperature control (+/- 0.1 C) have reduced systematic errors. Cross calibration with the CO2 interferometer and ECE cut-off have improved the density calibration. Improvements to the beam line and lasers have increased the laser energy delivered to the scattering volume in the plasma. Future plans include moving the divertor system to measure regions of high triangularity using in-vessel mirrors to redirect the laser beam; adding a wide angle lens to the horizontal system to view the entire plasma radius near the plasma mid plane; and reversing the direction of the laser beam on the horizontal system to reduce the scattering angle and compressing the spectrum in wavelength space so that higher central Te measurements (<5 KeV) can be made with improved accuracy. Work supported by the US DOE under DE-FC02-04ER54698 and by LLNL under DE-AC52-07NA27344.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  10. Development of a Thomson scattering diagnostic for the Caltech jet-target experiment

    NASA Astrophysics Data System (ADS)

    Seo, Byong Hoon; Greig, Amelia; Bellan, Paul

    2016-10-01

    A Thomson scattering diagnostic is being developed for studying the Caltech jet-target impact experiment. This experiment has a high-speed MHD-driven jet impact a dense, high-mass target cloud. The compression of the jet upon impact simulates the compression of an imploding liner. A preliminary bench top system consisting of a low power laser, lenses, a beam rotator, a monochromator, and a PMT is being used for measuring the Rayleigh and eventually Raman scattering signals from atmospheric pressure N2 and O2. The laser is modulated at 500 Hz to 1 kHz and lock-in techniques are used to recover the low-amplitude signal. For the actual pulsed plasma experiment, the low-power laser will be replaced by a high power Nd:YAG laser. The detector will consist of a double monochromator consisting of two single monochromators separated by a mask in the focal plane to block Rayleigh scattered light; detection will be by an intensified, gated camera. The diagnostic will be used to study the compression and heating that occurs when the jet plasma collides with a dense, high mass target cloud. Supported by USDOE Grant DE-AR0000565.

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

    SciTech Connect

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

    2014-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

    Popa, Alexandru

    2011-08-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

    Ross, James Steven

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

    Bighel, L.; Cobble, J.A.

    1980-09-01

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

  19. A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak Project

    SciTech Connect

    Barth, C.J.; Beurskens, M.N.; Chu, C.C.; Donne, A.J.; Lopes Cardozo, N.J.; Herranz, J.; v.d. Meiden, H.J.; Pijper, F.J.

    1997-09-01

    A high resolution multiposition Thomson scattering setup to measure the electron temperature (T{sub e}) and density (n{sub e}) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera. T{sub e} in the range of 50 eV{endash}6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is {lt}6{percent} at n{sub e}=2{times}10{sup 19} m{sup {minus}3} and smaller for higher n{sub e}. The high resolution and accuracy enabled the observation of small scale structures in T{sub e} and n{sub e}. {copyright} {ital 1997 American Institute of Physics.}

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2016-11-01

    The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ0-210 nm) will be used to optimize the scattered signal for plasma densities of 5 × 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.

  4. Calibration of Thomson scattering systems using electron cyclotron emission cutoff data

    SciTech Connect

    Zhurovich, K.; Mossessian, D.A.; Hughes, J.W.; Hubbard, A.E.; Irby, J.H.; Marmar, E.S.

    2005-05-15

    An alternative method of absolute calibration of Thomson scattering (TS) systems is described. The method is based on the measurements of electron cyclotron emission (ECE) from the plasma. If the plasma density reaches some critical value the emission at some frequencies is cut off and an abrupt loss of signal is registered by the ECE diagnostic. These critical values are calculated from the frequencies of the ECE channels in which cutoffs are observed, using the dispersion relation for the wave propagation. The radial positions of the ECE channels are bound to the measured magnetic field in the tokamak and, therefore, are known. The derived critical density values at certain positions in plasma are used to calculate absolute calibration coefficients for the core TS system. For that data points from the TS diagnostic are interpolated in time and space to these critical density values. This calibration technique is implemented in situ on the Alcator C-Mod tokamak during plasma operation. We use a nine-channel ECE diagnostic to calibrate the eight-channel core TS system. The uncertainty of the TS density calibration is {<=}10%, which is less than that from the gas scattering calibrations. Good agreement exists between TS density profiles and measurements from the visible continuum diagnostic and interferometry. Given the wide availability of ECE diagnostics on most tokamaks and other fusion devices, this technique should be suitable on many other experiments.

  5. Thomson Scattering from Electron Plasma Waves in a Raman Plasma Amplifier

    NASA Astrophysics Data System (ADS)

    Davies, A.; Haberberger, D.; Bromage, J.; Zuegel, J. D.; Froula, D. H.; Trines, R.; Bingham, R.; Sadler, J.; Norreys, P. A.; Silva, L. O.

    2015-11-01

    Electron plasma waves (EPW's) can be used to transfer significant energy from a long-pulse laser to a short-seed pulse. Raman amplification has the potential to amplify intense pulses beyond the capabilities of current laser technology (~1022 W/cm2) because of the plasma's ability to sustain large-amplitude plasma waves. Having complete knowledge of the EPW amplitude is essential to establishing optimal parameters for efficient Raman amplification. With Thomson scattering it is possible to measure the spatial and temporal distribution of the EPW amplitude and experimentally determine the effect of the EPW profile on Raman scattering. Moving beyond the initial proof-of-principal experiments at the submillijoule level, to amplifying a 75-mJ, 100-fs seed with a 75-J pump has the potential to produce PW-scale laser pulses with Raman amplification. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  6. Investigation of thermodynamic equilibrium in laser-induced aluminum plasma using the Hα line profiles and Thomson scattering spectra

    NASA Astrophysics Data System (ADS)

    Cvejić, M.; DzierŻega, K.; Pieta, T.

    2015-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  8. Thomson scattering measurements of heat flux from ion-acoustic waves in laser-produced aluminum plasmas.

    PubMed

    Yu, Q Z; Zhang, J; Li, Y T; Lu, X; Hawreliak, J; Wark, J; Chambers, D M; Wang, Z B; Yu, C X; Jiang, X H; Li, W H; Liu, S Y; Zheng, Z J

    2005-04-01

    Thomson scattering (TS) measurements are performed at different locations in a laser-produced aluminum plasma. Variations of the separation, wavelength shift, and asymmetric distribution of the two ion-acoustic waves are investigated from their spectral-time-resolved TS images. Detailed information on the space-time evolution of the plasma parameters is obtained. Electron distribution and variation of the heat flux in the plasma are also obtained for a steep temperature gradient.

  9. Thomson Scattering Measurements of Temperature and Density in a Low-Density, Laser-Driven Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Schaeffer, D. B.; Montgomery, D. S.; Bondarenko, A. S.; Morton, L. A.; Johnson, R. P.; Shimada, T.; Constantin, C. G.; Everson, E. T.; Letzring, S. A.; Gaillard, S. A.; Flippo, K. A.; Glenzer, S. H.; Niemann, C.

    2012-02-01

    We present electron temperature and density measurements from Thomson scattering on recent collisionless shock experiments on the Trident laser at Los Alamos National Laboratory. A graphite target placed inside a static magnetic field (lesssim1 kG) created by a 50 cm-diameter Helmholtz coil was ablated by a 1053 nm beam, which created a low-density, magnetized plasma. A separate 527 nm beam was used for Thomson scattering to characterize the plasma 3 cm radially from the target and 0.5-8.5 μs after ablation. The electron temperature was found to be relatively constant over 8 μs at 11-13 eV and, combined with Rayleigh scattering, the electron density was found to be 2 × 1014-4 × 1014 cm-3 over the same timescale. Several carbon emission lines were also observed in the Thomson spectrum and were utilized to independently measure the electron temperature and density and to characterize the plasma charge state.

  10. Synchronization of Thomson scattering measurements on MAST using an FPGA based ``Smart'' trigger unit

    NASA Astrophysics Data System (ADS)

    Naylor, G.

    2010-10-01

    The MAST Thomson scattering diagnostic has recently been upgraded to make electron density and temperature measurements at 130 points across the 1.5 m diameter of the plasma. The new system is able to take 240 measurements per second using eight Nd:YAG lasers, each running at 30 Hz. The exact firing time of these lasers is adjusted with 100 ns precision using a field programmable gate array based trigger unit. Trigger pulses are produced to fire the lamps of all lasers and the Q switches with the appropriate delay depending on the warm-up status. The lasers may be fired in rapid bursts so as to achieve a high temporal resolution over eight points separated down to the microsecond level. This trigger unit receives optical trigger events and signals from external sources, allowing the trigger sequences to be resynchronized to the start of the plasma pulse and further events during the shot such as the entry of a fuelling pellet or randomly occurring plasma events. This resynchronization of the laser firing sequence allows accurate and reproducible measurements of fast plasma phenomena.

  11. Outline of optical design and viewing geometry for divertor Thomson scattering on MAST upgrade

    NASA Astrophysics Data System (ADS)

    Hawke, J.; Scannell, R.; Harrison, J.; Huxford, R.; Bohm, P.

    2013-11-01

    The super-X divertor on MAST Upgrade will be diagnosed by a Thomson scattering diagnostic. A preliminary design of the collection optics and calculations of the diagnostic's performance are discussed in this paper. As part of the design the location and size of the collection cell were optimized to minimize vignetting, especially in the region of interest close to the divertor strike point. The design process was complicated by the limited access available in the closed divertor geometry. In the study of the diagnostic's performance, the radial resolution, projection of the laser image onto the fiber bundle, and impact of depth of field with a multiple laser system were investigated. In this design there is a trade-off between the resolution of the system and the lifetime of the beam dump. For this reason the beam has its focal point at the start of the viewing region and diverges in width to approximately five millimeters near the divertor tile. The effect of this large variation in beam width is examined primarily at the two extremes by means of ray trace modeling. This model takes an object with dimensions of the beam width imaged onto the fiber bundle to investigate the effect of misalignment for a narrow or broad laser image. In a similar manner ray tracing was performed to determine the effects of depth of field for four and two laser systems. As the electron density of the system may be low, performance analysis considers firing multiple lasers simultaneously to improve photon statistics.

  12. Enhancement of the JET edge LIDAR Thomson scattering diagnostic with ultrafast detectors.

    PubMed

    Kempenaars, M; Flanagan, J C; Giudicotti, L; Walsh, M J; Beurskens, M; Balboa, I

    2008-10-01

    The edge light detection and ranging (LIDAR) Thomson scattering diagnostic at the Joint European Torus fusion experiment uses a 3 J ruby laser to measure the electron density and temperature profile at the plasma edge. The original system used a 1 GHz digitizer and detectors with response times of approximately 650 ps and effective quantum efficiencies <7%. This system has recently been enhanced with the installation of a new 8 GHz digitizer and four new ultrafast GaAsP microchannel plate photomultiplier tube detectors with response times of <300 ps and effective quantum efficiencies in the range of approximately 13%-20% (averaged over lambda=500-700 nm). This upgrade has enabled the spatial resolution to be reduced to approximately 6.3 cm along the laser line of sight for a laser pulse of 300 ps full width at half maximum, which is close to the requirements for the ITER core LIDAR. Performance analysis shows that the new system will have an effective spatial resolution of up to 1 cm in the magnetic midplane via magnetic flux surface mapping.

  13. Study of Fast, Near-Infrared Photodetectors for the ITER Core LIDAR Thomson Scattering

    NASA Astrophysics Data System (ADS)

    Giudicotti, L.; Pasqualotto, R.; Alfier, A.; Beurskens, M.; Kempenaars, M.; Walsh, M. J.

    2008-03-01

    A key component for the ITER core LIDAR Thomson Scattering (TS) diagnostic would be a detector with good sensitivity in the 850-1060 nm near infrared (NIR) spectral region. Covering this spectral region becomes necessary if a Nd:YAG laser system operating at λ = 1.06 μm is used as the laser source, which is a very attractive choice in terms of available energy, repetition rate, reliability and cost. In this paper we review the state of the art of two types of detectors available for the above spectral range: the transferred electron (TE) InGaAs/InP hybrid photodiode and the InxGa1-xAs microchannel plate (MCP) image intensifier and we describe the advancements necessary for a possible application in the ITER LIDAR TS. In addition we describe the preliminary characterization of new GaAsP fast MCP photomultipliers (PMTs) suitable for the detection of the visible part of the LIDAR TS spectrum in JET and ITER.

  14. A pulse-burst laser system for a high-repetition-rate Thomson scattering diagnostic.

    PubMed

    Den Hartog, D J; Jiang, N; Lempert, W R

    2008-10-01

    A "pulse-burst" laser system is being constructed for addition to the Thomson scattering diagnostic on the Madison Symmetric Torus (MST) reversed-field pinch. This laser is designed to produce a burst of up to 200 approximately 1 J Q-switched pulses at repetition frequencies 5-250 kHz. This laser system will operate at 1064 nm and is a master oscillator, power amplifier. The master oscillator is a compact diode-pumped Nd:YVO(4) laser, intermediate amplifier stages are flashlamp-pumped Nd:YAG, and final stages will be flashlamp-pumped Nd:glass (silicate). Variable pulse width drive (0.3-20 ms) of the flashlamps is accomplished by insulated-gate bipolar transistor switching of large electrolytic capacitor banks. The burst train of laser pulses will enable the study of electron temperature (T(e)) and electron density (n(e)) dynamics in a single MST shot, and with ensembling, will enable correlation of T(e) and n(e) fluctuations with other fluctuating quantities.

  15. A pulse-burst laser system for a high-repetition-rate Thomson scattering diagnostic

    SciTech Connect

    Den Hartog, D. J.; Jiang, N.; Lempert, W. R.

    2008-10-15

    A ''pulse-burst'' laser system is being constructed for addition to the Thomson scattering diagnostic on the Madison Symmetric Torus (MST) reversed-field pinch. This laser is designed to produce a burst of up to 200 approximately 1 J Q-switched pulses at repetition frequencies 5-250 kHz. This laser system will operate at 1064 nm and is a master oscillator, power amplifier. The master oscillator is a compact diode-pumped Nd:YVO{sub 4} laser, intermediate amplifier stages are flashlamp-pumped Nd:YAG, and final stages will be flashlamp-pumped Nd:glass (silicate). Variable pulse width drive (0.3-20 ms) of the flashlamps is accomplished by insulated-gate bipolar transistor switching of large electrolytic capacitor banks. The burst train of laser pulses will enable the study of electron temperature (T{sub e}) and electron density (n{sub e}) dynamics in a single MST shot, and with ensembling, will enable correlation of T{sub e} and n{sub e} fluctuations with other fluctuating quantities.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    SciTech Connect

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

    2012-07-15

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

  19. Ultraviolet Thomson Scattering from Direct-Drive Coronal Plasmas in Multilayer Targets

    NASA Astrophysics Data System (ADS)

    Henchen, R. J.; Goncharov, V. N.; Michel, D. T.; Follett, R. K.; Katz, J.; Froula, D. H.

    2014-10-01

    Ultraviolet (λ4 ω = 263 nm) Thomson scattering (TS) was used to probe ion-acoustic waves (IAW's) and electron plasma waves (EPW's) from direct-drive coronal plasmas. Fifty-nine drive beams (λ3 ω = 351 nm) illuminate a spherical target with a radius of ~ 860 μ m. A series of experiments studied the effect of higher electron temperature near the 3 ω quarter-critical surface (~ 2 . 5 ×1021 cm-3) on laser-plasma interactions resulting from a Si layer in the target. Electron temperatures and densities were measured from 150 to 400 μm from the initial target surface. Standard CH shells were compared to two-layered shells of CH and Si and three-layered shells of CH, Si, and CH. These multilayer targets have less hot-electron energy than standard CH shells as a result of higher electron temperature in the coronal plasmas. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

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

    SciTech Connect

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

    1993-12-31

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    NASA Astrophysics Data System (ADS)

    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

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

    SciTech Connect

    Brown, W J; Hartemann, F V

    2004-01-27

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

  4. Feasibility of alpha particle measurement in a magnetically confined plasma by CO/sub 2/ laser Thomson scattering

    SciTech Connect

    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/sub 2/ laser beam from such a plasma, a resonance in the scattered power occurs near 90/sup 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  8. Analysis of acoustic scattering from fluid bodies using a multipoint source model.

    PubMed

    Boag, A; Leviatan, Y

    1989-01-01

    A moment-method solution is presented for the problem of acoustic scattering from homogeneous fluid bodies. It uses fictitious isotropic point sources to simulate both the field scattered by the body and the field inside the body and, in turn, point-matches the continuity conditions for the normal component of the velocity and for the pressure across the surface of the body. The procedure is simple to execute and is general in that bodies of arbitrary smooth shape can be handled effectively. Perfectly rigid bodies are treated as reduced cases of the general procedure. Results are given and compared with available analytic solutions, which demonstrate the very good performance of the procedure.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  10. Evidence for out-of-equilibrium states in warm dense matter probed by x-ray Thomson scattering.

    PubMed

    Clérouin, Jean; Robert, Grégory; Arnault, Philippe; Ticknor, Christopher; Kress, Joel D; Collins, Lee A

    2015-01-01

    A recent and unexpected discrepancy between ab initio simulations and the interpretation of a laser shock experiment on aluminum, probed by x-ray Thomson scattering (XRTS), is addressed. The ion-ion structure factor deduced from the XRTS elastic peak (ion feature) is only compatible with a strongly coupled out-of-equilibrium state. Orbital free molecular dynamics simulations with ions colder than the electrons are employed to interpret the experiment. The relevance of decoupled temperatures for ions and electrons is discussed. The possibility that it mimics a transient, or metastable, out-of-equilibrium state after melting is also suggested.

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

    SciTech Connect

    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

    2003-07-01

    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{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

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

    NASA Astrophysics Data System (ADS)

    Lee, Kiyong

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

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

    PubMed

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

    2014-12-29

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

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

    SciTech Connect

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

    2014-08-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  16. Simultaneous measurement of electron and heavy particle temperatures in He laser-induced plasma by Thomson and Rayleigh scattering

    SciTech Connect

    Dzierzega, K.; Mendys, A.; Zawadzki, W.; Pokrzywka, B.; Pellerin, S.

    2013-04-01

    Thomson and Rayleigh scattering methods were applied to quantify the electron and heavy particle temperatures, as well as electron number density, in a laser spark in helium at atmospheric pressure. Plasma was created using 4.5 ns, 25 mJ pulses from Nd:YAG laser at 532 nm. Measurements, performed for the time interval between 20 ns and 800 ns after breakdown, show electron density and temperature to decrease from 7.8 Multiplication-Sign 10{sup 23} m{sup -3} to 2.6 Multiplication-Sign 10{sup 22} m{sup -3} and from 95 900 K to 10 350 K, respectively. At the same time, the heavy particle temperature drops from only 47 000 K down to 4100 K which indicates a two temperature plasma out of local isothermal equilibrium.

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

    SciTech Connect

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

    2014-11-15

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

  18. LIGHT SOURCE: RF deflecting cavity for bunch length measurement in Tsinghua Thomson scattering X-ray source

    NASA Astrophysics Data System (ADS)

    Shi, Jia-Ru; Chen, Huai-Bi; Tang, Chuan-Xiang; Huang, Wen-Hui; Du, Ying-Chao; Zheng, Shu-Xin; Ren, Li

    2009-06-01

    An RF deflecting cavity used for bunch length measurement has been designed and fabricated at Tsinghua University for the Thomson Scattering X-Ray Source. The cavity is a 2856 MHz, π-mode, 3-cell standing-wave cavity, to diagnose the 3.5 MeV beam produced by photocathode electron gun. With a larger power source, the same cavity will again be used to measure the accelerated beam with energy of 50 MeV before colliding with the laser pulse. The RF design using MAFIA for both the cavity shape and the power coupler is reviewed, followed by presenting the fabrication procedure and bench measurement results of two cavities.

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

    NASA Astrophysics Data System (ADS)

    Hack, Szabolcs; Varró, Sándor; Czirják, Attila

    2016-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed

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

    2015-04-01

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

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

    SciTech Connect

    Tracy, Mark David

    1993-01-08

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  4. Ultrafast K-alpha Thomson scattering from shock compressed matter for use as a dense matter diagnostic

    NASA Astrophysics Data System (ADS)

    Kritcher, Andrea Lynn

    Material conditions in the high-energy-density-physics regime relevant for the study of planetary formation, the modeling of planetary composition, and for inertial confinement fusion experiments, such as on the future National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL), can be produced and studied in the laboratory using high powered lasers that shock compress material to pressures greater than > 1 Mbar. Measurement of the compression and heating of shock-compressed dense matter at high pressures is fundamental in the study and understanding of the physical and chemical properties of these extreme states. Investigation of the behavior of the ionic and elecronic properties in this regime is important to determine the equation of state and thermodynamic properties of materials under extreme conditions, that are not currently well understood. In previous work, x-ray Thomson scattering has been employed to characterize dense matter conditions, ne > 3 x 10 21cm-3, that cannot be probed using the well established technique of optical Thomson scattering. These experiments employed x-ray probes with a temporal resolution of 100 ps. However, for the full characterization of strong shocks in dense matter, an x-ray source that provides picosecond temporal resolution, i.e. K-alpha x-rays, is desirable. Presented in this thesis, are the first spectrally and temporally resolved x ray Thomson scattering measurements using ultrafast (10 ps) Ti K-alpha x-rays. These measurements have provided experimental validation for modeling of the compression and heating of shocked matter. The coalescence of two shocks launched into a solid density LiH target by a shaped 6 nanosecond heater beam was observed from rapid heating to temperatures of 2.2 eV, enabling tests of shock timing models, mainly dependent on choice of Equation of State (EOS). Here, the temperature evolution of the target at various times during shock progression was characterized from the

  5. High-repetition-rate pulse-burst laser for Thomson scattering on the MST reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Young, W. C.; Morton, L. A.; Parke, E.; Den Hartog, D. J.

    2013-11-01

    A new, high-repetition-rate pulse-burst laser system for the MST Thomson scattering diagnostic has operated with 2 J pulses at repetition rates up to 75 kHz within a burst. The 1064 nm laser currently employs a q-switched, diode pumped Nd:YVO4 master oscillator, four Nd:YAG amplifier stages, and a Nd:glass amplifier, with plans for an additional Nd:glass amplifier. The laser can maintain 1.5-2 J pulses in two operating modes: either at a uniform repetition rate of 5-10 kHz (sustained for 5-8 ms), or reach rates of up to 75 kHz in pulse-burst operation (for 10 bursts of 15 pulses each), limited by flashlamp explosion energy and wall loading. The full system, including an additional Nd:glass amplifier, is designed to produce bursts of 2 J pulses at a repetition rate of at least 250 kHz. Custom programmable square-pulse power supplies drive the amplifier flashlamps, providing fine control of pulse timing, duration, and repetition, and allow for pulse-burst operation. The new laser system integrates with the same collection optics and detectors as used by the previous MST Thomson laser: 21 spatial points across the MST minor radius, filter polychromators with 6 to 8 channels (10 eV-5 keV range), avalanche photodiode detectors, and 1 GSample/s/channel digitization. Use of the previous pulse-burst laser continues concurrently with new laser development. Additional notes on optimization of flashlamp simmering will also be covered, showing that an increase in simmer currents can improve pulse-to-pulse energy consistency on both the new and older lasers.

  6. First-principles calculations of dynamic transport properties for x-ray Thomson scattering experiments on warm dense aluminum

    NASA Astrophysics Data System (ADS)

    Witte, Bastian B. L.; Sperling, Philipp; Glenzer, Siegfried H.; Redmer, Ronald

    2016-10-01

    X-ray Thomson scattering (XRTS) is an effective tool to determine plasma parameters, e.g., temperature and density, in the warm dense (WD) matter regime. Furthermore, transport coefficients are relevant for modeling, e.g., fusion experiments or the magnetic field generation in planets. Recently, the electrical conductivity was extracted for the first time from XRTS experiments on aluminum, isochorically heated by the Linac Coherent Light Source (LCLS). The measured spectrally resolved scattering signal shows a strong dependence on the electron interactions, which have to be treated beyond perturbation theory. We present results for the dynamic transport properties in WD aluminum using density-functional-theory molecular dynamics (DFT-MD) simulations. The choice of the exchange-correlation (XC) functional, describing the interactions in the electronic subsystem, has significant impact on the ionization potential and the thermal and electrical conductivity. The calculation of the XRTS signal from the DFT-MD simulations shows very good agreement with the LCLS data if hybrid functionals are applied, i.e., XC functionals within the generalized gradient approximation are not suitable for the description of WD aluminum.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

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

    SciTech Connect

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

    2012-09-15

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

  9. Ultraviolet Thomson Scattering from Two-Plasmon-Decay Driven Electron Plasma Waves at Quarter-Critical Densities

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    Thomson scattering (TS) was used to probe electron plasma waves (EPW's) driven by the two-plasmon-decay (TPD) instability near quarter-critical density. TPD-driven EPW's were observed at densities consistent with the common-wave TPD model. Five laser beams (λ3ω = 351nm) produced 400- μm-diam (FWHM) laser spots with overlapped intensities up to 3 ×1014W/cm2 . A 263-nm TS beam was used to probe densities ranging from 0.18 to 0.26 nc, where nc is the critical density for 351-nm light. The experimental geometry was chosen to match the five-beam TPD common wave k vector. The TS spectrum shows a large amplitude, narrow (~1.6-nm FHWM) feature centered around 423.4 nm. This wavelength corresponds to scattering from EPW's with a normalized wave vector k / k3 ω = 1 . 3 , a density of ne/nc = 0.243, and a temperature of Te = 2 keV. This is consistent with the predicted values given by the dispersion relations and TPD maximum growth hyperbola. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

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

    PubMed

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

    2012-09-01

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

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

    SciTech Connect

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

    2015-07-13

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

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

    SciTech Connect

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

    1991-12-31

    We have developed 5-channel collective Thomson scattering system to measure the ion acoustic wave excited by the ion acoustic wave decay instabilities. The multichannel collective Thomson scattering technique was established with 4{omega} probe laser beam using GDL laser system at LLE, Univ. of Rochester. We have obtained the ionic charge state Z by measuring the second harmonic emission from the ion acoustic decay instability. The LASNEX computer simulation calculations have been carried out. The experimental results agree very well with the LASNEX computer simulation results with the flux number f=0.1. In high power laser regime, the spectrum become broad, and the {alpha}{gamma} decreases indicating that the turbulent like spectrum is observed. In order to understand the experimental results, we have developed a theory to study absorption of laser and heat transport. This new theory includes the temporal evolution of the heat conduction region. The results agree with flux-limited hydrodynamic simulations. 20 refs.

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

    SciTech Connect

    Mizuno, K.; DeGroot, J.S. ); Seka, W. . Lab. for Laser Energetics)l Drake, R.P. )

    1991-01-01

    We have developed 5-channel collective Thomson scattering system to measure the ion acoustic wave excited by the ion acoustic wave decay instabilities. The multichannel collective Thomson scattering technique was established with 4{omega} probe laser beam using GDL laser system at LLE, Univ. of Rochester. We have obtained the ionic charge state Z by measuring the second harmonic emission from the ion acoustic decay instability. The LASNEX computer simulation calculations have been carried out. The experimental results agree very well with the LASNEX computer simulation results with the flux number f=0.1. In high power laser regime, the spectrum become broad, and the {alpha}{gamma} decreases indicating that the turbulent like spectrum is observed. In order to understand the experimental results, we have developed a theory to study absorption of laser and heat transport. This new theory includes the temporal evolution of the heat conduction region. The results agree with flux-limited hydrodynamic simulations. 20 refs.

  14. Quenching of the nonlocal electron heat transport by large external magnetic fields in a laser produced plasma measured with imaging Thomson scattering

    SciTech Connect

    Froula, D H; Davis, P; Pollock, B B; Divol, L; Ross, J S; Edwards, J; Town, R; Price, D; Glenzer, S H; Offenberger, A A; Tynan, G R; James, A N

    2006-04-14

    We present a direct measurement of the quenching of nonlocal heat transport in a laser produced plasma by high external magnetic fields. Temporally resolved measurements of the electron temperature profile transverse to a high power laser beam were obtained using imaging Thomson scattering. The results are simulated with the 2D hydrodynamic code LASNEX with a recently included magnetic field model that self-consistently evolves the fields in the plasma.

  15. Ultrafast X-ray Thomson Scattering of Shock-Compressed Matter

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

    Spectrally resolved scattering of ultrafast K-α x-rays has provided experimental validation of the modeling of the compression and heating of shocked matter. The elastic scattering component has characterized the evolution and coalescence of two shocks launched by a nanosecond laser pulse into lithium hydride with an unprecedented temporal resolution of 10 picoseconds. At shock coalescence, we observed rapid heating to temperatures of 25,000 kelvin when the scattering spectra show the collective plasmon oscillations that indicate the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of 3, thereby reaching conditions in the laboratory relevant for studying the physics of planetary formation.

  16. Observations of Continuum Depression in Warm Dense Matter with X-Ray Thomson Scattering

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    Detailed measurements of the electron densities, temperatures, and ionization states of compressed CH shells approaching pressures of 50 Mbar are achieved with spectrally resolved x-ray scattering. Laser-produced 9 keV x-rays probe the plasma during the transient state of three-shock coalescence. High signal-to-noise x-ray scattering spectra show direct evidence of continuum depression in highly degenerate warm dense matter states with electron densities ne>1024 cm-3. The measured densities and temperatures agree well with radiation-hydrodynamic modeling when accounting for continuum lowering in calculations that employ detailed configuration accounting.

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

    NASA Astrophysics Data System (ADS)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

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

    DOE PAGES

    Ao, T.; Harding, E. C.; Bailey, J. E.; ...

    2016-01-13

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

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

    SciTech Connect

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

    2016-01-13

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

  20. Customizable electron beams from optically controlled laser plasma acceleration for γ-ray sources based on inverse Thomson scattering

    NASA Astrophysics Data System (ADS)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2016-09-01

    Laser wakefield acceleration of electrons in the blowout regime can be controlled by tailoring the laser pulse phase and the plasma target. The 100 nm-scale bandwidth and negative frequency chirp of the optical driver compensate for the nonlinear frequency red-shift imparted by wakefield excitation. This mitigates pulse self-steepening and suppresses continuous injection. The plasma channel suppresses diffraction of the pulse leading edge, further reducing self-steepening, making injection even quieter. Besides, the channel destabilizes the pulse tail confined within the accelerator cavity (the electron density "bubble"), causing oscillations in the bubble size. The resulting periodic injection generates background-free comb-like beams - sequences of synchronized, low phase-space volume bunches. Controlling the number of bunches, their energy, and energy spacing by varying the channel radius and the pulse length (as permitted by the large bandwidth) enables the design of a tunable, all-optical source of polychromatic, pulsed γ-rays using the mechanism of inverse Thomson scattering. Such source may radiate ~107 quasi-monochromatic 10 MeV-scale photons per shot into a microsteradian-scale observation angle. The photon energy is distributed among several distinct bands, each having sub-25% energy spread dictated by the mrad-scale divergence of electron beam.

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

    PubMed

    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.

  2. High-power pulsed gyrotron for 300 GHz-band collective Thomson scattering diagnostics in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yuusuke; Saito, Teruo; Tatematsu, Yoshinori; Ikeuchi, Shinji; Manuilov, Vladimir N.; Kasa, Jun; Kotera, Masaki; Idehara, Toshitaka; Kubo, Shin; Shimozuma, Takashi; Tanaka, Kenji; Nishiura, Masaki

    2015-01-01

    A high-power pulse gyrotron was developed to generate a probe wave for 300 GHz-band collective Thomson scattering (CTS) diagnostics in the Large Helical Device. In this frequency range, avoiding mode competition is critical to realizing high-power and stable oscillation with a narrow frequency bandwidth. A moderately over-moded cavity was investigated to ensure sufficient isolation of a desired mode from neighbouring modes, and to achieve high power output simultaneously. A cavity with the TE14,2 operation mode, a triode electron gun with an intense laminar electron beam, and an internal mode convertor were designed to construct a prototype tube. It was experimentally observed that oscillation of the TE14,2 mode was strong enough for mode competition, and provided high power with sufficient stability. The oscillation characteristics associated with the electron beam properties were compared with the numerical characteristics to find an optimum operating condition. As a result, single-mode operation with maximum output power of 246 kW was demonstrated at 294 GHz with 65 kV/14 A electron beam, yielding efficiency of ˜27%. The radiation pattern was confirmed to be highly Gaussian. The duration of the 130 kW pulse, which is presently limited by the power supply, was extended up to 30 µs. The experimental results validate our design concept and indicate the potential for realizing a gyrotron with higher power and longer pulse toward practical use in 300 GHz CTS diagnostics.

  3. Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium

    NASA Astrophysics Data System (ADS)

    Harbour, L.; Dharma-wardana, M. W. C.; Klug, D. D.; Lewis, L. J.

    2016-11-01

    Ultrafast laser experiments yield increasingly reliable data on warm dense matter, but their interpretation requires theoretical models. We employ an efficient density functional neutral-pseudoatom hypernetted-chain (NPA-HNC) model with accuracy comparable to ab initio simulations and which provides first-principles pseudopotentials and pair potentials for warm-dense matter. It avoids the use of (i) ad hoc core-repulsion models and (ii) "Yukawa screening" and (iii) need not assume ion-electron thermal equilibrium. Computations of the x-ray Thomson scattering (XRTS) spectra of aluminum and beryllium are compared with recent experiments and with density-functional-theory molecular-dynamics (DFT-MD) simulations. The NPA-HNC structure factors, compressibilities, phonons, and conductivities agree closely with DFT-MD results, while Yukawa screening gives misleading results. The analysis of the XRTS data for two of the experiments, using two-temperature quasi-equilibrium models, is supported by calculations of their temperature relaxation times.

  4. Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system.

    PubMed

    Tojo, H; Hatae, T; Hamano, T; Sakuma, T; Itami, K

    2013-09-01

    Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ~0.3 mm and ~0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30 keV) can be expected in the refraction system.

  5. Post shot analysis of plasma conditions of Gold Spheres illuminated by the URLLE Omega laser, as measured via Thomson scattering

    NASA Astrophysics Data System (ADS)

    Rosen, M. D.; Ross, J. S.; Scott, H. A.; Landen, N.; Froula, D.; Dewald, E.; May, M.; Widmann, K.

    2013-10-01

    Recently there was a follow up to the 2006 campaign to illuminate 1 mm diameter gold spheres using the Omega laser at LLE. The 2013 campaign uses Thomson scattering to diagnose the plasma conditions as a function of time, at various radial positions in the coronal, laser heated, blow-off region. Laser irradiances were 1, 5, and 10 × 1014 W/sqcm, usually in a 1 ns pulse duration. Depleted uranium and Ag spheres were also tested. We compare the predictions of plasma conditions using various non-LTE computational models of atomic physics and electron transport (as implemented into the rad-hydro code Lasnex) to this data. The ``high flux model (HFM)'' (DCA atomic physics and non local transport) compares well for some of experiments, while an intermediate model that radiates a bit less total x-ray fluence than the HFM, does better on other experiments. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

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

    NASA Astrophysics Data System (ADS)

    Tojo, H.; Yamada, I.; Yasuhara, R.; Ejiri, A.; Hiratsuka, J.; Togashi, H.; Yatsuka, E.; Hatae, T.; Funaba, H.; Hayashi, H.; Takase, Y.; Itami, K.

    2016-09-01

    This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (Te) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured Te and intensity of the signals. How accurate the values are depends on the electron temperature (Te) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high Te and a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the Te in a wide Te range spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the Te measurements are valid under harsh radiation conditions. This method to obtain Te can be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.

  7. Design and development of detector signal conditioning electronics for SST-1 Thomson scattering system

    SciTech Connect

    Thakar, Aruna; Kumar, Ajai; Thomas, Jinto; Chavda, Chhaya

    2008-09-15

    An IR enhanced thermoelectrically cooled Si-avalanche photodiode (Si-APD) module is used for detection of scattered photons from plasma electrons. Present design of signal conditioning electronics for the APD has fast (50 MHz) and slow (500 kHz) channels to measure scattered and plasma background light, respectively. We report design analysis for different stages and their performance. The performance of fast channel is analyzed for two different group delays, speed, linearity, and its cross-talk with slow channel. Temperature dependence of APD's responsivity is studied in the wavelength range of 900-1060 nm. A minimum detection of {approx}25 photoelectrons (with S/N=1) in the range of 5 to 25 deg. C is achieved at an APD gain of 75 in the present design.

  8. Resonant bound-free contributions to Thomson scattering of X-rays by warm dense matter

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.; Cheng, K. T.

    2013-09-01

    Recent calculations [Nilsen et al. arXiv:1212.5972] predict that contributions to the scattered photon spectrum from 3s and 3p bound states in chromium (Z = 24) at metallic density and T = 12 eV resonate below the respective bound-state thresholds. These resonances are shown to be closely related to continuum lowering, where 3d bound states in the free atom dissolve into a resonant l = 2 partial wave in the continuum. The resulting d-state resonance dominates contributions to the bound-free dynamic structure function, leading to the predicted resonances in the scattered X-ray spectrum. Similar resonant features are shown to occur in all elements in the periodic table between Ca and Mn (20 ≤ Z ≤ 25).

  9. COMPUTING THE CONTINUUM POLARIZATION FROM THOMSON SCATTERING IN GASEOUS CIRCUMSTELLAR DISKS

    SciTech Connect

    Halonen, R. J.; Mackay, F. E.; Jones, C. E.

    2013-01-15

    We investigate the computation of the intrinsic continuum linear polarization from electron scattering in optically thin and thick circumstellar disks of gas. We present the use of a non-LTE radiative transfer code, along with two different computational methods for obtaining the Stokes parameters, to reproduce the polarization levels that arise from disks of classical Be stars. Since the pioneering work of Poeckert and Marlborough, numerous improvements and refinements have been incorporated into computational radiative transfer models of classical Be stars. We present an assessment of the effect of several improvements on Poeckert and Marlborough's technique for calculating the polarization levels of the classical Be star {gamma} Cas. We find that improvements to the sampling of the disk density and the inclusion of a non-isothermal structure for the gas in the disk yield polarization levels that differ from the levels expected by Poeckert and Marlborough. Principally, the inclusion of the self-consistent calculation of the thermal structure of the disk has a significant impact on the resulting polarization. In addition, we assess the importance of the inclusion of multiple scattering calculations in predicting the continuum polarization in classical Be stars. We confirm that multiple scattering calculations are necessary for studying the linear polarization levels from optically thick gaseous disks around classical Be stars.

  10. T-REX: Thomson-Radiated Extreme X-rays Moving X-Ray Science into the ''Nuclear'' Applications Space with Thompson Scattered Photons

    SciTech Connect

    Barty, C P; Hartemann, F V

    2004-09-21

    The scattering of laser photons from relativistic electrons (Thomson scattering) has been demonstrated to be a viable method for the production of ultrashort-duration pulses of tunable radiation in the 10-keV to 100-keV range. Photons in this range are capable of exciting or ionizing even the most tightly bound of atomic electrons. A wide variety of atomistic scale applications are possible. For example, Thomson x-ray sources have been constructed at LLNL (PLEIADES) and LBL as picosecond, stroboscopic probes of atomic-scale dynamics and at Vanderbilt University as element-specific tools for medical radiography and radiology. While these sources have demonstrated an attractive ability to simultaneously probe on an atomic spatial and temporal scale, they do not necessarily exploit the full potential of the Thomson scattering process to produce high-brightness, high-energy photons. In this white paper, we suggest that the peak brightness of Thomson sources can scale as fast as the 4th power of electron beam energy and that production via Thomson scattering of quasi-monochromatic, tunable radiation in the ''nuclear-range'' between 100-keV and several MeV is potentially a much more attractive application space for this process. Traditional sources in this regime are inherently ultra-broadband and decline rapidly in brightness as a function of photon energy. The output from dedicated, national-laboratory-scale, synchrotron facilities, e.g. APS, SPring8, ESRF etc., declines by more than 10 orders from 100 keV to 1 MeV. At 1 MeV, we conservatively estimate that Thomson-source, peak brightness can exceed that of APS (the best machine in the DOE complex) by more than 15 orders of magnitude. In much the same way that tunable lasers revolutionized atomic spectroscopy, this ''Peta-step'' advance in tunable, narrow-bandwidth, capability should enable entirely new fields of study and new, programmatically-interesting, applications such as: micrometer-spatial-resolution, Me

  11. Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system

    SciTech Connect

    Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K.

    2013-09-15

    Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ∼0.3 mm and ∼0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30 keV) can be expected in the refraction system.

  12. Thomson scattering and collisional ionization in the X-ray grating spectra of the recurrent nova U Scorpii

    NASA Astrophysics Data System (ADS)

    Orio, M.; Behar, E.; Gallagher, J.; Bianchini, A.; Chiosi, E.; Luna, G. J. M.; Nelson, T.; Rauch, T.; Schaefer, B. E.; Tofflemire, B.

    2013-02-01

    We present a Chandra observation of the recurrent nova U Scorpii, done with the High Resolution camera-S (HRC-S) detector and the Low Energy Transmission Grating (LETG) on day 18 after the observed visual maximum of 2010, and compare it with XMM-Newton observations obtained on days 23 and 35 after maximum. The total absorbed flux was in the range 2.2-2.6 × 10-11 erg cm-2 s-1, corresponding to unabsorbed luminosity 7-8.5 × 1036 ×(d/12 kpc)2 for N(H) = 2-2.7 × 1021 cm-2. On day 18, 70 per cent of the soft X-tray flux was in a continuum typical of a very hot white dwarf (WD) atmosphere, which accounted for about 80 per cent of the flux on days 23 and 35. In addition, all spectra display very broad emission lines, due to higher ionization stages at later times. With Chandra we observed apparent P Cygni profiles. We find that these peculiar profiles are not due to blueshifted absorption and redshifted emission in photoionized ejecta, like the optical P Cyg of novae, but they are rather a superposition of WD atmospheric absorption features reflected by the already discovered Thomson scattering corona, and emission lines due to collisional ionization in condensations in the ejecta. On days 23 and 35, the absorption components were no longer measurable, having lost the initial large blueshift that displaced them from the core of the broad emission lines. We interpret this as an indication that mass-loss ceased between day 18 and day 23. On day 35, the emission line spectrum became very complex, with several different components. Model atmospheres indicate that the WD atmospheric temperature was about 730 000 K on day 18 and reached 900 000-1000 000 K on day 35. This peak temperature is consistent with a WD mass of at least 1.3 M⊙.

  13. Development of an Internet-Enabled Tool for NSTX-U Thomson Diagnostic Data

    NASA Astrophysics Data System (ADS)

    Wallace, William; Diallo, Ahmed

    2016-10-01

    MultiPoint Thomson Scattering (MPTS) is an established, accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Two Nd:YAG (1064 nm) lasers are fired into the plasma with a effective frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the NSTX-U midplane collect the scattered photons at various radii/scattering angles, and the avalanche photodiode voltages are saved to an MDSplus tree for later analysis. IDL code is then used to determine plasma temperature, pressure, and density from the captured polychromator measurements via Selden formulas.[1] OMFIT, from the General Atomics Fusion Theory Team, is a rich data workflow package used on DIII-D, NSTX-U, and other experiments to rapidly investigate and draw conclusions from collated data sets and simulations. OMFIT can also be used as a data access source into other toolkits and fusion analysis software. This project, written in Python and taking advantage of late-generation Internet software technologies, uses OMFIT to rapidly find and visualize Thomson diagnostic plasma characteristics enabling scientists to gain a quick understanding of shot behavior and timeframes.

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

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

    To determine the fine-structure size of plasmas created by a Microwave Plasma Torch (MPT), single-shot Thomson scattering (TS) measurements were performed. The aim was to find a solution for the long-standing discrepancy between experiments and Global Plasma Models (GPMs). Since these GPMs are based on the assumption that (ambipolar) diffusion is the main loss process for charged particles, the diffusion length and thus the fine-structure size should be known with high precision before an appropriate theory-experiment comparison can be carried out. In order to avoid the effect of blurring, which is created during the accumulation of multi-shot TS signals and which obscures the fine-structures, single-shot measurements are indispensable to determine the diffusion length. The results of the present study reveal that the impression created by multi-shot TS that MPT plasmas resemble stable cones is not (always) correct; instead it is found that the plasmas we investigated are tiny filaments that rotate on the mantle of a virtual cone. However, the fine-structure, especially the thickness, of these filaments is not substantially smaller than that of the virtual cone. By applying the theory-experiment comparison to the filament we found that the disagreement is even worse than what we found for the cone. It is therefore inevitable to conclude that the main proposition of the GPM is incorrect. Apparently the plasma is not diffusive in nature; that is, the main loss process of charged particles is not provided by diffusion but by local chemistry. Swirling in a cool nitrogen-containing environment favors the production of molecular ions such as Ar 2+ and N 2+ inside the plasma filament. The destruction of these molecular ions leads to recombination frequencies that are more than a factor 100 larger than what ambipolar diffusion can provide. Thus we are dealing with another plasma class and it is useful to divide plasmas into diffusive and reactive plasmas. The well

  15. Multipoint multirate signal processing

    NASA Astrophysics Data System (ADS)

    Claypoole, Roger L., Jr.

    1994-12-01

    This thesis provides a fundamentally new, systematic study of multipoint multirate signal processing systems. The multipoint multirate operators are analyzed via equivalent circuits comprised entirely of conventional multirate operators. Interconnections of the operators are demonstrated, and the multipoint noble identities are derived. The multipoint polyphase representation is presented, and the M channel multipoint multirate system with vector length N is presented as an MN channel multipoint polyphase system. The conditions sufficient for perfect reconstruction in the multipoint multirate system are derived. These conditions constrain the multipoint filter banks to be composed of comb filters generated from paraunitary sets of conventional filters. The perfect reconstruction multipoint multirate system is then combined with the multiresolution wavelet decomposition to form the generalized wavelet decomposition with varying vector decimation length at each level. The generalized wavelet decomposition is used as an algorithm to redistribute the energy of a signal throughout the levels of the decomposition. It is shown that, for band pass and high pass signals, significant improvements can be made in the energy distribution. It is recommended that this algorithm be studied as a front end to a vector quantizer for data compression applications.

  16. Continued Development of Python-Based Thomson Data Analysis and Associated Visualization Tool for NSTX-U

    NASA Astrophysics Data System (ADS)

    Wallace, William; Miller, Jared; Diallo, Ahmed

    2015-11-01

    MultiPoint Thomson Scattering (MPTS) is an established, accurate method of finding the temperature, density, and pressure of a magnetically confined plasma. Two Nd:YAG (1064 nm) lasers are fired into the plasma with a effective frequency of 60 Hz, and the light is Doppler shifted by Thomson scattering. Polychromators on the NSTX-U midplane collect the scattered photons at various radii/scattering angles, and the avalanche photodiode voltages are saved to an MDSplus tree for later analysis. IDL code is then used to determine plasma temperature, pressure, and density from the captured polychromator measurements via Selden formulas. [1] Previous work [2] converted the single-processor IDL code into Python code, and prepared a new architecture for multiprocessing MPTS in parallel. However, that work was not completed to the generation of output data and curve fits that match with the previous IDL. This project refactored the Python code into a object-oriented architecture, and created a software test suite for the new architecture which allowed identification of the code which generated the difference in output. Another effort currently underway is to display the Thomson data in an intuitive, interactive format. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Community College Internship (CCI) program.

  17. Design and engineering of a target for x-ray Thomson scattering measurements on matter at extreme densities and gigabar pressures

    SciTech Connect

    Boehm, K. -J.; Hash, N.; Barker, D.; Doppner, T.; Farrell, M. P.; Fitzsimmons, P.; Kaczala, D.; Kraus, D.; Maranville, B.; Mauldin, M.; Neumayer, P.; Segraves, K.

    2016-06-24

    Reconciling the experimental and system requirements during the development of a new target system is one of the most challenging tasks in the design and engineering of targets used in the National Ignition Facility. Targets for the GigaBar 3 campaign were meant to allow the detection of extremely weak Thomson scattering from matter at extreme densities in the face of very bright backlighter and laser entry hole plasma emissions. The problem was to shield the detector sufficiently while maintaining beamline and view clearances, and observing target mass restrictions. A new construction process, based on a rapid prototype frame structure, was used to develop this target. As a result, details of the design process for these targets are described, and lessons from this development for production and target assembly teams are discussed.

  18. Design and engineering of a target for x-ray Thomson scattering measurements on matter at extreme densities and gigabar pressures

    DOE PAGES

    Boehm, K. -J.; Hash, N.; Barker, D.; ...

    2016-06-24

    Reconciling the experimental and system requirements during the development of a new target system is one of the most challenging tasks in the design and engineering of targets used in the National Ignition Facility. Targets for the GigaBar 3 campaign were meant to allow the detection of extremely weak Thomson scattering from matter at extreme densities in the face of very bright backlighter and laser entry hole plasma emissions. The problem was to shield the detector sufficiently while maintaining beamline and view clearances, and observing target mass restrictions. A new construction process, based on a rapid prototype frame structure, wasmore » used to develop this target. As a result, details of the design process for these targets are described, and lessons from this development for production and target assembly teams are discussed.« less

  19. Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments

    NASA Astrophysics Data System (ADS)

    Lu, J.; Hill, K. W.; Bitter, M.; Pablant, N. A.; Delgado-Aparicio, L. F.; Efthimion, P. C.; Lee, H. J.; Zastrau, U.

    2017-01-01

    We have proposed, designed and built a dual-channel x-ray imaging crystal spectrometer (XICS) for spectrally- and spatially-resolved x-ray Thomson scattering (XRTS) measurements in the Matter in Extreme Conditions (MEC) end station at the Linac Coherent Light Source (LCLS). This spectrometer employs two spherically-bent germanium (Ge) 220 crystals, which are combined to form a large aperture dispersive element with a spectral bandwidth of 300 eV that enables both the elastic and inelastic x-ray scattering peaks to be simultaneously measured. The apparatus and its characterization are described. A resolving power of 1900 was demonstrated and a spatial resolution of 12 μm was achieved in calibration tests. For XRTS measurements, a narrow-bandwidth (ΔE/E<0.003) LCLS x-ray free electron laser (XFEL) beam at 5.07 keV was used to probe a dense carbon plasma produced in shock-compressed samples of different forms of carbon. Preliminary results of the scattering experiments from Pyrolytic Graphite samples that illustrate the utility of the instrument are presented.

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

    NASA Astrophysics Data System (ADS)

    MacDonald, M. J.; Gorkhover, T.; Bachmann, B.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Ferguson, K. R.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Hau-Riege, S. P.; Kraus, D.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K.-H.; O'Grady, C. P.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Swiggers, M.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-11-01

    Atomic clusters can serve as ideal model systems for exploring ultrafast (˜100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization. Single shot x-ray Thomson scattering signals were recorded at 120 Hz using a crystal spectrometer in combination with a single-photon counting and energy-dispersive pnCCD. A precise pump laser collimation scheme enabled recording near background-free scattering spectra from Ar clusters with an unprecedented dynamic range of more than 3 orders of magnitude. Such measurements are important for understanding collective effects in laser-matter interactions on femtosecond time scales, opening new routes for the development of schemes for their ultrafast control.

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

    SciTech Connect

    MacDonald, M. J.; Gorkhover, T.; Bachmann, B.; Bucher, M.; Carron, S.; Coffee, R. N.; Drake, R. P.; Ferguson, K. R.; Fletcher, L. B.; Gamboa, E. J.; Glenzer, S. H.; Göde, S.; Hau-Riege, S. P.; Kraus, D.; Krzywinski, J.; Levitan, A. L.; Meiwes-Broer, K. -H.; O’Grady, C. P.; Osipov, T.; Pardini, T.; Peltz, C.; Skruszewicz, S.; Swiggers, M.; Bostedt, C.; Fennel, T.; Döppner, T.

    2016-08-08

    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 scatterings 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. As a result, such measurements are important for understanding collective effects in laser-matter interactions on femtosecond timescales, opening new routes for the development of schemes for their ultrafast control.

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

    DOE PAGES

    MacDonald, M. J.; Gorkhover, T.; Bachmann, B.; ...

    2016-08-08

    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 scatterings signals were recorded at 120 Hz using a crystal spectrometer in combination withmore » 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. As a result, such measurements are important for understanding collective effects in laser-matter interactions on femtosecond timescales, opening new routes for the development of schemes for their ultrafast control.« less

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

    NASA Astrophysics Data System (ADS)

    Corvan, D. J.; Zepf, M.; Sarri, G.

    2016-09-01

    γ-Ray sources are among the most fundamental experimental tools currently available to modern physics. As well as the obvious benefits to fundamental research, an ultra-bright source of γ-rays could form the foundation of scanning of shipping containers for special nuclear materials and provide the bases for new types of cancer therapy. However, for these applications to prove viable, γ-ray sources must become compact and relatively cheap to manufacture. In recent years, advances in laser technology have formed the cornerstone of optical sources of high energy electrons which already have been used to generate synchrotron radiation on a compact scale. Exploiting the scattering induced by a second laser, one can further enhance the energy and number of photons produced provided the problems of synchronisation and compact γ-ray detection are solved. Here, we report on the work that has been done in developing an all-optical and hence, compact non-linear Thomson scattering source, including the new methods of synchronisation and compact γ-ray detection. We present evidence of the generation of multi-MeV (maximum 16-18 MeV) and ultra-high brilliance (exceeding 1020 photons s-1mm-2mrad-2 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above.

  4. Demonstration of improvement in the signal-to-noise ratio of Thomson scattering signal obtained by using a multi-pass optical cavity on the Tokyo Spherical Tokamak-2

    SciTech Connect

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

    2014-11-15

    The multi-pass Thomson scattering (TS) scheme enables obtaining many photons by accumulating multiple TS signals. The signal-to-noise ratio (SNR) depends on the accumulation number. In this study, we performed multi-pass TS measurements for ohmically heated plasmas, and the relationship between SNR and the accumulation number was investigated. As a result, improvement of SNR in this experiment indicated similar tendency to that calculated for the background noise dominant situation.

  5. Nonlinear effects in Thomson backscattering

    NASA Astrophysics Data System (ADS)

    Maroli, C.; Petrillo, V.; Tomassini, P.; Serafini, L.

    2013-03-01

    We analyze the nonlinear classical effects of the X/γ radiation produced by Thomson/Compton sources. We confirm the development of spectral fringes of the radiation on axis, which comports broadening, shift, and deformation of the spectrum. For the nominal parameters of the SPARC-LAB Thomson scattering and of the European Proposal for the gamma source ELI-NP, however, the radiation, when collected in the suitable acceptance angle, does not reveal many differences from that predicted by the linear model and the nonlinear redshift is subdominant with respect to the quantum recoil. An experiment aimed to the study of the nonlinearities is proposed on the SPARC-LAB source.

  6. Ultra-fast x-ray Thomson scattering measurements of insulator-metal transition in shock-compressed matter

    SciTech Connect

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

    2008-05-16

    Spectrally resolved scattering of ultra-short pulse laser-generated K-{alpha} x rays has been applied to measure the heating and compression of shocked solid-density lithium hydride. Two shocks launched by a nanosecond laser pulse coalesce yielding pressures of 400 gigapascals. The evolution of the intensity of the elastic (Rayleigh) scattering component indicates rapid heating to temperatures of 25,000 K on a 100 ps time scale. At shock coalescence, the scattering spectra show the collective plasmon oscillations indicating the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of three thereby reaching conditions in the laboratory important for studying astrophysics phenomena.

  7. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source.

    PubMed

    Fletcher, L B; Zastrau, U; Galtier, E; Gamboa, E J; Goede, S; Schumaker, W; Ravasio, A; Gauthier, M; MacDonald, M J; Chen, Z; Granados, E; Lee, H J; Fry, A; Kim, J B; Roedel, C; Mishra, R; Pelka, A; Kraus, D; Barbrel, B; Döppner, T; Glenzer, S H

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  8. High resolution x-ray Thomson scattering measurements from cryogenic hydrogen jets using the linac coherent light source

    NASA Astrophysics Data System (ADS)

    Fletcher, L. B.; Zastrau, U.; Galtier, E.; Gamboa, E. J.; Goede, S.; Schumaker, W.; Ravasio, A.; Gauthier, M.; MacDonald, M. J.; Chen, Z.; Granados, E.; Lee, H. J.; Fry, A.; Kim, J. B.; Roedel, C.; Mishra, R.; Pelka, A.; Kraus, D.; Barbrel, B.; Döppner, T.; Glenzer, S. H.

    2016-11-01

    We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].

  9. Suppression of spurious mode oscillation in mega-watt 77-GHz gyrotron as a high quality probe beam source for the collective Thomson scattering in LHD

    SciTech Connect

    Ogasawara, S.; Kubo, S.; Nishiura, M.; Tanaka, K.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Ito, S.; Takita, Y.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Tatematsu, Y.; Saito, T.; Minami, R.; Kariya, T.; Imai, T.

    2012-10-15

    Collective Thomson scattering (CTS) diagnostic requires a strong probing beam to diagnose a bulk and fast ion distribution function in fusion plasmas. A mega-watt gyrotron for electron cyclotron resonance heating is used as a probing beam in the large helical device. Spurious mode oscillations are often observed during the turning on/off phase of the modulation. The frequency spectra of the 77-GHz gyrotron output power have been measured, and then one of the spurious modes, which interferes with the CTS receiver system, is identified as the TE{sub 17,6} mode at the frequency of 74.7 GHz. The mode competition calculation indicates that the increase of the magnetic field strength at the gyrotron resonator can avoid such a spurious mode and excite only the main TE{sub 18,6} mode. The spurious radiation at the 74.7 GHz is experimentally demonstrated to be suppressed in the stronger magnetic field than that optimized for the high-power operation.

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

    PubMed

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

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  11. Comparison of multialkali and GaAs photocathode detectors for Joint European Torus edge light detection and ranging Thomson scattering profiles

    NASA Astrophysics Data System (ADS)

    Kempenaars, M.; Nielsen, P.; Pasqualotto, R.; Gowers, C.; Beurskens, M.

    2004-10-01

    The Joint European Torus (JET) tokamak has two light detection and ranging (LIDAR) Thomson scattering systems, one for the core and one dedicated to the edge Te and ne profiles. The LIDAR scheme is unique to JET and is envisaged for use on ITER. The system's spatial resolution is defined by the convolution product of its components: laser pulse duration, detector response time, and digitizer speed. The original multialkali photocathode microchannel plate photomultipliers dictated the response time, resulting in a 12 cm spatial resolution along the line of sight. In the edge LIDAR system, this is improved by aligning the line of sight with the flux surfaces, thus improving the effective spatial resolution to 2 cm depending on the plasma configuration. To meet demands for better edge gradient resolution, an upgrade to higher quantum efficiency detectors was proposed. Four GaAs photocathode detectors have been procured, two of which surpass expectations. These detectors are shown to have a more than two times higher effective quantum efficiency and their response time is at least twice as fast as the multialkali detectors. Combined with a fast digitizer this improves the spatial resolution by a factor of two, down to one centimeter effective, depending on plasma configuration.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.

  13. Comparison of multialkali and GaAs photocathode detectors for Joint European Torus edge light detection and ranging Thomson scattering profiles

    SciTech Connect

    Kempenaars, M.; Nielsen, P.; Pasqualotto, R.; Gowers, C.; Beurskens, M.

    2004-10-01

    The Joint European Torus (JET) tokamak has two light detection and ranging (LIDAR) Thomson scattering systems, one for the core and one dedicated to the edge T{sub e} and n{sub e} profiles. The LIDAR scheme is unique to JET and is envisaged for use on ITER. The system's spatial resolution is defined by the convolution product of its components: laser pulse duration, detector response time, and digitizer speed. The original multialkali photocathode microchannel plate photomultipliers dictated the response time, resulting in a 12 cm spatial resolution along the line of sight. In the edge LIDAR system, this is improved by aligning the line of sight with the flux surfaces, thus improving the effective spatial resolution to 2 cm depending on the plasma configuration. To meet demands for better edge gradient resolution, an upgrade to higher quantum efficiency detectors was proposed. Four GaAs photocathode detectors have been procured, two of which surpass expectations. These detectors are shown to have a more than two times higher effective quantum efficiency and their response time is at least twice as fast as the multialkali detectors. Combined with a fast digitizer this improves the spatial resolution by a factor of two, down to one centimeter effective, depending on plasma configuration.

  14. Phase space distribution of an electron beam emerging from Compton/Thomson back-scattering by an intense laser pulse

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Chaikovska, I.; Ronsivalle, C.; Rossi, A. R.; Serafini, L.; Vaccarezza, C.

    2013-01-01

    We analyze the energy distribution of a relativistic electron beam after the Compton back-scattering by a counterpropagating laser field. The analysis is performed for parameters in the range of realistic X-γ sources, in the framework of the Quantum Electrodynamics, by means of the code CAIN. The results lead to the conclusion that, in the regime considered, the main effect is the initial formation of stripes, followed by the diffusion of the most energetic particles toward lower values in the longitudinal phase space, with a final increase of the electron energy bandwidth.

  15. Edge profile analysis of Joint European Torus (JET) Thomson scattering data: Quantifying the systematic error due to edge localised mode synchronisation.

    PubMed

    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.

  16. Design of practical alignment device in KSTAR Thomson diagnostic

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Lee, S. H.; Yamada, I.

    2016-11-01

    The precise alignment of the laser path and collection optics in Thomson scattering measurements is essential for accurately determining electron temperature and density in tokamak experiments. For the last five years, during the development stage, the KSTAR tokamak's Thomson diagnostic system has had alignment fibers installed in its optical collection modules, but these lacked a proper alignment detection system. In order to address these difficulties, an alignment verifying detection device between lasers and an object field of collection optics is developed. The alignment detection device utilizes two types of filters: a narrow laser band wavelength for laser, and a broad wavelength filter for Thomson scattering signal. Four such alignment detection devices have been successfully developed for the KSTAR Thomson scattering system in this year, and these will be tested in KSTAR experiments in 2016. In this paper, we present the newly developed alignment detection device for KSTAR's Thomson scattering diagnostics.

  17. Injectors for Multipoint Injection

    NASA Technical Reports Server (NTRS)

    Prociw, Lev Alexander (Inventor); Ryon, Jason (Inventor)

    2015-01-01

    An injector for a multipoint combustor system includes an inner air swirler which defines an interior flow passage and a plurality of swirler inlet ports in an upstream portion thereof. The inlet ports are configured and adapted to impart swirl on flow in the interior flow passage. An outer air cap is mounted outboard of the inner swirler. A fuel passage is defined between the inner air swirler and the outer air cap, and includes a discharge outlet between downstream portions of the inner air swirler and the outer air cap for issuing fuel for combustion. The outer air cap defines an outer air circuit configured for substantially unswirled injection of compressor discharge air outboard of the interior flow passage.

  18. NASA Multipoint LDI Development

    NASA Technical Reports Server (NTRS)

    Tacina, Robert

    2001-01-01

    Multipoint Lean-Direct-Injection (LDI) is a combustor concept in which a large number of fuel injectors and fuel-air mixers are used to quickly and uniformly mix the fuel and air so that ultralow levels of NO, are produced. Each fuel injector has an air swirler associated with it for fuel-air mixing and to establish a small recirculation and burning zone. A concept in which there are 36 fuel injectors in the space of a conventional single fuel injector has been tested in a flame tube. A greater than 80 percent reduction in NO, at high power conditions (400 psia, 1000 "Finlet) was achieved. Alternate concepts with 9,25,36 or 49 fuel injectors are being investigated in flame tube tests for their low NO, potential and with fuel staging to improve the turn-down ratio at low power conditions. A preliminary sector concept of a large engine design has been successfully tested at inlet conditions of 700 psia and 1100 O F . This concept had one half the number of fuel injectors per square inch as the flame tube configuration with 36 fuel injectors, and the NO, reduction was 65 percent of the ICAO standard. Future regional engine size sector tests are planned for the 2nd quarter of FY02 and large engine size sector tests for the 1st quarter of FY03.

  19. 47 CFR 1.824 - Random selection procedures for Multichannel Multipoint Distribution Service and Multipoint...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Multipoint Distribution Service and Multipoint Distribution Service H-Channel stations. 1.824 Section 1.824... for Multichannel Multipoint Distribution Service and Multipoint Distribution Service H-Channel...) or (b)(3) shall be granted to any MMDS or MDS H-channel applicant whose owners, when aggregated,...

  20. 47 CFR 1.824 - Random selection procedures for Multichannel Multipoint Distribution Service and Multipoint...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Multipoint Distribution Service and Multipoint Distribution Service H-Channel stations. 1.824 Section 1.824... for Multichannel Multipoint Distribution Service and Multipoint Distribution Service H-Channel...) or (b)(3) shall be granted to any MMDS or MDS H-channel applicant whose owners, when aggregated,...

  1. Dual color x-rays from Thomson or Compton sources

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2015-05-01

    We analyze the possibility of producing two color X or γ radiation by Thomson/Compton back-scattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of values for a realistic experiments.

  2. Joule Thomson refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, Chung K. (Inventor); Gatewood, John R. (Inventor)

    1988-01-01

    A bi-directional Joule Thomson refrigerator is described, which is of simple construction at the cold end of the refrigerator. Compressed gas flowing in either direction through the Joule Thomson expander valve and becoming liquid, is captured in a container in direct continuous contact with the heat load. The Joule Thomson valve is responsive to the temperature of the working fluid near the valve, to vary the flow resistance through the valve so as to maintain a generally constant flow mass between the time that the refrigerator is first turned on and the fluid is warm, and the time when the refrigerator is near its coldest temperature and the fluid is cold. The valve is operated by differences in thermal coefficients of expansion of materials to squeeze and release a small tube which acts as the expander valve.

  3. The SPARC_LAB Thomson source

    NASA Astrophysics Data System (ADS)

    Vaccarezza, C.; Alesini, D.; Anania, M. P.; Bacci, A.; Biagioni, A.; Bisesto, F.; Bellaveglia, M.; Cardarelli, P.; Cardelli, F.; Cianchi, A.; Chiadroni, E.; Croia, M.; Curcio, A.; Delogu, P.; Giovenale, D. Di; Domenico, G. Di; Pirro, G. Di; Drebot, I.; Ferrario, M.; Filippi, F.; Gallo, A.; Galletti, M.; Gambaccini, M.; Giribono, A.; Golosio, B.; Li, W.; Mostacci, A.; Oliva, P.; Palmer, D.; Petrillo, V.; Petrarca, M.; Pioli, S.; Piersanti, L.; Pompili, R.; Romeo, S.; Rossi, A. R.; Scifo, J.; Serafini, L.; Suliman, G.; Villa, F.

    2016-09-01

    The SPARC_LAB Thomson source is a compact X-ray source based on the Thomson backscattering process presently under its second phase of commissioning at the LNF. The electron beam energy ranges between 30 and 150 MeV, the electrons collide head-on with the Ti:Sapphire FLAME laser pulse the energy of which ranges between 1 and 5 J with pulse lengths in the 25 fs-10 ps range, this provides an X-ray energy tunability in the range of 20-500 keV, with the further capability to generate strongly non-linear phenomena and to drive diffusion processes due to multiple and plural scattering effects. The experimental results of the obtained X-ray radiation are presented.

  4. Multipoint sensing by intelligent collectives

    NASA Technical Reports Server (NTRS)

    Clare, L. P.

    2002-01-01

    Many remote sensing applications require that multiple sensors collect data simultaneously at spatially distributed locations and their information combined in order to characterize the phenomena of interest. Several basic classes of such multipoint measurement systems may be identified. For each, centralized methods exist for combining the raw data from the various sensors. However, recent advancements have given rise to small, integrated nodes comprised of one or more miniaturized sensors, processor, wireless communications capability and power supplies. Collections of these may be deployed and self-organized into intelligent sensor networks capable of performing cooperative signal processing locally, thereby providing substantial benefits.

  5. Cycling Joule Thomson refrigerator

    NASA Technical Reports Server (NTRS)

    Tward, E. (Inventor)

    1983-01-01

    A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

  6. Multipoint study of interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Blanco-Cano, Xochitl; Kajdic, Primoz; Russell, Christopher T.; Aguilar-Rodriguez, Ernesto; Jian, Lan K.; Luhmann, Janet G.

    2016-04-01

    Interplanetary (IP) shocks are driven in the heliosphere by Interplanetary Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs). These shocks perturb the solar wind plasma, and play an active role in the acceleration of ions to suprathermal energies. Shock fronts evolve as they move from the Sun. Their surfaces can be far from uniform and be modulated by changes in the ambient solar wind (magnetic field orientation, flow velocity), shocks rippling, and perturbations upstream and downstream from the shocks, i.e., electromagnetic waves. In this work we use multipoint observations from STEREO, WIND, and MESSENGER missions to study shock characteristics at different helio-longitudes and determine the properties of the waves near them. We also determine shock longitudinal extensions and foreshock sizes. The variations of geometry along the shock surface can result in different extensions of the wave and ion foreshocks ahead of the shocks, and in different wave modes upstream and downtream of the shocks. We find that the ion foreshock can extend up to 0.2 AU ahead of the shock, and that the upstream region with modified solar wind/waves can be very asymmetric.

  7. EDITORIAL: J J Thomson's Electron

    NASA Astrophysics Data System (ADS)

    Adams, Steve

    1997-07-01

    Westminster School, London, UK A few weeks ago David Thomson, J J Thomson's grandson, presented a Friday evening discourse at the Royal Institution. In it he traced the development of JJT's life from his early studies at Owen's College in Manchester, on to Trinity College Cambridge, his work under Rayleigh at the Cavendish, and his succession as Professor of Experimental Physics in 1884 (a post he passed on to Rutherford in 1919). These were years of heroic discoveries that shaped 20th century physics. Looking around the lecture theatre at all the bow-ties and dinner jackets, it must have been rather similar on 30 April 1897 when JJT delivered his famous discourse on 'Cathode Rays' in which he cautiously but confidently announced that his own results together with those of other experimenters (Lenard in particular):

    `....seem to favour the hypothesis that the carriers of the charges are smaller than the atoms of hydrogen.'
    In this issue articles by Leif Gerward and Christopher Cousins, and by Isobel Falconer explore the historical and philosophical context of that discovery. The sound-bites to history in many A-level courses have JJT as both the hero who single-handedly discovered the electron and the rather naive Victorian scientist who thought the atom was a plum pudding. It is valuable to see how Thomson's work pulled the threads of many experiments together and to realize that he may have been first to the post because of a difference in the philosophical approach to cathode rays in Britain compared to Europe. Experimental data must always be interpreted, and divergent philosophies can lead to quite different conclusions. The electron was, of course, the first subatomic particle to be identified. Christine Sutton's article looks at how 20th century discoveries reveal Nature's mysterious habit of repeating successful patterns---electrons for example have very close relations, the muon and the tau---but why? Perhaps the answer will come

  8. 76 FR 27365 - West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration West, A Thomson Reuters Business, Thomson Reuters Legal Division... former workers of West, A Thomson Reuters Business, Thomson Reuters Legal Division, Albuquerque,...

  9. Sub-Picosecond, High Flux, Thomson X-Ray Sources

    SciTech Connect

    James Boyce; David Douglas; Hiroyuki Toyokawa; Winthrop J. Brown; Fred Hartemann

    2003-05-12

    With the advent of high average power FELs, the idea of using such a device to produce x-rays via the Thomson scattering process is appealing, if sufficient flux and/or brightness can be generated. Such x-rays are produced simultaneously with FEL light, offering unprecedented opportunities for pump-probe studies. We discuss non-invasive modifications to the Jefferson Lab's FEL that would meet the criteria of high flux, sub-picosecond, x-ray source. One allows proof-of-principle experiments, is relatively inexpensive, but is not conducive as a ''User-facility.'' Another is a User facility configuration but requires FEL facility modifications. For all sources, we present Thomson scattering flux calculations and potential applications.

  10. A compact multichannel spectrometer for Thomson scatteringa)

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  11. Rothmund-Thomson syndrome

    PubMed Central

    2010-01-01

    Rothmund-Thomson syndrome (RTS) is a genodermatosis presenting with a characteristic facial rash (poikiloderma) associated with short stature, sparse scalp hair, sparse or absent eyelashes and/or eyebrows, juvenile cataracts, skeletal abnormalities, radial ray defects, premature aging and a predisposition to cancer. The prevalence is unknown but around 300 cases have been reported in the literature so far. The diagnostic hallmark is facial erythema, which spreads to the extremities but spares the trunk, and which manifests itself within the first year and then develops into poikiloderma. Two clinical subforms of RTS have been defined: RTSI characterised by poikiloderma, ectodermal dysplasia and juvenile cataracts, and RTSII characterised by poikiloderma, congenital bone defects and an increased risk of osteosarcoma in childhood and skin cancer later in life. The skeletal abnormalities may be overt (frontal bossing, saddle nose and congenital radial ray defects), and/or subtle (visible only by radiographic analysis). Gastrointestinal, respiratory and haematological signs have been reported in a few patients. RTS is transmitted in an autosomal recessive manner and is genetically heterogeneous: RTSII is caused by homozygous or compound heterozygous mutations in the RECQL4 helicase gene (detected in 60-65% of RTS patients), whereas the aetiology in RTSI remains unknown. Diagnosis is based on clinical findings (primarily on the age of onset, spreading and appearance of the poikiloderma) and molecular analysis for RECQL4 mutations. Missense mutations are rare, while frameshift, nonsense mutations and splice-site mutations prevail. A fully informative test requires transcript analysis not to overlook intronic deletions causing missplicing. The diagnosis of RTS should be considered in all patients with osteosarcoma, particularly if associated with skin changes. The differential diagnosis should include other causes of childhood poikiloderma (including dyskeratosis

  12. 76 FR 50272 - West, A Thomson Reuters Business, Thomson Reuters Legal Division, Including On-Site Leased...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... Employment and Training Administration West, A Thomson Reuters Business, Thomson Reuters Legal Division... Reuters Business, Thomson Reuters Legal Division, including On-Site Leased Workers from Adecco... applicable to workers and former workers of West, A Thomson Reuters Business, Thomson Reuters...

  13. Inverse Gibbs-Thomson effect

    NASA Astrophysics Data System (ADS)

    Gershanov, V. Yu.; Garmashov, S. I.

    2015-01-01

    We prove the existence of an effect inverse to the Gibbs-Thomson effect for mass transfer in systems consisting of a solid phase and the solution of the solid phase material in a certain solvent. The effect involves a change in the shape of the interface due to a variation of the equilibrium concentrations under it, which is induced by external conditions, and exists in the presence of a negative feedback for mass transfer associated with capillary effects.

  14. Multi-Point Combustion System: Final Report

    NASA Technical Reports Server (NTRS)

    Goeke, Jerry; Pack, Spencer; Zink, Gregory; Ryon, Jason

    2014-01-01

    A low-NOx emission combustor concept has been developed for NASA's Environmentally Responsible Aircraft (ERA) program to meet N+2 emissions goals for a 70,000 lb thrust engine application. These goals include 75 percent reduction of LTO NOx from CAEP6 standards without increasing CO, UHC, or smoke from that of current state of the art. An additional key factor in this work is to improve lean combustion stability over that of previous work performed on similar technology in the early 2000s. The purpose of this paper is to present the final report for the NASA contract. This work included the design, analysis, and test of a multi-point combustion system. All design work was based on the results of Computational Fluid Dynamics modeling with the end results tested on a medium pressure combustion rig at the UC and a medium pressure combustion rig at GRC. The theories behind the designs, results of analysis, and experimental test data will be discussed in this report. The combustion system consists of five radially staged rows of injectors, where ten small scale injectors are used in place of a single traditional nozzle. Major accomplishments of the current work include the design of a Multipoint Lean Direct Injection (MLDI) array and associated air blast and pilot fuel injectors, which is expected to meet or exceed the goal of a 75 percent reduction in LTO NOx from CAEP6 standards. This design incorporates a reduced number of injectors over previous multipoint designs, simplified and lightweight components, and a very compact combustor section. Additional outcomes of the program are validation that the design of these combustion systems can be aided by the use of Computational Fluid Dynamics to predict and reduce emissions. Furthermore, the staging of fuel through the individually controlled radially staged injector rows successfully demonstrated improved low power operability as well as improvements in emissions over previous multipoint designs. Additional comparison

  15. Scalar discrete nonlinear multipoint boundary value problems

    NASA Astrophysics Data System (ADS)

    Rodriguez, Jesus; Taylor, Padraic

    2007-06-01

    In this paper we provide sufficient conditions for the existence of solutions to scalar discrete nonlinear multipoint boundary value problems. By allowing more general boundary conditions and by imposing less restrictions on the nonlinearities, we obtain results that extend previous work in the area of discrete boundary value problems [Debra L. Etheridge, Jesus Rodriguez, Periodic solutions of nonlinear discrete-time systems, Appl. Anal. 62 (1996) 119-137; Debra L. Etheridge, Jesus Rodriguez, Scalar discrete nonlinear two-point boundary value problems, J. Difference Equ. Appl. 4 (1998) 127-144].

  16. Multipoint Green's functions in 1 + 1 dimensional integrable quantum field theories

    NASA Astrophysics Data System (ADS)

    Babujian, H. M.; Karowski, M.; Tsvelik, A. M.

    2017-04-01

    We calculate the multipoint Green's functions in 1+1 dimensional integrable quantum field theories. We use the crossing formula for general models and calculate the 3 and 4 point functions taking in to account only the lower nontrivial intermediate states contributions. Then we apply the general results to the examples of the scaling Z2 Ising model, sinh-Gordon model and Z3 scaling Potts model. We demonstrate this calculations explicitly. The results can be applied to physical phenomena as for example to the Raman scattering.

  17. Multipoint free-space optics system for short-range communications between flight platforms.

    PubMed

    Heng, Kiang Huat; Zhong, Wen-De; Cheng, Tee Hiang

    2010-01-10

    The problems associated with using typical free-space optics (FSO) transceivers for multipoint communications on flight platforms, such as satellites and unmanned aerial vehicles, in a cluster are discussed and the transceivers are found to be unsuitable for concurrent multipoint communications in those platforms. To overcome the problems, a multipoint FSO system design is proposed. The design of the multipoint system is described and the performance of the multipoint receiver is evaluated in terms of receive gain under different conditions. The proposed multipoint system design offers a promising way to implement concurrent multipoint communications on flight platforms with power, weight, and size advantages compared to the use of multiple transceivers.

  18. Multipoint observations of a small substorm

    NASA Technical Reports Server (NTRS)

    Lopez, R. E.; Anderson, B. J.; Newell, P. T.; Mcentire, R. W.; Luehr, H.

    1990-01-01

    Results are presented of multipoint observations of a small substorm which occurred at about 0110 UT on April 25, 1985, carried out by AMPTE CCE, AMPTE IRM, DMSP F6, and DMSP F7, as well as by ground auroral stations and midlatitude stations. These data yield information on the latitudinal extent of the polar cap and provide visual identification of substorm aurorae, magnetic perturbations produced directly beneath aurorae, and the situ magnetic field. In addition, they provide magnetic-particle observations of the disruption of the cross-tail current sheet and observations concerning the spatial expansion of the current disruption region. Evidence is presented that the current sheet disruption observed by CCE in the neutral sheet was located on field lines which mapped to the westward traveling surge observed directly overhead of the ground station at Syowa.

  19. Deriving CME kinematics from multipoint space observations

    NASA Astrophysics Data System (ADS)

    Mrotzek, Niclas; Pluta, Adam; Bothmer, Volker; Davies, Jackie; Harrison, Richard

    2016-04-01

    It is commonly believed that the kinematics of CMEs consist of an early Lorentz acceleration phase near the Sun followed by a decelerating drag-force phase at distances further out. To better understand the physical processes of CME evolution, and also to predict more accurately their arrival times at other heliospheric locations, we have analysed CMEs using multipoint coronagraph observations from STEREO and SOHO. The CME speed evolution is analysed by applying time-series GCS-modelling. The analysis is extended to distances further away from the Sun through analysis of observations from the STEREO heliospheric imagers. The results are compared to those obtained from the geometrical modelling of time-elongation profiles of CMEs extracted from J-maps. We discuss the implications of our results in the context of state-of-the-art space weather predictions. The studies are carried out in the EU FP7 project HELCATS (Heliospheric Cataloguing, Analysis and Techniques Service).

  20. Multi-point laser ignition device

    DOEpatents

    McIntyre, Dustin L.; Woodruff, Steven D.

    2017-01-17

    A multi-point laser device comprising a plurality of optical pumping sources. Each optical pumping source is configured to create pumping excitation energy along a corresponding optical path directed through a high-reflectivity mirror and into substantially different locations within the laser media thereby producing atomic optical emissions at substantially different locations within the laser media and directed along a corresponding optical path of the optical pumping source. An output coupler and one or more output lenses are configured to produce a plurality of lasing events at substantially different times, locations or a combination thereof from the multiple atomic optical emissions produced at substantially different locations within the laser media. The laser media is a single continuous media, preferably grown on a single substrate.

  1. Cascade Joule-Thomson refrigerators

    NASA Technical Reports Server (NTRS)

    Tward, E.; Steyert, W. A.

    1983-01-01

    The design criteria for cascade Joule-Thomson refrigerators for cooling in the temperature range from 300 K to 4.2 K were studied. The systems considered use three or four refrigeration stages with various working gases to achieve the low temperatures. Each stage results in cooling to a progressively lower temperature and provides cooling at intermediate temperatures to remove the substantial amount of parasitic heat load encountered in a typical dewar. With careful dewar design considerable cooling can be achieved with moderate gas flows. For many applications, e.g., in the cooling of sensitive sensors, the fact that the refrigerator contains no moving parts and may be remotely located from the gas source is of considerable advantage. A small compressor suitable for providing the gas flows required was constructed.

  2. Narrowband Emission in Compton/Thomson Sources Operating in the High-Field Regime

    SciTech Connect

    Terzic, Balsa; Deitrick, Kirsten E.; Hofler, Alicia S.; Kraff, Geoffrey A.

    2014-02-21

    We present a novel and quite general analysis of the interaction of a high-field chirped laser pulse and a relativistic electron, in which exquisite control of the spectral brilliance of the upshifted Thomson-scattered photon is shown to be possible. Normally, when Thomson scattering occurs at high field strengths, there is ponderomotive line broadening in the scattered radiation. This effect makes the bandwidth too large for some applications, and reduces the spectral brilliance. In this paper we show that such broadening can be corrected and eliminated by suitable frequency modulation of the incident laser pulse. Further, we suggest a practical realization of this compensation idea in terms of a chirped-beam driven FEL oscillator configuration, and show that significant compensation can occur, even with the imperfect matching to be expected in these conditions.

  3. Narrowband Emission in Compton/Thomson Sources Operating in the High-Field Regime

    DOE PAGES

    Terzic, Balsa; Deitrick, Kirsten E.; Hofler, Alicia S.; ...

    2014-02-21

    We present a novel and quite general analysis of the interaction of a high-field chirped laser pulse and a relativistic electron, in which exquisite control of the spectral brilliance of the upshifted Thomson-scattered photon is shown to be possible. Normally, when Thomson scattering occurs at high field strengths, there is ponderomotive line broadening in the scattered radiation. This effect makes the bandwidth too large for some applications, and reduces the spectral brilliance. In this paper we show that such broadening can be corrected and eliminated by suitable frequency modulation of the incident laser pulse. Further, we suggest a practical realizationmore » of this compensation idea in terms of a chirped-beam driven FEL oscillator configuration, and show that significant compensation can occur, even with the imperfect matching to be expected in these conditions.« less

  4. Joule-Thomson expander and heat exchanger

    NASA Technical Reports Server (NTRS)

    Norman, R. H.

    1976-01-01

    The Joule-Thomson Expander and Heat Exchanger Program was initiated to develop an assembly (JTX) which consists of an inlet filter, counterflow heat exchanger, Joule-Thomson expansion device, and a low pressure jacket. The program objective was to develop a JTX which, when coupled to an open cycle supercritical helium refrigerating system (storage vessel), would supply superfluid helium (He II) at 2 K or less for cooling infrared detectors.

  5. Multipoint quantitative-trait linkage analysis in general pedigrees.

    PubMed Central

    Almasy, L; Blangero, J

    1998-01-01

    Multipoint linkage analysis of quantitative-trait loci (QTLs) has previously been restricted to sibships and small pedigrees. In this article, we show how variance-component linkage methods can be used in pedigrees of arbitrary size and complexity, and we develop a general framework for multipoint identity-by-descent (IBD) probability calculations. We extend the sib-pair multipoint mapping approach of Fulker et al. to general relative pairs. This multipoint IBD method uses the proportion of alleles shared identical by descent at genotyped loci to estimate IBD sharing at arbitrary points along a chromosome for each relative pair. We have derived correlations in IBD sharing as a function of chromosomal distance for relative pairs in general pedigrees and provide a simple framework whereby these correlations can be easily obtained for any relative pair related by a single line of descent or by multiple independent lines of descent. Once calculated, the multipoint relative-pair IBDs can be utilized in variance-component linkage analysis, which considers the likelihood of the entire pedigree jointly. Examples are given that use simulated data, demonstrating both the accuracy of QTL localization and the increase in power provided by multipoint analysis with 5-, 10-, and 20-cM marker maps. The general pedigree variance component and IBD estimation methods have been implemented in the SOLAR (Sequential Oligogenic Linkage Analysis Routines) computer package. PMID:9545414

  6. Service architecture for coordinating multipoint multimedia communications

    NASA Astrophysics Data System (ADS)

    Machida, Shuichi; Koga, Yuzo; Miyamoto, Shinro; Morikawa, Yusuki; Shigeno, Hiroshi; Matsushita, Yutaka

    2001-11-01

    In this paper, we propose a service architecture that enables end users to establish multipoint multimedia communications without being conscious of one another's networking environment. The proposed architecture is composed of three conceptual models based on RM-ODP(Reference Model of Open Distributed Processing), those are concerned with enterprise, information and computational viewpoint, respectively. From the enterprise viewpoint, the Session Coordinator Role is introduced, which manages connections among end users in consideration of their terminal devices' capabilities. Furthermore, the Content Provider and Content Consumer Role, which respectively play the role of providing and consuming a multimedia content, are also introduced to represent these capabilities. These roles are embodied as service components from the computational viewpoint. From the information viewpoint, two concepts, session and content flow, are introduced to facilitate unified management of various multimedia communications. The concept, continuous session mobility, is also the key idea of the architecture. This enables end users to move around participating in a multimedia conferencing independently of their networking environments. We show the concrete model of realizing it by implementing a prototype system based on the architecture.

  7. Multipoint sensor based on fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Méndez-Zepeda, O.; Muñoz-Aguirre, S.; Beltrán-Pérez, G.; Castillo-Mixcóatl, J.

    2011-01-01

    In some control and industrial measurement systems of physical variables (pressure, temperature, flow, etc) it is necessary one system and one sensor to control each process. On the other hand, there are systems such as PLC (Programmable Logic Control), which can process several signals simultaneously. However it is still necessary to use one sensor for each variable. Therefore, in the present work the use of a multipoint sensor to solve such problem has been proposed. The sensor consists of an optical fiber laser with two Fabry-Perot cavities constructed using fiber Bragg gratings (FBG). In the same system is possible to measure changes in two variables by detecting the intermodal separation frequency of each cavity and evaluate their amplitudes. The intermodal separation frequency depends on each cavity length. The sensor signals are monitored through an oscilloscope or a PCI card and after that acquired by PC, where they are analyzed and displayed. Results of the evaluation of the intermodal frequency separation peak amplitude behavior with FBG stretching are presented.

  8. Reliable Wireless Broadcast with Linear Network Coding for Multipoint-to-Multipoint Real-Time Communications

    NASA Astrophysics Data System (ADS)

    Kondo, Yoshihisa; Yomo, Hiroyuki; Yamaguchi, Shinji; Davis, Peter; Miura, Ryu; Obana, Sadao; Sampei, Seiichi

    This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for ad-hoc networks like video game networks. We aim to achieve highly reliable MPtoMP broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the encoded packet is broadcasted in the next sequence as a piggy-back for its native packet. To prevent increase of overhead in each packet due to piggy-back packet transmission, network coding vector for each node is exchanged between all nodes in the negotiation phase. Each user keeps using the same coding vector generated in the negotiation phase, and only coding information that represents which user signal is included in the network coding process is transmitted along with the piggy-back packet. Our simulation results show that the proposed method can provide higher reliability than other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with a practical degree of complexity when installed on current wireless devices.

  9. An analytic formula for the relativistic incoherent Thomson backscattering spectrum for a drifting bi-Maxwellian plasma

    SciTech Connect

    Naito, O.

    2015-08-15

    An analytic formula has been derived for the relativistic incoherent Thomson backscattering spectrum for a drifting anisotropic plasma when the scattering vector is parallel to the drifting direction. The shape of the scattering spectrum is insensitive to the electron temperature perpendicular to the scattering vector, but its amplitude may be modulated. As a result, while the measured temperature correctly represents the electron distribution parallel to the scattering vector, the electron density may be underestimated when the perpendicular temperature is higher than the parallel temperature. Since the scattering spectrum in shorter wavelengths is greatly enhanced by the existence of drift, the diagnostics might be used to measure local electron current density in fusion plasmas.

  10. Multipoint contact modeling of nanoparticle manipulation on rough surface

    NASA Astrophysics Data System (ADS)

    Zakeri, M.; Faraji, J.; Kharazmi, M.

    2016-12-01

    In this paper, the atomic force microscopy (AFM)-based 2-D pushing of nano/microparticles investigated on rough substrate by assuming a multipoint contact model. First, a new contact model was extracted and presented based on the geometrical profiles of Rumpf, Rabinovich and George models and the contact mechanics theories of JKR and Schwartz, to model the adhesion forces and the deformations in the multipoint contact of rough surfaces. The geometry of a rough surface was defined by two main parameters of asperity height (size of roughness) and asperity wavelength (compactness of asperities distribution). Then, the dynamic behaviors of nano/microparticles with radiuses in range of 50-500 nm studied during their pushing on rough substrate with a hexagonal or square arrangement of asperities. Dynamic behavior of particles were simulated and compared by assuming multipoint and single-point contact schemes. The simulation results show that the assumption of multipoint contact has a considerable influence on determining the critical manipulation force. Additionally, the assumption of smooth surfaces or single-point contact leads to large error in the obtained results. According to the results of previous research, it anticipated that a particles with the radius less than about 550 nm start to slide on smooth substrate; but by using multipoint contact model, the predicted behavior changed, and particles with radii of smaller than 400 nm begin to slide on rough substrate for different height of asperities, at first.

  11. Multipoint observations of a small substorm

    SciTech Connect

    Lopez, R.E. Applied Research Corp., Landover, MD ); Luehr, H. ); Anderson, B.J.; Newell, P.T.; McEntire, R.W. )

    1990-11-01

    In this paper the authors present multipoint observations of a small substorm which occurred just after 0110 UT on April 25, 1985. The observations were made by spacecraft (AMPTE CCE, AMPTE IRM, DMSP F6, and DMSP F7), ground auroral stations (EISCAT magnetometer cross, Syowa, Narssarssuaq, Great Whale River, and Fort Churchill), and mid-latitude stations (Furstenfeldbruck, Toledo, and Argentine Island). These data provide them with a broad range of observations, including the latitudinal extent of the polar cap, visual identification of substorm aurorae and the magnetic perturbations produced directly beneath them, in situ magnetic field and energetic particle observations of the disruption of the cross-tail current sheet, and observations concerning the spatial expansion of the current disruption region from two radially aligned spacecraft. The DMSP data indicate that the event took place during a period when the polar cap was relatively contracted, yet the disruption of the current sheet was observed by CCE at 8.56 R{sub E}. They have been able to infer a considerable amount of detail concerning the structure and westward expansion of the auroral features associated with the event, and they show that those auroral surges were located more than 10{degree} equatorward of the boundary between open and closed field lines. Moreover, they present evidence that the current sheet disruption observed by CCE in the neutral sheet was located on field lines which mapped to the westward traveling surge observed directly overhead of the ground station at Syowa. Furthermore, the observations strongly imply that disruption of the cross-tail current began in the near-Earth region and that it had a component of expansion which was radially antisunward.

  12. 76 FR 45879 - West, a Thomson Reuters Business, Thomson Reuters Legal, Including On-Site Leased Workers From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

    ... Employment and Training Administration West, a Thomson Reuters Business, Thomson Reuters Legal, Including On... June 21, 2010, applicable to workers of West, A Thomson Reuters Legal, including on-site leased workers... occurred involving a teleworker (Robert Louie) located in Albuquerque, New Mexico who reported to...

  13. Convergence of multipoint Pade approximants of piecewise analytic functions

    SciTech Connect

    Buslaev, Viktor I

    2013-02-28

    The behaviour as n{yields}{infinity} of multipoint Pade approximants to a function which is (piecewise) holomorphic on a union of finitely many continua is investigated. The convergence of multipoint Pade approximants is proved for a function which extends holomorphically from these continua to a union of domains whose boundaries have a certain symmetry property. An analogue of Stahl's theorem is established for two-point Pade approximants to a pair of functions, either of which is a multivalued analytic function with finitely many branch points. Bibliography: 11 titles.

  14. The AC Repulsion Demonstration of Elihu Thomson.

    ERIC Educational Resources Information Center

    Quinton, Arthur R.

    1979-01-01

    Traces the early history of an experiment, the launching of a copper or aluminum ring above the pole of an alternating current magnet at switch-on, that was conducted by Elihu Thomson in the last century and presents a simple qualitative explanation of the effect involved. (GA)

  15. Multipoint viscosity measurements in microfluidic channels using optical tweezers.

    PubMed

    Keen, Stephen; Yao, Alison; Leach, Jonathan; Di Leonardo, Roberto; Saunter, Chris; Love, Gordon; Cooper, Jonathan; Padgett, Miles

    2009-07-21

    We demonstrate the technique of multipoint viscosity measurements incorporating the accurate calibration of micron sized particles. We describe the use of a high-speed camera to measure the residual motion of particles trapped in holographic optical tweezers, enabling us to calculate the fluid viscosity at multiple points across the field-of-view of the microscope within a microfluidic system.

  16. Parametric and nonparametric linkage analysis: A unified multipoint approach

    SciTech Connect

    Kruglyak, L.; Daly, M.J.; Reeve-Daly, M.P.; Lander, E.S.

    1996-06-01

    In complex disease studies, it is crucial to perform multipoint linkage analysis with many markers and to use robust nonparametric methods that take account of all pedigree information. Currently available methods fall short in both regards. In this paper, we describe how to extract complete multipoint inheritance information from general pedigrees of moderate size. This information is captured in the multipoint inheritance distribution, which provides a framework for a unified approach to both parametric and nonparametric methods of linkage analysis. Specifically, the approach includes the following: (1) Rapid exact computation of multipoint LOD scores involving dozens of highly polymorphic markers, even in the presence of loops and missing data. (2) Nonparametric linkage (NPL) analysis, a powerful new approach to pedigree analysis. We show that NPL is robust to uncertainty about mode of inheritance, is much more powerful than commonly used nonparametric methods, and loses little power relative to parametric linkage analysis. NPL thus appears to be the method of choice for pedigree studies of complex traits. (3) Information-content mapping, which measures the fraction of the total inheritance information extracted by the available marker data and points out the regions in which typing additional markers is most useful. (4) Maximum-likelihood reconstruction of many-marker haplotypes, even in pedigrees with missing data. We have implemented NPL analysis, LOD-score computation, information-content mapping, and haplotype reconstruction in a new computer package, GENEHUNTER. The package allows efficient multipoint analysis of pedigree data to be performed rapidly in a single user-friendly environment. 34 refs., 9 figs., 2 tabs.

  17. A study of satellite communication network architectures providing multipoint-to-multipoint connection

    NASA Astrophysics Data System (ADS)

    Ohata, K.

    2002-01-01

    multicasting are currently being sought. Satellite networks can efficiently handle various types of connections because each earth station can directly access all of the satellite network traffic. A multipoint to multipoint (M to N) connection is one such example. Satellite networks consume only M+N network resources, while terrestrial networks basically consume MxN network resources. In the past, there has been little demand for the M-to-N connection type; however, Internet technology is changing this situation. Take for example the case of a network for contents distribution network (CDN) service operators. CDN service operators distribute contents from content providers to caching servers deployed on major Internet service provider (ISP) backbone networks throughout the Internet. Here, a satellite network is the most suitable means of CDN, because both multicasting and M-to-N connection functions are required. However, few satellite systems can handle this type of connection properly. are well accepted as de facto systems for providing high speed Internet access, because they are advantageous in terms of both cost and user terminal size. A DVB VSAT system designed based on a broadcasting network is quite suitable for a network that has a server - client type centralized architecture, but in other cases is not suitable, such as when the network has a de-centralized architecture. In contrast, a network for M-to-N connection can be more efficiently constructed on a de-centralized architecture than on a centralized architecture. already operational. These are candidates for networks that provide efficient M-to-N connection, but their flexibility is a major issue. such as flexible connection, and by nature are suitable for de-centralized networks. In particular, FDMA meshed VSAT systems can be constructed simply, thus ensuring low cost. Also, recently developed technologies can compensate for some drawbacks of the system. The increasing TWTA power on satellites will

  18. Quantum model of the Thomson helium atom

    NASA Astrophysics Data System (ADS)

    Kazaryan, E. M.; Shakhnazaryan, V. A.; Sarkisyan, H. A.; Gusev, A. A.

    2014-03-01

    A quantum model of the Thomson helium atom is considered within the framework of stationary perturbation theory. It is shown that from a formal point of view this problem is similar to that of two-electron states in a parabolic quantum dot. The ground state energy of the quantum Thomson helium atom is estimated on the basis of Heisenberg's uncertainty principle. The ground state energies obtained in the first order of perturbation theory and qualitative estimate provide, respectively, upper and lower estimates of eigenvalues derived by numerically solving the problem for a quantum model. The conditions under which the Kohn theorem holds in this system, when the values of resonance absorption frequencies are independent of the Coulomb interaction between electrons, are discussed.

  19. Joule-Thomson Expander Without Check Valves

    NASA Technical Reports Server (NTRS)

    Chan, C. K.; Gatewood, J. R.

    1989-01-01

    Cooling effected by bidirectional, reciprocating flow of gas. Type of Joule-Thomson (J-T) expander for cryogenic cooling requires no check valves to prevent reverse flow of coolant. More reliable than conventional J-T expander, containing network of check valves, each potential source of failure. Gas flows alternately from left to right and right to left. Heat load cooled by evaporation of liquid from left or right compartment, whichever at lower pressure.

  20. Manganese Nitride Sorption Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Phillips, Wayne M.

    1992-01-01

    Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

  1. J. J. Thomson goes to America.

    PubMed

    Downard, Kevin M

    2009-11-01

    Joseph John (J. J.) Thomson was an accomplished scientist who helped lay the foundations of nuclear physics. A humble man of working class roots, Thomson went on to become one of the most influential physicists of the late 19th century. He is credited with the discovery of the electron, received a Nobel Prize in physics in 1906 for investigations into the conduction of electricity by gases, was knighted in 1908, and served as a Cavendish Professor and Director of the laboratory for over 35 years from 1884. His laboratory attracted some of the world's brightest minds; Francis W. Aston, Niels H. D. Bohr, Hugh L. Callendar, Charles T. R. Wilson, Ernest Rutherford, George F. C. Searle, Geoffrey I. Taylor, and John S. E. Townsend all worked under him. This article recounts J. J. Thomson's visits to North America in 1896, 1903, 1909, and finally 1923. It presents his activities and his personal impressions of the people and society of the U.S.A. and Canada, and the science of atomic physics and chemistry in the late 1800s and early 1900s.

  2. Joule-Thomson Cooler Produces Nearly Constant Temperature

    NASA Technical Reports Server (NTRS)

    Bard, Steven; Wu, Jiunn-Jeng; Trimble, Curtis A.

    1992-01-01

    Improved Joule-Thomson cooler maintains nearly constant temperature. Absolute-pressure relief valve helps stabilize temperature of cold head despite variations in atmospheric pressure. Feedback-controlled electrical heater provides additional stabilization. Demand-flow Joule-Thomson valve requires less nitrogen than fixed-orifice Joule-Thomson valve providing same amount of cooling. Provides stable low temperatures required for operation of such devices as tunable diode lasers in laboratory and balloon-borne instruments detecting contaminants in atmosphere.

  3. 78 FR 8587 - Thomson Reuters, Finance Operations & Technology Division, Including On-Site Leased Workers From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ... Employment and Training Administration Thomson Reuters, Finance Operations & Technology Division, Including... Worker Adjustment Assistance on August 2, 2012, applicable to workers of Thomson Reuters, Finance... that workers of Thomson Reuters, Finance Operations & Technology Division, including on-site...

  4. Multipoint mapping calculations for sperm-typing data

    SciTech Connect

    Lazzeroni, L.C.; Lange, K.; Arnheim, N.; Schmitt, K.

    1994-09-01

    This paper explains how multipoint likelihoods can be computed for sperm-typing data. Experimental errors such as multiple sperm per tube, inadequate amplification, and contamination by exogenous DNA are explicitly taken into account. By limiting the number of sperm theoretically possible per tube to a predetermined maximum and by assuming no chiasma interference, maximum-likelihood estimation can be carried out rapidly using the theory of hidden Markov chains. 14 refs., 2 tabs.

  5. A mathematical formalism for hyperspectral, multipoint plastic scintillation detectors.

    PubMed

    Archambault, Louis; Therriault-Proulx, François; Beddar, Sam; Beaulieu, Luc

    2012-11-07

    The aim of this paper is to generalize and extend the mathematical formalism used with plastic scintillation detectors (PSDs). By doing so, we show the feasibility of multi-point PSD. The new formalism is based on the sole hypothesis that a PSD optical signal is a linear superposition of spectra. Two calibration scenarios were developed. Both involve solving a linear equation of the form Y = XB, but the process and input data depend on the information available on the detector system. Simulations were carried out to validate both scenarios and demonstrate the advantages of the new formalism. In this paper, we prove the following results. (1) Multi-point PSDs are feasible. Simulations have shown that six different spectra could be resolved accurately even in the presence of up to 10% Gaussian noise. (2) The new formalism leads to more precise PSD measurements. (3) By using the condition number of the measurement matrix, the ideal sets of calibration measurements can be identified. (4) By using principal component analysis it was possible to identify the best set of wavelength filters. We have shown through numerical simulations that multi-point detectors are feasible. This has potential for applications such as in vivo dose verification. Furthermore, our new formalism can be used to improve the robustness and ease of use of PSDs.

  6. Integrated Multipoint-Laser Endoscopic Airway Measurements by Transoral Approach

    PubMed Central

    Neitsch, Marie; Horn, Iris-Susanne; Hofer, Mathias; Dietz, Andreas; Fischer, Miloš

    2016-01-01

    Objectives. Optical and technical characteristics usually do not allow objective endoscopic distance measurements. So far no standardized method for endoscopic distance measurement is available. The aim of this study was to evaluate the feasibility and accuracy of transoral airway measurements with a multipoint-laser endoscope. Methods. The semirigid endoscope includes a multipoint laser measurement system that projects 49 laser points (wavelength 639 nm, power < 5 mW) into the optical axis of the endoscopic view. Distances, areas, and depths can be measured in real-time. Transoral endoscopic airway measurements were performed on nine human cadavers, which were correlated with CT measurements. Results. The preliminary experiment showed an optimum distance between the endoscope tip and the object of 5 to 6 cm. There was a mean measurement error of 3.26% ± 2.53%. A Spearman correlation coefficient of 0.95 (p = 0.01) was calculated for the laryngeal measurements and of 0.93 (p < 0.01) for the tracheal measurements compared to the CT. Using the Bland-Altman-Plot, the 95% limits of agreement for the laryngeal measurements were satisfactory: −0.76 and 0.93. Conclusions. Integrated multipoint-laser endoscopic measurement is a promising technical supplement, with potential use in diagnostic endoscopy and transoral endoscopic surgery in daily practice. PMID:27022612

  7. 78 FR 50322 - Amendment of Class E Airspace; Point Thomson, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... Thomson, AK. New Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach... Airstrip Airport, Point Thomson, AK, to accommodate aircraft using new RNAV (GPS) standard...

  8. John Thomson: Photojournalist in Asia, 1862-1872.

    ERIC Educational Resources Information Center

    Parker, Elliott S.

    John Thomson was a nineteenth-century British photojournalist who used the wet-plate process to illustrate his explorations of eastern and Southeast Asia. His travels from 1862 to 1872 took him to the following places, among others: Ceylon, Cambodia, Singapore, Thailand, Saigon, Siam, mainland China, and Taiwan. Thomson chose to use the wet-plate…

  9. Basics of Joule-Thomson Liquefaction and JT Cooling

    NASA Astrophysics Data System (ADS)

    de Waele, A. T. A. M.

    2017-01-01

    This paper describes the basic operation of Joule-Thomson liquefiers and Joule-Thomson coolers. The discussion is based on the first law of thermodynamics mainly using hT-diagrams. It is limited to single-component fluids. A nitrogen liquefier and a helium cooler are discussed as important examples.

  10. Basics of Joule-Thomson Liquefaction and JT Cooling

    NASA Astrophysics Data System (ADS)

    de Waele, A. T. A. M.

    2017-03-01

    This paper describes the basic operation of Joule-Thomson liquefiers and Joule-Thomson coolers. The discussion is based on the first law of thermodynamics mainly using hT-diagrams. It is limited to single-component fluids. A nitrogen liquefier and a helium cooler are discussed as important examples.

  11. Thomson's Theorem of Electrostatics: Its Applications and Mathematical Verification

    ERIC Educational Resources Information Center

    Bakhoum, Ezzat G.

    2008-01-01

    A 100 years-old formula that was given by J. J. Thomson recently found numerous applications in computational electrostatics and electromagnetics. Thomson himself never gave a proof for the formula; but a proof based on Differential Geometry was suggested by Jackson and later published by Pappas. Unfortunately, Differential Geometry, being a…

  12. Spring-Loaded Joule-Thomson Valve

    NASA Technical Reports Server (NTRS)

    Jones, J. A.; Britcliffe, M. J.

    1986-01-01

    Improved design reduces clogging and maintains constant pressure drop as flow rate varies. Spring-Loaded Joule-Thomson Valve pressure drop regulated by spring pushing stainless-steel ball against soft brass seat. Pressure drop remains nearly constant, regardless of helium flow rate and of any gas contaminants frozen on valve seat. Because springloaded J-T valve maintains constant pressure drop, upstream roomtemperature throttle valve adjusts flow rate precisely for any given upstream pressure. In addition, new valve relatively invulnerable to frozen gas contaminants, which clog fixed-orifice J-T valves.

  13. New digital circuits at Thomson semiconductor in France

    NASA Astrophysics Data System (ADS)

    Dellamussia, J. P.

    1985-11-01

    DCS, Thomson Semiconductors' Semi-Standard Circuits Department, has just announced a CMOS gate array with up to 4,200 gates, standard cells, and a unique 900-component, 3 GHz linear gate array. All of Thomson's gate arrays are supported by Daisy, Valid and Mentor workstations. These are the first fruits of a reorganization begun several months ago to distance the department from the actual design and manufacture of integrated circuits, making it more of an archestrator among customers, workstation manufacturers, independent designers and the various Thomson Semiconductors division. Thomson Semiconductors' silicon sales based on DCS contracts totaled 25,000,000 Frances in 1984. This figure should be double in 1985. Thomson Semiconductors plans to offer 120 new integrated circuits this year, twice the number available in 1984. At the same time, the Munich design center and the American subsidiary, VSI, should open new markets in 1985, bringing exports to an estimated 30 percent of sales.

  14. Bose-Einstein condensates of bosonic Thomson atoms

    NASA Astrophysics Data System (ADS)

    Schneider, Tobias; Blümel, Reinhold

    1999-10-01

    A system of charged particles in a harmonic trap is a realization of Thomson's raisin cake model. Therefore, we call it a Thomson atom. Bosonic, fermionic and mixed Thomson atoms exist. In this paper we focus on bosonic Thomson atoms in isotropic traps. Approximating the exact ground state by a condensate we investigate ground-state properties at temperature T = 0 using the Hartree-Fock theory for bosons. In order to assess the quality of our mean-field approach we compare the Hartree-Fock results for bosonic Thomson helium with an exact diagonalization. In contrast to the weakly interacting Bose gas (alkali vapours) mean-field calculations are reliable in the limit of large particle density. The Wigner regime (low particle density) is discussed.

  15. Multicomponent gas sorption Joule-Thomson refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Bard, Steven (Inventor)

    1991-01-01

    The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

  16. 47 CFR 22.621 - Channels for point-to-multipoint operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for point-to-multipoint operation. 22... Channels for point-to-multipoint operation. The following channels are allocated for assignment to... service. Unless otherwise indicated, all channels have a bandwidth of 20 kHz and are designated by...

  17. 47 CFR 22.621 - Channels for point-to-multipoint operation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Channels for point-to-multipoint operation. 22... Channels for point-to-multipoint operation. The following channels are allocated for assignment to... service. Unless otherwise indicated, all channels have a bandwidth of 20 kHz and are designated by...

  18. Capturing rogue waves by multi-point statistics

    NASA Astrophysics Data System (ADS)

    Hadjihosseini, A.; Wächter, Matthias; Hoffmann, N. P.; Peinke, J.

    2016-01-01

    As an example of a complex system with extreme events, we investigate ocean wave states exhibiting rogue waves. We present a statistical method of data analysis based on multi-point statistics which for the first time allows the grasping of extreme rogue wave events in a highly satisfactory statistical manner. The key to the success of the approach is mapping the complexity of multi-point data onto the statistics of hierarchically ordered height increments for different time scales, for which we can show that a stochastic cascade process with Markov properties is governed by a Fokker-Planck equation. Conditional probabilities as well as the Fokker-Planck equation itself can be estimated directly from the available observational data. With this stochastic description surrogate data sets can in turn be generated, which makes it possible to work out arbitrary statistical features of the complex sea state in general, and extreme rogue wave events in particular. The results also open up new perspectives for forecasting the occurrence probability of extreme rogue wave events, and even for forecasting the occurrence of individual rogue waves based on precursory dynamics.

  19. On the integral Joule-Thomson effect

    NASA Astrophysics Data System (ADS)

    Maytal, B.-Z.; Shavit, A.

    In this paper, the integral inversion curve concept is developed, involving the locus of all points with a vanishing integral Joule-Thomson (J-T) effect ΔTh and isothermal enthalpy change. The structure of the ΔhT surface over the plane of ( pr,T r) is explored. The maximum isothermal J-T effect ΔhT is related to the normal boiling temperature of the gas. The correlation of the integral effect based on real gas data with a low acentric factor is compared with Van der Waals' equation of state closed form predictions. The maximum integral isenthalpic J-T effect ΔTh which does not undergo a phase change during the expansion, is studied via Van der Waals' equation of state.

  20. Narrow bandwidth Thomson photon source and diagnostic development using laser-plasma accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, Cameron G. R.; Tsai, Hai-En; van Tilborg, Jeroen; Benedetti, Carlo; Esarey, Eric; Friedman, Alex; Grote, David; Ludewigt, Bernhard; Nakamura, Kei; Quiter, Brian J.; Schroeder, Carl B.; Steinke, Sven; Swanson, Kelly; Toth, Csaba; Vay, Jean-Luc; Vetter, Kai; Zhang, Yigong; Leemans, Wim

    2017-03-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs), and these sources at the same time provide precision diagnostics of beam evolution to support LPA development. We review design of experiments and laser capabilities to realize a photon source, integrating LPA acceleration for compactness, control of scattering to increase photon flux, and electron deceleration to mitigate beam dump size. These experiments are developing a compact photon source system with the potential to enable new monoenergetic photon applications currently restricted by source size, including nuclear nonproliferation. Diagnostic use of the energy-angle spectra of Thomson scattered photons is presented to support development of LPAs to meet the needs of advanced high yield/low-energy-spread photon sources and future high energy physics colliders.

  1. Dual color x rays from Thomson or Compton sources

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Gatti, G.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2014-02-01

    We analyze the possibility of producing two-color x or γ radiation by Thomson/Compton backscattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of realistic experiments.

  2. Exactly maximally convergent multipoint Padé approximants

    NASA Astrophysics Data System (ADS)

    Kovacheva, Ralitza K.

    2016-12-01

    Given a regular compact set E in the complex plane C, a unit measure µ supported by ∂E, a triangular point set β := {βn,kk=1nn=1∞, β ⊂ ∂E and a function f, holomorphic on E, let πn,m β ,f be the associated multipoint β- Padé approximant of order (n, m). We show that if the sequence πn,m β ,f , n ∈ Λ, m- fixed, converges exact maximally to f relatively to the measure µ, then the points βn,k are uniformly distributed on ∂E with respect to µ as n ∈ Λ. Furthermore, a result about the zeros behavior of the exact maximally convergent sequence Λ is provided, under the condition that Λ is "dense enough."

  3. Multipoint Observations of Oval-aligned Transpolar Arc Formation

    NASA Astrophysics Data System (ADS)

    Cumnock, J. A.; Le, G.; Zhang, Y.; Slavin, J. A.

    2013-12-01

    We analyze changes in field-aligned currents associated with auroral oval-aligned transpolar arc formation during quiet times on time scales of a few minutes. This is accomplished using observations from the highly accurate multipoint magnetic field measurements provided by the Space Technology 5 mission which consists of three micro-satellites in low Earth orbit. Simultaneous measurements of precipitating particles are provided by three DMSP satellites. We analyze field-aligned currents associated with the dusk oval. For the first time we observe the field-aligned currents associated with the formation of an oval-aligned transpolar arc poleward of the auroral oval which in one case are large compared with the field-aligned currents associated with the auroral oval measured 10 minutes earlier. These events clearly illustrate the dynamic nature of oval-aligned arc formation.

  4. Multipoint studies of 2D magnetotail current sheet

    NASA Astrophysics Data System (ADS)

    Petrukovich, Anatoli; Zelenyi, Lev; Nakamura, Rumi; Artemyev, Anton

    2016-07-01

    CLUSTER and Themis projects provide unique tools for magnetotail current sheet studies at a wide range of downtail distances: multipoint curlometer allows to measure electric current density, whereas regular electron data contains information on largescale tail structure. Observations show that moderately thin ion-scale embedded sheet is formed during substorm growth phase. Comparison of curlometer with particle data helps to estimate contributions of transient and magnetized ions as well as electrons to current density. Thin intense sheet with sub-ion scale is appearing after onset near reconnection zones, but vertical pressure balance requirement substantially limits the possible range of sheet thickness. Horizontal (along the tail) gradients become more important only in the near tail, within 10-12 Earth radii. Essential quantitative characteristics of ions-scale embedded sheet are boundary field b0 and maximal possible intensity of ion current.

  5. Multipoint mapping of the central core disease locus

    SciTech Connect

    Schwemmle, S.; Wolff, K.; Grimm, T.; Mueller, C.R. ); Palmucci, L.M. ); Lehmann-Horn, F. ); Huebner, Ch. ); Hauser, E. ); Iles, D.E. ); MacLennan, D.H. )

    1993-07-01

    A linkage analysis with 12 DNA markers from proximal 19q was performed in eight families with central core disease (CCO). Two-point analysis gave a peak lod score of Z = 4.95 at [theta] = 0.00 for the anonymous marker D19S190 and of Z = 2.53 at [theta] = 0.00 for the ryanodine receptor (RYR1) candidate gene. Multipoint linkage data place the CCO locus at 19q13.1, flanked proximally by D19S191/D19S28 and distally by D19S47. This map location includes the RYR1 gene. The results of the linkage study present no evidence for genetic heterogeneity of CCO. 19 refs., 2 figs., 1 tab.

  6. Fuzzy logic program at SGS-Thomson

    NASA Astrophysics Data System (ADS)

    Pagni, Andrea; Poluzzi, Rinaldo; Rizzotto, GianGuido

    1993-12-01

    From its conception by Professor Lotfi A. Zadeh in the early '60s, Fuzzy Logic has slowly won acceptance, first in the academic world, then in industry. Its success is mainly due to the different perspective with which problems are tackled. Thanks to Fuzzy Logic we have moved from a numerical/analytical description to a quantitative/qualitative one. It is important to stress that this different perspective not only allows us to solve analysis/control problems at lower costs but can also allow otherwise insoluble problems to be solved at acceptable costs. Of course, it must be stressed that Fuzzy Systems cannot match the computational precision of traditional techniques but seek, instead, to find acceptable solutions in shorter times. Recognizing the enormous importance of fuzzy logic in the markets of the future, SGS-THOMSON intends to produce devices belonging to a new class of machines: Fuzzy Computational Machines. For this purpose a major research project has been established considering the architectural aspects and system implications of fuzzy logic, the development of dedicated VLSI components and supporting software.

  7. Rapid multipoint linkage analysis of recessive traits in nuclear families, including homozygosity mapping

    SciTech Connect

    Kruglyak, L.; Daly, M.J.; Lander, E.S. |

    1995-02-01

    Homozygosity mapping is a powerful strategy for mapping rare recessive traits in children of consanguineous marriages. Practical applications of this strategy are currently limited by the inability of conventional linkage analysis software to compute, in reasonable time, multipoint LOD scores for pedigrees with inbreeding loops. We have developed a new algorithm for rapid multipoint likelihood calculations in small pedigrees, including those with inbreeding loops. The running time of the algorithm grows, at most, linearly with the number of loci considered simultaneously. The running time is not sensitive to the presence of inbreeding loops, missing genotype information, and highly polymorphic loci. We have incorporated this algorithm into a software package, MAPMAKER/HOMOZ, that allows very rapid multipoint mapping of disease genes in nuclear families, including homozygosity mapping. Multipoint analysis with dozens of markers can be carried out in minutes on a personal workstation. 23 refs., 4 figs., 1 tab.

  8. High-resolution wave number spectrum using multi-point measurements in space - the Multi-point Signal Resonator (MSR) technique

    NASA Astrophysics Data System (ADS)

    Narita, Y.; Glassmeier, K.-H.; Motschmann, U.

    2011-02-01

    A new analysis method is presented that provides a high-resolution power spectrum in a broad wave number domain based on multi-point measurements. The analysis technique is referred to as the Multi-point Signal Resonator (MSR) and it benefits from Capon's minimum variance method for obtaining the proper power spectral density of the signal as well as the MUSIC algorithm (Multiple Signal Classification) for considerably reducing the noise part in the spectrum. The mathematical foundation of the analysis method is presented and it is applied to synthetic data as well as Cluster observations of the interplanetary magnetic field. Using the MSR technique for Cluster data we find a wave in the solar wind propagating parallel to the mean magnetic field with relatively small amplitude, which is not identified by the Capon spectrum. The Cluster data analysis shows the potential of the MSR technique for studying waves and turbulence using multi-point measurements.

  9. Super-resolution digital holographic microscopy using multi-point light sources illumination

    NASA Astrophysics Data System (ADS)

    Phan, Anh-Hoang; Park, Jae-Hyeung; Kim, Nam; Jeon, Seok-Hee

    2010-02-01

    In this paper, we use multi-point source illumination to enhance the resolution of digital holographic microscopy without shifting the CCD camera. The specimen is illuminated from many directions by using multi-point sources which are easily created by a lens-array. The high frequency information of the specimen can be captured at a fixed position of CCD camera. All information is then synthesized to increase the resolution.

  10. Improved thermoelectric cooling based on the Thomson effect

    NASA Astrophysics Data System (ADS)

    Snyder, G. Jeffrey; Toberer, Eric S.; Khanna, Raghav; Seifert, Wolfgang

    2012-07-01

    Traditional thermoelectric Peltier coolers exhibit a cooling limit which is primarily determined by the figure of merit, zT. Rather than a fundamental thermodynamic limit, this bound can be traced to the difficulty of maintaining thermoelectric compatibility. Self-compatibility locally maximizes the cooler's coefficient of performance for a given zT and can be achieved by adjusting the relative ratio of the thermoelectric transport properties that make up zT. In this study, we investigate the theoretical performance of thermoelectric coolers that maintain self-compatibility across the device. We find that such a device behaves very differently from a Peltier cooler, and we term self-compatible coolers “Thomson coolers” when the Fourier heat divergence is dominated by the Thomson, as opposed to the Joule, term. A Thomson cooler requires an exponentially rising Seebeck coefficient with increasing temperature, while traditional Peltier coolers, such as those used commercially, have comparatively minimal change in Seebeck coefficient with temperature. When reasonable material property bounds are placed on the thermoelectric leg, the Thomson cooler is predicted to achieve approximately twice the maximum temperature drop of a traditional Peltier cooler with equivalent figure of merit (zT). We anticipate that the development of Thomson coolers will ultimately lead to solid-state cooling to cryogenic temperatures.

  11. ENLIL Global Heliospheric Modeling as a Context For Multipoint Observations

    NASA Astrophysics Data System (ADS)

    Mays, M. Leila; Odstrcil, Dusan; Luhmann, Janet; Bain, Hazel; Li, Yan; Schwadron, Nathan; Gorby, Matt; Thompson, Barbara; Jian, Lan; Möstl, Christian; Rouillard, Alexis; Davies, Jackie; Temmer, Manuela; Rastaetter, Lutz; Taktakishvili, Aleksandre; MacNeice, Peter; Kuznetsova, Maria

    2016-04-01

    We present heliospheric simulation case studies using recent enhancements to WSA--ENLIL+Cone (version 2.8) at the Community Coordinated Modeling Center (CCMC). The global 3D MHD ENLIL model provides a time-dependent description of the background solar wind plasma and magnetic field using a sequence of WSA coronal model maps as input at the inner boundary of 21.5 Rs. A homogeneous, over-pressured hydrodynamic plasma cloud is launched through the inner boundary of the heliospheric computational domain and into the background solar wind. Multipoint observations help constrain simulations and this modeling system provides global context and arrival times of the solar wind streams and CMEs at Earth, planets, and spacecraft. Additionally, one can extract the magnetic topologies of observer-connected magnetic field lines and all plasma and shock properties along those field lines. ENLIL "likelihood/all-clear" forecasting maps provide expected intensity, timing/duration of events at locations throughout the heliosphere with "possible SEP affected areas" color-coded based on shock strength. ENLIL simulations are also useful to drive SEP models such as the Solar Energetic Particle Model (SEPMOD) (Luhmann et al. 2007, 2010) and Energetic Particle Radiation Environment Module (EPREM) (Schwadron et al., 2010). SEPMOD injects protons onto a sequence observer field lines at intensities dependent on the connected shock source strength which are then integrated at the observer to approximate the proton flux. EPREM couples with MHD models such as ENLIL and computes energetic particle distributions based on the focused transport equation along a Lagrangian grid of nodes that propagate out with the solar wind. Studies have shown that accurate descriptions of the heliosphere, and hence modeled CME arrival times and SEPs, are achieved by ENLIL only when the background solar wind is well-reproduced and CME parameters are accurate. It is essential to include all of the relevant CMEs and

  12. From a land of saints and scholars? Reflections on William Thomson's religious background

    NASA Astrophysics Data System (ADS)

    McCartney, Mark

    2009-04-01

    After indicating the range of biographical studies of William Thomson since his death in 1907, the roots of Thomson's religious views are traced back to those of his father, James Thomson, and following the work of David B Wilson, to those of his teachers at the University of Glasgow in the 1830s.

  13. Narrow bandwidth Thomson photon source development using Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Geddes, C. G. R.; van Tilborg, J.; Tsai, H.-E.; Toth, Cs.; Vay, J.-L.; Lehe, R.; Schroeder, C. B.; Esarey, E.; Rykovanov, S. G.; Grote, D. P.; Friedman, A.; Leemans, W. P.

    2016-10-01

    Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs). An independent scattering laser with controlled pulse shaping in frequency and amplitude can be used together with laser guiding to realize high photon yield and narrow bandwidth. Simulations are presented on production of controllable narrow bandwidth sources using the beam and plasma capabilities of LPAs. Recent experiments and simulations demonstrate controllable LPAs in the energy range appropriate to MeV Thomson sources. Design of experiments and laser capabilities to combine these elements will be presented, towards a compact photon source system. A dedicated facility under construction will be described. Work supported by US DOE NNSA DNN R&D and by Sc. HEP under contract DE-AC02-05CH11231.

  14. Sub-MeV tunably polarized X-ray production with laser Thomson backscattering

    SciTech Connect

    Kawase, K.; Kando, M.; Hayakawa, T.; Daito, I.; Kondo, S.; Homma, T.; Kameshima, T.; Kotaki, H.; Chen, L.-M.; Fukuda, Y.; Faenov, A.; Shizuma, T.; Fujiwara, M.; Bulanov, S. V.; Kimura, T.; Tajima, T.

    2008-05-15

    Reported in this article is the generation of unique polarized x-rays in the sub-MeV region by means of the Thomson backscattering of the Nd:YAG laser photon with a wavelength of 1064 nm on the 150 MeV electron from the microtron accelerator. The maximum energy of the x-ray photons is estimated to be about 400 keV. The total energy of the backscattered x-ray pulse is measured with an imaging plate and a LYSO scintillator. The angular divergence of the x-rays is also measured by using the imaging plate. We confirm that the x-ray beam is polarized according to the laser polarization direction with the Compton scattering method. In addition, we demonstrate the imaging of the object shielded by lead with the generated x-rays.

  15. Communication: Ab initio Joule-Thomson inversion data for argon

    NASA Astrophysics Data System (ADS)

    Wiebke, Jonas; Senn, Florian; Pahl, Elke; Schwerdtfeger, Peter

    2013-02-01

    The Joule-Thomson coefficient μH(P, T) is computed from the virial equation of state up to seventh-order for argon obtained from accurate ab initio data. Higher-order corrections become increasingly more important to fit the low-temperature and low-pressure regime and to avoid the early onset of divergence in the Joule-Thomson inversion curve. Good agreement with experiment is obtained for temperatures T > 250 K. The results also illustrate the limitations of the virial equation in regions close to the critical temperature.

  16. Cathode Ray Research Leading to J.J. Thomson's Discovery

    NASA Astrophysics Data System (ADS)

    Mulligan, Joseph

    1997-04-01

    This paper reviews the research on the properties and nature of cathode rays that led to the discovery of the electron by J. J. Thomson in the years 1897 - 1899. During the period from about 1870 to 1897 important research on cathode rays was carried out by William Crookes and Arthur Schuster in England, by Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Emil Wiechert and Walter Kaufman in Germany, and by Jean Perrin in France. This research was always tedious and often inexact because fast vacuum pumps and convenient vacuum gauges did not yet exist. Still a few of these earlier researchers narrowly missed beating J. J. Thomson to the discover of the electron.

  17. Improved thermoelectric cooling based on the Thomson effect

    NASA Astrophysics Data System (ADS)

    Snyder, G. Jeffrey; Khanna, Raghav; Toberer, Eric S.; Heinz, Nicholas A.; Seifert, Wolfgang

    2016-05-01

    Traditional thermoelectric cooling relies on the Peltier effect which produces a temperature drop limited by the figure of merit, zT. This cooling limit is not required from classical thermodynamics but can be traced to problems of thermoelectric compatibility. Alternatively, if a thermoelectric cooler can be designed to achieve full thermoelectric compatibility, lower temperature can be achieved even if the zT is low. In such a device the Thomson effect plays an important role. We present the theoretical concept of a "Thomson cooler," for cryogenic cooling which is designed to maintain thermoelectric compatibility and we derive the requirements for the Seebeck coefficient.

  18. Program For Joule-Thomson Analysis Of Mixed Cryogens

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Lund, Alan

    1994-01-01

    JTMIX computer program predicts ideal and realistic properties of mixed gases at temperatures between 65 and 80 K. Performs Joule-Thomson analysis of any gaseous mixture of neon, nitrogen, various hydrocarbons, argon, oxygen, carbon monoxide, carbon dioxide, and hydrogen sulfide. When used in conjunction with DDMIX computer program of National Institute of Standards and Technology (NIST), JTMIX accurately predicts order-of-magnitude increases in Joule-Thomson cooling capacities occuring when various hydrocarbons added to nitrogen. Also predicts boiling temperature of nitrogen depressed from normal value to as low as 60 K upon addition of neon. Written in Turbo C.

  19. Communication: Ab initio Joule-Thomson inversion data for argon.

    PubMed

    Wiebke, Jonas; Senn, Florian; Pahl, Elke; Schwerdtfeger, Peter

    2013-02-21

    The Joule-Thomson coefficient μ(H)(P, T) is computed from the virial equation of state up to seventh-order for argon obtained from accurate ab initio data. Higher-order corrections become increasingly more important to fit the low-temperature and low-pressure regime and to avoid the early onset of divergence in the Joule-Thomson inversion curve. Good agreement with experiment is obtained for temperatures T > 250 K. The results also illustrate the limitations of the virial equation in regions close to the critical temperature.

  20. Dynamic Loads Generation for Multi-Point Vibration Excitation Problems

    NASA Technical Reports Server (NTRS)

    Shen, Lawrence

    2011-01-01

    A random-force method has been developed to predict dynamic loads produced by rocket-engine random vibrations for new rocket-engine designs. The method develops random forces at multiple excitation points based on random vibration environments scaled from accelerometer data obtained during hot-fire tests of existing rocket engines. This random-force method applies random forces to the model and creates expected dynamic response in a manner that simulates the way the operating engine applies self-generated random vibration forces (random pressure acting on an area) with the resulting responses that we measure with accelerometers. This innovation includes the methodology (implementation sequence), the computer code, two methods to generate the random-force vibration spectra, and two methods to reduce some of the inherent conservatism in the dynamic loads. This methodology would be implemented to generate the random-force spectra at excitation nodes without requiring the use of artificial boundary conditions in a finite element model. More accurate random dynamic loads than those predicted by current industry methods can then be generated using the random force spectra. The scaling method used to develop the initial power spectral density (PSD) environments for deriving the random forces for the rocket engine case is based on the Barrett Criteria developed at Marshall Space Flight Center in 1963. This invention approach can be applied in the aerospace, automotive, and other industries to obtain reliable dynamic loads and responses from a finite element model for any structure subject to multipoint random vibration excitations.

  1. Development of a Multi-Point Microwave Interferometry (MPMI) Method

    SciTech Connect

    Specht, Paul Elliott; Cooper, Marcia A.; Jilek, Brook Anton

    2015-09-01

    A multi-point microwave interferometer (MPMI) concept was developed for non-invasively tracking a shock, reaction, or detonation front in energetic media. Initially, a single-point, heterodyne microwave interferometry capability was established. The design, construction, and verification of the single-point interferometer provided a knowledge base for the creation of the MPMI concept. The MPMI concept uses an electro-optic (EO) crystal to impart a time-varying phase lag onto a laser at the microwave frequency. Polarization optics converts this phase lag into an amplitude modulation, which is analyzed in a heterodyne interfer- ometer to detect Doppler shifts in the microwave frequency. A version of the MPMI was constructed to experimentally measure the frequency of a microwave source through the EO modulation of a laser. The successful extraction of the microwave frequency proved the underlying physical concept of the MPMI design, and highlighted the challenges associated with the longer microwave wavelength. The frequency measurements made with the current equipment contained too much uncertainty for an accurate velocity measurement. Potential alterations to the current construction are presented to improve the quality of the measured signal and enable multiple accurate velocity measurements.

  2. Multipoint observations of Ionospheric Alfvén Resonance

    NASA Astrophysics Data System (ADS)

    Baru, N. A.; Koloskov, A. V.; Yampolsky, Y. M.; Rakhmatulin, R. A.

    2016-09-01

    Among the processes that form properties of the geospace in the circumterrestrial plasma the electromagnetic resonances of the Earth, such as Schummann Resonance (SR) and Ionospheric Alfvén Resonance (IAR) are of great importance. IAR is more localized in space than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is continuously observable at any time of the day, IAR signals are registered mostly during the nighttime and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure of the natural electromagnetic noise at frequency range 0.1-40 Hz. In this work we studied an influence of the environment characteristics on IAR parameters by the means of multipoint observations. Annual data series recorded at Ukrainian Antarctic Station "Akademik Vernadsky", Low Frequency Observatory of the Institute of Radio Astronomy near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. We investigated the behaviour of IAR parameters, such as probability of resonance lines registration and frequency spacing Δ F, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere above all of the observation points and geomagnetic activity.

  3. Local multipoint distribution system (LDMS) versus free-space optical (FSO) networks

    NASA Astrophysics Data System (ADS)

    Willebrand, Heinz A.; Clark, Gerald R.; Willson, Bryan; Andreu von Euw, Christian G.; Roy, Joe; Mayhew, Laurel M.

    2001-11-01

    This paper compares two emerging broadband access methodologies, Free Space Optics (FSO) and Local Multipoint Distribution System (LMDS) and the atmospheric propagation characteristics of each when exposed to a dynamically changing channel. The comparison focuses on bandwidth, availability, and distance requirements for the new broadband market and how LMDS and FSO can be used to meet these requirements. Possible network topologies and their associated costs are examined. This comparison takes into account the total cost of deployment, including equipment costs, installation fees, access fees, and spectrum licensing fees. LMDS and FSO are compared on speed of deployment, scalability, aggregate bandwidth, and bandwidth per customer. Present and projected capabilities of each technology are considered for their suitability in different locations in the network, from the Wide Area Network (WAN), to the Metropolitan Area Network (MAN), all the way to Last Mile Access. There is a discussion on the relative performance of LMDS and FSO, focusing on the different factors that can affect link availability. Since network design is a large factor in assuring overall reliability, the flexibility of each technology with regard to network design is compared. LMDS and FSO are both line of sight, space-propagated technologies, and as such, they are both susceptible to path impediments and atmospheric attenuation, dispersion, scattering, and absorption. LMDS and FSO are affected very differently by different meteorological phenomena. Problematic atmospheric conditions are, specifically scintillation, rainfall, and fog, are examined. In addition to a discussion of these conditions, various techniques for minimizing atmospheric and environmental effects are investigated. The paper concludes with a summary of findings and recommendations for a number of broadband wireless applications.

  4. The Thomson deflectometer: A novel use of the Thomson spectrometer as a transient field and plasma diagnostic

    SciTech Connect

    Ter-Avetisyan, S.; Schnuerer, M.; Nickles, P. V.; Sokollik, T.; Risse, E.; Kalashnikov, M.; Sandner, W.; Priebe, G.

    2008-03-15

    Laser accelerated proton beams have been used for field characterization in expanding plasmas. The Thomson parabola spectrometer, as a charged particles analyzer, also allows precise measurement of the charged particles' trajectories. The proton's deflections by fast changing plasma fields can be measured with the new design of the Thomson parabola spectrometer and, therefore, it can be applied for proton deflectometry. It is shown that from resulting spectrograms the plasma field dynamics can be reconstructed with high temporal resolution. In a proof-of-principle experiment, a weakly relativistic plasma expansion is studied as an example.

  5. Joule-Thomson coefficient of ideal anyons within fractional exclusion statistics

    SciTech Connect

    Qin Fang; Chen Jisheng

    2011-02-15

    The analytical expressions of the Joule-Thomson coefficient for homogeneous and harmonically trapped three-dimensional ideal anyons which obey Haldane fractional exclusion statistics are derived. For an ideal Fermi gas, the Joule-Thomson coefficient is negative, which means that there is no maximum Joule-Thomson inversion temperature. With careful study, it is found that there exists a Joule-Thomson inversion temperature in the fractional exclusion statistics model. Furthermore, the relations between the Joule-Thomson inversion temperature and the statistical parameter g are investigated.

  6. Joule-Thomson coefficient of ideal anyons within fractional exclusion statistics.

    PubMed

    Qin, Fang; Chen, Ji-sheng

    2011-02-01

    The analytical expressions of the Joule-Thomson coefficient for homogeneous and harmonically trapped three-dimensional ideal anyons which obey Haldane fractional exclusion statistics are derived. For an ideal Fermi gas, the Joule-Thomson coefficient is negative, which means that there is no maximum Joule-Thomson inversion temperature. With careful study, it is found that there exists a Joule-Thomson inversion temperature in the fractional exclusion statistics model. Furthermore, the relations between the Joule-Thomson inversion temperature and the statistical parameter g are investigated.

  7. The similarity law for the Joule-Thomson inversion line.

    PubMed

    Apfelbaum, E M; Vorob'ev, V S

    2014-10-23

    We show that the expression for the Joule-Thomson inversion temperature following from the van der Waals equation and recorded in a form reduced to the Boyle values has a universal character and can be applied to many real substances and model systems.

  8. Mixed-Gas Sorption Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Petrick, S. Walter; Bard, Steven

    1991-01-01

    Proposed mixed-gas sorption Joule-Thomson refrigerator provides cooling down to temperature of 70 K. Includes only one stage and no mechanical compressor. Simpler, operates without vibrating, and consumes less power in producing same amount of cooling. Same sorption principle of operation applicable in compressor that chemisorbs oxygen or hydrogen from mixture with helium, neon, and/or other nonreactive gases.

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

    DOEpatents

    Barty, Christopher P. J.; Hartemann, Frederic V.; McNabb, Dennis P.; Pruet, Jason A.

    2009-07-21

    The present invention utilizes novel laser-based, high-brightness, high-spatial-resolution, pencil-beam sources of spectrally pure hard x-ray and gamma-ray radiation to induce resonant scattering in specific nuclei, i.e., nuclear resonance fluorescence. By monitoring such fluorescence as a function of beam position, it is possible to image in either two dimensions or three dimensions, the position and concentration of individual isotopes in a specific material configuration. Such methods of the present invention material identification, spatial resolution of material location and ability to locate and identify materials shielded by other materials, such as, for example, behind a lead wall. The foundation of the present invention is the generation of quasimonochromatic high-energy x-ray (100's of keV) and gamma-ray (greater than about 1 MeV) radiation via the collision of intense laser pulses from relativistic electrons. Such a process as utilized herein, i.e., Thomson scattering or inverse-Compton scattering, produces beams having diameters from about 1 micron to about 100 microns of high-energy photons with a bandwidth of .DELTA.E/E of approximately 10E.sup.-3.

  10. Polaritonic pulse and coherent X- and gamma rays from Compton (Thomson) backscattering

    SciTech Connect

    Apostol, M.; Ganciu, M.

    2011-01-01

    The formation of polariton wave-packets created by high-intensity laser beams focused in plasmas is analyzed, and the velocity, energy, size, structure, stability, and electron content of such polaritonic pulses are characterized. It is shown that polaritonic pulses may transport trapped electrons with appreciable energies, provided the medium behaves as a rarefied classical plasma. The relativistic electron energy is related to the polariton group velocity, which is close to the velocity of light in this case. The plasma pulse is polarized, and the electron number in the pulse is estimated as being proportional to the square root of the laser intensity and the 3/2-power of the pulse size. It is shown that Compton (Thomson) backscattering by such polaritonic pulses of electrons may produce coherent X- and gamma rays, as a consequence of the quasirigidity of the electrons inside the polaritonic pulses and their relatively large number. The classical results of the Compton scattering are re-examined in this context, the energy of the scattered photons and their cross-section are analyzed, especially for backscattering, the great enhancement of the scattered flux of X- or gamma rays due to the coherence effect is highlighted and numerical estimates are given for some typical situations.

  11. Solar Cycle Variation and Multipoint Studies of ICME Properties

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    2005-01-01

    The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, Wind, ACE and Pioneer Venus in quadrature, multipoint, and solar cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the solar wind conditions associated with these structures are the most geoeffective of any solar wind phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient solar wind producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient solar wind, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the solar wind [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient solar wind and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.

  12. Cluster Multi-Point Studies of the Auroral Acceleration Region

    NASA Astrophysics Data System (ADS)

    Marklund, G. T.

    2014-12-01

    Multi-point studies of the auroral acceleration region (AAR) by the Cluster spacecraft has enabled a number of open issues on the auroral acceleration to be addressed and revealed. Data from AAR crossings of Inverted-V aurora, by the C1 and C3 spacecraft at different altitudes, enabled a detailed reconstruction of the acceleration potential and a verification of its stability on a five min time scale. The relative role of quasi-static and Alfvénic acceleration behind aurora are addressed in two event studies. In one of these, the two processes are shown to operate jointly on the plasma population within the polar cap boundary. In the other, the electron energy flux producing multiple arcs within a surge is found to be generally dominated by the quasi-static contribution. Acceleration features and the FAC closure associated with surge-horn aurora crossed by the Cluster fleet were derived in another event study. A study of the density distribution within the auroral cavity, showed for all included events, exponential density decreases, relative to the ambient densities, from the mid to top of the AAR. In another study, cavities were found to extend well beyond the top of the AAR. Finally, statistical high-latitude electric field and plasma density distributions are presented based on 10 years of Cluster data collected between 2 and 4 RE altitudes. Intense electric fields appear in two altitude regimes on the nightside, separated by a gap at 2.8 RE. The upper altitude fields were interpreted to be Alfvénic and the lower altitude fields quasi-static, related to the AAR. The gap in the electric field intensity indicates a partial closure of the potentials in the lower region, with similarities to model results of reflected Alfvén waves and earlier reported observations

  13. On shifted Jacobi spectral method for high-order multi-point boundary value problems

    NASA Astrophysics Data System (ADS)

    Doha, E. H.; Bhrawy, A. H.; Hafez, R. M.

    2012-10-01

    This paper reports a spectral tau method for numerically solving multi-point boundary value problems (BVPs) of linear high-order ordinary differential equations. The construction of the shifted Jacobi tau approximation is based on conventional differentiation. This use of differentiation allows the imposition of the governing equation at the whole set of grid points and the straight forward implementation of multiple boundary conditions. Extension of the tau method for high-order multi-point BVPs with variable coefficients is treated using the shifted Jacobi Gauss-Lobatto quadrature. Shifted Jacobi collocation method is developed for solving nonlinear high-order multi-point BVPs. The performance of the proposed methods is investigated by considering several examples. Accurate results and high convergence rates are achieved.

  14. Fluid flow and heat transfer in Joule-Thomson coolers coupled with infrared detectors

    NASA Astrophysics Data System (ADS)

    Du, Bingyan; Jia, Weimin

    2011-08-01

    Joule-Thomson coolers have been widely used in infrared detectors with respect to compact, light and low cost. For self-regulating Joule-Thomson cooler, its performance is required to be improved with the development of higher mass and larger diameter of focal plane infrared detectors. Self-regulating Joule-Thomson coolers use a limited supply of high pressure gas to support the cooling of infrared detectors. In order to develop Joule-Thomson coolers with a given volume of stored gas, it is important to study on fluid flow and heat transfer of Joule-Thomson coolers coupled with infrared detectors, especially the starting time of Joule-Thomson coolers. A serial of experiments of Joule-Thomson coolers coupled with 128×128 focal plane infrared detectors have been carried out. The exchanger of coolers are made of a d=0.5mm capillary finned with a copper wire. The coolers are self-regulated by bellows and the diameters are about 8mm. Nitrogen is used as working gas. The effect of pressure of working gas has been studied. The relation between starting time and pressure of working gas is proved to fit exponential decay. Error analysis has also been carried. It is crucial to study the performance of Joule-Thomson coolers coupled with infrared detectors. Deeper research on Joule-Thomson coolers will be carried on to improve the Joule-Thomson coolers for infrared detectors.

  15. Multipoint Lods Provide Reliable Linkage Evidence Despite Unknown Limiting Distribution: Type I Error Probabilities Decrease with Sample Size for Multipoint Lods and Mods

    PubMed Central

    Hodge, Susan E.; Rodriguez-Murillo, Laura; Strug, Lisa J.; Greenberg, David A.

    2009-01-01

    We investigate the behavior of type I error rates in model-based multipoint (MP) linkage analysis, as a function of sample size (N). We consider both MP lods (i.e., MP linkage analysis that uses the correct genetic model) and MP mods (maximizing MP lods over 18 dominant and recessive models). Following Xing & Elston [2006], we first consider MP linkage analysis limited to a single position; then we enlarge the scope and maximize the lods and mods over a span of positions. In all situations we examined, type I error rates decrease with increasing sample size, apparently approaching zero. We show: (a) For MP lods analyzed only at a single position, well-known statistical theory predicts that type I error rates approach zero. (b) For MP lods and mods maximized over position, this result has a different explanation, related to the fact that one maximizes the scores over only a finite portion of the parameter range. The implications of these findings may be far-reaching: Although it is widely accepted that fixed nominal critical values for MP lods and mods are not known, this study shows that whatever the nominal error rates are, the actual error rates appear to decrease with increasing sample size. Moreover, the actual (observed) type I error rate may be quite small for any given study. We conclude that multipoint lod and mod scores provide reliable linkage evidence for complex diseases, despite the unknown limiting distributions of these multipoint scores. PMID:18613118

  16. Cryogenic characterization of low-cost Joule-Thomson coolers

    NASA Astrophysics Data System (ADS)

    Guichard, Jerome; Cottereau, Alain; Chazot, Dominique

    2000-12-01

    This paper highlights two main achievements which were performed by AIR LIQUIDE during the last decade in the field of low cost Joule-Thomson coolers. On one hand, in order to comply with new geometrical requirements, AIR LIQUIDE is able to propose a flat cooler. This compact geometry is enabled by a new, cheap, type of heat exchanger. It offers a better resistance to external vibrations. On the other hand AIR LIQUIDE has developed, in the frame of a commercial program, a complete cryogenic cooling system, composed of a dual flow Joule-Thomson cooler, a pressurized gas capacity equipped with a manifold block and a pyrotechnic actuator, and the requested pipes and connectors. The dual flow is enabled by flexion of a washer made of shape memory alloy.

  17. Thomson Reuters to release Book Citation Index later this year

    NASA Astrophysics Data System (ADS)

    Aldred, Maxine

    2011-08-01

    Thomson Reuters will launch its new Book Citation Index later this year. Projected to include 25,000 volumes from major publishers and university presses in science, social science, and the humanities, the Book Citation Index will cover scholarly books (both series and nonseries) that present original research or literature reviews. The current effort regarding the science section is focused on books published from 2005 to the present. AGU has sent copies of its catalog for inclusion in the Book Citation Index, but the final selection will be made by Thomson Reuters, using its internal selection criteria, which may be found at http://wokinfo.com/wok/media/pdf/BKCI-SelectionEssay_web.pdf.

  18. Comparative Exergetic Analysis of Joule-Thomson Liquefiers

    NASA Astrophysics Data System (ADS)

    Chorowski, Maciej

    2004-06-01

    The Joule-Thomson microliquefiers are very reliable and noiseless cryocoolers, specially well fitted for cryostating small electronic devices, IR detectors or cryosurgical probes. Their essential drawback is low thermodynamic efficiency imposing high supply gas pressure, usually above 10 MPa. An exergetic analysis of the microliquefier has been performed and exergy-loss sources identified. Some of the losses can be avoided if a pure gas is replaced with a proper gas mixture and in result the supply gas pressure can be lowered significantly. The efficiencies and working parameters of Joule-Thomson microliquefier fed with pure N2 and the mixtures N2 - CH4 and N2 - R13 have been estimated and measured. The mixture properties have been calculated using the Peng-Robinson equation of state. The possibility to use a liquid-solid phase transition in a cooling-power "on-off" control loop has been observed.

  19. Meson production based on the Thomson energy correlation

    SciTech Connect

    Aspden, H.

    1986-07-01

    Attention is drawn to a remarkable energy correlation which uniquely determines the rest-mass energies of all the intermediate particles in the electron-proton energy spectrum. The correlation formula uses a classical expression formulated by J. J. Thomson, which represents the charge of a particle as confined within a sphere of radius 2e/sup 2//3mc/sup 2/.

  20. The Joule-Thomson effect in confined fluids

    NASA Astrophysics Data System (ADS)

    Schoen, Martin

    1999-08-01

    The Joule-Thomson effect is discussed for a fluid composed of spherically symmetric Lennard-Jones(12,6) molecules (of “diameter” σ) confined between two planar, rigid, structureless solid substrates separated by sz=10 and 20 σ. The effect of “strong” and “weak” of the substrate is studied by employing fluid-substrate potentials with and without attractive interactions, respectively. The focal point of this study is the confinement-induced depression of the inversion temperature Tinv with respect to the bulk value. It is defined such that during a Joule-Thomson expansion the temperature of a (confined or bulk) gas remains constant. In the limit of vanishing gas density, Tinv is computed from the second virial coefficient defined through a density expansion of the transverse stress T∥ in the gas. For higher densities Tinv is computed from the (transverse) expansion coefficient α∥ which is accessible through density and enthalpy fluctuations in mixed stress-strain ensemble Monte Carlo simulations. Results of these simulations are analyzed in terms of a mean-field theory which provides a qualitatively correct description of the Joule-Thomson effect in confined fluids. The smaller sz the more depressed (with respect to the bulk) is Tinv. The density dependence of Tinv is different for “strong” and “weak” substrates. Without attractive fluid-fluid interactions Tinv does not exist and the confined gas is always heated during a Joule-Thomson expansion. In this case α∥ is independent of the substrate material.

  1. Joule—Thomson effect in liquid He II

    NASA Astrophysics Data System (ADS)

    Huang, B. J.

    It has been shown in the present study that the Joule—Thomson coefficients of liquid He II are extraordinarily high for temperatures far below the lambda point as compared with ordinary real gases or liquids. Its effect on the throttling process of He II was shown to be quite significant and should be taken into account when dealing with transport processes of He II.

  2. Exploring Solute Transport and Streamline Connectivity Using Two-point and Multipoint Simulation Methods

    NASA Astrophysics Data System (ADS)

    Klise, K. A.; McKenna, S. A.; Tidwell, V. C.; Lane, J. W.; Weissmann, G. S.; Wawrzyniec, T. F.; Nichols, E. M.

    2008-12-01

    Sequential indicator simulation is widely used to create lithofacies models based on the two-point correlation of the desired heterogeneous field. However, two-point correlation (i.e. the variogram) is not capable of preserving complex patterns such as connected curvilinear structures often noted in realistic geologic media. As an alternative, several multipoint simulation methods have been suggested to replicate structural patterns based on a training image. To understand the implications that two-point and multipoint methods have on predicting solute transport, rigorous tests are needed that use realistic aquifer analogs. For this study, we use high-resolution terrestrial lidar scans to identify sand and gravel lithofacies at the outcrop (meter) scale. The lithofacies map serves as the aquifer analog and is used as a training image. The use of two-point (sisim) and multipoint (filtersim and snesim) stochastic simulation methods are then compared based on the ability of the resulting simulations to replicate solute transport characteristics using the aquifer analog. Detailed particle tracking simulations are used to explore the streamline-based connectivity that is preserved using each method. Based on the three simulation methods tested here, filtersim, a multipoint method that replicates structural patterns seen in the aquifer analog, best predicts non- Fickian solute transport characteristics by matching the connectivity of facies along streamlines. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04- 94AL85000.

  3. Experimental study of a multipoint cathode corona in an argon flow

    SciTech Connect

    Baldanov, B. B.

    2009-07-15

    Results are presented from experimental studies of a multipoint negative corona in an atmospheric-pressure argon flow. It is shown that a decrease in the interpoint distance, gas circulation through the discharge gap, and the adjustment of ballast resistances in the corona supply circuit allow one to stabilize the discharge and enlarge the operating range of discharge currents.

  4. Multi-Point E-Conferencing with Initial Teacher Training Students in England: Pitfalls and Potential

    ERIC Educational Resources Information Center

    Pratt, Nick

    2008-01-01

    This article reports on attempts to initiate multi-point e-conferencing between English teacher education students on school placements, their host teachers and their university tutors. A sociocultural perspective is adopted in analysing the project, using the metaphor of a "professional knowledge landscape" [Clandinin, D. J., &…

  5. Point-to-multipoint holographic beamsteering techniques for indoor optical wireless communications

    NASA Astrophysics Data System (ADS)

    Gomez, A.; Quintana, Crisanto; Faulkner, Grahame; O'Brien, Dominic

    2016-02-01

    Fibre-to-the-home deployment is enabling ultra-high speed communications to reach the end-user in many cities. Most users would like to access this capacity using wireless devices. However, available wireless technologies can handle data rates often many orders of magnitude slower than those potentially offered by the fibre infrastructure. This paper describes an optical wireless architecture that bridges this gap by using the light directly from the fibre to create an indoor point-to-multipoint transparent distribution system. The approach is all optical, thus inherently independent of the data-rate and modulation formats. A holographic beamsteering device is used to direct narrow 1550 nm beams to the receivers' locations. Specifically, a spatial light modulator (SLM), assisted by angle magnification optics allowed for a +/-30° field-of-view coverage in both the horizontal and vertical directions. In this work we experimentally study two different methods to generate the point-to-multipoint capability: spatial division of the SLM in independent phaseprogrammable regions and the Gerchberg-Saxton (GS) multipoint hologram generation algorithm. These methods were compared for a 2-beam beamsteering system at a range of ~ 2 meters. Results show that the spatial division approach creates more stable links with higher optical margins. However, the GS-based steering offers a more scalable solution for a point-to-multipoint architecture that addresses a large number of end-users.

  6. Innovation as a social process: Elihu Thomson and the rise of General Electric, 1870-1900

    SciTech Connect

    Carlson, W.B.

    1992-01-01

    This book traces the development of the General Electric Corporation by following the career of inventor Elihu Thomson, who along with Thomas Edison and George Westinghouse, achieved recoginition for the rapid emergence of electric light and power in America. The author explores Thomson's development as an inventor and scientist. He goes on to examine how Thomson applied his innovation and scientific skills in the marketplace, tracks the development of the Thomson-Houston Company and subsequent merger with Edison into General Electric. Book review.

  7. Interferometric Rayleigh Scattering Measurement System

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Danehy, Paul M. (Inventor); Lee, Joseph W. (Inventor)

    2008-01-01

    A method and apparatus for performing simultaneous multi-point measurements of multiple velocity components in a gas flow is described. Pulses of laser light are directed to a measurement region of unseeded gas to produce Rayleigh or Mie scattered light in a plurality of directions. The Rayleigh or Mie scattered light is collected from multiple directions and combined in a single collimated light beam. The Rayleigh or Mie scattered light is then mixed together with a reference laser light before it is passed through a single planar Fabry-Perot interferometer for spectral analysis. At the output of the interferometer, a high-sensitivity CCD camera images the interference fringe pattern. This pattern contains the spectral and spatial information from both the Rayleigh scattered light and the reference laser light. Interferogram processing software extracts and analyzes spectral profiles to determine the velocity components of the gas flow at multiple points in the measurement region. The Rayleigh light rejected by the interferometer is recirculated to increase the accuracy and the applicability of the method for measurements at high temperatures without requiring an increase in the laser energy.

  8. Non-coherent Continuum Scattering as a Line Polarization Mechanism

    NASA Astrophysics Data System (ADS)

    del Pino Alemán, T.; Manso Sainz, R.; Trujillo Bueno, J.

    2014-03-01

    Line scattering polarization can be strongly affected by Rayleigh scattering at neutral hydrogen and Thomson scattering at free electrons. Often a depolarization of the continuum results, but the Doppler redistribution produced by the continuum scatterers, which are light (hence, fast), induces more complex interactions between the polarization in spectral lines and in the continuum. Here we formulate and solve the radiative transfer problem of scattering line polarization with non-coherent continuum scattering consistently. The problem is formulated within the spherical tensor representation of atomic and light polarization. The numerical method of solution is a generalization of the Accelerated Lambda Iteration that is applied to both the atomic system and the radiation field. We show that the redistribution of the spectral line radiation due to the non-coherence of the continuum scattering may modify the shape of the emergent fractional linear polarization patterns significantly, even yielding polarization signals above the continuum level in intrinsically unpolarizable lines.

  9. The Kelvin-Thomson Atom. Part 2: The Many-Electron Atoms

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1977-01-01

    Presents part two of a two-part article describing the Kelvin-Thomson atom. This part discusses the arrangement of electrons within the atom and examines some of the properties predicted for elements in the Kelvin-Thomson model. (SL)

  10. Miniature Joule - Thomson liquefier with sintered heat exchanger

    NASA Astrophysics Data System (ADS)

    Eugeniusz, Bodio; Maciej, Chorowski; Marta, Wilczek; Arkadiusz, Bozek

    Conventional Joule-Thomson refrigerators are made with finned, capillary tubing for the heat exchanger and a throttling valve for reducing the pressure [1]. A new kind of recuperative miniature heat-exchanger can be developed if a powder metallurgy technology is used. A high pressure capillary tube is sintered with metal powder. The grains of metal should be ball shaped or similar. In result of sintering process a good thermal contact between an outside tube surface and powder grains is achieved. The heat exchange surface is well developed and a porous sinter acts as a low pressure gas canal.

  11. Stability of charge inversion, Thomson problem, and application to electrophoresis

    NASA Astrophysics Data System (ADS)

    Patra, Michael; Patriarca, Marco; Karttunen, Mikko

    2003-03-01

    We analyze charge inversion in colloidal systems at zero temperature using stability concepts, and connect this to the classical Thomson problem of arranging electrons on sphere. We show that for a finite microion charge, the globally stable, lowest-energy state of the complex formed by the colloid and the oppositely charged microions is always overcharged. This effect disappears in the continuous limit. Additionally, a layer of at least twice as many microions as required for charge neutrality is always locally stable. In an applied external electric field the stability of the microion cloud is reduced. Finally, this approach is applied to a system of two colloids at low but finite temperature.

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

    PubMed Central

    Beckmann, Nicholas

    2015-01-01

    Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis characterized by a poikilodermatous rash starting in infancy as well as various skeletal anomalies, juvenile cataracts, and predisposition to certain cancers. Although Rothmund-Thomson syndrome is associated with diminished bone mineral density in addition to multiple skeletal abnormalities, there are few reports of the association with stress fractures or pathologic fractures in low energy trauma or delayed healing of fractures. Presented is a case of a young adult male with Rothmund-Thomson syndrome presenting with multiple episodes of long bone fractures caused by low energy trauma with one of the fractures exhibiting significantly delayed healing. The patient was also found to have an asymptomatic stress fracture of the lower extremity, another finding of Rothmund-Thomson syndrome rarely reported in the literature. A thorough review of the literature and comprehensive presentation of Rothmund-Thomson syndrome is provided in conjunction with our case. PMID:26617641

  13. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    SciTech Connect

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; Doeppner, T.; Meyerhofer, D. D.; Murphy, C. D.; Sangster, T. C.; Vorberger, J.

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  14. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    DOE PAGES

    Regan, S. P.; Falk, K.; Gregori, G.; ...

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  15. A Robust Distributed Multipoint Fiber Optic Gas Sensor System Based on AGC Amplifier Structure

    PubMed Central

    Zhu, Cunguang; Wang, Rende; Tao, Xuechen; Wang, Guangwei; Wang, Pengpeng

    2016-01-01

    A harsh environment-oriented distributed multipoint fiber optic gas sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the distributed multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process. PMID:27483267

  16. Remote management for multipoint sensing systems using hetero-core spliced optical fiber sensors.

    PubMed

    Goh, Lee See; Anoda, Yuji; Kazuhiro, Watanabe; Shinomiya, Norihiko

    2013-12-27

    This paper describes the design and experimental verification of a multipoint sensing system with hetero-core spliced optical fiber sensors and its remote management using an internet-standard protocol. The study proposes two different types of design and conducts experiments to verify those systems' feasibility. In order to manage the sensing systems remotely, the management method uses a standard operation and maintenance protocol for internet: the Simple Network Management Protocol is proposed. The purpose of this study is to construct a multipoint sensing system remote management tool by which the system can also determine the status and the identity of fiber optic sensors. The constructed sensing systems are verified and the results have demonstrated that the first proposed system can distinguish the responses from different hetero-core spliced optical fiber sensors remotely. The second proposed system shows that data communications are performed successfully while identifying the status of hetero-core spliced optical fiber sensors remotely.

  17. A microsatellite-based multipoint index map of human chromosome 22

    SciTech Connect

    Buetow, K.H.; Duggan, D.; Yang, B.; Ludwigsen, S. ); Puck, J.; Porter, J.; Budarf, M.; Emanuel, B.S. ); Spielman, R. )

    1993-11-01

    Utilizing the CEPH (Centre d'Etude du Polymorphisme Humain) references panel and genotyping data for 24 simple tandem repeat polymorphism (STRP) markers, the authors have constructed a 15-locus multipoint genetic framework map of human chromosome 22. The markers form a continuous linkage group of 51 cM in males and 81 cM in females. Likely genetic locations are provided for 9 additional STRP sequences. The map was constructed employing the CRIMAP computational methodology to build the multipoint map via a stepwise algorithm. The quality of the framework map was evaluated using a battery of statistical diagnostics that suggest a typing error frequency of 0.1% for markers within the map. 27 refs., 3 figs., 3 tabs.

  18. Multi-point quasi-rational approximants for the modified Bessel function I1(x)

    NASA Astrophysics Data System (ADS)

    Martin, P.; Olivares, J.; Cortés-Vega, L.; Sotomayor, A.

    2016-08-01

    Approximants for the modified Bessel function I1(x) has been found using the multi-point quasi-rational technique. The approximations here determined has good accuracy for any positive value of the variable, and it seems to be adequate for most of the works where this function are used. Furthermore, the approximants are simple to calculate numerically in a direct way or using any usual MAPLE or MATLAB software.

  19. Initial operation of a pulse-burst laser system for high-repetition-rate Thomson scatteringa)

    NASA Astrophysics Data System (ADS)

    Harris, W. S.; Den Hartog, D. J.; Hurst, N. C.

    2010-10-01

    A pulse-burst laser has been installed for Thomson scattering measurements on the Madison Symmetric Torus reversed-field pinch. The laser design is a master-oscillator power-amplifier. The master oscillator is a commercial Nd:YVO4 laser (1064 nm) which is capable of Q-switching at frequencies between 5 and 250 kHz. Four Nd:YAG (yttrium aluminum garnet) amplifier stages are in place to amplify the Nd:YVO4 emission. Single pulses through the Nd:YAG amplifier stages gives energies up to 1.5 J and the gain for each stage has been measured. Repetitive pulsing at 10 kHz has also been performed for 2 ms bursts, giving average pulse energies of 0.53 J with ΔE /E of 4.6%, where ΔE is the standard deviation between pulses. The next step will be to add one of two Nd:glass (silicate) amplifier stages to produce final pulse energies of 1-2 J for bursts up to 250 kHz.

  20. Lasers As Particle Accelerators In Medicine: From Laser-Driven Protons To Imaging With Thomson Sources

    SciTech Connect

    Pogorelsky, I. V.; Babzien, M.; Polyanskiy, M. N.; Yakimenko, V.; Dover, N. P.; Palmer, C. A. J.; Najmudin, Z.; Shkolnikov, P.; Williams, O.; Rosenzweig, J.; Oliva, P.; Carpinelli, M.; Golosio, B.; Delogu, P.; Stefanini, A.; Endrizzi, M.

    2011-06-01

    We report our recent progress using a high-power, picosecond CO{sub 2} laser for Thomson scattering and ion acceleration experiments. These experiments capitalize on certain advantages of long-wavelength CO{sub 2} lasers, such as their high number of photons per energy unit and beneficial wavelength- scaling of the electrons' ponderomotive energy and critical plasma frequency. High X-ray fluxes produced in the interactions of the counter-propagating laser- and electron-beams for obtaining single-shot, high-contrast images of biological objects. The laser, focused on a hydrogen jet, generated a monoenergetic proton beam via the radiation-pressure mechanism. The energy of protons produced by this method scales linearly with the laser's intensity. We present a plan for scaling the process into the range of 100-MeV proton energy via upgrading the CO{sub 2} laser. This development will enable an advance to the laser-driven proton cancer therapy.

  1. Liquid hydrogen mass flow through a multiple orifice Joule-Thomson device

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Nyland, Ted W.; Saiyed, Naseem H.

    1992-01-01

    Liquid hydrogen mass flow rate, pressure drop, and temperature drop data were obtained for a number of multiple orifice Joule-Thomson devices known as visco jets. The present investigation continues a study to develop an equation for predicting two phase flow of cryogens through these devices. The test apparatus design allowed isenthalpic expansion of the cryogen through the visco jets. The data covered a range of inlet and outlet operating conditions. The mass flow rate range single phase or two phase was 0.015 to 0.98 lbm/hr. The manufacturer's equation was found to overpredict the single phase hydrogen data by 10 percent and the two phase data by as much as 27 percent. Two modifications of the equation resulted in a data correlation that predicts both the single and two phase flow across the visco jet. The first modification was of a theoretical nature, and the second strictly empirical. The former reduced the spread in the two phase data. It was a multiplication factor of 1-X applied to the manufacturer's equation. The parameter X is the flow quality downstream of the visco jet based on isenthalpic expansion across the device. The latter modification was a 10 percent correction term that correlated 90 percent of the single and two phase data to within +/- 10 percent scatter band.

  2. Rayleigh Scattering.

    ERIC Educational Resources Information Center

    Young, Andrew T.

    1982-01-01

    The correct usage of such terminology as "Rayleigh scattering,""Rayleigh lines,""Raman lines," and "Tyndall scattering" is resolved during an historical excursion through the physics of light-scattering by gas molecules. (Author/JN)

  3. Design of and data reduction from compact Thomson parabola spectrometers

    SciTech Connect

    Morrison, J. T.; Willis, C.; Freeman, R. R.; Van Woerkom, L.

    2011-03-15

    Thomson parabola spectrometers are used to characterize MeV ion beams produced in high intensity laser interactions. These spectrometers disperse multiple ion species according to their charge to mass ratio through the use of parallel electric and magnetic fields. Analytical solutions for ion deflection in electric and magnetic fields have been used to extract ion spectra with the assumption that fringing effects are negligible. Experimental space restrictions and dynamic range requirements necessitate designs that stress the analytical assumptions. Depending on design parameters, the error in the analytical assumption can be comparable to the energy resolution. Estimates are provided to approximate the error on the total ion deflection. A method for modeling ion trajectories including fringing effects is presented using software freely available or in common use. The magnetostatic fields are modeled in 3D, including material properties of nearby magnetic materials using RADIA. Electrostatic fields are modeled in 2D for a spectrometer implementing angled plates using the partial differential equation toolbox in MATLAB. Using these models to calculate the ion trajectory allows for analysis of a Thomson parabola spectrometer with an arbitrary field configuration.

  4. Events Leading to J. J. Thomson's Electron in 1897

    NASA Astrophysics Data System (ADS)

    Dahl, Per F.

    1997-03-01

    The electron had its genesis in the glow discharge studies of the German school of Julius Plucker and company, who viewed their Kathodenstrahlen as a form of aetheral wave propagation. Next on the scene came the Victorian amateur scientists, personified by the incomparable William Crookes, who interpreted the rays in terms of material particulate behavior. Back on the Continent, meanwhile, there was Heinrich Hertz and his disciple Philipp Lenard--the latter with his metallic ``window'' and all it stood for. In England, an experimental rivalry ensued between J. J. Thomson and Arthur Schuster, who nearly beat ``J.J.'' to his corpuscle in 1890, while in Paris, about then, Jean Perrin's cathode ray studies were provoked by the lingering anti-atomic stance of his academic countrymen. The chronicle culminated in the charge-to-mass experiments of 1896-97, in which Emil Wiechert and Walter Kaufmann narrowly missed the electron in favor of Thomson and his classic e/m determinations.

  5. Cytogenetic analysis in Rothmund-Thomson syndrome with osteosarcoma

    SciTech Connect

    Amar, M.; Sutphen, R.; Kousseff, B.G.

    1994-09-01

    Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive condition of poikiloderma, erythema, depigmentation, hyperpigmentation, musculoskeletal abnormalities and abnormalities of hair, teeth and nails. Osteogenic sacoma has been reported in 8 patients. Abnormal chromosome studies have been reported in only two patients. Chromosome analysis of tumor or bone marrow has not been reported. We performed cytogenetic studies on a patient with Rothmund-Thomson syndrome and osteogenic sarcoma. Analysis of peripheral lymphocytes revealed 46, XX karyotype by GTW banding. Both spontaneous and chemically-induced chromosome breakage (0.35 and 0.8 breaks/cell) were increased but not significantly different from the age-matched control levels (0.05 and 0.25 breaks/cell). Analysis of mitogen-stimulated bone marrow by Giemsa banding showed slightly increased aneuploidy (20% of cells with random loss of 1 to 5 chromosomes each) and non-specific chromatid despiralization. All 34 cells analyzed from the tumor had normal diploid karyotype, 46.XX. Five of 40 cells derived from skin of the amputated right leg were hyperdiploid with karyotype 47, XX, +7. Skin from the right forearm showed normal karyotype, 46,XX. These results suggest that RTS is associated with chromosomal rearrangement causing acquired somatic mosaicism, including trisomy 7 anomalies. These abnormalities may aid in the diagnosis of RTS and provide clues to the location of the causative gene(s).

  6. Use of near-infrared spectroscopy and multipoint measurements for quality control of pharmaceutical drug products.

    PubMed

    Boiret, Mathieu; Chauchard, Fabien

    2017-01-01

    Near-infrared (NIR) spectroscopy is a non-destructive analytical technique that enables better-understanding and optimization of pharmaceutical processes and final drug products. The use in line is often limited by acquisition speed and sampling area. This work focuses on performing a multipoint measurement at high acquisition speed at the end of the manufacturing process on a conveyor belt system to control both the distribution and the content of active pharmaceutical ingredient within final drug products, i.e., tablets. A specially designed probe with several collection fibers was developed for this study. By measuring spectral and spatial information, it provides physical and chemical knowledge on the final drug product. The NIR probe was installed on a conveyor belt system that enables the analysis of a lot of tablets. The use of these NIR multipoint measurement probes on a conveyor belt system provided an innovative method that has the potential to be used as a new paradigm to ensure the drug product quality at the end of the manufacturing process and as a new analytical method for the real-time release control strategy. Graphical abstract Use of near-infrared spectroscopy and multipoint measurements for quality control of pharmaceutical drug products.

  7. Joule-Thomson Cooling Due to CO2 Injection into Natural GasReservoirs

    SciTech Connect

    Oldenburg, Curtis M.

    2006-04-21

    Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling that accompanies the expansion of a real gas. If Joule-Thomson cooling were extreme, injectivity and formation permeability could be altered by the freezing of residual water,formation of hydrates, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. For verification of EOS7C, the classic Joule-Thomson expansion experiment is modeled for pure CO2 resulting in Joule-Thomson coefficients in agreement with standard references to within 5-7 percent. For demonstration purposes, CO2 injection at constant pressure and with a large pressure drop ({approx}50 bars) is presented in order to show that cooling by more than 20 C can occur by this effect. Two more-realistic constant-rate injection cases show that for typical systems in the Sacramento Valley, California, the Joule-Thomson cooling effect is minimal. This simulation study shows that for constant-rate injections into high-permeability reservoirs, the Joule-Thomson cooling effect is not expected to create significant problems for CSEGR.

  8. Coarsening kinetics, thermodynamic properties, and interfacial characteristics of δ' precipitates in Al-Li alloys taking into account the Gibbs-Thomson effect

    NASA Astrophysics Data System (ADS)

    Tsao, C.-S.; Chen, C.-Y.; Huang, J.-Y.

    2004-11-01

    The structure factor model of small-angle x-ray scattering (SAXS) analysis is validated herein by transmission electron microscopy (TEM) result regarding the volume fraction and size of δ' precipitates. The kinetic behaviors of the number density and volume fraction of δ' precipitates in Al-Li alloys during the coarsening stage are quantitatively investigated by SAXS. The results indicate that the conventional kinetic law must be replaced by a more general equation that incorporates the Gibbs-Thomson effect and the time-dependence of the volume fraction during Ostwald ripening. This work also proposes new methods that combine the Gibbs-Thomson effect and the traditional SAXS equation to resolve more reliably and model independently the interfacial energy, the concentration of solute Li in the α matrix in equilibrium with δ' particles of a nanoscale radius Cαr , the equilibrium solubility of the α phase Ceα and the equilibrium concentration of δ' particles. The Gibbs-Thomson effect considers the effects of the interfacial energy and particle size on the equilibrium concentration. This effect quantitatively clarifies that the Cαr value is size-dependent and is related to the Ceα value and the interfacial energy. The traditional SAXS equation determines the Li concentrations in the δ' particles and the matrix from the measured scattering contrast. The traditionally determined solubility is in fact the Cαr value and is mistakenly regarded as the equilibrium concentration Ceα (corresponding to the radius is infinite). These results are compared to other results obtained by SAXS, TEM, and calculation. The time evolution of the transition interfacial layers between δ' particles and the matrix is extensively investigated using SAXS.

  9. Application of vanadium hydride compressors for Joule-Thomson cryocoolers

    NASA Astrophysics Data System (ADS)

    Bowman, R. C., Jr.; Freeman, B. D.; Phillips, J. R.

    The Joule-Thomson expansion of hydrogen gas offers efficient and reliable cryocoolers to produce temperatures between 10 and 50 K. A critical component to the development of these devices is the metal hydride storage bed that provides a nonmechanical method to compress hydrogen gas via the reversible absorption by appropriate metals or alloys. A thermodynamic model has been used to calculate the impact of operational parameters such as input/output pressure ratios and bed temperature on energy balance and system efficiency. Detailed comparisons are reported for a compressor which utilizes vanadium metal as the sorbent for either hydrogen or deuterium where the unusually large isotope differences between the phase diagrams and thermal properties for VH(x) and VD(x) have been considered. The sensitivity of heat input requirements to the uncertainties in primary variables are described.

  10. Fluctuations and Gibbs-Thomson Law - the Simple Physics.

    SciTech Connect

    Chernov, A A; De Yoreo, J J; Rashkovich, L N

    2006-09-15

    Crystals of slightly soluble materials should be subject of relatively weak attachment/detachment fluctuations on their faces so that steps on that faces have low kink density. These steps are parallel to the most close packed lattice rows and form polygons on a crystal surface. The process responsible for implementation of the classical Gibbs-Thomson law (GTL) for the polygonal step (in two dimensions, 2D) is kink exchange between the step corners. For the 3D crystallites, this mechanism includes step exchange. If these mechanisms do not operate because of slow fluctuations the GTL is not applicable. Physics of these processes and conditions for the GTL applicability are discussed on a simple qualitative level.

  11. Gibbs-Thomson effect in nanocrystalline Fe-Ge

    NASA Astrophysics Data System (ADS)

    Sarkar, S.; Bansal, C.; Chatterjee, Ashok

    2000-08-01

    We studied the phase transformation behavior of chemically disordered bcc (α) phase Fe1-xGex alloys near the Fe3Ge stoichiometry synthesized in the nanocrystalline state by mechanical alloying of the elemental constituents. The evolution of the equilibrium L12 ordered (ɛ') phase was seen to occur via a metastable DO3-ordered (α1) phase, but a significant α1-->ɛ' phase transformation took place only after the growth of the grains. This behavior is understood with the help of a capillary effect or the Gibbs-Thomson effect wherein the grain boundary energy of the nanosize grains raises the Gibbs free energy of the ɛ' phase relative to the α1 phase for small sizes and the ɛ' phase grows only after a certain grain size is reached.

  12. Joule-Thomson cryogenic cooler with extremely high thermal stability

    NASA Technical Reports Server (NTRS)

    Bard, Steven; Wu, J. J.; Trimble, Curt

    1991-01-01

    An 80-K Joule-Thomson (J-T) cooling system designed for the Probe Infrared Laser Spectrometer (PIRLS) proposed for the Huygens Titan Probe of the Cassini Saturn orbiter mission is presented. The cryogenic cooling requirements of the PIRLS instrument are listed, and the cooler system design including details of a J-T cryostat, cold head, and dewar design is described along with the results of a thermal modeling effort and lab cooler performance testing. It is shown that by using active feedback temperature control of the cold head in combination with the self-regulating action of the J-T cryostat, a temperature stability of less than 0.1 mK/min is achieved by the cooler weighting 1.8 kg.

  13. Comment on "Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping"

    NASA Astrophysics Data System (ADS)

    Terzić, Balša; Krafft, Geoffrey A.

    2016-09-01

    Rykovanov, Geddes, Schroeder, Esarey and Leemans [Phys. Rev. Accel. Beams 19, 030701 (2016), 10.1103/PhysRevAccelBeams.19.030701; hereafter RGSEL] have recently reported on the analytic derivation for the laser pulse frequency modulation (chirping) which controls spectrum broadening for high laser pulse intensities. We demonstrate here that their results are the same as the exact solutions reported in Terzić, Deitrick, Hofler and Krafft [Phys. Rev. Lett. 112, 074801 (2014), 10.1103/PhysRevLett.112.074801; hereafter TDHK]. While the two papers deal with circularly and linearly polarized laser pulses, respectively, the difference in expressions for the two is just the usual factor of 1 /2 present from going from circular to linear polarization. In addition, we note the authors used an approximation to the number of subsidiary peaks in the unchirped spectrum when a better solution is given in TDHK.

  14. A study of optical scattering methods in laboratory plasma diagnosis

    NASA Technical Reports Server (NTRS)

    Phipps, C. R., Jr.

    1972-01-01

    Electron velocity distributions are deduced along axes parallel and perpendicular to the magnetic field in a pulsed, linear Penning discharge in hydrogen by means of a laser Thomson scattering experiment. Results obtained are numerical averages of many individual measurements made at specific space-time points in the plasma evolution. Because of the high resolution in k-space and the relatively low maximum electron density 2 x 10 to the 13th power/cu cm, special techniques were required to obtain measurable scattering signals. These techniques are discussed and experimental results are presented.

  15. Thomson Scientific's expanding Web of Knowledge: beyond citation databases and current awareness services.

    PubMed

    London, Sue; Brahmi, Frances A

    2005-01-01

    As end-user demand for easy access to electronic full text continues to climb, an increasing number of information providers are combining that access with their other products and services, making navigating their Web sites by librarians seeking information on a given product or service more daunting than ever. One such provider of a complex array of products and services is Thomson Scientific. This paper looks at some of the many products and tools available from two of Thomson Scientific's businesses, Thomson ISI and Thomson ResearchSoft. Among the items of most interest to health sciences and veterinary librarians and their users are the variety of databases available via the ISI Web of Knowledge platform and the information management products available from ResearchSoft.

  16. A Virial Treatment of the Joule and Joule-Thomson Coefficients.

    ERIC Educational Resources Information Center

    Rybolt, Thomas R.

    1981-01-01

    Provides background information designed to aid a physical chemistry student in using the virial equation of state in deriving expressions for other thermodynamic properties, such as writing the Joule and Joule-Thomson coefficients in terms of virial expansions. (CS)

  17. Theoretical calculation of Joule-Thomson coefficient by using third virial coefficient

    NASA Astrophysics Data System (ADS)

    Mamedov, Bahtiyar Akber; Somuncu, Elif; Askerov, Iskender M.

    2017-02-01

    The Joule-Thomson coefficient has been theoretical investigated by using third virial coefficient. Established expressions enable us accurate and rapid calculations of Joule-Thomson coefficient. As seen from numerical results the analytical expressions for third virial coefficients are a very useful, giving a very fast method to calculate other thermodynamics properties of gasses. As an example, the calculation results have been successfully tested by using various literature data.

  18. Multipoint identity-by-descent computations for single-point polymorphism and microsatellite maps.

    PubMed

    Hinrichs, Anthony L; Bertelsen, Sarah; Bierut, Laura J; Dunn, Gerald; Jin, Carol H; Kauwe, John S; Suarez, Brian K

    2005-12-30

    We used the LOKI software to generate multipoint identity-by-descent matrices for a microsatellite map (with 31 markers) and two single-nucleotide polymorphism (SNP) maps to examine information content across chromosome 7 in the Collaborative Study on the Genetics of Alcoholism dataset. Despite the lower information provided by a single SNP, SNP maps overall had higher and more uniform information content across the chromosome. The Affymetrix map (578 SNPs) and the Illumina map (271 SNPs) provided almost identical information. However, increased information has a computational cost: SNP maps require 100 times as many iterations as microsatellites to produce stable estimates.

  19. The network and transmission of based on the principle of laser multipoint communication

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Liu, Xianzhu; Jiang, Huilin; Hu, Yuan; Jiang, Lun

    2014-11-01

    Space laser communication is the perfectly choose to the earth integrated information backbone network in the future. This paper introduces the structure of the earth integrated information network that is a large capacity integrated high-speed broadband information network, a variety of communications platforms were densely interconnected together, such as the land, sea, air and deep air users or aircraft, the technologies of the intelligent high-speed processing, switching and routing were adopt. According to the principle of maximum effective comprehensive utilization of information resources, get accurately information, fast processing and efficient transmission through inter-satellite, satellite earth, sky and ground station and other links. Namely it will be a space-based, air-based and ground-based integrated information network. It will be started from the trends of laser communication. The current situation of laser multi-point communications were expounded, the transmission scheme of the dynamic multi-point between wireless laser communication n network has been carefully studied, a variety of laser communication network transmission schemes the corresponding characteristics and scope described in detail , described the optical multiplexer machine that based on the multiport form of communication is applied to relay backbone link; the optical multiplexer-based on the form of the segmentation receiver field of view is applied to small angle link, the optical multiplexer-based form of three concentric spheres structure is applied to short distances, motorized occasions, and the multi-point stitching structure based on the rotation paraboloid is applied to inter-satellite communications in detail. The multi-point laser communication terminal apparatus consist of the transmitting and receiving antenna, a relay optical system, the spectroscopic system, communication system and communication receiver transmitter system. The communication forms of optical

  20. Plasmaspheric ion temperature dynamics related to ionospheric and ring current parameter variations: Multipoint observations

    NASA Astrophysics Data System (ADS)

    Kotova, Galina; Bezrukikh, Vladilen; Verigin, Mikhael

    Thermal plasma measurements on INTERBALL 2 (1996) and its subsatellite MAGION 5 (1999 - 2001) are used to deduce proton temperature and density distributions in the Earth's plasmasphere. A study of the temperature behavior during moderate magnetic storms development revealed that in the inner plasmasphere (L ¡ 2.8) night time ion temperature was depressed in the storm main phase, but exceeded quiet time values in the storm recovery phase. Multipoint observations in the plasmasphere, ionosphere (DMSP) and magnetosphere (IMAGE, POLAR) are used for examining possible reasons of such temperature behavior. This work was partially supported by Programs P16/2 and OFN 16 of Russian Academy of Sciences.

  1. Multipoint oligogenic analysis of age-at-onset data with applications to Alzheimer disease pedigrees.

    PubMed Central

    Daw, E W; Heath, S C; Wijsman, E M

    1999-01-01

    It is usually difficult to localize genes that cause diseases with late ages at onset. These diseases frequently exhibit complex modes of inheritance, and only recent generations are available to be genotyped and phenotyped. In this situation, multipoint analysis using traditional exact linkage analysis methods, with many markers and full pedigree information, is a computationally intractable problem. Fortunately, Monte Carlo Markov chain sampling provides a tool to address this issue. By treating age at onset as a right-censored quantitative trait, we expand the methods used by Heath (1997) and illustrate them using an Alzheimer disease (AD) data set. This approach estimates the number, sizes, allele frequencies, and positions of quantitative trait loci (QTLs). In this simultaneous multipoint linkage and segregation analysis method, the QTLs are assumed to be diallelic and to interact additively. In the AD data set, we were able to localize correctly, quickly, and accurately two known genes, despite the existence of substantial genetic heterogeneity, thus demonstrating the great promise of these methods for the dissection of late-onset oligogenic diseases. PMID:10053019

  2. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lyon, Elliott; Kuang, Zheng; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2014-11-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion - a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed.

  3. A multi-point laser Doppler vibrometer with fiber-based configuration

    SciTech Connect

    Yang, C.; Guo, M.; Liu, H.; Yan, K.; Xu, Y. J.; Fu, Y.; Miao, H.

    2013-12-15

    Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration, it becomes more practical for dynamic structural evaluation in industrial areas.

  4. Space Technology 5 Multipoint Observations of Temporal and Spatial Variability of Field-Aligned Currents

    NASA Technical Reports Server (NTRS)

    Le, G.; Wang, Y.; Slavin, J. A.; Strangeway, R. L.

    2009-01-01

    Space Technology 5 (ST5) is a constellation mission consisting of three microsatellites. It provides the first multipoint magnetic field measurements in low Earth orbit, which enables us to separate spatial and temporal variations. In this paper, we present a study of the temporal variability of field-aligned currents using the ST5 data. We examine the field-aligned current observations during and after a geomagnetic storm and compare the magnetic field profiles at the three spacecraft. The multipoint data demonstrate that mesoscale current structures, commonly embedded within large-scale current sheets, are very dynamic with highly variable current density and/or polarity in approx.10 min time scales. On the other hand, the data also show that the time scales for the currents to be relatively stable are approx.1 min for mesoscale currents and approx.10 min for large-scale currents. These temporal features are very likely associated with dynamic variations of their charge carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of mesoscale field-aligned currents are found to be consistent with those of auroral parallel electric field.

  5. Highly sensitive multipoint real-time kinetic detection of Surface Plasmon bioanalytes with custom CMOS cameras.

    PubMed

    Wang, Jing; Smith, Richard J; Light, Roger A; Richens, Joanna L; Zhang, Jing; O'Shea, Paul; See, Chung; Somekh, Michael G

    2014-08-15

    Phase sensitive Surface Plasmon Resonance (SPR) techniques are a popular means of characterizing biomolecular interactions. However, limitations due to the narrow dynamic range and difficulty in adapting the method for multi-point sensing have restricted its range of applications. This paper presents a compact phase sensitive SPR technology using a custom CMOS camera. The system is exceptionally versatile enabling one to trade dynamic range for sensitivity without altering the optical system. We present results showing sensitivity over the array of better than 10(-6) Refractive Index Units (RIU) over a refractive index range of 2×10(-2)RIU, with peak sensitivity of 3×10(-7)RIU at the center of this range. We also explain how simply altering the settings of polarization components can give sensitivity on the order of 10(-8)RIU albeit at the cost of lower dynamic range. The consistent response of the custom CMOS camera in the system also allowed us to demonstrate precise quantitative detection of two Fibrinogen antibody-protein binding sites. Moreover, we use the system to determine reaction kinetics and argue how the multipoint detection gives useful insight into the molecular binding mechanisms.

  6. Resolution comparison of continuous and multipoint line ORVIS for periodic and aperiodic features

    NASA Astrophysics Data System (ADS)

    Furnish, Michael

    2017-01-01

    For both conventional (continuous image) and 60-point Line ORVIS or VISAR, data records were synthesized for several classes of interesting problems. These included ridged impactors (periodic velocity structure) and pore crushup (isolated structure), and were constructed by directly importing CTH tracer velocity histories. These records were then analyzed using Fourier Transform and fringe-trace methods (continuous image) or point-by-point quadrature reduction (60-point system), and the results were compared to learn about system spatial resolution. A conventional Line VISAR with n fringes across the field of view has spatial resolution roughly equivalent to a 2n-point multipoint instrument. The actual usable number of fringes depends on surface preparation, relay quality, and other factors. For the 60-point, there may be more robustness to surface preparation, but an experience base is not in-hand yet. In particular, surface tilt effect depends on probe particulars. Either type of system (multipoint or continuous line) can usefully diagnose a wide variety of problems.

  7. Online system for faster multipoint linkage analysis via parallel execution on thousands of personal computers.

    PubMed

    Silberstein, M; Tzemach, A; Dovgolevsky, N; Fishelson, M; Schuster, A; Geiger, D

    2006-06-01

    Computation of LOD scores is a valuable tool for mapping disease-susceptibility genes in the study of Mendelian and complex diseases. However, computation of exact multipoint likelihoods of large inbred pedigrees with extensive missing data is often beyond the capabilities of a single computer. We present a distributed system called "SUPERLINK-ONLINE," for the computation of multipoint LOD scores of large inbred pedigrees. It achieves high performance via the efficient parallelization of the algorithms in SUPERLINK, a state-of-the-art serial program for these tasks, and through the use of the idle cycles of thousands of personal computers. The main algorithmic challenge has been to efficiently split a large task for distributed execution in a highly dynamic, nondedicated running environment. Notably, the system is available online, which allows computationally intensive analyses to be performed with no need for either the installation of software or the maintenance of a complicated distributed environment. As the system was being developed, it was extensively tested by collaborating medical centers worldwide on a variety of real data sets, some of which are presented in this article.

  8. Characterization of a thermoelectric/Joule-Thomson hybrid microcooler

    NASA Astrophysics Data System (ADS)

    Cao, H. S.; Vanapalli, S.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.

    2016-07-01

    Micromachined Joule-Thomson (JT) coolers are attractive for cooling small electronic devices. However, microcoolers operated with pure gases, such as nitrogen gas require high pressures of about 9 MPa to achieve reasonable cooling powers. Such high pressures severely add complexity to the development of compressors. To overcome this disadvantage, we combined a JT microcooler with a thermoelectric (TE) pre-cooler to deliver an equivalent cooling power with a lower pressure or, alternatively, a higher cooling power when operating with the same pressure. This hybrid microcooler was operated with nitrogen gas as the working fluid at a low pressure of 0.6 MPa. The cooling power of the microcooler at 101 K operating with a fixed high pressure of 8.8 MPa increased from 21 to 60 mW when the precooling temperature was reduced by the thermoelectric cooler from 295 to 250 K. These tests were simulated using a dynamic numerical model and the accuracy of the model was verified through the comparison between experimental and simulation results. Based on the model, we found the high pressure of the microcooler can be reduced from 8.8 to 5.5 MPa by lowering the precooling temperature from 295 to 250 K. Moreover, the effect of TE cooler position on the performance of the hybrid microcooler was evaluated through simulation analysis.

  9. High-resolution Thomson parabola for ion analysis

    NASA Astrophysics Data System (ADS)

    Cobble, J. A.; Flippo, K. A.; Offermann, D. T.; Lopez, F. E.; Oertel, J. A.; Mastrosimone, D.; Letzring, S. A.; Sinenian, N.

    2011-11-01

    A new, versatile Thomson parabola ion energy (TPIE) analyzer has been designed, constructed, and used at the OMEGA-EP facility. Laser-accelerated multi-MeV ions from hemispherical C targets are transmitted through a W pinhole into a multi-kG magnetic field and subsequently through a parallel electric field of up to 25 kV/cm. The ion drift region has a user-selected length of 10, 50, or 80 cm. With the highest fields, 400-MeV C6+ and C5+ may be resolved. TPIE is ten-inch manipulator (TIM)-mounted at OMEGA-EP and can be used opposite either of the EP ps beams. The instrument runs on pressure-interlocked 15-Vdc power available in EP TIM carts. Flux control derives from the insertion depth into the target chamber and the user-selected pinhole dimensions. The detector consists of CR39 backed by an image plate. A fully relativistic simulation code for calculating ion trajectories was employed for design optimization. Excellent agreement of code predictions with the actual ion positions on the detectors is observed. Through pit counting of carbon-ion tracks in CR39, it is shown that conversion efficiency of laser light to energetic carbon ions exceeds ˜5% for these targets.

  10. Joule-Thomson microcooling developments at University of Twente

    NASA Astrophysics Data System (ADS)

    Cao, H. S.; Vanapalli, S.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.; Lerou, P. P. P. M.; Tirolien, T.

    2017-02-01

    The development of Joule-Thomson microcoolers has been an on-going and successful research project at the University of Twente for many years. The aim of the research is to develop small and fully integrated cryogenic cooling systems for cooling small electronic devices such as pre-amplifiers and infrared sensors, in order to improve their performance. In the foregoing years, we have successfully developed single-stage microcoolers (typically cooling to 100 K) and two-stage microcoolers (typically 30 K) using standard micromachining technologies. In the present paper, we emphatically discuss recent developments in the Twente microcooling project among which microcoolers with a double expansion of the high pressure flow (reducing the 100 K to 83 K operating temperature), microcoolers operating with hydrocarbon gas mixtures, and microcoolers with an ejector, the three new developments aiming at lower cold end temperatures, lower operating pressure ratios and/or higher efficiency. Besides, utilization of microcoolers for cooling electronics and clogging phenomenon in microcoolers will also be introduced.

  11. Analysis of two-stage Joule-Thomson expansion

    NASA Astrophysics Data System (ADS)

    Narasaki, Katsuhiro

    2016-03-01

    To cool far infrared detectors for infrared observation or superconductor-insulator-superconductor (SIS) mixers for atmospheric observation, 1 K-class and 4 K-class coolers have been developed. These coolers consist of a two-stage Stirling cooler for pre-cooling and a Joule-Thomson (JT) cooler with a single JT valve. This paper presents descriptions of theoretical analyses based on enthalpy balance to elucidate the benefits of a two-stage JT valve type compared with those of a single JT valve type in a JT cooler. First, relational expressions for heat balance analysis of enthalpy for single-stage JT expansion are introduced. Then similar relational expressions for two-stage JT expansion are introduced under some assumptions. Results of heat balance analyses using several parameters demonstrated that, using two-stage JT expansion, the cooling capacity for a 1 K-class cooler is improved by 100%; that of a 4 K-class cooler is improved by about 30%.

  12. Apparent Inverse Gibbs-Thomson Effect in Dealloyed Nanoporous Nanoparticles

    NASA Astrophysics Data System (ADS)

    McCue, I.; Snyder, J.; Li, X.; Chen, Q.; Sieradzki, K.; Erlebacher, J.

    2012-06-01

    The Gibbs-Thomson effect (the reduction of local chemical potential due to nanoscale curvature) predicts that nanoparticles of radius r dissolve at lower electrochemical potentials than bulk materials, decreasing as 1/r. However, we show here that if the particle is an alloy—susceptible to selective dissolution (dealloying) and nanoporosity evolution—then complete selective electrochemical dissolution and porosity evolution require a higher electrochemical potential than the comparable bulk planar material, increasing empirically as 1/r. This is a kinetic effect, which we demonstrate via kinetic Monte Carlo simulation. Our model shows that in the initial stages of dissolution, the less noble particle component is easily stripped from the nanoparticle surface, but owing to an increased mobility of the more noble atoms, the surface of the particle quickly passivates. At a fixed electrochemical potential, porosity and complete dealloying can only evolve if fluctuations in the surface passivation layer are sufficiently long-lived to allow dissolution from percolating networks of the less-noble component that penetrate through the bulk of the particle.

  13. Apparent inverse Gibbs-Thomson effect in dealloyed nanoporous nanoparticles.

    PubMed

    McCue, I; Snyder, J; Li, X; Chen, Q; Sieradzki, K; Erlebacher, J

    2012-06-01

    The Gibbs-Thomson effect (the reduction of local chemical potential due to nanoscale curvature) predicts that nanoparticles of radius r dissolve at lower electrochemical potentials than bulk materials, decreasing as 1/r. However, we show here that if the particle is an alloy--susceptible to selective dissolution (dealloying) and nanoporosity evolution--then complete selective electrochemical dissolution and porosity evolution require a higher electrochemical potential than the comparable bulk planar material, increasing empirically as 1/r. This is a kinetic effect, which we demonstrate via kinetic Monte Carlo simulation. Our model shows that in the initial stages of dissolution, the less noble particle component is easily stripped from the nanoparticle surface, but owing to an increased mobility of the more noble atoms, the surface of the particle quickly passivates. At a fixed electrochemical potential, porosity and complete dealloying can only evolve if fluctuations in the surface passivation layer are sufficiently long-lived to allow dissolution from percolating networks of the less-noble component that penetrate through the bulk of the particle.

  14. Improving Control in a Joule-Thomson Refrigerator

    NASA Technical Reports Server (NTRS)

    Borders, James; Pearson, David; Prina, Mauro

    2005-01-01

    A report discusses a modified design of a Joule-Thomson (JT) refrigerator under development to be incorporated into scientific instrumentation aboard a spacecraft. In most other JT refrigerators (including common household refrigerators), the temperature of the evaporator (the cold stage) is kept within a desired narrow range by turning a compressor on and off as needed. This mode of control is inadequate for the present refrigerator because a JT-refrigerator compressor performs poorly when the flow from its evaporator varies substantially, and this refrigerator is required to maintain adequate cooling power. The proposed design modifications include changes in the arrangement of heat exchangers, addition of a clamp that would afford a controlled heat leak from a warmer to a cooler stage to smooth out temperature fluctuations in the cooler stage, and incorporation of a proportional + integral + derivative (PID) control system that would regulate the heat leak to maintain the temperature of the evaporator within a desired narrow range while keeping the amount of liquid in the evaporator within a very narrow range in order to optimize the performance of the compressor. Novelty lies in combining the temperature- and cooling-power-regulating controls into a single control system.

  15. Ionospheric Cubeswarm Concept Study: using low-resource instrumentation for truly multipoint in situ ionospheric observations

    NASA Astrophysics Data System (ADS)

    Hampton, D.; Lynch, K. A.; Earle, G. D.; Mannucci, A. J.; Clayton, R.; Fisher, L. E.; Fernandes, P. A.; Roberts, M.; Zettergren, M. D.

    2015-12-01

    Magnetosphere-ionosphere coupling currents close in the nightside lower ionosphere. These spatially inhomogeneous and time varying volume currents are difficult to capture with in situ observations. Our understanding of M-I coupling systems is limited by our understanding of the actual structure of ionospheric current closure. A path forward includes assimilation of a variety of data sets into increasingly capable ionospheric models. While each data set provides only a piece of the picture, the assimilation process allows optimal use of each piece.An important development for the necessary in situ observations involves making them truly multi-point, and therefore, low-resource. For thermal particle observations, the high densities of the lower ionosphere allow the use of low-gain (current-sensing rather than particle-counting) particle sensors. One observational goal is the definition of the actual structure of ionospheric closure currents. This can be approached with a number of different measurement techniques, in tandem with an ionospheric model, since the closure currents need to follow the rules of electrodynamics and current continuity. Low resource thermal plasma sensors such as retarding potential analyzers and drift meters can provide valuable measurements of plasma parameters, including density and plasma flow, without the need for high voltages or deployable boom systems. These low-resource measurements, which can be reproduced on arrays of in situ observation platforms, used in tandem with proper plasma physics interpretation of their signatures in the disturbed observing environment, and as part of an assimilated data set into an ionospheric model, can allow us to progress in our understanding of ionospheric structuring and its effects on auroral coupling. Now, with increasingly capable multipoint arrays of spacecraft, and quantitative 2D-with-time context from cameras and imagery, we are moving toward truly multipoint studies of the system

  16. Multipoint NIR spectroscopy for gross composition analysis of powdered infant formula under various motion conditions.

    PubMed

    Cama-Moncunill, Raquel; Markiewicz-Keszycka, Maria; Dixit, Yash; Cama-Moncunill, Xavier; Casado-Gavalda, Maria P; Cullen, Patrick J; Sullivan, Carl

    2016-07-01

    Powdered infant formula (PIF) is a worldwide, industrially produced, human milk substitute. Manufacture of PIF faces strict quality controls in order to ensure that the product meets all compositional requirements. Near-infrared (NIR) spectroscopy is a rapid, non-destructive and well-qualified technique for food quality assessments. The use of fibre-optic NIR sensors allows measuring in-line and at real-time, and can record spectra from different stages of the process. The non-contact character of fibre-optic sensors can be enhanced by fitting collimators, which allow operation at various distances. The system, based on a Fabry-Perot interferometer, records four spectra concurrently, rather than consecutively as in the "quasi-simultaneous" multipoint NIR systems. In the present study, a novel multipoint NIR spectroscopy system equipped with four fibre-optic probes with collimators was assessed to determine carbohydrate and protein contents of PIF samples under static and motion conditions (0.02, 0.15 and 0.30m/s) to simulate possible industrial scenarios. Best results were obtained under static conditions providing a R(2) of calibration of 0.95 and RMSEP values of 1.89%. Yet, considerably low values of RMSEP, for instance 2.70% at 0.15m/s, were provided with the in-motion predictions, demonstrating the system's potential for in/on-line applications at various levels of speed. The current work also evaluated the viability of using general off-line calibrations developed under static conditions for on/in-line applications subject to motion. To this end, calibrations in both modes were developed and compared. Best results were obtained with specific calibrations; however, reasonably accurate models were obtained with the general calibration. Furthermore, this work illustrated independency of the collimator-probe setup by characterizing PIF samples simultaneously recorded according to their carbohydrate content, even when measured under different conditions. Therefore

  17. A new lease of life for Thomson's bonds model of intelligence.

    PubMed

    Bartholomew, David J; Deary, Ian J; Lawn, Martin

    2009-07-01

    Modern factor analysis is the outgrowth of Spearman's original "2-factor" model of intelligence, according to which a mental test score is regarded as the sum of a general factor and a specific factor. As early as 1914, Godfrey Thomson realized that the data did not require this interpretation and he demonstrated this by proposing what became known as his "bonds" model of intelligence. Van der Maas et al. (2006) have recently drawn attention to what they perceive as difficulties with both models and have proposed a 3rd model. Neither alternative requires the general factor that was at the core of Spearman's idea. Although Thomson's model has been largely forgotten, the authors show that it merits further consideration because it can compete, statistically and biologically, on equal terms with Spearman's model. In particular, they show that it is impossible to distinguish statistically between the 2 models. There are also lessons to be learnt from the way in which Thomson arrived at his model and from the subsequent debate between Spearman and Thomson. The extent to which the recent proposal by van der Maas et al. may offer any advantage over Spearman's and Thomson's models is unclear and requires further investigation.

  18. Effects of environmental temperature on performance of the Joule-Thomson refrigerator

    NASA Astrophysics Data System (ADS)

    Hong, Yong-Ju; Kim, Hyobong; Park, Seong-Je

    2012-06-01

    Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. Typical performance factors of the Joule-Thomson refrigerator are cool-down time, temperature of the cold end, running time and gas consumption. Those depend on operating conditions such as the pressure of the gas, thermal environment and etc.. In this study, experimental study of a miniature Joule- Thomson refrigerator with the gas pressure up to 12 MPa were performed to investigate the effects of the thermal environment (-40 ~ 50 °C). In experiments, to obtain the information of cool-down time, gas consumption and etc., the temperature of the cold end, mass flow rate and pressure of the argon gas are simultaneously measured. The Joule-Thomson refrigerator in cold thermal environment has rapid cool-down characteristics and small gas consumption. In the cold environmental condition, the Joule-Thomson refrigerator has high mass flow rate during cool-down process and in steady state.

  19. Construction of Joule Thomson inversion curves for mixtures using equation of state

    NASA Astrophysics Data System (ADS)

    Patankar, A. S.; Atrey, M. D.

    2017-02-01

    The Joule-Thomson effect is at the heart of Joule-Thomson cryocoolers and gas liquefaction cycles. The effective harnessing of this phenomenon necessitates the knowledge of Joule-Thomson coefficient and the inversion curve. When the working fluid is a mixture, (in mix refrigerant Joule-Thomson cryocooler, MRJT) the phase diagrams, equations of state and inversion curves of multi-component systems become important. The lowest temperature attainable by such a cryocooler depends on the inversion characteristics of the mixture used. In this work the construction of differential Joule-Thomson inversion curves of mixtures using Redlich-Kwong, Soave-Redlich-Kwong and Peng-Robinson equations of state is investigated assuming single phase. It is demonstrated that inversion curves constructed for pure fluids can be improved by choosing an appropriate value of acentric factor. Inversion curves are used to predict maximum inversion temperatures of multicomponent systems. An application where this information is critical is a two-stage J-T cryocooler using a mixture as the working fluid, especially for the second stage. The pre-cooling temperature that the first stage is required to generate depends on the maximum inversion temperature of the second stage working fluid.

  20. Statistical thermodynamics of aerosols and the gas-solid Joule-Thomson effect

    NASA Astrophysics Data System (ADS)

    Pierotti, Robert A.; Rybolt, Thomas R.

    1984-04-01

    Due to the adsorption of a gas by a solid, it is expected that an aerosol created by dispersing a fine powder in a gas would have unique thermodynamic properties not found in pure or mixed gases. The virial equation of state associated with an aerosol dusty gas is obtained from statistical thermodynamic considerations. In the theoretical model presented here, the aerosol is considered to be a two component fluid made up of solid particles and gas molecules. The aerosol virial equation of state is used to derive an expression for the Joule-Thomson effect associated with a gas-solid dispersion. The magnitude of the gas-solid Joule-Thomson effect is expressed in terms of gas and gas-solid virial coefficients. Previous adsorption data for an argon-porous carbon system is used to obtain gas-solid virial coefficients and to predict the magnitude of the gas-solid Joule-Thomson effect. A significant enhancement of the Joule-Thomson effect is predicted for gas-solid systems which display a strong interaction. For example, at a temperature of 300 K an argon-Saran 746 porous carbon aerosol system at a concentration of (0.4 g of powder/l of gas) is predicted to have a gas-solid Joule-Thomson coefficient of 3.6 K/atm which is ten times greater than the effect for pure argon.

  1. Godfrey Thomson and the Rise of University Pedagogical Study: A Recorded Lecture Delivered at the University of Edinburgh in November 1950 by Godfrey H. Thomson--A Transcript with Commentary

    ERIC Educational Resources Information Center

    Lawn, Martin; Deary, Ian J.; Brett, Caroline; Bartholomew, David J.

    2009-01-01

    Professor Sir Godfrey Thomson is one of the key foundational actors in the history of the educational sciences in the UK. At a time when educational studies and the study of educational psychology were very closely linked, in the decades of the mid-twentieth century, Thomson was a crucial figure in education research. He is known for his work on…

  2. Clogging of Joule-Thomson Devices in Liquid Hydrogen Handling

    NASA Technical Reports Server (NTRS)

    Jurns, John M.; Lekki, John D.

    2009-01-01

    Experiments conducted at the NASA Glenn Research Center indicate that Joule-Thomson devices become clogged when transferring liquid hydrogen (LH2), operating at a temperature range from 20.5 to 24.4 K. Blockage does not exist under all test conditions but is found to be sensitive to the inlet temperature of the LH2. At a subcooled inlet temperature of 20.5 K blockage consistently appears but is dissipated when the fluid temperature is raised above 24.5 K. Clogging steadily reduced flow rate through the orifices, eventually resulting in complete blockage. This tendency poses a threat to spacecraft cryogenic propulsion systems that would utilize passive thermal control systems. We propose that this clogging is due to trace amounts of neon in the regular LH2 supply. Neon freezes at 24.5 K at one atmosphere pressure. It is postulated that between 20.5 and 24.5 K, neon remains in a meta-stable, supercooled liquid state. When impacting the face of an orifice, liquid neon droplets solidify and accumulate, blocking flow over time. The purpose of this test program was to definitively quantify the phenomena experimentally by obtaining direct visual evidence of orifice clogging by accretion from neon contaminates in the LH2 flow stream, utilizing state of the art imaging technology. Tests were conducted with LH2 flowing in the temperature range of 20.5 to 24.4 K. Additional imaging was also done at LH2 temperatures with no flow to verify clear view through the orifice.

  3. A synchronized multipoint vision-based system for displacement measurement of civil infrastructures.

    PubMed

    Ho, Hoai-Nam; Lee, Jong-Han; Park, Young-Soo; Lee, Jong-Jae

    2012-01-01

    This study presents an advanced multipoint vision-based system for dynamic displacement measurement of civil infrastructures. The proposed system consists of commercial camcorders, frame grabbers, low-cost PCs, and a wireless LAN access point. The images of target panels attached to a structure are captured by camcorders and streamed into the PC via frame grabbers. Then the displacements of targets are calculated using image processing techniques with premeasured calibration parameters. This system can simultaneously support two camcorders at the subsystem level for dynamic real-time displacement measurement. The data of each subsystem including system time are wirelessly transferred from the subsystem PCs to master PC and vice versa. Furthermore, synchronization process is implemented to ensure the time synchronization between the master PC and subsystem PCs. Several shaking table tests were conducted to verify the effectiveness of the proposed system, and the results showed very good agreement with those from a conventional sensor with an error of less than 2%.

  4. Approaching Solar Maximum 24 with Stereo-Multipoint Observations of Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Dresing, N.; Cohen, C. M. S.; Gomez-Herrero, R.; Heber, B.; Klassen, A.; Leske, R. A.; Mason, G. M.; Mewaldt, R. A.; von Rosenvinge, T. T.

    2014-01-01

    Since the beginning of the Solar Terrestrial Relations Observatory (STEREO) mission at the end of 2006, the two spacecraft have now separated by more than 130? degrees from the Earth. A 360-degree view of the Sun has been possible since February 2011, providing multipoint in situ and remote sensing observations of unprecedented quality. Combining STEREO observations with near-Earth measurements allows the study of solar energetic particle (SEP) events over a wide longitudinal range with minimal radial gradient effects. This contribution provides an overview of recent results obtained by the STEREO/IMPACT team in combination with observations by the ACE and SOHO spacecraft. We focus especially on multi-spacecraft investigations of SEP events. The large longitudinal spread of electron and 3He-rich events as well as unusual anisotropies will be presented and discussed.

  5. Characterization of Miniature Millimeter-Wave Vivaldi Antenna for Local Multipoint Distribution Service

    NASA Technical Reports Server (NTRS)

    Simon, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents first, an efficient measurement technique to characterize the input impedance of a Vivaldi antenna, second, a simple technique to impedance match a Vivaldi antenna to a 50 Ohm feed line and lastly, a desktop arrangement to determine the directional gain of a Vivaldi antenna. The characterization is done using a microwave wafer probe station, a ground-signal microwave probe, impedance standard substrate and an automatic network analyzer. The Vivaldi antenna with a matching transformer has a VSVIR close to unity and a gain of about 10 dB over the frequency band of 27.5 to 28.35 GHz which is allocated for local multipoint distribution service (LMDS).

  6. A multi-point radial photonic Doppler velocimetry (PDV) diagnostic for cylindrical implosion experiments

    NASA Astrophysics Data System (ADS)

    Dalton, Devon; Dolan, Daniel; Lemke, Raymond; McBride, Ryan; Martin, Matthew; Harding, Eric; Walker, Scott

    2013-06-01

    Radial photonic Doppler velocimetry (PDV) has been successfully applied in cylindrical implosion experiments fielded on Sandia's Z accelerator. Magnetically driven cylinders have been diagnosed well beyond 20 km/s, using a ``leapfrog'' configuration to address the bandwidth limitations of currently available detectors and digitizers. Implosion symmetry is the latest question this diagnostic will attempt to answer. An innovative multi-point configuration is being developed to allow six concurrent measurements during each experiment. This presentation describes the implementation of radial PDV in this extreme environment. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. Application of the Multipoint Method to the Kinetics of Accelerator-Driven Systems

    SciTech Connect

    Ravetto, P.; Rostagno, M.M.; Bianchini, G.; Carta, M.; D'Angelo, A.

    2004-09-15

    The mathematical foundations of the multipoint method are illustrated and the method is developed for the neutron kinetics of multiplying systems to treat physical situations in which spatial and spectral effects can play an important role in transient conditions, and hence the classical point-kinetic model can become inadequate. In the present paper the method is specifically developed for source-driven systems, through a proper adaptation of the factorization-projection technique used to derive other classic kinetic models. The results presented for some test cases show the advantages that can be attained with respect to the standard point model, even when treating relevant spatial and spectral transients. It is then shown how the technique can be inserted into a quasi-static framework.

  8. Design of a multi-point microwave interferometer using the electro-optic effect

    NASA Astrophysics Data System (ADS)

    Specht, Paul E.; Cooper, Marcia A.; Jilek, Brook A.

    2017-01-01

    A multi-point microwave interferometer (MPMI) concept is presented for non-invasively monitoring the internal transit of a shock, detonation, or reaction front in energetic media. The concept utilizes an electro-optic (EO) crystal to impart a time-varying phase lag onto a laser with a microwave signal. Polarization optics convert this phase lag into an amplitude modulation. A heterodyne interferometer compares the modulated laser beam to a constant reference. This enables the detection of changes in the modulating microwave frequency generated by the motion of the measurement surface. The design is scalable and makes use of the established construction and analysis methods employed in photonic Doppler velocimetry (PDV). The technical challenges associated with the concept are the frequency stability of the lasers, the amount of light return after EO modulation, and the frequency uncertainty of fast Fourier transform (FFT) methods.

  9. Alternative licensing arrangements and spectrum economics: The case of multipoint distribution service

    NASA Technical Reports Server (NTRS)

    Agnew, C. E.

    1981-01-01

    At present, the Federal Communications Commission assigns radio licenses following a determination of the public interest. Whenever mutually conflicting license applications are filed, the Commission holds a comparative hearing. This assignment mechanism is criticized as cumbersome and unrealiable, and three alternatives are proposed: increasing the available spectrum, and either auctions or lotteries of radio licenses. An analysis is presented of the present system and these alternative arrangments for assigning rights to the frequency spectrum for the Multipoint Distribution Service (MDS). Although MDS is a relatively minor radio service, it serves as a prototype for message distribution services with a large potential for use in business communications. Moreover, the way in which the initial batch of MDS licenses was assigned provides a unique opportunity for empirical work on the economics of the licensing process.

  10. "Multipoint Force Feedback" Leveling of Massively Parallel Tip Arrays in Scanning Probe Lithography.

    PubMed

    Noh, Hanaul; Jung, Goo-Eun; Kim, Sukhyun; Yun, Seong-Hun; Jo, Ahjin; Kahng, Se-Jong; Cho, Nam-Joon; Cho, Sang-Joon

    2015-09-16

    Nanoscale patterning with massively parallel 2D array tips is of significant interest in scanning probe lithography. A challenging task for tip-based large area nanolithography is maintaining parallel tip arrays at the same contact point with a sample substrate in order to pattern a uniform array. Here, polymer pen lithography is demonstrated with a novel leveling method to account for the magnitude and direction of the total applied force of tip arrays by a multipoint force sensing structure integrated into the tip holder. This high-precision approach results in a 0.001° slope of feature edge length variation over 1 cm wide tip arrays. The position sensitive leveling operates in a fully automated manner and is applicable to recently developed scanning probe lithography techniques of various kinds which can enable "desktop nanofabrication."

  11. Optimization of penicillin G acylase multipoint immobilization on to glutaraldehyde-chitosan beads.

    PubMed

    Adriano, Wellington S; Filho, Edilson H C; Silva, James A; Gonçalves, Luciana R B

    2005-06-01

    The objective of this work was to study the immobilization of penicillin G acylase from Escherichia coli on to chitosan-glutaraldehyde beads by multipoint covalent binding. This process was optimized using a 2(3) experimental design. The parameters selected for the present study were the concentrations of glutaraldehyde, phenylacetic acid and sodium borohydride. Three responses were chosen, namely immobilization yield and stabilization factors of enzyme derivatives at high temperature and at alkaline pH. All the runs at the maximum (+1) and minimum (-1) levels were performed at random. Three experiments were performed at the centre point, coded as zero, for experimental-error estimation. With respect to immobilization yield, the main effectors were the concentrations of glutaraldehyde and phenylacetic acid. For stabilization factors at 50 degrees C and at alkaline pH, the main effectors were the concentrations of glutaraldehyde and sodium borohydride and the interaction between them.

  12. Constrained optimization using a multipoint type chaotic Lagrangian method with a coupling structure

    NASA Astrophysics Data System (ADS)

    Okamoto, Takashi; Hirata, Hironori

    2013-03-01

    This article proposes a new constrained optimization method using a multipoint type chaotic Lagrangian method that utilizes chaotic search trajectories generated by Lagrangian gradient dynamics with a coupling structure. In the proposed method, multiple search points autonomously implement global search using the chaotic search trajectory generated by the coupled Lagrangian gradient dynamics. These points are advected to elite points (which are chosen by considering their objective function values and their feasibility) by the coupling in order to explore promising regions intensively. In this way, the proposed method successfully provides diversification and intensification for constrained optimization problems. The effectiveness of the proposed method is confirmed through application to various types of benchmark problem, including the coil spring design problem, the benchmark problems used in the special session on constrained real parameter optimization in CEC2006, and a high-dimensional and multi-peaked constrained optimization problem.

  13. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts

    NASA Astrophysics Data System (ADS)

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  14. Development of an FPGA-based multipoint laser pyroshock measurement system for explosive bolts.

    PubMed

    Abbas, Syed Haider; Jang, Jae-Kyeong; Lee, Jung-Ryul; Kim, Zaeill

    2016-07-01

    Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure. This paper presents a technology to measure a pyroshock wave at multiple points using laser Doppler vibrometers (LDVs). These LDVs detect the pyroshock wave generated due to an explosive-based pyrotechnical event. Field programmable gate array (FPGA) based data acquisition is used in the study to acquire pyroshock signals simultaneously from multiple channels. This paper describes the complete system design for multipoint pyroshock measurement. The firmware architecture for the implementation of multichannel data acquisition on an FPGA-based development board is also discussed. An experiment using explosive bolts was configured to test the reliability of the system. Pyroshock was generated using explosive excitation on a 22-mm-thick steel plate. Three LDVs were deployed to capture the pyroshock wave at different points. The pyroshocks captured were displayed as acceleration plots. The results showed that our system effectively captured the pyroshock wave with a peak-to-peak magnitude of 303 741 g. The contribution of this paper is a specialized architecture of firmware design programmed in FPGA for data acquisition of large amount of multichannel pyroshock data. The advantages of the developed system are the near-field, multipoint, non-contact, and remote measurement of a pyroshock wave, which is dangerous and expensive to produce in aerospace pyrotechnic tests.

  15. 76 FR 70979 - Notice of Availability of the Draft Environmental Impact Statement for the Proposed Point Thomson...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ... infrastructure and produce liquid hydrocarbon resources near Point Thomson, Alaska. The proposed project includes... application on November 1, 2011. The Applicant's purpose is to produce liquid hydrocarbons and delineate and evaluate hydrocarbon resources in the Point Thomson area. Two natural gas production wells have...

  16. An Account of ... William Cullen: John Thomson and the Making of a Medical Biography.

    PubMed

    Shuttleton, David E

    2014-01-01

    John Thomson's An Account of the Life, Lectures and Writings of William Cullen (1832; 1859) remains a primary source for the career of the most influential academic physician in eighteenth-century Scotland and is also a significant work of medical history. But this multi-authored text, begun around 1810 by the academic surgeon, John Thomson, but only completed in 1859 by Dr David Craigie, has its own complex history. This chapter addresses what this history can reveal about the development of medical biography as a literary genre. It argues that the Account is a hybrid work shaped by a complex array of practical, domestic, intellectual, and professional pressures, as Thomson, in seeking to bolster his own career, was caught between the demands of Cullen's children for a traditional "Life" and his own more theoretical and socio-cultural interests.

  17. Controlled generation of comb-like electron beams in plasma channels for polychromatic inverse Thomson γ-ray sources

    NASA Astrophysics Data System (ADS)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Lehe, R.; Lifschitz, A. F.; Shadwick, B. A.

    2016-03-01

    Propagating a relativistically intense, negatively chirped laser pulse (the bandwidth  >150 nm) in a plasma channel makes it possible to generate background-free, comb-like electron beams—sequences of synchronized bunches with a low phase-space volume and controlled energy spacing. The tail of the pulse, confined in the accelerator cavity (an electron density ‘bubble’), experiences periodic focusing, while the head, which is the most intense portion of the pulse, steadily self-guides. Oscillations of the cavity size cause periodic injection of electrons from the ambient plasma, creating an electron energy comb with the number of components, their mean energy, and energy spacing dependent on the channel radius and pulse length. These customizable electron beams enable the design of a tunable, all-optical source of pulsed, polychromatic γ-rays using the mechanism of inverse Thomson scattering, with up to  ˜10-5 conversion efficiency from the drive pulse in the electron accelerator to the γ-ray beam. Such a source may radiate  ˜107 quasi-monochromatic photons per shot into a microsteradian-scale cone. The photon energy is distributed among several distinct bands, each having sub-30% energy spread, with a highest energy of 12.5 MeV.

  18. Universal Scattering Property of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Hall, C. R.; Bruhweiler, F. C.; Madejski, G. M.

    1996-12-01

    The dusty torus model of Seyfert galaxies--the so-called Unified Model--(Antonucci & Miller 1985; Antonucci 1993) states that both type 1 and type 2 objects are intrinsically the same and share a similar overall geometry. Depending upon the observer's line of sight to the central engine, the broad lines which define the Seyfert type may be visible (Sy 1) or obscured by the torus (Sy 2), while the narrow lines are equally visible in both classes. In addition the polar regions of the torus contain an electron scattering atmosphere, extending beyond the polar openings. Via Thomson scattering of central engine photons, the broad line feature in Sy 2s can only be detected in polarized light. From an empirical analysis comparing the narrow Balmer H-beta observed in a sample of objects from both classes against the broad Balmer H-beta observed directly in Seyfert 1s, and observed in polarized light in Seyfert 2s, we find a general scattering law: the ratio of the intrinsic luminosity to the polarized luminosity in the line is approximately 300. This has strong implications on the geometry and physical properties of the scattering medium. References: Antonucci, R.R.J. 1993,ARA&A, 31, 473 Antonucci, R.R.J.,& Miller,J.S. 1985,ApJ, 297, 621

  19. Scattering intensities for a white beam (120 kV) presenting a semi-empirical model to preview scattered beams

    NASA Astrophysics Data System (ADS)

    Gonçalves, O. D.; Boldt, S.; Kasch, K. U.

    2016-09-01

    This work aims at measuring the scattering cross sections for white beams and the verification of a semi-empirical model predicting scattered energy spectra of an X-ray beam produced by an industrial X-ray tube (Pantack Sievert, 120 kV, tungsten target) incident on a water sample. Both, theoretical and semi-empirical results presented are based on the form factor approach with results well corresponding to performed measurements. The elastic (Rayleigh) scattering cross sections are based on Thomson scattering with a form factor correction as published by Morin (1982). The inelastic (Compton) contribution is based on the Klein Nishina equation (Klein and Nishina, 1929) multiplied by the incoherent scattering factors calculated by Hubbel et al. (1975). Two major results are presented: first, the experimental integrated in energy cross sections corresponds with theoretical cross sections obtained at the mean energy of the measured scattered spectra at a given angle. Secondly, the measured scattered spectra at a given angle correspond to those obtained utilizing the semi-empirical model as proposed here. A good correspondence of experimental results and model predictions can be shown. The latter, therefore, proves to be a useful method to calculate the scattering contributions in a number of applications as for example cone beam tomography.

  20. Multipoint near-infrared spectrometry for real-time monitoring of protein conformational stability in powdered infant formula.

    PubMed

    Pabari, Ritesh M; Togashi, Denisio; Cama-Moncunill, Raquel; El Arnaout, Toufic; Rifai, Hicham; Cruise, Paul; Cullen, Patrick J; Sullivan, Carl

    2015-01-01

    Powdered infant formula (PIF) can be the sole source of nutrition for babies and infants. Monitoring conformational changes in protein during manufacture of PIF is critical in order to maintain its nutritional value. This study presents the development of a calibration model for monitoring conformational changes in PIF protein by applying a novel multipoint near-infrared (NIR) spectrometry. NIR spectra were collected for PIF and PIF proteins, casein and whey protein isolate, before and after heat treatment. Results show that principal component analysis showed discrimination between native protein at room temperature and protein conformational changes caused at elevated temperature. Partial least squares regression analysis showed good calibration models with correlation coefficients ranging between 87% and 99% for the prediction of protein quality. This novel multipoint NIR spectrometry could serve as a simple in-line tool to rapidly monitor protein quality during processing stages, contributing to product nutritional value.