WorldWideScience

Sample records for beam emission spectroscopy

  1. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  2. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    International Nuclear Information System (INIS)

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region

  3. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  4. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  5. Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak.

    Science.gov (United States)

    Li, Y Y; Fu, J; Lyu, B; Du, X W; Li, C Y; Zhang, Y; Yin, X H; Yu, Y; Wang, Q P; von Hellermann, M; Shi, Y J; Ye, M Y; Wan, B N

    2014-11-01

    Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented. PMID:25430335

  6. Bayesian modelling of the emission spectrum of the Joint European Torus Lithium Beam Emission Spectroscopy system.

    Science.gov (United States)

    Kwak, Sehyun; Svensson, J; Brix, M; Ghim, Y-C

    2016-02-01

    A Bayesian model of the emission spectrum of the JET lithium beam has been developed to infer the intensity of the Li I (2p-2s) line radiation and associated uncertainties. The detected spectrum for each channel of the lithium beam emission spectroscopy system is here modelled by a single Li line modified by an instrumental function, Bremsstrahlung background, instrumental offset, and interference filter curve. Both the instrumental function and the interference filter curve are modelled with non-parametric Gaussian processes. All free parameters of the model, the intensities of the Li line, Bremsstrahlung background, and instrumental offset, are inferred using Bayesian probability theory with a Gaussian likelihood for photon statistics and electronic background noise. The prior distributions of the free parameters are chosen as Gaussians. Given these assumptions, the intensity of the Li line and corresponding uncertainties are analytically available using a Bayesian linear inversion technique. The proposed approach makes it possible to extract the intensity of Li line without doing a separate background subtraction through modulation of the Li beam. PMID:26931843

  7. Development of fast helium beam emission spectroscopy for plasma density and temperature diagnostics

    International Nuclear Information System (INIS)

    For developing a novel electron density and -temperature diagnostics based on fast He beam emission spectroscopy, experiments have been performed at the ASDEX Upgrade tokamak (AUG) in Garching and the JET tokamak in Culham. The measured He I emission profiles were compared with model calculations which are based on a collisional-radiative model developed by the ADAS group. For exploratory measurements at AUG one of the heating beam sources has been operated with pure helium. The beam emission profiles show satisfactory agreement with the profiles modelled using density and temperature profiles from other diagnostics. At JET and recently at AUG a small amount of helium was added to one standard deuterium ion source in order to produce a 'doped' helium/deuterium beam. The respective measurements were performed using groups of identical pulses. In total, 11 different He I lines were investigated at JET with respect to their dependence on plasma density and -temperature. Seven lines were found to have sufficient intensity but the beam emission profile suffers from limited bandwidth of the spectrometer used. Good beam emission profiles could be obtained from recent AUG measurements showing a scatter of 9%. (author)

  8. Overview of the beam emission spectroscopy diagnostic system on the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    A beam emission spectroscopy (BES) system has been installed on the National Spherical Torus Experiment (NSTX) to study ion gyroscale fluctuations. The BES system measures Dα emission from a deuterium neutral heating beam. The system includes two optical views centered at r/a≅0.45 and 0.85 and aligned to magnetic field pitch angles at the neutral beam. f/1.5 collection optics produce 2-3 cm spot sizes at the neutral beam. The initial channel layout includes radial arrays, poloidal arrays, and two-dimensional grids. Radial arrays provide coverage from r/a≅0.1 to beyond the last-closed flux surface. Photodetectors and digital filters provide high-sensitivity, low-noise measurements at frequencies of up to 1 MHz. The BES system will be a valuable tool for investigating ion gyroscale turbulence and Alfven/energetic particle modes on NSTX.

  9. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research.

    Science.gov (United States)

    Lampert, M; Anda, G; Czopf, A; Erdei, G; Guszejnov, D; Kovácsik, Á; Pokol, G I; Réfy, D; Nam, Y U; Zoletnik, S

    2015-07-01

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera's measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties. PMID:26233377

  10. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    International Nuclear Information System (INIS)

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties

  11. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, M. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); BME NTI, Budapest (Hungary); Anda, G.; Réfy, D.; Zoletnik, S. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); Czopf, A.; Erdei, G. [Department of Atomic Physics, BME IOP, Budapest (Hungary); Guszejnov, D.; Kovácsik, Á.; Pokol, G. I. [BME NTI, Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  12. Beam emission spectroscopy for density turbulence measurements on the MAST spherical tokamak

    International Nuclear Information System (INIS)

    Beam emission spectroscopy (BES) of the energetic deuterium (D0) heating beams can provide a means of characterizing the density turbulence in tokamak plasmas. First such measurements have been performed on the MAST spherical tokamak using a trial BES system, which shares the collection optics of the charge-exchange recombination spectroscopy system. This system, with eight spatial channels covering the outer part of the plasma cross section, uses avalanche photodiode detectors with custom preamplifiers to provide measurements at 1 MHz bandwidth with a spatial resolution of 4 cm. Simulations of the measurement, including the beam absorption and excitation, line-of-sight integration of the emission spectrum, and the characteristics of the detection system have been benchmarked against the measured absolute intensity of the Doppler shifted Dα fluorescence from the 50 keV beam. This gives confidence in predictions of the performance of a two-dimensional imaging BES system planned for MAST. Correlation techniques have also provided information on the characteristics of the density turbulence at the periphery of L-mode plasmas as well as density perturbations due to coherent magnetohydrodynamic activity at the edge of H-mode plasmas. Precursor oscillations of the density in the pedestal region to edge-localized modes occurring during H-mode plasmas with a single-null diverted magnetic configuration are also observable in the raw signals from the trial BES system.

  13. Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy

    International Nuclear Information System (INIS)

    Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF6 discharge and endpoint detection capabilities in dark plasma process conditions. In SF6 discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF4 gas phase species.

  14. Development of lithium beam emission spectroscopy as an edge fluctuation diagnostic for DIII-D

    International Nuclear Information System (INIS)

    As part of the DIII-D diagnostic complement designed to address L-H transition physics issues, we have developed and commissioned a diagnostic neutral lithium beam and multichannel fluorescence detection system to investigate the edge plasma density and its associated fluctuations. The use of lithium offers several advantages for tokamak edge beam emission spectroscopy (BES) studies, including large excitation cross sections which are relatively insensitive to temperature variation, the availability of the 670.8 nm resonance line well separated from most plasma line emission, and the suitability of modest beam energies and currents to probe even dense H-mode plasmas. These features permit measurements of collisionally induced fluctuations to be obtained with good spatial (<1 cm) and temporal (<10 μs) resolution. The improvements over previous lithium beam diagnostics which were required to successfully make these measurements in a large, remotely controlled machine environment will be discussed, a long with the present state of the diagnostic system and our plans for future improvements of this technique

  15. Three-dimensional modeling of beam emission spectroscopy measurements in fusion plasmas

    CERN Document Server

    Guszejnov, D; Pusztai, I; Refy, D; Zoletnik, S; Lampert, M; Nam, Y U; 10.1063/1.4764564

    2013-01-01

    One of the main diagnostic tools for measuring electron density profiles and the characteristics of long wavelength turbulent wave structures in fusion plasmas is Beam Emission Spectroscopy (BES). The increasing number of BES systems necessitated an accurate and comprehensive simulation of BES diagnostics, which in turn motivated the development of the RENATE simulation code that is the topic of this paper. RENATE is a modular, fully three-dimensional code incorporating all key features of BES systems from the atomic physics to the observation, including an advanced modeling of the optics. Thus RENATE can be used both in the interpretation of measured signals and the development of new BES systems. The most important components of the code have been successfully benchmarked against other simulation codes. The primary results have been validated against experimental data from the KSTAR tokamak.

  16. Status of electron temperature and density measurement with beam emission spectroscopy on thermal helium at TEXTOR

    International Nuclear Information System (INIS)

    Beam emission spectroscopy on thermal helium is used at the TEXTOR tokamak as a reliable method to obtain radial profiles of electron temperature Te(r, t) and electron density ne(r, t). In this paper the experimental realization of this method at TEXTOR and the status of the atomic physics employed as well as the major factors for the measurement's accuracy are evaluated. On the experimental side, the hardware specifications are described and the impact of the beam atoms on the local plasma parameters is shown to be negligible. On the modeling side the collisional-radiative model (CRM) applied to infer ne and Te from the measured He line intensities is evaluated. The role of proton and deuteron collisions and of charge exchange processes is studied with a new CRM and the impact of these so far neglected processes appears to be of minor importance. Direct comparison to Thomson scattering and fast triple probe data showed that for high densities ne > 3.5 x 1019 m-3 the Te values deduced with the established CRM are too low. However, the new atomic data set implemented in the new CRM leads in general to higher Te values. This allows us to specify the range of reliable application of BES on thermal helium to a range of 2.0 x 1018 e 19 m-3 and 10 eV e < 250 eV which can be extended by routine application of the new CRM.

  17. Active Beam Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.

    2008-03-01

    Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters

  18. Note: Spectrometer with multichannel photon-counting detector for beam emission spectroscopy in magnetic fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Lizunov, A. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Khilchenko, A. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630073 Novosibirsk (Russian Federation); Khilchenko, V.; Kvashnin, A.; Zubarev, P. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)

    2015-12-15

    A spectrometer based on a linear array photomultiplier tube (PMT) has been developed and calibrated. A 0.635 m focal length Czerny-Turner monochromator combined with a coupling optics provides an image of a narrow 0.5 nm spectral range with a resolution of 0.015 nm/channel on a 32-anode PMT. The system aims at spectroscopy of D{sub α} or H{sub α} lines emitted by a diagnostic atomic beam in a plasma (primarily a motional Stark effect diagnostics). To record a low photon flux of ∼10{sup 6} s{sup −1} per channel with the time resolution of 100 μs, a pulse counting approach has been used. Wideband amplifiers scale single-electron pulses and transmit them to a digital data processing core hardwired in a programmable logic matrix. Calibrations have shown that the aberration-limited instrument function fits to a single detector channel of 1 mm width. Pilot results of passive measurements of D{sub α} light emission from the plasma confined in a magnetic trap are presented.

  19. Note: Spectrometer with multichannel photon-counting detector for beam emission spectroscopy in magnetic fusion devices

    Science.gov (United States)

    Lizunov, A.; Khilchenko, A.; Khilchenko, V.; Kvashnin, A.; Zubarev, P.

    2015-12-01

    A spectrometer based on a linear array photomultiplier tube (PMT) has been developed and calibrated. A 0.635 m focal length Czerny-Turner monochromator combined with a coupling optics provides an image of a narrow 0.5 nm spectral range with a resolution of 0.015 nm/channel on a 32-anode PMT. The system aims at spectroscopy of Dα or Hα lines emitted by a diagnostic atomic beam in a plasma (primarily a motional Stark effect diagnostics). To record a low photon flux of ˜106 s-1 per channel with the time resolution of 100 μs, a pulse counting approach has been used. Wideband amplifiers scale single-electron pulses and transmit them to a digital data processing core hardwired in a programmable logic matrix. Calibrations have shown that the aberration-limited instrument function fits to a single detector channel of 1 mm width. Pilot results of passive measurements of Dα light emission from the plasma confined in a magnetic trap are presented.

  20. Note: Spectrometer with multichannel photon-counting detector for beam emission spectroscopy in magnetic fusion devices

    International Nuclear Information System (INIS)

    A spectrometer based on a linear array photomultiplier tube (PMT) has been developed and calibrated. A 0.635 m focal length Czerny-Turner monochromator combined with a coupling optics provides an image of a narrow 0.5 nm spectral range with a resolution of 0.015 nm/channel on a 32-anode PMT. The system aims at spectroscopy of Dα or Hα lines emitted by a diagnostic atomic beam in a plasma (primarily a motional Stark effect diagnostics). To record a low photon flux of ∼106 s−1 per channel with the time resolution of 100 μs, a pulse counting approach has been used. Wideband amplifiers scale single-electron pulses and transmit them to a digital data processing core hardwired in a programmable logic matrix. Calibrations have shown that the aberration-limited instrument function fits to a single detector channel of 1 mm width. Pilot results of passive measurements of Dα light emission from the plasma confined in a magnetic trap are presented

  1. Neutral beam emission spectroscopy diagnostic for measurement of density fluctuations on the TFTR tokamak

    International Nuclear Information System (INIS)

    A multi-channel diagnostic for measuring low amplitude, long wavelength (kperpendicularρi α fluorescence of a neutral heating beam due to collisional excitation from the plasma and impurity ions. Both radial and poloidal correlation lengths as short as 2--3 cm can be determined, with the spatial resolution limited primarily by the width and geometry of the three neutral beam sources. Optical fibers transmit the light from a 20-cm diameter vacuum window, re-entrant mirror, and lens assembly to sixteen interference filter/photomultiplier combinations located outside the radiation area. Initially, the fibers comprise a fixed 55-channel radial array and readily movable 10-channel vertical arrays which can be positioned at 27 radial locations. The filters are designed to accept the Doppler-shifted Hα emission from primary energy component of the neutral beam, and reject background lines and unshifted edge Hα. The measurable fluctuation amplitude (at sign S/N = 1) is limited to 0.5% over a 100 kHz bandwidth by the photon noise associated with the DC level of the beam emission. The contribution of impurities to the total beam fluorescence will be determined directly by measuring impurity density fluctuations using charge exchange recombination emission from the n = 8 - 7 CVI line at 5292 angstrom. 6 refs., 2 figs., 2 tabs

  2. Neutral beam emission spectroscopy diagnostic for measurement of density fluctuations on the TFTR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Paul, S.F. (Princeton Univ., NJ (USA). Plasma Physics Lab.); Fonck, R.J. (Wisconsin Univ., Madison, WI (USA). Dept. of Nuclear Engineering)

    1990-06-01

    A multi-channel diagnostic for measuring low amplitude, long wavelength (k{sub {perpendicular}{rho}i} < 0.5) density fluctuations along the outer half of the plasma has been installed on TFTR. It is based on observing fluctuations in the H{sub {alpha}} fluorescence of a neutral heating beam due to collisional excitation from the plasma and impurity ions. Both radial and poloidal correlation lengths as short as 2--3 cm can be determined, with the spatial resolution limited primarily by the width and geometry of the three neutral beam sources. Optical fibers transmit the light from a 20-cm diameter vacuum window, re-entrant mirror, and lens assembly to sixteen interference filter/photomultiplier combinations located outside the radiation area. Initially, the fibers comprise a fixed 55-channel radial array and readily movable 10-channel vertical arrays which can be positioned at 27 radial locations. The filters are designed to accept the Doppler-shifted H{sub {alpha}} emission from primary energy component of the neutral beam, and reject background lines and unshifted edge H{sub {alpha}}. The measurable fluctuation amplitude ( S/N = 1) is limited to 0.5% over a 100 kHz bandwidth by the photon noise associated with the DC level of the beam emission. The contribution of impurities to the total beam fluorescence will be determined directly by measuring impurity density fluctuations using charge exchange recombination emission from the n = 8 {minus} 7 CVI line at 5292 {angstrom}. 6 refs., 2 figs., 2 tabs.

  3. Grating spectrometer system for beam emission spectroscopy diagnostics using high-energy negative-ion-based neutral beam injection on LHD

    International Nuclear Information System (INIS)

    A beam emission spectroscopy (BES) system was developed for density gradient and fluctuation diagnostics in the Large Helical Device (LHD). In order to cover the large Doppler shift of the Hα beam emission because of the high-energy negative-ion-based neutral beam atom (acceleration voltage Vacc=90-170 kV) and the large motional Stark splitting due to the large vxB field (magnetic field B=3.0 T), a grating spectrometer was used instead of a conventional interference filter system. The reciprocal linear dispersion is about 2 nm/mm, which is sufficient to cover the motional Stark effect spectra using an optical fiber with a diameter of 1 mm.

  4. Edge electron density profiles and fluctuations measured by two-dimensional beam emission spectroscopy in the KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Y. U., E-mail: yunam@nfri.re.kr; Wi, H. M. [National Fusion Research Institute, Daejeon (Korea, Republic of); Zoletnik, S.; Lampert, M. [Wigner RCP Institute for Particle and Nuclear Physics, Budapest (Hungary); Kovácsik, Ákos [Institute of Nuclear Techniques, Budapest Technical University, Budapest (Hungary)

    2014-11-15

    Beam emission spectroscopy (BES) system in Korea Superconducting Tokamak Advanced Research (KSTAR) has recently been upgraded. The background intensity was reduced from 30% to 2% by suppressing the stray lights. This allows acquisition of the relative electron density profiles on the plasma edge without background subtraction from the beam power modulation signals. The KSTAR BES system has its spatial resolution of 1 cm, the temporal resolution of 2 MHz, and a total 32 channel (8 radial × 4 poloidal) avalanche photo diode array. Most measurements were done on the plasma edge, r/a ∼ 0.9, with 8 cm radial measurement width that covers the pedestal range. High speed density profile measurements reveal temporal behaviors of fast transient events, such as the precursors of edge localized modes and the transitions between confinement modes. Low background level also allows analysis of the edge density fluctuation patterns with reduced background fluctuations. Propagation of the density structures can be investigated by comparing the phase delays between the spatially distributed channels.

  5. Comparison of beam emission spectroscopy and gas puff imaging edge fluctuation measurements in National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    In this study, the close physical proximity of the Gas Puff Imaging (GPI) and Beam Emission Spectroscopy (BES) diagnostics on the National Spherical torus Experiment (NSTX) is leveraged to directly compare fluctuation measurements, and to study the local effects of the GPI neutral deuterium puff during H-mode plasmas without large Edge Localized Modes. The GPI and BES views on NSTX provide partially overlapping coverage of the edge and scrape-off layer (SOL) regions above the outboard midplane. The separation in the toroidal direction is 16°, and field lines passing through diagnostic views are separated by ∼20 cm in the direction perpendicular to the magnetic field. Strong cross-correlation is observed, and strong cross-coherence is seen for frequencies between 5 and 15 kHz. Also, probability distribution functions of fluctuations measured ∼3 cm inside the separatrix exhibit only minor deviations from a normal distribution for both diagnostics, and good agreement between correlation length estimates, decorrelation times, and structure velocities is found at the ±40% level. While the two instruments agree closely in many respects, some discrepancies are observed. Most notably, GPI normalized fluctuation levels exceed BES fluctuations by a factor of ∼9. BES mean intensity is found to be sensitive to the GPI neutral gas puff, and BES normalized fluctuation levels for frequencies between 1 and 10 kHz are observed to increase during the GPI puff

  6. Comparison of beam emission spectroscopy and gas puff imaging edge fluctuation measurements in National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sechrest, Y.; Munsat, T. [Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Smith, D. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Stotler, D. P.; Zweben, S. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2015-05-15

    In this study, the close physical proximity of the Gas Puff Imaging (GPI) and Beam Emission Spectroscopy (BES) diagnostics on the National Spherical torus Experiment (NSTX) is leveraged to directly compare fluctuation measurements, and to study the local effects of the GPI neutral deuterium puff during H-mode plasmas without large Edge Localized Modes. The GPI and BES views on NSTX provide partially overlapping coverage of the edge and scrape-off layer (SOL) regions above the outboard midplane. The separation in the toroidal direction is 16°, and field lines passing through diagnostic views are separated by ∼20 cm in the direction perpendicular to the magnetic field. Strong cross-correlation is observed, and strong cross-coherence is seen for frequencies between 5 and 15 kHz. Also, probability distribution functions of fluctuations measured ∼3 cm inside the separatrix exhibit only minor deviations from a normal distribution for both diagnostics, and good agreement between correlation length estimates, decorrelation times, and structure velocities is found at the ±40% level. While the two instruments agree closely in many respects, some discrepancies are observed. Most notably, GPI normalized fluctuation levels exceed BES fluctuations by a factor of ∼9. BES mean intensity is found to be sensitive to the GPI neutral gas puff, and BES normalized fluctuation levels for frequencies between 1 and 10 kHz are observed to increase during the GPI puff.

  7. Photoelectron photoion molecular beam spectroscopy

    International Nuclear Information System (INIS)

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed

  8. Ballistic-electron-emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kaenel, H. von; Klemenc, M.; Meyer, T. [Eidgenoessische Technische Hochschule, Zurich (Switzerland). Lab. fuer Festkoerperphysik

    2001-04-01

    Ballistic electron-emission spectroscopy (BEES) and microscopy (BEEM) have been carried out on epitaxial metal/semiconductor interfaces and on epitaxial nanostructures in UHV and at low temperatures. We describe how the band structure of the metal may lead to pronounced focusing of the hot carrier beam injected by the scanning tunneling microscope (STM) tip, thereby greatly enhancing the spatial resolution, such that spectroscopy at buried point defects becomes possible. The strain fields of Ge quantum dots buried underneath an epitaxial silicide film on a Si(100) substrate are found to induce a characteristic clustering of linear defects at the metal/semiconductor interface. The Schottky barrier height lowering associated with these defects allows for an easy identification of buried dots, despite the many mechanisms leading to contrast in BEEM images. (orig.)

  9. Measurement and physical interpretation of the mean motion of turbulent density patterns detected by the beam emission spectroscopy system on the mega amp spherical tokamak

    International Nuclear Information System (INIS)

    The mean motion of turbulent patterns detected by a two-dimensional beam emission spectroscopy (BES) diagnostic on the mega amp spherical tokamak (MAST) is determined using a cross-correlation time delay method. Statistical reliability of the method is studied by means of synthetic data analysis. The experimental measurements on MAST indicate that the apparent mean poloidal motion of the turbulent density patterns in the lab frame arises because the longest correlation direction of the patterns (parallel to the local background magnetic fields) is not parallel to the direction of the fastest mean plasma flows (usually toroidal when strong neutral-beam injection is present). This effect is particularly pronounced in a spherical tokamak because of the relatively large mean rotation and large magnetic pitch angle. The experimental measurements are consistent with the mean motion of plasma being toroidal. The sum of all other contributions (mean poloidal plasma flow, phase velocity of the density patterns in the plasma frame, non-linear effects, etc) to the apparent mean poloidal velocity of the density patterns is found to be negligible. These results hold in all investigated L-mode, H-mode and internal transport barrier discharges. The one exception is a high-poloidal-beta (the ratio of the plasma pressure to the poloidal magnetic field energy density) discharge, where a large magnetic island exists. In this case BES detects very little motion. This effect is currently theoretically unexplained. (paper)

  10. Positronium emission spectroscopy

    International Nuclear Information System (INIS)

    Measurements of the intensity, velocity, and angular distribution of positronium emitted from solid samples of metals and insulators have been performed using the intense, pulsed positron beam from the 100 MeV electron linac. From these data it is possible to determine properties of both the surface interactions and volume potentials of the materials studied. Examples of these effects will be given using measurements of positronium time of flight performed with the Livermore intense positron beam. The time of flight data have been augmented by positron lifetime and angular correlation measurements performed with the beam. Measurements resulting in workfunctions, deformation potentials and surface interaction effects will be reported for both metals and insulators. 18 refs., 2 figs

  11. Atomic emission spectroscopy in high electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.E.; Filuk, A.B.; Carlson, A.L. [and others

    1995-12-31

    Pulsed-power driven ion diodes generating quasi-static, {approximately}10 MV/cm, 1-cm scale-length electric fields are used to accelerate lithium ion beams for inertial confinement fusion applications. Atomic emission spectroscopy measurements contribute to understanding the acceleration gap physics, in particular by combining time- and space-resolved measurements of the electric field with the Poisson equation to determine the charged particle distributions. This unique high-field configuration also offers the possibility to advance basic atomic physics, for example by testing calculations of the Stark-shifted emission pattern, by measuring field ionization rates for tightly-bound low-principal-quantum-number levels, and by measuring transition-probability quenching.

  12. Atomic emission spectroscopy in high electric fields

    International Nuclear Information System (INIS)

    Pulsed-power driven ion diodes generating quasi-static, ∼10 MV/cm, 1-cm scale-length electric fields are used to accelerate lithium ion beams for inertial confinement fusion applications. Atomic emission spectroscopy measurements contribute to understanding the acceleration gap physics, in particular by combining time- and space-resolved measurements of the electric field with the Poisson equation to determine the charged particle distributions. This unique high-field configuration also offers the possibility to advance basic atomic physics, for example by testing calculations of the Stark-shifted emission pattern, by measuring field ionization rates for tightly-bound low-principal-quantum-number levels, and by measuring transition-probability quenching

  13. Towards in-Beam Spectroscopy of the Heaviest Elements

    International Nuclear Information System (INIS)

    New developments in nuclear spectroscopy of prompt emission at the target and decay emission at the focal plane of recoil separators are described here. In-beam γ-ray measurements of even-even nuclei in the rotational superheavy region, 252;254No, have been carried out. These measurements have revealed the properties of the ground state rotational bands. Attempts to measure the properties of odd mass nuclei await the further development of conversion electron spectroscopy , and early results from the SACRED spectrometer used in conjunction with the recoil separator RITU are given here. The future development of sensitive focal plane instruments, to identify decay processes following the radioactive decay of the parent nucleus is also described. (author)

  14. EXAFS-spectroscopy on synchrotron radiation beam

    CERN Document Server

    Aksenov, V L; Kuzmin, A Y; Purans, Y

    2001-01-01

    In the review the basis theoretical principles of EXAFS spectroscopy are given, as one of principal directions of an absorption spectroscopy permitting with a high accuracy to gain parameters of the short-range order in multicomponent amorphous and quasi-crystal mediums. The methods of the analysis of EXAFS spectra with allowance of effects of multiply scattering are featured. The exposition of the experimental set-ups, which realize the method of EXAFS spectroscopy on beams of SR, requirement of the monochromatization of radiation beams are given. For investigation of phase transition and external effects the energy-dispersive EXAFS spectrometer is creating at the National center of SR Kurchatov Institute which can measure the EXAFS spectrum with a time resolution 3-5 ms. The experimental results on investigation (by the EXAFS spectroscopy method) of oxides of tungsten and molybdenum are given, which have unique property: the variable valence of an ion of metal is depending on external action. The most inter...

  15. Laser spectroscopy on the heavy ion beams

    International Nuclear Information System (INIS)

    In the presented report the perspectives of the study of the electric charge and current space distributions in the nuclei by laser spectroscopy methods on the beams of the fast multiple charged ions are discussed. The calculations of both the level energies and widths in the H-like and He-like ions and of the isotopic shifts and hyperfine splitting in the optical spectra of these ions are performed. The project of the experimental set-up for these measurements is considered. (author)

  16. Accelerated ion beams for in-beam e-gamma spectroscopy

    NARCIS (Netherlands)

    Dionisio, JS; Vieu, C; Schuck, C; Meunier, R; Ledu, D; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Varley, BJ; Durell, JL; Dagnall, PG; Dorning, SJ; Jones, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Folger, H; Vanhorenbeeck, J; Urban, W

    1998-01-01

    A few accelerated ion beam requirements for in-beam e-gamma spectroscopy are briefly reviewed as well as several features of the MP Tandem accelerator of IPN-Orsay and the accelerated ion-beam transport devices leading to the experimental area of in-beam e-gamma spectroscopy. In particular, the main

  17. Hertzian spectroscopy application to excited states in accelerated ion beams

    International Nuclear Information System (INIS)

    It is shown that accelerated ion beams enables the application of optical hertzian spectrometry methods to be extended to research on the excited states of free ionic systems. The photon beat method has proved especially simple to apply in beam foil geometry because of the unidirectional beam velocity while the beam gas device is suitable for experiments of the energy level crossing type. Only the resonance technique involving direct application of high-frequency magnetic fields poses serious problems because of the high HF powers necessary. So far structure intervals have been measured in ions carrying up to three charges (seven in the special case of Lamb shift measurements) with a precision of a few percent. The interest of these structure studies in free ions is emphasized particularly. The study of hydrogen-like or helium-like ions of high Z allows the fundamental calculations of quantum electrodynamics to be checked with regard to the Lamb shift or the spontaneous emission theory. In more complex electronic systems, optical spectroscopy of accelerated ion beams gives wavelengths with a resolution reaching 10-5, lifetimes with an accuracy better than 10% when the cascade effects are properly studied, and Lande factors with a precision of several % under present technical conditions. The photon beat method concerns hyperfine nuclear effects in light atoms of Z<=20. Another line of research study the hyperfine structure of a given configuration in an isoelectronic sequence

  18. Gamma spectroscopy: from steady beams to radioactive beams

    International Nuclear Information System (INIS)

    The author gives an overview of his research works in the field of gamma spectroscopy. First, he recalls some results of experiments performed for the study of peculiar structures associated with different modes of nucleus rotation, and notably in the case of collective rotation of deformed and even super-deformed nuclei. Then, he details tools and methods used to experimentally determine the level scheme. The main characteristics of steady and radioactive beams are briefly presented, and their complementarities and differences are highlighted. Specific spectrometers and sensors are described. In a last chapter, the author discusses several research projects he is involved in, and more particularly the 'gamma tracking' which is the fundamental principle for gamma multi-sensors of the next generations

  19. Electron-beam-sustained discharge revisited - light emission from combined electron beam and microwave excited argon at atmospheric pressure

    CERN Document Server

    Dandl, T; Neumeier, A; Wieser, J; Ulrich, A

    2015-01-01

    A novel kind of electron beam sustained discharge is presented in which a 12keV electron beam is combined with a 2.45GHz microwave power to excite argon gas at atmospheric pressure in a continuous mode of operation. Optical emission spectroscopy is performed over a wide wavelength range from the vacuum ultraviolet (VUV) to the near infrared (NIR). Several effects which modify the emission spectra compared to sole electron beam excitation are observed and interpreted by the changing plasma parameters such as electron density, electron temperature and gas temperature.

  20. Photon emission spectroscopy of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, B.

    1995-10-01

    Emission cross sections for the 1snp{sup 1}P{sub 1}-levels have been measured by photon emission spectroscopy for the collision systems He{sup +} + He at 10 keV and He{sup 2+} + He at 10-35 keV. Photon spectra of Krypton (Kr VIII) and Xenon (Xe V - IX) have also been obtained using 10q keV beams of Kr{sup q+} (q=7-9) and Xe{sup q+} (q=5-9) colliding with Helium and Argon. The Lifetimes of 3p{sup 2}P-levels in Na-like Nb are reported together with lifetime for the 3s3p{sup 3}P{sub 1}-level in Mg-like Ni, Kr, Y, Zr and Nb where this level has an intercombination transition to the ground state. 45 refs, 20 figs.

  1. Photon emission spectroscopy of ion-atom collisions

    International Nuclear Information System (INIS)

    Emission cross sections for the 1snp1P1-levels have been measured by photon emission spectroscopy for the collision systems He+ + He at 10 keV and He2+ + He at 10-35 keV. Photon spectra of Krypton (Kr VIII) and Xenon (Xe V - IX) have also been obtained using 10q keV beams of Krq+ (q=7-9) and Xeq+ (q=5-9) colliding with Helium and Argon. The Lifetimes of 3p2P-levels in Na-like Nb are reported together with lifetime for the 3s3p3P1-level in Mg-like Ni, Kr, Y, Zr and Nb where this level has an intercombination transition to the ground state. 45 refs, 20 figs

  2. Neutron emission spectroscopy for magnetic confinement experiments

    International Nuclear Information System (INIS)

    Neutron diagnostics for plasmas of tokamaks in measurements of flux and energy distribution (spectrum) of the neutron emission are discussed. Neutron emission spectroscopy (NES) is the most exacting of these diagnostics and the one least developed relative to its potential, instrumentally and functionally. The use and results of NES are reviewed to illustrate NES diagnostic functions from the beginning of fusion research in the 50's to the latest achievements in the sub-ignited plasmas at JET 1997. The advancement of NES diagnostics are projected to the next step experiments planned to be conducted close to ignition at ITER. The potential role of NES to handle several essential diagnostic functions on ITER are compared with the present plans for a neutron diagnostics complement without employment of state-of-the-art spectrometry methods

  3. Automated plasma control with optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ward, P.P.

    1995-08-01

    Plasma etching and desmear processes for printed wiring board (PWB) manufacture are difficult to predict and control. Non-uniformity of most plasma processes and sensitivity to environmental changes make it difficult to maintain process stability from day to day. To assure plasma process performance, weight loss coupons or post-plasma destructive testing must be used. These techniques are not real-time methods however, and do not allow for immediate diagnosis and process correction. These tests often require scrapping some fraction of a batch to insure the integrity of the rest. Since these tests verify a successful cycle with post-plasma diagnostics, poor test results often determine that a batch is substandard and the resulting parts unusable. These tests are a costly part of the overall fabrication cost. A more efficient method of testing would allow for constant monitoring of plasma conditions and process control. Process anomalies should be detected and corrected before the parts being treated are damaged. Real time monitoring would allow for instantaneous corrections. Multiple site monitoring would allow for process mapping within one system or simultaneous monitoring of multiple systems. Optical emission spectroscopy conducted external to the plasma apparatus would allow for this sort of multifunctional analysis without perturbing the glow discharge. In this paper, optical emission spectroscopy for non-intrusive, in situ process control will be explored along with applications of this technique to for process control, failure analysis and endpoint determination in PWB manufacture.

  4. Infrared laser spectroscopy of molecular beams

    International Nuclear Information System (INIS)

    Presents the first successful observation of the infrared spectrum of a single, collimated (3.6 x 10-4 steradians) beam of carbon monoxide molecules sampled from a supersonic free jet expansion. The principle of the technique is to detect directly the power absorbed from a tunable infrared laser beam by the molecules of a molecular beam, using a microcalorimeter (a cyrogenic bolometer) placed a short distance downstream from the intersection of the two beams. Since infrared fluorescent lifetimes are long, the absorbed power is transferred by the molecules to the bolometer where it is detected as a change in resistance. (Auth.)

  5. Development of the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line

    International Nuclear Information System (INIS)

    The CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is a new experimental set up at the ISOLDE facility at CERN. CRIS is being constructed for high-resolution laser spectroscopy measurements on radioactive isotopes. These measurements can be used to extract nuclear properties of isotopes far from stability. The CRIS beam line has been under construction since 2009 and testing of its constituent parts have been performed using stable and radioactive ion beams, in preparation for its first on-line run. This paper will present the current status of the CRIS experiment and highlight results from the recent tests.

  6. Plasma process control with optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ward, P.P.

    1995-04-01

    Plasma processes for cleaning, etching and desmear of electronic components and printed wiring boards (PWB) are difficult to predict and control. Non-uniformity of most plasma processes and sensitivity to environmental changes make it difficult to maintain process stability from day to day. To assure plasma process performance, weight loss coupons or post-plasma destructive testing must be used. The problem with these techniques is that they are not real-time methods and do not allow for immediate diagnosis and process correction. These methods often require scrapping some fraction of a batch to insure the integrity of the rest. Since these methods verify a successful cycle with post-plasma diagnostics, poor test results often determine that a batch is substandard and the resulting parts unusable. Both of these methods are a costly part of the overall fabrication cost. A more efficient method of testing would allow for constant monitoring of plasma conditions and process control. Process failures should be detected before the parts being treated. are damaged. Real time monitoring would allow for instantaneous corrections. Multiple site monitoring would allow for process mapping within one system or simultaneous monitoring of multiple systems. Optical emission spectroscopy conducted external to the plasma apparatus would allow for this sort of multifunctional analysis without perturbing the glow discharge. In this paper, optical emission spectroscopy for non-intrusive, in situ process control will be explored. A discussion of this technique as it applies towards process control, failure analysis and endpoint determination will be conducted. Methods for identifying process failures, progress and end of etch back and desmear processes will be discussed.

  7. Light emission from particle beam induced plasma - An overview

    CERN Document Server

    Ulrich, A

    2015-01-01

    Experiments to study the light emission from plasma produced by particle beams are presented. Fundamental aspects in comparison with discharge plasma formation are discussed. It is shown that the formation of excimer molecules is an important process. This paper summarizes various studies of particle beam induced light emission and presents first results of a direct comparison of light emission induced by electron- and ion beam excitation. Both high energy heavy ion beam and low energy electron beam experiments are described and an overview over applications in the form of light sources, lasers, and ionization devices is given.

  8. Lithium isotopic analysis by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Optical emission spectroscopy has been used to discriminate isotopic composition differences in the range of 92.6% (natural isotopic mixture) to 99.7% of /sup 7/Li. A desmountable hollow-cathode lamp was employed as an emission source for the lines /sup 2/S/sub 1/2/ - /sup 2/P/sub 1/2,3/2/ (670.8 nm), the isotopic displacement (15 pm) being of the same magnitude as the fine structure. The lines were resolved with a 3.4 m Ebert-Fastie spectrograph employed in a high dispersion mode (second order of a 1180 grooves/mm grating; theoretical resolution power: 360.000;linear reciprocal dispersion:77 pm/mm). The emission characteristics of the lamp (current intensity and argon gas pressure) were previously studied with a low resolution monochromator with photoelectric detection. In the spectrograph, the resolved doublets were photographied with a 1 N emulsion; the line transmittances were measured with a recording microphotometer. A plot of the line exposure ratio vs. isotopic composition of [/sup 2/S/sub 1/2/ -/sup 2/P/sub 3/2/ (/sup 7/Li)] relative to ([/sup 2/S/sub 1/2/ - /sup 2/P/sub 1/2/ (/sup 7/Li)] + [/sup 2/S/sub 1/2/ -/sup 2/P/sub 3/2/ (/sup 6/Li)]) gave a linear analytical curve (correlation coefficient = 0.992 for N = 4) over the tested range. (M.E.L.)

  9. Molecular-beam spectroscopy of interhalogen molecules

    International Nuclear Information System (INIS)

    A molecular-beam electric-resonance spectrometer employing a supersonic nozzle source has been used to obtain hyperfine spectra of 79Br35Cl. Analyses of these spectra and of microwave spectra published by other authors have yielded new values for the electric dipole moment and for the nuclear quadrupole coupling constants in this molecule. The new constants are significantly different from the currently accepted values. Van der Waals clusters containing chlorine monofluoride have been studied under various expansion conditions by the molecular-beam electric-deflection method. The structural possibilities indicated by the results are discussed, and cluster geometries are proposed

  10. Neutral beam spectroscopy for equilibrium and stability measurements for the PEGASUS toroidal experiment (abstract)

    International Nuclear Information System (INIS)

    An optical neutral beam spectroscopy system is being designed to provide equilibrium and stability measurements for the PEGASUS toroidal experiment. Spatially localized measurements of the electron temperature and plasma density are possible by observing the intensity of the collisionally induced neutral beam fluorescence. In a helium beam, the population of the singlet levels are relatively independent of the plasma temperature compared to the triplet levels. Therefore, the ratio of intensities of a triplet transition (e.g., 33S→23P, λ=706.5 nm) to a singlet transition (e.g., 31P→21S, λ=501.6 nm) provides a measure of the local plasma temperature for the range 10 eVe<1.0 keV. The plasma density profile can be inferred from the attenuation of the beam fluorescence signal as the beam passes through the plasma. Additionally in a deuterium beam, the local plasma density can be directly inferred from the local radial gradient in the observed beam fluorescence signal. Plasma stability will be studied with localized magnetohydrodynamics measurements via beam emission spectroscopy, which otherwise is problematic for low-field spherical plasmas. copyright 1999 American Institute of Physics

  11. Optimizing 50kV hydrogen diagnostic neutral beam performance for active spectroscopy in MST

    Science.gov (United States)

    Feng, X.; Boguski, J.; Craig, D.; den Hartog, D. J.; Munaretto, S.; Nornberg, M. D.; Olivia, S.

    2015-11-01

    The 50 kV hydrogen diagnostic neutral beam on MST provides local measurements of impurity ion emission through charge exchange recombination spectroscopy (CHERS) and of core-localized magnetic field through the motional Stark effect (MSE). The beam, which was designed to provide 5A of neutral current at 50 kV to meet these needs, is currently on a test stand to accommodate diagnosis, in order to increase the reliability of beam formation, sustain a steady current of 5 amps for 20ms, and optimize the primary energy fraction. The reliability of arc formation was increased from 40% to 80% success rate with increase of cathode gas pressure from 150kPa to 200kPa, and the stability of the arc current is improved with a decrease of the insulation magnetic field. A calorimeter with 5 thermocouples is installed to measure the horizontal and vertical beam profiles as well as beam divergence. Beam energy components are quantified through Doppler-shift spectroscopy. Preliminary simulation results of the beam using the ALCBEAM code as well as a description of how changes to the beam performance can affect CHERS and MSE measurements are presented. This work is supported by the U.S. DOE.

  12. Laser spectroscopy in an lithium beam

    International Nuclear Information System (INIS)

    Full text: The absorption and fluorescence spectra were measured in a collimated and non-collimated atomic lithium beam by means of a diode laser. Spectral lines with a similar linewidth as the lines observed before in a stationary lithium vapor were observed in the non-collimated beam. The spatial structure of the gas region which emits fluorescence permits to observe in situ the hyperfine levels of lithium atoms: each level corresponds to a relatively plane and well defined region. This indicates that the atoms leave the oven following straight lines (otherwise the collisions would produce diffuse regions), which is in correspondence to the high values of the free mean path expected for the gas at this density, and the extension of the shadow left at the condensation plate. In the collimated beam (diameter D=1 mm, and divergence of 90 mrad), the absorption spectra has a width of 450 MHz (12 deg K or less), which permits the measurement of the hyperfine structure. In this case, from the absorption data we obtained ρD=2 x 1014 atoms/m2. The temperature obtained from the Doppler width is consistent with the temperature obtained from the beam geometry. The lithium atom flow was measured with a quartz thickness monitor and based on estimates of the initial oven temperature and density measurements. Fluorescence measurements have better sensitivity ab do not present problems in the base line due to etalon effects. It is possible to observe the detail structure of the side wings in the line spectra

  13. In-beam γ-ray spectroscopy of fast beams at the NSCL

    International Nuclear Information System (INIS)

    With the development of an array of highly-segmented germanium detectors, it now becomes possible to perform in-flight γ-ray spectroscopy experiments on intermediate energy beams with unprecedented γ-ray energy resolution. Presented in this report are examples of two techniques in which SeGA, the most highly-segmented operational germanium array for in-flight spectroscopy with fast beams, was used for the detection of γ rays. SeGA used in conjunction with a high-resolution magnetic spectrograph (S800) to detect the reaction residues in coincidence represents a powerful combination for in-beam γ-ray studies

  14. Polarization Studies in Fast-Ion Beam Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  15. Doppler-free spectroscopy on tantalum atomic beam

    International Nuclear Information System (INIS)

    We demonstrate the usefulness of an atomic beam source for refractory metals in Doppler-free spectroscopy. The splittings between seven hyperfine components of the weak 578.01 nm transition in TaI are measured to +- 1 MHz. The hyperfine A and B coefficients for the upper and lower level are determined from the observed splittings. (orig.)

  16. In-beam spectroscopy of 231Pa

    International Nuclear Information System (INIS)

    Information on energy levels and on E2 and M1 matrix elements in 231Pa has been obtained using conversion-electron and gamma-ray spectroscopy following the 232Th(p, 2p)231Pa reaction and Coulomb excitation of the radioactive target 231Pa by 4He and 32S ions. The results are analyzed in the framework of the rotational model, applied to the rotational band built on the 1/2-[530] Nilsson state whose 3/2- member forms the ground state of this nucleus. The deviations of the level energies from the rigidrotor values can be described by Coriolis couplings. The analysis of the Coulomb-excitation process shows that a constant set of rotational parameters Q0, gR, gK, and b can fairly well account for the measured line intensities. (orig.)

  17. In-beam spectroscopy of 110Te

    International Nuclear Information System (INIS)

    The neutron-deficient nucleus 110Te has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in α-decay, excited states in 110Te were previously unknown. The level scheme constructed from γγ-coincidence relationships is presented with tentative spin assignments up to Iπ=21-. Above spin 8+ the yrast states have negative parity. They are most likely the members of a band predominantly based on the ν(h11/2g7/2) two-quasiparticle configuration. A band crossing is observed at Iπ ∼17-. It is suggested to be caused by the alignment of two h11/2 neutrons. The cranked shell model correctly predicts the spin alignment, but fails to reproduce the observed band crossing frequency, possibly because of octupole effects. ((orig.))

  18. Electron beam emission and interaction of double-beam gyrotron

    International Nuclear Information System (INIS)

    Highlights: ► The complete electrical design of electron gun and interaction structure of double-beam gyrotron. ► EGUN code is used for the simulation of electron gun of double-beam gyrotron. ► MAGIC code is used for the simulation of interaction structure of double-beam gyrotron. ► Design validations with other codes. - Abstract: This paper presents the numerical simulation of a double-beam magnetron injection gun (DB-MIG) and beam-wave interaction for 60 GHz, 500 kW gyrotron. The beam-wave interaction calculations, power and frequency growth estimation are performed by using PIC code MAGIC. The maximum output power of 510 kW at 41.5% efficiency, beam currents of 6 A and 12 A, electron beam velocity ratios of 1.41 and 1.25 and beam voltage of 69 kV are estimated. To obtain the design parameters, the DB-MIG with maximum transverse velocity spread less than 5% is designed. The computer simulations are performed by using the commercially available code EGUN and the in-house developed code MIGANS. The simulated results of DB-MIG design obtained by using the EGUN code are also validated with another trajectory code TRAK, which are in good agreement.

  19. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    International Nuclear Information System (INIS)

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for Hα-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the Hα-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  20. Characterisation of neutral hydrogen beam by means of active balmer-a-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, C

    1999-01-01

    Neutral particle beams are used in thermal nuclear experiments for plasma heating and current drive, and as a diagnostic tool for active spectroscopy. Within the frame of this thesis eight viewing lines for H{sub {alpha}}-spectroscopy have been installed at the end of the injector to observe the fully established neutral beam. The viewing lines are all parallel to the horizontal plane and include small angles with the beam axis, in order to make use of the Doppler effect which separates the signals from the three energy components from each other and from the H{sub {alpha}}-emission of the thermal particles. A multi-Gaussian fit code has been applied to give the amplitudes, positions and widths of the Gauss shaped signals. From this data, the beam composition and, including the physics processes in the acceleration and neutralisation sections, the ion species fractions in the source have been calculated. Furthermore, the vertical density profile and an estimation of the absolute particle density distribution based on an absolute calibration resulted. From the line positions the exact acceleration voltage has been obtained. The line widths allow an estimate of the horizontal divergence. During this work, two ion sources, the 'Pagoda' and the 'Sourcette', have been investigated to obtain the ion species ratio and beam profile. The comparison of the spectroscopic with the calorimetric results gives a useful insight into the beam steering geometry. (author)

  1. Some applications of ballistic electron emission microscopy/spectroscopy

    International Nuclear Information System (INIS)

    A brief review of ballistic electron emission microscopy and spectroscopy applications is presented. Results of our ballistic electron emission spectroscopy measurements on cleaved n-GaAs are given. The threshold in ballistic current-voltage characteristic is observed at bias 1.93 V which is high above the expected threshold. Explanation of this effect is given in the frame of present theoretical results. (author)

  2. Beam line design for synchrotron spectroscopy in the VUV

    International Nuclear Information System (INIS)

    The character of the radiation source provided by an electron storage ring is briefly reviewed from the point of view of utilization for VUV spectroscopy. The design of beam line components is then considered with special reference to the problems of contamination of optical surfaces and vacuum protection. The issues involved in designing mirrors for use with storage rings are considered with emphasis on the questions of power dissipation, image quality and materials selection

  3. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    International Nuclear Information System (INIS)

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation

  4. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V. [Budker Institute of Nuclear Physics, SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2015-11-15

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

  5. On-line laser spectroscopy with thermal atomic beams

    CERN Document Server

    Thibault, C; De Saint-Simon, M; Duong, H T; Guimbal, P; Huber, G; Jacquinot, P; Juncar, P; Klapisch, Robert; Liberman, S; Pesnelle, A; Pillet, P; Pinard, J; Serre, J M; Touchard, F; Vialle, J L

    1981-01-01

    On-line high resolution laser spectroscopy experiments have been performed in which the light from a CW tunable dye laser interacts at right angles with a thermal atomic beam. /sup 76-98/Rb, /sup 118-145 /Cs and /sup 208-213/Fr have been studied using the ionic beam delivered by the ISOLDE on-line mass separator at CERN while /sup 30-31/Na and /sup 38-47/K have been studied by setting the apparatus directly on-line with the PS 20 GeV proton beam. The principle of the method is briefly explained and some results concerning nuclear structure are given. The hyperfine structure, spins and isotope shifts of the alkali isotopes and isomers are measured. (8 refs).

  6. Controllable optical emission spectroscopy diagnostic system for analysis of process chemistries

    International Nuclear Information System (INIS)

    Optical emission spectroscopy (OES) diagnostics have been employed for many years in plasma etch end point detection schemes. Unfortunately some newer process systems have much lower optical emission or limited optical access. To overcome such limitations, an OES diagnostic system making use of variable e-beam has been developed. That system is described and initial experimental results are presented. A strong correlation is observed between the optical emission intensity and e-beam current, a measurable electrical parameter. This correlation offers means to normalize optical signal and to be used as a feedback input to the electronics that control the plasma source. In addition there is a measurable response from the different lines due to energy of the electrons, indicating a new degree of freedom in the diagnostic that can be tapped for more precise analysis of end point.

  7. Field emission cathode for high power beams

    International Nuclear Information System (INIS)

    Field emission is identified as the mechanism responsible for high current emission (50 A/cm2 at 3000K) from a dispenser-type cathode. This cathode has advantages for high power operation, and should be suitable for practical applications. (author)

  8. Spectroscopy of flame emission temperature measurement

    International Nuclear Information System (INIS)

    In this study laser induced fluorescence technique is applied to bunsen burner flame.The emission spectra of the bunsen burner which consist visible and infrared bands coming from exited CH and H2O vapor molecules in butane/air flame, were recorded.The transition probability of the lines was calculated.The ratio of the emission intensity peaks was used for the estimation of the local temperature in different positions above the primary reaction zone. It was shown that the ratio of emission lines corresponding to λ1 and λ2 changes smoothly with temperature, which makes valid the empirically obtained relationship.This technique is used as a thermometer to determine different temperatures remotely. This is necessarily needed for measuring high temperatures in certain industries.(Author)

  9. Some results of Auger spectroscopy and emission spectroscopy applied to impregnated cathodes

    International Nuclear Information System (INIS)

    A study of impregnated cathodes using combined Auger spectroscopy and emission microscopy shows that a realistic pressures regions of thick-film coverage emit more strongly than monolayer regions. The presence of sulphur and phosphorus on the surface of dispenser cathodes has been correlated with poor emission. These contaminants may be removed by heating cathodes in oxygen, a process which increases substantially the emission available from poor cathodes. (orig.)

  10. Emission of Type II Radio Bursts – Single-Beam Versus Two-Beam Scenario

    OpenAIRE

    Ganse, U.; Kilian, P.; Vainio, R.; Spanier, F.

    2012-01-01

    The foreshock region of a CME shock front, where shock accelerated electrons form a beam population in the otherwise quiescent plasma is generally assumed to be the source region of type II radio bursts. Nonlinear wave interaction of electrostatic waves excited by the beamed electrons are the prime candidates for the radio waves' emission. To address the question whether a single, or two counterpropagating beam populations are a requirement for this process, we have conducted 2.5D particle in...

  11. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Diaz, M; Ponce, L; Arronte, M; Flores, T [Laboratorio TecnologIa Laser, CICATA-IPN, Unidad Altamira, Carretera Tampico-Puerto Ind. Altamira, 89600, TAMPS (Mexico)

    2007-04-15

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  12. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    International Nuclear Information System (INIS)

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained

  13. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Science.gov (United States)

    Peña-Díaz, M.; Ponce, L.; Arronte, M.; Flores, T.

    2007-04-01

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  14. Practical and research aspects of beam-foil spectroscopy

    International Nuclear Information System (INIS)

    The application of a heavy-ion accelerator to research in beam-foil spectroscopy requires certain capital equipment which is somewhat unorthodox when viewed from the standpoint of conventional, low-energy nuclear physics. It is necessary that people who wish to expand their accelerator work to include beam-foil studies understand the nature and cost of such major apparatus. We will survey the equipment needs, starting with the particle analyzer at the output of the accelerator and including the equipment used in a variety of beam-foil experiments. Electronic and computer devices will not be discussed since they are essentially identical with those employed in nuclear studies. Considerable attention will be given to optical spectrometers and spectographs including simple instruments which might be used by a laboratory just getting started in beam-foil research, or which has limited financial resources. Attention will be given to the production and use of the exciter foils. We will then discuss some typical beam-foil experiments having to do with the excitation, detection, and analysis of spectral lines from electronic levels in multiply-ionized atoms, and also with the measurement of the mean lives of such levels. Finally, we will review some of the special properties of the beam-foil light source as regards the population of the magnetic sub-states of a given level. Recent work on the character of the emitted light will be presented. That work will deal specifically with the origin of the polarization of the light. The relevant experiments involve varying the angle between the plane of the exciter foil and the particle velocity. (author)

  15. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  16. Nuclear spectroscopy using direct reactions of RI beams

    International Nuclear Information System (INIS)

    The α inelastic scatterings and the (α,t) reaction on exotic nuclei at 50-60 A MeV are discussed. A new multipole decomposition analysis taking into account the angular correlation of decaying process originated from the alignments of the residual nucleus is applied for a study of cluster states in 12Be. The proton transfer reaction on the 12Be nucleus populates a possible proton single-particle state bound by a deformed core in the 13B nucleus of which ground state is spherical.For a new spectroscopy of nuclei using intense RI beams at RIBF, we started the SHARAQ project where a high-resolution SHARAQ spectrometer is being constructed together with a high-resolution secondary beam line. Physics motivation and the specification of the spectrometer are presented

  17. Evaluation of two-beam spectroscopy as a plasma diagnostic

    International Nuclear Information System (INIS)

    A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler

  18. Atomic lifetime measurements by beam-gas-dye laser spectroscopy

    Science.gov (United States)

    Schmoranzer, H.; Volz, U.

    1993-01-01

    Beam-gas-dye laser spectroscopy as a precise, cascade-free and collision-free method for measuring atomic lifetimes and individual oscillator strengths is described. Its recent application to fine-structure levels of the KrI 5p configuration is reported. The experimental uncertainty is reduced by one order of magnitude, with respect to previous work, down to 0.3% (1σ). The discussion of these results in comparison with experimental and theoretical ones from the literature underlines the precision of the method and its potential to guide future theoretical developments.

  19. Probing Local Environments by Time-Resolved Stimulated Emission Spectroscopy

    OpenAIRE

    Ana Rei; Graham Hungerford; Michael Belsley; Ferreira, M. Isabel C.; Peter Schellenberg

    2012-01-01

    Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI (4-(4-(dimethylamino)styryl)-N-methyl-pyridinium iodide) in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this p...

  20. Absorption and Emission Spectroscopy of a Lasing Material: Ruby

    Science.gov (United States)

    Esposti, C. Degli; Bizzocchi, L.

    2007-01-01

    Ruby is a crystalline material, which comes very expensive and is of great significance, as it helped in the creation of first laser. An experiment to determine the absorption and emission spectroscopy, in addition to the determination of the room-temperature lifetime of the substance is being described.

  1. Nonlinear ultrasonic spectroscopy and acoustic emission in SHM of aircrafts

    Czech Academy of Sciences Publication Activity Database

    Převorovský, Zdeněk; Chlada, Milan; Krofta, Josef

    2012-01-01

    Roč. 2012, SI (2012), s. 36-40. ISSN 1213-3825 R&D Projects: GA MPO(CZ) FR-TI1/274 Institutional support: RVO:61388998 Keywords : NDT * structural health monitoring * acoustic emission * nonlinear elastic wave spectroscopy * time reversal mirrors Subject RIV: BI - Acoustics

  2. Diamond Analyzed by Secondary Electron Emission Spectroscopy

    Science.gov (United States)

    Krainsky, Isay L.

    1998-01-01

    Diamond is a promising semiconductor material for novel electronic applications because of its chemical stability and inertness, heat conduction properties, and so-called negative electron affinity (NEA). When a surface has NEA, electrons generated inside the bulk of the material are able to come out into the vacuum without any potential barrier (work function). Such a material would have an extremely high secondary electron emission coefficient o, very high photoelectron (quantum) yield, and would probably be an efficient field emitter. Chemical-vapor-deposited (CVD) polycrystalline diamond films have even more advantages than diamond single crystals. Their fabrication is relatively easy and inexpensive, and they can be grown with high levels of doping--consequently, they can have relatively high conductivity. Because of these properties, diamond can be used for cold cathodes and photocathodes in high-power electronics and in high-frequency and high-temperature semiconductor devices.

  3. Intense proton beam source for ITER neutral-beam spectroscopy diagnostics

    International Nuclear Information System (INIS)

    An intense proton beam has been developed to evaluate a gas-cell neutralizer for use in an intense-neutral beam source for Tokomak Spectroscopy diagnostics. The allowed energy range of the proton stream is determined to be 50 to 70 keV from neutralization and reionization cross-sections and from the alpha particle charge exchange recombination intensity as a function of energy (baseline diagnostic). The neutralization evaluation source uses a flashover anode, magnetized, ion-diode. Neutral probes sensitive to energetic atomic and molecular hydrogen, developed to evaluate neutralizer performance, show neutral fluence from the ion-diode during the beam pulse. An array of Rogowski current probes, used to study the evolution of the current path, suggests that expansion of the anode plasma along the radial insulating magnetic field leads to impedance collapse

  4. Multiphoton Ionization Detection in Collinear Laser Spectroscopy of Isolde Beams

    CERN Multimedia

    2002-01-01

    The experiments using the multiphoton ionization technique have been continued in the beginning of 1990 with stable beam tests on the modified apparatus and with another radioactive beam time on Yb. Higher laser power and an increased vacuum in the ionization region (see figure) yielded a further gain in sensitivity, mainly due to the better suppression of the background ions produced in rest gas collisions. For even Yb isotopes we have now reached a detection efficiency of $\\epsilon$~=~1~x~10$^{-5}$ ions per incoming atom at a background count rate of 30~ions from a beam of 5~x~10$^9$. This sensitivity was high enough for spectroscopy on $^{157}$Yb, where the typical ISOLDE yield of 5~x~10$^7$Yb ions is covered by an isobaric contamination of more than 10$^{10}$ ions. Measurements have also been performed on $^{175}$Yb. These give the first precise value for the magnetic moment of this isotope, $\\mu$~=~0.766(8)$ mu _{N} $, which agrees rather well with the magnetic moment of the isotone $^{177}$Hf. The isoto...

  5. Electron cyclotron emission spectroscopy on thermonuclear plasmas

    International Nuclear Information System (INIS)

    Analysis of electron cyclotron emission (ECE) enables one to infer the radial profile of the electron temperature in tokamaks. The Dutch FOM institute for plasma physics has designed, built, installed and operated a grating polychromator for ECE measurements at JET. This thesis deals with a few instrumental aspects of this project and with applications of ECE measurements in tokamak physics studies. Ch. 3 and 4 deal with the wave transport in ECE systems. In Ch. 3 a method is developed to infer the mode conversion, which is a source for transmission losses, in a waveguide component from the antenna pattern of its exit aperture. In Ch. 4 the design and manufacture of the waveguide transition system to the grating polychromator are described. In Ch. 5 a method is reported for calibration of the spectrometers, based on the use of a microwave source which simulates a large area blackbody of very high temperature. The feasibility of the method is tested by applying it to two different ECE systems. In Ch. 6 a study of heat pulse propagation in tokamak plasma's, based on measurement of the electron temperature with the grating polychromator, is presented. 105 refs.; 48 figs.; 8 tabs

  6. A Cavity Ring-Down Spectroscopy Mercury Continuous Emission Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Christopher C. Carter

    2004-12-15

    The Sensor Research & Development Corporation (SRD) has undertaken the development of a Continuous Emissions Monitor (CEM) for mercury based on the technique of Cavity Ring-Down Spectroscopy (CRD). The project involved building an instrument for the detection of trace levels of mercury in the flue gas emissions from coal-fired power plants. The project has occurred over two phases. The first phase concentrated on the development of the ringdown cavity and the actual detection of mercury. The second phase dealt with the construction and integration of the sampling system, used to carry the sample from the flue stack to the CRD cavity, into the overall CRD instrument. The project incorporated a Pulsed Alexandrite Laser (PAL) system from Light Age Incorporated as the source to produce the desired narrow band 254 nm ultra-violet (UV) radiation. This laser system was seeded with a diode laser to bring the linewidth of the output beam from about 150 GHz to less than 60 MHz for the fundamental beam. Through a variety of non-linear optics the 761 nm fundamental beam is converted into the 254 nm beam needed for mercury detection. Detection of the mercury transition was verified by the identification of the characteristic natural isotopic structure observed at lower cavity pressures. The five characteristic peaks, due to both natural isotopic abundance and hyperfine splitting, provided a unique identifier for mercury. SRD scientists were able to detect mercury in air down below 10 parts-per-trillion by volume (pptr). This value is dependent on the pressure and temperature within the CRD cavity at the time of detection. Sulfur dioxide (SO{sub 2}) absorbs UV radiation in the same spectral region as mercury, which is a significant problem for most mercury detection equipment. However, SRD has not only been able to determine accurate mercury concentrations in the presence of SO{sub 2}, but the CRD instrument can in fact determine the SO{sub 2} concentration as well. Detection of

  7. Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission.

    Science.gov (United States)

    Chrystal, C; Burrell, K H; Grierson, B A; Pace, D C

    2015-10-01

    Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination (CER) diagnostic at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain information about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. The methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access. PMID:26520957

  8. Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission

    Energy Technology Data Exchange (ETDEWEB)

    Chrystal, C. [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Burrell, K. H.; Pace, D. C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2015-10-15

    Neutral beam injection is used in tokamaks to heat, apply torque, drive non-inductive current, and diagnose plasmas. Neutral beam diagnostics need accurate spatial calibrations to benefit from the measurement localization provided by the neutral beam. A new technique has been developed that uses in situ measurements of neutral beam emission to determine the spatial location of the beam and the associated diagnostic views. This technique was developed to improve the charge exchange recombination (CER) diagnostic at the DIII-D tokamak and uses measurements of the Doppler shift and Stark splitting of neutral beam emission made by that diagnostic. These measurements contain information about the geometric relation between the diagnostic views and the neutral beams when they are injecting power. This information is combined with standard spatial calibration measurements to create an integrated spatial calibration that provides a more complete description of the neutral beam-CER system. The integrated spatial calibration results are very similar to the standard calibration results and derived quantities from CER measurements are unchanged within their measurement errors. The methods developed to perform the integrated spatial calibration could be useful for tokamaks with limited physical access.

  9. Probing Local Environments by Time-Resolved Stimulated Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ana Rei

    2012-01-01

    Full Text Available Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI (4-(4-(dimethylaminostyryl-N-methyl-pyridinium iodide in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this paper show that time-resolved stimulated emission of DASPMI is a suitable means to probe the viscosity of local environments. Having the advantage of a higher time resolution, stimulated emission can provide information that is complementary to that obtained from fluorescence decay measurements, making it feasible to probe systems with lower viscosity.

  10. Emission Spectroscopy of the 4X Source Discharge With and Without N2 Gas

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Horace Vernon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-14

    This tech note summarizes the December, 1988 emission spectroscopy measurements made on the 4X source discharge with and without N₂ gas added to the H + Cs discharge. This study is motivated by the desire to understand why small amounts of N₂ gas added to the source discharge results in a reduction in the H⁻ beam noise. The beneficial effect of N₂ gas on H⁻ beam noise was first discovered by Bill Ingalls and Stu Orbesen on the ATS SAS source. For the 4X source the observed effect is that when N2 gas is added to the discharge the H⁻ beam noise is reduced about a factor of 2.

  11. Emission Line Imaging and Spectroscopy of Distant Galaxies

    DEFF Research Database (Denmark)

    Zabl, Johannes Florian

    probe for the gas surrounding a galaxy. Around some objects the extended Ly αemission is so strong that it can be detected for individual objects. In this thesis extremely deep VLT/XSHOOTER rest-frame far-UV spectroscopy is presented for Himiko, a gigantic Ly α emitter at redshift z = 6.6 or a time when...... Ly α emission is to weak to be detected for individual objects, stacking analysis is required. We performed such an analysis with an independent sample and find a halo consistent with measurements at higher redshifts....

  12. Infrared laser-induced breakdown spectroscopy emissions from energetic materials

    Science.gov (United States)

    Yang, Clayton S.; Brown, E.; Hommerich, Uwe; Trivedi, Sudhir B.; Samuels, Alan C.; Snyder, A. Peter

    2011-05-01

    Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological, and explosives (CBE) sensing and has significant potential for real time standoff detection and analysis. We have studied LIBS emissions in the mid-infrared (MIR) spectral region for potential applications in CBE sensing. Detailed MIR-LIBS studies were performed for several energetic materials for the first time. In this study, the IR signature spectral region between 4 - 12 um was mined for the appearance of MIR-LIBS emissions that are directly indicative of oxygenated breakdown products as well as partially dissociated and recombination molecular species.

  13. Supplemental Report: Application of Emission Spectroscopy to Monitoring Technetium

    International Nuclear Information System (INIS)

    This report provides supplemental information to an earlier report BNF-98-003-0199, ''Evaluation of Emission Spectroscopy for the On-Line Analysis of Technetium''. In this report data is included from real Hanford samples as well as for solutions spiked with technetium. This supplemental work confirms the ability of ICP-ES to monitor technetium as it breaks through an ion exchange process

  14. An Analysis of Noise on Optical Emission Spectroscopy Measurements

    OpenAIRE

    Ma, Beibei; McLoone, Sean; RINGWOOD, John; MacGearailt, Niall

    2010-01-01

    Optical Emission Spectroscopy (OES) is a non-intrusive plasma diagnostic technique that can be used to measure the chemical changes in a plasma that is in- creasingly being considered for monitoring and control of plasma etch processes. In the practice of collecting OES data for plasma etching, it is inevitable that noise is included in the measurements. The existence of noise can destroy signals or at least make the identi¯cation and interpretation of signal patterns unreliabl...

  15. Diatomic Molecular Emission Spectroscopy of Laser-induced Titanium Plasma

    International Nuclear Information System (INIS)

    Previous research regarding laser-induced breakdown spectroscopy (LIBS) of titanium normally focuses on the atomic and ionic Ti spectral transition lines. However, after a characteristic time subsequent to laser ablation, these lines are no longer discernable. During this temporal regime, the diatomic molecular transition lines of titanium monoxide (TiO) are prominent in the laser-induced plasma (LIP) emissions. TiO has long been studied in the contexts of stellar emissions, allowing for some of the molecular transition bands to be accurately computed from theory. In this research, optical emission spectroscopy (OES) of laser-induced plasma (LIP) generated by laser ablation of titanium is performed in order to infer temperature as a function of time subsequent to plasma formation. The emission spectra of the resulting ablation plume is imaged as a function of height above the sample surface. Temperatures are inferred over time delays following plasma formation ranging from 20 μs-200 μs. Computed TiO A3Φ – X3Δ, Δv = 0 transition lines are fit to spectral measurements in order to infer temperature. At tdelay = 20 μs-80 μs, the observed plume contains two luminescent regions each with a distinctly different temperature. As the plume evolves in time, the two regions combine and an overall temperature increase is observed

  16. Mid-infrared emission from laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Yang, Clayton S-C; Brown, Ei E; Hommerich, Uwe H; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

    2007-03-01

    Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique for detecting and identifying trace elemental contaminants by monitoring the visible atomic emission from small plasmas. However, mid-infrared (MIR), generally referring to the wavelength range between 2.5 to 25 microm, molecular vibrational and rotational emissions generated by a sample during a LIBS event has not been reported. The LIBS investigations reported in the literature largely involve spectral analysis in the ultraviolet-visible-near-infrared (UV-VIS-NIR) region (less than 1 microm) to probe elemental composition and profiles. Measurements were made to probe the MIR emission from a LIBS event between 3 and 5.75 microm. Oxidation of the sputtered carbon atoms and/or carbon-containing fragments from the sample and atmospheric oxygen produced CO(2) and CO vibrational emission features from 4.2 to 4.8 microm. The LIBS MIR emission has the potential to augment the conventional UV-VIS electronic emission information with that in the MIR region. PMID:17389073

  17. Pulse compression method for amplified spontaneous emission smooth beams

    International Nuclear Information System (INIS)

    In order to increase the intensity on target and the coupling efficiency, based on optical gain switching theory the paper presents a method for shortening the amplified spontaneous emission (ASE) smooth pulses. The experiment has been per- formed on EMG-150, a discharge laser in the Department of Experimental Physics, University of Szeged. As a result, the pulse bandwidth is shortened to 7.5 ns from 14.5 ns. and the uniformity of the ASE beams is not affected. (authors)

  18. Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE

    International Nuclear Information System (INIS)

    A new collinear resonant ionization spectroscopy (CRIS) beam line has recently been installed at ISOLDE, CERN utilising lasers to combine collinear laser spectroscopy and resonant ionization spectroscopy. The combined technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new programme aiming to use the CRIS technique for the separation of nuclear isomeric states for decay spectroscopy will commence in 2011. A decay spectroscopy station, consisting of a rotating wheel implantation system for alpha decay spectroscopy, and three high purity germanium detectors around the implantation site for gamma-ray detection, has been developed for this purpose. This paper will report the current status of the laser assisted decay spectroscopy set-up for the CRIS beam line.

  19. Applications and advances of positron beam spectroscopy: appendix a

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R. H., LLNL

    1997-11-05

    Over 50 scientists from DOE-DP, DOE-ER, the national laboratories, academia and industry attended a workshop held on November 5-7, 1997 at Lawrence Livermore National Laboratory jointly sponsored by the DOE-Division of Materials Science, The Materials Research Institute at LLNL and the University of California Presidents Office. Workshop participants were charged to address two questions: Is there a need for a national center for materials analysis using positron techniques and can the capabilities at Lawrence Livermore National Laboratory serve this need. To demonstrate the need for a national center the workshop participants discussed the technical advantages enabled by high positron currents and advanced measurement techniques, the role that these techniques will play in materials analysis and the demand for the data. There were general discussions lead by review talks on positron analysis techniques, and their applications to problems in semiconductors, polymers and composites, metals and engineering materials, surface analysis and advanced techniques. These were followed by focus sessions on positron analysis opportunities in these same areas. Livermore now leads the world in materials analysis capabilities by positrons due to developments in response to demands of science based stockpile stewardship. There was a detailed discussion of the LLNL capabilities and a tour of the facilities. The Livermore facilities now include the worlds highest current beam of keV positrons, a scanning pulsed positron microprobe under development capable of three dimensional maps of defect size and concentration, an MeV positron beam for defect analysis of large samples, and electron momentum spectroscopy by positrons. This document is a supplement to the written summary report. It contains a complete schedule, list of attendees and the vuegraphs for the presentations in the review and focus sessions.

  20. Estimation of Charge Exchange Recombination Emission Based on Diagnostic Neutral Beam on the Experimental Advanced Superconducting Tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-Mei; WAN Bao-Nian; WU Zhen-Wei

    2007-01-01

    Diagnostic neutral beam (DNB) attenuation and charge exchange recombination emission are estimated on EAST tokamak. Approximately 40% of the beam with the energy of 50 keV can reach the plasma centre (r = 0) for the typical parameters of the Experimental Advanced Superconducting Tokamak (EAST) plasma. Emissivities of CVI (n = 8 → 7, 529.0nm) and OVⅢ (n = 10 → 9, 607.0 nm) visible charge exchange recombination emissions based on the DNB are estimated. The emissivities of the visible bremsstrahlung emission near this wavelength are also calculated for comparison. The results show that the charge exchange recombination emission is about two orders of magnitude greater than the bremsstrahlung emission. It is theoretically indicated that the ratio of signal of charge exchange recombination spectroscopy to the noise from background bremsstrahlung emission,S/N, is large enough in the EAST tokamak with the typical designed parameters. The present results are helpful for experiment design of charge-exchange recombination spectroscopy based on the DNB in the EAST tokamak.

  1. Spectroscopy of PTCDA attached to rare gas samples: clusters vs. bulk matrices. II. Fluorescence emission spectroscopy

    OpenAIRE

    Dvorak, M.; Müller, M; Knoblauch, T.; Bünermann, O.; Rydlo, A.; Minniberger, S.; Harbich, W.; Stienkemeier, F.

    2012-01-01

    The interaction between PTCDA (3,4,9,10-perylene-tetracarboxylic-dianhydride) molecules and solid rare gas samples is studied by means of fluorescence emission spectroscopy. On the one hand, laser-excited PTCDA-doped large argon, neon and para-hydrogen clusters in comparison with PTCDA embedded in helium nanodroplets are spectroscopically characterized with respect to line broadening and shifting. A fast non-radiative relaxation is observed before a radiative decay in the electronic ground st...

  2. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    CERN Document Server

    Kwak, Sehyun; Brix, M; Ghim, Y -c

    2016-01-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy system, measuring Li I line radiation using 26 channels with ~1 cm spatial resolution and 10~20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly devel...

  3. Infrared-emission spectroscopy of CO on Ni

    International Nuclear Information System (INIS)

    We report the first observation of thermally emitted infrared radiation from vibrational modes of molecules adsorbed on clean, single-crystal metal surfaces. The observation of emission from CO adsorbed on Ni demonstrates the surface sensitivity of a novel apparatus for infrared vibrational spectroscopy, with a resolution of 1 to 15 cm-1 over the frequency range from 330 to 3000 cm-1. A liquid-helium-cooled grating spectrometer measures the thermal radiation from a room-temperature, single-crystal sample, which is mounted in an ultrahigh-vacuum system. Measurements of frequencies and linewidths of CO on a single-crystal Ni sample, as a function of coverage, are discussed

  4. Emission spectroscopy of ECRH non-axisymmetric helium mirror plasmas

    International Nuclear Information System (INIS)

    In this experiment emission spectroscopy in the 3000 to 5000 Angstrom range has been utilized to determine the electron temperature of helium plasmas produced by the Michigan Mirror Machine (MIMI). The plasma is generated and heated by whistler-mode electron-cyclotron resonance waves at 7.43 GHz and 500 Watts power in 400 μs pulses. Gas is puffed into the mid-plane region where a quartz window is used to observe the plasma. The plasma is viewed in a direction perpendicular to the mirror axis

  5. Emission Moessbauer spectroscopy of NiTi shape memory alloy

    International Nuclear Information System (INIS)

    The emission Moessbauer study on NiTi SMA (Shape Memory Alloy) is first reported. The 51.6 at% Ni-Ti alloy was provided by Shanghai Institute of steel and Iron Research. The emitter (also samples in this experiment) was produced by the nuclear reaction 58Ni(p,2p) 57Co in which a small amount of 58Ni was transformed to 57Co. The emitter Moessbauer spectra were measured after the sample was water quenched from 700 degree C for 30 min and aged at 500 degree C for 60 min and isochronal annealed in different temperature. Meantime the TEM observation and resistivity measure were also performed for the same material in the same heat treatment conditions. This work indicates that emission Moessbauer spectroscopy can be used to study the micro-mechanism of NiTi SMA

  6. Spectroscopy of PTCDA attached to rare gas samples: clusters vs. bulk matrices. II. Fluorescence emission spectroscopy

    CERN Document Server

    Dvorak, M; Knoblauch, T; Bünermann, O; Rydlo, A; Minniberger, S; Harbich, W; Stienkemeier, F

    2012-01-01

    The interaction between PTCDA (3,4,9,10-perylene-tetracarboxylic-dianhydride) molecules and solid rare gas samples is studied by means of fluorescence emission spectroscopy. On the one hand, laser-excited PTCDA-doped large argon, neon and para-hydrogen clusters in comparison with PTCDA embedded in helium nanodroplets are spectroscopically characterized with respect to line broadening and shifting. A fast non-radiative relaxation is observed before a radiative decay in the electronic ground state takes place. On the other hand, fluorescence emission studies of PTCDA embedded in bulk neon and argon matrices results in much more complex spectral signatures characterized by a splitting of the different emission lines. These can be assigned to the appearance of site isomers of the surrounding matrix lattice structure.

  7. Electron beam generated whistler emissions in a laboratory plasma

    International Nuclear Information System (INIS)

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory

  8. Electron beam generated whistler emissions in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Van Compernolle, B., E-mail: bvcomper@physics.ucla.edu; Pribyl, P.; Gekelman, W. [Department of Physics, University of California, Los Angeles (United States); An, X.; Bortnik, J.; Thorne, R. M. [Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles (United States)

    2015-12-10

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  9. Electron Cyclotron Maser Emissions from Evolving Fast Electron Beams

    CERN Document Server

    Tang, J F; Chen, L; Zhao, G Q; Tan, C M

    2016-01-01

    Fast electron beams (FEBs) are common products of solar active phenomena. Solar radio bursts are an important diagnostic tool in the understanding of FEBs as well as the solar plasma environment in which they are propagating along solar magnetic fields. In particular, the evolutions of the energy spectrum and velocity distribution of FEBs due to the interaction with the ambient plasma and field when propagating can significantly influence the efficiency and property of their emissions. In this paper, we discuss some possible evolutions of the energy spectrum and velocity distribution of FEBs due to the energy loss processes and the pitch-angle effect caused by the magnetic field inhomogeneity, and analyze the effects of these evolutions on electron cyclotron maser (ECM) emission, which is one of the most important mechanisms of producing solar radio bursts by FEBs. The results show that the growth rates all decrease with the energy loss factor $Q$, but increase with the magnetic mirror ratio $\\sigma$ as well ...

  10. Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE

    International Nuclear Information System (INIS)

    The new collinear resonant ionization spectroscopy (Cris) experiment at Isolde, Cern uses laser radiation to stepwise excite and ionize an atomic beam for the purpose of ultra-sensitive detection of rare isotopes and hyperfine structure measurements. The technique also offers the ability to purify an ion beam that is contaminated with radioactive isobars, including the ground state of an isotope from its isomer. A new program using the Cris technique to select only nuclear isomeric states for decay spectroscopy commenced last year. The isomeric ion beam is selected using a resonance within its hyperfine structure and subsequently deflected to a decay spectroscopy station. This consists of a rotating wheel implantation system for alpha and beta decay spectroscopy, and up to three high purity germanium detectors for gamma-ray detection. This paper gives an introduction to the Cris technique, the current status of the laser assisted decay spectroscopy set-up and recent results from the experiment in November 2011.

  11. Electron Cyclotron Maser Emissions from Evolving Fast Electron Beams

    Science.gov (United States)

    Tang, J. F.; Wu, D. J.; Chen, L.; Zhao, G. Q.; Tan, C. M.

    2016-05-01

    Fast electron beams (FEBs) are common products of solar active phenomena. Solar radio bursts are an important diagnostic tool for understanding FEBs and the solar plasma environment in which they propagate along solar magnetic fields. In particular, the evolution of the energy spectrum and velocity distribution of FEBs due to the interaction with the ambient plasma and field during propagation can significantly influence the efficiency and properties of their emissions. In this paper, we discuss the possible evolution of the energy spectrum and velocity distribution of FEBs due to energy loss processes and the pitch-angle effect caused by magnetic field inhomogeneity, and we analyze the effects of the evolution on electron-cyclotron maser (ECM) emission, which is one of the most important mechanisms for producing solar radio bursts by FEBs. Our results show that the growth rates all decrease with the energy loss factor Q, but increase with the magnetic mirror ratio σ as well as with the steepness index δ. Moreover, the evolution of FEBs can also significantly influence the fastest growing mode and the fastest growing phase angle. This leads to the change of the polarization sense of the ECM emission. In particular, our results also reveal that an FEB that undergoes different evolution processes will generate different types of ECM emission. We believe the present results to be very helpful for a more comprehensive understanding of the dynamic spectra of solar radio bursts.

  12. Studying Simple Molecular Ionization using Radiation Emission Spectroscopy

    Science.gov (United States)

    Proctor, Christopher; Lemmer, Kristina; Western Michigan University Aerospace LaboratoryPlasma Experiments Team

    2015-11-01

    This study focuses on radiation emission from the formation of simple molecular plasma using a DC glow discharge. The purpose is to measure the emission from argon and molecular nitrogen gas as a function of time with an optical emission spectroscopy system operating in kinetic mode as the gases go from their neutral state to ionized state. The end goal of the research is to develop a diagnostic tool that will be used to study the formation of plasma discharges from complex molecules. The kinetic mode of the CCD camera allows for fast data acquisition so that the species present and their relative concentrations as a function of time can be measured as the plasma is forming. The primary difficulty in the development of this diagnostic tool is designing a device and data analysis technique to allow for kinetic mode operation of the CCD camera. Experimental devices have been designed and built to enable the CCD to operate in kinetic mode, including a fiber optic adapter, camera mount, and twin razor blade system. The twin blades allow for the reduction of exposed pixels on the CCD camera and thereby allow the camera to store data on rows of pixels, rather than imaging the entire camera, allowing for faster data transfer. PhD in Aerospace Engineering.

  13. Beamed neutron emission driven by laser accelerated light ions

    Science.gov (United States)

    Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

    2016-05-01

    Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher–catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ∼ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher–catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

  14. Beamed neutron emission driven by laser accelerated light ions

    CERN Document Server

    Kar, S; Ahmed, H; Alejo, A; Robinson, A P L; Cerchez, M; Clarke, R; Doria, D; Dorkings, S; Fernandez, J; Mirfyazi, S R; McKenna, P; Naughton, K; Neely, D; Norreys, P; Peth, C; Powell, H; Ruiz, J A; Swain, J; Willi, O; Borghesi, M

    2015-01-01

    We report on the experimental observation of beam-like neutron emission with peak flux of the order of 10^9 n/sr, from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by high power laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of 70 degrees, with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)^1H and d(d,n)^3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons' spatial and spectral profiles are most likely related to the directionality and high energy of the projectile ions.

  15. {gamma}-ray spectroscopy with a {sup 8}He beam

    Energy Technology Data Exchange (ETDEWEB)

    Podolyak, Zs. E-mail: z.podolyak@surrey.ac.uk; Walker, P.M.; Mach, H.; France, G. de; Sletten, G.; Azaiez, F.; Casandjian, J.M.; Cederwall, B.; Cullen, D.M.; Dombradi, Zs.; Dracoulis, G.D.; Fraile, L.M.; Franchoo, S.; Fynbo, H.; Gorska, M.; Kopatch, Y.; Lane, G.J.; Mandal, S.; Milechina, L.; Molnar, J.; O' Leary, C.; Plociennik, W.; Pucknell, V.; Raddon, P.; Redon, N.; Ruchowska, E.; Stanoiu, M.; Tengblad, O.; Wheldon, C.; Wood, R

    2003-10-01

    The {sup 8}He+{sup 208}Pb reaction was studied in the first experiment with the EXOGAM germanium detector array using beam delivered by the SPIRAL facility. {gamma}-rays from direct and fusion-evaporation reactions were observed with high resolution. {gamma}-{gamma} coincidence data were obtained at a beam intensity level of 10{sup 5} {sup 8}He particles per second. Specially designed absorbers and beam detectors could further reduce the background radiation by orders of magnitude.

  16. Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity

    Science.gov (United States)

    Sarmiento, L. G.; Rudolph, D.

    2016-07-01

    With the aid of a novel combination of existing equipment - JYFLTRAP and the TASISpec decay station - it is possible to perform very clean quantum-state selective, high-resolution particle-γ decay spectroscopy. We intend to study the determination of the branching ratio of the ℓ = 9 proton emission from the Iπ = 19/2-, 3174-keV isomer in the N = Z - 1 nucleus 53Co. The study aims to initiate a series of similar experiments along the proton dripline, thereby providing unique insights into "open quantum systems". The technique has been pioneered in case studies using SHIPTRAP and TASISpec at GSI. Newly available radioactive decay modes in Geant4 simulations are going to corroborate the anticipated experimental results.

  17. [Determination of potassium in sodium by flame atomic emission spectroscopy].

    Science.gov (United States)

    Xie, C; Wen, X; Jia, Y; Sun, S

    2001-06-01

    Sodium is used as a coolant in China experiment fast reactor (CEFR). Potassium in sodium has an influence on heat property of reactor. A analytical method has been developed to determinate potassium in sodium by flame atomic emission spectroscopy. Sodium sample is dissolved by ultrasonic humidifier. The working conditions of the instrument and inTerferences from matrix sodium, acid effect and concomitant elements have been studied. Standard addition experiments are carried out with potassium chloride. The percentage recoveries are 94.7%-109.8%. The relative standard deviation is 4.2%. The analytical range accords with sodium quality control standard of CFFR. The precision corresponds to the international analytical method in sodium coolant reactor. PMID:12947670

  18. Diagnostics of laser-induced plasma by optical emission spectroscopy

    International Nuclear Information System (INIS)

    The procedure for diagnostics of laser induced plasma (LIP) by optical emission spectroscopy technique is described. LIP was generated by focusing Nd:YAG laser radiation (1.064 nm, 50 mJ, 15 ns pulse duration) on the surface of pellet containing among other elements lithium. Details of the experimental setup and experimental data processing are presented. High speed plasma photography was used to study plasma evolution and decay. From those images optimum time for plasma diagnostics is located. The electron number density, Ne, is determined by fitting profiles of Li I lines while electron temperature, Te, was determined from relative intensities of Li I lines using Boltzmann plot (BP) technique. All spectral line recordings were tested for the presence of self-absorption and then if optically thin, Abel inverted and used for plasma diagnostic purposes

  19. Project 8: Towards cyclotron radiation emission spectroscopy on tritium

    Science.gov (United States)

    Fertl, Martin; Project 8 Collaboration

    2016-03-01

    Project 8 aims to determine the neutrino mass by making a precise measurement of the β--decay of molecular tritium (Q = 18.6 keV) using the recently demonstrated the technique of cyclotron radiation emission spectroscopy (CRES). Here we discuss the production of a gas cell that fulfills the stringent requirements for cryogenic operation, safe tritium handling, a non-magnetic design, and a good microwave guide performance. The phased program that allows Project 8 to probe the neutrino mass range accessible using molecular tritium is described. Major financial support by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics to the University of Washington under Award Number DE-FG02-97ER41020 is acknowledged.

  20. Characterization of laser - induced plasmas by atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Pace, Diego M; Bertuccelli, Graciela; D' Angelo, Cristian A, E-mail: ddiaz@exa.unicen.edu.ar, E-mail: gbertucc@exa.unicen.edu.ar, E-mail: cdangelo@exa.unicen.edu.ar [Instituto de Fisica ' Arroyo Seco' , Facultad de Ciencias Exactas, U.N.C.P.B.A., Campus Universitario, Paraje Arroyo Seco, (B7000GHG) Tandil, Buenos Aires (Argentina)

    2011-01-01

    In this work, Laser-induced breakdown spectroscopy (LIBS) has been applied to characterization of plasmas generated in air at atmospheric pressure from a calcium hydroxide sample with a known concentration of Mg by using an infrared Nd:YAG laser. The influence of laser irradiance on plasma morphology and emission intensity was studied. Spatially-integrated intensities of Mg I-II lines along the line-of-sight were measured for different laser energies and delay times. The plasma temperature and the electron density were determined in each case by using and algorithm that calculates the optical thickness of the spectral lines and reproduces their experimental profiles in a framework of an homogeneous plasma in LTE that takes into account the effects of self-absorption. The results obtained showed the usefulness of this approach to provide additional information retrieved from the optical thickness of spectral lines for plasma characterization in LIBS experiments.

  1. Optical emission spectroscopy of carbon arc for nanomaterial synthesis

    Science.gov (United States)

    Vekselman, Vladislav; Stratton, Brentley; Raitses, Yevgeny

    2015-11-01

    Arc plasma assisted synthesis of carbon nanostructures is one of the most efficient and simple production methods. In spite of a long time use of this method in materials science research and industrial applications, the role of the plasma in nucleation and growth of nanostructures is not well understood. This is due to complexity of physico-chemical processes governing the plasma nanosynthesis. The objective of this work is to characterize the atmospheric pressure arc plasma used for synthesis of various carbon nanostructures. Optical emission spectroscopy was carried out to determine the distribution of temperature and density of carbon plasma in the synthesis zone as a function of arc discharge parameters. Accurate and detailed mapping of plasma parameters elucidate the general trend governing the formation of carbon nanostructures. This work was supported by DOE contract DE-AC02-09CH11466.

  2. Characterization and Infrared Emission Spectroscopy of Ball Plasmoid Discharges

    Science.gov (United States)

    Dubowsky, Scott E.; McCall, Benjamin J.

    2015-06-01

    Plasmas at atmospheric pressure serve many purposes, from ionization sources for ambient mass spectrometry (AMS) to plasma-assisted wound healing. Of the many naturally occurring ambient plasmas, ball lightning is one of the least understood; there is currently no solid explanation in the literature for the formation and lifetime of natural ball lightning. With the first measurements of naturally occurring ball lightning being reported last year, we have worked to replicate the natural phenomenon in order to elucidate the physical and chemical processes by which the plasma is sustained at ambient conditions. We are able to generate ball-shaped plasmoids (self-sustaining plasmas) that are analogous to natural ball lightning using a high-voltage, high-current, pulsed DC system. Improvements to the discharge electronics used in our laboratory and characterization of the plasmoids that are generated from this system will be described. Infrared emission spectroscopy of these plasmoids reveals emission from water and hydroxyl radical -- fitting methods for these molecular species in the complex experimental spectra will be presented. Rotational temperatures for the stretching and bending modes of H2O along with that of OH will be presented, and the non-equilibrium nature of the plasmoid will be discussed in this context. Cen, J.; Yuan, P,; Xue, S. Phys. Rev. Lett. 2014, 112, 035001. Dubowsky, S.E.; Friday, D.M.; Peters, K.C.; Zhao, Z.; Perry, R.H.; McCall, B.J. Int. J. Mass Spectrom. 2015, 376, 39-45.

  3. Explosive emission cathode plasmas in intense relativistic electron beam diodes

    International Nuclear Information System (INIS)

    An experimental study of cathode plasmas in planar diodes driven by a Sandia Nereus accelerator (270 kV, 60 kA, 70 ns), with particular attention devoted to plasma uniformity and expansion velocity, has been carried out. This diode current density was varied over a factor of ten and the rate of rise of the applied field dE/dt was varied over a factor of six. Different cathode materials, coatings, and surface roughnesses were used and the effects of glow discharge cleaning and in situ heating of the cathode were examined. Framing photography, electron beam dosimetry, perveance measurements, optical interferometry, and (spatially and temporally resolved) spectroscopy were used to diagnose the plasma uniformity, electron beam uniformity, plasma front motion, electron density, plasma composition, motion of distinct species, electron temperature, and ion (and neutral) densities. Electron beam uniformity is seen to be related to cathode plasma uniformity; this uniformity is enhanced by a high value of (the microscopic) dE/dt, which is determined both by the rise time of the applied field and by the cathode surface roughness. The significance of dE/dt is believed to be related to the screening effect of emitted electrons. The motion of the plasma front is seen to be affected by two phenomena. To begin with, all species of the cathode plasma are seen to expand at the same rate. The ions are believed to be accelerated to velocities on the order of 2 to 3 cm/μs in dense cathode spot regions at the cathode surface. Plasma expansion is also influenced by electric pressure effects, which are determined by the shape of the driving power pulse. A simple cathode plasma model, which explains the similarity of plasmas in diodes with greatly differing parameters, is proposed. The relevance of these results to inductively driven diodes, repetitively pulsed diodes, and magnetically insulated transmission lines is also discussed

  4. Effects of RF plasma processing on the impedance and electron emission characteristics of a MV beam diode

    International Nuclear Information System (INIS)

    Experiments have proven that both the surface contaminants and microstructure topography on the cathode of an electron beam diode influence impedance collapse and electron emission current. Experiments have characterized effective RF plasma processing protocols for high voltage A-K gaps using argon and argon/oxygen gas mixtures. RF processing time, feed gas pressure, and RF power were adjusted. Time resolved optical emission spectroscopy measured contaminant (hydrogen) and bulk cathode (aluminum) plasma emission versus transported axial electron beam current. Experiments utilize the Michigan Electron Long Beam Accelerator (MELBA) at parameters: V = -0.7 to minus1.0 MV, I(diode) + 3--30 kA, and pulse length = 0.4 to 1.0 microseconds. Microscopic and macroscopic E-fields on the cathode were varied to characterize the scaling of breakdown conditions for contaminants versus the bulk material of the cathode after plasma processing. Electron emission was suppressed for an aluminum cathode in a high voltage A-K gap after RF plasma processing. Experiments using a two-state low power (100W) argon/oxygen RF discharge followed by a higher power (200W) pure argon RF discharge yielded an increase in turn-on voltage required for axial current emission from 662 ± 174 kV to 981 ± 97 kV. After two-stage RF plasma processing axial current emission turn-on time was increased from 100 ± 22 nanoseconds to 175 ± 42 nanoseconds. Aluminum optical emission was delayed > 150 nanoseconds after the overshoot in voltage after two-stage RF plasma processing. Removal of hydrogen contamination on the cathode surface was observed by optical spectroscopy during the MELBA pulse. Axial and diode current were reduced 40--100% after RF plasma processing. SEM analysis suggests the aluminum cathode surface is being modified by the RF plasma discharge

  5. Acoustic Emission Behavior during Damage Development of Reinforced Concrete Beam

    International Nuclear Information System (INIS)

    As a preliminary study for applying the acoustic emission(AE) technique to assess the integrity of concrete structures, AE behavior of a reinforced concrete beam under cyclic loads of various loading stage was examined by laboratory experiments. By analyzing failure behavior of a reinforced concrete beam in the AE point of view, it was presumed that major sources of AE signals in concrete were micro-crack initiation, development of flexural and diagonal tension crack, and the friction between track surfaces. In addition, cyclic loading tests and failure test were carried out to obtain the AE responses under various loading conditions. The analysis of the signal patterns was aimed at discussing the differences between the normal signal and the abnormal signal, which represent the safe condition and the condition of developing damage, respectively. In this study, especially, the behavior of friction signals from crack surfaces, which were usually treated as noises, was considered as a typical pattern of the normal signal. As a result, significant differences between the normal and abnormal signal patterns were observed in the such parameters as the AE hit rate, magnitude of the primary or secondary AE peak, and AE response according to the sensor location. Based on the preliminary results, this new approach for practical AE application may provide a promising method for estimating the level of damage and distress in concrete structures

  6. Thermal Lensing Spectroscopy With Picosecond Pulse Trains and a New Dual Beam Configuration

    OpenAIRE

    Perry, J W; Ryabov, E. A.; Zewail, A.H.

    1982-01-01

    In this communication, we wish to report on the use of synchronously mode-locked picosecond lasers in a pump-probe configuration for TL spectroscopy. The peak power for these picosecond lasers is very high and, of course, the fundamental of the dye laser (red beam) can be efficiently (~10%) doubled in frequency (U.V. beam) by second harmonic generation in nonlinear crystals. We use this generated U.V. beam as a probe to monitor the very weak absorption of the red beam. An arrangement [4] of t...

  7. Artificial charging of spacecraft due to electron beam emission

    International Nuclear Information System (INIS)

    Electron beams on a spacecraft can be used to simulate positive charging from energetic ions whether natural (Jovian) or artificial (particle beams). Plasma environment dependent charging effects during electron beam operations on SCATHA are discussed

  8. BEAM-FOIL SPECTROSCOPY OF CHLORINE AND SULFUR IONS

    OpenAIRE

    Frot, D.; Barchewitz, R.; Cukier, M.; Dei-Cas, R.; Bruneau, J

    1987-01-01

    We report on the measurement of spectra of highly stripped chlorine and sulfur ions in the energy ranges of, respectively, 2900 - 3500 eV and 2300 - 2600 eV. The spectra have been obtained after excitation of ions travelling through a thin carbon foil . X-rays emitted by the emerging beam are analyzed with a Johanntype bent crystal spectrometer. The observation angle with respect to the beam axis is 54°. The interpretation of the spectra is performed by comparing experimental results with Mul...

  9. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  10. LOW ENERGY BEAM-GAS SPECTROSCOPY OF HIGHLY IONISED ATOMS

    OpenAIRE

    Desesquelles, J.; Denis, A.; Druetta, M.; Martin, S.

    1989-01-01

    Features of low energy beam-gas spectroscopic source are reviewed and compared to those of other light sources. Measurement techniques are surveyed. They include the study of wavelength of heavy multiply charged ions in visible and u.v. ranges from normal excited states, doubly excited states, high n levels and doubly excited Rydberg levels.

  11. Optical emission spectroscopy of argon and hydrogen-containing plasmas

    Science.gov (United States)

    Siepa, Sarah; Danko, Stephan; Tsankov, Tsanko V.; Mussenbrock, Thomas; Czarnetzki, Uwe

    2015-09-01

    Optical emission spectroscopy (OES) on neutral argon is applied to investigate argon, hydrogen and hydrogen-silane plasmas. The spectra are analyzed using an extensive collisional-radiative model (CRM), from which the electron density and the electron temperature (or mean energy) can be calculated. The CRM also yields insight into the importance of different excited species and kinetic processes. The OES measurements are performed on pure argon plasmas at intermediate pressure. Besides, hydrogen and hydrogen-silane plasmas are investigated using argon as a trace gas. Especially for the gas mixture discharges, CRMs for low and high pressure differ substantially. The commonly used line-ratio technique is found to lose its sensitivity for gas mixture discharges at higher pressure. A solution using absolutely calibrated line intensities is proposed. The effect of radiation trapping and the shape of the electron energy distribution function on the results are discussed in detail, as they have been found to significantly influence the results. This work was supported by the Ruhr University Research School PLUS, funded by Germany's Excellence Initiative [DFG GSC 98/3].

  12. Time resolved optical emission spectroscopy of an HPPMS coating process

    International Nuclear Information System (INIS)

    This paper deals with the time resolved optical emission spectroscopy of a high power pulse magnetron sputtering (HPPMS) physical vapour deposition coating process. With an industrial coating unit CC800/9 HPPMS (CemeCon AG, Wuerselen) a (Cr,Al,Si)N coating was deposited. During the coating process, an absolute calibrated Echelle spectrometer (ESA-3000) measured the intensities of the spectral lines of chromium (Cr), aluminium (Al) and molecular bands of nitrogen (N2). Time resolved measurements enable us to calculate different parameters such as the average velocity of sputtered Al and Cr atoms or the internal plasma parameters electron density ne and electron temperature kTe with a time resolution of 20 μs. With these parameters, we determine the ionization rates of Al, Cr, Ar and Kr atoms and the deposition densities of Al and Cr atoms. Thus simulated deposition densities of 1.75 x 1020 m-2 s-1 for chromium and 1.7 x 1022 m-2 s-1 for aluminium are reached.

  13. Optical emission spectroscopy study on deposition process of microcrystalline silicon

    Institute of Scientific and Technical Information of China (English)

    Wu Zhi-Meng; Lei Qing-Song; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (SiH*, H*α and H*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH* intensity increases with silane concentration, while the intensities of H*α and H*β increase first and then decrease. When the substrate temperature increases, the SiH* intensity decreases and the intensities of H*α and H*β are constant. The correlation between the intensity ratio of IH*α/ISiH* and the crystalline volume fraction (Xc) of films is confirmed.

  14. A Proposed Method for Measurement of Absolute Air Fluorescence Yield based on High Resolution Optical Emission Spectroscopy

    CERN Document Server

    Gika, V; Maltezos, S

    2016-01-01

    In this work, we present a method for absolute measurement of air fluorescence yield based on high resolution optical emission spectroscopy. The absolute measurement of the air fluorescence yield is feasible using the Cherenkov light, emitted by an electron beam simultaneously with the fluorescence light, as a "standard candle". The separation of these two radiations can be accomplished exploiting the "dark" spectral regions of the emission band systems of the molecular spectrum of nitrogen. In these "dark" regions the net Cherenkov light can be recorded experimentally and be compared with the calculated one. The instrumentation for obtaining the nitrogen molecular spectra in high resolution and the noninvasive method for monitoring the rotational temperature of the emission process are also described. For the experimental evaluation of the molecular spectra analysis we used DC normal glow discharges in air performed in an appropriate spectral lamp considered as an air-fluorescence light emulator. The propose...

  15. Laser spectroscopy of atomic beams of short-lived nuclei

    International Nuclear Information System (INIS)

    A possibility of performing laser-nuclear-spectroscopic experiments at qualitatively new level aimed to solve the second-glass current problem and to search T-non invariant effects in the beta-decay of atomic nuclei is discussed. The question of the increase in efficiency of the experiments, aimed to study the main characteristics of nuclei, far from the beta-stability, by means of the laser spectroscopy methods is considered. 147 refs.; 5 figs.; 1 tab

  16. Spectroscopy of Argon Excited in an Electron Beam Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2005-04-18

    Argon is one of the gases best investigated and most widely used in plasma discharge devices for a multitude of applications that range from wavelength reference standards to controlled fusion experiments. Reviewing atomic physics and spectroscopic problems in various ionization stages of Ar, the past use and future options of employing an electron beam ion trap (EBIT) for better and more complete Ar data in the x-ray, EUV and visible spectral ranges are discussed.

  17. Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

    CERN Multimedia

    Marinova, K P

    2002-01-01

    Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...

  18. Optimization of In-Beam Positron Emission Tomography for Monitoring Heavy Ion Tumor Therapy

    OpenAIRE

    Vieira Crespo, Paulo Alexandre

    2010-01-01

    In-beam positron emission tomography (in-beam PET) is currently the only method for an in-situ monitoring of highly tumor-conformed charged hadron therapy. In such therapy, the clinical effect of deviations from treatment planning is highly minimized by implementing safety margins around the tumor and selecting proper beam portals. Nevertheless, in-beam PET is able to detect eventual, undesirable range deviations and anatomical modifications during fractionated irradiation, to verify the accu...

  19. Workshop on Thermal Emission Spectroscopy and Analysis of Dust, Disk, and Regoliths

    Science.gov (United States)

    Sprague, Ann L. (Editor); Lynch, David K. (Editor); Sitko, Michael (Editor)

    1999-01-01

    This volume contains abstracts that have been accepted for presentation at the workshop on Thermal Emission Spectroscopy and analysis of Dust, Disks and Regoliths, held April 28-30, 1999, in Houston Texas.

  20. Scandium oxide coated polycrystalline tungsten studied using emission microscopy and photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Thermionic electron emission from 200 to 500 nm thick coatings of scandium oxide on tungsten foil have been examined in thermionic emission microscopy, spectroscopic photoelectron microcopy, synchrotron radiation and ultraviolet photoelectron spectroscopy (UPS). A clear dependence of the scandium oxide-W electron yield on the grain orientation of the polycrystalline tungsten is observed in thermionic emission and photoelectron emission. -- Highlights: ► Polycrystalline tungsten imaged with spectroscopic thermionic emission microcopy. ► Scandium oxide coated tungsten grains observed during thermionic emission. ► Direct visualization of the surface electron yield due to oxide coatings. ► Findings related to thermionic cathodes.

  1. Optical emission and mass spectroscopy of plasma processes in reactive DC pulsed magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Bulíř, Jiří; Pokorný, Petr; Bočan, Jiří; Fitl, Přemysl; Lančok, Ján; Musil, Jindřich

    Warrendale, PA : MRS, 2009. s. 14. ISBN N. [E-MRS 2009 Spring Meeting. 08.06.2009-12.06.2009, Strasbourg] R&D Projects: GA ČR GP202/09/P324 Institutional research plan: CEZ:AV0Z10100522 Keywords : reactive pulsed magnetron sputtering * optical emission spectroscopy * mass spectroscopy * alumina Subject RIV: BH - Optics, Masers, Lasers

  2. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    International Nuclear Information System (INIS)

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc18+ yield a high-precision measurement of the 2s-2p3/2 transition energy in this system. Operation of the two-electron-beam setup at high collision energy (∼1000 eV) is established using resonances of hydrogenlike Mg11+, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F6+. (orig.)

  3. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

  4. VLF wave emissions by pulsed and dc electron beams in space. I - Spacelab 2 observations

    Science.gov (United States)

    Reeves, G. D.; Banks, P. M.; Neubert, T.; Bush, R. I.; Williamson, P. R.

    1988-01-01

    The properties of radio waves generated by electron beams in space were investigated using data from the wideband wave receiver on the Spacelab 2. The VLF observations were found to confirm the results of the STS 3/OSS-1 mission. It was found that a 1-keV electron beam injected from the orbiter produced copious broadband electromagnetic emissions. When the electron beam was square-wave modulated, narrow-band emissions at the pulsing frequency and harmonics of that frequency were produced along with the broadband emissions. The observations indicated that dc 50-mA electron beams and pulsed 50-percent duty-cycle 100-mA beams produce broadband radiation which is comparable in intensity and spectral shape at all points for which the wave field was sampled.

  5. Diagnostics of the H- ion beam on light emission in transport channel

    International Nuclear Information System (INIS)

    One experimentally studied the possibility of nondisturbing diagnostics of 2 MeV energy H- beam on the basis of light emission within the transport channel. One studied the nature of light emission of gas targets and monitoring procedure for H- ion beam parameters based on it. The light emission is recorded by two photomultipliers. It was determined that the spatial distribution and the intensity of luminescence did not vary within the whole range of working gas pressure variation. One made a conclusion that the optical image of H- ion beam at H2, He and N2 gas targets within the pressure variation range (10-6 - 10-3 Torr) was formed at direct contact of target atoms or molecules with ions. One estimated the potential capabilities of beam profiling meter on the basis of light emission within transport channel

  6. Radio frequency plasma processing effects on the emission characteristics of a MeV electron beam cathode

    International Nuclear Information System (INIS)

    Experiments have proven that surface contaminants on the cathode of an electron beam diode influence electron emission current and impedance collapse. This letter reports on an investigation to reduce parasitic cathode current loss and to increase high voltage hold off capabilities by reactive sputter cleaning of contaminants. Experiments have characterized effective radio frequency (rf) plasma processing protocols for high voltage anode endash cathode (A endash K) gaps using a two-stage argon/oxygen and argon rf plasma discharge. Time-resolved optical emission spectroscopy measures contaminant (hydrogen) and bulk cathode (aluminum) plasma emission versus transported axial electron beam current turn on. Experiments were performed at accelerator parameters: V=-0.7 to -1.1 ampersand hthinsp;MV, I(diode)=3 endash 30 ampersand hthinsp;kA, and pulse length=0.4 endash 1.0 ampersand hthinsp;μs. Experiments using a two-stage low power (100 W) argon/oxygen rf discharge followed by a higher power (200 W) pure argon rf discharge yielded an increase in cathode turn-on voltage required for axial current emission from 662±174 ampersand hthinsp;kV to 981±97 ampersand hthinsp;kV. The turn-on time of axial current was increased from 100±22 to 175±42 ampersand hthinsp;ns. copyright 1999 American Institute of Physics

  7. Cascaded two-photon spectroscopy of Yb atoms with a transportable effusive atomic beam apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Song, Minsoo; Yoon, Tai Hyun [Department of Physics, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-02-15

    We present a transportable effusive atomic beam apparatus for cascaded two-photon spectroscopy of the dipole-forbidden transition (6s{sup 2} {sup 1}S{sub 0}{r_reversible} 6s7s {sup 1}S{sub 0}) of Yb atoms. An ohmic-heating effusive oven is designed to have a reservoir volume of 1.6 cm{sup 3} and a high degree of atomic beam collimation angle of 30 mrad. The new atomic beam apparatus allows us to detect the spontaneously cascaded two-photons from the 6s7s{sup 1}S{sub 0} state via the intercombination 6s6p{sup 3}P{sub 1} state with a high signal-to-noise ratio even at the temperature of 340 Degree-Sign C. This is made possible in our apparatus because of the enhanced atomic beam flux and superior detection solid angle.

  8. Cascaded two-photon spectroscopy of Yb atoms with a transportable effusive atomic beam apparatus.

    Science.gov (United States)

    Song, Minsoo; Yoon, Tai Hyun

    2013-02-01

    We present a transportable effusive atomic beam apparatus for cascaded two-photon spectroscopy of the dipole-forbidden transition (6s(2)(1)S0↔ 6s7s (1)S0) of Yb atoms. An ohmic-heating effusive oven is designed to have a reservoir volume of 1.6 cm(3) and a high degree of atomic beam collimation angle of 30 mrad. The new atomic beam apparatus allows us to detect the spontaneously cascaded two-photons from the 6s7s(1)S0 state via the intercombination 6s6p(3)P1 state with a high signal-to-noise ratio even at the temperature of 340 °C. This is made possible in our apparatus because of the enhanced atomic beam flux and superior detection solid angle. PMID:23464193

  9. Group velocity delay spectroscopy technique for industrial monitoring of electron beam induced vapors

    Energy Technology Data Exchange (ETDEWEB)

    Benterou, J J; Berzins, L V; Sharma, M N

    1998-09-24

    Spectroscopic techniques are ideal for characterization and process control of electron beam generated vapor plumes. Absorption based techniques work well for a wide variety of applications, but are difficult to apply to optically dense or opaque vapor plumes. We describe an approach for monitoring optically dense vapor plumes that is based on measuring the group velocity delay of a laser beam near an optical transition to determine the vapor density. This technique has a larger dynamic range than absorption spectroscopy. We describe our progress towards a robust system to monitor aluminum vaporization in an industrial environment. Aluminum was chosen because of its prevalence in high performance aircraft alloys. In these applications, composition control of the alloy constituents is critical to the deposition process. Data is presented demonstrating the superior dynamic range of the measurement. In addition, preliminary data demonstrating aluminum vapor rate control in an electron beam evaporator is presented. Alternative applications where this technique could be useful are discussed. Keywords: Group velocity delay spectroscopy, optical beat signal, optical heterodyne, index of refraction, laser absorption spectroscopy, external cavity diode laser (ECDL), electron beam vaporization, vapor density, vapor phase manufacturing, process control

  10. Velvet's multi-pulsed emission and multi-pulsed electron beams

    Institute of Scientific and Technical Information of China (English)

    Xia Lian-Sheng; Zhang Huang; Chen De-Biao; Zhaug Kai-Zhi; Shi Jin-Shui; Zhang Lin-Wen

    2005-01-01

    The velvet electron emission characteristics and beams' brightness are investigated with a multi-pulsed mode. The results indicate that in the multi-pulsed mode the velvet emission is not uniform and the periphery emission is much stronger than that from the centre. The periphery emission contributes much more to the formation of the cathode plasma than the centre emission, which leads to diode impendence breakdown. The relationship between the cathode plasma expansion and the initial emittance of the cathode is deduced to describe the characteristics of the multi-pulsed vacuum diode. The emittance of the multi-pulsed beams is measured to be less than 1000mm.mrad. The brightness of the electron beams is better than 1×108A/(M·rad)2.

  11. Investigating the effect of electron emission pattern on RF gun beam quality

    Science.gov (United States)

    Rajabi, A.; Shokri, B.

    2016-05-01

    Thermionic radio frequency gun is one of the most promising choices to gain a high quality electron beam, used in the infrared free electron lasers and synchrotron radiation injectors. To study the quality of the beam in a compact electron source, the emission pattern effect on the beam dynamics should be investigated. In the presented work, we developed a 3D simulation code to model the real process of thermionic emission and to investigate the effect of emission pattern, by considering geometrical constraints, on the beam dynamics. According to the results, the electron bunch emittance varies considerably with the emission pattern. Simulation results have been validated via comparison with the well-known simulation codes such as ASTRA simulation code and CST microwave studio, as well as other simulation results in the literature. It was also demonstrated that by using a continuous wave laser beam for heating the cathode, the emission pattern full width at half maximum (FWHM) of the transverse emission distribution is proportional to FWHM of the Gaussian profile for the laser beam. Additionally, by using the developed code, the effect of wall structure around the cathode on the back bombardment effect has been studied. According to the results, for a stable operation of the RF gun, one should consider the nose cone in vicinity of the cathode surface to reduce the back-bombardment effect.

  12. Determination of thermooptical and transport parameters of ε iron(III) oxide-based nanocomposites by beam deflection spectroscopy

    Science.gov (United States)

    Korte, Dorota; Carraro, Giorgio; Maccato, Chiara; Franko, Mladen

    2015-04-01

    In this work, photothermal beam deflection (PBD) experiments have been used to characterize the thermooptical and transport properties of ε-Fe2O3-based nanocomposites. In particular, iron(III) nanostructures have been functionalized with Au, Ag and Cu nanoparticles, tailoring both their nano-organization and their chemical state. In order to elucidate the correlation between the thermooptical and transport parameters, the structural, compositional and morphological properties of Fe2O3-based systems were studied by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). It was observed that the optothermal and transport parameters were influenced by the nature and oxidation state of the nanoparticles, which can serve as a key tool to master the material properties for their application in light-assisted processes.

  13. Practical Entangled-Photon Virtual-State Spectroscopy using Intense Twin Beams

    CERN Document Server

    Svozilík, Jiří; León-Montiel, Roberto de J

    2016-01-01

    We propose a new practical approach towards ultrasensitive measurements in chemical and biological systems based on the so-called virtual-state spectroscopy technique. The proposed scheme makes use of intense twin beams generated by pump pulses with different frequency chirps to successfully extract information about the virtual states that contribute to the two-photon excitation of an absorbing medium. Interestingly, we show that our approach may enable entangled-photon absorption rates up to four orders of magnitude larger than previously reported. Because of its simplicity, our method paves the way towards the first experimental implementation of the virtual-state spectroscopy technique.

  14. First on-line results from the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line at ISOLDE

    International Nuclear Information System (INIS)

    The CRIS (Collinear Resonant Ionisation Spectroscopy) experiment at the on-line isotope separator facility, ISOLDE, CERN, has been constructed for high-sensitivity laser spectroscopy measurements on radioactive isotopes. The technique determines the magnetic dipole and electric quadrupole moments, nuclear spin and changes in mean-square charge radii of exotic nuclei via measurement of their hyperfine structures and isotope shifts. In November 2011 the first on-line run was performed using the CRIS beam line, when the hyperfine structure of 207Fr was successfully measured. This paper will describe the technique and experimental setup of CRIS and present the results from the first on-line experiment.

  15. The field emission properties of high aspect ratio diamond nanocone arrays fabricated by focused ion beam milling

    Directory of Open Access Journals (Sweden)

    Z.L. Wang, Q. Wang, H.J. Li, J.J. Li, P. Xu, Q. Luo, A.Z. Jin, H.F. Yang and C.Z. Gu

    2005-01-01

    Full Text Available High aspect ratio diamond nanocone arrays are formed on freestanding diamond film by means of focused ion beam (FIB milling technology and hot-filament chemical vapor deposition (HFCVD method. The structure and phase purity of an individual diamond nanocone are characterized by scanning electron microscopy (SEM and micro-Raman spectroscopy. The result indicates that the diamond cones with high aspect ratio and small tip apex radius can be obtained by optimizing the parameters of FIB milling and diamond growth. The diamond nanocone arrays were also used to study the electron field emission properties and electric field shielding effect, finding high emission current density, low threshold and weak shielding effect, all attributable to the high field enhancement factor and suitable cone density of the diamond nanocone emitter

  16. Electron beam-physical vapor deposition of SiC/SiO 2 high emissivity thin film

    Science.gov (United States)

    Yi, Jian; He, XiaoDong; Sun, Yue; Li, Yao

    2007-02-01

    When heated by high-energy electron beam (EB), SiC can decompose into C and Si vapor. Subsequently, Si vapor reacts with metal oxide thin film on substrate surface and formats dense SiO 2 thin film at high substrate temperature. By means of the two reactions, SiC/SiO 2 composite thin film was prepared on the pre-oxidized 316 stainless steel (SS) substrate by electron beam-physical vapor deposition (EB-PVD) only using β-SiC target at 1000 °C. The thin film was examined by energy dispersive spectroscopy (EDS), grazing incidence X-ray asymmetry diffraction (GIAXD), scanning electron microscopy (SEM), atomic force microscopy (AFM), backscattered electron image (BSE), electron probe microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS) and Fourier transformed infra-red (FT-IR) spectroscopy. The analysis results show that the thin film is mainly composed of imperfect nano-crystalline phases of 3C-SiC and SiO 2, especially, SiO 2 phase is nearly amorphous. Moreover, the smooth and dense thin film surface consists of nano-sized particles, and the interface between SiC/SiO 2 composite thin film and SS substrate is perfect. At last, the emissivity of SS substrate is improved by the SiC/SiO 2 composite thin film.

  17. Ballistic Electron Emission Microscopy/Spectroscopy on Au/Titanylphthalocyanine/GaAs Heterostructures

    International Nuclear Information System (INIS)

    In this article Au/titanylphthalocyanine/GaAs diodes incorporating ultra smooth thin films of the archetypal organic semiconductor titanylphthalocyanine (TiOPc) were investigated by Ballistic Electron Emission Microscopy/Spectroscopy (BEEM/S). Analyzing the BEEM spectra, we find that the TiOPc increases the BEEM threshold voltage compared to reference Au/GaAs diodes. From BEEM images taken we conclude that our molecular beam epitaxial (MBE) grown samples show very homogeneous transmission, compare to wet chemically manufactured organic films. The barrier height measured on the Au- TiOPc-GaAs is Vb ∼ 1.2eV, which is in good agreement with the data found in [T. Nishi, K. Tanai, Y. Cuchi, M. R. Willis, and K. Seki Chem. Phys. Lett., vol. 414, pp. 479-482, 2005.]. The results indicate that TiOPc functions as a p-type semiconductor, which is plausible since the measurements were carried out in air [K. Walzer, T. Toccoli, A. Pallaori, R. Verucchi, T. Fritz, K. Leo, A. Boschetti, and S. Iannotte Surf. Scie., vol. 573, pp. 346-358, 2004

  18. Observation of optical emission from high refractive index waveguide excited by traveling electron beam

    OpenAIRE

    Kuwamura, Yuji; Yamada, Minoru; Okamoto, Ryuichi; Kanai, Takeshi; Fares, Hesham

    2008-01-01

    A new scheme for optical emission using a high refractive index waveguide and the traveling electron beam in vacuum was demonstrated. Optical emission around wavelength of 1.5 pm was observed for electron acceleration voltage of 40KV. © 2008 Optical Society of America.

  19. Multiple stimulated emission fluorescence photoacoustic sensing and spectroscopy

    Science.gov (United States)

    Li, Gaoming; Gao, Fei; Qiu, Yishen; Feng, Xiaohua; Zheng, Yuanjin

    2016-07-01

    Multiple stimulated emission fluorescence photoacoustic (MSEF-PA) phenomenon is demonstrated in this letter. Under simultaneous illumination of pumping light and stimulated emission light, the fluorescence emission process is speeded up by the stimulated emission effect. This leads to nonlinear enhancement of photoacoustic signal while the quantity of absorbed photons is more than that of fluorescent molecules illuminated by pumping light. The electronic states' specificity of fluorescent molecular can also be labelled by the MSEF-PA signals, which can potentially be used to obtain fluorescence excitation spectrum in deep scattering tissue with nonlinearly enhanced photoacoustic detection. In this preliminary study, the fluorescence excitation spectrum is reconstructed by MSEF-PA signals through sweeping the wavelength of exciting light, which confirms the theoretical derivation well.

  20. Emission spectroscopy for coal-fired cyclone furnace diagnostics.

    Science.gov (United States)

    Wehrmeyer, Joseph A; Boll, David E; Smith, Richard

    2003-08-01

    Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained. Spectra from all cyclone burners show emission lines for the trace elements Li, Na, K, and Rb, as well as the molecular species OH and CaOH. The Ca emission line is detected at the burner end of both the fuel-rich and fuel-lean cyclone furnaces but is not detected at the outlet ends of either furnace type. Along with the disappearance of Ca is a concomitant increase in the CaOH signal at the outlet end of both types of furnaces. The OH signal strength is in general stronger when viewing at the burner end rather than the exhaust end of both the fuel-rich and fuel-lean cyclone furnaces, probably due to high, non-equilibrium amounts of OH present inside the furnace. Only one molecular species was detected that could be used as a measure of air/fuel ratio: MgOH. It was detected at the burner end of fuel-rich cyclone furnaces but not detected in fuel-lean cyclone furnaces. More direct markers of air/fuel ratio, such as CO and O2 emission, were not detected, probably due to the generally weak nature of molecular emission relative to ambient blackbody emission present in the cyclone furnaces, even at ultraviolet wavelengths. PMID:14661846

  1. Thermal Emissivity-Based Chemical Spectroscopy through Evanescent Tunneling.

    Science.gov (United States)

    Poole, Zsolt L; Ohodnicki, Paul R

    2016-04-01

    A new spectroscopic technique is presented, with which environmentalchemistry-induced thermal emissivity changes of thin films are extracted with high isolation through evanescent tunneling. With this method the hydrogen-induced emissivity changes of films of TiO2 , Pd-TiO2 , and Au-TiO2 , with properties of high conductivity, hydrogen chemisorption, and plasmonic activity, are characterized in the UV-vis and NIR wavelength ranges, at 1073 K. PMID:26901747

  2. ISOLDE beams of neutron-rich zinc isotopes yields, release, decay spectroscopy

    CERN Document Server

    Köster, U; Clausen, C; Delahaye, P; Fedosseev, V; Fraile-Prieto, L M; Gernhäuser, R; Gilles, T J; Ionan, A; Kröll, T; Mach, H; Marsh, B; Seliverstov, D M; Sieber, T; Siesling, E; Tengborn, E; Wenander, F; Van de Walle, J

    2005-01-01

    Intense radioactive ion beams of the neutron-rich zinc isotopes 69-81Zn have been produced at the isotope on-line facility ISOLDE at CERN. The combined use of spallations-neutron induced fission of 238UC_x targets and resonant laser ionization provided sufficient suppression of disturbing isobars (mainly gallium and rubidium) to perform decay spectroscopy up to 81Zn.

  3. ISOLDE beams of neutron-rich zinc isotopes: yields, release, decay spectroscopy

    International Nuclear Information System (INIS)

    Intense radioactive ion beams of the neutron-rich zinc isotopes 69-81Zn have been produced at the isotope separation on-line facility ISOLDE at CERN. The combined use of spallation-neutron induced fission of 238UCx targets and resonant laser ionization provided sufficient suppression of disturbing isobars (mainly gallium and rubidium) to perform decay spectroscopy up to 81Zn. (authors)

  4. High-Directivity Emissions with Flexible Beam Numbers and Beam Directions Using Gradient-Refractive-Index Fractal Metamaterial

    Science.gov (United States)

    Xu, He-Xiu; Wang, Guang-Ming; Tao, Zui; Cui, Tie Jun

    2014-07-01

    A three-dimensional (3D) highly-directive emission system is proposed to enable beam shaping and beam steering capabilities in wideband frequencies. It is composed of an omnidirectional source antenna and several 3D gradient-refractive-index (GRIN) lenses. To engineer a broadband impedance match, the design method for these 3D lenses is established under the scenario of free-space excitation by using a planar printed monopole. For realizations and demonstrations, a kind of GRIN metamaterial is proposed, which is constructed by non-uniform fractal geometries. Due to the non-resonant and deep-subwavelength features of the fractal elements, the resulting 3D GRIN metamaterial lenses have extra wide bandwidth (3 to 7.5 GHz), and are capable of manipulating electromagnetic wavefronts accurately, advancing the state of the art of available GRIN lenses. The proposal for the versatile highly-directive emissions has been confirmed by simulations and measurements, showing that not only the number of beams can be arbitrarily tailored but also the beam directions can be steerable. The proposal opens a new way to control broadband highly-directive emissions with pre-designed directions, promising great potentials in modern wireless communication systems.

  5. Ribbon target assembly using carbon graphite for secondary emission type beam profile monitor

    International Nuclear Information System (INIS)

    We developed a secondary emission type beam profile monitor with graphite ribbons as a beam target. The graphite is excellent in endurance against heat load, and that they are thin as 1.6-2.0 micron and low z (=6) is advantage for reducing beam loss. Furthermore, since ribbons emits larger amount of electrons than ordinal metal wires because of larger surface, the monitor has higher sensitivity. On the other hands, in case of multi-ribbon type, uniformity of secondary electron emission is required for accurate measurement. For the uniform emission, not only surface homogeneity, but also evenness for each ribbon width is needed. A suitable manufacturing method to make ribbon target from graphite-foil, and emission uniformity has been studied. (author)

  6. Shaping the spatial periodic electron beams in the system of magnetron guns with secondary emission cathodes

    CERN Document Server

    Ajzatskij, N I; Zakutin, V V; Reshetnyak, N G; Romasko, V P; Volkolupov, Yu Ya; Krasnogolovets, M A

    2001-01-01

    The study on the electron beam generation processes in the system of the magnetron guns with the secondary-emission cathodes and anodes in form of periodically positioned metallic pins is carried out. It is shown, that the beam summary current of approximately 22 A is obtained in the system, consisting of four cells, which corresponds to the quadruplicate beam current value of the one cell. The pulse capacity thereby constituted approximately 600 kW. Such beams may be applied in the multipulse microwave devices

  7. An analytical model for finite radius dual-beam mode-mismatched thermal lens spectroscopy

    Science.gov (United States)

    Sabaeian, Mohammad; Nadgaran, Hamid

    2013-10-01

    In this work, a new model for dual-beam mode-mismatch thermal lens spectroscopy is presented. The model was based on a new analytical solution of time-dependent heat equation for finite radius cylindrical samples exposed to TEM00 excitation laser beams. The Fresnel diffraction integration method was used to calculate time-dependent on-axis probe beam intensity. All aberrations in thermal lens were taken into account. The model yields accurate values for absorption coefficient and thermal diffusivity of methylene blue aqueous solution. Furthermore, the optimized mode-mismatched version of this model when applied to pure water as a very low absorbent yields its absorption coefficient and thermal diffusivity values close to literature data. In contrast to traditional model, this model does not need to omit any term in its theory to fit the experimental data.

  8. Optical emission spectroscopy observations of fast pulsed capillary discharge plasmas

    Science.gov (United States)

    Avaria, G.; Ruiz, M.; Guzmán, F.; Favre, M.; Wyndham, E. S.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present time resolved optical emission spectroscopic (OES) observations of a low energy, pulsed capillary discharage (PCD). The optical emission from the capillary plasma and plasma jets emitted from the capillary volume was recorded with with a SpectraPro 275 spectrograph, fitted with a MCP gated OMA system, with 15 ns time resolution. The discharge was operated with different gases, including argon, nitrogen, hydrogen and methane, in a repetitive pulsed discharge mode at 10-50 Hz, with, 10-12 kV pulses applied at the cathode side. The time evolution of the electron density was measured using Stark broadening of the Hβ line. Several features of the capillary plasma dynamics, such as ionization growth, wall effects and plasma jet evolution, are inferred from the time evolution of the optical emission.

  9. High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

    OpenAIRE

    de Groot, F. M. F.

    2001-01-01

    In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption process. Section II discusses 1s X-ray absorption, i.e., the K edges, and section III deals with 2p X-ray absorption, the L edges. X-ray emission is discussed in, respectively, the L edges. X-ray emis...

  10. Spectroscopy and Stark-effect of Rydberg states in Ca and Sr in an atomic beam experiment

    International Nuclear Information System (INIS)

    Rydberg states of Calcium and Strontium were excited by laser radiation in an atomic beam experiment. Such spectroscopy of the Rydberg series could be done in both elements and also the Stark effect was examined in Strontium. (BEF)

  11. Spiral-like multi-beam emission via transformation electromagnetics

    Energy Technology Data Exchange (ETDEWEB)

    Tichit, Paul-Henri, E-mail: paul-henri.tichit@u-psud.fr [IEF, Univ. Paris-Sud, CNRS, UMR 8622, 91405 Orsay Cedex (France); Burokur, Shah Nawaz, E-mail: shah-nawaz.burokur@u-psud.fr; Lustrac, André de, E-mail: andre.de-lustrac@u-psud.fr [IEF, Univ. Paris-Sud, CNRS, UMR 8622, 91405 Orsay Cedex (France); Univ. Paris-Ouest, 92410 Ville d' Avray (France)

    2014-01-14

    Transformation electromagnetics offers an unconventional approach for the design of novel radiating devices. Here, we propose an electromagnetic metamaterial able to split an isotropic radiation into multiple directive beams. By applying transformations that modify distance and angles, we show how the multiple directive beams can be steered at will. We describe transformation of the metric space and the calculation of the material parameters. Different transformations are proposed for a possible physical realization through the use of engineered artificial metamaterials. Full wave simulations are performed to validate the proposed approach. The idea paves the way to interesting applications in various domains in microwave and optical regimes.

  12. Effects of electron beam pinching on microwave emission in a vircator

    Energy Technology Data Exchange (ETDEWEB)

    Young, D.; Ishihara, O. [Texas Tech Univ., Lubbock, TX (United States); Yatsuzuka, M. [Himeji Inst. of Tech. (Japan)

    1995-12-31

    Electron beam pinching in relativistic diodes has been widely observed. This pinching of electrons is understood to be caused by the flow of ions from the anode together with the flow of electrons from the cathode. The anode flow is created by the heating of the anode by the electron beam. Such a counter flow of electrons and ions is known as a bipolar flow. A vircator experiment at the Himeji Institute of Technology suggested that microwave emission in the vircator was due to a strongly pinched electron beam caused by bipolar flow. A MAGIC particle-in-cell simulation is being developed to study the effects of electron beam pinching on microwave emission in a vircator. Cathode emission from an annular cathode is modeled in the simulation by placing a plasma on the surface of the cathode and an electric field is applied to accelerate the electrons extracted from the plasma. To model the anode emission, the anode is divided into segments. The ion current is then taken to be a fraction of the electron current through each segment. Preliminary results suggest that the pinched electron beam would form a larger virtual cathode potential inside the waveguide behind the diode which should enhance microwave production. The effect of an axially applied magnetic field will also be studied to determine if the magnetic field would suppress electron pinching and microwave emission as was observed in the Himeji experiment.

  13. Potential Sources of Gravitational Wave Emission and Laser Beam Interferometers

    OpenAIRE

    Pacheco, J. A. de Freitas

    2000-01-01

    The properties of potential gravitational wave sources like neutron stars, black holes and binary systems are reviewed, as well as the different contributions (stochastic and continuous) to the gravitational wave background. The detectability of these sources by the present generation of laser beam interferometers, which will be fully operational around 2002, is also considered.

  14. 15N-urea tracing emission spectroscopy for detecting the infection of Helicobacter pylori

    International Nuclear Information System (INIS)

    Objective: To study a noninvasive and nonradioactive method, 15N-urea tracing emission spectroscopy, for detecting the Helicobacter pylori (Hp) infection. Methods: A group of 26 patients was tested with a method of 15N-urea tracing emission spectroscopy for detecting the Hp infection. Results: Taking the bacterial culture or (and) Gram stain as a standard, the specificity, sensitivity and positive predicting rate of the test were 81%, 89% and 84%, respectively. Conclusion: The method could be considered useful for clinical practice

  15. Analysis of Aluminum Dust Cloud Combustion Using Flame Emission Spectroscopy.

    Science.gov (United States)

    Lee, Sanghyup; Noh, Kwanyoung; Yoon, Woongsup

    2015-09-01

    In this study, aluminum flame analysis was researched in order to develop a measurement method for high-energy-density metal aluminum dust cloud combustion, and the flame temperature and UV-VIS-IR emission spectra were precisely measured using a spectrometer. Because the micron-sized aluminum flame temperature was higher than 2400 K, Flame temperature was measured by a non-contact optical technique, namely, a modified two-color method using 520 and 640 nm light, as well as by a polychromatic fitting method. These methods were applied experimentally after accurate calibration. The flame temperature was identified to be higher than 2400 K using both methods. By analyzing the emission spectra, we could identify AlO radicals, which occur dominantly in aluminum combustion. This study paves the way for realization of a measurement technique for aluminum dust cloud combustion flames, and it will be applied in the aluminum combustors that are in development for military purposes. PMID:26669143

  16. Utilization of synchrotron radiation in analytical chemistry. Soft X-ray emission and absorption spectroscopy

    International Nuclear Information System (INIS)

    Synchrotron soft X-ray spectroscopy includes three major types of spectroscopy such as X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and X-ray photoelectron spectroscopy (XPS). This paper takes up XAS and XES of soft X-rays, and briefly describes the principle. XAS is roughly classified into XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure), and XANES is mainly used in the analysis based on XAS of soft X-rays. As the examples of the latest soft X-ray analyses, the following are introduced: (1) bandgap of boron implantation diamond and the local structure of boron, (2) catalytic sites in solid fuel cell carbon electrode, and (3) soft X-ray analysis under atmospheric pressure. (A.O.)

  17. Vibrational spectra of CO on Ni (100) studied by infrared emission spectroscopy

    International Nuclear Information System (INIS)

    We have developed the technique of infrared emission spectroscopy in order to observe vibrational modes of molecules adsorbed on clean, single crystal metal surfaces. A novel apparatus has been constructed which measures the emission from a single crystal sample in thermal equilibrium at room temperature. The apparatus consists of a liquid helium cooled infrared grating spectrometer coupled to an ultrahigh vacuum system equipped with surface preparation and characterization facilities. 3 references, 3 figures

  18. Infrared emissivity spectroscopy of a soda-lime silicate glass up to the melt

    OpenAIRE

    Cristiane N. Santos; Meneses, Domingos de S.; Montouillout, Valérie; Echegut, Patrick

    2012-01-01

    The short-range structure of an iron doped soda-lime glass was investigated by infrared emissivity spectroscopy from room temperature up to the melt. Quantitative information on the distribution of the Q^n tetrahedral units was obtained by fitting the emissivity spectra using a dielectric function model (DFM). The DFM is based on causal Gaussian bands, associated with the stretching motions of the silicate tetrahedra. The changes in the absorption modes are related to the activation of a dyna...

  19. X-ray emission as a diagnostic from pseudospark-sourced electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Bowes, D., E-mail: david.bowes@strath.ac.uk [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Yin, H.; He, W.; Zhang, L.; Cross, A.W.; Ronald, K.; Phelps, A.D.R. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Chen, D.; Zhang, P. [Computed Tomography Lab, School of Mathematical Sciences, Capital Normal University, Beijing 100048 (China); Chen, X.; Li, D. [Department of Electronic Engineering, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-09-15

    X-ray emission has been achieved using an electron beam generated by a pseudospark low-pressure discharge and utilised as a diagnostic for beam detection. A 300 A, 34 kV PS-sourced electron beam pulse of 3 mm diameter impacting on a 0.1 mm-thick molybdenum target generated X-rays which were detected via the use of a small, portable X-ray detector. Clear X-ray images of a micro-sized object were captured using an X-ray photodetector. This demonstrates the inducement of proton induced X-ray emission (PIXE) not only as an indicator of beam presence but also as a future X-ray source for small-spot X-ray imaging of materials.

  20. Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Mihalcea, Daniel [NIU, DeKalb; Faillace, Luigi [RadiaBeam Tech.; Panuganti, Harsha [NIU, DeKalb; Thangaraj, Jayakar C.T. [Fermilab; Piot, Philippe [NIU, DeKalb

    2015-06-01

    Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with the time-dependent Particle In Cell (PIC) code WARP.

  1. Study on suppression mechanism of electron emission from Mo grid coated with carbon film by dual ion beam deposition

    International Nuclear Information System (INIS)

    It is problematic that electrons are emitted from the Mo grid of pulsed-controlled grid traveling wave tubes, caused by the contamination of cathode evaporation material, i.e. BaO. Some studies show that a Mo grid coated with carbon can greatly suppress grid electron emission. However, the reason for the electron emission suppression is not completely clear. To understand the mechanism of electron emission suppression of a BaO/C/Mo system, carbon films were prepared on Mo substrates at room temperature by means of DIBSD (dual ion beam sputtering deposition), and BaO layers were coated by using a chemical method. Post-annealing was conducted under a flowing nitrogen ambient at 700 .deg. C for 1.5 hours. The structure of the as-deposited carbon films was evaluated by TEM, AES and Raman spectroscopy. The annealed samples, the BaO/ Mo and BaO/C/Mo systems, were analyzed by XPS. The results suggest that the chemical reaction between BaO and C at high temperature eliminates the concentrations of Ba or BaO on the surface of the C/Mo system. It can be believed that the high work function material used as the grid surface coating and elimination of BaO on its surface have a critical effect on grid electron emission suppression. Moreover, the carbon film was characterized by density, homogeneity and high adhesion, owing to the features of DIBSD.

  2. Beam emission spectroscopy studies in a H-/D- beam injector

    OpenAIRE

    Barbisan, Marco

    2015-01-01

    The limited availability of the present energetic resources and the climate changes induced by the increase of the level of CO2 in the atmosphere are pushing humanity to completely rethink the ways to produce and consume energy. In the long term, a significant contribution to the solution of the world energy issue may come from nuclear fusion: the raw materials, deuterium and lithium, are worldwide accessible and in sufficient quantity to feed the future fusion reactors for several centuries. ...

  3. Atomic Oscillator Strengths by Emission Spectroscopy and Lifetime Measurements

    Science.gov (United States)

    Wiese, W. L.; Griesmann, U.; Kling, R.; Musielok, J.

    2002-11-01

    Over the last seven years, we have carried out numerous oscillator strength measurements for some light and medium heavy elements (Musielok et al. 1995, 1996, 1997, 1999, 2000; Veres & Wiese 1996; Griesmann et al. 1997; Bridges & Wiese 1998; Kling et al. 2001; Kling & Gries- mann 2000; Bridges & Wiese to be published). Most recently we have determined numerous transitions of Mu II (Kling et al. 2001; Kling & Griesmann 2000) and are now working on Cl I (Bridges & Wiese to be published). See the summary statement at the end of the text. For the emission measurements, we have applied either a high-current wall-stabilized arc (described for example, in Musielok et al. (1999)), or a high-current hollow cathode, or a Penning discharge. The latter two sources were used for branching ratio measurements from common upper 1ev- els, while the wall-stabilized arc was operated at atmospheric pressure under the condition of partial local thermodynamic equilibrium, which allows the measurement of relative transition probabilities. Absolute data were obtained by combining the emission results with lifetime data measured by other research groups, especially the University of Hannover, with which we have closely collaborated. This group uses the laser induced fluorescence (LIF) technique. Our emission spectra were recorded for the light elements with a 2 m grating spectrometer, or, for Mu II, with an FT 700 vacuum ultraviolet Fourier transform spectrometer. The radiometric calibration was carried out with a tungsten strip lamp for the visible part of the spectrum and with a deuterium lamp for the ultraviolet. All measurements were made under optically thin conditions, which was checked by doubling the path length with a focusing mirror setup. Typical uncertainties of the measured oscillator strengths are estimated to be in the range 15%-20% (one-standard deviation). However, discrepancies with advanced atomic structure theories are sometimes much larger. In Tables 1-3 and Fig. 1, we

  4. Emission spectroscopy from an XUV laser irradiated solid target

    Czech Academy of Sciences Publication Activity Database

    Dzelzainis, T.W.J.; Khattak, F.Y.; Nagler, B.; Vinko, S.M.; Whitcher, T.; Nelson, A.J.; Lee, R. W.; Bajt, S.; Toleikis, S.; Fäustlin, R.; Tschentscher, T.; Juha, Libor; Kozlová, Michaela; Chalupský, Jaromír; Hájková, Věra; Krzywinski, J.; Soberierski, R.; Jurek, M.; Fajardo, M.; Rosmej, F.B.; Heinmann, P.; Wark, J. S.; Riley, D.

    Dordrecht: Springer, 2009 - (Ciaran, L.; Riley, D.), s. 549-555 ISBN 978-1-4020-9923-6. [International Conference on X-Ray Lasers /11th./. Belfast (GB), 17.08.2008-22.08.2008] R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024 Institutional research plan: CEZ:AV0Z10100523 Keywords : free -electron laser * XUV emission spectra * XUV laser * high-energy density Subject RIV: BH - Optics, Masers, Lasers http://www.springer.com/physics/optics/ book /978-1-4020-9923-6

  5. Glow discharge lamp: A light source for optical emission spectroscopy

    Science.gov (United States)

    Vishwanathan, K. S.; Srinivasan, V.; Nalini, S.; Mahalingam, T. R.

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emission spectrography by standardizing a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii, and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent.

  6. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C2). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  7. The effect of electron beams on cyclotron maser emission excited by lower-energy cutoffs

    Science.gov (United States)

    Zhao, G. Q.; Feng, H. Q.; Wu, D. J.

    2016-05-01

    Electron-cyclotron maser (ECM) is one of the most important emission mechanisms in astrophysics and can be excited efficiently by lower-energy cutoffs of power-law electrons. These non-thermal electrons probably propagate as a directed collimated beam along ambient magnetic fields. This paper investigates the ECM, in which the effect of electron beams is emphasized. Results show the dependence of emission properties of the ECM on the beam feature. The maximum growth rate of the extraordinary mode (X2) rapidly decreases as the beam momentum increases, while the growth rate of the ordinary mode (O1) changes slightly. In particular, the ordinary mode can overcome the extraordinary mode and becomes the fastest growth mode once the beam momentum is large enough. This research presents an extension of the conventional studies on ECM driven by lower-energy cutoffs and may be helpful to understand better the emission process of solar type I radio bursts, which are dominated by the ordinary mode emission.

  8. Velocity resolved spectroscopy of molecular hydrogen emission in NGC6240

    Science.gov (United States)

    Wright, G. S.; Geballe, T. R.; Graham, J. R.

    1993-01-01

    NGC6240 is a member of the class of luminous galaxies which emit a significant fraction of their total light in the infrared. Based on its highly disturbed morphology, Fosbury and Wall (1979) suggested that the system may be a merger of two gas rich galaxies. It has two nuclei separated by 2 arcsec which are visible in the near infrared and at radio wavelengths and CO observations show that the galaxy contains a large mass of molecular gas. Unusually strong H2 emission lines dominate the near infrared spectrum of this galaxy. The galaxy emits approximately 4x10(exp 7) solar luminosity in the 2.12 micron v = 1 to 0 S(1) line alone, an order of magnitude more than other merging or starburst galaxies. To provide a better understanding of the physical processes responsible for the H2 emission from NGC6240 we have begun a program to obtain high spectral resolution observations using the echelle in CGS4 on the UKIRT. Preliminary data which were obtained in February 1991 are presented here. It is intended to obtain further observations with twice the spatial and spectral resolution in June of this year.

  9. Ground-based NIR emission spectroscopy of HD189733b

    CERN Document Server

    Waldmann, I P; Tinetti, G; Griffith, C A; Swain, M R; Deroo, P

    2011-01-01

    Spectroscopic observations of transiting exoplanets are providing an unprecedented view of the atmospheres of planets around nearby stars. As we learn more about the atmospheres of these remote bodies, we begin to build up a clearer picture of their composition and thermal structure. Here we investigate the case of K and L band emissions of the hot-Jupiter HD 189733b. Using the SpeX instrument on the NASA IRTF, we obtained three nights of secondary eclipse data using equivalent settings for all nights. Our sample includes one night previously presented by Swain et al. (2010) which allows for comparability of results. In this publication we present and discuss in detail a greatly improved data-reduction and analysis routine. This, in conjunction with more data, allows us to increase the spectral resolution of our planetary spectrum (R ~ 170-180), leading to a better identifiability of the features present. We confirm the existence of a strong emission at ~3.3 microns which is inconsistent with LTE simulations ...

  10. Vibrational emission analysis of the CN molecules in laser-induced breakdown spectroscopy of organic compounds

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy (LIBS) of organic materials is based on the analysis of atomic and ionic emission lines and on a few molecular bands, the most important being the CN violet system and the C2 Swan system. This paper is focused in molecular emission of LIBS plasmas based on the CN (B2Σ–X2Σ) band, one of the strongest emissions appearing in all carbon materials when analyzed in air atmosphere. An analysis of this band with sufficient spectral resolution provides a great deal of information on the molecule, which has revealed that valuable information can be obtained from the plume chemistry and dynamics affecting the excitation mechanisms of the molecules. The vibrational emission of this molecular band has been investigated to establish the dependence of this emission on the molecular structure of the materials. The paper shows that excitation/emission phenomena of molecular species observed in the plume depend strongly on the time interval selected and on the irradiance deposited on the sample surface. Precise time resolved LIBS measurements are needed for the observation of distinctive CN emission. For the organic compounds studied, larger differences in the behavior of the vibrational emission occur at early stages after plasma ignition. Since molecular emission is generally more complex than that involving atomic emission, local plasma conditions as well as plume chemistry may induce changes in vibrational emission of molecules. As a consequence, alterations in the distribution of the emissions occur in terms of relative intensities, being sensitive to the molecular structure of every single material. - Highlights: • Vibrational emission of CN species in laser-induced plasmas has been investigated. • Distribution of vibrational emission of CN has been found to be time dependent. • Laser irradiance affects the vibrational distribution of the CN molecules. • Plume chemistry controls the excitation mechanisms of CN molecules in the

  11. Quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy: 1. Application to sedimentary rocks

    Science.gov (United States)

    Thorpe, Michael T.; Rogers, A. Deanne; Bristow, Thomas F.; Pan, Cong

    2015-11-01

    Thermal emission spectroscopy is used to determine the mineralogy of sandstone and mudstone rocks as part of an investigation of linear spectral mixing between sedimentary constituent phases. With widespread occurrences of sedimentary rocks on the surface of Mars, critical examination of the accuracy associated with quantitative models of mineral abundances derived from thermal emission spectra of sedimentary materials is necessary. Although thermal emission spectroscopy has been previously proven to be a viable technique to obtain quantitative mineralogy from igneous and metamorphic materials, sedimentary rocks, with natural variation of composition, compaction, and grain size, have yet to be examined. In this work, we present an analysis of the thermal emission spectral (~270-1650 cm-1) characteristics of a suite of 13 sandstones and 14 mudstones. X-ray diffraction and traditional point counting procedures were all evaluated in comparison with thermal emission spectroscopy. Results from this work are consistent with previous thermal emission spectroscopy studies and indicate that bulk rock mineral abundances can be estimated within 11.2% for detrital grains (i.e., quartz and feldspars) and 14.8% for all other mineral phases present in both sandstones and mudstones, in comparison to common in situ techniques used for determining bulk rock composition. Clay-sized to fine silt-sized grained phase identification is less accurate, with differences from the known ranging from ~5 to 24% on average. Nevertheless, linear least squares modeling of thermal emission spectra is an advantageous technique for determining abundances of detrital grains and sedimentary matrix and for providing a rapid classification of clastic rocks.

  12. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    International Nuclear Information System (INIS)

    We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors

  13. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  14. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Lastras-Martínez, A., E-mail: alm@cactus.iico.uaslp.mx, E-mail: alastras@gmail.com; Ortega-Gallegos, J.; Guevara-Macías, L. E.; Nuñez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Martínez, L. F. [Instituto de Investigación en Comunicación Optica, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, San Luis Potosí, SLP 78000 (Mexico); Lastras-Montaño, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Montaño, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)

    2014-03-01

    We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  15. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    Directory of Open Access Journals (Sweden)

    A. Lastras-Martínez

    2014-03-01

    Full Text Available We report on real time-resolved Reflectance-difference (RD spectroscopy of GaAs(001 grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  16. Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

    International Nuclear Information System (INIS)

    The article presents an analytical model to simulate experimental imperfections in the realization of an X-ray absorption spectroscopy experiment, performed in transmission or fluorescence mode. Distinction is made between sources of systematic errors on a time-scale basis, to select the more appropriate model for their handling. For short time-scale, statistical models are the most suited. For large time-scale, the model is developed for sample and beam imperfections: mainly sample inhomogeneity, sample self-absorption, beam achromaticity. The ability of this model to reproduce the effects of these imperfections is exemplified, and the model is validated on real samples. Various potential application fields of the model are then presented

  17. Characterization of ion beam modified ceramic wear surfaces using Auger electron spectroscopy

    International Nuclear Information System (INIS)

    Using Auger electron spectroscopy and secondary electron microscopy, studies have been conducted on ceramic/ceramic friction and wear couples made up of TiC and NiMo-bonded TiC cermet pins run against Si3N4 and partially stabilized zirconia disc surfaces modified by the ion beam mixing of titanium and nickel in order to determine the types of surface changes leading to the improved friction and wear behaviour of the surface modified ceramics in simulated diesel environments. The results of the surface analyses indicate that the formation of a lubricating oxide layer of titanium and nickel, is responsible for the improvement in ceramic friction and wear behaviour. The beneficial effect of this oxide layer depends on several factors, including the adherence of the surface modified layer or subsequently formed oxide layer to the disc substrate, the substrate materials, the conditions of ion beam mixing, and the environmental conditions. (author)

  18. Annealing Behaviour of Helium Bubbles in Titanium Films by Thermal Desorption Spectroscopy and Positron Beam Analysis

    Institute of Scientific and Technical Information of China (English)

    LIU Chao-Zhuo; ZHOU Zhu-Ying; SHI Li-Qun; WANG Bao-Yi; HAO Xiao-Peng; ZHAO Guo-Qing

    2007-01-01

    @@ Helium-containing Ti films are prepared using magnetron sputtering in the helium-argon atmosphere. Isochronal annealing at different temperatures for an hour is employed to reveal the behaviour of helium bubble growth. Ion beam analysis is used to measure the retained helium content. Helium can release largely when annealing above 970 K. A thermal helium desorption spectroscopy system is constructed for assessment of the evolution of helium bubbles in the annealed samples by linear heating (0.4K/s) from room temperature to 1500K. Also, Doppler broadening measurements of positron annihilation radiation spectrum are performed by using changeable energy positron beam. Bubble coarsening evolves gradually below 680K, migration and coalescence of small bubbles dominates in the range of 680-970K, and the Ostwald ripening mechanism enlarges the bubbles with a massive release above 970K.

  19. Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam

    CERN Document Server

    Jansen, Paul; Meng, Congsen; Lees, Ronald M; Janssen, Maurice H M; Ubachs, Wim; Bethlem, Hendrick L

    2013-01-01

    Recently, the extremely sensitive torsion-rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton-to-electron mass ratio over cosmological time scales. In order to improve this constraint, laboratory data of increased accuracy will be required. Here, we explore the possibility for performing high-resolution spectroscopy on methanol in a Stark-deflected molecular beam. We have calculated the Stark shift of the lower rotational levels in the ground torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to simulate trajectories through a typical molecular beam resonance setup. Furthermore, we have determined the efficiency of non-resonant multi-photon ionization of methanol molecules using a femtosecond laser pulse. The described setup is in principle suited to measure microwave transitions in CH3OH at an accuracy below 10^{-8}.

  20. Picosecond rotationally resolved stimulated emission pumping spectroscopy of nitric oxide

    International Nuclear Information System (INIS)

    Highlights: ► Stimulated emission pumping for nitric oxide was studied using picosecond lasers. ► Weak and tightly focused pulses provide sufficient energy for population transfer. ► Selective excitation at the bandhead yields strong fluorescence depletion signals. ► We observe 19% population transfer to v″ = 2 of the X2Π1/2 ground electronic state. - Abstract: Stimulated emission pumping (SEP) experiments were performed on the nitric oxide molecule in a flow cell environment using lasers with pulse widths of 17–25 ps. A lambda excitation scheme, or ‘‘pump–dump” arrangement, was employed with the pump laser tuned to the T00 vibronic band origin (λpump=226.35(1)nm) of the A2Σ+(v′ = 0, J′) ← X2Π1/2(v″ = 0, J″) and the dump laser scanned from 246–248 nm within the A2Σ+(v′ = 0, J′) → X2Π1/2(v″ = 2, J″) transition. The rotationally resolved SEP spectra were measured by observing the total fluorescence within the A2Σ+(v′ = 0, J′) → X2Π1/2(v″ = 1, J″) transition between 235 nm and 237.2 nm while scanning the dump laser wavelengths. Multiple rotational states were excited due to the broad laser bandwidth. Measurements showed that the resolved rotational structure depended on the energy and bandwidth of the applied pump and dump laser pulses. Analysis of the observed fluorescence depletion signals yielded an average percent fluorescence depletion of about 19% when λpump=226.35(1)nm and λdump=247.91(1)nm. This value reflects the percent transfer of the NO population from the A2Σ+(V′ = 0, J′) excited electronic state to the X2Π1/2(v″ = 2, J″) ground electronic state. The maximum expected depletion is 50% in the limit of dump saturation. Selective excitation of NO at the bandhead provides good spectral discrimination from the background emission and noise and unambiguously confirms the identity of the emitter.

  1. A secondary emission type beam profile monitor with carbon graphite ribbons

    International Nuclear Information System (INIS)

    We developed a secondary emission type beam profile monitor with carbon graphite ribbons as a beam target. The carbon graphite is excellent in endurance against heat load, and that they are thin as 1.6-3.0 micron and low z (=6) are advantage for reducing beam loss. Furthermore, since ribbons emits larger amount of electrons than ordinal metal wires because of larger surface, the monitor has higher sensitivity. The monitors were installed in the end of 3-50 BT and injection point of MR in J-PARC, in order to measure injection beam profiles by single passing. Normal size target has 32ch ribbons with 2 or 3 mm in width and their length is 200 mm each. In this paper, basic characteristics of the carbon graphite target and results of beam measurement are reported. (author)

  2. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge

    International Nuclear Information System (INIS)

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  3. Optical emission spectroscopy of High Power Impulse Magnetron Sputtering (HiPIMS) of CIGS thin films

    Czech Academy of Sciences Publication Activity Database

    Olejníček, Jiří; Hubička, Zdeněk; Kohout, Michal; Kšírová, Petra; Brunclíková, Michaela; Kment, Štěpán; Čada, Martin; Darveau, S.A.; Exstrom, C.L.

    New York: IEEE, 2014, s. 1666-1669. ISBN 9781479943982. [IEEE Photovoltaic Specialist Conference (PVSC 2014) /40./. Denver (US), 08.06.2014-13.06.2014] R&D Projects: GA MŠk LH12045 Institutional support: RVO:68378271 Keywords : CIGS * HiPIMS * emission spectroscopy * magnetron sputtering * thin films Subject RIV: BL - Plasma and Gas Discharge Physics

  4. Programs in Fortran language for reporting the results of the analyses by ICP emission spectroscopy

    International Nuclear Information System (INIS)

    Three programs, written in FORTRAN IV language, for reporting the results of the analyses by ICP emission spectroscopy from data stored in files on floppy disks have been developed. They are intended, respectively, for the analyses of: 1) waters, 2) granites and slates, and 3) different kinds of geological materials. (Author) 8 refs

  5. Emission Spectroscopy of OH Radical in Water-Argon Arc Plasma Jet

    Czech Academy of Sciences Publication Activity Database

    Mašláni, Alan; Sember, Viktor

    2014-01-01

    Roč. 2014, April (2014), "952138"-"952138". ISSN 2314-4920 R&D Projects: GA ČR GAP205/11/2070 Institutional support: RVO:61389021 Keywords : Emission spectroscopy * OH radical * arc plasma jet Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.538, year: 2014 http://www.hindawi.com/journals/jspec/2014/952138/abs/

  6. Detection and localization of defects in complex structures by Nonlinear Elastic Wave Spectroscopy and Acoustic Emission

    Czech Academy of Sciences Publication Activity Database

    Převorovský, Zdeněk; Chlada, Milan; Krofta, Josef; Kober, Jan; Dos Santos, S.

    Le Mans: The University of Maine in Le Mans, 2013 - (Bentahar, M.; Kenderian, S.; Green, R.). s. 95 [Internanational Symposium on Nondestructive Characterization of Materials /13./. 20.05.2013-24.05.2013, Le Mans] Institutional support: RVO:61388998 Keywords : nonlinear elastic wave spectroscopy * acoustic emission * nondestructive testing * damage initiation * civil structure Subject RIV: JS - Reliability ; Quality Management, Testing

  7. Inductively coupled plasma-atomic emission spectroscopy: The determination of trace impurities in uranium hexafluoride

    Science.gov (United States)

    Floyd, M. A.; Morrow, R. W.; Farrar, R. B.

    An analytical method has been developed for the determination of trace impurities in high-purity uranium hexafluoride using liquid-liquid extraction of the uranium from the trace impurities followed by analysis with inductively coupled plasma-atomic emission spectroscopy. Detection limits, accuracy, and precision data are presented.

  8. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    International Nuclear Information System (INIS)

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio

  9. In situ photoelectron spectroscopy of molecular-beam-epitaxy grown surfaces

    CERN Document Server

    Oshima, M; Okabayashi, J; Ono, K

    2003-01-01

    Two in situ high-resolution synchrotron radiation photoelectron spectroscopy (SRPES) systems combined with a molecular beam epitaxy (MBE) chamber for III-V compound semiconductors and a laser MBE chamber for strongly correlated oxide films, respectively, have been designed and fabricated to analyze intrinsic and surface/interface electronic structures of these unique materials. The importance of the in situ SRPES has been demonstrated by the results of 1) Si surface nanostructures, 2) GaAs surfaces/interfaces and nanostructures, 3) MnAs magnetic nanostructures, and 4) strongly-correlated La sub 1 sub - sub x Sr sub x MnO sub 3 surfaces/interfaces and superstructures.

  10. Cascade emission in electron beam ion trap plasma of W25+ ion

    Science.gov (United States)

    Jonauskas, V.; Pütterich, T.; Kučas, S.; Masys, Š.; Kynienė, A.; Gaigalas, G.; Kisielius, R.; Radžiūtė, L.; Rynkun, P.; Merkelis, G.

    2015-07-01

    Spectra of the W25+ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the 10-30 nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5-5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to 4d9 4f4 → 4f3 transitions, while 4f2 5 d → 4f3 transitions arise after the cascade emission is taken into account.

  11. Cascade emission in electron beam ion trap plasma of W$^{25+}$ ion

    CERN Document Server

    Jonauskas, V; Kučas, S; Masys, Š; Kynienė, A; Gaigalas, G; Kisielius, R; Radžiūtė, L; Rynkun, P; Merkelis, G

    2015-01-01

    Spectra of the W$^{25+}$ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the $10 - 3$ nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5 to 5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to $4d^{9} 4f^{4} \\rightarrow 4f^{3}$ transitions, while $4f^{2} 5d \\rightarrow 4f^{3}$ transitions arise after the cascade emission is taken into account.

  12. Proceeding of the workshop on gamma-ray spectroscopy utilizing heavy-ion, photon and RI beams

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Sugita, Michiaki; Hayakawa, Takehito [eds.

    1998-03-01

    Three time since 1992, we have held the symposia entitled `Joint Spectroscopy Experiments Utilizing JAERI Tandem-Booster Accelerator` at the Tokai Research Establishment. In the symposia, we have mainly discussed the plans of experiments to be done in this joint program. The joint program started in 1994. Several experiments have been made since and some new results have already come up. This symposium `Gamma-ray Spectroscopy utilizing heavy-ion, Photon and RI beams` was held at Tokai Research Establishment of JAERI. Because this symposium is the first occasion after the program started, the first purpose of the symposium is to present and discuss the experimental results so far obtained using the JAERI Tandem-Booster. The second purpose of the symposium is to discuss new possibilities of gamma-ray spectroscopy using new resources such as RI-beam and Photon-beam. The participants from RIKEN, Tohoku University and JAERI Neutron Science Research Center presented the future plans of experiments with RI-beam at each facility. Compared with these nuclear beams, photon beam provides a completely new tool for the {gamma}-ray spectroscopy, which is achieved by inverse Compton scattering between high-energy electron and laser beams. The 23 of the presented papers are indexed individually. (J.P.N.)

  13. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    Science.gov (United States)

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  14. Anisotropy resolved multidimensional emission spectroscopy (ARMES): A new tool for protein analysis.

    Science.gov (United States)

    Groza, Radu Constantin; Li, Boyan; Ryder, Alan G

    2015-07-30

    Structural analysis of proteins using the emission of intrinsic fluorophores is complicated by spectral overlap. Anisotropy resolved multidimensional emission spectroscopy (ARMES) overcame the overlap problem by the use of anisotropy, with chemometric analysis, to better resolve emission from different fluorophores. Total synchronous fluorescence scan (TSFS) provided information about all the fluorophores that contributed to emission while anisotropy provided information about the environment of each fluorophore. Here the utility of ARMES was demonstrated via study of the chemical and thermal denaturation of human serum albumin (HSA). Multivariate curve resolution (MCR) analysis of the constituent polarized emission ARMES data resolved contributions from four emitters: fluorescence from tryptophan (Trp), solvent exposed tyrosine (Tyr), Tyr in a hydrophobic environment, and room temperature phosphorescence (RTP) from Trp. The MCR scores, anisotropy, and literature validated these assignments and showed all the expected transitions during HSA unfolding. This new methodology for comprehensive intrinsic fluorescence analysis of proteins is applicable to any protein containing multiple fluorophores. PMID:26320645

  15. Time-resolved spectroscopy of spin-current emission from a magnetic insulator

    Science.gov (United States)

    Tateno, Yuma; Fukami, Masaya; Tashiro, Takaharu; Ando, Kazuya

    2016-05-01

    We demonstrate time-resolved spectroscopy of spin-current emission from a magnetic insulator using the inverse spin Hall effect (ISHE). We measured magnetic field dependence of the spin-current emission in the time domain and found that the spectral shape of the ISHE voltage changes with time. The change in the spectral shape is due to field and power dependent temporal oscillation of the spin pumping driven by parametric magnons. The observed oscillating spin-current emission driven by dipole-exchange magnons is well reproduced by a model calculation based on the S theory. In contrast, the spin-current emission driven by short-wavelength exchange magnons cannot be reproduced with this model, illustrating an important role of higher-order nonlinear effects in the spin-current emission.

  16. Surface and waveguide collection of Raman emission in waveguide-enhanced Raman spectroscopy.

    Science.gov (United States)

    Wang, Zilong; Zervas, Michalis N; Bartlett, Philip N; Wilkinson, James S

    2016-09-01

    We demonstrate Raman spectroscopy on a high index thin film tantalum pentoxide waveguide and compare collection of Raman emission from the waveguide end with that from the waveguide surface. Toluene was used as a convenient model analyte, and a 40-fold greater signal was collected from the waveguide end. Simulations of angular and spatial Raman emission distributions showed good agreement with experiments, with the enhancement resulting from efficient collection of power from dipoles near the surface into the high-index waveguide film and substrate, combined with long interaction length. The waveguide employed was optimized at the excitation wavelength but not at emission wavelengths, and full optimization is expected to lead to enhancements comparable to surface-enhanced Raman spectroscopy in robust low-cost metal-free and nanostructure-free chips. PMID:27607994

  17. Deep Spectroscopy of Ultra-Strong Emission Line Galaxies

    CERN Document Server

    Hu, Esther M; Kakazu, Yuko; Barger, Amy J

    2009-01-01

    Ultra strong emission-line galaxies (USELs) with extremely high equivalent widths (EW(H beta) > 30A) can be used to pick out galaxies of extremely low metallicity in the z=0-1 redshift range. Large numbers of these objects are easily detected in deep narrow band searches and, since most have detectable [OIII] 4363, their metallicities determined using the direct method. These large samples hold the possibility for determining if there is a metallicity floor for the galaxy population. Here we describe results of an extensive spectroscopic follow-up of the Kakazu et al. (2007) catalog of 542 USELs using the DEIMOS spectrograph on Keck, with high S/N spectra of 348 galaxies. The two lowest metallicity galaxies in our sample have 12+log(O/H)=6.97+/-0.17 and 7.25+/-0.03 -- values comparable to the lowest metallicity galaxies found to date. We determine an empirical metallicity-R23 parameter relation for our sample, and compare this to the relationship for low redshift galaxies. The determined metallicity-luminosit...

  18. New method for estimating greenhouse gas emissions from livestock buildings using open-path FTIR spectroscopy

    Science.gov (United States)

    Briz, Susana; Barrancos, José; Nolasco, Dácil; Melián, Gladys; Padrón, Eleazar; Pérez, Nemesio

    2009-09-01

    It is widely known that methane, together with carbon dioxide, is one of the most effective greenhouse gases contributing to climate global change. According to EMEP/CORINAIR Emission Inventory Guidebook1, around 25% of global CH4 emissions originate from animal husbandry, especially from enteric fermentation. However, uncertainties in the CH4 emission factors provided by EMEP/CORINAIR are around 30%. For this reason, works addressed to calculate emissions experimentally are so important to improve the estimations of emissions due to livestock and to calculate emission factors not included in this inventory. FTIR spectroscopy has been frequently used in different methodologies to measure emission rates in many environmental problems. Some of these methods are based on dispersion modelling techniques, wind data, micrometeorological measurements or the release of a tracer gas. In this work, a new method for calculating emission rates from livestock buildings applying Open-Path FTIR spectroscopy is proposed. This method is inspired by the accumulation chamber method used for CO2 flux measurements in volcanic areas or CH4 flux in wetlands and aquatic ecosystems. The process is the following: livestock is outside the building, which is ventilated in order to reduce concentrations to ambient level. Once the livestock has been put inside, the building is completely closed and the concentrations of gases emitted by livestock begin to increase. The Open-Path system measures the concentration evolution of gases such as CO2, CH4, NH3 and H2O. The slope of the concentration evolution function, dC/dt, at initial time is directly proportional to the flux of the corresponding gas. This method has been applied in a cow shed in the surroundings of La Laguna, Tenerife Island, Spain). As expected, evolutions of gas concentrations reveal that the livestock building behaves like an accumulation chamber. Preliminary results show that the CH4 emission factor is lower than the proposed by

  19. Measuring the density of a molecular cluster injector via visible emission from an electron beam

    International Nuclear Information System (INIS)

    A method to measure the density distribution of a dense hydrogen gas jet is presented. A Mach 5.5 nozzle is cooled to 80 K to form a flow capable of molecular cluster formation. A 250 V, 10 mA electron beam collides with the jet and produces Hα emission that is viewed by a fast camera. The high density of the jet, several 1016 cm-3, results in substantial electron depletion, which attenuates the Hα emission. The attenuated emission measurement, combined with a simplified electron-molecule collision model, allows us to determine the molecular density profile via a simple iterative calculation.

  20. MM-wave emission by magnetized plasma during sub-relativistic electron beam relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, I. A., E-mail: Ivanov@inp.nsk.su; Arzhannikov, A. V.; Burmasov, V. S.; Popov, S. S.; Postupaev, V. V.; Sklyarov, V. F.; Vyacheslavov, L. N. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Burdakov, A. V.; Sorokina, N. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Karl Marx Avenue, Novosibirsk 630092 (Russian Federation); Gavrilenko, D. E.; Kasatov, A. A.; Kandaurov, I. V.; Mekler, K. I.; Rovenskikh, A. F.; Trunev, Yu. A. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Kurkuchekov, V. V.; Kuznetsov, S. A. [Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Polosatkin, S. V. [Budker Institute of Nuclear Physics, 11 Lavrentjev Avenue, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, 20 Karl Marx Avenue, Novosibirsk 630092 (Russian Federation)

    2015-12-15

    There are described electromagnetic spectra of radiation emitted by magnetized plasma during sub-relativistic electron beam in a double plasma frequency band. Experimental studies were performed at the multiple-mirror trap GOL-3. The electron beam had the following parameters: 70–110 keV for the electron energy, 1–10 MW for the beam power and 30–300 μs for its duration. The spectrum was measured in 75–230 GHz frequency band. The frequency of the emission follows variations in electron plasma density and magnetic field strength. The specific emission power on the length of the plasma column is estimated on the level 0.75 kW/cm.

  1. Optical emission spectroscopy as a diagnostic for plasmas in liquids: opportunities and pitfalls

    International Nuclear Information System (INIS)

    In this contribution, optical emission spectroscopy is evaluated and thoroughly analysed as a diagnostic to characterize plasmas in and in contact with liquids. One of the specific properties of plasmas in and in contact with liquids is the strong emission of OH(A-X) and of hydrogen lines. As an example a 600 ns pulsed dc excited discharge in Ar, He and O2 bubbles in water is investigated by time resolved optical emission spectroscopy. It is shown that the production processes of excited species and the plasma kinetics strongly influence the emission spectrum. This complicates the interpretation of the spectra but provides the opportunity to derive production mechanisms from the time resolved emission. The importance of recombination processes compared with direct electron excitation processes in the production of excited states of the water fragments in plasmas with high electron densities is shown. The OH(A-X) emission spectrum illustrates that even in these highly collisional atmospheric pressure discharges the rotational population distribution deviates from equilibrium. A two-temperature fit of the OH rotational population distribution leads to realistic gas temperatures for the temperature parameter corresponding to small rotational numbers. The Hα and Hβ lines are fitted with two component profiles corresponding to two different electron densities. The obtained electron density is in the range 1021-1023 m-3. Possible complications in the interpretation of obtained temperatures and electron densities are discussed.

  2. Part I: $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy

    CERN Document Server

    Andreyev, Andrei

    2013-01-01

    Part I: $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy

  3. A CAVITY RING-DOWN SPECTROSCOPY MERCURY CONTINUOUS EMISSION MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Christopher C. Carter, Ph.D.

    2003-06-30

    Previous work on the detection of mercury using the cavity ring-down (CRD) technique has concentrated on the detection and characterization of the desired mercury transition. Interferent species present in flue gas emissions have been tested as well as a simulated flue gas stream. Additionally, work has been done on different mercury species such as the elemental and oxidized forms. The next phase of the effort deals with the actual sampling system. This sampling system will be responsible for acquiring a sample stream from the flue gas stack, taking it to the CRD cavity where it will be analyzed and returning the gas stream to the stack. In the process of transporting the sample gas stream every effort must be taken to minimize any losses of mercury to the walls of the sampling system as well as maintaining the mercury in its specific state (i.e. elemental, oxidized, or other mercury compounds). SRD first evaluated a number of commercially available sampling systems. These systems ranged from a complete sampling system to a number of individual components for specific tasks. SRD engineers used some commercially available components and designed a sampling system suited to the needs of the CRD instrument. This included components such as a pyrolysis oven to convert all forms of mercury to elemental mercury, a calibration air source to ensure mirror alignment and quality of the mirror surfaces, and a pumping system to maintain the CRD cavity pressure from atmospheric pressure (760 torr) down to about 50 torr. SRD also began evaluating methods for the CRD instrument to automatically find the center of a mercury transition. This procedure is necessary as the instrument must periodically measure the baseline losses of the cavity off of the mercury resonance and then return to the center of the transition to accurately measure the mercury concentration. This procedure is somewhat complicated due to the isotopic structure of the 254 nm mercury transition. As a result of

  4. Optical emission spectroscopy characterization of oxygen plasma during degradation of Escherichia coli

    International Nuclear Information System (INIS)

    Optical emission spectroscopy was applied for plasma characterization during sterilization of substrates contaminated with bacteria. The amount of 1010/ml cells of Escherichia coli was carefully applied to glass substrates and exposed to oxygen plasma glow discharge at different pressures between 30 and 200 Pa. Plasma was created in a glass discharge tube by an inductively coupled rf generator at the frequency of 27.12 MHz and output power of about 250 W. The electron temperature and plasma density were estimated with a double Langmuir probe. They were between 3 and 5 eV and 2 and 35x1015 m-3. Density of neutral oxygen atoms was measured with a catalytic probe, and was between 2 and 6x1021 m-3. Optical emission spectroscopy was performed with a low resolution spectrometer. The emission from carbon monoxide and nitrogen molecules was used to monitor the evolution of bacteria degradation. Both signals expressed a well defined maximum corresponding to peak erosion of bacteria by plasma radicals. As the sterilization was accomplished, both CO and N2 lines fell below the detection limit of the spectrometer. The bacteria degradation was also monitored by scanning electron microscope (SEM) and culturing. The SEM images corresponded well with the evolution of CO and N2 lines so the optical emission spectroscopy found a reliable tool for monitoring the sterilization process

  5. Effect of O2+, H2++ O2+, and N2++ O2+ ion-beam irradiation on the field emission properties of carbon nanotubes

    International Nuclear Information System (INIS)

    The effect of O2+, H2++ O2+, and N2++ O2+ ion-beam irradiation of carbon nanotubes (CNTs) films on the chemical and electronic properties of the material is reported. The CNTs were grown by the chemical vapor deposition technique (CVD) on silicon TiN coated substrates previously decorated with Ni particles. The Ni decoration and TiN coating were successively deposited by ion-beam assisted deposition (IBAD) and afterwards the nanotubes were grown. The whole deposition procedure was performed in situ as well as the study of the effect of ion-beam irradiation on the CNTs by x-ray photoelectron spectroscopy (XPS). Raman scattering, field-effect emission gun scanning electron microscopy (FEG-SEM), and field emission (FE) measurements were performed ex situ. The experimental data show that: (a) the presence of either H2+ or N2+ ions in the irradiation beam determines the oxygen concentration remaining in the samples as well as the studied structural characteristics; (b) due to the experimental conditions used in the study, no morphological changes have been observed after irradiation of the CNTs; (c) the FE experiments indicate that the electron emission from the CNTs follows the Fowler-Nordheim model, and it is dependent on the oxygen concentration remaining in the samples; and (d) in association with FE results, the XPS data suggest that the formation of terminal quinone groups decreases the CNTs work function of the material.

  6. Characterization of ion beam modified ceramic wear surfaces using Auger electron spectroscopy

    Science.gov (United States)

    Wei, W.; Lankford, J.

    1987-01-01

    An investigation of the surface chemistry and morphology of the wear surfaces of ceramic material surfaces modified by ion beam mixing has been conducted using Auger electron spectroscopy and secondary electron microscopy. Studies have been conducted on ceramic/ceramic friction and wear couples made up of TiC and NiMo-bonded TiC cermet pins run against Si3N4 and partially stabilized zirconia disc surfaces modified by the ion beam mixing of titanium and nickel, as well as ummodified ceramic/ceramic couples in order to determine the types of surface changes leading to the improved friction and wear behavior of the surface modified ceramics in simulated diesel environments. The results of the surface analyses indicate that the formation of a lubricating oxide layer of titanium and nickel, is responsible for the improvement in ceramic friction and wear behavior. The beneficial effect of this oxide layer depends on several factors, including the adherence of the surface modified layer or subsequently formed oxide layer to the disc substrate, the substrate materials, the conditions of ion beam mixing, and the environmental conditions.

  7. Optical Emission Spectroscopy of Low-Discharge-Power Magnetron Sputtering Plasmas Using Pure Tungsten Target

    Science.gov (United States)

    Matsunaga, Takeaki; Ohshima, Tamiko; Kawasaki, Hiroharu; Kaneko, Tatsuya; Yagyu, Yoshihito; Suda, Yoshiaki

    2010-08-01

    To study the mechanism of a tungsten oxide (WO3) thin film using an RF magnetron sputtering method, optical emission spectroscopic (OES) measurements for the RF plasma of a pure W target have been performed. We also examined the crystalline structure and atomic composition rate of the prepared thin film using X-ray photoelectron spectroscopy (XPS). Experimental results indicate that Ar I emission peak intensity slightly increased with increasing Ar gas mixture. On the other hand, W I emission peak intensity rapidly increased with increasing Ar gas mixture. The increase rates of these two emission peak intensities are different, which may be due to the difference in emission mechanism. O I emission peak intensity decreased with increasing Ar gas mixture, indicating that O I emission intensity increased with increasing O2 gas mixture. Electron density and deposition rate increased with increasing Ar gas mixture, and their dependences on Ar gas mixture were very similar to that of Ar I emission. XPS analyses indicate that the oxidation ratio of the prepared film was slightly decreased with decreasing Ar gas mixture. These results suggest that the W sources of the WO3 film on the substrate are W atoms and WOx molecules sputtered from the W target. The plasma phase reaction between W and O atoms and the intermediate-energy O atomic and/or O2 molecular reaction on the surface of the substrate are considered to be important for WO3 film production in low-energy magnetron sputtering deposition.

  8. Soil humic-like organic compounds in prescribed fire emissions using nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Here we present the chemical characterization of the water-soluble organic carbon fraction of atmospheric aerosol collected during a prescribed fire burn in relation to soil organic matter and biomass combustion. Using nuclear magnetic resonance spectroscopy, we observed that humic-like substances in fire emissions have been associated with soil organic matter rather than biomass. Using a chemical mass balance model, we estimated that soil organic matter may contribute up to 41% of organic hydrogen and up to 27% of water-soluble organic carbon in fire emissions. Dust particles, when mixed with fresh combustion emissions, substantially enhances the atmospheric oxidative capacity, particle formation and microphysical properties of clouds influencing the climatic responses of atmospheric aeroso. Owing to the large emissions of combustion aerosol during fires, the release of dust particles from soil surfaces that are subjected to intense heating and shear stress has, so far, been lacking. -- Highlights: •We characterized the water-soluble organic carbon (WSOC) of fire emissions by NMR. •Distinct patterns were observed for soil dust and vegetation combustion emissions. •Soil organic matter accounted for most of WSOC in early prescribed burn emissions. -- Humic-like soil organic matter may be an important component of particulate emissions in the early stages of wildfires

  9. Universal Slow RI-Beam Facility at RIKEN RIBF for Laser Spectroscopy of Short-Lived Nuclei

    International Nuclear Information System (INIS)

    A universal slow RI-beam facility (SLOWRI) for precision atomic spectroscopy is being built at the RIKEN RI-beam factory. The facility will provide a wide variety of low-energy nuclear ions of all elements produced by projectile fragmentation of high-energy heavy-ion beams and thermalized by an RF-carpet ion guide. At prototype SLOWRI, radioactive Be isotope ions produced at 1 GeV were decelerated and cooled in an ion trap down to 1 μeV by employing laser cooling. The ground state hyperfine structures of 7Be+ and 11Be+ were measured accurately by laser microwave double resonance spectroscopy. Measurements of the S1/2→P1/2, P3/2 transition frequencies of 7,9,10,11Be+ ions are also in progress aiming at the study of the nuclear charge radii. Other possible experiment at SLOWRI, such as mass spectroscopy, are also discussed.

  10. Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose

    International Nuclear Information System (INIS)

    Recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. There is a correlation between the captured light and expected dose under certain conditions, yet discrepancies have also been observed and a complete examination of the theoretical differences has not been done. In this study, a fundamental comparison between the Cherenkov emission and absorbed dose was explored for x-ray photons, electrons, and protons using both a theoretical and Monte Carlo-based analysis. Based on the findings of where dose correlates with Cherenkov emission, it was concluded that for x-ray photons the light emission would be optimally suited for narrow beam stereotactic radiation therapy and surgery validation studies, for verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near monoenergetic sources (e.g., Co-60 and brachy therapy sources) and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although post-irradiation detection of light emission from radioisotopes could prove to be useful. (paper)

  11. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  12. Hole emission from Ge/Si quantum dots studied by time-resolved capacitance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kapteyn, C.M.A.; Lion, M.; Heitz, R.; Bimberg, D. [Technische Univ. Berlin (Germany). Inst. fuer Festkoerperphysik; Miesner, C.; Asperger, T.; Brunner, K.; Abstreiter, G. [Technische Univ. Muenchen, Garching (Germany). Walter-Schottky-Inst. fuer Physikalische Grundlagen der Halbleiterelektronik

    2001-03-01

    Emission of holes from self-organized Ge quantum dots (QDs) embedded in Si Schottky diodes is studied by time-resolved capacitance spectroscopy (DLTS). The DLTS signal is rather broad and depends strongly on the filling and detection bias conditions. The observed dependence is interpreted in terms of carrier emission from many-hole states of the QDs. The activation energies obtained from the DLTS measurements are a function of the amount of stored charge and the position of the Fermi level in the QDs. (orig.)

  13. Characterization of coal oil using three-dimensional excitation and emission matrix fluorescence spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Xue Xiao; Yujun Zhang; Zhigang Wang; Dan Jin; Gaofang Yin; Wenqing Liu

    2009-01-01

    Three-dimensioned (3D) excitation-emission matrix (EEM) fluorescence spectroscopy is applied to charac terize the coal oil. The results show that the 3D fluorescence spectra of coal oil in aqueous solution mainly have one broad peak. This peak is identified at the excitation/emission wavelengths of 270/290 nm. The relation between the fluorescence intensity and the concentration of coal oil is also studied. When the concentration lies between 2 鈥? 2000 ppm, the relation between the fluorescence intensity and the concen tration of coal oil is well linear. The nature of solvents significantly affects the EEM fluorescence of coal oil.

  14. Determination of heavy metals in solid emission and immission samples using atomic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fara, M.; Novak, F. [EGU Prague, PLC, Bichovice, Prague (Czechoslovakia)

    1995-12-01

    Both flame and electrothermal methods of atomic absorption spectroscopy (AAS) have been applied to the determination of Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, TI, Se, V and Zn in emission and emission (deposition) samples decomposed in open PTFE test-tubes by individual fuming-off hydrofluoric, perchloroic and nitric acid. An alternative hydride technique was also used for As and Se determination and Hg was determined using a self-contained AAS analyzer. A graphite platform proved good to overcome non-spectral interferences in AAS-ETA. Methods developed were verified by reference materials (inc. NBS 1633a).

  15. Proton beam micromachining: electron emission from SU-8 resist during ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A. E-mail: phybaa@nus.edu.sg; Rajta, I.; Teo, E.J.; Kan, J.A. van; Watt, F

    2002-05-01

    Proton beam micromachining (PBM) is a direct write lithographic technique that uses a focused beam of MeV protons to pattern a resist material. The most common resist material used in the PBM process is SU-8 which is usually spin coated onto various substrates. The method used to ensure that the correct dose is delivered to the sample during irradiation is Rutherford backscattering spectrometry (RBS). There are however limitations to using the RBS signal for normalizing the dose in highly sensitive resist materials such as SU-8. The limited number of backscatter events means that normalizing the dose for every pixel is not possible. The secondary electron yield for SU-8 is at least an order of magnitude higher than that for backscattered ions. With an appropriate detector these signals can be essentially used for ion detection and thus used to accurately monitor ion dose. In this paper we investigate the secondary electron yield from SU-8 polymer resist layers of varying thickness on silicon. It is shown that the signals produced during MeV ion irradiation can be directly related to the ion dose and used for dose normalization during PBM.

  16. Spatially resolved spectroscopy of emission-line gas in QSO Host galaxies

    CERN Document Server

    Sheinis, A I

    2001-01-01

    We present off-nuclear spectra of 3 radio loud QSO's, 3C249.1, 3C273 and 3C323.1., taken with the echellette spectrograph and imager (ESI) at Keck observatory. From these spectra we have extracted the spatial profile along the slit of the [OIII], $\\lambda= \\textsf{5007}$ line. Fitted Gaussian distributions to each of these profiles show emission-line gas out to several tens of kiloparsecs from the galaxy nucleus. Most observations show several gas components at distinct velocities and velocity dispersions, much of which is above the escape velocity for any resonable mass galaxy. In addition, we show slitless spectroscopy images for one other object, 3C48. From the slitless spectroscopy images we can extract 2-dimensional spatial as well as velocity information on the emission line gas.

  17. Characterization of Ar/Cu electron-cyclotron-resonance plasmas using optical emission spectroscopy

    International Nuclear Information System (INIS)

    Optical emission spectroscopy is used to investigate trends with changes in processing parameters for Ar/Cu plasmas in an electron-cyclotron-resonance (ECR) plasma deposition system. The primary motivation for this work is to monitor trends in ionization fractions for copper deposition plasmas using a noninterfering diagnostic tool. The system, which consists of a solid copper sputter target coupled to a permanent magnet ECR microwave plasma system, is operated in the range of 1 endash 6 mTorr argon with net microwave input power of 500 endash 1500 W. Emission from the following excited states is monitored: Ar neutrals (696.5 nm); Ar ions (488 nm); Cu neutrals (521.8 and 216.5 nm); and Cu ions (213.6 nm). Cu ion emission and Cu neutral emission monotonically increase with net microwave input power but at slightly different rates for different pressures, while argon-ion emission as a function of pressure shows a broad peak around 4 mTorr. The ratio of Cu ion emission to Cu neutral emission is used as an indicator of the relative ionization efficiency for Cu and peaks near 5 mTorr. Spectroscopic estimates of electron temperature differences between pure Ar and Ar/Cu plasmas are also presented

  18. Potential application of flame infrared emission spectroscopy (FIRE) in on-line analyzers

    International Nuclear Information System (INIS)

    This paper discusses an investigation into the infrared emission from organic compounds undergoing combustion in hydrogen/air flames. Flame infrared emission (FIRE) spectroscopy has been applied to measurement such as: total purgeable organic carbon, total inorganic carbon, chloride, and available chlorine in water samples. Additionally, FIRE technology has been applied as a detector for gas chromatography. Infrared emission bands form vibrationally excited hydrogen chloride, hydrogen fluoride, and carbon dioxide are identified. Detection of one or more of these emission bands allowed the selective determination of organic compounds containing carbon, chlorine, or fluorine as they elute from a gas chromatography column. In addition to infrared emission from carbon dioxide, wavelengths characteristic of hydrogen fluoride, hydrogen chloride, and sulfur dioxide have been identified. Combustion of chlorine containing compounds in a hydrogen rich (reducing) flame will produce vibrationally excited hydrogen chloride. Relaxation of hydrogen chloride from excited state to the ground state results in emission of infrared radiation at 3.8 micron. This emission is conveniently located between the mission bands for water (2.6 - 3.6 micron) and carbon dioxide (4.4 microns)

  19. GROUND-BASED NEAR-INFRARED EMISSION SPECTROSCOPY OF HD 189733B

    Energy Technology Data Exchange (ETDEWEB)

    Waldmann, I. P.; Tinetti, G. [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT (United Kingdom); Drossart, P. [LESIA, Observatoire de Paris, CNRS, Universit Pierre et Marie Curie, Universit Paris-Diderot. 5 place Jules Janssen, 92195 Meudon (France); Swain, M. R.; Deroo, P. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Griffith, C. A., E-mail: ingo@star.ucl.ac.uk [Department of Planetary Sciences, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721 (United States)

    2012-01-01

    We investigate the K- and L-band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA Infrared Telescope Facility. The observations for each of these three nights use equivalent instrument settings and the data from one of the nights have previously been reported by Swain et al. We describe an improved data analysis method that, in conjunction with the multi-night data set, allows increased spectral resolution (R {approx} 175) leading to high-confidence identification of spectral features. We confirm the previously reported strong emission at {approx}3.3 {mu}m and, by assuming a 5% vibrational temperature excess for methane, we show that non-LTE emission from the methane {nu}{sub 3} branch is a physically plausible source of this emission. We consider two possible energy sources that could power non-LTE emission and additional modeling is needed to obtain a detailed understanding of the physics of the emission mechanism. The validity of the data analysis method and the presence of strong 3.3 {mu}m emission are independently confirmed by simultaneous, long-slit, L-band spectroscopy of HD 189733b and a comparison star.

  20. GROUND-BASED NEAR-INFRARED EMISSION SPECTROSCOPY OF HD 189733B

    International Nuclear Information System (INIS)

    We investigate the K- and L-band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA Infrared Telescope Facility. The observations for each of these three nights use equivalent instrument settings and the data from one of the nights have previously been reported by Swain et al. We describe an improved data analysis method that, in conjunction with the multi-night data set, allows increased spectral resolution (R ∼ 175) leading to high-confidence identification of spectral features. We confirm the previously reported strong emission at ∼3.3 μm and, by assuming a 5% vibrational temperature excess for methane, we show that non-LTE emission from the methane ν3 branch is a physically plausible source of this emission. We consider two possible energy sources that could power non-LTE emission and additional modeling is needed to obtain a detailed understanding of the physics of the emission mechanism. The validity of the data analysis method and the presence of strong 3.3 μm emission are independently confirmed by simultaneous, long-slit, L-band spectroscopy of HD 189733b and a comparison star.

  1. Copper Determination in Gunshot Residue by Cyclic Voltammetric and Inductive Coupled Plasma-Optical Emission Spectroscopy

    OpenAIRE

    Mohd Hashim Nurul’Afiqah Hashimah; Mohd Zain Zainiharyati; Jaafar Mohd Zuli

    2016-01-01

    Analysis of gunshot residue (GSR) is a crucial evidences for a forensic analyst in the fastest way. GSR analysis insists a suitable method provides a relatively simple, rapid and precise information on the spot at the crime scene. Therefore, the analysis of Cu(II) in GSR using cyclic voltammetry (CV) on screen printed carbon electrode (SPCE) is a better choice compared to previous alternative methods such as Inductive Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) those required a lon...

  2. PECVD Chamber Cleaning End Point Detection (EPD) Using Optical Emission Spectroscopy Data

    OpenAIRE

    Sang Jeen Hong; Ho Jae Lee; Dongsun Seo; Gary S. May

    2013-01-01

    In-situ optical emission spectroscopy (OES) is employed for PECVD chamber monitoring. OES is used as an addonsensor to monitoring and cleaning end point detection (EPD). On monitoring plasma chemistry using OES, theprocess gas and by-product gas are simultaneously monitored. Principal component analysis (PCA) enhances thecapability of end point detection using OES data. Through chamber cleaning monitoring using OES, cleaning time isreduced by 53%, in general. Therefore, the gas usage of fluor...

  3. Experimental investigations of field emission method for high-charge ion beams generation

    International Nuclear Information System (INIS)

    Some experiments for ion beams generation were fulfilled in case of feeding the pulse voltage of +300 - 400 kV 50 ns to a block of aluminum knife-edge emitters. The measurements performed with using of track detectors, time-of- flight mass spectrometer, and magnetic spectrometer were shown that the ion beams largely consist of highcharge aluminum ions (Z = 8±1) and currents 30-200 A; generation of high-charge ions is connected with the field emission of the ions out of the emitters at the considerable electric field strength (E ∼ 109 V/cm).

  4. Amplified spontaneous emission of a molecular nitrogen laser excited by an intense relativistic electron beam

    International Nuclear Information System (INIS)

    Report of a study of the shape and length of the output pulse of a molecular nitrogen laser, excited by an intense relativistic electron beam, is described. The rate equations are computer solved, at first ignoring the spontaneous emission during the excitation process. Afterwards the rate equations are solved taking into account excitation functions of various shapes and lengths, related to electron-beam pulses of a few kA and a few nsec. Laser power output, energy, and peak-time, i.e., the time at which the gain reaches its saturated value, are given and discussed as functions of the intensity and rise time of the excitation functions

  5. First hydrogen operation of NIO1: Characterization of the source plasma by means of an optical emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Barbisan, M., E-mail: marco.barbisan@igi.cnr.it; Baltador, C.; Zaniol, B.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Univ. of Padua, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, v.le dell’Università 2, I-35020 Legnaro (Italy); Fantz, U.; Wünderlich, D. [Max-Planck Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Vialetto, L. [Università degli Studi di Padova, Via 8 Febbraio, 2, 35122 Padova (Italy)

    2016-02-15

    NIO1 (Negative Ion Optimization 1) is a compact and flexible radio frequency H{sup −} ion source, developed by Consorzio RFX and INFN-LNL. The aim of the experimentation on NIO1 is the optimization of both the production of negative ions and their extraction and beam optics. In the initial phase of its commissioning, NIO1 was operated with nitrogen, but now the source is regularly operated also with hydrogen. To evaluate the source performances, an optical emission spectroscopy diagnostic was installed. The system includes a low resolution spectrometer in the spectral range of 300-850 nm and a high resolution (50 pm) one, to study, respectively, the atomic and the molecular emissions in the visible range. The spectroscopic data have been interpreted also by means of a collisional-radiative model developed at IPP Garching. Besides the diagnostic hardware and the data analysis methods, the paper presents the first plasma measurements across a transition to the full H mode, in a hydrogen discharge. The characteristic signatures of this transition in the plasma parameters are described, in particular, the sudden increase of the light emitted from the plasma above a certain power threshold.

  6. Simulation study of the field emission and photoemission on metallic photocathodes. Emitted beam dynamics

    International Nuclear Information System (INIS)

    After a bibliographic research on field emission, photoemission and photo-field emission, the principle of the field equations (Poisson and Maxwell's) resolution by the finite element method is developed. The PRIAM program is shown to be efficient (adaptive mesh and refinement in the selected area). Several possibilities exist to reduce the effect of space charge such as the decrease of the laser pulse duration, the increase of the electric field and the application of a magnetic field. Calculations of the transverse emittance for a metallic plan photocathode have been made at different moments of the emission: transverse emittance is small at the beginning and at the end of the emission. It passes by a maximum which can be the origin of the electronic beam explosion for strong field. If a small emittance is wanted, one must illuminate the photocathode by a short pulsed laser

  7. Low-energy electro- and photo-emission spectroscopy of GaN materials and devices

    International Nuclear Information System (INIS)

    In hot-electron semiconductor devices, carrier transport extends over a wide range of conduction states, which often includes multiple satellite valleys. Electrical measurements can hardly give access to the transport processes over such a wide range without resorting to models and simulations. An alternative experimental approach however exists which is based on low-energy electron spectroscopy and provides, in a number of cases, very direct and selective information on hot-electron transport mechanisms. Recent results obtained in GaN crystals and devices by electron emission spectroscopy are discussed. Using near-band-gap photoemission, the energy position of the first satellite valley in wurtzite GaN is directly determined. By electro-emission spectroscopy, we show that the measurement of the electron spectrum emitted from a GaN p-n junction and InGaN/GaN light-emitting diodes (LEDs) under electrical injection of carriers provides a direct observation of transport processes in these devices. In particular, at high injected current density, high-energy features appear in the electro-emission spectrum of the LEDs showing that Auger electrons are being generated in the active region. These measurements allow us identifying the microscopic mechanism responsible for droop which represents a major hurdle for widespread adoption of solid-state lighting

  8. A trap-based pulsed positron beam optimised for positronium laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B. S., E-mail: ben.cooper.13@ucl.ac.uk; Alonso, A. M.; Deller, A.; Wall, T. E.; Cassidy, D. B. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-10-15

    We describe a pulsed positron beam that is optimised for positronium (Ps) laser-spectroscopy experiments. The system is based on a two-stage Surko-type buffer gas trap that produces 4 ns wide pulses containing up to 5 × 10{sup 5} positrons at a rate of 0.5-10 Hz. By implanting positrons from the trap into a suitable target material, a dilute positronium gas with an initial density of the order of 10{sup 7} cm{sup −3} is created in vacuum. This is then probed with pulsed (ns) laser systems, where various Ps-laser interactions have been observed via changes in Ps annihilation rates using a fast gamma ray detector. We demonstrate the capabilities of the apparatus and detection methodology via the observation of Rydberg positronium atoms with principal quantum numbers ranging from 11 to 22 and the Stark broadening of the n = 2 → 11 transition in electric fields.

  9. In-beam γ-ray spectroscopy of 38,40,42Si

    International Nuclear Information System (INIS)

    Excited states in the nuclei 38,40,42Si have been studied using in-beam γ-ray spectroscopy following multi-nucleon removal reactions to investigate the systematics of excitation energies along the Z=14 isotopic chain. The most probable candidates for the transition from the yrast 4+ state were tentatively assigned among several γ lines newly observed in the present study. The energy ratios between the 21+ and 41+ states were obtained to be 2.09(5), 2.56(5) and 2.93(5) for 38,40,42Si, respectively, indicating a rapid development of deformation in Si isotopes from N=24 to, at least, N=28. (authors)

  10. Proton beam characterization by proton-induced acoustic emission: simulation studies

    International Nuclear Information System (INIS)

    Due to their Bragg peak, proton beams are capable of delivering a targeted dose of radiation to a narrow volume, but range uncertainties currently limit their accuracy. One promising beam characterization technique, protoacoustic range verification, measures the acoustic emission generated by the proton beam. We simulated the pressure waves generated by proton radiation passing through water. We observed that the proton-induced acoustic signal consists of two peaks, labeled α and γ, with two originating sources. The α acoustic peak is generated by the pre-Bragg peak heated region whereas the source of the γ acoustic peak is the proton Bragg peak. The arrival time of the α and γ peaks at a transducer reveals the distance from the beam propagation axis and Bragg peak center, respectively. The maximum pressure is not observed directly above the Bragg peak due to interference of the acoustic signals. Range verification based on the arrival times is shown to be more effective than determining the Bragg peak position based on pressure amplitudes. The temporal width of the α and γ peaks are linearly proportional to the beam diameter and Bragg peak width, respectively. The temporal separation between compression and rarefaction peaks is proportional to the spill time width. The pressure wave expected from a spread out Bragg peak dose is characterized. The simulations also show that acoustic monitoring can verify the proton beam dose distribution and range by characterizing the Bragg peak position to within ∼1 mm. (paper)

  11. Charge exchange produced K-shell x-ray emission from Ar16+ in a tokamak plasma with neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P; Bitter, M; Marion, M; Olson, R E

    2004-12-27

    High-resolution spectroscopy of hot tokamak plasma seeded with argon ions and interacting with an energetic, short-pulse neutral hydrogen beam was used to obtain the first high-resolution K-shell x-ray spectrum formed solely by charge exchange. The observed K-shell emission of Ar{sup 16+} is dominated by the intercombination and forbidden lines, providing clear signatures of charge exchange. Results from an ab initio atomic cascade model provide excellent agreement, validating a semiclassical approach for calculating charge exchange cross sections.

  12. [Study of Surface Enhanced Raman Spectroscopy on Copper Films Modified by Ion Beam].

    Science.gov (United States)

    Ding, Liang-liang; Hong, Rui-jin; Tao, Chun-xian; Zhang, Da-wei

    2015-11-01

    Surface-enhanced Raman Spectroscopy (SERS) was a rapid non-destructive testing. It was based on detecting molecule vibrational spectrum which was adsorbed on the metallic surface. Now it was widely used in surface adsorption, electrochemical catalysis, sensors, bio-medical testing, trace amount analysis and other fields. In our experiment, copper metallic films were deposited 50 nm on BK7 glass substrates by direct current magnetron sputtering. And then the films were employed for the Ar ion beam etching modification. The structure, morphology and optical properties was characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM), spectrophotometer and Raman spectroscopy. In the XRD graph, the peak value of modify copper film were the same with the untreated film. So the structure of copper film was not change. With increasing the power of Ar ion, the surface roughness was changed, and scattered spectrum intensity was increased by surface roughness added. With Rhodamine B (Rh B) as a probe molecule, Raman scattered spectrum was detected on modify copper film. Compared with the different samples, we can find the Raman signal was enhanced by surface roughness added. It will have some value on study the principles of SERS. PMID:26978913

  13. Electrochemical impedance spectroscopy on nanostructured carbon electrodes grown by supersonic cluster beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Luca Giacomo; Bardizza, Giorgio; Podesta, Alessandro; Milani, Paolo; Piseri, Paolo, E-mail: piseri@mi.infn.it [Universita degli Studi di Milano, Dipartimento di Fisica and CIMaINa (Italy)

    2013-02-15

    Nanostructured porous films of carbon with density of about 0.5 g/cm{sup 3} and 200 nm thickness were deposited at room temperature by supersonic cluster beam deposition (SCBD) from carbon clusters formed in the gas phase. Carbon film surface topography, determined by atomic force microscopy, reveals a surface roughness of 16 nm and a granular morphology arising from the low kinetic energy ballistic deposition regime. The material is characterized by a highly disordered carbon structure with predominant sp2 hybridization as evidenced by Raman spectroscopy. The interface properties of nanostructured carbon electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy employing KOH 1 M solution as aqueous electrolyte. An increase of the double layer capacitance is observed when the electrodes are heat treated in air or when a nanostructured nickel layer deposited by SCBD on top of a sputter deposited film of the same metal is employed as a current collector instead of a plain metallic film. This enhancement is consistent with an improved charge injection in the active material and is ascribed to the modification of the electrical contact at the interface between the carbon and the metal current collector. Specific capacitance values up to 120 F/g have been measured for the electrodes with nanostructured metal/carbon interface.

  14. Positron spectroscopy of 2D materials using an advanced high intensity positron beam

    Science.gov (United States)

    McDonald, A.; Chirayath, V.; Lim, Z.; Gladen, R.; Chrysler, M.; Fairchild, A.; Koymen, A.; Weiss, A.

    An advanced high intensity variable energy positron beam(~1eV to 20keV) has been designed, tested and utilized for the first coincidence Doppler broadening (CDB) measurements on 6-8 layers graphene on polycrystalline Cu sample. The system is capable of simultaneous Positron annihilation induced Auger electron Spectroscopy (PAES) and CDB measurements giving it unparalleled sensitivity to chemical structure at external surfaces, interfaces and internal pore surfaces. The system has a 3m flight path up to a micro channel plate (MCP) for the Auger electrons emitted from the sample. This gives a superior energy resolution for PAES. A solid rare gas(Neon) moderator was used for the generation of the monoenergetic positron beam. The positrons were successfully transported to the sample chamber using axial magnetic field generated with a series of Helmholtz coils. We will discuss the PAES and coincidence Doppler broadening measurements on graphene -Cu sample and present an analysis of the gamma spectra which indicates that a fraction of the positrons implanted at energies 7-60eV can become trapped at the graphene/metal interface. This work was supported by NSF Grant No. DMR 1508719 and DMR 1338130.

  15. Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water

    International Nuclear Information System (INIS)

    We developed a method for two-dimensional space-resolved emission spectroscopy of laser-induced plasma in water to investigate the spatial distribution of atomic species involved in the plasma. Using this method, the laser ablation plasma produced on a Cu target in 5 mM NaCl aqueous solution was examined. The emission spectrum varied considerably depending on the detecting position. The temperature and the atomic density ratio NNa/NCu at various detecting positions were evaluated by fitting emission spectra to a theoretical model based on the Boltzmann distribution. We are successful in observing even a small difference between the distributions of the plasma parameters along the directions vertical and horizontal to the surface. The present approach gives direct information for sound understanding of the behavior of laser ablation plasma produced on a solid surface in water.

  16. Plasma optical emission spectroscopy diagnostic during amorphous silicon thin films deposition by Rf sputtering technique

    International Nuclear Information System (INIS)

    This paper deals with the study of the glow discharge, used for amorphous silicon thin films deposition by Rf sputtering technique. The produced plasma is investigated by mean of the optical emission spectroscopy (OES) analysis. Different plasmas obtained with changing the gas pressure and Rf powers were analysed at different positions in the inter-electrode space. Emission lines from Ar, Si, Si+ and Ar+ were observed in the visible region. It was found that emission intensities of all the observed lines have a spatial Gaussian shape. The maximum intensity is located in the core of the plasma and decrease in the electrodes region. The ratio between the Si and Ar+ intensities (ISi/IAr+), in the target region, is proposed as a new tool to estimate the Ar sputtering yield. This ratio was compared to the theoretical calculated sputtering yield. The difference between these two quantities is exploited to determine the contribution of fast Ar neutrals in the sputtering process.

  17. Mid-infrared Molecular Emission Studies from Energetic Materials using Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Brown, Ei; Hommerich, Uwe; Yang, Clayton; Trivedi, Sudhir; Samuels, Alan; Snyder, Peter

    2011-10-01

    Laser-induced breakdown spectroscopy (LIBS) is a powerful diagnostic tool for detection of trace elements by monitoring the atomic and ionic emission from laser-induced plasmas. The laser-induced plasma was produced by focusing a 30 mJ pulsed Nd:YAG laser (1064 nm) to dissociate, atomize, and ionize target molecules. In this work, LIBS emissions in the mid-infrared (MIR) region were studied for potential applications in chemical, biological, and explosives (CBE) sensing. We report on the observation of MIR emissions from energetic materials (e.g. ammonium compounds) due to laser-induced breakdown processes. All samples showed LIBS-triggered oxygenated breakdown products as well as partially dissociated and recombination molecular species. More detailed results of the performed MIR LIBS studies on the energetic materials will be discussed at the conference.

  18. Nuclear structure of light thallium isotopes as deduced from laser spectroscopy on a fast atom beam

    International Nuclear Information System (INIS)

    After optimizing the system by experiments on /sup 201,203,205/Tl, the neutron-deficient isotopes 189-193Tl have been studied using the collinear fast atom beam laser spectroscopy system at UNISOR on-line to the Holifield Heavy Ion Research Facility. A sensitive system for the measurements was developed since the light isotopes were available in mass-separated beams of only 7 x 104 to 4 x 105 atoms per second. By laser excitation of the 535 nm atomic transitions of atoms in the beam, the 6s27s 2S/sub 1/2/ and 6s26s 2P/sub 3/2/ hyperfine structures were measured, as were the isotope shifts of the 535 nm transitions. From these, the magnetic dipole moments, spectroscopic quadrupole moments and isotopic changes in mean-square charge radius were deduced. The magnetic dipole moments are consistent with previous data. The /sup 190,192/Tl isotopes show a considerable difference in quadrupole deformations as well as an anomalous isotope shift with respect to 194Tl. A large isomer shift in 193Tl is observed implying a larger deformation in the 9/2- isomer than in the 1/2+ ground state. The /sup 189,191,193/Tl isomers show increasing deformation away from stability. A deformed shell model calculation indicates that this increase in deformation can account for the dropping of the 9/2- band in these isotopes while an increase in neutron pairing correlations, having opposite and compensating effects on the rotational moment of inertia, maintains the 9/2- strong-coupled band structure. 105 refs., 27 figs

  19. Eye-safe infrared laser-induced breakdown spectroscopy (LIBS) emissions from energetic materials

    Science.gov (United States)

    Brown, Ei E.; Hömmerich, Uwe; Yang, Clayton C.; Jin, Feng; Trivedi, Sudhir B.; Samuels, Alan C.

    2016-05-01

    Laser-induced breakdown spectroscopy is a powerful diagnostic tool for detection of trace elements by monitoring the atomic and ionic emission from laser-induced plasmas. Besides elemental emissions from conventional UV-Vis LIBS, molecular LIBS emission signatures of the target compounds were observed in the long-wave infrared (LWIR) region in recent studies. Most current LIBS studies employ the fundamental Nd:YAG laser output at 1.064 μm, which has extremely low eye-damage threshold. In this work, comparative LWIR-LIBS emissions studies using traditional 1.064 μm pumping and eye-safe laser wavelength at 1.574 μm were performed on several energetic materials for applications in chemical, biological, and explosive (CBE) sensing. A Q-switched Nd: YAG laser operating at 1.064 μm and the 1.574 μm output of a pulsed Nd:YAG pumped Optical Parametric Oscillator were employed as the excitation sources. The investigated energetic materials were studied for the appearance of LWIR-LIBS emissions (4-12 μm) that are directly indicative of oxygenated breakdown products as well as partially dissociated and recombination molecular species. The observed molecular IR LIBS emission bands showed strong correlation with FTIR absorption spectra of the studied materials for 1.064 μm and 1.574 μm pump wavelengths.

  20. Modeling of explosive electron emission and electron beam dynamics in high-current devices

    International Nuclear Information System (INIS)

    Based on a detailed analysis of explosive electron emission in high-current electronic devices, we formulate a system of equations that describes the expansion of the cathode plasma and the generation of high-current electron beams. The system underlies the numerical algorithm for the hybrid code which enables simulating the charged particles' dynamics in high-current vircators with open resonators. Using the Gabor-Morlet transform, we perform the time-frequency analysis of vircator radiation

  1. Modeling of explosive electron emission and electron beam dynamics in high-current devices

    Science.gov (United States)

    Anishchenko, S. V.; Gurinovich, A. A.

    2014-03-01

    Based on a detailed analysis of explosive electron emission in high-current electronic devices, we formulate a system of equations that describes the expansion of the cathode plasma and the generation of high-current electron beams. The system underlies the numerical algorithm for the hybrid code which enables simulating the charged particles' dynamics in high-current vircators with open resonators. Using the Gabor-Morlet transform, we perform the time-frequency analysis of vircator radiation.

  2. Theoretical research on electron beam modulation in a field-emission cold cathode electron gun

    International Nuclear Information System (INIS)

    In order to develop miniaturized and integrated electron vacuum devices, the electron beam modulation in a field-emission (FE) electron gun based on carbon nanotubes is researched. By feeding a high-frequency field between the cathode and the anode, the steady FE electron beam can be modulated in the electron gun. The optimal structure of the electron gun is discovered using 3D electromagnetism simulation software, and the FE electron gun is simulated by PIC simulation software. The results show that a broadband (74–114 GHz) modulation can be achieved by the electron gun with a rhombus channel, and the modulation amplitude of the beam current increases with the increases in the input power and the electrostatic field

  3. Beam profile measurement of ES-200 using secondary electron emission monitor

    Directory of Open Access Journals (Sweden)

    E Ebrahimi Basabi

    2015-09-01

    Full Text Available Up to now, different designs have been introduced for measurement beam profile accelerators. Secondary electron emission monitors (SEM are one of these devices which have been used for this purpose. In this work, a SEM has been constructed to measure beam profile of ES-200 accelerator, a proton electrostatic accelerator which is installed at SBU. Profile grid for both planes designed with 16 wires which are insulated relative to each other. The particles with maximum energy of 200 keV and maximum current of 400 μA are stopped in copper wires. Each of the wires has an individual current-to-voltage amplifier. With a multiplexer, the analogue values are transported to an ADC. The ADCs are read out by a microcontroller and finally profile of beam shows by a user interface program

  4. Experimental validation of ultra-thin metalenses for N-beam emissions based on transformation optics

    International Nuclear Information System (INIS)

    A general design of metalenses for N-beam emissions is proposed based on transformation optics. A linear mapping function is adopted to achieve the homogeneous characterization of the transforming medium, which is therefore easy to be achieved compared with previous designs limited by inhomogeneity based on transformation optics. To verify the theoretical design, a four-beam antenna constructed with ultrathin, homogenous, and uniaxial anisotropic metalens is designed, fabricated, and measured. It is shown that the realized gain of the four-beam antenna is increased by 6 dB compared with the single dipole source, while working frequency and relative bandwidth are kept unchanged. The measured far-field pattern verifies theoretical design procedure

  5. Secondary emission monitor for keV ion and antiproton beams

    CERN Document Server

    Sosa, Alejandro; Bravin, Enrico; Harasimowciz, Janusz; Welsch, C P

    2013-01-01

    Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Sec- ondary electron Emission Monitor (SEM) has been de- signed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.

  6. Experimental validation of ultra-thin metalenses for N-beam emissions based on transformation optics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kuang, E-mail: zhangkuang@hit.edu.cn [Department of Microwave Engineering, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Millimeter Waves, Nanjing 210096 (China); Ding, Xumin; Meng, Fanrong; Wu, Qun [Department of Microwave Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wo, Deliang [Shang Hai Electro-Mechanical Engineering Institute, Shanghai 201109 (China)

    2016-02-01

    A general design of metalenses for N-beam emissions is proposed based on transformation optics. A linear mapping function is adopted to achieve the homogeneous characterization of the transforming medium, which is therefore easy to be achieved compared with previous designs limited by inhomogeneity based on transformation optics. To verify the theoretical design, a four-beam antenna constructed with ultrathin, homogenous, and uniaxial anisotropic metalens is designed, fabricated, and measured. It is shown that the realized gain of the four-beam antenna is increased by 6 dB compared with the single dipole source, while working frequency and relative bandwidth are kept unchanged. The measured far-field pattern verifies theoretical design procedure.

  7. Corona discharge radical emission spectroscopy: a multi-channel detector with nose-type function for discrimination analysis.

    Science.gov (United States)

    Tian, Yunfei; Wu, Peng; Wu, Xi; Jiang, Xiaoming; Xu, Kailai; Hou, Xiandeng

    2013-04-21

    A simple and economical multi-channel optical sensor using corona discharge radical emission spectroscopy is developed and explored as an optical nose for discrimination analysis of volatile organic compounds, wines, and even isomers. PMID:23471437

  8. X-ray laser spectroscopy with an electron beam ion trap at the free electron laser LCLS

    International Nuclear Information System (INIS)

    We present a first laser spectroscopy experiment in the keV energy regime, performed at the Free-Electron Laser LCLS at Stanford. An electron beam ion trap was used to provide a target of highly charged O, F and Fe ions. The resonant fluorescence spectra obtained for various transitions were calibrated to simultaneously measured Lyman lines of hydrogenic ions.

  9. Spectroscopy of neutron-rich hypernucleus, $^{7}_{\\Lambda}$He by electron beam

    CERN Document Server

    Gogami, T; Kawama, D; Achenbach, P; Ahmidouch, A; Albayrak, I; Androic, D; Asaturyan, A; Asaturyan, R; Ates, O; Baturin, P; Badui, R; Boeglin, W; Bono, J; Brash, E; Carter, P; Chiba, A; Christy, E; Danagoulian, S; De Leo, R; Doi, D; Elaasar, M; Ent, R; Fujii, Y; Fujita, M; Furic, M; Gabrielyan, M; Gan, L; Garibaldi, F; Gaskell, D; Gasparian, A; Han, Y; Hashimoto, O; Horn, T; Hu, B; Hungerford, Ed V; Jones, M; Kanda, H; Kaneta, M; Kato, S; Kawai, M; Khanal, H; Kohl, M; Liyanage, A; Luo, W; Maeda, K; Margaryan, A; Markowitz, P; Maruta, T; Matsumura, A; Maxwell, V; Mkrtchyan, A; Mkrtchyan, H; Nagao, S; Nakamura, S N; Narayan, A; Neville, C; Niculescu, G; Niculescu, M I; Nunez, A; Nuruzzaman,; Okayasu, Y; Petkovic, T; Pochodzalla, J; Qiu, X; Reinhold, J; Rodriguez, V M; Samanta, C; Sawatzky, B; Seva, T; Shichijo, A; Tadevosyan, V; Tang, L; Taniya, N; Tsukada, K; Veilleux, M; Vulcan, W; Wesselmann, F R; Wood, S A; Yamamoto, T; Ya, L; Ye, Z; Yokota, K; Yuan, L; Zhamkochyan, S; Zhu, L

    2016-01-01

    The missing mass spectroscopy of the $^{7}_{\\Lambda}$He hypernucleus was performed, using the $^{7}$Li$(e,e^{\\prime}K^{+})^{7}_{\\Lambda}$He reaction at JLab Hall-C. The $\\Lambda$ binding energy of the ground state (1/2$^{+}$) was determined with a smaller error than that of the previous measurement, being $B_{\\Lambda}$ = 5.55 $\\pm$ 0.10(stat.) $\\pm$ 0.11(sys.) MeV. The experiment also provided new insight into charge symmetry breaking in p-shell hypernuclear systems. Finally, a peak at $B_{\\Lambda}$ = 3.65 $\\pm$ 0.20(stat.) $\\pm$ 0.11(sys.) MeV was observed and assigned as a mixture of 3/2$^{+}$ and 5/2$^{+}$ states, confirming the "glue-like" behavior of $\\Lambda$, which makes an unstable state in $^{6}$He stable against neutron emission.

  10. The effect of Ar neutral beam treatment of screen-printed carbon nanotubes for enhanced field emission

    International Nuclear Information System (INIS)

    This study examined the effectiveness of an Ar neutral beam as a surface treatment for improving the field emission properties of screen-printed carbon nanotubes (CNTs). A short period of the neutral beam treatment on tape-activated CNTs enhanced the emission properties of the CNTs, showing a decrease in the turn-on field and an increase in the number of emission sites. The neutral beam treatment appeared to render the CNT surfaces more actively by exposing more CNTs from the CNT paste without cutting or kinking the already exposed long CNT emitters. The treated CNTs emitted more electrons than the CNTs treated using other methods. When the field emission properties were measured after the neutral beam treatment, the turn-on field decreased from 1.65 to 0.60 V/μm and the emission field at 1 mA/cm2 decreased from 3.10 to 2.41 V/μm. After the neutral beam treatment for 10 s, there was an improvement in the stability of the emission current at a constant electric field. It is expected that the neutral beam treatment introduced in this study will provide an easy way of improving the emission intensity and stability of screen-printed CNT emitters

  11. Gamma ray tracking with the AGATA demonstrator. A novel approach for in-beam spectroscopy

    International Nuclear Information System (INIS)

    -rays were detected with the AGATA demonstrator consisting of five AGATA triple cluster detectors. An additional micro channel plate detector for particle detection was mounted inside the scattering chamber in order to request kinematic coincidences. The analysis procedures for the two complex sub-detectors AGATA and PRISMA were extended and adapted to the specific requirements of this new approach for actinide spectroscopy. First the complex analysis of the magnetic spectrometer PRISMA and solutions for unexpected detector behaviour like time drifts and aberration corrections are described. As a result the individual isotopes of elements from Barium to Tellurium were identified confirming the very high quality of the PRISMA spectrometer and its design parameters. The analysis of the γ-ray spectra comprised a detailed PSA and GRT analysis of the AGATA demonstrator. This analysis included also data analysis developments for the AGATA collaboration. The data of the AGATA demonstrator, the PRISMA spectrometer and the ancillary detectors were merged to obtain background free Doppler corrected spectra for the beam- and target-like reaction products. The simultaneous Doppler correction for beam and target-like ions included an elaborate optimization procedure for unobservable experimental parameters. The γ-ray spectra for the individual isotopes is consistent with the isotope identification of the PRISMA analysis. For the beam like particles γ-ray spectra of the isotopes 128-139Xe are presented and discussed. For the target like nuclei γ-ray spectra of the isotopes 236-240U are deduced. By gating on the remaining excitation energy after the multi-nucleon transfer reaction the neutron evaporation and fission of the excited actinide nuclei were suppressed. Coincidences between AGATA and PRISMA were exploited for the first time together with the particle coincidence between beam- and target-like nuclei. These triple coincidences allowed further background reduction. The results

  12. Optical emission and mass spectroscopy of plasma processes in reactive DC pulsed magnetron sputtering of aluminium oxide

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Bulíř, Jiří; Pokorný, Petr; Bočan, Jiří; Fitl, Přemysl; Lančok, Ján; Musil, Jindřich

    2010-01-01

    Roč. 12, č. 3 (2010), 697-700. ISSN 1454-4164 R&D Projects: GA AV ČR IAA100100718; GA AV ČR KAN400100653; GA ČR GP202/09/P324 Institutional research plan: CEZ:AV0Z10100522 Keywords : reactive magnetron sputtering * alumina * plasma spectroscopy * mass spectroscopy * optical emission spectroscopy Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.412, year: 2010

  13. Measuring the Density of a Molecular Cluster Injector via Visible Emission from an Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, D. P.; Kaita, R.; Majeski, R. M.; Stotler, D. P.

    2010-06-28

    A method to measure the density distribution of a dense hydrogen gas jet is pre- sented. A Mach 5.5 nozzle is cooled to 80K to form a flow capable of molecular cluster formation. A 250V, 10mA electron beam collides with the jet and produces Hα emission that is viewed by a fast camera. The high density of the jet, several 1016cm-3, results in substantial electron depletion, which attenuates the Hα emission. The attenuated emission measurement, combined with a simplified electron-molecule collision model, allows us to determine the molecular density profile via a simple iterative calculation.

  14. Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

    Energy Technology Data Exchange (ETDEWEB)

    Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

    2012-12-15

    Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

  15. Current control of the electron beam formed in the magnetron gun with a secondary-emission cathode

    International Nuclear Information System (INIS)

    Data are reported on electron beam generation and beam current control in two types of secondary-emission cathode magnetron guns. The influence of the magnetic field value and field distribution on the formation of the beam and its parameters has been investigated in the electron energy range between 20 and 150 keV. The influence of local magnetic field variations on the cathode and the electron beam characteristics has been studied. The possibility to control the electron beam current in various ways has been demonstrated

  16. Application of filter method for detection of secondary electron emission in the auto-oscillating mode of beam plasma discharge

    Science.gov (United States)

    Balovnev, A. V.; Vizgalov, I. V.; Salahutdinov, G. H.

    2016-01-01

    In this paper we studied the non-self mode of the auto-oscillation secondary- emission discharge (ASED) in a longitudinal magnetic field with autonomous electron gun to ignite the primary beam-plasma discharge (PPD).

  17. Analysis of two colliding laser-produced plasmas by emission spectroscopy and fast photography

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Ake, C., E-mail: citlali.sanchez@ccadet.unam.m [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Mustri-Trejo, D. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Garcia-Fernandez, T. [Universidad Autonoma de la Ciudad de Mexico, Prolongacion San Isidro 151, Col. San Lorenzo Tezonco, Mexico DF, C.P. 09790 (Mexico); Villagran-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico)

    2010-05-15

    In this work two colliding laser-induced plasmas (LIP) on Cu and C were studied by means of time resolved emission spectroscopy and fast photography. The experiments were performed using two opposing parallel targets of Cu and C in vacuum, ablated with two synchronized ns lasers. The results showed an increased emission intensity from copper ions Cu II (368.65, 490.97, 493.16, 495.37 and 630.10 nm) and Cu III (374.47 and 379.08 nm) due to the ionization that occurs during collisions of Cu and C species. It was found that the optimum delay between pulses, which yields the maximum emission enhancement of Cu ions, depends on the sampling distance. On the other hand, the emission intensity of C lines, C II (426.70 nm), C III (406.99 and 464.74 nm) and C IV (465.83 nm), decreased and the formation of C{sub 2} molecules was observed. A comparison between the temporal evolution of the individual plasmas and their collision performed by combining imaging and the time resolved emission diagnostics, revealed an increase of the electron temperature and electron density and the splitting of the plume into slow and fast components.

  18. Boosting persistence time of laser-induced plasma by electric arc discharge for optical emission spectroscopy

    International Nuclear Information System (INIS)

    Plasma induced by nanosecond laser ablation is re-excited by a pulsed electric discharge and the parameters and optical emission of the plasma are measured. The discharge is a low-voltage and high-current electric arc that is triggered by the laser-induced plasma and slowly decaying with time. The optical emission of such combined plasma lasts up to several milliseconds which is much longer than without re-excitation (μs range). The emission spectra of re-excited plasma measured on different sample materials show higher line intensities than spectra measured by conventional laser-induced breakdown spectroscopy (LIBS). Moreover, emission lines of fluorine (spectral range 683–691 nm) and sulfur (range 520–550 nm) not detected by conventional LIBS become easily detectable with the combined plasma. The concentration of major components in metallurgical slags, as determined by calibration-free LIBS, agrees very well to the reference data evaluating the spectra taken from re-excited plasma. - Highlights: • Persistence time of laser-induced plasma in air is increased from ~ 10 μs to ~ 1 ms. • Laser-induced plasma triggers an electric arc discharge that boosts the plasma. • The combined laser-arc plasma is in LTE state over very long time (ms range). • CF-LIBS method delivers accurate results evaluating spectra of combined plasma. • Emission from S and F, not detected by LIBS, is detected with combined plasma

  19. Spatially-resolved HST Grism Spectroscopy of a Lensed Emission Line Galaxy at z~1

    CERN Document Server

    Frye, Brenda L; Bowen, David V; Meurer, Gerhardt; Sharon, Keren; Straughn, Amber; Coe, Dan; Broadhurst, Tom; Guhathakurta, Puragra

    2012-01-01

    We take advantage of gravitational lensing amplification by Abell 1689 (z=0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i_775=27.3 via slitless grism spectroscopy. One ELG (at z=0.7895) is very bright owing to lensing magnification by a factor of ~4.5. Several Balmer emission lines detected from ground-based follow-up spectroscopy signal the onset of a major starburst for this low-mass galaxy (M_* = 2 x 10^9 solar masses) with a high specific star formation rate (~20 /Gyr). From the blue emission lines we measure a gas-phase oxygen abundance consistent with solar (12+log(O/H)=8.8 +/- 0.2). We break the continuous line-emitting region of this giant arc into seven ~1kpc bins (intrinsic size) and measure a variety of metallicity dependent line ratios. A weak trend of increasing metal fraction is seen toward the dynamical center of the galaxy. Interestingly, the metal line ratios in a region...

  20. Spectral asymmetries in ground-state grating and stimulated emission pumping configurations of two-color resonant four-wave-mixing spectroscopy

    International Nuclear Information System (INIS)

    The recent evolution toward resonant conditions of the two-color resonant four-wave-mixing (TC-RFWM) spectroscopy has been dictated by the high sensitivity required experimentally. While some models have been used in different contexts such as light pressure forces in strong polychromatic fields, magnetically assisted Sisyphus effect, or multiphoton resonances in Λ atoms, the existence in molecules of additional processes such as nonradiative transitions and rotational or vibrational dephasings requires the extension of previous models. For this reason, we give here a general description of the internal dynamics for a molecule undergoing two strong grating beams, acting either on two different transitions sharing a common level or on the same transition, and one weak probe beam to reproduce the ground-state grating and stimulated emission pumping configurations of TC-RFWM spectroscopy. By combining high spectral resolution and strong grating beams, we show that the TC-RFWM spectrum is very sensitive to the transition constants, dephasing constants, as well as to the transverse velocity of the molecules in the jet. The last case corresponding to a bichromatic field acting on a single transition is used to explain the origin of the line-shape asymmetry observed experimentally on jet-cooled molecules

  1. In situ measurement of neutral beam components using the Doppler-shifted Hα emissions in Heliotron E

    International Nuclear Information System (INIS)

    The density fraction of energy components (E,E/2,E/3,E/18) of the neutral beam was measured at the plasma center, using the Doppler-shifted Hα emissions, which were excited by electron and proton collisions in the plasma. This measurement will be useful in understanding the heating process by neutral beam injection. (author)

  2. Parameters Optimization of Laser-Induced Breakdown Spectroscopy Experimental Setup for the Case with Beam Expander

    Science.gov (United States)

    Wang, Xin; Zhang, Lei; Fan, Juanjuan; Li, Yufang; Gong, Yao; Dong, Lei; Ma, Weiguang; Yin, Wangbao; Jia, Suotang

    2015-11-01

    Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy (LIBS) technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander (BE). In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances: the signal to noise ratio (SNR) and the relative standard deviation (RSD). We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine (SVM) regression combined with principal component analysis (PCA) was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%. supported by the 973 Program of China (No. 2012CB921603), National Natural Science Foundation of China (Nos. 61475093, 61127017, 61178009, 61108030, 61378047, 61275213, 61475093, and 61205216), the National Key Technology R&D Program of China (No. 2013BAC14B01), the Shanxi Natural Science Foundation (Nos. 2013021004-1 and 2012021022-1), the Shanxi Scholarship Council of China (Nos. 2013-011 and 2013-01), and the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi, China

  3. Applying light-emitting diodes with narrowband emission features in differential spectroscopy.

    Science.gov (United States)

    Sihler, Holger; Kern, Christoph; Pöhler, Denis; Platt, Ulrich

    2009-12-01

    LEDs are a promising new type of light source for differential optical absorption spectroscopy (DOAS). Varying differential structures in the emission spectrum of LEDs, however, display a potentially severe problem. We show that the structures, which originate from a Fabry-Pérot etalon, may be removed by tilting the emitter, which at the same time increases the radiant flux coupled into the subsequent optical system. The results of long-path DOAS measurements, where we apply our method on a blue LED for the suppression of periodic structures, are also presented. PMID:19953172

  4. Remote gas analysis of aircraft exhausts using FTIR-emission-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Heland, J.; Schaefer, K. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

    1997-12-31

    FITR emission spectroscopy as a remote sensing multi-component analyzing technique was investigated to determine the composition of aircraft exhausts at ground level. A multi-layer radiative transfer interpretation software based on a line-by-line computer algorithm using the HITRAN data base was developed. Measurements were carried out with different engine types to determine the traceable gas species and their detection limits. Finally validation measurements were made to compare the results of the system to those of conventional equipment. (author) 8 refs.

  5. Elemental analysis of halogens using molecular emission by laser-induced breakdown spectroscopy in air

    International Nuclear Information System (INIS)

    Fluorine and chlorine do not produce atomic and ionic line spectra of sufficient intensity to permit their detection by laser-induced breakdown spectroscopy. They do, however, combine with alkali-earths and other elements to form molecules whose spectra may be easily identified, enabling detection in ambient conditions with much higher sensitivity than using F I and Cl I atomic lines. - Highlights: • We studied laser induced breakdown spectra of halogens with alkali-earth elements. • Emission and temporal behavior of CaF and CaCl molecules were determined. • Sensitivity of F and Cl detection by molecules and atoms was compared

  6. Elemental analysis of halogens using molecular emission by laser-induced breakdown spectroscopy in air

    Energy Technology Data Exchange (ETDEWEB)

    Gaft, M.; Nagli, L.; Eliezer, N.; Groisman, Y. [Laser Distance Spectrometry, 9 Mota Gur St., Petah Tikva 49514 (Israel); Forni, O. [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France)

    2014-08-01

    Fluorine and chlorine do not produce atomic and ionic line spectra of sufficient intensity to permit their detection by laser-induced breakdown spectroscopy. They do, however, combine with alkali-earths and other elements to form molecules whose spectra may be easily identified, enabling detection in ambient conditions with much higher sensitivity than using F I and Cl I atomic lines. - Highlights: • We studied laser induced breakdown spectra of halogens with alkali-earth elements. • Emission and temporal behavior of CaF and CaCl molecules were determined. • Sensitivity of F and Cl detection by molecules and atoms was compared.

  7. Phase-resolved optical emission spectroscopy for an electron cyclotron resonance etcher

    International Nuclear Information System (INIS)

    Phase-resolved optical emission spectroscopy (PROES) is used for the measurement of plasma products in a typical industrial electron cyclotron resonance (ECR) plasma etcher. In this paper, the PROES of oxygen and argon atoms spectral lines are investigated over a wide range of process parameters. The PROES shows a discrimination between the plasma species from gas phase and those which come from the solid phase due to surface etching. The relationship between the micro-wave and radio-frequency generators for plasma creation in the ECR can be better understood by the use of PROES.

  8. Phase-resolved optical emission spectroscopy for an electron cyclotron resonance etcher

    Energy Technology Data Exchange (ETDEWEB)

    Milosavljevic, Vladimir [BioPlasma Research Group, Dublin Institute of Technology, Sackville Place, Dublin 1 (Ireland); Biosystems Engineering, University College Dublin, Dublin 4, Ireland and Faculty of Physics, University of Belgrade, Belgrade (Serbia); MacGearailt, Niall; Daniels, Stephen; Turner, Miles M. [NCPST, Dublin City University, Dublin (Ireland); Cullen, P. J. [BioPlasma Research Group, Dublin Institute of Technology, Sackville Place, Dublin 1 (Ireland)

    2013-04-28

    Phase-resolved optical emission spectroscopy (PROES) is used for the measurement of plasma products in a typical industrial electron cyclotron resonance (ECR) plasma etcher. In this paper, the PROES of oxygen and argon atoms spectral lines are investigated over a wide range of process parameters. The PROES shows a discrimination between the plasma species from gas phase and those which come from the solid phase due to surface etching. The relationship between the micro-wave and radio-frequency generators for plasma creation in the ECR can be better understood by the use of PROES.

  9. SHM based on Acoustic Emission and Nonlinear Elastic Wave Spectroscopy with Time Reversal Mirrors

    Czech Academy of Sciences Publication Activity Database

    Převorovský, Zdeněk; Vejvodová, Šárka; Chlada, Milan; Krofta, Josef

    Drážďany: Fraunhofer Institute for Non-Destructive Testing Dresden Branch (IZFP-D), 2010, s. 1-1. ISBN N. [Dresden Aiport Seminar - Recent Trends in SHM and NDE /5./. Drážďany (DE), 03.11.2010-04.11.2010] R&D Projects: GA MPO(CZ) FR-TI1/274 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustic emission * nonlinear elastic wave spectroscopy * time reversal mirrors * defect detection * aircraft structural health monitoring Subject RIV: BI - Acoustics www.airportseminar.fraunhofer.de

  10. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    CERN Document Server

    Ho, I-Ting; Groves, Brent; Rich, Jeffrey A; Rupke, David S N; Hampton, Elise; Kewley, Lisa J; Bland-Hawthorn, Joss; Croom, Scott M; Richards, Samuel; Schaefer, Adam L; Sharp, Rob; Sweet, Sarah M

    2016-01-01

    We present LZIFU (LaZy-IFU), an IDL toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. LZIFU is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. LZIFU has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of LZIFU, demonstrating its accuracy and robustness. We also show examples of applying LZIFU to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line prof...

  11. Optimization and control of a plasma carburizing process by means of optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rie, K.-T.; Menthe, E.; Woehle, J. [TU Braunschweig (Germany). Inst. fuer Oberflaechentechnik und Plasmatechnische Werkstoffentwicklung

    1998-01-01

    In this work optical emission spectroscopy (OES) is used to characterize the dissociation process of methane in an argon/hydrogen/methane discharge for plasma carburizing. The optical emission spectra of the discharge have been measured as a function of process parameters: discharge voltage, pulse duration and pulse pause time. A correlation between the intensities of hydrocarbon molecules, carbon atoms and ions, and the carbon mass flow model of the carburizing process has been confirmed. The dominant species identified in the spectra used for correlation are excited and ionized carbon atoms, as well as excited carbon and hydrocarbon molecules such as excited CH with a molecular band at 431.42 nm and 314.41 nm, and excited C{sub 2} with molecular band at 501.50 nm. Excited carbon atoms at 493.21 nm and excited carbon ions at 387.17 nm and 426.70 nm are also detected. (orig.) 10 refs.

  12. Characterization of dielectric barrier discharge in air applying current measurement, numerical simulation and emission spectroscopy

    CERN Document Server

    Rajasekaran, Priyadarshini; Awakowicz, Peter

    2012-01-01

    Dielectric barrier discharge (DBD) in air is characterized applying current measurement, numerical simulation and optical emission spectroscopy (OES). For OES, a non-calibrated spectrometer is used. This diagnostic method is applicable when cross-sectional area of the active plasma volume and current density can be determined. The nitrogen emission in the spectral range of 380 nm- 406 nm is used for OES diagnostics. Electric field in the active plasma volume is determined applying the measured spectrum, well-known Frank-Condon factors for nitrogen transitions and numerically- simulated electron distribution functions. The measured electric current density is used for determination of electron density in plasma. Using the determined plasma parameters, the dissociation rate of nitrogen and oxygen in active plasma volume are calculated, which can be used by simulation of the chemical kinetics.

  13. X-ray absorption and X-ray emission spectroscopy theory and applications

    CERN Document Server

    Lamberti, Carlo

    2016-01-01

    During the last two decades, remarkable and often spectacular progress has been made in the methodological and instrumental aspects of x–ray absorption and emission spectroscopy. This progress includes considerable technological improvements in the design and production of detectors especially with the development and expansion of large-scale synchrotron reactors All this has resulted in improved analytical performance and new applications, as well as in the perspective of a dramatic enhancement in the potential of x–ray based analysis techniques for the near future. This comprehensive two-volume treatise features articles that explain the phenomena and describe examples of X–ray absorption and emission applications in several fields, including chemistry, biochemistry, catalysis, amorphous and liquid systems, synchrotron radiation, and surface phenomena. Contributors explain the underlying theory, how to set up X–ray absorption experiments, and how to analyze the details of the resulting spectra. X-R...

  14. Detection of bond failure in the anchorage zone of reinforced concrete beams via acoustic emission monitoring

    Science.gov (United States)

    Abouhussien, Ahmed A.; Hassan, Assem A. A.

    2016-07-01

    In this study, acoustic emission (AE) monitoring was utilised to identify the onset of bond failure in reinforced concrete beams. Beam anchorage specimens were designed and tested to fail in bond in the anchorage zone. The specimens included four 250 × 250 × 1500 mm beams with four variable bonded lengths (100, 200, 300, and 400 mm). Meanwhile, an additional 250 × 250 × 2440 mm beam, with 200 mm bonded length, was tested to investigate the influence of sensor location on the identification of bond damage. All beams were tested under four-point loading setup and continuously monitored using three distributed AE sensors. These attached sensors were exploited to record AE signals resulting from both cracking and bond deterioration until failure. The variations in the number of AE hits and cumulative signal strength (CSS) versus test time were evaluated to achieve early detection of crack growth and bar slippage. In addition, AE intensity analysis was performed on signal strength of collected AE signals to develop two additional parameters: historic index (H (t)) and severity (S r). The analysis of these AE parameters enabled an early detection of both first cracks (at almost the mid-span of the beam) and bar slip in either of the anchorage zones at the beams’ end before their visual observation, regardless of sensor location. The results also demonstrated a clear correlation between the damage level in terms of crack development/measured free end bar slip and AE parameters (number of hits, CSS, H(t), and S r).

  15. Phase resolved optical emission spectroscopy: a non-intrusive diagnostic to study electron dynamics in capacitive radio frequency discharges

    International Nuclear Information System (INIS)

    Various types of capacitively coupled radio frequency (CCRF) discharges are frequently used for different applications ranging from chip and solar cell manufacturing to the creation of biocompatible surfaces. In many of these discharges electron heating and electron dynamics are not fully understood. A powerful diagnostic to study electron dynamics in CCRF discharges is phase resolved optical emission spectroscopy (PROES). It is non-intrusive and provides access to the dynamics of highly energetic electrons, which sustain the discharge via ionization, with high spatial and temporal resolution within the RF period. Based on a time dependent model of the excitation dynamics of specifically chosen rare gas levels PROES provides access to plasma parameters such as the electron temperature, electron density and electron energy distribution function (EEDF). In this work the method of PROES is reviewed and some examples of its application are discussed. First, the generation of highly energetic electron beams by the expanding sheath in geometrically symmetric as well as asymmetric discharges and their effect on the EEDF are investigated. Second, the physical nature of the frequency coupling in dual frequency discharges operated at substantially different frequencies is discussed. Third, the generation of electric field reversals during sheath collapse in single and dual frequency discharges is analysed. Then excitation dynamics in an electrically asymmetric novel type of dual frequency discharge is studied. Finally, limitations of PROES are discussed.

  16. Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7

  17. Ion beam mixing in uranium nitride thin films studied by Rutherford Backscattering Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim-Ngan, N.-T.H., E-mail: tarnawsk@up.krakow.p [Institute of Physics, Pedagogical University, Podchorazych 2, 30-084 Krakow (Poland); Balogh, A.G. [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany); Havela, L. [Faculty of Mathematics and Physics, Charles University, 12116 Prague 2 (Czech Republic); Gouder, T. [European Commission, Joint Research Centre, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2010-06-15

    Thickness, composition, concentration depth profile and ion irradiation effects on uranium nitride thin films deposited on fused silica have been investigated by Rutherford Backscattering Spectroscopy (RBS) using 2 MeV He{sup +} ions. The films were prepared by reactive DC sputtering at the temperatures of -200 {sup o}C, +25 {sup o}C and +300 {sup o}C. A perfect 1U:1N stoichiometry with a layer thickness of 660 nm was found for the film deposited at -200 {sup o}C. An increase of the deposition temperature led to an enhancement of surface oxidation and an increase of the thickness of the mixed U-N-Si-O layers at the interface. The sample irradiation by 1 MeV Ar{sup +} ion beam with ion fluence of about 1.2-1.7 x 10{sup 16} ions/cm{sup 2} caused a large change in the layer composition and a large increase of the total film thickness for the films deposited at -200 {sup o}C and at +25 {sup o}C, but almost no change in the film thickness was detected for the film deposited at +300 {sup o}C. An enhanced mixing effect for this film was obtained after further irradiation with ion fluence of 2.3 x 10{sup 16} ions/cm{sup 2}.

  18. Acoustic emission monitoring of concrete columns and beams strengthened with fiber reinforced polymer sheets

    Science.gov (United States)

    Ma, Gao; Li, Hui; Zhou, Wensong; Xian, Guijun

    2012-04-01

    Acoustic emission (AE) technique is an effective method in the nondestructive testing (NDT) field of civil engineering. During the last two decades, Fiber reinforced polymer (FRP) has been widely used in repairing and strengthening concrete structures. The damage state of FRP strengthened concrete structures has become an important issue during the service period of the structure and it is a meaningful work to use AE technique as a nondestructive method to assess its damage state. The present study reports AE monitoring results of axial compression tests carried on basalt fiber reinforced polymer (BFRP) confined concrete columns and three-point-bending tests carried on BFRP reinforced concrete beams. AE parameters analysis was firstly utilized to give preliminary results of the concrete fracture process of these specimens. It was found that cumulative AE events can reflect the fracture development trend of both BFRP confined concrete columns and BFRP strengthened concrete beams and AE events had an abrupt increase at the point of BFRP breakage. Then the fracture process of BFRP confined concrete columns and BFRP strengthened concrete beams was studied through RA value-average frequency analysis. The RA value-average frequency tendencies of BFRP confined concrete were found different from that of BFRP strengthened concrete beams. The variation tendency of concrete crack patterns during the loading process was revealed.

  19. Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

    Directory of Open Access Journals (Sweden)

    Surała Władysław

    2016-06-01

    Full Text Available The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF experiments carried out within a modified PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8 measuring channels. For discharges performed with the pure deuterium filling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the first hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds and appearing in different instants after the current peculiarity (so-called current dip were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confirmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray films, showed the appearance of some filamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric, krypton (1.6% volumetric, or xenon (0.8% volumetric, decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes, which can be formed near the observed hot spots.

  20. Experimental observation of acoustic emissions generated by a pulsed proton beam from a hospital-based clinical cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin C.; Solberg, Timothy D.; Avery, Stephen, E-mail: Stephen.Avery@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Vander Stappen, François; Janssens, Guillaume; Prieels, Damien [Ion Beam Applications SA, Louvain-la-Neuve 1348 (Belgium); Bawiec, Christopher R.; Lewin, Peter A. [School of Biomedical Engineering, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Sehgal, Chandra M. [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-12-15

    Purpose: To measure the acoustic signal generated by a pulsed proton spill from a hospital-based clinical cyclotron. Methods: An electronic function generator modulated the IBA C230 isochronous cyclotron to create a pulsed proton beam. The acoustic emissions generated by the proton beam were measured in water using a hydrophone. The acoustic measurements were repeated with increasing proton current and increasing distance between detector and beam. Results: The cyclotron generated proton spills with rise times of 18 μs and a maximum measured instantaneous proton current of 790 nA. Acoustic emissions generated by the proton energy deposition were measured to be on the order of mPa. The origin of the acoustic wave was identified as the proton beam based on the correlation between acoustic emission arrival time and distance between the hydrophone and proton beam. The acoustic frequency spectrum peaked at 10 kHz, and the acoustic pressure amplitude increased monotonically with increasing proton current. Conclusions: The authors report the first observation of acoustic emissions generated by a proton beam from a hospital-based clinical cyclotron. When modulated by an electronic function generator, the cyclotron is capable of creating proton spills with fast rise times (18 μs) and high instantaneous currents (790 nA). Measurements of the proton-generated acoustic emissions in a clinical setting may provide a method for in vivo proton range verification and patient monitoring.

  1. Experimental observation of acoustic emissions generated by a pulsed proton beam from a hospital-based clinical cyclotron

    International Nuclear Information System (INIS)

    Purpose: To measure the acoustic signal generated by a pulsed proton spill from a hospital-based clinical cyclotron. Methods: An electronic function generator modulated the IBA C230 isochronous cyclotron to create a pulsed proton beam. The acoustic emissions generated by the proton beam were measured in water using a hydrophone. The acoustic measurements were repeated with increasing proton current and increasing distance between detector and beam. Results: The cyclotron generated proton spills with rise times of 18 μs and a maximum measured instantaneous proton current of 790 nA. Acoustic emissions generated by the proton energy deposition were measured to be on the order of mPa. The origin of the acoustic wave was identified as the proton beam based on the correlation between acoustic emission arrival time and distance between the hydrophone and proton beam. The acoustic frequency spectrum peaked at 10 kHz, and the acoustic pressure amplitude increased monotonically with increasing proton current. Conclusions: The authors report the first observation of acoustic emissions generated by a proton beam from a hospital-based clinical cyclotron. When modulated by an electronic function generator, the cyclotron is capable of creating proton spills with fast rise times (18 μs) and high instantaneous currents (790 nA). Measurements of the proton-generated acoustic emissions in a clinical setting may provide a method for in vivo proton range verification and patient monitoring

  2. Emission control of InGaN nanocolumns grown by molecular-beam epitaxy on Si(111) substrates

    International Nuclear Information System (INIS)

    This work studies the effect of the growth temperature on the morphology and emission characteristics of self-assembled InGaN nanocolumns grown by plasma assisted molecular beam epitaxy. Morphology changes are assessed by scanning electron microscopy, while emission is measured by photoluminescence. Within the growth temperature range of 750 to 650 deg. C, an increase in In incorporation for decreasing temperature is observed. This effect allows tailoring the InGaN nanocolumns emission line shape by using temperature gradients during growth. Depending on the gradient rate, span, and sign, broad emission line shapes are obtained, covering the yellow to green range, even yielding white emission.

  3. Transition rates and transition rate diagrams in atomic emission spectroscopy: A review

    International Nuclear Information System (INIS)

    In low pressure plasmas with low electron densities, such as glow discharges, radiative de-excitation is a major de-excitation process of most excited states. Their relative de-excitation rates can be determined by emission spectroscopy, making it possible to study excitation processes in these discharges. This is in contrast to denser plasmas, in which such considerations are usually based on relative populations of excited states and concepts related to thermodynamic equilibrium. In the approach using reaction rates rather than populations, a convenient tool is the recently introduced formalism of transition rate diagrams. This formalism is reviewed, its relevance to different plasmas is discussed and some recent results on glow discharge excitation of manganese, copper and iron ions are presented. The prospects for the use of this formalism for the comparison of rate constants and cross sections for charge transfer reactions with argon ions of elements of interest in analytical glow discharge spectroscopy are discussed. - Highlights: • Radiative deexcitation is a major deexcitation process in some plasmas. • Rates of radiative transitions can be presented in transition rate diagrams. • Transition rate diagrams can be calculated based on emission spectra. • Transition rate diagrams can indicate collisional excitation processes. • Transition rate diagrams of Fe II, Cu II, Mn II in a glow discharge plasma are reviewed

  4. Emission Fourier transform spectroscopy for the remote sensing of the atmosphere

    Science.gov (United States)

    Bianchini, Giovanni; Cortesi, Ugo; Palchetti, Luca

    2002-02-01

    Fourier transform spectrometers (FTS), thanks to their intrinsic advantages of high throughput, high spectral resolution and multiplex acquisition of spectral channels, offer a powerful tool for the characterisation of the Earth's atmosphere. The use of photon noise limited detectors in FTS instruments operating in the middle/far infrared spectral region permits high sensitivity emission spectroscopy measurements, without the limitations arising from the use of an external radiation source. The wide operating spectral range of FTS instruments makes possible simultaneous detection of different atmospheric chemical species that show rotational and vibrational spectral bands in the middle/far infrared region. Spatially resolved measurements of the concentration of the interesting species are of fundamental interest in the study of local phenomena in atmospheric chemistry and physics, and can be obtained through the use of various observation and data inversion techniques. Among these, the best results in terms of vertical resolution are achieved through the limb sounding observation technique from airborne platform. As an example of possibilities offered by the above considered technique, results obtained from the SAFIRE-A (Spectroscopy of the Atmosphere using Far InfraRed Emission-Airborne) during the Antarctic campaign APE-GAIA (Airborne Polar Experiment-Geophysica Aircraft In Antarctica, Ushuaia, Argentina, September-October, 1999) are presented.

  5. Fluorescence excitation-emission matrix spectroscopy as a tool for determining quality of sparkling wines.

    Science.gov (United States)

    Elcoroaristizabal, Saioa; Callejón, Raquel M; Amigo, Jose M; Ocaña-González, Juan A; Morales, M Lourdes; Ubeda, Cristina

    2016-09-01

    Browning in sparkling wines was assessed by the use of excitation-emission fluorescence spectroscopy combined with PARAllel FACtor analysis (PARAFAC). Four different cava sparkling wines were monitored during an accelerated browning process and subsequently storage. Fluorescence changes observed during the accelerated browning process were monitored and compared with other conventional parameters: absorbance at 420nm (A420) and the content of 5-hydroxymethyl-2-furfural (5-HMF). A high similarity of the spectral profiles for all sparkling wines analyzed was observed, being explained by a four component PARAFAC model. A high correlation between the third PARAFAC factor (465/530nm) and the commonly used non-enzymatic browning indicators was observed. The fourth PARAFAC factor (280/380nm) gives us also information about the browning process following a first order kinetic reaction. Hence, excitation-emission fluorescence spectroscopy, together with PARAFAC, provides a faster alternative for browning monitoring to conventional methods, as well as useful key indicators for quality control. PMID:27041327

  6. Freshness estimation of intact frozen fish using fluorescence spectroscopy and chemometrics of excitation-emission matrix.

    Science.gov (United States)

    ElMasry, Gamal; Nagai, Hiroto; Moria, Keisuke; Nakazawa, Naho; Tsuta, Mizuki; Sugiyama, Junichi; Okazaki, Emiko; Nakauchi, Shigeki

    2015-10-01

    The current study attempted to provide a convenient, non-invasive and time-saving method to estimate the freshness of intact horse mackerel (Trachurus japonicus) fish in a frozen state using autofluorescence spectroscopy in tandem with multivariate analysis of fluorescence excitation-emission matrices (EEM). The extracted fluorescence data from different freshness conditions were pretreated, masked and reorganized to resolve fish fluorescence spectra from overlapping signals and scattering profiles for detecting and characterizing freshness changes. The real freshness values of the examined fish samples were then traditionally determined by the hard chemical analysis using the high performance liquid chromatography (HPLC) method and expressed as K-values. The fluorescence EEM data and the real freshness values were modeled using partial least square (PLS) regression and a novel algorithm was proposed to identify the ideal combinations of excitation and emission wavelengths being used as perfect predictors. The results revealed that freshness of frozen fish could be accurately predicted with R(2) of 0.89 and root mean square error estimated by cross validation (RMSECV) of 9.66%. This work substantially demonstrated that the autofluorescence spectroscopy associated with the proposed technical approaches has a high potential in non-destructive sensing of fish freshness in the frozen state. PMID:26078142

  7. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  8. Glow discharge optical emission spectroscopy: a complementary technique to analyze thin electrodeposited polyaniline films

    International Nuclear Information System (INIS)

    Glow Discharge Optical Emission Spectroscopy (GDOES) has been developed to perform depth profiles of thick metallic films, in tens of microns range. GDOES spectroscopy can also be used to analyze thin organic polymer films since this technique has a great potential thanks to its high depth resolution, multi-element capability, sensitivity, and adaptability to solids or films and to conducting or non-conducting samples. In particular thin electrodeposited conducting polymer films remain an unexplored field of investigation for GDOES technique. However GDOES was used in this work to analyze electrodeposited polyaniline films, in addition to other techniques such as profilometry, electron microscopy and X-ray diffraction (XRD). More precisely polyaniline thin films were electrodeposited from HCl solutions and the presence of an anilinium chloride excess at the top surface of the polymer film was demonstrated using GDOES and XRD. Rinsing of these films with water led to the removal of this excess and to the partial dedoping of the polymer film due to the porous structure of polymer films. Polyaniline thin films were also electrodeposited from H2SO4 solutions and an anilinium hydrogen sulfate was similarly observed at the top surface of the polymer. This excess was removed by rinsing, contrary to hydrogen sulfate anions incorporated into the polymer film during the electrochemical polymerization that were not completely expulsed from the polyaniline films as proved using GDOES. - Highlights: • Polyaniline films were electrodeposited from HCl and H2SO4 solutions • Polymer films were analyzed by Glow Discharge Optical Emission Spectroscopy (GDOES) • The incorporation of anions in the films was proved using GDOES depth profiles • The crystalline structure of polyaniline films was modified by water rinsing

  9. Optical emission enhancement in laser-induced breakdown spectroscopy using micro-torches

    Science.gov (United States)

    Liu, L.; Huang, X.; Li, S.; Lu, Yao; Chen, K.; Lu, Y. F.

    2016-03-01

    A cost effective method for optical emission enhancement in laser-induced breakdown spectroscopy (LIBS) has been proposed in this research. The pulsed Nd:YAG laser with a wavelength of 532 nm was used for sample ablation and plasma generation. A cost effective commercial butane micro-torch was put parallel to the sample surface to generate a small flame above the surface. The laser-induced plasma expanded in the flame environment. The time-resolved optical emission intensity and signal-to-noise ratio (SNR) have been observed with and without micro torch. For laser with pulse energy of 20 mJ, the relationship between optical emission intensity and delay time indicates that signal intensities have been greatly enhanced in the initial several microseconds when using micro torch. The time-resolved study of signal-to-noise ratio shows that the maximum SNR occurs at the delay time of 2 μs. The laser energy effects on the enhancements of optical emission intensity and SNR have also been analyzed, which indicates that the enhancement factors are both delay time and laser energy dependent. The maximum enhancement factors for both optical emission intensity and SNR gradually decreases with the laser energy increase. The limits of detection (LODs) for aluminum (Al) and molybdenum (Mo) in steel have been estimated, which shows that the detection sensitivity has been improved by around 4 times. The LODs of Al and Mo have been reduced from 18 to 6 ppm and from 110 to 36 ppm in LIBS, respectively. The method of LIBS by a micro torch has been demonstrated to be a cost effective method for detection sensitivity improvement, especially in the situation of low laser pulse energy.

  10. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  11. Mineral distribution in rice: Measurement by Microwave Plasma Atomic Emission Spectroscopy (MP-AES)

    International Nuclear Information System (INIS)

    Microwave Plasma Atomic Emission Spectroscopy (MP-AES) is a new technology with comparable performance and sensitivity to Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Both instrument use plasma as the energy source that produces atomic and ionic emission lines. However, MP-AES uses nitrogen as the plasma gas instead of argon which is an additional expense for ICP-OES. Thus, MP-AES is more economical. This study quantified six essential minerals (Se, Zn, Fe, Cu, Mn and K) in rice using MP-AES. Hot plate digestion was used for sample extraction and the detection limit for each instrument was compared with respect to the requirement for routine analysis in rice. Black, red and non-pigmented rice samples were polished in various intervals to determine the concentration loss of minerals. The polishing time corresponds to the structure of the rice grains such as outer bran layer (0 to 15), inner bran layer (15 to 30), outer endosperm layer (30 to 45), and middle endosperm layer (45 to 60). Results of MP-AES analysis showed that black rice had all essential materials (except K) in high concentration at the outer bran layer. The red and non-pigmented rice samples on the other hand, contained high levels of Se, Zn, Fe, and Mn in the whole bran portion. After 25 seconds, the mineral concentrations remained constant. The concentration of Cu however, gave consistent value in all polishing intervals, hence Cu might be located in the inner endosperm layer. Results also showed that K was uniformly distributed in all samples where 5% loss was consistently observed for every polishing interval. Therefore, the concentration of K was also affected by polishing time. Thus, the new MP-AES technology with comparable performance to ICP-OES is a promising tool for routine analysis in rice. (author)

  12. Automatic estimation of varying continuum background emission in laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    In laser-induced breakdown spectroscopy (LIBS), plasma emission is extremely unstable because of many factors, such as the fluctuation of laser energy, inhomogeneity of sample surfaces, and variable distance between lens and samples. Therefore, the detection and correction of varying continuum background emission are not easily accomplished. The aim of this work is to present a method that can automatically estimate and correct varying continuum background emission, which is representative in laser-induced plasma. In this method, we first find all minima on a spectrum, and then deduct the unreasonable minima by a proper threshold. Finally, we use one or multiple polynomial functions through the minima left to approximate the continuum backgrounds. The validity of this method was evaluated by using several spectra with different complexities and wavelength ranges. We also applied this method to optimize the measurement time delays of detectors. In addition, for five aluminum alloy samples, we compared their elemental calibration cures between original spectra and background-corrected spectra. Experimental results proved that the method proposed in this paper can well estimate varying continuum backgrounds over a wide range of wavelengths.

  13. Emission Spectroscopy and Radiometric Measurements in the NASA Ames IHF Arc Jet Facility

    Science.gov (United States)

    Winter, Michael W.; Raiche, George A.; Prabhu, Dinesh K.

    2012-01-01

    Plasma diagnostic measurement campaigns in the NASA Ames Interaction Heating Facility (IHF) have been conducted over the last several years with a view towards characterizing the flow in the arc jet facility by providing data necessary for modeling and simulation. Optical emission spectroscopy has been used in the plenum and in the free jet of the nozzle. Radiation incident over a probe surface has also been measured using radiometry. Plenum measurements have shown distinct radial profiles of temperature over a range of operating conditions. For cases where large amounts of cold air are added radially to the main arc-heated stream, the temperature profiles are higher by as much as 1500 K than the profiles assumed in flow simulations. Optical measurements perpendicular to the flow direction in the free jet showed significant contributions to the molecule emission through inverse pre-dissociation, thus allowing determination of atom number densities from molecular emission. This has been preliminarily demonstrated with the N2 1st Positive System. Despite the use of older rate coefficients, the resulting atom densities are reasonable and surprisingly close to flow predictions.

  14. Fluorescence excitation-emission matrix spectroscopy of vitiligo skin in vivo (Conference Presentation)

    Science.gov (United States)

    Zhao, Jianhua; Richer, Vincent; Al Jasser, Mohammed; Zandi, Soodabeh; Kollias, Nikiforos; Kalia, Sunil; Zeng, Haishan; Lui, Harvey

    2016-02-01

    Fluorescence signals depend on the intensity of the exciting light, the absorption properties of the constituent molecules, and the efficiency with which the absorbed photons are converted to fluorescence emission. The optical features and appearance of vitiligo have been explained primarily on the basis of reduced epidermal pigmentation, which results in abnormal white patches on the skin. The objective of this study is to explore the fluorescence properties of vitiligo and its adjacent normal skin using fluorescence excitation-emission matrix (EEM) spectroscopy. Thirty five (35) volunteers with vitiligo were acquired using a double-grating spectrofluorometer with excitation and emission wavelengths of 260-450 nm and 300-700 nm respectively. As expected, the most pronounced difference between the spectra obtained from vitiligo lesions compared to normally pigmented skin was that the overall fluorescence was much higher in vitiligo; these differences increased at shorter wavelengths, thus matching the characteristic spectral absorption of epidermal melanin. When comparing the fluorescence spectra from vitiligo to normal skin we detected three distinct spectral bands centered at 280nm, 310nm, and 335nm. The 280nm band may possibly be related to inflammation, whereas the 335 nm band may arise from collagen or keratin cross links. The source of the 310 nm band is uncertain; it is interesting to note its proximity to the 311 nm UV lamps used for vitiligo phototherapy. These differences are accounted for not only by changes in epidermal pigment content, but also by other optically active cutaneous biomolecules.

  15. Extraplanar Emission-Line Gas in Edge-On Spiral Galaxies. II. Optical Spectroscopy

    CERN Document Server

    Miller, S T; Miller, Scott T.; Veilleux, Sylvain

    2003-01-01

    The results from deep long-slit spectroscopy of nine edge-on spiral galaxies with known extraplanar line emission are reported. Emission from Halpha, [N II] lambda 6548, 6583, and [S II] lambda 6716, 6731 is detected out to heights of a few kpc in all of these galaxies. Several other fainter diagnostic lines such as [O I] lambda 6300, [O III] lambda 4959, 5007, and He I lambda 5876 are also detected over a smaller scale. The relative strengths, centroids and widths of the various emission lines provide constraints on the electron density, temperature, reddening, source(s) of ionization, and kinematics of the extraplanar gas. In all but one galaxy, photoionization by massive OB stars alone has difficulties explaining all of the line ratios in the extraplanar gas. Hybrid models that combine photoionization by OB stars and another source of ionization such as photoionization by turbulent mixing layers or shocks provide a better fit to the data. The (upper limits on the) velocity gradients measured in these galax...

  16. Undistorted X-ray Absorption Spectroscopy Using s-Core-Orbital Emissions.

    Science.gov (United States)

    Golnak, Ronny; Xiao, Jie; Atak, Kaan; Unger, Isaak; Seidel, Robert; Winter, Bernd; Aziz, Emad F

    2016-05-12

    Detection of secondary emissions, fluorescence yield (FY), or electron yield (EY), originating from the relaxation processes upon X-ray resonant absorption has been widely adopted for X-ray absorption spectroscopy (XAS) measurements when the primary absorption process cannot be probed directly in transmission mode. Various spectral distortion effects inherent in the relaxation processes and in the subsequent transportation of emitted particles (electron or photon) through the sample, however, undermine the proportionality of the emission signals to the X-ray absorption coefficient. In the present study, multiple radiative (FY) and nonradiative (EY) decay channels have been experimentally investigated on a model system, FeCl3 aqueous solution, at the excitation energy of the Fe L-edge. The systematic comparisons between the experimental spectra taken from various decay channels, as well as the comparison with the theoretically simulated Fe L-edge XA spectrum that involves only the absorption process, indicate that the detection of the Fe 3s → 2p partial fluorescence yield (PFY) gives rise to the true Fe L-edge XA spectrum. The two key characteristics generalized from this particular decay channel-zero orbital angular momentum (i.e., s orbital) and core-level emission-set a guideline for obtaining undistorted X-ray absorption spectra in the future. PMID:27101344

  17. Characterization of sheet electron beams from planar crossed-field secondary emission diodes

    International Nuclear Information System (INIS)

    Sheet electron beams of 9 cm width having linear current densities of 1.5-3.0 A/cm have been generated from a planar crossed-field secondary emission (CFSE) electron source operated at ∼20 kV diode voltage. The output electron beam consists of two parallel closely spaced sheets of electron flow originated from each side of the cathode. The full width at half maximum of each electron sheet is 1-2 mm depending on the magnetic field strength. The output current depends strongly on the diode voltage as I∝Un where n=5.0±0.5. At a given magnetic field strength B, there is a minimal diode voltage Umin at which the diode is able to maintain a self-sustained operation. The values of Umin for a range of magnetic fields B have been linked to the potential of the diode electron flow V0=0.42 kV which is approximately ten times greater than the first cross-over voltage in the secondary emission coefficient function. The planar CFSE electron source is capable of operating in a long ∼2 ms regime. The generation of low-voltage (-2 mbar has been also demonstrated

  18. Self-corrected sensors based on atomic absorption spectroscopy for atom flux measurements in molecular beam epitaxy

    International Nuclear Information System (INIS)

    A high sensitivity atom flux sensor based on atomic absorption spectroscopy has been designed and implemented to control electron beam evaporators and effusion cells in a molecular beam epitaxy system. Using a high-resolution spectrometer and a two-dimensional charge coupled device detector in a double-beam configuration, we employ either a non-resonant line or a resonant line with low cross section from the same hollow cathode lamp as the reference for nearly perfect background correction and baseline drift removal. This setup also significantly shortens the warm-up time needed compared to other sensor technologies and drastically reduces the noise coming from the surrounding environment. In addition, the high-resolution spectrometer allows the most sensitive resonant line to be isolated and used to provide excellent signal-to-noise ratio

  19. Photon detection system for laser spectroscopy experiments with cooled/bunched beams at BECOLA facility at NSCL

    Science.gov (United States)

    Hughes, Maximilian; Minamisono, Kei; Mantica, Paul; Rossi, Dominic; Ryder, Caleb; Klose, Andrew; Tarazona, David; Strum, Ryan; Bollen, Georg; Ringle, Ryan; Barquest, Brad; Geppert, Christopher

    2013-10-01

    The BEam COoler and LAser spectroscopy (BECOLA) facility at NSCL is designed to determine fundamental properties of the atomic nucleus such as the charge radii, the spin and electromagnetic moments. Commissioning tests of BECOLA has been completed using a stable 39K beam produced from an offline ion source. The 39K beam was cooled and bunched and propagated collinearly with laser light. The resulting fluorescence was detected in a photomultiplier tube (PMT)sensitive to the wavelength of D1 transition of 39K The PMT was cooled to minimize background due to dark counts. The resulting fluorescence light was measured as a function of laser frequency and time relative to the 39K beam bunch. An EPICS-based Control Systems Studio (CSS) was used for data acquisition and the software package Root was used for data analysis. The performance characteristics of the photon detection system as well as the laser spectroscopy of bunched 39K will be discussed. Work was supported in part by the National Science Foundation, Grant PHY-11-02511.

  20. Application of acoustic emission for assessing corrosion damage reinforced concrete beams

    International Nuclear Information System (INIS)

    The acoustic emission (AE) behavior of reinforced concrete beams tested under flexural loading was investigated to characterize and identify the source of damage. This research was aimed at identifying the characteristic AE response associated with micro-crack development, localized crack propagation, corrosion, and debonding of the reinforcing steel. Concrete beams were prepared to isolate the damage mechanisms by using plain, notched-plain, reinforced, and corroded-reinforced specimens. The beams were tested using four-point cyclic step-loading. The AE response was analyzed to obtain key parameters such as the total number and rate of AE events, the amplitude and duration of the events, and the characteristic features of the waveform. Initial analysis of the AE signal has shown that a clear difference in the AE response is observed depending on the source of the damage. The Felicity ratio exhibited a correlation with the overall damage level, while the number of AE events during unloading can be an effective criterion to estimate the level of corrosion distress in reinforced concrete structures. Consequently, AE measurement characterization appears to provide a promising approach for estimating the level of corrosion distress in reinforced concrete structure.

  1. Extended radio emission in core-dominated quasars: implications for relativistic beaming hypothesis

    Science.gov (United States)

    Odo, F. C.; Ubachukwu, A. A.; Chukwude, A. E.

    2015-06-01

    This paper investigates a simple consequence of relativistic beaming and radio source orientation scenario for high-luminosity extragalactic radio sources, based on the distributions of core-luminosity ( P C ) and extended lobe luminosity ( P E ) in a sample of core-dominated quasars (CDQs). In this scenario, CDQs are believed to have their radio axes oriented at closer angles to the line of sight relative to their parent population of FR II radio galaxies. At this orientation, the core emission is greatly enhanced due to relativistic Doppler boosting and linear size ( D) foreshortened due to geometrical projection. A simple outcome of this is that the extended luminosity is expected to be orientation invariant. Our results show a fairly strong anti-correlation ( r˜-0.5) between the core-to-lobe luminosity ratio ( R), believed to be orientation dependent, and P E . Based on the assumption that FR II radio galaxies form the parent population of the CDQs, the observed R- P E anti-correlation in the CDQs is consistent with a bulk Lorentz factor in the range γ≈3-5 and cone angle for optimum beaming 11∘≤ ϕ c ≤17∘, for continuous jet model. Furthermore, there is a weak D- P E anti-correlation ( r˜-0.3). The results are consistent with relativistic beaming at largest scales, although intrinsic/asymmetries in the local environments cannot be completely ruled out.

  2. Pulse-periodic generation of supershort avalanche electron beams and X-ray emission

    Science.gov (United States)

    Baksht, E. Kh.; Burachenko, A. G.; Erofeev, M. V.; Tarasenko, V. F.

    2014-05-01

    Pulse-periodic generation of supershort avalanche electron beams (SAEBs) and X-ray emission in nitrogen, as well as the transition from a single-pulse mode to a pulse-periodic mode with a high repetition frequency, was studied experimentally. It is shown that, in the pulse-periodic mode, the full width at halfmaximum of the SAEB is larger and the decrease rate of the gap voltage is lower than those in the single-pulse mode. It is found that, when the front duration of the voltage pulse at a nitrogen pressure of 90 Torr decreases from 2.5 to 0.3 ns, the X-ray exposure dose in the pulse-periodic mode increases by more than one order of magnitude and the number of SAEB electrons also increases. It is shown that, in the pulse-periodic mode of a diffuse discharge, gas heating in the discharge gap results in a severalfold increase in the SAEB amplitude (the number of electrons in the beam). At a generator voltage of 25 kV, nitrogen pressure of 90 Torr, and pulse repetition frequency of 3.5 kHz, a runaway electron beam was detected behind the anode foil.

  3. Resonant x-ray emission spectroscopy of liquid water: novel instrumentation, high resolution, and the "map" approach

    OpenAIRE

    Weinhardt, L.

    2010-01-01

    Techniques to study the electronic structure of liquids are rare. Most recently, resonant x-ray emission spectroscopy (XES) has been shown to be an extremely versatile spectroscopy to study both occupied and unoccupied electronic states for liquids in thermodynamic equilibrium. However, XES requires high-brilliance soft x-ray synchrotron radiation and poses significant technical challenges to maintain a liquid sample in an ultra-high vacuum environment. Our group has therefore developed and c...

  4. Pre-concentration of Cr, Mn, Fe and Co of water sea and analysis by plasma emission spectroscopy - DCP

    International Nuclear Information System (INIS)

    Studies of separation and pre-concentration methods of chromium, manganese, iron and cobalt from seawater, that allow use control methods of 51 Cr, 54 Mn, 55,59 Fe, 58,59 Co with a better sensibility and the determination of this elements by atomic absorption spectroscopy or plasma emission spectroscopy are described. This methods of seawater analysis will use near the region of Angra I reactor. (author)

  5. A New Doppler Shift Spectroscopy for Measurement of Neutral Beam Profile

    Institute of Scientific and Technical Information of China (English)

    SHI Yue-Jiang; GAO Xiang; WAN Bao-Nian; WANG Guang-Qi; FU Jia; WU Zhen-Wei; CHANG Jia-Feng; SUN Dan-Peng; GAO Wei; HUANG Juan; ZHOU Qian

    2007-01-01

    A new diagnostic based on Doppler shift is designed to measure the power profile of a hydrogen or deuterium neutral beam on the magnetic confined fusion machines. The interference niters and multi-channel photon detector array (PDA) are the main components of this diagnosis. The multi-channel PDA measures the line integrated Doppler Ha signal emitted by the neutral beam at one section in two directions. The local intensity of neutral beam can be obtained with the tomography technique. Compared to the conventional calorimeter diagnoses, this diagnosis can provide the beam profile without blocking the injection of neutral beam.

  6. Continuous measurements of volcanic gases from Popocatepetl volcano by thermal emission spectroscopy

    Science.gov (United States)

    Taquet, Noemie; Stremme, Wolfgang; Meza, Israel; Grutter, Michel

    2016-04-01

    Passive volcanic gas emissions have been poorly studied despite their impact on the atmospheric chemistry with important consequences on its geochemical cycles and climate change on regional and global scale. Therefore, long-term monitoring of volcanic gas plumes and their composition are of prime importance for climatic models and the estimation of the volcanic contribution to climate change. We present a new measurement and analysis strategy based on remote thermal emission spectroscopy which can provide continuous (day and night) information of the composition of the volcanic plume. In this study we show results from the Popocatepetl volcano in Mexico with measurements performed during the year 2015 from the Altzomoni Atmospheric Observatory (19.12N, -98.65W, 3,985 masl). This site, which forms part of the RUOA (www.ruoa.unam.mx) and NDACC (https://www2.acom.ucar.edu/irwg) networks, is located north of the crater of this active volcano at 12 km distance. Emission spectra were recorded with an FTIR spectrometer (OPAG22, Bruker) at 0.5 cm-1 spectral resolution and processed using the SFIT4 radiative transfer and profile retrieval code, based on the Optimal Estimation method (Rodgers, 1976; 1990; 2000). This newly improved methodology is intercompared to a former retrieval strategy using measurements from 2008 and recent results of the variability of the SiF4/SO2 composition ratio during 2015 is presented. A discussion of how the new measurements improve the understating of the impact of volcanic gas emissions on the atmosphere on global and regional scale is included.

  7. Plasma diagnostics in gas metal arc welding by optical emission spectroscopy

    International Nuclear Information System (INIS)

    The plasma column in a metal inert gas welding process is investigated by optical emission spectroscopy and high-speed imaging. The concentration and repartition of iron vapours are measured and correlated with the plasma and electrode geometric configuration. Plasma temperatures and electron densities are also measured for each studied position in the plasma. The temperatures are calculated using two different methods, allowing validation of the local thermodynamic equilibrium state of the plasma. The results show a maximum temperature of 12 500 K in the upper part of the arc, away from the arc axis. The iron concentration reaches a maximum of 0.3% close to the anode and strongly decreases along both the vertical and radial directions. The plasma thermophysical properties, calculated from this plasma composition, are then discussed regarding the metal transfer mode.

  8. Measurement of temperature profiles in flames by emission-absorption spectroscopy

    Science.gov (United States)

    Simmons, F. S.; Arnold, C. B.; Lindquist, G. H.

    1972-01-01

    An investigation was conducted to explore the use of infrared and ultraviolet emission-absorption spectroscopy for determination of temperature profiles in flames. Spectral radiances and absorptances were measured in the 2.7-micron H2O band and the 3064-A OH band in H2/O2 flames for several temperature profiles which were directly measured by a sodium line-reversal technique. The temperature profiles, determined by inversion of the infrared and ultraviolet spectra, showed an average disagreement with line-reversal measurements of 50 K for the infrared and 200 K for the ultraviolet at a temperature of 2600 K. The reasons for these discrepancies are discussed in some detail.

  9. Determination of trace impurities in uranium hexafluoride using inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    A procedure has been developed to determine 30 trace elements in high-purity uranium hexafluoride (UF6) using inductively coupled plasma-atomic emission spectroscopy. The analytical method consists of a liquid-liquid extraction of the uranium from the trace impurities with a tri-(2-ethyl-hexyl)-phosphate (TEHP)-hexane mixture. A computer-controlled scanning monochromator system interfaced to an inductively coupled plasma (ICP) is then used to determine the levels of 30 trace elements present in the UF6. A single sample dissolution procedure is used for all elements investigated. This preliminary report details experimental work done to date as part of a countinuing program to determine metallic impurities in uranium by ICP

  10. Optical emission spectroscopy of various materials irradiated by soft x-ray free-electron laser

    Czech Academy of Sciences Publication Activity Database

    Cihelka, Jaroslav; Juha, Libor; Chalupský, Jaromír; Rosmej, F.B.; Renner, Oldřich; Saksl, K.; Hájková, Věra; Vyšín, Luděk; Galtier, E.; Schott, R.; Khorsand, A.R.; Riley, D.; Dzelzainis, T.; Nelson, A.; Lee, R. W.; Heimann, P.; Nagler, B.; Vinko, S.; Wark, J.; Whitcher, T.; Toleikis, S.; Tschentscher, T.; Fäustlin, R.; Wabnitz, H.; Bajt, S.; Chapman, H.; Krzywinski, J.; Sobierajski, R.; Klinger, D.; Jurek, M.; Pelka, J.; Hau-Riege, S.; London, R.A.; Kuba, J.; Stojanovic, N.; Sokolowski-Tinten, K.; Gleeson, A.J.; Störmer, M.; Andreasson, J.; Hajdu, J.; Timneanu, N.

    Bellingham : SPIE, 2009 - (Juha, L.; Bajt, S.; Sobierajski, R.), 73610P/1-73610P/10 ISBN 9780819476357. ISSN 0277-786x. - (Proceedings of SPIE. 7361). [Damage to VUV, EUV, and X-Ray Optics II. Prague (CZ), 21.04.2009-23.04.2009] R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : optical emission spectroscopy * free-electron laser * atomic lines * plasma plume * warm dense matter Subject RIV: BH - Optics, Masers, Lasers http://dx.doi.org/10.1117/12.822766

  11. Plasma diagnostics in gas metal arc welding by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valensi, F; Pellerin, S; Zielinska, S [GREMI, Universite d' Orleans (Site de Bourges)/CNRS, BP 4043, 18028 Bourges cedex (France); Boutaghane, A [Universite des Sciences et de la Technologie Houari Boumediene, Alger (Algeria); Dzierzega, K [Marian Smoluchowski Institute of Physics, Jagellonian University, Krakow (Poland); Pellerin, N [CNRS, UPR3079 CEMHTI, 1D av. de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Briand, F, E-mail: flavien.valensi@laplace.univ-tsle.f, E-mail: stephane.pellerin@univ-orleans.f, E-mail: aboutaghane@yahoo.f, E-mail: krzycho@netmail.if.uj.edu.p, E-mail: sylwia.zielinska@airliquide.co, E-mail: nadia.pellerin@univ-orleans.f, E-mail: francis.briand@airliquide.co [CTAS-Air Liquide Welding, Saint Ouen l' Aumone, 95315 Cergy-Pontoise cedex (France)

    2010-11-03

    The plasma column in a metal inert gas welding process is investigated by optical emission spectroscopy and high-speed imaging. The concentration and repartition of iron vapours are measured and correlated with the plasma and electrode geometric configuration. Plasma temperatures and electron densities are also measured for each studied position in the plasma. The temperatures are calculated using two different methods, allowing validation of the local thermodynamic equilibrium state of the plasma. The results show a maximum temperature of 12 500 K in the upper part of the arc, away from the arc axis. The iron concentration reaches a maximum of 0.3% close to the anode and strongly decreases along both the vertical and radial directions. The plasma thermophysical properties, calculated from this plasma composition, are then discussed regarding the metal transfer mode.

  12. Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

    International Nuclear Information System (INIS)

    During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

  13. Sample preparation techniques in trace element analysis by X-ray emission spectroscopy

    International Nuclear Information System (INIS)

    The report, written under a research contract with the IAEA, contains a detailed presentation of the most difficult problem encountered in the trace element analysis by methods of the X-ray emission spectroscopy, namely the sample preparation techniques. The following items are covered. Sampling - with specific consideration of aerosols, water, soil, biological materials, petroleum and its products, storage of samples and their handling. Pretreatment of samples - preconcentration, ashing, solvent extraction, ion exchange and electrodeposition. Sample preparations for PIXE - analysis - backings, target uniformity and homogeneity, effects of irradiation, internal standards and specific examples of preparation (aqueous, biological, blood serum and solid samples). Sample preparations for radioactive sources or tube excitation - with specific examples (water, liquid and solid samples, soil, geological, plants and tissue samples). Finally, the problem of standards and reference materials, as well as that of interlaboratory comparisons, is discussed

  14. Inductively coupled plasma optical emission spectroscopy determination of trace element composition of argan oil.

    Science.gov (United States)

    Gonzálvez, A; Ghanjaoui, M E; El Rhazi, M; de la Guardia, M

    2010-02-01

    A methodology based on inductively coupled plasma optical emission spectroscopy (ICP-OES) after microwave assisted acid digestion has been developed to determine the trace element content of Moroccan argan oil. Limit of detection values equal or lower than few mg/kg were obtained for all elements under study. To assure the accuracy of the whole procedure, recovery studies were carried out on argan oil samples spiked at different concentration levels from 10 to 200 µg/L. Quantitative average recovery values were obtained for all elements evaluated, demonstrating the suitability of this methodology for the determination of trace elements in argan oil samples. Aluminum, calcium, chromium, iron, potassium, lithium, magnesium, sodium, vanadium and zinc were quantitatively determined in Moroccan argan oils being found that their concentration is different of that found in other edible oils thus offering a way for authentication and for the evaluation of possible adulterations. PMID:21339122

  15. Spatial phase-resolved optical emission spectroscopy for understanding plasma etching uniformity

    Science.gov (United States)

    Milosavljević, V.; Cullen, P. J.

    2015-05-01

    Plasma chemistry of an oxygen-argon discharge in an electron cyclotron resonance (ECR) plasma etcher with a SiO2 wafer is observed. The study involves: Phase-resolved optical emission spectroscopy (PROES) of neutral atomic argon (Ar I) and oxygen (O I) spectral lines, spectroscopic ellipsometry of the wafer and a magnetic-field measurement of the ECR etcher's electro-magnet. Spatial PROES results together with the ellipsometry and magnetic-field measurements are used to assess the plasma etching uniformity of the SiO2 wafer. To evaluate the cross-dependences of the measured outputs for a wide range of process parameters, a design-of-experiment approach is taken. Spatial PROES of the oxygen atom shows a different spectral radiation pattern for the oxygen from the gas phase and those from the solid phase due to surface etching.

  16. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Science.gov (United States)

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; Chiari, M.; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, D.; Zucchiatti, A.

    2016-03-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL)

  17. Model for efficient visible emission from Si nanocrystals ion beam synthesized in SiO2

    International Nuclear Information System (INIS)

    The photoluminescence (PL) emission of Si nanocrystals ion beam synthesized in SiO2 is studied in this work as a function of annealing time and initial Si atomic excess (super-saturation). The optical properties of this system have been correlated with the characteristics of the nanocrystal population. The Si nanocrystals show a wide and very intense PL red/infrared emission. This emission peaks at about 1.7 eV for the low super-saturation range between 1% and 10% and shifts to the infrared for higher super-saturation (20% and 30%). Remarkably, there is a linear increase of PL intensity versus super-saturation in the low range. Moreover, the annealing kinetic studies show a typical behavior of PL intensity with annealing time, with a fast transitory increase that bends over to reach asymptotic saturation. The PL intensity saturation is satisfactorily explained by the Ostwald ripening stage of the nanocrystal population while the transient stage is a consequence of both nanocrystal growth and nanocrystal surface passivation mechanisms acting together. Indeed, electron spin resonance measurements demonstrate that the concentration of Pb centers (Si dangling bonds) at the Si-SiO2 interface correlates inversely with PL intensity during most of the transient stage

  18. Plasma diagnostics by optical emission spectroscopy on argon and comparison with Thomson scattering

    International Nuclear Information System (INIS)

    A novel optical emission spectroscopy (OES) technique for the determination of electron temperatures and densities in low-pressure argon discharges is compared with Thomson scattering (TS). The emission spectroscopy technique is based on the measurement of certain line ratios in argon and a collisional-radiative model (CRM) including metastable transport. The investigations are carried out in a planar inductively coupled neutral loop discharge (NLD) over a wide range of pressures, p = 0.05 Pa-5 Pa. This discharge is a weakly magnetized novel radio-frequency (rf) plasma source, proposed for plasma etching. The NLD is operated in pure argon at a frequency of f = 13.56 MHz and powers varied between P = 1 kW and 2 kW. Both diagnostics, OES and TS, are applied in parallel. The electron energy distribution functions obtained by TS are clearly Maxwellian at low pressures but exhibit a certain enhancement of the energetic tail at higher pressures. Electron densities and temperatures obtained by both diagnostic techniques are compared. Further, absolute numbers of the metastable densities derived from the measurement by the CRM are compared with earlier measurements under similar conditions. Excellent agreement is found throughout if depletion of the neutral gas density by increasing gas temperature and electron pressure is included in the CRM. Electron pressure is the dominant depletion mechanism at gas pressures p ≤ 0.1 Pa and rf powers P > 1 kW. There, the electron pressure exceeds more than 3 times the neutral pressure and the ionization degree approaches 7% while at pressures p > 1 Pa the degree of ionization is relatively low (-3) and neutral gas depletion is dominated by gas heating.

  19. Electronic transitions and fermi edge singularity in polar heterostructures studied by absorption and emission spectroscopy

    Science.gov (United States)

    Pandey, S.; Cavalcoli, D.; Minj, A.; Fraboni, B.; Cavallini, A.; Gamarra, P.; Poisson, M. A.

    2012-12-01

    Optically induced electronic transitions in nitride based polar heterostructures have been investigated by absorption and emission spectroscopy. Surface photovoltage (SPV), photocurrent (PC), and photo luminescence spectroscopy have been applied to high quality InAlN/AlN/GaN structures to study the optical properties of two dimensional electron gas. Energy levels within the two dimensional electron gas (2DEG) well at the interface between the GaN and AlN have been directly observed by SPV and PC. Moreover, a strong enhancement of the photoluminescence intensity due to holes recombining with electrons at the Fermi Energy, known as fermi energy singularity, has been observed. These analyses have been carried out on InAlN/AlN/GaN heterojunctions with the InAlN barrier layer having different In content, a parameter which affects the energy levels within the 2DEG well as well as the optical signal intensity. The measured energy values are in a very good agreement with the ones obtained by Schrödinger-Poisson simulations.

  20. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    Science.gov (United States)

    Christensen, A. N.; Rydhög, J. S.; Søndergaard, R. V.; Andresen, T. L.; Holm, S.; Munck Af Rosenschöld, P.; Conradsen, K.; Jølck, R. I.

    2016-05-01

    Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively.Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The

  1. Two-step resonance ionization spectroscopy of Na atomic beam using cw and pulsed lasers

    International Nuclear Information System (INIS)

    Two-step photoionization of sodium atomic beam has been carried out using a cw and a pulsed dye lasers. Sodium ions have been detected by a time of flight method in order to reduce background noise. With a proper power of the pulsed dye laser the sodium atomic beam has been irradiated by a resonant cw dye laser. The density of the sodium atomic beam is estimated to be 103 cm-3 at the ionization area. (author)

  2. Nitrogen line spectroscopy of O-stars -- I. Nitrogen III emission line formation revisited

    CERN Document Server

    Gonzalez, Jorge G Rivero; Najarro, Francisco

    2011-01-01

    This is the first paper in a series dealing with optical Nitrogen spectroscopy of O-type stars, aiming at the analysis of Nitrogen abundances. We implemented a new Nitrogen model atom into the NLTE atmosphere/spectrum synthesis code FASTWIND, and compare the resulting optical NIII lines at 4634/40/42 A with other predictions, mostly from Mihalas & Hummer (1973, ApJ 179, 827,`MH'), and from the alternative code CMFGEN. Using similar model atmospheres as MH (not blanketed and wind-free), we are able to reproduce their results, in particular the triplet emission lines. According to MH, these should be strongly related to dielectronic recombination (DR) and the drain by certain two-electron transitions. However, using realistic, fully line-blanketed atmospheres at solar abundances, the key role of DR controlling these emission features is superseded -- for O-star conditions -- by the strength of the stellar wind and metallicity. In the case of wind-free models, the resulting lower ionizing EUV-fluxes severely...

  3. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    Science.gov (United States)

    Ho, I.-Ting; Medling, Anne M.; Groves, Brent; Rich, Jeffrey A.; Rupke, David S. N.; Hampton, Elise; Kewley, Lisa J.; Bland-Hawthorn, Joss; Croom, Scott M.; Richards, Samuel; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.

    2016-09-01

    We present lzifu (LaZy-IFU), an idl toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. lzifu is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. lzifu has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of lzifu, demonstrating its accuracy and robustness. We also show examples of applying lzifu to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line profiles presented in IFS data. The code is made available to the astronomy community through github. lzifu will be further developed over time to other IFS instruments, and to provide even more accurate line and uncertainty estimates.

  4. Emission spectroscopy measurements on an ECRH non-axisymmetric mirror plasma

    International Nuclear Information System (INIS)

    Time resolved visible emission spectroscopy (300-700 nm) has been performed on ECr heated He, N/sub 2/, and Ar plasmas in the Michigan Mirror Machine (MIMI). The plasma is generated and heated by whistler-mode ECRH at 7.43 GHz and 500W power in 400 μs pulses. Gas is puffed into the mid-plane region where a 2.5 cm quartz window is used to observe the plasma. The plasma is viewed in a direction perpendicular to the mirror axis. Emission spectra are obtained in 100 μs sampling periods starting from the microwave turn-on time using a 0.275 meter spectrograph coupled to a gated, intensified diode array. The majority of light is found to occur from 200-300 μs from microwave turn-on time. Thermal electron temperatures are inferred from the electronic temperature of Ar and He obtained from Atomic Boltzmann plots. Electron temperature varies from 1 eV to 50 eV depending upon gas pressure, microwave power, and mirror and quadrupole field strengths

  5. Spatial characterization of laser induced Yb plasma in argon using optical emission spectroscopy: Pressure effect

    International Nuclear Information System (INIS)

    Highlights: • Laser induced Yb plasma at different pressure of Argon is spatially investigated. • O-TOF profiles and excitation temperature are used to characterize the plasma. • At 100 Pa of argon background gas, shock wave begins to be formed. • Drag force expansion describes the plasma propagation at pressures bigger than 1 Pa. • Two components of velocity distribution of the Yb atoms are estimated. - Abstract: Spatial and temporal behavior of laser induced Ytterbium plasma plume is studied using optical emission spectroscopy technique. A third harmonic Nd:YAG nanosecond laser was used to generate Yb plasma plume at different Argon background pressures (1, 10, 102, 103 and 104 Pa). The plasma dynamics was investigated based on the spatial behavior of the excitation temperature coupled with optical time of flight (O-TOF) profiles of neutral Yb emission line (555.65 nm) along the propagation axe of the plasma plume. Drag force model was appropriate to describe the propagation dynamics at all pressures except of the lowest one (1 Pa) where free expansion model is dominant. The velocity distribution of Yb I atoms were extracted using two terms of Shifted Maxwell–Boltzmann (SMB) distribution. The correlation between the spatial comportment of both excitation temperature and O-TOF profiles is discussed

  6. Optical emission spectroscopy of oxygen plasma induced by IR CO2 pulsed laser

    Science.gov (United States)

    Camacho, J. J.; Santos, M.; Díaz, L.; Poyato, J. M. L.

    2008-11-01

    Laser-induced breakdown (LIB) spectroscopy in oxygen at room temperature and pressures ranging from 4.6 to 75 kPa was studied using a high-power transverse excitation atmospheric CO2 laser (λ = 9.621 and 10.591 µm τFWHM = 64 ns; power densities ranging from 0.87 to 6.31 GW cm-2). The spectrum of the generated plasma is dominated by emission of strong O, O+ and weak O2+ atomic lines. Excitation temperatures of 31 500 ± 1600 K and 23 000 ± 3000 K were estimated by means of O2+ and O+ ionic lines, respectively. Electron number densities of the order of (3.5-16.5) × 1016 cm-3 were deduced from the Stark broadening of several ionic O+ lines. The characteristics of the spectral emission intensities from different species have been investigated as functions of the oxygen pressure and laser irradiance. Optical breakdown threshold intensities in O2 at 10.591 µm have been determined. The physical processes leading to LIB of oxygen have been analysed.

  7. Optical emission spectroscopy of oxygen plasma induced by IR CO2 pulsed laser

    International Nuclear Information System (INIS)

    Laser-induced breakdown (LIB) spectroscopy in oxygen at room temperature and pressures ranging from 4.6 to 75 kPa was studied using a high-power transverse excitation atmospheric CO2 laser (λ = 9.621 and 10.591 μm; τFWHM = 64 ns; power densities ranging from 0.87 to 6.31 GW cm-2). The spectrum of the generated plasma is dominated by emission of strong O, O+ and weak O2+ atomic lines. Excitation temperatures of 31 500 ± 1600 K and 23 000 ± 3000 K were estimated by means of O2+ and O+ ionic lines, respectively. Electron number densities of the order of (3.5-16.5) x 1016 cm-3 were deduced from the Stark broadening of several ionic O+ lines. The characteristics of the spectral emission intensities from different species have been investigated as functions of the oxygen pressure and laser irradiance. Optical breakdown threshold intensities in O2 at 10.591 μm have been determined. The physical processes leading to LIB of oxygen have been analysed.

  8. Superficial dosimetry imaging of Čerenkov emission in electron beam radiotherapy of phantoms

    Science.gov (United States)

    Zhang, Rongxiao; Fox, Colleen J.; Glaser, Adam K.; Gladstone, David J.; Pogue, Brian W.

    2013-08-01

    Čerenkov emission is generated from ionizing radiation in tissue above 264 keV energy. This study presents the first examination of this optical emission as a surrogate for the absorbed superficial dose. Čerenkov emission was imaged from the surface of flat tissue phantoms irradiated with electrons, using a range of field sizes from 6 cm × 6 cm to 20 cm × 20 cm, incident angles from 0° to 50°, and energies from 6 to 18 MeV. The Čerenkov images were compared with the estimated superficial dose in phantoms from direct diode measurements, as well as calculations by Monte Carlo and the treatment planning system. Intensity images showed outstanding linear agreement (R2 = 0.97) with reference data of the known dose for energies from 6 to 18 MeV. When orthogonal delivery was carried out, the in-plane and cross-plane dose distribution comparisons indicated very little difference (±2-4% differences) between the different methods of estimation as compared to Čerenkov light imaging. For an incident angle 50°, the Čerenkov images and Monte Carlo simulation show excellent agreement with the diode data, but the treatment planning system had a larger error (OPT = ±1˜2%, diode = ±2˜3%, TPS = ±6-8% differences) as would be expected. The sampling depth of superficial dosimetry based on Čerenkov radiation has been simulated in a layered skin model, showing the potential of sampling depth tuning by spectral filtering. Taken together, these measurements and simulations indicate that Čerenkov emission imaging might provide a valuable method of superficial dosimetry imaging from incident radiotherapy beams of electrons.

  9. Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

    Directory of Open Access Journals (Sweden)

    Juliano Fujioka Mologni

    2010-04-01

    Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

  10. Far-red to near infrared emission and scattering spectroscopy for biomedical applications

    Science.gov (United States)

    Zhang, Gang

    2001-06-01

    The thesis investigates the far-red and near infrared (NIR) spectral region from biomedical tissue samples for monitoring the state of tissues. The NIR emission wing intensity is weak in comparison to the emission in the visible spectral region. The wing emission from biomedical samples has revealed meaningful information about the state of the tissues. A model is presented to explain the shape of the spectral wing based on a continuum of energy levels. The wing can be used to classify different kinds of tissues; especially it can be used to differentiate cancer part from normal human breast tissues. The research work of the far-red emission from thermal damaged tissue samples shows that the emission intensity in this spectral region is proportional to the extent of the thermal damage of the tissue. Near infrared spectral absorption method is used to investigate blood hemodynamics (perfusion and oxygenation) in brain during sleep-wake transition. The result of the research demonstrates that the continuous wave (CW) type near infrared spectroscopy (NIRS) device can be used to investigate brain blood perfusion and oxygenation with a similar precision with frequency domain (FD) type device. The human subject sleep and wake transition, has been monitored by CW type NIRS instrument with traditional electroencephalograph (EEG) method. Parallel change in oxy-Hb and deoxy-Hb is a discrete event that occurs in the transition from both sleep to wakefulness and wakefulness to sleep. These hemodynamic switches are generally about few seconds delayed from the human decided transition point between sleep and wake on the polygraph EEG recording paper. The combination of NIRS and EEG methods monitor the brain activity, gives more information about the brain activity. The sleep apnea investigation was associated with recurrent apneas, insufficient nasal continuous positive airway pressure (CPAP) and the different response of the peripheral and central compartments to breathing

  11. Spectroscopy of 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) attached to rare gas samples: Clusters vs. bulk matrices. II. Fluorescence emission spectroscopy

    OpenAIRE

    Dvorak, Matthieu; Mueller, Markus; Knoblauch, Tobias; Buenermann, Oliver; Rydlo, Alexandre; Minniberger, Stefan; Harbich, Wolfgang; Stienkemeier, Frank

    2012-01-01

    The interaction between 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) molecules and solid rare gas samples is studied by means of fluorescence emission spectroscopy. Laser-excited PTCDA-doped large argon, neon, and para-hydrogen clusters along with PTCDA embedded in helium nanodroplets are spectroscopically characterized with respect to line broadening and shifting. A fast non-radiative relaxation is observed before a radiative decay in the electronic ground state takes place. In co...

  12. Balmer-series emission cross-sections for the interaction between hydrogen neutral beams and molecular hydrogen: an annotated bibliography

    International Nuclear Information System (INIS)

    A detailed study of Balmer emission cross-sections in the interaction between hydrogen neutral beams and molecular hydrogen is presented. The relative importance of different processes leading to excited neutrals is reviewed. The effect of external perturbations on the excited levels of a neutral atom is taken into account. Finally an 'effective cross section' for the production of Doppler shifted and unshifted Hsub(α) emission line is proposed

  13. FEASIBILITY OF POSITRON EMISSION TOMOGRAPHY OF DOSE DISTRIBUTION IN PROTON BEAM CANCER THERAPY.

    Energy Technology Data Exchange (ETDEWEB)

    BEEBE - WANG,J.J.; DILMANIAN,F.A.; PEGGS,S.G.; SCHLYEER,D.J.; VASKA,P.

    2002-06-03

    Proton therapy is a treatment modality of increasing utility in clinical radiation oncology mostly because its dose distribution conforms more tightly to the target volume than x-ray radiation therapy. One important feature of proton therapy is that it produces a small amount of positron-emitting isotopes along the beam-path through the non-elastic nuclear interaction of protons with target nuclei such as {sup 12}C, {sup 14}N, and {sup 16}O. These radioisotopes, mainly {sup 11}C, {sup 13}N and {sup 15}O, allow imaging the therapy dose distribution using positron emission tomography (PET). The resulting PET images provide a powerful tool for quality assurance of the treatment, especially when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the dose distribution for treatment planning is more difficult. This paper uses Monte Carlo simulations to predict the yield of positron emitters produced by a 250 MeV proton beam, and to simulate the productions of the image in a clinical PET scanner.

  14. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography.

    Science.gov (United States)

    Christensen, A N; Rydhög, J S; Søndergaard, R V; Andresen, T L; Holm, S; Munck Af Rosenschöld, P; Conradsen, K; Jølck, R I

    2016-06-01

    Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive (106)Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively. PMID:27174233

  15. Electron beam technology for multipollutant emissions control from heavy fuel oil-fired boiler.

    Science.gov (United States)

    Chmielewski, Andrzej G; Ostapczuk, Anna; Licki, Janusz

    2010-08-01

    The electron beam treatment technology for purification of exhaust gases from the burning of heavy fuel oil (HFO) mazout with sulfur content approximately 3 wt % was tested at the Institute of Nuclear Chemistry and Technology laboratory plant. The parametric study was conducted to determine the sulfur dioxide (SO2), oxides of nitrogen (NO(x)), and polycyclic aromatic hydrocarbon (PAH) removal efficiency as a function of temperature and humidity of irradiated gases, absorbed irradiation dose, and ammonia stoichiometry process parameters. In the test performed under optimal conditions with an irradiation dose of 12.4 kGy, simultaneous removal efficiencies of approximately 98% for SO2, and 80% for NO(x) were recorded. The simultaneous decrease of PAH and one-ringed aromatic hydrocarbon (benzene, toluene, and xylenes [BTX]) concentrations was observed in the irradiated flue gas. Overall removal efficiencies of approximately 42% for PAHs and 86% for BTXs were achieved with an irradiation dose 5.3 kGy. The decomposition ratio of these compounds increased with an increase of absorbed dose. The decrease of PAH and BTX concentrations was followed by the increase of oxygen-containing aromatic hydrocarbon concentrations. The PAH and BTX decomposition process was initialized through the reaction with hydroxyl radicals that formed in the electron beam irradiated flue gas. Their decomposition process is based on similar principles as the primary reaction concerning SO2 and NO(x) removal; that is, free radicals attack organic compound chains or rings, causing volatile organic compound decomposition. Thus, the electron beam flue gas treatment (EBFGT) technology ensures simultaneous removal of acid (SO2 and NO(x)) and organic (PAH and BTX) pollutants from flue gas emitted from burning of HFO. This technology is a multipollutant emission control technology that can be applied for treatment of flue gas emitted from coal-, lignite-, and HFO-fired boilers. Other thermal processes such

  16. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  17. Near-infrared nano-spectroscopy and emission energy control of semiconductor quantum dots using a phase-change material

    International Nuclear Information System (INIS)

    We have proposed a method to achieve near-field imaging spectroscopy of single semiconductor quantum dots with high sensitivity by using an optical mask layer of a phase-change material. Sequential formation and elimination of an amorphous aperture allows imaging spectroscopy with high spatial resolution and high collection efficiency. We present numerical simulation and experimental result that show the effectiveness of this technique. Inspired by this optical mask effect, a new approach which can precisely control the emission energy of semiconductor quantum dots has been proposed. This method uses the volume expansion of a phase change material upon amorphization, which allows reversible emission energy tuning of quantum dots. A photoluminescence spectroscopy of single quantum dots and simulation were conducted to demonstrate and further explore the feasibility of this method

  18. Raman spectroscopy of visible-light photocatalyst - Nitrogen-doped titanium dioxide generated by irradiation with electron beam

    Science.gov (United States)

    Surmacki, Jakub; Wroński, Paweł; Szadkowska-Nicze, Magdalena; Abramczyk, Halina

    2013-04-01

    A promising material in medicine, optoelectronics, catalysis and photophysics, nitrogen-doped titanium dioxide, is investigated by means of vibrational spectroscopies: Raman and UV-Vis. The synthesis of N-doped TiO2 has been accomplished by oxidizing or reducing process either through chemical doping, and calcination or chemical doping enhanced by electron beam irradiation (EB). When ionizing radiation interacts with the polymorphic crystalline structure of TiO2 mixed with N-dopants (urea) active species such as free radicals are produced, thereby initiating chemical reactions that result in N-doping of the crystalline structure of TiO2. We have compared efficiency of doping by calcination and EB using Raman spectroscopy.

  19. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF +

    Science.gov (United States)

    Coe, J. V.; Owrutsky, J. C.; Keim, E. R.; Agman, N. V.; Hovde, D. C.; Saykally, R. J.

    1989-04-01

    We report the development of a new general technique for measuring vibration-rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration-rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v=0 and v=1 in the X 2Π state. Comparisons with many-body perturbation theory results are presented.

  20. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF/sup +/

    Energy Technology Data Exchange (ETDEWEB)

    Coe, J.V.; Owrutsky, J.C.; Keim, E.R.; Agman, N.V.; Hovde, D.C.; Saykally, R.J.

    1989-04-15

    We report the development of a new general technique for measuring vibration--rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration--rotation transitions of HF/sup +/ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v = 0 and v = 1 in the X /sup 2/Pi state. Comparisons with many-body perturbation theory results are presented.

  1. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF+

    International Nuclear Information System (INIS)

    We report the development of a new general technique for measuring vibration--rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration--rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v = 0 and v = 1 in the X 2Pi state. Comparisons with many-body perturbation theory results are presented

  2. Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements

    International Nuclear Information System (INIS)

    Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied

  3. Extended calibration range for prompt photon emission in ion beam irradiation

    CERN Document Server

    Bellini, F

    2014-01-01

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum.This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is report...

  4. Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements

    Science.gov (United States)

    Chérigier-Kovacic, L.; Ström, P.; Lejeune, A.; Doveil, F.

    2015-06-01

    Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied.

  5. Extended calibration range for prompt photon emission in ion beam irradiation

    International Nuclear Information System (INIS)

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum. This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80 MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is reported

  6. Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chérigier-Kovacic, L., E-mail: laurence.kovacic@univ-amu.fr; Doveil, F., E-mail: fabrice.doveil@univ-amu.fr [Aix-Marseille Université, CNRS, PIIM UMR 7345, FR-13397 Marseille Cedex 20 (France); Ström, P., E-mail: pestro@kth.se [Department of Fusion Plasma Physics, Royal Institute of Technology (KTH), Teknikringen 31, 100 44 Stockholm (Sweden); Lejeune, A., E-mail: aurelien.lejeune@ametek.com [CAMECA SAS - 29 Quai des Grésillons, 92622 Gennevilliers Cedex (France)

    2015-06-15

    Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied.

  7. Flue gas cleaning in power stations by using electron beam technology. Influence on PAH emissions

    International Nuclear Information System (INIS)

    The electron beam technology (EBT), proven treatment for SO2 and NOx removal, is applied to different power stations as hot gas cleaning system. In this paper, an assessment of this technique installed in a Bulgarian power station on organic emissions is analyzed. The Polycyclic Aromatic Hydrocarbons (PAH) content, not only emitted in the gas phase but also trapped in the solid phase, has been carried out before and after the irradiation. The main aim has been to know whether the EBT affects organic emissions, like PAH, as it happens with inorganic pollutants, like SO2 and NOx, studying EBT effects from an organic environmental point of view. The PAH quantification was performed by using a very sensitive analytical technique, gas chromatography with mass spectrometry mass spectrometry detection (GC-MS-MS). Results showed that PAH are influenced by the EBT showing a reduction of the most volatile PAH in the gas phase. PAH concentrations in the fertilizers obtained after irradiation were found to be similar to those in the fly ashes produced when no irradiation is applied. These fertilizers were considered like unpolluted soils being adequate for agriculture applications with PAH concentrations below the target value set up by the Dutch government. (author)

  8. Hot gas cleaning in power stations by using electron beam technology. Influence on PAH emissions

    International Nuclear Information System (INIS)

    The Electron Beam Technology (EBT), proven treatment for SO2 and NOx removal, is applied to different power stations as a hot gas cleaning system. In this paper, an assessment of this technique installed in a Bulgarian power station on organic emissions is analyzed. The Polycyclic Aromatic Hydrocarbons (PAH) content, not only emitted in the gas phase but also trapped in the solid phase, has been carried out before and after the irradiation. The main aim has been to know whether the EBT affects organic emissions, like PAH, as it happens with inorganic pollutants, like SO2 and NOx, studying EBT effects from an organic environmental point of view. The PAH quantification was performed by using a very sensitive analytical technique, gas chromatography with mass spectrometry mass spectrometry detection (GC-MS-MS). Results showed that PAH are influenced by the EBT showing a reduction of the most volatile PAH in the gas phase. With regard to the solid by-products obtained after the irradiation, fertilizers, similar PAH concentration to the fly ashes produced when no irradiation is applied were found. These fertilizers were considered like unpolluted soils being adequate for agriculture applications with PAH concentrations below the target value set up by the Dutch government. (author)

  9. Extended calibration range for prompt photon emission in ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bellini, F. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Boehlen, T.T.; Chin, M.P.W. [CERN, Geneva (Switzerland); Collamati, F. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Faccini, R., E-mail: riccardo.faccini@roma1.infn.it [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Ferrari, A. [CERN, Geneva (Switzerland); Lanza, L. [Dipartimento di Fisica, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Mancini-Terracciano, C. [CERN, Geneva (Switzerland); Dipartimento di Fisica, Università Roma Tre, Roma (Italy); Marafini, M. [Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Mattei, I. [Dipartimento di Fisica, Università Roma Tre, Roma (Italy); Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Morganti, S. [INFN Sezione di Roma, Roma (Italy); Ortega, P.G. [CERN, Geneva (Switzerland); Patera, V. [Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Università di Roma, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Piersanti, L. [Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Università di Roma, Roma (Italy); Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Russomando, A. [Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Roma (Italy); INFN Sezione di Roma, Roma (Italy); Sala, P.R. [INFN Sezione di Milano, Milano (Italy); and others

    2014-05-01

    Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum. This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80 MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is reported.

  10. X-ray emission spectroscopy study of the Verwey transition in Fe sub 3 O sub 4

    CERN Document Server

    Moewes, A; Finkelstein, L D; Galakhov, A V; Gota, S; Gautier-Soyer, M; Rueff, J P; Hague, C F

    2003-01-01

    The temperature-dependent Verwey transition in a 500 A (111) thin film of Fe sub 3 O sub 4 (magnetite) has been studied using soft-x-ray emission spectroscopy at room temperature and below the transition temperature T sub V. The Fe L sub 2 sub , sub 3 x-ray emission spectra show an increase in the intensity of the L sub 2 emission relative to the L sub 3 emission below T sub V. This is independent of the excitation energy and is attributed to a metal-insulator transition across T sub V. Comparison of the Fe L sub 3 emission and O K alpha spectra with LDA band structure calculations supports the suggestion of charge ordering in Fe sub 3 O sub 4 at low temperature.

  11. New approach to the nuclear in beam {gamma} spectroscopy of neutron rich nuclei at N=20 using projectile fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Jimenez, M.J.; Saint-Laurent, M.G.; Achouri, L.; Daugas, J.M. [Grand Accelerateur National d`Ions Lourds, 14 - Caen (France); Belleguic, M.; Azaiez, F.; Bourgeois, C. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Stanoiu, M.; Borcea, C. [Institute of Atomic Physics, Bucharest (Romania); Angelique, J.C. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire] [and others

    1999-11-01

    The structure of nuclei far from stability around {sup 32}Mg have been recently investigated by means of a novel method. In-beam {gamma}-decay spectroscopy of a large number of exotic neutron-rich nuclei produced by projectile fragmentation of a {sup 36}S projectile has been performed, using coincidences between the recoil fragments collected at the focal plane of SPEG spectrometer and {gamma}-rays emitted at the target location. Preliminary results on both the population mechanism and the decay of excited states in nuclei around {sup 32}Mg are presented. (author) 24 refs.

  12. Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Monica de, E-mail: desimone@tasc.infm.it [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Snidero, Elena [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy); Coreno, Marcello [CNR-IMIP, c/o Laboratorio TASC Area Science Park Basovizza, 34149 Trieste (Italy); Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Bongiorno, Gero [Fondazione Filarete, v.le Ortles 22/4, 20139 Milano (Italy); Giorgetti, Luca [Istituto Europeo di Oncologia, Dip. di Oncologia Sperimentale, Via Adamello 16, 20139, Milano (Italy); Amati, Matteo [Sincrotrone Trieste ScpA, Area Science Park Basovizza, 34149 Trieste (Italy); Cepek, Cinzia [CNR-IOM Laboratorio TASC, Area Science Park Basovizza, 34149 Trieste (Italy)

    2012-05-01

    We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a cluster-assembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti{sup 3+} is the first oxidation state observed, followed by Ti{sup 4+}, whereas Ti{sup 2+} is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.

  13. A two-color tunable infrared/vacuum ultraviolet spectrometer for high-resolution spectroscopy of molecules in molecular beams

    International Nuclear Information System (INIS)

    We describe here the key technical elements of a two-color tunable IR/VUV photoionization TOF mass spectrometer system which allows a wide-range of high-resolution experiments to be performed on a diverse range of cold molecules and clusters in a molecular beam. In particular we highlight the methods we have applied to provide efficient wavelength separation of the VUV radiation from the longer wavelength components used to generate it and discuss a number of systems that we have studied with the instrument which highlight its flexibility for use in the study of molecular spectroscopy.

  14. Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

    International Nuclear Information System (INIS)

    We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a cluster-assembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti3+ is the first oxidation state observed, followed by Ti4+, whereas Ti2+ is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.

  15. X-ray-induced beam damage observed during x-ray photoelectron spectroscopy (XPS) studies of palladium electrode ink materials

    International Nuclear Information System (INIS)

    The surface compositional characteristics of two palladium metal electrode inks, air-dried on barium titanate (BaTiO3) dielectric ceramic substrates, have been studied using x-ray photoelectron spectroscopy (XPS). It is found that exposure of the inks to the x-ray beam during the time of analysis required for data acquisition causes surface damage. Changes in the C 1s and O 1s regions in particular, which reflect modifications to the organic, polymeric binder materials present in the inks, have been integrated as a function of x-ray exposure time, incident photon energy and beam power levels. Additional complexity in the C 1s spectral envelope that cannot be explained in terms of the expected contributing organic functionalities is observed. This is explained in terms of a difference in charging effects experienced by adventitious carbon species and those intimately associated with palladium metal centres. The degree of damage induced by the x-ray beam under specific operating conditions has been compared also with that caused by exposure of the surfaces to an electron beam. Indications of the time scales and operating parameters for conducting XPS experiments on the unmodified surface, prior to surface degradation, are given. (author)

  16. Spectroscopy of 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) attached to rare gas samples: Clusters vs. bulk matrices. II. Fluorescence emission spectroscopy

    Science.gov (United States)

    Dvorak, Matthieu; Müller, Markus; Knoblauch, Tobias; Bünermann, Oliver; Rydlo, Alexandre; Minniberger, Stefan; Harbich, Wolfgang; Stienkemeier, Frank

    2012-10-01

    The interaction between 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) molecules and solid rare gas samples is studied by means of fluorescence emission spectroscopy. Laser-excited PTCDA-doped large argon, neon, and para-hydrogen clusters along with PTCDA embedded in helium nanodroplets are spectroscopically characterized with respect to line broadening and shifting. A fast non-radiative relaxation is observed before a radiative decay in the electronic ground state takes place. In comparison, fluorescence emission studies of PTCDA embedded in bulk neon and argon matrices result in much more complex spectral signatures characterized by a splitting of the different emission lines. These can be assigned to the appearance of site isomers of the surrounding matrix lattice structure.

  17. Relativistic Pair Beams from TeV Blazars: A Source of Reprocessed GeV Emission rather than Intergalactic Heating

    Science.gov (United States)

    Sironi, Lorenzo; Giannios, Dimitrios

    2014-05-01

    The interaction of TeV photons from blazars with the extragalactic background light produces a relativistic beam of electron-positron pairs streaming through the intergalactic medium (IGM). The fate of the beam energy is uncertain. By means of two- and three-dimensional particle-in-cell simulations, we study the nonlinear evolution of dilute ultra-relativistic pair beams propagating through the IGM. We explore a wide range of beam Lorentz factors γ b Gt 1 and beam-to-plasma density ratios α Lt 1, so that our results can be extrapolated to the extreme parameters of blazar-induced beams (γ b ~ 106 and α ~ 10-15, for powerful blazars). For cold beams, we show that the oblique instability governs the early stages of evolution, but its exponential growth terminates—due to self-heating of the beam in the transverse direction—when only a negligible fraction ~(α/γ b )1/3 ~ 10-7 of the beam energy has been transferred to the IGM plasma. Further relaxation of the beam proceeds through quasi-longitudinal modes, until the momentum dispersion in the direction of propagation saturates at Δp b, ∥/γ b mec ~ 0.2. This corresponds to a fraction ~10% of the beam energy—irrespective of γ b or α—being ultimately transferred to the IGM plasma (as compared to the heating efficiency of ~50% predicted by one-dimensional models, which cannot properly account for the transverse broadening of the beam). For the warm beams generated by TeV blazars, the development of the longitudinal relaxation is suppressed, since the initial dispersion in beam momentum is already Δp b0, ∥/γ b mec >~ 1. Here, the fraction of beam energy ultimately deposited into the IGM is only ~α γ b ~ 10-9. It follows that most of the beam energy is still available to power the GeV emission produced by inverse Compton up-scattering of the cosmic microwave background by the beam pairs.

  18. Development of a pulsed laser with emission at 1053 nm for Cavity Ring-Down Spectroscopy

    International Nuclear Information System (INIS)

    In this work, a pulsed and Q-switched laser resonator was developed using the double-beam mode-controlling technique. A Nd:LiYF4 crystal with 0,8mol% of doping concentration was used to generate a giant pulse with duration of 5,5 ns (FWHM), 1,2 mJ of energy and 220 kW peak power for the Cavity Ring-Down Spectroscopy (CRDS) technique. The CRDS technique is used to measure absorption spectra for gases, liquids and solids. With the CRDS technique it is possible to measure losses with high degree of accuracy, underscoring the sensitivity that is confirmed by the use of mirrors with high reflectivity. With this technique, the losses by reflection and scattering of transparent materials were evaluated. By calibrating the resonant cavity, it was possible to measure the losses in the samples with resolution of 0,045%, the maximum being reached by 0,18%. The calibration was possible because there was obtained to measure a decay time of approximately 20 μs with the empty cavity. Besides was obtained a method for determining the refractive index of transparent materials with accuracy of five decimals. (author)

  19. Reduction of organic solvent emission by industrial use of electron-beam curable coatings

    International Nuclear Information System (INIS)

    Most industrial finishing processes operate by the use of liquid organic coating materials drying by solvent evaporation and subsequent chemical crosslinking reactions, in many cases also releasing cleavage products. These organic emissions contribute to air pollution and therefore many countries have issued restrictions in order to protect the environment. Complementary to other modern methods for reducing this problem, radiation chemistry enables an approach by radical chain polymerization which can be induced by exposure to electron radiation. This procedure is known as electron-beam curing of coatings or the EBC process. It utilizes well-developed accelerator equipment with voltages of 150 to 400kV at a minimum energy consumption. There is no necessity to use irradiation facilities based on the decay of radioisotopes. Free radical polymerization requires unsaturated resins as pain binders and polymerizable liquid compounds (monomers) as reactive diluents. Their crosslinking yields a high molecular network, the coating, without any emission of organic solvents or cleavage products. Moreover, the radiochemical formation of the paint film occurs extremely rapidly. The technical application of EBC coatings began by coating automotive plastic parts; a little later the finishing of wood products gained more industrial use as a non-polluting and energy-saving coating technology. Application methods in coating plastic foils in combination with vacuum metallizing and the production of decorative laminating papers for furniture followed. In 1981 new EBC pilot lines were installed for curing top coats on PVC foil and also for the coating of prefinished steel wheels for automobiles. In comparison with conventional solvent-based methods the industrial EBC process results in a nearly complete reduction of organic solvent emission avoiding air pollution and saving valuable petrochemical raw materials. This paper reviews the development of EBC during the last decade. (author)

  20. CNS active target (CAT) for missing mass spectroscopy with intense beams

    International Nuclear Information System (INIS)

    A new gaseous active target based on a time projection chamber, named CAT, is introduced. The remarkable feature is a dual gain THGEM to decrease the effective gain for the beam particles while keeping a high enough effective gain for the recoil particles. The measured effective gain of low gain region was a factor of one hundred smaller than that of high gain region. This technique provides a wide dynamic range in order to detect both the beam and recoil particles at the same time even with a very high intensity beam of more than 105 Hz. (author)

  1. Atom-specific look at the surface chemical bond using x-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, A.; Wassdahl, N.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    CO and N{sub 2} adsorbed on the late transition metals have become prototype systems regarding the general understanding of molecular adsorption. It is in general assumed that the bonding of molecules to transition metals can be explained in terms of the interaction of the frontier HOMO and LUMO molecular orbitals with the d-orbitals. In such a picture the other molecular orbitals should remain essentially the same as in the free molecule. For the adsorption of the isoelectronic molecules CO and N{sub 2} this has led to the so called Blyholder model i.e., a synergetic {sigma} (HOMO) donor and {pi} (LUMO) backdonation bond. The authors results at the ALS show that such a picture is oversimplified. The direct observation and identification of the states related to the surface chemical bond is an experimental challenge. For noble and transition metal surfaces, the adsorption induced states overlap with the metal d valence band. Their signature is therefore often obscured by bulk substrate states. This complication has made it difficult for techniques such as photoemission and inverse photoemission to provide reliable information on the energy of chemisorption induced states and has left questions unanswered regarding the validity of the frontier orbitals concept. Here the authors show how x-ray emission spectroscopy (XES), in spite of its inherent bulk sensitivity, can be used to investigate adsorbed molecules. Due to the localization of the core-excited intermediate state, XE spectroscopy allows an atomic specific separation of the valence electronic states. Thus the molecular contributions to the surface measurements make it possible to determine the symmetry of the molecular states, i.e., the separation of {pi} and {sigma} type states. In all the authors can obtain an atomic view of the electronic states involved in the formation of the chemical bond to the surface.

  2. Diagnostics of the ITER neutral beam test facility

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualotto, R.; Serianni, G.; Agostini, M.; Brombin, M.; Dalla Palma, M.; Gazza, E.; Pomaro, N.; Rizzolo, A.; Spolaore, M.; Zaniol, B. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Sonato, P.; De Muri, M. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University (Italy); Croci, G. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); Gorini, G. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); CNISM, Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, Milano (Italy)

    2012-02-15

    The ITER heating neutral beam (HNB) injector, based on negative ions accelerated at 1 MV, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on the ITER HNB. The RF source, where the H{sup -}/D{sup -} production is enhanced by cesium evaporation, will be monitored with thermocouples, electrostatic probes, optical emission spectroscopy, cavity ring down, and laser absorption spectroscopy. The beam is analyzed by cooling water calorimetry, a short pulse instrumented calorimeter, beam emission spectroscopy, visible tomography, and neutron imaging. Design of the diagnostic systems is presented.

  3. Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 2: Wind propagation and emission rates

    OpenAIRE

    Harig, R.; Grutter, M.; Stremme, W.; Krueger, A.

    2013-01-01

    A technique for measuring two-dimensional (2-D) plumes of volcanic gases with thermal emission spectroscopy was described in Part 1 by Stremme et al. (2012a). In that paper the instrumental aspects as well as retrieval strategies for obtaining the slant column images of SO2 and SiF4, as well as animations of particular events observed at the Popocatépetl volcano, were presented. This work focuses on the procedures for determining the propagation speed of the gases and estimating an emiss...

  4. Terahertz Desorption Emission Spectroscopy (THz DES) – ‘ALMA in the Lab’

    Science.gov (United States)

    Emile Auriacombe, Olivier Bruno Jacques; Fraser, Helen; Ellison, Brian; Ioppolo, Sergio; Rea, Simon

    2016-06-01

    ALMA is revolutionising our scope to identify and locate molecules that have been desorbed from ices, particularly complex organic molecules (COMS), which provide a vital link between interstellar and prebiotic chemistry. Explaining the existence of these molecules in star-forming regions relies on an empirical understanding of the chemistry that underpins their formation:- do COMS form predominantly in the solid-phase and then desorb to the gas phase, or do only “smaller” species, radials or ions desorb and then undergo gas-phase chemical reactions to generate larger COMS?-are the rotational state populations in COMS only attributable to equilibrium chemistry, or could their formation mechanisms and desorption processes affect the rotational state occupancy of these molecules, thereby directly tying certain species to solid-state origins?We have developed a novel laboratory method - THz Desorption Emission Spectroscopy (THz-DES) that combines “traditional” laboratory astrophysics high-vacuum ice experiments with a sensitive high-spectral-resolution terahertz total-power heterodyne radiometer 1,2, partially mirroring the spectral range of ALMA band 7 (275– 373 GHz). Ices are grown in situ on a cold-plate, situated in a vacuum cell, then (thermally) desorbed. The sub-mm emission spectra of the resultant gas-phase molecules are detected as a function of time, temperature, or distance from the surface. Our first THz DES results will be shown for pure and binary ice systems including H2O, N2O and CH3OH. They show good correlation with established methods e.g. TPD, with the advantage of exploiting the molecular spectroscopy to unravel surface dynamics, state-occupancy, and unequivocal molecular identification, as well as concurrently measuring desorption barriers and molecular yields. We will extend our technique to a broader frequency range, enabling us to detect radical and ion desorption, to differentiate between A and E populations of CH3OH or ortho

  5. Multi-pulsed intense electron beam emission from velvet, carbon fibers, carbon nano-tubes and dispenser cathodes

    Science.gov (United States)

    Xia, Lian-Sheng; Yang, An-Min; Chen, Yi; Zhang, Huang; Liu, Xing-Guang; Li, Jin; Jiang, Xiao-Guo; Zhang, Kai-Zhi; Shi, Jin-Shui; Deng, Jian-Jun; Zhang, Lin-Wen

    2010-11-01

    The experimental results of studies of four kinds of cathode emitting intense electron beams are demonstrated under multi-pulsed mode based on an experimental setup including two multi-pulse high voltage sources. The tested cathodes include velvet, carbon fibers, carbon nano-tubes (CNTs) and dispenser cathodes. The results indicate that all four are able to emit multi-pulsed beams. For velvet, carbon fiber and CNTs, the electron induced cathode plasma emission may be the main process and this means that there are differences in beam parameters from pulse to pulse. For dispenser cathodes tested in the experiment, although there is a little difference from pulse to pulse for some reason, thermal-electric field emission may be the main process.

  6. Multi-pulsed intense electron beam emission from velvet, carbon fibers, carbon nano-tubes and dispenser cathodes

    International Nuclear Information System (INIS)

    The experimental results of studies of four kinds of cathode emitting intense electron beams are demonstrated under multi-pulsed mode based on an experimental setup including two multi-pulse high voltage sources. The tested cathodes include velvet, carbon fibers, carbon nano-tubes (CNTs) and dispenser cathodes. The results indicate that all four are able to emit multi-pulsed beams. For velvet, carbon fiber and CNTs, the electron induced cathode plasma emission may be the main process and this means that there are differences in beam parameters from pulse to pulse. For dispenser cathodes tested in the experiment, although there is a little difference from pulse to pulse for some reason, thermal-electric field emission may be the main process. (authors)

  7. Determination of total tin in canned food using inductively coupled plasma atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Perring, Loic; Basic-Dvorzak, Marija [Department of Quality and Safety Assurance, Nestle Research Centre, P.O. Box 44, Vers chez-les-Blanc, 1000, Lausanne (Switzerland)

    2002-09-01

    Tin is considered to be a priority contaminant by the Codex Alimentarius Commission. Tin can enter foods either from natural sources, environmental pollution, packaging material or pesticides. Higher concentrations are found in processed food and canned foods. Dissolution of the tinplate depends on the of food matrix, acidity, presence of oxidising reagents (anthocyanin, nitrate, iron and copper) presence of air (oxygen) in the headspace, time and storage temperature. To reduce corrosion and dissolution of tin, nowadays cans are usually lacquered, which gives a marked reduction of tin migration into the food product. Due to the lack of modern validated published methods for food products, an ICP-AES (Inductively coupled plasma-atomic emission spectroscopy) method has been developed and evaluated. This technique is available in many laboratories in the food industry and is more sensitive than atomic absorption. Conditions of sample preparation and spectroscopic parameters for tin measurement by axial ICP-AES were investigated for their ruggedness. Two methods of preparation involving high-pressure ashing or microwave digestion in volumetric flasks were evaluated. They gave complete recovery of tin with similar accuracy and precision. Recoveries of tin from spiked products with two levels of tin were in the range 99{+-}5%. Robust relative repeatabilities and intermediate reproducibilities were <5% for different food matrices containing >30 mg/kg of tin. Internal standard correction (indium or strontium) did not improve the method performance. Three emission lines for tin were tested (189.927, 283.998 and 235.485 nm) but only 189.927 nm was found to be robust enough with respect to interferences, especially at low tin concentrations. The LOQ (limit of quantification) was around 0.8 mg/kg at 189.927 nm. A survey of tin content in a range of canned foods is given. (orig.)

  8. Characterization of dissolved organic matter in fogwater by excitation-emission matrix fluorescence spectroscopy

    Science.gov (United States)

    Birdwell, J.E.; Valsaraj, K.T.

    2010-01-01

    Dissolved organic matter (DOM) present in fogwater samples collected in southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix fluorescence spectroscopy. The goal of the study was to illustrate the utility of fluorescence for obtaining information on the large fraction of organic carbon in fogwaters (typically >40% by weight) that defies characterization in terms of specific chemical compounds without the difficulty inherent in obtaining sufficient fogwater volume to isolate DOM for assessment using other spectroscopic and chemical analyses. Based on the findings of previous studies using other characterization methods, it was anticipated that the unidentified organic carbon fraction would have characteristic peaks associated with humic substances and fluorescent amino acids. Both humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices for the fogwater had similar values to those of soil and sediment porewater. Greater biological character was observed in samples with higher organic carbon concentrations. Fogwaters are shown to contain a mixture of terrestrially- and microbially-derived fluorescent organic material, which is expected to be derived from an array of different sources, such as suspended soil and dust particles, biogenic emissions and organic substances generated by atmospheric processes. The fluorescence results indicate that much of the unidentified organic carbon present in fogwater can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems, though it should be noted that fluorescent signatures representative of DOM produced by atmospheric processing of organic aerosols may be contributing to or masked by humic-like fluorophores. ?? 2010.

  9. Effects of a Relativistic Electron Beam Interaction with the Upper Atmosphere: Ionization, X-Rays, and Optical Emissions

    Science.gov (United States)

    Marshall, R. A.; Nicolls, M. J.; Sanchez, E. R.; Lehtinen, N. G.; Neilson, J.

    2014-12-01

    An artificial beam of relativistic (0.5--10 MeV) electrons has been proposed as an active experiment in the ionosphere and magnetosphere, with applications to magnetic field-line tracing, studies of wave-particle interactions, and beam-atmosphere interactions. The beam-atmosphere interaction, while a scientific endeavor of its own, also provides key diagnostics for other experiments. We present results of Monte Carlo simulations of the interaction of a beam of relativistic electrons with the upper atmosphere as they are injected downwards from a notional high altitude (thermospheric / ionospheric) injection platform. The beam parameters, defined by realistic parameters of a compact linear accelerator, are used to create a distribution of thousands of electrons. Each electron is injected downwards from 300 km altitude towards the dense atmosphere, where it undergoes elastic and inelastic collisions, leading to secondary ionization, optical emissions, and X-rays via bremsstrahlung. Here we describe the Monte Carlo model and present calculations of diagnostic outputs, including optical emissions, X-ray fluxes, secondary ionization, and backscattered energetic electron fluxes. Optical emissions are propagated to the ground through the lower atmosphere, including the effects of atmospheric absorption and scattering, to estimate the brightness of the emission column for a given beam current and energy. Similarly, X-ray fluxes are propagated to hypothetical detectors on balloons and satellites, taking into account Compton scattering and photoabsorption. Secondary ionization is used to estimate the radar signal returns from various ground-based radar facilities. Finally, simulated backscattered electron fluxes are measured at the injection location. The simulation results show that for realizable accelerator parameters, each of these diagnostics should be readily detectable by appropriate instruments.

  10. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marcak, Adrian; Corbella, Carles, E-mail: carles.corbella@rub.de; Keudell, Achim von [Research Group Reactive Plasmas, Ruhr-University Bochum, 44801 Bochum (Germany); Arcos, Teresa de los [Technical and Macromolecular Chemistry, Paderborn University, 33098 Paderborn (Germany)

    2015-10-15

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  11. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    International Nuclear Information System (INIS)

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications

  12. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Science.gov (United States)

    Marcak, Adrian; Corbella, Carles; de los Arcos, Teresa; von Keudell, Achim

    2015-10-01

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  13. High-power continuous-wave tunable 544- and 272-nm beams based on a diode-oscillator fiber-amplifier for calcium spectroscopy

    Science.gov (United States)

    Ko, Kwang-Hoon; Kim, Yonghee; Park, Hyunmin; Cha, Yong-Ho; Kim, Taek-Soo; Lee, Lim; Lim, Gwon; Han, Jaemin; Ko, Kwang-Hee; Jeong, Do-Young

    2015-08-01

    Continuous-wave single-frequency tunable 544- and 272-nm beams have been demonstrated by the second- and fourth-harmonic conversions of a 1088-nm fundamental beam from a diode-oscillator fiber-amplifier. The single-pass second-harmonic generation with a MgO-doped periodically poled stoichiometric LiTaO3 crystal and the external-cavity frequency-doubling technique with a bulk BBO crystal were employed to achieve an approximately 6-W 544-nm beam and a 1.5-W 272-nm beam, respectively. We characterized the second- and fourth-harmonic generations and discussed their applications to calcium spectroscopy.

  14. Holographic interferometry as electrochemical emission spectroscopy of carbon steel in seawater with low concentration of RA-41 corrosion inhibitor

    International Nuclear Information System (INIS)

    In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the number of the fringe evolutions during the corrosion test of carbon steel in blank seawater and with seawater with different concentrations of a corrosion inhibitor. In other words, the anodic dissolution behaviors (corrosion) of the carbon steel were determined simultaneously by holographic interferometry, an electromagnetic method, and by the electrochemical impedance (EI) spectroscopy, an electronic method. So, the abrupt rate change of the number of the fringe evolutions during corrosion test (EI) spectroscopy, of the carbon steel is called electrochemical emission spectroscopy. The corrosion process of the steel samples was carried out in blank seawater and seawater with different concentrations, 5-20 ppm, of RA-41 corrosion inhibitor using the EI spectroscopy method, at room temperature. The electrochemical emission spectra of the carbon steel in different solutions represent a detailed picture of the rate change of the anodic dissolution of the steel throughout the corrosion processes. Furthermore, the optical interferometry data of the carbon steel were compared to the data, which were obtained from the EI spectroscopy. Consequently, holographic interferometric is found very useful for monitoring the anodic dissolution behaviors of metals, in which the number of the fringe evolutions of the steel samples can be determined in situ. (Author)

  15. A single-beam titration method for the quantification of open-path Fourier transform infrared spectroscopy

    Science.gov (United States)

    Sung, Lung-Yu; Lu, Chia-Jung

    2014-09-01

    This study introduced a quantitative method that can be used to measure the concentration of analytes directly from a single-beam spectrum of open-path Fourier Transform Infrared Spectroscopy (OP-FTIR). The peak shapes of the analytes in a single-beam spectrum were gradually canceled (i.e., "titrated") by dividing an aliquot of a standard transmittance spectrum with a known concentration, and the sum of the squared differential synthetic spectrum was calculated as an indicator for the end point of this titration. The quantity of a standard transmittance spectrum that is needed to reach the end point can be used to calculate the concentrations of the analytes. A NIST traceable gas standard containing six known compounds was used to compare the quantitative accuracy of both this titration method and that of a classic least square (CLS) using a closed-cell FTIR spectrum. The continuous FTIR analysis of industrial exhausting stack showed that concentration trends were consistent between the CLS and titration methods. The titration method allowed the quantification to be performed without the need of a clean single-beam background spectrum, which was beneficial for the field measurement of OP-FTIR. Persistent constituents of the atmosphere, such as NH3, CH4 and CO, were successfully quantified using the single-beam titration method with OP-FTIR data that is normally inaccurate when using the CLS method due to the lack of a suitable background spectrum. Also, the synthetic spectrum at the titration end point contained virtually no peaks of analytes, but it did contain the remaining information needed to provide an alternative means of obtaining an ideal single-beam background for OP-FTIR.

  16. Experiments and FLUKA simulations of $^{12}C$ and $^{16}O$ beams for therapy monitoring by means of in-beam Positron Emission Tomography

    CERN Document Server

    Sommerer,; Ferrari, A

    2007-01-01

    Since 1997 at the experimental C-12 ion therapy facility at Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt, Germany, more than 350 patients have been treated. The therapy is monitored with a dedicated positron emission tomograph, fully integrated into the treatment site. The measured beta+-activity arises from inelastic nuclear interactions between the beam particles an the nuclei of the patients tissue. Because the monitoring is done during the irradiation the method is called in-beam PET. The underlying principle of this monitoring is a comparison between the measured activity and a simulated one. The simulations are presently done by the PETSIM code which is dedicated to C-12 beams. In future ion therapy centers like the Heidelberger Ionenstrahl Therapiezentrum (HIT), Heidelberg, Germany, besides C-12 also proton, $^3$He and O-16 beams will be used for treatment and the therapy will be monitored by means of in-beam PET. Because PETSIM is not extendable to other ions in an easy way, a code capable ...

  17. Speciation and transformations of cobalt(II) in bacterial cells using emission (57Co) Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Complete text of publication follows. The 57Co emission variant of Moessbauer spectroscopy (EMS), despite its solitary applications in biology owing to intrinsic methodological difficulties (Yu.D. Perfiliev, A.A. Kamnev, Moessbauer Effect Ref. and Data J., 30 (2007) 121-122; A.A. Kamnev, J. Mol. Struct., 744-747 (2005) 161-167), is highly sensitive and informative. The parameters of 57Co emission spectra provide chemical speciation data for the 57Co cation (chemical state, coordination environment and symmetry, etc.), as well as quantitative information on its distribution between different cation-binding sites in complicated biosystems (A.A. Kamnev, in 'Metal Ions in Biology and Medicine', Vol. 10, John Libbey Eurotext, Paris (2008), pp. 522-527). 57Co EMS can be successfully applied for monitoring 57Co2+ interactions with microbial cells, including its metabolic transformations (A.A. Kamnev et al., Anal. Chim. Acta, 573-574 (2006) 445-452). Comparative studies in rapidly frozen aqueous suspensions of live and dead cells of the ubiquitous phytostimulating soil bacterium Azospirillum brasilense have shown similarities in the chemical species formed upon purely chemical interaction of 57Co2+ traces with dead cell biomass and those formed upon primary rapid steps (2 min) of 57Co2+ sorption by the surface of live cells. For live cells, however, the parameters of 57Co emission spectra were found to change within an hour, which reflected ongoing metabolic transformations of the cation. The data obtained are in good agreement with the recently discovered involvement of Co2+ in reactions with labile [Fe-S] clusters during their de novo biosynthesis or repair in E. coli (C. Ranquet et al., J. Biol. Chem., 282 (2007) 30442-30451), presenting the molecular basis for Co2+ toxicity, besides Co2+-induced oxidative stress. The results obtained show that 57Co EMS can provide unique information both for speciation bioanalysis and for the monitoring of radionuclide bioleaching and

  18. Optical Emission Spectroscopy in PECVD Helps Modulate Key Features in Biofunctional Coatings for Medical Implants

    Science.gov (United States)

    Santos, Miguel; Michael, Praveesuda; Filipe, Elysse; Wise, Steven; Bilek, Marcela; University of Sydney Collaboration

    2015-09-01

    We explore the use of optical emission spectroscopy (OES) diagnostic tools as a process feedback control strategy in plasma-assisted deposition of biofunctional coatings. Hydrogenated carbon nitride coatings are deposited on medical-grade metallic substrates using radio-frequency (rf) discharges sustained in C2H2/N2/Ar gaseous mixtures. The discharge is generated by capacitively coupling the rf power (supplied at f = 13.56 MHz) to the plasma and the substrates are electrically biased using a pulse generator to provide microsecond square profiled pulses at voltages in the range |Vbias| = 250 V - 1000 V. Nitrogen content and CN bonding configurations in the coatings follow similar trends to those of CN radicals and nitrogen molecular ions in the discharge. OES is used as a non-intrusive diagnostic technique to identify a suitable window of process parameters and ultimately achieve biofunctional interfaces compatible with current clinical demands. Importantly, we demonstrate that key features of the coatings can be modulated and made suitable for blood and/or tissue contacting medical implants, such as coronary stents and orthopaedic implants. The coatings are mechanically robust, inherently non-thrombogenic and can be readily modified, enabling an easy functionalization through the immobilization of biological molecules in a bioactive conformation.

  19. The emission spectroscopy of the B2Σ- -X2 Π system of CD

    Science.gov (United States)

    Szajna, W.; Zachwieja, M.; Hakalla, R.

    2016-06-01

    The visible spectrum of CD has been investigated at high resolution between 24,500 and 27,500 cm-1 using a high accuracy dispersive optical spectroscopy technique. The CD molecules were produced and excited in a stainless steel hollow-cathode lamp with two anodes and filled with a mixture of He buffer gas and CD4. The emission from the discharge was observed with a plane grating spectrograph and recorded by a photomultiplier tube. The 0-0, 1-0 and 1-1 bands of the B2Σ- -X2 Π transition have been registered and measured, while 2-0 and 2-1 absorption bands (Herzberg and Johns, 1969) have been reanalyzed. The current data were elaborated with help of recent X2 Π ground state parameters reported by Zachwieja et al. (2012) from investigation of the A2 Δ -X2 Π transition. This way, the improved spectroscopic constants for the B2Σ- state of CD have been provided as follows: νe = 26,050.787 (11) cm-1, ωe = 1653.019 (25) cm-1, ωexe = 123.899 (12) cm-1, Be = 7.08296 (32) cm-1, αe = 0.30741 (84) cm-1, and γe = - 0.10727 (42) cm-1.

  20. PPAK Wide-field Integral Field Spectroscopy of NGC 628: II. Emission line abundance analysis

    CERN Document Server

    Rosales-Ortega, F F; Kennicutt, R C; Sánchez, S F

    2011-01-01

    In this second paper of the series, we present the 2-dimensional (2D) emission line abundance analysis of NGC 628, the largest object within the PPAK Integral Field Spectroscopy (IFS) Nearby Galaxies Survey: PINGS. We introduce the methodology applied to the 2D IFS data in order to extract and deal with large spectral samples, from which a 2D abundance analysis can be later performed. We obtain the most complete and reliable abundance gradient of the galaxy up-to-date, by using the largest number of spectroscopic points sampled in the galaxy, and by comparing the statistical significance of different strong-line metallicity indicators. We find features not previously reported for this galaxy that imply a multi-modality of the abundance gradient consistent with a nearly flat-distribution in the innermost regions of the galaxy, a steep negative gradient along the disc and a shallow gradient or nearly-constant metallicity beyond the optical edge of the galaxy. The N/O ratio seems to follow the same radial behavi...

  1. Investigation of the Ionic Hydration in Aqueous Salt Solutions by Soft X-ray Emission Spectroscopy.

    Science.gov (United States)

    Jeyachandran, Y L; Meyer, F; Benkert, A; Bär, M; Blum, M; Yang, W; Reinert, F; Heske, C; Weinhardt, L; Zharnikov, M

    2016-08-11

    Understanding the molecular structure of the hydration shells and their impact on the hydrogen bond (HB) network of water in aqueous salt solutions is a fundamentally important and technically relevant question. In the present work, such hydration effects were studied for a series of representative salt solutions (NaCl, KCl, CaCl2, MgCl2, and KBr) by soft X-ray emission spectroscopy (XES) and resonant inelastic soft X-ray scattering (RIXS). The oxygen K-edge XES spectra could be described with three components, attributed to initial state HB configurations in pure water, water molecules that have undergone an ultrafast dissociation initiated by the X-ray excitation, and water molecules in contact with salt ions. The behavior of the individual components, as well as the spectral shape of the latter component, has been analyzed in detail. In view of the role of ions in such effects as protein denaturation (i.e., the Hofmeister series), we discuss the ion-specific nature of the hydration shells and find that the results point to a predominant role of anions as compared to cations. Furthermore, we observe a concentration-dependent suppression of ultrafast dissociation in all salt solutions, associated with a significant distortion of intact HB configurations of water molecules facilitating such a dissociation. PMID:27442708

  2. Plasma Wind Tunnel Investigation of European Ablators in Nitrogen/Methane Using Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ricarda Wernitz

    2013-01-01

    Full Text Available For atmospheric reentries at high enthalpies ablative heat shield materials are used, such as those for probes entering the atmosphere of Saturn’s moon Titan, such as Cassini-Huygens in December, 2004. The characterization of such materials in a nitrogen/methane atmosphere is of interest. A European ablative material, AQ60, has been investigated in plasma wind tunnel tests at the IRS plasma wind tunnel PWK1 using the magnetoplasma dynamic generator RD5 as plasma source in a nitrogen/methane atmosphere. The dimensions of the samples are 45 mm in length with a diameter of 39 mm. The actual ablator has a thickness of 40 mm. The ablator is mounted on an aluminium substructure. The experiments were conducted at two different heat flux regimes, 1.4 MW/m2 and 0.3 MW/m2. In this paper, results of emission spectroscopy at these plasma conditions in terms of plasma species’ temperatures will be presented, including the investigation of the free-stream species, N2 and N2+, and the major erosion product C2, at a wavelength range around 500 nm–600 nm.

  3. Trace cobalt speciation in bacteria and at enzymic active sites using emission Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kamnev, A.A.; Antonyuk, L.P.; Smirnova, V.E.; Serebrennikova, O.B. [Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Saratov (Russian Federation); Kulikov, L.A.; Perfiliev, Yu.D. [Laboratory of Nuclear Chemistry Techniques, Department of Radiochemistry, Faculty of Chemistry, Moscow State University (Russian Federation)

    2002-02-01

    {sup 57}Co emission Moessbauer spectroscopy (EMS) allows the chemical state of cobalt, as influenced by its coordination environment, to be monitored in biological samples at its physiological (trace) concentrations. To draw attention to EMS as a valuable tool for speciation of cobalt in biocomplexes, the process of cobalt(II) metabolism in cells of the plant growth-promoting rhizobacterium Azospirillum brasilense Sp245 was investigated using EMS of {sup 57}Co{sup II}-doped bacterial cells. EMS measurements also showed {sup 57}Co{sup II}-activated glutamine synthetase (GS, a key enzyme of nitrogen metabolism, isolated from this bacterium) to have two different cobalt(II) forms at its active sites, in agreement with data available on other bacterial GSs. Chemical after-effects following electron capture by the nucleus of the parent {sup 57}Co{sup II} during the {sup 57}Co{yields}{sup 57}Fe transition, which contribute to the formation of a stabilised daughter {sup 57}Fe{sup III} component along with the nucleogenic {sup 57}Fe{sup II} forms, are also briefly considered. (orig.)

  4. Observation of iron spin-states using tabletop x-ray emission spectroscopy and microcalorimeter sensors

    Science.gov (United States)

    Joe, Y. I.; O'Neil, G. C.; Miaja-Avila, L.; Fowler, J. W.; Jimenez, R.; Silverman, K. L.; Swetz, D. S.; Ullom, J. N.

    2016-01-01

    X-ray emission spectroscopy (XES) is a powerful probe of the electronic and chemical state of elemental species embedded within complex compounds. X-ray sensors that combine high resolving power and high collecting efficiency are desirable for photon-starved XES experiments such as measurements of dilute, gaseous, and radiation-sensitive samples, time-resolved measurements, and in-laboratory XES. To assess whether arrays of cryogenic microcalorimeters will be useful in photon-starved XES scenarios, we demonstrate that these emerging energy-dispersive sensors can detect the spin-state of 3d electrons of iron in two different compounds, Fe2O3 and FeS2. The measurements were conducted with a picosecond pulsed laser-driven plasma as the exciting x-ray source. The use of this tabletop source suggests that time-resolved in-laboratory XES will be possible in the future. We also present simulations of {{K}}α and {{K}}β spectra that reveal the spin-state sensitivity of different combinations of sensor resolution and accumulated counts. These simulations predict that our current experimental apparatus can perform time-resolved XES measurements on some samples with a measurement time of a few 10 s of hours per time delay.

  5. Diagnostics of helium plasma by collisional-radiative modeling and optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wonwook; Kwon, Duck-Hee [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    Optical diagnostics for the electron temperature (T{sub e}) and the electron density (n{sub e}) of fusion plasma is important for understanding and controlling the edge and the divertor plasmas in tokamak. Since the line intensity ratio method using the collisional-radiative modeling and OES (optical emission spectroscopy) is simple and does not disturb the plasma, many fusion devices with TEXTOR, JET, JT-60U, LHD, and so on, have employed the line intensity ratio method as a basic diagnostic tool for neutral helium (He I). The accuracy of the line intensity ratio method depends on the reliability of the cross sections and rate coefficients. We performed state-of-the-art R-matrix calculations including couplings up to n=7 states and the distorted wave (DW) calculations for the electron-impact excitation (EIE) cross sections of He I using the flexible atomic code (FAC). The collisional-radiative model for He I was constructed using the calculated the cross sections. The helium collisional-radiative model for He I was constructed to diagnose the electron temperature and the electron density of the plasma. The electron temperature and density were determined by using the line intensity ratio method.

  6. Gas temperature determination in microwave discharges at atmospheric pressure by using different Optical Emission Spectroscopy techniques

    International Nuclear Information System (INIS)

    Non-thermal plasmas sustained at atmospheric pressure are considered as a very promising technology for different purposes, in which the knowledge of the gas temperature is an important issue. In this paper, the gas temperatures of different argon microwave (2.45 GHz) plasma torches were determined by using different Optical Emission Spectroscopy techniques. Thus, they were estimated through the analysis of N2+(B-X) and OH(A-X) molecular spectra. On the other hand, a method based on the measurement of the van der Waals broadening of 588.99 nm Na I line was employed, and the temperatures obtained from it were compared to the rotational temperatures derived from N2+(B-X) and OH(A-X) rotational bands. A reasonable good agreement was found between the values of temperatures obtained by using the 588.99 nm Na I line and those obtained from N2+ rotational band. - Highlights: • We measured the gas temperatures of different 2.45 GHz plasmas. • We obtained the gas temperature from N2 and OH molecular spectra. • We compared with an alternative method using 588.99 and 589.59 nm Na I lines. • A very good agreement between the values of Tgas obtained was found. • Τhe alternative method could be very helpful in plasmas containing nitrogen

  7. Accurate measurement of the HI column density from HI 21cm absorption-emission spectroscopy

    CERN Document Server

    Chengalur, Jayaram N; Roy, Nirupam

    2013-01-01

    We present a detailed study of an estimator of the HI column density, based on a combination of HI 21cm absorption and HI 21cm emission spectroscopy. This "isothermal" estimate is given by $N_{\\rm HI,ISO} = 1.823 \\times 10^{18} \\int \\left[ \\tau_{\\rm tot} \\times {\\rm T_B} \\right] / \\left[ 1 - e^{-\\tau_{\\rm tot}} \\right] {\\rm dV}$, where $\\tau_{\\rm tot}$ is the total HI 21cm optical depth along the sightline and ${\\rm T_B}$ is the measured brightness temperature. We have used a Monte Carlo simulation to quantify the accuracy of the isothermal estimate by comparing the derived $N_{\\rm HI,ISO}$ with the true HI column density $N_{\\rm HI}$. The simulation was carried out for a wide range of sightlines, including gas in different temperature phases and random locations along the path. We find that the results are statistically insensitive to the assumed gas temperature distribution and the positions of different phases along the line of sight. The median value of the ratio of the true H{\\sc i} column density to the...

  8. Polarization spectroscopy of tokamak plasmas

    International Nuclear Information System (INIS)

    Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs

  9. Electrostatically focused addressable field emission array chips (AFEA's) for high-speed massively parallel maskless digital E-beam direct write lithography and scanning electron microscopy

    Science.gov (United States)

    Thomas, Clarence E.; Baylor, Larry R.; Voelkl, Edgar; Simpson, Michael L.; Paulus, Michael J.; Lowndes, Douglas H.; Whealton, John H.; Whitson, John C.; Wilgen, John B.

    2002-12-24

    Systems and methods are described for addressable field emission array (AFEA) chips. A method of operating an addressable field-emission array, includes: generating a plurality of electron beams from a pluralitly of emitters that compose the addressable field-emission array; and focusing at least one of the plurality of electron beams with an on-chip electrostatic focusing stack. The systems and methods provide advantages including the avoidance of space-charge blow-up.

  10. A single-beam titration method for the quantification of open-path Fourier transform infrared spectroscopy

    International Nuclear Information System (INIS)

    This study introduced a quantitative method that can be used to measure the concentration of analytes directly from a single-beam spectrum of open-path Fourier Transform Infrared Spectroscopy (OP-FTIR). The peak shapes of the analytes in a single-beam spectrum were gradually canceled (i.e., “titrated”) by dividing an aliquot of a standard transmittance spectrum with a known concentration, and the sum of the squared differential synthetic spectrum was calculated as an indicator for the end point of this titration. The quantity of a standard transmittance spectrum that is needed to reach the end point can be used to calculate the concentrations of the analytes. A NIST traceable gas standard containing six known compounds was used to compare the quantitative accuracy of both this titration method and that of a classic least square (CLS) using a closed-cell FTIR spectrum. The continuous FTIR analysis of industrial exhausting stack showed that concentration trends were consistent between the CLS and titration methods. The titration method allowed the quantification to be performed without the need of a clean single-beam background spectrum, which was beneficial for the field measurement of OP-FTIR. Persistent constituents of the atmosphere, such as NH3, CH4 and CO, were successfully quantified using the single-beam titration method with OP-FTIR data that is normally inaccurate when using the CLS method due to the lack of a suitable background spectrum. Also, the synthetic spectrum at the titration end point contained virtually no peaks of analytes, but it did contain the remaining information needed to provide an alternative means of obtaining an ideal single-beam background for OP-FTIR. - Highlights: • Establish single beam titration quantification method for OP-FTIR. • Define the indicator for the end-point of spectrum titration. • An ideal background spectrum can be obtained using single beam titration. • Compare the quantification between titration and

  11. High temperature and high resolution uv photoelectron spectroscopy using supersonic molecular beams

    International Nuclear Information System (INIS)

    A high temperature molecular beam source with electron bombardment heating has been built for high resolution photoelectron spectroscopic studies of high temperature species and clusters. This source has the advantages of: producing an intense, continuous, seeded molecular beam, eliminating the interference of the heating mechanism from the photoelectron measurement. Coupling the source with our hemispherical electron energy analyzer, we can obtain very high resolution HeIα (584 angstrom) photoelectron spectra of high temperature species. Vibrationally-resolved photoelectron spectra of PbSe, As2, As4, and ZnCl2 are shown to demonstrate the performance of the new source. 25 refs., 8 figs., 1 tab

  12. Nanoparticle Enhanced Laser Induced Breakdown Spectroscopy: Effect of nanoparticles deposited on sample surface on laser ablation and plasma emission

    International Nuclear Information System (INIS)

    In this paper the use of metallic nanoparticles (NPs) for improving Laser Induced Breakdown Spectroscopy (LIBS) is discussed. In the case of conductors an emission signal enhancement up to 1–2 orders of magnitude was obtained depositing NPs on the sample surface by drying a micro-drop of colloidal solution. The basic mechanisms of Nanoparticle Enhanced LIBS (NELIBS) were studied and the main causes of this significantly large enhancement were found to be related to the effect of NPs on the laser ablation process, in terms of a faster and more efficient production of seed electrons with respect to conventional LIBS. The characteristics of NELIBS-produced plasma were investigated by emission spectroscopy and spectrally resolved images. In spite of similar plasma parameters, the NELIBS plasma was found to have larger emission volume and longer persistence than the LIBS one. A method to determine NP concentration and size was also proposed, which involved depositing NPs on non-interacting substrates, and proved the feasibility of LIBS as a fast detection tool for a preliminary characterization of NPs. - Highlights: • Effect of NPs on sample surface enables instantaneous field emission. • More efficient ablation • LIBS emission enhancement up to 1–2 orders of magnitude • Possibility of NP characterization in terms of concentration and size

  13. A Chemical Detector for Gas Chromatography Using Pulsed Discharge Emission Spectroscopy on a Microchip

    Science.gov (United States)

    Luo, X.; Zhu, W.; Mitra, B.; Liu, J.; Liu, T.; Fan, X.; Gianchandani, Y.

    2011-12-01

    There is increasing interest in miniaturized systems for chemical analysis in harsh environments. Chemical detection by emission spectroscopy of on-chip microdischarges [1-3] can be performed at >200°C [4], suggesting utility inspace exploration, volcanic monitoring, and oil well monitoring. This abstract describes the first use of pulsed microdischarge spectroscopy for gas chromatography (GC).This effort supports NASA interests in monitoring closed-loop life support systems for spacecraft. The microdischarge occurs on a 1cm2 glass chip (Fig. 1a), with thin-film Ni electrodes separated by 160μm. A glass lid with a grooved gas-flow channel, and inlet/outlet capillary tubes are epoxy-sealed to the chip. Located downstream of the 1.7m-long, RTX-1-coated, GC separation column, the microdischarge chip is read by a spectrometer. In a typical experiment (Fig. 1b), a mixture of acetone 3.6μg, 1-hexanol 2.8μg and nitrobenzene 3.0μg, is injected, with He carrier gas at 1.56sccm, through the GC. Acetone elutes quickly while nitrobenzene is slower. Microdischarges are triggered at 0.5Hz for 6 min., and 0.04Hz thereafter. Each microdischarge consumes ≈8mJ; the average power is ≈1.14mW. The spectrum (Fig. 1b, inset) shows that the 388nm peak, representing CN/CH fragments [5], is enhanced by carbon compounds. Its strength relative to the 588nm peak of He provides a chromatogram. Fig. 1b also shows a benchmark result from a commercial flame ionization detector (FID). The differences in elution time are attributed to differences in the gas flow paths for the two detectors [1]. REFERENCES [1] Eijkel et al, Anal. Chem, 2000 [2] Mitra et al, IEEE Trans Plasma Sci, 2008 [3] Mitra et al, IEEE Sensors, 2008 [4] Wright et al, APL, 2009 [5] Pearse et al, The Identification of Molecular Spectra, 1963

  14. Electrochemical emission and impedance spectroscopies of passive iron and carbon steel

    Science.gov (United States)

    Liu, Jun

    A high fidelity in situ technique for measuring electrochemical noise data on carbon steel in alkaline solutions, referred to as Electrochemical Emission Spectroscopy (EES), or Electrochemical Noise Measurement (ENM), has been developed in this thesis as a means of monitoring general corrosion and pitting corrosion on carbon steel in simulated DOE nuclear waste storage systems and to develop a better understanding of the corrosion processes of carbon steel in these environments. The data acquisition system is essential to the accuracy of voltage and current measurements and the validity of experimental data for further analysis. Time and frequency domain analyses display different characteristics for general corrosion and pitting corrosion. DOE raw noise data analysis shows that the penetration corrosion rate in liquid/sludge phases is in the order of 10-2--10-3 mm/year for the carbon steel-lined tanks in the DOE waste environments. In addition, good correlation has been observed between EES and traditional Linear Polarization Resistance (LPR) method in detecting the corrosion rates of carbon steel. The passive state on iron in EDTA (ethylene diammine tetra acetic acid, disodium salt, C10H14N2Na2O 8)-containing borate buffer solutions of pH ranging from 8.15 to 12.87 at ambient temperature has been explored using Electrochemical Impedance Spectroscopy (EIS), another powerful in situ electrochemical method for investigating steady-state electrochemical and corrosion systems. It has been found that frequency sweep range, perturbation voltage amplitude, solution pH, and film formation voltage are important factors to influence the impedance of passive iron. The steady-state passive films formed on iron have been shown to satisfy the conditions of linearity, causality, stability and finiteness, on the basis of the good agreement observed between the experimental impedance data and the Kramers-Kronig transforms calculated data over most of the frequency range employed

  15. Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

  16. Investigations of the cathode region of an argon arc plasma by degenerate four-wave mixing laser spectroscopy and optical emission spectroscopy

    International Nuclear Information System (INIS)

    Degenerate four-wave mixing (DFWM) laser spectroscopy was used in local studies of atmospheric pressure argon plasma generated in a free-burning arc. The results of plasma diagnostics using the DFWM method were compared to the results obtained with optical emission measurements. In the cathode region of the arc the maxima of both the DFWM signal and the emission coefficient for the 696.5 nm Ar I line depend on the distance from the cathode tip. This effect proves the departure of the plasma state from local thermal equilibrium (LTE) as it has been reported by many authors. On the other hand the Stark shifts of the 696.5 nm Ar I line determined by the DFWM method in relation to plasma diagnostic results show no deviations from LTE on the arc axis down to 1.0 mm from the cathode tip

  17. Tomography feasibility study on the optical emission spectroscopy diagnostic for the negative ion source of the ELISE test facility

    International Nuclear Information System (INIS)

    A feasibility study of a spectroscopic tomographic diagnostic for the emissivity reconstruction of the plasma parameters in the large negative ion source of the test facility ELISE is described. Tomographic tools are developed to be applied to the measurements of the ELISE optical emission spectroscopy (OES) diagnostic, in order to reconstruct the emissivity distribution from hydrogen (or deuterium) plasma close to the plasma grid, where negative ions are produced and extracted to be accelerated. Various emissivity phantoms, both symmetric and asymmetric, reproducing different plasma experimental conditions have been simulated to test the tomographic algorithm. The simultaneous algebraic reconstruction technique has been applied, accounting for the OES geometrical layout together with a suitable pixel representation. Even with a limited number of 14 lines of sight (LoSs), the plasma emissivity distribution expected on the ELISE source can be successfully reconstructed. In particular, asymmetries in the emissivity pattern can be detected and reproduced with low errors. A systematic investigation of different geometrical layouts of the LoSs as well as of the pixel arrangements has been carried out, and a final configuration has been identified. Noise on the simulated experimental spectroscopic measurements has been tested, confirming the reliability of the adopted tomographic tools for the plasma emissivity reconstructions of the source plasma in ELISE with the actual OES diagnostic system. (paper)

  18. Actinometric Investigation of In-Situ Optical Emission Spectroscopy Data in SiO2 Plasma Etch

    OpenAIRE

    Boom Soo Kim; Sang Jeen Hong

    2012-01-01

    Optical emission spectroscopy (OES) is often used for real-time analysis of the plasma processes. OES has beensuggested as a primary plasma process monitoring tool. It has the advantage of non-invasive in-situ monitoringcapability but selecting the proper wavelengths for the analysis of OES data generally relies on empirically establishedmethods. In this paper, we propose a practical method for the selection of OES wavelength peaks for the analysisof plasma etch process and this is done by in...

  19. Soft X-ray emission spectroscopy of liquids and lithium battery materials

    International Nuclear Information System (INIS)

    Lithium ion insertion into electrode materials is commonly used in rechargeable battery technology. The insertion implies changes in both the crystal structure and the electronic structure of the electrode material. Side-reactions may occur on the surface of the electrode which is exposed to the electrolyte and form a solid electrolyte interface (SEI). The understanding of these processes is of great importance for improving battery performance. The chemical and physical properties of water and alcohols are complicated by the presence of strong hydrogen bonding. Various experimental techniques have been used to study geometrical structures and different models have been proposed to view the details of how these liquids are geometrically organized by hydrogen bonding. However, very little is known about the electronic structure of these liquids, mainly due to the lack of suitable experimental tools. In this thesis examples of studies of lithium battery electrodes and liquid systems using soft x-ray emission spectroscopy will be presented. Monochromatized synchrotron radiation has been used to accomplish selective excitation, in terms of energy and polarization. The electronic structure of graphite electrodes has been studied, before and after lithium intercalation. Changes in the electronic structure upon lithiation due to transfer of electrons into the graphite π-bands have been observed. Transfer of electrons in to the 3d states of transition metal oxides upon lithiation have been studied, through low energy excitations as dd- and charge transfer-excitations. A SEI was detected on cycled graphite electrodes. By the use of selective excitation different carbon sites were probed in the SEI. The local electronic structure of water, methanol and mixtures of the two have been examined using a special liquid cell, to separate the liquid from the vacuum in the experimental chamber. Results from the study of liquid water showed a strong influence on the 3a1 molecular

  20. Characterization of a direct dc-excited discharge in water by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, Peter; Leys, Christophe [Department of Applied Physics, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent (Belgium); Schram, Daan [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Gonzalez, Manuel A [Departamento de Fisica Aplicada, Universidad de Valladolid, 47011 Valladolid (Spain); Rego, Robby [Flemish Institute of Technological Research, VITO Materials, Boeretang 200, B-2400 Mol (Belgium); Kong, Michael G [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)], E-mail: peter.bruggeman@ugent.be

    2009-05-01

    Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 {mu}S cm{sup -1} a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N{sub 2}(C-B) and is 1600 {+-} 200 K for the bubble mode and 1900 {+-} 200 K for the liquid mode. The rotational temperature of OH(A-X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), {nu} = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 10{sup 21} m{sup -3}. In the bubble mode electron densities are significantly smaller: (3-4) x 10{sup 20} m{sup -3}. These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

  1. Optical emission spectroscopy diagnostics of an atmospheric pressure direct current microplasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Sismanoglu, B.N., E-mail: bogos@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Amorim, J., E-mail: jayr.amorim@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Souza-Correa, J.A., E-mail: jorge.correa@bioetanol.org.b [Centro de Ciencia e Tecnologia do Bioetanol - CTBE, Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil); Oliveira, C., E-mail: carlosf@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil); Gomes, M.P., E-mail: gomesmp@ita.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica, Comando-Geral de Tecnologia Aeroespacial, Pca Marechal Eduardo Gomes 50, 12 228-900, Sao Jose dos Campos, SP (Brazil)

    2009-11-15

    This paper is about the use of optical emission spectroscopy as a diagnostic tool to determine the gas discharge parameters of a direct current (98% Ar-2% H{sub 2}) non-thermal microplasma jet, operated at atmospheric pressure. The electrical and optical behaviors were studied to characterize this glow discharge. The microplasma jet was investigated in the normal and abnormal glow regimes, for current ranging from 10 to 130 mA, at approx 220 V of applied voltage for copper cathode. OH (A {sup 2}SIGMA{sup +}, nu = 0 -> X {sup 2}PI, nu' = 0) rotational bands at 306.357 nm and also the 603.213 nm Ar I line, which is sensitive to van der Waals broadening, were used to determine the gas temperature, which ranges from 550 to 800 K. The electron number densities, ranging from 6.0 x 10{sup 14} to 1.4 x 10{sup 15} cm{sup -3}, were determined through a careful analysis of the main broadening mechanisms of the H{sub beta} line. From both 603.213 nm and 565.070 nm Ar I line broadenings, it was possible to obtain simultaneously electron number density and temperature (approx 8000 K). Excitation temperatures were also measured from two methods: from two Cu I lines and from Boltzmann-plot of 4p-4s and 5p-4s Ar I transitions. By employing H{sub alpha} line, the hydrogen atoms' H temperature was estimated (approx 18,000 K) and found to be surprisingly hotter than the excitation temperature.

  2. Copper Determination in Gunshot Residue by Cyclic Voltammetric and Inductive Coupled Plasma-Optical Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Mohd Hashim Nurul’Afiqah Hashimah

    2016-01-01

    Full Text Available Analysis of gunshot residue (GSR is a crucial evidences for a forensic analyst in the fastest way. GSR analysis insists a suitable method provides a relatively simple, rapid and precise information on the spot at the crime scene. Therefore, the analysis of Cu(II in GSR using cyclic voltammetry (CV on screen printed carbon electrode (SPCE is a better choice compared to previous alternative methods such as Inductive Coupled Plasma-Optical Emission Spectroscopy (ICP-OES those required a long time for analysis. SPCE is specially designed to handle with microvolumes of sample such as GSR sample. It gives advantages for identification of copper in GSR on-site preliminary test to prevent the sample loss on the process to be analyzed in the laboratory. SPCE was swabbed directly on the shooter’s arm immediately after firing and acetate buffer was dropped on SPCE before CV analysis. For ICP-OES analysis, cotton that had been soaked in 0.5 M nitric acid was swabbed on the shooter’s arm immediately after firing and kept in a tightly closed sampling tube. Gold coated SPCE that had been through nanoparticles modification exhibits excellent performance on voltammograms. The calibration was linear from 1 to 50 ppm of copper, the limit of detection for copper was 0.3 ppm and a relative standard deviation was 6.1 %. The method was successfully applied to the determination of copper in GSR. The Cu determination on SPCE was compared and validated by ICP-OES method with 94 % accuracy.

  3. Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

    International Nuclear Information System (INIS)

    Using proton magnetic resonance spectroscopy (1H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm3 (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01±0.247; controls, 1.526±0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285±0.228; controls 1.702±0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793±0.186; controls, 0.946±0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947±0.096; controls, 1.06±0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

  4. Characterization of a direct dc-excited discharge in water by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 μS cm-1 a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N2(C-B) and is 1600 ± 200 K for the bubble mode and 1900 ± 200 K for the liquid mode. The rotational temperature of OH(A-X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), ν = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 1021 m-3. In the bubble mode electron densities are significantly smaller: (3-4) x 1020 m-3. These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

  5. Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Naomi [Yamaguchi Univ., Ube (Japan). School of Medicine

    1998-04-01

    Using proton magnetic resonance spectroscopy ({sup 1}H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm{sup 3} (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01{+-}0.247; controls, 1.526{+-}0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285{+-}0.228; controls 1.702{+-}0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793{+-}0.186; controls, 0.946{+-}0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947{+-}0.096; controls, 1.06{+-}0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

  6. Physiologically gated micro-beam radiation therapy using electronically controlled field emission x-ray source array

    Science.gov (United States)

    Chtcheprov, Pavel; Hadsell, Michael; Burk, Laurel; Ger, Rachel; Zhang, Lei; Yuan, Hong; Lee, Yueh Z.; Chang, Sha; Lu, Jianping; Zhou, Otto

    2013-03-01

    Micro-beam radiation therapy (MRT) uses parallel planes of high dose narrow (10-100 um in width) radiation beams separated by a fraction of a millimeter to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000Gy of entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during the treatment can result in significant movement of micro beam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), and thus can reduce the effectiveness of the MRT. Recently we have developed the first bench-top image guided MRT system for small animal treatment using a high powered carbon nanotube (CNT) x-ray source array. The CNT field emission x-ray source can be electronically synchronized to an external triggering signal to enable physiologically gated firing of x-ray radiation to minimize motion blurring. Here we report the results of phantom study of respiratory gated MRT. A simulation of mouse breathing was performed using a servo motor. Preliminary results show that without gating the micro beam full width at tenth maximum (FWTM) can increase by 70% and PVDR can decrease up to 50%. But with proper gating, both the beam width and PVDR changes can be negligible. Future experiments will involve irradiation of mouse models and comparing histology stains between the controls and the gated irradiation.

  7. Molecular beam epitaxy growth of Si/SiGe bound-to-continuum quantum cascade structures for THz emission

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, M. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden)], E-mail: Ming.Zhao@imec.be; Karim, A.; Hansson, G.V. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Ni, W.-X. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); National Nano Device Laboratories, Hsinchu 30078, Taiwan, ROC (China); Townsend, P.; Lynch, S.A.; Paul, D.J. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE (United Kingdom)

    2008-11-03

    A Si/SiGe bound-to-continuum quantum cascade design for THz emission was grown using solid-source molecular beam epitaxy on Si{sub 0.8}Ge{sub 0.2} virtual substrates. The growth parameters were carefully studied and several samples with different boron doping concentrations were grown at optimized conditions. Extensive material characterizations revealed a high crystalline quality of the grown structures with an excellent growth control. Layer undulations resulting from a nonuniform strain field, introduced by high doping concentration, were observed. The device characterizations suggested that a modification on the design was needed in order to enhance the THz emission.

  8. Stimulated emission from a CdTe/HgCdTe separate confinement heterostructure grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Mahavadi, K.K.; Bleuse, J.; Sivananthan, S.; Faurie, J.P. (Microphysics Laboratory, Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60680 (USA))

    1990-05-21

    We present the results of low-temperature photoluminescence and stimulated emission experiments performed on a CdTe/Hg{sub 0.45}Cd{sub 0.55}Te/Hg{sub 0.67}Cd{sub 0.33}Te multiquantum well separate confinement heterostructure grown by molecular beam epitaxy. The photoluminescence results suggest that because of the growth conditions, there is a strong interdiffusion in the multiquantum well region. Pulsed stimulated emission was observed from this structure up to 77 K.

  9. Beam-line systems for pump-probe photoelectron spectroscopy using SR and laser

    CERN Document Server

    Kamada, M; Takahashi, K; Doi, Y I; Fukui, K; Kinoshita, T; Haruyama, Y; Asaka, S; Fujii, Y; Itoh, M

    2001-01-01

    Combined systems for photoelectron spectroscopy using synchrotron radiation (SR) and laser have been constructed at BL5A and BL6A2 in the UVSOR facility, Okazaki. The systems consist of photoelectron spectrometers with high performance, mode-locked lasers, and timing electronic circuits. The laser pulses with repetition frequency of 90 MHz are synchronized with the SR pulses. An upgrade project to install a micro-ESCA at BL6A2, which is now in progress, is also reported.

  10. Observation of conformers with laser electronic spectroscopy in supersonic molecular beams

    Science.gov (United States)

    Philis, John G.; Kosmidis, Constantine E.; Tsekeris, Pericles

    1998-07-01

    We discuss the ability and effectiveness of electronic spectroscopy to reveal rotational isomerism by presenting some examples of the S1 implied by S0 electronic spectra of non-rigid molecules. One or two photon electronic spectra have multiple features when the molecule has more than one conformational preference. Torsional bands showing up in the spectrum complicate the assignment of conformers. Hole burning experiments give definite conclusions on the existence of rotational isomerism and an example from the literature is given.

  11. Avalanche dynamics of structural phase transitions in shape memory alloys by acoustic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Benno

    2009-09-24

    In this work the avalanche dynamics of five shape memory samples has been analyzed by acoustic emission spectroscopy. The acoustic emission spectroscopy is particularly suitable for this analysis as it couples with high sensitivity to small structural changes caused by nucleation processes, interface movements, or variant rearrangements [91]. Owing to its high time resolution it provides a statistical approach to describe the jerky and intermittent character of the avalanche dynamics [20]. Rate-dependent cooling and heating runs have been conducted in order to study time-dependent aspects of the transition dynamics of the single crystals Ni{sub 63}Al{sub 37}, Au{sub 50.5}Cd{sub 49.5}, and Fe{sub 68.8}Pd{sup single}{sub 31.2}, and the polycrystalline sample Fe{sub 68.8}Pd{sup poly}{sub 31.2}. Moreover, a ferromagnetic Ni{sub 52}Mn{sub 23}Ga{sub 25} single crystal has been studied by temperature cycles under an applied magnetic field and additionally by magnetic-field cycles at a constant temperature in the martensitic phase. All samples analyzed in this work show power law behavior in the acoustic emission features amplitude, energy, and duration, which indicates scale-free behavior. The access to these power law spectra allows an investigation of energy barriers separating the metastable states, which give rise to avalanche transition dynamics. By performing rate-dependent experiments the importance of thermal fluctuations and the impact of martensite respectively twin stabilization processes have been examined. In the case of the Ni{sub 52}Mn{sub 23}Ga{sub 25} sample, the magnetic-field-induced variant rearrangement at slow field cycles leads to stronger signals than the rearrangement at quick cycles. This behavior can be explained by twin stabilization processes, which are accompanied by a reduction of the twin boundary mobility. For Ni{sub 63}Al{sub 37}, the combination of relevant thermal fluctuations, different involved time scales, and a high degree of

  12. Avalanche dynamics of structural phase transitions in shape memory alloys by acoustic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Benno

    2009-09-24

    In this work the avalanche dynamics of five shape memory samples has been analyzed by acoustic emission spectroscopy. The acoustic emission spectroscopy is particularly suitable for this analysis as it couples with high sensitivity to small structural changes caused by nucleation processes, interface movements, or variant rearrangements [91]. Owing to its high time resolution it provides a statistical approach to describe the jerky and intermittent character of the avalanche dynamics [20]. Rate-dependent cooling and heating runs have been conducted in order to study time-dependent aspects of the transition dynamics of the single crystals Ni{sub 63}Al{sub 37}, Au{sub 50.5}Cd{sub 49.5}, and Fe{sub 68.8}Pd{sup single}{sub 31.2}, and the polycrystalline sample Fe{sub 68.8}Pd{sup poly}{sub 31.2}. Moreover, a ferromagnetic Ni{sub 52}Mn{sub 23}Ga{sub 25} single crystal has been studied by temperature cycles under an applied magnetic field and additionally by magnetic-field cycles at a constant temperature in the martensitic phase. All samples analyzed in this work show power law behavior in the acoustic emission features amplitude, energy, and duration, which indicates scale-free behavior. The access to these power law spectra allows an investigation of energy barriers separating the metastable states, which give rise to avalanche transition dynamics. By performing rate-dependent experiments the importance of thermal fluctuations and the impact of martensite respectively twin stabilization processes have been examined. In the case of the Ni{sub 52}Mn{sub 23}Ga{sub 25} sample, the magnetic-field-induced variant rearrangement at slow field cycles leads to stronger signals than the rearrangement at quick cycles. This behavior can be explained by twin stabilization processes, which are accompanied by a reduction of the twin boundary mobility. For Ni{sub 63}Al{sub 37}, the combination of relevant thermal fluctuations, different involved time scales, and a high degree of

  13. Avalanche dynamics of structural phase transitions in shape memory alloys by acoustic emission spectroscopy

    International Nuclear Information System (INIS)

    In this work the avalanche dynamics of five shape memory samples has been analyzed by acoustic emission spectroscopy. The acoustic emission spectroscopy is particularly suitable for this analysis as it couples with high sensitivity to small structural changes caused by nucleation processes, interface movements, or variant rearrangements [91]. Owing to its high time resolution it provides a statistical approach to describe the jerky and intermittent character of the avalanche dynamics [20]. Rate-dependent cooling and heating runs have been conducted in order to study time-dependent aspects of the transition dynamics of the single crystals Ni63Al37, Au50.5Cd49.5, and Fe68.8Pdsingle31.2, and the polycrystalline sample Fe68.8Pdpoly31.2. Moreover, a ferromagnetic Ni52Mn23Ga25 single crystal has been studied by temperature cycles under an applied magnetic field and additionally by magnetic-field cycles at a constant temperature in the martensitic phase. All samples analyzed in this work show power law behavior in the acoustic emission features amplitude, energy, and duration, which indicates scale-free behavior. The access to these power law spectra allows an investigation of energy barriers separating the metastable states, which give rise to avalanche transition dynamics. By performing rate-dependent experiments the importance of thermal fluctuations and the impact of martensite respectively twin stabilization processes have been examined. In the case of the Ni52Mn23Ga25 sample, the magnetic-field-induced variant rearrangement at slow field cycles leads to stronger signals than the rearrangement at quick cycles. This behavior can be explained by twin stabilization processes, which are accompanied by a reduction of the twin boundary mobility. For Ni63Al37, the combination of relevant thermal fluctuations, different involved time scales, and a high degree of intrinsic disorder leads to a lower acoustic activity and weaker signals under decreasing cooling rates. In the

  14. γ-spectroscopy and radioactive beams: search for highly deformed exotic nuclei

    International Nuclear Information System (INIS)

    This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A ∼ 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr76 radioactive beam (T1/2 = 14.8 h). γ-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first γ transition was observed in the very exotic odd-odd Pm130 nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)

  15. Features of Electronic Emission from Surface of Dielectric Thin-film Materials with Ion-beam Etching

    Directory of Open Access Journals (Sweden)

    A. Kurochka

    2014-07-01

    Full Text Available This work presents a series of experimental studies aimed at validating the main theoretical aspects of the ion-electron emission in conditions of ion-beam etching and lookup the possibility of practical realization of the method of operative control processes ion-beam etching different dielectric thin film materials of electronic technics. In the real article the estimation of influence of the pointed superficial potential is conducted in dielectric tape on the integral signal of secondary electrons at an ionic etch. The electric field strength in dielectric film under the influence of the induced potential creates prerequisites for the emergence of "Malterovskay" emission, defined by properties actually dielectric and properties of the substrate.

  16. Proton induced γ-ray emission yields for external beam analysis of F and Na in aerosol samples

    International Nuclear Information System (INIS)

    Proton induced γ-ray emission (PIGE) is commonly used as a complementary technique of proton induced X-ray emission (PIXE) for the analysis of light elements in aerosol samples. In order to get the best operating conditions of PIGE for F and Na determination in aerosol samples relative to thin reference standards in an external beam setup, the γ-ray yields of the reaction 19F (p, p' γ) 19F (Eγ=110 keV and 197 keV) and 23Na (p, p' γ) 23Na (Eγ=440 keV) were measured for incident protons in the energy range of 1.8-2.9 MeV at the external beam facility of the 1.7 MV tandem accelerator in Beijing Normal University. (authors)

  17. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Digby Macdonald; Brian Marx; Balaji Soundararajan; Morgan Smith

    2005-07-28

    The different tasks that have been carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA), which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals, and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples in order to exactly predict the corrosion mechanisms; (7) Wavelet analysis of EC noise data from steel samples undergoing corrosion in an environment similar to that of the high level waste storage containers, to extract data pertaining to general, pitting and stress corrosion processes, from the overall data. The work has yielded a number of important findings, including an unequivocal demonstration of the role of chloride ion in passivity breakdown on nickel in terms of cation vacancy generation within the passive film, the first detection and characterization of individual micro fracture

  18. Size dependent bandgap of molecular beam epitaxy grown InN quantum dots measured by scanning tunneling spectroscopy

    International Nuclear Information System (INIS)

    InN quantum dots (QDs) were grown on Si (111) by epitaxial Stranski-Krastanow growth mode using plasma-assisted molecular beam epitaxy. Single-crystalline wurtzite structure of InN QDs was verified by the x-ray diffraction and transmission electron microscopy. Scanning tunneling microscopy has been used to probe the structural aspects of QDs. A surface bandgap of InN QDs was estimated from scanning tunneling spectroscopy (STS) I-V curves and found that it is strongly dependent on the size of QDs. The observed size-dependent STS bandgap energy shifts with diameter and height were theoretical explained based on an effective mass approximation with finite-depth square-well potential model.

  19. In situ photoelectron spectroscopy study of TiCxNy films synthesized through reactive ion beam mixing

    International Nuclear Information System (INIS)

    Oxygen-free TiCxNy films have been prepared using the reactive ion beam mixing technique. A 400 A thick film of Ti was deposited on a float glass substrate and then coated with a 80 A Carbon layer. These bilayer structures were irradiated by 4 keV nitrogen ions for different nitrogen doses. In situ core level x-ray photoelectron spectroscopy (XPS) measurements were carried out to characterize these films. XPS results revealed that after nitrogen ion bombardment a sufficient amount of nitrogen was introduced in the Ti/C bilayer. On the basis of the binding energy parameters of the Ti 2p, N 1s and C 1s core levels and their shifts from the elemental position, the formation of compound TiCxNy near the surface is confirmed. The XPS result of formation of TiCxNy is supported by x-ray diffraction measurements

  20. Analysis of the fine structure of Sn$^{11+...14+}$ ions by optical spectroscopy in an electron beam ion trap

    CERN Document Server

    Windberger, A; Borschevsky, A; Ryabtsev, A; Dobrodey, S; Bekker, H; Eliav, E; Kaldor, U; Ubachs, W; Hoekstra, R; López-Urrutia, J R Crespo; Versolato, O O

    2016-01-01

    We experimentally re-evaluate the fine structure of Sn$^{11+...14+}$ ions. These ions are essential in bright extreme-ultraviolet (EUV) plasma-light sources for next-generation nanolithography, but their complex electronic structure is an open challenge for both theory and experiment. We combine optical spectroscopy of magnetic dipole $M1$ transitions, in a wavelength range covering 260\\,nm to 780\\,nm, with charge-state selective ionization in an electron beam ion trap. Our measurements confirm the predictive power of \\emph{ab initio} calculations based on Fock space coupled cluster theory. We validate our line identification using semi-empirical Cowan calculations with adjustable wavefunction parameters. Available Ritz combinations further strengthen our analysis. Comparison with previous work suggests that line identifications in the EUV need to be revisited.

  1. Measurement of free radical kinetics in pulsed plasmas by UV and VUV absorption spectroscopy and by modulated beam mass spectrometry

    International Nuclear Information System (INIS)

    This paper reviews recent progress in the development of time-resolved diagnostics to probe high-density pulsed plasma sources. We focus on time-resolved measurements of radicals' densities in the afterglow of pulsed discharges to provide useful information on production and loss mechanisms of free radicals. We show that broad-band absorption spectroscopy in the ultraviolet and vacuum ultraviolet spectral domain and threshold ionization modulated beam mass spectrometry are powerful techniques for the determination of the time variation of the radicals' densities in pulsed plasmas. The combination of these complementary techniques allows detection of most of the reactive species present in industrial etching plasmas, giving insights into the physico-chemistry reactions involving these species. As an example, we discuss briefly the radicals' kinetics in the afterglow of a SiCl4/Cl2/Ar discharge. (paper)

  2. Inhibition of type III radio emissions due to the interaction between two electron beams: Observations and simulations

    OpenAIRE

    Briand, C; Henri, P.; Hoang, S

    2014-01-01

    We report the peculiar interaction of two type III bursts observed in the solar wind. As electronbeams propagating on the same magnetic field lines cross, a spectacular depletion of the type III radioemission is observed. We combine observations from the WAVES experiment on board the STEREO missiontogether with kinetic plasma simulations to study the extinction of type III radio emission resulting fromthe interaction between two electron beams. The remote observations enable to follow the ele...

  3. Measurement of (n,xn) reaction cross-sections using prompt γ spectroscopy at neutron beams with high instantaneous flux

    International Nuclear Information System (INIS)

    The work presented in this thesis is situated in the context of the GEDEON program of neutron cross-section measurements. This program is motivated by the perspectives recently opened by projects of nuclear waste treatment and energy production. There is an obvious lack of experimental data on (n,xn) reactions in the databases, especially in the case of very radioactive isotopes. An important technique to measure cross-sections of these reactions is the prompt γ-ray spectroscopy at white pulsed neutron beams with very high instantaneous flux. In this work, inelastic scattering and (n,xn) reactions cross-section measurements were performed on a lead sample from threshold to 20 MeV by prompt γ-ray spectroscopy at the white neutron beam generated by GELINA facility in Geel, Belgium. Digital methods were developed to treat HPGe CLOVER detector signals and separate γ-rays induced by the fastest neutrons from those belonging to the flash. Partial cross-sections for the production of several transitions in natural lead were measured and analyzed using theoretical calculations in order to separate the contributions of different reactions leading to the same residual isotope. Total cross-sections of the reactions in question were estimated. The results were compared to the TALYSS code theoretical calculations, as well as to other experimental results. This experiment has served to validate the method and it opens the way to measure (n,xn) reactions cross-sections with high instantaneous neutron flux on actinides, particularly the U233(n,2n) reaction which is important for the thorium cycle. (author)

  4. Emission Line Astronomy - Coronagraphic Tunable Narrow Band Imaging and Integral Field Spectroscopy. Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to continue our program of emission line astronomy featuring three areas of emphasis: 1) The distribution and nature of high redshift emission line...

  5. Laser Induced Emission Spectroscopy of Cold and Isolated Neutral PAHs and PANH: Implications for the red rectangle emission

    Science.gov (United States)

    Bejaoui, Salma; Salama, Farid; Sciamma O'Brien, Ella

    2016-06-01

    Blue luminescence (BL) in the emission spectra of the red rectangle centered on the bright star HD44179 is recently reported by Vijh et al [1]. This results is consistent with the broad band polarization measurements obtained in 1980 by Schmidt et al. Both experimental and theoretical studies support that BL emission could be attributed the luminescence of Polycyclic Aromatic Hydrocarbon (PAH) excited with ultraviolet light from the center of the star [4 and reference therein]. The abundance on N to C in the interstellar medium suggest also that nitrogen substituted PAH (PANH) are likely abundant in the interstellar medium [3]. They exhibit similar features as PAHs and could contribute to the unidentified spectral bands. Comparing the BL to laboratory spectra obtained on similar environment is crucial for the identification of interstellar molecules. We present in this works the absorption and the laser induced emission spectra of several isolated and cold PAHs and PANHs. Laser induced emission was performed first to PAHs and PANHs isolated in Argon matrix at 10 K. Then, measurements are performed with the supersonic jet technique of the COSmIC laboratory facility at NASA Ames. We focus, here, on the emission spectra (fluorescence and (or) phosphorescence) of these molecules and we discuss their contributions to the blue luminescence emission in the Red Rectangle nebula.[1] Vijh,U.P., Witt. A.N. & Gordon,K.D, APJ, 606, L69 (2004)[2] Schmidt, G. D., Cohen, M. & Margon, B., ApJ, 239L.133S (1980)[3] Spitzer, L., Physical Processes in the Interstellar Medium (New York Wiley-Interscience) (1978)[4] Salama, F., Galazutdinov, G. A., Kre lowski, J., Allamandola, L. J., & Musaev, F. A. ApJ, 526,(1999)

  6. Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 2: Wind propagation and emission rates

    OpenAIRE

    Krueger, A.; Stremme, W.; Harig, R.; Grutter, M.

    2013-01-01

    A technique for measuring two-dimensional (2-D) plumes of volcanic gases with thermal emission spectroscopy was described in Part 1 by Stremme et al. (2012a). In that paper the instrumental aspects as well as retrieval strategies for obtaining the slant column images of SO2 and SiF4, as well as animations of particular events observed at the Popocatépetl volcano, were presented. This work focuses on the procedures for determining the propagation speed of the gases and...

  7. Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 2: Wind propagation and emission fluxes

    OpenAIRE

    Harig, R.; Grutter, M.; Stremme, W.; Krueger, A.

    2012-01-01

    The technique for measuring two-dimensional (2-D) plumes of volcanic gases with thermal emission spectroscopy was described in Part 1 by Stremme et al. (2012). In that paper the instrumental aspects as well as retrieval strategies for obtaining the slant column images of SO2 and SiF4, as well as animations of particular events observed at the Popocatépetl volcano, were presented. This work focuses on the procedures for determining the propagation speed of the gases and estimating an emis...

  8. An atomic hydrogen beam to test ASACUSA’s apparatus for antihydrogen spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diermaier, M., E-mail: martin.diermaier@oeaw.ac.at; Caradonna, P.; Kolbinger, B. [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics (Austria); Malbrunot, C. [CERN (Switzerland); Massiczek, O.; Sauerzopf, C.; Simon, M. C.; Wolf, M.; Zmeskal, J.; Widmann, E. [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics (Austria)

    2015-08-15

    The ASACUSA collaboration aims to measure the ground state hyperfine splitting (GS-HFS) of antihydrogen, the antimatter counterpart to atomic hydrogen. Comparisons of the corresponding transitions in those two systems will provide sensitive tests of the CPT symmetry, the combination of the three discrete symmetries charge conjugation, parity, and time reversal. For offline tests of the GS-HFS spectroscopy apparatus we constructed a source of cold polarised atomic hydrogen. In these proceedings we report the successful observation of the hyperfine structure transitions of atomic hydrogen with our apparatus in the earth’s magnetic field.

  9. Internal-state thermometry by depletion spectroscopy in a cold guided beam of formaldehyde

    CERN Document Server

    Motsch, M; Van Buuren, L D; Zeppenfeld, M; Pinkse, P W H; Rempe, G

    2007-01-01

    We present measurements of the internal state distribution of electrostatically guided formaldehyde. Upon excitation with continuous tunable ultraviolet laser light the molecules dissociate, leading to a decrease in the molecular flux. The population of individual guided states is measured by addressing transitions originating from them. The measured populations of selected states show good agreement with theoretical calculations for different temperatures of the molecule source. The purity of the guided beam as deduced from the entropy of the guided sample using a source temperature of 150K corresponds to that of a thermal ensemble with a temperature of about 30 K.

  10. Automatic laser beam alignment using blob detection for an environment monitoring spectroscopy

    Science.gov (United States)

    Khidir, Jarjees; Chen, Youhua; Anderson, Gary

    2013-05-01

    This paper describes a fully automated system to align an infra-red laser beam with a small retro-reflector over a wide range of distances. The component development and test were especially used for an open-path spectrometer gas detection system. Using blob detection under OpenCV library, an automatic alignment algorithm was designed to achieve fast and accurate target detection in a complex background environment. Test results are presented to show that the proposed algorithm has been successfully applied to various target distances and environment conditions.

  11. FEASIBILITY STUDY TO DEMONSTRATE APPLICABILITY OF TUNABLE INFRARED LASER EMISSION SPECTROSCOPY TECHNOLOGY TO MEASURE AIR POLLUTION

    Science.gov (United States)

    This project involves the real-time measurement of air quality using open-path IR spectroscopy. A prototype open-path tunable laser absorption spectroscopy instrument was designed, built, and successfully operated for several hundred hours between October and December 2000. The...

  12. Particle effects on the emissivity and temperature of optically thick, mixed media retrieved by mid-IR emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rego-Barcena, S.; Thomson, M.J. [University of Toronto, Toronto, ON (Canada)

    2008-05-15

    Passive diagnostics offer new ways of obtaining real-time data for the control and modeling of industrial furnaces. It has been proposed elsewhere that from the intensity profile between 3.8 and 4.7 {mu} m one may derive the temperature of a gas-particle medium and the particle emissivity ({epsilon}{sub p}) at 3.95 {mu} m. This technique applies to large columns of combustion products with enough CO{sub 2}. The temperature is retrieved by finding the best fit between Planck's function and the intensity profile between 4.56 and 4.7 {mu} m, which is that of a blackbody due to CO{sub 2} saturation. Here we consider the effect of particles on the intensity profile and, therefore, on the retrieved temperature and particle emissivity. We derive an analytic approximation of the effective emissivity for an optically thick gas-particle mixture that includes emission and absorption due to particles and gases, along with isotropic particle scattering. The derivation follows the method of embedded invariance and has been used already for particle-only clouds. It yields a spectral solution that is applicable in other infrared regions where gas and particle optical thicknesses are large. A key parameter {chi} is the ratio of the gas absorption coefficient to the particle extinction coefficient. For {chi}=1 and {epsilon}{sub p} = 0.5, particle effects decrease the gas band profile by 5% from that of a blackbody. For {chi} {lt}1 and {epsilon}{sub p} {lt} 0.5, particle effects on the calculated temperature and particle emissivity are noticeable and particle effects should be considered. If chi is known, an iterative procedure may be used to calculate temperature and particle emissivity. We illustrate this procedure with data from a coal-fired boiler. Accounting for particle effects, temperatures were 4% higher (at about 1500 K) and particle emissivities 28% lower (for {epsilon}{sub p} within 0.3-05) than without considering these effects.

  13. Spectroscopy of high lying resonances in 9Be produced with radioactive 8Li beams

    International Nuclear Information System (INIS)

    We present the results of the 8Li(p,α)5He and 8Li(p,p)8Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil) system. The experiment was realized in inverse kinematics using a thick [CH2]n polyethylene target and an incident 8Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between Ecm = 0.2 - 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the 8Li(p,α)5He reaction, populating resonances between 16.888 and 19.0 MeV in 9Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in 9Be. The measurement of the resonant elastic scattering 8Li(p,p)8Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented. (author)

  14. Spectroscopy of high lying resonances in 9Be produced with radioactive 8Li beams

    Directory of Open Access Journals (Sweden)

    Lépine-Szily A.

    2014-04-01

    Full Text Available We present the results of the 8Li(p,α5He and 8Li(p,p8Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil system. The experiment was realized in inverse kinematics using a thick [CH2]n polyethylene target and an incident 8Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between Ecm = 0.2 − 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the 8Li(p,α5He reaction, populating resonances between 16.888 and 19.0 MeV in 9Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in 9Be. The measurement of the resonant elastic scattering 8Li(p,p8Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented.

  15. Extreme ultraviolet beam-foil spectroscopy of highly ionized neon and argon

    International Nuclear Information System (INIS)

    A study of the euv radiation emitted by ion beams of highly ionized Ne and Ar after passage through thin foils was conducted at the variable energy cyclotron at Texas A and M University. A grazing incidence spectrometer was equipped with a position sensitive microchannel plate (MCP) detector, which improved the detection efficiency by two orders of magnitude. The position information of the MCP was determined to be linear over 90% of the 50 mm wide detector. Spectra spanning regions of over 100 A were accumulated at a resolution of less than 1 A. A wavelength calibration based on a second order equation of spectrometer position was found to result in an accuracy of +/-0.1 A. Over 40 transitions of Ne VIII, Ne IX, and Ne X were observed in the wavelength region from 350 to 30 A from n = 2-3, 4, 5; n = 3-4, 5, 6, 7, 8; n = 4-6, 7; and n = 5-9. An intensity calibration of the detection system allowed the determination of the relative populations of n = 3 states of Ne VIII and Ne IX. The argon beam-foil data confirmed the wavelength predictions of 30 previously unobserved transitions in the wavelength region from 355 to 25 A from n = 2-2; n = 3-4; n = 4-5, 6, 7; n = 5-6, 7; and n = 6-8

  16. Investigation of reactions relevant for the γ process using in-beam γ-ray spectroscopy

    Science.gov (United States)

    Netterdon, L.; Endres, J.; Mayer, J.; Sauerwein, A.; Scholz, P.; Zilges, A.

    2016-01-01

    The reaction 89Y(p, γ)90Zr was studied at five proton energies close to the Gamow window. This reaction is of astrophysical importance, since it is located in a mass region, where the p-nuclei abundances are not well reproduced by network calculations. For this purpose, the in-beam technique utilizing the high-efficiency high-purity germanium (HPGe) detector array HORUS at the Tandem ion accelerator at the University of Cologne was used. The excellent agreement of the measured total cross sections with previous data shows, that the setup in Cologne is well suited for such measurements. An additional interesting outcome of this measurement are partial cross sections of the de-excitation of the 90 Zr compund nucleus up to the 15th excited state, an observable only accessible in this kind of high-resolution inbeam experiments. The experimental setup and preliminary results of the total and partial cross sections obtained for the 89Y(p, γ) reaction are presented. Additionally, we show results of a first test measurement of the a-capture reaction on the p-nucleus 92Mo using the in-beam technique with HPGe detectors.

  17. Development of gas cluster ion beam surface treatments for reducing field emission and breakdown in RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, D R; Degenkolb, E; Wu, A T; Insepov, Z

    2006-11-01

    Sub-micron-scale surface roughness and contamination cause field emission that can lead to high voltage breakdown of electrodes, and these are limiting factors in the development of high gradient RF technology. We are studying various Gas Cluster Ion Beam (GCIB) treatments to smooth, clean, etch and/or chemically alter electrode surfaces to allow higher fields and accelerating gradients, and to reduce the time and cost of conditioning high voltage electrodes. For this paper, we have processed Nb, Stainless Steel, and Ti electrode materials using beams of Ar, O2, or NF3 +O2 clusters with accelerating potentials up to 35 kV. Using a Scanning Field Emission Microscope (SFEM), we have repeatedly seen a dramatic reduction in the number of field emission sites on Nb coupons treated with GCIB. Smoothing effects on Stainless steel and Ti substrates have been evaluated using AFM imaging and show that 200-nm wide polishing scratch marks are greatly attenuated. A 150-mm diameter GCIB treated stainless steel electrode has now shown virtually no DC field emission current at gradients over 20 MV/m.

  18. Inductively coupled plasma-atomic emission spectroscopy glovebox assembly system at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    The inductively coupled plasma/atomic emission spectroscopy [ICP/AES (ICP)] system for elemental analyses in support of vitrification processing was first installed in 1986. The initial instrument was a Jobin Yvon (JY) Model JY-70 ICP that consisted of sequential and simultaneous spectrometers for analysis of nonradioactive samples as radioactive surrogates. The JY-70 ICP continued supporting nonradioactive testing during the Functional and Checkout Testing of Systems (FACTS) using the full-scale melter with ''cold'' (nonradioactive) testing campaigns. As a result, the need for another system was identified to allow for the analysis of radioactive samples. The Mass Spec (Spectrometry) Lab was established for the installation of the modified ICP system for handling radioactive samples. The conceptual setup of another ICP was predicated on the use of a hood to allow ease of accessibility of the torch, nebulizer, and spray chamber, and the minimization of air flow paths. However, reconsideration of the radioactive sample dose rate and contamination levels led to the configuration of the glovebox system with a common transfer interface box for the ICP and the inductively coupled plasma-mass spectrometer (ICP-MS) glovebox assemblies. As a result, a simultaneous Model JY-50P ICP with glovebox was installed in 1990 as a first generation ICP glovebox system. This was one of the first ICP glovebox assemblies connected with an ICP-MS glovebox system. Since the economics of processing high-level radioactive waste (HLW) required the availability of an instrument to operate 24 hours a day throughout the year without any downtime, a second generation ICP glovebox assembly was designed, manufactured, and installed in 1995 using a Model JY-46P ICP. These two ICP glovebox systems continue to support vitrification of the HLW into canisters for storage. The ICP systems have been instrumental in monitoring vitrification batch processing. To date, remote sample preparation and

  19. The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge

    CERN Document Server

    Cortázar, O D; Tarvainen, O; Kalvas, T; Koivisto, H

    2015-01-01

    The relationship between Balmer-α and Fulcher-band emissions with extracted H +, H+2 , and H+3 ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical view-port on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed.

  20. Study of emission episodes of urban aerosol by ion beam analytical techniques

    International Nuclear Information System (INIS)

    atmospheric aerosol in Debrecen were biomass burning (S-K-rich particles), which in our case is domestic heating in winter and field burning in summer. Furthermore trace metals originated from traffic or industrial emission. Zn compounds could be abrasion products of brake and tire wear of cars. Ni and V originated from oil combustion. Pb was products of winter tyre abrasion, industrial emission or waste burning. Origin of salts was sea-salt, fertilizer or construction. Single particle analysis in the combination of ion beam analytical methods and electron microscopy proved to be a powerful tool in the characterization of atmospheric aerosol particles in the micrometer size range. Acknowledgement. This work was supported by the Hungarian Research Fund OTKA and the EGT Norwegian Financial Mechanism Programme (contract no. NNF78829) and the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences.

  1. Optical emission spectroscopy characterizations of micro-air plasma used for simulation of cell membrane poration

    Science.gov (United States)

    Zerrouki, A.; Motomura, H.; Ikeda, Y.; Jinno, M.; Yousfi, M.

    2016-07-01

    A micro-air corona discharge, which is one of the plasmas successfully used for gene transfection in terms of high transfection and cell viability rates, is characterized by optical emission spectroscopy. This non-equilibrium low temperature plasma is generated from the tip of a pulsed high voltage micro-tube (0.2 mm inner diameter and 0.7 mm for outer diameter) placed 2 mm in front of a petri dish containing deionized water and set on a grounded copper plate. The electron temperature, equal to about 6.75 eV near the electrode tip and decreased down to 3.4 eV near the plate, has been estimated, with an error bar of about 30%, from an interesting approach based on the experimental ratio of the closest nitrogen emission spectra of \\text{N}2+ (FNS) at 391.4 nm and N2(SPS) at 394.3 nm. This is based on one hand on a balance equation between creations and losses of the excited upper levels of these two UV spectra and on the other hand on the electron impact rates of the creation of these upper levels calculated from solution of the multi-term Boltzmann equation. Then using the measured Hα spectrum, electron density n e has been estimated from Stark broadening versus the inter-electrode position with an average error bar of about 50%. n e  ≈  1  ×  1015 cm‑3 is near the tip coherent with the usual magnitude of electron density in the streamer head developed near the tip of the corona discharges. Rotational temperatures, estimated from comparison of synthetic and experimental spectra of OH(A  ‑  X), \\text{N}2+ (FNS) at 391.4 nm, and N2(SPS) at 337 nm are respectively equal to 2350 K, 2000 K and 700 K in the gap space. This clearly underlines a thermal non-equilibrium of the corresponding excited species generated inside the thin streamer filaments. But, due to the high dilution of these species in the background gas, these high rotational temperatures do not affect the mean gas temperature that remains close to 300

  2. Intense ion beam generation in a diode with explosive emission cathode in self-magnetically insulated mode

    International Nuclear Information System (INIS)

    This paper presents a review of experimental studies on pulsed intense ion beam generation in self-magnetically insulated diodes with an explosive emission cathode. The experiments were carried out with the TEMP-4M ion accelerator operating in double-pulse mode: the first pulse is of negative polarity (300-500 ns, 100-150 kV), and this is followed by a second pulse of positive polarity (150 ns, 250-300 kV). The ion beam energy density is 0.5-5 J/cm2 depending on the diode geometry. We have developed a new spiral geometry of the diode. In a spiral diode it is possible to increase the efficiency from 5-9% (previously studied diodes) up to 20-25%. We conducted a study on shot-to-shot variation in the ion beam parameters. It was found that the standard deviation of the energy density does not exceed 11%, whilst the same variation for ion current density was 20-30%. Focusing properties of an ion beam have been significantly improved by using a metal shield on the grounded electrode. Use of the shield on the grounded electrode provides decrease in the beam divergence from 11 to 7.5-8 degrees. (authors)

  3. Multi-epoch Spectroscopy of Dwarf Galaxies with AGN Signatures: Identifying Sources with Persistent Broad H-alpha Emission

    CERN Document Server

    Baldassare, Vivienne F; Gallo, Elena; Greene, Jenny E; Graur, Or; Geha, Marla; Hainline, Kevin; Carroll, Christopher M; Hickox, Ryan C

    2016-01-01

    We use time-domain optical spectroscopy to distinguish between broad emission lines powered by accreting black holes (BHs) or stellar processes (i.e., supernovae) for 16 galaxies identified as AGN candidates by Reines et al. (2013). 14 of these have star-formation--dominated narrow-line emission ratios, one is a narrow-line AGN, and the last is a star-forming--AGN composite. We find that broad H$\\alpha$ emission has faded for 11/16 targets, based on spectra taken with the Magellan Echellette Spectrograph (MagE), the Dual Imaging Spectrograph, and the Ohio State Multi-Object Spectrograph with baselines ranging from 5 to 14 years. The 11 faded systems all have narrow-line ratios consistent with recent star formation, suggesting the broad emission for those targets was produced by a transient stellar process. The two objects with narrow-line AGN signatures (RGG 9 and RGG 119) have persistent broad H$\\alpha$ emission consistent with previous SDSS observations. The final three star-forming objects are classified a...

  4. Optical emission spectroscopy study in the VUV-VIS regimes of a developing low-temperature plasma in nitrogen gas

    Science.gov (United States)

    Fierro, A.; Laity, G.; Neuber, A.

    2012-12-01

    The mechanisms leading to the development of an atmospheric low temperature plasma along a surface under pulsed conditions is of current interest. In the early plasma phase, high energy photons are a contributing factor to the process of generating electron avalanches resulting in surface flashover. Since only photons in the vacuum ultraviolet (VUV) regime are energetic enough to cause step-ionization or direct ionization of atmospheric gases, an experiment has been set up to enable observations of photons with wavelengths shorter than 200 nm while still allowing observation up to 800 nm. A spectrum simulation software package has been developed to allow for temperature analysis on the developing plasma in the VUV region. Observations below 200 nm revealed a Boltzmann distributed excited state population corresponding to a temperature of 3.1 eV. Time-resolved emission spectroscopy measurements of the entire electrode region during the streamer phase of breakdown demonstrate the presence of molecular nitrogen emission lines from the second positive system. Further photomultiplier tube measurements of the spark phase showed a rapid decrease in intensity of the second positive system compared to that of a representative atomic emission line in the VUV regime. This emission dominates the ultraviolet-visible (UV-VIS) spectrum during the initial phases of breakdown with little detection of other sources of emission during this phase.

  5. Development of desolvation system for single-cell analysis using droplet injection inductively coupled plasma atomic emission spectroscopy

    International Nuclear Information System (INIS)

    With a view to enhance the sensitivity of analytical instruments used in the measurement of trace elements contained in a single cell, we have now equipped the previously reported micro-droplet injection system (M-DIS) with a desolvation system. This modified M-DIS was coupled to inductively coupled plasma atomic emission spectroscopy (ICP-AES) and evaluated for its ability to measure trace elements. A flow rate of 100 mL/min for the additional gas and a measurement point –7.5 mm above the load coil (ALC) have been determined to be the optimal parameters for recording the emission intensity of the Ca(II) spectral lines. To evaluate the influence of the desolvation system, we recorded the emission intensities of the Ca(I), Ca(II), and H-β spectral lines with and without inclusion of the desolvation system. The emission intensity of the H-β spectral line reduces and the magnitude of the Ca(II)/Ca(I) emission intensity ratio increases four-fold with inclusion of the desolvation system. Finally, the elements Ca, Mg, and Fe present in a single cell of Pseudococcomyxa simplex are simultaneously determined by coupling the M-DIS equipped with the desolvation system to ICP-AES. (author)

  6. DuMond curved crystal spectrometer for in-beam X- and gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    An in-beam curved crystal spectrometer facility has been installed at the SIN variable energy cyclotron. The radius of curvature is 3.15 m. Using the (110) planes of different bent quartz laminas, diffraction peaks down to Δθ = 5 arcsec FWHM are obtained. The energy resolution is thus ΔE ≅ 0.01 E2/n, where n is the diffraction order, ΔE being expressed in eV and E in keV. The spectrometer has been constructed to cover an angular range of ±100. Transitions in the range 17 to about 350 keV have so far been observed. Measurements have been performed in conventional line source DuMond geometry and in slit geometry. The instrument is being used for the high-resolution observation of X- and gamma-rays induced by proton, helium- and oxygen-ion bombardment. (orig.)

  7. Discovery of new magic number via in-beam γ-ray spectroscopy

    International Nuclear Information System (INIS)

    The atomic nucleus is a finite quantum system composed of protons and neutrons. In a way similar to electrons in an atom, protons and neutrons in the nucleus exhibit shell structures. In the case of stable nuclei, which exist naturally in the Universe, large energy gaps persist between shells that fill when the proton or neutron number equals 2, 8, 20, 28, 50, 82 or 126. However, far from the line of β stability, these magic numbers can change in nuclei that contain a large excess of neutrons. While some of the traditional shell closures disappear, other new ones are known to present themselves. Here, we report on a study of the exotic nucleus 54Ca using proton removal reactions from 55Sc and 56Ti projectiles at the RIKEN Radioactive Isotope Beam Factory. The results indicate a doubly magic structure for 54Ca and, accordingly, provide the first experimental evidence for a new subshell closure at neutron number 34. (author)

  8. In-beam γ-ray spectroscopy of Pt isotopes located at the proton drip line

    International Nuclear Information System (INIS)

    In-beam γ rays have been observed in the neutron-deficient isotopes 170,171,172Pt using the recoil-decay tagging technique. The yrast transition sequence proposed for 172Pt indicates that the 0+ bandhead of the deformed intruder band is situated about 900 keV above the weakly deformed ground state, i.e., its excitation energy has risen by about 300 keV compared to 174Pt. The measured energy of the 2+→0+ transition in 170Pt supports an even larger increase in the excitation energy of the intruder configuration with the departure from the middle of the 82 endash 126 major neutron shell. Furthermore, a band with transition energies almost identical to those found in 172Pt has been assigned to 171Pt and was interpreted as corresponding to a rotationally aligned i13/2 neutron orbital coupled to the core excitations. copyright 1998 The American Physical Society

  9. Supersonic molecular beam electric resonance spectroscopy and van der Waals molecules

    International Nuclear Information System (INIS)

    A supersonic molecular beam electric resonance (MBER) spectrometer was built to study the radiofrequency spectra of weakly bound gas phase van der Waals molecules. The instrument and its operating characteristics are described in detail. Sample mass spectra of Ar-ClF gas mixtures are also presented as an illustration of the synthesis of van der Waals molecules. The Stark focusing process for linear polar molecules is discussed and computer-simulated using both second order perturbation and variational methods. Experimental refocusing spectra of OCS and ClF are studied and compared with these trajectory calculations. Though quantitative fitting is poor, there are strong qualitative indicators that the central part of a supersonic beam consists of molecules with a significantly greater population in the lowest energy rotational states than generally assumed. Flop in as opposed to flop out resonance signals for OCS are also numerically predicted and observed. The theoretical properties of the MBER spectrum for linear molecules are elaborated upon with special emphasis on line shape considerations. MBER spectra of OCS and ClF under a variety of conditions are presented and discussed in context to these predictions. There is some uncertainty expressed both in our own modeling and in the manner complex MBER spectra have been analyzed in the past. Finally, an electrostatic potential model is used to quantitatively describe the class of van der Waals molecules Ar-MX, where MX is an alkali halide. Energetics and equilibrium geometries are calculated. The validity of using an electrostatic model to predict van der Waals bond properties is critically discussed

  10. Dynamics of double-pulse laser produced titanium plasma inferred from thin film morphology and optical emission spectroscopy

    International Nuclear Information System (INIS)

    In this paper, dynamics of double-pulse laser produced titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasma dynamics was monitored using optical emission spectroscopy with spatial and temporal resolutions. The influence of ablation mode (single and double) and delay time τ (delay between first and second pulses in double-pulse mode) on plasma dynamics and consequently on morphology of deposited Ti-films was studied using X-ray reflectivity and atomic force microscopy. Delay time τ was varied from 170 ns to 4 μs. The results show strong dependence of both emission signal and Ti-film properties, such as thickness, density and roughness, on τ. In addition, correlation of average density and thickness of film is observed. These results are discussed in terms of dependency of angular distribution and kinetic energy of plasma plume particles on τ. Advantages of using double-pulse laser deposition for possible application in thin film production are shown. - Highlights: • Ti-thin films produced by single and double pulse laser ablation mode. • Ablation mode and delay time influenced plasma plume and film characteristics. • Films are most compact for optimized delay time (thinnest, smoothest and most dense). • Plasma dynamics can be inferred from film characteristics

  11. Absolute and relative emission spectroscopy study of 3 cm wide planar radio frequency atmospheric pressure bio-plasma source

    Science.gov (United States)

    Deng, Xiaolong; Nikiforov, Anton Yu; Ionita, Eusebiu-Rosini; Dinescu, Gheorghe; Leys, Christophe

    2015-08-01

    The dynamics of low power atmospheric pressure radio frequency discharge generated in Ar gas in long gap of 3 cm is investigated. This plasma source is characterized and analyzed for possible large scale biomedical applications where low gas temperature and potential-less effluent are required. The discharge forms a homogenous glow-like afterglow in ambient air at input power of 30 W with low gas temperature of 330 K, which is desirable in biomedical applications. With absolute calibrated spectroscopy of the discharge, electron density of 0.4 × 1018 m-3 and electron temperature of 1.5 eV are obtained from continuum Bremsstrahlung radiation of the source. Time and spatial resolved emission spectroscopy is used to analyze discharge generation mechanism and active species formation. It is found that discharge dynamics strongly correlates with the discharge current waveform. Strong Ar(2p) excited states emission is observed nearby the electrodes surface on a distance up to 200 μm in the plasma sheath region at 10 ns after the current peak, whereas OH(A) emission is uniform along of the interelectrode gap.

  12. Charge exchange recombination spectroscopy measurements in the extreme ultraviolet region of central carbon concentrations during high power neutral beam heating in TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The carbon concentration in the central region of TFTR discharges with high power neutral beam heating has been measured by charge-extracted recombination spectroscopy (CXRS) of the C+5 n = 3--4 transition in the extreme ultraviolet region. The carbon concentrations were deduced from absolute measurements of the line brightness using a calculation of the beam attenuation and the appropriate cascade-corrected line excitation rates. As a result of the high ion temperatures in most of the discharges, the contribution of beam halo neutrals to the line brightness was significant and therefore had to be included in the modeling of the data. Carbon concentrations have been measured in discharges with Ip = 1.0-1.6 MA and beam power in the range of 2.6-30 MW, including a number of supershots. The results are in good agreement with carbon concentrations deduced from the visible bremsstrahlung Zeff and metallic impurity concentrations measured by x-ray pulse-height analysis, demonstrating the reliability of the atomic rates used in the beam attenuation and line excitation calculations. Carbon is the dominant impurity species in these discharges; the oxygen concentration measured via CXRS in a high beam power case was 0.0006 of ne, compard to 0.04 for carbon. Trends with Ip and beam power in the carbon concentration and the inferred deuteron concentration are presented. The carbon concentration is independent of Ip and decreases from 0.13 at 2.6 MW beam power to 0.04 at 30 MW, while the deuteron concentration increases from 0.25 to 0.75 over the same range of beam power. These changes are primarily the result of beam particle fueling, as the carbon density did not vary significantly with beam power. The time evolutions of the carbon and deuteron concentrations during two high power beam pulses, one which exhibited a carbon bloom and one which did not, are compared. 30 refs., 12 figs., 2 tabs

  13. An electron impact emission spectroscopy flux sensor for monitoring deposition rate at high background gas pressure with improved accuracy

    International Nuclear Information System (INIS)

    Electron impact emission spectroscopy (EIES) has been proven to be a critical tool for film composition control during codeposition processes for the fabrication of multicomponent thin film materials including the high-efficiency copper-indium-gallium-diselenide photovoltaic cells. This technique is highly specific to atomic species because the emission spectrum of each element is unique, and the typical width of atomic emission lines is very narrow. Noninterfering emission lines can generally be allocated to different atomic species. However, the electron impact emission spectra of many molecular species are often broadband in nature. When the optical emission from an EIES sensor is measured by using a wavelength selection device with a modest resolution, such as an optical filter or monochromator, the emissions from common residual gases may interfere with that from the vapor flux and cause erroneous flux measurement. The interference is most pronounced when measuring low flux density with the presence of gases such as in reactive deposition processes. This problem is solved by using a novel EIES sensor that has two electron impact excitation sources in separate compartments but with one common port for optical output. The vapor flux is allowed to pass through one compartment only. Using a tristate excitation scheme and appropriate signal processing technique, the interfering signals from residual gases can be completely eliminated from the output signal of the EIES monitor for process control. Data obtained from Cu and Ga evaporations with the presence of common residual gases such as CO2 and H2O are shown to demonstrate the improvement in sensor performance. The new EIES sensor is capable of eliminating the effect of interfering residual gases with pressure as high as in the upper 10-5 Torr range

  14. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Digby D. Macdonald; Brian M. Marx; Sejin Ahn; Julio de Ruiz; Balaji Soundararaja; Morgan Smith; and Wendy Coulson

    2008-01-15

    Various forms of general and localized corrosion represent principal threats to the integrity of DOE liquid waste storage tanks. These tanks, which are of a single wall or double wall design, depending upon their age, are fabricated from welded carbon steel and contain a complex waste-form comprised of NaOH and NaNO{sub 3}, along with trace amounts of phosphate, sulfate, carbonate, and chloride. Because waste leakage can have a profound environmental impact, considerable interest exists in predicting the accumulation of corrosion damage, so as to more effectively schedule maintenance and repair. The different tasks that are being carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA) which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples

  15. In-beam spectroscopy of very neutron deficient polonium isotopes 190,191Po

    International Nuclear Information System (INIS)

    The phenomenon of shape coexistence is experimentally well established in even-even light Pb, Hg and Pt nuclei. The light Po isotopes are predicted to exhibit similar features. Due to the experimental difficulties when approaching the proton drip-line, the lightest Po isotope for which in-beam γ-ray data exists prior this work has been 192Po. Since shape coexistence should be most pronounced at the neutron mid-shell (N=104), information about the excited states in lighter Po isotopes would be valuable in verifying the existence and possibly understanding the origin of the phenomenon in these nuclei. In the present work the recoil decay tagging method has been used to study excited states in the neutron deficient isotopes 190,191Po. Prompt γ-rays were detected with the Jurosphere Ge detector array coupled to the gas- filled separator RITU. The 191Po nuclei were produced in the 142Nd(52Cr,3n)191Po reaction at a bombarding energy of 240MeV. The observed prompt γ-rays correlated with the α-decay of the 191mPo 13/2+ state were placed in two cascades. Similar sequences have been observed in 193,195Po and presumably correspond to favoured and unfavoured states in the vi13 band. The unfavoured states are lowered below the favoured ones, resulting in a strongly coupled scheme which suggests oblate deformation. In a separate experiment the 142Nd(52Cr,4n)190Po reaction was used at higher beam energy. The production cross-section was approximately 200nb. Four prompt α-transitions correlated with the 190Po α-decay were observed and intepreted to form a cascade of E2 transitions up to spin 8+. In comparison to the heavier even Po isotopes, a drop in 6+ and 8+ energies is observed. This suggest an onset of prolate deformation in light Po isotopes as predicted by Oros et al. The results will be discussed in the framework of intruder states (author)

  16. Insights in the laser induced breakdown spectroscopy signal generation underwater using dual pulse excitation — Part II: Plasma emission intensity as a function of interpulse delay

    International Nuclear Information System (INIS)

    Influence of time delay between two laser pulses on the LIBS (laser induced breakdown spectroscopy) signal inside liquids was investigated and the results are compared with data from literature. Plasma was produced by laser ablation (LA) of aluminum inside water and its emission after the second laser pulse was characterized by spectrally and time resolved detection. Light propagation through the vapor bubble formed by the first laser pulse was studied by measurements of beam scattering and transmission. Optical absorption by the evolving bubble is not significant, but its growth is accompanied by lowering of its refraction index nb with respect to surrounding liquid; this effect increases defocusing both of the incident beam and of the out-coming plasma radiation. Collection efficiency of the secondary plasma emission rapidly degrades with the cavity growth, but close to its full expansion the LIBS signal partially recovers through Snell's reflections at the liquid–vapor interface, which produce a bright spot close to the bubble center. Such a light redistribution allows detecting of the emission from external plasma volume, otherwise deflected out of the collection system. Except for strong line transitions from the main sample constituents, self-absorbed inside the high-pressure cavity, we observed the highest LIBS signal when sending the second pulse well before the bubble is fully expanded. Transitions of the pressure wave through the focal volume, formed by the first laser pulse and reflected from the cell's walls and sample back-plane, enhances the LIBS signal importantly. The measured lifetime of the secondary plasma rapidly decreases with the bubble expansion. Here, we also discuss the optimization of the optical collection system and some analytical aspects of double-pulse (DP) LIBS inside liquids. - Highlights: ► DP-LIBS signal dependence in liquids on interpulse delay is fully explained. ► Formation and detection of the plasma depend on optical

  17. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  18. Determination of Cr(VI) and Cr(III) in urine and dextrose by inductively coupled plasma emission spectroscopy

    Science.gov (United States)

    Mianzhi, Zhuang; Barnes, Ramon M.

    The determination of Cr(VI) and Cr(III) in human urine and in commercial dextrose solution is performed by induclively coupled plasma-atomic emission spectroscopy after selective preconcentration of the chromium species at different pH values by poly(dithiocarbamate) and poly(acrylamidoxime) chelating resins. The chelating properties of these resins with chromium, including the kinetics of uptake and removal of Cr(III), and the influence of matrix concentrations were evaluated. Chromium in human urine was found to exist exclusively as Cr(III).

  19. Optical emission spectroscopy analysis for Ge2Sb2Te5 etching endpoint detection in HBr/He plasma

    Science.gov (United States)

    Li, Juntao; Liu, Bo; Song, Zhitang; Feng, Gaoming; Wu, Guanping; He, Aodong; Yang, Zuoya; Zhu, Nanfei; Xu, Jia; Ren, Jiadong; Feng, Songlin

    In the fabrication of phase change memory devices, HBr/He gas is employed in patterning Ge2Sb2Te5 (GST) because it is damage free to GST sidewall. Accurate and reproducible endpoint detection methods are necessary in this etching process. In-situ optical emission spectroscopy (OES) is collected and analyzed to control the GST etching process due to its non-invasiveness. By analyzing the light emitted from plasma, we report an effective etch endpoint detection method for GST etching process is developed and the results are also confirmed using scanning electron micrographs.

  20. Progress of the spectroscopy research platform at the Shanghai electron beam ion trap

    Science.gov (United States)

    Hutton, Roger; Yao, Ke; Xiao, Jun; Yang, Yang; Lu, Di; Shen, Yang; Fu, Yunqing; Zhang, Xuemei; Zou, Yaming

    2009-04-01

    In this report we will focus on spectrometer development, spectroscopic studies and a few other recent developments at the Shanghai Electron Beam Ion Trap, EBIT laboratory. Currently the Shanghai EBIT has three spectrometers covering totally the wavelength region of 1 to 10000 Å. Two of these instruments are home made. A flat crystal spectrometer covers the wavelength range of around 1 - 20 Å while a flat field instrument covers the range of around 20 - 400 Å. The 3rd instrument is a commercial McPherson 225 normal incidence spectrometer. All spectrometers employ CCD cameras for photon detection. The Shanghai EBIT is also equipped with high purity Germanium detectors for, amongst other things, dielectronic recombination studies and time evolution studies of ion distributions. To back up these experimental studies computer codes have been developed for calculation of charge state balances etc. Parallel to the experimental program we have also developed experience at running a number of atomic structure codes (MCHF, MCDF, FAC) for various systems, e.g. the M3 decay of the 3d94s 3D3 for Ni-like ions.

  1. In-beam spectroscopy of the Kπ = 0- bands in 230-236U

    International Nuclear Information System (INIS)

    The Kπ = 0- bands in even uranium nuclei were studied in the compound reactions 231Pa(p,2n)230U, 230,232Th(α,2n)232,234U and 236U(d,pn)236U. In-beam γ-rays were measured in coincidence with conversion-electrons, which were detected with an iron-free orange spectrometer. The negative-parity levels are observed up to intermediate spins (I-). In addition, the 1- and 3- levels in 230U were confirmed by a decay study with an isotope separated 230Pa source. For the heavier isotopes (A > or approx. 232) the properties of the Kπ = 0- bands (energies and γ-branchings) are consistent with a vibrational character of these bands. For 230U the Kπ = 0- band lies at rather low energy (E(1-) = 367 keV), and the level spacings within this band are very similar to those of the isotones 228Th and 226Ra, which might indicate the onset of a stable octupole deformation. (orig.)

  2. Investigation of hyperfine structures of spectral lines of singly ionized praseodymium using fourier transform spectrum, saturation spectroscopy and collinear laser ion beam spectroscopy

    International Nuclear Information System (INIS)

    The hyperfine (hf) structure splitting of a fine structure energy level is caused by the interaction of the electromagnetic nuclear moments with the electromagnetic moments of the electron shell. The splitting of the hf structure is determined by the magnetic dipole interaction constant A and an additional small shift in the hf levels is determined by the quadrupole interaction constant B. Praseodymium (Pr) has five electrons in the outermost shells. The coupling of five (Pr I) or four (Pr II) electrons produces a large number of fine structure levels resulting in a dense and complicated optical spectrum. For the classification of spectral lines, precise values of hf constants and energy values of the levels involved in the transitions are required. This work is divided into three parts: In the first part, the spectral lines of Pr II are analyzed using a high resolution Fourier transform spectrum in the spectral range from 3260 to 11700 Å. Transition wavelengths of Pr II spectral lines are re-determined and then, using these accurate transition wavelengths, the energy values of the levels involved in the transitions are improved. Wavelengths for 477 spectral lines and energy values for 227 known levels of Pr II are improved. Investigation of narrow hf structures needs a reduction of the Doppler broadening of the investigated lines. The hf structures are experimentally investigated using two methods of Doppler reduced spectroscopy. In the second part of this work, the hf structures of the Pr II spectral lines are investigated in a hollow cathode discharge lamp using inter-modulated laser induced fluorescence spectroscopy. Using this method 6 Pr II transitions are investigated and a spectral width of about ca. 200 MHz was achieved. The main research work is carried out in the third part. The Pr II spectral lines are investigated using the high resolution method of Collinear Laser Ion Beam Spectroscopy (CLIBS). The CLIBS measurements are performed using the Marburg

  3. Study of the trace tritium content in deuterium plasmas of the JET tokamak based on neutron emission spectroscopy measurements

    International Nuclear Information System (INIS)

    This thesis describes a study of the evolution of the trace tritium content in the JET tokamak. The study is based on measurements of the neutron emission, which were performed with the magnetic proton recoil (MPR) spectrometer. Data analysis procedures used to extract the results are described in some detail. The thesis also describes a simplified theoretical model to calculate the absolute tritium concentration with a comparison to the experimental results. The present study covers the time period 1996-2000 and the evolution of neutron emission spectroscopy (NES) results are compared with information from related diagnostic sources, and used to discuss the important issue of how tritium is retained in the JET tokamak

  4. Radio imaging spectroscopy of synchrotron emission associated with a CME on the 14th of August 2010

    Science.gov (United States)

    Bain, Hazel; Krucker, S.; Saint-Hilaire, P.; Raftery, C.

    2013-07-01

    We present Nancay Radioheliograph observations of a moving type IV solar radio burst which occurred in association with a CME on the 14th of August 2010. The event was well observed at extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, the SWAP instrument onboard Proba2 and by the LASCO white light coronograph. The burst emission was found to be cospatial with the core of the CME. Using radio imaging spectroscopy we are able to characterize the underlying electron distribution and plasma parameters within the source. Fitted spectra reveal a clear power law component consistent with optically thin synchrotron emission from accelerated electrons trapped in the erupting flux rope. As is often observed in type IV bursts, polarization measurements show the source to be moderately polarized during the peak of the burst, before steadily increasing to around 70% as the brightness temperature of the burst decays.

  5. Effect of Surface Hydrogen Coverage on Field Emission Properties of DiamondFilms Investigated by High-Resolution Electron Energy Loss Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Guang; XIONG Yan-Yun; LIN Zhang-Da; FENG Ke-An; GU Chang-Zhi; JIN Zeng-Sun

    2000-01-01

    The influence of surface hydrogen coverage on the electron field emission of diamond films was investigated by high-resolution electron energy loss spectroscopy. It was found that hydrogen plasma treatment increased the surface hydrogen coverage while annealing caused hydrogen desorption and induced surface reconstruction. Field electron emission measurements manifested that increase of surface hydrogen coverage could improve the field emission properties, due to the decrease of electron affinity of the diamond .surface hy hvdrogen adsorption.

  6. Evaluation of the electron beam flue gas treatment process to remove SO2 and NOx emission from coal thermal power plants in Turkey

    International Nuclear Information System (INIS)

    In this study, both the current energy consumption and production and SO2 and NOx emission in Turkey is analyzed. The electron beam FGT is compared with preferred limestone/gypsum wet-scrubbing process and evaluated for each power plant. As shown, the investments and the operational costs of electron beam FGT are higher than preferred conventional FGD except 1x210 MWe Orhaneli plant. As a result, if investment and operational costs are reduced, in the future the electron beam FGT may be the solution for reduction of both SO2 and NOx emission from small to mid-sized coal thermal power plants

  7. Application of optical emission spectroscopy for He I considering the spatial structure of radiation trapping in MAP-II divertor simulator

    International Nuclear Information System (INIS)

    The He I optical emission spectroscopy that considers the spatial structure of radiation trapping was proposed by us and was applied to a MAP-II divertor simulator. The spatial distribution of the optical escape factor was calculated from the n 1P (n≥3) state profiles measured by visible spectroscopy. The profile of 2 1P, which is immeasurable by visible spectroscopy, needs to be broader than that of the 3 1P state. The sensitivity of the 2 1P profile to the Te value estimated by He I spectroscopy is investigated.

  8. In situ proton-induced X-ray emission and Auger electron spectroscopy study of titanium and niobium implantation of iron films

    International Nuclear Information System (INIS)

    Implantation of 190 keV titanium and niobium ions into iron films 200 nm thick electron beam deposited onto polished Si(100) substrates has been investigated. During the course of implantation of the iron films, proton-induced X-ray emission was used to measure the instantaneous film thickness and the total retained dose, whereas Auger electron spectroscopy was used to determine the surface concentrations of the implanted species and the reactive elements. Implantations were carried out both under ultrahigh vacuum conditions and with the chamber backfilled with CO to a pressure of 1 X 10-6 Torr. Elemental sputtering yields were measured for iron and the implanted elements as a function of fluence. The results showed that, for titanium implantation, the addition of CO to the target chamber significantly reduced the sputtering yield of the substrate and increased the retained dose that could be achieved. For niobium implantation the addition of CO to the chamber reduced the substrate sputtering yield, but not to the same degree as observed for titanium, and did not alter the total retained dose that could be achieved. (Auth.)

  9. Double pulse laser induced breakdown spectroscopy: Experimental study of lead emission intensity dependence on the wavelengths and sample matrix

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli S, V.; Martinez L, M.A.; Fernandez C, A.J. [Laboratorio de Espectroscopia Laser, Escuela de Quimica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, DC 1020 (Venezuela, Bolivarian Republic of); Gonzalez, J.J.; Mao, X.L. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Russo, R.E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: RERusso@lbl.gov

    2009-02-15

    Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm. Two series of standard reference materials from the National Institute of Standards and Technology (NIST) and one series from the British Chemical Standards (BCS) were used for these experiments. Calibration curves for lead ablated from NIST 626-630 ('Zn{sub 95}Al{sub 4}Cu{sub 1}') provided higher sensitivity (slope) than those calibration curves produced from NIST 1737-1741 ('Zn{sub 99.5}Al{sub 0.5}') and with the series BCS 551-556 ('Cu{sub 87}Sn{sub 11}'). Similar trends between lead emission intensity (calibration curve sensitivities) and reported variations in plasma temperatures caused by the differing ionization potentials of the major and minor elements in these samples were established.

  10. Development of a PIXE (Particle Induced X-ray Emission) analysis device using an extracted proton beam

    International Nuclear Information System (INIS)

    The experimental device described allows the extention of the PIXE (Particle Induced X-ray Emission) method to the analysis, by means of proton beams, of solid or liquid samples, which can not be analyzed under vacuum conditions. The homogeneity of the surfaces to be analysed and elements (in the atmosphere) which absorb X-rays must be taken into account. Liquid samples do not need special care. The results show that: at high energies, the extracted beam sensibility is of the same order of magnitude as those obtained under vacuum; at low energies, the performance under vacuum conditions is better. The particles energy losses, at the exit membrane and in the outer atmosphere, decrease the X-rays production efficiency

  11. Diagnosis of iso-octane combustion in a shock tube by emission spectroscopy

    Science.gov (United States)

    Zhang, Changhua; Tang, Hongchang; Zhang, Chuanzhao; Zhao, Yan; Li, Ping; Li, Xiangyuan

    2013-01-01

    Ultraviolet-Visible emission from iso-octane combustion was measured behind reflected shock waves. OH∗, CH∗ and C2∗ were recorded as the major intermediate species. When the equivalence ratio increases, the emission intensity ratio of OH∗/CH∗ decreases and that of C2∗/OH∗ increases. Rotational and vibrational temperatures were determined by comparing the measured emission spectra with the simulated ones of CH∗ and C2∗. The rotational temperatures are in good agreement with the calculated adiabatic flame temperatures and the vibrational temperatures are significantly higher. Furthermore, ignition delay times were obtained to provide a database for the validation of the kinetic mechanism.

  12. The Development of Cavity Ringdown Spectroscopy as a Toxic Metal Continuous Emission Monitor

    International Nuclear Information System (INIS)

    Innovative program to explore the viability of using Cavity Ringdown Spectroscopy (CRDS) for trace analysis and monitoring of remediation processes for hazardous and radioactive wastes. Cavity ringdown spectroscopy is a measurement of the rate of absorption of a sample within a closed optical cavity rather than the standard measurement of the absorbed signal strength over a given sample path. It is a technique capable of providing ultra-sensitive absorption measurements in hostile environments using commercially available easy-to-use pulsed lasers. The inherent high sensitivity stems from both the long effective sample pathlengths possible and the relaxed constraints on the accuracy of the measurement of the cavity decay time

  13. Amplified spontaneous emission in active channel waveguides produced by electron-beam lithography in LiF crystals

    International Nuclear Information System (INIS)

    In this letter we report the observation of amplified spontaneous emission of the red light from LiF:F2 centers in active channel waveguides realized by electron-beam lithography in lithium fluoride crystals. Low pumping power densities have been used in quasi-continuous-wave regime at room temperature; the appreciable values of the gain coefficients, 4.67 cm-1 with an exciting power density of 0.31 W/cm2 at 458 nm, make this material a good candidate for the realization of active integrated optical devices. [copyright] 2001 American Institute of Physics

  14. The neutron emission induced by the radioactive nuclear beam 17N on targets 9Be and 197Au

    International Nuclear Information System (INIS)

    The neutron energy spectra emitted in the reactions of 33.4MeV/u 17N on 9Be and 197Au targets have been measured at different angles with the time of flight method. The angular distributions were composed of two components: one focused into a narrow angle range around the beam direction and another extended over a large angle region. Integrating the angular distribution, the obtained total cross sections of neutron emission were (15.2 +- 1.7) x 10-28m2 and (120 +- 20) x 10-28m2 barns respectively for 9Be and 197Au targets

  15. High resolution X-ray emission spectroscopy of water and aqueous ions using the micro-jet technique

    International Nuclear Information System (INIS)

    Graphical abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl2. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the study of biochemical systems in physiological media. - Abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl2. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the

  16. High resolution X-ray emission spectroscopy of water and aqueous ions using the micro-jet technique

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Kathrin M.; Koennecke, Rene; Ghadimi, Samira; Golnak, Ronny [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Soldatov, Mikhail A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu 344090 (Russian Federation); Hodeck, Kai F. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Soldatov, Alexander [Research Center for Nanoscale Structure of Matter, Southern Federal University, Sorge 5, Rostov-na-Donu 344090 (Russian Federation); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Freie Universitaet Berlin, FB Physik, Arnimallee 14, D-14195 Berlin (Germany)

    2010-11-25

    Graphical abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl{sub 2}. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the way for the study of biochemical systems in physiological media. - Abstract: Soft X-ray absorption (XA) and emission (XE) spectroscopy is a powerful method for probing the local electronic structure of light elements (e.g. C, O, N, S) and transition metals, which are all of importance for biochemical systems. Here, we report for the first time on the XE spectra of a liquid micro-jet sample in a vacuum environment. We developed a high resolution X-ray emission spectrometer and recorded the spectra of pure water in full agreement with those of the literature, as well as of an aqueous solution of NiCl{sub 2}. For the latter system, ground state Hartree-Fock calculations using a self-consistent reaction field (SCRF) approach were carried out to specify the nature of the d-occupied orbital. Our results confirm the dark-channel-fluorescence-yield mechanism that we recently proposed for the case of metal ions in aqueous solutions. The ability to record absorption and emission spectra of an aqueous liquid-jet opens the

  17. IFU spectroscopy of 10 early-type galactic nuclei - II. Nuclear emission line properties

    Science.gov (United States)

    Ricci, T. V.; Steiner, J. E.; Menezes, R. B.

    2014-05-01

    Although it is well known that massive galaxies have central black holes, most of them accreting at low Eddington ratios, many important questions still remain open. Among them are the nature of the ionizing source, the characteristics and frequencies of the broad-line region and of the dusty torus. We report observations of 10 early-type galactic nuclei, observed with the Gemini Multi Object Spectrograph in integral field unit mode, installed on the Gemini South telescope, analysed with standard techniques for spectral treatment and compared with results obtained with principal component analysis Tomography (Paper I). We performed spectral synthesis of each spaxel of the data cubes and subtracted the stellar component from the original cube, leaving a data cube with emission lines only. The emission lines were decomposed in multi-Gaussian components. We show here that, for eight galaxies previously known to have emission lines, the narrow-line region can be decomposed in two components with distinct line widths. In addition to this, broad Hα emission was detected in six galaxies. The two galaxies not previously known to have emission lines show weak Hα+[N II] lines. All 10 galaxies may be classified as low-ionization nuclear emission regions in diagnostic diagrams and seven of them have bona fide active galactic nuclei with luminosities between 1040 and 1043 erg s-1. Eddington ratios are always <10-3.

  18. Ultrafast soft X-ray emission spectroscopy of surface adsorbates using an X-ray free electron laser

    International Nuclear Information System (INIS)

    Highlights: •Development of the soft X-ray spectroscopy setup to probe surfaces using free electron laser. •Probing surface chemical reactions using free electron laser. •Optical laser pump and soft X-ray probe study on a sub-picosecond timescale. -- Abstract: We report on an experimental system designed to probe chemical reactions on solid surfaces on a sub-picosecond timescale using soft X-ray emission spectroscopy at the Linac Coherent Light Source (LCLS) free electron laser (FEL) at the SLAC National Accelerator Laboratory. We analyzed the O 1s X-ray emission spectra recorded from atomic oxygen adsorbed on a Ru(0 0 0 1) surface at a synchrotron beamline (SSRL, BL13-2) and an FEL beamline (LCLS, SXR). We have demonstrated conditions that provide negligible amount of FEL induced damage of the sample. In addition we show that the setup is capable of tracking the temporal evolution of electronic structure during a surface reaction of submonolayer quantities of CO molecules desorbing from the surface

  19. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around $<10$-Day-Old Type II Supernovae

    CERN Document Server

    Khazov, D; Gal-Yam, A; Manulis, I; Rubin, A; Kulkarni, S R; Arcavi, I; Kasliwal, M M; Ofek, E O; Cao, Y; Perley, D; Sollerman, J; Horesh, A; Sullivan, M; Filippenko, A V; Nugent, P E; Howell, D A; Cenko, S B; Silverman, J M; Ebeling, H; Taddia, F; Johansson, J; Laher, R R; Surace, J; Rebbapragada, U D; Wozniak, P R; Matheson, T

    2015-01-01

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra ($\\leq 10$ days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 Type II SNe showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14\\% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18\\% of SNe~II observed at ages $<5$ days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum which is similar to that of a black body, without any emission or absorption signa...

  20. Ultrafast soft X-ray emission spectroscopy of surface adsorbates using an X-ray free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, T.; Anniyev, T. [SIMES, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Beye, M. [SIMES, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Coffee, R. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Dell’Angela, M. [University of Hamburg and Center for Free Electron Laser Science, Luruper Chaussee 149, D-22761 Hamburg (Germany); Föhlisch, A. [Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany); Gladh, J. [Department of Physics, AlbaNova University Center, Stockholm University, SE-10691 (Sweden); Kaya, S. [SIMES, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Krupin, O. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); and others

    2013-04-15

    Highlights: •Development of the soft X-ray spectroscopy setup to probe surfaces using free electron laser. •Probing surface chemical reactions using free electron laser. •Optical laser pump and soft X-ray probe study on a sub-picosecond timescale. -- Abstract: We report on an experimental system designed to probe chemical reactions on solid surfaces on a sub-picosecond timescale using soft X-ray emission spectroscopy at the Linac Coherent Light Source (LCLS) free electron laser (FEL) at the SLAC National Accelerator Laboratory. We analyzed the O 1s X-ray emission spectra recorded from atomic oxygen adsorbed on a Ru(0 0 0 1) surface at a synchrotron beamline (SSRL, BL13-2) and an FEL beamline (LCLS, SXR). We have demonstrated conditions that provide negligible amount of FEL induced damage of the sample. In addition we show that the setup is capable of tracking the temporal evolution of electronic structure during a surface reaction of submonolayer quantities of CO molecules desorbing from the surface.