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Sample records for 2 20 kev range

  1. Characterisation of a counting imaging detector for electron detection in the energy range 10-20 keV

    Moldovan, G., E-mail: grigore.moldovan@materials.ox.ac.uk [University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH (United Kingdom); Sikharulidze, I. [Leiden University, Leiden Institute of Chemistry, P.O. Box 9502, 2300RA Leiden (Netherlands); Matheson, J.; Derbyshire, G. [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Kirkland, A.I. [University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH (United Kingdom); Abrahams, J.P. [Leiden University, Leiden Institute of Chemistry, P.O. Box 9502, 2300RA Leiden (Netherlands)

    2012-07-21

    As part of a feasibility study into the use of novel electron detector for X-ray photoelectron emission microscopes (XPEEM) and related methods, we have characterised the imaging performance of a counting Medipix 2 readout chip bump bonded to a Silicon diode array sensor and directly exposed to electrons in the energy range 10-20 keV. Detective Quantum Efficiency (DQE), Modulation Transfer Function (MTF) and Noise Power Spectra (NPS) are presented, demonstrating very good performance for the case of electrons with an energy of 20 keV. Significant reductions in DQE are observed for electrons with energy of 15 keV and less, down to levels of 20% for electrons of 10 keV.

  2. Investigation of multilayer X-ray optics for 6 keV to 20 keV energy range

    Oberta, Peter; Platonov, Y.; Flechsig, U.

    2012-01-01

    Roč. 19, č. 5 (2012), s. 675-681. ISSN 0909-0495 Institutional research plan: CEZ:AV0Z10100522 Keywords : X-ray optics * multilayer * energy resolution Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.186, year: 2012 http://journals.iucr.org/s/issues/2012/05/00/issconts.html

  3. Characterisation of a detector based on microchannel plates for electrons in the energy range 10-20 keV

    Moldovan, G. [Department of Materials, University of Oxford, Parks Road, Oxford, Oxon OX1 3PH (United Kingdom)], E-mail: grigore.moldovan@materials.ox.ac.uk; Matheson, J.; Derbyshire, G. [Rutherford Appleton Laboratory, Science and Technology Facilities Council, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Kirkland, A. [Department of Materials, University of Oxford, Parks Road, Oxford, Oxon OX1 3PH (United Kingdom)

    2008-11-11

    As part of a feasibility study into the use of novel electron detectors for an X-ray photoelectron emission microscope (XPEEM), we have characterised a detector based on microchannel plates (MCPs), a phosphor screen and a CCD camera. For XPEEM, an imaging detector is required for electrons in the energy range 10-20 keV. This type of detector is a standard fitment on commercial instruments and we have studied its performance in some detail in order to provide a baseline against which to evaluate future detector technologies. We present detective quantum efficiency (DQE), noise power spectrum (NPS) and modulation transfer function (MTF) measurements of a commercial detector, in the energy range of interest, as a function of the detector bias voltage.

  4. QUIET-TIME INTERPLANETARY {approx}2-20 keV SUPERHALO ELECTRONS AT SOLAR MINIMUM

    Wang, Linghua [Department of Geophysics, Peking University, 100871 Beijing (China); Lin, Robert P.; Salem, Chadi; Pulupa, Marc; Larson, Davin E.; Luhmann, Janet G. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Yoon, Peter H., E-mail: wanglhwang@gmail.com [School of Space Research, Kyung Hee University, Yongin, Gyeonggi (Korea, Republic of)

    2012-07-01

    We present a statistical survey of {approx}2-20 keV superhalo electrons in the solar wind measured by the SupraThermal Electron instrument on board the two STEREO spacecraft during quiet-time periods from 2007 March through 2009 March at solar minimum. The observed superhalo electrons have a nearly isotropic angular distribution and a power-law spectrum, f{proportional_to}v{sup -{gamma}}, with {gamma} ranging from 5 to 8.7, with nearly half between 6.5 and 7.5, and an average index of 6.69 {+-} 0.90. The observed power-law spectrum varies significantly on a spatial scale of {approx}>0.1 AU and a temporal scale of {approx}>several days. The integrated density of quiet-time superhalo electrons at 2-20 keV ranges from {approx}10{sup -8} cm{sup -3} to 10{sup -6} cm{sup -3}, about 10{sup -9}-10{sup -6} of the solar wind density, and, as well as the power-law spectrum, shows no correlation with solar wind proton density, velocity, or temperature. The density of superhalo electrons appears to show a solar-cycle variation at solar minimum, while the power-law spectral index {gamma} has no solar-cycle variation. These quiet-time superhalo electrons are present even in the absence of any solar activity-e.g., active regions, flares or microflares, type III radio bursts, etc.-suggesting that they may be accelerated by processes such as resonant wave-particle interactions in the interplanetary medium, or possibly by nonthermal processes related to the acceleration of the solar wind such as nanoflares, or by acceleration at the CIR forward shocks.

  5. Search for galactic sources of X-ray bursts with scintillation spectrometers of the Kosmos-856 satellite in the energy range of 20-320 keV

    Search for galactic sources of X-pay bursts with a scintillation spectrometer of ''Kosmos-856'' satellite has given a negative result. During 21 hours of observations with two independent detectors not one burst of X-rays with the energy flux P 2x10-7 erg/cm2 has been found in the energy range 20-320 keV and duration 10s. This result disagrees with the data obtained with the ''Kosmos-428'' satellite

  6. Adjustment of a goniometer for X-rays optics calibration in the spectral range 1.5-20 KeV

    The aim of this memoir is the adjustment of a (θ, 2θ) goniometer coupled to X-rays source to calibrate mirrors (single layers like C, Ni, Au, etc... and multilayers like C/W, Si/W, etc...) in the spectral range 1.5 - 20 keV. For each kind of tested optics the adjustment of the goniometer include the procedure alignment of the different components (X-ray source, collimation slits, optics, detectors) and the first reflectivity measurements. Those measurements are compared those realized at LURE, using synchrotron radiation provided by SUPER ACO storage ring, and to a theoretical simulation

  7. Multilayer optics for monochromatic high-resolution X-ray imaging diagnostic in a broad photon energy range from 2 keV to 22 keV

    The “Commissariat à l’énergie atomique et aux énergies alternatives” (CEA) studies and designs advanced X-ray diagnostics to probe dense plasmas produced at the future Laser MegaJoule (LMJ) facility. Mainly for X-ray imaging with high spatial resolution, different types of multilayer mirrors were developed to provide broadband X-ray reflectance at grazing incidence. These coatings are deposited on two toroidal mirror substrates that are then mounted into a Wolter-type geometry (working at a grazing angle of 0.45°) to realize an X-ray microscope. Non-periodic (depth graded) W/Si multilayer can be used in the broad photon energy range from 2 keV to 22 keV. A third flat mirror can be added for the spectral selection of the microscope. This mirror is coated with a Mo/Si multilayer for which the d-spacing varies in the longitudinal direction to satisfy the Bragg condition within the angular acceptance of the microscope and also to compensate the angular dispersion due to the field of the microscope. We present a study of such a so-called Göbel mirror which was optimized for photon energy of 10.35 keV. The three mirrors were coated using magnetron sputtering technology by Xenocs SA. The reflectance in the entire photon energy range was determined in the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the synchrotron radiation facility BESSY II in Berlin

  8. Effects of uranium bombardment by 20-40 KeV argon ions, Annex 2

    This paper shows the results of argon ions interaction with the polycrystal natural uranium. Thin foil of uranium about 200 μ was bombarded by 20-40 KeV argon ions. Coefficients of cathode scattering δ and secondary electrons emission γ were measured, during the process A+ →U. The foil was then studied by transmission method and method of single step replica using an electron microscope

  9. Observations of the Cyg X-1 and Cyg X-2 sources with X-ray spectrometers of the Kosmos-856 satellite in the energy range of 20-320 keV

    The data of observations of CYG X-1and CYG X-2 X-ray sources carried out with two scintillation spectrometers of ''Kosmos-856'' satellite are given. The results of measurements of the spectrum of CYG X-1 source are compared with those obtained in the experiment of OSO-7 satelllite and balloon experiments. The intensity of CYG X-2 source during observations was at the threshold of reliable determination

  10. Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

    Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

    2013-04-01

    Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

  11. Study on absolute sensitivity of X-ray electron-optical converter in the energy range of 7-20 keV

    Absolute spectral sensitivity of X-ray electron-optical converter (XREOC) with the beryllium window and a microchannel plate as a converting and amplifying element for the 7-20 keV X-ray range, was measured. Measurements were performed in the VEhPP-3M storage ring synchrotron radiation channel. It is shown that in the energy range indicated the ratio of photon number in the blue spectrum region at the XREOC outlet to the number of X-ray quanta at the inlet grows from 1200 up to 2200 photons per a quantum. Sensitivity change over the XREOC operating field is investigated

  12. Neutron Total Cross Sections of 235U From Transmission Measurements in the Energy Range 2 keV to 300 keV and Statistical Model Analysis of the Data

    The average 235U neutron total cross sections were obtained in the energy range 2 keV to 330 keV from high-resolution transmission measurements of a 0.033 atom/b sample.1 The experimental data were corrected for the contribution of isotope impurities and for resonance self-shielding effects in the sample. The results are in very good agreement with the experimental data of Poenitz et al.4 in the energy range 40 keV to 330 keV and are the only available accurate experimental data in the energy range 2 keV to 40 keV. ENDF/B-VI evaluated data are 1.7% larger. The SAMMY/FITACS code 2 was used for a statistical model analysis of the total cross section, selected fission cross sections and data in the energy range 2 keV to 200 keV. SAMMY/FITACS is an extended version of SAMMY which allows consistent analysis of the experimental data in the resolved and unresolved resonance region. The Reich-Moore resonance parameters were obtained 3 from a SAMMY Bayesian fits of high resolution experimental neutron transmission and partial cross section data below 2.25 keV, and the corresponding average parameters and covariance data were used in the present work as input for the statistical model analysis of the high energy range of the experimental data. The result of the analysis shows that the average resonance parameters obtained from the analysis of the unresolved resonance region are consistent with those obtained in the resolved energy region. Another important result is that ENDF/B-VI capture cross section could be too small by more than 10% in the energy range 10 keV to 200 keV

  13. Neutron Total Cross Sections of {sup 235}U From Transmission Measurements in the Energy Range 2 keV to 300 keV and Statistical Model Analysis of the Data

    Derrien, H.; Harvey, J.A.; Larson, N.M.; Leal, L.C.; Wright, R.Q.

    2000-05-01

    The average {sup 235}U neutron total cross sections were obtained in the energy range 2 keV to 330 keV from high-resolution transmission measurements of a 0.033 atom/b sample.1 The experimental data were corrected for the contribution of isotope impurities and for resonance self-shielding effects in the sample. The results are in very good agreement with the experimental data of Poenitz et al.4 in the energy range 40 keV to 330 keV and are the only available accurate experimental data in the energy range 2 keV to 40 keV. ENDF/B-VI evaluated data are 1.7% larger. The SAMMY/FITACS code 2 was used for a statistical model analysis of the total cross section, selected fission cross sections and data in the energy range 2 keV to 200 keV. SAMMY/FITACS is an extended version of SAMMY which allows consistent analysis of the experimental data in the resolved and unresolved resonance region. The Reich-Moore resonance parameters were obtained 3 from a SAMMY Bayesian fits of high resolution experimental neutron transmission and partial cross section data below 2.25 keV, and the corresponding average parameters and covariance data were used in the present work as input for the statistical model analysis of the high energy range of the experimental data. The result of the analysis shows that the average resonance parameters obtained from the analysis of the unresolved resonance region are consistent with those obtained in the resolved energy region. Another important result is that ENDF/B-VI capture cross section could be too small by more than 10% in the energy range 10 keV to 200 keV.

  14. NEUTRON TOTAL CROSS SECTIONS OF 235U FROM TRANSMISSION MEASUREMENTS IN THE ENERGY RANGE 2 keV to 300 keV AND STATISTICAL MODEL ANALYSIS OF THE DATA

    Derrien, H.

    2000-05-22

    The average {sup 235}U neutron total cross sections were obtained in the energy range 2 keV to 330 keV from high-resolution transmission measurements of a 0.033 atom/b sample. The experimental data were corrected for the contribution of isotope impurities and for resonance self-shielding effects in the sample. The results are in very good agreement with the experimental data of Poenitz et al. in the energy range 40 keV to 330 keV and are the only available accurate experimental data in the energy range 2 keV to 40 keV. ENDF/B-VI evaluated data are 1.7% larger. The SAMMY/FITACS code was used for a statistical model analysis of the total cross section, selected fission cross sections and {alpha} data in the energy range 2 keV to 200 keV. SAMMY/FITACS is an extended version of SAMMY which allows consistent analysis of the experimental data in the resolved and unresolved resonance region. The Reich-Moore resonance parameters were obtained from a SAMMY Bayesian fits of high resolution experimental neutron transmission and partial cross section data below 2.25 keV, and the corresponding average parameters and covariance data were used in the present work as input for the statistical model analysis of the high energy range of the experimental data. The result of the analysis shows that the average resonance parameters obtained from the analysis of the unresolved resonance region are consistent with those obtained in the resolved energy region. Another important result is that ENDF/B-VI capture cross section could be too small by more than 10% in the energy range 10 keV to 200 keV.

  15. Observations of the scatter-free solar-flare electrons in the energy range 20-1000 keV

    Wang, J. R.; Fisk, L. A.; Lin, R. P.

    1971-01-01

    Observations of the scatter-free electron events from solar active region McMath No. 8905 are presented. The measurements were made on Explorer 33 satellite. The data show that more than 80% of the electrons from these events undergo no or little scattering and that these electrons travel only approximately 1.5 a.u. between the sun and the earth. The duration of these events cannot be accounted fully by velocity dispersion alone. It is suggested that these electrons could be continuously injected into interplanetary medium for a time interval of approximately 2 to 3 minutes. Energy spectra of these electrons are discussed.

  16. Scintillation spectrometers of the Kosmos-856 and Kosmos-914 satellites for studies of galactic x-rays in the energy range of 20-320 keV

    Scintillation spectrometers used in the studies of space hard X-rays in the energy range of 20-300 keV on the ''Kosmos-856'' and ''Kosmos-914'' satellites are described. A combined scintillation detector, consisting of NaI(Tl) (the height is 10 mm) and CsI(Tl) (the height is 35 mm), has been used in each of the spectrometers. The diameter of each scintillating crystal is 80 mm. A crystal of NaI(Tl) is used as a spectotrometric crystal. A crystal of CsI(Tl) is used as an active shield for the NaI(Tl) crystal To exclude recording of charged particles the detector is surrounded with a plastic scintillator. The use of a combined scintillation detector allowed to decrease the background considerably and thus to increase significantly the sensitivity of the instrument in comparison with the similar spectrometer which was used in the ''Kosmos-428'' satellite

  17. THE EMISSION OF CYGNUS X-1: OBSERVATIONS WITH INTEGRAL SPI FROM 20 keV TO 2 MeV

    We report on Cyg X-1 observations performed by the SPI telescope on board the INTEGRAL mission and distributed over more than 6 years. We investigate the variability of the intensity and spectral shape of this peculiar source in the hard X-ray domain, and more particularly up to the MeV region. We first study the total averaged spectrum which presents the best signal-to-noise ratio (4 Ms of data). Then, we refine our results by building mean spectra by periods and gathering those of similar hardness. Several spectral shapes are observed with important changes in the curvature between 20 and 200 keV, even at the same luminosity level. In all cases, the emission decreases sharply above 700 keV, with flux values above 1 MeV (or upper limits) well below the recently reported polarized flux, while compatible with the MeV emission detected some years ago by the Compton Gamma-ray Observatory/COMPTEL. Finally, we take advantage of the spectroscopic capability of the instrument to seek for spectral features in the 500 keV region with negative results for any significant annihilation emission on 2 ks and day timescales, as well as in the total data set.

  18. Neutron Resonance Parameters of 238U and the Calculated Cross Sections from the Reich-Moore Analysis of Experimental Data in the Neutron Energy Range from 0 keV to 20 keV

    Derrien, H

    2005-12-05

    The neutron resonance parameters of {sup 238}U were obtained from a SAMMY analysis of high-resolution neutron transmission measurements and high-resolution capture cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) in the years 1970-1990, and from more recent transmission and capture cross section measurements performed at the Geel Linear Accelerator (GELINA). Compared with previous evaluations, the energy range for this resonance analysis was extended from 10 to 20 keV, taking advantage of the high resolution of the most recent ORELA transmission measurements. The experimental database and the method of analysis are described in this report. The neutron transmissions and the capture cross sections calculated with the resonance parameters are compared with the experimental data. A description is given of the statistical properties of the resonance parameters and of the recommended values of the average parameters. The new evaluation results in a slight decrease of the effective capture resonance integral and improves the prediction of integral thermal benchmarks by 70 pcm to 200 pcm.

  19. First INTEGRAL observations of V404 Cygni during the 2015 outburst : spectral behavior in the 20 - 650 keV energy range

    Roques, Jean-Pierre; Bazzano, Angela; Fiocchi, Mariateresa; Natalucci, Lorenzo; Ubertini, Pietro

    2015-01-01

    In June 2015, the source V404 Cygni (= GS2023+38) underwent an extraordinary outburst. We present the results obtained during the first revolution dedicated to this target by the INTEGRAL mission, and focus on the spectral behavior in the hard X-ray domain, using both SPI and IBIS instruments. The source exhibits extreme variability, and reaches fluxes of several tens of Crab. However, the emission between 20 and 650 keV can be understood in terms of two main components, varying on all the observable timescales, similar to what is observed in the persistent black hole system Cyg X-1. The low energy component (up to ~ 200 keV) presents a rather unusual shape, probably due to the intrinsic source variability. Nonetheless, a satisfactory description is obtained with a Comptonization model, if an unusually hot population of seed photons ($kT_0$ ~ 7 keV) is introduced. Above this first component, a clear excess extending up to 400-600 keV leads us to investigate a scenario where an additional (cutoff) power law co...

  20. Plasma X-ray emission in the 20-500 keV range during lower hybrid current drive on Alcator

    An array of eight 1'' x 3'' NaI scintillators has been used to collect plasma hard x-ray spectra (E/sub γ/>20 keV) emitted perpendicular to the magnetic axis during lower hybrid current drive on Alcator. The spectra exhibit a tail extending out to at least 300 keV and the profiles are generally peaked. These results show that the slope of the x-ray spectra increases with increasing plasma radius. Equivalently, the emission profiles tend to broaden with increasing photon energy. Also, the x-ray spectra slope increases at each radial location as the relative phasing of adjacent waveguides in the grill antenna is decreased. Preliminary results also suggest that the x-ray spectra tend to flatten and that the emission profiles tend to peak up with decreasing plasma density or increasing magnetic field. In addition, the initial results of an array for measuring the high energy x-ray emission from Alcator as a function of the emission angle relative to the magnetic axis are presented

  1. 2-20 ns interframe time 2-frame 6.151 keV x-ray imaging on the recently upgraded Z Accelerator: a progress report.

    Bennett, G R; Smith, I C; Shores, J E; Sinars, D B; Robertson, G; Atherton, B W; Jones, M C; Porter, J L

    2008-10-01

    When used for the production of an x-ray imaging backlighter source on Sandia National Laboratories' recently upgraded 26 MA Z Accelerator, the terawatt-class, multikilojoule, 526.57 nm Z-Beamlet laser (ZBL) [P. K. Rambo et al., Appl. Opt. 44, 2421 (2005)], in conjunction with the 6.151 keV (1s(2)-1s2p triplet line of He-like Mn) curved-crystal imager [D. B. Sinars et al., Rev. Sci. Instrum. 75, 3672 (2004); G. R. Bennett et al., Rev. Sci. Instrum. 77, 10E322 (2006)], is capable of providing a high quality x radiograph per Z shot for inertial confinement fusion (ICF), complex hydrodynamics, and other high-energy-density physics experiments. For example, this diagnostic has recently afforded microgram-scale mass perturbation measurements on an imploding ignition-scale 1 mg ICF capsule [G. R. Bennett et al., Phys. Rev. Lett. 99, 205003 (2007)], where the perturbation was initiated by a surrogate deuterium-tritium (DT) fuel fill tube. Using an angle-time multiplexing technique, ZBL now has the capability to provide two spatially and temporally separated foci in the Z chamber, allowing "two-frame" imaging to be performed, with an interframe time range of 2-20 ns. This multiplexing technique allows the full area of the four-pass amplifiers to be used for the two pulses, rather than split the amplifiers effectively into two rectangular sections, with one leg delayed with respect to the other, which would otherwise double the power imposed onto the various optics thereby halving the damage threshold, for the same irradiance on target. The 6.151 keV two frame technique has recently been used to image imploding wire arrays, using a 7.3 ns interframe time. The diagnostic will soon be converted to operate with p-rather than s-polarized laser light for enhanced laser absorption in the Mn foil, plus other changes (e.g., operation at the possibly brighter 6.181 keV Mn 1s(2)-1s2p singlet line), to increase x-ray yields. Also, a highly sensitive inline multiframe ultrafast (1 ns

  2. The emission of Cygnus X-1: observations with INTEGRAL SPI from 20 keV to 2 MeV

    Jourdain, Elisabeth; Malzac, Julien

    2011-01-01

    We report on Cyg X-1 observations performed by the SPI telescope onboard the INTEGRAL mission and distributed over more than 6 years. We investigate the variability of the intensity and spectral shape of this peculiar source in the hard X-rays domain, and more particularly up to the MeV region. We first study the total averaged spectrum which presents the best signal to noise ratio (4 Ms of data). Then, we refine our results by building mean spectra by periods and gathering those of similar hardness. Several spectral shapes are observed with important changes in the curvature between 20 and 200 keV, even at the same luminosity level. In all cases, the emission decreases sharply above 700 keV, with flux values above 1 MeV (or upper limits) well below the recently reported polarised flux (Laurent et al. 2011), while compatible with the MeV emission detected some years ago by CGRO/COMPTEL (McConnell et al., 2002). Finally, we take advantage of the spectroscopic capability of the instrument to seek for spectral f...

  3. Ranges, Reflection and Secondary Electron Emission for keV Hydrogen Ions Incident on Solid N2

    Børgesen, P.; Sørensen, H.; Hao-Ming, Chen

    1983-01-01

    Ranges were measured for 0.67–3.3 keV/amu hydrogen and deuterium ions in solid N2. Comparisons with similar results for N2-gas confirm the previously observed large phase effect in the stopping cross section. Measurements of the secondary electron emission coefficient for bulk solid N2 bombarded by...... 0.67–9 keV/amu ions also seem to support such a phase effect. It is argued that we may also extract information about the charge state of reflected projectiles....

  4. Reduction in the intensity of solar X-ray emission in the 2- to 15-keV photon energy range and heating of the solar corona

    Mirzoeva, I. K., E-mail: colombo2006@mail.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2013-04-15

    The time profiles of the energy spectra of low-intensity flares and the structure of the thermal background of the soft X-ray component of solar corona emission over the period of January-February, 2003, are investigated using the data of the RHESSI project. A reduction in the intensity of X-ray emission of the solar flares and the corona thermal background in the 2- to 15-keV photon energy range is revealed. The RHESSI data are compared with the data from the Interball-Geotail project. A new mechanism of solar corona heating is proposed on the basis of the results obtained.

  5. Investigation of Methanol Formation Mechanisms in H2O+CH4 Ices Subjected to 5 keV Electrons at a 10-100 K Temperature Range

    Stelmach, K. B.; Cooper, P. D.

    2014-12-01

    Methane (CH4) and water are one of the most common molecules in both planetary bodies and interstellar dust grains. Another common molecule, methanol (CH3OH), is thought to form in CH4+H2O ices. However, the exact formation mechanisms of methanol from cosmic rays are not well known, especially in the temperatures of interest. Experiments were performed using high energy electrons (5 keV) to irradiate mixtures of 1:10, 1:5, and 1:3 CH4+H2O ices under a temperature range of 10-100 Kelvin with Fourier Transform Infrared (FTIR) spectroscopy being used to identify the products. Isotopologues of the two molecules (D2O and CD4) were used to probe for the mechanisms. Other products were formed as well and their potential mechanisms are identified. The implications of the mechanisms for planetary and interstellar chemistry are discussed.

  6. Studies of Transport Properties and Critical Temperature Suppression Mechanism in Yttrium BARIUM(2) COPPER(3) Oxygen(x) Thin Films Irradiated with 20 TO 120 KEV Electrons

    Lin, Jiunn-Yuan

    1995-11-01

    We present comprehensive studies of the effects of 20 to 120 keV electron irradiation on rm YBa_2Cu_3O_{x} thin films. Above 60 keV, T_{c } of irradiated samples is suppressed accompanied by a significant increase in residual resistivity, while the carrier concentration remains relatively unchanged. The plane oxygen defects produced by irradiation are found to be responsible for T_{c} suppression. The II suppression mechanism is discussed within several theoretical frameworks. Though in qualitative agreement with d-wave pairing symmetry, our results show a T_{c} suppression rate three times as slow as predicted by the theory when resistivity data are used to extract the impurity scattering rate. Alternatively, phase fluctuations theory gives a qualitative description as well. The displacement energy of plane oxygen is found to be 8.3 eV, which corresponds to a threshold electron energy 58 keV. Finally, an empirical relation is proposed to describe the temperature dependence of the Hall coefficient.

  7. The Hard X-ray 20-40 keV AGN Luminosity Function

    Beckmann, V; Shrader, C R; Gehrels, N; Produit, N

    2006-01-01

    We have compiled a complete extragalactic sample based on 25,000 deg^2 to a limiting flux of 3E-11 ergs/cm**2/sec (7,000 deg^2 to a flux limit of 1E-11 ergs/cm**2/sec) in the 20 - 40 keV band with INTEGRAL. We have constructed a detailed exposure map to compensate for effects of non-uniform exposure. The flux-number relation is best described by a power-law with a slope of alpha = 1.66+-0.11. The integration of the cumulative flux per unit area leads to f = 2.6E-10 ergs/cm**2/sec/sr, which is about 1% of the known 20 - 40 keV X-ray background. We present the first luminosity function of AGNs in the 20-40 keV energy range, based on 38 extragalactic objects detected by the imager IBIS/ISGRI on-board INTEGRAL. The luminosity function shows a smoothly connected two power-law form, with an index of gamma_1 = 0.8 below, and gamma_2 = 2.1 above the turn-over luminosity of L* = 2.4E43 ergs/sec. The emissivity of all INTEGRAL AGNs per unit volume is W(> 1E41 ergs/sec) = 2.8E38 ergs/sec/Mpc**3. These results are consis...

  8. The Range of 1-3 keV Electrons in Solid Oxygen and Carbon Monoxide

    Oehlenschlæger, M.; Andersen, H.H.; Schou, Jørgen; Sørensen, H.

    The range of 1-3 keV electrons in films of solid oxygen and carbon monoxide has been measured by a mirror substrate method. The technique used here is identical to the one previously used for range measurements in solid hydrogen and nitrogen. The range in oxygen is slightly shorter than that in...... nitrogen whereas the range in carbon monoxide is about 20% larger than that in the nitrogen....

  9. The range of 1-3 keV electrons in solid oxygen and carbon monoxide

    The range of 1-3 keV electrons in films of solid oxygen and carbon monoxide has been measured by a mirror-substrate method. The technique used here is identical to the one previously used for range measurements on solid hydrogen and nitrogen. The range in oxygen is slightly shorter than that in nitrogen whereas the range in carbon monoxide is about 20% larger than that in the nitrogen. (orig.)

  10. The Range of 1-3 keV Electrons in Solid Oxygen and Carbon Monoxide

    Oehlenschlæger, M.; Andersen, H.H.; Schou, Jørgen;

    1985-01-01

    The range of 1-3 keV electrons in films of solid oxygen and carbon monoxide has been measured by a mirror substrate method. The technique used here is identical to the one previously used for range measurements in solid hydrogen and nitrogen. The range in oxygen is slightly shorter than that in...... nitrogen whereas the range in carbon monoxide is about 20% larger than that in the nitrogen....

  11. Attosecond quantum entanglement in neutron Compton scattering from water in the keV range

    Scattering of neutrons in the 24-150keV incident energy range from H2O relative to that of D2O and H2O-D2O mixtures was reported very recently. Studying time-of-flight integrated intensities, the applied experimental procedure appears to be transparent and may open up a novel class of neutron experiments regarding the 'anomalous' scattering from protons, firstly observed in our experiment at ISIS in the 5-100eV range. The keV-results were analyzed within standard theory, also including (1) multiple scattering and (2) the strong incident-energy dependence of the neutron-proton cross-section σH(E0) in this energy range. The analysis reveals a striking anomalous ratio of scattering intensity of H2O relative to that of D2O of about 20%, thus being in surprisingly good agreement with the earlier results of the original experiment at ISIS

  12. R-matrix analysis of 235U neutron transmission and cross sections in the energy range 0 to 2.25 keV

    This document describes a new R-matrix analysis of 235U cross section data in the energy range from 0 to 2,250 eV. The analysis was performed with the computer code SAMMY, that has recently been updated to permit, for the first time, inclusion of both differential and integral data within the analysis process. Fourteen differential data sets and six integral quantities were used in this evaluation: two measurements of fission plus capture, one of fission plus absorption, six of fission alone, two of transmission, and one of eta, plus standard values of thermal cross sections for fission, capture, and scattering, and of K1 and the Westcott g-factors for both fission and absorption. An excellent representation was obtained for the high-resolution transmission, fission, and capture cross-section data as well as for the integral quantities. The result is a single set of resonance parameters spanning the entire range up to 2,250 eV, a decided improvement over the present ENDF/VI evaluation, in which eleven discrete resonance parameter sets are required to cover that same energy range. This new evaluation is expected to greatly improve predictability of the criticality safety margins for nuclear systems in which 235U is present

  13. R-matrix analysis of {sup 235}U neutron transmission and cross sections in the energy range 0 to 2.25 keV

    Leal, L.C.; Derrien, H.; Larson, N.M.; Wright, R.Q.

    1997-11-01

    This document describes a new R-matrix analysis of {sup 235}U cross section data in the energy range from 0 to 2,250 eV. The analysis was performed with the computer code SAMMY, that has recently been updated to permit, for the first time, inclusion of both differential and integral data within the analysis process. Fourteen differential data sets and six integral quantities were used in this evaluation: two measurements of fission plus capture, one of fission plus absorption, six of fission alone, two of transmission, and one of eta, plus standard values of thermal cross sections for fission, capture, and scattering, and of K1 and the Westcott g-factors for both fission and absorption. An excellent representation was obtained for the high-resolution transmission, fission, and capture cross-section data as well as for the integral quantities. The result is a single set of resonance parameters spanning the entire range up to 2,250 eV, a decided improvement over the present ENDF/VI evaluation, in which eleven discrete resonance parameter sets are required to cover that same energy range. This new evaluation is expected to greatly improve predictability of the criticality safety margins for nuclear systems in which {sup 235}U is present.

  14. 2-dimensional primary x-ray image formation and quality in angiography using absorption-edge filters in the range 40-60 keV

    Computer simulation techniques are used to examined Pr, Gd and Yb (K-edge) filters for the x-ray imaging of iodinated blood vessels. The performance of these filters is compared to a standard 2 mm Al filter with respect to vessel contrast, patient exposure and integral absorbed dose and x-ray tube loading. Additional simulations investigate how 0.2 mm Pr, Gd or Yb filters interact with the non-isotropic x-ray spectrum and affect (1) the background intensity and vessel contrast across the detector surface, and (2) the uniformity of exposure and integral absorbed dose across the patient. The results show that the uniformity of the primary x-ray image is neither degraded nor improved by these filters; however, patient exposure and dose can be substantially reduced and rendered more uniform

  15. Differential cross sections for γγ->panti p in the C.M. energy range from 2.0 to 3.1 GeV

    Exclusive production of proton-antiproton pairs by two photon scattering at c.m. energies between 2.0 GeV and 3.1 GeV has been measured with the TASSO detector at the e+e- storage ring PETRA. The angular distribution is flat within the accepted c.m. angular range vertical strokecosTHETAsup(*)vertical strokeγγ)xB(etasub(c)->panti p)<0.32 keV (95% c.l.) is found. (orig.)

  16. Photon interaction measurements of certain compounds in the energy range 30-660 keV

    The total photon interaction cross sections at six energies in the energy range 30-660 keV are determined in ten compounds, (NaNO3, KNO3, Sr(NO3)2, NaCl, SrCl2-2H2), NaClO3, (NH4)SO4, MgSO4) using a NaI(Tl) scintillation spectrometer in a good geometry setup. Analysis of the experimental data in terms of cross sections and effective atomic numbers is presented

  17. Electron capture by 20-150 keV protons on hydrocarbon gases

    Cross sections are reported for electron capture by 20-150 keV protons incident on CO, CH4, C2H6, and C3H8 target gases. These cross sections were obtained from a new system which measures the proton flux prior to entering and immediately after leaving a differentially pumped gas cell. The absolute magnitude and energy dependence of the values obtained from this apparatus compare favorably with existing measurements where such values are available, the C3H8 values are new to the literature. Attempts to reconcile the hydrocarbon data in terms of generalized additive rules have met with limited success below 70 keV but fail as the projectile velocity increases. (orig.)

  18. MEDIUM-RANGE ORDER CLUSTERS IN Fe-2.0%C ALLOY MELT

    X.B. Qin; S.J. Cheng; X.F. Bian

    2003-01-01

    The structure of Fe-2.0%C alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an X-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, the coordination numbers, the correlation radius and the atom density increased, whereas the pre-peak of the structure factors curve remained almost at the same position. The appearance of the pre-peak indicated that the liquid structure and the solid structure of the Fe-2.0%C alloy were correlated.

  19. Biological effect of 20 keV N+ ion implantation on Stevia rebaudianum

    The germinability and gemination rate of Stevia rebaudianum seeds implanted with 20 keV N+ ions in doses of 0 (CK), 100 x 2500, 400 x 2500 and 1000 x 2500 N+/cm2 were studied by analyzing the differences in seed germinability and gemination rate between the groups. By statistical analysis, the germinability and gemination rate were affected at the level of α=0.05 by the implantation dose. The results showed that the germinability and gemination rate increased with the dose first and then decreased. At 400 x 2500 N+/cm2, the seeds had the largest germinability and the gemination rate. (authors)

  20. Inelastic processes in K^(+)- He collisions in energy range 0.7 - 10 keV

    Lomsadze, R A; Kezerashvili, R Ya; Mosulishvili, N O; Phaneuf, R

    2013-01-01

    Absolute cross sections for charge exchange, ionization, stripping and excitation in K^(+) - He collisions were measured in the ion energy range 0.7 - 10 keV. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The increase of the excitation probability of inelastic channels with the angle of scattering is revealed. An exceptionally highly excited state of He is observed and a peculiarity for the excitation function of the resonance line is explained. The intensity ratio for the excitation of the K II \\lambda = 60.1 nm and \\lambda = 61.2 nm lines is 5:1 which indicates the high probability for excitation of the singlet resonance level $^{1}$P$_{1}$ compared to the triplet level $^{3}$P$_{1}$. The similarity of the population of the 4p state of the potassium ion and atom as well as the anomalously small values of the excitation cross sections are explained.

  1. Structural changes of surfaces of spacecraft solar array protective glasses being irradiated by 20-keV electrons

    Khasanshin, R. H.; Novikov, L. S.

    2016-05-01

    When irradiating K-208 and CMG glasses by 20-keV electrons with flux densities of 1010 < φe < 2 × 1011 cm-2 s-1 in vacuum 10-4 Pa, electrostatic discharges accompanied by plasma emission and destruction of glass surfaces were observed. Examination of glasses by atomic force microscopy (AFM) showed significant difference in structural changes of surfaces of K-208 and CMG samples irradiated by equal flux densities within the range from 2.0 × 1010 to 9.0 × 1010 cm-2 s-1 that can be explained by different mechanisms of removal of charge accumulated in glasses. Surface discharges generating channels on surfaces of K-208 and CMG glasses appear when φ ⩾ 7.4 × 1010 cm-2 s-1 and φ ⩾ 8.7 × 1010 cm-2 s-1 respectively. In average, if radiation conditions are the same and φ ⩾ 1.4 × 1011 cm-2 s-1, the channels are 1.5 times deeper in K-208 than in CMG.

  2. Measurement 20-200 keV hard X-ray based on CdTe detector in EAST Tokamak

    Background: Accurate and quantitative measurement of plasma radiation is a key issue to Tokamak, toroidal magnetic confinement device. The radiations from Tokamak cover large energy range. Driven by the determination of the obtaining of hard X-ray spectra, a new system based on a high performance CdTe detector was built up in EAST Tokamak, the first non-circle cross-section in the world. Purpose: Introduces the device of hard X-ray diagnosis system in the EAST Tokamak on the Port A. The system can measure the plasma hard X-ray (20-200 keV) spectra under different discharge conditions, including Ohmical shot and Lower Hybrid Current Drive (LHCD) shot. The research of high speed electron which produced by LHCD is also the aim of the new system. Methods: A high performance CdTe detector was using in EAST Tokamak to measure the hard X-ray (20-200 keV) spectra. Results: The results show that the new system based on a high performance CdTe can meet the requirements for measuring the EAST Tokamak. Conclusions: A preliminary experimental result showed that the system can meet the requirements for measuring the X-ray bremsstrahlung of plasma in the energy range from 20 to 200 keV Calibration result and typical measurement result on EAST are present in this paper. (authors)

  3. Study of pp interactions in the momentum range 0.9 to 2.0 GeV/c

    Shimizu, F.; Koiso, H.; Kubota, Y.; Sai, F.; Sakamoto, S.; Yamamoto, S. S.

    1982-11-01

    pp interactions at 11 momenta in the range 0.9 to 2.0 GeV/ c have been studied. The elastic angular distributions, covering the c.m. angular range 22°-90°, agree in general with Hoshizaki's phase-shift analysis which shows the looping 1D in and 3F 3 amplitudes in the Argand diagram. About 80% of pn π+ events come from the n Δ++ state at all momenta above 1.2 GeV/ c. The behavior of the density matrix elements of the Δ++ show no momentum or angular dependence. A large fraction of pp π0 events also come from the p Δ+ state at all momenta above 1.2 GeV/ c. The behavior of the Δ+ density matrix elements is similar to that for the case of Δ++.

  4. Measurement of Fission Cross-Sections for Neutrons of Energies in the Range 40-500 keV

    Measurements have been made of the fission cross-section of U233, U234 , U236, Np237, Pu239 and Pu241 at several neutron energies between 40 keV and 500 keV. Measurements in this energy range are of importance in reactor calculations especially in fast dilute systems where the neutron flux is high in the 10- 100-keV energy range. Recent measurements at this laboratory of the U235 fission cross-section gave absolute values slightly lower than previous data. The present series of measurements are made relative to the new values of the U235 fission cross-section using back-to-back ionization chambers. The fissile foils were assayed by α-assay, direct weighing and coulometry. Good agreement was obtained between these assays. The fission measurements have an estimated accuracy of between 1 % and.2% and,combined with the, error on the U235 fission cross-section,give a final error of about 3% in the fission cross-sections. The present results together with those of previous measurements are given, and the corrections for fission- fragment absorption, backgrounds and scattering are discussed. (author)

  5. 12.2-GHz methanol maser MMB follow-up catalogue - IV. Longitude range 20° to 60°

    Breen, S. L.; Ellingsen, S. P.; Caswell, J. L.; Green, J. A.; Voronkov, M. A.; Avison, A.; Fuller, G. A.; Quinn, L. J.

    2016-04-01

    This is the fourth and final instalment of a series of catalogues presenting 12.2-GHz methanol maser observations made towards each of the 6.7-GHz methanol masers detected in the Methanol Multibeam (MMB) Survey. This final portion of the survey covers the 20° to 60° longitude range, increasing the 12.2-GHz follow-up range to the full MMB coverage of 186° ≥ l ≤ 60° and |b| ≤ 2°. Towards a total of 260 6.7-GHz MMB methanol masers (we were unable to observe five of the MMB sources in this longitude range) we detect 116 12.2-GHz masers counterparts, 64 of which were discovered in this survey. Including data from the literature, we find that there are 12.2-GHz methanol masers towards 47.1 per cent of the 6.7-GHz methanol masers in this portion of the Galaxy. Across the entire MMB survey range we find a detection rate of 45.3 per cent. We find that the detection rate of 12.2-GHz methanol masers as a function of Galactic longitude is not uniform and that there is an excess of masers with broad velocity ranges at longitudes near 30° and 330°. Comparing the occurrence of 12.2-GHz methanol masers with MMB-targeted CO observations has shown that those outflows associated with a 12.2-GHz source have a larger average dynamical timescale than those associated with only 6.7-GHz methanol masers, supporting the notion that the 12.2-GHz masers are associated with a later phase of high-mass star formation.

  6. Re-measurement of the neutron-induced gamma-ray production cross sections for iron in the energy range 850 keV less than or equal to E/sub n/ less than or equal to 20. 0 MeV. [Tables

    Chapman, G.T.; Morgan, G.L.; Perey, F.G.

    1976-07-01

    Values of the gamma-ray production cross sections for neutron interactions with iron as reported by previous investigators have differed by as much as a factor of 1.5 or more at neutron energies greater than about 5 MeV. Because of this discrepancy, the measurements were repeated at ORNL using the ORELA as a pulsed source of neutrons with energies between 850 keV and 20 MeV. The data were obtained using a NaI(Tl) gamma-ray spectrometer oriented at an angle of 125/sup 0/ to the incident neutron beam. The sample was positioned in the beam at a distance of 47.35 meters from the neutron source. The resulting data, presented as differential cross sections (d/sup 2/sigma/d..cap omega..dE) for gamma rays between 0.7 and 10.5 MeV, show good agreement with some previously published data, but are significantly different from previous ORNL measurements for neutron energies greater than 5 MeV.

  7. Measurement of neutron capture cross section of 75As in the energy range from 29 to 1100 keV

    The cross sections for the 75As(n,γ)76As reaction were measured relatively to that of 197Au in neutron energy range from 29 to 1100 keV, using the activation technique. Neutrons were produced via the 7Li(p,n)7Be and T(p,n)3He reactions with a 2.5 MV Van de Graaff accelerator at Sichuan University. The activities after irradiation were measured with a calibrated high resolution HPGe detector. The errors of the measurements are 6.7%-7.8%. The experiment results were compared with existing data

  8. A Selective Neutron Detector in the keV Region Utilizing the 19F (n, γ 20F Reaction

    The Research Swimming-Pool Reactor R2-0 at Studsvik has been used to investigate some resonance and threshold reactions for neutron flux measurements. This reactor, equipped with MTR type fuel elements, has a maximum neutron flux of about 1012 n/cm2/sec, giving a thermal output of 100 kW. A pneumatic rabbit was constructed to bring the samples in activation position, in which there was 15 cm H2O and 1.2 cm Al between reactor and foil. A covering, containing 1.22 g 10B/cm2 was pushed over the cadmium-covered Al tube of the rabbit. The activation of the foil was measured with a Nal(Tl)-scintillation spectrometer. From the gamma ray spectrum, recorded on a 256 channel pulse height analyzer, the epithermal neutron flux per unit of In E interval was calculated. The activation cross section for 19F (n, γ) 20F in the 10B-covering was computed to be 16 mb, and about 60 % of the induced activity is due to neutrons in the energy range of 20-70 keV. The experimental results were compared with those obtained from the more known resonance reactions 63Cu (n, γ) 64Cu and 27Al (n, γ) 28Al. The epithermal neutron flux experiments are in good agreement with each other. The fast neutron flux measurements were carried out with the following threshold detectors: 197Au (n, n') 197mAu, 58Ni (n, p) 58Co, 27Al (n, p) 27Mg and 19F (n, p) 19O. From these experiments the ratio of φepi/φfiss =0.045 ± 0.010 is determined at the activation position. The half-life of 197Au m was determined to 7.35 ± 0.25 sec

  9. PET surface modification by 0.2 keV and 2.5 keV argon ions

    PET foils have a high potential as a material for biomedical and electrical industries. PET foils were irradiated by ions for variable irradiation time. The effects of low (2.5, 0.2 keV) energy argon ion flux irradiation on the surfaces of polyethylene terephthalate thin foils (PET) were studied. The source of ions was an ECR Ion Gun with settable acceleration voltages. The modified foils were investigated by in-situ X-ray Photoelectron Spectroscopy (XPS) and ex-situ Fourier transform infrared spectroscopy (FTIR). The significant changes in the chemical composition of the surface layer were quantitatively studied by XPS. The scission of the chains in the surface layer of PET foil was induced by ion flux interaction with PET surface. The strong selective sputtering of oxygen atoms in PET film was observed. The atomic ratio O/C was decreased by 0.2keV and 2.5keV argon ion flux from 0.40 to 0.25 and 0.04 respectively. The oxygen atoms in ester bonds are detached first. This phenomenon is responsible for the creation of carbon-rich surface layer. The FTIR analyses identified changes in chemical composition but with no obvious correlation to surface changes. PET volume changes in the spectra were probably results of photons from the ion source influence on PET foils.

  10. Study of avalanche photodiodes for soft X-ray detection below 20keV

    The performance of the large area reach-through avalanche photodiode (APD), manufactured by Hamamatsu Photonics, K.K. as a high resolution X-ray detector is presented. The mentioned APD has an area of 3mm, a fast time response for signal carrier collection and its thick depletion layer of 130μm shows a potential to be used as an effective X-ray absorber below 20keV. Having a capacitance of ∼10pF and a low dark current of 5nA for a gain of 15, at room temperature, this APD had demonstrated one of the best energy resolutions within this kind of devices: 6.4% (FWHM) for 5.9keV photons with a minimum detectable energy of 0.3keV, measured at -20 deg. C. The experiments for the timing property were made in a synchrotron beam facility using an 8keV X-ray beam; the reached count rate was above 108 counts/s, corresponding to a very short dead time of 4.5ns/pulse. In order to test the radiation hardness of the APD, the device was irradiated at a Ring Cyclotron Facility with a 53.5MeV proton beam. The total dose was of 11.3krad and no fatal damage was found in the APD, although the dark current of the APD had shown an increase of one order of magnitude. Finally, the obtained results allow us to affirm that the reach-through APD has the potential to become an excellent X-ray detector, especially in the space mission application

  11. Study of avalanche photodiodes for soft X-ray detection below 20 keV

    Yatsu, Y.; Kuramoto, Y.; Kataoka, J.; Kotoku, J.; Saito, T.; Ikagawa, T.; Sato, R.; Kawai, N.; Kishimoto, S.; Mori, K.; Kamae, T.; Ishikawa, Y.; Kawabata, N.

    2006-08-01

    The performance of the large area reach-through avalanche photodiode (APD), manufactured by Hamamatsu Photonics, K.K. as a high resolution X-ray detector is presented. The mentioned APD has an area of 3 mm ∅, a fast time response for signal carrier collection and its thick depletion layer of 130 μm shows a potential to be used as an effective X-ray absorber below 20 keV. Having a capacitance of ˜10 pF and a low dark current of 5 nA for a gain of 15, at room temperature, this APD had demonstrated one of the best energy resolutions within this kind of devices: 6.4% (FWHM) for 5.9 keV photons with a minimum detectable energy of 0.3 keV, measured at -20C. The experiments for the timing property were made in a synchrotron beam facility using an 8 keV X-ray beam; the reached count rate was above 108 counts/s, corresponding to a very short dead time of 4.5 ns/pulse. In order to test the radiation hardness of the APD, the device was irradiated at a Ring Cyclotron Facility with a 53.5 MeV proton beam. The total dose was of 11.3 krad and no fatal damage was found in the APD, although the dark current of the APD had shown an increase of one order of magnitude. Finally, the obtained results allow us to affirm that the reach-through APD has the potential to become an excellent X-ray detector, especially in the space mission application.

  12. Experimental determination of sensitivity of DN-A-1 dosimeter and 6LiJ(Eu) scintillation detector in sphere polyethylene moderators in the 30 keV neutron energy range

    DH-A-1 dosimeter and 6LiJ(Eu) detector, located in the center of polyethylene spheres with various diameters, were calibrated by means of neutrons with the energy of about 30 keV. The data on the detectors responses enable one to determine the shape of responses as a function of neutron energy more definitely at the energy range from some keV to some tens of keV. For DN-A-1 dosimeter response at neutrons and at neutrons in the energy range of about 30 keV the agreement is better than the uncertainties of measurements (about 20%)

  13. Charge-transfer cross sections of ground state He+ ions in collisions with He atoms and simple molecules in the energy range below 4.0 keV

    Charge-transfer cross sections of the ground state He+ ions in collisions with He atoms and simple molecules (H2, D2, N2, CO and CO2) have been measured in the energy range of 0.20 to 4.0 keV with the initial growth rate method. Since previously published experimental data are scattered in the low energy region, the present observations would provide reasonably reliable cross section data below 4 keV. The charge transfer accompanied by dissociation of product molecular ion can be dominant at low energies for molecular targets. In He+ + D2 collisions, any isotope effect was not observed over the present energy range, compared to H2 molecule. (author)

  14. Injection and diffusive transport of suprathermal through energetic solar flare protons (35 keV to 20 MeV)

    Beeck, J.; Mason, G. M.; Hamilton, D. C.; Marsden, R. G.; Sanderson, T. R.

    1990-01-01

    Consideration is given to the injection and interplanetary propagation of low-energy protons caused by the solar particle event of July 20, 1981, in which flare protons in the range from 35 keV to 20 MeV were observed by instruments on ISEE 3. The observed time-intensity and time-anisotropy profiles were fitted over the entire energy range using a model based on the spherically symmetric Fokker-Plank equation, including convection, diffusion, and adiabatic deceleration. The results are used to discuss the behavior of the radial interplanetary diffusion coefficient and the scattering mean free path for protons. Also, evidence is found for diffusive coronal shock acceleration of protons during the event.

  15. L-shell ionization of Sn and Gd by 20 - 100 keV electron impact

    Measurements have been made of the relative x-ray production cross section Lsub(α)/Lsub(γ), Lsub(α)/Lsub(β) and Lsub(α)/Lsub(l) using electrons of energy 20 to 100 keV incident on thin targets of tin and gadolinium. The experimental ratios obtained have been compared with theoretical values. Modification of these ratios due to the formation of double vacancy atomic states has been calculated, but this effect on its own is not sufficient to account for the discrepancy between theory and experimental results

  16. Microchannel plate pinhole camera for 20 to 100 keV x-ray imaging

    We present the design and construction of a sensitive pinhole camera for imaging suprathermal x-rays. Our device is a pinhole camera consisting of four filtered pinholes and microchannel plate electron multiplier for x-ray detection and signal amplification. We report successful imaging of 20, 45, 70, and 100 keV x-ray emissions from the fusion targets at our Novette laser facility. Such imaging reveals features of the transport of hot electrons and provides views deep inside the target

  17. First direct high-precision energy determination for the 8.4 and 20.7 keV nuclear transitions in {sup 169}Tm

    Inoyatov, A.Kh. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); National University, Institute of Applied Physics, Tashkent (Uzbekistan); Kovalik, A. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, Rez near Prague (Czech Republic); Filosofov, D.V.; Perevoshchikov, L.L. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Rysavy, M. [Nuclear Physics Institute of the ASCR, Rez near Prague (Czech Republic); Gurov, Yu.B. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation)

    2015-06-15

    Energies of 8410.1 ± 0.4, 20743.9 ± 0.3, and 63121.6 ± 1.2 eV were determined for the 8.4 keV M1 + E2, 20.7 keV M1 + E2, and 63.1 keV E1 nuclear transitions in {sup 169}Tm (generated in the EC decay of {sup 169}Yb), respectively, by means of the internal conversion electron spectroscopy. The {sup 169}Yb sources used were prepared by vacuum evaporation deposition on polycrystalline carbon and platinum foils as well as by ion implantation at 30keV into a polycrystalline aluminum foil. The relevant conversion electron spectra were measured by a high-resolution combined electrostatic electron spectrometer at 7 eV instrumental resoluition. Values of 0.0326(14) and 0.0259(17) were derived from our experimental data for the E2 admixture parameter δ (E2/M1) for the 8.4 and 20.7 keV transitions, respectively. A possible effect of nuclear structure on multipolarity of the 20.7 keV transition was also investigated. (orig.)

  18. Yield of chromosomal aberrations and recoil particle range in Chineses hamster fibroblasts exposed to 8.5 to 500 keV neutrons

    Induction of chromatid aberrations in S-phase Chinese hamster fibroblasts has been studied for irradiation by 60Co gamma rays and neutrons of average energy 8.5, 45, 83, 200 and 500 keV. At 10 per cent aberration level the relative biological afficiency varied between 2.2 +- 0.6 (at 8.5 keV) and a maximum of 47 +- 9 (at 200 keV). The neutron generated recoils have short range in comparison to chromosomal dimensions. The strong variation with neutron energy is therefore not necessarily reflecting variations in the average linear energy transfer. Good agreement between experimental and predicted response was obtained when effects ascribed to range were considered. A critical volume within which primary lesions should occur in order to make chromosomal aberrations probable was derived. The corresponding site radius was estimated to be 1-3 μm. (author)

  19. DNA strand breaks and crosslinks induced by transient anions in the range 2-20 eV

    Luo, Xinglan; Zheng, Yi, E-mail: Yizheng@fzu.edu.cn [Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002 (China); Sanche, Léon [Group in the Radiation Sciences, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4 (Canada)

    2014-04-21

    The energy dependence of the yields of single and double strand breaks (SSB and DSB) and crosslinks induced by electron impact on plasmid DNA films is measured in the 2-20 eV range. The yield functions exhibit two strong maxima, which are interpreted to result from the formation of core-excited resonances (i.e., transient anions) of the bases, and their decay into the autoionization channel, resulting in π → π{sup *} electronic transitions of the bases followed by electron transfer to the C–O σ{sup *} bond in the phosphate group. Occupancy of the σ{sup *} orbital ruptures the C–O bond of the backbone via dissociative electron attachment, producing a SSB. From a comparison of our results with those of other works, including theoretical calculations and electron-energy-loss spectra of the bases, the 4.6 eV peak in the SSB yield function is attributed to the resonance decay into the lowest electronically excited states of the bases; in particular, those resulting from the transitions 1{sup 3}A{sup ′} (π{sub 2} → π{sub 3}{sup *}) and 1{sup 3}A{sup ″} (n{sub 2} → π{sub 3}{sup *}) of thymine and 1{sup 3}A{sup ′} (π → π{sup *}) of cytosine. The strongest peak at 9.6 eV in the SSB yield function is also associated with electron captured by excited states of the bases, resulting mostly from a multitude of higher-energy π → π{sup *} transitions. The DSB yield function exhibits strong maxima at 6.1 and 9.6 eV. The peak at 9.6 eV is probably related to the same resonance manifold as that leading to SSB, but the other at 6.1 eV may be more restricted to decay into the electronic state 1{sup 3}A{sup ′} (π → π{sup *}) of cytosine via autoionization. The yield function of crosslinks is dominated by a broad peak extending over the 3.6-11.6 eV range with a sharper one at 17.6 eV. The different line shape of the latter function, compared to that of SSB and DSB, appears to be due to the formation of reactive radical sites in the initial supercoiled

  20. Formation of dot arrays with a pitch of 20 nm x 20 nm for patterned media using 30 keV EB drawing on thin calixarene resist

    Mohamad, Zulfakri bin [Department of Nano-Material System, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Shirai, Masumi [Department of Nano-Material System, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Sone, Hayato [Department of Production Science and Technology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Hosaka, Sumio [Department of Production Science and Technology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Kodera, Masatoshi [Department of Electronics, Information and Communication Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585 (Japan)

    2008-01-16

    We studied the possibility of achieving very fine-pitch dot arrays with a pitch of 20 nm x 20 nm using 30 keV electron beam (EB) drawing on negative calixarene resist. In order to form such patterns, we studied the dependence on resist thickness of the dot size and the packing. We propose EB drawing on an extremely thin film for very highly packed dot-array formation. Our experimental results demonstrate the possibility of forming highly packed dot-array patterns with a pitch of 20 nm x 20 nm and a resist thickness of about 13 nm, which corresponds to about 1.6 Tbits in{sup -2}.

  1. High-resolution integrated germanium Compton polarimeter for the γ-ray energy range 80 keV-1 MeV

    Sareen, R. A.; Urban, W.; Barnett, A. R.; Varley, B. J.

    1995-06-01

    Parameters which govern the choice of a detection system to measure the linear polarization of γ rays at low energies are discussed. An integrated polarimeter is described which is constructed from a single crystal of germanium. It is a compact planar device with the sectors defined electrically, and which gives an energy resolution in the add-back mode of 1 keV at 300 keV. Its performance is demonstrated in a series of calibration measurements using both unpolarized radiation from radioactive sources and polarized γ rays from the 168Er(α,2n)170Yb reaction at Eα=25 MeV. Polarization measurements at energies as low as 84 keV have been achieved, where the sensitivity was 0.32±0.09. The sensitivity, efficiency, and energy resolution are reported. Our results indicate that energy resolution should be included in the definition of the figure of merit and we relate the new definition to earlier work. The comparisons show the advantages of the present design in the energy range below 300 keV and its competitiveness up to 1500 keV.

  2. High-resolution integrated germanium Compton polarimeter for the γ-ray energy range 80 keV--1 MeV

    Parameters which govern the choice of a detection system to measure the linear polarization of γ rays at low energies are discussed. An integrated polarimeter is described which is constructed from a single crystal of germanium. It is a compact planar device with the sectors defined electrically, and which gives an energy resolution in the add-back mode of 1 keV at 300 keV. Its performance is demonstrated in a series of calibration measurements using both unpolarized radiation from radioactive sources and polarized γ rays from the 168Er(α,2n)170Yb reaction at Eα=25 MeV. Polarization measurements at energies as low as 84 keV have been achieved, where the sensitivity was 0.32±0.09. The sensitivity, efficiency, and energy resolution are reported. Our results indicate that energy resolution should be included in the definition of the figure of merit and we relate the new definition to earlier work. The comparisons show the advantages of the present design in the energy range below 300 keV and its competitiveness up to 1500 keV. copyright 1995 American Institute of Physics

  3. Energy dependence of some neutron dosimeter sensitivities in the 1 ev up to 4 kev energy range

    The sensitivities of DN-A-1 device and SNM-14 slow neutron counter with a combined moderator in the 1 eV up to 4 keV energy range has been experimentally determined. The IBR-30 reactor served as a neutron source, spectral distribution was performed by the time-of-flight method. The sensitivity constancy of a long counter in the 1 eV up to 4 keV energy range has been experimentally shown. The obtained sensitivity values and other data available could be used in determining energy dependencies of the device sensitivity in essential neutron energy range. It permits to evaluate their errors when using as dosimeters in radiation fields of nuclear physics installations

  4. Positron and electron backscattering from elemental solids in the 1-10 keV energy range

    Electron and positron backscattering coefficients are analytically calculated for a number of selected atomic targets in the energy range 1-10 keV and for incident angles between 0 deg. and 80 deg. The dependence of the backscattering coefficient on the material, on the projectile primary energy and on the incidence angle has been examined and discussed. Our results are found to be in better agreement with experiment than earlier Monte Carlo simulations

  5. Multispectrum processing approach of weak H sub 2 O profiles recorded with absorption paths ranging from 20 to 120 km

    Mandin, J Y; Jacquemart, D; Picqué, N; Guelachvili, G

    2003-01-01

    A new powerful approach to intracavity laser absorption spectroscopy is explored and evaluated. The laser emission is recorded with a high-resolution time-resolved step-scan Fourier transform interferometer. Time-resolved spectra are obtained from an intracavity laser set-up based on a vertical-cavity surface-emitting semiconductor laser located in the open air of the laboratory. A restricted set of H sub 2 sup 1 sup 6 O lines is used for the evaluation of the method. The lines are measured around 9625 cm sup - sup 1 in more than one hundred time-component spectra simultaneously recorded with absorption path lengths varying in arithmetic progression from 20 up to about 120 km. Data processing is performed with a multispectrum fitting program. The procedure is shown to be efficient for the quantitative determination of molecular parameters of ultra weak transitions.

  6. Simultaneous solution of Kompaneets equation and radiative transfer equation in the photon energy range 1-125 keV

    Radiative transfer equation in plane parallel geometry and Kompaneets equation is solved simultaneously to obtain theoretical spectrum of 1-125 keV photon energy range. Diffuse radiation field are calculated using time-independent radiative transfer equation in plane parallel geometry, which is developed using discrete space theory (DST) of radiative transfer in a homogeneous medium for different optical depths. We assumed free-free emission and absorption and emission due to electron gas to be operating in the medium. The three terms n, n2 and (∂n/∂xk) where n is photon phase density and xk=(hν/kTe), in Kompaneets equation and those due to free-free emission are utilized to calculate the change in the photon phase density in a hot electron gas. Two types of incident radiation are considered: (1) isotropic radiation with the modified black body radiation IMB and (2) anisotropic radiation which is angle dependent. The emergent radiation at τ=0 and reflected radiation τ=τmax are calculated by using the diffuse radiation from the medium. The emergent and reflected radiation contain the free-free emission and emission from the hot electron gas. Kompaneets equation gives the changes in photon phase densities in different types of media. Although the initial spectrum is angle dependent, the Kompaneets equation gives a spectrum which is angle independent after several Compton scattering times.

  7. Facilities and techniques for x-ray diagnostic calibration in the 100-eV to 100-keV energy range

    The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well

  8. Range Measurements of keV Hydrogen Ions in Solid Oxygen and Carbon Monoxide

    Schou, Jørgen; Sørensen, H.; Andersen, H.H.;

    1984-01-01

    Ranges of 1.3–3.5 keV/atom hydrogen and deuterium molecular ions have been measured by a thin-film reflection method. The technique, used here for range measurements in solid oxygen and carbon monoxide targets, is identical to the one used previously for range measurements in hydrogen and nitrogen....... The main aim was to look for phase-effects, i.e. gas-solid differences in the stopping processes. While measured ranges in solid oxygen were in agreement with known gas data, the ranges in solid carbon monoxide were up to 50% larger than those calculated from gas-stopping data. The latter result...

  9. Electron impact total cross sections for hydrogen molecule from 0.01 eV to 2 keV

    In the present work, we calculate electron impact total cross section for H2 molecule over wide range of incident energies starting from 0.01 eV to 2 keV. The present results are examined as function of incident energies and compared with available results.

  10. Range measurements of keV hydrogen ions in solid oxygen and carbon monoxide

    Ranges of 1.3-3.5 keV/atom hydrogen and deuterium molecular ions have been measured by a thin-film reflection method. The technique, used here for range measurements in solid oxygen and carbon monoxide targets, is identical to the one used previously for range measurements in hydrogen and nitrogen. The main aim was to look for phase-effects, i.e. gas-solid differences in the stopping processes. While measured ranges in solid oxygen were in agreement with known gas data, the ranges in solid carbon monoxide were up to 50% larger than those calculated from gas-stopping data. The latter result agrees with that previously found for solid nitrogen. (orig.)

  11. Effective atomic number of human enamel and dentin within a photo energy range from 10 to 200 KeV

    The Z and μ/p were determined regarding the total and partial photon interactions within the biological materials of human enamel and dentin, within the low photon energy range from 10 to 200 keV, which is of medical interest in terms of radiology. The mass attenuation coefficients were calculated by means of WinXCOM. The Z for total and partial photon interactions in the biological materials of human enamel and dentin have been determined within a radiological low photon energy range from 10 to 200 keV. The total Z values presented a similar behavior in both the enamel and dentin. The Z values decreased 23% in the enamel and by 32% in the dentin in direct proportion to the increase energy levels. The Z for all partial processes increased slightly and in direct proportion to the increase in energy levels. The value for photoelectric interaction proved to be the highest, whereas the value for incoherent scattering was the lowest. The total Z becomes a contribution due these three partial processes at any energy level. The value of the Z is quite sensitive to the weight fractions of the elements and the applied interpolation method. Concerning the importance of Z values to medical dosimetry, it is expected that the new data regarding Z values presented here in will be useful, particularly as regards the energy range of interest. (author)

  12. Superconducting transition-edge-microcalorimeter X-ray spectrometer with 2 eV energy resolution at 1.5 keV

    We describe the operation and performance of a prototype microcalorimeter 'energy-dispersive' (non-dispersive) X-ray spectrometer (μcal EDS) developed at NIST for use in X-ray microanalysis and X-ray astronomy. The low-energy microcalorimeter detector, consisting of an Al-Ag bilayer superconducting transition-edge sensor (TES) in thermal contact with a Bi X-ray absorber, is designed for operation in the energy range from 0-2 keV and is fabricated using a shadow-mask lithographic process. The TES microcalorimeter is cooled by a compact adiabatic demagnetization refrigerator and is mounted on a scanning electron microscope. This device achieves a best energy resolution of 2.0±0.1 eV at 1.5 keV, as determined from the analysis of digitized X-ray spectra of a complex glass containing many elements

  13. Study of Radiation Shielding Properties of selected Tropical Wood Species for X-rays in the 50-150 keV Range

    S. Aggrey-Smith

    2016-03-01

    Full Text Available This paper compares the attenuation coefficients of 20 tropical hard wood species based on their linear and mass attenuation and half value layer (HVL properties for X-rays of energy 50–150 keV using a narrow collimated beam from a Cs-137 source. The narrow collimated beam method made corrections from multiple and small-angle scatterings of photons unnecessary. The attenuation depended on the chemical composition and densities of the wood species. The linear attenuation coefficients of wood species at 50–150 keV were highest for Pterygota macrocarpa (4.53 m−1 and lowest for Antiaris africana (1.24 m−1; the mass attenuation coefficient was highest for Triplochiton scleroxylon (17.62 m2/kg and lowest for Nesogordonia papaverifera (2.27 m2/kg.The HVL was highest for Antiaris africana (0.27 m and lowest for Pterygota macrocarpa (0.149 m. Pterygota macrocarpa of about 0.36 m thickness could serve as a more affordable radiation shielding material against secondary scatter and leakage radiations in place of lead, copper or concrete for low X-ray radiations up to 150 keV.

  14. Creation of 2-5 keV and 5-10 keV sky maps using XMM-Newton data

    Savchenko, Denis

    2014-01-01

    Sky maps are powerful visualisation tools for quicklook analysis of extended sources. The latest sky map in soft X-rays (0.1-2.4 keV) has been created in 90ies using ROSAT data. By analyzing publically available data from XMM-Newton X-ray mission we constructed new sky maps in two energy bands -- 2-5 keV and 5-10 keV, complementary to ROSAT data, covering about 1% of all sky, and included them to our web-based tool http://skyview.virgoua.org.

  15. Measurement of attenuation cross-sections of some fatty acids in the energy range 122–1330 keV

    GAIKWAD D K; PAWAR P P

    2016-07-01

    The mass attenuation coefficients $(\\mu m)$ have been measured for undecylic acid (C$_{11}$H$_{22}$O$_2$), lauric acid (C$_{12}$H$_{24}$O$_2$), tridecylic acid (C$_{13}$H$_{26}$O$_2$), myristic acid (C$_{14}$H$_{28}$O$_2$), pentadecylic acid (C$_{15}$H$_{30}$O$_2$) andpalmitic acid (C$_{16}$H$_{32}$O$_2$) using $^{57}$Co, $^{133}$Ba, $^{137}$Cs, $^{60}$Co and $^{22}$Na emitted γ radiation with energies 122, 356,511, 662, 1170, 1275 and 1330 keV, respectively. The accurate values of the effective atomic number (Zeff), atomic cross-section $(\\sigma t,)$, electronic cross-section $(\\sigma e)$ and the effective electron density (Neff) have great significance in radiation protection and dosimetry. These quantities were obtained by utilizing experimentally measured values of mass attenuation coefficients $(\\mu m)$. A NaI(Tl) scintillation detector with 8.2% (at 662 keV) resolution was used for detecting of attenuated γ -photons. The variation in Zeff and Neff of fatty acids with energy is discussed. The experimental and theoretical results are in good agreement within 2% deviation.

  16. The average 0.5-200 keV spectrum of local active galactic nuclei and a new determination of the 2-10 keV luminosity function at z \\approx 0

    Ballantyne, D R

    2013-01-01

    The broadband X-ray spectra of AGNs contains information about the nuclear environment from Schwarzschild radii scales to distances of ~1 pc. In addition, the average shape of the X-ray spectrum is an important input into X-ray background synthesis models. Here, local (z \\approx 0) AGN luminosity functions (LFs) in five energy bands are used as a low-resolution, luminosity-dependent X-ray spectrometer in order to constrain the average AGN X-ray spectrum between 0.5 and 200 keV. The 15-55 keV LF measured by Swift-BAT is assumed to be the best determination of the local LF, and then a spectral model is varied to determine the best fit to the 0.5-2 keV, 2-10 keV, 3-20 keV and 14-195 keV LFs. The spectral model consists of a Gaussian distribution of power-laws with a mean photon-index and cutoff energy E_cut, as well as contributions from distant and disc reflection. The reflection strength is parameterised by varying the Fe abundance relative to solar, A_Fe, and requiring a specific Fe K equivalent width (EW). ...

  17. K+ charge transfer in H2 at low keV collisions

    Alarcón, F. B.; Martinez, H.; Fuentes, B. E.; Yousif, F. B.

    2013-08-01

    Absolute electron capture cross sections for the K+-H2 pair, employing beam collision spectroscopy for 0.4-4 keV energy were measured. The capture cross section increased with the increase in collision energy. The results below 2 keV overlap with previously measured data of other investigators and extend down in energy to 400 eV, where no previous data have been reported. Experimental data were compared with calculations employing the Olson model, which were found to agree in behavior as well as with an absolute value above 100 keV.

  18. Construction and performance test of radiation shielding for 300 keV/20 mA electron beam machine

    The construction and performance test of radiation shielding for 300 keV/20 mA electron beam machine (EBM) has been done. Radiation shielding is used for reduce X-ray radiation which is generated by operation of the EBM, so it is not harmful for people who work in that environment. Radiation shielding plates made of bars of lead (Pb) with a length of 135 cm, 10 cm of width, 2.5 cm of thick and composed a EBM radiation shielding. The plates are made of lead by way of casting and finished mechanically by machine, then installed manually on a frame to form a EBM radiation shielding. In the calculation of thick radiation shield already qualified dose rate limit is set by BAPETEN ≤ 2.5 mrem/hr. The results of the initial test radiation shielding is functioning, it is shown by the results of measurements of the maximum dose rate 0.26 mrem/hr at the operating conditions of EBM with voltage 209 kV and 50 mA of electron beam current. Based on the results test of the construction of radiation shielding are qualified dose rate limit set by BAPETEN. (author)

  19. Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

    Marshall, F. J.; Knauer, J. P.; Anderson, D.; Schmitt, B. L.

    2006-10-01

    The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si (Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this technique to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3keV but has reduced sensitivity above 3keV (˜50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.

  20. Search for galactic sources and bursts of x radiation in the 40-290 keV energy range with a spectrometer of the Kosmos-428 satellite

    Stationary sources and bursts of X-radiation in the 40-290 keV energy range have been found in the cetus constellation as a result of observations carried out with a spectrometer of the ''Kosmos-3428'' satellite

  1. Conceptual design of a 500 keV, 20 MW negative-ion-based neutral beam injector for FER

    A negative-ion-based neutral beam injector is designed conceptually for Fusion Engineering Reactor (FER). The injector is characterized by a long, slender beamline, which is 0.3 - 0.4 m wide, 40 m long, supplying 500 keV, 20 MW neutral beams into the tokamak. Beam divergence is 0.3 degree and such a low divergence is considered to be attainable by using a volume D- ion source because the divergence of 0.8 - 0.9 degree was obtained in our recent experimental results in spite of the low beam energy of 25 keV. Tangential beam injection is possible in this design because of high beam energy and a narrow drift duct. Maintenance of the injector will be easy since beamline components installed near the tokamak are small and simple, and complicated beamline components such as the ion source are situated far from the tokamak. (author)

  2. Measurement of the U-236(n, f) cross section in the neutron energy range from 0.5 eV up to 25 keV

    Wagemans, Cyrillus; De Smet, Liesbeth; Vermote, Sofie; Heyse, Jan

    2008-01-01

    The U-236(n,f) cross section has been measured in the energy range from 0.5 eV to 25 keV at the Geel Electron Linear Accelerator neutron time-of-flight facility of the Institute for Reference Materials and Measurements in Geel, Belgium. A highly enriched U-236 sample was mounted back-to-back with a B-10 sample in the center of a Frisch-gridded ionization chamber, hence realizing a 2 pi detection geometry. A U-235(n,f) cross-section control measurement was performed in the same experimental co...

  3. Measurement of D(d,p)T Reaction Cross Sections in Sm Metal in Low Energy Region (10(≤) Ed(≤)20 keV)

    WANG Tie-Shan; YANG Zhen; H. Yunemura; A. Nakagawa; LV Hui-Yi; CHEN Jian-Yong; LIU Sheng-Jin; J. Kasagi

    2007-01-01

    To study the screening effect of nuclear reactions in metallic environments, the thick target yields, the cross sections and the experimental S(E) factors of the D{d,p)T reaction have been measured on deuterons implanted in Sm metal at 133.2 K for beam energies ranging from 10 to 20keV. The thick target yields of protons emitted in the D(d,p)T reaction are measured and compared with those data extrapolated from cross sections and stopping power data at higher energies. The screening potential in Sm metal at 133.2K is deduced to be 520±56eV. As compared with the value achieved in the gas target, the calculated screening potential values are much larger. This screening potential cannot be simply interpreted only by the electron screening. Energy dependences of the cross section cr(E) and the experimental S(E) factor for D(d,p)T reaction in Sm metal at 133.2K are obtained, respectively.

  4. High Spatial Resolution STXM at 6.2 keV Photon Energy

    Vila-Comamala, Joan; Dierolf, Martin; Kewish, Cameron M.; Thibault, Pierre; Pilvi, Tero; Färm, Elina; Guzenko, Vitaliy; Gorelick, Sergey; Menzel, Andreas; Bunk, Oliver; Ritala, Mikko; Pfeiffer, Franz; David, Christian

    2010-04-01

    We report on a zone-doubling technique that bypasses the electron-beam lithography limitations for the production of X-ray diffractive optics and enables the fabrication of Fresnel zone plates with smaller outermost zone widths than other well-established approaches. We have applied this method to manufacture hard X-ray Fresnel zone plates with outermost zone widths of 25 and 20 nm. These lenses have been tested in scanning transmission X-ray microscopy (STXM) at energies up to 6.2 keV, producing images of test structures that demonstrate a spatial resolution of 25 nm. High spatial resolution STXM images of several biological specimens have been acquired in transmission, dark-field and differential phase contrast modes.

  5. High Spatial Resolution STXM at 6.2 keV Photon Energy

    We report on a zone-doubling technique that bypasses the electron-beam lithography limitations for the production of X-ray diffractive optics and enables the fabrication of Fresnel zone plates with smaller outermost zone widths than other well-established approaches. We have applied this method to manufacture hard X-ray Fresnel zone plates with outermost zone widths of 25 and 20 nm. These lenses have been tested in scanning transmission X-ray microscopy (STXM) at energies up to 6.2 keV, producing images of test structures that demonstrate a spatial resolution of 25 nm. High spatial resolution STXM images of several biological specimens have been acquired in transmission, dark-field and differential phase contrast modes.

  6. ESCA and REELS characterization of electrically conductive polyimide obtained by ion bombardment in the keV range

    Polyimide films were bombarded with Ar+ at 150 keV at various doses from 5 x 1012 to 2 x 1017 ions cm-2. Ion bombardment was found to produce a drastic decrease of the electrical resistivity of the polyimide from about 1016 to 3 x 10-3 Ω cm, the effect being dependent on the ion dose. The chemical structure of the conductive films obtained was characterized by means of ESCA and REELS techniques. The modification of the original polymer seems to proceed at low ion doses (up to 5 x 1014 ions cm-2) by means of the progressive elimination of the carbonyl groups and the related destruction of the imidic rings, while at high doses (from 5 x 1015) ions cm-2) the carbonization of the polyimide occurs with the production of an amorphous carbon still containing significant amount of residual N and O atoms. (author)

  7. Attenuation coefficients of soils and some building materials of Bangladesh in the energy range 276-1332 keV

    The linear and mass attenuation coefficients of different types of soil, sand, building materials and heavy beach mineral samples from the Chittagong and Cox's Bazar area of Bangladesh were measured using a high-resolution HPGe detector and the γ-ray energies 276.1, 302.8, 356.0, 383.8, 661.6 and 1173.2 and 1332.5 keV emitted from point sources of 133Ba, 137Cs and 60Co, respectively. The linear attenuation coefficients show a linear relationship with the corresponding densities of the samples studied. The variations of the mass attenuation coefficient with γ-ray energy were exponential in nature. The measured mass attenuation coefficient values were compared with measurements made in other countries for similar kinds of materials. The values are in good agreement with each other in most cases

  8. Attenuation coefficients of soils and some building materials of Bangladesh in the energy range 276-1332 keV.

    Alam, M N; Miah, M M; Chowdhury, M I; Kamal, M; Ghose, S; Rahman, R

    2001-06-01

    The linear and mass attenuation coefficients of different types of soil, sand, building materials and heavy beach mineral samples from the Chittagong and Cox's Bazar area of Bangladesh were measured using a high-resolution HPGe detector and the gamma-ray energies 276.1, 302.8, 356.0, 383.8, 661.6 and 1173.2 and 1332.5 keV emitted from point sources of 133Ba, 137Cs and 60Co, respectively. The linear attenuation coefficients show a linear relationship with the corresponding densities of the samples studied. The variations of the mass attenuation coefficient with gamma-ray energy were exponential in nature. The measured mass attenuation coefficient values were compared with measurements made in other countries for similar kinds of materials. The values are in good agreement with each other in most cases. PMID:11300413

  9. Simulation of electron tracks in the energy range of 0.01 to 10 keV in water vapour

    The primary aim of this study was to develop a numerical program for simulating electron traces in steam for the energy range of 0.01 to 10 keV, and to prove the quality of the simulation by comparing calculations with measurements from current literature. Moreover, the application range of the program was to be shown by means of practical examples. The task could be performed by applying the Platzman method for analyzing experimental data with respect to their necessary consistency with established theoretical knowledge. The differential oscillator strength distribution, major differential ionization cross-sections and cross-sections for excitation and elastic collision were derived. By comparing major integral factors (e.g., W value (Co80)) with calculated results, it was possible to determine, e.g., the secondary electron cross-sections with the help of consistency tests. These derived activation cross-sections were used as the core of a Monte Carlo calculation programme (MOCA 87) for simulating electron trace structures which were evaluated in such a way that various calculation values could be compared critically with values obtained experimentally (e.g., for yields, depth and radial dose curves, micro-dosimetric distribution). On the whole, the programme exhibited sufficient consistency. (orig./HP)

  10. SURVIVAL DEPTH OF ORGANICS IN ICES UNDER LOW-ENERGY ELECTRON RADIATION ({<=}2 keV)

    Barnett, Irene Li; Lignell, Antti; Gudipati, Murthy S., E-mail: gudipati@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-301, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2012-03-01

    Icy surfaces in our solar system are continually modified and sputtered with electrons, ions, and photons from solar wind, cosmic rays, and local magnetospheres in the cases of Jovian and Saturnian satellites. In addition to their prevalence, electrons specifically are expected to be a principal radiolytic agent on these satellites. Among energetic particles (electrons and ions), electrons penetrate by far the deepest into the ice and could cause damage to organic material of possible prebiotic and even biological importance. To determine if organic matter could survive and be detected through remote sensing or in situ explorations on these surfaces, such as water ice-rich Europa, it is important to obtain accurate data quantifying electron-induced chemistry and damage depths of organics at varying incident electron energies. Experiments reported here address the quantification issue at lower electron energies (100 eV-2 keV) through rigorous laboratory data analysis obtained using a novel methodology. A polycyclic aromatic hydrocarbon molecule, pyrene, embedded in amorphous water ice films of controlled thicknesses served as an organic probe. UV-VIS spectroscopic measurements enabled quantitative assessment of organic matter survival depths in water ice. Eight ices of various thicknesses were studied to determine damage depths more accurately. The electron damage depths were found to be linear, approximately 110 nm keV{sup -1}, in the tested range which is noticeably higher than predictions by Monte Carlo simulations by up to 100%. We conclude that computational simulations underestimate electron damage depths in the energy region {<=}2 keV. If this trend holds at higher electron energies as well, present models utilizing radiation-induced organic chemistry in icy solar system bodies need to be revisited. For interstellar ices of a few micron thicknesses, we conclude that low-energy electrons generated through photoionization processes in the interstellar medium

  11. High-accuracy determination of the relative full energy peak efficiency curve of a coaxial HPGe detector in the energy range 700-1300 keV

    A method for the high-accuracy determination of the relative full energy peak efficiency is established. Radionuclides that emit at least two gamma-ray lines for which the relative intensity can be found (from the decay scheme) to much better than ±0.1% were used as calibration standards. Specifically, the 889 and 1120 keV lines of 46Sc, the 983 and 1312 keV lines of 48Sc, the 1173 and 1332 keV lines of 60Co, and the 702 and 871 keV lines of 94Nb were implemented. The high-accuracy calibration was taken to extend from the lowest line of 94Nb at 702 keV to the highest line of 60Co at 1332 keV. An analytical expression, based on linear least-squares fitting, was developed to describe the behavior of the relative efficiency curve in that energy range. As a result, the ability of predicting relative full energy peak efficiencies to within ±0.1% (over most of the energy range) was demonstrated. The presented method is applicable in any measurement that requires the minimum calibration bias in the determination of reaction rate ratios. Applications in neutron activation analysis (NAA) and in nuclear reactor dosimetry represent examples of such situations. (orig.)

  12. Inelastic processes in Na$^{+}-$Ne, Ar and Ne$^{+},$ Ar$^{+}-$Na collisions in energy range $0.5-14$ keV

    Lomsadze, R A; Kezerashvili, R Ya

    2015-01-01

    Absolute cross sections for charge-exchange, ionization and excitation in Na$% ^{+}-$Ne and Na$^{+}-$Ar collisions were measured in the ion energy range $% 0.5-10$ keV using a refined version of a capacitor method, and collision and optical spectroscopy methods simultaneously in the same experimental set-up. Ionization cross sections for Ne$^{+}-$Na and Ar$^{+}-$Na collisions are measured at the energies of $2-14$ keV using a crossed-beam spectroscopy method. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. For the charge-exchange process in Na$^{+}$ $-$Ar collisions two nonadiabatic regions are revealed and mechanisms responsible for these regions are explained. Structural peculiarity on the excitation function for the resonance lines of argon atoms in Na$^{+}$ $-$Ar collisions are observed and the possible mechanisms of this phenomenon are explored. The measured ionization cross sections for Na$^{+}-$Ne and Ne$^{+}-$Na collisi...

  13. Proposed experiments to detect keV range sterile neutrinos using energy-momentum reconstruction of beta decay or K-capture events

    Smith, Peter F

    2016-01-01

    Sterile neutrinos in the keV mass range may constitute the galactic dark matter. Various proposed direct detection and laboratory searches are reviewed. The most promising method in the near future is complete energy-momentum reconstruction of individual beta-decay or K-capture events, using atoms suspended in a magneto-optical trap. A survey of suitable isotopes is presented, together with the measurement precision required in a typical experimental configuration. It is concluded that among the most promising are the K-capture isotopes 131Cs, which requires measurement of an X-ray and several Auger electrons in addition to the atomic recoil, and 7Be which has only a single decay product but needs development work to achieve a trapped source. A number of background effects are discussed. It is concluded that sterile neutrinos with masses down to the 5-10 keV region would be detectable, together with relative couplings down to the level 10-10-10-11 in a 1-2 year running time.

  14. The Mont Blanc mystery solved? A $m^2=-0.28 keV^2$ neutrino

    Ehrlich, Robert

    2016-01-01

    Evidence is presented in support of a hypothesis made in 2013 predicting the existence of a tachyonic neutrino mass eigenstate doublet having $m^2\\approx -0.2 keV^2$ with $\\Delta m^2=1 eV^2.$ The evidence is based primarily on the puzzling LSD (Mont Blanc) neutrino burst observed on February 23, 1987, which the hypothesis thoroughly explains, with additional support from the Kamiokande-II events recorded on the same day. The probability of the null hypothesis, i.e., that background fluctuations can explain the noted features of the two data sets is estimated to be $4.2\\sigma$ (Mont Blanc), and $3.7\\sigma$ (K-II). Such a controversial hypothesis as a tachyonic neutrino requires absolutely definitive proof, and there may exist a test based on observing the neutrino spectrum from diffuse supernovae that could supply it.

  15. The BeppoSAX 2-10 keV Survey

    Giommi, P; Fiore, F

    2000-01-01

    We present the results of a 2-10 keV BeppoSAX survey based on 140 high galactic latitude MECS fields, 12 of which are deep exposures of ``blank'' parts of the sky. The limiting sensitivity is 5 10^-14 erg cm^-2 s^-1 where about 25% of the Cosmic X-ray Background (CXB) is resolved into discrete sources. The logN-logS function, built with a statistically complete sample of 177 sources, is steep and in good agreement with the counts derived from ASCA surveys. A CXB fluctuation analysis allowed us to probe the logN-logS down to about 1.5 10^-14 erg cm^-2 s^-1 where the contribution of discrete sources to the CXB grows to 40-50%. A hardness ratio analysis reveals the presence of a wide range of spectral shapes and that a fairly large fraction of sources appear to be heavily absorbed, some of which showing soft components. A comparison of the flux distribution of different subsamples confirms the existence of a spectral hardening with decreasing flux. This effect is probably due to an increasing percentage of absor...

  16. Neutron-induced fission cross section of 237Np in the keV to MeV range at the CERN n_TOF facility

    Diakaki, M.; Karadimos, D.; Vlastou, R.; Kokkoris, M.; Demetriou, P.; Skordis, E.; Tsinganis, A.; Abbondanno, U.; Aerts, G.; Álvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Bečvář, F.; Berthoumieux, E.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Capote, R.; Carrillo de Albornoz, A.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; David, S.; Dolfini, R.; Domingo-Pardo, C.; Dorochenko, A.; Dridi, W.; Duran, I.; Eleftheriadis, Ch.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fuji, K.; Furman, W.; Goncalves, I.; Gallino, R.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Ioannidis, K.; Isaev, S.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karamanis, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Kolokolov, D.; Konovalov, V.; Krtička, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Oshima, M.; Pancin, J.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Sedysheva, M.; Stamoulis, K.; Stephan, C.; Tagliente, G.; Tain, J. L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Voss, F.; Wendler, H.; Wiescher, M.; Wisshak, K.; n TOF Collaboration

    2016-03-01

    The neutron-induced fission cross section of 237Np was experimentally determined at the high-resolution and high-intensity facility n_TOF, at CERN, in the energy range 100 keV to 9 MeV, using the 235U(n ,f ) and 238U(n ,f ) cross section standards below and above 2 MeV, respectively. A fast ionization chamber was used in order to detect the fission fragments from the reactions and the targets were characterized as far as their mass and homogeneity are concerned by means of α spectroscopy and Rutherford backscattering spectroscopy respectively. Theoretical calculations within the Hauser-Feshbach formalism have been performed, employing the empire code, and the model parameters were tuned in order to successfully reproduce the experimental fission cross-sectional data and simultaneously all the competing reaction channels.

  17. Energy dependence of some neutron detector sensitivity in the energy range from 17 keV up to 1 MeV

    The results of experimental determination of sensitivity of neutron detectors used as dosimeters in the energy range from 17 keV to 1 MeV are presented. The measurements were performed in the EhG-2.5 accelerator. Monoenergetic neutrons were produced in the T (p, n)3He reaction at different proton energies. The detectors were placed at angles from 30 deg to 120 deg to proton beam direction. The detector sensitivity was evaluated by comparison of their values with those of the OVC-3M standard neutron counter. The obtained results could be used for determining energy dependences of sensitivities of detectors under study and for evaluating the errors of measurements of neutron doses in the radiation fields behind nuclear-physical installation shielding

  18. The High Energy Emission of the Crab Nebula from 20 keV to 6 MeV with INTEGRAL

    Jourdain, E

    2009-01-01

    The SPI spectrometer aboard the INTEGRAL mission observes regularly the Crab Nebula since 2003. We report on observations distributed over 5.5 years and investigate the variability of the intensity and spectral shape of this remarkable source in the hard X-rays domain up to a few MeV. While single power law models give a good description in the X-ray domain (mean photon index ~ 2.05) and MeV domain (photon index ~ 2.23), crucial information are contained in the evolution of the slope with energy between these two values. This study has been carried out trough individual observations and long duration (~ 400 ks) averaged spectra. The stability of the emission is remarkable and excludes a single power law model. The slopes measured below and above 100 keV agree perfectly with the last values reported in the X-ray and MeV regions respectively, but without indication of a localized break point. This suggests a gradual softening in the emission around 100 keV and thus a continuous evolution rather than an actual c...

  19. Thorium resonance-neutron capture (2.6 to 10 keV)

    Individual resonance parameters are fitted to thorium neutron capture data up to 10 keV. The ENDF/B-V resonance parameters (given up to 4 keV) do not describe the data well. An average radiation width GAMMA/sub γ/ = 25.5 +- 1.2 meV is derived together with fitted strength functions 104S0 = (0.86 +- 0.10) eV/sup -1/2/, 104S1 = (1.48 +- 0.07) eV/sup -1/2/, 104S2 = (1.12 +- 0.06) eV/sup -1/2/, and 104GAMMA/sub γ/-bar/D/sub l = 0/ = 14.7 +- 0.5. 2 figures, 2 tables

  20. Calorimetry for dose measurement at electron accelerators in the 80-120 keV energy range

    Helt-Hansen, J.; Miller, A.; Duane, S.;

    2005-01-01

    Calorimeters for dose measurement at low-energy electron accelerator energies (80-120 keV) are described. Three calorimeters with different characteristics were designed and their dose response and measurement uncertainties were characterized. The heated air between the beam exit window and the c...

  1. Conceptual design of negative-ion-based 500 keV, 20 MW neutral beam injector

    The conceptual design of the source plasma generator and the accelerating system is presented. Three candidate systems are then examined, each with a different neutralizing cell. The system having a very long neutralizer was judged to be the most suitable to the reactor considered. It was designed in detail. The long neutralizer (30 m) has many advantages: (1) the ion source can be located far from the reactor, permitting a narrow injection tube and tangential injection angle; (2) neutron shielding is easy because the solid angle of the beam line is very small; (3) complex components are removed from the vicinity of the reactor

  2. Mass attenuation coefficients of Martian meteorites and Earth composition in the energy range 1 keV-100 GeV

    Ün, M.; Han, E. Narmanli; Ün, A.

    2016-04-01

    Mass attenuation coefficients for 24 Martian meteorites have been determined in the energy range from 1 keV to 100 GeV. The values of mass attenuation coefficients (µ/ρ) of the samples were calculated the WINXCOM program. The obtained results for Martian meteorites have been compared with the results for Earth composition and similarities or differences also evaluated.

  3. The BeppoSAX 2-10 keV survey

    Giommi, P.; Perri, M.; Fiore, F.

    2000-10-01

    We present the results of a 2-10 keV BeppoSAX survey based on 140 high galactic latitude MECS fields, 12 of which are deep exposures of ``blank'' parts of the sky. The limiting sensitivity is 5*E-14 erg cm -2s-1 where about 25% of the Cosmic X-ray Background (CXB) is resolved into discrete sources. The logN-logS function, built with a statistically complete sample of 177 sources, is steep and in good agreement with the counts derived from ASCA surveys. A CXB fluctuation analysis allowed us to probe the logN-logS down to about 1.5*E-14 erg cm -2s-1 where the contribution of discrete sources to the CXB grows to ~ 40-50%. A hardness ratio analysis reveals the presence of a wide range of spectral shapes and that a fairly large fraction of sources appear to be heavily absorbed, some of which showing soft components. A comparison of the flux distribution of different subsamples confirms the existence of a spectral hardening with decreasing flux. This effect is probably due to an increasing percentage of absorbed sources at faint fluxes, rather than to a gradual flattening of the spectral slope. Nearly all the sources for which adequate ROSAT exposures exist, have been detected in the soft X-rays. This confirms that soft spectral components are present even in strongly absorbed objects, and that a large population of sources undetectable below a few keV does not exist. A Ve/Va test provides evidence for the presence of cosmological evolution of a magnitude similar to that found in soft X-ray extragalactic sources. Evolution is present both in normal and absorbed sources, with the latter population possibly evolving faster, although this effect could also be the result of complex selection effects. Table 1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  4. Absolute Doubly Differential Cross Sections for Ejection of Electrons in - and Five-Body Collisions of 20 TO 114-KEV Protons on Atomic and Molecular Hydrogen.

    Kerby, George W., III

    A crossed-beam experiment was performed to detect ejected electrons from ground-state atomic and molecular hydrogen after collisions with 20- to 114-keV protons. Because a pure atomic hydrogen target is not readily attainable, a method has been devised which yields atomic to molecular hydrogen doubly differential cross section (DDCS) ratios. Since the molecular hydrogen DDCS's were independently measured, the atomic cross sections could be directly calculated. Absolute cross sections differential in electron energy and angle were measured for electron energies ranging from 1.5 to 400 eV and scattering angles from 15^circ to 165^circ with respect to the fast beam. Electrons and ions were energy analyzed by an electrostatic hemispherical analyzer, which has an energy resolution of 5% and is rotatable in the scattering plane about the collision center. Atomic hydrogen is produced by a radio-frequency discharge of the type devised by J. Slevin. Hydrogen gas effuses from a 1 mm diameter nozzle in a nearly cos theta distribution. The projectile beam intersects the thermal gas targets 4 mm below the tip of the nozzle. Dissociation fractions of 74% and atomic hydrogen densities of 7 times 10 ^{11} cm^ {-3} were typical. The fraction of dissociated hydrogen was measured by detecting the reduced 9-eV ion signal from the molecular target when the RF is on. This characteristic ion signal originates from the coulomb breakup of the molecule and dissociative channels of excited H _sp{2}{+}. An auxiliary experiment was performed to determine the target densities with the aid of a low-resolution magnetic mass spectrometer after the slow recoil ions were extracted from the collision volume by a weak electric field. Comparisons of the atomic cross sections are made with theories such as the classical-trajectory Monte Carlo (CTMC) method, the plane-wave Born approximation (PWBA) and the continuum-distorted-wave eikonal-initial-state (CDW-EIS) approximation.

  5. Web 2.0

    Han, Sam

    2012-01-01

    Web 2.0 is a highly accessible introductory text examining all the crucial discussions and issues which surround the changing nature of the World Wide Web. It not only contextualises the Web 2.0 within the history of the Web, but also goes on to explore its position within the broader dispositif of emerging media technologies.The book uncovers the connections between diverse media technologies including mobile smart phones, hand-held multimedia players, ""netbooks"" and electronic book readers such as the Amazon Kindle, all of which are made possible only by the Web 2.0. In addition, Web 2.0 m

  6. Determination of the effective atomic numbers and electron densities for YBaCuO superconductor in the range 59.5-136 keV

    The effective atomic numbers and electron densities of YBa2Cu3O7-δ superconductor at 59.5, 65.2, 77.1, 94.6, 122 and 136 keV were calculated by using the measured mass attenuation coefficients. Measurements were made by performing transmission experiments in a well-collimated narrow beam geometry set-up by employing Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. These values are found to be in good agreement with theoretical values calculated based on XCOM data. The observed crystal structure of YBa2Cu3O7-δ superconductor is close to the theoretical structure. Zeff and Nel experimental values showed good agreement with the theoretical values for calcined and sintered YBa2Cu3O7-δ

  7. Determination of the effective atomic numbers and electron densities for YBaCuO superconductor in the range 59.5 136 keV

    Baltaş, H.; Çevik, U.

    2008-04-01

    The effective atomic numbers and electron densities of YBa 2Cu 3O 7-δ superconductor at 59.5, 65.2, 77.1, 94.6, 122 and 136 keV were calculated by using the measured mass attenuation coefficients. Measurements were made by performing transmission experiments in a well-collimated narrow beam geometry set-up by employing Si(Li) detector with a resolution of 0.16 keV at 5.9 keV. These values are found to be in good agreement with theoretical values calculated based on XCOM data. The observed crystal structure of YBa 2Cu 3O 7-δ superconductor is close to the theoretical structure. Zeff and Nel experimental values showed good agreement with the theoretical values for calcined and sintered YBa 2Cu 3O 7-δ.

  8. A compact flat-response x-ray detector for the radiation flux in the range from 1.6 keV to 4.4 keV

    A band-pass flat-response x-ray detector is designed to measure the absolute M-band x-ray flux. The detector comprises an x-ray diode and a compound filter that is carefully designed to achieve the desired response function in the range from 1.6 to 4.4 keV, i.e. the flatness of the spectral response is better than 5%. The designed response function is in excellent agreement with the calibrated one, indicating that the x-ray detector with various responses can be achieved with the state-of-art fabrication technique. (paper)

  9. Investigation on ultracold RbCs molecules in (2)0+ long-range state below the Rb(5S1/2) + Cs(6P1/2) asymptote by high resolution photoassociation spectroscopy

    We present high resolution photoassociation spectroscopy of RbCs molecules in (2)0+ long-range state below the Rb(5S1/2) + Cs(6P1/2) asymptote and derive the corresponding C6 coefficient, which is used to revise the potential energy curves. The excited state molecules are produced in a dual-species dark spontaneous force optical trap and detected by ionizing ground state molecules after spontaneous decay, using a high sensitive time-of-flight mass spectrum. With the help of resonance-enhanced two-photon ionization technique, we obtain considerable high resolution photoassociation spectrum with rovibrational states, some of which have never been observed before. By applying the LeRoy-Bernstein method, we assign the vibrational quantum numbers and deduce C6 coefficient, which agrees with the theoretical value of A1Σ+ state correlated to Rb(5S1/2) + Cs(6P1/2) asymptote. The obtained C6 coefficient is used to revise the long-range potential energy curve for (2)0+ state, which possesses unique A − b mixing characteristic and can be a good candidate for the production of absolutely ground state molecule

  10. Improved energies for the 5.2 keV M1 and 42.0 keV M2 nuclear transitions in {sup 83}Rb

    Inoyatov, A.Kh. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); National University, Institute of Applied Physics, Tashkent (Uzbekistan); Rysavy, M. [Nuclear Physics Institute of the ASCR, Rez (Czech Republic); Kovalik, A. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Nuclear Physics Institute of the ASCR, Rez (Czech Republic); Filosofov, D.V.; Yushkevich, Yu.V. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Zhdanov, V.S. [Nuclear Physics Institute, Almaty (Kazakhstan)

    2014-03-15

    The low-energy electron spectrum following the decay of {sup 83}Sr was analysed at high instrumental resolution by an electrostatic spectrometer. Significantly improved energies of 5235.7 ± 0.8 and 42078.0 ± 1.8 eV were determined from the conversion electron spectra for the nuclear transitions depopulating the first 3/2{sup -} and the second 9/2{sup +} excited states in {sup 83}Rb to the 5/2{sup -} ground state, respectively. The M1 character for the 5.2 keV nuclear transition was confirmed and the E2 admixture parameter δ{sup 2}(E2/M1) = (2.6 ± 0.2) x 10{sup -5} was obtained. Values of 2.8 ± 0.2, 3.8 ± 0.2, 1.4 ± 0.3, 1.4 ± 0.4, and 4.1 ± 0.3 eV were determined for the K, L{sub 1}, L{sub 2}, L{sub 3}, and M{sub 1} natural atomic level widths of rubidium, respectively. (orig.)

  11. Studies on the attenuation coefficients of some egyptian materials In the energy range 81-1332.5 KeV

    The linear and mass attenuation coefficients for different types of soil, sand and some building material samples at Inshas site in Egypt were investigated. The measurements were performed using gamma rays spectrometer consists of hyper pure germanium (HPGe) detector. The attenuation coefficients values were determined at the y-rays energies 81.0, 276.4, 302.8, 356.0 and 383.9 KeV of l33Ba, 661.7 KeV of 137Cs and 1173.4 and 1332.5 KeV of 60Co. The tested samples were dried, sieved to different particle sizes. The effect of cement to sand ratio on the attenuation coefficient values was studied. The results obtained showed that there was no specific relation between the mass attenuation coefficients and samples densities, but there was exponential decay relation between the mass attenuation coefficients and the gamma rays energy. There were variations of the values of the mass attenuation coefficients with the γ-rays energy. The obtained values for mass attenuation coefficients were compared with other values in different countries. These values agreed with some values and differed with others, because there are differences in the elemental components of each sample

  12. Electron-transfer reactions of fast Xe/sup n/+ ions with Xe in the energy range 15 keV to 1.6 MeV

    Electron-transfer cross sections for the reactions of Xe/sup n/+ (n = 1--4) with Xe atoms have been determined as a function of projectile-ion kinetic energy in the range 15 keV--1.6 MeV. For Xe/sup n/+ (n = 2, 3, 4), cross sections for sequential transfer of two or more electrons in single-ion--atom collisions have been obtained. These cross sections decrease with increasing number of electrons transferred. The observed insensitivity of cross sections to projectile kinetic energy in the range investigated follows the condition that the linear velocity of the ion is less than the orbital velocity of a valence electron in the slow-moving target atom. Attenuation cross sections for reactions of Xe/sup n/+ (n = 2, 3, 4) follow approximately a Z2/sub direct-sum/ charge dependence. A simple classical model based on Coulomb forces yields cross sections with a reasonable fit to the experimental data

  13. The Morphology of the X-ray Emission above 2 keV from Jupiter's Aurorae

    Elsner, R.; Branduardi-Raymont, G.; Galand, M.; Grodent, D.; Gladstone, G. R.; Waite, J. H.; Cravens, T.; Ford, P.

    2007-01-01

    The discovery in XMM-Newton X-ray data of X-ray emission above 2 keY from Jupiter's aurorae has led us to reexamine the Chandra ACIS-S observations taken in Feb 2003. Chandra's superior spatial resolution has revealed that the auroral X-rays with E > 2 keV are emitted from the periphery of the region emitting those with E < 1 keV. We are presently exploring the relationship of this morphology to that of the FUV emission from the main auroral oval and the polar cap. The low energy emission has previously been established as due to charge exchange between energetic precipitating ions of oxygen and either sulfur or carbon. It seems likely to us that the higher energy emission is due to precipitation of energetic electrons, possibly the same population of electrons responsible for the FUV emission. We discuss our analysis and interpretation.

  14. The average 0.5-200 keV spectrum of local active galactic nuclei and a new determination of the 2-10 keV luminosity function at z ≈ 0

    Ballantyne, D. R.

    2014-01-01

    The broad-band X-ray spectra of active galactic nuclei (AGNs) contains information about the nuclear environment from Schwarzschild radii scales (where the primary power law is generated in a corona) to distances of ˜1 pc (where the distant reflector may be located). In addition, the average shape of the X-ray spectrum is an important input into X-ray background synthesis models. Here, local (z ≈ 0) AGN luminosity functions (LFs) in five energy bands are used as a low-resolution, luminosity-dependent X-ray spectrometer in order to constrain the average AGN X-ray spectrum between 0.5 and 200 keV. The 15-55 keV LF measured by Swift-BAT is assumed to be the best determination of the local LF, and then a spectral model is varied to determine the best fit to the 0.5-2 keV, 2-10 keV, 3-20 keV and 14-195 keV LFs. The spectral model consists of a Gaussian distribution of power laws with a mean photon-index and cutoff energy Ecut, as well as contributions from distant and disc reflection. The reflection strength is parametrized by varying the Fe abundance relative to solar, AFe, and requiring a specific Fe Kα equivalent width (EW). In this way, the presence of the X-ray Baldwin effect can be tested. The spectral model that best fits the four LFs has = 1.85 ± 0.15, E_{cut}=270^{+170}_{-80} keV, A_{Fe}=0.3^{+0.3}_{-0.15}. The sub-solar AFe is unlikely to be a true measure of the gas-phase metallicity, but indicates the presence of strong reflection given the assumed Fe Kα EW. Indeed, parametrizing the reflection strength with the R parameter gives R=1.7^{+1.7}_{-0.85}. There is moderate evidence for no X-ray Baldwin effect. Accretion disc reflection is included in the best-fitting model, but it is relatively weak (broad iron Kα EW BAT and RXTE. We therefore present a new determination of the local 2-10 keV LF that is consistent with all other energy bands, as well as the de-evolved 2-10 keV LF estimated from the XMM-Newton Hard Bright Survey. This new LF should be used

  15. A satellite-borne ion mass spectrometer for the energy range 0 to 16 keV

    The Ion Composition Experiment (ICE) on GEOS represents the first comprehensive attempt to measure the positive ion composition at high altitudes in the magnetosphere. Due to the heterogeneous nature of the magnetospheric plasma a novel mass spectrometer has been developed to cover the mass per charge range from 1H+ to beyond 138Ba+ and the energy per charge range from 0 to 16 keV/e. The ICE consists primarily of a cylindrical electrostatic analyzer followed by a curved analyzer incorporating crossed magnetic and electric fields. This combination has limited angular and energy focussing properties, but it maintains a mass resolution of about 4 over a wide range in energy and mass, sufficient for the objectives of measuring plasmas of both solar and terrestrial origin. High sensitivity and low background should allow measurements of rarer ion constituents, such as 3He2+ and 16O6+, down to flux levels of 10-2 ions (cm2 sec ster eV)-1. The unusually large mass range offers the possibility of identifying Li+ or Ba+ tracer ions which may be injected into the magnetosphere by active experiments. A sophisticated electronics combined with powerful ground computer and telecommand systems allow for very efficient scanning of the mass-energy space. Based on survey measurements a variety of special modes can be commanded, either manually or automatically by means of the ground station computer. (Auth.)

  16. What can BeppoSAX do about the 2-10 keV cosmic background ? A progress report

    Chiappetti, L; Del Sordo, S; Maccarone, M C; Mineo, T; Molendi, S

    1997-01-01

    We report the current status of the analysis of the MECS background using the entire dataset of the BeppoSAX Science performance Verification Phase. We have collected 360 ks of dark Earth instrumental background, 470 ks of bright Earth background and 1100 ks of blank field data. We are attempting to model the instrumental background in terms of its various components (in particular the spatial modulation of the residual contamination by the built-in Fe calibration sources), and then use this model, and the information on the vignetting and the PSF to derive the cosmic background in the 2-10 keV range

  17. Study of Radiation Shielding Properties of selected Tropical Wood Species for X-rays in the 50-150 keV Range

    S. Aggrey-Smith; K. Preko; F. W. Owusu; J.K. Amoako

    2016-01-01

    This paper compares the attenuation coefficients of 20 tropical hard wood species based on their linear and mass attenuation and half value layer (HVL) properties for X-rays of energy 50–150 keV using a narrow collimated beam from a Cs-137 source. The narrow collimated beam method made corrections from multiple and small-angle scatterings of photons unnecessary. The attenuation depended on the chemical composition and densities of the wood species. The linear attenuation coefficients of wood ...

  18. ARLearn 2.0

    Ternier, Stefaan; Tabuenca, Bernardo; Klemke, Roland; Specht, Marcus

    2013-01-01

    Ternier, S., Tabuenca, B., Klemke, R., & Specht, M. (2012). ARLearn (version 2.0) [Software]. Heerlen, The Netherlands: Open Universiteit. Available under the GNU Lesser General Public License (LGPL3)

  19. Polarization evidence for the isotropy of electrons responsible for the production of 5-20 keV X-rays in solar flares

    Tramiel, L. J.; Novick, R.; Chanan, G. A.

    1984-05-01

    We have flown a solar flare X-ray polarimeter on the third flight (STS 3) of the Space Shuttle Columbia as part of the OSS-1 pallet of instruments. We observed eight solar flares in the 5-20 keV band on 1982 March 28. The signal-to-background ratio in all cases exceeded 25. A preflight contamination problem invalidated the earlier laboratory calibration, and the instrument had to be calibrated in-flight against two flares near the center of the solar disk, which are expected to be unpolarized on geometric grounds in a variety of models. No statistically significant polarization was then detected in any of the other six flares. Upper limits (99% confidence level) range from 2.5% to 12.7%. For two of the observed flares these results disagree with the predictions of a simple radially beamed, linear bremsstrahlung model at greater than 99% confidence. One of these flares had a hard impulsive burst; the measured upper limit on this burst (10%) also disagrees with the predictions of the beamed hypothesis. If the calibration flares were polarized, then the above upper limits can be interpreted as limits on the changes in polarization from flare to flare. Because the observed flares spanned a large longitude range and because the predictions of the beamed models depend fairly sensitively on viewing angle, the small relative polarizations are still difficult to reconcile with simple beamed models. The results are also compared with recent, more sophisticated models of Leach and Petrosian, which generally predict lower polarizations. We find that the observations are marginally inconsistent with a model in which the electrons are initially strongly beamed, but subsequently become largely isotropic as a result of the effects of a converging magnetic field; they are consistent with a model in which the electrons are injected isotropically, but in which the preference for motion along the magnetic field lines is explicitly taken into account. The results are also consistent

  20. An improved long counter for neutron fluence measurement with a flat response over a wide energy range from 1 keV to 15 MeV

    A new long counter has been developed with a flat energy response over a wide range from 1 keV to 15 MeV. It consists of five 3He proportional counter tubes and a number of carefully designed polyethylene moderators. The structure of this detector was determined by careful Monte Carlo simulations. The calculated results show that the efficiency of this counter is uniform from 1 keV neutron energy to 15 MeV. Calibration was performed on an Am–Be source and the accelerator-produced monoenergetic D–D and D–T neutron sources. Fluctuation of the response curve is less than 10% over this energy range

  1. Comparison of Martian meteorites with earth composition: Study of effective atomic numbers in the energy range 1 keV-100 GeV

    Ün, Adem; Han, Ibrahim; Ün, Mümine

    2016-04-01

    Effective atomic (Zeff) and electron numbers (Neff) for 24 Martian meteorites have been determined in the energy range from 1 keV to 100 GeV and also for sixteen significant energies of commonly used radioactive sources. The values of Zeff and Neff for all sample were obtained from the DirectZeff program. The obtained results for Martian meteorites have been compared with the results for Earth composition and similarities or differences also evaluated.

  2. Construction, calibration and testing of a ionization chamber for exposure measurement of X and gamma rays in the energy range from 40 keV up to 1250KEV

    An unsealed thimble ionization chamber with connecting cable was designed, manufactured and tested at the IRD/CNEN, for exposure or exposure rate measurement of X or gamma rays in the energy range from 40 keV up to Cobalt-60. Recommendations given by IEC,TC-62(1974) were used as acceptance tests of the ionization chamber for use as a tertiary standard (field class instruments) in radiation therapy. In addition, intercomparison with commercially available chambers of reference class type were carried out in respect to field size dependence, energy dependence, short and long term stability.The results of those tests indicated the usefulness of the developed ionization chamber as a tertiary standard. (author)

  3. Study of fission product γ spectra in the band 2-500 keV

    In the study of the γ spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author)

  4. The Fano factor in gaseous xenon: A Monte Carlo calculation for X-rays in the 0.1 to 25 keV energy range

    A calculation of the Fano factor for gaseous xenon is carried out using a detailed Monte Carlo simulation of the absorption of X-rays in the 0.1 to 25 keV energy range. This factor is found to be energy dependent with values ranging from 0.17 to 0.32 and has sharp increases near the xenon absorption edges. An interpretation of the calculated results is made in terms of the relative importance of photoelectron and Auger/Coster-Kronig cascading electron processes. (orig.)

  5. Dissociative ionization cross sections of CO2 at electron impact energy of 5 keV

    The dissociative ionization of CO2 induced by 5 keV electrons in two-body and three-body dissociative channels of CO22+ and CO23+ is identified by the ion—ion coincidence- method using a momentum imaging spectrometer. The partial ionization cross sections (PICSs) of different ionic fragments are measured and the results generally agree with the calculations made by a semi-empirical approach. Furthermore, the PICSs of the dissociative channels are also obtained by carefully considering the detection efficiency of the micro-channel plates and the total transmission efficiency of the time of flight system. (atomic and molecular physics)

  6. Energy response of GR-200A thermoluminescence dosemeters to 60Co and to monoenergetic synchrotron radiation in the energy range 28-40 keV.

    Emiro, F; Di Lillo, F; Mettivier, G; Fedon, C; Longo, R; Tromba, G; Russo, P

    2016-01-01

    The response of LiF:Mg,Cu,P thermoluminescence dosemeters (type GR-200A) to monoenergetic radiation of energy 28, 35, 38 and 40 keV was evaluated with respect to irradiation with a calibrated (60)Co gamma-ray source. High-precision measurements of the relative air kerma response performed at the SYRMEP beamline of the ELETTRA synchrotron radiation facility (Trieste, Italy) showed a significant deviation of the average response to low-energy X-rays from that to (60)Co, with an over-response from 6 % (at 28 keV) to 22 % (at 40 keV). These data are not consistent with literature data for these dosemeters, where model predictions gave deviation from unity of the relative air kerma response of about 10 %. The authors conclude for the need of additional determinations of the low-energy relative response of GR-200A dosemeters, covering a wider range of monoenergetic energies sampled at a fine energy step, as planned in future experiments by their group at the ELETTRA facility. PMID:25737582

  7. THE HIGH-ENERGY EMISSION OF THE CRAB NEBULA FROM 20 keV TO 6 MeV WITH INTEGRAL SPI

    The SPI spectrometer aboard the International Gamma-Ray Astrophysics Laboratory mission regularly observes the Crab Nebula since 2003. We report on observations distributed over 5.5 years and investigate the variability of the intensity and spectral shape of this remarkable source in the hard X-rays domain up to a few MeV. While single power-law models give a good description in the X-ray domain (mean photon index ∼ 2.05) and MeV domain (photon index ∼ 2.23), crucial information is contained in the evolution of the slope with energy between these two values. This study has been carried out through individual observations and long duration (∼ 400 ks) averaged spectra. The stability of the emission is remarkable and excludes a single power-law model. The slopes measured below and above 100 keV agree perfectly with the last values reported in the X-ray and MeV regions, respectively, but without indication of a localized break point. This suggests a gradual softening in the emission around 100 keV and thus a continuous evolution rather than an actual change in the mechanism parameters. In the MeV region, no significant deviation from the proposed power-law model is visible up to 5-6 MeV. Finally, we take advantage of the spectroscopic capability of the instrument to seek for previously reported spectral features in the covered energy range with negative results for any significant cyclotron or annihilation emission on 400 ks timescales. Beyond the scientific results, the performance and reliability of the SPI instrument is explicitly demonstrated, with some details about the most appropriate analysis method.

  8. Optical excitation function of H(1s-2p) produced by electron impact from threshold to 1.8 keV

    The optical excitation function of prompt Lyman-α radiation, produced by electron impact on atomic hydrogen, has been measured over the extended energy range from threshold to 1.8 keV. Measurements were obtained in a crossed-beams experiment using both magnetically confined and electrostatically focused electrons in collision with atomic hydrogen produced by an intense discharge source. A vacuum-ultraviolet monochromator system was used to measure the emitted Lyman-α radiation. The absolute H(1s-2p) electron impact excitation cross section was obtained from the experimental optical excitation function by normalizing to the accepted optical oscillator strength, with corrections for polarization and cascade. Our data are significantly different from the earlier experimental results and which are limited to energies below 200 eV. Statistical and known systematic uncertainties in our data range from ±4% near threshold to ±2% at 1.8 keV. Multistate coupling affecting the shape of the excitation function up to 1 keV impact energy is apparent in both the present experimental data and present theoretical results obtained with convergent close-coupling (CCC) theory. This shape function effect leads to an uncertainty in absolute cross sections at the 10% level in the analysis of the experimental data. The derived optimized absolute cross sections are within 7% of the CCC calculations over the 14 eV endash 1.8 keV range. The present CCC calculations converge on the Bethe-Fano profile for H(1s-2p) excitation at high energy. For this reason agreement with the CCC values to within 3% is achieved in a nonoptimal normalization of the experimental data to the Bethe-Fano profile. The fundamental H(1s-2p) electron impact cross section is thereby determined to an unprecedented accuracy over the 14 eV endash 1.8 keV energy range. (Abstract Truncated)

  9. Electronic sputtering of solid O{sub 2} by keV Ne ions

    Pedrys, Roman [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Anders, Christian [Fachbereich Physik und Forschungszentrum OPTIMAS, Universität Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern (Germany); Urbassek, Herbert M., E-mail: urbassek@rhrk.uni-kl.de [Fachbereich Physik und Forschungszentrum OPTIMAS, Universität Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern (Germany)

    2015-07-01

    Sputtering of a solid oxygen target is studied both by experiment and by computer simulation. Experimental data of the translational energy distributions of sputtered O{sub 2} molecules are measured for 250 and 750 eV Ne impact; this process is also studied using molecular dynamics computer simulation. Translational energy distributions coincide well for high ejection energies; this proves that the collisional part of the sputtering process is well described by computer simulation. Deviations exist at the low-energy side, below around 0.3 eV; these are assigned to electronic excitations and exothermic chemical reactions that have not been included in the computer model. We show that the sputter contribution from electronic excitation is very similar to that found for 2–9 keV H{sub 2} and H{sub 3} impact and for electron impact at sub-keV energies. Our results thus allow us to separate collisional from electronic sputtering.

  10. Electron stopping power and inelastic mean free path in amino acids and protein over the energy range of 20-20,000 eV.

    Tan, Zhenyu; Xia, Yueyuan; Zhao, Mingwen; Liu, Xiangdong

    2006-07-01

    Systematic calculations of stopping power (SPs) and inelastic mean free path (IMFP) values for 20-20,000 eV electrons in a group of 15 amino acids and a simple protein have been performed. The calculations are based on the dielectric response model and take into account the exchange effect between the incident electron and target electrons. The optical energy-loss functions for the 15 investigated amino acids and the protein are evaluated by using an empirical approach, because of the lack of experimental optical data. For all the considered materials, the calculated mean ionization potentials are in good agreement with those given by Bragg's rule, and the evaluated SP values at 20 keV converge well to the Bethe-Bloch predictions. The data shown represent the first results of SP and IMFP, for these 15 amino acids and the protein in the energy range below 20 keV, and might be useful for studies of various radiation effects in these materials. In addition, the average energy deposited by inelastic scattering of the electrons on this group of 15 amino acids, on the protein, on Formvar and on DNA, respectively, has been estimated for energies below 20 keV. The dependences of the average energy deposition on the electron energy are given. These results are important for any detailed studies of radiation-induced inactivation of proteins and the DNA. PMID:16733724

  11. Contributions to the study of fast neutron spectrum in the 10 keV - 3 MeV range

    The main objective of the work presented in this thesis was to create a fast neutron spectrum corresponding to the conditions required for a reference neutron field. The reference system for the fast neutron dosimetry in reactors, which the author promoted, is referred to as ΣΣ-ITN in the books. The conditions for introducing the ΣΣ systems into the thermal columns have been determined. The original contribution consists in determining the Westcott parameters of reactions 151Eu(n,γ) 152Eu and 176Lu(n,γ) 17+H7Lu used as thermal spectrum factors. The neutron description of the spectrum in cavity ΣΣ revealed that it is a Maxwell thermal spectrum displaying a temperature of 305+-7 deg C and a very small epithermal component (phisub(epi)/phisub(thermal) =4,5.10-4). Better methods for determining reaction absolute rates resulted in less errors in calculating the microscopic integral sections mediated on the ΣΣ spectrum; there are under 5% errors for the fission cross sections and between 3% and 8% errors for the activating ones. The section values determined by the author have been included into the EXFOR library (IAEA); they are considered as reference measuremtns for the nuclear data improvement program. Testing the proposed method for the TRIGA on the ΣΣ-INT system proved that the multiple foil method provides correct results for both describing the spectral shape and for obtaining absolute values of the flux. Taking into account that the ΣΣ-ITN spectrum is a rapid one, the proposed method could not be tested within the low energy thermal and epithermal domain. For testing the method on an operational reactor, the core of the VVR-S IFIN reactor was employed. Due to the spectral structure of this reactor, it was possible to test the procedure within the whole energy range. In this view, the 5/10 core channel was selected which is similar to the channel required for measurements in the TRIGA-ROMANIA reactor. The absolute spectrum values are given in a

  12. Study of natMg(d,d0) reaction at detector angles between 90° and 170°, for the energy range Ed,lab=1660–1990 keV

    In the present work, the study of the natMg(d,d0) is presented for the energy range Ed,lab = 1660–1990 keV (in steps of 5 keV), for detector angles between 90° and 170°. Elastic scattering data for two forward angles (55° and 70°) were also obtained. In order to validate the obtained experimental results a thick Mg sample with Au evaporated on top was fabricated and benchmarking measurements were performed at various deuteron beam energies. The results of the present work are complementary to the recently published 24Mg(d,p0,1,2) reaction cross section data, thus facilitating the simultaneous depth profiling study of magnesium by both the d-NRA and EBS techniques

  13. LAPSI 2.0

    Lundqvist, Björn; Forsberg, Yrsa; de Vries, Marc;

    availability of PSI. In fact, Article 6 of the PSI Directive imposes, as the general rule, marginal cost, as the ceiling, for what fees may be obtained by the Public Sector Bodies (PSBs). Interestingly, lately incumbent market players have been submitting claims that this change of policy is in fact illicit...... governments throughout Europe and in fact frustrate the sound application of the PSI Directive. A possible collision of the PSI Directive and European competition (law) principles – The LAPSI 2.0 Network has adopted it as the subject of a position paper under WP 3 (IP and competition law). The paper will...

  14. Determination of Radiation Shielding for Electron Beam Machine (EBM) 350 keV/20 mA in P3TM-BATAN Yogyakarta

    The radiation shielding determination for electron beam machine 350 keV/20 mA has been studied. When electron beam machine is in operation. the X ray will be produced as the result of interaction between electron beam with materials to be irradiated such as with beam stopper. If the X rays is over than permissible dose it is dangerous to the health and personal safety. Therefore it is necessary to study the ability of radiation shielding to be used in EBM to protect the radiation personnel. The function of radiation shielding is to shield or to reduce X rays which will be accepted by radiation personnel. The radiation shielding of EBM room is constructed with concrete density of 2.35x103 kg/m3 and has thickness of 45 cm and 100 cm. For the permissible dose rate of 2.5 mrem/hour, the thickness of EBM room shielding is satisfied to safety. Otherwise if the permissible dose rate limitation is reduced to 1 mrem/hour, the thickness of EBM room shielding has to be increased especially at western and eastern side by 2.75 cm of thickness respectively. (author)

  15. A novel flat-response x-ray detector in the photon energy range of 0.1-4 keV

    A novel flat-response x-ray detector has been developed for the measurement of radiation flux from a hohlraum. In order to obtain a flat response in the photon energy range of 0.1-4 keV, it is found that both the cathode and the filter of the detector can be made of gold. A further improvement on the compound filter can then largely relax the requirement of the calibration x-ray beam. The calibration of the detector, which is carried out on Beijing Synchrotron Radiation Facility at Institute of High Energy Physics, shows that the detector has a desired flat response in the photon energy range of 0.1-4 keV, with a response flatness smaller than 13%. The detector has been successfully applied in the hohlraum experiment on Shenguang-III prototype laser facility. The radiation temperatures inferred from the detector agree well with those from the diagnostic instrument Dante installed at the same azimuth angle from the hohlraum axis, demonstrating the feasibility of the detector.

  16. Calibration of an UTW Si(Li) detector in the 0.28-22.1 keV energy range

    Uzonyi, I; Borbely-Kiss, I; Kiss, A Z

    2003-01-01

    The application of such detectors in the sub-keV region has been quite limited supposedly due to the lack of well-established calibration methods and the difficulties associated with their operation. The aim of this study has been twofold: first to check the applicability of the (micro)PIXE method for efficiency measurement of an UTW detector in the C K-Ag K subalpha energy region using thick targets, allowing a simple and low-cost solution for this problem; second: to test the new version of the PIXEKLM program down to the sub-keV range. (R.P.)

  17. Influence of the PMMA slab and ISO water phantom in calibrating personal dosimeter in the energy range of 36-662 keV

    Personnel dosimeter calibration for the determination of operational quantities used in individual monitoring requires placement on a phantom that provides a reasonable approximation to the backscatter properties of the part of the body on which it is worn. The personal dose equivalent Hp(d) is defined in the human body which is not a measurable quantity. The reference International Commission on Radiation Units and Measurements (ICRU) tissue is not readily available; hence a phantom of alternative must be used for calibration. The well recognized polymethylmethacrylate (PMMA) slab phantom of size 30x30x15 cm3 are still being used in calibrating personal dosimeters. The International Organization for Standardization (ISO)-4037(3) has proposed another phantom of the same size as ICRU, which is named as ISO water phantom. In the present study, calibrated X-ray fields are characterized for National Institute of Advanced Industrial Science and Technology (AIST) middle beam spectrum series by which the influence of these proposed phantoms has been studied by the thermoluminescence dosimetry (TLD) technique. Discrepancies of responses within 8% have been observed at lower energies up to 42 keV. There is a very good agreement in responses is observed for ISO water slab and PMMA slab phantom for photon energies above 42 keV. Experimentally obtained correction factors for AIST radiation qualities of M50 and M60 for PMMA slab to ISO water phantom is proposed. Measured backscatter factor results from PMMA to ISO water-filled phantoms over the photon energy range 36 to 662 keV are reported. This shows that the new ISO water phantom is a better substitute of ICRU tissue phantom than the PMMA slab. (author)

  18. Simple parametrization of photon mass energy absorption coefficients of H-, C-, N- and O-based samples of biological interest in the energy range 200–1500 keV

    V Manjunathaguru; T K Umesh

    2009-02-01

    In this paper, we provide polynomial coefficients and a semi-empirical relation using which one can derive photon mass energy absorption coefficient of any H-, C-, N-, O-based sample of biological interest containing any other elements in the atomic number range 2–40 and energy range 200–1500 keV. More interestingly, it has been observed in the present work that in this energy range, both the mass attenuation coefficients and the mass energy absorption coefficients for such samples vary only with respect to energy. Hence it was possible to represent the photon interaction properties of such samples by a mean value of these coefficients. By an independent study of the variation of the mean mass attenuation coefficient as well as mass energy absorption coefficient with energy, two simple semi-empirical relations for the photon mass energy absorption coefficients and one relation for the mass attenuation coefficient have been obtained in the energy range 200–1500 keV. It is felt that these semi-empirical relations can be very handy and convenient in biomedical and other applications. One possible significant conclusion based on the results of the present work is that in the energy region 200–1500 keV, the photon interaction characteristics of any H-, C-, N-, O-based sample of biological interest which may or may not contain any other elements in the atomic number range 2–40 can be represented by a sample-independent (single) but energy-dependent mass attenuation coefficient and mass energy absorption coefficient.

  19. Controlling the apex angle of carbon cone induced by 1.2 keV argon ions at room temperature

    Carbon nanofiber-tipped-cones with controllable apex angle were fabricated by sputtering graphite with 1.2keV Ar+ ions in different incident angles at room temperature. The density of carbon cones was estimated at 1 x 109- 1 x 1010/cm2. The cones with carbon nanofiber were oriented to the ion-beam direction. By increasing the incidence from 30 degree to 60 degree, the apex angle of cones decreased from 33 degree to 20 degree, and the aspect ratio increased from 250nm/150nm to 1200nm/400nm. The decreased apex angle, and the increased aspect ratio and density of the cones, were attributed to decreasing effective diffuse coefficient induced by the ion beam and increasing sputtering yield. By increasing the current density from 200 μA/cm2 to 800 μA/cm2, the apex angle of cones decreased from 90 degree to 20 degree and the height of cones increased from 100nm to 1200nm. The increased dose rate caused by larger current densities of the ion beam should result in the different number of the sputtered atom or cluster, which was considered as reason of the decrement of the apex angle and the increment of the height of cones. (authors)

  20. SURVIVAL DEPTH OF ORGANICS IN ICES UNDER LOW-ENERGY ELECTRON RADIATION (≤2 keV)

    Icy surfaces in our solar system are continually modified and sputtered with electrons, ions, and photons from solar wind, cosmic rays, and local magnetospheres in the cases of Jovian and Saturnian satellites. In addition to their prevalence, electrons specifically are expected to be a principal radiolytic agent on these satellites. Among energetic particles (electrons and ions), electrons penetrate by far the deepest into the ice and could cause damage to organic material of possible prebiotic and even biological importance. To determine if organic matter could survive and be detected through remote sensing or in situ explorations on these surfaces, such as water ice-rich Europa, it is important to obtain accurate data quantifying electron-induced chemistry and damage depths of organics at varying incident electron energies. Experiments reported here address the quantification issue at lower electron energies (100 eV-2 keV) through rigorous laboratory data analysis obtained using a novel methodology. A polycyclic aromatic hydrocarbon molecule, pyrene, embedded in amorphous water ice films of controlled thicknesses served as an organic probe. UV-VIS spectroscopic measurements enabled quantitative assessment of organic matter survival depths in water ice. Eight ices of various thicknesses were studied to determine damage depths more accurately. The electron damage depths were found to be linear, approximately 110 nm keV–1, in the tested range which is noticeably higher than predictions by Monte Carlo simulations by up to 100%. We conclude that computational simulations underestimate electron damage depths in the energy region ≤2 keV. If this trend holds at higher electron energies as well, present models utilizing radiation-induced organic chemistry in icy solar system bodies need to be revisited. For interstellar ices of a few micron thicknesses, we conclude that low-energy electrons generated through photoionization processes in the interstellar medium could

  1. Contribution to time resolved X-ray fluence and differential spectra measurement method improvement in 5-200 KeV range. Application to pulsed emission sources

    Two types of sensors have been developed to measure locally the time-resolved fluence and differential energetic spectrum of pulsed X-ray in the energy range 5 to 200 keV. Rise time of these sensors is very short (10 ns) in order to permit time-resolved measurements. Fluence sensors have been developed by putting filters in front of detector in order to make sensor response independent of X-ray energy and proportional to X-ray fluence. The energetic differential spectrum was calculated by way of a method similar to the ROSS method but using filters separated within a pair defining adjacent spectral width. A detailed analysis of uncertainties affecting calculated fluence and spectrum has been done

  2. ART: Surveying the Local Universe at 2-11 keV

    O'Dell, S. L.; Ramsey, B. D.; Adams, M. L.; Brandt, W. N.; Bubarev, M. V.; Hassinger, G.; Pravlinski, M.; Predehl, P.; Romaine, S. E.; Swartz, D. A.; Urry, C. M.; Vikhlinin, A.; Weisskopf, M. C.

    2008-01-01

    The Astronomical Rontgen Telescope (ART) is a medium-energy x-ray telescope system proposed for the Russian-led mission Spectrum Rontgen-Gamma (SRG). Optimized for performance over the 2-11-keV band, ART complements the softer response of the SRG prime instrument-the German eROSITA x-ray telescope system. The anticipated number of ART detections is 50,000-with 1,000 heavily-obscured (N(sub H)> 3x10(exp 23)/sq cm) AGN-in the SRG 4-year all-sky survey, plus a comparable number in deeper wide-field (500 deg(sup 2) total) surveys. ART's surveys will provide a minimally-biased, nearly-complete census of the local Universe in the medium-energy x-ray band (including Fe-K lines), at CCD spectral resolution. During long (approx.100-ks) pointed observations, ART can obtain statistically significant spectral data up to about 15 keY for bright sources and medium-energy x-ray continuum and Fe-K-line spectra of AGN detected with the contemporaneous NuSTAR hard-x-ray mission.

  3. Lifetime and g-factor results for the 13/2- 1985 keV level in 91Nb and the 15/2- 2288 keV level in 91Zr

    Lifetime and g-factor measurements have been made with pulsed beam-γ time-differential techniques using the 89Y(α,2n)91Nb and 88Sr(α,n)91Zr reactions. A mean lifetime tau=14.4+-0.5 nsec and a g-factor of 1.26+-0.04 were obtained for the 13/2- 1985 keV level in 91Nb and tau=41.9+-1.2 nsec and g=0.70+-0.01 were obtained for the 15/2- 2288 keV level in 91Zr. These results are compared to theoretical calculations for (πgsub(9/2))2(πpsub(1/2)) and (πgsub(9/2))(πpsub(1/2))(γdsub(5/2)) configurations in 91Nb and 91Zr, respectively. (Auth.)

  4. Measurement of the 20 and 90keV Resonances in the O18(p,α)N15 Reaction via the Trojan Horse Method

    La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A. M.; Irgaziev, B.; Tribble, R. E.; Banu, A.; Cherubini, S.; Coc, A.; Crucillà, V.; Goldberg, V. Z.; Gulino, M.; Kiss, G. G.; Lamia, L.; Mrazek, J.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Trzaska, W.; Tumino, A.

    2008-10-01

    The O18(p,α)N15 reaction is of primary importance in several astrophysical scenarios, including fluorine nucleosynthesis inside asymptotic giant branch stars as well as oxygen and nitrogen isotopic ratios in meteorite grains. Thus the indirect measurement of the low energy region of the O18(p,α)N15 reaction has been performed to reduce the nuclear uncertainty on theoretical predictions. In particular the strength of the 20 and 90 keV resonances has been deduced and the change in the reaction rate evaluated.

  5. Comparison of simulated and measured spectra from an X-ray tube for the energies between 20 and 35 keV

    Yücel, M.; Emirhan, E.; Bayrak, A.; Ozben, C.S.; Yücel, E. Barlas, E-mail: barlase@itu.edu.tr

    2015-11-01

    Design and production of a simple and low cost X-ray imaging system that can be used for light industrial applications was targeted in the Nuclear Physics Laboratory of Istanbul Technical University. In this study, production, transmission and detection of X-rays were simulated for the proposed imaging device. OX/70-P dental tube was used and X-ray spectra simulated by Geant4 were validated by comparison with X-ray spectra measured between 20 and 35 keV. Relative detection efficiency of the detector was also determined to confirm the physics processes used in the simulations. Various time optimization tools were performed to reduce the simulation time.

  6. A Typology for Web 2.0

    Dalsgaard, Christian; Sorensen, Elsebeth Korsgaard

    2008-01-01

    technologies it covers. The objective of the paper is to develop a typology that can be used to categorize Web 2.0 technologies. Further, the paper will discuss which of these technologies are unique to Web 2.0. Often, Web 2.0 is described by way of different kinds of software; for instance, blogs, wikis...... design of a learning environment: 1) organizing communicative processes and 2) organizing resources. Organizing communicative processes is supported by Web 2.0’s ability to provide a range of communicative tools that can be organized flexibly by students. Web 2.0 provides opportunities for communities...

  7. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 - 25.26 keV photon energy range

    Mohd Yusof, Mohd Fahmi; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

    2015-04-01

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941).

  8. Measurement of X-ray mass attenuation coefficients in biological and geological samples in the energy range of 7–12 keV

    Information about X-ray mass attenuation coefficients in different materials is necessary for accurate X-ray fluorescent analysis. The X-ray mass attenuation coefficients for energy of 7–12 keV were measured in biological (Mussel and Oyster tissues, blood, hair, liver, and Cabbage leaves) and geological (Baikal sludge, soil, and Alaskite granite) samples. The measurements were carried out at the EXAFS Station of Siberian Synchrotron Radiation Center (VEPP-3). Obtained experimental mass attenuation coefficients were compared with theoretical values calculated for some samples. - Highlights: • The X-ray attenuation coefficients were measured in biological and geological samples. • The difference between the attenuation coefficients in biological samples reached 47%. • The liver sample had the smallest attenuation coefficients. • The theoretical values for liver sample differ from the experimental ones by 2%

  9. Web 2.0 aplikace

    Lednický, Miroslav

    2008-01-01

    Following pages will be about abounded term "Web 2.0". I will try to explain the core characteristics of "Web 2.0" applications. This explanation will be followed by some existing examples of these applications. Main target is to explain the term "Web 2.0".

  10. Measurement of mass attenuation coefficients for four mixtures using X-rays from 13 keV up to 40 keV

    Angelone, M.; Esposito, A.; Chiti, M.; Gentile, A.

    2001-06-01

    The total absorption coefficients for some selected organic compounds relevant to health physics, Triaflol BN (C 3H 4O 2) n, Triaflol TN (C 12H 18O 7) n, Kapton (C 44H 20O 10) n, and Melinex (C 10H 8N 4O 4) n were measured in the X-ray energy range from 13 keV up to about 40 keV using a collimator, high purity germanium detector with thin Be window and variable energy X-ray source. The measured values are compared with the theoretical ones obtained using the XCOM code. The agreement is generally good within a few percent.

  11. Measurement of mass attenuation coefficients for four mixtures using X-rays from 13 keV up to 40 keV

    The total absorption coefficients for some selected organic compounds relevant to health physics, Triaflol BN (C3H4O2)n, Triaflol TN (C12H18O7)n, Kapton (C44H20O10)n, and Melinex (C10H8N4O4)n were measured in the X-ray energy range from 13 keV up to about 40 keV using a collimator, high purity germanium detector with thin Be window and variable energy X-ray source. The measured values are compared with the theoretical ones obtained using the XCOM code. The agreement is generally good within a few percent. (author)

  12. Measurement of mass attenuation coefficients of Eremurus–Rhizophora spp. particleboards for X-ray in the 16.63–25.30 keV energy range

    The roots of Eremurus spp. were used as a bio-adhesive in the fabrication of Rhizophora spp. particleboards. The mass attenuation coefficients of Eremurus–Rhizophora spp. particleboard of six samples with two different weight percentages of the Eremurus spp. root (6% and 12%) and three various Rhizophora spp. particle sizes (≤149 µm, 149–500 µm and 500–1000 µm) were determined by using X-ray fluorescence (XRF) photons in 16.63 keV and 25.30 keV of the photon energy range. The results were compared with theoretically calculated mass attenuations using the XCOM computer program for younger-age (breast 1: 75% muscle+25% fat), middle-age (breast 2: 50% muscle+50% fat), and old-age (breast 3: 25% muscle+75% fat) breasts. The results indicated that Eremurus–Rhizophora spp. particleboard is the appropriate suitable phantom in the diagnostic energy region. The mass attenuation coefficient in the low weight percentage of the bio-adhesive and the large Rhizophora spp. particle size were found very close to breast 1. Moreover the mass attenuation coefficient of the sample with high weight percentage of the bio-adhesive and small Rhizophora spp. particle size was found very close to water as a standard material phantom. In addition, the viscosity of dissolved Eremurus spp. root in water could be considerably higher than that of formaldehyde-based adhesives, which affects on some properties such as high strength and high binding. - Highlights: • Rhizophora spp. particleboard bonded with Eremurus spp. root as a new phantom. • Mass attenuation coefficient of particleboard was measured in 16.63–25.30 keV range. • Mass attenuation coefficient particleboard was affected by particle size and %glue. • Mass attenuation coefficient of particleboard was close to water and young breast. • Viscosity of Eremurus was significantly higher than those of synthetic adhesives

  13. Optical excitation function of H(1s-2p) produced by electron impact from threshold to 1.8 keV

    James, G.K. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Slevin, J.A. [Department of Experimental Physics, St. Patricks College, Maynooth, County Kildare (Ireland); Shemansky, D.E. [Department of Aerospace Engineering, University of Southern California, Los Angeles, California 90089 (United States); McConkey, J.W. [Department of Physics, University of Windsor, Windsor, Ontario, N9B3P4 (CANADA); Bray, I. [Electronic Structure of Materials Centre, The Flinders University of South Australia, G.P.O. Box 2100, Adelaide 5001 (Australia); Dziczek, D. [Institute of Physics, Nicholas Copernicus University, 87-100 Torun (Poland); Kanik, I.; Ajello, J.M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    1997-02-01

    The optical excitation function of prompt Lyman-{alpha} radiation, produced by electron impact on atomic hydrogen, has been measured over the extended energy range from threshold to 1.8 keV. Measurements were obtained in a crossed-beams experiment using both magnetically confined and electrostatically focused electrons in collision with atomic hydrogen produced by an intense discharge source. A vacuum-ultraviolet monochromator system was used to measure the emitted Lyman-{alpha} radiation. The absolute H(1s-2p) electron impact excitation cross section was obtained from the experimental optical excitation function by normalizing to the accepted optical oscillator strength, with corrections for polarization and cascade. Our data are significantly different from the earlier experimental results and which are limited to energies below 200 eV. Statistical and known systematic uncertainties in our data range from {plus_minus}4{percent} near threshold to {plus_minus}2{percent} at 1.8 keV. Multistate coupling affecting the shape of the excitation function up to 1 keV impact energy is apparent in both the present experimental data and present theoretical results obtained with convergent close-coupling (CCC) theory. This shape function effect leads to an uncertainty in absolute cross sections at the 10{percent} level in the analysis of the experimental data. The derived optimized absolute cross sections are within 7{percent} of the CCC calculations over the 14 eV{endash}1.8 keV range. The present CCC calculations converge on the Bethe-Fano profile for H(1s-2p) excitation at high energy. For this reason agreement with the CCC values to within 3{percent} is achieved in a nonoptimal normalization of the experimental data to the Bethe-Fano profile. The fundamental H(1s-2p) electron impact cross section is thereby determined to an unprecedented accuracy over the 14 eV {endash} 1.8 keV energy range. (Abstract Truncated)

  14. Recent capture cross section data from ORELA above 2.6 keV

    Neutron capture by natural rhodium (103Rh) and enriched stable isotopes of ruthenium (100 to 104) and palladium (104 to 110) were measured at the Oak Ridge Electron Linear Accelerator pulsed neutron facility. Average pure isotope cross sections from three to several hundred keV were derived. The neutron flux shape was determined relative to ENDF/B V standard 6Li(n,α) and 235U(n,f) cross sections below and above 70 keV respectively. Strength functions were adjusted to fit the data by least squares. The 101Ru fission product would appear to cause less poisoning than 105Pd or 103Rh in plutonium fueled fast reactors. 7 references

  15. Recent capture cross section data from ORELA above 2.6 keV

    Neutron capture by natural rhodium (103Rh) and enriched stable isotopes of ruthenium (100 to 104) and palladium (104 to 110) were measured at the Oak Ridge Electron Linear Accelerator pulsed neutron facility. Average pure isotope cross sections from three to several hundred keV were derived. The neutron flux shape was determined relative to ENDF/B V standard 6Li(n,α) and 235U(n,f) cross sections below and above 70 keV respectively. Strength functions were adjusted to fit the data by least squares. The 101Ru fission product would appear to cause less poisoning than 105Pd or 103Rh in plutonium fueled fast reactors

  16. Developing a Compton Polarimeter to Measure Polarization of Hard X-Rays in the 50-300 keV Energy Range

    Legere, J S; Macri, J R; McConnell, M L; Narita, T; Ryan, J M

    2005-01-01

    This paper discusses the latest progress in the development of GRAPE (Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs). Accurately measuring the polarization of the emitted radiation from these sources will lead, to a better understating of both the emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. We can monitor individual Compton scatters that occur in the plastics and determine whether the photon is photo absorbed by the high-Z crystal or not. A Compton scattered photon that is immediately photo absorbed by the high-Z crystal constitutes a valid event. These valid events provide us with the interaction locations of each incident photon and ultimately produces a modulation pattern fo...

  17. High accuracy measurement of the $^{235}$U(n,f) reaction cross-section in the 10-30 keV neutron energy range

    The analysis of the neutron flux of n_TOF (in EAR1) revealed an anomaly in the 10-30 keV neutron energy range. While the flux extracted on the basis of the $^{6}$Li(n,t)$^{4}$He and $^{10}$B(n,$\\alpha$)$^{7}$Li reactions mostly agreed with each other and with the results of FLUKA simulations of the neutron beam, the one based on the $^{235}$U(n,f) reaction was found to be systematically lower, independently of the detection system used. A possible explanation is that the $^{235}$U(n,f) crosssection in that energy region, where in principle should be known with an uncertainty of 1%, may be systematically overestimated. Such a finding, which has a negligible influence on thermal reactors, would be important for future fast critical or subcritical reactors. Furthermore, its interest is more general, since the $^{235}$U(n,f) reaction is often used at that energy to determine the neutron flux, or as reference in measurements of fission cross section of other actinides. We propose to perform a high-accuracy, high-r...

  18. Time-resolved analysis of the X-ray emission of femtosecond-laser-produced plasmas in the 1.5-keV range

    Bastiani-Ceccotti, S.; Audebert, P.; Nagels-Silvert, V.; Geindre, J. P.; Gauthier, J. C.; Adam, J. C.; Héron, A.; Chenais-Popovics, C.

    Recent experimental results on ion beams produced in high-intensity laser-solid interactions indicate the presence of very intense electric fields in the target. This suggests the possibility of efficiently heating a solid material by means of the fast electrons created during the laser-solid interactions and trapped in the target, rather than by the laser photons themselves. We tested this mechanism by irradiating very small cubic aluminum targets with the LULI 100-TW, 300-fs laser at 1.06-μm wavelength. X-ray spectra were measured with an ultra-fast streak camera, coupled to a conical Bragg crystal, providing spectra in the 1.5-keV range with high temporal and spectral resolution. The results indicate the creation of a hot plasma, but a very low coupling between the rapid electrons and the solid. A tentative explanation, in agreement with other experimental results and with preliminary particle-in-cell (PIC) simulations, points out the fatal role of the laser prepulse.

  19. Measurement of U-235 absolute alpha value in the neutron energy range from 0.1 to 30 keV

    In order to measure the neutron-physical constants with high accuracy and to investigate ways of formation and decay of excited nuclei a method has been developed at the I.V. Kurchatov AEI, based on the gamma-quanta and neutrons multiplicity spectrometry. During 1974-1978 there have been constructed a number of multisectional 4π-detectors which have demonstrated great possibilities for this method. A detector permitting the required accuracy of measurements of neutron cross sections and their ratios has been chosen and designed on the basis of these works. The detector with 4π-geometry has 46 sections and was based on naI(Tl) crystals with the total volume of the scintillator of approx. 100 1. The detector was used at the 26-m station. The results of U-235 absolute alpha value measurements are presented. The measurements are carried out over the energy range from 0.1 to 30 keV with the high accuracy - better than 5%. The equipment parameters and measurement conditions are listed

  20. Web 2.0

    胡泳

    2007-01-01

    Web 2.0是现在媒体上常见的名词,但究竟什么是Web 2.0?这个术语的始作俑者蒂姆·欧内利是这样定义的:“Web 2.0指网络作为平台,横跨所有互联设备;Web 2.0应用充分调动这一平台的内在优势:把软件作为不断升级的服务加以提供,使用软件的人越多,软件变得越好;这些应用从多种来源(包括个人用户)吸取和重混数据,与此同时,允许自己的数据和服务被他人重混。”这个定义由于技术化而显得晦涩难解。在另一处,欧内利举例

  1. Development of a flat-field spectrograph with a wide-band multilayer grating and prefocusing mirror covering 2-4 keV

    A flat-field spectrograph equipped with a wide-band multilayer grating and prefocusing mirror covering 2–4 keV without any mechanical movement has been developed. To realize this, a new multilayer structure consisting of W and B4C layers has been invented, which enhances the diffraction efficiency of the grating over the whole energy range at a fixed angle of incidence as well as the reflectivity of the prefocusing mirror. The multilayer has been deposited on a laminar-type varied-line-spacing holographic replica grating and a spherical mirror substrate. The diffraction efficiency of the multilayer grating varies between 1.2% and 3.3% at 88.65° in the 2.1–4.0 keV range. Also the reflectivity of the prefocusing mirror varies between 2.7% and 12% at 88.00° in the same range. The overall throughput of the spectrograph with the multilayer optics is 104 times higher than that of gold-coated optics.

  2. High resolution measurement of the 234U(n,f) cross section in the neutron energy range from 0.5 eV to 100 keV

    The 234U(n,f) cross section has been measured in the energy range from 0.5 eV to 100 keV at the GELINA neutron time-of flight facility of the Institute for Reference Materials and Measurements in Geel using highly enriched 234U samples. Two independent measurements were performed: one in a low detection geometry (15% of 2 π) and another in a 2 π detection geometry. A235U(n,f) cross-section measurement was performed under the same experimental conditions, allowing a reliable correction for the 235U(n,f) contribution to the yield. Special attention has been given to the strongest resonance at 5.16 eV and to the fission resonance integral If for which large discrepancies are reported in the literature. (authors)

  3. Dependence of spectral shape of bremsstrahlung spectra on atomic number of target materials in the photon energy range of 5-30 keV

    Dependence of spectral shape of total bremsstrahlung spectra i.e. the sum of ordinary bremsstrahlung (OB) and polarization bremsstrahlung (PB), on the atomic number (Z) of target materials (Al, Ti, Sn and Pb), produced by continuous beta particles of 90Sr and 204Tl, has been investigated in the photon energy region of 5-30 keV. It has been found that the spectral shape of total bremsstrahlung spectra, in terms of S (k, Z) i.e. the number of photons of energy k per moc2 per beta disintegration, is not linearly dependent on the atomic number (Z) of the target material and rather it is proportional to Zn. At lower photon energies, the index values ‘n’ of Z-dependence are much higher than unity, which is due to the larger contribution of PB into OB. The decrease in ‘n’ values with increase of photon energy is due to the decrease in contribution of PB into OB. It is clear that the index ‘n’ values obtained from the modified Elwert factor (relativistic) Bethe-Heitler theory, which include the contribution PB into OB, are in agreement with the experimentally measured results using X-PIPS Si(Li) detector. Hence the contribution of PB into the formation of a spectral shape of total bremsstrahlung spectra plays a vital role.

  4. Developing a Compton polarimeter to measure polarization of hard x-rays in the 50-300 keV energy range

    Legere, Jason; Bloser, Peter L.; Macri, John R.; McConnell, Mark L.; Narita, Tomohiko; Ryan, James M.

    2005-08-01

    This paper discusses the latest progress in the development of GRAPE (Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs). Accurately measuring the polarization of the emitted radiation from these sources will lead, to a better understating of both the emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. We can monitor individual Compton scatters that occur in the plastics and determine whether the photon is photo absorbed by the high-Z crystal or not. A Compton scattered photon that is immediately photo absorbed by the high-Z crystal constitutes a valid event. These valid events provide us with the interaction locations of each incident photon and ultimately produces a modulation pattern for the Compton scattering of the polarized radiation. Comparing with Monte Carlo simulations of a 100% polarized beam, the level of polarization of the measured beam can then be determined. The complete array is mounted on a flat-panel multi-anode photomultiplier tube (MAPMT) that can measure the deposited energies resulting from the photon interactions. The design of the detector allows for a large field-of-view, at the same time offering the ability to be close-packed with multiple modules in order to reduce deadspace. We plan to present in this paper the latest laboratory results obtained from GRAPE using partially polarized radiation sources.

  5. Improved energies for the 5.2 keV M1 and 42.0 keV M2 nuclear transitions in Rb-83

    Inoyatov, A. K.; Ryšavý, Miloš; Kovalík, Alojz; Filosofov, D. V.; Zhdanov, V. S.; Yushkevich, Yu. V.

    2014-01-01

    Roč. 50, č. 3 (2014), s. 1-6. ISSN 1434-6001 R&D Projects: GA ČR(CZ) GAP203/12/1896; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : internal-conversion * decay Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 2.736, year: 2014

  6. Spectroscopic monitoring of gamma-rays of Earth and space origin in the 150-6400 KeV range at Moussala BEO

    A gamma-spectrometer with a NaI detector and a suitable lead collimator directed to the sky was put in operation at Moussala BEO at an altitude of 2925 m above sea level. The gamma-rays spectrum in the 150–6500 keV energy interval was measured at two-hour intervals. In many cases, significant fluctuations were observed in the 222Rn lines intensity. Fluctuations of the gamma-rays intensity in the 2800–6400 keV energy interval were also observed. These gamma-rays originate from the interaction of various cosmic rays with Earth’s atmosphere. The device’s stability was controlled through the intensity of the 1460 keV gamma-line of the 40K background. Key words: Moussala, gamma-rays, NaI, detector, fluctuations, atmosphere

  7. Bolometer characterisation with a specially developed cryogenic source having more than five peaks in the 1-6 keV range

    A very low temperature (10-50 mK), and at relatively low energy (typically 100 eV-10 keV), the linearity and resolution of bolometers need to be carefully tested. Commercially available sources below 6 keV are rate and difficult to cool down. We have developed a specially designed compact X-ray source where 55Fe is combined with an ion-exchange membrane containing more than three fluorescent elements. More than five peaks can be identified form 1 keV to 6.5 keV. A spectrum obtained with a 0.5 mg composite diamond bolometer, allowing a good measurement of linearity and resolution as a function of energy is presented. It is compared with a spectrum of the same source measured with a classical germanium detector. Since bolometer detectors have neither window, nor dead layer effects. Bolometer spectra obtained with these sources could be used to directly calibrate the efficiency response of classical detectors at very low energy. (orig.)

  8. Correlation between electrical transport, microstructure and room temperature ferromagnetism in 200 keV Ni{sup 2+} ion implanted zinc oxide (ZnO) thin films

    Joshi, B. [Gautam Buddha University, Department of Applied Sciences, Greater Noida (India); Ghosh, S.; Srivastava, P. [Indian Institute of Technology Delhi, Nanostech Laboratory, New Delhi (India); Kumar, P.; Kanjilal, D. [Aruna Asaf Ali Marg, Inter University Accelerator Centre, New Delhi (India)

    2012-05-15

    We report variable temperature resistivity measurements and mechanisms related to electrical conduction in 200 keV Ni{sup 2+} ion implanted ZnO thin films deposited by vapor phase transport. The dc electrical resistivity versus temperature curves show that all polycrystalline ZnO films are semiconducting in nature. In the room temperature range they exhibit band conduction and conduction due to thermionic emission of electrons from grain boundaries present in the polycrystalline films. In the low temperature range, nearest neighbor hopping (NNH) and variable range hopping (VRH) conduction are observed. The detailed conduction mechanism of these films and the effects of grain boundary (GB) barriers on the electrical conduction process are discussed. An attempt is made to correlate electrical conduction behavior and previously observed room temperature ferromagnetism of these films. (orig.)

  9. kev neutron capture in zirconium-91

    The neutron capture cross section of 91Zr has been measured with high resolution (ΔE/E approximately 0.2 per cent) between 3 and 30 keV. Values of the gGAMMAsub(n)GAMMAsub(γ) for 119 resonances in this energy range have been obtained. The average capture cross section is consistent with values of = = 200. (author)

  10. Revisiting the relationship between 6 {\\mu}m and 2-10 keV continuum luminosities of AGN

    Mateos, S; Carrera, F. J.; Alonso-Herrero, A.; Rovilos, E.; Hernán-Caballero, A.; Barcons, X.; Blain, A.; Caccianiga, A.; R. Della Ceca(INAF, Oss. di Brera); Severgnini, P.

    2015-01-01

    We have determined the relation between the AGN luminosities at rest-frame 6 {\\mu}m associated to the dusty torus emission and at 2-10 keV energies using a complete, X-ray flux limited sample of 232 AGN drawn from the Bright Ultra-hard XMM-Newton Survey. The objects have intrinsic X-ray luminosities between 10^42 and 10^46 erg/s and redshifts from 0.05 to 2.8. The rest-frame 6 {\\mu}m luminosities were computed using data from the Wide-Field Infrared Survey Explorer and are based on a spectral...

  11. Stopping power and mean free path for low-energy electrons in ten scintillators over energy range of 2020,000 eV

    Systematic calculations of the stopping powers (SP) and inelastic mean free paths (IMFP) for 2020,000 eV electrons in a group of 10 important scintillators have been carried out. The calculations are based on the dielectric model including the Born–Ochkur exchange correction and the optical energy loss functions (OELFs) are empirically evaluated because of the lack of available experimental optical data for the scintillators under consideration. The evaluated OELFs are examined by both the f-sum rule and the calculation of mean ionization potential. The SP and IMFP data presented here are the first results for the 10 scintillators over the energy range of 2020,000 eV, and are of key importance for the investigation of liquid scintillation counting. - Highlights: ► Scintillators are important materials used in liquid scintillation counting (LSC). ► Stopping power (SP) and inelastic mean free path (IMFP) are important for LSC. ► SPs and IMFPs for electrons of 20 eV–20 keV in 10 scintillators systematically calculated. ► Dielectric model used and optical energy loss function empirically evaluated. ► SP and IMFP data presented here are the first results for the 10 scintillators.

  12. Efficiency calibration for HPGe detector using different sample densities and different volumes in the energy range 63.3 and 2614.7 keV

    Different density samples were chosen to find the relation between the sample density and the detector efficiency. All samples selected were mixed with a known weight of monazite material which contains known concentrations of 238U and 232Th. These samples are bran, water, soil and sand which have densities of 0.4513, 1.0, 1.322 and 1.869 g/cm3 respectively. Five gamma ray energie lines were selected for this study these are 92.6 keV of 234Th (U-series), 129.1 and 911.1 keV of 228Ac and 583.1 and 2614.7 keV of 208 Tl (Th-series). The obtained results showed that there are exponential decay relations between sample densities and the detector efficiency at all gamma ray energie lines selected. Also the relation between sample densities and the absolute efficiency of the detector used was studied at the same gamma-ray energy lines and the same results were obtained. The variation of absolute efficiency of the detector according to the densities was attributed mainly to the effect of the mass absorption coefficient of the different materials

  13. Measurement of the x-ray mass attenuation coefficient and determination of the imaginary component of the atomic form factor of molybdenum over the 13.5-41.5-keV energy range

    We use the x-ray extended-range technique (XERT) [Chantler et al., Phys. Rev. A 64, 062506 (2001)] to measure the mass attenuation coefficients of molybdenum in the x-ray energy range of 13.5-41.5 keV to 0.02-0.15 % accuracy. Measurements made over an extended range of the measurement parameter space are critically examined to identify, quantify, and correct where necessary a number of experimental systematic errors. These results represent the most extensive experimental data set for molybdenum and include absolute mass attenuation coefficients in the regions of the x-ray absorption fine structure (XAFS) and x-ray-absorption near-edge structure (XANES). The imaginary component of the atomic form-factor f2 is derived from the photoelectric absorption after subtracting calculated Rayleigh and Compton scattering cross sections from the total attenuation. Comparison of the result with tabulations of calculated photoelectric absorption coefficients indicates that differences of 1-15 % persist between the calculated and observed values

  14. Revisiting the relationship between 6 {\\mu}m and 2-10 keV continuum luminosities of AGN

    Mateos, S; Alonso-Herrero, A; Rovilos, E; Hernán-Caballero, A; Barcons, X; Blain, A; Caccianiga, A; Della Ceca, R; Severgnini, P

    2015-01-01

    We have determined the relation between the AGN luminosities at rest-frame 6 {\\mu}m associated to the dusty torus emission and at 2-10 keV energies using a complete, X-ray flux limited sample of 232 AGN drawn from the Bright Ultra-hard XMM-Newton Survey. The objects have X-ray luminosities corrected for intrinsic absorption between 10^42 and 10^46 erg/s and redshifts from 0.05 to 2.8. The rest-frame 6 {\\mu}m luminosities were computed using data from the Wide-Field Infrared Survey Explorer and are based on a spectral energy distribution decomposition into AGN and galaxy emission. The best-fit relationship for the full sample is consistent with being linear, L_6 {\\mu}m $\\propto$ L_2-10 keV^0.99$\\pm$0.032, but has significant intrinsic scatter, ~0.35 dex in log L_6 {\\mu}m. Assuming a constant X-ray bolometric correction, the fraction of AGN bolometric luminosity reprocessed in the mid-IR decreases weakly, if at all, with the AGN luminosity, a finding at odds with simple receding torus models. Type 2 AGN have re...

  15. Air kerma to personal dose equivalent conversion factors for ICRU and ISO recommended slab phantoms for photons from 20 keV to 1 MeV

    The present report summarizes the studies carried out at ENEA-AMB-PRO-IRP (Institute for Radiation Protection) that were addressed to the determination of air kerma to personal dose equivalent conversion coefficients for two practical phantoms as proposed by ICRU (International Commission for Radiation Units and Measurements) and by ISO (International Standard Organization) for photon personal dosimeters' calibration procedure. The analyses, developed using the MCNP Monte Carlo code, were mainly aimed at establishing which of the two proposed phantoms better approximates the ICRU theoretical one. Furthermore a complete tabulation of the conversion coefficients is supplied for monoenergetic photon beams from 20 keV to 1 MeV as well as for the two ISO X-ray reference series Wide Spectrum and Narrow Spectrum. The study has been performed in the framework of the CEC Contract F13P-CT92-0064 'The Measurement of the Spectral and Angular Distribution of External Radiations in Workplace and Implications for Personal Dosimetry

  16. INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth

    Churazov, E.; Sunyaev, R.; Revnivtsev, M.;

    2007-01-01

    due to occultation of extragalactic objects by the Earth disk was used to obtain the spectrum of the Cosmic X-ray Background ( CXB). Various sources of contamination were evaluated, including compact sources, Galactic Ridge emission, CXB reflection by the Earth atmosphere, cosmic ray induced emission...... by the Earth atmosphere and the Earth auroral emission. Results. The spectrum of the cosmic X-ray background in the energy band 5-100 keV is obtained. The shape of the spectrum is consistent with that obtained previously by the HEAO-1 observatory, while the normalization is similar to 10% higher...

  17. Fine pitch CdTe-based Hard-X-ray polarimeter performance for space science in the 70-300 keV energy range

    Antier, S; Ferrando, P

    2015-01-01

    X-rays astrophysical sources have been almost exclusively characterized through imaging, spectroscopy and timing analysis. Nevertheless, more observational parameters are needed because some radiation mechanisms present in neutrons stars or black holes are still unclear. Polarization measurements will play a key role in discrimination between different X-ray emission models. Such a capability becomes a mandatory requirement for the next generation of high-energy space proposals. We have developed a CdTe-based fine-pitch imaging spectrometer, Caliste, able to respond to these new requirements. With a 580-micron pitch and 1 keV energy resolution at 60 keV, we are able to accurately reconstruct the polarization angle and polarization fraction of an impinging flux of photons which are scattered by 90{\\deg} after Compton diffusion within the crystal. Thanks to its high performance in both imaging and spectrometry, Caliste turns out to be a powerful device for high-energy polarimetry. In this paper, we present the ...

  18. Linear and mass attenuation coefficient for CdTe compound of X-rays from 10 to 100 keV energy range in different phases

    The Full Potential Linear Muffin Tin Orbitals method within the density functional theory has been utilized to calculate structural and electronic properties of the CdTe compound. We have checked that the CdTe has two phase-transitions from zinc-blend to cinnabar and from cinnabar to rocksalt. We have found that the rigidity, the energy and the nature of the gap change according to the phase change, so we can predict that a CdTe detector may have different behaviors in different phase conditions. In order to investigate this behavior change, the linear and the mass attenuation coefficients of X-ray in rocksalt, zinc-blend and cinnabar structures are calculated from 10 keV to100 keV, using the XCOM data. We have found that when CdTe undergoes a phase transition from zinc-blend to cinnabar, its linear attenuation coefficient decreases down to a value of about 100 times smaller than its initial one, and when it undergoes a transition from cinnabar to rocksalt it increases up to a value about 90 times larger than its initial one

  19. Linear and mass attenuation coefficient for CdTe compound of X-rays from 10 to 100 keV energy range in different phases

    Saim, A., E-mail: saim1989asma@gmail.com; Tebboune, A.; Berkok, H.; Belameiri, N.; Belbachir, A.H.

    2014-07-25

    The Full Potential Linear Muffin Tin Orbitals method within the density functional theory has been utilized to calculate structural and electronic properties of the CdTe compound. We have checked that the CdTe has two phase-transitions from zinc-blend to cinnabar and from cinnabar to rocksalt. We have found that the rigidity, the energy and the nature of the gap change according to the phase change, so we can predict that a CdTe detector may have different behaviors in different phase conditions. In order to investigate this behavior change, the linear and the mass attenuation coefficients of X-ray in rocksalt, zinc-blend and cinnabar structures are calculated from 10 keV to100 keV, using the XCOM data. We have found that when CdTe undergoes a phase transition from zinc-blend to cinnabar, its linear attenuation coefficient decreases down to a value of about 100 times smaller than its initial one, and when it undergoes a transition from cinnabar to rocksalt it increases up to a value about 90 times larger than its initial one.

  20. Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

    The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data

  1. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20 to 250 MeV

    Mclean, Thomas D [Los Alamos National Laboratory; Justus, Alan L [Los Alamos National Laboratory; Gadd, S Milan [Los Alamos National Laboratory; Olsher, Richard H [RP-2; Devine, Robert T [RP-2

    2009-01-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

  2. Resonance neutron capture by manganese below 2.5 keV

    Radiation widths GAMMA /sub gamma/ of (310 + or - 20), (312 + or - 12), and (340 + or - 130) MeV were found for 55Mn(n,√) resonances at 337, 109, and 2327 eV, respectively. A fourth resonance was found at 1658 eV, with gGAMMA /sub n/ GAMMA /sub mk/ / GAMMA = (7.6 + or - 0.3) MeV

  3. Dense ion clouds of 0.1 − 2 keV ions inside the CPS-region observed by Astrid-2

    O. Norberg

    Full Text Available Data from the Astrid-2 satellite taken between April and July 1999 show several examples of dense ion clouds in the 0.1–2 keV energy range inside the inner mag-netosphere, both in the northern and southern hemispheres. These inner magnetospheric ion clouds are found predomi-nantly in the early morning sector, suggesting that they could have originated from substorm-related ion injections on the night side. However, their location and density show no cor-relation with Kp, and their energy-latitude dispersion is not easily reproduced by a simple particle drift model. There-fore, these ion clouds are not necessarily caused by substorm-related ion injections. Alternative explanations for the ion clouds are the direct solar wind injections and up-welling ions from the other hemisphere. These explanations do not, however, account for all of the observations.Key words. Magnetospheric physics (energetic particles, trapped; magnetospheric configuration and dynamics; storm and substorms

  4. Calculations of electron stopping powers for 41 elemental solids over the 50 eV to 30 keV range with the full Penn algorithm

    We present mass collision electron stopping powers (SPs) for 41 elemental solids (Li, Be, graphite, diamond, glassy C, Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Fe, Co, Ni, Cu, Ge, Y, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Cs, Gd, Tb, Dy, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Bi) that were calculated from experimental energy-loss-function data with the full Penn algorithm for electron energies between 50 eV and 30 keV. Improved sets of energy-loss functions were used for 19 solids. Comparisons were made of these SPs with SPs calculated with the single-pole approximation, previous SP calculations, and experimental SPs. Generally satisfactory agreement was found with SPs from the single-pole approximation for energies above 100 eV, with other calculated SPs, and with measured SPs.

  5. Electron transport simulation in the range 1 keV-4 MeV for the purpose of high-resolution dosimetric application

    Cobut, V. [Univ. de Cergy-Pontoise, Neuville/Oise (France). Lab. Pharmacophores Redox, Phytochimie et Radiobiologie; Cirioni, L.; Patau, J.P. [Univ. Paul Sabatier, Toulouse (France). Faculte de Pharmacie

    2001-07-01

    Experimental spectrometry and dosimetry can offer some reliable answers. However, they are not easy to implement in some specific situations. Furthermore, information on dose distributions cannot always be obtained with the desirable geometrical resolution. A way to get rid of these disadvantages consist in simulating every successive individual interactions suffered by electrons and photons along their path. We applied this principle to simulate the response of a detector placed in the field of beta-gamma sources, which maximum energy does not exceed 4 MeV. A part of this work is presented here, which concerns Monte Carlo simulation of electron transport in materials encountered in experimental dosimetric devices. Electrons were followed down to a cutoff energy of 1 keV. (orig.)

  6. Guiding of 60 keV O6+ Ions through Nanocapillaries in an Uncoated Al2O3 Membrane

    CHEN Xi-Meng; YIN Yong-Zhi; LOU Feng-Jun; WANG Xing-An; XU Jun-Kui; ZHOU Chun-Lin; XI Fa-Yuan; QIU Xi-Yu; SHAO Jian-Xiong; CUI Ying; SUN Guang-Zhi; WANG Jun; CHEN Yi-Feng; LIU Hui-Ping

    2008-01-01

    @@ We measure the transmission of O6+ ions with a higher energy of 6O keV (in turna higher value of Ep/q) through capillaries in an uncoated Al2O3 membrane, and obtain agreements with previously reported results in general angular distribution of the transmitted ions and the transmission profile width variation with capillary tilt angle.The transmission fractions as a function of the tilt angle can be fitted to the semi-empirical Gaussian-like function well. Due to using uncoated capillary membrane, our ψc is larger than that using gold-coated one, in spite of our larger value of Ep/q, which suggests a larger equilibrium charge Q∞ in our experiment.

  7. Angular and velocity distributions of the HD sup + and D sub 2 sup + fragments from HD sub 2 sup + colliding with He at energies of 1 to 5 keV

    Alvarez, I.; Martriaanez, H.; Cisneros, C.; de Urquijo, J. (Instituto de Fisica, Universidad Nacional Autonoma de Mexico, P.O. Box 139-B, 62191 Cuernavaca Morelos (Mexico))

    1992-01-01

    The angular and velocity distributions of the HD{sup +} and D{sub 2}{sup +} fragments resulting from collision-induced dissociation of the HD{sub 2}{sup +} molecular ion incident on He have been measured in the energy range 1--5 keV. These distributions were used to determine the binding energy of HD{sub 2}{sup +}, some of the main transitions involved in the dissociation process, and the total cross sections for the production of both fragments.

  8. Development of an X-ray imaging system within 10-30 keV spectral range based on organic or inorganic scintillator

    This thesis aims at developing an x-ray imaging system intended for the Laser Mega Joule, within the framework of Inertial Confinement Fusion (ICF) experiments. ICF aims at yielding thermonuclear energy through laser-driven fusion of a deuterium-tritium mix. The operational function of our system is to acquire an image of the 10-30 keV x-rays emitted by the maximally compressed micro-balloon, with spatial resolution better than 10 μm. The presented system is only a part of a complete diagnostic system, which normally includes an x-ray optical subsystem. Our system conception largely takes vulnerability into account. The ignition phase of ICF yields 1016 neutrons, with energies scaling up to 14 MeV. The neutrons generate such a hard surrounding with effects scaling down from image degradation up to instrumentation destruction. The presented system consists in a scintillator which is focused on a CCD camera through a catadioptric image transport system. An innovation work has been lead on scintillators to provide an answer to specifications greatly influenced by vulnerability. Those thesis works lead to an imaging system allowing to deport the CCD camera by 4 meters from the scintillator, with 100 μm spatial resolution in the scintillator plane. Those works have paved the way to outlooks such as enhancement of organic loaded scintillators compositions and improvement of optical relay system. (author)

  9. Electron Flux Models at GEO: 30 keV - 600 keV

    Boynton, R.; Balikhin, M. A.; Sibeck, D. G.; Walker, S. N.; Ganushkina, N. Y.

    2015-12-01

    Forecast models are developed for the electron fluxes measured by the Magnetospheric Electron Detector (MagED) onboard the Geostationary Operational Environmental Satellite (GOES) 13. The models employ solar wind and geomagnetic indices as inputs to produce a forecast of the electron flux at Geostationary Earth Orbit (GEO) for five energy ranges from 30 keV - 600 keV. All of these models will be implemented in real time to forecast the electron fluxes on the PROGRESS project website (https://ssg.group.shef.ac.uk/progress2/html/index.phtml).

  10. Neutron cross section evaluations of europium isotopes in 1 keV - 30 MeV energy range. Format - validation - comparison; Evaluation de sections efficaces pour des neutrons incidents sur des isotopes d'europium aux energies 1 keV - 30 MeV. Format - validation - comparaison

    Dossantos-Uzarralde, P.; Le Luel, C.; Bauge, E. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee

    2004-07-01

    This paper presents neutron cross section evaluations of Europium isotopes. The cross sections are evaluated in 1 keV - 30 MeV energy range for the isotopes {sup 146}Eu, {sup 147}Eu, {sup 148}Eu, {sup 149}Eu, {sup 150}Eu, {sup 151}Eu, {sup 152}Eu, {sup 153}Eu, {sup 154}Eu in their ground state. This evaluation includes cross section productions of the long life isomeric states. Special attention is put on the options used for the description of the files written in ENDF-6 format. The final issue is a proposal of a new breed of ENDF-6 formatted neutron activation file. (authors)

  11. New observations for the triggering of 178m2Hf isomer embedded in Ta matrix by 25 keV electrons

    178m2Hf isomer triggering has been studied using new experimental setup developed at Kharkov National University and installed at Kyiv Institute for Nuclear Research. The target presenting a single Ta foil of 100 μm thickness with 178m2Hf isomeric activity of 5 Bq has been irradiated by 25 keV electron beam. The enhanced counting rates of all the ground-state band transitions, just as γ89 keV isomeric and γ216 keV 8--state band transitions have been observed. Our data are consistent with an estimate for the triggering effect of 2.8 ±0.8 % and corresponding triggering cross-section can qualitatively be estimated as σtrig = 5.4·1027 cm2

  12. Compact Source of Electron Beam with Energy of 200 kEv and Average Power of 2 kW

    Kazarezov, Ivan; Balakin, Vladimir E; Bryazgin, Alex; Bulatov, Alexandre; Glazkov, Ivan; Kokin, Evgeny; Krainov, Gennady; Kuznetsov, Gennady I; Molokoedov, Andrey; Tuvik, Alfred

    2005-01-01

    The paper describes a compact electron beam source with average electron energy of 200 keV. The source operates with pulse power up to 2 MW under average power not higher than 2 kW, pulsed beam current up to 10 A, pulse duration up to 2 mks, and repetition rate up to 5 kHz. The electron beam is extracted through aluminium-beryllium alloy foil. The pulse duration and repetition rate can be changed from control desk. High-voltage generator for the source with output voltage up to 220 kV is realized using the voltage-doubling circuit which consists of 30 sections. The insulation type - gas, SF6 under pressure of 8 atm. The cooling of the foil supporting tubes is provided by a water-alcohol mixture from an independent source. The beam output window dimensions are 180?75 mm, the energy spread in the beam +10/-30%, the source weight is 80 kg.

  13. VizieR Online Data Catalog: 2-10keV luminosity function of AGN (Ranalli+, 2016)

    Ranalli, P.; Koulouridis, E.; Georgantopoulos, I.; Fotopoulou, S.; Hsu, L.-T.; Salvato, M.; Comastri, A.; Pierre, M.; Cappelluti, N.; Carrera, F. J.; Chiappetti, L.; Clerc, N.; Gilli, R.; Iwasawa, K.; Pacaud, F.; Paltani, S.; Plionis, E.; Vignali, C.

    2016-02-01

    The XMM-LSS, XMM-CDFS, and XMM-COSMOS are three surveys with complementary properties in terms of luminosity and redshift coverage. We used these three surveys to derive Bayesian estimates of the unabsorbed luminosity function (LF) of AGN in the 2-10keV band. The LF estimates are presented as a set of samples from the posterior probability distribution of the LF parameters. The LF is parameterised as a double power-law, with either the luminosity and density evolution (LADE) model, or the luminosity-dependent density evolution (LDDE) model. The double power-law is described by Eq.(10) in the paper. The LADE and LDDE models are described by Eqs.(11-14) and Eqs.(15-17), respectively. A Fortran 2008 implementation of these models can be found in file src2/lumf_funcs.f90 of the LFTools package, in the classes doublepowerlaw, ladevol, and lddevol (see the paper). (8 data files).

  14. The 1 keV to 200 keV X-ray Spectrum of NGC 2992 and NGC 3081

    Beckmann, Volker; Tueller, Jack

    2007-01-01

    The Seyfert 2 galaxies NGC 2992 and NGC 3081 have been observed by INTEGRAL and Swift. We report about the results and the comparison of the spectrum above 10 keV based on INTEGRAL IBIS/ISGRI, Swift/BAT, and BeppoSAX/PDS. A spectrum can be extracted in the X-ray energy band ranging from 1 keV up to 200 keV. Although NGC 2992 shows a complex spectrum below 10 keV, the hard tail observed by various missions exhibits a slope with photon index = 2, independent on the flux level during the observation. No cut-off is detectable up to the detection limit around 200 keV. In addition, NGC 3081 is detected in the INTEGRAL and Swift observation and also shows an unbroken Gamma = 1.8 spectrum up to 150 keV. These two Seyfert galaxies give further evidence that a high-energy cut-off in the hard X-ray spectra is often located at energies E_C >> 100 keV. In NGC 2992 a constant spectral shape is observed over a hard X-ray luminosity variation by a factor of 11. This might indicate that the physical conditions of the emitting...

  15. Electric properties of biodiesel in the range from 20 Hz to 20 MHz. Comparison with diesel fossil fuel

    Gonzalez Prieto, L.E. [Grupo de Energias Renovables, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850, Buenos Aires, 1063 (Argentina); Sorichetti, P.A. [Laboratorio de Sistemas Liquidos, Facultad de Ingenieria, Universidad de Buenos Aires, Buenos Aires (Argentina); Romano, S.D. [Grupo de Energias Renovables, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850, Buenos Aires, 1063 (Argentina); CONICET: Consejo Nacional de Investigaciones Cientificas y Tecnicas, Av. Rivadavia 1917, Buenos Aires, 1033 (Argentina)

    2008-07-15

    Determination of electric properties at the different steps of biodiesel (BD) production contributes to a better understanding of the influence of the variables. Measurements of complex permittivity and conductivity make possible to survey efficiently the diverse steps of the industrial-scale production process, from the conditioning of the raw material to the quality control of the final product. Moreover, electrical measurements are 'non-destructive' and require relatively small sample volumes. In this work, complex permittivity spectra of BD and DF from 20 Hz to 20 MHz are presented. Experimental data were taken in a range of temperatures from 25 to 75 C, measured with an accuracy of {+-}0.1 C. The measuring system used in this work requires a sample volume of 25cm{sup 3} and gives the real part of permittivity ({epsilon}{sup '}) with an accuracy better than 1%. Dielectric loss (tg{delta}) can be measured between 10{sup -2} and 10{sup 2}. (author)

  16. Cross-field diffusion of energetic (100 keV to 2 MeV) protons in interplanetary space

    Costa Jr, Edio da [Instituto Federal de Minas Gerais-IFMG, Ouro Preto, MG, 35400-000 (Brazil); Tsurutani, Bruce T. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Alves, Maria Virgínia; Echer, Ezequiel [Instituto Nacional de Pesquisas Espaciais-INPE, São José dos Campos, SP, 12227-010 (Brazil); Lakhina, Gurbax S., E-mail: edio.junior@ifmg.edu.br, E-mail: costajr.e@gmail.com [Indian Institute for Geomagnetism, Navi Mumbai 410 218 (India)

    2013-12-01

    Magnetic field magnitude decreases (MDs) are observed in several regions of the interplanetary medium. In this paper, we characterize MDs observed by the Ulysses spacecraft instrumentation over the solar south pole by using magnetic field data to obtain the empirical size, magnetic field MD, and frequency of occurrence distribution functions. The interaction of energetic (100 keV to 2 MeV) protons with these MDs is investigated. Charged particle and MD interactions can be described by a geometrical model allowing the calculation of the guiding center shift after each interaction. Using the distribution functions for the MD characteristics, Monte Carlo simulations are used to obtain the cross-field diffusion coefficients as a function of particle kinetic energy. It is found that the protons under consideration cross-field diffuse at a rate of up to ≈11% of the Bohm rate. The same method used in this paper can be applied to other space regions where MDs are observed, once their local features are well known.

  17. Studies towards the understanding of the effects of ionizing radiations at the molecular scale (20-150 keV H+/H + He Collisions; dissociative electron attachment to water)

    This work comes within the scope of recent studies towards a better understanding of the effect of ionizing radiation at the molecular scale on biological systems. It is composed of two parts. The first one presents a new set of coincidence measurements of cross sections for the impact of protons or hydrogen atoms on helium in the energy range 20-150 keV of interest for the radiation biology. It is an archetypical system of interest for the theoreticians and there exists only a few studies on the impact of hydrogen atoms on helium. This study with helium was also motivated for the sake of performing a general test of functioning of the apparatus before investigating more complicated systems. Similar studies were then performed by replacing helium with water and biological molecules of relevance (Uracil, Thymine...) as target. This constitutes a study of direct effects of fast ionizing radiations on molecules of biological interest. The second part of the thesis deals with another type of ionizing radiations which can be seen as indirect effects of the first fast ionizing radiations studied in the first part. Low energy electrons emission in the energy range 1 to 16 eV follows the bombardment of the matter by swift protons/hydrogen atoms; these electrons have in turn an ionizing influence on the environment. A review of the dissociative electron attachment to water was undertaken motivated by the existing discrepancies between old studies on the same subject. A special attention was given to the problem of high energy kinetic ion discrimination in the trochoidal monochromator used for this work. (author)

  18. Studies towards the understanding of the effects of ionizing radiations at the molecular scale (20-150 keV H{sup +}/H + He Collisions; dissociative electron attachment to water)

    Coupier, B

    2005-11-15

    This work comes within the scope of recent studies towards a better understanding of the effect of ionizing radiation at the molecular scale on biological systems. It is composed of two parts. The first one presents a new set of coincidence measurements of cross sections for the impact of protons or hydrogen atoms on helium in the energy range 20-150 keV of interest for the radiation biology. It is an archetypical system of interest for the theoreticians and there exists only a few studies on the impact of hydrogen atoms on helium. This study with helium was also motivated for the sake of performing a general test of functioning of the apparatus before investigating more complicated systems. Similar studies were then performed by replacing helium with water and biological molecules of relevance (Uracil, Thymine...) as target. This constitutes a study of direct effects of fast ionizing radiations on molecules of biological interest. The second part of the thesis deals with another type of ionizing radiations which can be seen as indirect effects of the first fast ionizing radiations studied in the first part. Low energy electrons emission in the energy range 1 to 16 eV follows the bombardment of the matter by swift protons/hydrogen atoms; these electrons have in turn an ionizing influence on the environment. A review of the dissociative electron attachment to water was undertaken motivated by the existing discrepancies between old studies on the same subject. A special attention was given to the problem of high energy kinetic ion discrimination in the trochoidal monochromator used for this work. (author)

  19. Introducing ADS 2.0

    Accomazzi, Alberto; Kurtz, M. J.; Henneken, E. A.; Grant, C. S.; Thompson, D.; Luker, J.; Chyla, R.; Murray, S. S.

    2014-01-01

    In the spring of 1993, the Smithsonian/NASA Astrophysics Data System (ADS) first launched its bibliographic search system. It was known then as the ADS Abstract Service, a component of the larger Astrophysics Data System effort which had developed an interoperable data system now seen as a precursor of the Virtual Observatory. As a result of the massive technological and sociological changes in the field of scholarly communication, the ADS is now completing the most ambitious technological upgrade in its twenty-year history. Code-named ADS 2.0, the new system features: an IT platform built on web and digital library standards; a new, extensible, industrial strength search engine; a public API with various access control capabilities; a set of applications supporting search, export, visualization, analysis; a collaborative, open source development model; and enhanced indexing of content which includes the full-text of astronomy and physics publications. The changes in the ADS platform affect all aspects of the system and its operations, including: the process through which data and metadata are harvested, curated and indexed; the interface and paradigm used for searching the database; and the follow-up analysis capabilities available to the users. This poster describes the choices behind the technical overhaul of the system, the technology stack used, and the opportunities which the upgrade is providing us with, namely gains in productivity and enhancements in our system capabilities.

  20. WMS Server 2.0

    Plesea, Lucian; Wood, James F.

    2012-01-01

    This software is a simple, yet flexible server of raster map products, compliant with the Open Geospatial Consortium (OGC) Web Map Service (WMS) 1.1.1 protocol. The server is a full implementation of the OGC WMS 1.1.1 as a fastCGI client and using Geospatial Data Abstraction Library (GDAL) for data access. The server can operate in a proxy mode, where all or part of the WMS requests are done on a back server. The server has explicit support for a colocated tiled WMS, including rapid response of black (no-data) requests. It generates JPEG and PNG images, including 16-bit PNG. The GDAL back-end support allows great flexibility on the data access. The server is a port to a Linux/GDAL platform from the original IRIX/IL platform. It is simpler to configure and use, and depending on the storage format used, it has better performance than other available implementations. The WMS server 2.0 is a high-performance WMS implementation due to the fastCGI architecture. The use of GDAL data back end allows for great flexibility. The configuration is relatively simple, based on a single XML file. It provides scaling and cropping, as well as blending of multiple layers based on layer transparency.

  1. DC CONDUCTIVITY OF CERAMICS WITH CALCITE WASTE IN THE TEMPERATURE RANGE 20 - 1050C

    Jan Ondruska

    2015-06-01

    Full Text Available The temperature dependences of the electrical DC conductivity of calcite waste, kaolinite and illite based ceramics were measured in the temperature range of 20 - 1050oC. The ceramic mass that was used was a mixture of 60 wt. % kaolinitic-illitic clay, 20 - 40 wt. % of this clay was fired at 1000oC for 90 min and 0, 10 and 20 wt. % of calcite waste. During heating, several processes take place - the release of the physically bound water, the burning of organic impurities, the dehydroxylation of kaolinite and illite, the decomposition of calcite, and the creation of anorthite and mullite. All of these processes were checked by means of differential thermal analysis (DTA, derivative thermogravimetry (DTG and thermodilatometry (TDA. At low temperatures (20 - 200oC, due to the release and decomposition of physically bound water, H+ and OH- are dominant charge carriers. After completion of release of physically bound water, up to the start of dehydroxylation at the temperature of ~ 450oC, the DC conductivity is dominated by a transport of Na+, K+, and Ca2+ ions. During dehydroxylation, H+ and OH- ions, which are released from kaolinite and illite lattices, contribute to the DC conductivity. Decomposition of calcite runs between ~ 700oC and 900oC. The glassy phase has a dominant influence on the DC conductivity in the fired ceramics. Its high conductivity is determined by the high mobility of Na+, K+, and Ca2+ ions.

  2. Non-dissociative and dissociative ionization of N2, CO, CO2, and CH4 by impact of 50-6000 keV protons and antiprotons

    Measurements of the cross section for non-dissociative single ionization and the cross sections for the creation of charged fragments have been performed for 50-6000 keV antiproton and proton impact on N2, CO, CO2, and CH4. The results support the understanding of the ionization phenomenon that has been achieved via measurements with fundamental charged particles on atoms. The present high-energy antiproton fragmentation data supply a stringent test of the validity of the published electron-impact fragmentation data which, unfortunately, most of them fail. (Author)

  3. THE ORIGIN OF THE 6.4 keV LINE EMISSION AND H{sub 2} IONIZATION IN THE DIFFUSE MOLECULAR GAS OF THE GALACTIC CENTER REGION

    Dogiel, V. A.; Chernyshov, D. O. [I. E. Tamm Theoretical Physics Division of P. N. Lebedev Institute of Physics, Leninskii pr. 53, 119991 Moscow (Russian Federation); Tatischeff, V. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, IN2P3/CNRS and Univ Paris-Sud, F-91405 Orsay Campus (France); Cheng, K.-S. [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (Hong Kong); Terrier, R. [Astroparticule et Cosmologie, Universite Paris7/CNRS/CEA, Batiment Condorcet, F-75013 Paris (France)

    2013-07-10

    We investigate the origin of the diffuse 6.4 keV line emission recently detected by Suzaku and the source of H{sub 2} ionization in the diffuse molecular gas of the Galactic center (GC) region. We show that Fe atoms and H{sub 2} molecules in the diffuse interstellar medium of the GC are not ionized by the same particles. The Fe atoms are most likely ionized by X-ray photons emitted by Sgr A* during a previous period of flaring activity of the supermassive black hole. The measured longitudinal intensity distribution of the diffuse 6.4 keV line emission is best explained if the past activity of Sgr A* lasted at least several hundred years and released a mean 2-100 keV luminosity {approx}> 10{sup 38} erg s{sup -1}. The H{sub 2} molecules of the diffuse gas cannot be ionized by photons from Sgr A*, because soft photons are strongly absorbed in the interstellar gas around the central black hole. The molecular hydrogen in the GC region is most likely ionized by low-energy cosmic rays, probably protons rather than electrons, whose contribution into the diffuse 6.4 keV line emission is negligible.

  4. Thermal Stability of Austempered Ductile Iron Evaluated in a Temperature Range of 20-300K

    Dawid MYSZKA

    2016-05-01

    Full Text Available The aim of this article was to determine through changes in magnetic properties the stability of the austempered ductile iron (ADI microstructure during temperature changes in a range of 20 – 300 K. The measurements were taken in a vibrating sample magnetometer (VSM using Fe27Ni2TiMoAlNb austenitic stainless steel and four types of austempered ductile iron obtained under various heat treatment conditions. The plotted curves showing changes in the magnetisation degree as a function of temperature had a number of characteristic points illustrating changes taking place in the microstructure. For each of the materials examined, the martensite start temperature Ms and the temperature range within which the martensitic transformation takes place were identified.

  5. The temperature effect on the glycine decomposition induced by 2 keV electron bombardment in space analog conditions

    Pilling, Sergio; Nair, Binu G.; Escobar, Antonio; Fraser, Helen; Mason, Nigel

    2014-03-01

    Glycine is the simplest proteinaceous amino acid that has been extensively detected in carbonaceous meteorites and was recently observed in the cometary samples returned to Earth by NASA's Stardust spacecraft. In space, such species is exposed to several radiation fields at different temperatures. In aqueous solutions, this species appears mainly as zwitterionic glycine (+NH3CH2COO-) however, in solid phase, it may be found in amorphous or crystalline forms. Here, we present an experimental study on the destruction of two zwitterionic glycine crystals ( α- and β-form) at two different temperatures (300 K and 14 K) by 2 keV electrons in an attempt to test the behavior and stability of this molecular species in different space environments. The samples were analyzed in situ by Fourier transform infrared spectrometry at electron fluences. The experiments were carried out under ultra-high vacuum conditions at the Molecular Physics Laboratory at the Open University at Milton Keynes, UK. The dissociation cross section of glycine is approximately 5 times higher for the 14 K samples when compared to the 300 K samples. In contrast, no significant differences emerged between the dissociation cross sections of α- and β-forms of glycine for fixed temperature experiments. We therefore conclude that the destruction cross section is more heavily dependent on temperature than the phase of the condensed glycine material. This may be associated with the opening of additional reaction routes in the frozen samples involving the trapped daughter species (e.g. CO2 and CO). The half-life of studied samples extrapolated to space conditions shows that glycine molecules on the surface of interstellar grains has less survivability and they are highly sensitive to ambient radiations, however, they can survive extended period of time in the solar system like environments. Survivability increases by a factor of 5 if the samples are at 300 K when compared to low temperature experiments at 14

  6. 7 CFR 20.2 - Administration.

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Administration. 20.2 Section 20.2 Agriculture Office of the Secretary of Agriculture EXPORT SALES REPORTING REQUIREMENTS § 20.2 Administration. The regulations of this part will be administered by the Foreign Agricultural Service (FAS) under the...

  7. Determination of the molecular structure via the medium energy electrons (500 eV-1,5 KeV) Ar, N2, Co e HCl

    Elastic Differential and Total Differential Cross Sections are measured for electron collision in medium-energy range (500 eV - 1,5 KeV) with argon, nitrogen, carbon monoxide and hydrogen chloride, all in their electronic ground state. Theoretical calculation for the Elastic Differential Cross Sections by atoms were done employing Hartree-Fock-Clementy wave function, and making use of Partial Wave and WKBJ Methods. Exchange effect is included in the case of argon. Independent Atom Model, Half Molecule Model and a new model, the Ionic Model were utilized for the molecular calculations. The Ionic Model is suggested for the interaction between HCl and electrons. Inelastic Differential Cross Section were also computed, making use of the First Born Approximation and Hartree-Fock-Clementi wave function. It is also demonstrated, for the first time, that medium energy electrons (500 eV - 1,5 Kev) can be used to determine molecular structure parameters, in gas phase

  8. Source IST 2.0 validation approach

    SOURCE IST 2.0 is a code for calculating the release of fission products from the fuel pellets to the surrounding environment. For most accidents that environment is the Primary Heat Transport System. For other scenarios (such as End-Fitting Failures and Fuel Handling Accidents) it would be the containment atmosphere. The validation approach being used by the Canadian nuclear industry is founded on the use of: the Technical Basis Document (which describes controlling phenomena that apply in each phase of a postulated accident), discipline-specific Validation Matrices (which relate phenomena and ranges of conditions to experimental data sets), and code-specific Validation Plans (which list the data sets to be simulated and describe their coverage of controlling phenomena and accident conditions). The controlling phenomena for fission product release from fuel are modelled in the code. For some of these phenomena detailed physical models are employed, but for others assumptions or approximations that lead to limiting consequences are used. This combination of best-estimate and limit-consequence models poses interesting challenges in interpreting validation results. The nature of SOURCE IST 2.0 as an industry standard tool being developed for multiple platforms has imposed certain requirements on validation activities, e.g., portable test cases, reproducing tests on multiple platforms. This paper describes the approach adopted for SOURCE IST 2.0 in the context of the constraints imposed by the nature of the problem being solved, the nature of the solution methodology selected, and the multi-platform requirements. SOURCE IST 2.0 will be validated using Canadian and international separate effects and in-reactor experimental data sets. (author)

  9. Quite time convection electric field properties derived from keV electron measurements at the inner edge of the plasma sheet by means of GEOS 2

    From an analysis of the local time distribution of the electron upper energy limit reached by the geostationary satellite GEOS 2 in cutting through the innermost part of the electron plasma sheet during fairly quite condition the following results have been obtained, among others: An electric field model given by E = -grad(AR4 sinphi), with the dusk singular point of the forbidden region boundary at 1500, instead of at 1800 MLT, is in quite good agreement with the observations. This means that effects due to the shielding by the hot plasma of the inner magnetosphere from the convection electric field are quite strong in situations of low disturbance level. The quiet time convection electric field strength at 2100 MLT in the geostationary orbit obtained from this analysis varies in the range 0.15 - 0.3 keV/Rsub(e). Six hours earlier or later in the satellite orbit the convection field is 4 times stronger. Also when the convection field varies, some information about its magnitude can be obtained from the keV electron measurements. (author)

  10. Indicadores 2.0 para la ciencia 2.0

    Torres Salinas, Daniel

    2009-01-01

    Comunicación presentada en el 9º Workshop de Rebiun sobre proyectos digitales, Investigación, innovación e información: tendencias en los sistemas digitales de gestión de la producción científica, celebrado en Salamanca los días 1 y 2 de octubre de 2009.

  11. An experimental study of charge exchange process in the energy range 1-30 keV during the passage of alkali metal ions and atoms through cesium and potassium vapour

    An experimental study is presented of the charge exchange processes in the energy range of about 1-30 keV during the passage of positive alkali ions and alkali atoms through potassium and cesium vapour. The experimental set-up designed for this experiment includes a thermionic source for positive alkali ions with an acceleration stage, a first charge exchange cell to produce fast alkali atoms, a second charge exchange cell with a surface ionisation detector to determine the alkali metal vapor target thickness and a detection system with electrostatic bending of the charged secondary species. The maximum negative ion yield has been determined for the collision systems Li+ + K, Na+ + K, K+ + K, and Rb+ + K, and for another eleven systems the charge transfer cross-sections have been measured too. (orig./GG)

  12. Web2.0 Era of E-learning2.0%Web2.0时代的E-learning2.0

    邓国民

    2008-01-01

    web 2.0给我们带来了网络思维和网络应用方法的变革,也为 E-learning的教学模式提供了更多的支持,它将促成E-learning 2.0的产生.本文首先介绍Web 2.0的核心内容和特点,然后分析讨论了web 2.0在E-learning中的应用,最后对E-learning 2.0的特点和优势进行了总结.

  13. Web 2.0 i undervisningen

    Liburd, Janne J.; Christensen, Inger-Marie F.

    2011-01-01

    Temahæfte om web 2.0, der formidler viden om og inspiration til at arbejde med web 2.0 teknologier i videregående uddannelser. Hæftet introducerer sociale medier og web 2.0, og der redegøres for teoretisk funderede læreprocesser med web 2.0, og hvorledes disse kan indtænkes i undervisningsforløb....... Hæftet præsenterer endvidere en metode til design af læringsaktiviteter med web 2.0, og giver en række eksempler på konkrete forløb....

  14. The 2-10 keV unabsorbed luminosity function of AGN from the LSS, CDFS, and COSMOS surveys

    Ranalli, P.; Koulouridis, E.; Georgantopoulos, I.; Fotopoulou, S.; Hsu, L.-T.; Salvato, M.; Comastri, A.; Pierre, M.; Cappelluti, N.; Carrera, F. J.; Chiappetti, L.; Clerc, N.; Gilli, R.; Iwasawa, K.; Pacaud, F.; Paltani, S.; Plionis, E.; Vignali, C.

    2016-05-01

    The XMM-Large scale structure (XMM-LSS), XMM-Cosmological evolution survey (XMM-COSMOS), and XMM-Chandra deep field south (XMM-CDFS) surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and point spread function. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of active galactic nuclei (AGN) and their evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 1042-1046 erg s-1 and in the redshift interval 0.001-4. A new method to correct for absorption by considering the probability distribution for the column density conditioned on the hardness ratio is presented. The binned luminosity function and its evolution is determined with a variant of the Page-Carrera method, which is improved to include corrections for absorption and to account for the full probability distribution of photometric redshifts. Parametric models, namely a double power law with luminosity and density evolution (LADE) or luminosity-dependent density evolution (LDDE), are explored using Bayesian inference. We introduce the Watanabe-Akaike information criterion (WAIC) to compare the models and estimate their predictive power. Our data are best described by the LADE model, as hinted by the WAIC indicator. We also explore the recently proposed 15-parameter extended LDDE model and find that this extension is not supported by our data. The strength of our method is that it provides unabsorbed, non-parametric estimates, credible intervals for luminosity function parameters, and a model choice based on predictive power for future data. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and NASA.Tables with the samples of the posterior probability distributions

  15. The PLATO 2.0 Mission

    Rauer, H; Aerts, C; Appourchaux, T; Benz, W; Brandeker, A; Christensen-Dalsgaard, J; Deleuil, M; Gizon, L; Güdel, M; Janot-Pacheco, E; Mas-Hesse, M; Pagano, I; Piotto, G; Pollacco, D; Santos, N C; Smith, A; -C., J; Suárez,; Szabó, R; Udry, S; Adibekyan, V; Alibert, Y; Almenara, J -M; Amaro-Seoane, P; Eiff, M Ammler-von; Antonello, E; Ball, W; Barnes, S; Baudin, F; Belkacem, K; Bergemann, M; Birch, A; Boisse, I; Bonomo, A S; Borsa, F; Brandão, I M; Brocato, E; Brun, S; Burleigh, M; Burston, R; Cabrera, J; Cassisi, S; Chaplin, W; Charpinet, S; Chiappini, C; Csizmadia, Sz; Cunha, M; Damasso, M; Davies, M B; Deeg, H J; Fialho, F de Oliveira; DÍaz, R F; Dreizler, S; Dreyer, C; Eggenberger, P; Ehrenreich, D; Eigmüller, P; Erikson, A; Farmer, R; Feltzing, S; Figueira, P; Forveille, T; Fridlund, M; García, R; Giuffrida, G; Godolt, M; da Silva, J Gomes; Goupil, M -J; Granzer, T; Grenfell, J L; Grotsch-Noels, A; Günther, E; Haswell, C A; Hatzes, A P; Hébrard, G; Hekker, S; Helled, R; Heng, K; Jenkins, J M; Khodachenko, M L; Kislyakova, K G; Kley, W; Kolb, U; Krivova, N; Kupka, F; Lammer, H; Lanza, A F; Lebreton, Y; Magrin, D; Marcos-Arenal, P; Marrese, P M; Marques, J P; Martins, J; Mathis, S; Mathur, S; Messina, S; Miglio, A; Montalban, J; Montalto, M; Monteiro, M J P F G; Moradi, H; Moravveji, E; Mordasini, C; Morel, T; Mortier, A; Nascimbeni, V; Nielsen, M B; Noack, L; Norton, A J; Ofir, A; Oshagh, M; Ouazzani, R -M; Pápics, P; Parro, V C; Petit, P; Plez, B; Poretti, E; Quirrenbach, A; Ragazzoni, R; Raimondo, G; Rainer, M; Reese, D R; Redmer, R; Reffert, S; Rojas-Ayala, B; Roxburgh, I W; Solanki, S K; Salmon, S; Santerne, A; Schneider, J; Schou, J; Schuh, S; Schunker, H; Silva-Valio, A; Silvotti, R; Skillen, I; Snellen, I; Sohl, F; Sousa, A S; Sozzetti, A; Stello, D; Strassmeier, K G; Švanda, M; Szabó, G M; Tkachenko, A; Valencia, D; van Grootel, V; Vauclair, S D; Ventura, P; Wagner, F W; Walton, N A; Weingrill, J; Werner, S C; Wheatley, P J; Zwintz, K

    2013-01-01

    PLATO 2.0 is a mission candidate for ESA's M3 launch opportunity (2022/24). It addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, able to develop life? The PLATO 2.0 instrument consists of 34 small aperture telescopes providing a wide field-of-view and a large photometric magnitude range. It targets bright stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for stars <=11mag to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2%, 4-10% and 10% for planet radii, masses and ages, respectively. The foreseen baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into t...

  16. Sputtering of solid neon by keV hydrogen ions

    Ellegaard, Ole; Schou, Jørgen; Sørensen, H.

    Sputtering of solid Ne with the hydrogen ions H+1, H+2 and H+3 in the energy range 1–10 keV/atom has been studied by means of a quartz microbalance technique. No enhancement in the yield per atom for molecular ions was found. The results for hydrogen ions are compared with data for keV electrons...

  17. FRAMES-2.0 Software System: Frames 2.0 Pest Integration (F2PEST)

    The implementation of the FRAMES 2.0 F2PEST module is described, including requirements, design, and specifications of the software. This module integrates the PEST parameter estimation software within the FRAMES 2.0 environmental modeling framework. A test case is presented.

  18. A determination of the Fano factor for germanium at 77.4K from measurements of the energy resolution of a 113cm3 HPGe gamma-ray spectrometer taken over the energy range from 14 to 6129 keV

    The Fano factor for germanium cooled to 77.4 K has been determined from a semiempirical analysis of the measured energy resolution of a HPGe γ-ray spectrometer of active volume 113.2 cm3. Twenty nine γ-ray energies spanning the range from 14 to 6129 keV were used in this study. The dispersion due to incomplete charge collection was assessed experimentally by making measurements over a wide range of applied bias. Plots of the peak centroid shift and the peak width squared against the reciprocal of the voltage applied to the detector, were non-linear. Both exhibited plateaus for large applied voltages. Thus, by operating in the plateau region, the Fano factor could be extracted from the variation of the observed line width as a function of energy, while the detector was known to be functioning close to the position of perfect charge collection. The value of the Fano factor obtained in this work, averaged over the energy range 14-6129 keV, was 0.112 ± 0.001. It is recommended that more, high quality, measurements be made. (author)

  19. Germanium thermometers in the temperature range .1000K to 4.20K

    The sensitivity characteristics of two germanium thermometers that proved to be convenient sensors in the temperature range from .1000K to 4.20K, are described. Their resistances change from about 8 x 105 ohms at .1000K to about 100 ohms at 4.20K. The calibration curves were fitted to natural spline functions of order 3 in the whole range of temperatures. These functions give less than half millidegree standard dispersion against 15 millidegree standard dispersion when usual polynomial interpolations are used. It is discussed what spline functions are, and compare the goodness of spline interpolation with polynomial methods

  20. Web 2.0: A Strategy Guide

    Shuen, Amy

    2008-01-01

    Web 2.0 makes headlines, but how does it make money? This concise guide explains what's different about Web 2.0 and how those differences can improve the bottom line. Whether you're an executive, a small business owner, or an entrepreneur, Web 2.0: A Strategy Guide illustrates through real life examples how various businesses are creating new opportunities on today's Web. This book is about strategy rather than the technology itself.

  1. DISFRAC Version 2.0 Users Guide

    Cochran, Kristine B [ORNL; Erickson, Marjorie A [ORNL; Williams, Paul T [ORNL; Klasky, Hilda B [ORNL; Bass, Bennett Richard [ORNL

    2013-01-01

    DISFRAC is the implementation of a theoretical, multi-scale model for the prediction of fracture toughness in the ductile-to-brittle transition temperature (DBTT) region of ferritic steels. Empirically-derived models of the DBTT region cannot legitimately be extrapolated beyond the range of existing fracture toughness data. DISFRAC requires only tensile properties and microstructural information as input, and thus allows for a wider range of application than empirical, toughness data dependent models. DISFRAC is also a framework for investigating the roles of various microstructural and macroscopic effects on fracture behavior, including carbide particle sizes, grain sizes, strain rates, and material condition. DISFRAC s novel approach is to assess the interaction effects of macroscopic conditions (geometry, loading conditions) with variable microstructural features on cleavage crack initiation and propagation. The model addresses all stages of the fracture process, from microcrack initiation within a carbide particle, to propagation of that crack through grains and across grain boundaries, finally to catastrophic failure of the material. The DISFRAC procedure repeatedly performs a deterministic analysis of microcrack initiation and propagation within a macroscopic crack plastic zone to calculate a critical fracture toughness value for each microstructural geometry set. The current version of DISFRAC, version 2.0, is a research code for developing and testing models related to cleavage fracture and transition toughness. The various models and computations have evolved significantly over the course of development and are expected to continue to evolve as testing and data collection continue. This document serves as a guide to the usage and theoretical foundations of DISFRAC v2.0. Feedback is welcomed and encouraged.

  2. High-resolution detection of 100 keV electrons using avalanche photodiodes

    Ogasawara, K.; Hirahara, M.; Miyake, W.; Kasahara, S.; Takashima, T.; Asamura, K.; Saito, Y.; Mukai, T.

    2008-08-01

    With two electron beam sources, we have tested two new Hamamatsu [Hamamatsu Photonics K.K., Shizuoka, Japan ] avalanche photodiodes (APDs) of spl 3988 and spl 6098 to detect electron beams up to 100 keV. Though our previous results showed the effectiveness and the advantage of an APD to measure 2-40 keV electrons, its upper limit was not high enough to detect so-called medium-energy electrons. In addition to the limitation of its detectable range, the response at different energies was also not linear. These newly developed APDs, which have thicker depletion-layers, provide full coverage of this missing range along with a good linearity. The depletion-layer thickness was increased to 140 μm for both APDs, the dead-layer of spl 3988 became 10 times thicker than that of spl 6098. The thin-surface dead-layer and thick depletion-layer of spl 6098 allows the detection of electrons from 3 keV up to 100 keV with a good linearity and with an excellent energy resolution of 4 keV at 100-keV electrons. The wide dynamic range from 3 keV to 100 keV of those APDs will increase their appeal in detecting electrons for space plasma research.

  3. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

    Mohd Yusof, Mohd Fahmi, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-29

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

  4. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

  5. Performance of TEPCs at low pressures: some attempts to improve their dose equivalent response to the neutron energy range from 10keV to 1 MeV

    A TEPC, from its operational principle, fulfils reasonably well the requirements of an area monitor with a dose equivalent response nearly independent of neutron energy to be used for radiation protection dosimetry at various work places. However, between neutron energies from 10 keV to 1 MeV, which are of relevance for environments with strongly moderated neutron fields, the response of TEPCs with thin walls is too low. Attempts to increase the response in this energy region by modifying gas pressure, gas composition and wall thickness show that significant improvement first requires operation of the TEPC at lower simulated diameters compared with the 2 μm diameter commonly used. Preliminary investigations to improve the operational properties of TEPCs at low pressures are presented. (author)

  6. Verification of HEPA Filter Analysis for the Canberra Q2 Waste Assay System

    Casella, V.R.

    2002-12-06

    Data from measurements of a standard 20 inches x 20 inches source positioned on the end and in the middle of a HEPA filter verified that assaying HEPA filters with the Canberra Q2 and using the standard drum calibration with a percent full parameter of 70 percent gives acceptable results for gamma rays above 122 keV. For the gamma-ray energy range of 122 keV to 1400 keV, nuclide concentrations would be somewhat overestimated by from about 35 percent (122 keV) to about 10 percent (1400 keV). Also, Am-241 (60 keV) is conservatively overestimated by about a factor of 2.6 using this configuration.

  7. GEM Building Taxonomy (Version 2.0)

    Brzev, S.; Scawthorn, C.; Charleson, A.W.; Allen, L.; Greene, M.; Jaiswal, Kishor; Silva, V.

    2013-01-01

    This report documents the development and applications of the Building Taxonomy for the Global Earthquake Model (GEM). The purpose of the GEM Building Taxonomy is to describe and classify buildings in a uniform manner as a key step towards assessing their seismic risk, Criteria for development of the GEM Building Taxonomy were that the Taxonomy be relevant to seismic performance of different construction types; be comprehensive yet simple; be collapsible; adhere to principles that are familiar to the range of users; and ultimately be extensible to non-buildings and other hazards. The taxonomy was developed in conjunction with other GEM researchers and builds on the knowledge base from other taxonomies, including the EERI and IAEE World Housing Encyclopedia, PAGER-STR, and HAZUS. The taxonomy is organized as a series of expandable tables, which contain information pertaining to various building attributes. Each attribute describes a specific characteristic of an individual building or a class of buildings that could potentially affect their seismic performance. The following 13 attributes have been included in the GEM Building Taxonomy Version 2.0 (v2.0): 1.) direction, 2.)material of the lateral load-resisting system, 3.) lateral load-resisting system, 4.) height, 5.) date of construction of retrofit, 6.) occupancy, 7.) building position within a block, 8.) shape of the building plan, 9.) structural irregularity, 10.) exterior walls, 11.) roof, 12.) floor, 13.) foundation system. The report illustrates the pratical use of the GEM Building Taxonomy by discussing example case studies, in which the building-specific characteristics are mapped directly using GEM taxonomic attributes and the corresponding taxonomic string is constructed for that building, with "/" slash marks separating attributes. For example, for the building shown to the right, the GEM Taxonomy string is: DX1/MUR+CLBRS+MOCL2/LWAL3/

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

    Böke, Aysun

    2014-09-01

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

  9. Energy-discrimination X-ray computed tomography system utilizing a silicon-PIN detector and its application to 2.0-keV-width K-edge imaging

    Demonstration of narrow-energy-width computed tomography (CT) was carried out by means of energy-discrimination. An X-ray CT system is of a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a silicon-PIN detector system with amplifiers, a multi-channel analyzer (MCA), a counter card (CC), and a personal computer (PC). CT is accomplished by repeating the translation and the rotation of an object, and projection curves of the object are obtained by the translation of the moving object. Both photon-energy level and energy width are determined by the MCA, and the pulses of the discriminated event signal from the MCA are counted by CC in conjunction with PC. The maximum count rate was approximately 300 cps (counts per second) with energy widths of 2.0 keV, and energy-discrimination CT was carried out with a photon-energy resolution of 0.15 keV. To perform iodine K-edge CT, X-ray photons with an energy range from 33.2 to 35.2 keV were used. Next, to carry out cerium K-edge CT, an energy range from 40.3 to 42.3 keV was selected.

  10. Differential cross section of the reaction γ + p -> π+ + n at intermediate angles in the γ-energy range from 0.3 to 2.0 GeV and parametrization by expansion in Legendre-Polynomials

    The differential cross section of the reaction γp->π+n was increased in 6 excitation curves at pion laboratory angles from thetasub(lab)sup(π) = 350 to 850 in 100-steps. The γ-energy range extended from 0.3 GeV at thetasub(lab) = 350 to an angle-dependent maximum value which lied between 0.77 GeV at thetasub(lab)sup(π) = 350 and 1.94 GeV thetasub(lab)sup(π) = 850. The 705 measuring points are part of a comprehensive measuring program of this laboratory which has the aim of the establishment of a complete, consistent high precision data set for the differential cross sections of the π+ photoproduction in the resonance region. (orig./HSI)

  11. THE DEVELOPMENT OF A SUPER-STABLE DATUM POINT FOR MONITORING THE ENERGY SCALE OF ELECTRON SPECTROMETERS IN THE ENERGY RANGE UP TO 20 keV

    Vénos, Drahoslav; Zbořil, Miroslav; Kašpar, Jaromír; Dragoun, Otokar; Bonn, J.; Kovalík, Alojz; Lebeda, Ondřej; Lebedev, N. A.; Ryšavý, Miloš; Schlosser, K.; Špalek, Antonín; Weinheimer, C.

    2010-01-01

    Roč. 53, č. 3 (2010), s. 305-312. ISSN 0543-1972 R&D Projects: GA ČR GA202/06/0002; GA MŠk LA318; GA MŠk LC07050; GA MŠk LA08002 Institutional research plan: CEZ:AV0Z10480505 Keywords : nuclear transition energy * conversion electrons * electron spectrometer Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.154, year: 2010

  12. Search for galactic sources and X-ray bursts with spectrometers of the Kosmos-914 satellite in the energy range of 20-320 keV

    The results of observations carried out with two scintillation spectrometers of ''Kosmos-914'' satellite used for searches for bursts of galactic hard X-rays are described. The comparison of the results obtained with ''Kosmos-428'' and ''Kosmos-856'' satellites is given. The results of observation of the Whale constellation and the celestial sphere area near the centre of Galaxy are given, where, according to the data of ''Kosmos-428'' satellite the presence of X-ray sources was experted

  13. Simultaneous removal of NOX and SO2 from flue gases by energizing gases with electrons having energy in the range from 5 eV to 20 eV

    These notes report the results obtained with an experimental installation able to treat 100 Nm3/h of flue gases, installed at the Thermoelectrical Power Plant at Marghera. The experimental installation, operating on the principle of gas energizing, is able to remove simultaneously 40 to 50% of the NOX and about 100% of the SO2 contained in the flue gases. It is expected to achieve better efficiency in the removal of NOX by including in the system a bag filter which should favour removal reaction in the heterogeneous phase of NOX. Particulate concentration at output is between 2 and 5 mg/Nm3. A pulse generator designed and built by Enel was tested; the results were excellent, so work has begun on the preliminary planning of a 200 kW pulse generator that operates on the same principle. (author)

  14. The x-ray calibration facility of the laser integration line in the 0.9-10 keV range: The high energy x-ray source and some applications

    The laser integration line (LIL) located at CEA-CESTA is equipped with x-ray plasma diagnostics using different kinds of x-ray components such as filters, mirrors, crystals, detectors, and cameras. The CEA-DAM of Arpajon is currently developing x-ray calibration methods and carrying out absolute calibration of LIL x-ray photodetectors. To guarantee LIL measurements, detectors such as x-ray cameras must be regularly calibrated close to the facility. A new x-ray facility is currently available to perform these absolute x-ray calibrations. This paper presents the x-ray tube based high energy x-ray source delivering x-ray energies ranging from 0.9 to 10 keV by means of an anode barrel. The purpose of this source is mainly to calibrate LIL x-ray cameras but it can also be used to measure x-ray filter transmission of plasma diagnostics. Different x-ray absolute calibrations such as x-ray streak and framing camera yields, x-ray charge-coupled device quantum efficiencies, and x-ray filter transmissions are presented in this paper. A x-ray flat photocathode detector sensitivity calibration recently performed for a CEA Z-pinch facility is also presented.

  15. 2.0'erne - den sociale uddannelsespraksis

    Buhl, Mie

    2010-01-01

    Betegnelsen Web 2.0 indikerer en udvikling af digital teknologi, der giver brugerne nye muligheder for at være producenter og deltagere i netbaseret kommunikation. '2.0' er i de senere år blevet knyttet til forskellige udgivelser af bøger i relation tiluddannelsessystemet. Udgivelserne Skole 2.......0, Didaktik 2.0 og e-Læring på web 2.0 viser alle hen til en pågående proces, hvor det handler om at finde frem til pædagogikker og didaktikker, der kan matche teknologiens potentialer. Web 2.0 er ikke alene det, der udspiller sig ved at aktivere et interface. Interfacet er omgivet af digitale artefakter, der...... giver anledning til at tænke uddannelsespraksis i nye formater.Denne artikel vil handle om, hvordan web 2.0 og nye digitale artefakter udfordrer os til at flytte os i de didaktiske tænkemodeller, vi almindeligvis anvender i undervisning og læring....

  16. Web 2.0感性

    2005-01-01

    很多人都在问,什么是Web2.0,他本质的东西是什么。目前业界对Web 2.0在观点上达成一致的地方,主要集中在Web 2.0所具备的三个特定,第一个是分众效应,第二个是互动性,第三个是原创性。

  17. LSST Science Book, Version 2.0

    Allison, Julius; Andrew, John R; Angel, J Roger P; Armus, Lee; Arnett, David; Asztalos, S J; Axelrod, Tim S; Bailey, Stephen; Ballantyne, D R; Bankert, Justin R; Barkhouse, Wayne A; Barr, Jeffrey D; Barrientos, L Felipe; Barth, Aaron J; Bartlett, James G; Becker, Andrew C; Becla, Jacek; Beers, Timothy C; Bernstein, Joseph P; Biswas, Rahul; Blanton, Michael R; Bloom, Joshua S; Bochanski, John J; Boeshaar, Pat; Borne, Kirk D; Bradac, Marusa; Brandt, W N; Bridge, Carrie R; Brown, Michael E; Brunner, Robert J; Bullock, James S; Burgasser, Adam J; Burge, James H; Burke, David L; Cargile, Phillip A; Chandrasekharan, Srinivasan; Chartas, George; Chesley, Steven R; Chu, You-Hua; Cinabro, David; Claire, Mark W; Claver, Charles F; Clowe, Douglas; Connolly, A J; Cook, Kem H; Cooke, Jeff; Cooray, Asantha; Covey, Kevin R; Culliton, Christopher S; de Jong, Roelof; de Vries, Willem H; Debattista, Victor P; Delgado, Francisco; Dell'Antonio, Ian P; Dhital, Saurav; Di Stefano, Rosanne; Dickinson, Mark; Dilday, Benjamin; Djorgovski, S G; Dobler, Gregory; Donalek, Ciro; Dubois-Felsmann, Gregory; Durech, Josef; Eliasdottir, Ardis; Eracleous, Michael; Eyer, Laurent; Falco, Emilio E; Fan, Xiaohui; Fassnacht, Christopher D; Ferguson, Harry C; Fernandez, Yanga R; Fields, Brian D; Finkbeiner, Douglas; Figueroa, Eduardo E; Fox, Derek B; Francke, Harold; Frank, James S; Frieman, Josh; Fromenteau, Sebastien; Furqan, Muhammad; Galaz, Gaspar; Gal-Yam, A; Garnavich, Peter; Gawiser, Eric; Geary, John; Gee, Perry; Gibson, Robert R; Gilmore, Kirk; Grace, Emily A; Green, Richard F; Gressler, William J; Grillmair, Carl J; Habib, Salman; Haggerty, J S; Hamuy, Mario; Harris, Alan W; Hawley, Suzanne L; Heavens, Alan F; Hebb, Leslie; Henry, Todd J; Hileman, Edward; Hilton, Eric J; Hoadley, Keri; Holberg, J B; Holman, Matt J; Howell, Steve B; Infante, Leopoldo; Ivezic, Zeljko; Jacoby, Suzanne H; Jain, Bhuvnesh; R,; Jedicke,; Jee, M James; Jernigan, J Garrett; Jha, Saurabh W; Johnston, Kathryn V; Jones, R Lynne; Juric, Mario; Kaasalainen, Mikko; Styliani,; Kafka,; Kahn, Steven M; Kaib, Nathan A; Kalirai, Jason; Kantor, Jeff; Kasliwal, Mansi M; Keeton, Charles R; Kessler, Richard; Knezevic, Zoran; Kowalski, Adam; Krabbendam, Victor L; Krughoff, K Simon; Kulkarni, Shrinivas; Kuhlman, Stephen; Lacy, Mark; Lepine, Sebastien; Liang, Ming; Lien, Amy; Lira, Paulina; Long, Knox S; Lorenz, Suzanne; Lotz, Jennifer M; Lupton, R H; Lutz, Julie; Macri, Lucas M; Mahabal, Ashish A; Mandelbaum, Rachel; Marshall, Phil; May, Morgan; McGehee, Peregrine M; Meadows, Brian T; Meert, Alan; Milani, Andrea; Miller, Christopher J; Miller, Michelle; Mills, David; Minniti, Dante; Monet, David; Mukadam, Anjum S; Nakar, Ehud; Neill, Douglas R; Newman, Jeffrey A; Nikolaev, Sergei; Nordby, Martin; O'Connor, Paul; Oguri, Masamune; Oliver, John; Olivier, Scot S; Olsen, Julia K; Olsen, Knut; Olszewski, Edward W; Oluseyi, Hakeem; Padilla, Nelson D; Parker, Alex; Pepper, Joshua; Peterson, John R; Petry, Catherine; Pinto, Philip A; Pizagno, James L; Popescu, Bogdan; Prsa, Andrej; Radcka, Veljko; Raddick, M Jordan; Rasmussen, Andrew; Rau, Arne; Rho, Jeonghee; Rhoads, James E; Richards, Gordon T; Ridgway, Stephen T; Robertson, Brant E; Roskar, Rok; Saha, Abhijit; Sarajedini, Ata; Scannapieco, Evan; Schalk, Terry; Schindler, Rafe; Schmidt, Samuel; Schmidt, Sarah; Schneider, Donald P; Schumacher, German; Scranton, Ryan; Sebag, Jacques; Seppala, Lynn G; Shemmer, Ohad; Simon, Joshua D; Sivertz, M; Smith, Howard A; Smith, J Allyn; Smith, Nathan; Spitz, Anna H; Stanford, Adam; Stassun, Keivan G; Strader, Jay; Strauss, Michael A; Stubbs, Christopher W; Sweeney, Donald W; Szalay, Alex; Szkody, Paula; Takada, Masahiro; Thorman, Paul; Trilling, David E; Trimble, Virginia; Tyson, Anthony; Van Berg, Richard; Berk, Daniel Vanden; VanderPlas, Jake; Verde, Licia; Vrsnak, Bojan; Walkowicz, Lucianne M; Wandelt, Benjamin D; Wang, Sheng; Wang, Yun; Warner, Michael; Wechsler, Risa H; West, Andrew A; Wiecha, Oliver; Williams, Benjamin F; Willman, Beth; Wittman, David; Wolff, Sidney C; Wood-Vasey, W Michael; Wozniak, Przemek; Young, Patrick; Zentner, Andrew; Zhan, Hu

    2009-01-01

    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable object...

  18. Fluence-to-effective dose conversion coefficients from a Saudi population based phantom for monoenergetic photon beams from 10 keV to 20 MeV

    Fluence-to-dose conversion coefficients are important quantities for radiation protection, derived from Monte Carlo simulations of the radiation particles through a stylised phantom or voxel based phantoms. The voxel phantoms have been developed for many ethnic groups for their accurate reflection of the anatomy. In this study, we used the Monte Carlo code MCNPX to calculate the photon fluence-to-effective dose conversion coefficients with a voxel phantom based on the Saudi Arabian male population. Six irradiation geometries, anterior–posterior (AP), posterior–anterior (PA), left lateral (LLAT), right lateral (RLAT), rotational (ROT) and isotropic (ISO) were simulated for monoenergetic photon beams from 10 keV to 20 MeV. We compared the coefficients with the reference values in ICRP Publication 116. The coefficients in the AP and PA geometries match the reference values to 9% and 12% on average as measured by root mean square while those in the LLAT, RLAT ROT and ISO geometries differ, mostly below, from the reference by 23, 22, 15 and 16%, respectively. The torso of the Saudi phantom is wider than the ICRP reference male phantom and likely to cause more attenuation to the lateral beam. The ICRP reference coefficients serve well for the Saudi male population as conservative estimations for the purpose of radiation protection. (paper)

  19. Toxic Substances Control Act Test Submissions 2.0 (TSCATS 2.0)

    U.S. Environmental Protection Agency — The Toxic Substances Control Act Test Submissions 2.0 (TSCATS 2.0) tracks the submissions of health and safety data submitted to the EPA either as required or...

  20. Trove: A Government 2.0 Showcase

    Holley, Rose

    2010-01-01

    The presentation demonstrates the features and development which have made Trove a Government 2.0 showcase. These include opening access to information, sharing and collaborating, involving users in development, and a high level of social engagement in the service.

  1. 30 CFR 20.2 - Definitions.

    2010-07-01

    ... MINING PRODUCTS ELECTRIC MINE LAMPS OTHER THAN STANDARD CAP LAMPS § 20.2 Definitions. (a) Adequate.... Official notification in writing from MSHA to a responsible organization, stating that upon...

  2. Biology Education Research 2.0

    Dolan, Erin L.

    2015-01-01

    Biology education research (BER) 2.0 has arrived, and is moving the BER community beyond showing that active learning works to understanding the individual and contextual factors that explain and influence biology teaching and learning.

  3. The Konstanz Information Miner 2.0

    Meinl, Thorsten; Cebron, Nicolas; Gabriel, Thomas R.; Dill, Fabian; Kötter, Tobias; Ohl, Peter; Thiel, Kilian; Wiswedel, Bernd; Berthold, Michael R

    2009-01-01

    In December 2008, version 2.0 of the data analysis platform KNIME was released. It includes several new features, which we will describe in this paper. We also provide a short introduction to KNIME for new users.

  4. Institutions Struggling with Web 2.0

    Drachsler, Hendrik; Hermans, Henry

    2008-01-01

    Drachsler, H., & Hermans, H. (2008). Institutions Struggling with Web 2.0 - Moving Between Personal and Managed Learning Environments. Presentation at Online Educa 2008. December, 4, 2008, Berlin, Germany.

  5. Lost in Web 2.0 Cyberspace?

    Fallon, Julia

    2008-01-01

    Web 1.0 never left. It's just a term that refers to cyberspace before 2002. People mark the shift from Web 1.0 to 2.0 with the dramatic collapse of Web-based companies whose phenomenal growth was based on the profit potential of a new customer: the Internet user. Generally, Web 1.0 sites have a commercial focus. On the other hand, Web 2.0 reverses…

  6. Ecodesign Directive version 2.0

    This present report reports on the main findings of the project Ecodesign Directive version 2.0 - from Energy Efficiency to Resource Efficiency. The project is financed by the Danish Environmental Protection Agency and ran from December 2012 to June 2014.......This present report reports on the main findings of the project Ecodesign Directive version 2.0 - from Energy Efficiency to Resource Efficiency. The project is financed by the Danish Environmental Protection Agency and ran from December 2012 to June 2014....

  7. First direct high-precision energy determination for the 8.4 and 20.7 keV nuclear transitions in Tm-169

    Inoyatov, A. K.; Kovalík, Alojz; Filosofov, D. V.; Ryšavý, Miloš; Perevoshchikov, L. L.; Gurov, Yu. B.

    2015-01-01

    Roč. 51, č. 6 (2015), s. 65. ISSN 1434-6001 R&D Projects: GA MŠk LG14004; GA ČR(CZ) GAP203/12/1896 Institutional support: RVO:61389005 Keywords : electron binding energies * internal conversion * Tc-99M Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.736, year: 2014

  8. Definition of Health 2.0 and Medicine 2.0: a systematic review.

    Belt, T. van den; Engelen, L.J.; Berben, S.A.A.; Schoonhoven, L.J.

    2010-01-01

    BACKGROUND: During the last decade, the Internet has become increasingly popular and is now an important part of our daily life. When new "Web 2.0" technologies are used in health care, the terms "Health 2.0" or "Medicine 2.0" may be used. OBJECTIVE: The objective was to identify unique definitions

  9. Best Practices of WEB 2.0

    G.N.K.Suresh Babu

    2013-03-01

    Full Text Available In this paper the author describes about what is Web 2.0, how It evolves from Web 1.0, differences between Web 1.0, 2.0 and 3.0 and how we can use Web 2.0 in best practice manner. The author analyses how Web 2.0 can be used in Web Personalization and site structure. There is considerable excitement about the notion of 'Web 2.0', particularly among Internet business people. In contrast, there is an almost complete lack of formal literature on the topic. It is important that movements with such energy and potential be subjected to critical attention, and that industry and social commentators have the opportunity to draw on the eCommerce research literature in formulating their views. The author assesses the available information about Web 2.0, with a view to stimulating further work that applies existing theories, proposes new ones, observes and measures phenomena, and tests the theories. The primary interpretation of the concept derives from marketers, but the complementary technical and communitarian perspectives are also considered. A common theme derived from the analysis is that of 'syndication' of content, advertising, storage, effort and identity.

  10. Interaction between Solid Nitrogen and 1-3-keV Electrons

    Schou, Jørgen; Sørensen, H.

    1978-01-01

    Experimental studies were made of the interaction between solid nitrogen and beams of 1-2-keV electrons. The projected range for the electrons was measured by means of the mirror-substrate method (gold substrate), giving the result 9.02×1016 E1.75 molecules/cm2 with the energy given in keV. The...... to fair...

  11. Study on Web 2.0%浅议Web 2.0

    周晓雨

    2010-01-01

    该文介绍了Web2.0的基本概念,Tim O'Reilly提出的规范定义Web2.0的七大准则以及Web2.0的技术,例如RSS,Mashup 和AJAX.与Web1.0相比,Web2.0提供了许多新功能.随着技术的发展,Web2.0技术被广泛应用,使用户获得更丰富的体验.

  12. Experimental study of interactions of highly charged ions with atoms at keV energies: Progress report for period January 16, 1988--February 20, 1989

    The Cornell superconducting solenoid, cryogenic electron beam ion source CEBIS II has been rebuilt around a commercial 3 Tesla superconducting solenoid manufactured by Nicolet Instrument Corporation of Madison, WI. This solenoid has very low cryogen consumption which allows us to operate it continuously in the persistent current mode. Preliminary test with a 4.5 kV, 0.08 A electron beam show 100% transmission from cathode through the main magnetic field at 3 Tesla. The source is ready for gas and ion injection tests and experiments. An external sputter PIG ion source capable of supplying singly charged ions of elements other than noble gases has been tested, and several microampere beams of aluminum and lead ions have been produced. A Wien filter and an ion beam line with focusing optics have been designed and built and are in the process of being tested. A number of experiments utilizing our smaller, conventional solenoid EBIS, CEBIS I are in progress. These include the study of ion heating in an EBIS, a study of photon emissions from highly charged ions impinging on metal surfaces and the investigation of one and several electron capture via small angle scattering of highly charged projectiles from helium at 0.1 to 0.5 keV/amu. 2 refs., 10 figs

  13. The solar wind charge-transfer X-ray emission in the 1/4 keV energy range: inferences on Local Bubble hot gas at low Z

    Koutroumpa, D; Raymond, J C; Kharchenko, V

    2008-01-01

    We present calculations of the heliospheric SWCX emission spectra and their contributions in the ROSAT 1/4 keV band. We compare our results with the soft X-ray diffuse background (SXRB) emission detected in front of 378 identified shadowing regions during the ROSAT All-Sky Survey (Snowden et al. 2000). This foreground component is principally attributed to the hot gas of the so-called Local Bubble (LB), an irregularly shaped cavity of ~50-150 pc around the Sun, which is supposed to contain ~10^6 K plasma. Our results suggest that the SWCX emission from the heliosphere is bright enough to account for most of the foreground emission towards the majority of low galactic latitude directions, where the LB is the least extended. In a large part of directions with galactic latitude above 30deg the heliospheric SWCX intensity is significantly smaller than the measured one. However, the SWCX R2/R1 band ratio differs slightly from the data in the galactic center direction, and more significantly in the galactic anti-ce...

  14. Preliminary measurements of doubly differential cross sections for ejection of electrons from atomic hydrogen by 70 keV protons

    A Slevin atomic hydrogen source has been used to produce a thermal beam of H and H2 as a target for 70 keV protons. A method has been devised which yields atomic to molecular hydrogen cross section ratios. Since the electron ejection cross sections for H2 are known, the atomic hydrogen cross sections can be determined. The angular and energy ranges of the detected electrons, differential in angle and energy, are 20 degrees-160 degrees and 1.5-250 eV respectively

  15. Preliminary measurements of doubly differential cross sections for ejection of electrons from atomic hydrogen by 70 keV protons

    Kerby, G.W.; Gealy, M.W.; Hsu, Y.Y.; Rudd, M.E. [Univ. of Nebraska, Lincoln, NB (United States)

    1993-05-01

    A Slevin atomic hydrogen source has been used to produce a thermal beam of H and H{sub 2} as a target for 70 keV protons. A method has been devised which yields atomic to molecular hydrogen cross section ratios. Since the electron ejection cross sections for H{sub 2} are known, the atomic hydrogen cross sections can be determined. The angular and energy ranges of the detected electrons, differential in angle and energy, are 20{degrees}-160{degrees} and 1.5-250 eV respectively.

  16. An accuracy assessment of photo-ionization cross-section datasets for 1–2 keV x-rays in light elements using PIXE

    Proton-induced x-ray emission (PIXE) was used to assess the accuracy of the National Institute of Standards and Technology XCOM and FFAST photo-ionization cross-section databases in the low energy region (1–2 keV) for light elements. Characteristic x-ray yields generated in thick samples of Mg, Al and Si in elemental and oxide form, were compared to fundamental parameters computations of the expected x-ray yields; the database for this computation included XCOM attenuation coefficients. The resultant PIXE instrumental efficiency constant was found to differ by 4–6% between each element and its oxide. This discrepancy was traced to use of the XCOM Hartree–Slater photo-electric cross-sections. Substitution of the FFAST Hartree–Slater cross-sections reduced the effect. This suggests that for 1–2 keV x-rays in light element absorbers, the FFAST predictions of the photo-electric cross-sections are more accurate than the XCOM values. (paper)

  17. Web 2.0失败

    2005-01-01

    “自以为自己在做Web 2.0的人,拿着商业计划书去找投资商的那群人,在我看来90%说的不是Web 2.0,这是第一个90%;第二个90%是,现在一腔热血立志要做Web2.0的人,他们之中90%的人没有做过,或是没有做好过Web1.0,我们看到一批热血青年,让我感觉自己仿佛回到了1999年;第三个90%是现在风险投资、实业投资投的所谓Web2.0的项目,90%是投错了。”和讯网CEO谢文很直白的讲述着他对国内Web 2.0现状的看法。

  18. 20 CFR 615.2 - Definitions.

    2010-04-01

    ... employment, for the purposes of section 202(a)(4) of the Act, means service performed in an employer-employee... search activity throughout the given week, compatible with the number of employers and employment... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Definitions. 615.2 Section 615.2...

  19. Electron inelastic interactions in bioorganic compounds in the energy range of 20 10000 eV

    Tan, Z.; Xia, Y.; Liu, X.; Zhao, M.; Ji, Y.; Li, F.; Huang, B.

    2005-09-01

    Systematic calculations of stopping powers (SPs) and mean free paths (MFPs) for 10 bioorganic compounds have been performed for electrons with energies lower than 10 keV, based on dielectric response theory and Penn’s statistical approximation. The exchange effect is also taken into account in the calculations. An empirical approach to obtain an optical energy loss function is presented for those organic compounds without available optical data. Using this method, the calculated values of the optical energy loss function are in good agreement with experimental data. Comparisons of SP and MFP values derived in this study with other published values are presented. Using the described model, the calculated mean ionization potentials agree well with the predictions from Bragg’s rule and the calculated SPs have also been compared with the Bethe Bloch results at an energy of 10 keV.

  20. 50 CFR 30.2 - Disposition of surplus range animals.

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Disposition of surplus range animals. 30.2... (CONTINUED) THE NATIONAL WILDLIFE REFUGE SYSTEM RANGE AND FERAL ANIMAL MANAGEMENT Range Animals § 30.2 Disposition of surplus range animals. Disposition shall be made only during regularly scheduled...

  1. Learning 2.0 : concepts and experiences

    Huertas Sánchez, Maria Antònia

    2007-01-01

    E-learning arises in all educative contexts and levels with the use of information and communication technologies and massive access to internet connected computers. On the other hand, the fast development of social networking tools and web 2.0 technologies are producing an evolution of e-learning towards what is called a learning 2.0 paradigm. In this short paper we shall present the main technologies and pedagogical issues related to that new way of learning and how we can use them to im...

  2. WeighTrack 2.0

    Kugler, Tyler Reed

    2015-01-01

    In the growing field of the Internet of Things, the interactions with our surrounding environments are growing smarter and more reliant on data collection and analytics. WeighTrack 2.0 adds intelligence to liquid inventories, allowing users to precisely monitor the amount of liquid content in a bottle at any given time, without directly interacting with the fluid. Through the implementation of RFID technology, load-cell networks, and a Wi-Fi-enabled micro-controller, WeighTrack 2.0 provides a...

  3. Web 2.0 for IPTV

    Leung, Simon; Pettersson, Johan

    2008-01-01

    This master’s thesis project concerns implementing and evaluating Web 2.0 services for IPTV. This thesis project was carried out at Accedo Broadband during the period August to December 2008. Accedo Broadband is a provider of interactive applications and on-demand content for IPTV. The report will analyze, specify, create, and evaluate a solution for adding Web 2.0 functionality from the most popular sites as IPTV content. We will evaluate several different web services APIs and examine how s...

  4. How web 2.0 helps crowdfunding

    Mourisco, Pedro Miguel Matos Pinheiro Dias

    2016-01-01

    This study establishes a bridge between Web 2.0 and Crowdfunding. It shows that there is a relation between creation of content and the money collected, using a dataset of campaigns from the Kickstarter platform. Besides this, the study explores the comprehension of the society to these matters. A survey was made in a Higher Education Institution to evaluate if there is an awareness of the society to matters such as crowdfunding and Web 2.0. The study started with a literature review that ...

  5. Fabrication critique et web 2.0

    COOK et al, Ian

    2016-01-01

    Des lecteurs reprochent actuellement aux études portant sur les nouveaux médias de n’accorder que peu d’intérêt aux injustices sociales et environnementales liées aux infrastructures techniques du web 2.0. Pourtant, dans le même temps, des chercheurs qui s’intéressent aux questions de justice sociale et environnementale font usage du web 2.0 pour conduire leurs expérimentations, et utilisent les wikis, les blogs, twitter et les réseaux sociaux pour développer et diffuser leurs recherches. C’e...

  6. World Wide Web Astronomy 2.0

    Koppelman, M.; Gay, P. L.

    2008-11-01

    The Internet has changed astronomy. It's changed research, outreach and education and it's changed how people consume astronomy as enthusiasts. People have new ways to talk to each other and new ways to participate. Coined ``Web 2.0,'' technologies such as blogs, social networks, wikis, photo and video sharing sites, podcasts and micro-blogging have been adopted by the astronomy community and exciting things are happening as a result. The International Year of Astronomy's New Media Task Force has been working to harness the excitement of ``Web 2.0'' to make the International Year of Astronomy (IYA2009) highly visible on the Internet around the world.

  7. WAITING FOR WEB 2.0

    2006-01-01

    What will the next generation of Internet services mean for China? The Web 2.0 buzzword, having gathered speed in the United States in recent years as a way to describe new, more collaborative Internet applications, is attracting the attention and money of a batch of Chinese start-up firms. But will it attract the people? Late last year, the China Internet Society released a report that tracked this second major round of Internet boom. The findings of the report, titled China Web 2.0

  8. Cyberpunk 2.0: fiction and contemporary

    Elias, Herlander

    2009-01-01

    I first published this book in 1999, a few months before the The Matrix motion picture was released. This was my first book, and there’s no other like our first one. So in the past decade I have been updating this Cyberpunk 2.0: Fiction And Contemporary. And instead of seeing it turning obsolete I witnessed it become very real, present and obvious. This Second edition of Cyberpunk 2.0: Fiction And Contemporary is about the “reloading matrix” of media, how videoclip culture globalized itse...

  9. New observations for the triggering of 178m2Hf isomer embedded in Ta matrix by 30 keV electrons

    178m2Hf isomer triggering has been studied using the upgraded experimental setup developed in Kharkiv National University and installed at Kyiv Institute for Nuclear Research. The target that presented a single Ta foil of 300 μm thickness with 178m2Hf isomeric activity of about 100 Bq has been irradiated by 30 keV electron beam. The enhanced counting rates of all the ground-state band transitions have been observed. Our data are consistent with an estimate for the triggering effect of 2.9 ±0.7 % and the electron induced triggering cross-section can be estimated as 1.1 b, which is about four times less than the upper limit for the photon induced triggering cross-section 4.7 b

  10. Interaction between solid nitrogen and 1--3-keV electrons

    Experimental studies were made of the interaction between solid nitrogen and beams of 1--3-keV electrons. The projected range for the electrons was measured by means of the mirror-substrate method (gold substrate), giving the result 9.02 x 1016 E/sup 1.75/ molecules/cm2 with the energy given in keV. The escape depth for secondary electrons was studied by means of the equivalent-substrate method (carbon substrate). The results varied from 280 A at 1 keV to 400 A at 3 keV. Measurements were also made of the secondary-electron-emission coefficient, which varied from 2.3 el/el at 1 keV to 1.2 el/el at 3 keV. At 3 keV, the SEE coefficient is 12 times that for solid deuterium. This is attributed partly to the larger production rate for low-energy electrons in nitrogen and partly to the larger escape probability for these electrons. Moreover, measurements were made of the electron-reflection coefficient, both for solid nitrogen and for the carbon substrate. For nitrogen, it varied from 0.17 el/el at 1 keV to 0.13 el/el at 3 keV, and for carbon it varied from 0.13 to 0.12. The observations are discussed and comparisons made with other theoretical and experimental results. The agreement ranges from good to fair

  11. Herwig++ 2.0beta Release Note

    Gieseke, Stefan; Grellscheid, D.; Ribon, Alberto; Richardson, P.; Seymour, Michael H.; Stephens, Phil; Webber, Bryan R

    2006-01-01

    A new release of the Monte Carlo program Herwig++ (version 2.0beta) is now available. The main new feature is the extension of the program to include simple hadron-hadron processes including the initial-state parton shower.

  12. Change Management Meets Web 2.0

    Gale, Doug

    2008-01-01

    Web 2.0 is the term used to describe a group of web-based creativity, information-sharing, and collaboration tools including wikis, blogs, social networks, and folksonomies. The common thread in all of these tools is twofold: They enable collaboration and information sharing, and their impact on higher education has been dramatic. A recent study…

  13. Integrated Pest Management 2.0

    Boonekamp, P. M.

    2013-01-01

    IPM 2.0 – Towards future-proof crop protection in Europe was een groot success. Het congres dat begin oktober 2012 in Wageningen werd gehouden was het tiende congres van de European Foundation for Plant Pathology (EFPP) en werd georganiseerd door de KNPV.

  14. The PLATO 2.0 mission

    H. Rauer; al et; S. Hekker

    2014-01-01

    PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets

  15. Becoming Teacher-Librarian 2.0

    Anita Mary Brooks Kirkland

    2007-05-01

    Full Text Available This article discusses the place of Web 2.0 social software in the school library program. It examines the potential of this technology for enhancing teaching and learning, and the implications for students' information literacy. The article suggests ways for teacher-librarians to engage in professional learning to increase their knowledge of this evolving field.

  16. Calculations of total ionization cross sections for halogen compounds on electron impact from threshold to 2 keV

    Calculation for electron impact total ionization cross sections on halogen compounds (BF, SiF, BCI, SiCl) are performed employing Spherical Complex Optical Potential and Complex Optical Potential - ionization contribution (CSP-ic) formalisms. In this article we are presenting data for energies ranging from above threshold to 2000 eV. Our results are compared with available experimental and theoretical data wherever available. It is found that the present result gives a better account of the ionization cross sections. (author)

  17. Using Web 2.0 for Learning in the Community

    Mason, Robin; Rennie, Frank

    2007-01-01

    This paper describes the use of a range of Web 2.0 technologies to support the development of community for a newly formed Land Trust on the Isle of Lewis, in NW Scotland. The application of social networking tools in text, audio and video has several purposes: informal learning about the area to increase tourism, community interaction,…

  18. Calculation of Multisphere Neutron Spectrometer Response Functions in Energy Range up to 20 MeV

    Martinkovic, J

    2005-01-01

    Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, "bare" detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10$^{-8}$-20 MeV.

  19. Calculation of multisphere neutron spectrometer response functions in energy range up to 20 MeV

    Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, 'bare' detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10-8 - 20 MeV

  20. Theoretical Study of Secondary Electron Yield in Energy Range of 10 ~ 30 keV%10~30 keV二次电子发射系数的表达式

    谢爱根; 王祖松; 刘战辉; 詹煜; 吴红艳

    2013-01-01

    Here we addressed the theoretical subject of the secondary electron emission,in the energy range of 10 ~30keY.First,the formulae of the maximum second electron yield (δm),and the average number of secondary electrons released per primary electron with fairly high incident energy (δPE) were derived,respectively.Next,a general expression of δ in terms of the variables,including δm,atomic number,atomic weight,material density,back-scattering coefficient (γ),back-scattering coefficient at high energy (η),parameter A,energy exponent (n),and the incident energy of primary electron,was obtained,on the basis of the influence of δm and δPE on the secondary electron yield at high energy (δ).The parameter A and energy exponent n,in the energy range of 10 ~ 30 keV for some emitters of interest,were modeled and calculated with the software package ESTAR.The experimentally measured and calculated results of δ with the general formula were compared.The comparison result shows that when it comes to the secondary electron emission in the energy range of 10~ 30 keV,the newly-developed general formula of δ works fairly well for metals,semi-metals and element semiconductors.%根据二次电子发射的主要物理过程和特性,推导出最大二次电子发射系数(δm)的表达式.还推导出平均每个高能原电子发射的二次电子数(δPE)的表达式.根据δPE、δm和高能二次电子发射系数(δ)之间的关系,推导出以δm、原子序数、原子质量数、物质密度、背散射系数、高能背散射系数、参数A、能量幂次(n)和原电子入射能量为变量δ的通式.用ESTR程序计算出一些材料的10~ 30 keV能量范围内的参数A和n.用该通式计算出δ并与相应的实验值进行了比较,结果表明,成功地推导出金属、半金属和元素半导体10~ 30 keV的δ通式.

  1. X-ray detection with Micromegas with background levels below 10$^{-6}$ keV$^{-1}$cm$^{-2}$s$^{-1}$

    Aune, S; Calvet, D.; Dafni, T.; Diago, A.; Druillole, F.; Fanourakis, G.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Gardikiotis, A.; Garza, J.G.; Geralis, T.; Giomataris, I.; Gómez, H.; González-Díaz, D.; Herrera, D.C.; Iguaz, F.J.; Irastorza, I.G.; Jourde, D.; Luzón, G.; Mirallas, H.; Mols, J.P.; Papaevangelou, T.; Rodríguez, A.; Seguí, L.; Tomás, A.; Vafeiadis, T.; Yildiz, S.C.

    2013-01-01

    Micromegas detectors are an optimum technological choice for the detection of low energy x-rays. The low background techniques applied to these detectors yielded remarkable background reductions over the years, being the CAST experiment beneficiary of these developments. In this document we report on the latest upgrades towards further background reductions and better understanding of the detectors' response. The upgrades encompass the readout electronics, a new detector design and the implementation of a more efficient cosmic muon veto system. Background levels below 10$^{-6}$keV$^{-1}$cm$^{-2}$s$^{-1}$ have been obtained at sea level for the first time, demonstrating the feasibility of the expectations posed by IAXO, the next generation axion helioscope. Some results obtained with a set of measurements conducted in the x-ray beam of the CAST Detector Laboratory will be also presented and discussed.

  2. Discussing the physical meaning of the absorption feature at 2.1 keV in 4U 1538-52

    Rodes-Roca, J J; Mart\\'\\inez-Núñez, S; Giménez-Garc\\'\\ia, A; Bernabéu, G

    2014-01-01

    High resolution X-ray spectroscopy is a powerful tool for studying the nature of the matter surrounding the neutron star in X-ray binaries and its interaction between the stellar wind and the compact object. In particular, absorption features in their spectra could reveal the presence of atmospheres of the neutron star or their magnetic field strength. Here we present an investigation of the absorption feature at 2.1 keV in the X-ray spectrum of the high mass X-ray binary 4U 1538-52 based on our previous analysis of the XMM-Newton data. We study various possible origins and discuss the different physical scenarios in order to explain this feature. A likely interpretation is that the feature is associated with atomic transitions in an O/Ne neutron star atmosphere or of hydrogen and helium like Fe or Si ions formed in the stellar wind of the donor.

  3. Guiding of 150 keV O6+ ions through nanocapillaries in an uncoated Al2O3 membrane: special time dependence of the transmission profile width

    Chen Xi-Meng; Xi Fa-Yuan; Qiu Xi-Yu; Shao Jian-Xiong; Xiao Guo-Qing; Cui Ying; Sun Guang-Zhi; Wang Jun; Chen Yi-Feng; Liu Hui-Ping; Yin Yong-Zhi; Wang Yu-Yu; Li De-Hui; Lou Feng-Jun; Wang Xing-An; Xu Jun-Kui; Zhou Chun-Lin

    2009-01-01

    This paper reports that the transmission of O6+ ions with energy of 150keV through capillaries in an uncoated Al2O3 membrane was measured, and agreements with previously reported results in general angular distribution of the transmitted ions and the transmission fractions as a function of the tilt angle well fitted to Gaussian-like functions were observed. Due to using an uncoated capillary membrane, our ψc is larger than that using a gold-coated one with a smaller value of Ep/q, which suggests a larger equilibrium charge Q∞ in our experiment. The observed special width variation with time and a larger width than that using a smaller Ep/q were qualitatively explained by using mean-field classical transport theory based on a classical-trajectory Monte Carlo simulation.

  4. Flat Crystal x-ray Spectrometer for Quantitative Spectral Measurement in the 2-5 keV Region

    ZHAO Yang; ZHANG Ji-Yan; YANG Jia-Min; WEI Min-Xi; DENG Bo; ZHU Tuo; HU Zhi-Min; XIONG Gang; SHANG Wan-Li; KUANG Long-Yu; YANG Guo-Hong

    2011-01-01

    @@ A technique of fiat crystal x-ray spectrometer for quantitative spectral measurement is described.For the flat crystal spectrograph geometry, the quantitative reduction of relating the CCD counts back to the photon flux from the x-ray source is established.The absolute calibrations of the integral diffraction coefficients of the crystal and the CCD sensitivity make it possible to measure absolute photons flux within the energy range of 2000-5000 eV.The uncertainty analysis of the calibrations is carried out to obtain the energy resolved uncertainties of crystal and CCD.Thus, the experimentai spectra with spectral resolved intensity uncertainties are available.Then, a performing experiment of laser-produced Ti plasma is carried out and the absolute x-ray spectra with intensity uncertainty less than 8.5% are obtained.The technique is promising for absolute spectral measurement of high temperature plasmas in a kilo-electron-volt region.

  5. Bibliotecas escolares e web 2.0

    Cassia Cordeiro Furtado

    2009-12-01

    Full Text Available O artigo enfoca o papel da educação e da biblioteca na Sociedade da Informação e apresenta conceitos e características da Biblioteca 2.0 (L2. Defende o uso da web 2.0, na biblioteca escolar, visando otimizar ou criar serviços e produtos, para fins de conquista dos usuários, visibilidade e espaço na escola e na sociedade. Identifica nos programas públicos de incentivo e implantação de bibliotecas nas escolas, no Brasil e em Portugal, a presença ou recomendações para o uso da web 2.0. Com base na literatura conclui que, em Portugal, já ocorre a iniciativa do uso dos blogs por parte da biblioteca escolar, porém com escassez de comentários por parte do usuário. E que as bibliotecas brasileiras têm um longo caminho a percorrer no que tange as bibliotecas escolares, como também no contexto dos sistemas de informação.

  6. PCXMC 2.0. User's Guide

    PCXMC is a computer program for calculating patients' organ doses and the effective dose in medical x-ray examinations. It allows a free adjustment of the x-ray projection and other examination conditions of projection radiography and fluoroscopy. The anatomical data are based on the mathematical hermaphrodite phantom models of Cristy and Eckerman (1987), with some modifications and user-adjustable phantom sizes. The program also calculates the risk of death for radiation-induced cancers. This User's Manual explains how to use the program (version 2.0). The technical documentation of the program is published in report STUK-A231, which describes the concepts, methods and data used in PCXMC 2.0. (orig.)

  7. The $(2,0)$ superconformal bootstrap

    Beem, Christopher; Rastelli, Leonardo; van Rees, Balt C

    2016-01-01

    We develop the conformal bootstrap program for six-dimensional conformal field theories with $(2,0)$ supersymmetry, focusing on the universal four-point function of stress tensor multiplets. We review the solution of the superconformal Ward identities and describe the superconformal block decomposition of this correlator. We apply numerical bootstrap techniques to derive bounds on OPE coefficients and scaling dimensions from the constraints of crossing symmetry and unitarity. We also derive analytic results for the large spin spectrum using the lightcone expansion of the crossing equation. Our principal result is strong evidence that the $A_1$ theory realizes the minimal allowed central charge $(c=25)$ for any interacting $(2,0)$ theory. This implies that the full stress tensor four-point function of the $A_1$ theory is the unique unitary solution to the crossing symmetry equation at $c=25$. For this theory, we estimate the scaling dimensions of the lightest unprotected operators appearing in the stress tenso...

  8. Web 2.0烧钱

    2005-01-01

    在中国,但凡参加一次有关Web 2.0的研讨会,你首先要做出两种选择:一个是带足100张名片,因为那里有太多的网络精英,有太多新的面孔。另一个选择是你可以一张名片都不带,因为那里有太多的空想者,“凭借一个想法,就想融到百万美元投资的人比比皆是”。Web 2.0的聚会有时候对于创业者来说更像一场幻梦。

  9. Study of the collisional destruction of neutral hydrogen atoms in the ground state H(12S) and in the metastable state H(22S) on different rare gas targets in the 0.5 to 3.0 keV level energy range

    The total destruction cross-sections of H(22S) on rare gases and hydrogen are studied in the energy range 50 to 3000 eV, and the electron loss and electron capture cross-sections from H(12S) and H(22S) in the energy range 0.5 to 3 keV. The de-excitation cross-sections are deduced

  10. HOPE aggregator infrastructure release 2.0

    Bardi, Alessia; Zoppi, Franco

    2012-01-01

    This document describes the implementation of the HOPE Aggregator Infrastructure in terms of: . Core Functionalities . Software Tools for Quality Control and Metadata Enrichment . HW & SW requirements After an introduction to the general characteristics of the HOPE implementation, the functionalities offered by this Release 2.0 are presented. Then, the characteristics of the software tools available for Aggregator Administration and Data Curation are introduced. A further section reports the ...

  11. Isomer shifts of the 6.2-keV gamma-rays of tantalum-181. Chapter 8d

    The present chapter is divided into two main parts. In the first part, the more general aspects of 181Ta isomer shifts are covered, including an estimation of Δ(r2) from the systematics of isomer shifts in transition metal hosts. The second part is devoted to solid-state applications, such as studies of the isomer-shift dependence on hydrostatic pressure, on temperature, and on impurity atoms, especially hydrogen. (Auth.)

  12. LSST Science Book, Version 2.0

    LSST Science Collaboration; Abell, Paul A.; Allison, Julius; Anderson, Scott F.; Andrew, John R.; Angel, J. Roger P.; Armus, Lee; Arnett, David; Asztalos, S. J.; Axelrod, Tim S.; Bailey, Stephen; Ballantyne, D. R.; Bankert, Justin R.; Barkhouse, Wayne A.; Barr, Jeffrey D.

    2009-01-01

    A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad band...

  13. Small-sized accelerating tube for electron acceleration to 500 keV at pulse duration of 2 ns

    The design and characteristics (current, voltage, current density, electron beam structure, energy spectrum, and dose rate) of a soldered small-size two-electrode 600 kV accelerating tube are considered. A six-stage Arkadiev-Marx generator is the pulse high-voltage supply of nanosecond duration. When using a cathode (diameter of 8 mm) made of tantalum foil 0.02 mm thick and with interelectrode gap of 10 mm, the amplitude of the electron beam current beyond the beryllium anode equals to 1040 A under maximum voltage of 490 kV, current pulse duration of 2 ns, number of electrons is 1013. The increased electron density on the anode in a spot of 4 mm in diameter is observed; the current density in the spot reaches 1 kA/cm2. The electron energy in the beam beyond the anode is as much as 0.6-0.8 J per pulse, and the dose rate near the outer surface of the outlet window is 1014-1015 rad/s. The use of an intensifying oil spark gap is shown to increase radiation hardness. The accelerating tube provides more than 105 shots in a single-switching mode

  14. r-Java 2.0: the nuclear physics

    Kostka, M.; N. Koning; Shand, Z.; Ouyed, R.; Jaikumar, P.

    2014-01-01

    [Aims:] We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations as well as a suite of other analysis tools. [Methods:] Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of; simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission as well as the study of individual nucle...

  15. Evaluation of 242Pu data for the incident neutron energy range 5-20 MeV

    Models, procedures and parameters are presented for the calculation of neutron cross sections, the neutron angular distributions and the neutron energy distributions of 242Pu in the energy range 5-20 MeV. The interaction takes place through direct interaction and compound nucleus mechanism. For heavy deformed nucleus the direct interaction was treated with the coupled channel process, using the ECIS code. For the compound nucleus mechanism, a statistical treatment was used for fission, neutron elastic and inelastic scattering, radiative capture, (n,2n), (n,3n), (n,4n) cross section calculations, using the GNASH code. (R.P.)

  16. A calculation on n-D scattering cross sections in the energy range 0 to 20 MeV

    A calculation on n-D scattering cross sections with phase shift analysis is carried out in the neutron energy range of 0 to 20 MeV. An optimum set of parameters are obtained by fitting the experimental data which include total, (n,2n) and differential cross section of n-D scattering. The comparisons were made between this calculated results and previous works. It was showed that the obtained differential elastic cross sections are in good agreement with the experimental values

  17. Efficient focusing of 8 keV X-rays with multilayer Fresnel zone plates fabricated by atomic layer deposition and focused ion beam milling

    The fabrication and performance of multilayer Al2O3/Ta2O5 Fresnel zone plates in the hard X-ray range and a discussion of possible future developments considering available materials are reported. Fresnel zone plates (FZPs) recently showed significant improvement by focusing soft X-rays down to ∼10 nm. In contrast to soft X-rays, generally a very high aspect ratio FZP is needed for efficient focusing of hard X-rays. Therefore, FZPs had limited success in the hard X-ray range owing to difficulties of manufacturing high-aspect-ratio zone plates using conventional techniques. Here, employing a method of fabrication based on atomic layer deposition (ALD) and focused ion beam (FIB) milling, FZPs with very high aspect ratios were prepared. Such multilayer FZPs with outermost zone widths of 10 and 35 nm and aspect ratios of up to 243 were tested for their focusing properties at 8 keV and shown to focus hard X-rays efficiently. This success was enabled by the outstanding layer quality thanks to ALD. Via the use of FIB for slicing the multilayer structures, desired aspect ratios could be obtained by precisely controlling the thickness. Experimental diffraction efficiencies of multilayer FZPs fabricated via this combination reached up to 15.58% at 8 keV. In addition, scanning transmission X-ray microscopy experiments at 1.5 keV were carried out using one of the multilayer FZPs and resolved a 60 nm feature size. Finally, the prospective of different material combinations with various outermost zone widths at 8 and 17 keV is discussed in the light of the coupled wave theory and the thin-grating approximation. Al2O3/Ir is outlined as a promising future material candidate for extremely high resolution with a theoretical efficiency of more than 20% for as small an outermost zone width as 10 nm at 17 keV

  18. Library 2.0 Theory: Web 2.0 and Its Implications for Libraries

    Jack M. Maness

    2006-06-01

    Full Text Available This article posits a definition and theory for "Library 2.0". It suggests that recent thinking describing the changing Web as "Web 2.0" will have substantial implications for libraries, and recognizes that while these implications keep very close to the history and mission of libraries, they still necessitate a new paradigm for librarianship. The paper applies the theory and definition to the practice of librarianship, specifically addressing how Web 2.0 technologies such as synchronous messaging and streaming media, blogs, wikis, social networks, tagging, RSS feeds, and mashups might intimate changes in how libraries provide access to their collections and user support for that access.

  19. Metrological characterization of optical confocal sensors measurements (20 and 350 travel ranges)

    Confocal sensors are usually used in dimensional metrology applications, like roughness, form, thickness and surface profile measurements. With the progress of technologies, metrological applications require measurements with nanometer-level of accuracy by using ultra-high precision machines, which should present a minimum and stable metrology loop. The loop is equipped with sensors with nanometer-level of resolution and linear residual. The study presented here, is mainly focused on the characterization of Confocal sensors in order to identify their performance practically. Such information is useful to establish a correction model in the digital signal processing (DSP) software. In this context, LNE developed an ultra-high-precision machine, dedicated to the roughness measurement with an uncertainty of a few nanometres (< 30 nm) by using a tactile sensor. In order to match this machine to Confocal sensors, an experiment has been recently developed to characterize the behaviour of two commercial Confocal sensors with the measuring range of 20 μm and 350 μ m. The experiment permits the evaluation of the major error sources: axial and radial motion errors as-well-as the deviation/tilt of the sensors

  20. Synthesis and magnetic properties of octahedral magnetite nanoparticles in 20–110 nm range

    Octahedral magnetite (Fe3O4) nanoparticles (NPs) with dimensions ranging from 20 to 110 nm are prepared via the decomposition of iron oleate complex in the presence of cetyltrimethylammonium bromide (CTAB) and various organic solvents. It is shown that the addition of an optimal amount of CTAB prompts the growth of equi-dimensional octahedral NPs with dominant {111} facets. Moreover, it is shown that the size of the octahedral NPs can be controlled by adjusting the relative amounts of oleic acid and CTAB and choosing an appropriate high-boiling point organic solvent. The X-ray diffraction analysis results reveal that the compositions of the as-synthesized NPs are solvent-dependent and contain different amounts of iron metal, wüstite and magnetite phases. The as-synthesized NPs are oxidized to pure magnetite via an air treatment and the room-temperature magnetic properties of the resulting products are then characterized by means of a superconducting quantum interference device. The results indicate that the superparamagnetic limit for the current magnetite NPs is equal to approximately 33.3 nm at a temperature of 300 K.Graphical Abstract

  1. The structural behavior of SrTiO{sub 3} under 400 keV Ne{sup 2+} ion irradiation

    Su, X.; Liu, C.G.; Yang, D.Y.; Wen, J.; Chen, L.J.; Xu, D.P.; Li, Y.H. [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Fu, E.G. [Peking University, State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Zhang, J. [Xiamen University, School of Energy Research, Xiamen (China); Wang, Y.Q. [Los Alamos National Laboratory, Materials Science and Technology Division, Los Alamos, NM (United States)

    2015-11-15

    The structural behavior of polycrystalline perovskite SrTiO{sub 3} under 400 keV Ne{sup 2+} ion irradiation at both liquid nitrogen (LN{sub 2}) and room temperature (RT) has been investigated. The grazing incident X-ray diffraction technique was applied to examine the radiation-induced structural evolution. The radiation behavior of SrTiO{sub 3} depends strongly on the irradiation temperature. At LN{sub 2} temperature, the samples exhibit significant lattice swelling and amorphization, whereas at RT, the lattice swelling is much less conspicuous and no amorphization is detected even at the highest irradiation dose of 5.0 dpa. Nevertheless, Ne{sup 2+} irradiation induces peak splitting in XRD patterns at both temperatures. Furthermore, first-principle calculations have been performed with VASP, involving possible defect types, to identify which defect is responsible for the radiation effect of SrTiO{sub 3}. The results reveal that the oxygen vacancy defect is the most likely to contribute to the radiation behavior of SrTiO{sub 3}. (orig.)

  2. [Gastroenterology 2.0: useful resources for the gastroenterologist available on the Web 2.0].

    Curioso, Walter H; Proaño, Alvaro; Ruiz, Eloy F

    2011-01-01

    The term Web 2.0 refers to the use of Internet applications which enable the users to share, participate and collaborate together on information. The objective of this study is to check different applications that use Web 2.0, which could help the gastroenterologist in his daily practice. The applications that will be checked include: blogs, microblogging, RSS, podcasts, wikis and social networks. "Gastroenterology 2.0" represents the applications, services, and tools based on Web 2.0, which are of easy use and easily accessible - to consumers, patients, gastroenterologists and other health professionals, as well as researchers. Although several studies have shown the benefits these technologies have on the medical practice, it is necessary to conduct further studies to demonstrate the use of these applications on improving health. PMID:22086320

  3. Web 2.0 and Higher Education

    Cunha, Luís António Morão Pinto Simões da

    2012-01-01

    Tese apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Doutor em Ciências da Informação, especialização em Sistemas e Tecnologias da Informação. The emergence of tools like Blogs or Wikis made the creation of online contents much easier than before. The evolving concept of Web 2.0 emphasizes the fact that the user can now easily participate in the delivery of Web contents, taking advantage of existing tools. In this thesis, two empirical stud...

  4. LA WEB 2.0 EN ESCENA.

    Raúl Santiago Campión; Fermín Navaridas Nalda

    2012-01-01

    En este artículo pretendemos desarrollar un análisis crítico sobre los denominados entornos Web 2.0. Para ello comenzaremos un recorrido "histórico" sobre el origen del término para después realizar una descripción de sus características, lo que nos permitirá abordar su funcionamiento técnico. Todo ello nos debe servir para tratar de comprender si nos encaminamos hacia el denominado modelo "3.0". Concluiremos con una crítica constructiva de algunos aspectos relevantes que se han venido mencio...

  5. La web 2.0 en escena

    Santiago Campión, Raúl; Fermín NAVARIDAS NALDA

    2012-01-01

    En este artículo pretendemos desarrollar un análisis crítico sobre los denominados entornos Web 2.0. Para ello comenzaremos un recorrido "histórico" sobre el origen del término para después realizar una descripción de sus características, lo que nos permitirá abordar su funcionamiento técnico. Todo ello nos debe servir para tratar de comprender si nos encaminamos hacia el denominado modelo "3.0". Concluiremos con una crítica constructiva de algunos aspectos relevantes que se han venido mencio...

  6. UQTk version 2.0 user manual.

    Debusschere, Bert J.; Sargsyan, Khachik; Safta, Cosmin

    2013-10-01

    The UQ Toolkit (UQTk) is a collection of libraries and tools for the quanti cation of uncer- tainty in numerical model predictions. Version 2.0 o ers intrusive and non-intrusive methods for propagating input uncertainties through computational models, tools for sensitivity anal- ysis, methods for sparse surrogate construction, and Bayesian inference tools for inferring parameters from experimental data. This manual discusses the download and installation process for UQTk, provides pointers to the UQ methods used in the toolkit, and describes some of the examples provided with the toolkit.

  7. 来吧!WEB 2.0

    2005-01-01

    @@ 互联网从不缺少慨念和焦点,从木子美到芙蓉姐姐都在网上掀起不大不小的风波,但这次风暴的中心却是互联网本身,是互联网未来的发展方向,卷入的人群远非"粉丝"那么简单,而是一些互联网的精英们,在这场风暴中一个新的名词进入我们的视线:Web 2.0.

  8. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    Cavinato, C.C. [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil); Campos, L.L., E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil)

    2010-07-21

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  9. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  10. Electron capture and transfer-ionization processes in 4He2++Ar collision at 12.5 keV amu-1

    Electron emission in the 4He2++Ar collisional system has been investigated at 35 deg. and 12.5 keV amu-1 collision velocity, in coincidence with the recoil target ion charges. Direct single ionization is found to be negligible with respect to single-electron capture. Contributions of transfer-ionization processes are stressed in the production of Ar2+ to Ar4+ ions; those of direct ionization, double excitation of the target and double capture into autoionization states of helium are instead found to be much less probable. Among the two-electron processes which explain the formation of Ar2+ ions, the double capture into autoionizing states of helium remains unimportant with respect to a pure transfer ionization process (one captured electron plus one ionized electron). The measured predominant production of Ar3+ ions illustrates the role played by three-electron processes, mainly a two-electron transfer accompanied by a single-target ionization. Finally, the formation of Ar4+ ions is connected with more complex transfer ionization processes. A qualitative analysis of these results is made within the quasimolecular approach. (author). Letter-to-the-editor

  11. Web 2.0 and competitiveness improvement

    Bauerová, Danuše

    2011-12-01

    Full Text Available Article shows implementation of A Model of Learning Powered by Technology at university environment. A Positive Digital Identity development on Web2.0 cloud is presented. People are creating their own portfolios - Personal Learning Portfolio and Personal Credit Portfolio. The part of it such proposals are generalizing methodologies to be useful to improve competitiveness of students, pedagogues, scientists but also institutions as well as anybody of lifelong learning activities.

    Este artículo muestra la puesta en marcha de un modelo de aprendizaje potenciado por la tecnología en el entorno de la Universidad. Se presenta un desarrollo de la Identidad Digital Positiva sobre la nube Web2.0. Las personas crean sus propios portafolios –Personal Learning Portfolio y Personal Credit Portfolio. Por otra parte, estas propuestas representan la generalización de metodologías que son útiles para mejorar la competitividad de estudiantes, pedagogos, científicos, pero también de las instituciones, así como de las actividades de aprendizaje a lo largo de la vida.

  12. 20-element HgI2 energy dispersive x-ray array detector system

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20-element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-Kalpha) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken form diluted samples simulating proteins with nickel

  13. 20 element HgI sub 2 energy dispersive x-ray array detector system

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. (Xsirius, Inc., Marina Del Rey, CA (United States)); Hedman, B.; Hodgson, K.O. (Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.); Patt, B.E. (EG and G Energy Measurements, Inc., Goleta, CA (United States))

    1991-01-01

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  14. 20 element HgI{sub 2} energy dispersive x-ray array detector system

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. [Xsirius, Inc., Marina Del Rey, CA (United States); Hedman, B.; Hodgson, K.O. [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.; Patt, B.E. [EG and G Energy Measurements, Inc., Goleta, CA (United States)

    1991-12-31

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  15. 20-element HgI[sub 2] energy dispersive x-ray array detector system

    Iwanczyk, J.S.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. (Xsirius, Inc., Marina del Ray, CA (United States)); Hedman, B.; Hodgson, K.O. (Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.); Patt, B.E. (EG and G Energy Measurements, Inc., Goleta, CA (United States))

    1992-10-01

    This paper describes recent progress in the development of HgI[sub 2] energy dispersive x-ray arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20-element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K[sub alpha]) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken form diluted samples simulating proteins with nickel.

  16. 20 element HgI2 energy dispersive x-ray array detector system

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-Ka) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel

  17. The 20 element HgI2 energy dispersive x ray array detector system

    Iwanczyk, J. A.; Dorri, N.; Wang, M.; Szczebiot, R. W.; Dabrowski, A. J.; Hedman, B.; Hodgson, K. O.; Patt, B. E.

    1991-11-01

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K(sub a)) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  18. Nucleosynthesis confronts an unstable inert 17 keV state

    We study the cosmological consequences of an inert 17 keV state mixing with the electron neutrino. We find that the nucleosynthesis upper bound on the primordial helium abundance prohibits the existence of such a state, unless its lifetime falls into the range 6x10-4svac-2s. In this range the decay occurs after the chemical decoupling of the electron neutrinos and before the beginning of the nucleosynthesis, with the result that the predicted helium abundance can be lower than what it would be in the standard scenario. (orig.)

  19. Measurement of L subshell photoionisation cross sections of Th and U at 22.6, 25.8, 29.2 and 32.9 kev

    Santra, S. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Mitra, D. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Sarkar, M. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)]. E-mail: manoranjan.sarkar@saha.ac.in; Bhattacharya, D. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2007-10-15

    Bremsstrahlung from an X-ray tube was used to excite secondary targets of Ag, Sn, I and Ba to get nearly monochromatic excitation energies of 22.6, 25.8, 29.2 and 32.9 keV, respectively. Th and U were used as targets. The L X-ray fluorescence cross sections of different lines from the targets have been measured. Of the several methods to obtain L subshell photoionisation cross sections from these fluorescence data, the merits and demerits of four common methods have been explained and the method with least uncertainty was suggested as the best one for such analysis. Following this method, with intensities of the resolved L {sub {gamma}} lines, three L subshell photoionisation cross sections have been obtained using six different sets of atomic parameters. The variation of these cross sections with different atomic parameters has been discussed. For {sigma} {sub 1}, all the derived values are within 30% of one other while for {sigma} {sub 2} and {sigma} {sub 3}, they are within 12%. Measured cross sections have been compared with the data of others and with the theoretical values of Scofield. Finally, the intensity ratios of different L lines have also been compared with available data and the theoretical values. Within experimental errors, our data are in good agreement with the data of others and with the theoretical predictions.

  20. Evaluation of the 232Th neutron capture cross section above 3 keV

    This memo describes an evaluation of the 232Th neutron capture cross section in the neutron energy range from 3 keV to 20 MeV. Most existing differential measurements are reviewed, and some data are renormalized to current values of the standards. Several experimentally determined sets of average resonance parameters are also discussed. From 3 to 50 keV the evaluated cross section is described by a set of average statistical resonance parameters. Above 50 keV the evaluated capture cross section is a smooth curve which follows the trend of the most recent measurements. The evaluated capture cross section is compared with many measurements and uncertainty estimates are given

  1. M2-Branes And The (2,0) Superalgebra

    Lambert, Neil

    2016-01-01

    We present a generalization of the six-dimensional (2,0) system of arXiv:1007.2982 to include a constant abelian 3-form. For vanishing 3-form this system is known to provide a variety descriptions of parallel M5-branes. For a particular choice of 3-form the system is shown to reduce to that of two M2-branes. Thus this generalised (2,0) system provides a unified description of two parallel M2-branes or M5-branes.

  2. The Immune Epitope Database 2.0

    Hoof, Ilka; Vita, R; Zarebski, L;

    2010-01-01

    The Immune Epitope Database (IEDB, www.iedb.org) provides a catalog of experimentally characterized B and T cell epitopes, as well as data on Major Histocompatibility Complex (MHC) binding and MHC ligand elution experiments. The database represents the molecular structures recognized by adaptive...... unavailable to the public from 129,186 experiments were submitted directly by investigators. The curation of epitopes related to autoimmunity is expected to be completed by the end of 2010. The database can be queried by epitope structure, source organism, MHC restriction, assay type or host organism, among...... other criteria. The database structure, as well as its querying, browsing and reporting interfaces, was completely redesigned for the IEDB 2.0 release, which became publicly available in early 2009....

  3. Teaching PBL with Web 2.0

    Dohn, Nina Bonderup; Buus, Lillian

    2013-01-01

    , the teacher of the BA-level problem-based learning course, sighed as he read through the Facebook postings entered by his students during the last 10 hours. Where were the theoretical questions and methodological issues he had been expecting? Once again, the students had posted links to YouTube videos...... of competences necessary for participating in contemporary society. In this article we report on a study of three cases where web 2.0 activities have been introduced into PBL settings. Our focus is the unexpected challenges teachers may face due to inherent tensions between the practice logic of the educational...... seemed to be completely overlooked by the students. Even worse, a lot of the postings never got beyond practicalities such as length requirements or meeting schedules. Why didn’t the students make use of this opportunity to build knowledge together, and to reflect and discuss with each other and with him...

  4. LA WEB 2.0 EN ESCENA.

    Raúl Santiago Campión

    2012-01-01

    Full Text Available En este artículo pretendemos desarrollar un análisis crítico sobre los denominados entornos Web 2.0. Para ello comenzaremos un recorrido "histórico" sobre el origen del término para después realizar una descripción de sus características, lo que nos permitirá abordar su funcionamiento técnico. Todo ello nos debe servir para tratar de comprender si nos encaminamos hacia el denominado modelo "3.0". Concluiremos con una crítica constructiva de algunos aspectos relevantes que se han venido mencionando en torno al concepto de web colaborativa.

  5. Web 2.0

    Boistel, Philippe

    2013-01-01

    Avec le développement du Web 2.0, les entreprises sont de plus en plus sollicitées et parfois mises en accusation sur la Toile. La conséquence majeure se porte sur l’e-réputation qui peut être considérée comme la réputation ressortant des conversations issues d’Internet. Les entreprises cherchent à gérer cette e-réputation et les conséquences de ces mises en accusation sur les cours boursiers, les candidatures, et les ventes. A partir de quatre études de cas français, l’auteur analyse comment...

  6. The 2-10 keV unabsorbed luminosity function of AGN from the XMM-Newton LSS, CDFS and COSMOS surveys

    Ranalli, P; Georgantopoulos, I; Fotopoulou, S; Hsu, L -T; Salvato, M; Comastri, A; Pierre, M; Cappelluti, N; Carrera, F J; Chiappetti, L; Clerc, N; Gilli, R; Iwasawa, K; Pacaud, F; Paltani, S; Plionis, E; Vignali, C

    2015-01-01

    The XMM-LSS, XMM-COSMOS, and XMM-CDFS surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and PSF. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of AGN and its evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 10^42-10^46 erg/s, and in the redshift interval 0.001-4. A new method to correct for absorption by considering the probability distribution for the column density conditioned on the hardness ratio is presented. The binned luminosity function and its evolution is determined with a variant of the Page-Carrera method, improved to include corrections for absorption and to account for the full probability distribution of photometric redshifts. Parametric models, namely a double power-law with LADE or LDDE evolution, are explored using Bayesian in...

  7. Spectral albedo of photons of initial energies below 100 keV

    This paper shows the results of Monte Carlo simulations of the photon reflection from homogenous plates of the shield materials made of water, aluminum, and iron. Perpendicular incidence of a monoenergetic photon beam of the initial energy of 20 keV up to 100 keV is considered. The numerical experiments were performed using the verified Monte Carlo programs MCNP-4C, FOTELP-2K3, and PENELOPE-2005. As the result, the values of difference number albedo distributed in ten even intervals according to the energy and nine even intervals according to the polar angle of reflected photons were obtained. Out of these data, the spectral albedo coefficients for all three materials and three initial photon energies of 40 keV, 60 keV, and 100 keV were calculated, graphically presented, and analyzed. The values of the spectral albedo determined on the basis of MCNP-4C code were compared to the results of the early simulations of the photon reflection performed in Russia and in the USA. Also, with the help of MCNP-4C program, the yield of fluorescent photons to the spectrum of the reflected radiation was registered, which can be seen in the graphs in the form of the peak at the energy of 7.112 keV only at the shielding plates made of iron. (author)

  8. A measurement of the electron-hole pair creation energy and the Fano factor in silicon for 5.9 keV X-rays and their temperature dependence in the range 80-270 K

    A measurement of the energy ω to create an electron-hole pair and its temperature dependence between 80 and 270 K has been made using a small Si p-i-n diode and 5.9 keV X-rays. A value of 3.73±0.09 eV with a gradient of -0.0131±0.0004% K-1 was found. The photo-peak dispersion D was also measured and from the values between 110 K and 235 K, the product ωF was found to be 0.441±0.005 eV. This is consistent with a constant Fano factor F of 0.118±0.004

  9. Energy dependence of the air kerma response of a liquid ionization chamber at photon energies between 8 keV and 1250 keV

    Full text: In its recent reports on cardiovascular brachytherapy the DGMP recommends the source strength of brachytherapy sources being characterized in terms of absorbed dose to water at a distance of 2 mm from the central axis of the source. As a consequence, the response of a detector suitable for characterizing such sources with respect to absorbed dose to water should depend only to a small extent on radiation energy. Additionally, the detection volume of the detector has to be sufficiently small for the necessary spatial resolution to be obtained. The liquid ionization chamber as described in seems to be a promising means for this type of measurements. The two components of the ionization liquid (TMS and isooctane) can be mixed in a ratio which ensures that the mass-energy absorption coefficient of the resulting mixture deviates from that of water by less than ±15 % down to photon energies of 10 keV. Due to the high density of the ionization medium, the spacing between the two electrodes of the ionization chamber can be made as small as a few tenths of a millimeter and still the resulting ionization current is sufficiently large. The ionization chamber used in the present investigation is a plane parallel chamber 5 mm in diameter and of 0.3 mm electrode spacing. The ionization medium is a mixture of 40 % TMS and 60 % isooctane. The irradiations were carried out with the ISO wide spectra series with tube voltages between 10 kV and 300 kV and with 137Cs and 60Co γ-radiation. As a first step, the response of the liquid ionization chamber was investigated with respect to air kerma instead of absorbed dose to water. Although the mass-energy absorption coefficient of the liquid deviates from that of air by less than ±10 % over the photon energy range, the measured chamber response varies by a factor of about 3.5. Monte Carlo calculations carried out with EGSnrc show a variation of the chamber response smaller than ±20 %. Measurements of the ion yield of the

  10. BSD Portals for LINUX 2.0

    McNab, A. David; woo, Alex (Technical Monitor)

    1999-01-01

    Portals, an experimental feature of 4.4BSD, extend the file system name space by exporting certain open () requests to a user-space daemon. A portal daemon is mounted into the file name space as if it were a standard file system. When the kernel resolves a pathname and encounters a portal mount point, the remainder of the path is passed to the portal daemon. Depending on the portal "pathname" and the daemon's configuration, some type of open (2) is performed. The resulting file descriptor is passed back to the kernel which eventually returns it to the user, to whom it appears that a "normal" open has occurred. A proxy portalfs file system is responsible for kernel interaction with the daemon. The overall effect is that the portal daemon performs an open (2) on behalf of the kernel, possibly hiding substantial complexity from the calling process. One particularly useful application is implementing a connection service that allows simple scripts to open network sockets. This paper describes the implementation of portals for LINUX 2.0.

  11. Application of Web 2.0 Tools in Medical Librarianship to Support Medicine 2.0

    V. Vishwa Mohan

    2008-03-01

    Full Text Available It is almost a decade that social networking technology along with its tools such as blogs, wikis, slidesharing/videosharing and photosharing softwares, podcasts, RSS feeds, mashups, folksonomies, and bookmarks has developed its influence on all human fields of study/activity. It is obvious that these tools are increasingly growing, in different languages, regions and fields, due to social dynamic and liberal characteristic of Web 2.0 technologies. Medical sciences and library science also are not exception to this influence. Consequently, library 2.0 and newly coined concepts of Medicine 2.0, and Health 2.0 have become the buzzwords in the Internet culture. In spite of proliferation of such social tools listed above, there is no aggregation and harmony for the utilization of the potential of these technologies in specific subject areas and the sources of information on the Web is almost proliferating and uncontrolled. This gives rise to the problem of webliographic control due to which the information seekers find difficulties in information retrieval. The paper presents application of Web 2.0 in medical libraries to support Medicine 2.0 emphasizing the above-mentioned problems. Considering the nature of an original article the experience of the authors, as a medical librarian and a faculty member in Library and Information Science, through observation of the needs, problems and prospects, played an important role in forming the idea and presentation. The study also used secondary data collected from related literatures. Standardization and webliographic control would solve the problem. In addition, governmental support and creating awareness at the management level in the organizations is also crucial.

  12. Problems for (2,0) compactifications

    Several theoretical and phenomenological problems are exposed which impede the construction of realistic low-energy models based on the superstring using manifolds for which the gauge and spin connections are not identified (A not equal to ω), and the world-sheet σ-model has (2,0) supersymmetry. Single worldsheet instantanons generate an effective scalar potential which prevents generic manifolds of this type from being solutions to the equations of motion. They also give large supersymmetry-breaking mass parameters O(m/sub p/) to gauge non-singlet fields. The Green-Schwarz modification to the anti-symmetric tensor field strength may not absorb anomalies if ω not equal to A. It is difficult to obtain satisfactory mixing among the supersymmetric Weinberg-Salem Higgs fields, which requires an SU(3) x SU(2) x U(1) singlet field N with vacuum expectation value x identical to = (m/sub W/). A Yukawa coupling λ N3 would yield x = O(m/sub W/), but at the expense of cosmologically unacceptable domain walls. If there is no such Yukawa coupling, the natural value for x is O(m/sub P/)

  13. Web 2.0 and Critical Information Literacy

    Dunaway, Michelle

    2011-01-01

    The impact of Web 2.0 upon culture, education, and knowledge is obfuscated by the pervasiveness of Web 2.0 applications and technologies. Web 2.0 is commonly conceptualized in terms of the tools that it makes possible, such as Facebook, Twitter, and Wikipedia. In the context of information literacy instruction, Web 2.0 is frequently conceptualized…

  14. TL response of single crystal TLD-100 to 70 eV: 5 keV electrons and comparison with TSEE glow curves

    Lasky, J.B.; Moran, P.R.

    1976-01-01

    A ''TL effective'' energy-range relationship was found which agrees with the universal curve above 2 keV but becomes nearly constant at about 300/sup 0/A for energies between 1 keV and 100 eV. The glow curve shape obtained from single crystal TLD-100, after irradiation with 70 eV to 30 keV electrons, is essentially the same as that obtained after irradiation with cesium ..gamma..-rays, (i.e. TL emitted from bulk of sample) as long as (1) the dose is well below saturation and (2) irradiations are performed on freshly cleaved crystals or vacuum annealed crystals. This result shows that there is no intrinsic difference between TL traps near the surface and in the bulk. Irradiation with electron energies less than 1 keV results in the TL signal being emitted from the same region from which TSEE electrons are emitted. The usual TSEE glow curve, found by other investigators, is different from the TL glow curve obtained from vacuum annealed crystals. However, if the TL sample is given the same ''standard annealing'' as is customary in TSEE experiments, the TL glow curve obtained after irradiation with low energy electrons is altered and there is then good agreement between this TL glow curve and the TSEE curve found by others. This altered glow curve is a result of hydroxyl ions which diffuse into the sample during annealing. The TL efficiency was comparable to cesium ..gamma..-rays for 30-5 keV electrons, decreased rapidly between 5 and 1 keV and remained constant at about 20% of the efficiency of cesium ..gamma..-rays below 1 keV. Half of this decrease in efficiency can be attributed to the higher LET of low energy electrons. The cause for the remaining decrease is not known but it may have its origin in the same mechanism proposed to account for the large range of low energy electrons.

  15. 36 CFR 222.2 - Management of the range environment.

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Management of the range environment. 222.2 Section 222.2 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE... environment. (a) Allotments will be designated on the National Forest System and on other lands under...

  16. Vacuum Insulation and Achievement of 980 keV, 185 A/m2 H− Ion Beam Acceleration at JAEA for the ITER Neutral Beam Injector

    Vacuum insulation of −1 MV is a common issue for the HV bushing and the accelerator for the ITER neutral beam injector (NBI). The HV bushing as an insulating feedthrough has a five-stage structure and each stage consists of double-layered insulators. To sustain −1 MV in vacuum, reduction of electric field at several triple points existing around the double-layered insulators is a critical issue. To reduce electric field simultaneously at these points, three types of stress ring have been developed. In a voltage holding test of a full-scale mockup equipped with these stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, whose target is the acceleration of a H− ion beam of 1 MeV, 200 A/m2, the gap between the grid support was extended to suppress breakdowns triggered by electric field concentration at the edge and corner of the grid support. This modification improved the voltage holding capability in vacuum, and the MeV accelerator succeeded in sustaining −1 MV stably. Furthermore, it appeared that the H− ions beam was deflected and a part of the beam was intercepted at the acceleration grid. This causes high heat load on the grids and breakdowns during beam acceleration. To suppress the direct interception, a new grid was designed with proper aperture displacement based on a three dimensional beam trajectory analysis. As a result, 980 keV, 185 A/m2 H− ion beam acceleration has been demonstrated, which is close to the ITER requirement. (fusion engineering)

  17. Oh! Web 2.0, Virtual Reference Service 2.0, Tools & Techniques (II)

    Arya, Harsh Bardhan; Mishra, J. K.

    2012-01-01

    The paper describes the theory and definition of the practice of librarianship, specifically addressing how Web 2.0 technologies (tools) such as synchronous messaging, collaborative reference service and streaming media, blogs, wikis, social networks, social bookmarking tools, tagging, RSS feeds, and mashups might intimate changes and how…

  18. From web 2.0 to learning games 2.0

    Duus Henriksen, Thomas

    2011-01-01

    Learning games often fail in taking into account the extensive knowledge adult learners often have on the subject taught. This paper reports from a reconfiguration of a current learning game on leadership styles called LEADER, which on basis of ideas from web 2.0, is reconfigured to include the...

  19. From Web 2.0 to Learning Games 2.0

    Duus Henriksen, Thomas

    2011-01-01

    Learning games often fail in taking into account the extensive knowledge adult learners often have on the subject taught. This paper reports from a reconfiguration of a current learning game on leadership styles called LEADER, which on basis of ideas from web 2.0, is reconfigured to include the...

  20. FLUTAN 2.0. Input specifications

    FLUTAN is a highly vectorized computer code for 3D fluiddynamic and thermal-hydraulic analyses in Cartesian or cylinder coordinates. It is related to the family of COMMIX codes originally developed at Argonne National Laboratory, USA, and particularly to COMMIX-1A and COMMIX-1B, which were made available to FZK in the frame of cooperation contracts within the fast reactor safety field. FLUTAN 2.0 is an improved version of the FLUTAN code released in 1992. It offers some additional innovations, e.g. the QUICK-LECUSSO-FRAM techniques for reducing numerical diffusion in the k-ε turbulence model equations; a higher sophisticated wall model for specifying a mass flow outside the surface walls together with its flow path and its associated inlet and outlet flow temperatures; and a revised and upgraded pressure boundary condition to fully include the outlet cells in the solution process of the conservation equations. Last but not least, a so-called visualization option based on VISART standards has been provided. This report contains detailed input instructions, presents formulations of the various model options, and explains how to use the code by means of comprehensive sample input. (orig.)

  1. Checking Potassium origin of new emission line at 3.5 keV with K XIX line complex at 3.7 keV

    Iakubovskyi, Dmytro

    2015-01-01

    Whether the new line at ~3.5 keV, recently detected in different samples of galaxy clusters, Andromeda galaxy and central part of our Galaxy, is due to Potassium emission lines, is now unclear. By using the latest astrophysical atomic emission line database AtomDB v. 3.0.2, we show that the most prospective method to directly check its Potassium origin will be the study of K XIX emission line complex at ~3.7 keV with future X-ray imaging spectrometers such as Soft X-ray spectometer on-board Astro-H mission or microcalorimeter on-board Micro-X sounding rocket experiment. To further reduce the remaining (factor ~3-5) uncertainty of the 3.7/3.5 keV ratio one should perform more precise modeling including removal of significant spatial inhomogeneities, detailed treatment of background components, and further extension of the modeled energy range.

  2. Characteristics of > 290 keV magnetosheath ions

    A. Rigas

    Full Text Available We performed a statistical analysis of 290-500 keV ion data obtained by IMP-8 during the years 1982-1988 within the earth's magnetosheath and analysed in detail some time periods withdistinct ion bursts. These studies reveal the following characteristics for magnetosheath 290-500 keV energetic ions: (a the occurrence frequency and the flux of ions increase with increasing geomagnetic activity as indicated by the Kp index; the occurrence frequency was found to be as high as P > 42% for Kp > 2, (b the occurrence frequency in the dusk magnetosheath was found to be slightly dependent on the local time and ranged between ~30% and ~46% for all Kp values; the highest occurrence frequency was detected near the dusk magnetopause (21 LT, (c the high energy ion bursts display a dawn-dusk asymmetry in their maximum fluxes, with higher fluxes appearing in the dusk magnetosheath, and (d the observations in the dusk magnetosheath suggest that there exist intensity gradients of energetic ions from the bow shock toward the magnetopause. The statistical results are consistent with the concept that leakage of magnetospheric ions from the dusk magnetopause is a semi-permanent physical process often providing the magnetosheath with high energy (290-500 keV ions.Key words. Magnetospheric physics (magnetosheath; planetary magnetospheres. Space plasma physics (shock waves.

  3. Non-dissociative and dissociative ionization of N{sub 2}, CO, CO{sub 2}, and CH{sub 4} by impact of 50-6000 keV protons and antiprotons

    Knudsen, H.; Mikkelsen, U.; Paludan, K. [Aarhus Univ. (Denmark). Inst. for Fysik og Astronomi; Kirsebom, K.; Moeller, S.P.; Uggerhoej, E. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiation; Slevin, J. [Saint Patrick`s Coll., Maynooth (Ireland). Dept. of Experimental Physics; Charlton, M. [University Coll., London (United Kingdom). Dept. of Physics and Astronomy; Morenzoni, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1995-08-28

    Measurements of the cross section for non-dissociative single ionization and the cross sections for the creation of charged fragments have been performed for 50-6000 keV antiproton and proton impact on N{sub 2}, CO, CO{sub 2}, and CH{sub 4}. The results support the understanding of the ionization phenomenon that has been achieved via measurements with fundamental charged particles on atoms. The present high-energy antiproton fragmentation data supply a stringent test of the validity of the published electron-impact fragmentation data which, unfortunately, most of them fail. (Author).

  4. Evaluation of the 1077 keV γ-ray emission probability from 68Ga decay

    68Ga decays to the excited states of 68Zn through the electron capture decay mode. New recommended values for the emission probability of 1077 keV γ-ray given by the ENSDF and DDEP databases all use data from absolute measurements. In 2011, JIANG Li-Yang deduced a new value for 1077 keV γ-ray emission probability by measuring the 69Ga(n, 2n) 68Ga reaction cross section. The new value is about 20% lower than values obtained from previous absolute measurements and evaluations. In this paper, the discrepancies among the measurements and evaluations are analyzed carefully and the new values are re-recommended. Our recommended value for the emission probability of 1077 keV γ-ray is (2.72±0.16)%. (authors)

  5. Web 2.0, Internet 2.1?

    Ulf-Dietrich Reips; Uwe Matzat

    2007-01-01

    Welcome to issue 2.0 of the International Journal of Internet Science. The "2" is meant to mark a distinct event, even though articles in the International Journal of Internet Science are continuously uploaded to our "in press" section, as soon as they have been reviewed, editorially lettered, revised, copy edited, and cleared for publication. The continuous flow of the publication process and its matching companion, seamless technologies for Internet-based Open Access publishing, seem to ren...

  6. A new approach for precise measurements of keV neutron capture cross sections: The examples of 93Nb, 103Rh, and 181Ta

    A new experimental method has been implemented for precise measurements of neutron capture cross sections in the energy range from 3 to 200 keV. Neutrons are produced via the 7Li(p,n)7Be reaction using a pulsed 3 MV Van de Graaff accelerator. The neutron energy is determined by the time of flight technique using flight paths of less than 1 m. Capture events are detected with the Karlsruhe 4π Barium Fluoride Detector. This detector is characterized by a resolution in gamma-ray energy of 14% at 662 keV and 7% at 2.5 MeV, a time resolution of 500 ps, and a peak efficiency of 90% at 1 MeV. Capture events are registered with ≅ 95% probability above a gamma-ray threshold of 2.5 MeV. The combined effect of the relatively short primary flight path, the 10 cm inner radius of the detector sphere, and of the low capture cross section of BaF2 allows to discriminate the main background due to capture of sample scattered neutrons in the scintillator via time of flight, leaving part of the neutron energy range completely undisturbed. The high efficiency and good energy resolution for capture gamma-rays yields a further reduction of this background by using only the relevant energy channels for data evaluation. In the first measurements with the new detector, the neutron capture cross sections of 93Nb, 103Rh, and 181Ta were determined in the energy range from 3 to 200 keV relative to gold as a standard. The cross section ratios could be determined with overall systematic uncertainties of 0.7 to 0.8%; statistical uncertainties were less than 1% in the energy range from 20 to 100 keV, if the data are combined in 20 keV wide bins. The necessary sample masses were of the order of one gram. Further improvements with respect to sensitivity and accuracy are discussed. (orig.)

  7. The r-Java 2.0 code: nuclear physics

    Kostka, M.; Koning, N.; Shand, Z.; Ouyed, R.; Jaikumar, P.

    2014-08-01

    Aims: We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations, along with a suite of other analysis tools. Methods: Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission and studying individual nucleosynthesis processes. Results: In this paper we discuss enhancements to this version of r-Java, especially the ability to solve the full reaction network. The sophisticated fission methodology incorporated in r-Java 2.0 that includes three fission channels (beta-delayed, neutron-induced, and spontaneous fission), along with computation of the mass fragmentation, is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studied. The role of Coulomb interactions in NSE abundances is shown to be significant, supporting previous findings. A comparative analysis was undertaken during the development of r-Java 2.0 whereby we reproduced the results found in the literature from three other r-process codes. This code is capable of simulating the physical environment of the high-entropy wind around a proto-neutron star, the ejecta from a neutron star merger, or the relativistic ejecta from a quark nova. Likewise the users of r-Java 2.0 are given the freedom to define a custom environment. This software provides a platform for comparing proposed r-process sites.

  8. Efficient focusing of 8 keV X-rays with multilayer Fresnel zone plates fabricated by atomic layer deposition and focused ion beam milling.

    Mayer, Marcel; Keskinbora, Kahraman; Grévent, Corinne; Szeghalmi, Adriana; Knez, Mato; Weigand, Markus; Snigirev, Anatoly; Snigireva, Irina; Schütz, Gisela

    2013-05-01

    Fresnel zone plates (FZPs) recently showed significant improvement by focusing soft X-rays down to ~10 nm. In contrast to soft X-rays, generally a very high aspect ratio FZP is needed for efficient focusing of hard X-rays. Therefore, FZPs had limited success in the hard X-ray range owing to difficulties of manufacturing high-aspect-ratio zone plates using conventional techniques. Here, employing a method of fabrication based on atomic layer deposition (ALD) and focused ion beam (FIB) milling, FZPs with very high aspect ratios were prepared. Such multilayer FZPs with outermost zone widths of 10 and 35 nm and aspect ratios of up to 243 were tested for their focusing properties at 8 keV and shown to focus hard X-rays efficiently. This success was enabled by the outstanding layer quality thanks to ALD. Via the use of FIB for slicing the multilayer structures, desired aspect ratios could be obtained by precisely controlling the thickness. Experimental diffraction efficiencies of multilayer FZPs fabricated via this combination reached up to 15.58% at 8 keV. In addition, scanning transmission X-ray microscopy experiments at 1.5 keV were carried out using one of the multilayer FZPs and resolved a 60 nm feature size. Finally, the prospective of different material combinations with various outermost zone widths at 8 and 17 keV is discussed in the light of the coupled wave theory and the thin-grating approximation. Al2O3/Ir is outlined as a promising future material candidate for extremely high resolution with a theoretical efficiency of more than 20% for as small an outermost zone width as 10 nm at 17 keV. PMID:23592622

  9. Da Web 2.0 ao E-learning 2.0 : aprender na rede

    Mota, José Carlos

    2009-01-01

    A emergência da Web 2.0, ou Read/Write Web, é algo que vai muito para além do mero domínio tecnológico: ela é, mais do que uma revolução tecnológica, uma revolução social e cultural, estendendo-se a todas as áreas da sociedade. Em poucos anos, a Web 2.0 mudou radicalmente a forma como as pessoas utilizam a Internet e interagem com os outros, com a informação e com o conhecimento. De consumidores de conteúdos e informação, estes novos cidadãos digitais passaram também a ser produtores de infor...

  10. Birding 2.0: Citizen Science and Effective Monitoring in the Web 2.0 World

    Wiersma, Yolanda F.

    2010-01-01

    The amateur birding community has a long and proud tradition of contributing to bird surveys and bird atlases. Coordinated activities such as Breeding Bird Atlases and the Christmas Bird Count are examples of "citizen science" projects. With the advent of technology, Web 2.0 sites such as eBird have been developed to facilitate online sharing of data and thus increase the potential for real-time monitoring. However, as recently articulated in an editorial in this journal and elsewhe...

  11. 58Ni + n transmission, differential elastic scattering and capture measurements and analysis from 5 to 813 keV

    High-resolution neutron measurements for 58Ni-enriched targets were made at the Oak Ridge Electron Linear Accelerator (ORELA) from 100 eV to ∼20 MeV in transmission, from 10 keV to 5 MeV in differential elastic, and from 2.5 keV to 5 MeV in capture. The transmission data were analyzed from 10 to 813 keV with the multilevel R-matrix code SAMMY which uses Bayes' theorem for the fitting process. This code provides energies and neutron widths of the resonances inside the 10- to 813-keV region as well as a possible parameterization for resonances external to that region to describe the smooth cross section from 10 to 813 keV. The differential elastic data at different scattering angles were compared to theoretical calculations from 30 to 813 keV using an R-matrix code based on the Blatt-Biedenharn formalism. Various combinations of spin and parity were tried to predict cross sections for the well defined /ell/ > 0 resonances, and comparison with the data then provided spin and parity assignments for most of these resonances. the capture data were analyzed from 5 to 450 keV with a least-squares fitting code using the Breit-Wigner formula. In this energy region 30% more resonances were observed in the capture data than in the transmission data. 55 refs., 44 figs., 3 tabs

  12. Web 2.0 and health 2.0: are you in?

    Felkey, Bill G

    2008-01-01

    With over 6 billion web pages, over $100 billion in online sales every year in the U.S. alone and the average growth rate of online purchasing exceeding 26% over the last 5 years, the Internet is a powerful business tool. Today's shopper sees your actual pharmacy location and your Internet presence as one and the same. One study showed that 82% of the consumers surveyed who had a single frustrating experience online with a retailer would not return to the site for future dealings. A bad experience online made 28% of those surveyed unlikely to return to the retail location of the business, and over 55% said a bad online experience would have a negative impact on their overall opinion of the retailer. Web 2.0 refers to the social networking applications of the internet, Health 2.0 to its special health applications. Taking your Internet presence to the 2.0 level must be balanced with all of the other demands you are facing-but be aware that it's happening all around you. PMID:23969714

  13. Neutron-capture cross sections of the tungsten isotopes 182W, 183W, 184W, and 186W from 2.6 to 2000 keV

    Neutron-capture cross sections of four stable tungsten isotopes were measured as a function of energy by time of flight at the Oak Ridge Electron Linear Accelerator. The resolution achieved, ΔE/E about 1/750 FWHM, has allowed the analysis of several hundred resonance peaks at energies a few kiloelectron volts above the neutron-binding energy. Strength functions were fitted to the average cross sections up to about 100 keV, and average cross sections were extended with less precision from 100 to 2000 keV. The capture cross section of natural tungsten was calculated from measurements for individual isotopes. Compound nucleus calculations have been made with deformed optical model parameters for comparison with experimental cross sections

  14. A rigorous semantics for BPMN 2.0 process diagrams

    Kossak, Felix; Geist, Verena; Kubovy, Jan; Natschläger, Christine; Ziebermayr, Thomas; Kopetzky, Theodorich; Freudenthaler, Bernhard; Schewe, Klaus-Dieter

    2015-01-01

    This book provides the most complete formal specification of the semantics of the Business Process Model and Notation 2.0 standard (BPMN) available to date, in a style that is easily understandable for a wide range of readers - not only for experts in formal methods, but e.g. also for developers of modeling tools, software architects, or graduate students specializing in business process management. BPMN - issued by the Object Management Group - is a widely used standard for business process modeling. However, major drawbacks of BPMN include its limited support for organizational modeling, i

  15. Solar Advisor Model User Guide for Version 2.0

    Gilman, P.; Blair, N.; Mehos, M.; Christensen, C.; Janzou, S.; Cameron, C.

    2008-08-01

    The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.

  16. Primary standard for the number concentration of liquid-borne particles in the 10 to 20 µm diameter range

    The national primary standard for the number concentration of liquid-borne particles in the 10 to 20 µm diameter range has been developed at the National Institute of Advanced Industrial Science and Technology (AIST), Japan. The standard consists of a total number counting type flow cytometer (T-FCM) and an electronic balance. The T-FCM is a commercial flow cytometer modified so that the total number of particles in an aqueous suspension sampled in a test tube can be counted, and the electronic balance is used to determine the mass of the suspension. This standard is intended to be used for calibrating commercial standard suspensions of monodisperse polystyrene latex (PSL) particles. The measurand in the calibration is the mass-based number concentration (the particle number in a unit mass of a suspension), and the calibration capability covers the concentration range from 5 × 102 to 2 × 106 particles g−1. When the concentration of the suspension is higher than 2 × 103 particles g−1, the suspension is first diluted to about 1 × 103 particles g−1 to suppress the coincidence loss in particle counting by the T-FCM. The validity of the calibration with the T-FCM was examined by comparison with an independent method in which a scanning electron microscope (SEM) was used to determine the number concentration of particles deposited on a silicon wafer. For a suspension of 10 µm PSL particles with a concentration of approximately 1 × 106 particles g−1, the concentration values determined by the T-FCM and SEM methods were 1.042 × 106 and 1.035 × 106 particles g−1, respectively: The difference was less than 0.7%. The relative expanded uncertainty of the measurement by the T-FCM method with the coverage factor k = 2 was 4.4%

  17. ESTAR, PSTAR, ASTAR. A PC package for calculating stopping powers and ranges of electrons, protons and helium ions. Version 2

    A PC package is documented for calculating stopping powers and ranges of electrons, protons and helium ions in matter for energies from 1 keV up to 10 GeV. Stopping powers and ranges for electrons can be calculated for any element, compound or mixture. Stopping powers and ranges of protons and helium ions can be calculated for 74 materials (26 elements and 48 compounds and mixtures). The files are stored on two HD diskettes in compressed form. Both executable files for IBM PC and Fortran-77 source files are provided. All three programs require 5.2 Mb of disk space. This set of two diskettes with detailed documentation is available upon request, cost free, from the IAEA Nuclear Data Section. (author). 25 refs, 4 tabs

  18. Spatial distribution of upstream magnetospheric ≥50 keV ions

    G. Kaliabetsos

    Full Text Available We present for the first time a statistical study of geq50 keV ion events of a magnetospheric origin upstream from Earth's bow shock. The statistical analysis of the 50-220 keV ion events observed by the IMP-8 spacecraft shows: (1 a dawn-dusk asymmetry in ion distributions, with most events and lower intensities upstream from the quasi-parallel pre-dawn side (4 LT-6 LT of the bow shock, (2 highest ion fluxes upstream from the nose/dusk side of the bow shock under an almost radial interplanetary magnetic field (IMF configuration, and (3 a positive correlation of the ion intensities with the solar wind speed and the index of geomagnetic index Kp, with an average solar wind speed as high as 620 km s-1 and values of the index Kp > 2. The statistical results are consistent with (1 preferential leakage of ~50 keV magnetospheric ions from the dusk magnetopause, (2 nearly scatter free motion of ~50 keV ions within the magnetosheath, and (3 final escape of magnetospheric ions from the quasi-parallel dawn side of the bow shock. An additional statistical analysis of higher energy (290-500 keV upstream ion events also shows a dawn-dusk asymmetry in the occurrence frequency of these events, with the occurrence frequency ranging between ~16%-~34% in the upstream region.Key words. Interplanetary physics (energetic particles; planetary bow shocks

  19. Muutuste teel : raamatukogu 2.0 / Kate-Riin Kont

    Kont, Kate-Riin, 1971-

    2007-01-01

    7.-10. maini 2007. a Helsingis ja Tallinnas toimunud raamatukogufoorumist "Muutuste teel: Library 2.0 (Making a difference - Moving towards Library 2.0), millel esines ettekandega suhteturundusest Tallinna Ülikooli infoteaduse osakonna dotsent Aira Lepik

  20. NOAA-CIRES 20th Century Reanalysis (V2)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 20th Century Reanalysis version 2 (20CRV2)is an effort led by PSD and the CIRES at the University of Colorado to produce a reanalysis dataset spanning the...

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

    The linear attenuation coefficients and three interaction processes have been computed for liver, kidney, muscle, fat and for a range of x-ray energies from 1 keV to 150 keV. Molecular photoelectric absorption cross sections were calculated from atomic cross section data. Total coherent (Rayleigh) and incoherent (Compton) scattering cross sections were obtained by numerical integration over combinations of F2m(x) with the Thomson formula and Sm(x) with the Klein–Nishina formula, respectively. For the coherent (Rayleigh) scattering cross section calculations, molecular form factors were obtained from recent experimental data in the literature for values of x<1 Å−1 and from the relativistic modified atomic form factors for values of x≥1 Å−1. With the inclusion of molecular interference effects in the coherent (Rayleigh) scattering, more accurate knowledge of the scatter from these tissues will be provided. The number of elements involved in tissue composition is 5 for liver, 47 for kidney, 44 for muscle and 3 for fat. The results are compared with previously published experimental and theoretical linear attenuation coefficients. In general, good agreement is obtained. The molecular form factors and scattering functions and cross sections are incorporated into a Monte Carlo program. The energy distributions of x-ray photons scattered from tissues have been simulated and the results are presented. - Highlights: • The inclusion of molecular interference effects will provide new information. • Results are compared with previously reported experimental and theoretical values. • Calculation is achieved in the presence of small concentrations of different atoms

  2. r-Java 2.0: the nuclear physics

    Kostka, M; Shand, Z; Ouyed, R; Jaikumar, P

    2014-01-01

    [Aims:] We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations as well as a suite of other analysis tools. [Methods:] Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of; simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission as well as the study of individual nucleosynthesis processes. [Results:] In this paper we discuss enhancements made to this version of r-Java, paramount of which is the ability to solve the full reaction network. The sophisticated fission methodology incorporated into r-Java 2.0 which includes three fission channels (beta-delayed, neutron-induced and spontaneous fission) as well as computation of the mass fragmentation is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studi...

  3. Enterprise Information System Architecture Based on Web 2.0

    YI Xiushuang; WANG Yu; LIU Jinghong; WEN Zhankao

    2006-01-01

    Enterprise information systems with a great use of Web 2.0 technologies will be more open, free, and more efficient.With the contrast between classic Web technologies and Web 2.0 technologies, we represent a sample of enterprise information system based on Web 2.0, and show how the use of Web 2.0 technologies changes the system data exchange model of the enterprise information systems and how it improves the efficiency and effectiveness of information systems.

  4. The 2-79 keV X-ray spectrum of the Circinus galaxy with NuSTAR, XMM-Newton, and Chandra: a fully Compton-thick active galactic nucleus

    Arévalo, P.; Bauer, F. E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Puccetti, S. [ASDC-ASI, Via del Politecnico, I-00133 Roma (Italy); Walton, D. J.; Fuerst, F.; Grefenstette, B. W.; Harrison, F. A.; Madsen, K. K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Koss, M. [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Brightman, M. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748, Garching bei München (Germany); Christensen, F. E. [Danish Technical University, Lyngby (Denmark); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Gandhi, P. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory and Department of Physics, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Madejski, G. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States); Marinucci, A. [Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); and others

    2014-08-20

    The Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission, we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of N {sub H} = (6-10) × 10{sup 24} cm{sup –2}, and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 10{sup 42} erg s{sup –1}. These values place Circinus along the same relations as unobscured AGNs in accretion rate versus Γ and L{sub X} versus L {sub IR} phase space. NuSTAR's high sensitivity and low background allow us to study the short timescale variability of Circinus at X-ray energies above 10 keV for the first time. The lack of detected variability favors a Compton-thick absorber, in line with the spectral fitting results.

  5. The 2-79 keV X-ray spectrum of the Circinus galaxy with NuSTAR, XMM-Newton, and Chandra: a fully Compton-thick active galactic nucleus

    The Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission, we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of N H = (6-10) × 1024 cm–2, and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 1042 erg s–1. These values place Circinus along the same relations as unobscured AGNs in accretion rate versus Γ and LX versus L IR phase space. NuSTAR's high sensitivity and low background allow us to study the short timescale variability of Circinus at X-ray energies above 10 keV for the first time. The lack of detected variability favors a Compton-thick absorber, in line with the spectral fitting results.

  6. Deriving a Typology of Web 2.0 Learning Technologies

    Bower, Matt

    2016-01-01

    This paper presents the methods and outcomes of a typological analysis of Web 2.0 technologies. A comprehensive review incorporating over 2000 links led to identification of over 200 Web 2.0 technologies that were suitable for learning and teaching purposes. The typological analysis involved development of relevant Web 2.0 dimensions, grouping…

  7. Using web 2.0 for health information

    Younger, Paula

    2011-01-01

    Since it was first formally described in 2004, what is known as Web 2.0 has affected every library and information sector. Web 2.0 has tremendous potential to transform health information delivery. This book offers a cohesive overview of how Web 2.0 is changing health and medical information work.

  8. Dynamic properties of Indiana, Fort Knox and Utah test range limestones and Danby Marble over the stress range 1 to 20 GPa

    Furnish, M.D.

    1994-12-01

    The responses of the following carbonate materials to shock loading and release have been measured: Indiana limestone (18% porosity; saturated and dry), Jeffersonville/Louisville Limestones (Fort Knox limestone) (variable dolomitization, low porosity), Danby Marble (essentially pure calcite; low porosity), and a limestone from the Utah Test and Training Range (low porosity, with 22% silica). Various experimental configurations were used, some optimized to yield detailed waveform information, others to yield a clean combination of Hugoniot states and release paths. All made use of velocity interferometry as a primary diagnostic. The stress range of 0 - 20 GPa was probed (in most cases, emphasizing the stress range 0 -10 GPa). The primary physical processes observed in this stress regime were material strength, porosity, and polymorphic phase transitions between the CaCO{sub 3} phases I, II, III and VI. Hydration was also a significant reaction under certain conditions. The Indiana Limestone studies in particular represent a significant addition to the low-pressure database for porous limestone. Temperature dependence and the effect of freezing were assessed for the Fort Knox limestone. Experimental parameters and detailed results are provided for the 42 impact tests in this series.

  9. Angular dependence of L X-rays emission for Ag by 10 keV electron-impact

    Wang, Xing; Xu, Zhongfeng; Zhang, Ying; Ma, Chao; Zhu, Chengwei

    2016-08-01

    The characteristic X-ray intensities of Ag-Lα, Lβ1, Lβ2 and Lγ1 are measured in electron-impact ionization at energy of 10 keV. The emission angle in this work ranges from 0° to 20° at interval of 5°. The angular dependence of L X-ray intensity ratios has been investigated for Lα / Lβ1, Lβ2 / Lβ1 and Lγ1 / Lβ1. It is found from the experimental results that the emissions of Lβ1, Lβ2 and Lγ1 X-rays are spatially isotropic, while the Lα X-rays exhibit anisotropic emission. Consequently, the alignment behavior of vacancy states is discussed with thorough analysis of vacancy transfer process.

  10. Cross section for induced L X-ray emission by protons of energy <400 keV

    Mohan, Harsh, E-mail: mohan_harsh@yahoo.com [Physics Department, M.L.N. College, Yamuna Nagar 135 001, Haryana (India); Jain, Arvind Kumar [Physics Department, M.L.N. College, Yamuna Nagar 135 001, Haryana (India); Kaur, Mandeep [Physics Department, M.L.N. College, Yamuna Nagar 135 001, Haryana (India); Physics Department, Punjabi University, Patiala 147 002, Punjab (India); Singh, Parjit S. [Physics Department, Punjabi University, Patiala 147 002, Punjab (India); Sharma, Sunita [Chemistry Department, M.L.N. College, Yamuna Nagar 135 001, Haryana (India)

    2014-08-01

    In performing ion beam analysis, cross section for induced L X-ray emission plays a crucial role. There are different approaches by which these can be found experimentally or can be calculated theoretically based on various models. L X-ray production cross sections for Bi with protons in the energy range 260–400 keV at the interval of 20 keV are measured. These are compared with calculations obtained on the basis of current prevailing theories ECPSSR and ECPSSR-UA. Their importance in understanding this phenomenon and existing arguments in this regard will be highlighted.

  11. Irradiation of biological molecules (DNA and RNA bases) by proton impact in the velocity range of the Bragg peak (20-150 keV/amu)

    The aim of this work was to study the ionization of DNA and RNA base molecules by proton impact at energies between 20 and 150 keV/amu. The experiments developed over the course of this project made it possible not only to study the fragmentation of uracil, thymine, adenine, and cytosine, but also to measure absolute cross sections for different ionization processes initiated by proton interactions with these important biological molecules. Firstly, the experimental system enabled the contributions of two key ionization processes to be separated: direct ionization and electron capture. The corresponding mass spectra were measured and analyzed on an event-by-event basis. For uracil, the branching ratios for these two processes were measured as function of the projectile velocity. Secondly, we have developed a system to measure absolute cross sections for the electron capture process. The production rate of neutral atoms compared to protons was measured for the four biological molecules: uracil, cytosine, thymine, and adenine at different vaporization temperatures. This production rate varies as a function of the thickness of the target jet traversed by the protons. Accordingly, a deposit experiment was developed in order to characterize the density of molecules in the targeted gas jets. Theoretical and experimental study of the total effusion and density-profile of the gaseous molecular beams enabled us to deduce the thickness of the target jets traversed by the protons. Thus it was possible to determine absolute cross sections for the ionization of each of the four isolated biological molecules by 80 keV protons impact. To our knowledge, this work provides the first experimental absolute cross sections for DNA and RNA base ionization processes initiated by proton impact in the velocity range corresponding to the Bragg peak. (author)

  12. LS1 Report: injectors 2.0

    Anaïs Schaeffer

    2014-01-01

    Launched in 2009, the Accelerator Controls Renovation Project (ACCOR) will come to an end this year. It was brought in to replace the approximately 450 real-time control systems of the LHC injector complex, some of which were based on technology more than 20 years old.   One of the approximately 450 real-time systems that have been modified in the ACCOR project. These systems, which use special software and thousands of electronics boards, control devices that are essential to the proper functioning of the injectors – the radiofrequency system, the instrumentation, the injection kicker system, the magnets, etc. – and some of them were no longer capable of keeping pace with the LHC. As a result, they urgently needed to be upgraded. "In 2009, after assessing the new technology available on the market, we signed contracts with Europe's most cutting-edge electronics manufacturers," explains Marc Vanden Eynden, ACCOR Project Leader. We then quickly m...

  13. Detection of 1 - 100 keV x-rays from high intensity, 500 fs laser- produced plasmas using charge-coupled devices

    Dunn, J.; Young, B.K.F.; Conder, A.D.; Stewart, R.E.

    1996-01-01

    We describe a compact, vacuum compatible, large format, charge- coupled device (CCD) camera for scientific imaging and detection of 1- 100 keV x rays in experiments at LLNL JANUS-1ps laser. A standard, front-illuminated, multi-pin phase device with 250 k electron full well capacity, low dark current (10 pA/cm{sup 2} at 20 C) and low read noise (5 electron rms) is cooled to -35 C to give the camera excellent 15-bit dynamic range and signal-to-noise response. Intensity and x-ray energy linear response were determined for optical and x-ray (<65 keV) photons and are in excellent agreement. Departure from linearity was less than 0.7%. Inherent linearity and energy dispersive characteristics of CCD cameras are well suited for hard x-ray photon counting. X-rays absorbed within the depletion and field-free regions can be distinguished by studying the pulse height spectrum. Results are presented for the detection of 1-100 keV Bremsstrahlung continuum, K-shell and L-shell fluorescence spectra emitted from high intensity (10{sup 18}W cm{sup -2}), 500 fs laser- produced plasmas.

  14. Heliospheric Neutral Atom Spectra Between 0.01 and 6 keV fom IBEX

    Fuselier, S. A.; Allegrini, F.; Bzowski, M.; Funsten, H. O.; Ghielmetti, A. G.; Gloeckler, G.; Heirtzler, D.; Janzen, P.; Kubiak, M.; Kucharek, H.; McComas, D. J.; Moebius, E.; Moore, T. E.; Petrinec, S. M.; Quinn, M.; Reisenfeld, D.; Saul, L. A.; Scheer, J. A.; Schwardron, N.; Trattner, K. J.; Vanderspek, R.; Wurz, P.

    2012-01-01

    Since 2008 December, the Interstellar Boundary Explorer (IBEX) has been making detailed observations of neutrals from the boundaries of the heliosphere using two neutral atom cameras with overlapping energy ranges. The unexpected, yet defining feature discovered by IBEX is a Ribbon that extends over the energy range from about 0.2 to 6 keV. This Ribbon is superposed on a more uniform, globally distributed heliospheric neutral population. With some important exceptions, the focus of early IBEX studies has been on neutral atoms with energies greater than approx. 0.5 keV. With nearly three years of science observations, enough low-energy neutral atom measurements have been accumulated to extend IBEX observations to energies less than approx. 0.5 keV. Using the energy overlap of the sensors to identify and remove backgrounds, energy spectra over the entire IBEX energy range are produced. However, contributions by interstellar neutrals to the energy spectrum below 0.2 keV may not be completely removed. Compared with spectra at higher energies, neutral atom spectra at lower energies do not vary much from location to location in the sky, including in the direction of the IBEX Ribbon. Neutral fluxes are used to show that low energy ions contribute approximately the same thermal pressure as higher energy ions in the heliosheath. However, contributions to the dynamic pressure are very high unless there is, for example, turbulence in the heliosheath with fluctuations of the order of 50-100 km/s.

  15. Web 2.0 and Social Software

    Ryberg, Thomas

    2006-01-01

    Presentation given at the MINE workshop - a 2-day workshop for students to create innovative products to be presented to the public during Culture Night 13th of October......Presentation given at the MINE workshop - a 2-day workshop for students to create innovative products to be presented to the public during Culture Night 13th of October...

  16. 20 CFR 302.2 - Definitions.

    2010-04-01

    ... tax base under section 3231(e)(2) of the Internal Revenue Code for the calendar year for which the... EMPLOYEE § 302.2 Definitions. Base year. The term “base year” means the completed calendar year immediately... monthly compensation base for that month and also excluding payments of the character described in §...

  17. 41 CFR 60-20.2 - Recruitment and advertisement.

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Recruitment and advertisement. 60-20.2 Section 60-20.2 Public Contracts and Property Management Other Provisions Relating to Public Contracts OFFICE OF FEDERAL CONTRACT COMPLIANCE PROGRAMS, EQUAL EMPLOYMENT OPPORTUNITY, DEPARTMENT OF LABOR 20-SEX DISCRIMINATION GUIDELINES...

  18. Ellipsometry and energy characterization of the electron impact polymerization in the range 0-20 eV

    Zyn, V. I.

    2016-05-01

    The electron impact polymerization of adsorbed vapors of a hydrocarbon vacuum oil with molecular mass 450 Da (C32H66) has been studied in-situ in the range 0-20 eV using ellipsometry and a servo system with the Kelvin's vibrating probe. This allowed registering at the same time the two energy-dependent characteristics (spectra) of the process: the film growth rate and the electrical potential of the irradiated surface. The first spectrum has two resonance maxima near 2.5 and 9.5 eV while the surface potential has only one weak extremum near 9.5 eV. The first growth rate peak at 2.5 eV was connected with a creation of radicals through a resonant process of the dissociative electron attachment and beginning polymerization. The peaks at 9.5 eV in both the spectra mean accelerating polymerization and decreasing surface charge owing to simultaneous birth of highly active radicals and free electrons. The single resonant process controlling both the processes simultaneously is the dissociative attachment of an electron to an anti-bonding molecular orbital, almost the same as at the 2.5 eV but differing by deeper decomposition of the transient anion, among the products of which are now not the radicals only but also free electrons. The kinetic curves obtained in pulsed regimes of the electron bombardment were qualitatively identical for different precursors and were used for calculations of cross sections of these processes.

  19. Parrot AR.Drone 2.0

    2012-01-01

    Parrot AR.Drone 2.0是极客们的超级玩具。它搭载Wi-Fi功能,可以用智能手机遥控。上面的摄像头能够实时将采集的画面发送到iOS或Android设备上。Parrot AR.Drone 2.0比前辈技巧更强。你会对它爱不释手……

  20. Effects of the compounds 2-methoxynaphthoquinone, 2-propoxynaphthoquinone, and 2-isopropoxynaphthoquinone on ecdysone 20-monooxygenase activity.

    Mitchell, Martin J; Brescia, Aaron I; Smith, Stan L; Morgan, E David

    2007-09-01

    The effects of the natural compound 2-methoxy-1,4-naphthoquinone, isolated from the leaves of Impatiens glandulifera and the synthetic compounds 2-propoxy-1,4-naphthoquinone and 2-isopropoxy-1,4-naphthoquinone on ecdysone 20-monooxygenase (E-20-M) activity were examined in three insect species. Homogenates of wandering stage third instar larvae of Drosophila melanogaster, or abdomens from adult female Aedes aegypti, or fat body or midgut from fifth instar larvae of Manduca sexta were incubated with radiolabelled ecdysone and increasing concentrations (from 1 x 10(-8) to 1 x 10(-3) M) of the three compounds. All three compounds were found to inhibit in a dose-dependent fashion the E-20-M activity in the three insect species. The concentration of these compounds required to elicit a 50% inhibition of this steroid hydroxylase activity in the three insect species examined ranged from approximately 3 x 10(-5) to 7 x 10(-4) M. PMID:17694563

  1. Mobility2.0: co-operative ITS systems for enhanced electric vehicle mobility

    Heijenk, G.; Dimitrova, D.C.; Brogle, M.; Braun, T.; Heijenk, G.J.

    2013-01-01

    Mobility2.0 will develop and test an in-vehicle commuting assistant for FEV mobility, resulting in more reliable and energy-efficient electro-mobility. In order to achieve a maximum impact, Mobility2.0 takes an integrated approach of ad- dressing the main bottlenecks of urban FEV mobility: range anx

  2. The Web 2.0 as Marketing Tool: Opportunities for SMEs

    Constantinides, Efthymios

    2008-01-01

    The new generation of Internet applications widely known as Social Media or Web 2.0 offers corporations a whole range of opportunities for improving their marketing efficiency and internal operations. Web 2.0 applications have already become part of the daily life of an increasing number of consumer

  3. Large Range Manipulation of Exciton Species in Monolayer WS2

    Wei, Ke; Yang, Hang; Cheng, Xiangai; Jiang, Tian

    2016-01-01

    Unconventional emissions from exciton and trion in monolayer WS2 are studied by photoexcitation. Excited by 532nm laser beam, the carrier species in the monolayer WS2 are affected by the excess electrons escaping from photoionization of donor impurity, the concentration of which varies with different locations of the sample. Simply increasing the excitation power at room temperature, the excess electron and thus the intensity ratio of excited trion and exciton can be continuously tuned over a large range from 0.1 to 7.7. Furthermore, this intensity ratio can also be manipulated by varying temperature. However, in this way the resonance energy of the exciton and trion show red-shifts with increasing temperature due to electron-phonon coupling. The binding energy of the trion is determined to be ~23meV and independent to temperature, indicating strong Coulomb interaction of carriers in such 2D materials.

  4. Birding 2.0: Citizen Science and Effective Monitoring in the Web 2.0 World

    Yolanda F. Wiersma

    2010-12-01

    Full Text Available The amateur birding community has a long and proud tradition of contributing to bird surveys and bird atlases. Coordinated activities such as Breeding Bird Atlases and the Christmas Bird Count are examples of "citizen science" projects. With the advent of technology, Web 2.0 sites such as eBird have been developed to facilitate online sharing of data and thus increase the potential for real-time monitoring. However, as recently articulated in an editorial in this journal and elsewhere, monitoring is best served when based on a priori hypotheses. Harnessing citizen scientists to collect data following a hypothetico-deductive approach carries challenges. Moreover, the use of citizen science in scientific and monitoring studies has raised issues of data accuracy and quality. These issues are compounded when data collection moves into the Web 2.0 world. An examination of the literature from social geography on the concept of "citizen sensors" and volunteered geographic information (VGI yields thoughtful reflections on the challenges of data quality/data accuracy when applying information from citizen sensors to research and management questions. VGI has been harnessed in a number of contexts, including for environmental and ecological monitoring activities. Here, I argue that conceptualizing a monitoring project as an experiment following the scientific method can further contribute to the use of VGI. I show how principles of experimental design can be applied to monitoring projects to better control for data quality of VGI. This includes suggestions for how citizen sensors can be harnessed to address issues of experimental controls and how to design monitoring projects to increase randomization and replication of sampled data, hence increasing scientific reliability and statistical power.

  5. NASA Taxonomy 2.0 Project Overview

    Dutra, Jayne; Busch, Joseph

    2004-01-01

    This viewgraph presentation reviews the project to develop a Taxonomy for NASA. The benefits of this project are: Make it easy for various audiences to find relevant information from NASA programs quickly, specifically (1) Provide easy access for NASA Web resources (2) Information integration for unified queries and management reporting ve search results targeted to user interests the ability to move content through the enterprise to where it is needed most (3) Facilitate Records Management and Retention Requirements. In addition the project will assist NASA in complying with E-Government Act of 2002 and prepare NASA to participate in federal projects.

  6. High Optical Access Trap 2.0.

    Maunz, Peter Lukas Wilhelm [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-26

    The High Optical Access (HOA) trap was designed in collaboration with the Modular Universal Scalable Ion-trap Quantum Computer (MUSIQC) team, funded along with Sandia National Laboratories through IARPA's Multi Qubit Coherent Operations (MQCO) program. The design of version 1 of the HOA trap was completed in September 2012 and initial devices were completed and packaged in February 2013. The second version of the High Optical Access Trap (HOA-2) was completed in September 2014 and is available at IARPA's disposal.

  7. SOURCE 2.0 model development: UO2 thermal properties

    During analysis of CANDU postulated accidents, the reactor fuel is estimated to experience large temperature variations and to be exposed to a variety of environments from highly oxidized to mildly reducing. The exposure of CANDU fuel to these environments and temperatures may affect fission product releases from the fuel and cause degradation of the fuel thermal properties. The SOURCE 2.0 project is a safety analysis code which will model the necessary mechanisms required to calculate fission product release for a variety of accident scenarios, including large break loss of coolant accidents (LOCAs) with or without emergency core cooling. The goal of the model development is to generate models which are consistent with each other and phenomenologically based, insofar as that is possible given the state of theoretical understanding

  8. Analysis of the TMI-2 source range detector response

    In the first few hours following the TMI-2 accident large variations (factors of 10-100) in the source range (SR) detector response were observed. The purpose of this analysis was to quantify the various effects which could contribute to these large variations. The effects evaluated included the transmission of neutrons and photons from the core to detector and the reduction in the multiplication of the Am-Be startup sources, and subsequent reduction in SR detector response, due to core voiding. A one-dimensional ANISN slab model of the TMI-2 core, core externals, pressure vessel and containment has been constructed for calculation of the SR detector response and is presented

  9. BioCat 2.0

    Corley, Courtney D.; Noonan, Christine F.; Bartholomew, Rachel A.; Franklin, Trisha L.; Hutchison, Janine R.; Lancaster, Mary J.; Madison, Michael C.; Piatt, Andrew W.

    2013-09-16

    The U.S. Department of Homeland Security (DHS) National Biosurveillance Integration Center (NBIC) was established in 2008 with a primary mission to “(1) enhance the capability of the Federal Government to (A) rapidly identify, characterize, localize, and track a biological event of national concern by integrating and analyzing data relating to human health, animal, plant, food, and environmental monitoring systems (both national and international); and (B) disseminate alerts and other information to Member Agencies and, in coordination with (and where possible through) Member Agencies, to agencies of State, local, and tribal governments, as appropriate, to enhance the ability of such agencies to respond to a biological event of national concern; and (2) oversee development and operation of the National Biosurveillance Integration System (NBIS).” Inherent in its mission then and the broader NBIS, NBIC is concerned with the identification, understanding, and use of a variety of biosurveillance models and systems. The goal of this project is to characterize, evaluate, classify, and catalog existing disease forecast and prediction models that could provide operational decision support for recognizing a biological event having a potentially significant impact. Additionally, gaps should be identified and recommendations made on using disease models in an operational environment to support real-time decision making.

  10. Web 2.0 Learning Environment: Concept, Implementation, Evaluation

    Blees, Ingo; Rittberger, Marc

    2009-01-01

    This contribution presents and evaluates a new learning environment model based on Web 2.0 applications. In a theoretical overview the concepts of eLearning 2.0 and Personal Learning Environments are introduced, along with their main aspects of autonomy, creativity and networking, and relate them to the didactics of constructivism and connectivism. The requirements and basic functional components for the development of our particular Web 2.0 learning environment are derived from these. The le...

  11. Marketing 2.0: A new marketing strategy

    Domenico CONSOLI; Musso, Fabio

    2010-01-01

    The advent of Web 2.0 and its collaborative tools (forums, chat, blogs, wikis) simplified the interaction among various business subjects (company, customers, suppliers). A new model of Enterprise 2.0 communicates interactively with all stakeholders, cooperate with them, listen, create, share and capitalize knowledge. Web 2.0 enhances customer relationships and supports, fully, developments in the field of marketing: from advertisement to participation, from social networking to mobile comm...

  12. Web 2.0: Where does Europe stand?

    Lindmark, Sven

    2009-01-01

    This report provides a techno-economic analysis of Web 2.0 and an assessment of Europe's position in Web 2.0 applications. Firstly, it introduces the phenomenon of Web 2.0 and its main characteristics: technologies, applications, and user roles. It then provides an overview of its adoption, value chain and business models, before moving to an analysis of its drivers, industrial impact and disruptive potential. Finally, the report assesses the position of the European Web 2.0 applications indu...

  13. Are People Really Social on Porn 2.0?

    Tyson, Gareth; Elkhatib, Yehia; Sastry, Nishanth; Uhlig, Steve

    2015-01-01

    Social Web 2.0 features have become a vital component in a variety of multimedia systems, e.g., Last.fm, Flickr and Spotify. Interestingly, adult video websites are also starting to adopt these Web 2.0 principles, giving rise to the term ``Porn 2.0''. This paper examines a large Porn 2.0 social network, through data covering 563k users. We explore a number of unusual behavioural aspects that set this apart from more traditional multimedia social networks, including differences in browsing act...

  14. OAuth 2.0 identity and access management patterns

    Spasovski, Martin

    2013-01-01

    This is a practical and fast-paced guide that gives you all the information you need to start implementing secure OAuth 2.0 implementations in your web applications.OAuth 2.0 Identity and Access Management Patterns is intended for software developers, software architects, and enthusiasts working with the OAuth 2.0 framework.In order to learn and understand the OAuth 2.0 grant flow, it is assumed that you have some basic knowledge of HTTP communication. For the practical examples, basic knowledge of HTML templating, programming languages, and executing commands in the command line terminal is a

  15. Er Web 2.0 klar til mainstream?

    Ivang, Reimer

    2009-01-01

    BLOG: Spørgsmålene der relateres til Web 2.0 er mange. Men en af de mest signifikante er om netop din virksomhed skal anvende Web 2.0 teknologier? Hvad kan I få ud af det?......BLOG: Spørgsmålene der relateres til Web 2.0 er mange. Men en af de mest signifikante er om netop din virksomhed skal anvende Web 2.0 teknologier? Hvad kan I få ud af det?...

  16. Web 2.0 for social learning in higher education

    Nicolajsen, Hanne Westh

    2011-01-01

    The use of Web 2.0 in higher education provides for a number of different possibilities. In this paper we look into the use of Web 2.0 as a platform for social learning supplementing traditional teaching methods such as lectures and on place group work. The findings are astonishing revealing...... challenges such as the unknown genre of Web 2.0 for learning and changed behaviors with relevance for the identity creation and perception of others. The insight points to a number of issues of relevance when Web 2.0 is integrated in design for learning....

  17. Electron impact total cross sections for simple biomolecules (HCOOH and H2CO) over a wide energy range (meV to keV)

    We present here total cross sections obtained as sum of elastic and electronic excitation cross sections below ionization threshold of the target and sum of elastic and inelastic cross sections above ionization threshold molecule. We employ two different codes, R matrix code through Quantemol N for low energies and Spherical Complex Optical Potential for intermediate and high energies.

  18. Evaluating HDR photos using Web 2.0 technology

    Qiu, Guoping; Mei, Yujie; Duan, Jiang

    2011-01-01

    High dynamic range (HDR) photography is an emerging technology that has the potential to dramatically enhance the visual quality and realism of digital photos. One of the key technical challenges of HDR photography is displaying HDR photos on conventional devices through tone mapping or dynamic range compression. Although many different tone mapping techniques have been developed in recent years, evaluating tone mapping operators prove to be extremely difficult. Web2.0, social media and crowd-sourcing are emerging Internet technologies which can be harnessed to harvest the brain power of the mass to solve difficult problems in science, engineering and businesses. Paired comparison is used in the scientific study of preferences and attitudes and has been shown to be capable of obtaining an interval-scale ordering of items along a psychometric dimension such as preference or importance. In this paper, we exploit these technologies for evaluating HDR tone mapping algorithms. We have developed a Web2.0 style system that enables Internet users from anywhere to evaluate tone mapped HDR photos at any time. We adopt a simple paired comparison protocol, Internet users are presented a pair of tone mapped images and are simply asked to select the one that they think is better or click a "no difference" button. These user inputs are collected in the web server and analyzed by a rank aggregation algorithm which ranks the tone mapped photos according to the votes they received. We present experimental results which demonstrate that the emerging Internet technologies can be exploited as a new paradigm for evaluating HDR tone mapping algorithms. The advantages of this approach include the potential of collecting large user inputs under a variety of viewing environments rather than limited user participation under controlled laboratory environments thus enabling more robust and reliable quality assessment. We also present data analysis to correlate user generated qualitative

  19. Combining 2-m temperature nowcasting and short range ensemble forecasting

    A. Kann

    2011-12-01

    Full Text Available During recent years, numerical ensemble prediction systems have become an important tool for estimating the uncertainties of dynamical and physical processes as represented in numerical weather models. The latest generation of limited area ensemble prediction systems (LAM-EPSs allows for probabilistic forecasts at high resolution in both space and time. However, these systems still suffer from systematic deficiencies. Especially for nowcasting (0–6 h applications the ensemble spread is smaller than the actual forecast error. This paper tries to generate probabilistic short range 2-m temperature forecasts by combining a state-of-the-art nowcasting method and a limited area ensemble system, and compares the results with statistical methods. The Integrated Nowcasting Through Comprehensive Analysis (INCA system, which has been in operation at the Central Institute for Meteorology and Geodynamics (ZAMG since 2006 (Haiden et al., 2011, provides short range deterministic forecasts at high temporal (15 min–60 min and spatial (1 km resolution. An INCA Ensemble (INCA-EPS of 2-m temperature forecasts is constructed by applying a dynamical approach, a statistical approach, and a combined dynamic-statistical method. The dynamical method takes uncertainty information (i.e. ensemble variance from the operational limited area ensemble system ALADIN-LAEF (Aire Limitée Adaptation Dynamique Développement InterNational Limited Area Ensemble Forecasting which is running operationally at ZAMG (Wang et al., 2011. The purely statistical method assumes a well-calibrated spread-skill relation and applies ensemble spread according to the skill of the INCA forecast of the most recent past. The combined dynamic-statistical approach adapts the ensemble variance gained from ALADIN-LAEF with non-homogeneous Gaussian regression (NGR which yields a statistical mbox{correction} of the first and second moment (mean bias and dispersion for Gaussian distributed continuous

  20. Determination of the mean energy needed for the creation of an ionpair for hydrogen- and helium ions in different gases with energy in the range 95-1110 keV

    As a result of the studies of N, CO2 and CH4, with decreasing energy of the primary ions a strong increase in the W-values has been found for He-ions. This increase is four times stronger as in the case of H-ions. For tissue equivalent gases the W-values can be determined from the different gas constituents by a mixing calculation. A special ionisation chamber set-up has been used for the present studies, including a monitoring system for the primary beam. (DG)

  1. One-sided imaging of large, dense objects using the 511 keV photons from induced pair production

    Tavora, L.M.; Gilboy, W.B.; Morton, E.J. [Univ. of Surrey, Guildford (United Kingdom). Physics Dept.; Morgado, R.E.; Estep, R.J.; Rawool-Sullivan, M. [Los Alamos National Lab., NM (United States)

    1998-03-01

    The use of annihilation photons from photon-induced electron-positron pair production as a means of inspecting objects when only one side is accessible is described. The Z2 dependence of the pair production cross section and the high penetration of 511 keV photons suggest that this method should be capable of localizing high Z materials in lower Z matrices. The experimental results for the dependence of the back streaming photon yield on Z indicate that dynamic ranges of the order of 20 may be obtained for materials with 4 < Z < 82. Results for point to point images obtained in line scans of representative geometries are also shown. Simulation studies based on the EGS4 Monte Carlo code were also performed and their results show an agreement with experimental data of the order of 5%.

  2. One-sided imaging of large, dense objects using the 511 keV photons from induced pair production

    The use of annihilation photons from photon-induced electron-positron pair production as a means of inspecting objects when only one side is accessible is described. The Z2 dependence of the pair production cross section and the high penetration of 511 keV photons suggest that this method should be capable of localizing high Z materials in lower Z matrices. The experimental results for the dependence of the back streaming photon yield on Z indicate that dynamic ranges of the order of 20 may be obtained for materials with 4 < Z < 82. Results for point to point images obtained in line scans of representative geometries are also shown. Simulation studies based on the EGS4 Monte Carlo code were also performed and their results show an agreement with experimental data of the order of 5%

  3. The double ionisation of hydrogen by 5-30 keV protons

    The energy and angular distribution of pairs of fragment protons produced in H+-H2 collisions has been investigated in the energy range 5-30 keV. It is shown that the energy distribution is a simple transformation of the ground-state wavefunction of H2 and an experimental determination of the ground-state probability density distribution is presented. Total and differential double ionisation cross sections are found to be in accord with earlier measurements. (author)

  4. Brillouin spectroscopic investigations of LiKSO4 in the temperature range from 20 to 150 K

    Brillouin spectroscopy has been used to determine the temperature dependence of the velocity of longitudinal acoustic modes in a lithium-potassium sulphate single crystal in the temperature range from 20 to 150 K. Small anomalies were recorded for the modes propagating in [101] and [011] directions. The frequency of the [100] mode is practically temperature independent. The velocity of the [001] mode shows a minimum (relative change, 4.5%) at 52 K which corresponds to the known phase transition temperature in this crystal. The results of two sequential runs performed on the same sample (thermal cycling) are compared and discussed. (author)

  5. The T2K Side Muon Range Detector (SMRD)

    The T2K experiment is a long baseline neutrino oscillation experiment aiming to observe the appearance of νe in a νμ beam. The νμ beam is produced at the Japan Proton Accelerator Research Complex (J-PARC), observed with the 295 km distant Super-Kamiokande Detector and monitored by a suite of near detectors at 280 m from the proton target. The near detectors include a magnetized off-axis detector (ND280) which measures the unoscillated neutrino flux and neutrino cross-sections. The present paper describes the outermost component of ND280 which is a Side Muon Range Detector (SMRD) composed of scintillation counters with embedded wavelength shifting fibers and Multi-Pixel Photon Counter readout. The components, performance and response of the SMRD are presented.

  6. Photon emission from clean and oxygenated Si and SiO2 surfaces bombarded by 5 keV krypton ions

    The effect of oxygen on the light emission from a Si (1 0 0) semiconductor bombarded by energetic Kr+ ions has been studied in the 200-300 nm wavelength range. The influence of oxygen was verified by studying the optical spectra of SiO2 bombarded under similar experimental conditions. It has been found that the measured intensities of the emitted photons are always higher in the presence of oxygen, even higher than those obtained for SiO2. The electron-transfer model can explain our experimental observations. We do believe that in the presence of oxygen, an intermediate structure of silicon sub-oxide SiOX is formed on silicon surface, which is responsible for the increase of photon emission. In addition, the radiative dissociation process and breaking of chemical bond seems contribute to the enhancement of emitted photons intensity.

  7. Using Web 2.0 for health promotion and social marketing efforts: lessons learned from Web 2.0 experts.

    Dooley, Jennifer Allyson; Jones, Sandra C; Iverson, Don

    2014-01-01

    Web 2.0 experts working in social marketing participated in qualitative in-depth interviews. The research aimed to document the current state of Web 2.0 practice. Perceived strengths (such as the viral nature of Web 2.0) and weaknesses (such as the time consuming effort it took to learn new Web 2.0 platforms) existed when using Web 2.0 platforms for campaigns. Lessons learned were identified--namely, suggestions for engaging in specific types of content creation strategies (such as plain language and transparent communication practices). Findings present originality and value to practitioners working in social marketing who want to effectively use Web 2.0. PMID:24878406

  8. Variable range hopping in TiO2 insulating layers for oxide electronic devices

    Y. L. Zhao

    2012-03-01

    Full Text Available TiO2 thin films are of importance in oxide electronics, e.g., Pt/TiO2/Pt for memristors and Co-TiO2/TiO2/Co-TiO2 for spin tunneling devices. When such structures are deposited at a variety of oxygen pressures, how does TiO2 behave as an insulator? We report the discovery of an anomalous resistivity minimum in a TiO2 film at low pressure (not strongly dependent on deposition temperature. Hall measurements rule out band transport and in most of the pressure range the transport is variable range hopping (VRH though below 20 K it was difficult to differentiate between Mott and Efros-Shklovskii's (ES mechanism. Magnetoresistance (MR of the sample with lowest resistivity was positive at low temperature (for VRH but negative above 10 K indicating quantum interference effects.

  9. Primary Discussions of e-Learning 2.0%e-Learning 2.0初探

    刘革平; 李倩

    2009-01-01

    理论与技术的进步给e-Learning带来了发展和变革的机会.本文在阐述Web 2.0与e-Learning关系的基础上引入了e-Learning 2.0的概念.文中讨论了e-Learning 2.0的本质特征并给出了其含义的界定.最后论述了e-Learning 2.0的理论基础.

  10. Ubiquitous Complete in a Web 2.0 World

    Bull, Glen; Ferster, Bill

    2006-01-01

    In the third wave of computing, people will interact with multiple computers in multiple ways in every setting. The value of ubiquitous computing is enhanced and reinforced by another trend: the transition to a Web 2.0 world. In a Web 2.0 world, applications and data reside on the Web itself. Schools are not yet approaching a ratio of one…

  11. Students as Digital Citizens on Web 2.0

    Nebel, Michelle; Jamison, Barbara; Bennett, Linda

    2009-01-01

    Internet tools associated with Web 2.0 such as wikis, blogs, and video podcasts are increasingly available in elementary classrooms. ("Web 2.0" is a vaguely defined, folk-tech term that means, roughly, the Internet and all software and devices, constantly improving, that strive to exploit it in creative and useful ways.) Today, elementary students…

  12. Web 2.0: Creating a Classroom without Walls

    Barlow, Tim

    2008-01-01

    This article is about my year-long journey implementing Web 2.0 tools into my teaching practice. The goal throughout my journey has always been to increase my students' intrinsic motivation to learn about science. The Web 2.0 tools I used along my journey were weblogs (blogs) and podcasts. (Contains 1 figure.)

  13. 26 CFR 20.7520-2 - Valuation of charitable interests.

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Valuation of charitable interests. 20.7520-2... Valuations § 20.7520-2 Valuation of charitable interests. (a) In general—(1) Valuation. Except as otherwise... applicable section 7520 interest rate. If the executor elects the alternate valuation date under section...

  14. How to use web 2.0 in your library

    Bradley, Phil

    2007-01-01

    The Web 2.0 and social software explosion has the capability to transform the online profile of libraries and help reach out to tech-savvy young users to whom the library may be invisible. This title explains how to use the different types of Web 2.0 technologies, and, using examples, shows how libraries can get the most out of them.

  15. NOAA-CIRES 20th Century Reanalysis (V2c)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 20th Century Reanalysis version 2c (20CRV2c)is an effort led by PSD and the CIRES at the University of Colorado to produce a reanalysis dataset spanning the...

  16. Web 2.0: Conceptual foundations and marketing issues

    Constantinides, Efthymios; Fountain, Stefan J.

    2008-01-01

    This paper identifies the technological and commercial foundations of the new category of online applications commonly described as Web 2.0 or Social Media. It examines the relevance of Web 2.0 for Marketing Strategy and for Direct Marketing in particular. The issue is not a clear-cut one: while sev

  17. A Framework for Web 2.0 Learning Design

    Bower, Matt; Hedberg, John G.; Kuswara, Andreas

    2010-01-01

    This paper describes an approach to conceptualising and performing Web 2.0-enabled learning design. Based on the Technological, Pedagogical and Content Knowledge model of educational practice, the approach conceptualises Web 2.0 learning design by relating Anderson and Krathwohl's Taxonomy of Learning, Teaching and Assessing, and different types…

  18. Unleashing the Power of Web 2.0

    Waters, John K.

    2008-01-01

    As Web 2.0 technologies impact the evolution of online learning, they are certain to blur the definitional lines between electronic portfolios and personal learning environments (PLEs). According to Gary Brown, director of Washington State University's Center for Teaching, Learning, and Technology, the Web 2.0 technologies that are emerging…

  19. Driving Web 2.0 Tool Adoption in Agricultural Education

    Constantina Costopouloul

    2013-04-01

    Full Text Available The new opportunities for collaboration, participatory content creation and communication offered through the advancements of Web 2.0, such as social networking, blogs, wikis, video sharing and other, are creating new learning models. In turn, tutors cannot ignore this trend and have to bear the responsibility of incorporating Web 2.0 tools in formal, informal, work-based and vocational education and approach their students in a very familiar and favourable way. In this context, this paper tries to highlight the need for enhancing tutors’ skills and drive Web 2.0 tool adoption in educational practice. Thus, it draws upon the successful example of a European project regarding agricultural tutors’ training on Web 2.0 tools. The challenge for all agricultural tutors is how to integrate Web 2.0 tools into current curricula and education.

  20. Enabling Problem Based Learning through Web 2.0 Technologies

    Tambouris, Efthimios; Panopoulou, Eleni; Tarabanis, Konstantinos;

    2012-01-01

    Advances in Information and Communications Technology (ICT), particularly the so-called Web 2.0, are affecting all aspects of our life: how we communicate, how we shop, how we socialise, and how we learn. Facilitating learning through the use of ICT, also known as eLearning, is a vital part of...... modern educational systems. Established pedagogical strategies, such as Problem Based Learning (PBL), are being adapted for online use in conjunction with modern Web 2.0 technologies and tools. However, even though Web 2.0 and progressive social-networking technologies are automatically associated with...... ideals such as collaboration, sharing, and active learning, it is also possible to use them in a very conservative, teacher-centred way limiting thus their impact. In this paper, we present a PBL 2.0 framework, i.e., a framework combining PBL practices with Web 2.0 technologies. More specifically, we (a...

  1. Measurement of the bremsstrahlung spectra generated from thick targets with =2–78 under the impact of 10 keV electrons

    Namita Yadav; Pragya Bhatt; Raj Singh; V S Subrahmanyam; R Shanker

    2010-04-01

    We present new experimental data on thick target bremsstrahlung spectra generated from the interaction of energetic electrons with bulk matter. The ‘photon yields’ in terms of double differential cross-sections (DDCS) are measured for pure elements of thick targets: Ti ( = 22), Ag ( = 47), W ( = 74) and Pt ( = 78) under the impact of 10 keV electrons. Comparison of DDCS obtained from the experimental data is made with those predicted by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the experimental data and the MC calculations is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty of about 10% and they are compared with MC calculations. A satisfactory agreement is found between the experiment and the calculations within some normalizing factors. The variations of DDCS as a function of Z and of photon energy are also studied which show that the DDCS vary closely with Z; however, some deviations are observed for ‘tip’ photons emitted from high Z targets.

  2. Efficient focusing of 8 keV X-rays with multilayer Fresnel zone plates fabricated by atomic layer deposition and focused ion beam milling

    Mayer, Marcel; Keskinbora, Kahraman; Grévent, Corinne, E-mail: grevent@is.mpg.de [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Szeghalmi, Adriana [Friedrich-Schiller-Universität Jena, Albert-Einstein-Strasse 15, D-07745 Jena (Germany); Knez, Mato [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, E-20018 Donostia-San Sebastian (Spain); Basque Foundation for Science, Alameda Urquijo 36-5, E-48011 Bilbao (Spain); Weigand, Markus [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Snigirev, Anatoly; Snigireva, Irina [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble (France); Schütz, Gisela [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart (Germany)

    2013-05-01

    The fabrication and performance of multilayer Al{sub 2}O{sub 3}/Ta{sub 2}O{sub 5} Fresnel zone plates in the hard X-ray range and a discussion of possible future developments considering available materials are reported. Fresnel zone plates (FZPs) recently showed significant improvement by focusing soft X-rays down to ∼10 nm. In contrast to soft X-rays, generally a very high aspect ratio FZP is needed for efficient focusing of hard X-rays. Therefore, FZPs had limited success in the hard X-ray range owing to difficulties of manufacturing high-aspect-ratio zone plates using conventional techniques. Here, employing a method of fabrication based on atomic layer deposition (ALD) and focused ion beam (FIB) milling, FZPs with very high aspect ratios were prepared. Such multilayer FZPs with outermost zone widths of 10 and 35 nm and aspect ratios of up to 243 were tested for their focusing properties at 8 keV and shown to focus hard X-rays efficiently. This success was enabled by the outstanding layer quality thanks to ALD. Via the use of FIB for slicing the multilayer structures, desired aspect ratios could be obtained by precisely controlling the thickness. Experimental diffraction efficiencies of multilayer FZPs fabricated via this combination reached up to 15.58% at 8 keV. In addition, scanning transmission X-ray microscopy experiments at 1.5 keV were carried out using one of the multilayer FZPs and resolved a 60 nm feature size. Finally, the prospective of different material combinations with various outermost zone widths at 8 and 17 keV is discussed in the light of the coupled wave theory and the thin-grating approximation. Al{sub 2}O{sub 3}/Ir is outlined as a promising future material candidate for extremely high resolution with a theoretical efficiency of more than 20% for as small an outermost zone width as 10 nm at 17 keV.

  3. Quantum Model for Information Retrieval in Web 2.0

    Mohammad Bagher Negahban

    2014-06-01

    Full Text Available The study deals with the possibility of information loss in Web 2.0 due to the interaction between the overload and the real information. Using Gottesman and Preskill method, this investigation has proposed a mechanism to calculate the amount of information transformation in Web 2.0. In this proposal, there are three different Hilbert spaces that belong to the degrees of freedom of outside, inside, and overload information of Web 2.0. The information transformation in Web 2.0 is described at two stages. At the first stage, it is shown that the internal stationary state of Web 2.0 can be represented by a maximally entangled two-mode squeezed state of inside and overload information. At the second stage, the state of Web 2.0. is described by a maximally entangled two-mode squeezed state of overload and outside information. The amount of information transformation can be obtained by projecting the state at the first stage on the state at the second stage. Evidently, this study concludes that the information is not lost in Web 2.0.

  4. Calculation for Improvement of 350 keV Electron Accelerator

    2011-01-01

    The main problem of the 350 keV electric accelerator is that the accelerator can not output 20 mA for a long time otherwise the vacuum become bad. The reason is that part of the beam bomb on the scanning box and increase the temperature immediately,

  5. Search for admixture of heavy neutrinos with masses between 5 and 55 keV

    Markey, J.; Boehm, F.

    1985-01-01

    Using a magnetic spectrometer at a momentum resolution of 0.3%, we have studied the beta spectrum from 35S. We do not see evidence for the admixture of a heavy neutrino to the usual light (m~0) ν̃e accompanying beta decay, in the mass range between 5 and 50 keV, with a limit for the mixing strength of |U|2

  6. Extreme energetic electron fluxes in low Earth orbit: Analysis of POES E > 30, E > 100, and E > 300 keV electrons

    Meredith, Nigel P.; Horne, Richard B.; Isles, John D.; Green, Janet C.

    2016-02-01

    Energetic electrons are an important space weather hazard. Electrons with energies less than about 100 keV cause surface charging, while higher-energy electrons can penetrate materials and cause internal charging. In this study we conduct an extreme value analysis of the maximum 3-hourly flux of E > 30 keV, E > 100 keV, and E > 300 keV electrons in low Earth orbit as a function of L∗, for geomagnetic field lines that map to the outer radiation belt, using data from the National Oceanic and Atmospheric Administration Polar Operational Environmental Satellites (POES) from July 1998 to June 2014. The 1 in 10 year flux of E > 30 keV electrons shows a general increasing trend with distance ranging from 1.8 × 107 cm-2 s-1 sr-1 at L∗=3.0 to 6.6 × 107 cm-2 s-1 sr-1 at L∗=8.0. The 1 in 10 year flux of E > 100 keV electrons peaks at L∗=4.5-5.0 at 1.9 × 107 cm-2 s-1 sr-1 decreasing to minima of 7.1 × 106 and 8.7 × 106 cm-2 s-1 sr-1 at L∗=3.0 and 8.0, respectively. In contrast to the E > 30 keV electrons, the 1 in 10 year flux of E > 300 keV electrons shows a general decreasing trend with distance, ranging from 2.4 × 106 cm-2 s-1 sr-1 at L∗=3.0 to 1.2 × 105 cm-2 s-1 sr-1 at L∗=8.0. Our analysis suggests that there is a limit to the E > 30 keV electrons with an upper bound in the range 5.1 × 107 to 8.8 × 107 cm-2 s-1 sr-1. However, the results suggest that there is no upper bound for the E > 100 keV and E > 300 keV electrons.

  7. Online Reputation Systems in Web 2.0 Era

    Zheng, Weijun; Jin, Leigh

    Web 2.0 has transformed how reputation systems are designed and used by the Web. Based on a thorough review of the existing online reputation systems and their challenges in use, this paper studied a case of Amazon’s reputation system for the impacts of Web 2.0. Through our case study, several distinguished features of new generation reputation systems are noted including multimedia feedbacks, reviewer centered, folksonomy, community contribution, comprehensive reputation, dynamic and interactive system etc. These new developments move towards a relatively trustworthy and reliable online reputation system in the Web 2.0 era.

  8. Adoption of Web 2.0 tools in distance education

    Yasemin Koçak Usluel; Sacide Güzin Mazman

    2009-01-01

    This study has two purposes. First is to explain possible educational utilization of Web 2.0 tools, namely blogs, wikis, podcasts and social networks, from the point of importance of interaction for distance education. The second purpose of this study is to investigate adoption process of Web 2.0 tools in distance education by defining theories and models which have different construct that effect this process. Because the nature and structure of both distance education and Web 2.0 include mu...

  9. r-Java 2.0: the astrophysics

    Kostka, M.; N. Koning; Shand, Z.; Ouyed, R.; Jaikumar, P.

    2014-01-01

    [Context:] This article is the second in a two part series introducing r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations and provides a suite of other analysis tools. [Aims:] The first paper discussed the nuclear physics inherent to r-Java 2.0 and in this article the astrophysics incorporated into the software will be detailed. [Methods:] R-Java 2.0 allows the user to specify the density and temperature evolution for an r-process simulation. Defining how the...

  10. School and Web 2.0: a critical perspective

    Selwyn, Neil; Gouseti, Anastasia

    2009-01-01

    Este artículo ofrece una visión general de las implicaciones educativas de las tecnologías web 2.0 en las escuelas, sosteniendo que las representaciones actuales del uso de web 2.0 duplican una vieja tendencia en la educación de reacciones exageradas e ideológicamente lanzadas hacia la tecnología. El artículo concluye argumentando a favor de la necesidad de retener una perspectiva prudente, que no crítica, de las escuelas y web 2.0,buscando encontrar maneras de usar las tecnologías w...

  11. E-Learning 2.0: Learning Redefined

    Kumar, Rupesh

    2009-01-01

    The conventional e-learning approach emphasizes a learning system more than a learning environment. While traditional e-learning systems continue to be significant, there is a new set of services emerging, embracing the philosophy of Web 2.0. Known as e-learning 2.0, it aims to create a personalized learning environment. E-learning 2.0 combines the use of discrete but complementary tools and web services to support the creation of ad-hoc learning communities. This paper discusses the influenc...

  12. Effects of electromagnetic radiation in the range 20-300 MHz on the vacuolar potential of characean cells

    Barsoum, Y.H.; Pickard, W.F.

    1982-01-01

    A giant cell (circa 10 mm long) of Chara braunii or Nitella flexilis was placed in a microstrip exposure apparatus, and the vacuolar potential at one end was monitored with a micropipette while the other end was exposed to pulses of VHF radiation at electric field strengths up to 6250 V/m. With suitable filtering and signal averaging, offsets of the vacuolar potential could be detected in real time and at levels as low as 1 microV. The only effect that has been reproducibly observed in the carrier frequency range 20-300 MHz was the slow ramp-like hyperpolarization previously reported (Pickard and Barsoum, 1981) and tentatively attributed to electromagnetic heating of the system. The slopes of these ramps became more pronounced with increasing frequency and behaved in accordance with theoretical predictions.

  13. $\\mathbf{\\alpha}$-induced reaction cross sections in the mass range $\\mathbf{A \\approx 20 - 50}$: a critical review

    Mohr, Peter

    2016-01-01

    In a recent review it was shown that the cross sections of $\\alpha$-induced reactions in the $A \\approx 20 - 50$ mass range follow a general and smooth trend in most cases. For comparison of cross sections of different targets at various energies the method of reduced cross sections $\\sigma_{\\rm{red}}$ and reduced energies $E_{\\rm{red}}$ was used. Four outliers were identified: $^{36}$Ar and $^{40}$Ar with unusally small cross sections and $^{23}$Na and $^{33}$S with unusually large cross sections. New data for $^{23}$Na were presented at this NPA-7 conference; contrary to the previous data, these new data fit into the general systematics. In addition, a relation between the most effective energy $E_0$ for astrophysical reaction rates (the so-called Gamow window) and the reduced energy $E_{\\rm{red}}$ is presented.

  14. Hauser-Feshbach calculations of neutron-induced reaction cross sections for 52Cr in 6-20 MeV neutron energy range

    Calculations of cross sections of neutron induced reactions for 52Cr in 6-20 MeV energy range have been performed using Hauser-Feshbach code developed by the author. The calculations include cross sections of (n,n'), (n.np), (n,2n), (n,p), (n,pn), (n,pγ), (n,α), (n,αγ) and (n, αn) reactions induced in 52Cr. The calculations have been compared with measurements and evaluations. (author). 30 refs, 11 figs, 2 tabs

  15. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions

    Depleted uranium that included carbide inclusions was sputtered with 30keV gallium ions or 16kev cesium ions to depths much greater than the ions’ range, i.e. using steady state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U86Ga14, (UC)70Ga30 and U81Cs9, (UC)79Cs21, respectively.

  16. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U₈₆Ga₁₄, (UC)₇₀Ga₃₀ and U₈₁Cs₉, (UC)₇₉Cs₂₁, respectively.

  17. The tensile properties of alloys 800H and 617 in the range 20 to 950deg C

    The tensile properties of Alloy 800H and Alloy 617 in the solution treated condition and after ageing or carburization have been determined for the temperature range 20 to 950deg C. It was found that ageing at 900deg C prior to testing led to an increase in strength and a decrease in ductility at test temperatures up to 700deg C. Above 700deg C, there was no significant difference between the tensile properties of solution treated and aged material. Carburization caused a severe loss of ductility in both alloys at temperatures of 20 to around 800deg C, but the ductility increased sharply at test temperatures above 800deg C, accompanied by a change in the fracture mode from fracture of the carbide particles themselves to void formation and separation at the carbide/matrix interface. The correlation between tensile properties and creep data was investigated in tests carried out at different strain rates. Reasonable agreement was found at 800 to 950deg C for Alloy 617 and at 800 to 900deg C for Alloy 800H. Strain ageing effects were observed in both alloys at some temperatures and strain rates; these effects were serrated flow, negative strain rate sensitivity, peaks in the normalized UTS-temperature curves and plateaus in the elongation-temperature curves. The experimental results were interpreted in the light of two current models for strain ageing, the dislocation-dislocation interaction model and the dislocation-solute interaction model. (orig.)

  18. Scintillation properties of Ba0.20Sr0.80Cl2 single crystal

    New scintillation crystal of a Ba0.20Sr0.80Cl2 grown by the Czochralski technique is reported. The grown crystal was cut into a size of 10x10x10 mm3. The lattice parameter of the grown crystal is a=b=c=7.041 A and the crystal structure is cubic. The luminescence and scintillation properties of the Ba0.20Sr0.80Cl2 crystal were studied. The luminescent characteristics were measured with ultraviolet (UV) light and X-ray source to study the emission spectra of the crystal. Scintillation properties of the crystal such as pulse height spectra, energy resolution, α/β ratio, light output, proportionality curve, and fluorescence decay time were measured with the various radioactive γ-ray sources and α-source at room temperature. The light output of the crystal was compared with that of the CsI(Tl) crystal and the absolute light output was measured with avalanche photodiode (APD). While the light output of the crystal was less than that of the CsI(Tl), the energy resolution was approximately 6.9% for 137Cs 662 keV γ-ray with PMT which is similar to that of the CsI(Tl) crystal for 137Cs γ-rays. (author)

  19. Guidelines for the undergraduate psychology major: Version 2.0.

    2016-01-01

    The APA Guidelines for the Undergraduate Psychology Major: Version 2.0 (henceforth Guidelines 2.0; APA, 2013) represents a national effort to describe and develop high-quality undergraduate programs in psychology. The task force charged with the revision of the original guidelines for the undergraduate major examined the success of the document's implementation and made changes to reflect emerging best practices and to integrate psychology's work with benchmarking scholarship in higher education. Guidelines 2.0 abandoned the original distinction drawn between psychology-focused skills and psychology skills that enhance liberal arts development. Instead, Guidelines 2.0 describes five inclusive goals for the undergraduate psychology major and two developmental levels of student learning outcomes. Suggestions for assessment planning are provided for each of the five learning goals. PMID:26866986

  20. Enterprise 2.0 and the Future of Business

    MICHAEL O'NEILL

    2006-01-01

    @@ If you are still struggling to get a clear understanding of exactly what Web 2.0 means and how the current hype surrounding social networking and information sharing websites are relevant to your company's needs, fear not.

  1. The dynamic range of LZ

    Yin, J.

    2016-02-01

    The electronics of the LZ experiment, the 7-tonne dark matter detector to be installed at the Sanford Underground Research Facility (SURF), is designed to permit studies of physics where the energies deposited range from 1 keV of nuclear-recoil energy up to 3,000 keV of electron-recoil energy. The system is designed to provide a 70% efficiency for events that produce three photoelectrons in the photomultiplier tubes (PMTs). This corresponds approximately to the lowest energy threshold achievable in multi-tonne time-projection chambers, and drives the noise specifications for the front end. The upper limit of the LZ dynamic range is defined to accommodate the electroluminescence (S2) signals. The low-energy channels of the LZ amplifiers provide the dynamic range required for the tritium and krypton calibrations. The high-energy channels provide the dynamic range required to measure the activated Xe lines.

  2. The dynamic range of LZ

    The electronics of the LZ experiment, the 7-tonne dark matter detector to be installed at the Sanford Underground Research Facility (SURF), is designed to permit studies of physics where the energies deposited range from 1 keV of nuclear-recoil energy up to 3,000 keV of electron-recoil energy. The system is designed to provide a 70% efficiency for events that produce three photoelectrons in the photomultiplier tubes (PMTs). This corresponds approximately to the lowest energy threshold achievable in multi-tonne time-projection chambers, and drives the noise specifications for the front end. The upper limit of the LZ dynamic range is defined to accommodate the electroluminescence (S2) signals. The low-energy channels of the LZ amplifiers provide the dynamic range required for the tritium and krypton calibrations. The high-energy channels provide the dynamic range required to measure the activated Xe lines

  3. Driving Web 2.0 Tool Adoption in Agricultural Education

    Constantina Costopouloul; Maria Ntaliani; Alexander Sideridis

    2013-01-01

    The new opportunities for collaboration, participatory content creation and communication offered through the advancements of Web 2.0, such as social networking, blogs, wikis, video sharing and other, are creating new learning models. In turn, tutors cannot ignore this trend and have to bear the responsibility of incorporating Web 2.0 tools in formal, informal, work-based and vocational education and approach their students in a very familiar and favourable way. In this context, this paper tr...

  4. Informationskompetenz 2.0 und das Verschwinden des Nutzers

    Hapke, Thomas

    2007-01-01

    Ausgehend von einer sich wandelnden Rolle des Nutzers von Informationssystemen im Web 2.0 wird das Konzept Informationskompetenz kritisch hinterfragt. Fünf Thesen zur Informationskompetenz 2.0, verbunden mit Anregungen auf weiterführende Literatur, schlagen einen Perspektivwechsel der in deutschen Bibliotheken vorherrschenden Sicht auf Informationskompetenz hin zu einem ganzheitlicheren Verständnis von Informations- und Lernprozessen vor. Starting from the changing role of the user in info...

  5. Zend framework 2.0 by example beginner's guide

    Shasankar, Krishna

    2013-01-01

    Zend Framework 2.0 by Example: Beginner's Guide is a step-by-step guide that aims to empower you to build web applications packed with some really exciting features using Zend Framework 2.0.If you are a PHP Developer who is new to Zend Framework, but you want to get hands-on with the product quickly, this book is for you. Basic knowledge of object oriented programming with PHP is expected.

  6. RadCat 2.0 User Guide.

    Osborn, Douglas.; Weiner, Ruth F.; Mills, George Scott; Hamp, Steve C.; O' Donnell, Brandon, M.; Orcutt, David J.; Heames, Terence J.; Hinojosa, Daniel

    2005-01-01

    This document provides a detailed discussion and a guide for the use of the RadCat 2.0 Graphical User Interface input file generator for the RADTRAN 5.5 code. The differences between RadCat 2.0 and RadCat 1.0 can be attributed to the differences between RADTRAN 5 and RADTRAN 5.5 as well as clarification for some of the input parameters. 3

  7. Happiness and the Family 2.0 Paradigm

    Mocan, Rodica; Racorean, Stefana

    Does new media technology have the potential to make us happier? This paper explores the influence of new information communication technologies on family life satisfaction while analyzing some of the factors that determine changes in the way we live our lives in the information age. Family 2.0 is the new paradigm of family life and the emergence of Web 2.0 type of applications is at the very core of its existence.

  8. Electron stopping power and mean free path in organic compounds over the energy range of 20-10,000 eV

    Tan, Zhenyu; Xia, Yueyuan; Zhao, Mingwen; Liu, Xiangdong; Li, Feng; Huang, Boda; Ji, Yanju

    2004-07-01

    An empirical method to obtain optical energy loss functions is presented for a large number of organic compounds, for which optical data are not available, on the basis of structure feature analysis of the existed optical energy loss functions for certain organic compounds. The optical energy loss functions obtained by using this method are in good agreement with the experimental data. Based on the Penn's statistical model, a set of systematic expressions have been given for the calculation of the stopping powers and mean free paths of electrons penetrating into the organic compounds in the energy range of E⩽10 keV. Detailed comparison of the calculated data with other theoretical results is presented. The stopping powers and mean free paths for a group of important polymers, without available optical data, have been calculated. In the calculations, three different cases have been considered, i.e. exchange correction not being considered, Ashley exchange correction being involved, and Born-Ochkur exchange correction being included. The results indicate that for these compounds the calculated stopping powers agree well with those obtained by using Bethe-Bloch theory at high-energy limit E=10 keV, as expected for a stopping power theory that should be converged to Bethe-Bloch theory at high energies.

  9. Comparison of Cervical Range of Motion and Cervical FRR between Computer Users in Their Early and Late 20s in Korea

    Yoo, Won-gyu

    2014-01-01

    [Purpose] This study compared the cervical range of motion and cervical FRR between computer users in their early and late 20s in Korea. [Subjects] Eleven male and 7 female computer users in their early 20s and 10 male and 6 female computer users in their late 20s participated in this study. [Methods] All cervical ROM measurements were taken with a Cervical Range of Motion Instrument. Electromyographic (EMG) data were obtained for analyzing the FR ratio. [Results] Cervical extension, right an...

  10. Emergent Learning and Learning Ecologies in Web 2.0

    Roy Williams

    2011-03-01

    Full Text Available This paper describes emergent learning and situates it within learning networks and systems and the broader learning ecology of Web 2.0. It describes the nature of emergence and emergent learning and the conditions that enable emergent, self-organised learning to occur and to flourish. Specifically, it explores whether emergent learning can be validated and self-correcting and whether it is possible to link or integrate emergent and prescribed learning. It draws on complexity theory, communities of practice, and the notion of connectivism to develop some of the foundations for an analytic framework, for enabling and managing emergent learning and networks in which agents and systems co-evolve. It then examines specific cases of learning to test and further develop the analytic framework.The paper argues that although social networking media increase the potential range and scope for emergent learning exponentially, considerable effort is required to ensure an effective balance between openness and constraint. It is possible to manage the relationship between prescriptive and emergent learning, both of which need to be part of an integrated learning ecology.

  11. SPHY v2.0: Spatial Processes in HYdrology

    Terink, W.; Lutz, A. F.; Simons, G. W. H.; Immerzeel, W. W.; Droogers, P.

    2015-07-01

    This paper introduces and presents the Spatial Processes in HYdrology (SPHY) model (v2.0), its development background, its underlying concepts, and some example applications. SPHY has been developed with the explicit aim of simulating terrestrial hydrology on flexible scales, under various physiographical and hydroclimatic conditions, by integrating key components from existing and well-tested models. SPHY is a spatially distributed leaky bucket type of model, and is applied on a cell-by-cell basis. The model is written in the Python programming language using the PCRaster dynamic modeling framework. SPHY (i) integrates most hydrologic processes, (ii) has the flexibility to be applied in a wide range of hydrologic applications, and (iii) on various scales, and (iv) can easily be implemented. The most relevant hydrological processes that are integrated into the SPHY model are rainfall-runoff processes, cryosphere processes, evapotranspiration processes, the dynamic evolution of vegetation cover, lake/reservoir outflow, and the simulation of root-zone moisture contents. Studies in which the SPHY model was successfully applied and tested are described in this paper, including (i) real-time soil moisture predictions to support irrigation management in lowland areas, (ii) climate change impact studies in snow- and glacier-fed river basins, and (iii) operational flow forecasting in mountainous catchments.

  12. SPHY v2.0: Spatial Processes in HYdrology

    W. Terink

    2015-02-01

    Full Text Available This paper introduces and presents the Spatial Processes in HYdrology (SPHY model (v2.0, its development background, its underlying concepts, and some typical applications. The SPHY model is developed using the best components of existing and well-tested simulation models, and is developed with the explicit aim to simulate terrestrial hydrology at flexible scales, under various land use and climate conditions. SPHY is a spatially distributed leaky bucket type of model, and is applied on a cell-by-cell basis. The model is written in the Python programming language using the PCRaster dynamic modelling framework. Compared to other hydrological models, that typically focus on the simulation of streamflow only, the SPHY model has several advantages: it (i integrates most relevant hydrological processes, (ii is setup modular, (iii is easy adjustable and applicable, (iii can easily be linked to remote sensing data, and (iv can be applied for operational as well as strategic decision support. The most relevant hydrological processes that are integrated in the SPHY model are rainfall–runoff processes, cryosphere processes, evapotranspiration processes, the simulation of dynamic vegetational cover, lake/reservoir outflow, and the simulation of rootzone moisture contents. Studies in which the SPHY model was successfully applied and tested are described in this paper, and range from (i real-time soil moisture predictions to support irrigation management in lowland areas, to (ii detailed climate change impact studies in snow and glacier-fed river basins, to (iii operational flow forecasting in mountainous catchments.

  13. Performance of a time-of-flight silicon strip telescope in the temperature range 20 C to -55 C

    Codino, A. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Brunetti, M.T. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Federico, C. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Grimani, C. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Macchiaiolo, T. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Menichelli, M. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Minelli, G. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Miozza, M. [Istituto Nazionale di Fisica Nucleare, Perugia (Italy); Plouin, F. [Laboratoire National Saturne, Gif-Sur-Yvette, Saclay (France)

    1995-10-15

    A cold silicon strip telescope for time-of-flight determination operating at -55 C has been tested using a hadron beam at Saturne II, Saclay. We present performance tests of the telescope, the time-of-flight distributions between pairs of silicon hodoscopes and their dependence on temperature. A detailed description of the apparatus, the refrigerator system and the calibration procedures is also reported. A linear relationship between the time resolution and the temperature of the apparatus is measured. An improvement of a factor 2 in the time-of-flight resolution is observed when the temperature decreases from +20 C to -55 C. (orig.).

  14. Performance of a time-of-flight silicon strip telescope in the temperature range 20 C to -55 C

    A cold silicon strip telescope for time-of-flight determination operating at -55 C has been tested using a hadron beam at Saturne II, Saclay. We present performance tests of the telescope, the time-of-flight distributions between pairs of silicon hodoscopes and their dependence on temperature. A detailed description of the apparatus, the refrigerator system and the calibration procedures is also reported. A linear relationship between the time resolution and the temperature of the apparatus is measured. An improvement of a factor 2 in the time-of-flight resolution is observed when the temperature decreases from +20 C to -55 C. (orig.)

  15. ReefBase 2.0: a contribution to environmental conservation on a global scale

    Halmarick, L.

    1997-01-01

    The 1997 International Year of the Reef sees the release of ReefBase 2.0: a global database on coral reefs and their resources. It provides the most comprehensive and accessible repository of information to date. Containing information on over 7000 coral reefs in more than 123 countries, ReefBase 2.0 offers an extensive range of time-related data pertaining to coastal tourism, benthic environment ecology, fish population statistics, oceanography, socioeconomics, mariculture, and harvest activ...

  16. 20 CFR 636.2 - Protection of informants.

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Protection of informants. 636.2 Section 636.2... AND HEARINGS § 636.2 Protection of informants. (a) Informants. Where possible the identity of any person who has furnished information relating to, or assisted in an investigation of a possible...

  17. Optical potentials for Ne*(3P2,0)-Ar, N2 interactions

    Baudon, J.; Feron, P.; Miniatura, C.; Perales, F.; Reinhardt, J.; Robert, J.; Haberland, H.; Brunetti, B.; Vecchiocattivi, F.

    1991-08-01

    The differential elastic cross sections for Ne*(3P2,0)-Ar and Ne*(3P2,0)-N2 collisions have been measured in crossed beam experiments at 0.064 and 0.318 and at 0.071 and 0.295 eV, collision energies, respectively. These results have been analyzed simultaneously with integral cross sections and total ionization cross sections already available and optical spherical potentials for these two systems have been obtained. These potentials appear to be rather accurate in the distance range from 2.5 to ˜9 and from 3.0 to ˜9 Å for Ne*-Ar and Ne*-N2, respectively. The well depths and equilibrium distances are 5.12 meV and 4.9 Å for Ne*-Ar and 3.56 meV and 5.40 Å for Ne*-N2. The short-range repulsion in both cases exhibits a change in slope which can be correlated with the influence, for the interaction at shorter distances, of the Ne+ core of the metastable atom, which becomes less effective when the intermolecular distance increases. The optical potentials proposed here are given in analytical form suitable for the calculation of dynamical observables of these systems.

  18. MULTI-KEV X-Ray Yields From High-Z Gas Targets Fielded At Omega

    The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at ∼ 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3ω (∼ 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recorded with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.

  19. The LAGRANTO Lagrangian analysis tool - version 2.0

    Sprenger, M.; Wernli, H.

    2015-08-01

    Lagrangian trajectories are widely used in the atmospheric sciences, for instance to identify flow structures in extratropical cyclones (e.g., warm conveyor belts) and long-range transport pathways of moisture and trace substances. Here a new version of the Lagrangian analysis tool LAGRANTO (Wernli and Davies, 1997) is introduced, which offers considerably enhanced functionalities. Trajectory starting positions can be defined easily and flexibly based on different geometrical and/or meteorological conditions, e.g., equidistantly spaced within a prescribed region and on a stack of pressure (or isentropic) levels. After the computation of the trajectories, a versatile selection of trajectories is offered based on single or combined criteria. These criteria are passed to LAGRANTO with a simple command language (e.g., "GT:PV:2" readily translates into a selection of all trajectories with potential vorticity, PV, greater than 2 PVU; 1 PVU = 10-6 K m2 kg-1 s-1). Full versions of this new version of LAGRANTO are available for global ECMWF and regional COSMO data, and core functionality is provided for the regional WRF and MetUM models and the global 20th Century Reanalysis data set. The paper first presents the intuitive application of LAGRANTO for the identification of a warm conveyor belt in the North Atlantic. A further case study then shows how LAGRANTO can be used to quasi-operationally diagnose stratosphere-troposphere exchange events. Whereas these examples rely on the ECMWF version, the COSMO version and input fields with 7 km horizontal resolution serve to resolve the rather complex flow structure associated with orographic blocking due to the Alps, as shown in a third example. A final example illustrates the tool's application in source-receptor analysis studies. The new distribution of LAGRANTO is publicly available and includes auxiliary tools, e.g., to visualize trajectories. A detailed user guide describes all LAGRANTO capabilities.

  20. Mobile Web 2.0 Developing and Delivering Services to Mobile Devices

    Ahson, Syed A

    2010-01-01

    From basic concepts to research grade material, Mobile Web 2.0: Developing and Delivering Services to Mobile Devices provides complete and up-to-date coverage of the range of technical topics related to Mobile Web 2.0. It brings together the work of 51 pioneering experts from around the world who identify the major challenges in Mobile Web 2.0 applications and provide authoritative insight into many of their own innovations and advances in the field. To help you address contemporary challenges, the text details a conceptual framework that provides modeling facilities for context-aware, multi-c

  1. Agriculture, forestry, range, and soils, chapter 2, part C

    1975-01-01

    The feasibility of using microwave systems in agriculture, forestry, range, and soil moisture measurements was studied. Theory and preliminary results show the feasibility of measuring moisture status in the soil. For vegetational resources, crop identification for inventory and for yield and production estimates is most feasible. Apart from moisture- and water-related phenomena, microwave systems are also used to record structural and spatial data related to crops and forests.

  2. Thermodynamic properties of Sm2S3 and SmS2 within wide temperature range

    For the first time using the mixing method in a wide temperature range inthalpies of Sm2S3 and SmS2 are determined. An intense increase of Sm2S3 enthalpy is observed in the high temperature range and the melting point for this compound is determined. The basic thermodynamic characteristics (enthalpy, thermal capacity, entropy, reduced Gibbs energy) of studied sulfides are calculated

  3. Informationskompetenz 2.0 und das Verschwinden des "Nutzers" [Information literacy 2.0 and the disappearance of the user

    Hapke, Thomas

    2007-01-01

    Starting from the changing role of the user in information systems in the Web 2.0 this paper critically questions the concept of information literacy. Five theses on information literacy 2.0 as well as suggestions for further reading offer the possibility to change the perspective of the view on information literacy predominating in German libraries in the direction of a more holistic view of information and learning processes.

  4. Spectrometry of the Rutherford backscattering of ions and the Raman scattering of light in GaS single crystals irradiated with 140-keV H{sub 2}{sup +} ions

    Garibov, A. A.; Madatov, R. S., E-mail: msrahim@mail.ru [Azerbaijan National Academy of Sciences, Institute of Radiation Problems (Azerbaijan); Komarov, F. F.; Pilko, V. V. [Belarus State University, RTCCU of “Nanotechnology and Physical Electronics” (Belarus); Mustafayev, Yu. M.; Akhmedov, F. I.; Jakhangirov, M. M. [Azerbaijan National Academy of Sciences, Institute of Radiation Problems (Azerbaijan)

    2015-05-15

    The methods of the Raman scattering of light and Rutherford backscattering are used to study the degree of structural disorder in layered GaS crystals before and after irradiation with 140-keV H{sub 2}{sup +} ions. It is shown that the distribution of the crystal’s components over depth is homogeneous; for doses as high as 5 × 10{sup 15} cm{sup −2}, the stoichiometric composition of the compound’s components is retained. The experimental value of the critical dose for the beginning of amorphization amounts to about 5 × 10{sup 15} cm{sup −2} and is in accordance with the calculated value. The results obtained by the method of the Raman scattering of light confirm conservation of crystalline structure and the start of the amorphization process.

  5. Onlinestudie: Wissenschaftliches Arbeiten im Web 2.0

    Moskaliuk, Johannes

    2009-07-01

    Full Text Available Das Web 2.0 eröffnet Wissenschaftlerinnen und Wissenschaftlern neue Möglichkeiten mit Wissen und Informationen umzugehen: Das Recherchieren von Informationen und Quellen, der Austausch von Wissen mit anderen, das Verwalten von Ressourcen und das Erstellen von eigenen Inhalten im Web ist einfach und kostengünstig möglich. Dieser Artikel thematisiert die Bedeutung des Web 2.0 für den Umgang mit Wissen und Informationen und zeigt auf, wie durch die Kooperation vieler Einzelner das Schaffen von neuem Wissen und von Innovationen möglich wird. Diskutiert werden der Einfluss des Web 2.0 auf die Wissenschaft und mögliche Vor- und Nachteile der Nutzung. Außerdem wird ein kurzer Überblick über Studien gegeben, die die Nutzung des Web 2.0 in der Gesamtbevölkerung untersuchen.Im empirischen Teil des Artikels werden Methode und Ergebnisse der Befragungsstudie „Wissenschaftliches Arbeiten im Web 2.0“ vorgestellt. Befragt wurden Nachwuchswissenschaftlerinnen und Nachwuchswissenschaftler in Deutschland zur Nutzung des Web 2.0 für die eigene wissenschaftliche Arbeit. Dabei zeigt sich, dass insbesondere die Wikipedia von einem Großteil der Befragten intensiv bis sehr intensiv für den Einstieg in die Recherche verwendet wird. Die aktive Nutzung des Web 2.0, z.B. durch das Schreiben eines eigenen Blogs oder dem Mitarbeiten bei der Online-Enzyklopädie Wikipedia ist bis jetzt noch gering. Viele Dienste sind unbekannt oder werden eher skeptisch beurteilt, der lokale Desktopcomputer wurde noch nicht vom Web als zentraler Speicherort abgelöst.

  6. Low-power 20-meter 3D ranging SPAD camera based on continuous-wave indirect time-of-flight

    Bellisai, S.; Ferretti, L.; Villa, F.; Ruggeri, A.; Tisa, S.; Tosi, A.; Zappa, F.

    2012-06-01

    Three dimensional (3D) image acquisitions is the enabling technology of a great number of applications; culture heritage morphology study, industrial robotics, automotive active safety and security access control are example of applications. The most important feature is the high frame-rate, to detect very fast events within the acquired scenes. In order to reduce the computational complexity, Time-of-Flight algorithms for single sensor cameras are used. To achieve high-frame rate and high distance measurement accuracy it is important to collect the most part of the reflected light using sensor with very high sensitivity, allowing the implementation of a low-power light source. We designed and developed a single-photon detection based 3D ranging camera, capable to acquire distance image up to 22.5 m, with a resolution down to one centimeter. The light source used in this prototype employs 8 laser diodes sinusoidally modulated. The imager used in the application is based on Single-Photon Avalanche Diodes (SPADs) fabricated in a standard CMOS 0.35 μm technology. The sensor has 1024 pixels arranged in a 32x32 squared layout, with overall dimensions of 3.5mm x 3.5mm. The camera acquires 3D images through the continuous-wave indirect Time of Flight (cw-iTOF) technique. The typical frame-rate is 20 fps while the theoretical maximum frame-rate is 5 kfps. The precision is better than 5 cm within 22.5 m range, and can be effectively used in indoor applications, e.g. in industrial environment.

  7. 1- to 10-keV x-ray backlighting of annular wire arrays on the Sandia Z-machine using bent-crystal imaging techniques

    Annular wire array implosions on the Sandia Z-machine can produce >200 TW and 1-2 MJ of soft x rays in the 0.1-10 keV range. The x-ray flux and debris in this environment present significant challenges for radiographic diagnostics. X-ray backlighting diagnostics at 1865 and 6181 eV using spherically-bent crystals have been fielded on the Z-machine, each with a ∼0.6 eVspectral bandpass, 10 (micro)m spatial resolution, and a 4 mm by 20mm field of view. The Z-Beamlet laser, a 2-TW, 2-kJ Nd:glass laser(λ = 527 nm), is used to produce 0.1-1 J x-ray sources for radiography. The design, calibration, and performance of these diagnostics is presented.

  8. 1-to 10-keV x-ray backlighting of annular wire arrays on the Sandia Z-machine using bent-crystal imaging techniques.

    Rambo, Patrick K.; Wenger, David Franklin; Bennett, Guy R.; Sinars, Daniel Brian; Smith, Ian Craig; Porter, John Larry, Jr.; Cuneo, Michael Edward; Rovang, Dean Curtis; Anderson, Jessica E.

    2003-07-01

    Annular wire array implosions on the Sandia Z-machine can produce >200 TW and 1-2 MJ of soft x rays in the 0.1-10 keV range. The x-ray flux and debris in this environment present significant challenges for radiographic diagnostics. X-ray backlighting diagnostics at 1865 and 6181 eV using spherically-bent crystals have been fielded on the Z-machine, each with a {approx}0.6 eVspectral bandpass, 10 {micro}m spatial resolution, and a 4 mm by 20mm field of view. The Z-Beamlet laser, a 2-TW, 2-kJ Nd:glass laser({lambda} = 527 nm), is used to produce 0.1-1 J x-ray sources for radiography. The design, calibration, and performance of these diagnostics is presented.

  9. Library 2.0, information and digital literacies in the light of the contradictory nature of Web 2.0

    Tibor Koltay

    2010-12-01

    Full Text Available Desk research was done to examine the importance of raising awareness of differences between professional content and content produced by the amateurs of the Web 2.0. The commercial nature of Web 2.0 was briefly explained. Questions related to amateurism have been raised and amateur contents characterizing Web 2.0 were contrasted to professional ones. The results show that some principles can be laid down. First of all, the need in literacies of students, teaching staff and researchers is different from that of other categories of users, when the former are fulfilling their professional roles. These needs can be satisfied mainly by services that traditionally have been provided by academic and special libraries, while making use of Web 2.0 tools could mean moving towards the goals of public library users. Second, information literacy and digital literacy alongside with adequately defined Library 2.0 are expedient in the era of Web 2.0 to support user needs by the provision of appropriate library resources and services.

  10. Indico — the Road to 2.0

    Ferreira, P.; Avilés, A.; Dafflon, J.; Mönnich, A.; Trichopoulos, I.

    2015-12-01

    Indico has come a long way since it was first used to organize CHEP 2004. More than ten years of development have brought new features and projects, widening the application's feature set and enabling event organizers to work even more efficiently. While that has boosted the tool's usage and facilitated its adoption by a remarkable 300,000 events (at CERN only), it has also generated a whole new range of challenges, which have been the target of the team's attention for the last 2 years. One of them was that of scalability and the maintainability of the current database solution (ZODB). After careful consideration, the decision was taken to move away from ZODB to PostgreSQL, a relational and widely-adopted solution that will permit the development of a more ambitious feature set as well as improved performance and scalability. A change of this type is by no means trivial in nature and requires the refactoring of most backend code as well as the full rewrite of significant portions of it. We are taking this opportunity to modernize Indico, by employing standard web modules, technologies and concepts that not only make development and maintenance easier but also constitute an upgrade to Indico's stack. The first results are already visible since August 2014, with the full migration of the Room Booking module to the new paradigm. In this paper we explain what has been done so far in the context of this ambitious migration, what have been the main findings and challenges, as well as the main technologies and concepts that will constitute the foundation of the resultant Indico 2.0.

  11. The Lagrangian analysis tool LAGRANTO - version 2.0

    Sprenger, M.; Wernli, H.

    2015-02-01

    Lagrangian trajectories are widely used in the atmospheric sciences, for instance to identify flow structures in extratropical cyclones (e.g., warm conveyor belts) and long-range transport pathways of moisture and trace substances. Here a new version of the Lagrangian analysis tool LAGRANTO (Wernli and Davies, 1997) is introduced, which offers considerably enhanced functionalities: (i) trajectory starting positions can be described easily based on different geometrical and/or meteorological conditions; e.g., equidistantly spaced within a prescribed region and on a stack of pressure (or isentropic) levels; (ii) a versatile selection of trajectories is offered based on single or combined criteria; these criteria are passed to LAGRANTO with a simple command language (e.g., "GT:PV:2" readily translates into a selection of all trajectories with potential vorticity (PV) greater than 2 PVU); and (iii) full versions are available for global ECMWF and regional COSMO data; core functionality is also provided for the regional WRF and UM models, and for the global 20th Century Reanalysis data set. The intuitive application of LAGRANTO is first presented for the identification of a warm conveyor belt in the North Atlantic. A further case study then shows how LAGRANTO is used to quasi-operationally diagnose stratosphere-troposphere exchange events over Europe. Whereas these example rely on the ECMWF version, the COSMO version and input fields with 7 km horizontal resolution are needed to adequately resolve the rather complex flow structure associated with orographic blocking due to the Alps. Finally, an example of backward trajectories presents the tool's application in source-receptor analysis studies. The new distribution of LAGRANTO is publicly available and includes simple tools, e.g., to visualize and merge trajectories. Furthermore, a detailed user guide exists, which describes all LAGRANTO capabilities.

  12. The (3He, tf) as a surrogate reaction to determine (n, f) cross sections in the 10-20 MeV energy range

    The surrogate reaction 238U(3He, tf) is used to determine the 237Np(n, f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ∼761 μg/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. The 237Np(n, f) cross sections, determined indirectly, were compared with the 237Np(n, f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (3He, tf) reaction as a surrogate to extract (n, f) cross sections in the 10-20 MeV equivalent neutron energy range is found to be suitable.

  13. Free E-Textbook "Cartography 2.0"

    Nedjeljko Frančula

    2011-06-01

    Full Text Available Mark Harrower, Anthony C. Robinson, Robert E. Roth and Ben Sheesely wrote the e-textbook Cartography 2.0 and made it available on the Internet at no charge. The textbook’s website (http://Cartography2.org explains their reasoning, which was also published in the Cartographic Perspectives journal (Cartography 2.0: For People Who Make Interactive Maps, Number 64, Fall 2009. They emphasize they were frustrated with traditional textbooks’ inability to keep in touch with web technologies, and they could not locate a comprehensive source of width and depth expected from a professional textbooks. They elaborate on this in detail.

  14. UFe2Zn20: a new uranium intermetallic compound

    A new uranium intermetallic compound, UFe2Zn20, was prepared and characterized by single-crystal X-ray diffraction, 57Fe Moessbauer spectroscopy and magnetization measurements. It crystallizes in the cubic Fd anti 3m space group (a=14.0998(9) A) and is isostructural with CeCr2Al20 (R=0.045, WR2=0.12). Moessbauer spectra, taken between 5 K and room temperature, consist of a symmetric quadrupole doublet with narrow lines, confirming an ordered structure with the iron on only one crystallographic site and showing no magnetic ordering transition above 5 K, in good agreement with magnetization measurements. (orig.)

  15. Free E-Textbook "Cartography 2.0"

    Nedjeljko Frančula; Dražen Tutić

    2011-01-01

    Mark Harrower, Anthony C. Robinson, Robert E. Roth and Ben Sheesely wrote the e-textbook Cartography 2.0 and made it available on the Internet at no charge. The textbook’s website (http://Cartography2.org) explains their reasoning, which was also published in the Cartographic Perspectives journal (Cartography 2.0: For People Who Make Interactive Maps, Number 64, Fall 2009). They emphasize they were frustrated with traditional textbooks’ inability to keep in touch with web technologies, and th...

  16. The unlubricated reciprocating sliding wear of 316 stainless steel in C02 in the temperature range 20 to 6000C

    The friction and wear behaviour of 316 stainless steel in C02 has been investigated in the load range 8 - 5ON from 20 to 6000C. Wear transitions occurred at all temperatures but were load dependent. At and below 3000C wear transitions only took place at low leads whereas above 3000C transitions were seen al all loads. The low temperature wear transition, giving an order of magnitude decrease in wear rate was associated with a change in friction behaviour. The friction force across the specimen was initially widely fluctuating and varied from cycle to cycle. After a time, which did not necessarily coincide with the wear transition the cyclic variation in the friction force become much less. This smoother sliding is thought to indicate a trend to oxide -oxide contacts. At higher temperatures wear transitions result in a two orders of magnitude reduction in wear. The corresponding friction transition was similar to the low temperature friction change but also included a marked temporary drop in the coefficient of friction. (author)

  17. Enthalpy relaxation kinetics of Ge20Te(80-y)Sey far-infrared glasses in the glass transition range

    Svoboda, Roman; Málek, Jiří

    2016-06-01

    Differential scanning calorimetry was used to study enthalpy relaxation kinetics of the Ge20Te(80-y)Sey infrared chalcogenide glasses for the compositional range y = 0-8. The relaxation behaviour was described in terms of the phenomenological Tool-Narayanaswamy-Moynihan (TNM) model. The direct curve-fitting procedure was used to determine the values of TNM parameters. Compositional evolution of the TNM parameters was interpreted with respect to the involved structural entities and their motions. Based on the joint Raman scattering study, the addition of Se leads to increased amount of edge-shared GeTe4-xSex tetrahedra. While the primary structural basis for the relaxation movements appears not to be affected by addition of Se (constant value of non-linearity), changes of the non-exponentiality parameter indicate increased structural variability occurring within the groups of directly interlinked tetrahedra, which were found to carry the main portion of relaxation movements. Increased activation energy was explained by the presence of significantly stronger Ge-Se bonds and increased amount of edge-shared tetrahedra.

  18. Pilots 2.0: DIRAC pilots for all the skies

    Stagni, F.; Tsaregorodtsev, A.; McNab, A.; Luzzi, C.

    2015-12-01

    In the last few years, new types of computing infrastructures, such as IAAS (Infrastructure as a Service) and IAAC (Infrastructure as a Client), gained popularity. New resources may come as part of pledged resources, while others are opportunistic. Most of these new infrastructures are based on virtualization techniques. Meanwhile, some concepts, such as distributed queues, lost appeal, while still supporting a vast amount of resources. Virtual Organizations are therefore facing heterogeneity of the available resources and the use of an Interware software like DIRAC to hide the diversity of underlying resources has become essential. The DIRAC WMS is based on the concept of pilot jobs that was introduced back in 2004. A pilot is what creates the possibility to run jobs on a worker node. Within DIRAC, we developed a new generation of pilot jobs, that we dubbed Pilots 2.0. Pilots 2.0 are not tied to a specific infrastructure; rather they are generic, fully configurable and extendible pilots. A Pilot 2.0 can be sent, as a script to be run, or it can be fetched from a remote location. A pilot 2.0 can run on every computing resource, e.g.: on CREAM Computing elements, on DIRAC Computing elements, on Virtual Machines as part of the contextualization script, or IAAC resources, provided that these machines are properly configured, hiding all the details of the Worker Nodes (WNs) infrastructure. Pilots 2.0 can be generated server and client side. Pilots 2.0 are the “pilots to fly in all the skies”, aiming at easy use of computing power, in whatever form it is presented. Another aim is the unification and simplification of the monitoring infrastructure for all kinds of computing resources, by using pilots as a network of distributed sensors coordinated by a central resource monitoring system. Pilots 2.0 have been developed using the command pattern. VOs using DIRAC can tune pilots 2.0 as they need, and extend or replace each and every pilot command in an easy way. In this

  19. Forward-to-backward asymmetry of the (γ,n) reaction in the energy range 20-30 MeV

    The forward-to-backward asymmetry of neutrons emitted in the (γ,n) reactions on /sup nat/Pb and /sup nat/Cd targets was measured for photons in the range of 20 to 30 MeV, where the isovector quadrupole giant resonance is expected to lie. The asymmetry was observed to increase from small values (≅0.2) to large ones (≅0.6 and 0.8) for /sup nat/Cd and /sup nat/Pb, respectively. This phenomenon is interpreted as the interference between E1 and E2 amplitudes. From an analysis of the asymmetry the excitation energies of the E2 isovector resonances were estimated to be 23.5 +- 1.5 and 26.5 +- 1.5 MeV for the Pb and Cd nuclei, respectively. The E2 isovector resonances are found to be considerably wider than the E1 resonances. 36 refs., 15 figs., 4 tabs

  20. Luminescence excitation characteristics of Ca-, Na- and K-aluminosilicates (feldspars), in the stimulation range 20-500 eV: optical detection of XAS

    Poolton, N R J; Quinn, F M; Pantos, E; Andersen, C E; Bøtter-Jensen, L; Johnsen, O; Murray, A S

    2003-01-01

    We demonstrate that the visible/UV luminescence from common feldspar crystals (NaAlSi sub 3 O sub 8 , KAlSi sub 3 O sub 8 and CaAl sub 2 Si sub 2 O sub 8) can be used to detect detailed L-edge and associated near-edge absorption structure of the main constituent atoms (Ca, K, Na, Al, Si), when exciting in the energy range 20-500 eV. Comparisons of the spectral features are drawn with similar measurements made on the associated materials SiO sub 2 , Al sub 2 O sub 3 and CaCO sub 3. The potential for using optically detected x-ray absorption spectroscopy as a method for identifying the luminescent components of mixed mineral samples is considered.

  1. Luminescence excitation characteristics of Ca-, Na- and K-aluminosilicates (feldspars), in the stimulation range 20-500 eV: optical detection of XAS

    We demonstrate that the visible/UV luminescence from common feldspar crystals (NaAlSi3O8, KAlSi3O8 and CaAl2Si2O8) can be used to detect detailed L-edge and associated near-edge absorption structure of the main constituent atoms (Ca, K, Na, Al, Si), when exciting in the energy range 20-500 eV. Comparisons of the spectral features are drawn with similar measurements made on the associated materials SiO2, Al2O3 and CaCO3. The potential for using optically detected x-ray absorption spectroscopy as a method for identifying the luminescent components of mixed mineral samples is considered

  2. Politische Bildung und das Web 2.0

    Heike Schaumburg

    2011-08-01

    Full Text Available Aktuell erhält die Diskussion um die Rolle des Internet in der Politischen Bildung neuen Auftrieb durch die Entwicklung der sogenannten Web-2.0- Technologien, die im Vergleich zum Web 1.0 ein erheblich grösseres Potenzial zur Mitgestaltung politischer Inhalte und Prozesse und bzw. zur Partizipation bieten, aber auch neue Möglichkeiten der Kommunikation und Vernetzung eröffnen. In der vorliegenden Studie wird der Frage nachgegangen, inwieweit das Internet und speziell das Web 2.0 in der Lage sind, die in die Technik gesetzten Hoffnungen zu erfüllen. Dabei wird zunächst ausgelotet, welche Potenziale das Web 2.0 für die Politische Bildung mit Blick auf ihre didaktische Gestaltung bieten könnte. Im Anschluss daran wird auf der Basis einer Analyse des Internet-Angebots der traditionellen Anbieter Politischer Bildung (Bundes- und Landeszentralen für Politische Bildung, politische Stiftungen sowie von Internetportalen im Bereich Politische Bildung festgestellt, welche Verbreitung Web-2.0-Angebote gegenwärtig besitzen. Schliesslich wird auf der Grundlage einer Nutzerbefragung an knapp 300 Teilnehmern virtueller politischer Bildungsangebote einer politischen Stiftung der Frage nachgegangen, wie Web-2.0-Angebote in der Politischen Bildungsarbeit aus Nutzersicht beurteilt werden.

  3. Mobility2.0: co-operative ITS systems for enhanced electric vehicle mobility

    Heijenk, G.; Dimitrova, D.C.; Brogle, M.; T. Braun; Heijenk, G.J.

    2013-01-01

    Mobility2.0 will develop and test an in-vehicle commuting assistant for FEV mobility, resulting in more reliable and energy-efficient electro-mobility. In order to achieve a maximum impact, Mobility2.0 takes an integrated approach of ad- dressing the main bottlenecks of urban FEV mobility: range anxiety related to the limited FEV range, scarcity of parking spaces with public recharging spots, and the congestion of urban roads. Our integrated approach means the applica- tion developed by Mobil...

  4. Mobility 2.0: Co-Operative ITS Systems for Enhanced Personal Electromobility

    Solar, Alma; Bolovinou, Anastasia; Heijenk, Geert; Lasgouttes, Jean-Marc; Giménez, Rafael

    2013-01-01

    Mobility2.0 is an ITS project aiming at developing and testing an in-vehicle commuting assistant for FEV mobility, resulting in more reliable and energy-efficient electro-mobility. In order to achieve a maximum impact, Mobility2.0 takes an integrated approach of addressing the main bottlenecks of urban FEV mobility: 'range anxiety' related to the limited FEV range, scarcity of parking spaces with public recharging spots and the congestion of urban roads. Our integrated approach means that the...

  5. Mobility 2.0: co-operative ITS systems for enhanced personal electromobility

    Solar, Alma; Bolovinou, Anastasia; Heijenk, Geert; Lasgouttes, Jean-Marc; Giménez, Rafael

    2013-01-01

    Mobility2.0 is an ITS project aiming at developing and testing an in-vehicle commuting assistant for FEV mobility, resulting in more reliable and energy-efficient electro-mobility. In order to achieve a maximum impact, Mobility2.0 takes an integrated approach of addressing the main bottlenecks of urban FEV mobility: 'range anxiety' related to the limited FEV range, scarcity of parking spaces with public recharging spots and the congestion of urban roads. Our integrated approach means that the...

  6. Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: Studies of some biological molecules in the energy range 1 keV-20 MeV

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    , linolenic, arachidonic, and arachidic acids), nucleotide bases (adenine, guanine, cytosine, uracil, and thymine), and carbohydrates (glucose, sucrose, raffinose, and starch). The Z(PEA, eff) and Z(PI, eff) values have been found to change with energy and composition of the biological molecules. The energy...

  7. Incorporating Web 2.0 Technologies from an Organizational Perspective

    Owens, R.

    2009-12-01

    The Arctic Research Consortium of the United States (ARCUS) provides support for the organization, facilitation, and dissemination of online educational and scientific materials and information to a wide range of stakeholders. ARCUS is currently weaving the fabric of Web 2.0 technologies—web development featuring interactive information sharing and user-centered design—into its structure, both as a tool for information management and for educational outreach. The importance of planning, developing, and maintaining a cohesive online platform in order to integrate data storage and dissemination will be discussed in this presentation, as well as some specific open source technologies and tools currently available, including: ○ Content Management: Any system set up to manage the content of web sites and services. Drupal is a content management system, built in a modular fashion allowing for a powerful set of features including, but not limited to weblogs, forums, event calendars, polling, and more. ○ Faceted Search: Combined with full text indexing, faceted searching allows site visitors to locate information quickly and then provides a set of 'filters' with which to narrow the search results. Apache Solr is a search server with a web-services like API (Application programming interface) that has built in support for faceted searching. ○ Semantic Web: The semantic web refers to the ongoing evolution of the World Wide Web as it begins to incorporate semantic components, which aid in processing requests. OpenCalais is a web service that uses natural language processing, along with other methods, in order to extract meaningful 'tags' from your content. This metadata can then be used to connect people, places, and things throughout your website, enriching the surfing experience for the end user. ○ Web Widgets: A web widget is a portable 'piece of code' that can be embedded easily into web pages by an end user. Timeline is a widget developed as part of the

  8. The Space Complexity of 2-Dimensional Approximate Range Counting

    Wei, Zhewei; Yi, Ke

    2013-01-01

    with additive error εn. A well-known solution for this problem is the ε-approximation. Informally speaking, an ε-approximation of P is a subset A ⊆ P that allows us to estimate the number of points in P ∩ R by counting the number of points in A ∩ R. It is known that an ε-approximation of size exists for any P...... with respect to orthogonal ranges, and the best lower bound is . The ε-approximation is a rather restricted data structure, as we are not allowed to store any information other than the coordinates of a subset of points in P. In this paper, we explore what can be achieved without any restriction on the data...

  9. Search of a cyclotron line at 70 keV from Crab Nebula

    An observation of Crab Nebula was made during a transmediterranean balloon flight launched on August 26, 1979 from Milo Base. The hard x-ray experiment carried a payload consisting of two multiwire proportional counters having a geometric area of 900 cm2 each. A single transit scan of the source was performed on the Crab Nebula region at a float altitude of 2.9 mbs. The preliminary results indicate the existence of an excess flux between 64 - 76 keV above the expected value of Esup(-2.0) power law

  10. WEB 2.0 Social Network Sites and Facebook Marketing

    Andreas Chang

    2011-10-01

    Full Text Available The use of Web 2.0 and Social Network Sites (SNS has become an amazing phenomenon. In fact, one of the fastest-growing arenas of the World Wide Web is the space of so-called social networking sites. Face book, Tweeter, MySpace and other Social Network Sites have huge population of users. Almost seven hundred million people use Facebook, and hundreds of million others use other social networking sites. More and more advertisers switch their marketing budget to these SNS. This study contributes to our understanding of the Web 2.0 and the use of social networking websites by examining available literature. It seeks to understand what Web 2.0 and SNS mean, the trends, its functions and how they can be leveraged for marketing purposes.

  11. Adoption of Web 2.0 tools in distance education

    Yasemin Koçak Usluel

    2009-07-01

    Full Text Available This study has two purposes. First is to explain possible educational utilization of Web 2.0 tools, namely blogs, wikis, podcasts and social networks, from the point of importance of interaction for distance education. The second purpose of this study is to investigate adoption process of Web 2.0 tools in distance education by defining theories and models which have different construct that effect this process. Because the nature and structure of both distance education and Web 2.0 include multifaceted and dynamic variables, the limitation of utilization from only single diffusion, adoption or acceptance model or theory is underlined and it is proposed to handle a holistic view or using different models and theories suitable for research variables.

  12. Politische Bildung und das Web 2.0

    Heike Schaumburg

    2011-01-01

    Aktuell erhält die Diskussion um die Rolle des Internet in der Politischen Bildung neuen Auftrieb durch die Entwicklung der sogenannten Web-2.0- Technologien, die im Vergleich zum Web 1.0 ein erheblich grösseres Potenzial zur Mitgestaltung politischer Inhalte und Prozesse und bzw. zur Partizipation bieten, aber auch neue Möglichkeiten der Kommunikation und Vernetzung eröffnen. In der vorliegenden Studie wird der Frage nachgegangen, inwieweit das Internet und speziell das Web 2.0 in der Lage s...

  13. UML 2.0 Pocket Reference UML Syntax and Usage

    Pilone, Dan

    2006-01-01

    Globe-trotting travelers have long resorted to handy, pocket-size dictionaries as an aid to communicating across the language barrier. Dan Pilone's UML 2.0 Pocket Reference is just such an aid for on-the-go developers who need to converse in the Unified Modeling Language (UML). Use this book to decipher the many UML diagrams you'll encounter on the path to delivering a modern software system. Updated to cover the very latest in UML, you'll find coverage of the following UML 2.0 diagram types: Class diagramsComponent diagrams*Sequence diagrams*Communication diagrams*Timing diagrams*Interactio

  14. National destination marketing organisations and Web 2.0

    Jim Hamill; Daniela Attard; Alan Stevenson

    2009-01-01

    National destination marketing organisations and Web 2.0 - Based on a detailed review of 25 web sites, supported by in-depth personal interviews, this paper evaluates the strategic response of European DMOs to the global marketing opportunities and threats presented by the rapid growth of Web 2.0. The main conclusion is that national DMOs, from the leading tourist destinations in Europe, have made only limited progress in this area. Much still needs to be done before they are fully utilising ...

  15. Semantic web technologies for enterprise 2.0

    Passant, A

    2010-01-01

    In this book, we detail different theories, methods and implementations combining Web 2.0 paradigms and Semantic Web technologies in Enterprise environments. After introducing those terms, we present the current shortcomings of tools such as blogs and wikis as well as tagging practices in an Enterprise 2.0 context. We define the SemSLATES methodology and the global vision of a middleware architecture based on Semantic Web technologies and Linked Data principles (languages, models, tools and protocols) to solve these issues. Then, we detail the various ontologies that we build to achieve this g

  16. Heterogeneous computing with OpenCL 2.0

    Kaeli, David R; Schaa, Dana; Zhang, Dong Ping

    2015-01-01

    Heterogeneous Computing with OpenCL 2.0 teaches OpenCL and parallel programming for complex systems that may include a variety of device architectures: multi-core CPUs, GPUs, and fully-integrated Accelerated Processing Units (APUs). This fully-revised edition includes the latest enhancements in OpenCL 2.0 including: Shared virtual memory to increase programming flexibility and reduce data transfers that consume resources Dynamic parallelism which reduces processor load and avoids bottlenecks Improved imaging support and integration with OpenGL  Designed to work on multiple platfor

  17. Conceptos y Aplicaciones de la Web 2.0

    C. Naval; Cruz, R.E. (Reyna Esmeralda); S. Lara

    2010-01-01

    La sociedad evoluciona y con ella las formas de comunicación e interacción. Uno de los cambios que está teniendo más impacto social es probablemente el uso de la web y sus aplicaciones actuales, a lo que denominamos Web 2.0. En este capítulo desarrollamos el concepto Web 2.0 siguiendo a O'Reilly, además de algunas de sus aplicaciones. Asimismo, se verán algunos enfoques del futuro de la web y las consecuencias que trae esta nueva forma de comunicación e interacción.

  18. Formación Web 2.0

    Universidad de Salamanca (España). SCOPEO

    2009-01-01

    [ES] Este número inaugural de la serie monográfica del Observatorio de la actividad, la innovación y las tendencias en la Formación en Red, SCOPEO, busca analizar y estimar el valor formativo de las actuales aplicaciones sociales de la Web, caracterizadas bajo el término de Web 2.0, que definen un conjunto de tendencias emergentes sobre las que es necesario repensar los procesos de formación en red. El monográfico contiene tres secciones. La primera, “La Web 2.0 o la evolución social de...

  19. [Adolescents in Web 2.0: risks and chances ].

    Salisch, Maria von

    2014-01-01

    That almost all adolescents possess an individual access to the internet and that they use it every day, lays the foundation for the improved means of self presentation and participation that are known by the notion of Web 2.0. Social networks and other interactive internet formats give rise to new risks like cyber mobbing which is the topic of three contributions. At the same time, Web 2.0 offers chances in the form of online counseling and online therapy that cater to the preferences of media-friendly target group of adolescents. PMID:24877775

  20. Supersymmetric solutions of $N=(2,0)$ Topologically Massive Supergravity

    Deger, Nihat Sadik

    2016-01-01

    We first make a Killing spinor analysis for a general three-dimensional off-shell $N=(2,0)$ supergravity and find conditions for a bosonic background to preserve some supersymmetry . We then consider a particular model, namely $N=(2,0)$ topologically massive supergravity and impose its field equations. By making a suitable ansatz on metric functions we find a large class of solutions that include spacelike, timelike and null warped $AdS_3$ among others. Isometric quotients of spacelike and timelike squashed $AdS_3$ solutions yield extremal black holes without closed causal curves.