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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;

    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....

  9. 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....

  10. 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.)

  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 {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.

  13. 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

  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. 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

  17. 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.

  18. 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

  19. 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...

  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. 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

  19. 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)

  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. 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)

  14. 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...

  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. 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.

  5. 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.

  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. 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%

  8. 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).

  9. 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.

  10. 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)

  11. 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".

  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. 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

  19. 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.

  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. 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.

  18. 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 ...

  19. 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

  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. 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

  2. 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.

  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. 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....

  13. 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.

  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. 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.

  2. 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.

  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. 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.

  8. 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/

  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. 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.

  14. 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)

  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. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  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...